Karen Burns Podiatry in Boolaroo, New South Wales, Australia | Podiatrist

Karen Burns Podiatry

Locality: Boolaroo, New South Wales, Australia

Phone: +61 2 4958 5694

Address: 58 Main Road 2284 Boolaroo, NSW, Australia

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25.01.2022 Just had a short article on plantar fat pad atrophy published in the July 2020 issue of Podiatry Today magazine. I believe plantar fat atrophy is often over-looked as an etiology of plantar heel and plantar forefoot pain.

25.01.2022 What can you do to help in this process? Psychosocial adjustment to diabetes-related lower limb amputation https://podiatryarena.com/index.php

23.01.2022 Dorsal Midfoot Interosseous Compression Syndrome (DMICS) Dr. Kirby first described Dorsal Midfoot Interosseous Compression Syndrome (DMICS) over 20 years ago in... his February 1997 Precision Intricast Newsletter. Patients with DMICS complain of pain along the dorsal aspects of their midfoot joints during weightbearing activities. Upon taking the history, patients with DMICS point to the area of the metatarsal-cuneiform joints, navicular-cuneiform joints, and sometimes to the area of the metatarsal-cuboid joint as the source of most of their pain. Much less frequently, the pain is noted more proximally, in the dorsal aspects of either the talo-navicular or calcaneo-cuboid joints. The pain generally worsens with increased weightbearing activities and patients report the pain from DMICS will either occur just before heel off and/or during propulsion of walking gait. Walking barefoot or in low-heeled shoes usually exacerbates the pain, while walking in shoes with an increased heel height usually eases the pain. There is usually no history of trauma even though patients with blunt trauma to the dorsal midfoot may complain of very similar symptoms. On physical examination of the patient with DMICS, there is discrete tenderness along the dorsal joint lines of the affected midfoot joints but no tenderness along the dorsal aspects of the extensor tendons with dorsiflexion resistance applied at the digits. Edema is never present plantarly and minimal edema is only detected at the dorsal midfoot in the worst cases of DMICS. There is no pain with forceful manual dorsiflexion of the forefoot on the rearfoot. However, there is very significant pain with plantarflexion of the forefoot on the rearfoot. This test, the Forefoot Plantarflexion Test, is the hallmark in the physical examination of patients with DMICS is that they all have very significant pain with plantarflexion of the forefoot on the rearfoot. The Forefoot Plantarflexion Test is a remarkably sensitive indicator of the level of severity of DMICS. https://www.facebook.com/kevinakirbydpm/posts/1451668971597008 The most likely reason that manual plantarflexion of the forefoot on the rearfoot during the clinical examination causes such significant and consistent pain in patients with DMICS is that the dorsal margins of the midfoot joints have, over time, developed microfractures and/or bone edema due to the excessive compression forces within their dorsal midfoot joints (see illustration). The dorsal capsular ligaments which attach to these damaged area of dorsal midfoot joint bone will pull on these areas of damaged bone which causes pain. Again, the cause of the bone damage within the dorsal articular margins of the midfoot joints is the chronic excessive interosseous compression force (ICF) in these joints during weightbearing activities. The combination of three main forces act together on and within the foot during late midstance to cause an increase in the ICF across the dorsal joint surfaces of the midfoot (see illustration). First, the weight of the body exerts a plantarly directed force through the tibia onto the talar dome at the ankle joint. This ankle joint compression force is increased by any tension forces within the Achilles tendon, tendons of the deep posterior compartment muscles and peroneal muscle tendons. Second, due to the requirements of the gastrocnemius and soleus muscles to be active during late midstance, the Achilles tendon has large tension forces which cause a rearfoot plantarflexion moment which, in turn, has a tendency to flatten the longitudinal arch of the foot. Lastly, since the center of mass of the body is over the metatarsal heads during late midstance, ground reaction force (GRF) is at its peak on the metatarsal heads which causes a dorsiflexion moment on the forefoot. The net result of these three forces acting together is a very strong flattening force or moment on both the medial and lateral longitudinal arches of the foot. The stronger the flattening moments on the medial and lateral longitudinal arches, the greater is the ICF across the dorsal joint surfaces of the midfoot. The flattening moments on both the medial and lateral longitudinal arches are increased by such factors as increased body weight, low heeled shoes and limited ankle joint dorsiflexion. Weak plantar ligaments and weak plantar intrinsic and plantar extrinsic muscles also increase the dorsal ICF at the midfoot since these ligaments and muscles help prevent medial and lateral longitudinal arch collapse. It is the repetitive trauma at these dorsal midfoot joint surfaces with each step which causes the pain from DMICS. Treatment revolves around both reducing the inflammation to the dorsal midfoot joints and trying to eliminate the mechanical factors causing the increased flattening moments on the medial and lateral longitudinal arches. Local treatment to reduce inflammation may include relacing shoes or choosing shoes that do not cross dorsally over the affected area of the dorsal midfoot. In addition, icing and non-steroidal anti-inflammatory drugs and even cortisone injections may be necessary in resistant cases. The worst cases are treated initially with cam-walker brace boot walkers for 3-6 weeks. Mechanical treatment involves, first of all, having the patient stretch their Achilles tendons and either adding a heel lift to their shoes or getting them into a slightly higher heeled shoe. Most helpful is to prevent the medial and lateral longitudinal arches from collapsing during gait as much as possible with either padding, strapping or prescription foot orthoses. The foot orthoses must be stiff enough to support the medial and lateral longitudinal arches and should be well contoured to the foot. I find that if the initial treatment of the patient with temporary insoles or padding is helpful, the patient is very happy to proceed further with the more corrective and much more beneficial prescription foot orthoses since DMICS can be quite a painful and debilitating condition. Proper conservative treatment, outlined above, is routinely very effective. [Excerpted with permission from: Kirby KA.: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, AZ, 1997, pp. 165-166.]

21.01.2022 Posterior View of Van Langelaan's 1983 Cadaver Foot-Lower Leg Preparation In Van Langelaan's landmark 1983 PhD thesis research, he measured the motions of the a...nkle joint, subtalar joint and midtarsal joints in 10 cadaver foot-lower leg preparations using x-ray photogrammetry. He was the first to discover that the midtarsal joint does not have two fixed, constant-location axes, the oblique and longitudinal midtarsal joint. Rather, he discovered that the calcaneo-cuboid joint and talo-navicular joints are much more complex, each having multiple joint axes that are arranged in "bundles" around each specific joint center. In other words, 34 years ago, Van Langelaan busted the myth of the two fixed-axis midtarsal joint that is still being taught to this day to podiatry students around the world (Van Langelaan EJ: A kinematical analysis of the tarsal joints: An x-ray photogrammetric study. Acta Orthop. Scand., 54:Suppl. 204, 135-229, 1983). In the video below, a posterior-medial view of one of Van Langelaan's osteo-ligamentous foot-lower leg preparations is shown being driven by a a mechanical apparatus with a motor attached the tibia from above. With external rotation of the tibia, the subtalar joint supinates and inversion rotation of the forefoot relative to the ground occurs. With internal tibial rotation, the subtalar joint pronates and eversion rotation of the forefoot relative to the ground occurs. Note the complex, three-dimensional motions at the midtarsal joints and midfoot including the transverse plane rotation of the plantar calcaneus relative to the weightbearing surface during these rotational motions of the foot and lower extremity.

20.01.2022 Karen Burns Podiatry remains open for business. Please call 49585694 if you have any concerns about attending your appointment.Karen Burns Podiatry remains open for business. Please call 49585694 if you have any concerns about attending your appointment.

20.01.2022 Foot Orthosis Modifications for Plantar Plate Tears Tears of the plantar plates of the lesser metatarsophalangeal joints (MPJ)can be effectively treated with cu...stom foot orthoses which are specially modified to reduce the compression and tension forces on the affected plantar plate. These orthoses are designed using Tissue Stress Theory where the goal of foot orthoses are to reduce the excessive loading forces on the injured structural component of the foot. The Subtalar Joint Neutral Theory, taught by Root and colleagues for decades, and which emphasized "preventing compensations for deformities of the foot" and "trying to make the foot function in the subtalar joint neutral position", neglected to stress the importance of using forefoot extensions in orthoses and was not effective at treating plantar plate tears. Over the years of treating plantar plate tears (previously called MPJ capsulitis), I have used a number of orthosis modifications, two of which are shown below (see my illustrations below for 2nd MPJ plantar plate tears). The anterior edge of the plate can be modified to create an extended portion at the 2nd ray in order to support the 2nd metatarsal shaft distally all the way to the metatarsal neck. Alternatively, a metatarsal pad may be added to the anterior edge of the orthosis. In addition, it is very important to accommodate the affected metatarsal head with a flexible, non-compressible material such as Korex or EVA. I generally will start with 1/8" (3 mm) Korex which may be increased, or decreased, in thickness depending on the patient's symptomatic response to the forefoot accommodation. Such orthosis modifications can mean the difference between pain with each step versus no pain at all during the day for the patient suffering from plantar forefoot pain from plantar plate tears. I will combine foot orthoses with other conservative therapies such as daily plantar icing therapy, having the patient purchase soft-soled sandals for home use (Oofos sandals are my favorite), avoiding any barefoot weightbearing activities, and using digital plantarflexion taping to prevent excessive plantar plate tension forces during gait. Cortisone injections may also be administered into the soft tissues plantar to the plantar plate to reduce excessive inflammation and swelling if the patient's foot does not respond to other conservative measures after a few weeks of treatment.

19.01.2022 How to examine patients with suspected medial tibial stress syndrome/fracture and how to differentiate between them? https://t.co/TfX179Ehnr https://t.co/ej0OsWFKdb

19.01.2022 Abductory Twist: What is It and Why Does It Occur? Abductory twist is a sudden abduction motion of the foot at the time of heel-off during walking gait. Abduct...ory twist is a relatively common gait abnormality that occurs due to the external rotation motion of the pelvis above the foot during late midstance not being matched by corresponding subtalar joint supination and tibial external rotation during late midstance. As a result of this "mismatching" of transverse plane rotations of the pelvis and lower extremity during late midstance, the resultant increase in elastic strain energy occurring within the muscles, tendons and ligaments of the hip, knee and lower extremity will be resolved into this rapid medial movement of the heel at the time of heel-off. The reason why the abductory twist occurs just after the instant of heel-off is because the frictional forces between the heel of the foot and the ground are no longer present after heel-off to prevent external rotation motion of the foot relative to the ground. The best example of an abductory twist is seen in the last few steps of the left foot of this slow motion video. It is often commonly clinically seen with late midstance pronation which makes good biomechanical sense because increased subtalar joint pronation moments in late midstance will tend to result in both late midstance pronation and abductory twist.

19.01.2022 What are the clinical pearls for successfully improving the gait function and comfort of patients with severe pes plano valgus deformities with custom foot orthoses? https://t.co/Xqjnh1sTB2 https://t.co/XbuMPwYfOC

17.01.2022 In patients with surgically resected #melanoma, those with BRAF mutations who received 1 year of oral adjuvant therapy with dabrafenib and trametinib had a 53% lower risk of 3-year recurrence than those who received placebo. Learn more on NEJM Resident 360: http://nej.md/2ztREIr

17.01.2022 The Windlass and Reverse Windlass Effects of Hicks The Windlass and Reverse Windlass Effects were first described 66 years ago by John H. Hicks in his classic p...aper on the biomechanics of the plantar fascia in 1954 (Hicks JH: The mechanics of the foot. II. The plantar aponeurosis and the arch. J Anatomy. 88:24-31, 1954). Hicks noted that hallux dorsiflexion, in both live feet and cadaver feet, produced the mechanical effect of raising of the medial longitudinal arch and plantarflexing the first ray. He also found that during relaxed bipedal standing, hallux dorsiflexion produced subtalar joint supination and external rotation of the leg. Hicks called this mechanical linking of hallux dorsiflexion to first ray plantarflexion, medial longitudinal arch elevation, subtalar joint supination and external leg rotation the "Windlass Effect". Hicks described in his paper how the hallux and the plantar fascia were a mechanical analogue to a windlass winding a cable (i.e. plantar fascia) around the drum (i.e. first metatarsal head) of the windlass. Hicks also noted that a "Reverse Windlass Effect" occurred in both live and cadaver feet where the digits all plantarflexed with the application of loading force being applied onto the plantar metatarsal heads. Hicks determined that the "Reverse Windlass" was due to the plantar loading force on the metatarsal heads producing a flattening and lengthening of the longitudinal arch of the foot which, in turn, increased the tension within the plantar fascia and plantarflexion of the digits. Hicks also noted that cutting of the plantar fascia in cadaver feet eliminated both the Windlass and Reverse Windlass Effects. Podiatrists and foot-health clinicians should understand the windlass and reverse windlass effects that Hicks described 66 years ago since the plantar aponeurosis has very important biomechanical functions for the human foot during weightbearing activities. Plantar fascial ruptures and plantar fasciotomies will alter the function of the plantar fascia and cause a multitude of pathological conditions as a result of the alterations within the biomechanical function of the plantar fascia. For those who would like to further reading on the biomechanical functions of the plantar fascia, I wrote an article on the 10 functions of the plantar fascia six years ago which is listed below. https://www.podiatrytoday.com/understanding-ten-key-biomech.

17.01.2022 Ganglion Aspiration Without Anesthetic or Syringe I performed this ganglion aspiration on a 49 year-old female patient who has had a ganglion recur on and off o...ver the past five years on the dorsal aspect of her forefoot. The ganglion was about 3.0 cm x 3.0 cm in area and about 8 mm thick, filled with about 3-4 cc of fluid. In this procedure, no syringe or local anesthetic is necessary. After sterile prep with a povidone-iodine solution, ethyl chloride is sprayed onto the ganglion for about 5-6 seconds to temporarily numb the skin over the ganglion. Then an 18-gauge hypoderemic needle is used to puncture the lateral aspect of the gangion. The ganglionic fluid is then fully expressed out of the ganglion using manual pressure on the top and sides of the ganglion. A sterile 2x2" gauze and 3" coban wrap is then used for a compression dressing which is kept on for 24 hours. Total procedure time for this alternative ganglion aspiration technique is about 5 minutes. I have used this ganglion aspiration technique now for the past 25 years and have never had any problems with the procedure. Patients are pain-free the next day after the procedure and are also able to perform full activities the day following the procedure.

15.01.2022 "It's like Netflix for medical lectures!" This is the first time complex medical conditions are explained in an easy to understand way. Perfect for Medical & Nu...rsing Students. But even those already working as a Nurse or Doctor can greatly benefit from these lectures! We have to admit, with over 800+ videos on basic and clinical medicine, it's hard to fight the urge to binge watch. We get it. That's why we offer our members multiple playback speeds. Tap [SIGN UP] to receive lifetime access and save up to 80%

15.01.2022 Its not just a heel problem: "This study found widespread pressure pain hypersensitivity over both nerve trunks and musculoskeletal structures in individuals with unilateral chronic plantar heel pain, suggesting the presence of a central altered central nociceptive pain processing."

15.01.2022 What is the optimal custom foot orthosis design for treating runners with medial tibial stress syndrome.....and why? https://t.co/o1suVnJxTG https://t.co/wp5oAdtGlT

15.01.2022 Low-Dye Strapping for Plantar Fasciitis and Plantar Arch Pain Here I am demonstrating the proper technique for application of Low-Dye strapping. Typical low-Dye... strapping involves using 1" and 2" cloth adhesive tape to apply a tension-load-bearing strapping system to the plantar longitudinal arch of the foot. Low-Dye strapping, by preventing excessive longitudinal arch flattening, reduces the tension force within the plantar fascia and other plantar tension load-bearing structures of the plantar foot, such as the plantar intrinsic muscles and plantar ligaments. Low-Dye strapping may be used in conjunction with custom foot orthoses to decrease the pain with weightbearing activities within the tension load-bearing structures of the plantar foot. The 1" and 2" cloth adhesive tape I like to use for Low-Dye strapping is Johnson & Johnson Zonas porous tape. https://www.amazon.com/Johnson-JJ5104-Zonas-P//ref=sr_1_4 https://www.amazon.com/Johnson-First-Aid-Zona//ref=sr_1_2 Ideally, the skin of the plantar foot should be cleaned with isopropyl alcohol before taping to increase tape adhesion. In addition, a "pre-tape spray" containing a skin adherent greatly helps the tape stay adhered tightly to the skin for a longer period of time. https://www.amazon.com/Cramer-Taping-Spray-A//ref=sr_1_10 Alternatively, K-tape, a more expensive alternative to cloth adhesive tape, which is more compliant (i.e. more stretchy) than cloth adhesive tape, can also be used in the same fashion and is generally easier for the patient to apply. However, K-tape will generally produce a lesser effect on reducing the tension load on the plantar fascia and other tension load-bearing structures of the longitudinal arch than with cloth adhesive tape (Kirby KA: Longitudinal arch load-sharing system of the foot. Revista Española de Podología, 28(2), 2017) https://www.sciencedirect.com//artic/pii/S0210123817300087

14.01.2022 Does Modern Shoegear Cause Permanent Deformation of Digits? A very interesting article was published four years ago on the morphological differences between the... feet of shod and unshod populations of runners (Shu Y, Mei Q, Fernandez J, Li Z, Feng N, Gu Y. Foot morphological difference between habitually shod and unshod runners. PloS one. 2015 Jul 6;10(7):e0131385) https://journals.plos.org/plosone/article/file In this study, 168 habitually unshod runners (Indians) and 196 shod runners (Chinese) participated in a foot scanning test using the easy-foot-scan (a three-dimensional foot scanning system) to obtain 3D foot surface data and 2D footprint imaging. Foot length, foot width, hallux angle and minimal distance from hallux to second toe were calculated to analyze foot morphological differences. This study found that significant differences exist between groups (shod Chinese and unshod Indians) for foot length (female p = 0.001), width (female p = 0.001), hallux angle (male and female p = 0.001) and the minimal distance (male and female p = 0.001) from hallux to second toe. The measured distance between the hallux and 2nd digit in the barefoot versus the shod population was 17 mm greater in males and 14 mm greater in females, meaning that the unshod population had much greater separation of their hallux and 2nd digit than the shod population (see illustration from paper below). Some footwear, specifically shoes which have a more narrow toe-box (i.e. more narrow from medial to lateral), such as dress shoes for women, likely create a deforming force on the digits when being worn, which, over time, may create plastic deformation of the restraining ligaments of the metatarsophalangeal joints and digits. These shoes create, over time, a deforming force of the digits within the transverse plane, pushing the medial digits laterally and the lateral digits medially toward the central digits so that, when standing, the digits are all resting closer to each other, or touching the other digits. This chronically-shod toe pattern, with no separation between the digits, is commonly seen in older individuals who have worn snug shoes (especially women) all their lives. However, individuals who habitually go barefoot or wear non-restricting sandals, generally have a larger separation between all the digits as they age. Therefore, modern shoes, especially women's slip-on dress shoes, which must be tight in the toes to just stay on the foot while walking, likely create transverse plane deformations of the digits over time. Of course, hallux abducto valgus/bunion deformities and 4th and 5th digit adductovarus hammertoe deformities and even digital corns may be the result of these shoe habits over time. Further research will be necessary to determine whether biomechanical function of the foot is also affected by chronic use of tight shoes in runners and non-runners.

14.01.2022 Can a Plantar Plate Tear Be Repaired Non-surgically? Up until a year ago, when patients had asked me whether a plantar plate tear could be healed with conservat...ive treatment only, I had told them I could likely make their symptoms improve, but their abnormal toe position and plantar plate tear could not be fully healed to normal length without surgery. However, while researching the literature on plantar plate tear injuries a year ago, I read this rather remarkable paper by an orthopedic foot surgeon and radiologist from Augsburg, Germany, that treated and followed one of their own hospital's nurses that had a plantar plate tear through serial high-resolution MRI scans over a year's period of time. The results were very impressive. A 48-year-old female intensive care nurse at their hospital had injured her right forefoot in a water skiing accident in September 2013. She described immediate pain at the base of her second toe, followed by local swelling. She first was evaluated by the orthopedic surgeon for the first time in March 2014, 6 months after the injury had occurred.. She presented with pain on palpation over the plantar aspect of the base of the basal phalanx of her second toe on her right foot. Compared with the contralateral side, the second metatarsophalangeal joint (MPJ) was unstable with a positive dorsal drawer test. Complete dislocation of the joint was not observed during the drawer test. Swelling was also present on the dorsal aspect of the second MPJ joint. The patient described no history of a previous episode of forefoot pain before the water skiing accident. High-resolution MRI scans at the first evaluation revealed a rupture of the plantar plate of the second MPJ joint (see serial MRI images below). After a discussion of the treatment options, the patient decided on a nonoperative treatment plan for the pathology in her right foot. A therapeutic regimen was initiated consisting of taping the second toe in 10 degrees of plantarflexion and a forefoot unloading shoe with a selective cushioning insole for the second MPJ joint. This insole could accommodate a slightly plantarflexed second toe by an additional modification that reduced its height compared with the areas for contact with the other toes (Darco shoe). The patient was also instructed in the taping technique, and she was asked to wear the shoe full time. Digital plantarflexion taping was used for 6 months. Using this taping, the patient was able to work in her normal job. She was reevaluated clinically at 3, 6, 8, and 12 months. Follow-up MRI scans were also performed at 3, 8, and 12 months (i.e. 4 sets of MRI scans total) after her first clinical presentation. All MRI scans were performed and read by the same musculoskeletal radiologist and all clinical examinations were performed by the same orthopedic surgeon. When presenting at 3 months after the initiation of treatment, the patient reported only a mild overall improvement in her symptoms. She could walk with the forefoot unloading shoe but felt unable to walk with standard footwear. The clinical evaluation revealed that the joint was more stable and less swollen and the plantar plate was less painful on palpation compared with at the initial examination. Also, the toe was noted have returned to a physiologic position compared with the slight hammer toe and about 10-15 degrees of dorsiflexion at the beginning of treatment. At the evaluation 6 months after the initiation of treatment, she reported less pain and her clinical symptoms were similar to those she had described at the 3-month follow-up visit, although she described further reduced tenderness over the plantar aspect of the base of the proximal phalanx of the second toe. The patient also reported that she had worn both shoe and tape consistently. She was able to work full time during the entire 6-month treatment period. For the second 6 months, the treatment was reduced to a stiff-soled shoe with special insoles offloading the second MTP joint, and no further taping was recommended. The patient was instructed to continue to avoid recreational sports activities. No MRI was taken at the 6-month follow-up point. At 8 months after the initiation of nonoperative treatment, the patient reported having occasional, slight pain in the area of the base of the second toe but was pain-free otherwise. Gait examination revealed a non-antalgic gait with normal stride length with the second digit being stable on dorsal drawer testing and not painful on palpation. The toe showed a physiologic alignment, and the paper-pull out test for the previously injured second toe was normal. Additional follow-up MRI scans revealed further improvement in the structural integrity of the plantar plate of the second MTP joint. At this point, moreover, the patient was allowed to resume sports activities and to wear normal shoes. At the final follow-up examination, 12 months after initiation of the nonoperative treatment protocol, the patient reported that she was comfortably participating in sports at a level comparable to that of her pre-injured state, approximately 18 months earlier. She experienced no more pain in the ball of her foot, and the results of the clinical examination were comparable with those observed for the contralateral, uninjured foot, neither of which displayed edema, pain, or joint instability. A final follow-up MRI scan was obtained, which revealed further evidence of repair of the plantar plate. In conclusion, this patient initially presented with pain at the plantar base of the basal phalanx, local edema, a positive dorsal drawer sign, and a mild hammer toe deformity, all typical symptoms with a high suspicion of a tear of the plantar plate, which was also strongly suggested by the MRI findings. The clinical and MRI follow-up for a 12-month period showed that her plantar plate rupture healed clinically and on MRI, with full function restored. One interesting aspect in this case report was the delayed onset of therapy (6 months after the initial accident), which suggests a satisfactory result can be achieved even after a period of chronic rupture. Certainly, after reading this very interesting case study, I am more optimistic about using extended periods of conservative care for my patients with confirmed plantar plate tears. The MRI scans in this case study which show the healing of the plantar plate over time is a first reported within the medical literature and offers convincing support for the idea that plantar plate tears may be able to be healed, with no further digital deformity, no pain, and a full restoration in activities, in some individuals. Certainly, further study with larger populations are necessary to see how this type of protocol would work for healing plantar plate tears in a wider range of individuals. At this time, however, I am much more confident to treat these injuries over 12 months or longer before surgical repair of the plantar plate is being recommended for patients with painful plantar plate tears. (Jordan M, Thomas M, Fischer W: Nonoperative treatment of a lesser toe plantar plate tear with serial MRI follow-up: a case report. J Foot Ankle Surgery. 56(4):857-861, 2017).

13.01.2022 How Does the Plantar Fascia Help Increase Longitudinal Arch Stiffness During Midstance and Propulsion? John Hicks, an orthopedic surgeon from Birmingham, UK, wa...s the first scientist to write extensively on the biomechanical functions of the plantar fascia (i.e. central component of the plantar aponeurosis) over 65 years ago (Hicks JH: The mechanics of the foot. II. The plantar aponeurosis and the arch. J Anatomy. 88:24-31, 1954). He noted that, in both live feet and in non-living cadaver feet, if hallux dorsiflexion occurred, that longitudinal arch raising would occur, which he called the "Windlass Effect". Hicks also described the "Reverse Windlass Effect" where longitudinal arch lowering during weightbearing would cause the digits to plantarflex. In the summary of his experimental work on the plantar fascia, HIcks noted three key points: "1. The plantar aponeurosis at its distal end is attached through the plantar pads of the metatarsophalangeal joints to the proximal phalanges. The attachment is mechanically very strong. 2. When the toes are extended they pull the plantar pads and hence the aponeurosis forward around the heads of the metatarsals, like a cable being wound on to a windlass. The arch is caused to rise because the distance between the metatarsal heads and the calcaneum is thereby shortened. 3. The toes are forced into an extended position in toe-standing and walking by the action of body weight, and the arch is caused to rise by this ligamentous mechanism without the direct action of any muscle." This classic paper by HIcks is a must-read for anyone with an interest in foot and lower extremity biomechanics (Hicks JH, 1954). Since the time of HIcks, other podiatrists have noted the importance of the function of the plantar fascia during walking. Howard Dananberg, DPM, in his classic papers on functional hallux limitus, discussed the windlass effect and plantar fascial function when describing three "auto-supportive mechanisms" in the human foot during walking including: 1) Calcaneocuboid joint locking, 2) Truss and locking wedge effect, and 3) Windlass effect (Dananberg HJ: Gait style as an etiology to chronic postural pain. Part I. Functional hallux limitus. JAPMA, 83:433-441, 1993). In his description of the calcaneocuboid joint locking mechanism of Bosjen-Moller from 1979 (Bojsen-Møller , F: Calcaneo-cuboid joint and stability of the longitudinal arch of the foot at high and low gear push off. J Anat, 129:165, 1979), Dananberg noted the following important characteristics of the plantar fascia: "The plantar aponeurosis runs from the inferior surface of the calcaneus to the bases of the proximal phalanges of the toes. It is thickest at the first toe and progressively thinner toward the fifth toe. The tension that develops within this fascia dictates the stability it provides to the foot. This action is that of a tension band. The plantar aponeurosis can be likened to a string on a bow (bow and arrow). When sufficient tension is evident within the string, the bow maintains its arched shape. When cut, the bow will immediately straighten. The mechanism of the developing adequate tension within the aponeurosis at the correct time is essential for proper foot function. If the tension is produced too soon, the foot will not provide proper mobility at impact. If the tension is produced too late, the foot will not have adequate stability to handle the increasing force applied to it during the mid-to-late phase of single-limb support" (Dananberg, 1993). In 2017, I also published a paper on longitudinal arch biomechanics and plantar fascia function in the Spanish podiatry journal, Revista Española de Podología, My paper on the Longitudinal Arch Load-Sharing System (LALSS) of the Foot described how four sets of tension load-bearing elements in the plantar foot all worked together to stiffen the longitudinal arch (Kirby KA: Longitudinal arch load-sharing system of the foot. Revista Española de Podología, 28(2), 2017). From superficial to deep (i.e more plantar to more dorsal) these four sets of tension load-bearing elements are the 1) plantar fascia, 2) plantar intrinsic muscles, 3) deep posterior compartment muscles (i.e. posterior tibial, flexor digitorum longus and flexor hallucis longus) and peroneus longus muscle, and 4) the plantar ligaments. The passive elements of the LALSS, the plantar fascia and plantar ligaments, work independent of the central nervous system (CNS). The active elements of the LALSS, the plantar extrinsic and plantar intrinsic muscles, are actively controlled by the CNS (Kirby, 2017). The passive elements of the LALSS, the plantar ligaments and plantar fascia, provide a baseline level of longitudinal arch stiffness which requires no metabolic cost to the individual since tension within the plantar ligaments and plantar fascia increases without muscular effort as the longitudinal arch flattens and lengthens during weightbearing activities. The passive elements of the LALSS are assisted by the active elements of the LALSS, the extrinsic muscles of the plantar arch and plantar intrinsic muscles, which are under direct control of the CNS. The extrinsic muscles of the plantar arch and plantar intrinsic muscles function to increase the stiffness of the longitudinal arch above the baseline longitudinal arch stiffness provided by the passive tension within the plantar fascia and plantar ligaments during weightbearing activities. Together both the passive and active elements of the LALSS work synergistically to modulate the magnitude of longitudinal arch stiffness depending on the nature, intensity and direction of the weightbearing activity chosen by the individual (Kirby, 2017). In other words, all four sets of these tension load-bearing elements work together with each other to increase the stiffness of the longitudinal arch not only during midstance, but also during propulsion (see illustration below). Contrary to claims from recent research, there is no evidence that the plantar intrinsic muscles and deep posterior compartment and peroneus longus provide any more increase in longitudinal arch stiffness than that of the plantar fascia and plantar ligaments. In fact, each one of these tension load-bearing elements assist the other three elements which make up the LALSS to allow normal walking gait to occur, which specifically includes longitudinal arch stiffness during the second half of the stance phase of walking gait (Kirby, 2017). In fact, finite element modelling studies of the plantar fascia, longitudinal arch and windlass effect have demonstrated that plantar fascia tension increases 66% due to the windlass effect during propulsion which, by itself, increasea the longitudinal arch stiffness during propulsion (Chen YN, Chang CW, Li CT, Chang CH, Lin CF. Finite element analysis of plantar fascia during walking: a quasi-static simulation. Foot & ankle international. 2015 Jan;36(1):90-97). Finite element modeling is likely the only current method, other than invasive testing of live subjects with implanted strain gauges, to experimentally determine the relative contributions of the plantar fascia, plantar ligaments and plantar intrinsic and extrinsic muscles to increasing longitudinal arch stiffness. The list of references which follows is only a partial list of other finite element references that demonstrate that the plantar fascia and plantar ligaments together share considerable tension loads to maintain longitudinal arch stiffness during weightbearing activities of the foot, further supporting the concepts of the LALSS of the foot. Cheung JT, An KN, Zhang M. Consequences of partial and total plantar fascia release: a finite element study. Foot & ankle international. 2006 Feb;27(2):125-32. Wu L. Nonlinear finite element analysis for musculoskeletal biomechanics of medial and lateral plantar longitudinal arch of Virtual Chinese Human after plantar ligamentous structure failures. Clinical Biomechanics. 2007 Feb 1;22(2):221-9. Cheng HY, Lin CL, Wang HW, Chou SW. Finite element analysis of plantar fascia under stretchthe relative contribution of windlass mechanism and Achilles tendon force. Journal of biomechanics. 2008 Jan 1;41(9):1937-44. Cheng HY, Lin CL, Chou SW, Wang HW. Nonlinear finite element analysis of the plantar fascia due to the windlass mechanism. Foot & ankle international. 2008 Aug;29(8):845-51. Tao K, Ji WT, Wang DM, Wang CT, Wang X. Relative contributions of plantar fascia and ligaments on the arch static stability: a finite element study. Biomedical Engineering/Biomedizinische Technik. 2010 Oct 1;55(5):265-71. Liang J, Yang Y, Yu G, Niu W, Wang Y. Deformation and stress distribution of the human foot after plantar ligaments release: A cadaveric study and finite element analysis. Science China Life Sciences. 2011 Mar 1;54(3):267-71. Chen YN, Chang CW, Li CT, Chang CH, Lin CF. Finite element analysis of plantar fascia during walking: a quasi-static simulation. Foot & ankle international. 2015 Jan;36(1):90-7.

13.01.2022 Verrucae Plantaris Needling Technique in 17 Year-old Male Patient Demonstrated here is the Falknor needling technique for eradication of verruca plantaris lesio...ns. American podiatrist, Gordon Falknor, DPM, first described this procedure 51 years ago, in February 1969 (Falknor GW: Needling-a new technique in verruca therapy: a case report. JAPA, 59:51-52, 1969). I have been using the Falknor needling technique for verrucae plantaris lesions for the past 25 years. During that time, my success rate in eradicating these lesions with this technique is approximately 80%. No infections or other untoward complications have ever been noted using this procedure. In my performance of the Falknor needling technique in this 17 year-old male patient, I used 3.0 ml of local anesthetic to infiltrate deep to the lesion with a 5.0 cc syringe and 25 gauge needle. About 5 seconds of ethyl chloride spray was used prior to the needle stick at the needle injection site to temporarily numb the area of injection. I rarely use a posterior tibial nerve block when performing these plantar injections since there is only mild pain from plantar injection after transient skin freezing with the ethyl chloride spray. After local anesthetic administation, the area of the verrucae is prepped with a povidone-iodine solution and the area is draped with a sterile fenestrated drape. Next, using a 25 gauge needle, the verrucae plantaris lesion is punctured through the full thickness of the epidermis and dermis until bleeding occurs. About 100 needle punctures were used in this lesion. For larger verruca lesions, more needle punctures should be used. For smaller verruca lesions, fewer needle punctures will be necessary. The depth of penetration of the needle needs to be such that the tip of the needle passes through the dermis and into the subcutaneous fat so that perceptible bleeding occurs at the needle puncture site. The clinician will initially feel needle resistance once the needle first pushes through the epidermis and dermis. Once the subcutaneous fat is entered with the needle tip, there will be a sudden decrease in resistance to needle advancement which is where needle advancement into the skin should be stopped. There is no need to go deeper than the subcutaneous fat with needle puncture to stimulate the immune response required to cause eradication of the verruca lesion using the Falknor needling procedure. The basic idea is to drive the verruca virus into the subcutaneous fat and blood stream of the patient so that the patient's immune system will "recognize" the virus, stimulate an immune response, and rid the body of the verruca lesion over time. The Falknor's needling technique is a classic example of an auto-innoculation procedure which has been used for years within the medical profession. The Falknor's needling technique is especially effective for mosaic verrucae since only a few of the larger lesions (i.e. "mother lesions") need to be needled to have all of the verrucae lesions of the mosaic verrucae to be eradicated from the plantar foot generally with 3-4 weeks of the needling procedure. Using the Falknor needling technique on these hard-to-heal mosaic verrucae will make you a "hero" in the patient's eyes since the clinical results are, simply, quite amazing. Simple bandaging of the needling site is done with sterile gauze and adhesive wrap (i.e. Coban). The patient can remove the dressing 2-3 hours after the procedure, wash the needling site with soap and water, and then apply a bandaid to the area. Normal weightbeaing activities can be resumed the next day with the bandaid on the foot for one to two days. The Falknor needling technique is my favorite verrucae eradication procedure since it works better than any others I have used over the past 35 years of practice, takes only about 20 minutes of time to accomplish in my office (including injection, prepping, draping and bandaging) and causes a minimum of post-procedure pain. For example, the children I have performed this procedure on are running and playing soccer the next day on their operated foot with a minimum of pain. All podiatrists should learn to use this procedure for the good of their patients and their practices.

13.01.2022 Gait Characteristics of Cavus Feet with Laterally Deviated Subtalar Joint Axes Feet with pes cavus deformity, more often than not, have lateral deviation of the... subtalar joint (STJ) axis. This lateral deviation of the STJ axis creates excessive external STJ supination moments which can be seen during gait as excessive supination of the foot in this video. Since the medial calcaneal tubercle is so far medial to the STJ axis during heel contact in this foot, this medial positioning of the plantar heel in this patient with cavus feet creates excessively large magnitudes of external STJ supination moment generated from ground reaction force (GRF) acting on the plantar calcaneus during the contact phase of walking gait. These large magnitudes of external STJ supination moment at ground contact of the calcaneus in these feet cause the STJ to rapidly supinate in the early stance phase of gait. In this individual, also note the shortened stride length which is likely due to the lateral ankle instability being caused by these excessive STJ supination moments. When the central nervous system (CNS) notes these excessive STJ supination moments during late midstance, the CNS likely does not fully activate the gastrocnemius and soleus during the late midstance phase of walking since full contractile activity of the gastrocnemius and soleus would increase the internal STJ supination moment (i.e. due to the Achilles tendon inserting well medial to the STJ axis on the posterior calcaneus) which would, in turn, cause even more lateral ankle instability and possibly an inversion ankle injury. Careful visual gait examination is the key to the optimum treatment of mechanically-based pathologies of the foot and lower extremity. Visual gait examination is a skill which should be practiced daily by podiatrists and other foot-health professionals in their clinics.

11.01.2022 Internal Compression and Distraction Forces Within the Midfoot During normal weightbearing activities, the medial longitudinal arch (MLA) and lateral longitudin...al arch (LLA) of the foot are under constant loading forces from body weight. Standing, walking and running activities all can tend to cause the MLA and LLA foot to flatten due to the loads which the body places on it from above. In order for the MLA and LLA to resist collapse, they must be able to maintain their structural integrity under varying magnitudes of loading forces. For example, if the MLA and LLA have good structural integrity, then they should not flatten appreciably as the weight being born by it is increased. My illustration below demonstrates the medial view of the foot with the three main forces which tend to cause MLA and LLA flattening and elongation. Starting posteriorly, tension in the Achilles tendon exerts an upward pull on the posterior calcaneus. Achilles tendon tension, in combination with the downward directed body weight on the talar dome from the distal tibia, tends to cause the forefoot to be forced into the ground. The greater the Achilles tendon tension and the greater the body weight, then the harder the forefoot will be forced into the ground and the greater will be the upward directed ground reaction force (GRF) under the metatarsal heads. These three forces acting together tend to cause the forefoot to dorsiflex on the rearfoot. Since dorsiflexion is a rotational movement, then dorsiflexion force is more accurately described as a rotational quantity, or a "dorsiflexion moment". Not only does the midtarsal joint (i.e. talonavicular and calcaneocuboid joints) experience dorsiflexion moments during weightbearing activities but also do the other joints of the medial longitudinal arch. The navicular-first cuneiform joint and the first cuneiform-first metatarsal joint are also subjected to strong dorsiflexion moments (i.e. the first cuneiform attempts to dorsiflex on the navicular and the first metatarsal attempts to dorsiflex on the first cuneiform). These dorsiflexion moments on both the MLA and LLA cause each bone of the arch to attempt to rotate on its adjacent bone in the direction of MLA and LLA flattening and elongation. However, if the plantar ligaments, plantar fascia and plantar extrinsic and intrinsic muscles are all sufficiently strong and resistant to stretching, then the bones will not rotate much on each other. As a result, their articulations will remain congruent and MLA/LLA collapse will be minimized. Therefore, the net result of flattening forces acting on the MLA and LLA is that the dorsal joint surfaces are compressed and the plantar joint surfaces are distracted away from each other causing respectively, increased dorsal interosseous compression forces and increased plantar ligament tension forces (see my illustration below). The greater the flattening forces on the MLA and LLA, the greater will be the dorsal interosseous compression forces and plantar ligament tension forces. Excessive arch flattening forces caused either by increased body weight or increased activities can lead to pathological dorsal compression forces and plantar ligament tension forces along the MLA and LLA. Most podiatrists are aware that plantar fasciitis and medial arch muscular fatigue can be caused by these excessive arch flattening forces. However, many doctors are not aware that, barring traumatic injury, pain along the dorsal joint margins of the midfoot is almost always caused by the same longitudinal arch flattening forces which cause plantar symptoms. Many patients report only dorsal joint pain without plantar foot pain. In addition, many patients complain of painful dorsal bone spurs which are a direct result of excessive dorsal interosseous compression forces causing, over time, chronic irritation of the dorsal joint margins and calcium deposition. Treatment of symptoms related to excessive MLA and LLA flattening forces is the same as it has been for years, foot orthoses. Therefore, not only will plantar ligamentous strain, plantar fasciitis and abductor hallucis muscle strain all respond well to foot orthoses because the orthoses decrease the tension in these plantar structures, but also dorsal joint pain will respond to treatment with foot orthoses due to the reduction in dorsal interosseous compression forces in the bones of the midfoot that the orthoses provide. [Reprinted with permission from: Kirby KA: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, Arizona, 1997, pp. 25-26.]

11.01.2022 The Vertical Calcaneus: Is It Really "Normal"? Classic podiatric biomechanics, as taught by Dr. Merton Root and colleagues, taught that the vertical position o...f the calcaneus was a very important parameter to determine whether a foot is "normal" or not. If a patient stands in relaxed calcaneal stance position (RCSP) and is noted to have an inverted calcaneus, it was assumed that there must be some biomechanical pathology causing the calcaneus to be abnormally inverted. If a patient stands in RCSP and has an everted calcaneus, classic podiatric biomechanics taught that one should assume that some biomechanical pathology is causing the calcaneus to be abnormally everted. At the time I learned these concepts while I was a podiatry student at the California College of Podiatric Medicine from 1979 to 1983, this seemed like a very neat way to make foot biomechanics more easy and simple to understand. Unfortunately, the foot is not quite that easy or simple. The main problem with relying on calcaneal bisections to determine whether a foot is "normal" or "abnormal" is that the whole method by which the bisection of the calcaneus is clinically determined is flawed. Since we can only see skin and have to palpate through skin and fat in order to estimate the actual shape of the posterior calcaneus, there is at least a +/- 5 degree range of error in performing heel bisections with most podiatrists. I have observed this time and again in my 35+ years of teaching foot and lower extremity biomechanics to podiatry students, residents and podiatrists. The main problem which I have with the calcaneal bisection is not in its accuracy of clinical measurement but in the idea that the calcaneal bisection has some significant effect on foot biomechanics. In other words, I have a problem in using the RCSP as the basis of comparison of one foot's biomechanical makeup to another foot's biomechanical makeup. I feel that the position of the posterior surface of the calcaneus to the ground has very little biomechanical effect on the overall pronation and supination moments acting across the subtalar joint during standing. In order to analyze this concept further one must entertain the thought that the posterior surface of the calcaneus has no special biomechanical significance other than that it just so happens to be the part of the foot which is the easiest part of the calcaneus to observe, palpate and attempt to clinically bisect To better explain my reasoning, it is helpful to compare the calcaneus to balancing blocks of wood of different shapes (see Figures 1-4). First, what physical factors determines whether a block of wood will balance on a flat surface? In order for any object to balance or remain stable on a flat surface with no other external forces acting on it, the center of mass of that object must be positioned somewhere over the base of support of that object (Fig. 1). If the center of mass is positioned somewhere out of the base of support of that object, then that object will fall (i.e. rotate toward its supporting surface) because it is unstable (Fig. 2). If the same object instead now has a rounded surface which is resting on a flat surface, there is only one position in which that object will balance: it will balance only when the center of mass of that object is directly over the point of contact of that object (Fig. 3). Like the block of wood in Figure 3, the calcaneus is always resting on the rounded surface of the medial calcaneal tubercle during standing (Kirby KA, Loendorn AJ, Gregorio R: Anterior axial projection of the foot, JAPMA,, 78: 159-170, 1988.) Now, if the object (Fig. 4) not only has a rounded bottom but also has a curved or complex shape to its body (i.e. as does the calcaneus), where will it balance? To determine where it will balance should we bisect the middle of it, the bottom of it, or the top of it? Should we bisect it at all? Again the same mechanical principles which determine how a more complex-shaped object will balance should also be applied to a less complex-shaped object which which has straight and parallel sides. The complex object in Figure 4 will only balance when its center of mass is resting over its point of contact with the supporting surface. It really doesn't matter what relative position that the central, top or bottom aspects of this object has to the supporting surface. The only physical parameter that is important is the position of the center of mass in relation to the point of support of this object, since gravitational acceleration acting at the center of mass will determine the position that object will balance on the ground. Using these basic physics principles, it then seems logical that the position of the posterior surface of the calcaneus to the ground has little biomechanical effect on the foot. What is important relative to the frontal plane shape of the calcaneus is the position of the point of support of the calcaneus (i.e. the medial calcaneal tubercle) to the subtalar joint axis. I still believe the clinician can use the calcaneal bisection as a reference for the frontal plane position of the calcaneus so that motions of the calcaneus during standing and during gait may be more easily observed and measured. However, to use calcaneus verticality as a standard for determining whether feet are "normal" or "abnormal" is to ignore the basic concepts physics and thus, the basic principles of foot and lower extremty biomechanics. [Edited with permission from my October 1993 Precision Intricast Newsletter in: Kirby KA: Foot and Lower Extremity Biomechanics: A Ten Year Collection of Precision Intricast Newsletters. Precision Intricast, Inc., Payson, Arizona, 1997, pp. 37-38.]

10.01.2022 Calcaneal Bisections: What Should You Use Them For and Not Use Them For? In yesterday's posting, it was noted that calcaneal bisections are unreliable as indica...tors of foot function since when multiple examiners determine "the calcaneal bisection" they come up with multiple calcaneal bisections. It is exceedingly difficult to bisect a "lopsided pear covered by skin, fat and tendon" as many have called the attempt to clinically bisect the posterior calcaneus. That being said, placing a line on the posterior calcaneus that roughly represents a "bisection" of the calcaneus can be very helpful in the clinical examination of patients that may need custom foot orthoses. In other words, what can the "calcaneal bisection" that is drawn on the posterior calcaneus be reliably used for? 1. The calcaneal bisection may be used to reliably help determine whether the subtalar joint (STJ) is maximally pronated or not. Using Dr. Kirby's "Maximum Pronation Test", which he first described over a quarter-century ago (Kirby KA, Green DR: Evaluation and Nonoperative Management of Pes Valgus, pp. 295-327, in DeValentine, S.(ed), Foot and Ankle Disorders in Children. Churchill-Livingstone, New York, 1992), the calcaneal bisection may be used to determine how far the calcaneus everts when the peroneal muscles are activated during relaxed bipedal stance with the knees extended. The frontal plane position of the calcaneal bisection in the maximally pronated position of the STJ gives the clinician a good idea of how close the STJ functions relative to the maximally pronated position of the STJ during standing and during gait. The Maximum Pronation Test has been used in peer-reviewed research on foot orthosis function (Pascual Huerta J, Ropa Moreno JM, Kirby KA: Static response of maximally pronated and nonmaximally pronated feet to frontal plane wedging of foot orthoses. JAPMA, 99:13-19, 2009). 2. The calcaneal bisection may be used to help observe calcaneal motion during gait. Having a marker on the calcaneus helps the clinician with either visual or video analysis of gait when viewed from the posterior aspect of the patient. 3. The calcaneal bisection, when transferred to the negative plaster cast or when transferred to any other image-capture method for making foot orthoses, can be used as a reference line to order foot orthoses when communicating with the foot orthosis laboratory about how the cast of the foot should be everted or inverted to the ground when making a custom foot orthosis. 4. The calcaneal bisection may also be used to determine the total range of frontal plane motion of the calcaneus relative to the tibia during the non-weightbearing examination of STJ range of motion. This may be important in ruling out range of motion asymmetries in the STJ between the two feet of a patient in cases of congenital anomalies, subtalar joint trauma, peroneal spasm or tarsal coalition. However, on the contrary, for what purposes should the "calcaneal bisection" not be used for? It must be emphasize again that the "calcaneal bisection" represents only one clinician's opinion of the posterior shape of the calcaneus for that one day, not the "one and only calcaneal bisection". 1. The calcaneal bisection can not be used to determine the three-dimensional morphology of any part of the calcaneus. 2. The calcaneal bisection can not be used to determine the spatial location of the STJ axis relative to the ground. The spatial location of the STJ largely determines the external STJ moments acting on the foot from ground reaction force (GRF) during weightbearing activities (Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-234, 1987; Kirby KA: Rotational equilibrium across the subtalar joint axis. JAPMA, 79: 1-14, 1989; Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001). The calcaneal bisection has nothing to do with the STJ axis spatial location and, as a result, the calcaneal bisection has nothing to do with the external STJ moments that are caused by GRF acting on the plantar foot. 3. The calcaneal bisection can not be used to determine the "rearfoot varus or rearfoot valgus" since both the calcaneal bisection and STJ neutral position are measurements that have been shown to have questionable inter-examiner variability. 4. The calcaneal bisection can not be used to determine the "forefoot varus or forefoot valgus" since both the calcaneal bisection and STJ neutral position and manual positioning of the forefoot on the rearfoot are measurements that have been shown to have questionable inter-examiner variability. 5. The calcaneal bisection can not be used to predict how the foot will function during walking or running gait. 6. The calcaneal bisection can not be used to predict which pathologies an individual will develop during their lifetimes. 7. The calcaneal bisection, by itself, can not be used to determine the optimum alignment of the foot to the ground. 8. The calcaneal bisection can not be used as a structural parameter which, by itself, determine the optimum frontal plane balancing position of the foot to the ground when a custom foot orthosis is fabricated for a patient. 9. The calcaneal bisection can not be used to determine the morphology of the medial and lateral calcaneal tubercles which largely determine the location of GRF acting on the plantar calcaneus during weightbearing activities (Kirby KA, Loendorf AJ, Gregorio R: Anterior axial projection of the foot. JAPMA, 78: 159-170, 1988). 10. The relative position of the calcaneal bisection to the ground, even if it is more than 2 degrees everted, can not be used to determine whether the STJ is maximally pronated or not. Dr. Root and his disciples taught for many years that a calcaneal bisection of 2 degrees everted or more would cause the STJ to pronate to the maximally pronated STJ position. This is false. Therefore, the podiatrist and foot-health clinician should not totally stop using the calcaneal bisection during their clinical examinations of patients since the calcaneal bisection does have limited clinical uses. However, one must be careful to not assume that the calcaneal bisection is anything more than a reference line on the posterior calcaneus that can be used to help better determine calcaneal motion during gait and during clinical examination of patients and better communicate frontal plane data of the rearfoot to a orthosis laboratory for the purpose of fabricating custom foot orthoses. The calcaneal bisection is not reliable enough to be used to determine foot function or foot pathology.

09.01.2022 How Do the Plantar Fascia and Plantar Plate Cause Normal Digital Purchase Force? The plantar fascia and plantar plate form one continuous soft-tissue structure ...from the medial calcaneal tubercle, proximally, and to the base of the proximal phalanx of the lesser digits, distally. With loading of the plantar forefoot by ground reaction force (GRF), the forefoot will dorsiflex on the rearfoot which will cause a flattening and elongation of the longitudinal arch of the foot. In turn, the plantar fascia and plantar plate will come under tension forces due to this longitudinal arch elongation to resist further arch flattening and helping to stabilize the longitudinal arch from flattening further. The resultant increase in plantar fascia and plantar plate tension due to forefoot loading from GRF will also cause a metatarsophalangeal joint (MPJ) plantarflexion moment (i.e. a tendency to plantarflex the MPJ). As a result, the lesser digit proximal phalanx will plantarflex at the MPJ until the GRF under the digit is increased sufficiently to counterbalance the MPJ plantarflexion moment (see my illustration below). The result of this MPJ plantarflexion moment, therefore, is what is known as digital purchase force. Rotational equilibrium within the sagittal plane at the MPJ will only occur once the internal MPJ plantarflexion moments from the plantar fascia and plantar plate is exactly counterbalanced by the external MPJ dorsiflexion moment from GRF acting on the plantar digit (assuming no flexor tendon tension forces). In this way, the passive plantar fascia and plantar plate force which automatically develop within the human foot with forefoot loading during the latter half of the stance phase of gait will also automatically cause a digital plantarflexion moment and a digital purchase force which tends to stabilize the digit within the sagittal plane during weightbearing activities. References: Kirby KA: Understanding the biomechanics of plantar plate injuries. Podiatry Today, 30(4):30-39, 2017. Kirby KA: Longitudinal arch load-sharing system of the foot. Revista Española de Podología, 28(2), 2017. Kirby KA: New concepts in longitudinal arch biomechanics. Podiatry Today, 31(6):20-27, 2018.

09.01.2022 What role does the HBA1c level play in wound healing? https://podiatryarena.com/index.php

09.01.2022 Interesting new study: https://podiatryarena.com/index.php

09.01.2022 Standing Subtalar Joint Axis Location Technique The axis of motion of the subtalar joint (STJ) should be of special interest to all podiatrists and foot-health ...clinicians since the spatial location of the STJ axis relative to the plantar aspect of the foot largely determines the kinetics (i.e. forces and moments) of the STJ during weightbearing activities (Kirby KA: Subtalar joint axis location and rotational equilibrium theory of foot function. JAPMA, 91:465-488, 2001). I described the first technique described within the scientific literature that determined the plantar representation of the STJ axis in a paper from 33 years ago (Kirby KA: Methods for determination of positional variations in the subtalar joint axis. JAPMA, 77: 228-234, 1987). This STJ Axis Palpation Technique I invented involves the examiner using their thumb to repeatedly push on the plantar aspect of the foot to determine the points where neither pronation nor supination motion was produced (i.e. points of no rotation). Connecting these points of no rotation represents the STJ axis plantar location which, in turn, allows the clinician to determine whether their patient’s STJ axis is normally located, medially deviated from normal or laterally deviated from normal within the transverse plane One of the biggest problems with this STJ Axis Palpation Technique (SAPT) is that it is performed in a non-weightbearing setting. During the performance of the SAPT, the medial aspect of the patient’s plantar forefoot is completely unloaded since the examiner’s hand supports the plantar forefoot only under the 5th metatarsal head. The lack of plantar loading on the medial forefoot during the SAPT may lead to an underestimation of the amount of STJ axis medial deviation present in the weightbearing foot since the medial forefoot may dorsiflex (i.e. forefoot may invert) relative to the rearfoot upon standing and/or walking. In addition, the STJ axis location may also be difficult to determine in feet with excessive inverted forefoot deformities (i.e. forefoot varus/supinatus deformities) since the STJ will already be in the maximally pronated position in these feet during the SAPT. If the STJ is already maximally pronated during performance of the SAPT, when the examiner pushes lateral to the STJ axis, the STJ can pronate no further, thus making it difficult to determine the points of no rotation when performing the SAPT (Kirby KA, 1987). Approximately 15 years ago, due to these problems inherent in performing the SAPT, I began to develop a technique by which to assess the STJ axis spatial location while the patient was weightbearing, in relaxed bipedal stance. This new clinical method of STJ axis determination, which I call the Standing Subtalar Joint Axis Location Technique (SSALT), is based on my observations from using the clinical technique first described by Morris and Jones where grids of pen marks are drawn on the posterior calcaneus and anterior talar neck and then used to determine the posterior and anterior exit points of the STJ axis from the foot (Morris JL, Jones LJ: New techniques to establish the subtalar joint’s functional axis. Clin Podiatr Med Surg,11: 301, 1994). To perform the SSALT, the patient is asked to stand in relaxed bipedal stance while the examiner uses a pen to draw a rectangular box which outlines the superior-lateral quadrant of the posterior calcaneus (Fig. 1). An X is then placed in the center of that box, which represents the posterior exit point of the STJ axis. An X is also drawn centered over the dorsal aspect of the talar neck anteriorly which represents the anterior exit point of the STJ axis. Then, using a pen to represent the STJ axis, one end of the pin is placed on the X at the dorsal talar neck while the examiner then aligns the longitudinal axis of the pen so that it points, through the foot, towards the X located at the center of the superior-lateral quadrant of the posterior calcaneus. If performed accurately, the 3D location of the examiner’s pen now represents the approximate location of the STJ axis spatial location, allowing the visualization by the examiner of the STJ axis location relative to the structures of the dorsal foot. Not only does the SSALT allow the STJ axis to be represented visually in 3D space, showing both its transverse plane alignment and its sagittal plane inclination, but it also allows the STJ axis to be located in a weightbearing setting. Of course, the exact 3D location of the STJ axis cannot be determined using either the SSALT or the SAPT. However, the relatively new SSALT is a valuable method by which to clinically assess the STJ axis spatial location to help determine the best foot orthosis modifications and/or surgical procedures to treat our patient’s foot and lower extremity mechanically-based pathologies. [Reprinted with permission from the July 2017 Precision Intricast Newsletter in: Kirby KA: Foot and Lower Extremity Biomechanics V: Precision Intricast Newsletters, 2014-2018. Precision Intricast, Inc., Payson, AZ, 2018, pp. 87-88.]

08.01.2022 This is a common condition, especially seen in people with bunions.

08.01.2022 This is a post by Belinda Longhurst who is a podiatrist in the UK who has a special interest in dermatology. Some interesting information regarding melanoma. BDNG Skin Cancer Meeting 05/03/19...Continue reading

08.01.2022 Anatomy, Range of Motion and Neutral Position of the Subtalar Joint The talus and calcaneus make up the two bones of the subtalar joint (STJ), otherwise known a...s the talo-calcaneal joint. The STJ consists of three articular facets, the posterior, middle and anterior facets. The two physiologic motions of the STJ are supination and pronation. During STJ supination, the talus glides posterior-superiorly on the posterior facet of the calcaneus. During STJ pronation, the talus glides anterior-inferiorly on the posterior facet of the calcaneus. The maximally pronated position of the STJ occurs when the lateral process of the talus hits the floor of the sinus tarsi of the calcaneus. STJ supination involves posterior translation and abduction and dorsiflexion rotation of the talus relative to the calcaneus. STJ pronation involves anterior translation and adduction and plantarflexion rotation of the talus relative to the calcaneus. The neutral position of the STJ likely occurs when the posterior articulating facets of the STJ are most congruent to each other. With maximal pronation of the STJ, the anterior half of the talar posterior articulating facet separates from the posterior facet of the calcaneus. With supination of the STJ, the posterior half of the talar posterior articulating facet separates from the posterior facet of the calcaneus. Understanding the three-dimensional rotations and translations of the talus relative to the calcaneus is the key to understanding STJ biomechanics, including the functional significance of the STJ maximally pronated position, neutral position and STJ rotational stability during weightbearing activities.

05.01.2022 Is Plantar Fascia Tension Force High Both in Late Midstance and Early Propulsion? One of the classic, and in my opinion, best research articles on plantar fas...cia tension during walking gait came from a group of biomechanics researchers at Penn State Biomechanics Laboratory led by Ahmet Erdemir from 16 years ago (Erdimir A, Hamel AJ, Fauth AR, Piazza SJ, Sharkey NA: Dynamic loading of the plantar aponeurosis in walking. JBJS, 86A:546-552, 2004). The researchers used seven fresh-frozen cadaver foot and leg preparations which were thawed to room temperature and then mounted the preparations into a "dead-man walking machine" or "dynamic gait simulator"/ Their dynamic gait simulator used servomotors attached to all the extrinsic muscle tendons of the foot so that the cadaver foot-leg could walk over the ground surface. Plantar fascial tension was measured in the cadaver specimens using 0.5 mm fiber-optic cable embedded within plantar fascia which was then calibrated, after the cadaver walking experiment was performed on the cadaver specimens, in a materials testing device (see photo and illustrations from paper below). The researchers found that the tension within the plantar fascia was low in early stance phase and peaked just after heel-off as the windlass function of the plantar fascia was engaged with hallux dorsiflexion. The plantar fascia tension gradually increased during midstance and very early propulsion to peak at a maximum force of 0.96 times body weight. In addition, Achilles tendon tension force was found to be an effective predictor of plantar fascial tension (r = 0.76). Note from the plantar fascia tension force graphs below that the plantar fascia still has relatively high tension forces during early propulsion and late midstance, indicating that its ability to create stiffness within the longitudinal arch is very good during these phases of gait. The notion that the plantar fascia and windlass are only minor contributors to longitudinal arch stiffness is not supported by this unique and excellent experimental study which directly measured plantar fascia tension in cadaver feet "walking" in Penn State Biomechanics Lab's brilliant dynamic gait simulator. https://www.researchgate.net//Dynamic-Loading-of-the-Plant

05.01.2022 Fixtoe Device for Plantar Plate Tears A couple of Spanish podiatrists, David Lucas and Fran Monzo, have invented and patented a device made for treating plantar... plate tears, including the floating toes and plantar pain metatarsophalangeal joint pain associated with this condition. They call their device the Fixtoe and they were kind enough to send me a few of these devices to try on my own patients. I have had a few patients use the Fixtoe and they tend to like it. This device acts very similarly to the digital plantarflexion technique by using Velcro straps that can be adjusted to hold the affected digit in a non-dorsiflexed position. The plantar straps can also be positioned to reduce some of the ground reaction forces under the injured plantar plate. Here is their website. https://fix-toe.com/en/home/

04.01.2022 Demonstration of Neutral Suspension Negative Casting Technique The neutral suspension casting technique was first described by Root et al as a method to obtain ...a three-dimensional impression (i.e. negative cast) of the plantar aspect of a patient's foot. The foot is held with the subtalar joint neutral and with the lateral column of the foot dorsiflexed against resistance (Root ML, Weed JH, Orien WP: Neutral Position Casting Techniques, Clinical Biomechanics Corp., Los Angeles, 1971). The resulting negative cast, made from two 5" x 30" extra-fast setting plaster splints, is then used by the custom-foot orthosis laboratory to make three-dimensional positive casts of the patient's foot by pouring plaster into the negative casts. More recently, most custom foot orthosis laboratories are now scanning the inside of the casts to create a three-dimensional digital file from which custom foot orthosis may be fabricated. I do not cast every patient in exactly the same way shown in this video. Rather, I may use slight positional variations within the joints of the foot during negative casting for some patients in order to alter the three-dimensional morphology of the plantar foot. These variations in negative casting technique allow the treating clinician to slightly vary the three-dimensional shape of the negative cast from one patient to another in order to optimize the biomechanical function of custom foot orthoses for their patients.

03.01.2022 Anterior Displacement of Plantar Fat Pad in Forefoot with Digital Deformities-Another Cause of Thinning of the Plantar Fat Pad An excellent study on the cause ...of thin fat pads plantar to the metatarsal heads in the forefoot was performed by Bus et al in 2004. Bus et al measured plantar metatarsal fat pad thickness in 13 diabetic neuropathic (DN) individuals with digital deformity, in 13 DN individuals without digital deformity and in 13 controls without digital deformity. High resolution sagittal plane MRI images were taken of the subjects to assess plantar forefoot fat pad thickness. Fat pad thickness plantar to the metatarsal heads was significantly decreased only in subjects with digital deformity. Plantar metatarsal head fat pad thickness was not decreased in subjects without digital deformity, whether they had DN or not. The authors concluded that their study showed a distal displacement and subsequent thinning of the sub-metatarsal head fat pads in neuropathic diabetic patients with toe deformity and suggests that, as a result, the capacity of the tissue in this region to reduce focal plantar pressure is severely compromised. They also suggested that the combination of DN along with digital deformity likely increases the risk of plantar forefoot ulceration due to this anterior migration of the plantar forefoot fat pad in these patients (Bus SA, Maas M, Cavanagh PR, Michels RP, Levi M. Plantar fat-pad displacement in neuropathic diabetic patients with toe deformity: a magnetic resonance imaging study. Diabetes Care, 27(10):2376-2381, 2004).

03.01.2022 #TuesdayTips #Podiatry #footwear

01.01.2022 Never underestimate the power of a good pair of shoes!

01.01.2022 Some babies with clubfooot have had to have their casting treatment paused due to COVID-19. This video, produced in partnership with Global Clubfoot Initiative shows simple movements and exercises that help to keep the feet moving and mobile.