Changes in gait associated with acute stage II posterior tibial tendon dysfunction

The purpose of this study was to examine differences in gait mechanics between patients with acute stage II PTTD and healthy volunteers. Hindfoot and midfoot kinematics, plantar foot pressures and electromyographic (EMG) activity of the posterior tibialis, gastrocnemius, anterior tibialis and the peroneals were measured in five patients with acute stage II PTTD. Kinematics and kinetics were compared to a database of 20 healthy volunteers. EMG and plantar pressure data were obtained from five healthy volunteers. Hindfoot moments and powers were also calculated. The center of pressure excursion index (CPEI) was calculated from the plantar pressures. Significant differences were observed between the two groups, which confirmed clinical observations. Limited hindfoot eversion and increased midfoot external rotation occurred during the first and third rockers. The EMG data suggested that tendon dysfunction in the posterior tibialis is associated with compensatory activity, not only in its antagonists (the peroneals), but also in the anterior tibialis and the gastrocnemius. These data suggest that non-operative treatment of patients with PTTD should consider minimizing the activity of the posterior tibialis as well as the peroneals, the anterior tibialis and the gastrocnemius.

Relationship between femoral anteversion and osteoarthritis of the hip

The purpose of this study was to establish a relationship between the magnitude of femoral anteversion and osteoarthritis of the hip. Sixteen osteoarthritic subjects were compared with 18 control subjects by an improved computed tomography (CT) scanning technique. Femoral anteversion was accurately determined with little radiation exposure. There was no significant difference in femoral anteversion between arthritic subjects and a "normal" control population. There was no significant difference in femoral anteversion between the involved and the uninvolved hips of these subjects with osteoarthritis. These results suggest that performing a derotational femoral osteotomy to prevent osteoarthritis is not indicated. The cause of primary osteoarthritis is multifactorial and does not depend solely on preexistence of higher femoral anteversion.

Mechanical behavior of the Lisfranc and dorsal cuneometatarsal ligaments: in vitro biomechanical study

OBJECTIVES

To define the anatomy and mechanical properties of two ligaments stabilizing the medial tarsometatarsal joints: the Lisfranc ligament and the dorsal cuneometatarsal ligament.

DESIGN

Cadaveric study in normal feet.

SETTING

Biomechanics laboratory.

PATIENTS OR PARTICIPANTS

Twelve fresh-frozen cadaveric feet were studied.

INTERVENTION

The Lisfranc and dorsal cuneometatarsal ligaments were dissected, dimensions measured, and material properties determined with a servohydraulic MTS machine on bone-ligament-bone preparations.

MAIN OUTCOME MEASUREMENTS

Stiffness, strain, stress, modulus, failure load, ligament length, width, thickness, and cross-sectional area were determined.

RESULTS

Dorsal ligament stiffness was 66.3+/-18.3 newtons per millimeter and the Lisfranc ligament stiffness was 189.7+/-57.2 newtons per millimeter. The failure load of the dorsal ligament averaged 150.7+/-33.1 newtons and for the Lisfranc ligament, 368.8+/-126.8 newtons.

CONCLUSIONS

The stiffness and load to failure of the dorsal cuneometatarsal ligament were much higher than anticipated, which indicates that it contributes significantly to stabilizing the second metatarsal to the first cuneiform.

Calcaneocuboid distraction arthrodesis for posterior tibial tendon dysfunction and flatfoot: a cadaveric study

Nine fresh-frozen foot specimens were studied to determine the mechanical behavior of the foot using calcaneocuboid distraction arthrodesis, an operation designed for treatment of posterior tibial tendon dysfunction with flatfoot deformity. Flatfoot deformity was created in cadaveric specimens, and to simulate toe-off phase of gait, loads were applied to the plantar surface of the foot and six tendons. Three-dimensional tarsal bone positions were determined with a magnetic tracking system. With ligament sectioning, flatfoot deformity was observed and average arch height decreased 53 +/- 3.5 mm. Height arch increased after calcaneocuboid distraction arthrodesis an average of 3.2 +/- 3.6 mm and was less than normal arch at an average of 2.1 +/- 2.4 mm. Metatarsotalar alignment compared with flatfoot improved after calcaneocuboid distraction arthrodesis in adduction and inversion to the extent that these were not significantly different from intact foot positions. Calcaneotalar position improved after calcaneocuboid distraction arthrodesis in adduction and inversion. Calcaneocuboid alignment compared with flatfoot improved after calcaneocuboid distraction arthrodesis in adduction, plantar flexion, and eversion, but compared with an intact foot was overcorrected in all three planes of motion. Arch alignment in simulated toe-off phase of gait in cadaveric feet was improved significantly with calcaneocuboid distraction arthrodesis but was not reduced anatomically.

The manual stress test may not be sufficient to differentiate ankle ligament injuries

OBJECTIVE

To assess the accuracy of stress tests (anterior drawer, talar tilt) in the diagnosis of lateral ligament injuries.Design. Stress tests were performed in vitro, and rotation and displacement of the calcaneus relative to the tibia were measured.

BACKGROUND

Stress tests are commonly used to diagnose ankle injuries. However, it is controversial as to whether stress tests can accurately differentiate between isolated anterior talofibular ligament injuries and combined anterior talofibular and calcaneofibular ligament injuries.

METHODS

Stress tests were performed in vitro under three conditions with both ligaments intact, after sectioning the anterior talofibular ligament, and after sectioning the anterior talofibular and calcaneofibular ligament. Motion of the calcaneus relative to the tibia was measured in neutral and in 20 degrees of plantarflexion at the ankle.

RESULTS

There were statistically significant differences among cadavers, examiners and positions. There was a difference between isolated anterior talofibular ligament sectioning and combined anterior talofibular and calcaneofibular ligament sectioning in lateral tilt but not in anterior displacement. In contrast, a difference was found between intact and anterior talofibular ligament sectioned specimens in anterior displacement but not in lateral tilt. However the differences were not great enough to differentiate between the two conditions.

CONCLUSIONS

Each of the stress tests provides reasonable hindfoot displacement but neither is sufficient for accurate diagnosis of specific ligament involvement due to the large amount of individual variation.

RELEVANCE

Many clinicians rely on stress tests to diagnose lateral ligament injuries and to assess the extent of anatomic disruption. This in vitro study has demonstrated poor correlation between clinical stress tests and the degree of ligamentous disruption.

Role of medical capsule and transverse metatarsal ligament in hallux valgus deformity

The role of the medial capsule and transverse metatarsal ligament in hallux valgus deformity including stability of the first metatarsophalangeal and adjacent joints was investigated in vitro. The three-dimensional positions of the proximal phalanx, first metatarsal, and second metatarsal before and after sectioning the medial capsule and metatarsal ligament were measured using a magnetic tracking system. Valgus deformity of the hallux increased with medial capsule sectioning an average of 22.3 degrees +/- 6 degrees. Valgus deformity of the hallux increased with medial capsule and metatarsal ligament sectioning an average of 27.4 degrees +/- 9.1 degrees. Valgus deformity of the hallux did not change significantly after sectioning the metatarsal ligament only. No significant changes were found in varus and eversion of the first metatarsal, in valgus of the second metatarsal, in the distance between first and second metatarsal heads after sectioning the medial capsule, or in the metatarsal ligament. This study shows the importance of the medial capsule in hallux valgus deformity. The transverse ligament did not contribute substantially to cause the deformity.

Three-dimensional analysis of flatfoot deformity: cadaver study

Eleven fresh-frozen cadaver foot specimens were tested to define changes in tarsal alignment associated with flatfoot, or pes planus, a common clinical problem. The three-dimensional position of four bones (talus, calcaneus, navicular, and first metatarsal) relative to the fixed tibia was determined with a magnetic tracking system in the intact foot and flatfoot conditions. In the flatfoot, the average metatarsal-to-talar position difference was 11.7 degrees +/-4.4 degrees in abduction (P < 0.0001), 10.4 degrees +/-3.6 degrees in dorsiflexion (P < 0.0001), and 10.9 degrees +/-6.0 degrees in eversion (P < 0.0001) compared with the intact foot. The average calcaneal-to-talar position difference was 2.2 degrees +/-2.6 degrees in abduction (P=0.0171) and 2.7 degrees+/-2.0 degrees in eversion (P=0.0012) compared with the intact foot. The average navicular-to-talar position difference was 13.6 degrees +/-5.0 degrees in abduction (P < 0.0001), 10.5 degrees +/-6.6 degrees in dorsiflexion (P=0.0004), and 8.1 degrees +/-3.8 degrees in eversion (P < 0.0001) compared with normal. The average talar-to-tibial position difference was -8.2 degrees +/-3.2 degrees in dorsiflexion (P < 0.001) compared with the intact foot. The average arch height difference was 6.0+/-2.7 mm (P < 0.0001) less than the normal condition. The deformity associated with flatfoot is complex and occurs in multiple joints and in all three planes. An understanding of the normal and pathologic (flatfoot) conditions is necessary to surgically restore appropriate alignment and function in hindfoot reconstruction operations.

Oblique metatarsal osteotomy for intractable plantar keratosis: 10-year follow-up

Twenty patients (14 women and 6 men) (23 feet) had a single oblique osteotomy operation of the 2nd, 3rd, or 4th metatarsal without fixation during an 8-year period. The mean age was 46 years (range, 21-64 years). Each patient had a painful intractable plantar keratosis preoperatively. The average follow-up was 10 years (range, 3-14 years). Postoperatively, reoperation was performed in four feet because of painful callosities. For 13 of the 19 feet that did not have reoperation, patients were limited in footwear or required a shoe insert. Overall results were good for 10 feet, fair for 7 feet, and poor for 6 feet. The only complication was a deep infection that occurred in one foot (good result). Nonunion occurred in one foot and delayed union in one. The average decrease in metatarsal length after osteotomy was 6+/-6 mm. The single oblique lesser metatarsal osteotomy may be successful, but one half of the patients continued to have some degree of pain and most patients had limitations in footwear. Overall results were disappointing, and patients who are offered this procedure should be advised of its limitations.

Peroneal tendon injuries

Injury to the peroneal tendons is a frequently overlooked cause of persistent lateral ankle pain after trauma. Peroneal tendon anatomy, biomechanics, diagnostic studies, and traumatic disorders were reviewed.

Chevron osteotomy of lesser metatarsals for intractable plantar callosities

We performed distal chevron osteotomy of the second, third, or fourth metatarsal for painful plantar callosities in 19 non-rheumatoid patients (16 women, 3 men; 21 feet); their mean age was 59 years (32 to 85). The mean follow-up was four years (2 to 7).

The overall results were good in 16 feet, fair in two, and poor in three, with four patients still having painful plantar callosities. There was union in all feet, but transfer metatarsalgia developed in three and three required an orthosis.

Distal chevron osteotomy for intractable plantar callosities was successful both clinically and radiologically in most patients.

Chevron osteotomy of lesser metatarsals for intractable plantar callosities

We performed distal chevron osteotomy of the second, third, or fourth metatarsal for painful plantar callosities in 19 non-rheumatoid patients (16 women, 3 men; 21 feet); their mean age was 59 years (32 to 85). The mean follow-up was four years (2 to 7). The overall results were good in 16 feet, fair in two, and poor in three, with four patients still having painful plantar callosities. There was union in all feet, but transfer metatarsalgia developed in three and three required an orthosis. Distal chevron osteotomy for intractable plantar callosities was successful both clinically and radiologically in most patients.

Ankle arthrodesis in patients with rheumatoid arthritis

The results of 26 ankle arthrodeses performed for rheumatoid arthritis on 21 patients were reviewed. Tibiotalar arthrodesis was performed in 14 ankles, and tibiotalocalcaneal arthrodesis was performed in 12. External fixation was used in 20 ankles, and internal fixation was used in six. Followup was available in 24 of 26 ankles (19 patients), and averaged 5 years (range, 2-8 years). There was no pain experienced in 19 ankles; mild, occasional pain was experienced in four ankles; and moderate, daily pain was experienced in one ankle. Daily activities were limited in five patients and recreational activities were limited in 11. All patients reported some difficulty walking on uneven terrain. Nearly all patients were satisfied; two were satisfied with reservations and two were dissatisfied. Union was achieved in 25 of 26 (96%) ankles. Ankle arthrodesis is an effective operation in patients with rheumatoid arthritis. Unlike previous reports, union and complication rates in this series were comparable with rates for arthrodesis for posttraumatic and degenerative arthritis.

Reconstruction operations for acquired flatfoot: biomechanical evaluation

A major limitation of operations commonly performed for acquired flatfoot is inadequate correction of alignment. The authors defined the efficacy of two operations, deltoid ligament reconstruction and flexor digitorum longus tendon transfer, for treatment of posterior tibial tendon dysfunction with flatfoot deformity. Twelve fresh-frozen foot specimens were used. A flatfoot deformity was created, and, to simulate the midstance phase of gait, loads were applied axially to the plantar surface of the foot and to appropriate tendons. Foot position improved substantially after deltoid ligament reconstruction but not after flexor digitorum longus tendon transfer. The average increase in arch height after deltoid ligament reconstruction was 10.3 +/- 8.9 mm and after flexor digitorum longus tendon transfer, -0.6 +/- 2.0 mm. Mean arch height after deltoid ligament reconstruction was 2.2 +/- 1.7 mm less than intact arch height and, after flexor digitorum longus tendon transfer, 13.2 +/- 9.0 mm less than intact arch height. Improvement in metatarsal-talar, calcaneal-talar, and talar-tibial positions was significantly greater after deltoid ligament reconstruction than after flexor digitorum longus tendon transfer. Although the authors do not advocate clinical use, the deltoid ligament reconstruction was more effective than flexor digitorum longus tendon transfer in restoring arch alignment in flatfoot.

Arthrodesis for the treatment of arthrosis of the ankle and osteonecrosis of the talus

We evaluated the results of arthrodesis that had been performed for arthrosis of the ankle and osteonecrosis of the talus in nineteen patients. Twelve patients were men, and seven were women. The mean age of the patients was thirty-four years (range, nineteen to fifty-eight years). The median interval between the injury and the index operation was twenty-one months (range, six to 408 months). The arthrodesis was performed at the level of the ankle only in three patients and in both the ankle and the subtalar joint in sixteen. External fixation was used in thirteen patients, internal fixation was used in four, and no fixation was used in two. Supplemental bone graft from the iliac crest was used in fourteen patients, and local bone graft was used in five. The mean duration of follow-up was six years (range, two to fifteen years). The clinical result was excellent in seven patients, good in six, fair in three, and poor in three. Union was achieved in sixteen ankles, but it was delayed in one of them. Complications occurred in four patients: one had a tibial stress fracture, one had an infection at the site of a non-union, and two had malalignment in plantar flexion. Overall, the arthrodesis was successful in these patients. The use of rigid fixation and bone-grafting had a rate of success approximating that reported for primary arthrodesis in patients who do not have avascular necrosis.

Salvage treatment of failed hallux valgus operations with proximal first metatarsal osteotomy and distal soft-tissue reconstruction

We reviewed the results of 15 patients (16 feet) in whom a hallux valgus procedure had failed. Salvage was by proximal crescentic first metatarsal osteotomy with distal soft-tissue reconstruction. Results based on a clinical scale considering the level of pain, activity limitations, support requirement, footwear limitations, and alignment were good in 11, fair in two, and poor in three. Patients were satisfied with the results in 10 feet, satisfied with reservations in four feet, and dissatisfied in two feet. Complications were: transfer metatarsalgia in three, hallux varus in one, and osteotomy nonunion in one. One of the patients required reoperation to bone graft a proximal osteotomy. Metatarsal osteotomy was helpful in the salvage treatment of recurrent, symptomatic hallux valgus when the first metatarsophalangeal joint was functional and painless.

Arthrodesis versus resection arthroplasty for failed hallux valgus operations

The results for 18 patients (20 feet) in whom a hallux valgus procedure had failed were reviewed. Ten patients (11 feet), with a mean age of 63 years, had correction with Keller resection arthroplasty and were observed for an average of 10 years (range, 3-15 years). The hallux valgus angle improved an average of 11 degrees +/- 3 degrees, and the intermetatarsal angle improved an average of 2 degrees +/- 1.7 degrees. Results were good in six feet, fair in four, and poor in one. Eight patients (nine feet), with a mean age of 63 years, had correction with arthrodesis and were observed for an average of 5 years (range, 2-8 years). The hallux valgus angle improved an average of 23 degrees +/- 6.9 degrees, and the intermetatarsal angle improved an average of 2 degrees +/- 3 degrees. Results were good in six feet, fair in two, and poor in one. There were differences between the two operations in terms of patient satisfaction, pain relief, appearance, and footwear. The incidence of metatarsalgia was similar for the two groups. Complications, particularly malalignment, were more common in the resection group. None of the patients required additional revision operation. Resection arthroplasty is a simple procedure and does not require cast immobilization. Resection arthroplasty and arthrodesis are reasonable options for salvage treatment of failed hallux valgus operations in older patients because good results were achieved in six of nine (67%) feet after arthrodesis and in six of 11 (54%) feet after resection.

Subtalar arthrodesis with internal compression for post-traumatic arthritis

We studied retrospectively the results in 24 patients (25 feet) who had been treated by subtalar arthrodesis with internal compression for post-traumatic arthritis from 1988 to 1992. Fifteen patients were men (16 feet) and nine (9 feet) were women. Their mean age was 43 years (22 to 68), and the average duration of follow-up was four years (2 to 6). A single compression screw was used in all feet and iliac-crest bone grafting in ten.

Union was achieved in 24 of the 25 feet (96%). Based on a clinical scale the results were excellent in 10 feet, good in 7, fair in 6, and poor in 2 and on the Angus and Cowell score they were good in 19 feet, fair in 4, and poor in 2. The two poor results were due to nonunion in one patient and reflex sympathetic dystrophy in the other. One reoperation was performed for nonunion. Eighteen patients (18 feet) were satisfied with the results, four were satisfied with reservations, and three were dissatisfied. Progressive ankle and midfoot arthritis did not occur in the absence of pre-existing degenerative changes in these joints.

We conclude that isolated subtalar arthrodesis with internal compression was effective treatment for post-traumatic subtalar arthritis. Iliac-crest bone grafting was not routinely required.

Subtalar arthrodesis with internal compression for post-traumatic arthritis

We studied retrospectively the results in 24 patients (25 feet) who had been treated by subtalar arthrodesis with internal compression for post-traumatic arthritis from 1988 to 1992. Fifteen patients were men (16 feet) and nine (9 feet) were women. Their mean age was 43 years (22 to 68), and the average duration of follow-up was four years (2 to 6). A single compression screw was used in all feet and iliac-crest bone grafting in ten. Union was achieved in 24 of the 25 feet (96%). Based on a clinical scale the results were excellent in 10 feet, good in 7, fair in 6, and poor in 2 and on the Angus and Cowell score they were good in 19 feet, fair in 4, and poor in 2. The two poor results were due to nonunion in one patient and reflex sympathetic dystrophy in the other. One reoperation was performed for nonunion. Eighteen patients (18 feet) were satisfied with the results, four were satisfied with reservations, and three were dissatisfied. Progressive ankle and midfoot arthritis did not occur in the absence of pre-existing degenerative changes in these joints. We conclude that isolated subtalar arthrodesis with internal compression was effective treatment for post-traumatic subtalar arthritis. Iliac-crest bone grafting was not routinely required.

Subtalar arthrodesis for posterior tibial tendon dysfunction and pes planus

Twenty-one patients (21 feet in 18 women and three men) who were treated with subtalar arthrodesis for posterior tibial tendon dysfunction and pes planus at an average age of 60 years (range, 44-75 years) were studied. Mean duration of symptoms was 3 years. All had realignment of the calcaneus in relation to the talus, and all had screw fixation without supplemental bone graft. Average followup was 3 years (range, 2-5 years). All patients had successful union. The tibiocalcaneal angle averaged 13 degrees +/- 3.1 degrees before operation and 6 degrees +/- 1.9 degrees after operation. The lateral talometatarsal, lateral talocalcaneal, and lateral tibiotalar angles all improved significantly. Arch height (navicular height) increase averaged 5 +/- 2.7 mm. Arch length (calcaneal-metatarsal) decrease averaged 4 +/- 3.2 mm. One complication occurred: delayed wound healing (excellent result). Clinical results were excellent in eight feet, good in eight, fair in four, and poor in one. Patients were satisfied with the operative result in 16 feet, satisfied with reservations in four, and dissatisfied with the operative results in one. Subtalar arthrodesis effectively corrects deformity, does not require bone graft, has a high union rate, and is associated with a low complication rate. However, 11 of the 21 patients continued to have some pain, and in patients with preexisting arthrosis of adjacent joints, symptoms may persist.

Subtalar arthrodesis versus flexor digitorum longus tendon transfer for severe flatfoot deformity: an in vitro biomechanical analysis

We defined the mechanical behavior of the foot after an operation for treatment of the flatfoot deformity, subtalar arthrodesis, and compared results with those from flexor digitorum longus tendon transfer. Twelve fresh-frozen human foot specimens were used. Supporting elements were sectioned to create a flatfoot deformity. To simulate midstance phase of gait, loads were applied axially to the plantar foot and to five tendons. Reduction of deformity in metatarsal-talar, calcaneal-talar, and talar-tibial positions was achieved and was significantly greater after subtalar arthrodesis operation than after flexor digitorum longus transfer.

Metatarsal lengthening: case report and review of literature

Shortening of one or more metatarsals may be a cause of metatarsalgia and painful toe deformity. Usually, symptoms are limited and may be successfully addressed with nonoperative treatment. Rarely, operation indicated. This report reviews the surgical techniques, results, and complications. These operations include osteotomy and one-stage distraction with bone grafting, osteotomy and one-stage distraction without bone grafting, osteotomy with gradual distraction and bone grafting, and osteotomy with gradual distraction without bone grafting.

Effect of plantar fasciotomy on stability of arch of foot

Five anatomic specimen feet were studied at three different loading levels to determine the three-dimensional position of the individual bones constituting the arch. Bone displacements were compared before and after plantar fasciotomy. Bone displacements changed to a greater extent with higher loads. With a 222-N load the greatest difference in position in dorsiflexion after fasciotomy occurred at the talar to tibial joint, followed by the metatarsal relative to navicular and navicular to talar joints. The greatest difference in displacement in eversion was at the metatarsal relative to navicular, followed by the navicular to talar and calcaneal to talar joints. The greatest difference in displacement in abduction was at the navicular to talar and then the calcaneal to talar joints. The observed displacement of all joints, with changes about all three axes, was consistent with the finding of flattening of the arch in previous reports on plantar fasciotomy. Thus, these data suggest that sectioning of the fascia, which sometimes is performed for fasciitis, may have an effect on the mechanical behavior of the arch.

Stability of the arch of the foot

We defined the relative contributions of six ligaments in stabilizing the arch of the foot: plantar aponeurosis, long-short plantar ligaments, plantar calcaneonavicular ligament (spring ligament), medial talocalcaneal ligament, talocalcaneal interosseous ligament, and tibionavicular portion of the deltoid ligament. Nineteen fresh-frozen human foot specimens were used. A load of 445 N was applied axially to simulate standing-at-ease posture. Three-dimensional positions of tarsal bones before and after ligament sectioning were determined with the use of a magnetic tracking device. The motions were presented in the form of screw axis displacements, quantitating rotation, and axis of rotation orientation. After sectioning one structure, the arch did not collapse on any specimen and there was no obvious change by visual inspection. There were, however, measurable changes in tarsal bone position. Metatarsal-to-talus total rotation difference was greatest with spring ligament and deltoid ligament sectioning, with an average of 2.1 degrees +/- 1.7 degrees and 2.0 degrees +/- 0.2 degree difference, respectively. Calcaneus-to-talus rotation difference was greatest with talocalcaneal interosseous ligament sectioning, with an average of 1.7 degrees +/- 1.5 degrees. The spring ligament, deltoid ligament, and talocalcaneal interosseous ligament were most important for arch stability.

Acute repair and delayed reconstruction for lateral ankle instability: twenty-year follow-up study

OBJECTIVES

To determine long-term results of patients who underwent primary ligament repair and delayed reconstruction for lateral ligament instability.

DESIGN

Retrospective.

SETTING

Outpatient clinic.

PATIENTS/PARTICIPANTS

Patients who had undergone acute repair or delayed reconstruction at this institution between 1958 and 1977, excluding patients who were deceased or who could not be located.

INTERVENTION

Forty-eight patients (fifty-three ankles) underwent twenty-two primary ligament repairs and thirty-one delayed reconstruction operations.

MAIN OUTCOME MEASUREMENTS

Clinical results graded with clinical scale and radiologic results based on stress radiographs and plain film radiographs.

RESULTS

At an average of twenty years after operation (range 12 to 33 years), patients were satisfied with forty-nine ankles, satisfied with reservations with two ankles, and dissatisfied with two ankles. Clinical results after repair were excellent in twenty ankles, good in one, fair in none, and poor in one. After reconstruction, the results were excellent in twenty-one ankles, good in six, fair in one, and poor in three. In the primary repair group, the mean talar tilt with stress testing improved from 20.7 +/- 10.7 degrees before operation to 2.8 +/- 3.0 degrees after operation. In the reconstruction group, the mean talar tilt improved from 20.7 +/- 8.4 degrees before operation to 2.8 +/- 3.5 degrees after operation.

CONCLUSIONS

Clinical and radiologic results were similar in the repair and reconstruction groups. The majority of severe (Grade III) ankle sprains may be treated nonoperatively, but if residual instability occurs, late reconstruction should achieve satisfactory results.

Ewing's sarcoma of the foot

The results of treatment were reviewed in 16 patients (10 male and six female) who had Ewing's sarcoma of the foot from 1954 through 1992. Mean age was 17 years (range, 10-42 years). The tumor involved the metatarsals (six patients), phalanges (four), calcaneus (three), navicular (one), talus (one), and calcaneus and phalanx (one). Seven patients had metastatic disease at the time of diagnosis, and only one of these patients survived. None of the patients with pulmonary metastasis at presentation survived. Nine patients had localized disease at the time of diagnosis, and eight survived. In the overall series, nine of the 16 patients were alive at followup (eight survived at least 5 years). Diagnosis was established at an average of 14 months from the onset of symptoms: 7 months in forefoot tumors and 22 months in hindfoot tumors. None of the six patients who had a resection had local failure. Seven of the 10 patients with forefoot lesions survived, and two of the six patients with hindfoot lesions survived. Treatment of Ewing's sarcoma of the foot by local control with radiation or operation and systemic control with chemotherapy is recommended. Survival appears to be better in patients who present with localized disease and forefoot lesions. Survival is worse in patients who present with metastatic disease. Surgical treatment appears to have an important role in local control and survival.

Subtalar joint stability. Talocalcaneal interosseous ligament function studied in cadaver specimens

We used 6 fresh-frozen foot specimens to evaluate the contribution of the talocalcaneal interosseous ligament (IOL) in stabilizing the subtalar (talocalcaneal) joint. The tibia and ankle joint were secured, and the calcaneus was subjected to a bending and axial force applied circumferentially. The position of the calcaneus relative to the talus was monitored with a magnetic tracking system. Motion was recorded at every half degree in the 0 degree to 360 degrees arc before and after sectioning of the IOL. The results in the intact feet indicated that, with circumferential loading of the subtalar joint, there were two stable zones (supination stable zone, pronation stable zone) during which little displacement occurred and two transition zones during which the supination and pronation movement occurred. There was a greater degree of supination displacement after IOL sectioning (p = 0.008), but no pronation displacement. The IOL contributed substantially to subtalar joint stability, particularly in supination.

Quantitative analysis of the intrinsic muscles of the foot

BACKGROUND

Understanding muscle architecture of the foot may assist in the design of surgical procedures such as tendon transfer, biomechanical modeling of the foot, prosthesis design, and analysis of foot function. There is limited published information regarding foot intrinsic muscle architecture.

METHODS

Eleven fresh-frozen cadaveric feet were studied from eight males and three females. Twenty-eight intrinsic muscles were dissected in each foot, and measurements of fiber length, muscle length, and muscle volume obtained using calipers and water displacement technique. The physiologic cross-sectional area, fiber/muscle length ratio, muscle mass fraction, and tension fraction were then calculated.

RESULTS

Intrinsic muscle length was related to foot size. The mean fiber length ranged from 13.6 mm (first plantar interosseous) to 28.0 mm (second extensor digitorum brevis). The mean muscle length ranged from 24.8 mm (adductor hallucis transverse) to 115.8 mm (abductor hallucis). The mean muscle volume ranged from 0.4 cc (fifth lumbrical) to 15.2 cc (abductor hallucis). The physiologic cross-sectional area ranged from 0.28 cm2 (second and third lumbrical) to 6.68 cm2 (abductor hallucis). The fiber/ muscle ratio ranged from 0.20 (abductor hallucis) to 0.82 (adductor hallucis transverse). The mass fraction ranged from 0.33% (fifth lumbrical) to 16.59% (abductor hallucis). The tension fraction ranged from 0.34% (fifth lumbrical) to 15.37% (abductor hallucis).

CONCLUSIONS

The abductor hallucis and adductor hallucis oblique had much greater physiologic cross-sectional areas compared to those of the other intrinsic muscles. The lumbrical muscles had relatively low physiologic cross-sectional areas. These observations illustrate the underlying structural basis for the functional capacities of the intrinsic muscles of the foot.

Analysis of longitudinal arch supports in stabilizing the arch of the foot

Two orthotic devices commonly prescribed as arch supports were studied to evaluate their efficacy in stabilizing the foot. Fourteen cadaveric feet were mounted in a loading frame, and an axial load of 222, 445, or 667 N was applied while three-dimensional positions of the talus, calcaneus, navicular, and first metatarsal were monitored with a magnetic tracking system. Feet were tested with and without the use of two commonly prescribed arch supports. The two indices used to assess arch stabilization were arch height and joint rotation. Joint rotations consistently increased on load application. Significant differences were observed with Inserts 1 and 2 in metatarsal talar abduction, dorsiflexion and eversion, calcaneal talar eversion, and talar tibial dorsiflexion. Arch height significantly increased with both inserts. Contrary to previously published results, the arch supports that were studied provided measurable improvement in arch stability in a simulated standing at ease position.

Analysis of clinical grading scales for the foot and ankle

To evaluate grading methods used to report clinical results, we reviewed 1,607 articles related to the foot and ankle published in six orthopaedic journals from 1980 through July 1993. Many clinical studies use criteria such as patient satisfaction to grade results. A numeric score or grade was used in 346 articles: 238 used a grade only, 90 used a numeric score and grade, and 18 used a numeric score only. The numeric score or grade was usually, but not always, reported with details of the individual clinical factors that composed the score or grade. Twenty-three articles used a score before and after treatment. Statistics were used in 62 articles, and in 6 of those the statistics were used to compare clinical condition before and after treatment. This study demonstrated the array of grading methods used in selected orthopaedic journals and indicated the need for standardized grading techniques to allow for more meaningful interpretation of the orthopaedic literature.

Physiological elongation of ligamentous complex surrounding the hindfoot joints: in vitro biomechanical study

Ligaments surrounding the hindfoot joints play an important role in hindfoot stability. This in vitro study investigated anatomical and biomechanical characteristics of nine major ligamentous structures, including length and orientation at neutral position and physiological elongation with the foot in five different positions relative to the neutral position. The results showed that ligament elongation depended on the ligament length, orientation in neutral position, and movement of bones to which they were attached.

Gait abnormalities following resection of talocalcaneal coalition

Eleven patients (fourteen feet) had resection of a coalition of the middle facet of the talocalcaneal joint because of symptoms that had been present for a mean of four years (range, 0.5 to nine years). The mean age at the time of the resection was seventeen years (range, thirteen to thirty-two years). Nine patients were male and two were female. Five feet had resection of the bone bridge with interposition of fat or tendon, and nine had resection without any interposed material. The mean duration of follow-up was six years (range, two to thirteen years). The clinical result was excellent for five feet, good for four, fair for three, and poor for two. Inversion was 8 +/- 4.5 degrees (mean and standard deviation) on the involved side and 17 +/- 6.2 degrees on the uninvolved side (p = 0.002). Three feet later had evidence of osteoarthrosis of the subtalar joint. Gait analysis demonstrated decreased motion of the hindfoot and the ankle, compared with that in normal subjects and with that in the contralateral (uninvolved) foot, in the sagittal and coronal planes during walking on a level surface. Motion was also reduced, particularly in the sagittal and coronal planes, during walking on a side slope. Ground-reaction forces (F8 and F9), temporal force factors (T2, T3, and T7), and the percentage of the gait cycle that consisted of the stance phase on the side-sloping walkway were different from those in normal subjects or in the uninvolved foot. These data indicate that, although most of our patients who had resection of a talocalcaneal coalition had a successful clinical result, most had a residual functional deficit.

Kinematics and contact characteristics of the first metatarsophalangeal joint

We studied six fresh frozen cadaver feet to define the three-dimensional motion of the hallux proximal phalanx in relation to the first metatarsal and to describe the contact features of the first metatarsophalangeal joint. Six tendons to the hallux were loaded to simulate dynamic loading of the hallux. A magnetic tracking system was used to monitor the three-dimensional movement of the proximal phalanx while the toe position was changed from a neutral position to full extension by adjusting the tendon loads. The average surface area was 0.38 +/- 0.08 cm2 in the neutral position; it decreased with toe extension and was the lowest (0.04 +/- 0.03 cm2) at the full extension position. Contact distribution of the proximal phalanx did not change substantially throughout the arc of motion. However, for the metatarsal articular surface, the contact distribution shifted dorsally with increasing degrees of extension. These data are consistent with the observation that chondral erosions associated with hallux rigidus and degenerative arthritis initially affect the dorsal articular surface of the metatarsal, and implant arthroplasty often fails from component loading dorsally. The current technique of determining joint contact characteristics is applicable not only for the first metatarsophalangeal joint but also other joints that have not been studied because of shortcomings with more conventional methods.

Three-dimensional analysis of normal ankle and foot mobility

We defined foot and ankle motion with respect to the neutral position. Thirteen normal fresh-frozen specimens of the human foot were used. The foot was placed in the extreme positions of pronation, supination, dorsiflexion, and plantar flexion, and positions of multiple bones were monitored simultaneously with a magnetic tracking device to determine rotation of the talocrural, subtalar, metatarsal-navicular, and talonavicular joints under the various conditions. In pronation, the most rotation occurred at the metatarsal-navicular level, followed by the navicular-talar, talar-tibial, and calcaneal-talar levels. In supination, most rotation occurred at the navicular-talar level, followed by the calcaneal-talar, talar-tibial, and metatarsal-navicular levels. In dorsiflexion, most rotation occurred at the talar-tibial level, followed by the navicular-talar, calcaneal-talar, and metatarsal-navicular levels. In plantar flexion, most rotation occurred at the talar-tibial level, but there was considerable motion at the navicular-talar, metatarsal-navicular, and calcaneal-talar levels. Understanding the specific joint motions that occur with various positions of the foot and ankle is important because measurements of joint mobility may assist in establishing diagnoses, monitoring clinical conditions, determining indications for operative treatment, assessing results of treatment, and following the progress of rehabilitation.

Mechanical behavior of the foot and ankle after plantar fascia release in the unstable foot

The change in position of the bones of the foot was studied in three dimensions after plantar fascia release in intact and destabilized feet. Fifteen fresh-frozen human foot specimens were used. Physiologic loads of 445 newtons were applied axially to simulate standing at ease, and the three-dimensional position of tarsal bones was determined with a magnetic tracking device. The positions were presented in the form of screw axis displacements, quantitating rotation, and axis of rotation orientation. After fasciotomy in the six intact feet, significant differences in rotation were observed at the talotibial and calcaneotalar levels. After fasciotomy in the four unstable feet with three supporting elements sectioned, significant differences in position were observed at the talotibial joint and a significant decrease in arch height was observed. After fasciotomy in the five unstable feet with five supporting elements sectioned, significant differences in rotation were observed at the talotibial joint (mean, 5.5 +/- 1.6 degrees; P = 0.001), calcaneotalar joint (mean, 6.1 +/- 2.1 degrees; P = 0.003), and metatarsotalar level (mean, 9.3 +/- 4.1 degrees; P = 0.007). The average decrease in arch height was 7.4 +/- 4.1 mm (P = 0.015). Displacement of all joints tested occurred after fasciotomy, with rotation about all three axes. These changes in displacement were more pronounced in unstable or destabilized feet. The data suggest that operations involving fasciotomy affect arch stability and should not be performed in patients with evidence of concomitant pes planus deformity, because of the likelihood of further deformation.

Effect of the posterior tibial tendon on the arch of the foot during simulated weightbearing: biomechanical analysis

A cadaver study was performed to determine the effect of the posterior tibial tendon (PTT) on the stability of the foot in simulated midstance phase of gait. Thirteen fresh-frozen human foot specimens were used. Loads were applied axially and to each tendon. Three-dimensional positions of tarsal bones before and after tendon loading were determined with the use of a magnetic tracking device. Significant differences in tarsal bone positions were observed with application of loads to the Achilles, posterior tibial, flexor digitorum longus, peroneus longus, and peroneus brevis tendons at the metatarsotalar, calcaneotalar, and talotibial joints and in overall arch height. These tendon loads caused position changes toward arch flattening or mild pes planus deformity. Significant differences in tarsal bone positions were observed with PTT loading compared with no PTT loading in metatarsotalar, calcaneotalar, and talotibial levels as well as arch height. The PTT caused position changes toward restoring the arch alignment. These data suggest that the PTT is an important stabilizer of the arch of the foot.

Clinical results of the Mayo total ankle arthroplasty

Two hundred and four primary Mayo total ankle arthroplasties were performed in 179 patients at the Mayo Clinic from 1974 through 1988. We evaluated the clinical result after 160 arthroplasties in 143 patients who had been followed for two years or more (mean, nine years; range, two to seventeen years). The result was good for thirty-one ankles (19 per cent), fair for fifty-five (34 per cent), and poor for seventeen (11 per cent); fifty-seven arthroplasties (36 per cent) were considered to be a failure (defined as removal of the implant). Adequate preoperative and follow-up radiographs were available for 101 ankles (eighty-nine patients). There was radiographic evidence of loosening of eight tibial components (8 per cent) and fifty-eight talar components (57 per cent), but we found no association between the clinical and radiographic results. Complications occurred after nineteen (12 per cent) of the 160 arthroplasties, and ninety-four additional reoperations were necessary after sixty-six (41 per cent). On the basis of these findings, we do not recommend ankle arthroplasty with a constrained Mayo implant for rheumatoid arthritis or osteoarthrosis of the ankle.

Nonoperative treatment of plantar interdigital neuroma with a single corticosteroid injection

Patients who received a single corticosteroid injection for treatment of third webspace plantar interdigital neuroma were studied retrospectively. Forty-three patients (51 feet) were available for followup study (followup mean, 4 years; range, 2 to 6 years). Mean age of patients was 53 years. Pain initially was relieved in 36 patients (41 feet [80%]). Twenty-four feet (47%) ultimately required surgical excision, while most of the remaining 27 feet (53%), which had not been treated surgically, were the source of residual symptoms in patients. A single corticosteroid injection cannot be recommended as a cure for symptoms of third webspace neuroma, but it can be offered as a temporizing measure or as nonoperative treatment. A single corticosteroid injection does not preclude a successful surgical result.

Contact features of the talonavicular joint of the foot

Seven cadaveric feet were studied to determine the distribution of the contact area of the talonavicular joint. Feet were loaded axially with soft tissue structures intact and after sectioning of static elements that support the arch. Bony displacement was monitored with a magnetic tracking device, and joint contact was determined from proximity calculations of digitized joint surfaces. With physiologic loading of the intact foot, the number of regions in contact increased. In the unstable foot, there was a shift in contact distribution toward more dorsal and central regions of the navicular bone. This is consistent with the clinical observation that fatigue fractures, acute fractures, and nonunion of navicular fractures occur often in the central navicular body. The alteration in contact characteristics in unstable feet is also consistent with the observation that osteoarthrosis of the hindfoot joints occurs commonly with long-standing arch instability or pes planus deformity.

Kinematics of the normal arch of the foot and ankle under physiologic loading

We studied 15 cadaver feet to determine three-dimensional motion of selected tarsal bones under axial loading at three different loading levels. We determined the motion of individual joints and also the rotation of the tarsal bones in relation to the tibia. Joint rotations increased consistently with higher loads. The naviculartalar joint had the greatest total screw axis rotation, which averaged 9.4 degrees +/- 2.2 degrees at 667 N of load, followed by the first metatarsal-navicular (mean, 7.2 degrees +/- 1.5 degrees), talartibial (mean, 5.2 degrees +/- 1.6 degrees), and calcaneal-talar (mean, 4.4 degrees +/- 1.7 degrees) joints. The observed changes indicate the need for assessment of foot and ankle alignment clinically and radiologically while the patient is weightbearing.

Late versus early repair of Achilles tendon rupture. Clinical and biomechanical evaluation

Eleven patients who had late reconstruction for Achilles tendon rupture were compared with 10 patients who had immediate repair. The followup period averaged 8 years for both groups. Results, based on a clinical score, were successful (excellent or good) for all but 1 patient. Although manual testing demonstrated normal plantar flexion strength in all but 1 patient, significant differences were seen in isometric and isokinetic plantar flexion strength of the involved sides as compared with the uninvolved sides of these patients. The patient with the unsuccessful result had abnormalities in vertical, foreaft, and medial-lateral force components of the ground reaction force. Three-dimensional motion analysis showed decreased total motion in the sagittal plane on the operated side as compared with the unoperated side in this patient. The data indicated that patients with late reconstruction of Achilles tendon rupture have successful clinical results comparable with those of early repair.

Shock-absorbing effect of shoe insert materials commonly used in management of lower extremity disorders

The efficacy of 3 shock-absorbing materials was compared by determining impact characteristics with a drop test method and also by testing the effect of each material when used as a shoe insert in 16 asymptomatic subjects. Peak vertical ground reaction force (F1, F2, F3) and temporal force factors (T1, T2, T3) were obtained with a force plate at a high-frequency sampling rate. Impact force, impact time, impact slope, and impact energy were determined. A standard weight was dropped from 3 heights on each material covering the force plate while reduction of peak force was compared. Impact force was attenuated most effectively by Insert 3 (polymeric foam rubber) and averaged 11% less than that in shoes without inserts. Impact time was increased for all 3 inserts. Impact slope and impact energy were reduced significantly in Insert 3. There was a significant difference in peak vertical force F1 for all 3 inserts, in vertical force F2 for Insert 2 (viscoelastic polymeric material), and in vertical force F3 for Insert 2. Drop-test studies showed that at all ball heights, the highest mean peak force was observed consistently in Insert 2.

Displaced intra-articular fractures of the calcaneus treated non-operatively. Clinical results and analysis of motion and ground-reaction and temporal forces

Twenty-seven patients who had a unilateral displaced intra-articular fracture of the calcaneus were managed with a cast instead of with reduction or an operation. The clinical result after a mean of six years (range, two to ten years) was excellent in five patients, good in five, fair in seven, and poor in ten. The sixteen patients who were re-examined for this study and for whom the gait was analyzed demonstrated abnormalities in ground-reaction force with regard to vertical force (F3) and temporal force factors (T2, T3, T6, and T9). Analysis of temporal and distance factors showed a trend toward a decreased proportion of single-limb support on the involved side. Three-dimensional motion analysis of the ankle and hindfoot was performed with electrogoniometers as the subject walked on a level surface, on a 10-degree side-slope, and up and down stairs. Motion was decreased in the sagittal, coronal, and transverse planes during walking on level ground and on a side-sloping surface. Significant decreases in motion in these planes were also seen during walking up and down stairs. Although these patients did not have a subsequent reconstructive operation, most had a residual functional deficit.

Material properties of the plantar aponeurosis

Material properties of the plantar aponeurosis were determined by a two-dimensional video tracking method to simultaneously measure the aponeurosis deformation. Failure loads averaged 1189 +/- 244 N and were higher in men. Average stiffness of the intact fascia was 203.7 +/- 50.5 N/mm at a loading rate of 11.12 N/sec and it did not vary significantly for the loading rates of 11.12 to 1112 N/sec. The high tensile loads required for failure were consistent with clinical and biomechanical studies and indicated the importance of the aponeurosis in foot function and arch stability.

Survivorship analysis of the Mayo total ankle arthroplasty

From 1974 until the end of 1988, 204 primary Mayo total ankle arthroplasties were performed at the Mayo Clinic. By means of actuarial analysis, we determined the cumulative rates of survival with failure (defined as removal of the implant) as the end point. The average duration of follow-up was nine years (range, two to seventeen years). By applying the Cox proportional-hazards general linear model, we identified two independent variables that were associated with a significantly higher risk of failure: a previous operative procedure on the ipsilateral foot or ankle and an age of fifty-seven years or less. The overall cumulative rate of survival at five, ten, and fifteen years was 79, 65, and 61 per cent, respectively. The probability of an implant being in situ at ten years was 42 per cent for patients who were fifty-seven years old or less and who had had previous operative treatment of the ipsilateral ankle or foot and 73 per cent for those who were more than fifty-seven years old and who had had no such previous operative treatment. We do not recommend the use of the Mayo total ankle arthroplasty, particularly in younger patients who have had a previous operative procedure on the ipsilateral ankle or foot.

Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes

Four rating systems were developed by the American Orthopaedic Foot and Ankle Society to provide a standard method of reporting clinical status of the ankle and foot. The systems incorporate both subjective and objective factors into numerical scales to describe function, alignment, and pain.

Survivorship analysis of implant arthroplasty for the first metatarsophalangeal joint

During a 21-year period at the authors' institution, 93 primary implants of the first metatarsophalangeal joint were performed on 79 patients (12 men and 67 women). Their mean age was 56 years (range, 19 to 75 years). The average duration of follow-up evaluation in 75 patients who were alive and without reoperation was 12 years (range, two to 17 years). With the proportional hazards general linear model, young age was identified as a significant risk factor for poor survival: at ten years, implant survival was 82% in patients 57 years of age or younger, and 90% in patients older than 57 years. The overall probability that an implant would not have been removed was 86% at ten years after arthroplasty and 82% at 15 years.