Foot & Ankle International

Hallux varus occurs most frequently as result of excessive surgical correction of musculoligamentous imbalance around the metatarsophalangeal (MTP) joint of the great toe (lateral release and medial capsuloligamentous tensioning). If untreated, the condition may lead to motion loss and degenerative arthritis. In this series, 14 cases of hallux varus were treated. Medial arthrolysis was done in each case. In five cases, reconstruction of the lateral ligament (with a 1.5-mm Ligapro suture), using a new technique, accompanied the medial release. Arthrodesis of the MTP was done in nine cases treated when there was already stiffness and arthrosis. According to a 100-point scoring system, the results were excellent in 56% and good in 44% of the MTP joint arthrodesis cases. Results were excellent in 100% of the mobilizing technique cases using Ligapro suture.

This investigation studied the effects of simulated plantar flexor muscle activity on forefoot loading using a static cadaver model. Nine cadaver feet were mounted in an apparatus in the heel rise position. Using computer-controlled and pneumatic actuators, forces were simultaneously applied to the tendons of the triceps surae, flexor hallucis longus, flexor digitorum longus, peroneus brevis and longus, and tibialis posterior until 750 N of ground reaction force was achieved, at which time forefoot plantar pressure patterns were captured immediately with a pedobarograph. Second metatarsal bending moments were calculated from strain gauge data collected concurrently. Consecutive loading cycles were performed with sequential elimination of simulated muscle force from each tendon except the Achilles. Loss of simulated flexor hallucis longus activity significantly decreased great toe contact forces and significantly increased forces under the forefoot. Simulated loss of both the flexor hallucis longus and flexor digitorum longus caused significant decreases in contact area, pressure, and force beneath the toes and significant increases in contact area and force under the forefoot. Bending moments in the second metatarsal were shown to vary directly with peak pressure under the second metatarsal head (r = 0.801). These findings demonstrate the load distributing function of the extrinsic plantar flexors during heel rise.

From 1981 to 1985 28 ankle arthrop! lasties were performed using a congruent and cylindrical ankle design. The talus component was an anatomically shaped cap to cover the talus dome and the facets. The tibial component was congruent toward the talus and had two parallel bars on the back for fixation into the distal tibia. The diagnosis was osteoarthritis in 15 cases and rheumatoid arthritis in 11 cases (two bilateral cases). There were seven failures, giving a cumulative estimated survival rate of 70% for the prosthesis at 12 years.

The plantar plate is a rarely seen, yet central structure to the lesser metatarsal phalangeal (MP) joint. Thirty cadaver lesser MP joints were studied to obtain a detailed description of the plate, including its dimensions, connections, and histology. The plate was found to be made of fibrocartilage with fiber orientation which suggests that it withstands tensile loads in line with the plantar fascia as well as the compressive loads from the metatarsal head. The plantar plate was the most substantial distal insertion of the plantar fascia. Impressive plantar plate attachments were noted to the proximal phalanx, the major longitudinal bands of the plantar fascia, and the collateral ligaments. The plate and collateral ligaments formed a substantial soft tissue box connected to the sides of the metatarsal head. From the dissections, it is apparent that malposition of the toe at the MP joint is likely over time to be associated with pathology in both the collateral ligaments and the plate. Because of these attachments and a close association with the flexor tendons to the lesser toe, the plate can be compared with the sesamoid mechanism of the first MP joint.

Forty cases of hallux rigidus treated by Silastic hemiarthroplasty over an average period of 110 months have been reviewed here. As many as 36% (14 feet) of the patients were unhappy with the results of their operation. Six implants had to be removed because of increasing pain and fragmentation of the prosthesis. These patients improved after the prosthesis was removed. It is concluded that Silastic hemiarthroplasty does not give an acceptable level of good results when compared with published reports of other forms of treatment. The probable causes of the high dissatisfaction rate are discussed.

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 navicular-talar joint had the greatest total screw axis rotation, which averaged 9.4° ± 2.2° at 667 N of load, followed by the first metatarsal-navicular (mean, 7.2° ± 1.5°), talar-tibial (mean, 5.2° ± 1.6°), and calcaneal-talar (mean, 4.4° ± 1.7°) joints. The observed changes indicate the need for assessment of foot and ankle alignment clinically and radiologically while the patient is weightbearing.

The role of relocation of tibialis posterior tendon insertion in the treatment of symptomatic accessory navicular and its relation to the pes planus was studied in 28 patients with symptomatic accessory navicular. Two hundred non-affected individuals were used as control. The calcaneal pitch angle measured radiographically, was used as an indicator of pes planus. All patients had had an excision of the accessory navicular and relocation of the tibialis posterior tendon insertion (Kidner procedure). The average follow-up was 3.2 years. The results were good in 27 patients, and fair in 1 patient, and there were no poor results. Most of the patients demonstrated that the pain and the fatigue signs of the foot and the leg have been improved. Only 3 of 25 patients clinically showed an improvement of the medial longitudinal arch. The calcaneal pitch angle in patients with symptomatic accessory navicular was significantly (14.8°) lower than that in normal subjects (21.4°). An association of pes planus and symptomatic accessory navicular was shown. The Kidner procedure gave good results in the relief of pain and fatigue in patients with symptomatic accessory navicular. The procedure did not significantly restore the height of the medial arch.

A retrospective review was made of all patients operated on by the two senior authors from January 1985 to January 1993 for problems with Kirschner wire breakage following forefoot surgery. Thirty-three broken K-wires in 27 patients were encountered. All of these were 0.045-inch K-wires that had been placed across the metatarsophalangeal (MTP) joint of the lesser toes. In no case was there breakage of a K-wire that was larger than 0.045 inches or that did not cross the MTP joint.

The medical records and radiographs of 565 consecutive patients having fixation with 0.045-inch K-wires that crossed the MTP joints of the lesser toes were then reviewed. A total of 1002 K-wires were used with an overall failure rate of 3.2% (4.8% of the patients). All of these K-wires failed just proximal to the point of entry into the metatarsal head. No intra-articular retained fragments were noted. Twenty-five of the retained fragments were completely within the metatarsal head and shaft, and eight of these fragments pierced the cortex of the metatarsal proximally.

Twenty-three patients with retained fragments were examined in follow-up and in no case could the retained fragment be palpated or directly related to postoperative symptoms. Of the three patients who complained of persistent pain, two had mild pain with persistent MTP synovitis and one had severe pain due to lateral deviation of the toe after surgery.

Patients with rheumatoid arthritis who underwent metatarsal head excision were noted to have a higher rate of failure (10.3% of patients, 4.0% of K-wires) than those without rheumatoid arthritis or metatarsal head excision (3.3% of patients, 2.3% of K-wires). Also four of the six cases with multiple K-wire breakage in the same foot had rheumatoid arthritis.

One hundred twenty-four children with intoeing and 80 age-matched controls were investigated with the Kistler force plate. Tr2, reflecting the maximum external rotational ground reaction torque, is reduced by 30% to 40% in all intoeing children. There also is an appreciably shorter pathway of the point of application of the ground reaction force in the Y-direction (from 20% to 25%) and an obvious medial shift of the point of application of the ground reaction force in the X-direction (from 105% to 290%), from heel strike to toe-off as compared with controls. In spontaneous correction of intoeing, point of application of the ground reaction force in the X-direction becomes more close to normal. The “foot progression angle,” which can easily be calculated from the force plate measurements to judge the degree of intoeing, is different from the values in the literature.

The rotational movements of the tibia and calcaneus that occur with dorsiflexion-plantarflexion and axial loading were studied in cadaver foot-leg specimens using an unconstrained testing apparatus. Independent of the foot flexion position, significant internal rotation of the tibia and eversion of the calcaneus were noted after the ankle complex was axially loaded. Independent of loading, 10° of dorsiflexion resulted in 0.1° of eversion and 2.1° of internal rotation of the tibia. Conversely, 10° of plantarflexion resulted in 1.6° of inversion and 1.3° of external rotation of the tibia. The induced rotational movements of the tibia and the calcaneus differed significantly between the specimens. These results suggest that the foot “axes” did not change by axially loading the ankle complex and they support previous reports that the ankle complex uses different axes for dorsiflexion and plantarflexion.

A 64-year-old woman was treated for an idiopathic complete rupture of the posterior tibial tendon with transfer of the flexor digitorum longus tendon to the navicular. After an initial excellent result, she returned 41 months later after experiencing a sudden pop in the medial retromalleolar area, followed by progressive medial ankle pain. At reoperation, a complete rupture of the flexor digitorum longus tendon was noted at its insertion into the navicular. Reconstruction was performed utilizing a sliding lengthening of the flexor digitorum longus tendon and reattachment to the navicular with a suture anchor. Clinical improvement was noted at the 12-month follow-up evaluation. This case presentation is of clinical interest, as late acute failure of a flexor digitorum longus tendon transfer for posterior tibial tendon rupture has not been reported previously.