Kitaoka, Harold B.

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° P = 0.001), calcaneotalar joint (mean, 6.1 ± 2.1° P = 0.003), and metatarsotalar level (mean, 9.3 ± 4.1° 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.

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.

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.

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.

In spite of the common occurrence of pes planus and multiple operations that have been reported to relieve the associated symptoms, there is little published on the relative contribution of various structures to stabilization of the arch of the foot. Twelve fresh-frozen human cadaveric feet were loaded along the tibial axis with compressive loads of 230, 460, and 690 newtons with the specimens intact and after sequential sectioning of plantar fascia, plantar ligaments, and spring ligament. Structures were sectioned in six different sequences and changes in vertical and horizontal dimensions of the medial arch were measured. The highest relative contribution to arch stability was provided by the plantar fascia, followed by plantar ligaments and spring ligament. Plantar fascia was a major factor in maintenance of the medial longitudinal arch. Its division in the cadaveric feet decreased arch stiffness by 25%.

Implant removal and synovectomy were used to treat the failure of 14 first metatarsophalangeal joint implant arthroplasties. Revision surgery was performed at an average of 3.1 years after arthroplasty. Follow-up (average 4.9 years) was possible in 10 patients, and clinical results were excellent in seven patients, good in one patient, fair in one patient, and poor in one patient. No significant changes in alignment occurred, although a trend toward toe extension was noted. Dynamic force plate studies in these patients demonstrated less pressure under the first metatarsal head and greater loading under the lateral forefoot. The great toe had less contact time during gait in the involved feet than in the control feet.

Thirteen consecutive patients underwent plantar fasciotomy in 16 feet for intractable plantar fasciitis and had follow-up from 4.5 to 15 years. Plantar fasciotomy was successful (good or excellent results) for 71% of the 14 feet operated on and for which follow-up data were available. However, time to full recovery was prolonged, additional treatment was frequently required, and abnormalities of foot function persisted. Flattening of the longitudinal arch occurred. Dynamic force-plate studies showed differences in peak vertical, fore-aft, and lateralmedial forces between patients and matched controls. More rapid progression of weightbearing along the longitudinal axis of the foot during stance phase in patients indicated avoidance of heel loading.

Bunionectomy with medial capsulorrhaphy was performed on 54 feet (37 patients) and follow-up was obtained on 49 feet (33 patients) at a mean of 4.8 years postoperatively. Results were excellent in 17 feet, good in 16, fair in 7, and poor in 9. Mean motion of the first metatarsophalangeal joint was 81°. The primary reason for failure was recurrent deformity. Patients were dissatisfied with the results in 41% of the feet. Mean intermetatarsal 1–2 angle increased 1.7° and mean metatarsophalangeal-1 angle increased 4.8°. The operation was significantly more successful in patients who underwent it for painful medial eminence. Bunionectomy with medial capsulorrhaphy is recommended for elderly patients with symptoms primarily due to prominent medial eminence, and its application for the young patient with significant hallux valgus deformity is limited.

Nineteen distal chevron metatarsal osteotomy operations were performed in 13 patients with painful bunionette. The average duration of follow-up was 7.1 years. Mean forefoot score improved from 35.8 points to 73.9 points out of a possible 75 points. Intermetatarsal 4–5 angle, metatarsophalangeal 5 angle, and forefoot width improved significantly. Overall results were considered good in 17 feet and fair in 2; there were no failures. Complications were transfer metatarsalgia (1 foot) and wound infection (1 foot). Distal chevron fifth metatarsal osteotomy is effective treatment for symptomatic bunionette.

The extraosseous and intraosseous vascular anatomy to the fifth metatarsal as visualized in a group of below-the- knee amputation specimens has been described. The extrinsic circulation to the area is provided by the dorsal metatarsal artery, the plantar metatarsal arteries, and the fibular plantar marginal artery. These three source arteries supply branches to the metatarsal and adjacent joints. The intraosseous vascularity consists of a periosteal plexus, a nutrient artery, and a system of metaphyseal and capital vessels.