Greg A. Horton

Prospective Controlled Trial of STAR Total Ankle Replacement versus Ankle Fusion: Initial Results

Background: Mobile-bearing ankle replacements have become popular outside of the United States over the past two decades. The goal of the present study was to perform a prospective evaluation of the safety and efficacy of a mobile-bearing prosthesis to treat end stage ankle arthritis. We report the results of three separate cohorts of patients: a group of Scandanavian Total Ankle Replacement (STAR) patients and a control group of ankle fusion patients (the Pivotal Study Groups) and another group of STAR total ankle patients (Continued Access Group) whose surgery was performed following the completion of enrollment in the Pivotal Study. Materials and Methods: The Pivotal Study design was a non-inferiority study using ankle fusion as the control. A non-randomized multi-centered design with concurrent fusion controls was used. We report the initial perioperative findings up to 24 months following surgery. For an individual patient to be considered an overall success, all of the following criteria needed to be met: a) a 40-point improvement in total Buechel-Pappas ankle score, b) no device failures, revisions, or removals, c) radiographic success, and d) no major complications. In the Pivotal Study (9/00 to 12/01), 158 ankle replacement and 66 arthrodesis procedures were performed; in the Continued Access Study (4/02 to 10/06), 448 ankle replacements were performed, of which 416 were at minimum 24 months post-surgery at time of the database closure. Results: Major complications and need for secondary surgical intervention were more common in the Pivotal Study arthroplasty group than the Pivotal Study ankle fusion group. In the Continued Access Group, secondary procedures performed on these arthroplasty patients decreased by half when compared with the Pivotal Arthroplasty Group. When the Pivotal Groups were compared, treatment efficacy was higher for the ankle replacement group due to improvement in functional scores. Pain relief was equivalent between fusion and replacement patients. The hypothesis of non-inferiority of ankle replacement was met for overall patient success. Conclusion: By 24 months, ankles treated with STAR ankle replacement (in both the Pivotal and Continued Access Groups) had better function and equivalent pain relief as ankles treated with fusion. Level of Evidence: II, Prospective Controlled Comparative Surgical Trial

Isolated subtalar arthrodesis.

Forty-eight isolated subtalar arthrodeses in 44 patients with an average follow-up of 59.5 months were retrospectively reviewed. Original diagnoses included talocalcaneal coalition, healed calcaneal fracture with subtalar arthrosis, acquired flatfoot because of posterior tibial tendon dysfunction, degenerative subtalar arthrosis, subtalar instability, and psoriatic arthritis. Ninety-three percent of patients were very satisfied or satisfied with their treatment. Pain and function improved significantly, and the American Orthopaedic Foot and Ankle Society ankle-hindfoot score at follow-up was 89. There were six unsatisfactory results: three feet had calcaneal fractures and three were malpositioned. Union was achieved in all cases. Transverse tarsal motion was diminished by 40%, dorsiflexion by 30%, and plantarflexion by 9%. There was a 36% and 41% incidence of mild radiographic progression of arthrosis in the ankle and transverse tarsal joint, respectively. Isolated subtalar arthrodesis provided a highly successful result in the disease presented, and this study provides support for the use of a selected hindfoot fusion procedure for specific indications.

Popliteal Sciatic Nerve Block for Postoperative Analgesia

Eighty-six patients were evaluated prospectively following the placement of a sciatic nerve block in the popliteal fossa after a major foot or ankle operation. Needle placement was guided by a peripheral nerve stimulator and 30 ml of 0.5% bupivacaine with epinephrine was used. Ninety-seven percent of patients had a successful block. Only one patient had severe discomfort during the block placement. The block lasted an average of 20 hours. During the first 24 hours after surgery, patients took an average of three hydrocodone tablets. Twenty-two of the 23 patients who had had previous major foot or ankle surgery found that the block was better than their previous pain control regimen. No patient had complications related to the block and 95% were satisfied and would have the block again.

Role of Metatarsus Primus Elevatus in the Pathogenesis of Hallux Rigidus

Metatarsus primus elevatus has been suggested as a primary causative factor in the pathogenesis of hallux rigidus. The purpose of this investigation was to define the role of elevation of the first ray in the pathogenesis of hallux rigidus by comparing patients with known hallux rigidus with a control population. We reviewed 264 lateral weightbearing radiographs from 81 patients with hallux rigidus, 50 asymptomatic volunteers, and 64 patients diagnosed with isolated Mortons neuroma. Results revealed that the mean values for elevation of the first ray in patients with mild or moderate hallux rigidus were nearly identical to those in the control group. Patients with advanced radiographic hallux rigidus had a slightly higher mean value for metatarsus primus elevatus. An average of nearly 8 mm of metatarsus primus elevatus is a normal finding in patients with hallux rigidus as well as in normal subjects. This investigation did not address the clinical outcome or biomechanical effects of a plantarflexion osteotomy of the first ray. However, on the basis of the finding that first ray elevation is normal, it seems unlikely that a plantarflexion osteotomy would have a role in the treatment of hallux rigidus.

Epiphysiodesis of the lower extremity : results of the percutaneous technique

The results of 42 percutaneous epiphysiodeses of the lower extremity in 26 patients are reported. All patients achieved physeal arrest radiographically and clinically. No patient developed angular deformity from incomplete arrest. No neurovascular complications or fractures occurred. The average hospital stay for patients undergoing epiphysiodesis alone was 1 day. Percutaneous epiphysiodesis of the lower extremity provides a reliable and safe technique for growth plate arrest. The advantages of this technique include a cosmetic scar, short hospital stay, low incidence of complications, and reliable physeal arrest.

Role of the Peroneal Tendons in the Production of the Deformed Foot with Posterior Tibial Tendon Deficiency

Ten patients were identified with traumatic, complete common peroneal nerve palsy, with no previous foot or ankle surgery or trauma distal to the knee, who had undergone anterior transfer of the posterior tibial tendon to the midfoot. Six of these patients had a transfer to the midfoot and four had a Bridle procedure with tenodesis of half of the posterior tibial tendon to the peroneus longus tendon. Average follow-up was 74.9 months (range, 18–351 months). All patients] feet were compared assessing residual muscle strength, the longitudinal arch, and motion at the ankle, subtalar, and Choparts joint. Weightbearing lateral X-rays and Harris mat studies were done on both feet. In no case was any valgus hindfoot deformity associated with posterior tibial tendon rupture found. It seems that the pathologic condition associated with a posterior tibial tendon deficient foot will not manifest itself if peroneus brevis function is absent.

Effect of Calcaneal Osteotomy and Lateral Column Lengthening on the Plantar Fascia: A Biomechanical Investigation

Medial calcaneal displacement osteotomy or lateral column lengthening fusion has been advocated to augment tendon transfer in planovalgus foot deformity associated with chronic posterior tibial tendon insufficiency. It is hypothesized that plantar fascia tightening occurs with these procedures, helping to restore a more normal longitudinal arch. To investigate this further, nine fresh-frozen cadaver below-knee specimens were used. A flatfoot model was created by sectioning of the posterior tibial tendon, spring ligament, talonavicular capsule, and deltoid ligament. A liquid-metal strain gauge, calibrated to measure fractional changes in length, was sutured proximally to the origin and distally into the thickest portion of the medial band of the plantar fascia. Specimens were axially loaded to 400 N and plantar fascia strain was measured. Fractional length changes in the plantar fascia were then measured after a medial displacement calcaneal osteotomy and after a lateral column lengthening through the calcaneocuboid joint. Tightening of the plantar fascia did not occur with either medial calcaneal displacement or lateral column lengthening. The plantar fascia became significantly less taut with both medial displacement and lateral column lengthening. We found that lateral column lengthening produced significantly looser plantar fascia than did medial displacement of the calcaneal tuberosity.

Deformity correction and arthrodesis of the midfoot with a medial plate.

Nine feet in eight patients undergoing tarsometatarsal (Lisfranc) or other midfoot arthrodeses for posttraumatic or degenerative arthritis were reviewed retrospectively. All patients were treated using a medial one-third tubular plate spanning the midfoot joints to be fused. Three feet underwent fusion in situ while six feet underwent correction of residual planus, planovalgus, or cavovarus deformity at the time of fusion. All patients achieved fusion within 12 weeks. A good or excellent result was achieved in seven of nine feet. There was no radiographic or clinical evidence of pseudarthrosis or medial hardware failure in any patient. No patient to date has required hardware removal for a painful or prominent implant. The talus first metatarsal angle was improved an average of 15.5° in the lateral plane and 10° in the AP plane in patients undergoing deformity correction. The technique of using a medial plate for midfoot arthrodesis allows for reliable fusion in patients who require salvage for midfoot arthritis. This technique also allows for correction of deformity in patients with residual midfoot deformity.

Late Results of Subtalar Distraction Fusion

Between 1990 and 1994, 15 subtalar distraction fusions were performed on 14 patients for sequelae of calcaneus fractures. Twelve patients (13 feet) were available for a minimum 2-year follow-up and constituted the composition of this study. All patients complained of lateral ankle pain and had CT evidence of calcaneofibular abutment and radiographic evidence of loss of heel height preoperatively. The average age at time of surgery was 56 years (range, 23–81 years), and the average follow-up was 47 months (range, 25–75 months). The only change in surgical technique from that previously described was the use of a bone spreader rather than a femoral distractor for distraction of the subtalar joint. The average preoperative talocalcaneal angle improved from 27° (range, 19–37°) to 33° (range, 23–45°) postoperatively (P < 0.003). The mean talar declination angle improved from 11° (range, 6–18°) to 16° (range, 7–27°) postoperatively (P < 0.003). The mean heel height increased from 71 mm (range, 60–83 mm) to 76 mm (range, 63–91 mm) postoperatively (P < 0.0001). All patients completed the AOFAS Ankle-Hindfoot scale at latest follow-up, and the average score was 76.1 (range, 57–94). Eleven of 13 outcomes were rated as very satisfactory or satisfactory. Twelve of 13 said they would ‘definitely yes’ do surgery again. We have found that subtalar distraction fusion for late complications of calcaneus fracture in a carefully selected population can provide a consistent and satisfactory outcome.

Triple Arthrodesis with Lateral Column Lengthening for Treatment of Severe Planovalgus Deformity

Triple arthrodesis with lateral column lengthening through the calcaneocuboid joint was performed on 22 feet in 14 patients. The primary indication for surgery was severe symptomatic planovalgus deformity unresponsive to conservative measures. All patients achieved solid fusion within 12 weeks. No patient had a decline in ambulatory status. Excellent correction of deformity was achieved and maintained with an average correction of the talus first metatarsal angle of 25° in both the AP and lateral planes. Triple arthrodesis with lateral column lengthening provides for reliable arthrodesis and allows correction of severe planovalgus deformity while maintaining foot length.