Lew C. Schon

Isolated Subtalar Arthrodesis

Background: The purposes of this retrospective study were to review the results of isolated subtalar arthrodesis in adults and to identify factors influencing the union rate. The hypotheses were that (1) the overall outcome is acceptable but is not as favorable as previously reported, (2) complication rates, especially the nonunion rate, are higher than previously reported, and (3) factors contributing to a less favorable union rate can be identified. Methods: Between January 1988 and July 1995, 184 consecutive isolated subtalar arthrodeses were performed in 174 adults (115 men and fifty-nine women) whose average age was forty-three years (range, eighteen to seventy-nine years). Eighty patients (46 percent) were smokers. The indications for the procedure included posttraumatic arthritis after a fracture of the calcaneus (109 feet), a fracture of the talus (thirteen feet), or a subtalar dislocation (thirteen feet); primary subtalar arthritis (thirteen feet); failure of a previous subtalar arthrodesis (twenty-eight feet); and residual congenital deformity (eight feet). Rigid internal fixation with one or two screws was used for all feet. Bone graft was used in 145 feet; the types of graft material included cancellous autograft (ninety-four feet), structural autograft (twenty-nine feet), cancellous allograft (seventeen feet), and structural allograft (five feet). Bone graft was not used in the remaining thirty-nine feet. Results: Clinical and radiographic follow-up examinations were performed for 148 (80 percent) of the 184 feet at an average of fifty-one months (range, twenty-four to 130 months) postoperatively. The average ankle-hindfoot score according to the modified scale of the American Orthopaedic Foot and Ankle Society (maximum possible score, 94 points) improved from 24 points preoperatively to 70 points at follow-up. Thirty feet had clinical evidence of nonunion. The union rate was 84 percent (154 of 184) overall, 86 percent (134 of 156) after primary arthrodesis, and 71 percent (twenty of twenty-eight) after revision arthrodesis. The union rate was 92 percent (ninety-three of 101 feet) for nonsmokers and 73 percent (sixty-one of eighty-three feet) for smokers (p < 0.05). Intraoperative inspection revealed that 42 percent (seventy-eight) of the 184 feet had evidence of more than two millimeters of avascular bone at the subtalar joint; all thirty nonunions occurred in this group (p < 0.05). A nonunion occurred in three of the five feet that had been treated with structural allograft and in two of the six feet in which the subtalar arthrodesis had been performed adjacent to the site of a previous ankle arthrodesis. After elimination of the subgroups of feet in patients who smoked, those that had had a failure of a previous subtalar arthrodesis, those that had been treated with a structural graft, and those that had had the subtalar arthrodesis adjacent to the site of a previous ankle arthrodesis, the union rate improved to 96 percent (seventy-three of seventy-six). Complications other than nonunion included prominent hardware requiring screw removal (thirty-six of 184 feet; 20 percent), lateral impingement (fifteen of 148 feet; 10 percent), symptomatic valgus malalignment (five of 148 feet; 3 percent), symptomatic varus malalignment (four of 148 feet; 3 percent), and infection (five of 184 feet; 3 percent). Conclusions: To the best of our knowledge, the present study includes the largest reported series of isolated subtalar arthrodeses in adults. Our results suggest that the outcome following isolated subtalar arthrodesis is not as favorable as has been reported in previous studies. The rate of union was significantly diminished by smoking, the presence of more than two millimeters of avascular bone at the arthrodesis site, and the failure of a previous subtalar arthrodesis (p < 0.05 for all). Other factors that probably affect the union rate include the use of structural allograft and performance of the arthrodesis adjacent to the site of a previous ankle arthrodesis.

Charcot neuroarthropathy of the foot and ankle.

The goal of this study was to characterize Charcot neuroarthropathy of the foot and ankle by specific sites of involvement (ankle, hindfoot, midfoot, and forefoot), modes of presentation, methods of management, and outcome. A summary of treatment and results for 50 ankles, 22 hindfeet, 131 midfeet, and 18 forefeet is presented. Nondisplaced neuropathic ankle fractures typically healed uneventfully with casting and bracing. For displaced ankle fractures, closed reduction and casting generally resulted in loss of reduction and progressive deterioration; better results were obtained with open reduction and internal fixation, using supplemental Kirschner wires and screws. Ankles with Charcot neuroarthropathy and preexisting arthritis typically required arthrodesis. Of the ankles with neuropathic avascular talar necrosis, approximately ⅓ did well with nonoperative intervention and ⅔ required surgery. Chronic, unstable, malaligned Charcot ankles often required arthrodesis. Neuropathic calcaneal fractures were managed successfully nonoperatively. For feet with transverse tarsal joint involvement (Schon Type IV), management was more complex. Nonoperative treatment was successful for less than ½. Two thirds of the feet with midtarsus involvement (Schon Types I, II, and III) were managed successfully nonoperatively; ⅓ required surgery for recurrent ulceration, instability, or osteomyelitis. Half of the feet with forefoot neuroarthropathy required surgery for malalignment, ulceration, and/or difficulty with shoewear or braces. This review has established patterns of Charcot involvement of the foot and ankle with corresponding methods of treatment and subsequent responses. From this extensive clinical experience with 221 neuropathic fractures or Charcot joints, recommendations were derived to assist in selecting appropriate management options.

Treatment of Stage II Posterior Tibial Tendon Deficiency With Flexor Digitorum Longus Tendon Transfer and Calcaneal Osteotomy

Background: To assess the efficacy of surgical correction of stage II tibial tendon deficiency with medial translational calcaneus osteotomy and flexor digitorum longus tendon transfer to the navicular, the authors retrospectively reviewed results of treatment of stage II posterior tibial tendon deficiency in 129 patients for whom surgery was performed between 1990 and 1997. Methods: The indication for surgery included tendon weakness, flexible deformity, and foot pain refractory to nonsurgical treatment. All patients had a painful flexible flatfoot without fixed forefoot supination deformity (stage II). A medial translational osteotomy of the calcaneus and transfer of the flexor digitorum longus tendon into the navicular were done. The patients were examined, radiographs were obtained, and isokinetic evaluation of both feet was performed at a mean of 5.2 years postoperatively. The American Orthopaedic Foot and Ankle Society (AOFAS) Hindfoot Scale and Short Form Health Surgery (SF-36) were used to evaluate patients postoperatively. Results: The mean AOFAS score at follow-up was 79 points (range, 54-93). There were seven significant complications in six patients. Isokinetic inversion and plantarflexion power and strength were symmetric with the contralateral limb in 95 patients, mildly weak in 18 patients, and moderately weak in eight patients. Subtalar joint motion was normal in 56 (44%), slightly decreased in 66 (51%), and moderately decreased in seven patients (5%). Correction was significant (p <.05) in all four radiographic parameters evaluated. Patients were entirely satisfied (118 patients), partially satisfied (seven patients), or dissatisfied (four patients). Further, 125 (97%) experienced pain relief, 121 (94%) showed improvement of function, 112 (87%) experienced improvement in the arch of the foot, and 108 (84%) were able to wear shoes comfortably without shoe modifications or orthotic arch support. Conclusions: The surgical correction of stage II posterior tibial tendon deficiency with medial translational calcaneus osteotomy and flexor digitorum longus tendon transfer to the navicular yielded excellent results with minimal complications and a high patient satisfaction rate.

Clinical Outcome After Primary Triple Arthrodesis

Background: To analyze the effects of multiple preoperative, intraoperative, and postoperative factors on the intermediate results of triple arthrodesis, we focused on preoperative deformity, preoperative diagnosis, degree of clinical and radiographic correction, and arthritis of the ankle. Methods: Between 1987 and 1995, 160 patients were managed with a total of 183 triple arthrodeses. Patients who had an infection or neuroarthropathy or who were managed with a revision arthrodesis were excluded from our study. Of the 160 patients, 111 (132 feet) who had been followed for a minimum of two years formed our study group. Each patient had an arthrodesis with rigid screw fixation and realignment of the joint surfaces without resection of wedges. The average duration of follow-up was 5.7 years (range, 2.0 to 10.8 years). Results: As seen radiographically, arthritis of the ankle was significantly more severe postoperatively than preoperatively (p < 0.01), although patient satisfaction was not associated with the presence of arthritis. On a scale (not a visual analog) of 0 (not satisfied) to 10 (completely satisfied), overall satisfaction averaged 8.3 points (range, 0 to 10 points). The postoperative modified ankle-hindfoot score of the American Orthopaedic Foot and Ankle Society averaged 60.7 points (range, 0 to 94 points). There was a significant association (p = 0.001) between satisfaction of the patient and postoperative alignment. Ten patients had a total of eleven complications: four superficial wound problems, three nonunions, one case of superficial peroneal neuritis, one case of Charcot-like neuroarthropathy of the foot (in a patient in whom diabetes developed during the follow-up period), one rupture of the Achilles tendon, and one case of peroneal tenosynovitis. Of the 111 patients, 101 (91 percent) stated that they would have the procedure again under similar circumstances, and this response was independent of the preoperative diagnostic or deformity group. Conclusions: Triple arthrodesis for the treatment of various deformities and etiologies is effective in relieving pain and improving functional deficits. Although a high prevalence of subsequent arthritis of the ankle was noted clinically and radiographically, we could detect no association between satisfaction of the patient and arthritis.

Six first metatarsal shaft osteotomies: mechanical and immobilization comparisons.

Because malunion (usually with dorsal elevation of the first metatarsal) has been reported after the treatment of severe hallux valgus deformities by proximal osteotomies, the current study was designed to compare the sagittal stability of six different metatarsal shaft osteotomies: the proximal crescentic, proximal chevron, Mau, Scarf, Ludloff, and biplanar closing wedge osteotomies. A plate was used in the biplanar closing wedge osteotomy; all others used screws for fixation. Ten fresh-frozen, human anatomic lower extremity specimens were used for each osteotomy. Failure loads were measured as units of force (newtons) and converted to pressure (kilopascals). Then the F-Scan system, which uses a thin insole to measure plantar pressure, was used to evaluate the pressure under the first metatarsal of seven volunteers using four types of shoes. According to the results, in patients with normal bone stock who are compliant, any of the four shoe types tested may be used after a Ludloff, Scarf, biplanar wedge (plantar screw fixation), or Mau osteotomy, but the wedge-based shoe should be used after a proximal crescentic or chevron osteotomy or for patients with severe osteopenic bone.

Intramedullary rod fixation compared with blade-plate-and-screw fixation for tibiotalocalcaneal arthrodesis: a biomechanical investigation.

BACKGROUND Achieving stable fixation when performing tibiotalocalcaneal arthrodesis can be challenging, especially in osteopenic bone. The purpose of the current investigation was to compare the stiffness and fatigue endurance of blade-plate-and-screw fixation with intramedullary rod fixation in a cadaveric model. METHODS In ten matched pairs of fresh-frozen cadaveric legs, a tibiotalocalcaneal arthrodesis was performed with use of a blade-plate and a 6.5-mm sagittal screw in one leg and with use of an intramedullary rod in the contralateral leg. After an initial load-deformation curve was obtained, each specimen was loaded to 270 N through 250,000 cycles at a rate of 3 Hz. RESULTS Blade-plate-and-screw fixation resulted in significantly higher mean initial and final stiffness and decreased plastic deformation than did intramedullary rod fixation. In addition, there was an inverse correlation between bone-mineral density and the difference in plastic deformation noted between the specimens of each pair. CONCLUSIONS Blade-plate fixation is biomechanically superior to intramedullary fixation for tibiotalocalcaneal arthrodesis.

Result of Arthrodesis of the Hallux Metatarsophalangeal Joint Using Bone Graft for Restoration of Length

We treated 24 patients (18 women, six men; average age, 46.4 years; (range, 28 to 66 years) with fusion of the hallux metatarsophalangeal (MTP) joint using bone graft for the restoration of the length of the first ray. This procedure was performed after bone loss subsequent to previous surgeries for the correction of hallux valgus and hallux rigidus with: silastic arthroplasty (11), bunionectomy and distal metatarsal osteotomy (six), Keller resection arthroplasty (five), and total joint replacement (two). The indication for performing the arthrodesis with bone graft was a short first metatarsal, and associated metatarsalgia of the lesser metatarsals in addition to a painful MTP joint with or without deformity. This bone loss was associated with avascular necrosis of the first metatarsal (nine patients) and with osteomyelitis (seven patients). Of the 24 patients, 14 underwent additional concurrent surgery for correction of hammer toes (10), excision of a Mortons neuroma (two), and lesser metatarsal osteotomy (two). All patients were examined clinically and radiographically at a mean interval of 62.7 months after surgery (range, 26 to 108 months). The patients were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) hallux and MTP 100-point outcome scale. Arthrodesis occurred in 19/24 patients (79.1%) at a mean of 13.3 weeks (range, 11 to 16 weeks), and the first ray was lengthened by a mean of 13 mm (range, 0 to 29 mm). Of the five nonunions, two were asymptomatic, and three were subsequently revised successfully, with arthrodesis occurring at a mean of 10.7 weeks. Complications included one deep infection requiring intravenous antibiotics for treatment of osteomyelitis and two minor superficial wound infections. The mean AOFAS score improved from 39 points (range, 22 to 60 points) to 79 points (range, 64 to 90 points). All patients were satisfied with the final outcome of treatment and stated that they would undergo the surgical procedure again. We concluded that arthrodesis of the hallux MTP joint with bone graft to restore bone loss and length of the first ray may be a worthwhile procedure despite the technical difficulty and the high rate of nonunion.

Midfoot Fusion Technique for Neuroarthropathic Feet: Biomechanical Analysis and Rationale:

To test the hypothesis that a plate applied to the plantar (tension) side of the medial midfoot provides stronger fixation than midfoot fusion with screw fixation, we biomechanically compared the two constructs for midfoot fusion. We created a model of midfoot instability in eight matched pairs of cadaver legs by section of joint capsule, ligaments, and tendons about Lisfrancs joints, and then performed a load-to-failure study to compare the fixation provided by a plantarly applied third tubular plate with that by cortical screws. After an initial load deformation curve to 1000 N was obtained, specimens were cyclicly loaded at 200 to 750 N for 3000 cycles and then loaded to failure (screw pullout, fracture, or deformation >3 mm). Comparing the plantar plate and midfoot fusion with screw fixation constructs, a plate applied to the plantar (tension) aspect of the medial midfoot provides a stronger, sturdier construct than does midfoot fusion with screw fixation.

Thromboembolism after foot and ankle surgery : A multicenter study

Thromboembolic disease presents a potentially fatal complication to patients undergoing orthopaedic surgery. Although the incidence after hip and knee surgery has been studied and documented, its incidence after surgery of the foot and ankle is unknown. For this reason, a prospective multicenter study was undertaken to identify patients with clinically evident thromboembolic disease to evaluate potential risk factors. Two thousand seven hundred thirty-three patients were evaluated for preoperative risk factors and postoperative thromboembolic events. There were six clinically significant thromboembolic events, including four nonfatal pulmonary emboli, after foot and ankle surgery. The incidence of deep vein thrombosis was six of 2733 (0.22%) and that of nonfatal pulmonary emboli was four of 2733 (0.15%). Factors found to correlate with an increased incidence of deep vein thrombosis were nonweightbearing status and immobilization after surgery. On the basis of these results, routine prophylaxis for thromboembolic disease after foot and ankle surgery probably is not warranted.

Clinical Results with the Ludloff Osteotomy for Correction of Adult Hallux Valgus

Background: Biomechanically, the Ludloff osteotomy fixed with lag screw compression has been shown to be more rigid than proximal crescentic and other proximal first metatarsal osteotomies for correction of symptomatic hallux valgus with a moderate to severe increase in the first intermetatarsal angle. The Ludloff osteotomy may, therefore, have a lower incidence of dorsal malunion and transfer metatarsalgia than other proximal first metatarsal osteotomies, such as the crescentic or chevron. Methods: We reviewed the results of 82 consecutive cases of moderate to severe hallux valgus deformities corrected with the Ludloff oblique metaphyseal-diaphyseal osteotomy of the first metatarsal combined with a distal soft-tissue procedure and medial eminence resection. Results: Follow-up was possible in 70 cases (85%) at an average of 30 months (range, 18 to 42 months). Preoperatively, the mean hallux valgus and first intermetatarsal angles were 31 degrees and 16 degrees, respectively. Postoperatively, these values improved to an average of 11 degrees and 7 degrees. In the sagittal plane, the first metatarsal was plantarflexed by an average of 1 mm, and there were no symptomatic transfer lesions of the second metatarsal. The mean AOFAS hindfoot score improved from 54 to 91 points. Complications included prominent hardware requiring removal (5), hallux varus (4), delayed union (3), superficial infection (3), and neuralgia (3). Conclusions: The use of the Ludloff oblique first metatarsal osteotomy resulted in excellent correction of the first intermetatarsal angle in patients with moderate to severe hallux valgus. With the plane of the osteotomy and rigidity of fixation, immediate ambulation was possible with minimal risk of dorsiflexion malunion of the first metatarsal.