We retrospectively reviewed all 92 patients (94 ankles) treated with a uniform technique of ankle arthrodesis using internal fixation with four screws between January 1, 1994, and December 31, 2000. We included only patients who underwent isolated ankle arthrodesis. We excluded patients who underwent additional fusion of the subtalar and/or talonavicular joints, patients treated with external fixation because of critical soft tissue conditions or underlying infection, and patients with mild degree osteoarthritis after malunited malleolar fractures treated with joint-preserving corrective osteotomies. Mean patient age at the time of surgery was 53 years (range, 34–69 years). Eighty-three of the 92 patients (90%) were treated for posttraumatic arthritis of the ankle. In all patients, nonoperative measures, such as alteration of activity or shoe wear, pain medication, and physical therapy, had failed for a minimum of 6 months prior to surgery. Twelve of the 92 patients had moved to an unknown address and eight declined to attend followup examination because they had moved to distant locations. Thus, 72 patients (72 ankles) were available for followup at a minimum of 4.8 years (average, 5.9 years; range, 4.8–7.8 years). Sixty-five of the 72 patients (90.3%) had posttraumatic arthritis, five had primary osteoarthritis (6.9%), and two patients had Charcot-Marie-Tooth disease (2.8%). Fifty-six of the 72 patients (77.8%) had initial malalignment of the talocrural axis with varus deformity greater than 5° in 47 patients, a valgus deformity greater than 10° in 10 patients, and equinus of more than 10° in nine patients.
All patients were evaluated by one of the authors (TE) pre- and postoperatively using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle/hindfoot scale [29
], and weight-bearing anteroposterior (with both feet in 20° of internal rotation) and lateral radiographs of both ankles. To evaluate the amount of axial deviation, a hindfoot alignment view [10
] of the lower leg was obtained and the hindfoot axis with respect to the tibia measured according to Saltzman and el-Khoury [40
]. The degree of arthritis at the ankle, subtalar, and talonavicular joints was documented by one of us (TE) using the radiographic scale provided by Bargon and Henkemeyer [3
] (Table ). Data on interobserver variability of this radiographic scale are not available. We performed CT scanning of the ankle and/or subtalar joint in all patients with radiographic evidence of subtalar or talonavicular arthritis at the time of initial presentation because this could influence the management plan, indicating necessity to fuse adjacent joints. We obtained MRI in cases of suspected necrosis after talar or pilon fractures to determine the subsequent need of bone grafting. In 35 patients with malunited malleolar fractures and only mild signs of posttraumatic arthritis (Bargon grade 0 to I), we performed an initial arthroscopy or arthrotomy of the ankle to evaluate the quality of weight-bearing cartilage. In 29 of these 35 patients viable cartilage was still present, therefore peritalar osteotomies or anatomic repair of a chronic unstable distal tibiofibular syndesmosis were preferred as joint-preserving procedures [31
]. These patients are not included in the present study.
Table 1 Radiographic grading of ankle arthrosis according to Bargon and Henkemeyer 
All patients underwent an ankle arthrodesis with débridement and fusion using the four-screw fusion technique, first described by the senior author (HZ [55
]). The patient was positioned supine with a thigh tourniquet that was inflated to between 200 and 300 mm Hg depending on the individual weight. We approached the ankle midline through a 6- to 8-cm-long longitudinal incision close to the medial border of the anterior tibial tendon (Fig. A–B). Care was taken to avoid injury to the medial dorsal cutaneous nerve, which may cross over the distal incision medially. We incised the proximal extensor retinaculum in a Z-shaped manner to allow easier reapproximation at the end of the operation. The anterior tibial artery and veins and the deep peroneal nerve were held away laterally with the extensor hallucis longus and extensor digitorum longus tendons (Fig. A–B). The anterior joint capsule and any existing osteophytes were resected. A generous débridement and removal of all sclerotic and nonviable bone was performed with osteotomes, curettes, and a rongeur. A midsized laminar spreader was placed between tibia and talus first laterally, then medially to allow complete débridement of the posterior aspect of the ankle, as well as the medial and lateral gutters. To determine adequate joint resection, we deflated the tourniquet at that time to ensure that a bleeding bone surface was exposed. Defects in 38 of 94 cases were grafted with autologous bone, especially in case of varus malposition of the talus or in the presence of avascular necrosis at the talar dome or lateral tibial plafond. A monocortical bone block was taken from the ipsilateral iliac crest and additional cancellous bone chips were interposed (Fig. A–B). In 21 cases of shortening of the distal tibia of more than 5 mm after correcting frontal malalignment, a shortening osteotomy of the distal fibula was performed to avoid calcaneofibular impingement. In 10 patients with marked equinus of more than 10° we performed percutaneous lengthening of the Achilles tendon to achieve correction. A roll of sheets below the distal tibia served as a fulcrum for forced reduction of the foot with respect to the tibial axis to avoid anteversion of the talus. The ankle was fixed temporarily with a 2.5-mm Kirschner wire (Fig. A–B). Proper positioning of the center of the talar body below the longitudinal axis of the tibia in both planes, correction of equines, and frontal (varus/valgus) malalignment were assessed fluoroscopically. The arthrodesis was fixed with four 6.5-mm cancellous lag screws as described previously [15
]. Two screws were inserted parallel from the anterior aspect of the distal tibia into the body of the talus (Fig. A–D). The third, mechanically most important, screw was inserted through a posteromedial stab incision approximately 3 cm proximal to the tip of the medial malleolus. The screw was inserted into the anterolateral portion of the talar head. The fourth screw was inserted percutaneously from the posterolateral aspect of the distal fibula approximately 1.5 cm proximal to the tip of the lateral malleolus into the dorsal portion of the talar body. In the presence of greater defects or osteopenic bone, fully threaded 6.5-mm screws were used. If a manifest syndesmotic instability was present at the time of fusion, a fifth screw was introduced as a tibiofibular set screw approximately 1.5 cm above and parallel to the tibial plafond. In four patients with a known or suspected allergy to components of surgical steel (cobalt, chromium, or nickel), we used titanium screws. Correct screw length and realignment of the ankle position was assessed by intraoperative anteroposterior and lateral radiographs of the ankle (Fig. A–D). The wound was closed in layers over a suction drain with reapproximation of the extensor retinaculum.
Fig. 1A–B (A) The ankle is approached through an anterior midline approach, 6 to 8 cm in length. (Reprinted with permission from Endres T, Grass R, Rammelt S, Zwipp H. Ankle arthrodesis with four cancellous lag screws [in German]. Oper Orthop Traumatol (more ...)
Fig. 2A–B (A) The joint is exposed between the anterior tibial and extensor hallucis longus tendons. (Reprinted with permission from Endres T, Grass R, Rammelt S, Zwipp H. Ankle arthrodesis with four cancellous lag screws [in German]. Oper Orthop Traumatol. 2005;17:345–360.) (more ...)
Fig. 3A–B (A) Preoperative varus malposition of the talus must be corrected. (B) This may necessitate the interposition of a monocortical bone graft. (Reprinted with permission from Endres T, Grass R, Rammelt S, Zwipp H. Ankle arthrodesis with four cancellous lag (more ...)
Fig. 4A–B (A) Anterior translation of the talus is regularly found. (B) It must be corrected intraoperatively by shifting the talar center back into the longitudinal axis of the tibia. The position is held temporarily with a 2.5-mm Kirschner wire and controlled (more ...)
Fig. 5A–D (A) Fixation of the arthrodesis is achieved with four-screws. (Reprinted with permission and ©Springer from Fig. A in Zwipp H, Grass R, Rammelt S, Dahlen C. Arthrodese—Pseudarthrosen am Sprunggelenk. Die fehlgeschlagene Arthrodese (more ...)
Fig. 6A–D A 57 year old patient presented with idiopathic ankle arthritis and gradually developing pain and malalignment. (A) The preoperative radiographs show a severe varus malposition in the coronal plane and (B) a considerable anterior translation of (more ...)
The postoperative management aimed at early functional rehabilitation. The suction drain was typically removed after 2 days. Active and passive motion of the subtalar and midtarsal joints was begun on the second postoperative day while temporarily removing the cast. A split short-leg cast was applied for the period of wound healing only, typically 5 to 9 days. Following that time, 60 of 92 patients were treated postoperatively with an arthrodesis boot with rigid medial and lateral struts and a flexible sole (Variostabil®, Adidas, Herzogenaurach, Germany) allowing early full weight bearing as tolerated, usually after 2 to 3 weeks; otherwise, partial weightbearing of 20 kg was recommended for 6 to 8 weeks, the longer period being necessary after bone grafting. Ten patients were treated with partial weightbearing of 20 kg in their regular shoes. Twenty-two patients were placed in a short-leg cast for 6 weeks with partial weight bearing because of osteopenic bone quality or extensive bone grafting. Weightbearing was increased gradually after removal of the cast. All patients were given daily injections of low-molecular-weight heparin (eg, dalteparin, enoxaparin) until full weight bearing was achieved.
Patients were routinely seen at 6 weeks, and at 3, 6, and 12 months postoperatively for a complete physical examination, to assess bony union and determine weight-bearing status individually as detailed above. Union was verified by obliteration of the joint space and trabecular continuity from the tibia to the talus on lateral and anteroposterior weight-bearing radiographs of the ankle.
Nonunion was defined as radiographic evidence of incomplete fusion more than 9 months after surgery. All postoperative complications were noted. We defined major complications as deep soft tissue infection, osteomyelitis, and malunion or nonunion. Minor complications included superficial wound dehiscence, wound edge necrosis, or hematoma without signs of infection.
At final followup, patients were examined clinically for alignment and range of motion in the midtarsal (Chopart) joint. The functional results were evaluated by one of the authors (TE) with the AOFAS ankle/hindfoot scale [29
]. Anteroposterior and lateral weight-bearing radiographs of the ankle and a hindfoot alignment view of the lower leg [10
] were obtained to evaluate bone healing, the amount of arthritis in the adjacent joints as graded on the Bargon scale [3
], and tibiotalar alignment. We measured sagittal motion at the midtarsal joint with lateral radiographs with the foot in dorsiflexion and plantarflexion (Fig. A−J).
Fig. 7A–J A 44-year-old woman presented with severe posttraumatic arthritis 2 years after an operatively treated trimalleolar fracture-dislocation. On preoperative radiographs she had (A) varus malunion of the talus with (B) anterior translation. (C) The (more ...)