Percutaneous treatment of displaced intra-articular calcaneal fractures

A study cohort was retrospectively defined to include all patients with displaced intra-articular calcaneal fractures treated according to Forgon and Zadravecz5,6 over a 5-year period at our institution. Approval for the study was obtained from the Institutional Reviewing Board (IRB). Patients who died (n = 2), had a spinal cord lesion (n = 1), moved to a foreign country (n = 4), or whose addresses were unknown (n = 5) were excluded. After a follow-up period of at least 12 months (mean 35 months, range 13–75 months), patients were interviewed after informed consent was given and were evaluated for their functional outcome. Patients who had undergone secondary subtalar arthrodesis in the follow-up period were considered to have had a poor outcome for the primary surgery.

Surgical treatment according to the technique described by Forgon and Zadravecz5,6 with three minor modifications was carried out by three staff trauma surgeons. The patient was placed in the prone position and received spinal analgesia and antibiotic prophylaxis prior to the operation. Two fluoroscopes were installed to provide imaging in two orthogonal planes. Three 3-mm Kirschner wires were inserted from the lateral side through the calcaneal tuberosity, the cuboid, and the talar neck. The first modification concerned the placement of the distractors. These were positioned on both sides of the foot between the tuberosity of the calcaneus and talus and between the tuberosity and cuboid. Zadravecz et al. placed the latter between the cuboid and talus (Fig. 1). Through the distracting force generated between the three pins, the tuber angle of Böhler can be restored. The second modification concerned the insertion of a blunt drifter introduced from the plantar side to unlock and push up any remaining depressed parts of the subtalar joint surface of the calcaneus; Forgon and colleagues used pin leveraging from the lateral side to manipulate these fragments. The third modification was the discarding of the Böhler bone press to reduce the width of the fractured calcaneus. When an acceptable reduction was achieved, two Kirschner wires or two cancellous screws were inserted from the posterior aspect of the tuberosity. If necessary, a third screw was inserted from the lateral side of the calcaneus toward the sustentaculum tali to reduce bulging of the lateral wall. Postoperatively, patients remained non-weight-bearing for 3 months.

Patients completed three questionnaires: the Maryland foot score (MFS), the Creighton-Nebraska (CN) score, and the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score.8‐10 A modified visual analogue scale (VAS) was used to measure patient satisfaction on a scale of 1–10. Patients with a bilateral fracture completed the questionnaire for the foot with the most complaints and functional disability.6 For the purposes of comparison, the AOFAS scores were divided into the same groups used for the MFS: a score of 90–100 was graded as an excellent result; 75–89 as good; 50–74 as fair, and less than 49 points was graded as a failure.11,12 This differed slightly from the CN score, in which an excellent score is 90–100; good is 80–89; fair is 65–79, and poor is a score of less than 64 points.8

Physical assessments (walking ability on heels and toes, heel width, calf circumference, stability and alignment of the heel) were performed in the outpatient clinic by the investigator (TS). The ranges of motion of the ankle and the subtalar joint were measured according to the Association for Osteosynthesis (AO) neutral zero method. The subtalar range of motion was measured with patients sitting on their knees to measure only the subtalar joint motion.13 In patients with unilateral fractures, these measurements were compared with the values of the uninjured foot and ankle. In patients with bilateral fractures, standard normal values according to McMaster were used (inversion of 25° and 5° of eversion).14 The mean normal sagittal (flexion and extension) range of motion of the ankle joint was set at 60°.13

The preoperative radiographs and computed tomography (CT) scans were classified according to the classifications of Essex-Lopresti and Sanders, respectively, the latter without the use of subclasses.10,15 Immediately after the operation, radiographs in the lateral and axial plane were obtained to show the status of fracture reduction. At the time of inclusion in this study additional weight-bearing lateral, axial, and 45° inverted foot (Anthonson) views of the calcaneocuboid joint were obtained for both feet. The angles of Böhler and Gissane on preoperative and immediate postoperative radiographs were compared with the follow-up values and with normal values in patients with a unilateral fracture.15,16 The length, height, and width of the calcaneus were measured on the radiographs. The Zwipp score was used, in which the osteoarthrosis of the ankle joint, subtalar joint, and the calcaneocuboid joint, together with the difference in the Böhler’s angle were scored.17,18 A radiographic score of less than 6 points was considered a poor result, 7–8 points fair, 9–10 a good result, and 11–12 points an excellent result.18 All radiographs were evaluated together with a radiologist.