Clinical study on arthroscopic reduction and internal fixation for malunion and nonunion talus fractures classified as type II by Zwipp

OBJECTIVE: To investigate the surgical method of arthroscopic reduction and internal fixation (ARIF) for malunion and nonunion of type II talus fracture according to the Zwipp classification, and to evaluate its therapeutic effect. METHODS: A retrospective analysis was performed on eight patients (five males and three females) with unilateral talus fracture treated with ARIF for malunion or nonunion at our hospital between July 2014 and July 2022. Patients’ age ranged from 17 to 55 years, with an average of 34.9 ± 12.3 years. Among them, five had talar body fractures and three had talar neck fractures. The interval between the initial fracture and the surgery was 11.1 ± 2.5 months (range, 8–16 months). According to the Zwipp’s classification of talus fracture malunion and nonunion, all eight cases were classified as type II. Intraoperative autologous iliac bone grafting was performed in all patients. At the final follow-up, the ankle joint range of motion and X-ray examination were assessed. Ankle joint function was evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale, and pain was evaluated using the visual analog scale (VAS). The preoperative AOFAS score was 38.4 ± 6.1 and the VAS score was 4.5 ± 0.9. RESULTS: All eight patients underwent follow-up for an average of 30.2 ± 14.2 months (range, 10–52 months). All patients achieved primary wound healing, and 2 experienced Achilles tendon contracture. No cases of avascular necrosis of the talus, fracture nonunion, infection, or other complications were observed. The AOFAS score at the last follow-up was 89.8 ± 3.8, with four cases rated as “Excellent” and four as “Good”. The VAS score was 1.4 ± 0.5. Both scores showed significant improvement compared with preoperative values (t=-28.826, P < 0.001; t = 8.919, P < 0.001). The complication rate was 25% (2/8, Achilles tendon contracture). CONCLUSION: ARIF is a potentially safe and effective surgical method for treating malunion and nonunion of type II talus fractures according to the Zwipp classification, offering minimal secondary damage to the talar blood supply, fewer postoperative complications, and faster recovery. However, these findings should be interpreted with caution due to the study’s limitations, including the small sample size and retrospective design. LEVEL OF EVIDENCE: Level II.