Mini-open arthroscopic-assisted calcaneal osteosynthesis (MACO): initial experience with severely comminuted intraarticular fractures

N. Patel, H. Zaw

Introduction: Percutaneous fixation of intraarticular calcaneal fractures adequately restore the subtalar joint with lower soft tissue complications and equivalent short-term results compared to open fixation. However, studies have largely focused on less severe fracture types (Sanders types 2/3). We report our initial experience of this relatively new Mini-open Arthroscopic-assisted Calcaneal Osteosynthesis (MACO) technique for more comminuted calcaneal fractures (Sanders types 3/4).

Methods: We prospectively studied consecutive patients with intraarticular calcaneal fractures requiring surgical fixation between April 2012 and June 2013. MACO involves initial subtalar arthroscopic debridement, with subsequent fluoroscopic-assisted, mini-open reduction and fixation of depressed fragments using cannulated screws. Outcome scores (Manchester-Oxford Foot(MOXFQ), AOFAS Hindfoot and SF-36 questionnaires) and radiological parameters were recorded with a mean follow-up of 12 months (7-13).

Results: There were 9 patients (7 M:2 F) with a mean age of 45.4 years (24-70). All had intra-articular joint depression-type fractures: 5 Sanders type 3 and 4 Sanders type 4. Mean time to surgery was 6.6 days (1-13), operating time was 89.4 minutes (66-130) and inpatient stay was 1.7 days (1-4). All wounds healed without complication and one patient required change of a long screw 11 days post-operatively. There were significant post-operative improvements in the mean Bohler’s angle (-2º[-27.2-14.8] to 30º[10.2-41.3], p< 0.0002) and angle of Gissane (95º[66.2-111.7] to 111º[101.6-120], p=0.004). Mean outcome scores were 60.8(41-86) for MOXFQ and 75.3(55-92) for AOFAS Hindfoot, with 55.9% developing moderate/severe subtalar joint stiffness. Mean physical and mental SF-36 summary scores were 35.5(24.5-41.5) and 51.7(40.8-61.7) respectively.

Conclusion: We describe the MACO technique for Sanders types 3/4 calcaneal fractures. There were no soft tissue complications with good short-term outcomes, despite a reduction in hindfoot mobility. Restoration of the joint and bone stock without infection is desirable in the event of subsequent arthrodesis. We propose MACO is a valuable alternative technique to open fixation.