Clinical outcomes after intra-operative 3D O-arm imaging assisted minimally invasive fixation of calcaneum fractures

Background: The calcaneus is the most fractured tarsal bone and plays an important role as part of the subtalar joint to transfer weight from the lower limb to the ground. Injury to this structure and alteration of weight bearing biomechanics can therefore be debilitating and result in poor functional outcomes. Surgical fixation which is often indicated for displaced or intra-articular fractures is challenging due to the unique anatomy of the calcaneum. The use of intra-operative three-dimensional (3D) O-arm imaging confers advantages over traditional two-dimensional (2D) fluoroscopy which can lead to better outcomes. Less invasive approaches such as percutaneous screw fixation likewise offers benefits over conventional open surgery such as reduced risk of wound complications. This paper aims to report the clinical outcomes after intra-operative 3D O-arm imaging assisted MIS fixation of calcaneum fractures. Methods and materials: All patients in our institution who underwent 3D O-arm imaging assisted minimally invasive screw fixation for calcaneal fractures were identified via manual chart review. Patients who suffered concomitant injuries to the operated limb, had open fractures, or were lost to follow up were excluded from this study. Patients were followed up for a minimum duration of two years. Patients were assessed with SF-36, Visual Analogue Score (VAS) and AOFAS Hindfoot Score at final follow up. Results: A total of 5 patients were included in our study, all of them were male with a mean age of 34.6 ± 12.3 years (range 23–53 years), with a mean follow up duration 21.4 months (range 20–23 months). Mean SF-36 subscale scores were PF 91 ± 10.8, RP 70 ± 32.6, RE 66.7 ± 40.8, VT 75 ± 20, MH 88 ± 11.7, SF 87.5 ± 21.7, BP 76 ± 21.3 and GH 84 ± 16.4; mean VAS was 0.6 ± 0.9 (range 0–2) and mean AOFAS was 86.4 ± 12.3 (range 65–94) at final follow-up. Conclusion: 3D O-arm assisted minimally invasive surgery for calcaneal fractures with percutaneous cannulated screws show good outcomes at 2 year follow up. The use of 3D imaging intra-operatively along with a minimally invasive approaches allows immediate revision intra-operatively which reduces the rate of revision surgery and associated costs, and reduces the risk of wound complications. Level of evidence: Level IV.