Comparison of elective implant removal and complication rates between mini and small fragment implants for lateral malleolar fixation.

Introduction: Implant removal after open reduction and internal fixation (ORIF) of ankle fractures is common. Mini-fragment implants have gained popularity for their smaller size, with studies showing similar load to failure to small-fragment implants. We hypothesized mini-fragment implant use for ORIF of the distal fibula is associated with a lower implant removal rate and without an increase in implant failure.

Methods: In this retrospective review study at two level-one trauma centers, adult patients (>18 years) with a lateral malleolar or bimalleolar fracture were included. Chart review was performed to determine if patients received ORIF of the distal fibula with mini-fragment implants or small-fragment implants. The primary outcome was elective implant removal of the fibular plate. Secondary outcomes included complications requiring reoperation.

Results: Five-hundred and five patients were included with a mean age of 50.6 ± 17.8 years old with a mean follow-up of was 75.7 ± 61.0 weeks. Sixty patients (11.9 %) received mini-fragment fixation. The rate of elective distal fibula implant removal for the mini-fragment group was 8.3 % (5 of 60) compared to 10.8 % (48 of 445) in the small-fragment group (p = .66). The complication rate was 6.7 % (4 of 60) for the mini fragment group versus 6.5 % (29 of 445) for the small fragment group (p = 1.00). Logistic regression demonstrated that each additional week of follow-up increased the implant removal rate with the observed odd ratio (OR) of 1.007 (95 % CI 1.002-1.012).

Conclusion: Elective implant removal rates and complications requiring reoperation were similar between mini-fragment and small-fragment fixation of distal fibula fractures. The hypothetical benefit of low-profile mini-fragment implants should be balanced with the higher implant cost.