Locking versus nonlocking plates for the treatment of posterior malleolar ankle fractures: A retrospective cohort study and cost analysis.

Background: We hypothesized that, as posterior malleolar ankle fractures usually present one or two main fragments, the buttress plating principle can be successfully achieved either with conventional nonlocking or anatomic locking posterior tibia plates, and no clinical differences should be found. The aim of this study was to evaluate the outcomes of posterior malleolar ankle (PM) fractures treated with conventional nonlocking (CNP) or anatomic locking plates (ALP), and also to compare both constructs in terms of crude costs.

Methods: A retrospective cohort study was designed. CNP was used in 22 patients and ALP was used in 11 patients. American Orthopedic Foot and Ankle Society (AOFAS) score was registered at four weeks, 3-6 months, 12 and 24 months to assess all patients' functional status. The primary outcome was ankle and hindfoot AOFAS score at 12 months follow-up visit. All complications, radiographic evaluation and implant construct costs were also registered and compared. The average follow-up was 25.4 (range, 12-42) months.

Results: No significant difference was observed between both cohorts, in terms of AOFAS score and complication rate (P > .05). We found that ALP construct is 17 times more expensive than CNP construct in our institution (P < .001).

Conclusion: Anatomic locking posterior tibial plates may be an interesting device when poor bone quality is present or when a true multifragmentary pilon fracture is faced. Anatomic locking posterior tibia plate should not become a regular implant for any PM fracture since equivalent clinical and radiological results were obtained in our study using CNP with a significant reduced cost.