Comparing the Cost Effectiveness of Locking vs Nonlocking Plates for Traumatic Ankle Fractures Using PROMIS Scores

Submission Type: Ankle Fractures Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: The choice between locking and nonlocking plates for the fixation of traumatic ankle fractures often involves a trade-off between cost and potential clinical outcomes. Locking plates are perceived to offer increased fixation stability, especially in osteopenic bone, due to the compression achieved through the screw-plate interface compared to the bone-plate interface. However, this benefit comes at the cost of a more expensive implant. Our study aims to evaluate the cost-effectiveness of these two fixation methods by comparing surgical costs, PROMIS (Patient-Reported Outcomes Measurement Information System) scores, and complication rates. Methods: A retrospective review was conducted on all patients who underwent fixation of ankle fractures at our institution from 2016 to 2021. Data on surgical costs and outcomes/complications were meticulously gathered through comprehensive chart reviews. PROMIS scores were systematically collected through structured telephonic interviews. Differences in PROMIS scores were analyzed using two-sided t-tests with Python version 3.11.4 and the SciPy library. Variations in complication rates were evaluated using Chi-square analysis with Python version 3.11.4 and the statsmodels library. Results: 283 patients underwent ankle fracture fixation with a locking plate. 210 patients underwent fixation with a nonlocking plate. The average cost of fixation with a locking plate was $3,094.90. Reoperations cost $1,807.63, with average OR time of 120 minutes valued at $7,440. The average cost of fixation with a nonlocking plate was $858. Reoperations cost $435.50, with an average OR time of 72 minutes valued at $4,464. PROMIS pain interference and physical function scores did not differ significantly. Complications occurred in 17% of patients with a locking plate and 23% of patients with a nonlocking plate (p = 0.10). Hardware removal (excluding plate removal) occurred more frequently in the nonlocking group (p < 0.001). Infection occurred more frequently in the locking group (p < 0.05). Conclusion: Our study demonstrates that while locking plates are significantly more expensive than nonlocking plates, there is no statistically significant evidence of their clinical superiority. Locking plates did, however, show a trend towards fewer overall complications. Locking plates were also removed significantly less frequently than the nonlocking plates, indicating that there may be greater irritation of local soft tissue and bone with the compression achieved through nonlocking plates, potentially justifying the higher cost associated with these plates.