Preoperative Risk Factors for Primary Metatarsophalangeal Arthroplasty Revision to MTP Arthrodesis for Hallux Rigidus

Background: Revision or conversion to arthrodesis following metatarsophalangeal (MTP) joint arthroplasty are salvage procedures to manage complications of MTP joint arthroplasty. The purpose of this study is to use a national administrative database to characterize nationwide trends of patients undergoing hallux MTP arthrodesis vs arthroplasty for hallux rigidus. Additionally, the authors sought to evaluate demographic trends and evaluate influence of patient-related risk factors in those undergoing MTP arthroplasty revision to arthrodesis. Methods: Patients who underwent MTP arthroplasty for diagnosis of hallux rigidus from 2010 to 2019 were identified in the Mariner subset of the PearlDiver database. Patients were included if they had undergone MTP arthroplasty for the diagnosis of hallux rigidus. Notably, the database lacks resolution about critical features of the arthroplasty design and materials. The revision cohort encompassed patients who underwent subsequent ipsilateral MTP arthrodesis or arthroplasty within 2 years of index arthroplasty procedure. Demographic characteristics and medical comorbidities were examined as potential patient-related risk factors for arthroplasty revision or revision to fusion. Univariate analyses were performed to analyze differences in patient demographics, comorbidities, and risk factors. A multivariate regression analysis was subsequently conducted to control for confounding variables. Results: 2750 patients underwent primary MTP arthroplasty for diagnosis of hallux rigidus. Of these, 44 (1.6%) underwent revision arthroplasty and 188 patients (6.8%) were revised to arthrodesis within the first 2 years after the index procedure. Multivariate regression analysis indicates that obesity (odds ratio [OR] 1.48, 95% CI 1.05-2.09), depression (OR 1.59, 95% CI 1.15-2.20), and steroid use (OR 2.94, 95% CI 1.30-6.65) were associated with a statistically significant increase in revision to arthrodesis from primary arthroplasty. Conclusion: Revision arthrodesis following primary MTP arthroplasty for hallux rigidus within 2 years was found to be a relatively common occurrence in this national insurance database study. Risk factors for revision arthroplasty to arthrodesis within 2 years of primary arthroplasty include obesity, depression, and steroid use. Level of Evidence: Level III, case-control study.