Thumb Carpometacarpal Arthritis: Prognostic Indicators and Timing of Further Intervention Following Corticosteroid Injection

Purpose: Corticosteroid injections are commonly used to treat thumb carpometacarpal arthritis in adults. We aimed to define the timing of surgery following an initial corticosteroid injection and identify patient-specific factors that influence the likelihood of repeat injection or surgery. Methods: We performed a retrospective analysis of all patients who underwent a first-time corticosteroid injection for carpometacarpal arthritis between 2009 and 2017. Demographic information, radiographic classification, additional nonsurgical therapies, complications, and outcomes were collected. Primary outcomes were repeat injection and surgical reconstruction. Kaplan-Meier survival analysis was used to characterize the timing of surgical intervention and Cox regression modeling was used to identify predictors of subsequent intervention. Results: Two-hundred thirty-nine patients (average age, 62.9 years) were identified, of which 141 (59.0%) had a repeat injection and 90 (37.6%) underwent surgery. There were no patient-specific characteristics associated with repeat injection. Eaton stage III/IV arthritis at initial presentation, current smoking status, and prior ipsilateral hand surgery were associated with an increased likelihood of surgery. By Kaplan-Meier analyses, 87.7% of patients who presented with Eaton III/IV arthritis did not have surgery within a year and 66.7% of these patients did not have surgery within 5 years. Conclusions: In this retrospective observational cohort study with 10-year follow-up from a 4-surgeon practice, advanced radiographic arthritis, current smoking status, and a history of ipsilateral hand surgery were patient-specific factors that predicted progression to surgery following injection. Of patients who presented with advanced radiographic arthritis, one-third underwent surgery within 5 years of initial injection. Although injection efficacy and causality cannot be inferred based on an observational longitudinal analysis, these data identify patient-specific factors that may have an impact on surgical decision-making and a potential timeframe for future intervention. Type of study/level of evidence: Prognostic IV.