Abstract
RESEARCH TYPE: Level 4 – Case series INTRODUCTION/PURPOSE: The modified Lapidus procedure is a common surgical treatment for hallux valgus, particularly in patients with first tarsometatarsal (TMT) joint instability or arthritis. Although it provides reliable deformity correction, concerns remain about its long-term impact on adjacent midfoot joints. These joints may experience increased mechanical stress, potentially leading to degenerative changes and the need for further midfoot fusion surgery. Despite its widespread use, the risk of subsequent midfoot fusion remains unclear. This study evaluates the incidence of midfoot joints fusion following the Lapidus procedure using a national database. METHODS: A retrospective review was conducted using (PearlDiver) to identify patients who underwent Lapidus procedure (CPT 28297). Subsequent midfoot joint fusions were identified through the procedural codes ( 28740, 28730, 28735, 28737). To ensure continued enrollment, patients with verified insurance claims in the database for all of the subsequent 10 years were analyzed. Kaplan-Meier analysis was performed to determine the survivorship free of midfoot fusion over a 10-year follow-up period after Lapidus procedure. RESULTS: Among 6,594 patients verified as active in the database with at least 10 years of follow-up, 292 underwent subsequent further midfoot fusion, resulting in a 4.4% (95% confidence interval, 3.7% to 4.7%) incidence within the follow-up period. The average time between the Lapidus procedure and midfoot fusion was 2.7 years. Since CPT codes in the database do not specify laterality, a small number of cases may represent contralateral midfoot fusions, suggesting that the reported rate may slightly overestimate the true incidence. CONCLUSION: The 4.4% rate of subsequent midfoot fusion within 10 years highlights a measurable but relatively low risk of adjacent joint fusion following the modified Lapidus procedure. These findings provide valuable insights for surgeons counseling patients about long-term outcomes following Lapidus surgery.