Does immobilisation improve outcomes in proximal tibial stress fractures among military recruits?

Proximal tibial stress fractures (PTSFs) are a significant cause of morbidity in military recruits, often requiring prolonged rehabilitation and leading to attrition from training. Despite their impact, little data exist to guide optimal treatment strategies, and most recommendations are extrapolated from diaphyseal tibial stress fractures. This study aims to describe fracture characteristics, treatment protocols and outcomes of Marine Corps recruits diagnosed with PTSFs.

A retrospective review was conducted of Marine recruits at the Marine Corps Recruit Depot San Diego-an all-male training centre during the data collection period (2019-2021)-with MRI-confirmed PTSF. Patients who were initially treated non-operatively were included in this study. MRI and radiograph characteristics, age, bilateral or unilateral injury, treatment protocols (casting vs protected weight bearing) and outcomes-including return to full duty (RTFD) or separation-were evaluated. Statistical analyses included χ²testing, t-tests and logistic and linear regression modelling.

80 patients (105 total fractures) met inclusion criteria, with a mean age of 20 years. 25 patients had bilateral fractures. No patient initially treated non-operatively progressed to require surgery. PTSFs demonstrated a high likelihood of military separation, with over one in four eventually separating and an average time to disposition of 121 days. There were no statistically significant predictors of RTFD or ultimate disposition based on treating provider's specialty, casting or fracture characteristics. A trend towards decreased return to duty in bilateral fractures did not reach significance. Of the 21 separations, eight were directly attributable to the stress fracture.

In Marine recruits with PTSFs, conservative management without casting is safe and effective, even in bilateral cases or those with extensive fracture morphology. Outcomes were similar regardless of treating provider specialty. Casting offered no additional benefit and may be unnecessary in most cases.