Synovial Inclusion Cyst Mimicking a Femoral Neck Stress Fracture in an Active Duty Servicemember

Abstract

Case: A 19-year-old female servicemember with history of ischiopubic rami stress fractures was referred to orthopaedic surgery for magnetic resonance imaging findings concerning for a tension-sided femoral neck stress fracture. However, her history and symptoms were discordant with the diagnosis of stress fracture. The patient was managed with protected weight-bearing for 6 weeks with gradual return to physical activity. Conclusion: Prophylactic surgical fixation is advocated for the management of tension-sided femoral neck stress fractures. However, surgeons should consider a broader differential diagnosis, to include a synovial inclusion cyst, when the clinical presentation is not consistent with a stress fracture.

Femoral Neck Stress Fractures in Athletes and the Military

“…Coxa vara alignment has been shown to increase the risk of FNSF by concentrating mechanical forces about the femoral neck [18][19][20] . Furthermore, femoroacetabular impingement can cause microtrauma to the femoral neck that could propagate into an overt fracture if subjected to increased load 5,21 . Com-promised proximal femoral structural integrity due to underlying systemic diseases or metabolic disorders can further increase the risk of FNSF development 2,22 .…”