Differentiating giant cell tumor of bone from patellofemoral syndrome: a case study

Balancing the assessment of musculoskeletal dysfunctions with a high level of suspicion for non-mechanical origins can be a challenge for the clinician examining a sports injury. Without timely diagnosis, non-mechanical complaints could result in surgery or loss of limb. This case describes the discovery of a Giant Cell Tumor of Bone (GCTB) following the re-evaluation of an athlete who had undergone five years of conservative management for patellofemoral pain syndrome (PFPS). Knee injuries account for 32.6% of sports injuries with PFPS being the most common and most likely diagnosis for anterior knee pain. GCTB is a benign aggressive bone tumor with a predilection for the juxta-articular region of the knee, comprising up to 23% of all benign bone tumors, and commonly occurs in the second to fourth decades. This case report illustrates the difficulty in accurately diagnosing healthy athletes, reviews common differentials for knee complaints and explores helpful diagnostic procedures.