Disclosures: Meghan K. Hayes, MD: No financial relationships or conflicts of interest

Case Diagnosis: Distal femoral physis stress fracture

Case Description: 16-year-old cross-county (5-minute mile) runner presented for evaluation of insidious onset, worsening left knee pain. The patient initially presented to an outside provider where an MRI was completed and he was diagnosed with bone marrow edema of the distal femoral metadiaphysis physis. He trialed a two-week period of rest with return to modified activity without improvement. Physical examination was significant for tenderness to palpation over the medial femoral condyle and medial joint line, poor balance with single leg stance, single leg squat with knee valgus movement, decreased hip abduction strength, pes planus, and significant heel strike predominance with running. He completed a successful 10-week graded return to sport program.

Setting: Outpatient Musculoskeletal ClinicAssessment/

Results: This patient presented with an uncommon distal femur physis stress fracture.

Discussion: A six-year epidemiologic study by Changstrom et al reviewed data from the High School Reporting Information Online and found stress fracture to be 0.8% of reported injuries amongst high school athletes. The most commonly reported stress fracture locations were the lower leg (40.3%), foot (34.9%), and lower back/lumbar spine/pelvis (15.2%). Stress fracture of the knee was reported to be 1.6%. The current case is an uncommon distal femur physis stress reaction/fracture in a male cross-country runner. The patient had multiple findings to suggest patellar maltracking and compression of his patella onto his femur as an uncommon factor that likely contributed to his stress fracture. The patient had knee valgus movement with functional testing, bilateral gluteus medius weakness, pes planus, and MRI findings suggestive of traction type injury in the distal patellar tendon insertion at the tibial tuberosity. These findings were used to tailor his physical therapy regiment and prevent further injury.

Conclusion: Distal femur physis stress fractures are uncommon and may require alternate target prevention strategies to address uncommon predisposing factors.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/an-uncommon-distal-femoral-physis-stress-fracture-in-a-high-school-cross-country-runner-a-case-report/