Bilateral Sagittal Stress Fracture of Distal Femur Secondary to Osteoarthritis Knee: A Report on Unusual Case.

Abstract

Introduction: Stress fractures in the sagittal plane of the distal femur are rarely observed in clinical practice, particularly when occurring as a consequence of advanced knee osteoarthritis. This case report aims to highlight a rare presentation of sagittal plane stress fractures in the distal femur resulting from advanced knee osteoarthritis. It discusses the implications of this condition for both diagnosis and treatment, underscoring the need for heightened clinical awareness in patients with severe degenerative joint disease.

Case presentation: A 74-year-old female presented with bilateral osteoarthritis of knee Kellgren and Lawrence (KL) grade IV with a linear sagittal stress fracture of the distal femur. Unusual type of stress fracture was suspected on plane radiograph and confirmed on Magnetic Resonance Imaging (MRI). Bilateral total knee replacement was performed and screw augmentation was done for stress fracture. On one-year follow-up, patient was symptom-free, with no pain complaints. Knee range of motion was possible up to 0-100 degrees on the bilateral knee joint with no extensor lag.

Discussion and conclusion: Bilateral sagittal stress fractures of the distal femur secondary to osteoarthritis of the knee represent a rare but clinically significant pathology. Surgical intervention, by total knee replacement with adjunctive measures to stabilize the fractures, can effectively alleviate pain and improve functional outcomes in these patients.

Level of evidence: V.