Bilateral Sawtooth Grooving in the Patellofemoral Joints: A Unique Presentation of Degenerative Joint Disease

This report highlights the presence of interlocking bilateral longitudinal grooves, resembling cogwheels, between the lateral femoral condyles and patellar articular surfaces in a 93-year-old female cadaver. To facilitate a thorough assessment of the articular surfaces and internal structures, bilateral knee joint dissections were initiated by sectioning the quadriceps tendons and reflecting the patellae inferiorly. Photographic documentation was used to illustrate these cogwheel grooves in the left and right patellofemoral joints. Remarkably, the cogwheel grooves were more pronounced in the right knee compared to the left, predominantly affecting the lateral femoral condyles and trochlear fossa of both knees. This report presents a unique and under-documented manifestation of degenerative joint disease. While the precise etiology of this degenerative joint pathology remains elusive, repeated knee flexion and extension, as suggested by the cogwheel track pattern, combined with compromised bone integrity, played a role in shaping this unique topographical presentation. Given the limited access to patient history, the influence of concurrent erosive arthropathies or autoimmune processes remains uncertain. Reporting this case offers valuable insights into an infrequently observed manifestation of degenerative joint disease. It assists healthcare professionals in gaining a deeper understanding of the disease's progression, its severity, and indication for surgical intervention. To gain a more comprehensive understanding, future studies should expand by examining additional cadavers and conducting retrospective reviews of imaging studies. This should include the correlation of medical histories and demographic information with the occurrences of cogwheel grooves detected in the knee joint.