SummaryBackgroundOsteochondral fracture (OCF) of the lateral femoral condyle has a low incidence and old OCF is even more rarely seen; it is difficult to differentiate from late osteochondritis dissecans (OCD).Case ReportIn this report, we present the case of a 20-year-old male patient with an old OCF of the lateral femoral condyle. The possible etiology of OCF is discussed, along with its clinical manifestation, diagnosis, and treatment. He underwent arthroscopically-assisted reduction and fixation with cannulated screws. Four months after the surgery, arthroscopy showed good osteochondral healing, and screws were removed. He had achieved good functional recovery by the follow-up visit.ConclusionsOld OCF should be distinguished from OCD in clinical practice, and osteochondral bodies should be preserved as much as possible. Osteochondral reduction and fixation under arthroscopy was minimal and the clinical effect was good.