Initial Presentation and Progression of Secondary Osteonecrosis of the Knee.

Background: Early detection and intervention are critical to maintaining the native articular cartilage before collapse in secondary osteonecrosis of the knee (SOK). We conducted a retrospective study documenting the initial stage of presentation and the progression of SOK.

Methods: Our database was reviewed for patients younger than 65 years of age diagnosed with atraumatic SOK between 2002 and 2018. Demographic data, plain radiographs as well as MRI at initial evaluation, and initial treatment were classified and analyzed.

Results: One hundred four patients with 164 knees were identified. Mean age was 39 ± 16 years. Females (64%) with bilateral disease (58%) predominated. Seventy-five percent of patients had a history of corticosteroid use, of which 41% were diagnosed with hematologic malignancy and lupus. Fifteen percent of patients had a history of ethanol abuse. At initial presentation, 55% of patients were diagnosed with Ficat-Arlet stage I/II, while 45% were diagnosed with Ficat-Arlet stage III/IV. We found a significant difference in the mean age of patients at early stage of SOK with corticosteroid use (31 ± 12 years of age) when compared to ethanol use (43 ± 13 years of age, P = .02). Treatments included observation (57%), joint preservation surgery (20%), and total knee arthroplasty (23%).

Conclusion: Nearly half of patients presented at late stage compromising the potential for joint preservation. The difference in age of referral by over a decade, based on etiology of SOK, suggests a strong provider-based referral or screening bias may be present. Hence, a multidisciplinary approach to earlier detection and referral may be a more effective strategy for preventing the progression of SOK.