Can Knee Arthroscopy Be Considered Entirely Safe for Patients Over 50 Years Old With no Risk of Osteonecrosis? Case Series and Literature Review on Post-Artrhoscopy Osteonecrosis of the Knee (PAONK).

Objective: Although post-arthroscopy osteonecrosis of the knee is well-documented in the literature, its etiology and prognosis remain unclear. The purpose of this study is to present a group of individuals who experienced avascular necrosis following knee arthroscopy, to examine the factors leading to this condition and assess the outcomes of treatment, as well as to perform a literature review on the subject.

Methods: We retrospectively studied patients between January 2015 and March 2024 who had developed knee osteonecrosis following a standard arthroscopic procedure for treating meniscal tears. All adult patients with isolated meniscus tears and grade 2 or less chondral lesions were included. Patients with evidence of bone edema on MRI performed 4-6 weeks after the onset of preoperative symptoms were not included in the study. The Knee injury and Osteoarthritis Outcome Score (KOOS) was used as an outcome measure. A correlation analysis was performed to explore the degree of association between variables, with significance set at p < 0.05.

Results: Eight patients out of 974 arthroscopies met the inclusion criteria. There was one woman and seven men (mean age 57 [range: 51-71]). The lesions noted at arthroscopy included seven medial meniscus tears that were treated with excision and one lateral meniscal tear that was treated with suture repair and still developed osteonecrosis. None of them were traumatic while all patients had early degenerative changes in the compartment of interest.

Conclusions: Osteonecrosis should be suspected in older patients experiencing worsening symptoms following knee arthroscopy for degenerative meniscus tears and partial meniscectomy. Increased age, a higher BMI, and a delayed diagnosis appear to be associated with more severe disease progression and the need for operative treatment.