RESUMO
BACKGROUND:Currently,there have been a variety of conservative and surgical treatment plans for spontaneous osteonecrosis of the knee,achieving excellent results.However,a broad consensus on indication and guide of surgical treatment has not been announced.In clinical practice,there is still a misunderstanding that unicondylar replacement or total knee arthroplasty should be performed upon the discovery of spontaneous osteonecrosis of the knee,while an urgent need for universal access to the concept of stepwise therapy. OBJECTIVE:To summarize and find the factors leading to the poor effect of conservative treatment in spontaneous osteonecrosis of the knee,which occurred on the medial femoral condyle,from the literature and clinical cases,at the same time,combined with the Koshino stage,to propose the strategy of stepwise spontaneous osteonecrosis of the knee treatment on the medial femoral condyle. METHODS:A systematic search of the literature database was conducted to summarize the factors leading to poor outcomes of conservative treatment in spontaneous osteonecrosis of the medial femoral condyle.Meanwhile,according to the Clinical&Health Records for analytics&Sharing system,the cases receiving conservative and surgical treatment in spontaneous osteonecrosis of the medial femoral condyle in the Department of Orthopedics of Guangdong Provincial Hospital of Chinese Medicine from January 2017 to January 2023 were analyzed retrospectively,then the causes of success and failure in typical cases were summarized and analyzed. RESULTS AND CONCLUSION:(1)Early diagnosis and treatment of spontaneous osteonecrosis of the knee were very important for prognosis.For sudden knee pain in some patients,if no obvious abnormality was found in the X-ray examination,and the symptoms persisted and could not be relieved for more than 1 week,an MRI examination was recommended to detect early spontaneous osteonecrosis of the knee.(2)The X-ray images of Koshino stage 1 and stage 2 of spontaneous osteonecrosis of the medial femoral condyle were difficult to be distinguished,which needed to be probed by MRI.MRI images of Koshino stage 1 were mainly characterized by bone marrow edema,and an osteonecrosis area with a clear boundary was not formed,while MR images of Koshino stage 2 showed a necrotic area with a clear boundary.(3)Five factors leading to the poor effect of conservative treatment on spontaneous osteonecrosis of the medial femoral condyle were summarized:a.The necrotic area was＞5 cm2;b.The necrotic area accounted for more than 40%of the condyle;c.relative compression percentage of medial meniscus≥33%(with or without medial meniscus injury and subchondral bone marrow edema);d.MRI depth of necrotic area(anterior-posterior diameter of sagittal necrotic area)＞20 mm;e.varus deformity of lower limb＞6°.(4)Conservative treatment of spontaneous osteonecrosis of the knee in Koshino stage 1 was good.For spontaneous osteonecrosis of the knee in Koshino stage 2,conservative treatment was preferred or combined with drilling decompression.If there was no relief or improvement of symptoms or in MRI after 3 months,while the patient had any of the previous five factors,then knee preservation surgery should be considered.For spontaneous osteonecrosis of the knee in Koshino stage 3 and stage 4,knee preservation surgery should be selected based on the previous five factors,including age,gender and activity level of the patient.Total knee arthroplasty was used for spontaneous osteonecrosis in Koshino stage 4,which was associated with symptomatic patellofemoral arthritis,valgus alignment,or necrotic area,which greatly affected the stability of unicondyle prosthesis.