回顾诊断为膝关节自发性骨坏死(SONK)并进行治疗的患者，描述不同影像学表现的患者的手术转化率及预后情况。

回顾性分析2013年1月到2022年2月在福建医科大学附属第一医院就诊，并诊断为SONK的患者，记录并分析患者的性别、年龄、身体质量指数(BMI)、X线Koshino分级、MRI的Sayyid分级、半月板情况(是否突出或撕裂)。记录其治疗方案，随访结局，并描述可能影响其手术转化率的因素。

共纳入61例患者，男性8例，女性53例，年龄(67±9)岁，BMI值为(25±4)kg/m²。发病部位：涉及股骨内侧髁86.9%，涉及内侧胫骨平台1.6%，涉及股骨内侧髁和内侧胫骨平台1.5%。有内侧半月板后角根部撕裂存在的有62.3%。内侧半月板突出程度测量结果为：轻度26.2%，中度54.1%，重度19.7%。X线Koshino分级为1~2级的病例20例，采取保守治疗后，有13例最终手术治疗，6例治愈，1例好转；3~4级的41例患者均转化为手术治疗。MRI的Sayyid分级为1~2级的病例12例，采取保守治疗后，有5例最终手术治疗，6例治愈，1例好转；MRI表现为3~4级的有49例，均行手术治疗。

诊断为SONK的患者中存在一部分膝关节软骨下不全骨折(SIFK)，通过MRI识别SIFK并及时限制负重可能使一部分患者避免手术干预。

To evaluate patients diagnosed with subchondral insufficiency fractures of knee (SONK) and undergo treatment, and describe the surgical conversion rate and prognosis of patients with different imaging manifestations.

Patients who were diagnosed as SONK in the First Affiliated Hospital of Fujian Medical University from January 2013 to February 2022 were retrospectively analyzed. The sex, age, (body mass index, BMI), X-ray Koshino grade, Sayyid grade of MRI and meniscus condition (whether protruding or torn) were recorded and analyzed. The treatment and outcome were recorded, and describe factors that may affect their surgical conversion rate.

A total of 61 patients were included, including eight males and 53 females, with an average age of (67±9) years. The average of BMI was (25±4)kg/m². The site of the disease: 86.9% involved the medial femoral condyle, 1.6% involved the medial tibial plateau, and 1.5% involved the medial femoral condyle and the medial tibial plateau. 62.3% of the patients had tears at the root of the posterior horn of the medial meniscus. The protruding degree of medial meniscus was measured as follows: mild was 26.2%, moderate was 54.1%, severe was 19.7%. In 20 cases of X-ray Koshino grade one and two, after conservative treatment, 13 cases were treated by operation, six cases were cured, one case improved. Forty-one cases of grade three to four were converted to operation. Of the 12 cases with MRI Sayyid grade one and two, five cases were treated by operation, six cases were cured, one case was improved, and 49 cases with MRI grade three to four were treated by operation.

Some patients of SONK may combine subchondral insufficiency fractures of knee (SIFK), so identifying SIFK by MRI and limiting weight bearing in time may prevent patients from surgical intervention.