Yasuda Tadashi, Ota Satoshi, Fujita Satoshi, Onishi Eijiro, Iwaki Koichi, Yamamoto Hiroshi
Department of Orthopaedic Surgery, Kobe City Medical Center General Hospital, Kobe, Japan.
Int J Rheum Dis. 2018 Dec;21(12):2104-2111. doi: 10.1111/1756-185X.13074. Epub 2017 Apr 5.
Medial meniscus tear has been proposed as a potential etiology of spontaneous osteonecrosis of the knee (SONK). Disruption of collagen fibers within the meniscus causes meniscal extrusion, which results in alteration in load distribution in the knee. Our purpose was to determine whether the extent of medial meniscus extrusion correlates with the severity of SONK in the medial femoral condyle.
Radiological stage of SONK and femorotibial angle (FTA) were determined on knee radiographs. Ellipsoid volume of SONK lesion and meniscal pathology (degeneration, tear and extrusion) were evaluated by magnetic resonance imaging.
All the 18 knees with SONK in the present study showed substantial extrusion (≥ 3 mm) and degeneration of the medial meniscus. The extent of meniscal extrusion and FTA were strongly associated with the stage and volume of the SONK lesion. Multiple linear regression analysis revealed that medial meniscus extrusion and FTA were useful predictors of the volume of the SONK lesion.
There was high association of medial meniscus extrusion and FTA with the radiological stage and volume of the SONK lesion. Increased loading in the medial femoral condyle with greater extrusion of medial meniscus and varus alignment may contribute to expansion and secondary osteoarthritic changes of a SONK lesion.
内侧半月板撕裂被认为是膝关节自发性骨坏死（SONK）的潜在病因。半月板内胶原纤维的破坏会导致半月板挤出，进而引起膝关节负荷分布的改变。我们的目的是确定内侧半月板挤出程度与股骨内侧髁SONK严重程度之间是否存在关联。
通过膝关节X线片确定SONK的放射学分期和股胫角（FTA）。通过磁共振成像评估SONK病变的椭球体体积和半月板病理情况（退变、撕裂和挤出）。
本研究中所有18例患有SONK的膝关节均显示内侧半月板有明显挤出（≥3mm）和退变。半月板挤出程度和FTA与SONK病变的分期和体积密切相关。多元线性回归分析显示，内侧半月板挤出和FTA是SONK病变体积的有效预测指标。
内侧半月板挤出和FTA与SONK病变的放射学分期和体积高度相关。随着内侧半月板挤出增加和内翻对线，股骨内侧髁负荷增加可能导致SONK病变扩大和继发性骨关节炎改变。
