Oda Shuhei, Fujita Akifumi, Moriuchi Hiromitsu, Okamoto Yoshinori, Otsuki Shuhei, Neo Masashi
Department of Orthopedic Surgery, Katsuragi Hospital, 2-33-1 Habumahi, Higashikishiwada-city, Osaka, 596-0825, Japan; Department of Orthopedic Surgery, Osaka Medical College, 2-7 Daigakumachi, Takatsuki-city, Osaka, 569-8686, Japan.
Department of Orthopedic Surgery, First Towakai Hospital, 2-17 Miyanomachi, Takatsuki-city, Osaka, 569-0081, Japan.
J Orthop Sci. 2019 Sep;24(5):867-872. doi: 10.1016/j.jos.2019.02.001. Epub 2019 Feb 21.
Causes of spontaneous osteonecrosis of the knee (SONK) have not been clearly elucidated. This study investigated the relationship between medial meniscal extrusion and SONK.
We reviewed 108 SONK knees and determined their Aglietti stage. Meniscal extrusion is defined when it extends beyond the medial margin of tibial plateau and osteophytes are excluded for determining the margin. Both absolute extrusion (AE) and relative percentage of extrusion (RPE) were measured, and meniscal tear patterns were evaluated in the early stages of SONK (I and II).
All knees had meniscal extrusion. Stage I was detected in 39 knees; II, in 23; III, in 16; IV, in 18; and V, in 12. The mean AE and RPE were 4.2 mm and 42% in stage I, 5.0 mm and 52% in stage II, 6.8 mm and 71% in stage III, 7.0 mm and 69% in stage IV, and 7.8 mm and 80% in stage V, respectively. The knees in the early stages showed less AE and RPE than those in late stages IV (p < 0.05) and V (p < 0.01). Additionally, the level of AE (ρ = 0.63, p < 0.0001) and RPE (ρ = 0.58, p < 0.0001) correlated with the SONK stage. Of knees with early-stage SONK, 12 knees had no tear, 26 had horizontal tears, 1 had longitudinal tear, 6 had degenerative tears, 2 had radial tears, 1 had complex tear, and 14 had root tears. Neither AE nor RPE differed significantly among tear patterns.
Meniscal extrusion was recognized even in early stages, with a significant correlation between the SONK stage and extrusion. Although the most frequent tear pattern in early-stage SONK was horizontal tear, 12 knees had meniscal extrusion with no tears. Therefore, meniscal extrusion, which indicates meniscal dysfunction, may be a cause of SONK and be related with the developmental stage of SONK.
膝关节自发性骨坏死（SONK）的病因尚未完全阐明。本研究调查了内侧半月板挤出与SONK之间的关系。
我们回顾了108例SONK膝关节病例，并确定其阿涅利蒂分期。当半月板超出胫骨平台内侧边缘时定义为半月板挤出，确定边缘时排除骨赘。测量绝对挤出量（AE）和相对挤出百分比（RPE），并在SONK早期阶段（I期和II期）评估半月板撕裂模式。
所有膝关节均存在半月板挤出。I期39例；II期23例；III期16例；IV期18例；V期12例。I期的平均AE和RPE分别为4.2毫米和42%，II期为5.0毫米和52%，III期为6.8毫米和71%，IV期为7.0毫米和69%，V期为7.8毫米和80%。早期阶段的膝关节AE和RPE低于IV期（p<0.05）和V期（p<0.01）晚期阶段的膝关节。此外，AE水平（ρ=0.63，p<0.0001）和RPE水平（ρ=0.58，p<0.0001）与SONK分期相关。在早期SONK膝关节中，12例无撕裂，26例为水平撕裂，1例为纵向撕裂，6例为退行性撕裂，2例为放射状撕裂,1例为复杂撕裂，14例为根部撕裂。撕裂模式之间的AE和RPE均无显著差异。
即使在早期阶段也可发现半月板挤出，SONK分期与挤出之间存在显著相关性。虽然早期SONK中最常见的撕裂模式是水平撕裂，但有12例膝关节存在半月板挤出且无撕裂。因此，表明半月板功能障碍的半月板挤出可能是SONK的一个病因，并且与SONK的发展阶段有关。
