自發性膝關節壞死－－38病例分析

Spontaneous Osteonecrosis of Knee (SONK) An Analysis of 38 Cases

「自發性膝關節壞死」是1968年Ahlbäck等首先描述的病症，常發生在60歲以上的老人。臨床上具有急性發作、局部壓痛、休息時疼痛、關節積水等特性。最常發生的部位是股骨的內髁。發病早期因放射線檢查常無特殊發現，晚期又與骨關節炎很難區別，故常被誤診。三相式骨掃描(radionuclide three phase bone scan)對早期的診斷非常重要。部份病患，早期發現後給予適當的治療，尚有痊癒的機會，故三相式骨掃描對急性膝關節內側疼痛的病人，有其特殊的意義。本院自民國72年1月至76年1月，有38例（47膝關節）自發性膝關節壞死。男女之比為21比17。男性平均年齡為66.4±6.3歲，女性平均年齡為60.1±7.1歲。所有病例皆有局部疼痛、壓痛等現象。47例被侵犯的膝關節中，36例(76.6％)，之膝關節X光，已先有骨關節炎。所有的38例病患，22例(58％)為急性發作。11例(29％)單獨侵犯股骨內髁，7例(18％)單獨侵犯內側脛骨崗，1例(3％)侵犯股骨外髁，其餘19例(50％)均侵犯二個以上的部位，包括股骨內髁或內側脛骨崗。13例患者之膝關節有關節積水，在17次關節液檢查，16次為正常或第一級炎性反應（白血球數介於200至2000/ cumm)。27例(57.4％)膝關節，X光無法診斷，均靠三相式骨掃描加以證實。除三例接受手術外，其餘均採用保守療法。

SONK was first described by Ahlbäck in 1968. Clinical manifestations include acute onset of pain, local tenderness, resting pain of involved area. The most common site of involvement is medial femoral condyle. It is frequently neglected due to negative roentgenograms in the initial stage and osteoarthritis appearance in the late stage. However, radionuclide three phase bone scan is sensitive to establish the diagnosis in early stage. From Jan. 1983 to Jan. 1987, we diagnosed 38 cases (47 knees) with SONK in our hospital, 21 were males and 17 were females; the mean age (years) was 66.4 ± 6.3 in male and 60.2 ± 7.1 in female. All patients had localized pain and tenderness over knee. Previous X ray of 36 knees (76.6%) showed osteoarthritis. It was abrupt in onset in 22 (58%) of our 38 cases with SONK it was found 11 (29%) cases had necrosis on medial femoral condyle, 7 (18%) cases on medial tibial platean, and only 1 (3%) case on lateral femoral condyle. The remainder (50%) of our cases had more than 2 sites with necrosis at the same time. Twenty seven knees (57.4%) of SONK diagnosed by three phase bone scan could not be diagnosed by roentgenograms. The majority of our cases were treated conservatively and responded well except for 3 cases who eventually reecived the surgical operation.