Spontaneous osteonccrosis of the knee was first described in 1986 by Ahlback et al, as a painful radiolucent lesion associated with a focally active bone scan involving the medial femoral condyle, but without any of such well known predisposing
factors
as oral steroids, lupus erythematosus, hyperlipidemia, alcohol, or Caisson´s disease.
The etiology of the lesion is still unknown and this entity is believed to be an important out underestimated cause of osteoarthritis of the knee, the clinical course and the prognosis of the disease depend on the radiographic size, the area, and
the
stage of the lesion. Bone scan allows and early diagnosis, and MRI is useful in the evaluation of separated osteonecrosis of the knee and the determination of the prognosis.
Prognosis is unfavorable if condyle. Arthroscopy not only allows an effective method of evaluating the articular lesion, but also provides an effective treatment. When varus deformity deformity is present, the arthroscopic treatment can be
associated
with a high tibial osteotomy. During the period of 4 years from February, 1989 to July, 1993, spontaneous osteonecrosis was diagnosed in 15 knees in 13 patients. Of the 6 kn4ees followed up after conservative treatment, 83% were satisfactory. Of
the 6
knees treated by arthroscopic debridement, 83% were satisfactory, and of the k3 knees treated by osteotomy, all were satisfactory.
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