The natural course of untreated osteoarthritis of the knee.

Ninety-four knee joints in 71 patients had primary gonarthrosis (osteoarthritis of the knee) for periods of 10-18 years. The course of gonarthrosis was unfavorable in that a majority of the cases became worse over the years and some also developed pain at rest. The prognosis in gonarthrosis seemed worse than in coxarthrosis (osteoarthritis of the hip). The radiographic changes in the affected knee joint progressed over the years. However, in most knees the changes remained limited to the compartment first affected so that knees with initially medial involvement had exclusively medial involvement even 10-18 years later. Varus deformity was related to poor stability and to a generally poor prognosis. An early onset of symptoms was unfavorable with regard to development of pain. The majority of otherwise healthy patients became incapable of using public transportation because of knee pain on walking.