Long-term followup of the untreated isolated posterior cruciate ligament-deficient knee.

We evaluated 38 subjects with isolated posterior cruciate ligament-deficient knees at a mean of 13.4 years (range, 5 to 38) after injury to study the occurrence of symptoms, disabilities, and articular degeneration. Each subject completed a standardized questionnaire, physical examination, and had radiographs taken of both knees. Eight (21%) patients had surgeries for meniscal injuries after their posterior cruciate ligament injuries. The mean questionnaire score for function (50-point maximum) was 34.4 +/- 6.5 (SD) for the patients who did have meniscal surgeries versus 40.0 +/- 8.7 for the 30 patients who did not (P = 0.05). Among the 30 patients with isolated posterior cruciate ligament-deficient knees with normal menisci, 24 (81%) had at least occasional pain and 17 (56%) had at least occasional swelling. As time from injury increased, increased articular degeneration on radiographs was seen (P = 0.037). Our study suggests that the prognosis for the isolated posterior cruciate ligament-deficient knee varies. Some patients experience significant symptoms and articular deterioration, while others are essentially asymptomatic and maintain their usual knee function.