Thigh muscle atrophy and postoperative osteoarthrosis after knee ligament tears.

The aim of the study was to clarify if atrophy of the thigh muscles was related to the radiological and clinical long-term healing results of primary knee ligament surgery. At the Tampere University Central Hospital a radiological and clinical reexamination was performed in 61 patients on an average 40 months after primary operation of acute knee ligament injury. The study group consisted of 26 patients having clear quadriceps muscle atrophy in the injured knee at the follow-up. Thirty-four patients with equal circumference of the thighs, served as controls. One patient was excluded. The groups did not differ significantly from each other in respect to age, sex, physical activity, type of ligament injury, meniscectomy, and follow-up time. In radiological evaluation the previously developed knee scoring scale was used taking into account only changes caused by the studied injury. The mean score of the study group was 93.7 +/- 6.2 (range 73-100) and the controls 96.2 +/- 4.0 (87-100); p less than 0.05. In both the most common changes of post-traumatic osteoarthrosis were osteophytes, ligament calcification and joint space narrowing. In clinical examination the patients of the study group were placed significantly more often in the groups of fair or poor healing in subjective, objective, overall (in each p less than 0.001) and functional (p less than 0.05) evaluation. According to this study, it seems that thigh muscle atrophy plays an important role as a poor prognostic factor of knee ligament injuries being thus a good target for efforts to stop the continuous deterioration of the injured knee. Obviously the post-traumatic osteoarthrotic process is a vicious circle: thigh atrophy increases dynamic knee instability, which in turn not only starts or accelerates the arthrotic process but also increases--by discomfort and disuse of the knee--the atrophy itself.