Non-operative treatment of ACL injury is associated with opposing subjective and objective outcomes over 20 years of follow-up

Purpose The aim of this study was the evaluation of long-term clinical and radiological outcomes of non-operative treatment of anterior cruciate ligament (ACL) deficiency. The hypothesis was that conservative treatment would be associated with a deterioration of subjective and objective measures of joint health and disability over time. Methods From an initial sample of 41 patients conservatively treated for ACL rupture, 10 received secondary ACL reconstruction, 1 was excluded due to contralateral ACL injury, and 1 patient required total knee replacement and a high tibial osteotomy. Seven further patients were lost to follow-up. The remaining 21 patients (15 male, 6 female, mean age 53.1 ± 9.2 years at the last follow-up) were evaluated by the same two examiners 5–7, 10–13 and 20–22 years after the injury. The evaluation was based on objective and subjective scores, instrumented testing, radiographic examination and assessment of sports activity. Results While subjective patient satisfaction improved over time, objective scores stayed constant or deteriorated (radiologic evaluation). Instrumented knee laxity testing showed an initial tendency to increasing instability, followed by a decrease in anterior tibial translation in the second half of the observation period. Physical activity levels, particularly in high-risk sports, decreased significantly ( p < 0.05) compared to preinjury levels. All patients developed significant arthritic degenerative changes over time compared to the uninjured contralateral knee. No correlation to activities in high- or low-risk pivoting sports was found. Conclusions Patient satisfaction with conservative treatment of ACL injuries is good in spite of objective measures indicating increasing degenerative changes. Level of evidence IV.