Purpose: To investigate and analyse outcomes of patients over the age of 40 who had undergone anterior cruciate ligament (ACL) reconstruction and to compare them to their younger counterparts. We analysed patient-reported outcomes measured using the knee injury and osteoarthritis outcome score (KOOS) as well as aetiology of injury, concomitant intra-articular injuries and time from injury to surgery.
Methods: Data were extracted from the Swedish National Knee Ligament Register during the period of 2005 through 2012. The following data were extracted and analysed: patient age, gender, activity at the time of injury, time between injury and reconstruction, concomitant intra-articular injuries, graft size used for reconstruction and KOOS measured pre-operatively as well as 1, 2 and 5 years post-operatively. The cohort was stratified into age groups of 0-19, 20-29, 30-39 and ≥ 40 years of age.
Results: Pivoting sports were dominating as the cause of ACL injury in the younger age groups (up to 39 years). Alpine skiing and other non-specified activities were the most common causes in the older age group (≥ 40 years). Pre-operative KOOS was significantly lower in older age groups (p < 0.01). Post-operative KOOS regarding all subscales was significantly better in the older age group. The improvement in KOOS was significant with increasing age (p < 0.01). Older patients exhibited the greatest improvement in KOOS for all subscales at 1, 2 and 5 years post-operative follow-ups compared with pre-operative values (p < 0.01). Older patients had more cartilage injuries pre-operatively compared with younger patients. The same trend was observed in the older group for meniscus injury with and without cartilage injuries. The diameter of the graft used for ACL reconstruction was significantly larger in the older age groups and largest in the age group ≥ 40 years (p < 0.01). Older patients waited significantly longer for surgery after the ACL injury (p < 0.01).
Conclusion: In the older age groups, patients reported lower pre-operative KOOS compared with their younger counterparts. At follow-up, KOOS was similar in all age groups. From these results, we can therefore conclude that our hypothesis confirmed that optimal surgical results can in fact be achieved even in older patients.