Increased Risk of Osteoarthritis After Anterior Cruciate Ligament Reconstruction: A 14-Year Follow-up Study of a Randomized Controlled Trial
Barenius B, Ponzer S, Shalabi A, Bujak R, Norlen L, & Eriksson K. Am J Sports Med. 2014 Published Online First March 18, 2014: doi: 10.1177/0363546514526139
Take Home Message: Knees with a history of an anterior cruciate ligament injury are more likely to have osteoarthritis compared with a healthy contralateral knee but graft selection has no effect on long-term outcomes, such as osteoarthritis or knee functional outcomes.
An individual with a history of an acute knee injury, including anterior cruciate ligament (ACL) injury, is three to 6 six times more likely to have knee osteoarthritis (OA) than someone without a history of injury. Unfortunately, we lack a consensus on whether ACL reconstruction timing and graft selection affects the risk for knee OA. Therefore, the authors completed an extended follow up of a randomized clinical trial that compared quadrupled semitendinosus tendon and bone-patellar tendon-bone grafts. They aimed to determine if graft selection influenced the prevalence of OA 14 years after surgery. The authors assessed 135 (82%) participants from the original trial. Three radiologists assessed the presence of OA in both knees with weight-bearing radiographs and knee function was assessed via the Knee Injury and Osteoarthritis Outcome Score (KOOS). Roughly 50-70% of knees with an ACL reconstruction had radiographic OA compared with 10-25% of healthy contralateral knees. The authors found no difference in the prevalence of OA between the two graft choices. Concomitant meniscectomy at the time of ACL reconstruction increased the odds of having OA compared with individuals who had a meniscal repair or no meniscal injury. The authors also observed that time between injury and reconstruction did not influence the chances of presenting with OA. As expected, KOOS scores were lower among patients that had radiographic evidence of OA (especially in the medial compartment) in comparison with those that did not have any evidence of OA.
This study supports the notion that ACL graft selection does not affect long-term outcomes (e.g., OA prevalence, function). The high prevalence of OA among knees with an ACL reconstruction also supports previous clinical trials that found that an ACL reconstruction may not protect a knee from OA as discussed in previous posts. This is particularly concerning since the average age of participants at follow-up was only 39 to 42 years. Interestingly, this study further supports the notion that concomitant meniscal resection at the time of ACL reconstruction places an individual at a higher risk for OA. It is important to note, that the authors excluded participants who had additional surgery on the involved knee or the contralateral (healthy) knee for follow-up. It would be interesting to see if the authors found any trends among those who needed surgery on either knee within the follow up period. It would seem reasonable that the prevalence rates reported in this study may be lower than what we may see in the clinical setting because the authors excluded these patients. Overall, this study further highlights that a large number of individuals with an ACL injury may have OA early in life and that meniscal status could be a key risk factor. In a medical community focused on prevention, we need to strive to prevent not just injuries but also chronic pain conditions like OA that could affect our patients for over half their lives.
Questions for Discussion: Do you think that ACL injury is the primary culprit of OA development or is it underlying concomitant injury? Are there any other clinical findings that you see that may lead people to be more susceptible to OA development after knee injury?
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban