Studies of Posttraumatic Knee Osteoarthritis Following ACL Reconstruction Requires Longer Than 5-Year Minimum Follow-up

The connection between anterior cruciate ligament (ACL) injury and posttraumatic osteoarthritis is well established, with approximately half of patients developing osteoarthritis within 5 to 15 years after injury1. Some studies have shown that ACL reconstruction (ACLR) can decrease the rate of development of secondary meniscal tears, development of osteoarthritis, and progression to total knee arthroplasty, especially when performed within 1 year after injury2. There have been prior investigations into the impact of ACLR graft types, without definitive evidence of differences in progression to osteoarthritis3. The peak incidence of ACL rupture in males is in the early twenties; females have a peak in their teenage years and another in their forties, with a mean age of 33.9 years4. The study by Gkekas et al. reviewed the impact of adding lateral extra-articular tenodesis (LET) to ACLR on the rate of progression to moderate-to-severe osteoarthritis at a minimum follow-up of 5 years. They found that the addition of LET to ACLR resulted in a significant reduction in progression to moderate-to-severe osteoarthritis in the lateral compartment, with no difference in the medial compartment. Additionally, LET reduced the rate of progression to moderate-to-severe osteoarthritis in meniscectomized knees. Unfortunately, as this study was a systematic review, a comparison could not be made on the basis of the degree of meniscectomy because it was not reported in some of the studies. The results of this study suggest that LET should be considered as an adjunct to ACLR, especially in patients undergoing meniscectomy, to prevent lateral compartment progression to moderate-to-severe osteoarthritis. The work of Cheung et al.1 shows us that progression to osteoarthritis following ACLR can take 15 years or longer, so the results reported by Gkekas et al. should be interpreted with caution despite the mean follow-up of 13.1 years. This duration of follow-up would only bring the average patient with an ACL rupture to their mid-40s, and misses decades of life during which the incidence of knee osteoarthritis rapidly rises even in patients without prior ACL injury. The addition of LET certainly shows some promise for decreasing progression to moderate-to-severe osteoarthritis in the lateral compartment and, in particular, for meniscectomized knees. Nevertheless, this result must be considered in light of the relatively short time-frame of follow-up of this study compared with the remaining life expectancy of typical patients after ACLR. Further studies are needed to compare the addition of LET to ACLR to better elucidate which patients are most likely to benefit from this procedure, as well as to provide longer-term follow-up of these patients.