Effect of Early Residual Laxity After Anterior Cruciate Ligament Reconstruction on Long-term Laxity, Graft Failure, Return to Sports, and Subjective Outcome at 25 Years

Background: In spite of supposedly successful surgery, slight residual knee laxity may be found at follow-up evaluations after anterior cruciate ligament reconstruction (ACLR), and its clinical effect is undetermined.

Purpose: To investigate whether a 3- to 5-mm increase in anterior translation 6 months after ACLR affects the risk of graft failure, rate of return to sports, and long-term outcome.

Study design: Cohort study; Level of evidence, 2.

Methods: From a cohort of 234 soccer, team handball, and basketball players undergoing ACLR using bone-patellar tendon-bone graft, 151 athletes were included who attended 6-month follow-up that included KT-1000 arthrometer measures. A tight graft was defined as <3-mm side-to-side difference between knees (n = 129), a slightly loose graft as 3 to 5 mm (n = 20), and a loose graft as >5 mm (n = 2). Graft failure was defined as ACL revision surgery, >5-mm side-to-side difference, or anterolateral rotational instability 2+ or 3+ at 2-year follow-up. Finally, a 25-year evaluation was performed, including a clinical examination and questionnaires.

Results: The rate of return to pivoting sports was 74% among athletes with tight grafts and 70% among those with slightly loose grafts. Also, return to preinjury level of sports was similar between those with slightly loose and tight grafts (40% vs 48%, respectively), but median duration of the sports career was longer among patients with tight grafts: 6 years (range, 1-25 years) vs 2 years (range, 1-15 years) (P = .01). Five slightly loose grafts (28%) and 6 tight grafts (5%) were classified as failures after 2 years (P = .002). Thirty percent (n = 6) of patients with slightly loose grafts and 6% (n = 8) with tight grafts had undergone revision (P = .004) by follow-up (25 years, range, 22-30 years). Anterior translation was still increased among the slightly loose grafts as compared with tight grafts at long-term follow-up (P < .05). In patients with tight grafts, 94% had a Lysholm score ≥84 after 24 months and 58% after 25 years, as opposed to 78% (P = .02) and 33% (P = .048), respectively, among patients with slightly loose grafts.

Conclusion: A slightly loose graft at 6 months after ACLR increased the risk of later ACL revision surgery and/or graft failure, reduced the length of the athlete's sports career, caused permanent increased anterior laxity, and led to an inferior Lysholm score.