Tibial slope and medial meniscectomy significantly influence short-term knee laxity following ACL reconstruction

Abstract

Purpose: To determine demographic, anatomic, and surgical factors associated with static and dynamic Anterior Tibial Translation (ATT) following ACL reconstruction. The hypothesis was that both static and dynamic ATT would be greater in knees with high tibial slope or that required meniscectomy.

Methods: The authors prospectively enrolled 280 consecutive patients that had primary ACL reconstruction using hamstring autografts at one center for which preoperative tear type, meniscal tears, and medial tibial slope were documented. A total of 137 were excluded due to concomitant extra-articular tenodesis or surgical antecedents on either knee, and 18 were lost to follow-up, leaving 125 that were evaluated at a minimum of 6 months including: static ATT on monopodal weight-bearing radiographs, and dynamic ATT on differential stress radiographs using the Telos™ device.

Results: Both postoperative static and dynamic ATT were strongly associated with preoperative static and dynamic ATT (respectively, β = 0.068 and β = 0.50, p < 0.001). Multivariable regression confirmed that postoperative static ATT increased with tibial slope (β = 0.24; CI 0.01-0.47; p = 0.042) and in knees that had partial medial meniscectomy (β = 2.05; CI 0.25-3.84; p = 0.025), while dynamic ATT decreased with age (β = - 0.11; CI - 0.16 to - 0.05; p < 0.001), and increased with tibial slope (β = 0.27; CI 0.04-0.49; p = 0.019) and in knees that had partial medial meniscectomy (β = 2.20; CI 0.35-4.05; p = 0.019).

Conclusion: Both static and dynamic ATT following ACL reconstruction increased with tibial slope and in knees that had partial medial meniscectomy. These findings could help surgeons tailor their techniques and 'à la carte' rehabilitation protocols, by preserving the menisci and sometimes delaying full weight-bearing and return to sport in patients at risk, and hence improve outcomes and prevent graft failures.

Study design: Cohort study.

Level of evidence: V.

Keywords: ACL reconstruction; Anterior cruciate ligament; Knee laxity; Meniscal tears; Tibial slope.