Atypical Lower Limb Mechanics During Weight Acceptance of Stair Descent at Different Time Frames After Anterior Cruciate Ligament Reconstruction

Abstract

Background: An anterior cruciate ligament (ACL) rupture may result in poor sensorimotor knee control and, consequentially, adapted movement strategies to help maintain knee stability. Whether patients display atypical lower limb mechanics during weight acceptance of stair descent at different time frames after ACL reconstruction (ACLR) is unknown. Purpose: To compare the presence of atypical lower limb mechanics during the weight acceptance phase of stair descent among athletes at early, middle, and late time frames after unilateral ACLR. Study Design: Controlled laboratory study. Methods: A total of 49 athletes with ACLR were classified into 3 groups according to time after ACLR—early (<6 months; n = 17), middle (6-18 months; n = 16), and late (>18 months; n = 16)—and compared with asymptomatic athletes (control; n = 18). Sagittal plane hip, knee, and ankle angles; angular velocities; moments; and powers were compared between the ACLR groups’ injured and noninjured legs and the control group as well as between legs within groups using functional data analysis methods. Results: All 3 ACLR groups showed greater knee flexion angles and moments than the control group for injured and noninjured legs. For the other outcomes, the early group had, compared with the control group, less hip power absorption, more knee power absorption, lower ankle plantarflexion angle, lower ankle dorsiflexion moment, and less ankle power absorption for the injured leg and more knee power absorption and higher vertical ground reaction force for the noninjured leg. In addition, the late group showed differences from the control group for the injured leg revealing more knee power absorption and lower ankle plantarflexion angle. Only the early group took a longer time than the control group to complete weight acceptance and demonstrated asymmetry for multiple outcomes. Conclusion: Athletes with different time frames after ACLR revealed atypically large knee angles and moments during weight acceptance of stair descent for both the injured and the noninjured legs. These findings may express a chronically adapted strategy to increase knee control. In contrast, atypical hip and ankle mechanics seem restricted to an early time frame after ACLR. Clinical Relevance: Rehabilitation after ACLR should include early training in controlling weight acceptance. Including a control group is essential when evaluating movement patterns after ACLR because both legs may be affected.

Stepping it up: A Longitudinal Assessment of Stair Negotiation Among ACL Reconstruction Patients Outside the Laboratory

“…The mean ankle dorsiflexion angle of the injured leg was lower than the angle of the contralateral ankle at 8-38% and less plantarflexed at 67-83%, as seen by two supra-threshold clusters exceeding the critical threshold of t [1,17]=3.46, p<.005. During stair descent, the injured ankle was less dorsiflexed at 18-41% of the cycle, as seen by a single supra-threshold cluster exceeding the critical threshold of t [1,17]=3.42, p<.001.…”

“…As seen in Figure 3, the mean knee flexion angle of the injured leg was lower than the contralateral knee at 10-32% of the cycle, as seen by a single supra-threshold cluster exceeding the critical threshold of t [1,17]=3.25, p=.001. Similarly, during stair descent, the injured knee was less flexed than the contralateral knee at 20-29% of the cycle, as seen by a single supra-threshold cluster exceeding the critical threshold of t [1,17]=3.36, p=.017.…”

Lower extremity joint contact force symmetry during walking and running, 2–7 years post‐ACL reconstruction

“…For instance, reduced peak ankle dorsiflexion moment in the involved limb after ACLR 49,50 as well as reduced ankle plantarflexion angle, dorsiflexion angular velocity and power absorption were observed in the short term after ACLR. However, these differences were not significant beyond 18 months after ACLR.…”

“…However, peak ankle joint plantarflexor moment (Table 5) for ACLR participants were highly symmetrical which is consistent with the available literature, and supports the premise that, unlike knee JCF, ankle JCF during gait tasks seem to become symmetrical over time. For instance, reduced peak ankle dorsiflexion moment in the involved limb after ACLR 49,50 as well as reduced ankle plantarflexion angle, dorsiflexion angular velocity and power absorption were observed in the short term after ACLR. However, these differences were not significant beyond 18 months after ACLR 17 .…”

Mechanical energy flow analysis in athletes with and without anterior cruciate ligament reconstruction during single-leg drop landing

“…There are several factors thought to contribute to secondary ACL injuries 7 , 8 . The most significant biomechanical factors are kinematic, neuromuscular and kinetic.…”