Individuals With an Anterior Cruciate Ligament–Reconstructed Knee Display Atypical Whole Body Movement Strategies but Normal Knee Robustness During Side-Hop Landings: A Finite Helical Axis Analysis

Abstract

Background: Atypical knee joint biomechanics after anterior cruciate ligament reconstruction (ACLR) are common. It is, however, unclear whether knee robustness (ability to tolerate perturbation and maintain joint configuration) and whole body movement strategies are compromised after ACLR. Purpose: To investigate landing control after ACLR with regard to dynamic knee robustness and whole body movement strategies during sports-mimicking side hops, and to evaluate functional performance of hop tests and knee strength. Study Design: Controlled laboratory study. Methods: An 8-camera motion capture system and 2 synchronized force plates were used to calculate joint angles and moments during standardized rebound side-hop landings performed by 32 individuals with an ACL-reconstructed knee (ACLR group; median, 16.0 months after reconstruction with hamstring tendon graft [interquartile range, 35.2 months]) and 32 matched asymptomatic controls (CTRL). Dynamic knee robustness was quantified using a finite helical axis approach, providing discrete values quantifying divergence of knee joint movements from flexion-extension (higher relative frontal and/or transverse plane motion equaled lower robustness) during momentary helical rotation intervals of 10°. Multivariate analyses of movement strategies included trunk, hip, and knee angles at initial contact and during landing and hip and knee peak moments during landing, comparing ACLR and CTRL, as well as legs within groups. Results: Knee robustness was lower for the first 10° motion interval after initial contact and then successively stabilized for both groups and legs. When landing with the injured leg, the ACLR group, as compared with the contralateral leg and/or CTRL, demonstrated significantly greater flexion of the trunk, hip, and knee; greater hip flexion moment; less knee flexion moment; and smaller angle but greater moment of knee internal rotation. The ACLR group also had lower but acceptable hop and strength performances (ratios to noninjured leg >90%) except for knee flexion strength (12% deficit). Conclusion: Knee robustness was not affected by ACLR during side-hop landings, but alterations in movement strategies were seen for the trunk, hip, and knee, as well as long-term deficits in knee flexion strength. Clinical Relevance: Knee robustness is lowest immediately after landing for both the ACLR group and the CTRL and should be targeted in training to reduce knee injury risk. Assessment of movement strategies during side-hop landings after ACLR should consider a whole body approach.

Trunk Biomechanics in Individuals with Knee Disorders: A Systematic Review with Evidence Gap Map and Meta-analysis

“…5 A]). Moderate-certainty evidence with small effect from 13 studies (933 participants) [ 34 , 104 , 106 , 108 – 110 , 112 – 114 , 117 – 119 , 122 ] showed greater peak/RoM trunk flexion in individuals with ACLR compared to controls during landing tasks (SMD = 0.48; 95% CI = 0.21–0.75; Z = 3.48, P = 0.005 [Fig. 5 A]).…”

“…5 C]). Moderate-certainty evidence from 6 studies (568 participants) [ 34 , 104 , 106 , 113 , 116 , 119 ] showed no differences between groups for ipsilateral trunk lean (peak/RoM) during landing tasks (SMD = 0.23; 95% CI = − 0.05 to 0.51; Z = 1.58, P = 0.11 [Fig. 5 C]).…”

“…Moderate-certainty evidence demonstrated greater trunk flexion in individuals with ACLR during landing tasks [ 104 , 106 , 108 – 110 , 112 – 114 , 122 ], likely to reduce quadriceps demand and knee pain. A subgroup of athletes at the time of return-to-sport after ACLR with low-quadriceps symmetry between limbs (i.e., < 85% of isometric strength) presented greater trunk flexion during landing compared to controls [ 141 ].…”

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

“…A 15-segment 6 degrees of freedom model was constructed in Visual3D (Version 5.02.30; C-Motion) from 56 passive spherical markers attached with double-coated adhesive tape on the skin at anatomic landmarks, as previously described in detail. 33 Participants wore rigid clusters with 4 markers on each thigh to improve construct validity by reducing the effects of soft tissue artifacts. 12 The marker data were tracked with Qualisys Track Manager software (Version 2.11) and filtered at 15 Hz with a critically dampened digital filter before being used to calculate the outcome variables.…”

Fear of Reinjury Following Anterior Cruciate Ligament Reconstruction Is Manifested in Muscle Activation Patterns of Single-Leg Side-Hop Landings

“…The ACL-reconstructed legs in HIGH-FEAR and LOW-FEAR were compared to the nondominant legs among CTRL (non-preferred leg when kicking a ball) for all between-group analyses, in accordance with previous biomechanical studies from our research group. [39][40][41][42] Mean values were calculated and used for each outcome variable from the 5 successful trials.…”