Joint contributions to sagittal plane total support moment in patients with knee osteoarthritis after anterior cruciate ligament reconstruction.

BACKGROUND: Patients with anterior cruciate ligament reconstruction (ACLR) demonstrate lower knee loading. This study aimed to determine whether sagittal plane TSM and joint contributions to total support moment (TSM) in the surgical limb are different between athletes who did and did not show radiological features of knee OA at 2 years after ACLR during triple hops (TH), single hop (TH), single-legged vertical jump (VJ), and walking. METHODS: Forty-one athletes with 2 years of unilateral ACLR surgery participated in this cross-sectional study. Athletes completed motion analysis testing of single-legged TH, SH, VJ, and walking tasks. Sagittal plane TSM and individual joint (ankle, knee, and hip) contributions to TSM were computed at peak knee flexion angle (TSM-PKF). Posterior-anterior radiographs were completed in standing and 30° knee flexion. Kellgren-Lawrence (KL) system was used to identify radiological features of knee OA in the medial compartment of the reconstructed knee (OA-group: KL ≥2; Non-OA group: KL<2). RESULTS: There was a significant group-by-joint-by-task interaction for joint contributions to TSM-PKF (p = 0.012), with the OA-group (n = 13) had lower knee and higher hip contributions compared to the non-OA group during TH, SH, and VJ (p ≤ 0.049). There was a significant joint-by-group interaction for the joint contributions to TSM-PKF (p = 0.004), with the OA-group having lower knee (p = 0.003) and higher hip (p = 0.001) contributions compared to the Non-OA group. SIGNIFICANCE: The OA-group exhibited lower knee and higher hip contributions to the sagittal plane TSM compared to the Non-OA group during the landing phase of single-limb high-demand activities. The OA-group exhibited decreased knee loading and compensated by shifting the mechanical load to the hip joint within the reconstructed knee. Decreased knee loading in the OA-group may have affected the required mechanical loading to maintain knee metabolism and integrity.

Patient-Reported Measures Associated with the Return to Pre-Injury Levels of Sport 2 Years after Anterior Cruciate Ligament Reconstruction.

The International Knee Documentation Committee Subjective Knee Form (IKDC2000) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) are knee-specific measures. However, their association with a return to sports after anterior cruciate ligament reconstruction (ACLR) is unknown. This study aimed to investigate the association between the IKDC2000 and the KOOS subscales and the return to the same pre-injury level of sport two years after ACLR. Forty athletes that were two years post-ACLR participated in this study. Athletes provided demographic information, filled out the IKDC2000 and KOOS subscales, and indicated whether they returned to any sport and whether they returned to the same pre-injury level (same duration, intensity, and frequency). In this study, 29 (72.5%) athletes returned to play any sport and eight (20%) returned to the same pre-injury level. The IKDC2000 (r: 0.306, p = 0.041) and KOOS quality of life (KOOS-QOL) (r: 0.294, p = 0.046) significantly correlated with the return to any sport, but it was age (r: -0.364, p = 0.021), BMI (r: -0.342, p = 0.031), IKDC2000 (r: 0.447, p = 0.002), KOOS-pain (r: 0.317, p = 0.046), KOOS sport and recreation function (KOOS-sport/rec)(r: 0.371, p = 0.018), and KOOS QOL (r: 0.580, p > 0.001) that significantly correlated with a return to the same pre-injury level. High KOOS-QOL and IKDC2000 scores were associated with returning to any sport, and high KOOS-pain, KOOS-sport/rec, KOOS-QOL, and IKDC2000 scores were all associated with returning to the same pre-injury level of sport.

Hip Abductor and External Rotator Strengths Correlate With Hop Symmetry in Men Athletes 2 Years After Anterior Cruciate Ligament Reconstruction.

CONTEXT: Hip muscle strength and hop performance limb symmetries after anterior cruciate ligament reconstruction (ACLR) are not well studied. This study aimed to determine the differences in hip abductors' (ABD) and external rotators' (ER) muscle strength measures between limbs, and the relationship between hip ABD and ER muscle strengths and hop performance limb symmetry indices (LSIs) 2 years after ACLR. DESIGN: Cross-sectional study. METHODS: Forty (level I/II) men athletes 2 years after unilateral ACLR completed 4 single-legged hop tests and involved hip ABD and ER strength testing (maximum voluntary isometric contraction [MVIC]; isokinetic peak torque [PKTQ] at 60°, 180°, and 300°/s; and isotonic peak velocity at 75% of their MVICs). Muscle strength measures were normalized to body mass, and hop performances were reported as LSIs. Paired t test was used to determine strength differences between limbs, and the Pearson correlation coefficient was used to assess the relationship between involved hip muscle strength measures and hop performance LSIs. RESULTS: Hip ER-MVIC (involved: 60.26 [12.01], uninvolved: 63.68 [13.17] N·m/kg) and ER eccentric PKTQ at 60°/s (involved: 32.59 [9.28]; uninvolved: 35.73 [10.50] N·m/kg) were significantly different between limbs (P ≤ .018). Single-hop LSI correlated with hip ER-PKTQ at 180°/s (r = .354) and 300°/s (r = .324, P ≤ .041), while triple-hop LSI correlated with hip ER-MVIC (r = .320), concentric ER-PKTQ at 180°/s (r = .355), eccentric ER-PKTQ at 60°/s (r = .314), and hip ABD-PKTQ at 60°/s (r = .364) and 300°/s (r = .336, P ≤ .049). CONCLUSIONS: Men athletes demonstrated symmetrical hop performance and hip muscle strengths, except for ER hip's MVIC and isokinetic eccentric peak torque at 60°/s 2 years after ACLR. Hop performance LSIs had a few, yet positive moderate relationships with involved hip ABDs and ER strength measures. This may indicate that hip ABD and ER muscle strength measures contribute to athletes' hop performances 2 years after ACLR. Post-ACLR rehabilitation programs might incorporate hip muscle strengthening training to improve athletes' functional performances.