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Objective. Restoring quadriceps muscle strength following anterior cruciate ligament reconstruction (ACLR) may prevent the posttraumatic osteoarthritis that affects over 50% of knees with ACLR. However, a fundamental gap exists in our understanding of how to maximize muscle strength through rehabilitation. Neurological deficits and muscle atrophy are 2 of the leading mechanisms of muscle weakness after ACLR. High-intensity neuromuscular electrical stimulation (NMES) and eccentric exercise (ECC) have been shown to independently target these mechanisms. If delivered in succession, NMES and then ECC may be able to significantly improve strength recovery. The objectives of this study were to evaluate the ability of NMES combined with ECC to restore quadriceps strength and biomechanical symmetry and maintain cartilage health at 9 and 18 months after ACLR. Methods. This study is a randomized, double-blind, placebo-controlled, single-center clinical trial conducted at the University of Michigan. A total of 112 participants between the ages of 14 and 45 years and with an anterior cruciate ligament rupture will be included. Participants will be randomly assigned 1:1 to NMES combined with ECC or NMES placebo combined with ECC placebo. NMES or NMES placebo will be delivered 2 times per week for 8 weeks beginning 10 to 14 days postoperatively and will be directly followed by 8 weeks of ECC or ECC placebo delivered 2 times per week. The co-primary endpoints are change from baseline to 9 months and change from baseline to 18 months after ACLR in isokinetic quadriceps strength symmetry. Secondary outcome measures include isometric quadriceps strength, quadriceps activation, quadriceps muscle morphology (cross-sectional area), knee biomechanics (sagittal plane knee angles and moments), indexes of patient-reported function, and cartilage health (T1[rho] and T2 relaxation time mapping on magnetic resonance imaging). Impact. The findings from this study might identify an intervention capable of targeting the lingering quadriceps weakness after ACLR and in turn prevent deterioration in cartilage health after ACLR, thereby potentially improving function in this patient population., Anterior cruciate ligament (ACL) reconstruction (ACLR) leads to significant reductions in quadriceps strength, (1-3) and this decreased strength is related to a decreased quality of life, (4) higher risk of [...]

Background. Neuromuscular electrical stimulation (NMES) has demonstrated efficacy in improving quadriceps muscle strength (force-generating capacity) and activation following knee replacement and ligamentous reconstruction. Yet, data are lacking to establish the efficacy of NMES in people with evidence of early radiographic osteoarthritis. Objective. The purpose of this study was to determine whether NMES is capable of improving quadriceps muscle strength and activation in women with mild and moderate knee osteoarthritis. Design. This study was a randomized controlled trial. Methods. Thirty women with radiographic evidence of mild or moderate knee osteoarthritis were randomly assigned to receive either no treatment (standard of care) or NMES treatments 3 times per week for 4 weeks. The effects of NMES on quadriceps muscle strength and activation were evaluated upon study enrollment, as well as at 5 and 16 weeks after study enrollment, which represent 1 and 12 weeks after cessation of NMES among the treated participants. The Western Ontario and McMaster Universities Osteoarthritis Index and a 40-foot (12.19-m) walk test were used at each testing session. Results. Improvements in quadriceps muscle strength or activation were not realized for the women in the intervention group. Quadriceps muscle strength and activation were similar across testing sessions for both groups. Limitations. Women were enrolled based on radiographic evidence of osteoarthritis, not symptomatic osteoarthritis, which could have contributed to our null finding. A type II statistical error may have been committed despite an apriori power calculation. The assessor and the patients were not blinded to group assignment, which may have introduced bias into the study. Conclusions. Four weeks of NMES delivered to women with mild and moderate osteoarthritis and mild strength deficits was insufficient to induce gains in quadriceps muscle strength or activation. Future research is needed to examine the dose-response relationship for NMES in people with early radiographic evidence of osteoarthritis., Tibiofemoral osteoarthritis (OA) is the most common cause of chronic disability in the United States (1) and is the most frequent indication for total knee arthroplasty. (2) No cure exists [...]