Riann Palmieri-Smith - US grants

[unreadable] DESCRIPTION (provided by applicant): The rationale for this application is to allow Dr. Riann Palmieri-Smith to receive both the didactic training and practical research experience necessary for her evolution into an independent clinical research scientist. This award will provide her with an opportunity to complete coursework in the areas of biomechanics and clinical research design. Dr. Palmieri-Smith will conduct clinical research, under the direction of Drs. Ashton-Miller, Sowers, and Wojtys examining the impact of quadriceps inhibition on knee mechanics and will also examine the feasibility of introducing neuromuscular electrical stimulation (NMES) as an adjunct to ACL rehabilitation. Building on the experience gathered during the period of this award, Dr. Palmieri-Smith will use the information she obtains from mechanistic, laboratory-based studies to develop and test clinical interventions that can improve the neuromuscular and functional recovery of persons following traumatic knee joint injury and those with osteoarthritis. The proposed research will determine the magnitude of quadriceps inhibition necessary to result in biomechanical, functional, and neuromuscular adaptations, and the feasibility of introducing NMES, an intervention capable of restoring quadriceps activation, in rehabilitation post-ACL reconstruction to restore normal mechanics. The burst superimposition technique will be utilized in subsets of ACL reconstructed patients to estimate quadriceps inhibition prior to and following ACL reconstruction and prior to and following NMES. Mechanics will be examined during a onelegged forward hop. RELEVANCE: Quadriceps inhibition is present following ACL injury and reconstruction and often persists for years following repair and its consequences remain elusive. Our work will allow for a better understanding of how muscle dysfunction impacts joint protective mechanisms. Introducing NMES as an adjunct to ACL rehabilitation may promote sustained improvements in quadriceps activation thereby restoring lower extremity mechanics and potentially reducing the incidence of post-traumatic osteoarthritis. This knowledge will aid clinicians in designing appropriate rehabilitation protocols and return to play guidelines that will prevent future injury and joint degeneration. [unreadable] [unreadable] [unreadable] [unreadable]

Abstract Quadriceps weakness develops rapidly after anterior cruciate ligament (ACL) injury and surgery. Despite aggressive rehabilitation, most people have noteworthy quadriceps weakness when they return to activity. This persistent quadriceps weakness has been associated with altered gait patterns, reduced functional performance, and poor long-term knee health-related quality of life. Emerging evidence also indicates that quadriceps weakness plays a crucial role in the development of post-traumatic osteoarthritis ? a negative outcome that is inevitable in almost 50% of this population. Thus, there is a pressing need for new, clinically- feasible intervention strategies to improve quadriceps function after ACL injury and surgery. We hypothesize that a lack of task-specific training elements in current rehabilitation approaches is the underlying reason for the inability to optimally address persistent asymmetry in knee strength and gait after ACL surgery. Accordingly, the current proposal aims to improve quadriceps function in individuals with anterior cruciate ligament (ACL) reconstruction via a novel paradigm, termed as functional resistance training. Progressive functional resistance training will be performed during walking for 8-weeks using a low-cost wearable robotic brace that is capable of providing scalable resistive torques. Various knee-related biomechanical, neuromuscular, and clinical outcomes will be evaluated both before and after the intervention, and will be compared with a dose-matched control group. The effects of progressive functional resistance training during gait on cortical and spinal reflex excitability will also be evaluated to understand the mechanistic underpinnings of improvements mediated by the intervention. The results of the proposed studies will establish the feasibility of functional resistance training to normalize biomechanical and neuromuscular profiles in individuals with ACL reconstruction. More importantly, the proposed application, if successful, may serve as a foundation for a novel paradigm to target quadriceps dysfunction in individuals with a wide range of knee injuries.

ABSTRACT Restoring quadriceps muscle strength following anterior cruciate ligament reconstruction (ACLR) may help prevent the post-traumatic knee osteoarthritis that affects over 50% of knees 10-20 years after surgical reconstruction. However, a fundamental gap exists in our understanding of how to maximize muscle strength following ACLR, as current rehabilitation fails to restore symmetrical quadriceps strength. Our pilot work shows that when patients return to activity, quadriceps strength is ~70% of the uninjured side, which is far below the recommended 90%. Further, our data suggest that embedding high-intensity neuromuscular electrical stimulation (NMES) and eccentric exercise into standard of care ACL rehabilitation leads to higher quadriceps strength when compared with standard of care alone. However, the true efficacy of these interventions is unknown, as we currently lack controlled trials with adequate sample sizes. The absence of this information serves as the driving force and focus of the proposed trial. Therefore, we propose a double- blind randomized controlled trial where ACLR patients will be randomized to 1 of 4 arms. Study arms will include: 1) 8 weeks of NMES+8 weeks of eccentric exercise; 2) 8 weeks of NMES placebo+8 weeks of eccentric exercise; 3) 8 weeks of NMES+8 weeks of eccentric placebo; and 4) 8 weeks of NMES placebo+8 weeks of eccentric placebo. All study arms will receive standard of care ACL rehabilitation in addition to the study interventions. We hypothesize that subjects receiving NMES+eccentric exercise (Arm 1) will realize greater improvements in strength and biomechanical function at 6 months following ACLR than patients in the other 3 study arms. Further, we anticipate that patients in the NMES+eccentric exercise arm (Arm 1) will best eliminate negative changes in cartilage health at 18 months following ACLR. This study is innovative, because it employs interventions that directly target the primary mechanisms that result in strength loss following ACLR and will also evaluate whether improving muscle strength can minimize early changes in cartilage health, which may be indicative of future osteoarthritis. The proposed research is significant because it will identify evidence-based treatment approaches that can successfully counteract the muscle weakness which plagues ACLR patients for years after injury and contributes to the onset of post-traumatic osteoarthritis.