Patients experience dramatic quadriceps strength loss after total knee replacement, which contributes to persistent weakness and reduced long-term function after surgery. Neuromuscular electrical stimulation (NMES) reduces quadriceps weakness and improves patient function after knee replacement, but it is drastically underused in rehabilitation practice. This randomized trial will examine the effectiveness and feasibility of a comprehensive strategy for implementing neuromuscular electrical stimulation after knee replacement in two large healthcare organizations.

Total Knee Arthroplasty (TKA) reduces pain and disability caused by knee osteoarthritis, but the surgery results in substantial trauma to the knee. This acute trauma exacerbates underlying weakness-especially in the quadriceps. This leads to muscle atrophy and likely contributes to the long-term weakness and disability patients with TKA experience relative to their healthy peers. Attenuating quadriceps strength loss should be a primary target for improving rehabilitation outcomes after TKA.

Neuromuscular electrical stimulation (NMES) is recommended in TKA clinical practice guidelines to attenuate quadriceps strength loss. In controlled settings, NMES has established efficacy and attenuates quadriceps strength loss by 40% in the first month after surgery by overriding muscle activation deficits and reducing muscle atrophy. However, the effectiveness of NMES after TKA has not been adequately studied in real-world clinical settings, and preliminary data suggests that less than 4% of rehabilitation clinicians are using NMES as recommended by current TKA practice guidelines.

To address this gap, the investigators will conduct a cluster randomized trial in two healthcare systems (UCHealth and Intermountain Health) and their associated outpatient physical therapy clinics (n=30) to evaluate the effectiveness and implementation of NMES to address musculoskeletal deficits after TKA.

The investigators will compare outcomes between patients who receive contemporary rehabilitation supported by a comprehensive NMES implementation strategy (NMES) to patients who receive contemporary musculoskeletal rehabilitation alone (Usual Care; Aim 1). The investigators will gather information on NMES implementation to promote its uptake and translation to clinical practice (Aim 2).

Inclusion Criteria:

Site Inclusion Criteria:

• UCHealth or Intermountain Health outpatient physical therapy clinic

Patient Inclusion Criteria:

• Underwent primary unilateral TKA
• Attended outpatient rehabilitation at a participating clinic within 5 days after TKA
• Attended at least 3 total outpatient physical therapy visits in total

Exclusion Criteria:

Patient Exclusion Criteria:

• NMES Contraindications [Patients with implanted cardiovascular cardiovertedefibrillator (ICD), active cancer, post-operative diagnosed deep vein thrombosis (DVT) in involved lower extremity]
• Previous lower extremity arthroplasty less than 12 weeks prior to scheduled TKA surgical date

The study team guarantees that all data collected as part of this project will be released in accordance with standard data sharing policies and procedures to validate research findings if requested. Data will be made available in a timely manner to the broader scientific community, and will be complete, and as accurate as possible. All data released will be de-identified, with no information that could be linked to any study subjects, or participating study practices to ensure the confidentiality of all subjects and practices. If necessary, a data use agreement will be established.

The data will be made available 12 months after primary study publication

Data will be made available upon reasonable written request to the study team. The PI, Dr. Jennifer Stevens-Lapsley will review requests.

Investigators will not be blinded to the arms due to facility/clinician training required for this study design. Study sites (i.e., outpatient physical therapy clinics) will be the unit of randomization. Study sites will be made broadly aware of the study initiative during the site recruitment process; however, the site will not be provided with detailed information about the intervention unless randomized to the Intervention arm. As such, clinicians, or rehabilitation care providers, at usual care sites will remain blinded to the intervention for the duration of the study. Clinicians will collect patient-level functional outcomes as part of their standard of care and all patients who are subjects of the intervention will not be aware of the group allocation in the study.