The effects of supervised exercise and pain neuroscience education on muscle strength and power in patients with chronic pain after total knee arthroplasty: An exploratory analysis from the NEPNEP trial.

OBJECTIVE

This study investigated the effects of neuromuscular exercises and pain neuroscience education (PNE) compared with PNE alone on muscle strength and power in patients with chronic pain after total knee arthroplasty (TKA).

DESIGN

Secondary analysis of a randomized controlled trial. Patients with chronic pain for >1-year after TKA were randomized to supervised neuromuscular exercises with PNE or PNE alone. The neuromuscular exercise group underwent 24 sessions over 12-weeks. The PNE was delivered in two 1-h group sessions, identical in the two groups. Outcomes included maximum voluntary isometric contractions for knee extensors and flexors, peak leg extension power and the Knee injury and Osteoarthritis Outcome Score (KOOS). Outcomes were measured at baseline, 3, 6, and 12-months. Analysis was conducted using repeated measures mixed models. Multivariable linear regression, with groups collapsed into one, was conducted to evaluate associations.

RESULTS

Sixty-nine participants were enrolled, 36 in the exercise and PNE group and 33 in the PNE alone group. No significant between-group differences were found in changes from baseline to 12-months for muscle strength or leg extension power. The exercise and PNE group showed significant within-group improvements in leg extension power (26.3 W, p = 0.019) and knee flexor strength (19.7 N, p = 0.001), which was not observed in the PNE alone group. No significant associations were found between changes in muscle strength or power and changes in KOOS.

CONCLUSIONS

Neuromuscular exercises and PNE do not seem to provide superior improvements in muscle strength or power compared to PNE alone in patients with chronic pain after TKA.

TRIAL REGISTRY: The trial was pre-registered at ClinicalTrials.gov (NCT03886259).