Association of handgrip strength with patient-reported outcome measures after total hip and knee arthroplasty

About 33% patients with osteoarthritis undergoing total hip/knee arthroplasty are not satisfied with the outcome, warranting the need to improve patient selection. Handgrip strength (HGS) has been suggested as a proxy for overall muscle strength and may be associated with post-arthroplasty function. This study aims to assess the association of pre-operative HGS with change in hip/knee function and quality of life in patients with arthroplasty. 226 hip (THA) and 246 knee (TKA) arthroplasty patients were included in this prospective cohort study. Pre-operative HGS was assessed by means of a dynamometer and the HOOS/KOOS and SF-36 questionnaires were collected before arthroplasty and 1 year thereafter. The association of HGS with score change on each sub-domain of the included questionnaires was assessed by linear regression models, adjusting for sex, body mass index and baseline score. Mean pre-operative HGS was 26 kg for patients undergoing THA and 24 kg for those undergoing TKA. HGS was positively associated with an increased improvement score on "function in sport and recreation"-domain in hip (β = 0.68, P = 0.005) and knee (β = 0.52, P = 0.049) and "symptoms"-domain in hip (β = 0.56, P = 0.001). For patients with THA, HGS was associated with the "quality of life" domain (β = 0.33, P = 0.033). In patients with TKA, HGS was associated with the physical component score (β = 0.31, P = 0.001). All statistically significant effects were positive, indicating that with greater pre-operative HGS, an increased gain in 1-year post-surgery score was observed. HGS can be used as a tool to inform patients with OA who are future candidates for a prosthesis about the possible improvements of certain aspects of life after arthroplasty.