Is hand grip strength a reliable indicator of clinical total knee arthroplasty outcomes?

Background: Hand grip strength (HGS) is regarded as a reliable indicator of overall strength. It has been associated with various clinical outcomes, such as mobility following orthopedic surgery. Methods: This single-center prospective observational study of a cohort of patients with advanced knee osteoarthritis treated by means of total knee arthroplasty (TKA) looked into the subjects' baseline HGS, as well as their gait patterns, their function and their quality of life (QoL), both preoperatively and at one year after surgery. Results: The 119 patients analyzed exhibited a mean baseline HGS with the dynamometer handle at positions 2 and 3 of 23.9 ± 10.0 kg and 22.4 ± 9.4 kg, respectively. Significant low (r < 0.49) to moderate (r < 0.69) positive linear correlations were observed between baseline HGS and postoperative walking speed, right leg acceleration, and step length of both legs. However, no significant correlations were found with postoperative function or QoL variables. Patients with a postoperative walking speed ≥1 m/s had significantly higher baseline HGS scores than those with a postoperative walking speed <1 m/s (p < 0.05). Additionally, baseline HGS values of 18 and 20 kg (for handle positions 2 and 3, respectively) were established as cutoff points for achieving a postoperative walking speed ≥1 m/s, based on ROC analysis. Stratifying patients based on these thresholds, only those with baseline HGS <20 kg at handle position 3 presented with significant improvements on the KOOS symptom score (p = 0.037) and the KOOS overall score (p = 0.041). Conclusions: Baseline HGS showed certain associations with postoperative walking speed and step length, but not with postoperative function or QoL.