Grip strength ratio: a grip strength measurement that correlates well with DASH score in different hand/wrist conditions

BACKGROUND Grip strength correlates with personal factors such as gender, age and nutritional status and has a good inter-rater reliability. It reflects fairly well how much people can use their hands.The Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Measure 3 is a 30-item, self-report, questionnaire that reflects the patients' opinion on their disability due to upper-limb disorders. We assessed if grip strength and grip strength ratio correlate with DASH score. METHODS In 3 groups (20 healthy volunteers, 17 patients after distal radius fractures, 12 patients with different hand/wrist conditions) grip strength and DASH scores (items 1-21, 22-30 and total) were assessed. To exclude personal factors grip strengths in the injured or non-dominant hand and grip strength ratios (grip strength in the injured or non-dominant hand divided by grip strength in the non-injured or dominant hand) were assessed too. Results were analyzed groups using Pearson Correlation Coefficients and with a multivariate ANOVA. RESULTS Grip strength ratio was 0.97 in healthy volunteers, 0.52 in patients after distal radius fracture and 0.74 in patients with various other hand/wrist disorders.Significant correlations were found between the grip strength ratio and DASH as well as DASH subsections in all groups and between DASH scores and grip strength in some. The correlations between the ratio of the grip strength (GSR) and DASH were much stronger than the correlation between grip strength and DASH. This emphasizes the value of the GSR. Age showed no correlation with grip strength ratio using a multivariate ANOVA. CONCLUSION Grip strength ratio correlates well with the DASH score in different hand and wrist conditions. It is a valuable tool to assess patients that speak a different language and have problems with the non-dominant hand and probably easier to follow over time than the DASH score, which is time consuming to fill in and process.