Grip and Muscle Strength Dynamometry Are Reliable and Valid in Patients With Unhealed Minor Burn Wounds

Small burns are common and can cause disproportionate levels of disability. The ability to measure muscle impairment and consequent functional disability is a necessity during rehabilitation of patients. This study aimed to determine the reliability and validity of grip and muscle strength dynamometry in patients with unhealed, minor burn wounds. Grip and muscle strength were assessed three times on each side. Assessment occurred at presentation for the initial injury and again every other day (or every 5 days beyond 10 days post injury) until discharge from the service. Reliability was assessed using intraclass correlation. Minimum detectable differences were calculated for each muscle group. Validity was assessed using regression analysis, incorporating appropriate burn severity measures and patient demographics. Thirty patients with TBSA ≤15% were assessed. Both grip and muscle strength demonstrated very good reliability (intraclass correlation coefficient: 0.85-0.96). Minimum detectable differences ranged from 3.8 to 8.0 kg. Validity of both forms of dynamometry was confirmed through associations with gender for all muscle groups (P < .001). In addition, grip strength was associated with the dominant hand (P = .002) and time to assessment (P < .001). Strength was seen to improve over time in all muscle groups. Grip and muscle strength dynamometry are reliable and valid assessments of strength and are applicable for clinical use in patients who have unhealed, minor burn wounds.