Constant score in asymptomatic shoulders varies with different demographic populations: derivation of adjusted score equation

BACKGROUND: In the present study, the age- and sex-adjusted Constant score (CS) in a normal Indian population was calculated and any differences with other population cohorts assessed. METHODS: The study participants were patients who visited the outpatient department for problems other than shoulder and healthy volunteers from the local population. Patients without shoulder pain/discomfort during activity were included in the study. Subjects with any problem that might affect shoulder function (e.g., cervical, thoracic spine, rib cage deformity, inflammatory arthritis) were excluded. Constant scoring of all participants was performed by trained senior residents under the supervision of the senior faculty. Shoulder range of movement and strength were measured following recommendations given by the research and Development Committee of the European Society for Shoulder and Elbow Surgery (2008). A fixed spring balance was used for strength measurement; one end was fixed on the floor and the other end tied with a strap to the wrist of the participant, arm in 90° abduction in scapular plane with palm facing down. RESULTS: Among the 248 subjects (496 shoulders), the average age was 37 years (range, 18–78 years), 65.7% were males (326 shoulders) and 34.3% females (170 shoulders). The mean CS was 84.6±2.9 (males, 86.1±3.0; females, 81.8±2.9). CS decreased significantly after 50 years of age in males and 40 years of age in females (p<0.05). The mean CS was lower than in previous studies for both males and females. Heavy occupation workers had higher mean CS (p<0.05). A linear standardized equation was estimated for calculating the adjusted CS for any age. CONCLUSIONS: Mean CS and its change with age differed from previous studies among various population cohorts.