Normative values of the Western Ontario Rotator Cuff (WORC) Index for the general population in the USA

Abstract

ObjectivesThere are limited data on Western Ontario Rotator Cuff (WORC) Index scores in a population without shoulder pathology. The primary purpose was to provide normative reference values for the WORC in an adult population with healthy shoulders. The secondary purpose was to identify demographic factors and comorbidities that may impact WORC scores.MethodsThe WORC survey was completed by patients and family members at a suburban outpatient orthopaedic centre. Patients with current shoulder injury or former upper extremity surgery were excluded. Percentage scores were calculated for total and subscale measures. Demographic factors and comorbidities were evaluated to identify possible risk factors for an abnormal baseline score (less than 100).ResultsThere were 988 participants (434 men, 554 women). Overall WORC median (IQR) was 98.64 (94.3 to 100). Each subscale was greater than 96 for all sex-based and age-based subgroups. Median WORC scores were greater than those reported in previous literature following surgery for shoulder pathology. Demographic risk factors for poor WORC scores included body mass index (BMI) greater than 30 (p<0.05), tobacco use (p<0.05), a history of shoulder problems (p<0.001) and a history of shoulder injections (p<0.001).ConclusionsThis study provides baseline values for the WORC survey in a US suburban population across a range of age groups, demonstrating that surgery for shoulder pathology often results in improved WORC scores, but may not return patients to baseline. Demographic risk factors for lower scores include smoking, BMI above 30, history of shoulder problems or history of shoulder injection.Level of evidenceDescriptive epidemiology study; Level of evidence: III.