Title

Torques, range of motion and humeral head position in female subjects differing in levels of lateral scapula displacement and shoulder pain

Date of Completion

January 1998

Keywords

Health Sciences, Rehabilitation and Therapy|Health Sciences, Medicine and Surgery|Health Sciences, Recreation

Degree

Ph.D.

Abstract

Shoulder pathology in the overhead sport athlete has become a major area of orthopedic research. Two research areas are the relationship of lateral scapula displacement (LSD) to shoulder pain, and general factors related to shoulder pain. LSD has been associated with painful shoulders, but little effort has connected LSD with other aspects of shoulder function. Also current measurement techniques with the shoulder abducted have shown questionable reliability. Underlying contributors to shoulder pain have been studied, but their presence still needs to be supported and better understood. Therefore the purpose of this study was to investigate the reliability of superficial LSD measures with the shoulder abducted, and to determine the relationship of LSD and shoulder pain with internal to external rotation torque ratios, passive internal and external rotation, and anterosuperior humeral head position on the glenoid fossa. Twenty-nine Division II collegiate female athletes voluntarily participated. All subjects were measured superficially for LSD, internal to external torque ratios, videotaped to measure passive internal and external shoulder rotation, and radiographed twice to permit LSD measurement and humeral head position on the glenoid fossa. In the first phase of the study, the mean of three superficial LSD measures was correlated with a similar measure acquired on a radiograph. The results demonstrated a low reliability between the superficial and radiograph measure. Intratester reliability for the three superficial measures was acceptable. In second phase of the study, low and high LSD groups were identified and examined for differences in torque ratios, passive internal and external rotation and anterosuperior humeral head position. No overall significant difference was found, but the torque ratio was significantly greater in the high LSD group. Post-hoc testing revealed a significantly less passive internal rotation in the high LSD group. In the third phase of the study, subjects reporting shoulder pain were compared to painfree subjects for torque ratios, passive internal and external rotation, anterosuperior humeral position, and LSD. There was an overall significant difference between the two groups. The pain group displayed a significantly higher internal to external rotation torque ratio, inferior humeral head position and decreased passive internal rotation. ^