Quantification of posterior capsule tightness and motion loss in patients with shoulder impingement

The relationship between posterior capsule tightness and dysfunction has lo ng been recognized clinically but has not been biometrically quantified. Th e purpose of this study was to quantify changes in range of motion and post erior capsule tightness in patients with dominant or nondominant shoulder i mpingement. Measurements of posterior capsule tightness and external and in ternal rotation range of motion were made in 31 patients with shoulder impi ngement and in 33 controls without shoulder abnormality. Patients with impi ngement in the nondominant arm had increased posterior capsule tightness an d decreased internal and external rotation range of motion compared with co ntrols. Patients with impingement in their dominant arm had increased poste rior capsule tightness and reduced internal rotation range of motion but no significant loss of external rotation range of motion compared with contro ls. Posterior capsule tightness in impingement patients showed a significan t correlation with loss of internal rotation range of motion. Patients with shoulder impingement in their nondominant arm had a more global loss of ra nge of motion compared with patients having impingement in their dominant a rm. We believe we have described a valid clinical measurement for identifyi ng posterior capsule tightness in patients with shoulder impingement.