Shoulder kinematics in subjects with frozen shoulder

Objectives: To describe 3-dimensional humeral motion in subjects with frozen shoulder and to determine whether a consistent capsular pattern of restriction was present.

Design: Descriptive study including repeated measurements of shoulder kinematics.

Setting: Motion-analysis laboratory.

Participants: Ten (9 women, 1 man) volunteers with a diagnosis of idiopathic adhesive capsulitis and 10 (9 women, 1 man) subjects with asymptomatic shoulders as comparison subjects.

Interventions: Not applicable.

Main outcome measures: Electromagnetic tracking sensors monitored the 3-dimensional position of the trunk, scapula, and humerus throughout active shoulder motions. Peak humeral positions relative to the trunk and scapula were determined for shoulder flexion, abduction, scapular plane abduction, external rotation (ER), and internal rotation (IR). Descriptive statistics (means, standard deviations, percentage of normal) were calculated and capsular patterns described.

Results: For humeral position relative to the trunk, subjects' mean peak motion was as follows: abduction, 98.4 degrees; ER at the side, 4.5 degrees; ER with the arm abducted, 33.5 degrees; flexion, 116.9 degrees; IR at the side, 54.3 degrees; IR with the arm abducted, 17.8 degrees; and scapular plane abduction, 113.4 degrees. For humeral position relative to the scapula, subjects' mean peak motion was as follows: abduction, 46.4 degrees; ER at the side, 34.7 degrees; ER with the arm abducted, 45.3 degrees; flexion, 70.5 degrees; IR at the side, 10.3 degrees; IR with the arm abducted, -6.4 degrees; and scapular plane abduction, 61.7 degrees.

Conclusions: Symptomatic subjects demonstrated substantial kinematic deficits during humeral range of motion. No single capsular pattern emerged.