The ADLER score: how to quantify and qualify deficits of external rotation

Patients with massive irreparable rotator cuff tears sometimes experience significant functional impairment due to external rotation deficits, categorized as isolated loss of external rotation (ILER) or combined loss of elevation and external rotation (CLEER). Existing shoulder measurement tools primarily assess range of motion or power, overlooking specific deficits in activities of daily living (ADLs) related to external rotation. The ADLER (Activities of Daily Living in External Rotation) score was developed to address this gap, focusing on active external rotation disability. The aim of the study was to validate the ADLER score using the Kirshner and Guyatt framework, encompassing item selection, scaling, reduction, reliability, validity, and responsiveness. The target population included patients with ILER or CLEER, identified with specific clinical signs (external rotation lag, dropping arm, and Hornblower's sign) and CT arthrogram or MRI-confirmed irreparable rotator cuff tears with Goutallier grade 3 or 4 fatty infiltration of infraspinatus and teres minor. Ten items were derived from patient-reported deficits, each scored from 0 to 3 (total 30 points). Interobserver reliability was assessed in 13 patients by 2 blinded orthopedic surgeons using Pearson correlation coefficient and intraclass correlation coefficient (ICC). Validity was evaluated against the Constant-Murley Score and Subjective Shoulder Value (SSV), and responsiveness was measured by comparing pre- and postoperative scores following L'Episcopo tendon transfer (7 tendon transfers alone and 6 with reverse shoulder arthroplasty). The ADLER score demonstrated excellent interobserver reliability (Pearson r = 0.98, P < .001; ICC = 0.98, 95% confidence interval: 0.948-0.993, P < .001) with a mean absolute difference of 1.23. Validity was confirmed through face and construct validity, with prior data showing a significant postoperative improvement (mean ADLER score from 4 to 27, P < .05) correlating with Constant-Murley and SSV outcomes. Responsiveness was evident, with a mean functional improvement of 23 points (P < .05) across 3 studies, reflecting enhanced ADLs postintervention. The ADLER score is a reliable, valid, and responsive surgical tool for assessing external rotation deficits in ADLs, applicable not only to patients undergoing reverse shoulder arthroplasty with L'Episcopo transfers but also to various procedures addressing external rotation deficits, such as latissimus dorsi or lower trapezius transfers.