Discordance between patient-reported and objectively measured internal rotation after reverse shoulder arthroplasty

Predictors of Internal Rotation-Dependent Activities of Daily Living Performance and Favorable Satisfaction Despite Loss of Objective Internal Rotation After Reverse Shoulder Arthroplasty

INTRODUCTION

Previous research has determined that objective and subjective internal rotation (IR) may be discordant. The purpose of this study was to identify predictors of patient-reported ability to perform IR-dependent activities of daily living (IRADLs) and favorable patient satisfaction after reverse shoulder arthroplasty (RSA) despite the loss of objective IR.

METHODS

A single, institutional, shoulder arthroplasty database was queried for patients undergoing primary RSA with a minimum 2-year follow-up. Patients who were wheelchair bound or had a preoperative diagnosis of infection, fracture, or tumor were excluded. We first identified patients in the overall cohort that lost objective IR from pre- to postoperative assessment, defined as a one-point reduction in the eight-point Flurin scale. In this cohort, we identified patient characteristics that were predictive of patient-reported ability to perform IRADLs and overall patient satisfaction and thresholds in postoperative objective IR.

RESULTS

Out of 599 RSAs initially identified, 107 RSAs lost objective IR (45% female, mean age 70 years). On average, patients lost 1.7 IR score points pre- to postoperatively. Greater preoperative IR and lesser loss of objective IR pre- to postoperatively were associated with greater patient-reported ability to perform all 4 IRADLs (odds ratio 1.54 to 2.5), whereas female sex was associated with worse patient-reported ability to perform 3 IRADLs (odds ratio 0.26 to 0.36). We identified that patients with postoperative IR below the sacrum were unlikely to be able to perform IRADLs and those with postoperative IR at or above L4-L5 were likely to be satisfied.

CONCLUSION

Despite losing objectively assessed IR after RSA, many patients are still able to perform IRADLs and report favorable satisfaction as long as objective IR reaches L4/5. Female sex and postoperative IR below the sacrum were associated with the inability to perform IRADLs, whereas postoperative IR to or above L4-L5 was associated with subjective ratings of satisfaction.

Lateralising reverse shoulder arthroplasty using bony increased offset (BIO-RSA) or increasing glenoid component diameter: comparison of clinical, radiographic and patient reported outcomes in a matched cohort

BACKGROUND

This study aims to compare the range of motion (ROM) of reverse shoulder arthroplasty lateralised by bony increased offset (BIO-RSA) using a standard 38-mm (mm) component to regular reverse shoulder arthroplasty (RSA) lateralised by using a 42-mm glenoid component. The secondary aims are to compare patient-reported and radiographic outcomes between the two groups.

MATERIALS AND METHODS

All patients with a BIO-RSA and size 38 glenosphere were retrospectively identified and matched to patients with a regular RSA and size 42 glenosphere. Matched patients were invited for a follow-up visit. ROM was assessed as well as radiographic outcomes (lateralisation, distalisation, inferior overhang, scapular notching, heterotopic bone formation, radiolucency, stress shielding, bone graft healing and viability and complications) and patient-reported outcomes (subjective shoulder value, Constant score, American Shoulder and Elbow Surgeons, activities of daily living which require internal rotation, activities of daily living which require external rotation and a visual analogue scale for pain). Outcomes were compared between the two groups.

RESULTS

In total, 38 BIO-RSAs with a size 38 glenosphere were matched to 38 regular RSAs with a size 42 glenosphere. Of the 76 matched patients, 74 could be contacted and 70 (95%) were included. At the final follow-up, there were no differences between the two groups in ROM, patient-reported outcomes or radiographic outcomes (p > 0.485).

CONCLUSIONS

Using a larger glenosphere is a feasible alternative to BIO-RSA for lateralising RSA, providing comparable ROM, patient-reported and radiographic results, while potentially decreasing costs, operative time and complication rates.

LEVEL OF EVIDENCE III