Glenoid morphology classification and computed tomography scanning prior to total shoulder arthroplasty: a population-level analysis from the Australian Orthopaedic Association National Joint Replacement Registry.

BACKGROUND

Evaluation of glenoid and humeral morphology is important prior to total shoulder arthroplasty and commonly measured on standard radiographs with further evaluation by computed tomography (CT). This study analyzed data from the Australian Orthopaedic Association National Joint Replacement Registry to assess the effect of glenoid morphology and preoperative CT scan on short-term implant survivorship.

METHODS

The Australian Orthopaedic Association National Joint Replacement Registry identified all primary total stemless and stemmed anatomic total shoulder arthroplasties (aTSAs) and reverse total shoulder arthroplasties (rTSA) undertaken for all diagnoses during the period April 2004 to December 2022. The study population was grouped into glenoid morphology classified according to the Walch classification and to those with or without preoperative CT scan. The cumulative percent revision, which was defined using Kaplan-Meier estimates of survivorship to describe the time to the first revision, was calculated based upon glenoid morphology and CT scan availability. Hazard ratios from Cox proportional hazards models, adjusting for age and sex, were performed to compare the revision rates among groups.

RESULTS

There were 4071 (10.7%) primary stemmed aTSA, 3196 (8.4%) stemless aTSA and 30,702 (80.9%) primary rTSA included. Of these, 2694 (77%), 2543 (88.6%) and 21,007 (83.8%) patients had a preoperative CT scan, respectively. There was no difference in the cumulative percent revision at any time point between glenoid type A or B for any arthroplasty type. Glenoid morphology (type A or B) alone and in conjunction with a preoperative CT scan (yes or no) did not affect the revision rate in any combination for any arthroplasty type based on hazard ratio.

CONCLUSION

Preoperative glenoid morphology and preoperative CT scanning does not affect the early rate of revision of stemmed or stemless aTSA and rTSA. Future evaluations of CT scanning in this setting should consider other performance indicators such as patient reported outcome measures.