Radiographic assessment of reverse shoulder arthroplasty: a narrative review of post-operative parameters and measurements.

Background: Reverse total shoulder arthroplasty (rTSA) has become an established treatment for degenerative and traumatic shoulder conditions. Accurate post-operative radiographic evaluation is essential for assessing implant positioning and alignment. However, considerable variability exists in how post-operative radiographs are interpreted and reported in the literature. This narrative review aimed to synthesize the current evidence on post-operative radiographic evaluation after rTSA and to summarize the most commonly reported radiographic parameters used to assess implant positioning, alignment, and shoulder reconstruction. Methods: This narrative review included studies that provided clear and comprehensive descriptions of post-operative radiographic parameters, resulting in 9 eligible studies. Radiographic measurements including the lateralization shoulder angle, distalization shoulder angle, neck-shaft angle, humeral offset, inferior glenosphere overhang, rTSA angle, filling ratio, acromiohumeral distance, and screw orientation were analyzed in relation to implant positioning and radiographic assessment. Results: The reviewed studies consistently described a range of radiographic parameters used to evaluate rTSA reconstruction on standard radiographs. Lateralization shoulder angle and distalization shoulder angle were used to quantify humeral lateralization and distalization, whereas acromiohumeral distance reflected humeral lengthening and deltoid tension. Neck-shaft angle and humeral offset described humeral reconstruction, while inferior glenosphere overhang and rTSA angle assessed glenoid component positioning. Overall, substantial heterogeneity was observed in measurement techniques and definitions across studies, limiting direct comparison and reproducibility. Conclusion: Post-operative radiographic evaluation remains a fundamental component of rTSA follow-up. Standardized interpretation of routine anteroposterior, axillary, and scapular Y radiographs may improve consistency in reporting and clinical decision-making. The development of validated and standardized radiographic parameters is essential to improve reproducibility and optimize post-operative assessment after rTSA.