Radiographs Are Comparable With 3-Dimensional Computed Tomography-Based Models as a Modality for the Preoperative Planning of the Arthroscopic Lateral Acromioplasty: A Retrospective Comparative Study

PURPOSE: To compare plain radiographs with 3-dimensional (3D) computed tomography (CT) data for preoperative planning of arthroscopic lateral acromioplasty (ALA) for patients in whom ALA was performed along with arthroscopic rotator cuff repair (ARCR). METHODS: Patients older than 25 years old who underwent ALA along with ARCR in our institution between October 2019 and February 2021 were included in this study. Preoperative ALA simulations were performed on plain radiographs and 3D models based on CT data. The critical shoulder angle (CSA) was compared between simulations based on radiographs and those based on 3D models. The ALA procedure was performed using the 3D model simulation, along with ARCR. The CSA after surgery was investigated using radiographs. RESULTS: We evaluated 11 shoulders in 10 patients. There was no significant difference between the mean preoperative CSA on radiographs and 3D models (38.0° ± 2.6° vs 38.6° ± 1.8°, respectively; P = .55). The mean CSA after 4-mm ALA simulation using radiographs was not significantly different to that using 3D models (34.1° ± 2.6° vs 34.3° ± 2.5°, respectively; P = .84). Four cases (36.4%) required 8-mm ALA to reduce the CSA to <35° on radiographic analysis, and 2 (18.2%) required 8-mm ALA on 3D model analysis. The mean CSA on postoperative radiographs was significantly smaller than that on preoperative radiographs (32.1° ± 2.7° vs 38.0° ± 2.6°, respectively; P < .01). CONCLUSIONS: There was no significant difference between the mean CSA after a 4-mm ALA simulation using radiographs and that using 3D models based on preoperative CT data, which suggests that radiographs are comparable with 3D CT data models as a reliable modality for the preoperative simulation of ALA. LEVEL OF EVIDENCE: III, retrospective comparative study.