Measurement of Proximal Humeral Cortical Bone Thickness to Predict Intraoperative Anchor Stability in Arthroscopic Rotator Cuff Repair: A Retrospective Case-Control Study of a Reliable Radiographic Marker for Surgical Planning

Abstract

Background: Rotator cuff tears commonly cause shoulder pain and limited mobility. Despite advances in arthroscopic repair, failures persist, often due to poor proximal humeral bone quality. While magnetic resonance imaging assesses cuff tissue, bone quality at the footprint is frequently overlooked.Purpose: To evaluate whether proximal humeral mean cortical bone thickness (CBTmean) on standard anteroposterior (AP) shoulder radiographs predicts anchor stability during arthroscopic repair.Study Design: Case-control study; Level of evidence, 3.Methods: This retrospective case-control study was conducted at a tertiary orthopaedic center. A retrospective evaluation was made of a consecutive series of 228 patients (46 male, 182 female; mean age, 58.32 +/- 9.06 years) who underwent arthroscopic surgery for full-thickness rotator cuff tear between 2020 and 2025. Patients were separated into 3 groups based on intraoperative anchor stability: group 1 (stable anchors), group 2 (anchor repositioning required), and group 3 (anchor placement impossible due to poor bone quality managed with mini-open transosseous repair). CBTmean was measured on preoperative AP radiographs (radiographic CBTmean) and postoperative computed tomography (CT) scans (CT CBTmean) in unstable cases. Logistic regression and receiver operating characteristic curve analysis were used to determine CBTmean cutoff values.Results: Radiographic CBTmean was the only independent predictor of anchor instability (P = .001; odds ratio, 0.088). Cutoff values were <= 5.26 mm (sensitivity, 94.12%; specificity, 94.06%) for group 2 and <= 3.45 mm (sensitivity, 77.78%; specificity, 100%) for group 3. Age, pseudoparalysis, femoral bone mineral density (BMD), and massive tears were associated with instability, but CBTmean was most significant. CBTmean did not correlate with lumbar/femoral BMD, but radiographic and CT CBTmean showed near-perfect correlation (r = 0.992; P = .001). Intraobserver (intraclass correlation coefficient [ICC], 0.865) and interobserver (ICC, 0.898) reliability were excellent.Conclusion: Proximal humeral CBTmean on standard radiographs independently predicts anchor stability. Risk increases at <= 5.5 mm and becomes pronounced at <= 3.5 mm. Radiographic CBTmean assessment is a practical preoperative tool for predicting anchor stability and guiding surgical planning.