Journal of Orthopaedic Research - 2026-04-01 - Journal Article
A Novel Dual-Energy X-Ray Absorptiometry Protocol for the Proximal Humerus Reveals a Fatty Infiltration Dependent Reduction in Bone Mineral Density.
Cho JW, Kim DM, Oh S, Hyunchul Jo C
Topics
Key Takeaway
A novel bilateral shoulder DXA protocol in 224 rotator cuff repair patients identifies a proximal humerus osteoporosis threshold of 0.478 g/cm² (corresponding to femoral neck T-score of -2.17), with significant BMD reduction in the medial humeral head (R2, p<0.001) that progresses from periarticular to diffuse with advancing fatty infiltration grade.
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Summary
This study developed a five-region proximal humerus DXA protocol applied bilaterally in 224 patients undergoing unilateral arthroscopic rotator cuff repair to quantify regional BMD differences and their relationship to supraspinatus fatty infiltration grade. The affected shoulder showed significant BMD reduction in the medial humeral head (R2, p<0.001) and averaged humeral head (R234, p=0.011), with Goutallier Grades 3-4 associated with diffuse loss across all regions versus periarticular loss in Grades 0-2. Femoral neck T-score correlated moderately with humeral head BMD (r=0.66) but was insufficient as a standalone diagnostic tool, with a derived proximal humerus osteoporosis threshold of 0.478 g/cm².
Key Limitation
No postoperative outcomes (retear rate, anchor pullout, functional scores) were reported, so the clinical consequence of the identified BMD thresholds on repair integrity remains entirely unestablished.
Original Abstract
Localized reduction in bone mineral density (BMD) within the proximal humerus may compromise anchor fixation strength and tendon-to-bone healing after rotator cuff repair; however, standardized dual-energy X-ray absorptiometry (DXA) protocols and diagnostic thresholds are lacking. This study aimed to develop a reproducible proximal humerus DXA protocol, evaluate regional BMD differences between affected and contralateral shoulders, and investigate the relationship between fatty infiltration and regional bone loss. A retrospective analysis was performed on 224 patients who underwent unilateral arthroscopic rotator cuff repair with preoperative bilateral shoulder DXA scans. The proximal humerus was divided into five anatomically defined regions of interest (R 1 -R 5 ), and subgroup analysis was conducted according to supraspinatus fatty infiltration grade. The affected shoulder demonstrated lower BMD across all regions, although significant reductions were observed only in the medial humeral head (R 2 , p < 0.001) and averaged humeral head BMD (R 234 , p = 0.011). Patients with mild fatty infiltration (Grades 0-2) showed BMD reduction primarily in periarticular regions, whereas advanced fatty infiltration (Grades 3-4) was associated with diffuse BMD loss across all regions. Femoral neck T-score was moderately correlated with humeral head BMD (r = 0.66, R 2 = 0.488, p < 0.001), and regression analysis identified a proximal humerus osteoporosis threshold of 0.478 g/cm 2 , corresponding to a femoral neck T-score of -2.17. This protocol enables reproducible regional BMD assessment and demonstrates fatty infiltration-dependent bone loss progression. Femoral neck DXA may serve as a screening tool but is insufficient for definitive diagnosis.