Quantitative computed tomography analysis of bone microarchitecture is associated with rotator cuff healing.

Background: Rotator cuff repair in patients with osteoporosis (OP) is often hindered by poor tendon-to-bone healing and a high rate of retears, largely due to compromised bone remodeling at the repair site. However, few studies have investigated the relationship between computed tomography (CT)-based quantitative analysis of bone microarchitecture and the prognosis of rotator cuff healing.

Methods: An OP rat model was established via bilateral ovariectomy combined with dexamethasone administration. A full-thickness supraspinatus tear was surgically induced, followed by an 8-week intervention with either alendronate (ALN) or saline. Non-osteoporotic rats served as control group. Histological analysis and biomechanical testing were performed to evaluate tendon-to-bone healing. Additionally, quantitative micro-CT analysis of the humeral greater tuberosity was conducted, and correlations with tendon healing outcomes were assessed.

Results: Histological analysis at 8 weeks revealed disorganized structure and poor fibrovascular tissue in the OP group, while the OP + ALN group exhibited improved tendon-bone healing with better collagen fiber alignment and higher histological scores. A decreased RANKL/OPG ratio suggested that ALN treatment modulated regional bone metabolism in the humeral greater tuberosity. The Young's modulus was reduced in both osteoporotic groups compared to the Control group. Although the difference between the OP and OP + ALN groups was not statistically significant, a trend was observed: 50% of specimens in the OP group failed at the tendon-bone interface, compared to 33.3% in the OP + ALN group. CT analysis demonstrated that ALN treatment improved bone microarchitecture. Notably, bone microarchitectural parameters significantly correlated with histological scores of tendon healing.

Conclusion: Tendon-bone healing is impaired in the presence of OP but can be partially restored by ALN treatment. Furthermore, CT-based quantitative analysis of bone microarchitecture at the humeral greater tuberosity shows a significant correlation with rotator cuff healing. These results imply that such analysis might serve as a potential indicator of postoperative prognosis.