Description

Background and rationale:

Large-to-massive posterosuperior rotator cuff tears with severe fatty infiltration, muscle atrophy or tendon retraction often allow only incomplete repair, and retear rates after repair remain high. Two augmentation strategies have been described separately: partial superior capsule reconstruction using the rerouted long head of the biceps tendon (LHBT), and patch augmentation with an acellular dermal matrix (ADM). Direct clinical evidence for the combination of the two techniques is not yet available; the rationale of this study is based on indirect evidence from each component technique.

Design

Prospective, single-center, single-arm case series (level of evidence IV) conducted at Tam Anh General Hospital, Ho Chi Minh City, as the clinical component of a doctoral dissertation at Hue University of Medicine and Pharmacy. A separate cadaveric biomechanical study within the same dissertation does not involve human participants and is not part of this registration.

Eligibility is assessed in two steps. Preoperative criteria are assessed clinically and on MRI. Intraoperative criteria (tear size, footprint coverage after maximal repair, and suitability of the LHBT for transposition) are confirmed arthroscopically. Participants who consented but do not meet the intraoperative criteria receive the most appropriate alternative procedure, are informed after surgery, and are not included in the analysis.

Intervention

The surgery under general anesthesia combined with interscalene block, in the lateral decubitus position, and is performed by a single surgeon (H.V.D.A). After release of adhesions and footprint preparation, the LHBT is released from the bicipital groove and fixed to the superior greater tuberosity with a suture anchor. The rotator cuff is repaired with medial-row anchors (margin convergence and footprint medialization up to 10 mm when needed). An ADM graft (MegaDerm Plus, L\&C Bio; 2 mm thick; sized intraoperatively) is passed over the repair on the medial-row sutures and fixed laterally with a suture-bridge configuration using knotless lateral-row anchors.

MegaDerm Plus is registered in Vietnam as a Class D medical device (registration certificate No. 2501939ĐKLH/BYT-HTTB, issued 06 June 2025) and is used within its registered clinical use.

All participants follow the same phased postoperative rehabilitation protocol with defined criteria for progression between phases.

Follow-up and assessments:

Clinical assessments (VAS pain, Constant-Murley, ASES and UCLA scores, range of motion and shoulder strength) are performed preoperatively and at 3, 6 and 12 months after surgery. Radiographs are taken pre-operatovely and at 3 months to measure the acromiohumeral distance. MRI is performed preoperatively and at 3 and 12 months postoperatively. Tendon integrity is graded with the Sugaya classification; Sugaya type IV or V is defined as retear. MRI measurements are read independently by two radiologists, and inter-observer agreement is reported (kappa/ICC). Adverse events, including graft-related adverse events, are monitored throughout the 12-month follow-up.

Sample size and statistical analysis:

The study is descriptive and is not powered for a comparison with historical controls. The sample size was chosen to estimate the retear rate with acceptable precision: with 33 evaluable participants and no observed retear, the upper limit of the 95% confidence interval (rule of three) would be about 9%. Allowing approximately 10-15% loss to follow-up, 40 participants will be enrolled. The retear rate is reported as a proportion with its 95% confidence interval. Pre- and postoperative clinical scores are compared with paired t-tests or Wilcoxon signed-rank tests. Factors associated with retear and functional improvement (age, sex, tear size, Goutallier grade, RoHI score) are explored with linear or logistic regression. Analyses are performed in IBM SPSS with p \< 0.05 considered significant.

Ethics

The protocol was approved by the Ethics Committee in Biomedical Research of Tam Anh General Hospital, Ho Chi Minh City (study code HV.26.09) and by the Ethics Committee of Hue University of Medicine and Pharmacy. Written informed consent is obtained from all participants. The study follows the Declaration of Helsinki and Good Clinical Practice.