Yoshihiro Hirakawa

Massive posterosuperior rotator cuff tears remain challenging because of the high retear rate after arthroscopic repair. Muscle advancement has been reported as an effective technique for reducing repair tension and improving healing in severely retracted supraspinatus and infraspinatus tendons. Although all‐arthroscopic muscle advancement has recently been reported, previously described techniques were performed in the beach‐chair position. We describe an all‐arthroscopic muscle advancement technique in the lateral decubitus position. This technical note describes the indications, technique, and technical aspects of this procedure. Indications include massive posterosuperior rotator cuff tears in which the supraspinatus and infraspinatus tendons cannot be reduced to the greater tuberosity with conventional release alone, particularly in patients without severe fatty degeneration. The procedure is performed in the lateral decubitus position using a traction device and a 30° arthroscope. Stepwise release of the supraspinatus and infraspinatus from the scapula is performed arthroscopically, followed by rotator cuff repair after sufficient advancement to the greater tuberosity is confirmed. This technique may allow anatomic reduction and low‐tension repair even in difficult‐to‐repair tears. The lateral decubitus position may provide a wider working space and improved visualization around the scapula; however, advanced arthroscopic skills and careful attention to the suprascapular nerve are required.

Background/Objectives: Accurate three-dimensional (3D) assessment of glenoid morphology depends on the coordinate system used for measurement. Conventional landmark-based coordinate systems may be affected by observer-dependent variability in identifying the scapular landmarks. This study aimed to compare the reproducibility of a novel anterior scapular plane (ASP) coordinate system with that of the conventional surgical scapular plane (SSP). Methods: Twenty-five shoulders undergoing primary reverse total shoulder arthroplasty were evaluated using preoperative computed tomography scans. Glenoid version (GV), glenoid inclination (GI), glenoid height (GH), glenoid width (GW), and global offset (GO) were measured using both coordinate systems. Two fellowship-trained shoulder surgeons independently performed all measurements twice at a 1-month interval. Intra- and inter-observer reliability were assessed using intraclass correlation coefficients (ICCs). Results: ASP demonstrated almost perfect intra- and inter-observer reliability for all parameters, with ICCs ranging from 0.888 to 0.990 and from 0.864 to 0.932, respectively. In contrast, SSP demonstrated almost perfect intra-observer reliability (ICC range, 0.815–0.963) but only substantial inter-observer reliability for GV (ICC range, 0.660–0.705) and GI (ICC range, 0.660–0.738). Using ASP, inter-observer reliability improved to 0.887–0.924 for GV and 0.898–0.932 for GI. Conclusions: The ASP coordinate system demonstrated superior reproducibility compared with the conventional SSP coordinate system for preoperative 3D evaluation of glenoid morphology. Its anatomical accuracy and applicability to postoperative assessment remain to be validated.

Background: Shoulder arthroplasty has become an increasingly important treatment option for a broad range of shoulder disorders. Although several national shoulder arthroplasty registries have been established in North America, Europe, and Australia, there is currently no well-established multicenter shoulder arthroplasty registry in Japan. To address this unmet need, researchers established the Shoulder Arthroplasty Multicenter Registry for Advanced Investigation Database (SAMURAI-DB), a multicenter clinical registry in Japan. The registry was initially launched in 2014 using paper-based case report forms and was subsequently integrated into the Research Electronic Data Capture (REDCap; Nashville, TN: Vanderbilt University) platform in 2018. The purpose of this study was to describe the design, structure, and data-collection system of SAMURAI-DB and to summarize the characteristics of procedures registered from April 2014 through December 2025. Methods: The SAMURAI-DB is a multicenter observational registry that prospectively collects clinical, surgical, radiographic, and patient-reported outcome measures (PROMs) data from patients undergoing shoulder arthroplasty. This descriptive analysis included cases registered between April 1, 2014, and December 31, 2025. Data collected included patient demographics, diagnosis, surgical procedure, implant information, complications, radiographic assessments, PROMs, and follow-up status. Registry characteristics and descriptive statistics were analyzed. Results: A total of 2,115 shoulder arthroplasties from 20 participating institutions were included in the registry. Reverse total shoulder arthroplasty (rTSA) accounted for 1,616 procedures (76.4%), followed by anatomic total shoulder arthroplasty (aTSA) (334 procedures, 15.8%) and revision rTSA (129 procedures, 6.1%). The mean age of patients undergoing rTSA was 76.9 years. The most common indications for rTSA were cuff tear arthropathy (35.1%), irreparable rotator cuff tear (31.3%), proximal humeral fracture (8.8%), and primary osteoarthritis (8.5%). Among all registered procedures eligible for each follow-up interval, outpatient visits were conducted, clinical scores were evaluated, and data were entered into the SAMURAI-DB for 70.3% of eligible procedures at six months (1,353/1,924), 76.6% at one year (1,336/1,744), and 64.8% at two years (939/1,450). Among 1,616 rTSA procedures, the most frequently recorded complications were acromial or scapular spine fracture (3.0%), instability (1.8%), implant loosening (1.6%), and periprosthetic joint infection (1.3%). Conclusions: SAMURAI-DB represents one of the first large-scale multicenter shoulder arthroplasty registries in Japan utilizing the REDCap platform. The registry enables standardized collection of longitudinal clinical, radiographic, and PROMs data across multiple institutions. The registry provides infrastructure for epidemiological research, future implant surveillance, quality improvement, and future international collaboration in shoulder arthroplasty.