BACKGROUND The natural course of and risk factors for tear progression in full-thickness rotator cuff tears (FTRCTs) have not been clarified yet. The study’s purpose was to retrospectively evaluate tear progression in FTRCTs by using magnetic resonance imaging (MRI) and to identify risk factors that are relevant to such tear progression. METHODS Between June 2010 and September 2019, a total of 345 patients with FTRCTs who had been diagnosed via MRI were treated conservatively. Of these, 48 patients who underwent post-treatment follow-up MRI were retrospectively enrolled. Tear progression was defined as significant when the tear size increased by >5 mm. RESULTS The mean MRI follow-up duration was 22 ± 14 months (range, 12-65 months). Among the 48 patients (mean age, 69 years; range, 53-81), 26 (54%) and 20 (41%) showed medial-lateral (M-L) and anterior-posterior (A-P) tear progression on MRI follow-up. Multivariate analysis revealed that MRI follow-up duration (P = .011), diabetes mellitus (P = .017), and infraspinatus muscle atrophy (P = .011) were independent risk factors for tear progression in the A-P plane. A high critical shoulder angle (P = .011) and supraspinatus (P = .024) and infraspinatus (P = .020) muscle atrophy were risk factors associated with M-L tear progression. CONCLUSION Among the assessed patients, a considerable number of FTRCTs increased in size during the follow-up period. Severe infraspinatus muscle atrophy was the independent risk factor for exacerbation of A-P and M-L tear progression. BACKGROUND Improved short-term outcomes have been demonstrated with higher surgical volume in shoulder arthroplasty. There is however, little data regarding long-term outcomes. METHOD Revision data from the Australian Orthopaedic Association National Joint Replacement Registry from 2004-2017 was analyzed according to 3 selected surgeon volume thresholds 20/yr group throughout the follow-up period (HR 1.66, 95% CI 1.21-2.28, P = .001). There was no significant difference for the primary diagnosis of fracture. CONCLUSION Lower surgical volume was associated with higher all-cause revision rates in the early postoperative period in TSA and rTSA for OA and throughout the follow-up period in rTSA for cuff arthropathy. Despite increases in the volume of shoulder arthroplasties performed in recent years, more than 78% of surgeons undertake fewer than 10 procedures per year. BACKGROUND Indications for reverse total shoulder arthroplasty (RTSA) are expanding, and more young patients are undergoing RTSA. Younger patients are expected to place increased functional demands on their shoulder, which may affect implant performance and longevity. Reports on longer-term outcomes in young patients remain limited. This study evaluates the minimum 5-year functional outcomes of RTSA in patients younger than 65 years. GM6001 purchase METHODS A retrospective review was performed using a multinational prospective shoulder arthroplasty database of a single implant system, Exactech Equinoxe (Gainesville, FL, USA). All RTSAs performed between 2007 and 2014 in patients younger than 65 years with minimum 5-year follow-up were included. Shoulder function was assessed preoperatively and at last follow-up via range-of-motion measurements and multiple patient-reported outcome measures. RESULTS Fifty-two shoulders were evaluated at an average follow-up of 6.3 years. Abduction, forward flexion, internal rotation, and Simple Shoulder Test, Constant, American Shoulder and Elbow Surgeons, University of California-Los Angeles, Shoulder Pain and Disability Index, and visual analog scale scores all showed statistically significant improvements greater than the minimum clinically important difference at the time of last follow-up. Three patients (5.8%) required revision surgery after a mean of 7.5 years and 1 more suffered an acromial stress fracture, bringing the total complication rate to 7.7%. Five patients (9.6%) demonstrated scapular notching, one of whom required revision arthroplasty. CONCLUSION RTSA provides clinically significant improvement in nearly all functional measures at a mean follow-up of 6.3 years in patients younger than 65 years. The implants appear to have good midterm survivorship; only 5.8% of patients required revision. BACKGROUND Radial head instability continues to be a challenge in the management of anterior Monteggia injuries; however, there is a paucity of literature on the factors that contribute to this instability. The aim of this biomechanical investigation was to examine the effects of ulnar angulation and soft tissue insufficiency on radial head stability in anterior Monteggia injuries. METHODS Six cadaveric arms were mounted in an elbow motion simulator. Radial head translation was measured during simulated active elbow flexion with the forearm supinated. After testing the elbows in the intact state, the ulna was osteotomized and tested at 0°, 10°, 20°, and 30° of extension angulation. To examine the effect of soft tissue insufficiency, the anterior radiocapitellar joint capsule, annular ligament, quadrate ligament, and the proximal and middle interosseous membrane (IOM) were sequentially sectioned. RESULTS There was a significant increase in anterior radial head translation with greater ulnar extension angulation. Sequential soft tissue sectioning also significantly increased anterior radial head translation. There was no increase in radial head translation with isolated sectioning of the anterior radiocapitellar joint capsule. Additional sectioning of the annular ligament and quadrate ligament slightly increased anterior radial head translation but did not reach statistical significance. Subsequent sectioning of the proximal and middle IOM resulted in significant increases in anterior radial head translation. CONCLUSION Our study demonstrates that progressive ulnar extension angulation results in an incremental increase in anterior radial head translation in anterior Monteggia injuries. Moreover, increasing magnitudes of soft tissue disruption result in greater anterior radial head instability. BACKGROUND The purpose of this study was to compare long-term outcomes, complications, and reoperation rates of primary reverse total shoulder arthroplasty (RTSA) performed at a single institution using 2 implant designs a Grammont medialized prosthesis (medialized [M] group) and a Frankle glenoid-based lateralized prosthesis (glenoid-lateralized [GL] group). METHODS Between 2004 and 2008, 100 consecutive single-institution primary RTSAs were performed by reconstructive shoulder surgeons who were not design consultants, with the aim of obtaining 10-year follow-up 56 in the M group and 44 in the GL group. Patients were followed up until death, until revision surgery, or for a minimum of 10 years. RESULTS Of 100 patients, 87 had more than 2 years’ follow-up (mean, 77 months). A subset analysis of 41 patients with an average of 10.2 years’ follow-up showed sustained long-term outcomes. RTSA provided clinical improvements without significant differences between the M and GL groups, except for improved active forward elevation in the M group (144° in M group vs.