Dissociation of the Glenosphere: A rare Post-operative Complication of Reverse shoulder Replacement

Introduction: Reverse shoulder replacement (RSR) has been accepted as the treatment of choice for glenohumeral arthritis with irreparable rotator cuff tear. Dislocation has been a potential complication of RSR but glenosphere disengagement is a rare complication itself. There have been only few published reports of this complication in the literature. Case Report: In this case report, we have presented a case of repeated disengagement of glenoid sphere post-RSR in a 72-year-old male retired army personnel operated with Zimmer Biomet comprehensive RSR design. Conclusion: In our case scenario, we postulate that soft-tissue interposition was the reason for disengagement during first episode and was successfully relocated after removal. However, the subsequent disengagement was due to improper seating of sphere due to large central screw. Revision to a smaller central screw size appears to be the definitive solution in such case. Keywords: Reverse shoulder replacement, glenosphere disengagement, glenohumeral arthritis, irreparable rotator cuff tear.

CT-based volumetric assessment of rotator cuff muscle in shoulder arthroplasty preoperative planning

Aims The aim of this study was to describe a quantitative 3D CT method to measure rotator cuff muscle volume, atrophy, and balance in healthy controls and in three pathological shoulder cohorts. Methods In all, 102 CT scans were included in the analysis: 46 healthy, 21 cuff tear arthropathy (CTA), 18 irreparable rotator cuff tear (IRCT), and 17 primary osteoarthritis (OA). The four rotator cuff muscles were manually segmented and their volume, including intramuscular fat, was calculated. The normalized volume (NV) of each muscle was calculated by dividing muscle volume to the patient’s scapular bone volume. Muscle volume and percentage of muscle atrophy were compared between muscles and between cohorts. Results Rotator cuff muscle volume was significantly decreased in patients with OA, CTA, and IRCT compared to healthy patients (p < 0.0001). Atrophy was comparable for all muscles between CTA, IRCT, and OA patients, except for the supraspinatus, which was significantly more atrophied in CTA and IRCT (p = 0.002). In healthy shoulders, the anterior cuff represented 45% of the entire cuff, while the posterior cuff represented 40%. A similar partition between anterior and posterior cuff was also found in both CTA and IRCT patients. However, in OA patients, the relative volume of the anterior (42%) and posterior cuff (45%) were similar. Conclusion This study shows that rotator cuff muscle volume is significantly decreased in patients with OA, CTA, or IRCT compared to healthy patients, but that only minimal differences can be observed between the different pathological groups. This suggests that the influence of rotator cuff muscle volume and atrophy (including intramuscular fat) as an independent factor of outcome may be overestimated. Cite this article: Bone Jt Open 2021;2(7):552–561.

Description of Surgery Technique of the Lower Trapezius Transfer with Semitendinosus and Gracilis Tendon Graft for the Treatment of Massive or Irreparable Rotator Cuff Tear

Background: The current work describes a surgery technique where the autograft of hamstring tendon (semitendinosus and gracilis) was used as adjuvant in the transfer of the lower trapezius for the treatment of massive or irreparable rotator cuff tear. There is a theoretical advantage that the graft takes a greater footprint area in the greater tuberosity of the humerus corresponding to the infraspinatus, thus recreating the native anatomy more accurately.Methods: The autograft of hamstring tendon was attached to the lower trapezius through an incision of 4cm in the middle third of the scapular spine and transferred to the footprint of the infraspinatus in the greater tuberosity of the humerus, where it is attached through the second incision under the lateral acromial margin.Result: The patient was examined preoperatively and after 6 months of follow-up, and his pain, according to the Visual Analogue Scale, varied from 8 to 3, the range of motion improved in abduction from 100° to 120°, external rotation from 30° to 50° and flexion from 110° to 150°. The Shoulder Subjective Value ranged between 60 and 80% and the Disabilities of the Arm, Shoulder and Hand score went from 45 to 18.3.Conclusions: The lower trapezius transfer with autograft of hamstring tendons is a low-cost and relatively reproducible surgical technique with theoretical biomechanical and anatomic advantages that may bring about better function results.