Reverse shoulder arthroplasty is becoming a frequent treatment of choice for patients with shoulder disorders. Complication rates after reverse shoulder arthroplasty may be three-fold that of conventional total shoulder arthroplasty especially in high risk patient populations and diagnoses like revision arthroplasty, fracture sequelae, and severe glenoid bone loss. Complications include component malposition, stiffness, neurological injury, infection, dislocation or instability, acromial or scapular spine fractures, scapular notching, and loosening of implants. Recognition of preoperative risk factors and appropriate 3D planning are essential in optimizing patient outcome and intraoperative success. Failure of reverse shoulder arthroplasty is a significant challenge requiring appropriate diagnosis of the failure mode. The most common neurological injuries involve the brachial plexus and the axillary nerve due to traction, manipulation of the arm, aberrant retractor placement, or relative lengthening of the arm. Intraoperative fractures are relatively uncommon but include the greater tuberosity, acromion, and glenoid. Tuberosity fracture can be repaired intraoperatively with suture techniques, glenoid fractures may be insignificant rim fractures or jeopardise baseplate fixation and require abandoning RSA until glenoid fracture ORIF heals and then a second stage RSA. Periprosthetic infection after RSA ranges from 1 to 10% and may be higher in revision cases and frequently is Propionibacterium acnes and Staphylococcus epidermidis. Dislocation was one of the most common complications after RSA approximately 5% but with increased surgeon experience and prosthetic design, dislocation rates are approaching 1–2%. An anterosuperior deltoid splitting approach has been associated with increased stability as well as subscapularis repair after RSA. Scapular notching is the most common complication after RSA. Notching may be caused by direct mechanical impingement of the humerosocket polyethylene on the scapular neck and from osteolysis from polyethylene wear. Sirveaux classified scapular notching based on the defect size as it erodes behind the baseplate towards the central post. Acromial fractures are infrequent but more common is severely eroded acromions from CTA, with osteoporosis, with excessive lengthening, and with superior baseplate screws that penetrate the scapular spine and create a stress riser. Nonoperative care is the mainstay of acromial and scapular spine fractures. Recognizing preoperative risk factors and understanding component positioning and design is essential to maximizing successful outcomes

Scapular spine fracture is a serious complication of reverse total shoulder arthroplasty (RTSA) often caused by a fall on an outstretched arm or a forced movement to the shoulder. The incidence of scapular fractures occurring after RTSA is reported between 5.8% and 10.2%. These fractures have been classified into 3 discrete fracture patterns. Avulsion of the anterior acromion (Type I), Acromion fractures (Type II) and Scapular spine fractures (Type III). This discussion will review the incidence of these post-operative peri-prosthetic fractures of the scapula after reverse TSA and describe potential treatment options and prevention methods to avoid this complication

Crosby and Colleagues described 24 scapula fractures in 400 reverse shoulder arthroplasties and classified scapula fractures after reverse shoulder arthroplasty into 3 types. Type 1 – true avulsion fracture of acromion related to a thinned out acromion (post-acromioplaty or cuff arthropathy). A small bone fragment dislodges during reduction of RSA. Type 2 – Acromial fracture due to Acromio-clavicular (AC) joint arthrosis. They feel the lack of movement at the AC joint leads to stresses across the acromion and cause it to fracture. They recommend AC joint resection and ORIF of acromion, if the acromion is unstable. Type 3 – true scapula spine fracture caused by the superior screw acting as a stress riser. This fracture occurs about 8 months after the arthroplasty and is a true stress fracture requiring open reduction and internal fixation. Of 123 reverse shoulder arthroplasties performed from Jan 2003 to Feb 2011, a total of 6 scapula fractures were encountered post-surgery. Three were acromial fractures and three were scapula spine fractures all related to trauma. The fractures of the spine occurred between 6 months and 4 years post arthroplasty. We feel the fractures were traumatic but did occur through the posterior or superior screws from the metaglen. where stress risers developed for a fracture to occur. We found that using a sliding osteotomy of the spine of the scapula to bridge the defect of the scapula and a double-plating technique using two plates at 90 degrees to each other provides a satisfactory outcome after 3–6 months where patients can start actively elevating again. This method of treatment will be presented

Hypothesis. Reverse shoulder arthroplasty has good mid-term results for rotator cuff deficient arthritic conditions. Methods and Analysis. 103 reverse shoulder arthroplasties were performed in 91 patients from January 2003 to September 2009. Twelve patients had bilateral reverse shoulder arthroplasties. Results. Average clinical follow-up was 13 months (range 3-72 months). There were 38% left and 62% right shoulders. Sixty-eight percent were women and 32% were men. The average age was 72 years (range 47-88 years). Indications included: rotator cuff arthropathies (79%), failed previous hemiarthroplasties and total shoulder arthroplasties (9%), rheumatoid arthritis (5%). Fractures accounted for 7% of cases, including acute 4-part fractures in the elderly, revision of fractures with deficient cuffs, malunion and nonunion cases with deficient cuffs. There was a significant improvement in quality of life. The Constant Score increased by an average of 46 points. 62 radiographs were reviewed. 75% of these showed notching of the inferior glenoid, 53% had notching of the posterior glenoid, 10 % had heterotrophic ossification inferior to the glenoid, and 40% had an inferior glenoid spur. Complications included: 2 dislocations, 1 massive heterotrophic ossification, 3 deep infections, 1 loose glenoid related to a fall, 3 acromial fractures, and 3 scapula spine fractures (all trauma related). Conclusion. Reverse shoulder arthroplasty is a good salvage procedure for cuff deficient arthritic conditions. Clinical mid-term results are good, but notching inferiorly and posteriorly may lead to deterioration over time. Fractures of the scapula appear to originate from either the superior or posterior screws which act as stress risers and an external rotation force of the greater tuberosity against the spine of the scapula in a fall may contribute to these fractures

The reverse ball and socket shoulder replacement, employing a humeral socket and glenosphere, has revolutionized the treatment of patients with arthritis and rotator cuff insufficiency. The RSP (DjO Surgical, Inc., Austin, Texas) is one such device, characterized by a lateral center of rotation and approved for use in the United States since 2004. Multiple studies by the implant design team have documented excellent outcomes and low revision rates for the RSP, but other published outcomes data are relatively sparse. The objective of this study is to report on the complications and early outcomes in the first consecutive 60 RSPs implanted in 57 patients by a single shoulder replacement surgeon between 2004 and 2010. Forty-four patients were female and mean age at the time of reverse shoulder arthroplasty was 75 years (range 54 to 92 years). The RSP was used as a primary arthroplasty in 42 shoulders and to revise a failed prosthetic shoulder arthroplasty in 18 shoulders. During the study period, 365 shoulder replacements were implanted so that the RSP was used selectively, accounting for only 17% of all shoulder arthroplasties (8.4% for 2004-2007, 24.2% for 2008-2010). Most patients had pseudoparalysis and profound shoulder dysfunction so that mean pre-operative active forward elevation was to 45°, active abduction to 43°, active internal rotation to the buttock, and the mean pre-operative Simple Shoulder Test (SST) score was 1 out of 12. At final follow-up, mean active forward elevation had improved to 101° (p<0.0001), active abduction to 91° (p<0.0001), active internal rotation to the lumbosacral junction (p<0.001), and the mean final SST score was 7 out of 12. There were 16 complications in 14 patients, including 7 reoperations in 6 patients (11%): 3 closed reductions for dislocation, 2 open revisions for instability and for a dissociated liner in the same patient, one evacuation of a hematoma, and one open reduction and internal fixation of a post-operative scapular spine fracture. Two additional scapular spine or acromion fractures and one acromioclavicular joint separation developed postoperatively that impacted outcome adversely but did not require re-operation. None of the glenoid baseplates or humeral stems has been revised and no deep infections have occurred. Experience with reverse shoulder arthroplasty appears to influence the reoperation rate, as 3 of the reoperations occurred following the first 15 reverse shoulder arthroplasties. Overall improvements in active motion and self-assessed shoulder function were comparable to those reported previously. Final active motion results were somewhat lower than those reported previously, which may relate to the selection of predominately pseudoparalytic patients for reverse shoulder arthroplasty in this series. Use of the RSP device for reverse shoulder arthroplasty leads to improved motion and function in carefully selected older patients with pseudoparalysis or a failed shoulder replacement. Re-operations and complications occur but the learning curve may not be as steep as previously reported. This may relate to specific features of the implant system used in this series, as well as to surgeon experience