How common are acromial and scapular spine fractures after reverse shoulder arthroplasty?: A systematic review.

AIMS: Acromial fractures following reverse shoulder arthroplasty (RSA) have a wide range of incidences in reported case series. This study evaluates their incidence following RSA by systematically reviewing the current literature. MATERIALS AND METHODS: A systematic review using the search terms "reverse shoulder", "reverse total shoulder", or "inverted shoulder" was performed using PubMed, Web of Science, and Cochrane databases between 1 January 2010 and 31 March 2018. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. Studies were included if they reported on RSA outcomes and the incidence rate of acromial and/or scapular spine fractures. The rate of these fractures was evaluated for primary RSA, revision RSA, RSA indications, and RSA implant design. RESULTS: The review included 90 articles out of 686 identified after exclusions. The incidence rate of acromial and/or scapular spine fractures was 2.8% (253/9048 RSAs). The fracture rate was similar for primary and revision RSA (2.8% vs 2.1%; p = 0.4). Acromial fractures were most common after RSA for inflammatory arthritis (10.9%) and massive rotator cuff tears (3.8%). The incidence was lowest in RSA for post-traumatic arthritis (2.1%) and acute proximal humerus fractures (0%). Lateralized glenosphere design had a significantly higher rate of acromial fractures compared with medial glenosphere designs. CONCLUSION: Based on current English literature, acromial and/or scapular spine fractures occur at a rate of 2.8% after RSA. The incidence is slightly more common after primary compared with revision arthroplasty. Also, higher rates of acromial fractures are reported in RSA performed for inflammatory arthritis and in the lateralized glenoid design. Cite this article: Bone Joint J 2019;101-B:627-634.

Does having a rotator cuff repair prior to reverse total shoulder arthroplasty influence the outcome?

AIMS: The number of rotator cuff repairs that are undertaken is increasing. Reverse shoulder arthroplasty (RSA) is the procedure of choice for patients with rotator cuff arthropathy. We sought to determine whether patients who underwent rotator cuff repair and subsequent RSA had different outcomes compared with a matched control group who underwent RSA without a previous rotator cuff repair. PATIENTS AND METHODS: All patients with a history of rotator cuff repair who underwent RSA between 2000 and 2015 with a minimum follow-up of two years were eligible for inclusion as the study group. Outcomes, including the American Shoulder and Elbow Surgeons (ASES) scores, were compared with a matched control group of patients who underwent RSA without having previously undergone rotator cuff repair. RESULTS: The study group included 45 patients. Their mean age was 69 years (sd 8.6) and 27 patients (60%) were women. The mean ASES score improved from 43.1 to 76.6 two years postoperatively, and to 66.9 five years postoperatively. There was no significant difference between the outcomes at two years in the two groups (all p ≥ 0.05), although there was significantly more improvement in ASES scores in the control group (44.5 vs 33.4; p = 0.01). However, there was no significant difference between ASES scores at two and five years when baseline ASES scores were matched in the two groups (p = 0.42 at two years; p = 0.35 at five years). CONCLUSION: Significant improvements in ASES scores were seen following RSA in patients who had previously undergone rotator cuff repair. They had higher baseline ASES scores than those who had not previously undergone this surgery. However, there was no significant difference in outcomes between the two groups, two years postoperatively. Previous rotator cuff repair does not appear to affect the early outcome after RSA adversely.

Effect of pre-operative expectations on the outcomes following total shoulder arthroplasty.

AIMS: Few studies have evaluated the relationship between patients' pre-operative expectations and the outcome of orthopaedic procedures. Our aim was to determine the effect of expectations on the outcome after primary anatomical total shoulder arthroplasty (TSA). We hypothesised that patients with greater expectations would have better outcomes. PATIENTS AND METHODS: Patients undergoing primary anatomical TSA completed the Hospital for Special Surgery's Shoulder Expectations Survey pre-operatively. The American Shoulder and Elbow Surgeons (ASES), Shoulder Activity Scale (SAS), Short-Form-36 (SF-36), and visual analogue scale (VAS) for pain, fatigue, and general health scores were also collected pre-operatively and two years post-operatively. Pearson correlations were used to assess the relationship between the number of expectations and the outcomes. Differences in outcomes between those with higher and lower levels of expectations for each expectation were assessed by independent samples t-test. Multivariable linear regression analysis was used to control for potential confounding factors. RESULTS: A total of 67 patients were evaluated two years post-operatively. Most parameters of outcome improved significantly from baseline and most patients were satisfied. A greater number of expectations was associated with a significantly greater improvement in the ASES score (p = 0.02). In the multivariable analysis, a greater number of expectations was an independent predictor of better ASES, VAS and SF-36 scores, as well as improvements in ASES and VAS pain scores (p < 0.05). Greater expectations for many specific expectation questions were significantly associated with better outcomes (p < 0.05). CONCLUSION: TSA is a successful procedure with significant improvements in outcome, and greater pre-operative expectations are associated with better outcomes. Cite this article: Bone Joint J 2017;99-B:1190-6.

Preoperative planning for accurate glenoid component positioning in reverse shoulder arthroplasty.

BACKGROUND: Glenoid component positioning in reverse shoulder arthroplasty (RSA) is challenging. Patient-specific instrumentation (PSI) has been advocated to improve accuracy, and is based on precise preoperative planning. The purpose of this study was to determine the accuracy of glenoid component positioning when only the glenoid surface is visible, compared to when the entire scapula is visible on a 3D virtual model. METHODS: CT scans of 30 arthritic shoulders were reconstructed in 3D models. Two surgeons then virtually placed a glenosphere component in the model while visualizing only the glenoid surface, in order to simulate typical intraoperative exposure ("blind 3D" surgery). One surgeon then placed the component in an ideal position while visualizing the entire scapula ("visible 3D" surgery). These two positions were then compared, and the accuracy of glenoid component positioning was assessed in terms of correction of native glenoid version and tilt, and avoidance of glenoid vault perforation. RESULTS: Mean version and tilt after "blind 3D" surgery were +1.4° (SD 8.8°) and +7.6° (SD 6°), respectively; glenoid vault perforation occurred in 17 specimens. Mean version and tilt after "visible 3D" surgery were +0.3° (SD 0.8°) and +0.1° (SD 0.5°), respectively, with glenoid vault perforation in 6 cases. "Visible 3D" surgery provided significantly better accuracy than "blind 3D" surgery (P<0.05). CONCLUSION: When the entire scapula is used as reference, accuracy is improved and glenoid vault perforation is less frequent. This type of visualization is only possible with pre-operative 3D CT planning, and may be augmented by PSI. LEVEL OF EVIDENCE: Basic science study. Level III.

Anterior deltoid deficiency in reverse total shoulder replacement: a biomechanical study with cadavers.

Reverse total shoulder replacement (RTSR) depends on adequate deltoid function for a successful outcome. However, the anterior deltoid and/or axillary nerve may be damaged due to prior procedures or injury. The purpose of this study was to determine the compensatory muscle forces required for scapular plane elevation following RTSR when the anterior deltoid is deficient. The soft tissues were removed from six cadaver shoulders, except for tendon attachments. After implantation of the RTSR, the shoulders were mounted on a custom-made shoulder simulator to determine the mean force in each muscle required to achieve 30° and 60° of scapular plane elevation. Two conditions were tested: 1) Control with an absent supraspinatus and infraspinatus; and 2) Control with anterior deltoid deficiency. Anterior deltoid deficiency resulted in a mean increase of 195% in subscapularis force at 30° when compared with the control (p = 0.02). At 60°, the subscapularis force increased a mean of 82% (p < 0.001) and the middle deltoid force increased a mean of 26% (p = 0.04). Scapular plane elevation may still be possible following an RTSR in the setting of anterior deltoid deficiency. When the anterior deltoid is deficient, there is a compensatory increase in the force required by the subscapularis and middle deltoid. Attempts to preserve the subscapularis, if present, might maximise post-operative function.