Aims. The current evidence comparing the two most common approaches for reverse total shoulder arthroplasty (rTSA), the deltopectoral and anterosuperior approach, is limited. This study aims to compare the rate of loosening, instability, and implant survival between the two approaches for rTSA using data from the Dutch National Arthroplasty Registry with a minimum follow-up of five years. Methods. All patients in the registry who underwent a primary rTSA between January 2014 and December 2016 using an anterosuperior or deltopectoral approach were included, with a minimum follow-up of five years. Cox and logistic regression models were used to assess the association between the approach and the implant survival, instability, and glenoid loosening, independent of confounders. Results. In total, 3,902 rTSAs were included. A deltopectoral approach was used in 54% (2,099/3,902) and an anterosuperior approach in 46% (1,803/3,902). Overall, the mean age in the cohort was 75 years (50 to 96) and the most common indication for rTSA was cuff tear arthropathy (35%; n = 1,375), followed by osteoarthritis (29%; n = 1,126), acute fracture (13%; n = 517), post-traumatic sequelae (10%; n = 398), and an irreparable cuff rupture (5%; n = 199). The two high-volume centres performed the anterosuperior approach more often compared to the medium- and low-volume centres (p < 0.001). Of the 3,902 rTSAs, 187 were revised (5%), resulting in a five-year survival of 95.4% (95% confidence interval 94.7 to 96.0; 3,137 at risk). The most common reason for revision was a periprosthetic joint infection (35%; n = 65), followed by instability (25%; n = 46) and loosening (25%; n = 46). After correcting for relevant confounders, the revision rate for glenoid loosening, instability, and the overall implant survival did not differ significantly between the two approaches (p = 0.494, p = 0.826, and p = 0.101, respectively). Conclusion. The surgical approach used for rTSA did not influence the overall implant survival or the revision rate for instability or glenoid loosening. Cite this article: Bone Joint J 2023;105-B(9):1000–1006

Aims. The aim of this study was to report the incidence of implant-related complications, further operations, and their influence on the outcome in a series of patients who underwent primary reverse total shoulder arthroplasty (RTSA). Methods. The prospectively collected clinical and radiological data of 797 patients who underwent 854 primary RTSAs between January 2005 and August 2018 were analyzed. The hypothesis was that the presence of complications would adversely affect the outcome. Further procedures were defined as all necessary operations, including reoperations without change of components, and partial or total revisions. The clinical outcome was evaluated using the absolute and relative Constant Scores (aCS, rCS), the Subjective Shoulder Value (SSV) scores, range of motion, and pain. Results. The overall surgical site complication rate was 22% (188 complications) in 152 patients (156 RTSAs; 18%) at a mean follow-up of 46 months (0 to 169). The most common complications were acromial fracture (in 44 patients, 45 RTSAs; 5.3%), glenoid loosening (in 37 patients, 37 RTSAs; 4.3%), instability (in 23 patients, 23 RTSAs; 2.7%), humeral fracture or loosening of the humeral component (in 21 patients, 21 RTSAs; 2.5%), and periprosthetic infection (in 14 patients, 14 RTSAs; 1.6%). Further surgery was undertaken in 79 patients (82 RTSAs) requiring a total of 135 procedures (41% revision rate). The most common indications for further surgery were glenoid-related complications (in 23 patients, 23 RTSAs; 2.7%), instability (in 15 patients, 15 RTSAs; 1.8%), acromial fractures (in 11 patients, 11 RTSAs; 1.3%), pain and severe scarring (in 13 patients, 13 RTSAs; 1.5%), and infection (in 8 patients, 8 RTSAs; 0.9%). Patients who had a complication had significantly worse mean rCS scores (57% (SD 24%) vs 81% (SD 16%)) and SSV scores (53% (SD 27%) vs 80% (SD 20%)) compared with those without a complication. If revision surgery was necessary, the outcome was even further compromised (mean rCS score: 51% (SD 23%) vs 63% (SD 23%); SSV score: 4% (SD 25%) vs 61% (SD 27%). Conclusion. Although the indications for, and use of, a RTSA are increasing, it remains a demanding surgical procedure. We found that about one in five patients had a complication and one in ten required further surgery. Both adversely affected the outcome. Cite this article: Bone Joint J 2022;104-B(3):401–407

Aims. Scapular notching is thought to have an adverse effect on the outcome of reverse total shoulder arthroplasty (RTSA). However, the matter is still controversial. The aim of this study was to determine the clinical impact of scapular notching on outcomes after RTSA. Methods. Three electronic databases (PubMed, Cochrane Database, and EMBASE) were searched for studies which evaluated the influence of scapular notching on clinical outcome after RTSA. The quality of each study was assessed. Functional outcome scores (the Constant-Murley scores (CMS), and the American Shoulder and Elbow Surgeons (ASES) scores), and postoperative range of movement (forward flexion (FF), abduction, and external rotation (ER)) were extracted and subjected to meta-analysis. Effect sizes were expressed as weighted mean differences (WMD). Results. In all, 11 studies (two level III and nine level IV) were included in the meta-analysis. All analyzed variables indicated that scapular notching has a negative effect on the outcome of RTSA . Statistical significance was found for the CMS (WMD –3.11; 95% confidence interval (CI) –4.98 to –1.23), the ASES score (WMD –6.50; 95% CI –10.80 to –2.19), FF (WMD –6.3°; 95% CI –9.9° to –2.6°), and abduction (WMD –9.4°; 95% CI –17.8° to –1.0°), but not for ER (WMD –0.6°; 95% CI –3.7° to 2.5°). Conclusion. The current literature suggests that patients with scapular notching after RTSA have significantly worse results when evaluated by the CMS, ASES score, and range of movement in flexion and abduction. Cite this article: Bone Joint J 2020;102-B(11):1438–1445

Aims

The aim of this study was to compare the clinical and radiological outcomes of reverse shoulder arthroplasty (RSA) using small and standard baseplates in Asian patients, and to investigate the impact of a mismatch in the sizes of the glenoid and the baseplate on the outcomes.

Aims. This systematic review asked which patterns of complications are associated with the three reverse total shoulder arthroplasty (RTSA) prosthetic designs, as classified by Routman et al, in patients undergoing RTSA for the management of cuff tear arthropathy, massive cuff tear, osteoarthritis, and rheumatoid arthritis. The three implant design philosophies investigated were medial glenoid/medial humerus (MGMH), medial glenoid/lateral humerus (MGLH), and lateral glenoid/medial humerus (LGMH). Methods. A systematic review of the literature was performed via a search of MEDLINE and Embase. Two reviewers extracted data on complication occurrence and patient-reported outcome measures (PROMs). Meta-analysis was conducted on the reported proportion of complications, weighted by sample size, and PROMs were pooled using the reported standardized mean difference (SMD). Quality of methodology was assessed using Wylde’s non-summative four-point system. The study was registered with PROSPERO (CRD42020193041). Results. A total of 42 studies met the inclusion and exclusion criteria. Rates of scapular notching were found to be significantly higher in MGMH implants (52% (95% confidence interval (CI) 40 to 63)) compared with MGLH ((18% (95% CI 6 to 34)) and LGMH (12% (95% CI 3 to 26)). Higher rates of glenoid loosening were seen in MGMH implants (6% (95% CI 3 to 10)) than in MGLH implants (0% (95% CI 0 to 2)). However, strength of evidence for this finding was low. No significant differences were identified in any other complication, and there were no significant differences observed in PROMs between implant philosophies. Conclusion. This systematic review has found significant improvement in PROMS and low complication rates across the implant philosophies studied. Scapular notching was the only complication found definitely to have significantly higher prevalence with the MGMH implant design. Cite this article: Bone Joint J 2021;103-B(5):813–821

Aims. Rates of reverse total shoulder arthroplasty (rTSA) continue to grow. Glenoid bone loss and deformity remains a technical challenge to the surgeon and may reduce improvements in patients’ outcomes. However, there is no consensus as to the optimal surgical technique to best reconstruct these patients’ anatomy. This review aims to compare the outcomes of glenoid bone grafting versus augmented glenoid prostheses in the management of glenoid bone loss in primary reverse total shoulder arthroplasty. Methods. This systematic review and meta-analysis evaluated study-level data in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We performed searches of Medline (Ovid), Embase (Ovid), and PubMed from their dates of inception to January 2022. From included studies, we analyzed data for preoperative and postoperative range of motion (ROM), patient-reported functional outcomes, and complication rates. Results. A total of 13 studies (919 shoulders) were included in the analysis. The mean age of patients at initial evaluation was 72.2 years (42 to 87), with a mean follow-up time of 40.7 months (24 to 120). Nine studies with 292 rTSAs evaluated the use of bone graft and five studies with 627 rTSAs evaluated the use of augmented glenoid baseplates. One study was analyzed in both groups. Both techniques demonstrated improvement in patient-reported outcome measures and ROM assessment, with augmented prostheses outperforming bone grafting on improvements in the American Shoulder and Elbow Surgeons Score. There was a higher complication rate (8.9% vs 3.5%; p < 0.001) and revision rate among the bone grafting group compared with the patients who were treated with augmented prostheses (2.4% vs 0.6%; p = 0.022). Conclusion. This review provides strong evidence that both bone graft and augmented glenoid baseplate techniques to address glenoid bone loss give excellent ROM and functional outcomes in primary rTSA. The use of augmented base plates may confer fewer complications and revisions. Cite this article: Bone Joint J 2022;104-B(12):1334–1342

The February 2023 Shoulder & Elbow Roundup. 360. looks at: Arthroscopic capsular release or manipulation under anaesthesia for frozen shoulder?; Distal biceps repair through a single incision?; Distal biceps tendon ruptures: diagnostic strategy through physical examination; Postoperative multimodal opioid-sparing protocol vs standard opioid prescribing after knee or shoulder arthroscopy: a randomized clinical trial; Graft healing is more important than graft technique in massive rotator cuff tear; Subscapularis tenotomy versus peel after anatomic shoulder arthroplasty; Previous rotator cuff repair increases the risk of revision surgery for periprosthetic joint infection after reverse shoulder arthroplasty; Conservative versus operative treatment of acromial and scapular spine fractures following reverse total shoulder arthroplasty

Aims. Both anatomical and reverse total shoulder arthroplasty (aTSA and rTSA) provide functional improvements. A reported benefit of aTSA is better range of motion (ROM). However, it is not clear which procedure provides better outcomes in patients with limited foward elevation (FE). The aim of this study was to compare the outcome of aTSA and rTSA in patients with glenohumeral osteoarthritis (OA), an intact rotator cuff, and limited FE. Methods. This was a retrospective review of a single institution’s prospectively collected shoulder arthroplasty database for TSAs undertaken between 2007 and 2020. A total of 344 aTSAs and 163 rTSAs, which were performed in patients with OA and an intact rotator cuff with a minimum follow-up of two years, were included. Using the definition of preoperative stiffness as passive FE ≤ 105°, three cohorts were matched 1:1 by age, sex, and follow-up: stiff aTSAs (85) to non-stiff aTSAs (85); stiff rTSAs (74) to non-stiff rTSAs (74); and stiff rTSAs (64) to stiff aTSAs (64). We the compared ROMs, outcome scores, and complication and revision rates. Results. Compared with non-stiff aTSAs, stiff aTSAs had poorer passive FE and active external rotation (ER), whereas there were no significant postoperative differences between stiff rTSAs and non-stiff rTSAs. There were no significant differences in preoperative function when comparing stiff aTSAs with stiff rTSAs. However, stiff rTSAs had significantly greater postoperative active and passive FE (p = 0.001 and 0.004, respectively), and active abduction (p = 0.001) compared with stiff aTSAs. The outcome scores were significantly more favourable in stiff rTSAs for the Shoulder Pain and Disability Index, Simple Shoulder Test, American Shoulder and Elbow Surgeons score, University of California, Los Angeles score, and the Constant score, compared with stiff aTSAs. When comparing the proportion of stiff aTSAs versus stiff rTSAs that exceeded the minimal clinically important difference and substantial clinical benefit, stiff rTSAs achieved both at greater rates for all measurements except active ER. The complication rate did not significantly differ between stiff aTSAs and stiff rTSAs, but there was a significantly higher rate of revision surgery in stiff aTSAs (p = 0.007). Conclusion. Postoperative overhead ROM, outcome scores, and rates of revision surgery favour the use of a rTSA rather than aTSA in patients with glenohumeral OA, an intact rotator cuff and limited FE, with similar rotational ROM in these two groups. Cite this article: Bone Joint J 2023;105-B(12):1303–1313

Aims. Existing literature indicates that inferiorly inclined glenoid baseplates following reverse total shoulder arthroplasty (RSA) produce better outcomes compared to superiorly inclined baseplates. We aim to compare clinical outcomes for RSAs with superiorly and neutrally/inferiorly inclined lateralized glenospheres. Methods. We retrospectively reviewed 154 consecutive patients undergoing RSA between July 2015 and July 2017 by one single-fellowship trained surgeon (AJ). Two raters (KAM and MVS) independently measured glenoid inclination in preoperative and minimum two year follow-up radiographs (anteroposterior/Grashey) using the RSA angle. Inclination was then compared to patient-reported outcomes, range of motion (ROM), and independently assessed degree of scapular notching and staging of heterotopic ossification at two year follow-up. Results. Median postoperative inclination for each group was found to be -3.6° (interquartile range (IQR) -2.1 to -6.9) and 6.0° (3.2° to 10.1°) for the neutrally/inferiorly and superiorly inclined cohorts, respectively. Preoperative inclination was highly associated with postoperative inclination (p = 0.004). When comparing superiorly and neutrally/inferiorly inclined glenospheres, there were no differences in heterotopic ossification (p = 0.606), scapular notching (p = 0.367), American Shoulder and Elbow Surgeons score (p = 0.419), Single Assessment Numeric Evaluation (p = 0.417), Visual Analogue Scale (VAS) pain score (p = 0.290), forward elevation (p = 0.161), external rotation (p = 0.537), or internal rotation (p = 0.656). Conclusion. Compared to neutral and inferior inclination, up to 6° ± 3° of superior glenoid baseplate inclination on a lateralized RSA design produces no differences in postoperative ROM or patient-reported outcomes, and produces similar levels of scapular notching and heterotopic ossification. Additionally, the degree of preoperative inclination represents an important factor in surgical decision-making as it is strongly associated with postoperative inclination. It is important to note that the findings of this study are only reflective of lateralized RSA prostheses. Cite this article: Bone Joint J 2021;103-B(2):360–365

The February 2024 Shoulder & Elbow Roundup. 360. looks at: Does indomethacin prevent heterotopic ossification following elbow fracture fixation?; Arthroscopic capsular shift in atraumatic shoulder joint instability; Ultrasound-guided lavage with corticosteroid injection versus sham; Combined surgical and exercise-based interventions following primary traumatic anterior shoulder dislocation: a systematic review and meta-analysis; Are vascularized fibula autografts a long-lasting reconstruction after intercalary resection of the humerus for primary bone tumours?; Anatomical versus reverse total shoulder arthroplasty with limited forward elevation; Tension band or plate fixation for simple displaced olecranon fractures?; Is long-term follow-up and monitoring in shoulder and elbow arthroplasty needed?

Abstract. Objective. To investigate the safety and cost-effectiveness of interscalene brachial plexus block/regional anaesthesia (ISB-RA) in patients undergoing reverse total shoulder replacement. Methods. This retrospective study included 15 patients with symptomatic rotator cuff arthropathy who underwent reverse total shoulder arthroplasty (rTSA) under ISB-RA without general anaesthesia in the beach chair position from 2010 to 2018. The mean patient age was 77 years (range 59–82 years). Patients had associated medical comorbidities: American Society of Anesthesiologists (ASA) grade 2–4. Assessed parameters were: duration of anaesthesia, intra-operative systolic blood pressure variation, sedation and vasopressor use, duration of post-operative recovery, recovery scores, length of stay, and complications. A robust cost analysis was also performed. Results. The mean (range) duration of anaesthesia was 38.66 (20–60) min. Maximum and minimum intra-operative systolic blood pressure ranges were 130–210 and 75–145 mmHg, respectively (mean [range] drop, 74.13 [33–125] mmHg). Mean (range) propofol dose was 1.74 (1–3.0) mg/kg/h. The Median (interquartile range) post-operative recovery time was 30 (20–50) min. The mean (range) postoperative recovery score (local scale, range 5–28 where lower values are superior) was 5.2 (5–8). The mean (range) length of stay was 8 (1–20 days); the two included patients with ASA grade 2 were both discharged within 24 hours. One patient with predisposing history developed pneumonia; however, there were no complications related to ISB-RA. The mean (range) cost per patient was £101.36 (£59.80-£132.20). Conclusions. Our data demonstrate that rTSA under ISB-RA is safe, cost-effective and a potentially viable alternative for patients with multiple comorbidities. Notably, patients with ASA grade 2 who underwent rTSA under ISB-RA had a reduced length of stay and were discharged within 24 hours

Aims. Reverse total shoulder arthroplasty (RTSA) using trabecular metal (TM)-backed glenoid implants has been introduced with the aim to increase implant survival. Only short-term reports on the outcomes of TM-RTSA have been published to date. We aim to present the seven-year survival of TM-backed glenoid implants along with minimum five-year clinical and radiological outcomes. Methods. All consecutive elective RTSAs performed at a single centre between November 2008 and October 2014 were reviewed. Patients who had primary TM-RTSA for rotator cuff arthropathy and osteoarthritis with deficient cuff were included. A total of 190 shoulders in 168 patients (41 male, 127 female) were identified for inclusion at a mean of 7.27 years (SD 1.4) from surgery. The primary outcome was survival of the implant with all-cause revision and aseptic glenoid loosening as endpoints. Secondary outcomes were clinical, radiological, and patient-related outcomes with a five-year minimum follow-up. Results. The implant was revised in ten shoulders (5.2%) with a median time to revision of 21.2 months (interquartile range (IQR) 9.9 to 41.8). The Kaplan-Meier survivorship estimate at seven years was 95.9% (95% confidence interval (CI) 91.7 to 98; 35 RTSAs at risk) for aseptic mechanical failure of the glenoid and 94.8% (95% CI 77.5 to 96.3; 35 RTSAs at risk) for all-cause revision. Minimum five-year clinical and radiological outcomes were available for 103 and 98 RTSAs respectively with a median follow-up time of six years (IQR 5.2 to 7.0). Median postoperative Oxford Shoulder Score was 38 (IQR 31 to 45); median Constant and Murley score was 60 (IQR 47.5 to 70); median forward flexion 115° (IQR 100° to 125°); median abduction 95° (IQR 80° to 120°); and external rotation 25° (IQR 15° to 40°) Scapular notching was seen in 62 RTSAs (63.2%). Conclusion. We present the largest and longest-term series of TM-backed glenoid implants demonstrating 94.8% all-cause survivorship at seven years. Specifically pertaining to glenoid loosening, survival of the implant increased to 95.9%. In addition, we report satisfactory minimum five-year clinical and radiological outcomes. Cite this article: Bone Joint J 2021;103-B(8):1333–1338

Introduction & Aims. Over the last decade, sensor technology has proven its benefits in total knee arthroplasty, allowing the quantitative assessment of tension in the medial and lateral compartment of the tibiofemoral joint through the range of motion (VERASENSE, OrthoSensor Inc, FL, USA). In reversal total shoulder arthroplasty, it is well understood that stability is primarily controlled by the active and passive structures surrounding the articulating surfaces. At current, assessing the tension in these stabilizing structures remains however highly subjective and relies on the surgeons’ feel and experience. In an attempt to quantify this feel and address instability as a dominant cause for revision surgery, this paper introduces an intra-articular load sensor for reverse total shoulder arthroplasty (RTSA). Method. Using the capacitive load sensing technology embedded in instrumented tibial trays, a wireless, instrumented humeral trial has been developed. The wireless communication enables real-time display of the three-dimensional load vector and load magnitude in the glenohumeral joint during component trialing in RTSA. In an in-vitro setting, this sensor was used in two reverse total shoulder arthroplasties. The resulting load vectors were captured through the range of motion while the joint was artificially tightened by adding shims to the humeral tray. Results. For both shoulder specimens, the newly developed sensor provided insight in the load magnitude and characteristics through the range of motion. In neutral rotation and under a condition assessed as neither too tight nor too loose, glenohumeral loads in the range of 10–30lbs were observed. As expected, with increasing shim thickness these intra- articular load magnitudes increased. Assessing the load variations through the range of motion, high peak forces of up to 120 lbs were observed near the limits of the range of motion, most pronounced during external humeral rotation. Conclusions. In conclusion, this paper presents an intra-articular load sensor that can be used during the trialing phase in reverse total shoulder arthroplasty. A first series of cadaveric experiments provided evidence of realistic load ranges and load characteristics with respect to the end of the range of motion. Currently, effort is undertaken to develop a biomechanically validated load range that can serve as a target in surgery

Purpose. To evaluate the results of reverse total shoulder arthroplasty for complicated proximal humerus fractures in old ages. Materials and Methods. We retrospectively evaluated 13 cases who underwent reverse total shoulder arthroplasty for proximal humerus fracture, fracture-dislocation and nonunions of the fractures. Mean age was 77(68–87)years old and mean follow-up period was 15.2(12–26)months. four part fractures of proximal humerus in 7 cases, fracture-dislocation in 3 cases, locked dislocation with greater tuberosity in 2 cases, nonunion with defiency of rotator cuff in 1 case were included. We evaluated mean ASES, mean UCLA, mean KSS, mean SST and mean range of motion(ROM). Results. Postoperative mean ASES was 59(13–98.5), mean UCLA was 21(12–34), mean KSS was 62(21–94), mean SST was 5(1–11). Postoperative mean ROM was 103°(30°–135°) in forward flexion, 93°(30°–135°) in abduction, 21°(0°–45°) in external rotation and L4 level in internal rotation. The complications were not shown in any cases except for resolved heterotropic ossification. 4 cases demonstrated bony unions on greater tuberosity and 4 cases showed scapular notching on last follow-up. Conclusions. Reverse total shoulder arthroplasty for complicated proximal humerus fracture, nonunion of the fracture, or chronic locked dislocation seems to be a good treatment options. Regardless of bony union of the greater tuberosity, reverse total shoulder arthroplasty for the complicated proximal humerus fractures had a satisfied results

Purpose:. To evaluate the results of reverse total shoulder arthroplasty for complicated proximal humerus fractures in old ages. Materials and Methods:. We retrospectively evaluated 13 cases who underwent reverse total shoulder arthroplasty for proximal humerus fracture, fracture-dislocation and nonunions of the fractures. Mean age was 77 years old and mean follow-up period was 15.2(12–26) months. four part fractures of proximal humerus in 7 cases, fracture-dislocation in 3 cases, locked dislocation with greater tuberosity in 2 cases, nonunion with defiency of rotator cuff in 1 case were included (Fig. 1, Fig. 2, Fig. 3). We evaluated mean ASES, mean UCLA, mean KSS, mean SST and mean range of motion (ROM). Results:. Postoperative mean ASES was 59(13–98.5), mean UCLA was 21(12–34), mean KSS was 62(21–94), mean SST was 5(1–11). Postoperative mean ROM was 103° in forward flexion, 93° in abduction, 21° in external rotation and L4 level in internal rotation. 4 cases demonstrated bony unions on greater tuberosity and 4 cases showed scapular notching on last follow-up. Conclusion:. Reverse total shoulder arthroplasty for complicated proximal humerus fracture, nonunion of the fracture, or chronic locked dislocation seems to be a good treatment options. Regardless of bony union of the greater tuberosity, reverse total shoulder arthroplasty for the complicated proximal humerus fractures had a satisfied results. Key words: Shoulder, Proximal humerus fracture, Reverse total shoulder arthroplasty

Glenoid bone grafting in reverse total shoulder arthroplasty (RTSA) has emerged as an effective method of restoring bone stock in the presence of complex glenoid bone loss, yet there is limited published evidence on efficacy. The aim of this study was to conduct an analysis of clinical and radiographic outcomes associated with glenoid bone grafting in primary RTSA. Patients who underwent a primary RTSA with glenoid bone grafting were retrospectively identified from the databases of two senior shoulder surgeons. Inclusion criteria included minimum of 12 months clinical and/or radiographical follow up. Patients underwent preoperative clinical and radiographic assessment. Graft characteristics (source, type, preparation), range of movement (ROM), patient-reported outcome measures (Oxford Shoulder Scores [OSS]), and complications were recorded. Radiographic imaging was used to analyse implant stability, graft incorporation, and notching by two independent reviewers. Between 2013 and 2021, a total of 53 primary RTSA procedures (48 patients) with glenoid bone grafting were identified. Humeral head autograft was used in 51 (96%) of cases. Femoral head allograft was utilised in two cases. Depending on the morphology of glenoid bone loss, a combination of structural (corticocancellous) and non-structural (cancellous) grafts were used to restore glenoid bone stock and the joint line. All grafts were incorporated at review. The mean post-operative OSS was significantly higher than the pre-operative OSS (40 vs. 22, p < 0.001). ROM was significantly improved post-operatively. One patient is being investigated for residual activity-related shoulder pain. This patient also experienced scapular notching resulting in the fracturing of the inferior screw. One patient experienced recurrent dislocations but was not revised. Overall, at short term follow up, glenoid bone grafting was effective in addressing glenoid bone loss with excellent functional and clinical outcomes when used for complex bone loss in primary RTSA. The graft incorporation rate was high, with an associated low complication rate

Patients with pain and loss of shoulder function due to nonunion of a fracture of the proximal third of the humerus may benefit from reverse total shoulder replacement. This paper reports a prospective, multicentre study, involving three hospitals and three surgeons, of 35 patients (28 women, seven men) with a mean age of 69 years (46 to 83) who underwent a reverse total shoulder replacement for the treatment of nonunion of a fracture of the proximal humerus. Using Checchia’s classification, nine nonunions were type I, eight as type II, 12 as type III and six as type IV. The mean follow-up was 51 months (24 to 99). Post-operatively, the patients had a significant decrease in pain (p < 0.001), and a significant improvement in flexion, abduction, external rotation and Constant score (p < 0.001), but not in internal rotation. A total of nine complications were recorded in seven patients: six dislocations, one glenoid loosening in a patient who had previously suffered dislocation, one transitory paresis of the axillary nerve and one infection. Reverse total shoulder replacement may lead to a significant reduction in pain, improvement in function and a high degree of satisfaction. However, the rate of complications, particularly dislocation, was high. Cite this article: Bone Joint J 2014;96-B:1239–43

Currently, the consensus regarding subscapularis tendon repair during a reverse total shoulder arthroplasty (rTSA) is to do so if it is possible. Repair is thought to decrease the risk of dislocation and improve internal rotation but may also increase stiffness and improvement in internal rotation may be of subclinical benefit. Aim is to retrospectively evaluate the outcomes of rTSA, with or without a subscapularis tendon repair. We completed a retrospective review of 51 participants (25 without and 26 with subscapularis repair) who received rTSR by a single-surgeon using a single-implant. Three patient reported outcome measures (PROM) were assessed pre-operatively and post-operative at twelve months, as well as range of movement (ROM) and plain radiographs. Statistical analysis utilized unpaired t tests for parametric variables and Mann-Whitney U test for nonparametric variables. External Rotation ROM pre-operatively was the only variable with a significance difference (p=0.02) with the subscapularis tendon repaired group having a greater range. Pre- and post-operative abduction (p=0.72 & 0.58), forward flexion (p=0.67 & 0.34), ASES (p=0.0.06 & 0.78), Oxford (p=0.0.27 & 0.73) and post-operative external rotation (p=0.17). Greater external rotation ROM pre-operatively may be indicative of the ability to repair the subscapularis tendon intra-operatively. However, repair does not seem to improve clinical outcome at 12 months. There was no difference of the PROMs and AROMs between the subscapularis repaired and not repaired groups for any of the variables at the pre-operative or 12 month post operative with the exception of the external rotation ROM pre-operatively. We can conclude that from PROM or AROM perspective there is no difference if the tendon is repaired or not in a rTSR and indeed the patients without the repair may have improved outcomes at 12 months

Introduction. Reverse total shoulder replacement is performed for the treatment of rotator cuff arthropathy, massive irreparable cuff tears and failed shoulder hemiarthroplasty with irreparable rotator cuff tears. The aim of this study was to assess the clinical and radiological outcome of single surgeon series of Equinoxe® reverse total shoulder replacement at a district general hospital. Materials/Methods. Consecutive patients who underwent Equinoxe® reverse total shoulder replacement at our unit from Jun 2008 to Dec 2010 were retrospectively reviewed. Indications for surgery, complications and radiological outcomes were assessed. Oxford shoulder score was used to assess the functional outcome. Results. Between Jun 2008 and Dec 2012, forty-one reverse total shoulder replacements were performed by the senior author in 37 patients. Of these, Equinoxe® prostheses were used in 27 operations (26 patients). These included 22 female and 4 male patients. Cuff arthropathy was the commonest preoperative diagnosis (23 patients), followed by proximal humeral fracture non-union (2 patients), failed hemiarthroplasty (one patient) and failed resurfacing (one patient). The mean follow up was 10 months (3 to 17 months). At the time of the study, three patients had died due to unrelated causes, two were not contactable and the remaining 21 patients were analysed. The mean oxford shoulder score was 35.8 (21–48). Nineteen patients (90.5%) graded their outcome a good to excellent while 2 patients (9.5%) graded as poor. Seventeen patients (81%) expressed that they would recommend this operation. One patient (4.7%) had infection and another had dislocation. Overall, there were 3 reoperations (14.3%); first washout, second change of humeral tray and third excision of lateral end of clavicle and reattachment of deltoid. Two patients (9.5%) had small glenoid notching. There was no loosening, neurovascular injury or postoperative haematoma. Conclusion. Early outcome of Equinoxe reverse shoulder replacement is promising. Longer follow-up is required to further assess the outcome

Abstract. Background/Objectives. The incidence of reverse total shoulder replacement (rTSR) implantation is increasing globally, but apprehension exists regarding complications and associated challenges. We retrospectively analysed the senior author's series of rTSR from a tertiary centre using the VAIOS shoulder system, a modular 4th generation implant. We hypothesised that the revision rTSR cohort would have less favourable outcomes and more complications. Methods. 114 patients underwent rTSR with the VAIOS system, over 7 years. The primary outcome was implant survival. Secondary outcomes were Oxford shoulder scores (OSS), radiographic analysis (scapular notching, tuberosity osteolysis, and periprosthetic radiolucent lines) and complications. Results. There were 55 Primary rTSR, 31 Revision rTSR and 28 Trauma rTSR. Implant survival: Primary rTSR- 0 revisions, average 3.35-year follow-up. Revision rTSR-1 revision (4.17%), average 3.52-year follow-up. Trauma rTSR- 1 revision (3.57%), average 4.56-year follow-up OSS: Average OSS improved from 15.39 to 33.8 (Primary rTSR) and from 15.11 to 29.1 (Revision rTSR). Average post-operative OSS for the Trauma rTSR was 31.4 Radiological analysis and complications: Low incidence of scapular notching One hairline fracture below the tip of stem, noted incidentally, which required no treatment. One periprosthetic fracture after alcohol related fall. Treated non-surgically One joint infection requiring two-stage revision to rTSR. One dislocation noted at 2 year follow up. This patient had undergone nerve grafting within 6 months of rTSR for axillary nerve injury sustained during the original fracture dislocation. One acromial fracture with tibial and distal humeral fracture after a fall. Conclusions. The 4th generation modular VAIOS implant is a reliable option for various indications. The revision rTSR cohort had favourable outcomes with low complication rates. In this series, early-to-medium term results suggest lower revision rates and good functional outcomes when compared to published reports. We plan to monitor long-term implant survivorship and patient reported outcomes. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Introduction. Reverse total shoulder arthroplasty (RTSA) is rapidly being adopted as the standard procedure for a growing number of shoulder arthropathies. Though short-term outcomes are promising, mid- and long-term follow-ups present a number of complications – among them, humeral stem and glenosphere component loosening. Though not the primary complication, previously reported aseptic loosening required revision in 100% of cases. As the number of patients undergoing RTSA increases, especially in the younger population, it is important for surgeons to identify and utilize prostheses with stable long-term fixation. It has previously been shown in the hip and knee literature that implant migration in the first two years following surgery is predictive of later failure due to loosening in the 5=10-year postoperative window. The purpose of this study is to, for the first time, evaluate the pattern and total magnitude of implant migration in reverse shoulder arthroplasty using the gold standard imaging technique radiostereometric analysis (RSA). Methods. Forty patients were prospectively randomized to receive either a cemented or press-fit humeral stem, and a glenosphere secured to the glenoid with either autologous bone graft or 3D printed porous titanium for primary reverse total shoulder arthroplasty. Following surgery, participants are imaged using RSA, a calibrated, stereo x-ray technique. Radiographs are acquired at 6 weeks (baseline), 3 months, 6 months, 1 year, and 2 years. Migration of the humeral stem and glenosphere at each time point is compared to baseline. Migration of the prostheses is independently compared between humeral stem fixation groups and glenosphere fixation groups using a two-way repeated measures ANOVA with Tukey's test for multiple comparisons. Results. Follow-ups are ongoing and preliminary results are presented. Significant differences were observed at the 6-month and 1-year time points for superior-inferior translation (p = 0.0067, p = 0.0048), and total three-dimensional translation (p = 0.0011, p = 0.0272) between humeral stems, with press-fit humeral stems subsiding significantly more than cemented stems. Migration between the 6-month and 1-year time points was minimal for both stem fixation groups (less than 0.2 mm). No significant differences were observed along any axis at any time point for the glenosphere fixation groups. Conclusion. There is a trend towards increased subsidence with the use of press-fit stems compared to cemented stems in the first six months postoperatively, as is expected. Both implant fixation techniques demonstrate stability from six months through one year, and this trend is expected through two-year follow-up. Similarly, both glenosphere fixation techniques demonstrate immediate and stable fixation through one year

Aims of the study: To assess the results of one-stage revision of infected reverse total shoulder arthroplasty as a new treatment for this major surgical complication. Materials: 11 consecutive patients with infected reverse shoulder prosthesis (DePuy International Ltd, Leeds, UK) were treated with a direct-exchange reverse total shoulder arthroplasty between March 2005 and June 2007. These patients were retrospectively followed. Methods: Via a superior extended deltoideopectoral, clavicular osteotomy approach, according to Redfern-Wallace, a removal of the prosthesis is performed. Multiple operative specimens (4 to 8) are taken and cultured. A thorough synovectomy is performed before implanting a new reverse total shoulder arthroplasty (7 Delta. ®. 3.2 tsp and 4 DeltaXtend. ®. tsp). A gentamycine (Duracol. ®. ) impregnated membrane is interpositioned between baseplate and glenosphere. Immediate postoperative passive and active mobilisation is permitted if no pain is present. Results: Clinical symptoms are seldom severe pain (3) or severe limitation of function (3). A fistula is mainly present (8) without alterating the function. No prosthetic loosening was present at the humeral and glenoid site confirming the absence of radiological infectious signs. All but one patient are considered free of infection at mean follow up of 24 months (12m – 36m) and without antibiotic treatment for minimum 6 months. In only 1 patient the infection persisted necessitating a two-stage revision, unfortunately without definitive cure. Only three early complications are seen (< 2 months: posterior dislocation, postoperative haematoma and clavicle fracture). The mean postoperative Constant-Murley score was 52 (14–81) at latest follow up. Peroperative samples identified Propionbacterium species (5), Coagulase-negative staphylococci (4), MRSA (1) and with E.Coli (1) infection. Monobacterial infection was seen in 6 shoulders, multibacterial in 2 shoulders and in 2 shoulders cultures were negative. Discussion: This cohort of patients has a different syndrome than the known infected anatomical prosthesis. This pathology seems to be rarely associated with severe pain (3) or limitation of function (3). Draining fistulas without alterating the function of the shoulder [CS: mean 43 (3–63)] are more frequently present making a preoperative diagnosis easier and more certain. Recurrence rate of infection is comparable to the classical two-stage revision. Preoperative stiff and painful shoulders seems to have a bad prognosis despite definite cure of the infection. Supple shoulders (mainly associated with a fistula) can be treated with a good functional result. Conclusion: One-stage revision arthroplasty is an attractive alternative treatment for infected reverse total shoulder arthroplasty

The reverse total shoulder replacement (rTSR) has excellent clinical outcomes and prosthesis longevity, and thus, the indications have expanded to a younger age group. The use of a stemless humeral implant has been established in the anatomic TSR; and it is postulated to be safe to use in rTSR, whilst saving humeral bone stock for younger patients. The Lima stemless rTSR is a relatively new implant, with only one paper published on its outcomes. This is a single-surgeon retrospective matched case control study to assess short term outcomes of primary stemless Lima SMR rTSR with 3D planning and Image Derived Instrumentation (IDI), in comparison to a matched case group with a primary stemmed Lima SMR rTSR with 3D planning and IDI. Outcomes assessed: ROM, satisfaction score, PROMs, pain scores; and plain radiographs for loosening, loss of position, notching. Complications will be collated. Patients with at least 1 year of follow-up will be assessed. With comparing the early radiographic and clinical outcomes of the stemless rTSR to a similar patient the standard rTSR, we can assess emerging trends or complications of this new device. 41 pairs of stemless and standard rTSRs have been matched, with 1- and 2-year follow up data. Data is currently being collated. Our hypothesis is that there is no clinical or radiographical difference between the Lima stemless rTSR and the traditional Lima stemmed rTSR

Introduction. Total shoulder arthroplasty is the fastest growing joint replacement in recent years, with projected compound annual growth rates of 10% for 2016 through 2021 – higher than those of both the hip and knee combined. Reverse total shoulder arthroplasty (RTSA) has gained particular interest as a solution for patients with irreparable massive rotator cuff tears and failed conventional shoulder replacement, for whom no satisfactory intervention previously existed. As the number of indications for RTSA continues to grow, so do implant designs, configurations, and fixation techniques. It has previously been shown that continuous implant migration within the first two years postoperatively is predictive of later loosening and failure in the hip and knee, with aseptic loosening of implant components a guaranteed cause for revision in the reverse shoulder. By identifying implants with a tendency to migrate, they can be eliminated from clinical practice prior to widespread use. The purpose of this study is to, for the first time, evaluate the pattern and magnitude of implant component migration in RTSA using the gold standard imaging technique radiostereometric analysis (RSA). Methods. Forty patients were prospectively randomized to receive either a cemented or press-fit humeral stem, and a glenosphere secured to the glenoid with either autologous bone graft or 3D printed porous titanium (Aequalis Ascend Flex, Wright Medical Group, Memphis, TN, USA) for primary reverse total shoulder arthroplasty. Following surgery, partients are imaged using RSA, a calibrated, stereo x-ray technique, at 6 weeks (baseline), 3 months, 6 months, 1 year, and 2 years. Migration of the humeral stem and glenosphere at each time point is compared to baseline. Preliminary results are presented, with 15 patients having reached the 6-month time point by presentation. Results. Implant migration of ten participants at the 3-month time point is presented. Maximum total point motion (MTPM) is a measure of translation and rotation of the point on the implant that has moved the most from baseline. Average MTPM ± SD of the humeral stem is 1.18 ± 0.65 mm and 0.98 ± 0.46 mm for press-fit (n = 6) and cemented (n = 4) stems, respectively; and 0.25 ± 0.09 mm and 0.47 ± 0.24 mm for bone graft (n = 4) and porous titanium (n = 6) glenosphere fixations, respectively, at the 3-month time point. Conclusion. There is a trend towards increased migration with the use of press-fit humeral stems and porous titanium glenosphere fixation, though no conclusions can be made from the current sample size. Further, though differences in migration magnitude may be observed at early postoperative time points, it is expected that all fixation techniques will show stability from 1 to 2 years postoperatively

Modern musculoskeletal modeling techniques have been used to simulate shoulders with reverse total shoulder arthroplasty and study how geometric changes resulting from implant placement affect shoulder muscle moment arms. These studies do not, however, take into account how changes in muscle length will affect the force generating capacity of muscles in their post-operative state. The goal of this study was to develop and calibrate a patient-specific shoulder model for subjects with RTSA in order to predict muscle activation during dynamic activities. Patient-specific muscle parameters were estimated using a nested optimization scheme calibrating the model to isometric arm abduction data at 0°, 45° and 90°. The model was validated by comparing predicted muscle activation for dynamic abduction to experimental electromyography recordings. A twelve-degree of freedom model was used with experimental measurements to create a set of patient-specific data (three-dimensional kinematics, muscle activations, muscle moment arms, joint moments, muscle lengths, muscle velocities, tendon slack lengths, optimal fiber lengths and peak isometric forces) estimating muscle parameters corresponding to each patient's measured strength. The optimization varied muscle parameters to minimize the difference between measured and estimated joint moments and muscle activations for isometric abduction trials. This optimization yields a set of patient-specific muscle parameters corresponding to the subject's own muscle strength that can be used to predict muscle activation and muscle lengths for a range of dynamic activities. The model calibration/optimization procedure was performed on arm abduction data for a subject with reverse total shoulder arthroplasty. Muscle activation predicted by the model ranged between 3% and 90% of maximum. The maximum joint moment produced was 20 Nm. The model replicated measured joint moments accurately (R2 > 0.99). The optimized muscle parameter set produced feasible muscle moments and muscle activations for dynamic arm abduction, when calibrated using data from isometric force trials. Current modeling techniques for the upper extremity focus primarily on geometric changes and their effects on shoulder muscle moment arms. In an effort to create patient-specific models, we have developed a framework to predict subject-specific muscle parameters. These estimated muscle parameters, in combination with patient-specific models that incorporate the patient's joint configurations, kinematics and bone anatomy, provide a framework to predict dynamic muscle activation in novel tasks and, for example, predict how joint center changes with reverse total shoulder arthroplasty may affect muscle function

Glenoid baseplate positioning for reverse total shoulder replacements (rTSR) is key for stability and longevity. 3D planning and image-derived instrumentation (IDI) are techniques for improving implant placement accuracy. This is a single-blinded randomised controlled trial comparing 3D planning with IDI jigs versus 3D planning with conventional instrumentation. Eligible patients were enrolled and had 3D pre-operative planning. They were randomised to either IDI or conventional instrumentation; then underwent their rTSR. 6 weeks post operatively, a CT scan was performed and blinded assessors measured the accuracy of glenoid baseplate position relative to the pre-operative plan. 47 patients were included: 24 with IDI and 23 with conventional instrumentation. The IDI group were more likely to have a guidewire placement within 2mm of the preoperative plan in the superior/inferior plane when compared to the conventional group (p=0.01). The IDI group had a smaller degree of error when the native glenoid retroversion was >10° (p=0.047) when compared to the conventional group. All other parameters (inclination, anterior/posterior plane, glenoids with retroversion <10°) showed no significant difference between the two groups. Both IDI and conventional methods for rTSA placement are very accurate. However, IDI is more accurate for complex glenoid morphology and placement in the superior-inferior plane. Clinically, these two parameters are important and may prevent long term complications of scapular notching or glenoid baseplate loosening. Image-derived instrumentation (IDI) is significantly more accurate in glenoid component placement in the superior/inferior plane compared to conventional instrumentation when using 3D pre-operative planning. Additionally, in complex glenoid morphologies where the native retroversion is >10°, IDI has improved accuracy in glenoid placement compared to conventional instrumentation. IDI is an accurate method for glenoid guidewire and component placement in rTSA

Reverse Total shoulder arthroplasty (RTSA) was initially introduced to treat rotator cuff arthropathy. With proven successful long-term outcomes, it has gained a noteworthy surge in popularity with its indications consequently being extended to treating various traumatic glenohumeral diseases. Several countries holding national registries remain a guide to the use the prosthesis, however a notable lack of epidemiological data still exists. More so in South Africa where the spectrum of joint disease related to communicable diseases such as HIV and tuberculosis may influence indications and patient demographics. By analysing the epidemiology of patients who underwent RTSA at our institution, we aimed to outline the local disease spectrum, the patients afflicted and indications for surgery. A retrospective review of all patients operated within the sports unit between 1 January 2019 and 31 December 2022 was conducted. An analysis of the epidemiological data pertaining to patient demographics, diagnosis, indications for surgery and complications were recorded. Included in the review were 58 patients who underwent primary RTSA over the 4-year period. There were 41 females and 17 male patients, age <55 years (n= 14) >55 years (n=44). The indications included 23 rotator cuff arthropathy (40%), 12 primary glenohumeral osteoarthritis (OA) (20%), 10 avascular necrosis (AVN) humeral head (17%), 7 inflammatory OA (12%), 4 chronic shoulder dislocation (7%) and 2 sequalae of proximal humerus fractures (4%). The study revealed RTSA being performed in patients older than 55 years of age, the main pathologies included rotator cuff arthropathy and primary OA, however AVN and shoulder dislocations secondary to trauma contributed significantly to the total tally of surgeries undertaken. This highlights the disease burden of developing countries contributing to patients presenting for RTSA

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

Backgrounds. The rigid fixation of glenoid base plate is essential for the prevention of dissociation of the construct in the reverse total shoulder arthroplasty. For the rigid fixation, ideal placement of fixation screw is crucial but it is difficult to determine the best direction and length of screws. The purpose of this study was to determine configuration of optimal screw in cadaveric scapulae and compare with that in patient who underwent reverse total shoulder arthroplasty. Materials and methods. Seven scapulae were used and implanted using a variable angle base plate with four directions screws. Optimal screw placement was defined as that which maximized screw length, accomplished far cortical purchase. Insertion angle and length of every screw was measured from AP and axial radiograph taken after the screws fixation. In a similar manner, the insertion angles of screws were measured from radiographs of 7 postoperative patients who underwent reverse total shoulder arthroplasty. The averages of length and insertion angle of 4 screws from two groups were compared. Result. The average lengths of screws were anterior 29.4 mm, posterior 15.0 mm, superior 36.0 mm, inferior 46.7 mm in the cadavers group and 22.2 mm, 22.3 mm, 28.0 mm, 29.1 mm each in the patient group. There was statistical significance of the difference of the insertion angle of superior and inferior screws between two groups. Conclusion. Trajectory angles of superior and inferior screw were smaller than those of optimal screws. Awareness of this tendency is helpful to insert the optimal screws intraoperatively

Introduction. The purpose of this study was to compare implant survivorship and functional outcomes in patients undergoing reverse total shoulder arthroplasty (RTSA) for acute proximal humeral fracture (PHF) with those undergoing elective RTSA in a population-based cohort study. Methods. Prospectively collected data from the New Zealand Joint Registry from 1999 to 2021 and identified 7,277 patients who underwent RTSA. Patients were categorized by pre-operative indication, including acute PHF (10.1%), rotator cuff arthropathy (RCA) (41.9%), osteoarthritis (OA) (32.2%), rheumatoid arthritis (RA) (5.2%) and old traumatic sequelae (4.9%). The PHF group was compared with elective indications based on patient, implant, and operative characteristics, as well as post-operative outcomes (Oxford Shoulder Score [OSS], and revision rate) at 6 months, 5 and 10 years after surgery. Survival and functional outcome analyses were adjusted by age, sex, ASA class and surgeon experience. Results. Implant survivorship at 10 years for RTSA for PHF was 97.3%, compared to 96.1%, 93.7%, 92.8% and 91.3% for OA, RCA, RA and traumatic sequelae, respectively. When compared with RTSA for PHF, the adjusted risk of revision was higher for traumatic sequelae (hazard ratio = 2.29; 95% CI:1.12–4.68, p=0.02) but not for other elective indications. At 6 months post-surgery, OSS were significantly lower for the PHF group compared to RCA, OA and RA groups (31.1±0.5 vs. 35.6±0.22, 37.7±0.25, 36.5±0.6, respectively, p<0.01), but not traumatic sequelae (31.7±0.7, p=0.43). At 5 years, OSS were only significantly lower for PHF compared to OA (37.4±0.9 vs 41.0±0.5, p<0.01), and at 10 years, there were no differences between groups. Discussion and Conclusion. RTSA for PHF demonstrated reliable long-term survivorship and functional outcomes compared to other elective indications. Despite lower functional outcomes in the early post-operative period for the acute PHF group, implant survivorship rates were similar to patients undergoing elective RTSA

Reverse total shoulder arthroplasty (RTSA) has a proven track record as an effective treatment for a variety of rotator cuff deficient conditions. However, glenoid erosion associated with the arthritic component of these conditions can present a challenge for the shoulder arthroplasty surgeon. Options for treatment of glenoid wear include partial reaming with incomplete baseplate seating, bony augmentation using structural or impaction grafting techniques, and augmented baseplates. Augmented components have the advantage of accommodating glenoid deformity with a durable material and also ream less subchondral bone; both of which may offer an advantage over traditional bone grafting. Biomechanical and early clinical studies of augmented glenoid baseplates suggest they are a reasonable treatment option, though posteriorly augmented baseplates have shown better performance than superiorly augmented implants. However, there are no mid- or late-term studies comparing augmented baseplates to bone grafting or partial reaming. We present a live surgical demonstration of RTSA for a patient with advanced glenoid erosion being treated with an augmented glenoid baseplate that can be dialed in the direction of any deformity (superior, posterior, etc.). This versatility allows the surgeon to place the augment in any direction and is not confined to the traditional concepts of glenoid wear in a single vector. Clearly, longer term follow up studies are needed to determine the ultimate effectiveness of these devices in treating glenoid deformity in RTSA

Reverse total shoulder arthroplasty (RSA) with glenoid bone grafting has become a common option for the management of significant glenoid bone loss and deformity associated with glenohumeral osteoarthritis. Despite the increasing utilization of this technique, our understanding of the rates of bone graft union, complications and outcomes are limited. The objectives of this systematic review are to determine 1) the overall rate of bone graft union, 2) the rate of union stratified by graft type and technique, 3) the reoperation and complication rates, and 4) functional outcomes, including range of motion (ROM) and functional outcome scores following RSA with glenoid bone grafting. A comprehensive search of MEDLINE, Embase, and CINAHL databases was completed for studies reporting outcomes following RSA with glenoid bone grafting. Inclusion criteria included clinical studies with greater than 10 patients, and minimum follow up of one year. Studies were screened independently by two reviewers and quality assessment was performed using the MINORs criteria. Pooled and frequency-weighted means and standard deviations were calculated where applicable. Overall, 15 studies were included, including nine retrospective case series (level IV), four retrospective cohort studies (level III), one prospective cohort study (level II) and one randomized control trial (level I). The entire cohort consisted of 555 patients with a mean age of 71.9±2.1 years and 70 percent female. The mean follow-up was 33.8±9.4 months. Across all procedures, 84.9% (N=471) were primary arthroplasties, and 15.1% (N=84) were revisions. The overall graft union rate was 89.2%, but was higher at 96.1% among studies that used autograft bone (9 studies, N=308). When stratified by technique, bone graft for the purposes of lateralization resulted in a 100% union rate (4 studies, N=139), while eccentric bone grafts used in asymmetric bone loss resulted in a lower union rate of 84.9% (10 studies, N=345). The overall revision rate was 6.5%, and was lowest following primary cases at 1.8% (11 studies, N=393). The pooled mean scapular notching rate was 20.1% (12 studies, N=497). Excluding notching, the pooled mean complication rate was 21.5% for all cases and 13% for primary cases (11 studies, N=393). When reported, there was significant improvement in post-operative ROM in all planes. There was also improvement in functional outcome scores, whereby the frequency-weighted mean Constant score increased from 25.9 to 67.2 (8 studies, N=319), ASES score increased from 34.7 to 75.2 (4 studies, N=142), and SST score increased from 2.1 to 7.6 (5 studies, N=196) at final follow up. This review demonstrates that glenoid bone grafting with RSA results in good mid-term clinical and radiographic outcomes. Union rate appears to depend highly on graft type and technique, whereby the highest union rates were seen following the use of autograft bone for the purposes of lateralization. Interestingly, the union rate of autograft bone for the purposes of augmentation in eccentric bone loss is considerably lower and its impact on the long-term survivorship of the implant remains unknown

We present a series of 18 consecutive cases of primary reverse total shoulder arthroplasty for irreparable proximal humerus fractures in patients over 70. Failure of tuberosity union and poor cuff function leads to unsatisfactory results in over half the patients with hemiarthroplasty. Reverse total shoulder arthroplasty does not depend upon a functional rotator cuff and requires little formal rehabilitation. Patients over 70 with irreparable proximal humerus fractures treated with a reverse total shoulder arthroplasty were included in this study. Only primary arthroplasties were included. Reverse arthroplasties for failed hemiarthroplasties were excluded. All arthroplasties were performed using either a deltoid split direct lateral (superior) approach or the antero-lateral MacKenzie approach. The SMR reverse total shoulder prothesis was implanted in all cases using a press-fit glenoid base plate and glenosphere, and press-fit or cemented humerus stem. Tuberosity repair was attempted in 10 cases. The supraspinatus was excised from the greater tuberosity. Patients were allowed self-mobilisation after two weeks in a sling. Patients were recruited and followed up per ethics approved protocol. Outcome measures used were range of motion, dislocation and revision rates radiological signs of loosening and glenoid notching, DASH and Constant scores. Results were compared to another series of cases of reverse shoulder arthroplasty for sequelae of trauma and failed hemiarthroplasties, as well as a series of primary hemiarthroplasties. At an average follow-up of 30 months (minimum 12 months) all patients were satisfied with their results. Average forward elevation was 132 deg. and abduction 108 deg. There was not deterioration of movement at 12 or 24 months. No patient had ongoing pain. The average constant score was 62. There was no evidence of humeral stem loosening apart from one case of early subsidence in a press fit stem. Eleven cases showed glenoid notching, four Nerot grade 1, six Nerot grade 2 and one Nerot grade 3. All notching had stabilised after 12 months. There were no cases of dislocation. No case needed revision, or awaits revision. All cases were pain-free at last review. Overall results for this group of primary reverse arthroplasties for fractures was much better than for reverse arthroplasties for sequelae of trauma. The results were also better than for primary hemiarthroplasties. Irreparable three and four part fractures of the proximal humerus pose management challenges in the elderly. The reverse total shoulder arthroplasty is very attractive option for elderly patients with irreparable proximal humerus fractures. They require little rehabilitation and can give reproducibly good functional results, which do not deteriorate with time

Most common current surgical treatment options for cuff tear arthropathy (CTA) are hemiarthroplasty and reverse total shoulder replacement. At our unit we have been using Reverse Total shoulder replacement (TSR) for CTA patients since 2001. We present our results of Reverse TSR in 64 patients (single surgeon) with a mean follow up of 2 years (Range 1 to 8 years). There were 45 males and 19 females in the study with a mean age of 70 years. Preoperative and postoperative Constant scores were collected by a team of specialist shoulder physiotherapists. Preoperatively plain radiographs were used to evaluate the severity of arthritis and bone stock availability. 90% patients showed an improvement in the Constant score post operatively. The mean improvement in Constant score was 25 points. The mean Pain Score (max 15) improved from 6.3 to 11.8; the mean ADL Score (max 20) improved from 6.8 to 12.3; the mean Range of Motion score (max 40) improved from 10.8 to 20.2; but the mean Power Score (max 25) only improved from 0.9 to 4.9. The differences in improvement were statistically significant in each category. A total 6 patients (10%) required 10 revision surgeries for various reasons. Two patients dislocated anteriorly who were treated by open reduction. Two patients required revision of the glenoid component due to loosening after a mean of 2 years. One patient required revision of the humeral component with strut grafting secondary to severe osteolysis. Only one patient required revision of both humeral and glenoid components secondary to malpositioning. Three patients died for reasons unconnected with their shoulder problems and surgery. Radiographic analysis at the latest follow up (mean 24 months) showed inferior glenoid notching in 40% cases. Heterotrophic ossification was not seen in our series. We conclude that reverse TSR is a viable option for treatment of cuff tear arthropathy however glenoid loosening and scapular notching remains an issue

Aims. The reasons for failure of a hemirthroplasty (HA) when used to treat a proximal humeral fracture include displaced or necrotic tuberosities, insufficient metaphyseal bone-stock, and rotator cuff tears. Reverse total shoulder arthroplasty (rTSA) is often the only remaining form of treatment in these patients. The aim of this study was to evaluate the clinical outcome after conversions from a failed HA to rTSA. Material and Methods. A total of 35 patients, in whom a HA, as treatment for a fracture of the proximal humerus, had failed, underwent conversion to a rTSA. A total of 28 were available for follow-up at a mean of 61 months (37 to 91), having been initially reviewed at a mean of 20 months (12 to 36) postoperatively. Having a convertible design, the humeral stem could be preserved in nine patients. The stem was removed in the other 19 patients and a conventional rTSA was implanted. At final follow-up, patients were assessed using the American Shoulder and Elbow Surgeons (ASES) score, the Constant Score, and plain radiographs. Results. At final follow-up, the mean ASES was 59 (25 to 97) and the mean adjusted Constant Score was 63% (23% to 109%). Both improved significantly (p < 0.001). The mean forward flexion was 104° (50° to 155°) and mean abduction was 98° (60° to 140°). Nine patients (32%) had a complication; two had an infection and instability, respectively; three had a scapular fracture; and one patient each had delayed wound healing and symptomatic loosening. If implants could be converted to a rTSA without removal of the stem, the operating time was shorter (82 minutes versus 102 minutes; p = 0.018). Conclusion. After failure of a HA in the treatment of a proximal humeral fracture, conversion to a rTSA may achieve pain relief and improved shoulder function. The complication rate is considerable. Cite this article: Bone Joint J 2018;100-B:761–6

Aims. To date, there is insufficient evidence available to compare the outcome of cemented and uncemented fixation of the humeral stem in reverse shoulder arthroplasty (RSA). . Methods. A systemic review comprising 41 clinical studies was performed to compare the functional outcome and rate of complications of cemented and uncemented stems in RSA. These included 1455 cemented and 329 uncemented shoulders. The clinical characteristics of the two groups were similar. Variables were compared using pooled frequency-weighted means and relative risk ratios (RR). Results. Uncemented stems had a significantly higher incidence of early humeral stem migration (p < 0.001, RR 18.1, 95% confidence interval (CI) 5.0 to 65.2) and non-progressive radiolucent lines (p < 0.001, RR 2.4, 95% CI 1.7 to 3.4), but a significantly lower incidence of post-operative fractures of the acromion compared with cemented stems (p = 0.004, RR 14.3, 95% CI 0.9 to 232.8). There was no difference in the risk of stem loosening or revision between the groups. The cemented stems had a greater relative risk of infection (RR 3.3, 95% CI 0.8 to 13.7), nerve injury (RR 5.7, 95% CI 0.7 to 41.5) and thromboembolism (RR 3.9, 95% CI 0.2 to 66.6). The functional outcome and range of movement were equivalent in the two groups. . Discussion. RSA performed with an uncemented stem gives them equivalent functional outcome and a better complication profile than with a cemented stem. The natural history and clinical relevance of early stem migration and radiolucent lines found with uncemented stems requires further long-term study. Take home message: This study demonstrates that uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems when used for reverse total shoulder arthroplasty. . Cite this article: Bone Joint J 2016;98-B:65–74

Surgeries for reverse total shoulder arthroplasty (RTSA) significantly increased in the last ten years. Initially developed to treat patients with cuff tear arthropathy (CTA) and pseudoparalysis, wider indications for RTSA were described, especially complex proximal humerus fractures. We previously demonstrated in patients with CTA a different sequence of muscular activation than in normal shoulder, with a decrease in deltoid activation, a significant increase of upper trapezius activation and slight utility of the latissimus dorsi. There is no biomechanical study describing the muscular activity in patients with RTSA for fractures. The aim of this work is to describe the in vivo action of RTSA in patients with complex fractures of the proximal humerus. We conducted an observational prospective cohort study comparing 9 patients with RTSA for complex humerus fracture (surgery more than 6 months, healed tuberosities and rehabilitation process achieved) and 10 controls with normal shoulder function. Assessment consisted in a synchronized analysis of range of motion (ROM) and muscular activity on electromyography (EMG) with the use of 7 bipolar cutaneous electrodes, 38 reflective markers and 8 motion-recording cameras. Electromyographic results were standardized and presented in muscular activity (RMS) adjusted with maximal isometric contractions according to the direction tested. Five basic movements were evaluated (flexion, abduction, neutral external rotation, external rotation in 90° of abduction and internal rotation in 90° of abduction). Student t-test were used for comparative descriptive analysis (p < 0,05). The overall range of motion with RTSA is very good, but lower than the control group: flexion 155.6 ± 10 vs 172.2 ± 13.9, p<0.05, external rotation at 90° 55.6 ± 25 vs 85.6 ± 8.8, p<0,05, internal rotation at 90° 37.8 ± 15.6 vs 52.2 ± 12, p<0,05. The three heads of the deltoid are more stressed during flexion and abduction in the RTSA group (p. The increased use of the 3 deltoid chiefs does not support the hypothesis proposed by Grammont when the RTSA is performed for a complex proximal humerus fracture. This can be explained by the reduced dispalcement of the rotation center of the shoulder in these patients compared to those with CTA. These patients also didn't present shoulder stiffness before the fracture. The maximal muscle activity of the trapezius in flexion and of the latissimus dorsi in flexion and abduction had not been described to date. These new findings will help develop better targeted rehabilitation programs. In addition, the significant role of the latissimus dorsi must question the risks of its transfer (L'Episcopo procedure) to compensate for external rotation deficits

Background. Stress fracture of the acromium and scapular spine is a common complication following reverse total shoulder arthroplasty (RSA), with a reported incidence of 3.1%–11%. There is some evidence associating osteoporosis with increased risk of acromial stress fractures, but little else is known about the causes of acromial stress fractures after RSA. This study aims to define better preoperative factors, including demographics, comorbidities, and diagnoses, which predispose patients to postoperative acromial stress fractures. Methods. We retrospectively identified patients who underwent primary or revision RSA for any indication between January 2013 and December 2018 by two surgeons at two separate hospitals. Stress fractures of the acromion were identified on plain radiographs or computed tomography, when necessary. Patient demographics, comorbidities, and surgical indications were compared between patients with and without acromial stress fractures. Results. A total of 1,488 arthroplasties were identified and met the inclusion criteria. Of the study sample, 54 patients were diagnosed with a postoperative acromial stress fracture, an incidence of 3.6%. Patients in the stress fracture cohort were significantly more likely to have preoperative rotator cuff pathology (p<0.001), be of female gender (p<0.001), older (p=0.002), and osteoporotic (p<0.001; Table I). Thyroid disease (p=0.045) and inflammatory or rheumatoid arthritis (p=0.02) were also more frequent among patients with acromial stress fractures (Table I). No other comorbidities, including obesity (p=0.21) and diabetes (p=0.58), correlated significantly with postoperative acromial stress fracture (Table I). Conclusions. Old age, female gender, diagnosed osteoporosis, inflammatory arthritis, thyroid disease, and preoperative rotator cuff deficiency may all be risk factors for postoperative acromial stress fractures. Given that rotator cuff pathology is among the predominant indications for RSA, further research is required to determine the etiology and biomechanical basis for acromial stress fractures. For any figures or tables, please contact the authors directly

Musculoskeletal modeling techniques simulate reverse total shoulder arthroplasty (RTSA) shoulders and how implant placement affects muscle moment arms. Yet, studies have not taken into account how muscle-length changes affect force-generating capacity postoperatively. We develop a patient-specific model for RTSA patients to predict muscle activation. Patient-specific muscle parameters were estimated using an optimization scheme calibrating the model to isometric arm abduction data at 0°, 45°, and 90°. We compared predicted muscle activation to experimental electromyography recordings. A twelve-degree of freedom model with experimental measurements created patient-specific data estimating muscle parameters corresponding to strength. Optimization minimized the difference between measured and estimated joint moments and muscle activations, yielding parameters corresponding to subjects' strength that can predict muscle activation and lengths. Model calibration was performed on RTSA patients' arm abduction data. Predicted muscle activation ranged between 3% and 70% of maximum. The maximum joint moment produced was 10 Nm. The model replicated measured moments accurately (R. 2. > 0.99). The optimized muscle parameters produced feasible muscle moments and activations for dynamic arm abduction when using data from isometric force trials. A normalized correlation was found between predicted and experimental muscle activation for dynamic abduction (r > 0.9); the moment generation to lift the arm was tracked (R. 2. = 0.99). Statement of Clinical Significance: We developed a framework to predict patient-specific muscle parameters. Combined with patient-specific models incorporating joint configurations, kinematics, and bone anatomy, they can predict muscle activation in novel tasks and, e.g., predict how RTSA implant and surgical decisions may affect muscle function

Introduction. This paper describes the kinetic and electromyographic contribution of principal muscles around the shoulder of a cohort of patients with reverse total shoulder arthroplasty (RTSA). Surgeries for RTSA significantly increased in the last five years. Initially developed to treat patients with cuff tear arthropathy and pseudoparalysis, wider indications for RTSA were described (massive non repairable rotator cuff tears, complex 4-parts fractures). Since Grammont's theory in 1985, the precise biomechanics of the RTSA has not yet been demonstrated in vivo. Clinical results of patients with RSTA are still unpredictable and vary one from another. Methods. We conducted an observational prospective cohort study comparing 9 patients with RTSA (surgery more than 6 months and rehabilitation process achieved) and 8 controls with normal shoulder function adjusted for age, sex and dominance. Assessment consisted in a synchronized analysis of range of motion (ROM) and muscular activity on electromyography (EMG) with the use of 7 bipolar cutaneous electrodes, 38 reflective markers and 8 motion-recording cameras. Electromyographic results were standardized and presented in muscular activity (RMS) adjusted with maximal isometric contractions according to the direction tested. Five basic movements were evaluated (flexion, abduction, neutral external rotation, external rotation in 90° of abduction and internal rotation in 90° of abduction). Student t-test were used for comparative descriptive analysis (p<0,05). Results. ROM is limited in the RSTA group (flexion 128,5 vs 152,6, p=0,04; abduction 150 vs 166, p=0,02; neutral ext rot 28.3 vs 75.6, p<0,01; 90° ext rot 26,43 vs 70,63, p<0,01, int rot 27.5 vs 49.4, p=0,01). Anterior and middle deltoid shows less muscular activation in RTSA than in controls, sustaining the deltoid potentiation described by Grammont. Posterior deltoid shows decreased activity in external rotation movements in RTSA. Upper trapezius is the main activator in all directions with an early and constant activity in RTSA (p<0,01). Latissimus dorsi demonstrates increased muscular activity in internal rotation with RTSA (p<0,01). Discussion. The sequence of muscular activation in RTSA is different than in normal shoulder. Grammont's theory is confirmed with this study. The significant contribution of both the trapezius and latissimus dorsi has never been described until today. New rehabilitation protocols targeted on those muscle groups could demonstrate better and more homogenous clinical results

Patients over 70 years old have subclinical or impending rotator cuff dysfunction, raising concern about TSA in this population. The purpose of this study is to examine whether reverse total shoulder arthroplasty (RTSA) should be considered for the treatment of glenohumeral osteoarthritis in the presence of an intact rotator cuff (GHOA+IRC in patients older than 70 years of age. Twenty-five elderly (>70 years) patients at least one year status-post RTSA for GHOA+IRC were matched via age, sex, body mass index, smoking status, and whether the procedure involved the dominant extremity with 25 GHOA+IRC patients who received anatomic total shoulder arthroplasty (TSA). Standardised outcome measures, range of motion, and treatment costs were compared between the two groups. Treatment cost was assessed using implant and physical therapy costs as well as reimbursement. Patients who received RTSA for GHO+IRC had significantly lower pre-operative active forward elevation (AFE, 69° vs. 98°, p <0.001) and experienced a greater change in AFE (p=0.01), but had equivalent AFE at final follow-up (140° vs. 142°, p=0.71). Outcomes were otherwise equivalent between groups with no differences. In both those patients who underwent TSA and those that underwent RTSA, significant improvements between pre-operative and final follow-up were seen in all standardised outcome measures and in AFE (p<0.001 in all cases). RTSA provided these outcomes at a cost savings of $2,025 in Medicare reimbursement due to decreased physical therapy costs. In patients over the age of 70 with GHOA+IRC, RTSA provides similar improvement in clinical outcomes to TSA at a reduced cost while avoiding issues related to the potential for subclinical or impending rotator cuff dysfunction

Reverse total shoulder arthroplasty (TSA) has demonstrated success in restoring active elevation for patients with rotator cuff dysfunction (with or without arthritis). However, recovery of active external rotation after reverse TSA has demonstrated variable success. Transfer of the latissimus dorsi has shown promise in restoring active external rotation in those patients with profound external rotation deficits. The combined latissimus transfer and reverse TSA procedure is intra-operatively challenging and fraught with post-operative complications. Technical details and precise indications are necessary to produce the best chance of success with this operation

Traditionally, open reduction and internal fixation (ORIF) and hemiarthroplasty (HA) have been the surgical treatments of choice for displaced proximal humerus fractures (PHF) despite high rates of fixation failure and tuberosity nonunion, especially in the elderly population with poor bone quality. Recently, there has been a significant increase in the use of reverse total shoulder arthroplasty (RTSA) as a treatment option in both acute fractures, as well as a salvage procedure for fracture sequelae (i.e., malunion, nonunion, fixation failure, tuberosity non-union). Despite the growing enthusiasm it remains unknown whether functional outcomes after RTSA as a salvage procedure are similar to those following acute RTSA. As a result, the purpose of this systematic review was to compare functional outcomes after RTSA as a primary versus salvage procedure for displaced PHF in the elderly. A literature search of the electronic databases EMBASE, MEDLINE, and PubMed was conducted to identify all studies comparing RTSA as a primary treatment for displaced PHF and as a salvage procedure for failed initial management. Only studies with a minimum follow-up of two years were included. Data pertaining to range of motion, patient reported outcome measures and complications were extracted from eligible studies and entered into a meta-analysis software package (RevMan version 5.1, The Cochrane Collaboration) for pooled analysis. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of eligible studies. The search identified four studies consisting of 200 patients with a mean age of 73.3 years and a mean follow-up of 3.2 years. There were a total of 76 patients (75% female) who underwent acute RTSA following displaced PHF, while 124 patients (77% female) required salvage RTSA for failure of initial treatment. Primary RTSA was found to have significantly higher American Shoulder and Elbow (ASES) (P = 0.04), Constant (P = 0.01) and University of California at Los Angeles (UCLA) (P = 0.0004) scores compared to salvage RTSA. Forward flexion (P = 0.001) and external rotation (P< 0.0001) were significantly greater amongst those undergoing RTSA acutely versus as a salvage procedure. The odds of having a complication (e.g., infection, dislocation, fracture) were 76% lower amongst those who had primary RTSA compared to salvage RTSA (P = 0.02). The overall quality of eligible studies was moderate to high. Based on the current available evidence, elderly patients with displaced PHF have significantly greater range of motion, higher patient reported outcomes and lower risk of complications with primary RTSA compared to those undergoing RTSA as a salvage procedure. Additional prospective studies are warranted to confirm these findings

Utilization of reverse total shoulder arthroplasty (RTSA) has steadily increased since its 2003 introduction in the American market. Although RTSA was originally indicated for elderly, low demand patients, it is now being increasingly used to treat rotator cuff arthropathy, humeral fractures, neoplasms and failed total and hemi shoulder arthroplasty. There is, therefore, a growing interest in bearing surface wear of RTSA polyethylene humeral liners. In the current study, we examined humeral liners retrieved as part of an IRB approved study to determine the amount of bearing surface wear. We hypothesized that wear of the bearing surface by intentional contact with the glenosphere (mode I) would be minor compared to that produced by scapular notching and impingement of the humeral liner (mode II). Twenty-three retrieved humeral liners were retrieved at revision surgery after an average of 1.5 years implantation time. The average age at implantation was 68 years (range 50–85). Shoulders were revised for loosening (7), instability (6), infection (6), pain (2), and other/unknown reasons (2). The liners were scanned using microCT at a resolution of 50 µm and then registered against unworn surfaces to estimate the bearing surface wear depth. The depth of surface penetration due to impingement of the liner with surrounding structures was measured and the location of the deepest penetration was noted. Mode I wear of the bearing surface was detectable for five of the retrieved liners. The penetration depth was 100 µm or less for four of the liners and approximately 250 microns for the fifth liner. It was noted that the liners with discernable mode I wear were those with longer implantation times (average 2.4 years). Material loss and abrasion of the rim due to mode II wear was noted with measurable penetration in 18 of the liners. Mode II wear penetrated to the bearing surface in 11 liners. It was generally noted that volumetric material loss was dominated by mode II wear (Figure 1). In this study of short to medium term retrieved RTSA humeral liners, mode I wear of the bearing surface was a minor source of material loss. Mode II wear due to scapular notching or impingement of the rim was the dominant source of volumetric wear. This is in agreement with a previous study that we have performed on a smaller cohort of seven liners. It is noteworthy that we were able to detect measurable mode I wear for liners with moderate implantation times. The quantity of bearing surface wear that will be seen in long term retrievals remains unknown at this time

A reverse total shoulder arthroplasty (RSA) is frequently performed in the revision setting. The purpose of this study was to report the clinical outcomes and complication rates following revision RSA (RRSA) stratified according to the primary shoulder procedure undergoing revision, including failed hemiarthroplasty (HA), anatomic total shoulder arthroplasty (TSA), RSA, soft tissue repair (i.e., rotator cuff repair), and open reduction internal fixation (ORIF). A systematic review of the literature was performed using four databases (EMBASE, Medline, SportDISCUS, and Cochrane Controlled Trials Register) between January 1985 and September 2017. The primary outcomes of interest included active range-of-motion (ROM), pain, and functional outcome measures including the American Shoulder and Elbow Surgeons Score (ASES), Simple Shoulder Test (SST), and Constant-Murley (CS) Score. Secondary outcomes included complication rates, such as infection, dislocation, perioperative fracture, base plate failure, neurovascular injury, soft tissue injury, and radiological evidence of scapular notching. Clinical outcome data was assessed for differences between preoperative and postoperative results and complication results were reported as pooled complication rates. Forty-five studies met the inclusion criteria for analysis, which included 1,016 shoulder arthroplasties with a mean follow-up of 45.2 months (range, 31.1 to 57.2 months) (Fig. 1). The mean patient age at revision was 60.2 years (range, 36 to 65.2 years). Overall, RSA as a revision procedure for failed HA revealed favorable outcomes with respect to forward elevation (FE), CS pain, ASES, SST, and CS outcome assessment scores, with mean improvements of 52.5° ± 21.8° (P = < 0 .001), 6.41 ± 4.01 SD (P = 0.031), 20.1 ± 21.5 (P = 0.02), 5.2 ± 8.7 (P = 0.008), and 30.7 ± 9.4 (P = < 0 .001), respectively. RSA performed as a revision procedure for failed TSA demonstrated an improvement in the CS outcome score (33.8 ± 12.4, P = 0.016). RSA performed as a revision procedure for failed soft tissue repair demonstrated significant improvements in FE (60.2° ± 21.2°, P = 0.031) and external rotation (20.8° ± 18°, P = 0.016), respectively. Lastly, RSA performed as a revision procedure for failed ORIF revealed favorable outcomes in FE (61° ± 20.2°, P = 0.031). There were no significant differences noted in RSA performed as a revision procedure for failed RSA, or when performed for a failed TSA, soft tissue repair, and ORIF in any other outcome of interest. Pooled complication rates were found to be highest in failed RSA (10.9%), followed by soft tissue repair (7.1%), HA (6.8%), TSA (5.4%) and ORIF (4.7%). When compared to other revision indications, RRSA for failed HA demonstrated the most favorable outcomes, with significant improvements in ROM, pain, and in several outcome assessments. Complication rates were determined and stratified as per the index procedure undergoing RRSA, patients undergoing revision of a failed RSA were found to have the highest complication rates. With this additional information, orthopaedic surgeons will be better equipped to provide preoperative education regarding the risks, benefits and complication rates to those patients undergoing a RRSA. For any figures or tables, please contact authors directly

Introduction. Proper positioning of the baseplate and optimal screw placement are necessary to avoid loosening or failure of the glenoid component in RTSA. Several in vitro and anatomic studies have documented ideal number, size, length and angulation of baseplate screws. However, such fixation can often be tenuous, as the anatomy of scapula bone varies. Furthermore, it can be difficult to identify regions with the best bone stock intraoperatively even though surgeons have an understanding of scapular anatomy with potential screw trajectories in mind. This often leads to variable screw lengths and angulations in the clinical setting. The purpose of this study was to measure optimal screw lengths and angles to reach ideal regions in cadaveric scapulae and to compare the clinical experiences of three surgeons with each other and against a cadaveric model with screw lengths and angulations. Materials and Methods. Seven cadaveric scapulae were used as the template for optimal screw angulation and length for baseplate implantation. Total 21 cases (seven cases of each 3 surgeons) of reverse total shoulder arthroplasty using the Aequalis®-Reversed shoulder prosthesis (Tornier, France) were included. Measurement of screw angulation was done on the AP and axillary views to account for the superior-inferior and the antero-posterior angulations, respectively. The screw lengths used on each scapula was recorded prior to insertion in cadavers and retrieved from the operative records in clinical cases. Screws directed anteriorly and superiorly were recorded as positive values while posteriorly and inferiorly directed screws were designated negative values. The significant differences in degrees of screw angulation and screw lengths among the 3 surgeon groups were calculated using the ANOVA, with the p value at 0.05. The Mann-Whitney U test was performed to evaluate the cadaver group against the surgeon groups. Results. In cadaveric specimens, the averages of the screw lengths used were 29.4 mm (anterior screw), 15.4 mm (posterior screw), 36.0 mm (superior screw), and 46.70 mm (inferior screw). The anterior screw was directed 6.9° inferior and 7.5° degrees posterior in reference to the central peg. The posterior screw direction was inferior (−5.0°) and posterior (−1.7°); Superior screw was directed superiorly (30.1°) and anteriorly (22.2°), while the inferior screw was aimed inferiorly (−15.3°) and posteriorly (−8.3°). In clinical cases, the differences in screw length among the 3 surgeon groups were not statistically significant. There was no significant difference in screw angulation among the 3 surgeons except posterior screw. Comparing cadaveric specimens from the clinical cases, the anterior screws were shorter and directed more superiorly and anteriorly in the patients, and the superior and inferior screws were directed less superiorly and inferiorly in the patient. Conclusion. We concluded that more vertical screw placement of the superior and inferior screws is necessary to obtain the ideal baseplate fixation

Failure of reverse total shoulder arthroplasty (rTSA) due to loosening of the metaglene remains a concern. The metaglene is typically affixed to the glenoid via four peripheral bone screws, and the orientations of these screws can affect the stability of the metaglene. The purpose of this finite element analysis (FEA) study was to investigate whether screw orientations should be considered on a patient-specific basis to maximise early fixation. Three-dimensional geometries of four scapula specimens were obtained by segmenting from CT data in 3D Slicer. A metaglene and four rigidly attached 4.5 mm diameter, 18 mm long cylinders representing screws, were placed on each reamed glenoid. Each screw was placed at one of four orientations, 15° or 7.5° toward or away from the central axis of the metaglene face, while all others were held in the baseline (BL) configuration, where all screws were perpendicular to the metaglene face. Finite element models were created by meshing with linear tetrahedral elements. Material properties of titanium (E=113.8 GPa, v=0.34) were applied to the metaglene and screws. Cortical bone material properties were considered uniform (E=17.5 GPa, ν=0.3) while cancellous bone material properties were non-uniform and mapped on an element-by-element basis using CT attenuation data. The scapula was fully constrained, and a 252 N superiorly oriented shear force was applied to the inferior portion of the metaglene. Contact was modelled at bone-implant and bone-screw interfaces. Displacements of the metaglene with respect to the glenoid were measured. The orientations of each screw that minimised in-plane displacement were used for specimen-specific (SS) configurations. A global (GL) configuration was also defined based on the averages of SS orientations. FE model-predicted metaglene displacements of the SS, GL, and BL screw configurations were compared using paired t-tests. The average in-plane metaglene displacements for the SS, GL, and BL configurations were 4.8 ± 1.2, 6.5 ± 3.7, and 5.3 ± 1.5 um, respectively. SS configurations significantly decreased displacements by −0.4 ± 0.3 um (−8.5%, p = 0.024) when compared to BL, but the difference of −1.6 ± 3.1 um (25.3%, p = 0.187) was not significant when compared to the GL configuration. In general, the SS configurations resulted in smaller metaglene displacements than the GL configurations, however the difference was not statistically significant. In one specimen, the GL configuration resulted in abnormally large displacements. These results indicate that, while on average, patient-specific orientations won't yield significantly greater fixation than global configurations; non-patient-specific configurations can, in some cases, yield poor results. Therefore, to ensure optimal fixation for all patients, screw orientations should be considered on a patient-specific basis

Introduction. While shoulder elevation can be reliably restored following reverse total shoulder arthroplasty (RTSA), patients may experience a loss of internal and external rotation. Several recent studies have investigated scapular notching and have made suggestions regarding glenosphere placement in order to minimize its occurrence. However, very few studies have looked at how changes in glenosphere placement in RTSA affect internal and external rotation. The purpose of this study was to determine the effect of glenosphere position on internal and external rotation range of motion at various degrees of scaption following RTSA. We hypothesized that alteration in glenosphere position will affect the amount of impingement-free internal and external rotation. Methods. CT scans of the scapula and humerus were obtained from seven cadaver specimens and 3-Dimensional (3D) reconstructions were created. A corresponding 3D RTSA model was created by laser scanning the baseplate, glenosphere, humeral stem and bearing. The RTSA models were then virtually implanted into each specimen. The glenosphere position was determined in relation to the neutral position in 6 different settings: Medialization (5 mm), lateralization (10 mm), superior translation (6mm), inferior translation (6 mm), superior tilt (20°), and inferior tilt (15° and 30°). The humerus in each virtual model was allowed to freely rotate at a fixed scaption angle until encountering bone-bone or bone-implant impingement (180 degrees of limitation). Each model was tested at 0, 20, 40, and 60 degrees of scaption and the impingement-free internal and external rotation range of motion for each scaption angle was recorded. Results. At 0Ëš scaption, only inferior translation, lateralization, and inferior tilt allowed any impingement-free motion in IR and ER. At mid ranges of scaption (20Ëš and 40Ëš) a predictable pattern was seen in which increased lateralization and inferior translation resulted in improved rotation. Supraphysiologic motion (>90Ëš rotation) was seen consistently at 60Ëš of scaption in internal rotation. Both superior and inferior tilt positions resulted in increased ROM in the mid-range of scaption. Acromial impingement was seen when the glenosphere was medialized, superiorly translated and with a superior tilt. Superior translation (6 mm) resulted in no rotation at 0 and 20 degrees of scaption (both IR and ER). Figure 1 and 2: Represents the amount of internal (fig. 1) and external rotation (fig. 2) range of motion measured to bony impingement. 180 degrees was set as the physiologic limit for all measurements. Conclusion. Glenosphere position significantly affected humeral internal and external rotation after Reverse Total Shoulder Arthroplasty in our computer model. Inferior translation (6 mm) or lateralization (10 mm) appears to have the most beneficial effects to internal and external rotation of the shoulder. Inferior tilt (15° and 30°) of the glenosphere also improved overall arc of motion in IR and ER when compared to superior tilt and neutral positions. Superior translation (6 mm) and medialization (5 mm) of the glenosphere caused marked limitations in internal and external rotation due to scapular notching and acromial impingement

Reverse total shoulder arthroplasty (RTSA) provides a surgical alternative to conventional shoulder arthroplasty in the rotator cuff deficient shoulder. Short term data has shown consistent improvements in pain and function but higher complication and failure rates have also been reported. The aims of this study were to identify the early and late complications of RTSA, to establish the frequency of glenoid notching, and to assess the post-operative functional outcomes. 21 patients (22 joints) treated with RTSA at Glasgow Royal Infirmary (GRI) between April 2006 and October 2010 were retrospectively reviewed. Indications for surgery included cuff tear arthropathy, revision hemiarthroplasty and fracture malunion. Complication rates were obtained by analysis of follow up data from Bluespier and case notes. Glenoid notching was graded from x-rays by multiple observers using the Sirveaux classification. Outcome was assessed using the Oxford Shoulder Score (OSS) and range of motion (ROM). The complication rate associated with RTSA was 14.3%, effecting 3 patients. One dislocation and 1 ulnar nerve palsy occurred within 30 days post-op. A late complication was represented by 1 dislocation, which required revision. Glenoid notching occurred in 71.4% (15 of 21patients), though the majority had a low Sirveaux classification (grade 1 or 2). OSS increased post-operatively and showed a linear improvement with time (R. 2. = 0.81) and ROM increased significantly post-op compared with pre-op (p<0.001). The complication rate associated with RTSA at GRI was lower than that reported in literature and the outcome was good as defined by ROM and OSS. The rate of glenoid notching was higher than literature reports but the significance of this is unclear as notching may not be associated with loosening

Introduction. Reverse total shoulder arthroplasty (RTSA) is a semi-constrained joint replacement with an articulating cobalt-chromium glenosphere and ultra-high molecular weight polyethylene (PE). Because of its limited load bearing, surgeons and implant manufacturers have not elicited the use of highly cross-linked PE in the shoulder, and to date have not considered excessive PE wear in the reverse shoulder a primary concern. As the number of shoulder procedures is expected to grow exponentially in the next decade, however, it is important to evaluate how new designs and bearing materials interact and to have an understanding of what is normal in well-functioning joint replacements. Currently, no in vivo investigation into RTSA PE wear has been conducted, with limited retrieval and simulation studies. In vitro and in silico studies demonstrate a large range in expected wear rates, from 14.3 mm. 3. /million cycles (MC) to 126 mm. 3. /MC, with no obvious relationship between wear rate and polyethylene diameter. The purpose of this study is to evaluate, for the first time, both volumetric and linear wear rates in reverse shoulder patients, with a minimum six-year follow-up using stereo radiographic techniques. Methods. To date, seven patients with a self-reported well-functioning Aequalis Reversed II (Wright Medical Group, Edina, MN, USA) RTSA implant system have been imaged (mean years from surgery = 7.0, range = 6.2 to 9). Using stereo radiographs, patients were imaged at the extents of their range of motion in internal and external rotation, lateral abduction, forward flexion, and with their arm at the side. Multiple arm positions were used to account for the multiple wear vectors associated with activities of daily living and the shoulder's six degrees of motion. Using proprietary software, the position and orientation of the polyethylene and glenosphere components were identified and their transformation matrices recorded. These transformation matrices were then applied to the CAD models of each component, respectively, and the apparent intersection of the glenosphere into the PE recorded. Using previously validated in-house software, volumetric and maximum linear wear depth measurements were obtained. Linear regression was used to identify wear rates. Results. The volumetric and linear wear rates for the 36 mm PE liners (n = 5) were 39 mm. 3. /y (r. 2. = 0.86, range = 24 to 42 mm. 3. /y) and 0.09 mm/y (r. 2. = 0.96, range = 0.08 to 0.11 mm/y), respectively. Only two patients with 42 mm PE liners were evaluated. For these, volumetric and linear wear rates were 110 mm. 3. /y (r. 2. = 0.81, range = 83 to 145 mm. 3. /y) and 0.17 mm/y (r. 2. = 0.99, range = 1.12 to 1.15 mm/y), respectively. Conclusion. For the first time, PE wear was evaluated in the reverse shoulder in vivo. More patients are required for conclusive statements, but preliminary results suggest first order volumetric and linear wear rates within those predicted by simulation studies. It is interesting to note the increased wear with larger PE size, likely due to the increased contact area between congruent faces and the potential for increased sliding distance during arm motion

Introduction. Inadequate stability of the baseplate is a leading cause of revision within reverse total shoulder arthroplasty (rTSA). Micromotion between baseplate and bone is commonly used as a pre-clinical indicator for clinical stability (ASTM F2028-14). Finite element analysis (FEA) has been shown to accurately predict baseplate-bone micromotion, but results may be critically dependent on several modeling assumptions. Here, FEA was used to assess the impact of key modeling assumptions related to screw-bone interactions on various rTSA configurations. Methods. FEA with Ansys ver. 16 was used to simulate a fixation experiment. Baseplates of two different sizes (25mm and 28mm diameter), each with a central screw and four peripheral screws, were virtually implanted in a synthetic bone block. Each baseplate was analyzed using 1.5mm and 3.5mm superior-inferior (SI) offsets of the glenosphere center, as well as using four (‘4S’) and two (‘2S’) peripheral screws. A clinically relevant loading of 756N was applied in compression as well as in inferior-to-superior shear direction through the glenosphere (Figure 1A, 1B). Screw-bone block interactions were modeled in three different ways: (1) Threads were defeatured from the peripheral screws, which were bonded to the bone block (b-nt); (2) Threads were modeled, while still assuming bonded contact (b-t); (3) Threads were modeled, with frictional contact between threads-bone block (f-t). Micromotion results (Figure 1C) from all 24 simulations (3 screw-bone interactions × 2 baseplate diameters × 2 SI offsets × 2 screw configurations) were compared. Results. Across all 24 configurations, the f-t screw-bone interaction resulted in increased micromotion relative to the corresponding bonded simulations. Differences between the two bonded simulations varied among configurations (Figure 2). Screw configuration: For all baseplate diameters, SI offsets, and screw-bone interactions, the 4S configuration had less micromotion (7–20%) than the corresponding 2S configuration (Figure 2). SI Offset: For all baseplate diameters, screw configurations, and screw-bone interactions, the 1.5mm SI offset configuration predicted higher micromotion than the corresponding 3.5mm SI offset configuration (increase of 5–18%), except for the 25mm baseplate in b-nt condition (12–19% decrease) (Figure 3A). Baseplate diameter: For all screw configurations and SI offsets, the f-t modeling assumption resulted in decreased micromotion (5–12%) for the 28mm baseplate as compared to the 25mm baseplate. This trend was reversed for select screw configurations and SI offsets for the other two (b-nt, b-t) modeling assumptions (Figure 3B). Discussion. This study highlights the importance of FEA model fidelity (the level of rigor with which the screw-bone interface is modeled) on evaluating differential performance between rTSA baseplate configurations within a single design family. Three different levels of rigor were considered, based on whether or not the screw threads were explicitly modeled, and on the level of friction allowed between the screw and the bone block. Results highlight that answers to basic questions on relative baseplate performance (e.g. is a 25mm or 28mm baseplate more stable?) are sensitive to these assumptions, and require adequate model validation. Increased care should be taken when conducting evaluations across multiple device families, when additional variables (e.g. screw pitch/torque) are present that could confound analyses

INTRODUCTION. Preoperative planning software for reverse total shoulder arthroplasty (RTSA) allows surgeons to virtually perform a reconstruction based off 3D models generated from CT scans of the glenohumeral joint. While anatomical studies have defined the range of normal values for glenoid version and inclination, there is no clear consensus on glenoid component selection and position for RTSA. The purpose of this study was to examine the distribution of chosen glenoid implant as a function of glenoid wear severity, and to evaluate the inter-surgeon variability of optimal glenoid component placement in RTSA. METHODS. CT scans from 45 patients with glenohumeral arthritis were planned by 8 fellowship trained shoulder arthroplasty specialists using a 3D preoperative planning software, planning each case for optimal implant selection and placement. The software provided four glenoid baseplate implant types: a standard non-augmented component, an 8° posterior augment wedged component, a 10° superior augment wedged component, and a combined 8° posterior and 10° superior wedged augment component. The software interface allowed the surgeons to control version, inclination, rotation, depth, anterior-posterior and superior-inferior position of the glenoid components in 1mm and 1° increments, which were recorded and compared for final implant position in each case. RESULTS. Two cases were excluded due to extreme deformity and consensus that a feasible RTSA may not be possible. For resultant implant version, a bimodal distribution was observed with a local maxima occurring at 0°, and a bell-shaped distribution at −5° of version. Upon individual surgeon analysis, it was revealed that certain surgeons had a preference to correct to 0 degrees, whereas others were more accepting of residual version. As well, the surgeons accepting residual retroversion removed less bone on average per implant type than the surgeons who aimed to correct to 0°. For resultant implant inclination, surgeons consistently tried to plan for 0 degrees of inclination. CONCLUSION. This study indicates that while there was limited consensus on the optimal reconstruction in any one case, there appear to be thresholds of retroversion and inclination that favor the use of augmented glenoid components based on frequency of selection. Our results indicate a wide variability in terms of what experienced shoulder surgeons consider to be an optimal reconstruction despite the common goal of attempting to restore anatomy, maximize implant fixation in bone and minimize bone removal. High frequency of augmented glenoid component use raises questions about how much retroversion and inclination is optimal and whether this technology allows surgeons to potentially focus more on a quantitative reconstruction relative to the Friedman axis versus a qualitative implant placement relative to what may be normal anatomy for a patient

Background:. The use of reverse total shoulder arthroplasty (RTSA) has been increasing around the world. However, because of concerns over lack of internal rotation with the reverse prosthesis and the resultant difficulties with activities of daily living (ADLs), many have recommended against performing bilateral RTSA. Methods:. We performed a retrospective review of prospectively obtained clinical data on 15 consecutive patients (30 shoulders) that underwent staged bilateral primary RTSA for the diagnosis of cuff tear arthropathy (CTA) between 2004 and 2012. All operations were performed by a single surgeon. The mean follow-up was 29.6 months from the second RTSA (range 12–65 months). The mean age of the patients at the time of the first operation was 72.9 years (range 63–79 years), and the mean duration between arthroplasties was 21.6 months (range 8–50 months). Patients were evaluated preoperatively and postoperatively at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and yearly with standardized clinical exams and outcome measures questionnaires including Constant, ASES, UCLA, Simple Shoulder Test, SPADI, and SF-12 scores. Results:. On both operative sides, elevation showed significant improvement from preoperative values (p = 0.002 and p = 0.021); however, external rotation, abduction, and internal rotation did not show significant differences at an average follow-up of 29.6 months. The SPADI, Constant, ASES, UCLA, and SST scores of both RTSA shoulders showed significant improvement from preoperative values (p ≤ 0.001 for all scores); however, the SF-12 scores on either shoulder did not show significant improvement. Evaluation of the outcome measures questionnaire revealed that all 15 patients in the cohort were able to perform perineal hygiene after their reverse arthroplasty. Conclusions:. Bilateral RTSA results in marked improvement in forward elevation, pain, and functional outcomes, and carries a high rate of satisfaction in subjective patient assessment. In addition, common ADLs that require significant internal rotation, such as perineal care, were not problematic in the patients studied

Introduction. Proper positioning of the baseplate and optimal screw placement are necessary to avoid loosening or failure of the glenoid component in RTSA. Several in vitro and anatomic studies have documented ideal number, size, length and angulation of baseplate screws. However, such fixation can often be tenuous, as the anatomy of scapula bone varies. Furthermore, it can be difficult to identify regions with the best bone stock intraoperatively even though surgeons have an understanding of scapular anatomy with potential screw trajectories in mind. This often leads to variable screw lengths and angulations in the clinical setting. The purpose of this study was to measure optimal screw lengths and angles to reach ideal regions in cadaveric scapulae and to compare the clinical experiences of three surgeons with each other and against a cadaveric model with screw lengths and angulations. Materials and Methods. Seven cadaveric scapulae were used as the template for optimal screw angulation and length for baseplate implantation. Total 21 cases (seven cases of each 3 surgeons) of reverse total shoulder arthroplasty using the Aequalis®-Reversed shoulder prosthesis (Tornier, France) were included. Measurement of screw angulation was done on the AP and axillary views to account for the superior-inferior and the antero-posterior angulations, respectively. The screw lengths used on each scapula was recorded prior to insertion in cadavers and retrieved from the operative records in clinical cases. Screws directed anteriorly and superiorly were recorded as positive values while posteriorly and inferiorly directed screws were designated negative values. The significant differences in degrees of screw angulation and screw lengths among the 3 surgeon groups were calculated using the ANOVA, with the p value at 0.05. The Mann-Whitney U test was performed to evaluate the cadaver group against the surgeon groups. Results. In cadaveric specimens, the averages of the screw lengths used were 29.4 mm (anterior screw), 15.4 mm (posterior screw), 36.0 mm (superior screw), and 46.70 mm (inferior screw). The anterior screw was directed 6.9° inferior and 7.5° degrees posterior in reference to the central peg. The posterior screw direction was inferior (−5.0°) and posterior (−1.7°); Superior screw was directed superiorly (30.1°) and anteriorly (22.2°), while the inferior screw was aimed inferiorly (−15.3°) and posteriorly (−8.3°). In clinical cases, the differences in screw length among the 3 surgeon groups were not statistically significant. There was no significant difference in screw angulation among the 3 surgeons except posterior screw. Comparing cadaveric specimens from the clinical cases, the anterior screws were shorter and directed more superiorly and anteriorly in the patients, and the superior and inferior screws were directed less superiorly and inferiorly in the patient. Conclusion. We concluded that more vertical screw placement of the superior and inferior screws is necessary to obtain the ideal baseplate fixation

Introduction. Reverse total shoulder arthroplasty (RTSA) is a commonly performed operation for a variety of pathologies. Despite excellent short-term outcomes, complications are commonly encountered. Recurrent instability occurs in up to 31% of cases, often due to components placed with too little tension. Acromial stress fractures can occur in up to 7% of cases, often due to components placed in too much tension. Despite these concerns, there is little evidence evaluating the intraoperative tension and glenohumeral contact forces (GHCF) during RTSA. The purpose of this study was to measure the intraoperative GHCF during RTSA. Methods. 26 patients were enrolled after obtaining IRB approval. Inclusion criteria were patients undergoing primary RTSA. An instrumented strain gauge implant was designed to attach to an Exactech Equinoxe (Gainesville, FL) baseplate during RTSA. A specially designed trial glenosphere was then attached to the instrumented baseplate. Wires from the strain gauges were connected to a 24-bit analog input and placed outside the operative field to a computer that measure the forces. After joint reduction, GHCF were measured in neutral, passive flexion, passive abduction, passive scaption and passive external rotation (ER). Five patients were excluded due to wire calibration issues. Results. 21 patients were enrolled. The average age was 70 (range 54–84). The average height was 169.5cm (range 154.9–182.9), and average weight was 82.7 kg (range 45.4–129.3) There were 11 females and 10 males. There were thirteen 42mm glenospheres and eight 38mm glenospheres used. The mean GHCF values were 135N at neutral, 123N at ER, 165N in flexion, 110N in scaption, and 205N in abduction. The mean force values were significantly affected by joint position (p=0.002). The mean force at terminal abduction is significantly greater than the mean force at terminal ER and terminal scaption (p<0.05). Conclusion. This study demonstrates that an intraoperative measurement of GHCF can be successfully performed during RTSA using strain gauges. GHCF during RTSA are at their lowest in scaption and ER. They are at their maximum in abduction. Surgeons should keep these findings in mind during trialing to potentially reduce complications associated with inappropriate intraoperative tensioning

INTRODUCTION. Determining proper joint tension in reverse total shoulder arthroplasty (rTSA) can be a challenging task for shoulder surgeons. Often, this is a subjective metric learned by feel during fellowship training with no real quantitative measures of what proper tension encompasses. Tension too high can potentially lead to scapular stress fractures and limitation of range of motion (ROM), whereas tension too low may lead to instability. New technologies that detect joint load intraoperatively create the opportunity to observe rTSA joint reaction forces in a clinical setting for the first time. The purpose of this study was to observe the differences in rTSA loads in cases that utilized two different humeral liner sizes. METHODS. Ten different surgeons performed a total of 37 rTSA cases with the same implant system. During the procedure, each surgeon reconstructed the rTSA implants to his or her own preferred tension. A wireless load sensing humeral liner trial (VERASENSE for Equinoxe, OrthoSensor, Dania Beach, FL) was used in lieu of a traditional plastic humeral liner trial to provide real-time load data to the operating surgeon during the procedure. Two humeral liner trial sizes were offered in 38mm and 42mm curvatures and were selected each case based on surgeon preference. To ensure consistent measurements between surgeons, a standardized ROM assessment consisting of four dynamic maneuvers (maximum internal to external rotation at 0°, 45°, and 90° of abduction, and a maximum flexion/extension maneuver) and three static maneuvers (arm overhead, across the body, and behind the back) was completed in each case. Deidentified load data in lbf was collected and sorted based on which size liner was selected. Differences in means for minimum and maximum load values for the four dynamic maneuvers and differences in means for the three static maneuvers were calculated using 2-tailed unpaired t-tests. RESULTS. No significant differences were observed for the flexion/extension maneuver between the 38mm and 42mm liner sizes, but a significant difference was observed for every internal/external rotation assessment at 0°, 45°, and 90° of abduction. No significant differences were observed for the across the body and overhead maneuvers, but a significant difference was observed for the behind the back maneuver (p = 0.015). Standard deviations were pronounced across all maneuvers. CONCLUSION. This study observed significant differences in intraoperative load values in rTSA when comparing different humeral liner sizes. Limitations of this study include the small sample sizes and large standard deviations observed, as well as comparing across multiple patients and multiple surgeons. Area for future work includes comparing load values with postoperative functional results and complication risks for short, midterm, and long-term outcomes in efforts to find the optimal load range for a given patient

Introduction:. Given that factors like center of rotation (COR), neck shaft angle, glenosphere diameter and component tilt alter the biomechanics of reverse total shoulder arthroplasty (rTSA), the performance of the total rTSA system is of interest. This study compared the composite performance of two rTSA systems that were designed around a medialized or lateralized glenohumeral COR. The objective was to quantify the following outcome measures: 1) COR & humeral position; 2) range of glenohumeral abduction; 3) force to abduct; and 4) range of internal (IR)/external (ER) rotation. Methods:. Seven pairs of shoulders were tested with a biomechanical shoulder simulator. Beads were implanted in the scapula and humerus to quantify bone positions with a fluoroscope. Spectra lines simulated the deltoid and the rotator cuff. Linear actuators simulated muscle excursion while load cells recorded applied force. Diode arrays were used to quantify arm position and calculate the humeral center of rotation. Native specimens were tested where a motion path was recorded from resting to peak glenohumeral abduction in the scapular plane. The trajectory was replayed and deltoid force vs. arm position was recorded. With the elbow flexed, the arm was articulated to maximal internal and external rotation to determine ROM limits due to impingement or soft tissue constraint. Specimens were implanted with a Tornier Aequalis Reversed Shoulder prosthesis (“A,” 36 mm glenosphere, 10° humeral retroversion, 9 mm poly insert – “medial”) or a DJO Surgical Reverse Shoulder Prosthesis (“R,” 32 mm, 30° retroversion, neutral insert/shell – “lateral”). Implants were randomized between shoulders in a pair. After implantation the test protocol was repeated. Paired-t tests (p ≤ 0.050) were adjusted with Holm's step-down correction for multiple comparisons. Results:. Joint COR shifted inferiorly (A = 7 ± 3 mm, R = 4 ± 2 mm) and medially (A = 19 ± 4 mm, R = 12 ± 3 mm) for both systems with respect to native (p≤0.007, between systems p≤0.037). All humeri shifted inferiorly with respect to native (Fig. 1, p = 0.000, between systems p = 0.718). The RSP maintained a nearly anatomic medial/lateral humerus position, whereas the Aequalis medialized the humerus (p = 0.007). Both rTSA systems showed adduction deficit versus native arms (Fig. 2, p ≤ 0.046). Peak passive abduction, IR and ER were not significantly different between systems (p ≥ 0.113) or with respect to native (p ≥ 0.085). Deltoid force required to elevate the arm decreased ∼25% after rTSA (p ≤ 0.049), but did not differ between systems (p ≥ 0.117). Discussion:. Understanding the implications of implant configuration is imperative to improving implant design and optimizing patient outcomes. As tested, the configurations represent over 70% of respective clinical cases. The systems varied in COR offset, humeral component version/tilt, glenosphere placement, and insert thickness, yet few kinematic differences arose. The RSP COR was more lateral than the Aequalis, yet both were medial to native. Accordingly, both systems provided a similar mechanical advantage by reducing the abduction forces. The RSP had the least adduction deficit, which could indicate increased inferior clearance around the more lateral COR. Inferior and medial humerus shift could negatively impact external rotation capability by moving the posterior cuff line of action below the COR and reducing muscle tension (Fig. 3)

Although reverse total shoulder arthroplasty (TSA) may restore shoulder abduction and forward flexion in the setting of a massive rotator cuff tear, the ability to use the extremity for ADL’s is often limited by external rotation weakness. Even though the reverse TSA restores abduction, the patient may be unable to bring the hand to his or her mouth because with the elbow flexed the weight of the hand causes the shoulder to fall into internal rotation. Concomitant transfer of latissimus dorsi (LDT) to the posterior greater tuberosity is a solution advocated by some surgeons. It is hypothesized that this inferiorly-directed force partially counteracts the superiorly-directed force of the deltoid, resulting in decreased shear forces on the glenoid baseplate-bone interface. Three cadaver shoulder specimens were dissected and implanted with the reverse TSA. The rotator cuff was completely released to simulate a massive rotator cuff tear. Each shoulder was mounted in a shoulder controller that simulates neuromuscular control and replicates in vivo glenohumeral kinematics. The controller utilizes an optical, three dimensional tracking system. The humerus was weighted to simulate the full mass of the upper extremity and stepper motors were connected to the insertion points of the anterior, middle and posterior divisions of the deltoid by Spectra. ®. cord. Simulated active abduction in the scapular plane was performed using position closed-loop feedback control. The joint reaction force at the glenosphere was measured at 5° intervals from 30°–70°. A fourth stepper motor was then connected to the greater tuberosity with 2.73kg applied to simulate a LDT and the test was repeated. Five trials were performed under each condition. Four-factor ANOVA statistical analysis with Bonferroni correction and α = 0.05 was performed. After simulated LDT the JRF demonstrated an increase in magnitude at abduction angles between 30° and 65° inclusive (p=0.033). The superiorly-directed shear force was significantly decreased as a result of the LDT between 45° and 70° (p< 0.0001). The compressive component of the JRF was increased for all abduction angles (p=0.025). The force required to achieve abduction increased for the middle deltoid (p=0.035) and anterior deltoid (p=0.036) for the simulated LDT condition at all abduction angles. The posterior deltoid force required for abduction decreased at all abduction angles (p=0.031). In this model of reverse total shoulder arthroplasty concomitant transfer of latissimus dorsi decreased the superiorly-directed shear force. In addition to providing improved external rotation strength, these lower shear forces may have a protective effect on baseplate fixation by reducing the risk of failure in shear. This may provide additional justification for the transfer. Although superior shear was decreased, total JRF was increased as a result of an increase in the compressive component. Further investigation is needed to determine the potential gain in joint stability and whether the glenoid bone can support such elevated compressive forces. Additionally, the force required in the anterior and middle deltoid was increased after the LDT. This indicates the need for sufficient deltoid strength and rehabilitation

Introduction & Background. Clinical outcome after reverse total shoulder arthroplasty (RTSA) can be influenced by technical and implant-related factors, so the purpose of this study was to investigate whether individualizing humeral retroversion and subscapularis repair affect the clinical outcomes after RTSA. Material & Method. Authors retrospectively analyzed the prospectively collected data from 80 patients who underwent RTSA from January 2007 to January 2015 using same implant (Biomet Comprehensive. ®. Reverse Shoulder System, Warsaw, Indiana). The mean follow up was 23.3 ± 1.7 (range, 12 ∼ 70) months. The retroversion of humeral component was decided according to native version estimated using shoulder CT in Group I (n=52), and fixed in 20° retroversion in Group II (n=28). Group I was subdivided into Group Ia (n=21, mean 19.3°), less than 20° of retroversion, and Group Ib (n=31, mean 31.9°), more than 20°. Intraoperative tenotomized subscapularis was repaired in 40 patients in Group I, and could not be repaired due to massive tear including subscapularis in remaining 12 patients. Clinical outcomes were evaluated with range of motion (ROM) and several clinical outcome scores. Results. Group I showed significantly better ROM and clinical scores compared to Group II at the final follow up (all p < 0.05). There were no significant differences in ROM and clinical scores between Group Ia and Ib. Group Ia showed better ROM and pain VAS than Group II (all p < 0.05), and Group Ib also demonstrated significantly better ROM and clinical outcome scores than Group II (all p < 0.05). With respect to subscapularis repair, there were no differences in ROM and clinical scores between two groups. No complications such as infection or dislocation were detected according to subscapularis repair. Conclusion. Individualizing humeral retroversion can obtain superior clinical outcomes than fixed 20° retroversion. Subscapularis repair would not be essential for the better clinical outcome in patients with the lateralized RTSA

Introduction. Current modeling techniques have been used to model the Reverse Total Shoulder Arthroplasty (RTSA) to account for the geometric changes implemented after RTSA [2,3]. Though these models have provided insight into the effects of geometric changes from RTSA these is still a limitation of understanding muscle function after RTSA on a patient-specific basis. The goal of this study sought to overcome this limitation by developing an approach to calibrate patient-specific muscle strength for an RTSA subject. Methods. The approach was performed for both isometric 0° abduction and dynamic abduction. A 12 degree of freedom (DOF) model developed in our previous work was used in conjunction with our clinical data to create a set of patient-specific data (3 dimensional kinematics, muscle activations (), muscle moment arms, joint moments, muscle length, muscle velocity, tendon slack length (), optimal fiber length, peak isometric force)) that was used in a novel optimization scheme to estimate muscle parameters that correspond to the patient's muscle strength[4]. The optimization varied to minimize the difference between measured (“in vivo”) and predicted joint moments and measured (“in vivo”) and predicted muscle activations (). The predicted joint moments were constructed as a summation of muscle moments. The nested optimization was implemented within matlab (Mathworks). The optimization yields a set of muscle parameters that correspond to the subject's muscle strength. The abduction activity was optimized [4,5]. To validate the model we predicted dynamic joint moment and activation for the abduction activity (Figure 1). Results. The muscle activation for the lateral deltoid had a normalized correlation of value of .91(Figure 1 left). The maximum joint moment produced was 18 newton-meters. The joint moments were reproduced to an value of 1 (Figure 1 Right). Muscle parameters were calculated for both isometric and dynamic abduction. The muscle parameters produced provided a feasible solution to reproduce the muscle activation and joint moments seen “in vivo” (Figure 1). Discussion. Current modeling techniques of the upper extremity focus primarily on geometric changes and their effects on shoulder muscle moment arms. In efforts to create patient-specific models we have developed a framework to predict subject-specific strength characteristics. In order to fully understand muscle function we need muscle parameters that correspond to the subject's strength. This effort in conjunction with patient-specific models that incorporate the patient's joint configurations, kinematics and bone anatomy provide a framework to gain insight into muscle tensioning effects after RTSA. This framework describes the relationship between muscle lengthening and muscle performance (recruitment and force generation). With this framework improvements can be made to the surgical implementation and design of RTSA to improve surgical outcomes. Significance. This abstract is the first of its kind to use patient-specific fluoroscopy kinematics, muscle activation and joint moments to create a framework to predict a patients muscle function (activation, force) for RTSA groups. This now allows us to understand how differences in implant design and surgical technique affect each muscle's ability to generate force and function. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

There are a variety of sizes currently available for reverse total shoulder arthroplasty (RTSA) implant systems. Common sizing options include a smaller 36 to 38 mm or a larger 40 to 42 mm glenosphere, and are typically selected based on surgeon preference or patient size. Previous studies have only evaluated the abduction and adduction range of motion within a single plane of elevation, providing a limited view of the joint's possible range of motion. The purpose of this study was to use computer modeling to evaluate the abduction and adduction range of motion across multiple planes of elevation for a range of glenosphere sizes. Computed tomography images of four cadaveric specimens (age: 54 ± 24 years) were used to obtain the osseous anatomy to be utilised in the model. Solid-body motion studies of the RTSA models were constructed with varying glenosphere diameters of 33, 36, 39, 42, and 45 mm in Solidworks (Dassault Systems, US). The implant components were scaled, while maintaining a consistent centre of rotation. Simulations encompassing the full range of abduction and adduction were conducted for the planes of elevation between −15˚ and 135˚ at 15˚ intervals, with the motion of the humerus being constrained in neutral internal-external rotation throughout all planes. Angles of elevation were obtained utilising the humeral long axis and the RTSA centre of rotation. Statistical analysis was performed using repeated measures ANOVA. Glenosphere diameter was found to significantly affect the adduction range of motion (p=0.043), in which the largest size provided approximately 17˚ more adduction range of motion than the smallest. However, abduction range of motion was not found to be significantly affected through the alteration of glenosphere size (p=0.449). The plane of elevation was not found to significantly affect abduction or abduction (p=0.585 & p=0.225, respectively). Increasing glenosphere diameter resulted in an increased adduction range of motion when averaged across the tested planes of elevation; however the observed influence on abduction was not significant. These are similar to the trends observed in the previous single plane of elevation studies. These findings illustrate the importance of implant sizing related to range of motion. Further studies are required to determine the influence of glenosphere size on internal and external range of motion

Reverse total shoulder arthroplasty (RTSA) has had rapidly increasingly utilization since its approval for U.S. use in 2004. RTSA accounted for 11% of extremity market procedure growth in 201. Although RTSA is widely used, there remain significant challenges in determining the location and configuration of implants to achieve optimal clinical and functional results. The goal of this study was to measure the 3D position of the shoulder joint center, relative to the center of the native glenoid face, in 16 subjects with RTSA of three different implant designs, and in 12 healthy young shoulders. CT scans of 12 healthy and 16 pre-operative shoulders were segmented to create 3D models of the scapula and humerus. A standardized bone coordinate system was defined for each bone (Figure 1). For healthy shoulders, the location of the humeral head center was measured relative to the glenoid face center. For the RTSA shoulders, a two-step measurement was required. First, 3D models of the pre-operative bones were reconstructed and oriented in the same manner as for healthy shoulders. Second, 3D model-image registration was used to determine the post-operative implant positioning relative to the bones. The 3D position and orientation of the implants and bones were determined in a sequence of six fluoroscopic images of the arm during abduction, and the mean implant-to-bone relationships were used to determine the surgical positioning of the implants (Figure 2). The RTSA center of rotation was defined as the offset from the center of the implant glenosphere to the center of the native glenoid face. The center of rotation in RTSA shoulders varied over a much greater range than the native shoulders (Table 1 (Figure 3)). Lateral offset of the joint center in RTSA shoulders was at least 6 mm smaller than the smallest joint center offset in the healthy shoulders. The center of rotation in RTSA shoulders was significantly more inferior than in healthy shoulders. The range of anterior/posterior placement of the rotation center for RTSA shoulders was bounded by the range for normal shoulders. How to best position RTSA implants for optimal patient outcomes remains a topic of great debate and research interest. We found that the 3D joint center position can vary over a supraphysiologic range in shoulders with RTSA, and that this variation is primarily in the coronal plane. By relating these geometric variations to muscle, shoulder and clinical function, we hope to establish methods and strategies for predictably obtaining the best clinical and functional outcomes for RTSA patients on a per-subject basis

INTRODUCTION. The advent of CT based 3D preoperative planning software for reverse total shoulder arthroplasty (RTSA) provides surgeons with more data than ever before to prepare for a case. Interestingly, as the usage of such software has increased, further questions have appeared over the optimal way to plan and place a glenoid implant for RTSA. In this study, a survey of shoulder specialists from the American Shoulder and Elbow Society (ASES) was conducted to examine thought patterns in current RTSA implant selection and placement. METHODS. 172 ASES members completed an 18-question survey on their thought process for how they select and place a RTSA glenoid implant. Data was collected using a custom online Survey Monkey survey. Surgeon answers were split into two cohorts based on number of arthroplasties performed per year: between 0–75 was considered low volume (LV), and between 75–200+ was considered high volume (HV). Data was analyzed for each cohort to examine differences in thought patterns, implant selection, and implant placement. RESULTS. 70 surgeons were grouped into the LV cohort, and 102 surgeons were grouped into the HV cohort. 46.1% of surgeons in the HV cohort reported using a preoperative planning software for the majority of cases, 48% reported seldom use, and 5.9% reported no use. In the LV cohort, 41.4% reported use for the majority of cases, 24.3% reported seldom use, and 34.3% reported no use (Figure 1). When questioned on what percentage of RTSA cases do surgeons use augmented glenoid implants, 26.7% in the HV cohort responded never using augments vs. 32.4% in the LV cohort, 32.7% responded using augments <15% of the time in the HV cohort vs. 30.9% in the LV cohort, 26.7% responded using augments between 15–45% of the time in the HV cohort vs. 27.9% in the LV cohort, and 13.8% responded using augments >45% of the time in the HV cohort vs. 8.8% in the LV cohort (Figure 2). When asked what the maximum allowable superior inclination for a RTSA glenoid implant is, surgeons answered 10° 20.6% of the time in the HV cohort vs. 30% in the LV cohort, 5° 18.6% of the time in the HV cohort vs. 25.7% in the LV cohort, 0° 38.2% of the time in the HV cohort vs. 25.7% in the LV cohort, and no fixed degree 22.5% of the time in the HV cohort vs. 18.6% in the LV cohort (Figure 3). CONCLUSION. The results of this study show that even within a group of highly trained surgeons, there are widely varying opinions on how to plan the optimal RTSA case. Variation between high and low volume surgeons reveals even greater differences, suggesting that experience affects thought pattern. Despite these differences, there is no way to prove the optimal implant selection and placement without consistent data collection and long-term clinical outcomes. Machine learning on large preoperative planning databases combined with clinical outcomes data may provide further clarity on optimal implant placement and selection. For any figures or tables, please contact the authors directly

Reverse Total shoulder arthroplasty (RTSA) has become an increasingly used solution to treat osteoarthritis and cuff tear arthropathy. Though successful there are still 10 to 65% complication rates reported for RTSA. Complication rates range over different reverse shoulder designs but a clear understanding of implant design parameters that cause complications is still lacking within the literature. In efforts to reduce complication rates (Implant fixation, range of motion, joint stiffness, and fracture) and improve clinical/functional outcomes having to do with proper muscle performance we have employed a computational approach to assess the sensitivity of muscle performance to changes in RTSA implant geometry and surgical placement. The goal of this study was to assess how changes in RTSA joint configuration affect deltoid performance. An approach was developed from previous work to predict a patient's muscle performance. This approach was automated to assess changes in muscle performance over 1521 joint configurations for an RTSA subject. Patient-specific muscle moment arms, muscle lengths, muscle velocities, and muscle parameters served as inputs into the muscle prediction scheme. We systematically varied joint center locations over 1521 different perturbations from the in vivo measured surgical placement to determine muscle activation and normalized operating region for the anterior, lateral and posterior aspects of the deltoid muscle. The joint center was varied from the RTSA subject's nominal surgical position ±4 mm in the anterior/posterior direction, ±12mm in the medial/lateral direction, and −10 mm to 14 mm in the superior/inferior direction. Overall muscle activity varied over 1521 different implant configurations for the RTSA subject. For initial elevation the RTSA subject showed at least 25% deltoid activation sensitivity in each of the directions of joint configuration change(Figure 1). Posterior deltoid showed a maximal activation variation of 84% in the superior/inferior direction(Figure 1c). Deltoid activation variations lie primarily in the superior/inferior and anterior/posterior directions. An increasing trend was seen for the anterior, lateral and posterior deltoid outside of the discontinuity seen at 28°(Figure 1). Activation variations were compared to subject's experimental data. Reserve actuation for all samples remained below 4Nm(Figure 2). The most optimal deltoid normalized operating length was implemented by changing the joint configuration in the superior/inferior and medial/lateral directions(Figure 3). Current shoulder models utilize cadaver information in their assessment of generic muscle strength. In adding to this literature we performed a sensitivity study to assess the effects of RTSA joint configurations on deltoid muscle performance in a single patient-specific model. For this patient we were able to assess the best joint configuration to improve the patients muscle function and ideally their clinical outcome. With this information improvements can be made to the surgical placement and design of RTSA on a patient-specific basis to improve functional/clinical outcomes while minimizing complications. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Reverse Total shoulder arthroplasty (RTSA) has become an increasingly used solution to treat osteoarthritis and cuff tear arthropathy. Though successful there are still 10 to 65% complication rates reported for RTSA. Complication rates range over different reverse shoulder designs but a clear understanding of implant design parameters that cause complications is still lacking within the literature. In efforts to reduce complication rates (Implant fixation, range of motion, joint stiffness, and fracture) and improve clinical/functional outcomes having to do with proper muscle performance we have employed a computational approach to assess the sensitivity of muscle performance to changes in RTSA implant geometry and surgical placement. The goal of this study was to assess how changes in RTSA joint configuration affect deltoid performance. An approach was developed from previous work to predict a patient's muscle performance. This approach was automated to assess changes in muscle performance over 1521 joint configurations for an RTSA subject. Patient-specific muscle moment arms, muscle lengths, muscle velocities, and muscle parameters served as inputs into the muscle prediction scheme. We systematically varied joint center locations over 1521 different perturbations from the in vivo measured surgical placement to determine muscle normalized operating region for the anterior, lateral and posterior aspects of the deltoid muscle. The joint center was varied according to previous published work from the RTSA subject's nominal surgical position ±4 mm in the anterior/posterior direction, ±12mm in the medial/lateral direction, and −10 mm to 14 mm in the superior/inferior direction (Walker 2015 et al. Table 2). Overall muscle normalized operating length varied over 1521 different implant configurations for the RTSA subject. Ideal muscle normalized operating length variations were found to be in all the fundamental directions that the joint was varied. The anterior deltoid normalized operating length was found to be most sensitive with joint configurations changes in the anterior/posterior medial/lateral direction. It lateral deltoid normalized operating length was found to be most sensitive with joint configurations changes in the medial/lateral direction. It posterior deltoid normalized operating length was found to be most sensitive with joint configurations changes in the medial/lateral direction. Reserve actuation for all samples remained below 1 Nm. The most optimal deltoid normalized operating length was implemented by changing the joint configuration in the superior/inferior and medial/lateral directions. Current shoulder models focus on predicting muscle moment arms. Although valuable it does not allow me for active understanding of how lengthening the muscle will affect its ability to generate force. Our study provides an understanding of how muscle lengthening will affect the force generating capacity of each of the heads of the deltoid. With this information improvements can be made to the surgical placement and design of RTSA to improve functional/clinical outcomes while minimizing complications. For any figures or tables, please contact the authors directly

Purpose:. The reverse total shoulder arthroplasty (RTSA) was approved for use by the United States FDA in 2004. Since its introduction, its popularity for treating a number of shoulder conditions has grown considerably. However, many patients inquire about the potential to return to playing recreational golf, and at present there are no published data about how the RTSA prosthesis affects the golf swing. The purpose of this study is to evaluate the biomechanics of the golf swing in patients with RTSA, as well as the postoperative changes in handicap, driving distance, and holes played/week. Methods:. A review of patient records for those that had an RTSA placed between June 2004 and December 2008 was performed. These patients were sent a questionnaire inquiring about details of golfing before and after RTSA. Patients who were still golfing after implantation of the RTSA prosthesis were selected for six-camera motion analysis testing of their golf swing. Computer analysis program was used to calculate parameters to biomechanically describe the golf swing. Results:. Of the 97 patients that had an RTSA placed during the specified time period, 23 patients responded to the questionnaire and only 3 patients had ever and were still playing golf. A mean increase of 2.3 points in the handicap as well as a 33.3 yard decrease in driving distance was observed. The number of holes played per week decreased by 12 postoperatively. Motion analysis of the golf swings in patients with an RTSA showed decreased motion compared to high handicap golfers at the peak of the backswing at every shoulder parameter measured (forward flexion, horizontal adduction, external rotation); however, these differences were not statistically significant. The mean postoperative external rotation in our patients was 26.2°. Discussion:. Though patients can return to golf after RTSA, self-reported trends towards worse handicaps, decreased driving distances, as well as decreased number of holes played/week were found. Furthermore, the RTSA prosthesis changes the biomechanics of the shoulder, resulting in alterations in ROM, specifically external rotation. Patients with the prosthesis in the leading and trailing shoulders compensate by increasing rotation through their torso during follow-through or increasing abduction during the backswing, respectively. Slower swing speeds during backswing and downswing were also observed. Conclusion:. Patients can continue to play golf after RTSA; however, they may observe slower swing speeds, increases in their preoperative handicaps, as well as decreased driving distances. Possible changes in their swing may also occur that will require compensatory mechanisms to complete a full swing

Reverse total shoulder arthroplasty (RTSA) is a well established treatment that provides reproducible results in the treatment of shoulder arthritis and rotator cuff deficiency in the older patient population. However, the results of arthroplasty in younger, more active patients are currently unclear and not as predictable. The purpose of this study is to evaluate the mid-term results of RTSA for patients aged younger than 60 years. A retrospective review of twenty-six patients (twenty six RTSAs) with a mean age of 58.3 years was performed. Minimum follow-up of 5 years was available at a mean follow-up of 73.3 months postoperatively (range, 60–84 months). The preoperative conditions compelling RTSA were as follows: failed rotator cuff repair (17), fracture sequelae (5), failed arthroplasty (1), and cuff tear arthropathy (CTA) (3). We assessed range-of-motion and strength, visual analog scale, American Shoulder and Elbow Surgeons (ASES), and Constant scores. Radiographs were also evaluated for component loosening and scapular notching. All patients were analyzed radiologically and clinically using patient-reported outcome measures. Active forward elevation improved from 56° to 134° and average active external rotation improved from 10.0° to 19.6°. Scores measured with a visual analog pain scale, the Constant score, and the American Shoulder and Elbow Surgeons (ASES) scale all improved significantly. The Visual analog scale (VAS) score for pain improved from 7.5 to 3.0 and the ASES score improved from 31.4 to 72.4, respectively. The normalized postoperative mean Constant score was 88.03. No radiograph showed loosening of the implant at follow-up. Complications included one traumatic subscapularis rupture at six weeks, and one case of periprosthetic fracture. The remaining twenty-four patients were satisfied with the outcome at the time of the latest follow-up and had returned to their desired activity. RTSA in younger patients provided significant subjective improvement in self-assessed shoulder comfort and substantial gain in overall function. Implant loosening and glenoid wear did not appear to be concerns in the mid-term despite the high activity levels of younger patients. Longer-term studies are required to determine whether similar results are maintained over time

The treatment of rotator cuff arthropathy due to irreparable massive rotator cuff tear is still challenging. We performed reverse total shoulder arthroplasties for 2 cases of cuff tear arthropathy. The short term follow-up after the surgery reveal excellent results by ASES and UCLA score. However, these results still require long term follow-up and the study about implant design for the shoulder anatomy of the Koreans

There is ongoing debate regarding the optimal surgical treatment of complex proximal humeral fractures in elderly patients. The aim of this study was to evaluate the cost-effectiveness of reverse total shoulder arthroplasty (RTSA) compared to hemiarthroplasty (HA) in the management of these fractures. A cost–utility analysis using decision tree and Markov modelling based on data from the published literature was conducted. A single-payer perspective with a lifetime time horizon was adopted. A willingness to pay threshold of CAD $50,000 was used. The incremental cost-effectiveness ratio (ICER) was used as the study's primary outcome measure. In comparison to HA, the incremental cost per QALY gained for RTSA was $13,679. One-way sensitivity analysis revealed the model to be sensitive to the RTSA implant cost and the RTSA procedural costs. Two-way sensitivity analysis suggested RTSA could also be cost-effective within the first two years of surgery with an early complication rate as high as 25% (if RTSA implant cost was approximately $3,000); or conversely, RTSA implant cost could be as high as $8,500 if its early complication rates were 5%. The ICER of $13,679 is well below the WTP threshold of $50,000 and probabilistic sensitivity analysis demonstrated that 92.6% of model simulations favoured RTSA. Our economic analysis found that RTSA for the treatment of complex proximal humeral fractures in the elderly is the preferred economic strategy when compared to HA. The ICER of RTSA is well-below standard willingness to pay thresholds, and its estimate of cost-effectiveness is similar to other highly successful orthopaedic strategies such as total hip arthroplasty for the treatment of hip arthritis

Whilst the use of reverse total shoulder arthroplasty is becoming more common for the treatment of rotator cuff arthropathy, there is still relatively little evidence with regards to its use in complex fractures of the proximal humerus in the elderly. It is increasingly felt to be of use in those patients in whom either internal fixation is not possible due to fracture configuration or bone quality, or in whom there is a rotator cuff deficiency. We report the outcomes of 14 patients with complex 3- or 4-part humeral fractures or delayed presentation of dislocation treated with reverse TSR. Patients were treated within a two year period from January 2011 to December 2013. The average age at time of operation was 75 (50–91 years) with a mean follow-up of 7 months (2–13 months). One patient moved out of area and one lost to follow-up two months following procedure. Reverse TSR was considered a salvage procedure for patients with comminuted proximal humeral fractures or those who presented with irreducible non-acute dislocations. At time of last follow-up all 14 patients were satisfied with the results of their operation and functionally independent with activities of daily living. Range of movement post-operatively was good with mean active forward extension 97° (70–150°) and abduction 101° (80–170°). 43% of patients were pain-free, whilst the remainder only required the use of occasional analgesia. No major post-operative complications were reported. Patients who underwent reverse TSR for dislocation fared better than for those with proximal humeral fractures. The mean active forward extension was 107.5° (90–150°) and abduction 112.5° (90–170°) in the dislocation group (n=5) compared with those who had a fracture in which the forward extension was 91.4° (70–120°) and abduction 95° (80–120°). The results of these patients demonstrate that reverse TSR should be considered in patients with complex proximal humeral fractures or delayed presentation of fractures. It seems to provide consistently excellent pain-relief for patients, with patients either reporting being pain-free or requiring only occasional analgesia. In addition, all patients treated were functionally independent following operation. Range of movement, particularly for those with dislocation, appear good. Further follow-up is required to ensure sustained results but early studies are encouraging

Reverse total shoulder arthroplasty (R-TSA) converts the glenohumeral joint into a ball-and-socket articulation by implanting a metal glenosphere on the glenoid and a concave polyethylene articulation in the humerus. This design increases the stability of the shoulder and is indicated for the treatment of end-stage shoulder arthropathy with significant rotator cuff deficiency. To minimise the risk of loosening, the glenosphere is often medialised (to keep the center of rotation within glenoid bone). Since bone grafting under the glenosphere is recommended as an alternate method to medialisation, we studied the effect of glenosphere placement on the biomechanical efficiency of the deltoid. A musculoskeletal model of the shoulder was constructed using BodySIM (LifeModeler, Inc, San Clemente, CA). The model simulated active dynamic glenohumeral and scapulothoracic abduction in a shoulder implanted with an R-TSA. Muscle forces and gleno-humeral contact forces were computed during shoulder abduction. The following conditions were simulated:. R-TSA with the center of rotation unchanged;. medialisation of center of rotation by 16 mm;. medialisation reduced to 10 mm with a 6-mm bone graft; and. inferior placement of R-TSA by 4 mm to preserve soft-tissue tension and prevent scapular notching. We validated our model by comparing peak glenohumeral contact forces (85% body weight) with previously reported in vivo measurements (Bergmann, J Biomech 2007). Inferior placement of the glenosphere component increased the mechanical advantage of deltoid muscle at 90° abduction by 25%. Medialisation of the glenosphere had little effect on deltoid forces. Reducing the medialisation (to 10 mm, by simulating the effect of a bone graft under the glenosphere) also did not change the mechanical advantage relative to full medialisation (16 mm). One disadvantage of R-TSA is that a center of shoulder rotation outside (lateral) to the glenoid increases the tendency for glenosphere loosening. Unfortunately, medialisation of the glenosphere reduces the tension on the deltoid, increases the incidence of prosthetic impingement resulting in scapular notching, and produces a shoulder contour that is cosmetically undesirable. To counter these disadvantages, reduced medialisation is proposed by bone grafting under the glenosphere and placing the glenosphere inferiorly. Our model indicates that the major mechanical advantage of the R-TSA is provided by the inferior placement of the glenosphere, which increases the moment arm of the deltoid muscle. On the other hand, the extent of glenosphere medialisation had an insignificant effect. These results support the use of reduced medialisation and bone grafting in the presence of other advantages, such as reduced notching and maintenance of infraspinatus tension and improved shoulder contour

Introduction:. Reverse total shoulder arthroplasty (RTSA) has become instrumental in relieving pain and returning function to patients with end-stage rotator cuff disease. A distalized and medialized center of rotation in addition to a semi-constrained implant design allows the deltoid to substitute for the non-functioning rotator cuff. The purpose of this study was to examine the relationship between specific deltoid and rotator cuff muscle parameters and functional outcomes following RTSA. Methods:. Patients undergoing RTSA by a single surgeon were enrolled in a prospective, IRB approved RTSA outcomes registry. Inclusion criteria were diagnosis of cuff tear arthropathy or massive rotator cuff tear, a minimum 2-year follow-up, and a preoperative shoulder MRI. We excluded patients undergoing revision arthroplasty, fracture, and a history of previous open shoulder surgery. For the 28 patients meeting our criteria, the cross-sectional area (CSA) of the anterior, middle, and posterior deltoid were measured on an axial MRI (Figure 1). Fatty infiltration (FI) of the deltoid, supraspinatus (SS), infraspinatus (IS), teres minor, and subscapularis were assessed on sagittal T1-MRI quantitatively via image processing and qualitatively on the 5-point Fuchs scale by a fellowship-trained musculoskeletal radiologist. Outcome measures included active forward elevation (aFE), active external rotation (aER), active internal rotation (aIR), strength in abduction, Constant-Murley score (CMS), Subjective Shoulder Value (SSV), Visual Analogue Scale (VAS) pain, and American Shoulder and Elbow Surgeons (ASES) total and ASES activities of daily living (ADL) scores as assessed by a trained, clinical research nurse. Correlation of deltoid CSA and FI with outcomes measures was analyzed with a Spearman rank correlation coefficient (ρ) with significance at P < .05. Results:. The correlations between preoperative deltoid size and quantitative deltoid FI to postoperative function are shown in Table 1. The total deltoid CSA showed the most significant, positive correlations with outcome measures. The anterior deltoid CSA showed the strongest correlation to postoperative strength in abduction. Quantitative FI of the deltoid was negatively associated with several outcome measures (Table 1). Quantitative FI of the SS and IS demonstrated a significant negative correlation with aER (ρ = −.732, P = .039 and ρ = −.790, P = .004, respectively). The grade of FI, as assessed using the Fuchs scale, did not correlate to any clinical outcome data. Discussion and Conclusion:. Preoperative deltoid size and FI of the deltoid and the rotator cuff muscles correlate to 2-year functional outcomes following RTSA. The anterior, posterior, and total CSA of the deltoid had significant, positive associations with several outcome measures, whereas FI of the deltoid, SS, and IS had significant, negative associations, particularly with humeral rotation. In the future, optimization of deltoid and rotator cuff muscle function preoperatively may improve functional outcomes in RTSA

Introduction. The use of reverse total shoulder arthroplasty (RSA) is becoming increasingly common in the treatment of rotator cuff arthropathy. In recent years indications for use have expanded to include elderly patients in whom either internal fixation is not possible due to fracture configuration, poor bone quality, or presence of a rotator cuff deficiency. There is however relatively little evidence to support its use in these circumstances. Objective. This study aims to assess the viability of RSA as a salvage procedure in the treatment of complex proximal humeral fractures or irreducible dislocations, quantified in terms of functional outcome, complication rates and patient reported satisfaction. Methods. All patients presenting between January 2011 and December 2013 with a complex 3- or 4-part humeral fracture or a delayed presentation with an irreducible non-acute dislocation, treated with salvage RSA were eligible for inclusion. All operations were performed in a single centre by one of two specialist upper limb surgeons. Standard deltopectoral approach was performed. Tournier reverse fracture stem with two choices of inserts and graft hole in the stem with proximal hydroxyapatite coating was the implant of choice. All patients and underwent a standardised rehabilitation programme. Clinical outcome was measured at final follow up using (1) patient reported satisfaction, (2) clinician measured range of movement (3) complication rate. Results. A total of 16 patients were eligible for inclusion in this study. Mean age at time of operation was 72.8 years (41–91 years) with a mean follow-up of 7 months (2–13 months). At time of last follow-up 100 per cent of patients were satisfied with the results of their operation and functionally independent with activities of daily living. Mean oxford score was 39 (36–48). Range of movement post-operatively had a mean active forward extension 97° (70–150°) and abduction 101° (80–170°). 43% of patients were pain-free, whilst the remainder only required the use of occasional analgesia. One patient developed heterotrophic ossification post operatively and underwent surgical excision. One patient sustained a peri-prosthetic avulsion fracture at 18months treated non-operatively. Patients who underwent RSA for dislocation fared better than for those with proximal humeral fractures. The mean active forward extension was 107.5° (90–150°) and abduction 112.5° (90–170°) in the dislocation group (N=5) compared with those who had a fracture (N= 11) in which the forward extension was 91.4° (70–120°) and abduction 95° (80–120°). Conclusion. Reverse TSA should be considered in patients with complex proximal humeral fractures or delayed presentation with irreducible dislocation. Early results demonstrate good outcomes in terms of patient satisfaction, pain relief and preservation of function. These early result are encouraging however a further study with longer follow-up is required to confirm sustained benefit

Purpose:. Although short term outcomes of reverse total shoulder arthroplasty (rTSA) have been promising, long-term success may be limited due to complications, including scapular notching. Scapular notching has been explained primarily as a mechanical erosion, however, generation of wear debris may lead to further biologic changes contributing to the severity of scapular notching. Highly cross-linked ultra-high molecular weight polyethylene (UHMWPE) has been used routinely in constrained joint applications such as total hip arthroplasty for reduction of wear debris particles. Although rTSA shares similarity in design conformity, conventional UHMWPE remains the gold standard. Methods:. A commercially available hip simulator was converted to a 12-station rTSA wear simulator. Conventional and highly cross-linked UHMWPE humeral liners were subjected to 5,000,000 cycles of alternating abduction-adduction and flexion-extension loading profiles. Every 250,000 cycles, liners were evaluated with gravimetric wear measurements and test serum was collected for morphological characterization of wear particles. Results:. Highly cross-linked UHMWPE liners (36.5 ± 10.0 mm. 3. /million cycle) exhibited significantly lower volumetric wear rates compared to conventional UHMWPE liners (83.6 ± 20.6 mm3/million cycle) (p < 0.001) (Figure 1). The flexion-extension loading profile exhibited significantly higher wear rates for both conventional (p < 0.001) and highly cross-linked UHMWPE (p < 0.001) compared to the abduction-adduction loading profile. Highly cross-linked wear particles had an equivalent circle diameter significantly smaller than wear particles from conventional UHMWPE (p < 0.001) (Figure 2). Highly cross-linked wear particles were also significantly less fibrillar than conventional UHMWPE particles with respect to particle aspect ratio (p < 0.001) and particle roundness (p < 0.001). Conclusion:. This is the first study to examine the effect of cross-linked PE in a rTSA wear simulation. Highly cross-linked UHMWPE liners significantly reduced UHWMPE wear and subsequent particle generation. More favorable wear properties with the use of highly cross-linked UHMWPE may lead to increased rTSA device longevity and fewer complications but must be weighed against the impact of reduced mechanical properties

This biomechanical study aims to assess the different designs of glenospheres in SMR reverse total shoulder replacement in the degree of micromotion following dynamic cyclic loading, and its implication for risk of glenoid component loosening. The eccentric designs of glenospheres allowed greater range of motion from improvement in adduction. The eccentric placement of central fixation peg on the glenosphere has raised concerns of increasing micromotion of the baseplate-bone interface during cyclic loading. In our method, the four different designs of glenospheres were tested; 36mm concentric (Standard), 36mm eccentric, 44mm concentric and 44 eccentric glenospheres. Each glenosphere underwent a thousand cycles of shear loading at four different positions of humeral abduction. The micromotion of each glenosphere baseplate were measured and compared. The 36mm eccentric glenopshere has overall the highest degree of micromotion; its degree of movement was well below the accepted 150 micrometer as the threshold for bony ingrowth inhibition

Introduction. Persistent problems and relatively high complication rates with reverse total shoulder arthroplasty (RTSA) are reported (1, 2). It is assumed that some of these complications are affected by improper intraoperative soft tissue tension. Achieving proper intraoperative soft tissue tension is an obvious surgical goal. However, intraoperative soft tissue tension measurements and methods for RTSA have not been reported. One way to quantify soft tissue tension is to measure intraoperative joint forces using an instrumented prosthesis. Hence, we have developed an instrumented RTSA to measure shoulder joint forces intraoperatively. The goal of this study was to measure intraoperative shoulder joint forces during RTSA. Materials and Methods. The instrumented shoulder prosthesis measures the contact force vector between the glenosphere and humeral tray. This force sensor is a custom instrumented trial implant that can be used with an existing RTSA system (EQUINOXE, Exactech Inc, Gainesville, FL) just as a standard trial implant is used. Four uniaxial foil strain gauges (QFLG-02-11-3LJB, Tokyo Sokki Kenkyujo Co., Ltd., JP) are instrumented inside the sensor. Using a calibration matrix, the three force components were calculated from four strain gauge outputs (3). Sixteen patients who underwent RTSA took part in this IRB approved study. All patients were greater than 50 years of age and willing to review and sign the study informed consent form. After obtaining informed consent for surgery, a standard deltopectoral approach to the shoulder was performed. The instrumented trial prostheses were assembled on the glenoid baseplate instead of a standard glenosphere. After the joint was reduced, joint forces were recorded during cyclic rotation, flexion, scapular plane movement (scaption), and adduction of the shoulder. Strain gauge outputs were recorded during these movements as well as the neutral position just before movements. Mean values of forces with each motion were compared by one-way analysis of variance (ANOVA). A multiple comparisons test was subsequently performed to examine differences between motions. Results. Three sensors failed due to intraoperative breakage of strain gauge wires, leaving 13 subjects with measured joint reaction forces. During abduction, for example, the force vector varied from superior to antero-medial, and the resultant joint force in abduction was 83 N in a representative subject (Figure 1). Average joint reaction forces decreased with shoulder motion from a neutral position to external rotation or scaption. Conversely, they increased with flexion or abduction (Figure 2). Mean force values were not the same for each movement (p = 0.018). Forces recorded during flexion and scaption movements differed significantly (p = 0.012). Discussion. The intraoperative forces acting in the RTSA have been measured for the first time, and these measurements are ongoing. We expect more measurements will permit surgeons objectively to place and align implant components to achieve predictable and durable RTSA results

INTRODUCTION: The reverse DELTA III shoulder prosthesis can successfully relieve pain and restore function in cuff tear arthropathy. The most frequently reported complication is inferior scapular notching. The purpose of this study was to evaluate the clinical relevance of notching and to determine the anatomic and radiographic parameters that predispose to its occurrence. STUDY PROTOCOL: Seventy-seven consecutive shoulders of 76 patients of an average age of 71 years with an irreparable rotator cuff deficiency were treated with a reverse DELTA III shoulder arthroplasty and followed clinically and radiographically under fluoroscopic control for a minimum of 24 months (mean: 44, range: 24 to 96). The effect of glenoid cranial caudal component positioning and of the prosthesis–scapular neck angle on the development of inferior scapular notching and clinical outcome was assessed. RESULTS: All shoulders which developed notching did so in the first fourteen months. Forty-four percent of the shoulders had inferior scapular notching, 30% had posterior notching and anterior notching (8%) was rare. Osteophytes along the inferior scapula occurred in 27% of the shoulders. The angle between the glénosphère and the scapular neck (r=+0.677)) as well as the craniocaudal position of the glénosphère (r=+0.654) were highly correlated with inferior notching (p< 0.001). A notching index (notching index = height of prosthesis + (prosthesis scapular neck angle x 0.13) was calculated using the height of implantation of the glénosphère and the postoperative prosthesis scapular neck angle: This allowed a prediction of the occurrence of notching with a sensitivity of 91% and specificity of 88%. The height of implantation of the glenosphere had a greater influence on inferior notching than the prosthesis scapular neck angle by a factor of approximately 1:8. Inferior scapular notching was associated with a significantly poorer clinical outcome than absence of inferior notching: At final follow-up, the respective average subjective shoulder values were 62% and 71% (p=0.032), relative Constant scores were 72% and 83% (p=0.028), abduction strength was 4.3 versus 8.7 kilograms (p< 0.001), active abduction was 102° versus 118° (p=0.033) and flexion averaged 110° versus 127° (p=0.004). DISCUSSION: Inferior scapular notching after reverse total shoulder arthroplasty adversely affects midterm clinical outcome. It can be prevented by optimal positioning of the glenoid component

Reverse total shoulder replacement is a viable surgical option for Cuff Tear Arthropathy. Short term results have been promising. Longer term follow-up has demonstrated a high rate of scapular notching. This is attributed to mechanical impingement between the humeral cup and scapular neck when the arm is fully adducted. The long term sequelae of scapular notching are unclear but there is concern that it may compromise fixation of the glenoid component and affect functional outcomes. Design modifications to address this problem include the newly available eccentric glenospheres and larger diameter glenospheres. These glenospheres are designed to offer greater ranges of motion and theoretically may reduce the risk of impingement and notching. The purpose of this biomechanical study is to demonstrate the difference in range of motions with each design of glenosphere. To our knowledge there is no published literature evaluating this design differences. The SMR (Lima Orthotec) reverse total shoulder prothesis was implanted into a synthetic bone model (Sawbones, Pacific Laboratories, Vashon, Washington). Four different types of glenospheres (Standard 36 mm, Eccentric 36 mm, Standard 44 mm, Eccentric 44 mm) were then implanted into the same model which was fixed on a measurement table. The precision coordinate measurement device (FARO-Arm, SO6/Rev22, FARO Technologies Inc., Lake Mary, Florida) was used to establish the centres of rotation and ranges of motion. To date, the collection of data has just been completed, but the data are yet to be analysed. In conclusion, this is a biomechanical study evaluating the ranges of motion and risk of notching, comparing different designs of glenospheres in Reverse Total Shoulder Joint Replacement

Latissimus dorsi anterior to major transfers have been advocated in the setting of loss of external rotation and elevation in conjunction with reverse shoulder replacement. Reverse shoulder replacement is a prosthesis specifically designed for shoulders with poor rotator cuff function. In the vast majority of cases, some teres minor function at the minimum is maintained in shoulders destined for a reverse shoulder replacement. However, in certain circumstances there is complete loss of any external rotation, and a muscle transfer can be performed in order to restore some external rotation function. A reverse shoulder replacement in the absence of any rotator cuff function goes into obligate internal rotation with elevation. A minimum of external rotation strength is necessary in order to maintain the arm in normal rotation. The first tip is patient selection. Physical examination of active external rotation, external rotation strength and forward elevation should be just performed. A latissimus transfer is indicated in patients who cannot maintain their arm in neutral to at least a few degrees of external rotation. A lag sign is another physical examination finding which can indicate complete loss of rotator cuff function. The latissimus dorsi transfer is performed by first identifying and releasing the latissimus from its insertion on the anterior humerus. The arthroplasty is performed. The passage for the latissimus muscle is developed carefully and being mindful of the axillary nerve in particular. The latissimus is directed inferior to the nerve and around the medial and posterior aspect of the proximal humerus. Different ways of securing the transfer to the humerus have been described including bone tunnels and anchors. Often it is easier to place the anchors and/or the bone tunnels prior to inserting the humeral prosthesis. The latissimus is secured in the new position, enabling it to participate in external rotation. The value of this is difficult to clearly establish. Most studies are evidence level IV and there are no good comparative studies in a controlled patient population. This is a good option for shoulders with no active external rotation, but they may increase overall complication rate. Complications include dislocation, infection, and transient nerve palsy.

Introduction. Lateralizing the center of rotation (COR) of reverse total shoulder arthroplasty (rTSA) has the potential to increase functional outcomes of the procedure, namely adduction range of motion (ROM). However, increased torque at the bone-implant interface as a result of lateralization may provoke early implant loosening, especially in situations where two, rather than four, fixation screws are used. The aim of this study was to utilize finite element (FE) models to investigate the effects of lateralization and the number of fixation screws on micromotion and adduction ROM. Methods. Four patient-specific scapular geometries were developed from CT data in 3D Slicer using a semi-automatic threshold technique. A generic glenoid component including the baseplate, a lateralization spacer, and four fixation screws was modelled as a monoblock. Screws were simplified as 4.5 mm diameter cylinders. The glenoid of each scapula was virtually reamed after which the glenoid component was placed. Models were meshed with quadratic tetrahedral elements with an edge length of 1.3 mm. The baseplate and lateralization spacer were assigned titanium material properties (E = 113.8 GPa and ν = 0.34). Screws were also assigned titanium material properties with a corrected elastic modulus (56.7 GPa) to account for omitted thread geometry. Cortical bone was assigned an elastic modulus of 17.5 GPa and Poisson's ratio of 0.3. Cancellous bone material properties in the region of the glenoid were assigned on an element-by-element basis using previously established equations to convert Hounsfield Units from the CT data to density and subsequently to elastic modulus [1]. Fixed displacement boundary conditions were applied to the medial border of each scapula. Contact was simulated as frictional (μ = 0.8) between bone and screws and frictionless between bone and baseplate/spacer. Compressive and superiorly-oriented shear loads of 686 N were applied to the baseplate/spacer. Lateralization of the COR up to 16 mm was simulated by applying the shear load further from the glenoid surface in 4 mm increments (Fig. 1A). All lateralization levels were simulated with four and two (superior and inferior) fixation screws. Absolute micromotion of the baseplate/spacer with respect to the glenoid surface was averaged across the back surface of the spacer and normalized to the baseline configuration considered to be 0 mm lateralization and four fixation screws. Adduction ROM was measured as the angle between the glenoid surface and the humeral stem when impingement of the humeral cup occurred (Fig. 1B). Results. Lateralization (p = 0.015) and reducing the number of fixation screws (p = 0.008) significantly increased micromotion (Fig. 2). Lateralization significantly increased adduction ROM (p = 0.001). Relationships between lateralization, the number of fixation screws, micromotion, and adduction ROM were shoulder-specific (Fig. 3). Conclusions. Lateralizing the COR of rTSA can improve functional outcomes of the procedure, however may compromise long-term survival of the implant by increasing micromotion. Our results indicate that the trade-offs of lateralizing should be considered on a patient-specific basis, taking into account factors such as quality and availability of bone stock

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.

Introduction:. Reverse total shoulder arthroplasty (RTSA) has become an accepted surgical treatment for patients with severe deficiency of the rotator cuff. Despite the utility of RTSA in managing difficult shoulder problems, humeral rotation does not reliably improve and may even worsen following RTSA. Several approaches to increase active external rotation (aER) postoperatively have been proposed including the use of concomitant latissimus dorsi tendon transfer (LDTT) or the use of an increased lateral-offset glenosphere (LG). We hypothesized that clinical outcome and range of motion after RTSA with a +4 mm or +6 mm LG would be comparable to RTSA with LDTT in patients with a lack of aER preoperatively. Methods:. An IRB-approved, prospective, single surgeon RTSA registry was reviewed for patients treated with LDTT or LG for preoperative aER deficiency with minimum 1-year follow-up. Patients qualified for aER deficiency if they had a positive ER lag sign or less than or equal to 10 degrees of aER preoperatively. Matched control groups with patients that did not have preoperative lack of aER and were not treated with LDTT or LG were included for comparison. Outcomes measures included Constant-Murley score (CMS), American Shoulder and Elbow Surgeons (ASES) score, Subjective Shoulder Value (SSV), ASES Activities of Daily Living (ADL) score, Visual Analogue pain Scale (VAS), active forward elevation (aFE), active internal rotation (aIR), and aER. An independent, institutional biostatistician performed statistical analyses. Results:. The LDTT group had 21 patients (10 male, 11 female) and the LG group had 16 patients (5 male, 11 female). CMS, ASES, SSV, ADL, VAS, and aFE were significantly improved in case and control groups following RTSA (P < .05). There was no significant difference in the degree of improvement of CMS, ASES, SSV, ADL, VAS or aFE between the LDTT group and its control group or the LG group and its control group (P > .05). aER was significantly improved in the LDTT and LG groups (P < .001), but did not improve significantly in either control group (P > .05) (Figure 1). The LDTT group had a significantly lower postoperative aER than its control group (P = .001), whereas the LG group had similar postoperative aER to its control group (P = .376) (Figure 1). The LG group had significantly greater aER preoperatively and postoperatively than the LDTT group (P < .001 and P = .013). There was no significant difference in degree of improvement of aER between the LDTT and LG groups (P = .212). The LDTT group had a significantly lower postoperative aIR than its control group (P=.025), whereas the LG group had similar postoperative aIR to its control group (P = .234). The LG group had significantly greater improvement in aIR than the LDTT group (P=.009). Conclusion:. To our knowledge, this is the first series to compare outcomes of two common techniques used to improve aER following RTSA. In this series, we found overall similar improvements in outcomes between the groups. These results suggest that use of a LG may be preferable to LDTT given the relatively simplified surgical technique, similar improvement in aER, comparable clinical outcome scores, and the added benefit of improved aIR

Reverse shoulder arthroplasty (RSA) has an increasing effective use in the treatment of patients with a variety of diagnoses, including rotator cuff deficiency, inflammatory arthritis, or failed shoulder prostheses. Glenoid bone loss is not uncommonly encountered in these cases due to the significant wear. Severe bone loss can compromise glenoid baseplate positioning and fixation, consequently increasing the risk for early component loosening, instability, and scapular notching. To manage severe glenoid bone deficiencies, bone grafts are commonly used. Although, many studies report outcome of bone grafting in revision RSA, the literature on humeral head autograft for glenoid bone loss in primary RSA is less robust. The purpose of this study is to evaluate the clinical and radiographic outcomes of primary RSA with humeral head autograft for glenoid bone loss at our institution.

Institutional review board approval was obtained to retrospectively review the records of 22 consecutive primary RTSA surgeries in 21 patients with humeral head autograft for glenoid bone loss between January 2008 and December 2016. Five patients died during follow-up, three were unable to be contacted and one refused to participate, leaving a final study cohort of 12 patients with 13 shoulders that underwent RSA. All patients had a clinical evaluation including detailed ROM and clinical evaluation using the American Shoulder and Elbow Surgeons (ASES) Score, Constant Score, Western Ontario Osteoarthritis of the Shoulder Index (WOOS), and Short Form-12 (SF-12) questionnaires. Preoperative and postoperative plain radiographs and CT scans were assessed for component position, loosening, scapular notching, as well as graft incorporation, resorption, or collapse.

There were 6 males and 6 females, with an average age of 74 ± 6.8 years. The average BMI was 31.7 ± 5.3, and the median ASA score was 3. Average follow-up was 3.4 ± 1.1 years. The average postoperative range of motion measurements for the operative arm are: flexion = 120 ± 37, abduction = 106 ± 23, external rotation = 14 ± 12, internal rotation at 90 degrees of abduction = 49 ± 7, external rotation at 90 degrees of abduction = 50 ± 28. Average functional scores are: ASES: 76.9 ± 19.2, WOOS: 456 ± 347, SF12 physical: 34.2 ± 8.2, SF12 mental: 54.1 ± 10.2, Constant Score: 64.6 ± 14. No evidence of hardware loosening or evidence of bone graft resorption were encountered. On CT, the average of pre operative B-angle was 79.3 ± 9.3 while the pre operative reverse shoulder angle was 101.4 ± 28. Glenoid retroversion average on CT was 13.3 ± 16.6. Post operative baseplate inclination average was 82 ± 7.4 while the baseplate version 7.8 ±10. The operative technique was able to achieve up to 30 degrees of inclination correction and up to 50 degrees of version correction.

In conclusion, primary reverse shoulder arthroplasty with humeral head autograft for glenoid bone loss provides excellent ROM and functional outcomes at mid-term follow-up. This technique has a high rate of bone incorporation and small risk of bone resorption at mid term follow up.

INTRODUCTION

Retrieval analysis is an important aspect of medical device development. Examination of retrieved devices allows device developers to close the design loop, understand the performance of devices, and validate assumptions made and methods used during preclinical testing. We provide an overview of the implant retrieval analysis performed at the Implant Research Center at Drexel University on reverse total shoulder systems retrieved after short to medium term implantation.

Modern total shoulder arthroplasty seeks to produce a construct that reproduces the kinematics and stability of the native glenohumeral joint. The latest 4th generation implants are modular, adaptable, and capable of use as either anatomic or reverse shoulder arthroplasty components. During surgery, these implants are “universal”; post-operatively, they are “convertible”.

Recent work has demonstrated that reverse shoulder arthroplasty components may indeed be the emerging standard of care for most (if not all) shoulder arthroplasty indications.

As this new frontier develops, the use of a convertible/universal implant creates the flexibility to individually choose the best surgical option for each patient.

Introduction

Machine learning is a relatively novel method to orthopaedics which can be used to evaluate complex associations and patterns in outcomes and healthcare data. The purpose of this study is to utilize 3 different supervised machine learning algorithms to evaluate outcomes from a multi-center international database of a single shoulder prosthesis to evaluate the accuracy of each model to predict post-operative outcomes of both aTSA and rTSA.

Introduction:

Studies have demonstrated both clinical and radiological success of reverse shoulder arthroplasty (RTSA), with follow-up approaching 10-years. To date, most RTSA studies involve cemented fixation of the humeral components, and most involving uncemented RTSAs have used implants not necessarily designed for bony ingrowth. Cementless fixation utilizing proximally porous-coated (PPC) femoral implants has shown long term survivorship approaching 99% at greater than 10-years follow-up in total hip arthroplasty. Currently, the number of commercially available PPC RTSA implants is steadily growing, but there has been no published study examining clinical and radiographic outcomes in PPC, press-fit humeral stems. We hypothesized that the clinical and radiographic results of uncemented RTSA utilizing a PPC humeral stem would be similar to cemented RTSA stems when followed for at least 2-years.

Introduction

A better understanding of the rate of improvement associated with aTSA and rTSA is critical to establish accurate patient expectations for treatment to reduce pain and restore function; more realistic patient expectations pre-operatively may lead to greater patient satisfaction post-operatively. To this end, this study quantifies the rate of improvement in outcomes of aTSA and rTSA using 5 different scoring metrics for 1641 patients with one platform shoulder arthroplasty system.

Reverse TSA initially followed Grammont's dictum that the center of rotation (COR) must be in the bone (“medial” COR). Others have argued for a more lateral COR, which can be a challenge if glenoid bone stock has been medially eroded. When bone loss must be made up, and/or the COR lateralised, the options include use of bone graft or use of metal.

Metal constructs produce a cantilever-loading situation, with substantial bending moments applied to the bone-implant junction. Use of bone graft allows remodeling with living bone, so that ultimately the forces are applied to the bone-implant junction in a more compressive pattern.

The author's preference is to have at least 30% of the circumference of the baseplate contact living bone while the rest may be made up with bone graft which can remodel. It is important to have a deep keel penetrate the cortex medially.

Lateralization of the reverse arthroplasty may be desirable to more effectively tension the remaining rotator cuff, decrease scapular notching, improve the cosmetic appearance of the shoulder, and improve stability as well as the arc of motion prior to impingement. There are two primary options to lateralise a reverse shoulder arthroplasty: bone graft with a long post (BIO-RSA) vs. using metal. The two metal options generally include a thicker glenosphere or a thicker glenoid baseplate.

Potential benefits of a BIO-RSA include lateralization of the glenoid center of rotation but without placing the center of rotation lateral to the prosthetic-bone interface. By maintaining the position of the center of rotation, the shear forces at the prosthesis-bone interface are lessened and are converted to compressive forces which will minimise glenoid failure.

Edwards et al. performed a prospective study on a bony increased offset reverse arthroplasty. Among the 18 shoulders in the BIO-RSA group, the incidence of notching was 78% compared to controls 70%. The graft completely incorporated in 12 (67%), partially incorporated in 4 (22%), and failed to incorporate in 2 (11%).

Frankle et al. reported on the minimum 5-year follow-up of reverse arthroplasty with a central compression screw and a lateralised glenoid component. The survivorship was 94% at 5 years. There were seven (9%) cases of scapular notching and no patient had glenoid baseplate loosening or baseplate failure. The authors noted that the patients maintained their improved function and radiographic results at a minimum of five years.

In summary, lateralisation of the glenosphere is an attractive option to improve the outcome of reverse arthroplasty. Benefits of lateralisation with metal rather than bone graft include elimination of concern over bone graft healing or resorption. In addition, the procedure has the potential to be more precise with the exact offset amount known pre-operatively as well as improved efficiency of the procedure. Preparing the graft takes additional OR time and there is variable quality of the bone graft.

Introduction

The clinical impact of scapular notching is controversial. Some reports suggest it has no impact while others have demonstrated it does negatively impact clinical outcomes. The goal of this clinical study is to analyze the pre- and post-operative outcomes of 415 patients who received rTSA with one specific prosthesis (Equinoxe; Exactech, Inc).

Background

Use of a baseplate with a smaller diameter in reverse shoulder arthroplasty has been recommended, especially in patients with a small glenoid or insufficient bony stock due to severe glenoid wear. However, effect of a smaller baseplate on stability of the glenoid component has not been evaluated. The purpose of this study was to determine whether a smaller baseplate (25 mm) is beneficial to the initial primary stability of the glenoid component compared to that with a baseplate of a commonly used size (29 mm) by finite element analysis.

Introduction

Both anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty are the standard of care for various end-stage degenerative conditions of the glenohumeral joint. Osteoarthritis (OA) is the most common indication for aTSA while Rotator Cuff Tear Arthropathy (CTA) is the most common indication for rTSA. Worldwide, the usage of both aTSA and rTSA has increased significantly due in part, to the predictability of acceptable outcomes achieved with each prosthesis type. The aim of this study is to quantify outcomes using 5 different metrics and compare results achieved for each indication using one platform total shoulder arthroplasty system which utilizes the same humeral component and instrumentation to perform both aTSA or rTSA.

Introduction

Posterior glenoid wear is common with glenohumeral osteoarthritis. To correct posterior wear, surgeons may eccentrically ream the anterior glenoid to restore version. However, eccentric reaming undermines prosthesis support by removing unworn anterior glenoid bone, compromises cement fixation by increasing the likelihood of peg perforation, and medializes the joint line which has implications on joint stability. To conserve bone and preserve the joint line when correcting glenoid version, manufacturers have developed posterior augment glenoids for aTSA and rTSA applications. This clinical study quantifies outcomes achieved using posteriorly augmented aTSA/rTSA glenoid implants in patients with severe posterior glenoid wear at 2 years minimum follow-up.

Purpose: The objectives of this study were:

to determine if the deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA, and;

The hypotheses were:

that the deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA, and;

Method: Six cadaveric shoulders had all capsule, rotator cuff, and scapulohumeral muscles removed, leaving only the deltoid, conjoint tendon (i.e. coracobrachialis and short head of biceps) and long head of triceps. A RTSA was then performed. A displacing force was then applied perpendicular to the centerline of the humeral socket and this load was increased until dislocation occurred. The load required to cause a dislocation was recorded for superior, inferior, anterior and posterior load directions. This was repeated to measure the effect of humeral component rotation (neutral, 20 degrees retroversion, 20 degrees anteversion), arm position (0 degrees abduction, 60 degrees flexion, 60 degrees abduction and 60 degrees extension) and polyethylene thickness (3, 6 or 9 mm). Statistical analysis used an ANOVA with Tukey post-hoc tests for multiple comparisons (p< 0.05).

Results: The deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA. The required dislocation force was increased for an inferior direction of load application (p0.05). The required dislocation force was least in an arm position of 60 degrees abduction, followed by 60 degrees extension, with no difference between 0 degrees abduction and 60 degrees flexion (p0.05).

Conclusion: The deltoid, conjoint tendon and long head of the triceps provide sufficient soft tissue tension to stabilize a RTSA. Stability of a RTSA was greatest for an inferior directed force and an arm position of 0 degrees abduction or 60 degrees flexion. There was no influence of arm rotation or polyethylene thickness on stability of a RTSA. This study indicates that stability of a RTSA can still be achieved despite significant soft tissue loss, as long as key soft tissue structures remain intact. As well, certain loading directions and arm positions lead to an increased risk of instability. However, further in vivo studies are required.

We retrospectively reviewed 11 consecutive patients with an infected reverse shoulder prosthesis. Patients were assessed clinically and radiologically, and standard laboratory tests were carried out. Peroperative samples showed Propionbacterium acnes in seven, coagulase-negative Staphylococcus in five, methicillin-resistant staphylococcus aureus in one and Escherichia coli in one. Two multibacterial and nine monobacterial infections were seen. Post-operatively, patients were treated with intravenous cefazolin for at least three days and in all antibiotic therapy was given for at least three months. Severe pain (3 of 11) or severe limitation of function (3 of 11) are not necessarily seen. A fistula was present in eight, but function was not affected. All but one patient were considered free of infection after one-stage revision at a median follow-up of 24 months, and without antibiotic treatment for a minimum of six months. One patient had a persistent infection despite a second staged revision, but is now free of infection with a spacer. Complications included posterior dislocation in one, haematoma in one and a clavicular fracture in one. At the most recent follow-up the median post-operative Constant-Murley score was 55, 6% adjusted for age, gender and dominance.

A one-stage revision arthroplasty reduces the cost and duration of treatment. It is reliable in eradicating infection and good functional outcomes can be achieved.

Introduction

Due to the predictability of outcomes achieved with reverse shoulder arthroplasty (rTSA), rTSA is increasingly being used in patients where glenoid fixation is compromised due to presence of glenoid wear. There are various methods to achieve glenoid fixation in patients with glenoid wear, including the use of bone grafting behind the glenoid baseplate or the use of augmented glenoid baseplates. This clinical study quantifies clinical outcomes achieved using both techniques in patients with severe glenoid wear at 2 years minimum follow-up.