Dislocation following reverse total shoulder arthroplasty

Comparative learning curves for early complications in anatomical and reverse shoulder arthroplasty

Introduction There has been a significant increase in the implantation of reverse shoulder replacements over anatomical shoulder replacements in the past five years. Few comparative data exist comparing early complication rates and learning curves. This study aimed to evaluate the early complication rates and learning curves of a single surgeon series of anatomical and reverse shoulder replacements over the first five years of independent practice. Materials and methods The first 100 anatomical and 100 reverse shoulder replacements performed between July 2011 and July 2016 were reviewed to identify early complications. Cumulative sum plots were used to analyse the learning-curve effect. Results Early complications were noted in 4 anatomical and 17 reverse shoulder replacements. One of the anatomical and ten of the reverse shoulder replacements required a return to theatre within three months. The early complication rates were observed to be significantly higher in the reverse shoulder replacement group compared with the anatomical shoulder replacement group (odds ratio 4.9; 95% confidence interval 1.6-15.2, P 1/4 0.057). An inflection point on the anatomical shoulder replacement cumulative sum plot suggestive of a trend to consistent performance was reached at 16 cases. No inflection point was observed on the reverse shoulder replacement cohort. Conclusions We observed a significantly higher early complication rate within the reverse shoulder replacement cohort, with a tenfold increase in early reoperations. In comparison to the trend seen after 16 cases for anatomical shoulder replacement, no trend was seen in the reverse shoulder replacement cohort. This either reflects the higher complication rate seen in reverse shoulder replacement or that the learning curve extends beyond 100 cases, highlighting the need for extended performance monitoring.

Classification of instability after reverse shoulder arthroplasty guides surgical management and outcomes

BACKGROUND

Revision of unstable reverse shoulder arthroplasty (RSA) remains a significant challenge. The purpose of this study was to determine the reliability of a new treatment-guiding classification for instability after RSA, to describe the clinical outcomes of patients stabilized operatively, and to identify those with higher risk of recurrence.

METHODS

All patients undergoing revision for instability after RSA were identified at our institution. Demographic, clinical, radiographic, and intraoperative data were collected. A classification was developed using all identified causes of instability after RSA and allocating them to 1 of 3 defined treatment-guiding categories. Eight surgeons reviewed all data and applied the classification scheme to each case. Interobserver and intraobserver reliability was used to evaluate the classification scheme. Preoperative clinical outcomes were compared with final follow-up in stabilized shoulders.

RESULTS

Forty-three revision cases in 34 patients met the inclusion for study. Five patients remained unstable after revision. Persistent instability most commonly occurred in persistent deltoid dysfunction and postoperative acromial fractures but also in 1 case of soft tissue impingement. Twenty-one patients remained stable at minimum 2 years of follow-up and had significant improvement of clinical outcome scores and range of motion. Reliability of the classification scheme showed substantial and almost perfect interobserver and intraobserver agreement among all the participants (κ = 0.699 and κ = 0.851, respectively).

DISCUSSION

Instability after RSA can be successfully treated with revision surgery using the reliable treatment-guiding classification scheme presented herein. However, more understanding is needed for patients with greater risk of recurrent instability after revision surgery.

Grammont humeral design versus onlay curved-stem reverse shoulder arthroplasty: comparison of clinical and radiographic outcomes with minimum 2-year follow-up

BACKGROUND

There are few investigations comparing lateralized and medialized reverse total shoulder arthroplasty (RTSA) in patients with cuff tear arthropathy. This study assessed the outcomes of 2 RTSA designs.

METHODS

Sixty-eight consecutive cuff tear arthropathy patients (74 shoulders) with a follow-up of at least 24 months received a Grammont or an onlay curved short-stem humeral component, with or without glenoid lateralization; a cementless humeral stem was implanted in >90%. Clinical outcome measures included active range of motion (anterior and lateral elevation, external and internal rotation), pain, and the Constant-Murley score. Radiologic outcomes included radiolucency, condensation lines, cortical thinning, spot weld, loosening and subsidence, and tuberosity resorption for the humeral component and radiolucency, scapular notching, formation of scapular bone spurs, ossifications, and loosening for the glenoid component.

RESULTS

Both prostheses provided significant differences between preoperative and postoperative scores and showed a similar complication rate. Scapular fractures were found only in the patients who received the curved short-stem implant. Glenoid bone grafting did not significantly affect clinical scores. Both implants provided similar postoperative shoulder mobility, even though the lateralized curved stem was associated with higher delta scores for external rotation (P = .002) and lower rates of scapular notching (P = .0003), glenoid radiolucency (P = .016), and humeral bone remodeling (P = .004 and P = .030 for cortical thinning and spot weld, respectively).

CONCLUSIONS

Medialized and short-stem lateralized RTSA implants provided similar midterm clinical outcomes and range of motion. The curved short stem was associated with higher delta scores for external rotation and a lower rate of radiographic risk factors.

Reverse total shoulder arthroplasty

Since the introduction of reverse total shoulder arthroplasty (RTSA) in 1987 (in Europe) and 2004 (in the United States), the number of RTSAs performed annually has increased.

Although the main indication for RTSA has been rotator cuff tears, indications have expanded to include several shoulder conditions, many of which involve dysfunction of the rotator cuff.

RTSA complications have been reported to affect 19% to 68% of patients and include acromial fracture, haematoma, infection, instability, mechanical baseplate failure, neurological injury, periprosthetic fracture and scapular notching.

Current controversies in RTSA include optimal baseplate positioning, humeral neck-shaft angle (135° versus 155°), glenosphere placement (medial, lateral or bony increased offset RTSA) and subscapularis repair.

Improvements in prosthesis design, surgeon experience and clinical results will need to occur to optimize this treatment for many shoulder conditions.

Cite this article: EFORT Open Rev 2018;3:58–69 DOI: 10.1302/2058-5241.3.170044

Reverse Shoulder Arthroplasty Using a Bone-preserving Glenoid Component: Clinical and Radiographic Outcomes

Introduction

Primary reverse shoulder arthroplasty has been reported to provide good outcomes. The majority of designs utilize a large portion of the glenoid. Some studies have reported worrisome rates of notching and stress fractures of the acromion or scapular spine. The purpose of this study was to determine the outcome and complications of a bone-preserving reverse prosthesis with limited ingrowth glenoid surface paired with an onlay humeral component.

Materials and methods

Between 2014 and 2015, 96 reverse arthroplasties were implanted using a bone-preserving reverse with a 135° onlay humeral bearing. Six patients died. The remaining 87 patients (90 shoulders) were followed for 2 years or until revision. Mean age was 69.3 years. The underlying diagnosis was cuff tear arthropathy (13), irreparable cuff tear (39), osteoarthritis (32), and other (6). Shoulders were followed for 2 years or until revision surgery.

Results

Reverse shoulder arthroplasty resulted in significant improvements in pain, motion, and function. At most recent follow-up, 74 shoulders had no or mild pain. Elevation was 131° ± 31° and external rotation 46° ± 21°. The mean American Shoulder and Elbow Surgeons (ASES) score was 76. There were 4 reoperations for deep infection (2), periprosthetic fracture, and glenoid loosening. None of the remaining arthroplasties were loose. There was one stress fracture of the acromion and one of the spine of the scapula. No radiographic notching or dislocation was observed.

Discussion

Primary reverse arthroplasty using a bone-preserving glenoid component and an anatomic onlay humeral bearing provides satisfactory clinical outcomes with a very low rate of failure and complications.