The Evolution of Reverse Total Shoulder Arthroplasty-From the First Steps to Novel Implant Designs and Surgical Techniques

Common Factors in Shoulder and Hip Arthroplasty Implant Failures: A Historical Review

In this era of subspecialty care in orthopedics, iterations of implant design can occur in a silo which then precludes gaining knowledge from failures of implant design that may have occurred in different subspecialties. This literature review describes the history of failures in hip and shoulder arthroplasties with the purpose of identifying similar factors that led to previous implant failures. A review of the literature was performed by two reviewers assessing articles that described failed hip and shoulder arthroplasty systems over time. We identified and analyzed 53 implant failures-23 in hip arthroplasty and 30 in shoulder arthroplasty. These failures were categorized as material, mechanical, and technical. In hip arthroplasty, 48% were material, 39% mechanical, and 13% technical failures. In shoulder arthroplasty, the distribution was 10% material, 70% mechanical, and 20% technical failures. The distribution of these failures highlights similar and sometimes repeated failure mechanisms between subspecialties. This accentuates the importance of a collaborative approach to improve future arthroplasty designs.

Global trends and research hotspots of reverse total shoulder arthroplasty: a bibliometric analysis from 1991 to 2022

Reverse total shoulder arthroplasty (rTSA) has been demonstrated to be an effective intervention for various shoulder disorders. The number of rTSA-related studies performed has increased annually over the past three decades. The Journal of Shoulder and Elbow Surgery had the highest number of publications and citations in the rTSA-related research domain and is therefore considered to be the most influential journal in this field. The USA published the most publications and established a high degree of cooperation with many countries worldwide. The University of Florida, the Hospital for Special Surgery, and Rush University, Mayo Clinic were representative and active institutions in this field. It is anticipated that advancements in prosthesis design, specifically with regards to lateralized design concepts, expanding indications for rTSA, a trend toward younger patient populations, and the management of postoperative complications will emerge as research hotspots in the following years. The most valuable publications, influential journals, major researchers, and leading countries were analyzed. The findings of our study will help researchers gain insights into current research hotspots and frontiers and shape their research focus in the field of rTSA.

Patient-specific implants in reverse shoulder arthroplasty

Reverse total shoulder arthroplasty (RTSA) is widely popular among shoulder surgeons and patients, and its prevalence has increased dramatically in recent years. With this increased use, the indicated pathologies associated with RTSA are more likely to be encountered, and challenging patient presentations are more likely to be seen. One prominent challenging presentation is RTSA patients with severe glenoid bone loss. Several techniques with varying degrees of invasiveness, including excessive reaming, alternate centerline, bone grafting, and patient-specific implants (PSIs), have been developed to treat patients with this presentation. PSI treatment uses a three-dimensional reconstruction of a computed tomography scan to design a prosthetic implant or component customized to the patient's glenoid morphology, allowing compensation for any significant bone loss. The novelty of this technology implies a paucity of available literature, and although many studies show that PSIs have good potential for solving challenging shoulder problems, some studies have reported questionable and equivocal outcomes. Additional research is needed to explore the indications, outcomes, techniques, and cost-efficiency of this technology to help establish its role in current treatment guidelines and strategies.

[Influencing factors on effectiveness of reverse total shoulder arthroplasty]

Objective

To summarize the influencing factors on the effectiveness of reverse total shoulder arthroplasty (RTSA), so as to provide reference for clinical treatment.

Methods

The related research literature of RTSA at home and abroad was extensively consulted, and the factors that may affect the effectiveness were summarized from the aspects of surgical technique, muscle condition, general condition of patients, psychological expectation, and lifestyle.

Results

For surgical techniques, different surgical approaches have their own advantages. The glenoid notch, poor bone ingrowth, increased bone resorption, and infection would lead to the loosening of glenoid prosthesis. In addition, the neck shaft angle and inclination angle of humeral prosthesis affect the occurrence of glenoid notch and the range of motion of joint internal/external rotation after operation, respectively. For muscle condition, the quality of teres minor and deltoid muscle has an important influence on joint stability after operation. Moderate increase of deltoid muscle tension can improve joint mobility after operation, and suture repair of subscapular tendon during operation can relieve joint pain and improve function, range of motion, and strength. For the general condition of patients, gender, age, and body mass index are all related to postoperative joint function and complications, and different occupations and postoperative exercise levels affect the recovery. The patients with severe degenerative diseases, poor preoperative function, and long disease duration have lower expectations and higher satisfaction with the effectiveness, and bad lifestyle has a negative impact on the effectiveness.

Conclusion

The effectiveness of RTSA is related to surgical technique, muscle condition, general condition of patients, psychological expectation, and lifestyle. In order to avoid the loosening of glenoid prosthesis, the operator should choose humeral prosthesis with small neck shaft angle and large glenoid ball and put them down and inclined inferiorly during operation, and choose appropriate approach to eliminate space with drainage to reduce the risk of infection. After operation, patients should avoid activities that generate high anterior and posterior shear forces. In addition, the humeral prosthesis with a inclination angle of 10°-20° can achieve the best balance between the range of internal rotation and external rotation after operation. Proper deltoid tension can maintain joint stability and good range of motion. Suture of subscapular tendon is recommended.

Medium-term results of inlay vs. onlay humeral components for reverse shoulder arthroplasty: a New Zealand Joint Registry study

BACKGROUND

The purpose of this study was to compare medium-term results of inlay and onlay humeral components in reverse shoulder arthroplasty (RSA). Specifically, we report differences in revision rate and functional outcomes between the 2 designs.

METHODS

The 3 most used inlay (in-RSA) and onlay (on-RSA) implants by volume from the New Zealand Joint Registry were included in the study. In-RSA was defined as having a humeral tray that recessed within the metaphyseal bone, whereas on-RSA was defined as having a humeral tray that rested on the epiphyseal osteotomy surface. The primary outcome was revision up to 8 years postsurgery. Secondary outcomes included the Oxford Shoulder Score (OSS), implant survival, and revision cause for in-RSA and on-RSA as well as individual prostheses.

RESULTS

There were 6707 patients (5736 in-RSA; 971 on-RSA) included in the study. For all causes, in-RSA demonstrated a lower revision rate compared to on-RSA (revision rate/100 component years: in-RSA 0.665, 95% confidence interval [CI] 0.569-0.768; on-RSA 1.010, 95% CI 0.673-1.415). However, the mean 6-month OSS was higher for the on-RSA group (mean difference 2.20, 95% CI 1.37-3.03; P < .001). However, this was not clinically significant. At 5 years, there were no statistically or clinically significant differences between the 2 groups with respect to the OSS.

CONCLUSION

The medium-term survival of in-RSA was higher than that of on-RSA. However, functional outcomes at 6 months were better for on-RSA compared to in-RSA. Further follow-up is required to understand the long-term survivorship and functional outcomes between these designs.

Functional assessment and quality of life of patients after reverse total shoulder arthroplasty in the late follow-up period

BACKGROUND

Due to the systematically increasing number of shoulder replacement procedures among older people, the need to assess their quality of life is becoming more and more important.

OBJECTIVE

The aim of the study was to functionally assess the shoulder joint and the quality of life of patients before and after reverse total shoulder arthroplasty (rTSA).

METHODS

The observational study included 15 patients after the rTSA procedure (randomly selected). The quality of life and shoulder joint function before and after rTSA were assessed using the following scales: SF-36, Constant-Murley Score, Disabilities of the Arm, Shoulder and Hand Scale (DASH) and the University of California-Los Angeles Shoulder Rating Scale (UCLA scale) and Simple Shoulder Test (SST).

RESULTS

There were statistically significant differences (p< 0.001) between measurements in the overall scores of the SF-36 questionnaire. Statistically significant differences (p< 0.001) were found between measurements in terms of the Constant-Murley, DASH, UCLA and SST scales results.

CONCLUSIONS

Reverse total shoulder arthroplasty significantly improved the patients' quality of life and the functional condition of the operated limb.

Relationship between the prosthesis scapular neck angle and clinical outcomes in reverse shoulder arthroplasty

Background

Optimal glenosphere positioning in reverse shoulder arthroplasty (RSA) remains highly debated. We aimed to characterize the association between the prosthesis scapular neck angle (PSNA) and postoperative range of motion (ROM) and clinical outcome scores.

Methods

A retrospective review of 284 RSAs using a single design with minimum 2-year follow-up was performed. Glenosphere tilt was measured postoperatively using PSNA. ROM and functional outcome scores were assessed preoperatively and at latest follow-up. The PSNA was dichotomized to inferior or superior groups (>90° vs ≤ 90°, respectively) and stratified into quartiles; ROM and outcome score measures were compared between groups controlling for inferior glenosphere overhang.

Results

No range of PSNA was consistently associated with superior ROM, clinical outcome scores, or rates of complications including scapular notching. However, greater preoperative to postoperative improvement in active FE was found for superiorly (PSNA ≤ 90°) versus inferiorly tilted glenospheres (37° ± 33° vs 53° ± 35°, P  =  0.005) and the greater improvement in active FE (57° ± 35°, P  =  0.004) was further isolated to the first quartile (mean 85.1° ± 3.5°).

Discussion

A lack of variation in clinical outcomes based on PSNA suggests negligible short-term (median follow-up 3.1 years) clinical significance when glenosphere tilt falls within the distribution of this cohort (mean 92.6° ± 6.2°).

Reverse Shoulder Arthroplasty in Nonagenarians - NIS-based study of perioperative and postoperative complications

Purpose

Our aim is to investigate the length of stay (LOS), cost of care (COC) and postoperative complications associated with reverse shoulder arthroplasty (RSA) in nonagenarians (people aged 90-99 years old).

Methods

We used the National Inpatient Sample (NIS) database to identify 59,925 patients who underwent RSA between 2016 and 2019, including 555 nonagenarians. We investigated the incidences of various medical and orthopedic postoperative complications in nonagenarians compared to their younger counterparts, as well as compared nonagenarians undergoing elective and non-elective surgery.

Results

Nonagenarians were less likely admitted for elective surgery (69.9% in nonagenarians vs 92.8% in controls, p < 0.001) and were subject to longer LOS (3.5 days in nonagenarians vs 1.89 days in controls, p < 0.001) and greater COC ($91,794.69 US in nonagenarians vs $79,574.12 US in controls, p < 0.001). Nonagenarians had increased incidences of hospital mortality (0.72% in nonagenarians vs 0.06% in controls, p < 0.001), pneumonia (1.44% in nonagenarians vs 0.37% in controls, p < 0.001), blood loss anemia (22.34% in nonagenarians vs 10.12% in controls, p < 0.001), and ARF (6.85% in nonagenarians vs 2.18% in controls, p < 0.001). Nonagenarians undergoing elective RSA had fewer complications than those requiring non-elective RSA.

Conclusion

Nonagenarians undergoing RSA are subject to increased LOS, COC, and postoperative complications. Despite this, we feel that the associated complications can be deemed acceptable and that with adequate preparation, the benefits of a successful RSA may outweigh the associated complications in elderly patients. This is important to aid clinicians and patients in making informed decisions for patient care and resource allocation, as well as highlights room for improvement in costs and hospital stay, as well as sheds light on persistent health disparities in orthopedic surgery.

Level of evidence

IV.

Implant selection for successful reverse total shoulder arthroplasty

Reverse total shoulder arthroplasty (RTSA) emerged as a new concept of arthroplasty that does not restore normal anatomy but does restore function. It enables the function of the torn rotator cuff to be performed by the deltoid and shows encouraging clinical outcomes. Since its introduction, various modifications have been designed to improve the outcome of the RTSA. From the original cemented baseplate with peg or keel, a cementless baseplate was designed that could be fixed with central and peripheral screws. In addition, a modular-type glenoid component enabled easier revision options. For the humeral component, the initial design was an inlay type of long stem with cemented fixation. However, loss of bone stock from the cemented stem hindered revision surgery. Therefore, a cementless design was introduced with a firm metaphyseal fixation. Furthermore, to prevent complications such as scapular notching, the concept of lateralization emerged. Lateralization helped to maintain normal shoulder contour and better rotator cuff function for improved external/internal rotation power, but excessive lateralization yielded problems such as subacromial notching. Therefore, for patients with pseudoparalysis or with risk of subacromial notching, a medial eccentric tray option can be used for distalization and reduced lateralization of the center of rotation. In summary, it is important that surgeons understand the characteristics of each implant in the various options for RTSA. Furthermore, through preoperative evaluation of patients, surgeons can choose the implant option that will lead to the best outcomes after RTSA.

Influential articles on shoulder arthroplasty: bibliometric analysis and visualized study

BACKGROUND

Shoulder arthroplasty has had increasing global demand, technical development, and research interest in the past few decades, with the publication of numerous articles. However, little is known about the characteristics and evaluation of these articles. Our objective was to study and analyze the top 100 cited articles in shoulder arthroplasty research.

MATERIALS AND METHODS

Publications on shoulder arthroplasty from inception to 2022 were retrieved from the Web of Science. The top 100 publications were defined by the number of citations, and their characteristics were recorded and analyzed. A visualized study of the articles was performed using VOSviewer software.

RESULTS

The top 100 cited articles were published between 1981 and 2018, with the 2000s the most productive decade. Citations per article ranged from 103 to 822. The countries with the most articles were the United States followed by France and Switzerland. Most of the articles were level III evidence. The keywords for the articles were primarily in 5 clusters: infection, fracture, osteoarthritis, perioperative complications, and prosthetic design.

CONCLUSIONS

The characteristics of influential articles on shoulder arthroplasty were thoroughly analyzed. Most studies focused on surgical techniques and perioperative complications with a relatively low level of evidence.

Reverse Shoulder Arthroplasty for Acute Proximal Humerus Fractures Treated With Trabecular Metal Prosthesis: Medium-Term Results

Introduction Reverse shoulder arthroplasty (RSA) is becoming increasingly popular as a primary procedure for complex proximal humeral fractures (PHF) in acute trauma due to more emerging evidence and better patient outcomes. Methods This study is a retrospective case series of 51 patients who underwent a trabecular metal RSA for non-reconstructable, acute three or four-part PHF performed by a single surgeon between 2013 and 2019 with a minimum follow-up of three years. This included 44 females and seven males. Mean age was 76 years (range: 61-91 years). Oxford shoulder score (OSS) along with relevant patient information relating to demographics and functional outcomes were collected at regular intervals in outpatient clinic follow-ups. Complications were addressed accordingly during treatment and follow-up. Results The mean follow-up duration was 5.08 years. Two patients were lost to follow-up and nine patients died due to other causes. Four of them had developed severe dementia and were excluded as an outcome score from them could not be acquired. Two patients who had surgery beyond four weeks post-injury were excluded. Thirty-four patients in total were followed up. Patients had good range of motion and mean OSS of 40.28 post-operatively. The overall complication rate was 11.7%, and none of the patients had deep infections, scapular notching, or acromial fractures. Revision rate was 5.8% at mean follow-up of five years and one month (range: three years to nine years two months). Greater tuberosity union following intra-operative repair was evident on radiographs in 61.7% of the patients. Conclusion RSA is certainly a rewarding surgery in patients with complex PHF and was associated with good post-operative OSS along with patient satisfaction, and positive radiological outcomes at minimum three-year follow-up.