Causes of acromion and scapular spine fractures following reverse shoulder arthroplasty: a retrospective analysis and literature review

Low acromial insufficiency fracture rate in reverse shoulder arthroplasty with distal clavicle excision

Background

This study investigated the rate of acromial insufficiency fractures (AIF) in patients undergoing reverse shoulder arthroplasty (RSA) with concomitant distal clavicle excision (DCE).

Methods

Patients who underwent primary RSA with DCE by a single surgeon from 2010 to 2021 were identified. Exclusion criteria included revision RSA, RSA for fracture, or cases utilizing an augmented baseplate or bone graft. AIF was defined as a radiographically proven acromion or scapular spine fracture. Pain without an identifiable fracture on imaging was defined as an acromial insufficiency reaction. Patient demographics, implant information, and radiograph measurements were compared between patients with and without acromial pathology.

Results

One hundred and seventy-five patients were included. Mean age was 72.8 years, and 67% of patients were female. There were 3/174 acromial insufficiency fractures (1.7%). AIF occurred at a mean of 9.3 months after surgery. Twelve patients had insufficiency reactions (6.9%). Patients with acromial pathology were more likely to be female (p = .003) and have a diagnosis of osteoporosis (p = .047) and inflammatory arthritis (p = .049). There was no significant difference between groups in terms of other factors.

Conclusion

The AIF rate in patients who underwent RSA with DCE was 1.7%. These findings suggest that DCE in the setting of RSA may have a protective role against AIF.

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 mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

Outcomes of conservative treatment of acromial and scapular spine stress fracture post reverse shoulder arthroplasty: a systematic review with meta-analysis

INTRODUCTION

Acromial and scapular spine stress fractures are common complications post reverse shoulder arthroplasty. A systematic review with meta-analysis was conducted to evaluate the clinical outcomes of conservatively treated acromial and scapular spine stress fractures post reverse shoulder arthroplasty in comparison to nonfracture control.

METHODS

Embase, MEDLINE, and Web of Science were searched on September 9, 2022, using various terms related to fracture, acromion, scapula, and reverse shoulder arthroplasty. Meta-analysis using a random effects model was performed on common outcome scores. Risk of bias was assessed using the Joanna Briggs Institute tools for case-controlled studies. Sensitivity analysis was performed for imputed standard deviations and studies with <20 participants.

RESULTS

Thirteen studies with a total of 339 fracture and 3142 control patients were included in the systematic review. Meta-analysis was performed on 12 studies assessing active forward flexion, abduction, external rotation, Constant-Murley score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, pain score, Simple Shoulder Test, and Single Assessment Numeric Evaluation. Fracture patients experienced significantly poorer functional outcome compared with control patients when the fractures were managed conservatively. Levy III fractures tend to experience worse outcomes. Pain score did not demonstrate a statistically significant difference between the fracture and nonfracture cohort.

DISCUSSION

Currently, literature regarding surgical management is lacking, partially because of a dearth of high-quality literature but also hindered by a lack of standardized techniques. This review was limited by inclusion of studies of low evidence, small sample sizes, and inconsistency in outcome measurement and follow-up period. Overall, patients with acromial and scapular spine stress fractures treated conservatively are expected to have reduced shoulder function compared to nonfracture patients, with the spine of scapula fracture patients suffering the poorest outcomes. Future studies should aim to use the same sets of outcomes parameters to assess the patients at fixed time intervals and report outcomes stratified by Levy classification. This will enable interinstitutional collaboration and pooling of results.

Mitigating Fracture of the Acromion and Scapular Spine After Reverse Shoulder Arthroplasty: A Critical Analysis Review of Patient and Surgical Risk Factors

LEVEL OF EVIDENCE

Level V. Narrative Review. See Instructions for Authors for a complete description of levels of evidence.

Risk factors of acromial and scapular spine stress fractures differ by indication: a study by the ASES Complications of Reverse Shoulder Arthroplasty Multicenter Research Group

BACKGROUND

Both patient and implant related variables have been implicated in the incidence of acromial (ASF) and scapular spine fractures (SSF) following reverse shoulder arthroplasty (RSA); however, previous studies have not characterized nor differentiated risk profiles for varying indications including primary glenohumeral arthritis with intact rotator cuff (GHOA), rotator cuff arthropathy (CTA), and massive irreparable rotator cuff tear (MCT). The purpose of this study was to determine patient factors predictive of cumulative ASF/SSF risk for varying preoperative diagnosis and rotator cuff status.

METHODS

Patients consecutively receiving RSA between January 2013 and June 2019 from 15 institutions comprising 24 members of the American Shoulder and Elbow Surgeons (ASES) with primary, preoperative diagnoses of GHOA, CTA and MCT were included for study. Inclusion criteria, definitions, and inclusion of patient factors in a multivariate model to predict cumulative risk of ASF/SSF were determined through an iterative Delphi process. The CTA and MCT groups were combined for analysis. Consensus was defined as greater than 75% agreement amongst contributors. Only ASF/SSF confirmed by clinical and radiographic correlation were included for analysis.

RESULTS

Our study cohort included 4764 patients with preoperative diagnoses of GHOA, CTA, or MCT with minimum follow-up of 3 months (range: 3-84). The incidence of cumulative stress fracture was 4.1% (n = 196). The incidence of stress fracture in the GHOA cohort was 2.1% (n = 34/1637) compared to 5.2% (n = 162/3127) (P < .001) in the CTA/MCT cohort. Presence of inflammatory arthritis (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.08-7.78; P = .035) was the sole predictive factor of stress fractures in GHOA, compared with inflammatory arthritis (OR 1.86, 95% CI 1.19-2.89; P = .016), female sex (OR 1.81, 95% CI 1.20-2.72; P = .007), and osteoporosis (OR 1.56, 95% CI 1.02-2.37; P = .003) in the CTA/MCT cohort.

CONCLUSION

Preoperative diagnosis of GHOA has a different risk profile for developing stress fractures after RSA than patients with CTA/MCT. Though rotator cuff integrity is likely protective against ASF/SSF, approximately 1/46 patients receiving RSA with primary GHOA will have this complication, primarily influenced by a history of inflammatory arthritis. Understanding risk profiles of patients undergoing RSA by varying diagnosis is important in counseling, expectation management, and treatment by surgeons.

Octogenarian With Acromion Stress Fracture Nonunion With Reverse Total Shoulder Prosthesis Reconstructed With Plates and Screws: A Case Report

An 85-year-old male underwent open reduction and internal fixation (ORIF) for a displaced acromion stress fracture that occurred two years prior. The complete fracture occurred two months after an ipsilateral reverse total shoulder arthroplasty (RTSA). Four weeks after his RTSA, the pain was felt at the posterior-superior shoulder with activities of his daily living as a rancher, reflecting non-compliant use. A stress fracture was suspected but not detected radiographically. Four weeks later, higher pain occurred after he lifted a hay bale, and a displaced basilar acromion fracture was detected. Non-operative management spanned 20 months, which he ultimately deemed unacceptable because of pain with minor activities. ORIF was then done. Approximately 10 months after the ORIF surgery, both plates sustained fatigue breakage; however, the fracture consolidated, and his pain remained low. He is the oldest patient described to ultimately have a successful acromion fracture ORIF and only the third reported acromion fracture ORIF in octogenarians following RTSA. We report the ORIF technique, its good outcome, and a literature review of elderly patients who had ORIF for this problem.

Update on Shoulder Arthroplasties with Emphasis on Imaging

Shoulder pain and dysfunction may significantly impact quality of life. If conservative measures fail, advanced disease is frequently treated with shoulder arthroplasty, which is currently the third most common joint replacement surgery following the hip and knee. The main indications for shoulder arthroplasty include primary osteoarthritis, post-traumatic arthritis, inflammatory arthritis, osteonecrosis, proximal humeral fracture sequelae, severely dislocated proximal humeral fractures, and advanced rotator cuff disease. Several types of anatomic arthroplasties are available, such as humeral head resurfacing and hemiarthroplasties, as well as total anatomic arthroplasties. Reverse total shoulder arthroplasties, which reverse the normal ball-and-socket geometry of the shoulder, are also available. Each of these arthroplasty types has specific indications and unique complications in addition to general hardware-related or surgery-related complications. Imaging-including radiography, ultrasonography, computed tomography, magnetic resonance imaging, and, occasionally, nuclear medicine imaging-has a key role in the initial pre-operative evaluation for shoulder arthroplasty, as well as in post-surgical follow-up. This review paper aims to discuss important pre-operative imaging considerations, including rotator cuff evaluation, glenoid morphology, and glenoid version, as well as to review post-operative imaging of the various types of shoulder arthroplasties, to include normal post-operative appearances as well as imaging findings of complications.

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.

Single or Double Plating for Acromial Type III Fractures: Biomechanical Comparison of Load to Failure and Fragment Motion

BACKGROUND

Acromial Levy III fractures after inverse shoulder arthroplasty occur in up to 7% of patients. To date, it is not clear how these fractures should be treated as clinical outcomes remain unsatisfactory. The aim of this study was to evaluate the biomechanical performance of three different plating methods of type III acromion fractures.

METHODS

Levy III fractures in synthetic scapulae were fixed with three different methods. Angular stable locking plates were placed on the spina scapula to bridge the fracture either dorsally, caudally, or on both aspects by double plating. In a biomechanical experiment, the pull of the deltoid muscle at 40° abduction of the arm was simulated by cyclic loading with increasing load levels until failure. Failure load, cycles to failure, and fragment motions were evaluated.

RESULTS

The results showed that double plating (350 ± 63 N) withstood the highest loads until failure, followed by dorsal (292 ± 20 N) and caudal (217 ± 49 N) plating. Similarly, double plating showed significantly smaller fragment movement than the other two groups.

CONCLUSIONS

Double plating appeared to provide the largest biomechanical stability in type III acromion fracture under arm abduction. Caudal plating in contract resulted in insufficient fracture stability and early failure and can thus not be recommended from a biomechanical point of view.

Treatment strategies for scapular spine fractures: a scoping review

Fractures of the scapular spine are relatively rare and can occur without (1) or with (2) association to a reverse shoulder arthroplasty (RSA). To date there are only limited data on the topic. The aim of this scoping review was to identify all available literature and report current treatment concepts.

A scoping review was conducted by searching PubMed for relevant studies between 2000 and October 2020. All studies were included which gave detailed descriptions of the treatment strategy.

A total of 21 studies with 81 patients were included for the analysis. The mean age over all patients was 62 years (range: 24 to 89 years) and 77% of the patients were female. In 19.8% of cases, the fracture occurred after a traumatic fall from standing height. Eighty-six per cent of the patients had an RSA-associated scapular spine fracture (2). These patients were older compared to group (1) (47 ± 19.6 vs. 76 ± 5.6 years, p = 0.0001) and the majority were female (85%). The majority from group (1) underwent operative treatment with plate fixation. Most patients regained full function and range of motion. RSA-associated fractures (2) were mainly treated non-operatively, with moderate clinical outcome. A high rate of nonunions was reported.

Scapular spine fractures without RSA are mainly treated operatively with good clinical results. In association with RSA, scapular spine fractures are mainly treated non-operatively and lead to inferior clinical and radiological results. This scenario seems to be problematic and further research is required to sharpen treatment concepts in this group.

Cite this article: EFORT Open Rev 2021;6:788-796. DOI: 10.1302/2058-5241.6.200153

Acromion and Scapular Spine Fractures Following Reverse Total Shoulder Arthroplasty

Reverse total shoulder arthroplasty (RSA) continues to see tremendous growth as the indications have expanded. A variety of complications have been described, including fractures of the acromion or scapular spine. These fractures are painful and can compromise shoulder stability and functional outcomes following RSA. Multiple studies have recently investigated the incidence, risk factors, and treatment strategies for these injuries. In this article, the authors review current literature and discuss the incidence, cause, associated risk factors, treatment options, and outcomes following fractures of the acromion or scapular spine after RSA.