Anatomical reconstruction to treat acromion fractures following reverse shoulder arthroplasty. Int Orthop. 2018;42:875-881. [PMID: 29222664 DOI: 10.1007/s00264-017-3710-0]

How to choose the best lateralization and distalization of the reverse shoulder arthroplasty to optimize the clinical outcome in cuff tear arthropathy

BACKGROUND

Lateralization shoulder angle (LSA) and distalization shoulder angle (DSA) are 2 parameters that have been described for a better planification of arthroplasty, but the range of these angles is very wide. The purpose of this study was to investigate the best combination in terms of lateralization and distalization to optimize the outcome of reverse total shoulder arthroplasty (RTSA) for cuff tear arthropathy (CTA) with a functional deltoid.

METHODS

This retrospective cohort study, conducted between 2014 and 2018 at a specialized shoulder unit in Paris, focused on patients exclusively treated with RTSA for CTA, ensuring a minimum follow-up of 1 year. The primary outcome measure was the American Shoulder and Elbow Surgeons (ASES) score. Secondary outcome measures included range of motion and patient-reported outcomes at the final follow-up, such as the Constant score, Subjective Shoulder Value, Simple Shoulder Test, and visual analog scale. Optimal RTSA outcomes were delineated by scores surpassing the patient's acceptable symptom state for ASES, set in literature at 76. Patients were categorized into 2 groups based on ASES scores at the last follow-up: those below and those above 76. The capabilities of LSA and DSA to predict the outcome of interest were assessed, and the corresponding optimal thresholds for having a better outcome were calculated using the receiver operating characteristic curve.

RESULTS

Sixty-two patients with a mean age of 74.51 ± 6.79 years were included in the study. Correlation analysis revealed a significant medium correlation between ASES and both LSA (r = -0.43, P = .001) and DSA (r = 0.39, P = .002). The DSA of patients with ASES >76 was 48.55° ± 12.44° with an interquartile range (IQR) of 39.5°-57.5°, as compared with the lower value for patients with ASES <76, which was 37.82° ± 9.8° (IQR: 32°-46.5°, P = .009). Similarly, the LSA of patients with ASES >76 was 86.43° ± 11.4° (IQR: 79.5°-93.5°), as compared with the higher value for patients with ASES <76, which was 100.09° ± 7.63° (IQR: 93°-105.5°, P < .001). The receiver operating characteristic curve confirmed LSA and DSA as good predictors for the ASES outcome, with areas under the curve of 0.851 and 0.741, respectively. The optimal LSA should be no more than 90.5° (sensitivity = 100%, specificity = 67.7%). The optimal DSA should be no less than 37.5° (sensitivity = 78.4%, specificity = 63.6%).

CONCLUSION

The LSA and DSA could represent a helpful tool to optimize the clinical outcomes of an adaptable RTSA in CTA with a functional deltoid and a complete passive range of motion.

Operative treatment of acromial and scapular spine fracture nonunions complicating reverse total shoulder arthroplasty

BACKGROUND

Fractures of the acromion and spine can have a major impact on the outcome of reverse shoulder arthroplasty (RSA) with respect to pain, motion, and function. Reports on internal fixation for these fractures are isolated to small series or case reports with variable outcomes. The purpose of this study was to report on the outcome of open reduction and internal fixation (ORIF) of acromion or spine fractures encountered before or after RSA and describes our evolution of fixation techniques.

METHODS

Between 2011 and 2023, 22 fractures or nonunions of the acromion or spine of the scapula underwent ORIF at a single institution and were followed for a minimum of 1 year. In 16 shoulders, fractures occurred after RSA, whereas 5 shoulders underwent ORIF prior to RSA. One shoulder had undergone prior failed ORIF elsewhere and revision ORIF was performed at our institution. There were 10 males and 12 females with a mean age of 67 (SD = 15.1) years. Fixation strategies included single (n = 11) and double plate fixation (n = 11). Kruskal-Wallis one-way analyses of variance were used to analyze continuous variables and Chi-square tests employed for categorical variables.

RESULTS

Of the 5 fractures treated with ORIF pre-RSA, 1 shoulder suffered an additional fracture medial to the hardware and 1 required additional bone grafting for incomplete union at the time of RSA. These 5 shoulders all underwent RSA uneventfully, but 1 fracture experienced late displacement of the scapular spine nonunion, leading to plate removal. Of the 16 post-RSA ORIF shoulders, radiographic union was confirmed in 14 and substantial residual inferior angulation identified in 3. New fractures occurred after ORIF in 5 shoulders. For patients who underwent ORIF after RSA, pain scores improved from a mean of 8 to 1.9 points, with more modest elevation gains (58.2°-91.3° pre and postoperatively, respectively).

CONCLUSIONS

ORIF of acromion and scapular spine fractures or nonunions in the setting of RSA have the potential to lead to union. When these fractures and nonunions are encountered prior to RSA, ORIF allows for uneventful RSA implantation, but secondary displacement may occur. ORIF seems to lead to improvements in pain, but more modest improvements in motion and function. Our fixation strategy has evolved to (1) dual plating, (2) spanning the whole length of the spine with 1 of the plates, (3) use of hook features under the acromion or os trigonum if possible, and (4) liberal use of bone graft.

Analysis of three different reverse shoulder arthroplasty designs for cuff tear arthropathy - the combination of lateralization and distalization provides best mobility

BACKGROUND

The two major reverse shoulder arthroplasty (RSA) designs are the Grammont design and the lateralized design. Even if the lateralized design is biomechanically favored, the classic Grammont prosthesis continues to be used. Functional and subjective patient scores as well as implant survival described in the literature so far are comparable to the lateralized design. A pure comparison of how the RSA design influences outcome in patients has not yet been determined. The aim of this study was a comparison focused on patients with cuff tear arthropathy (CTA).

METHODS

We analyzed registry data from 696 CTA patients prospectively collected between 2012 and 2020 in two specialized orthopedic centers up to 2 years post-RSA with the same follow-up time points (6,12 24 months). Complete teres minor tears were excluded. Three groups were defined: group 1 (inlay, 155° humeral inclination, 36 + 2 mm eccentric glenosphere (n = 50)), group 2 (inlay, 135° humeral inclination, 36 + 4 mm lateralized glenosphere (n = 141)) and group 3 (onlay, 145° humeral inclination, + 3 mm lateralized base plate, 36 + 2 mm eccentric glenosphere (n = 35)) We compared group differences in clinical outcomes (e.g., active and passive range of motion (ROM), abduction strength, Constant-Murley score (CS)), radiographic evaluations of prosthetic position, scapular anatomy and complications using mixed models adjusted for age and sex.

RESULTS

The final analysis included 226 patients. The overall adjusted p-value of the CS for all time-points showed no significant difference (p = 0.466). Flexion of group 3 (mean, 155° (SD 13)) was higher than flexion of group 1 (mean, 142° (SD 18) and 2 (mean, 132° (SD 18) (p < 0.001). Values for abduction of group 3 (mean, 145° (SD 23)) were bigger than those of group 1 (mean, 130° (SD 22)) and group 2 (mean, 118° (SD 25)) (p < 0.001). Mean external rotation for group 3 (mean, 41° (SD 23)) and group 2 (mean, 38° (SD 17)) was larger than external rotation of group 1 (mean, 24° (SD 16)) (p < 0.001); a greater proportion of group 2 (78%) and 3 (69%) patients reached L3 level on internal rotation compared to group 1 (44%) (p = 0.003). Prosthesis position measurements were similar, but group 3 had significantly less scapular notching (14%) versus 24% (group 2) and 50% (group 1) (p = 0.001).

CONCLUSIONS

Outcome scores of different RSA designs for CTA revealed comparable results. However, CTA patients with a lateralized and distalized RSA configuration were associated with achieving better flexion and abduction with less scapular notching. A better rotation was associated with either of the lateralized RSA designs in comparison with the classic Grammont prosthesis.

LEVEL OF EVIDENCE

Therapeutic study, Level III.

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.

Challenges for Optimization of Reverse Shoulder Arthroplasty Part II: Subacromial Space, Scapular Posture, Moment Arms and Muscle Tensioning

In part II of this comprehensive review on the optimization of reverse shoulder arthroplasty (RSA), we focus on three other challenges: 1. "Conservation of sufficient subacromial and coracohumeral space"; 2. "Scapular posture"; and 3. "Moment arms and muscle tensioning". This paper follows a detailed review of the basic science and clinical literature of the challenges in part I: 1. "External rotation and extension" and 2. "Internal rotation". "Conservation of sufficient subacromial and coracohumeral space" and "Scapular posture" may have a significant impact on the passive and active function of RSA. Understanding the implications of "Moment arms and muscle tensioning" is essential to optimize active force generation and RSA performance. An awareness and understanding of the challenges of the optimization of RSA help surgeons prevent complications and improve RSA function and raise further research questions for ongoing study.

Acromial and Scapular Spine Fractures following Reverse Total Shoulder Arthroplasty-A Systematic Review of Fixation Constructs and Techniques

Fractures of the acromion and the scapular spine are established complications of reverse shoulder arthroplasty (RSA), and when they occur, the continuous strain by the deltoid along the bony fragments makes healing difficult. Evidence on treatment specific outcomes is poor, making the definition of a gold standard fixation technique difficult. The purpose of this systematic review is to assess whether any particular fixation construct offers improved clinical and/or radiographic outcomes. A systematic review of the literature on fixation of acromial and scapular spine fractures following RSA was carried out based on the guidelines of PRISMA. The search was conducted on PubMed, Embase, OVID Medline, and CENTRAL databases with strict inclusion and exclusion criteria applied. Methodological quality assessment of each included study was done using the modified Coleman methodology score to asses MQOE. Selection of the studies, data extraction and methodological quality assessment was carried out by two of the authors independently. Only clinical studies reporting on fixation of the aforementioned fractures were considered. Fixation construct, fracture union and time to union, shoulder function and complications were investigated. Nine studies reported on fixation strategies for acromial and scapular spine fractures and were therefore included. The 18 reported results related to fractures in 17 patients; 1 was classified as a Levy Type I fracture, 10 as a Levy Type II fracture and the remaining 7 fractures were defined as Levy Type III. The most frequent fixation construct in type II scapular spine fractures was a single plate (used in 6 of the 10 cases), whereas dual platin was the most used fixation for Levy Type III fractures (5 out of 7). Radiographic union was reported in 15 out of 18 fractures, whereas 1 patient (6.7%) had a confirmed non-union of a Levy Type III scapular spine fracture, requiring revision fixation. There were 5 complications reported, with 2 patients undergoing removal of metal and 1 patient undergoing revision fixation. The Subjective Shoulder Value and Visual Analogue Scale pain score averaged 75% and 2.6 points, respectively. The absolute Constant Score and the ASES score averaged 48.2 and 78.3 points, respectively. With the available data, it is not possible to define a gold standard surgical fixation but it seems that even when fracture union can be achieved, functional outcomes are moderate and there is an increased complication rate. Future studies are required to establish a gold standard fixation technique.

Scapular spine base fracture with long outside-in superior or posterior screws with reverse shoulder arthroplasty

Background

The purpose of the present study was to determine how long superior screws alone or in combination with posterior placement of metaglene screws protruding and penetrating into the scapular spine in reverse total shoulder arthroplasty affect the strength of the scapular spine in a fresh cadaveric scapular model.

Methods

Seven fresh cadaver scapulas were allocated to the control group (short posterior and superior screws) and seven scapulars to the study group (spine base fixation with a four long screws, three with both long superior and long posterior screws).

Results

The failure load was lower in the spine fixation group (long screw, 869 N vs. short screw, 1,123 N); however, this difference did not reach statistical significance (p>0.05). All outside-in long superior or superior plus posterior screws failed due to scapular spine base fracture; failures in the short screw group were due to acromion fracture. An additional posterior outside-in screw failed to significantly decrease the failure load of the acromion spine.

Conclusions

The present study highlights the significance of preventing a cortical breach or an outside-in configuration when a superior or posterior screw is inserted into the scapular spine base.

Lateralized versus nonlateralized reverse total shoulder arthroplasty

Throughout the history of reverse total shoulder arthroplasty, the extent of lateral offset has changed considerably from "too lateral" to "too medial" and has been lately swinging back towards a point somewhere in between. Nonlateralized designs minimize shear forces on the glenoid and decrease force required by the deltoid. Glenoid lateralization decreases impingement and scapular notching and improves range of motion. Humeral lateralization achieves a more anatomic position of the tuberosities while maintaining a nonlateralized center of rotation. Several factors play a role in choosing the extent of lateral offset and method of lateralization.

An update on reverse total shoulder arthroplasty: current indications, new designs, same old problems

Reverse total shoulder arthroplasty (RTSA) was originally developed because of unsatisfactory results with anatomic shoulder arthroplasty options for the majority of degenerative shoulder conditions and fractures.

After initial concerns about RTSA longevity, indications were extended to primary osteoarthritis with glenoid deficiency, massive cuff tears in younger patients, fracture, tumour and failed anatomic total shoulder replacement.

Traditional RTSA by Grammont has undergone a number of iterations such as glenoid lateralization, reduced neck-shaft angle, modular, stemless components and onlay systems.

The incidence of complications such as dislocation, notching and acromial fractures has also evolved.

Computer navigation, 3D planning and patient-specific implantation have been in use for several years and mixed-reality guided implantation is currently being trialled.

Controversies in RTSA include lateralization, stemless humeral components, subscapularis repair and treatment of acromial fractures.

Cite this article: EFORT Open Rev 2021;6:189-201. DOI: 10.1302/2058-5241.6.200085

Simultaneous bilateral acromial base fractures after staged reverse total shoulder arthroplasty: A case report

BACKGROUND

Acromial and scapular spine fractures after reverse total shoulder arthroplasty (RTSA) are a well-known complication that may negatively impact the effects of long-term outcomes. However, to the best of our knowledge, there has been no report of simultaneous bilateral fractures of the acromion or scapular spine that occurred following staged RTSA.

CASE SUMMARY

A 79-year-old right-handed male visited our outpatient clinic with a chief complaint of pain and limited motion of both shoulder joints for a one-year duration. Based on plain radiographs and magnetic resonance images, the preoperative diagnosis was bilateral cuff tear arthropathy with failed rotator cuff repair. This patient was treated with staged bilateral RTSA at a two-month interval. At 5 and 3 mo after right and left side surgery, the patient returned to the outpatient clinic with severe pain and limited motion of both shoulder joints for 2 wk without a traumatic event. A computed tomography scan revealed non-displaced acromial base fractures of both shoulders. Considering bilateral involvement, fracture location, and patient’s demand, open reduction and internal fixation (ORIF) using plate for bilateral acromial base fractures were performed. At 2 years after ORIF, the fracture was completely healed, and the patient was satisfied with shoulder status.

CONCLUSION

This report describes an extremely rare case of simultaneous bilateral acromial base fractures after staged RTSA managed successfully by ORIF with a pre-contoured plate designed for distal clavicle fractures. Although acromial fracture after RTSA can be treated conservatively, simultaneous bilateral fractures may warrant surgical intervention as a means of addressing difficulties in activities of daily living.

The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part II

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this study was to provide a focused, updated systematic review for each of the most common complications of RSA by limiting each search to publications after 2010. In this part II, the following were examined: (1) instability, (2) humerus/glenoid fracture, (3) acromial/scapular spine fractures (AF/SSF), and (4) problems/miscellaneous.

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Overall, 137 studies for instability, 94 for humerus/glenoid fracture, 120 for AF/SSF, and 74 for problems/miscellaneous were included in each review, respectively. Univariate analysis was performed with chi-square and Fisher exact tests.

Results

The Grammont design had a higher instability rate vs. all other designs combined (4.0%, 1.3%; P < .001), and the onlay humerus design had a lower rate than the lateralized glenoid design (0.9%, 2.0%; P = .02). The rate for intraoperative humerus fracture was 1.8%; intraoperative glenoid fracture, 0.3%; postoperative humerus fracture, 1.2%; and postoperative glenoid fracture, 0.1%. The rate of AF/SSF was 2.6% (371/14235). The rate for complex regional pain syndrome was 0.4%; deltoid injury, 0.1%; hematoma, 0.3%; and heterotopic ossification, 0.8%.

Conclusions

Focused systematic reviews of recent literature with a large volume of shoulders demonstrate that using non-Grammont modern prosthesis designs, complications including instability, intraoperative humerus and glenoid fractures, and hematoma are significantly reduced compared with previous studies. As the indications continue to expand for RSA, it is imperative to accurately track the rate and types of complications in order to justify its cost and increased indications.

Periprosthetic Fractures in Reverse Total Shoulder Arthroplasty: Current Concepts and Advances in Management

PURPOSE OF REVIEW

Expanded indications for reverse total shoulder arthroplasty (RSA) have raised awareness of associated complications, including periprosthetic fractures. The purpose of this article was to provide a comprehensive update on how, when, and why RSA-related periprosthetic fractures occur, as well as to describe the current treatment strategies.

RECENT FINDINGS

Periprosthetic acromial and scapular spine fractures occur in up to 4.3% of cases and periprosthetic humeral fractures occur in approximately 3.5% of RSA procedures. Fractures of the coracoid process and clavicle have also been reported. Current literature has identified several risk factors for intraoperative or postoperative fracture, including underlying osteoporosis, revision arthroplasty, use of a superiorly placed screw during metaglene fixation, and disruption of the scapular ring by transection of the coracoacromial ligament. Periprosthetic fracture associated with RSA is a clinically significant event that warrants prolonged postoperative vigilance, timely diagnosis, and shared patient decision-making regarding treatment. Further research is needed to identify optimal treatment strategies and characterize long-term clinical outcomes following RSA-related periprosthetic fracture.

Is Acromial Fracture after Reverse Total Shoulder Arthroplasty a Negligible Complication?: A Systematic Review

Background

The purpose of this study was to investigate the incidence of acromial fracture after reverse total shoulder arthroplasty (RTSA) and clinical and radiological outcomes of treatment of the fracture.

Methods

A systematic review was performed to identify studies that reported the results of treatment of acromial fractures after RTSA. A literature search was conducted by two investigators using four databases (PubMed, Embase, Cochrane, and Ovid Medline).

Results

Fifteen studies (2,857 shoulders) satisfied our inclusion criteria. The incidence of acromial fracture after RTSA was 4.0% (114 / 2,857). The mean age of the patients at the time of fracture was 72.9 years (range, 51 to 91 years). The mean time from RTSA to diagnosis of acromial fracture was 9.4 months (range, 1 to 94 months). One hundred shoulders (87.7%) were treated conservatively and 14 shoulders (12.3%) were treated surgically. The mean follow-up period after acromial fracture was 33.8 months. The overall union rate was 50.0% (43.8% for conservative treatment and 87.5% for operative treatment). The fracture incidence was significantly different among the medial glenoid and medial humerus prosthesis design (8.4%), the lateral glenoid and medial humerus design (4.0%), and the medial glenoid and lateral humerus design (2.8%). The mean values at final follow-up were as follows: visual analog scale score, 2.2; American Shoulder and Elbow Surgeons score, 59.1; Constant score, 59.7; and Simple Shoulder Test, 5.8. The mean forward flexion, abduction, and external rotation were 102.3°, 92.3°, and 25.8°, respectively.

Conclusions

Acromial fractures after RTSA are a complication neither uncommon nor negligible. In the absence of studies with high-level evidence, there is a controversy on the outcomes after treatment. Further well-designed prospective randomized controlled studies with a long-term follow-up should be performed to ascertain the diagnosis, treatment, and prognosis of acromial fractures after RTSA.

Lateralization in reverse shoulder arthroplasty: a descriptive analysis of different implants in current practice

INTRODUCTION

Since its first description, the concept of reverse shoulder arthroplasty (RSA) has evolved. The term lateralization remains unclear and is used to describe implants that lateralize on the glenoid side, the humeral side, or both. The objective of this study was to provide a clear definition of lateralization and to measure the lateralization achieved by the most commonly used implants.

MATERIALS AND METHODS

Twenty-eight different configurations with 22 different implants were analyzed. Glenoid, humeral, and global lateralization was measured on digitized templates. Implant lateralization was normalized to the lateral offset of the Delta III. Each implant was defined as a combination of one of two glenoid categories (medialized glenoid (MG), lateralized glenoid (LG), and one of four humeral categories (medialized humerus (MH), minimally lateralized humerus (LH), lateralized humerus (LH+). In addition, implants were separated in categories of 5-mm increments for global offset (medialized RSA (M-RSA), minimally lateralized RSA (ML-RSA), lateralized RSA (L-RSA), highly lateralized RSA (HL-RSA), and very highly lateralized RSA (VHL-RSA).

RESULTS

The global lateral offset of the Delta III was 13.1 mm; global lateral offset of all designs in this study varied between 13.1 and 35.8 mm. Regarding their global lateral offset, five implants are M-RSA (lateral offset < 18.1 mm), five ML-RSA (18.1-23.1 mm), seven L-RSA (23.1-28.1 mm), six HL-RSA (28.1-33.1 mm), and one VHL-RSA (33.1-38.1 mm).

CONCLUSION

There is high variability in the amount of lateralization provided by the majority of RSAs currently available. This descriptive analysis can help surgeons understand the features of implants in the market based on their lateralization in order to adapt the surgical technique depending on the expected lateral offset of the design being implanted.

Acute Displaced Fracture of Lateral Acromion after Reverse Shoulder Arthroplasty: A Case Report and Surgical Technique

Acromial fractures are well-documented complications subsequent to reverse shoulder arthroplasty (RSA), and most appear as stress fractures with no history of single trauma. To date, no study has reported the occurrence of acute displaced acromial fracture due to sudden strong deltoid contraction during heavy work. Displacement of the fracture results in a challenging surgery since it is difficult to obtain adequate fixation in thin and osteoporotic bones. We report a rare case of acute displaced acromial fracture after successful RSA treatment, using a novel technique of open reduction and internal fixation, applying two 4.5 mm cannulated screws and lateral clavicle pre-contoured plate.

The traumatic acromion fracture: review of the literature, clinical examples and proposal of a treatment algorithm

PURPOSE

Traumatic acromion fractures are rare and typically occur in patients with multiple fractures, which often delays diagnosis. Limited guidance exists on the treatment of these fractures. We present a review of the literature from the last 20 years and describe our experience in treating five patients-two conservatively and three with open reduction and internal fixations (ORIF).

METHODS

We used the U.S. National Library of Science database, MEDLINE^®, to search for all pertinent publications from January 1999 to December 2017. Included were retrospective or prospective studies, including case series and case reports, describing treatment for traumatic acromion fractures and clinical and/or radiological outcomes. For our case reports, we present five patients with traumatic acromion fractures who were treated at our institution between 2013 and 2017.

RESULTS

Through our review of 14 publications, we found that current recommendations are often based on a limited number of cases. No gold standard to treat these fractures exists. Most authors recommend anatomic reconstruction, especially for dislocated fractures, persistent symptomatic non-unions or additional injuries to the superior shoulder suspensory complex. There is no clear trend in terms of the operative technique. With regard to our five clinical examples that were all initially treated conservatively, two were successful and three eventually required reconstruction with ORIF. Based on the findings of this review, we proposed a treatment algorithm for traumatic acromion fractures.

CONCLUSIONS

A classification system providing clear guidance on treatment options is needed. Although the non-union rate with conservative treatment is relatively high, it is not always painful or limiting to shoulder function, especially in elderly or less active patients. Fixation seems to be a more suitable treatment option for active patients who are more likely to require revision of symptomatic non-unions.