Optimizing reverse shoulder arthroplasty component position in the setting of advanced arthritis with posterior glenoid erosion: a computer-enhanced range of motion analysis

Do patient outcomes and follow-up completion rates after shoulder arthroplasty differ based on insurance payor?

BACKGROUND

Disparities associated with socioeconomic status (SES) and insurance coverage have been shown to affect outcomes in different medical conditions and surgical procedures. We hypothesized that patients insured by Medicaid will be associated with lower follow-up rates and inferior outcomes relative to those with Medicare or private insurance.

METHODS

Patients undergoing shoulder arthroplasty, including anatomic total shoulder arthroplasty, reverse arthroplasty, and hemiarthroplasty, were enrolled preoperatively in an institutional database. Preoperative demographics, payor (Medicaid, Medicare, or private insurance), and baseline American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores were recorded. Postoperatively, patients completed ASES scores at multiple time points. Follow-up completion rate was calculated as the number of follow-up visits completed relative to possible visits. Continuous variables were compared between groups with 1-way analyses of variance, and chi-squared tests were used for categorical variables. Significance was defined as P < .05.

RESULTS

There were 491 shoulder replacements performed for 438 patients from 2012-2017. The mean follow-up completed percentage was significantly lower (P < .001) for Medicaid patients (62.6% ± 33.7%) relative to Medicare patients (80.2% ± 26.7%; P < .001) and private insurance patients (77.8% ± 22.1%; P = .001). The ASES Composite score increased significantly for all patients from baseline to final follow-up. At each time point, including before surgery and each postoperative time point, patients with Medicaid insurance had significantly lower ASES Composite scores. The final ASES Composite score was significantly lower in the Medicaid patients (66.1 ± 28.7) relative to private insurance patients (78.3 ± 20.8; P = .023). Medicaid patients had significantly lower preoperative (P < .001) and postoperative (P = .018) ASES Pain subscores. In multivariate regression analysis, Medicaid insurance was associated with both inferior preoperative and postoperative ASES scores relative to patients with Medicare or private insurance.

CONCLUSIONS

We observed that all patients, regardless of insurance payor, improved by similar magnitudes after shoulder arthroplasty, though patients with Medicaid insurance had significantly lower preoperative and postoperative ASES scores, primarily because of the ASES Pain subscore. Patients with Medicaid insurance also have lower follow-up rates than other payors.

Adjusting Implant Size and Position Can Improve Internal Rotation After Reverse Total Shoulder Arthroplasty in a Three-dimensional Computational Model

BACKGROUND

Efforts during reverse total shoulder arthroplasty (RSA) have typically focused on maximizing ROM in elevation and external rotation and avoiding scapular notching. Improving internal rotation (IR) is often overlooked, despite its importance for functional outcomes in terms of patient self-care and hygiene. Although determinants of IR are multifactorial, it is unable to surpass limits of bony impingement of the implant. Identifying implant configurations that can reduce bony impingement in a computer model will help surgeons during preoperative planning and also direct implant design and clinical research going forward.

QUESTIONS/PURPOSES

In a CT-modeling study, we asked: What reverse total shoulder arthroplasty implant position improves the range of impingement free internal rotation without compromising other motions (external rotation and extension)?

METHODS

CT images stored in a deidentified teaching database from 25 consecutive patients with Walch A1 glenoids underwent three-dimensional templating for RSA. Each template used the same implant and configuration, which consisted of an onlay humeral design and a 36-mm standard glenosphere. The resulting constructs were virtually taken through ROM until bony impingement was found. Variations were made in the RSA parameters of baseplate lateralization, glenosphere size, glenosphere overhang, humeral version, and humeral neck-shaft angle. Simulated ROM was repeated after each parameter was changed individually and then again after combining multiple changes into a single configuration. The impingement-free IR was calculated and compared between groups. We also evaluated the effect on other ROM including external rotation and extension to ensure that configurations with improvements in IR were not associated with losses in other areas.

RESULTS

Combining lateralization, inferiorization, varus neck-shaft angle, increased glenosphere size, and increased humeral anteversion resulted in a greater improvement in internal rotation than any single parameter change did (median baseline IR: 85° [interquartile range 73° to 90°]; combined changes: 119° [IQR 113° to 121°], median difference: 37° [IQR 32° to 43°]; p < 0.001).

CONCLUSION

Increased glenosphere overhang, varus neck-shaft angle, and humeral anteversion improved internal rotation in a computational model, while glenoid lateralization alone did not. Combining these techniques led to the greatest improvement in IR.

CLINICAL RELEVANCE

This computer model study showed that various implant changes including inferiorization, varus neck-shaft angle, increased glenosphere size, and increased humeral anteversion can be combined to increase impingement-free IR. Surgeons can employ these currently available implant configurations to improve IR when planning and performing RSA. These findings support the need for further clinical studies validating the effect of implant configuration on resultant IR.

Effectiveness of Immersive Virtual Reality on Orthopedic Surgical Skills and Knowledge Acquisition Among Senior Surgical Residents: A Randomized Clinical Trial

IMPORTANCE

Video learning prior to surgery is common practice for trainees and surgeons, and immersive virtual reality (IVR) simulators are of increasing interest for surgical training. The training effectiveness of IVR compared with video training in complex skill acquisition should be studied.

OBJECTIVES

To evaluate whether IVR improves learning effectiveness for surgical trainees and to validate a VR rating scale through correlation to real-world performance.

DESIGN, SETTING, AND PARTICIPANTS

This block randomized, intervention-controlled clinical trial included senior (ie, postgraduate year 4 and 5) orthopedic surgery residents from multiple institutions in Canada during a single training course. An intention-to-treat analysis was performed. Data were collected from January 30 to February 1, 2020.

INTERVENTION

An IVR training platform providing a case-based module for reverse shoulder arthroplasty (RSA) for advanced rotator cuff tear arthropathy. Participants were permitted to repeat the module indefinitely.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was a validated performance metric for both the intervention and control groups (Objective Structured Assessment of Technical Skills [OSATS]). Secondary measures included transfer of training (ToT), transfer effectiveness ratio (TER), and cost-effectiveness (CER) ratios of IVR training compared with control. Additional secondary measures included IVR performance metrics measured on a novel rating scale compared with real-world performance.

RESULTS

A total of 18 senior surgical residents participated; 9 (50%) were randomized to the IVR group and 9 (50%) to the control group. Participant demographic characteristics were not different for age (mean [SD] age: IVR group, 31.1 [2.8] years; control group, 31.0 [2.7] years), gender (IVR group, 8 [89%] men; control group, 6 [67%] men), surgical experience (mean [SD] experience with RSA: IVR group, 3.3 [0.9]; control group, 3.2 [0.4]), or prior simulator use (had experience: IVR group 6 [67%]; control group, 4 [44%]). The IVR group completed training 387% faster considering a single repetition (mean [SD] time for IVR group: 4.1 [2.5] minutes; mean [SD] time for control group: 16.1 [2.6] minutes; difference, 12.0 minutes; 95% CI, 8.8-14.0 minutes; P < .001). The IVR group had significantly better mean (SD) OSATS scores than the control group (15.9 [2.5] vs 9.4 [3.2]; difference, 6.9; 95% CI, 3.3-9.7; P < .001). The IVR group also demonstrated higher mean (SD) verbal questioning scores (4.1 [1.0] vs 2.2 [1.7]; difference, 1.9; 95% CI, 0.1-3.3; P = .03). The IVR score (ie, Precision Score) had a strong correlation to real-world OSATS scores (r = 0.74) and final implant position (r = 0.73). The ToT was 59.4%, based on the OSATS score. The TER was 0.79, and the system was 34 times more cost-effective than control, based on CER.

CONCLUSIONS AND RELEVANCE

In this study, surgical training with IVR demonstrated superior learning efficiency, knowledge, and skill transfer. The TER of 0.79 substituted for 47.4 minutes of operating room time when IVR was used for 60 minutes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04404010.

The Characteristics of the Favard E4 Glenoid Morphology in Cuff Tear Arthropathy: A CT Study

Background: Cuff tear arthropathy (CTA) is characterized by superior migration of the humeral head with superior erosion of the glenoid. Rarely, humeral head migration can be anteroinferior with associated anterior erosion of the glenoid, a pattern described by Favard as the type E4 glenoid. The purpose of this retrospective imaging study was to analyze the 2D and 3D characteristics of the E4 glenoid. Methods: A shoulder arthroplasty database of 258 cuff tear arthropathies was examined to identify patients with an E4 type deformity. This resulted in a study cohort of 15 females and 2 males with an average age of 75 years. All patients had radiographs and CT scans available for analysis. CT-scan DICOM (Digital Imaging and Communications in Medicine) data were uploaded to a validated three-dimensional (3D) imaging software. Muscle fatty infiltration, glenoid measurements (anteversion, inclination), and humeral head subluxation according to the scapular plane were determined. Results: The mean anteversion and inclination of the E4 cohort were 32° ± 14° and −5° ± 2, respectively. The mean anterior subluxation was 19% ± 16%. All cases had severe grade 3 or 4 fatty infiltration of the infraspinatus, whereas only 65% had grade 3 or 4 subscapularis fatty infiltration. A significant correlation existed between glenoid anteversion and humeral head subluxation (p < 0.001), but no correlation was found with muscle fatty infiltration. The CT analysis demonstrated an acquired erosive biconcave morphology in 11 patients (65%) and monoconcavity in 6 patients (35%). Conclusion: The E4 type glenoid deformity in cuff tear arthropathy is characterized by an anterior erosion and anteversion associated with anterior subluxation of the humeral head.

A systematic review of tuberosity healing and outcomes following reverse shoulder arthroplasty for fracture according to humeral inclination of the prosthesis

BACKGROUND

Proximal humerus fractures are common in the elderly population and are often treated with reverse shoulder arthroplasty (RSA). The purpose of this systematic review was to compare tuberosity healing and functional outcomes in patients undergoing RSA with humeral inclinations of 135°, 145°, and 155°.

METHODS

A systematic review was performed of RSA for proximal humerus fracture using Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) guidelines. Radiographic and functional outcome data were extracted to evaluate tuberosity healing according to humeral inclination. Analysis was also performed of healed vs. nonhealed tuberosities.

RESULTS

A total of 873 patients in 21 studies were included in the analysis. The mean age was 77.5 years (range of 58-97) and the mean follow-up was 26.2 months. Tuberosity healing was 83% in the 135° group compared with 69% in the 145° group and 66% in the 155° group (P = .030). Postoperative abduction was highest in the 155° group (P < .001). No significant difference was found in forward flexion, external rotation, or postoperative Constant score between groups. Patients with tuberosity healing demonstrated 18° higher forward flexion (P = .008) and 16° greater external rotation (P < .001) than those with unhealed tuberosities.

CONCLUSION

RSA for fracture with 135° humeral inclination is associated with higher tuberosity healing rates compared with 145° or 155°. Postoperative abduction is highest with a 155° implant, but there is no difference in in postoperative forward flexion, external rotation, or Constant score according to humeral inclination. Patients with healed tuberosities have superior postoperative forward flexion and external rotation than those with unhealed tuberosities.

Do Preoperative and Postoperative Glenoid Retroversion Influence Outcomes After Reverse Total Shoulder Arthroplasty?

Background

There are limited data on the effect of glenoid retroversion in clinical outcomes following reverse total shoulder arthroplasty (RTSA). The purpose of this study was to evaluate if surgical correction of retroversion affects outcomes following RTSA.

Methods

An institutional database was utilized to identify 177 patients (mean age: 68.2 ± 10.1 years) with minimum 2-year follow-up after primary RTSA. Glenoid version was measured on preoperative and postoperative radiographs. American Shoulder and Elbow Surgeons (ASES) scores and range of motion were collected before and after RTSA. Change in retroversion was determined by comparing preoperative and postoperative glenoid retroversion on radiographs using paired Wilcoxon signed-rank test. Spearman’s rank correlation was used to investigate relationships between ASES scores and glenoid retroversion.

Results

The mean postoperative ASES composite score (75.5 ± 22.7) was significantly higher than preoperative (36.8 ± 19.2; P < .0001). The mean preoperative glenoid retroversion was 9.1 ± 6.7° compared to 6.5 ± 5.1° postoperatively (P < .0001). There was no correlation between postoperative ASES scores and preoperative retroversion (r = .014, P = .85) or postoperative retroversion (r = −.043, P = .57). There was no statistical relationship between postoperative retroversion and range of motion, though there is a risk of inadequate power given the sample size.

Conclusions

Patient-reported outcomes and range of motion measurements following RTSA at short-term follow-up appear to be independent of either preoperative or postoperative glenoid retroversion.

Development and Application of a Novel Metric to Characterize Comprehensive Range of Motion of Reverse Total Shoulder Arthroplasty

Active range of motion (ROM) of reverse total shoulder arthroplasty (rTSA) can be limited by bony impingement, muscle inability, and joint instability. The aim of this study was to develop a novel metric representative of comprehensive ROM of rTSA, which is evaluated in the context of all three factors. It was hypothesized that the metric, termed global circumduction ROM (GC-ROM), would capture differences resulting from directional changes in rTSA design parameters known to increase ROM. GC-ROM was calculated for a set of 18 rTSA configurations with humeral polyethylene cup depths of 6 and 8.1 mm, glenosphere lateralization (GLat) distances of 0, 5, and 10 mm, and neck-shaft angles (NSA) of 135°, 145°, and 155°. For any implant configuration, arm positions were defined by internal/external (IE) rotation angle and two spherical coordinates representing the elevation plane angle and elevation angle. At each IE rotation angle, incremental positions with variable elevation plane and elevation angles were checked for feasibility based on impingement, muscle ability, and risk of instability. Coordinates of feasible positions were mapped to unit spheres and connected to form regions, of which the surface area was calculated to represent allowable circumduction ROM. ROMs were averaged across all IE rotation angles to produce a single metric, GC-ROM. The results showed that decreasing cup depth and increasing GLat and NSA increased GC-ROM. In conclusion, a novel metric to characterize comprehensive ROM, evaluated based on several ROM-limiting factors, was developed as a performance metric through which rTSA designs can be compared. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:880-887, 2020.

Effect of humeral stem and glenosphere designs on range of motion and muscle length in reverse shoulder arthroplasty

PURPOSE

To determine how different combinations of humeral stem and glenosphere designs for reverse shoulder arthroplasty (RSA) influence range of motion (ROM) and muscle elongation.

METHODS

A computed tomography scan of a non-pathologic shoulder was used to simulate all shoulder motions, and thereby compare the ROM and rotator cuff muscle lengths of the native shoulder versus 30 combinations of humeral components (1 inlay straight stem with 155° inclination and five onlay curved stems with 135°, 145° or 155° inclinations, using concentric, medialized or lateralized trays) and glenospheres (standard, large, lateralized, inferior eccentric and bony increased-offset (BIO-RSA)).

RESULTS

Only five of the 30 combinations restored ≥ 50% of the native ROM in all directions: the 145° onlay stem (concentric tray) combined with lateralized or inferior eccentric glenospheres and the 145° stem (lateralized tray) combined with either a large, lateralized or inferior eccentric glenosphere. Lengthening of the supraspinatus and infraspinatus, observed for all configurations, was greatest using onlay stems (7-30%) and BIO-RSA glenospheres (13-31%). Subscapularis lengthening was observed for onlay stems combined with BIO-RSA glenospheres (5-9%), while excessive subscapularis shortening was observed for the inlay stem combined with all glenospheres except the BIO-RSA design (> 15%).

CONCLUSIONS

The authors suggest implanting 145° onlay stems, with concentric or lateralized trays, together with lateralized or inferior eccentric glenospheres.

A randomized single-blinded trial of early rehabilitation versus immobilization after reverse total shoulder arthroplasty

BACKGROUND

Reverse total shoulder arthroplasty (RTSA) does not have a standard postoperative protocol. Although instability is a worrisome complication, prolonged immobilization may also be disabling in the elderly population. This study aimed to determine if early vs. delayed range of motion (ROM) after RTSA affected postoperative ROM, patient-reported outcomes, and the dislocation rate.

METHODS

A single-blinded, randomized controlled trial was performed enrolling patients from 2013 to 2017. Patients were randomly assigned to either a delayed-rehabilitation group (no ROM for 6 weeks) or early-rehabilitation group (immediate physical therapy for passive and active ROM) and followed up for a minimum of 1 year. Demographic characteristics, ROM, American Shoulder and Elbow Surgeons (ASES) scores, and complications were recorded.

RESULTS

Of an initial enrollment of 107 shoulders, 80.3% completed 1-year follow-up: 44 shoulders in the delayed-therapy group and 42 shoulders in the immediate-therapy group. Both groups had significantly improved forward flexion (32° improvement) and abduction (22° improvement) by 3 months. Both groups showed significant improvements in ASES scores by 6 weeks (9.4-point improvement in composite score) with continued improvement through 6 months (35.1 points). No significant differences were found between groups for any postoperative measure, with the exception of the ASES functional score favoring the delayed-therapy group at 6 months (26.3-point improvement vs. 16.7-point improvement). No differences in complications, notching, or narcotic use were noted between groups.

CONCLUSIONS

Both early- and delayed-ROM protocols after RTSA demonstrated significant, similar improvements in ROM and outcomes. Early initiation of postoperative rehabilitation may benefit the elderly population by avoiding the limitations of prolonged immobilization postoperatively.

Toileting ability of patients after primary reverse total shoulder arthroplasty

Background

This study aimed to determine the toileting ability (TA) of patients undergoing primary reverse total shoulder arthroplasty (RTSA) and identify factors associated with TA postoperatively.

Methods

A questionnaire regarding toileting was administered to 119 patients who underwent primary RTSA with a minimum 1-year follow-up. Patients were separated into 2 groups based on whether the arm that underwent RTSA was the one used for toileting (study group, n = 74) or not (control group, n = 45). Patient-reported TA was calculated both before and after RTSA. Multivariate analysis was performed to identify factors associated with TA postoperatively.

Results

Impairment in TA before RTSA was higher in the study group and affected almost three-quarters of the patients (72%). In the study group, primary RTSA resulted in a statistically significant improvement in TA (P < .001), and no difference in TA was found between groups after RTSA (P = .076). Postoperatively, 92% of the patients in the study group were able to manage toileting with the involved extremity (54% without difficulty and 38% with some degree of difficulty). Only 1 patient (1.3%) was totally unable to manage toileting with either arm postoperatively. The patients at risk of toileting difficulties postoperatively were those who had preoperative toileting difficulties and lower postoperative internal rotation range of motion.

Conclusions

Over 90% of patients can manage toileting after primary RTSA, and total toileting inability is rare after the procedure (1.3%). Patients should be counseled that after primary RTSA, they have a high probability of being able to manage toileting with independence even if it is with some difficulty.

Management of the B2 Glenoid in Glenohumeral Osteoarthritis

The Walch B2 glenoid is characterized by a biconcave glenoid deformity, acquired glenoid retroversion, and posterior humeral head subluxation. Surgical reconstruction of the B2 glenoid remains a challenge. Surgical management options include arthroscopic debridement, hemiarthroplasty, anatomic total shoulder arthroplasty with eccentric reaming, bone grafting or augmented glenoid implants, and reverse total shoulder arthroplasty. Multiple factors dictate the optimal surgical management strategy.. This article describes each of these techniques and presents the current available literature in an effort to guide evidence-based decisions in the surgical management of the B2 glenoid deformity.

Autografting for B2 Glenoids

The Walch B2 glenoid is characterized by a biconcave glenoid deformity, acquired glenoid retroversion, and posterior subluxation of the humeral head. Surgical reconstruction of the B2 glenoid is often challenging due to the complexity of the deformity. Bone graft augmentation using humeral head autograft is a valuable adjunct to anatomic total shoulder arthroplasty in the B2 glenoid, particularly in the young, highly active patient with severe glenoid retroversion (>25°–30°). Although this technique affords the ability to correct glenoid version and simultaneously enhances glenoid bone stock, it is technically challenging. The potential for graft-related complications also exists, which may further impact glenoid implant longevity and functional outcome. This review article aims to describe the B2 glenoid morphology, discuss the challenges in managing the B2 deformity, and provide further insight specifically regarding autografting at the time of anatomic total shoulder arthroplasty for reconstruction of the B2 glenoid.

Three-dimensional characterization of the anteverted glenoid (type D) in primary glenohumeral osteoarthritis

BACKGROUND

The Walch classification describes glenoid morphology in primary arthritis. As knowledge grows, several modifications to the classification have been proposed. The type D, a recent modification, was defined as an anteverted glenoid with or without anterior subluxation. Literature on the anteverted glenoid in primary osteoarthritis is limited. The purpose of this study, therefore, was to analyze the anatomic characteristics of the type D glenoid on radiographs and computed tomography (CT).

METHODS

The shoulder arthroplasty databases from 3 institutions were examined to identify patients with primary glenohumeral osteoarthritis and glenoid anteversion (≥5°), with or without anterior subluxation. The type D study cohort consisted of 18 patients (3% of the osteoarthritis cohort) and was a mean of 70 years old, with 11 women and 7 men. All radiographs were reviewed, and computed tomography Digital Imaging and Communications in Medicine (National Electrical Manufacturers Association, Rosslyn, VA, USA) data were analyzed on validated 3-dimensional imaging software. Rotator cuff fatty infiltration, glenoid measurements (anteversion and inclination), and humeral head subluxation according to the scapular plane were determined.

RESULTS

In the study cohort, the mean glenoid anteversion was 12° (range, 5°-24°), the mean inclination was 0°, and the mean anterior subluxation was 38% (range, 6%-56%). Eight patients (44%) had a biconcave glenoid with a posterosuperiorly positioned paleoglenoid and an anteroinferiorly positioned neoglenoid, and 10 patients had a monoconcave glenoid. Fatty infiltration of the rotator cuff muscles never exceeded Goutallier stage 2.

CONCLUSION

The type D glenoid is an addition to the original Walch classification and is characterized by glenoid anteversion (≥5°), anteroinferior humeral head subluxation, and absence of severe subscapularis fatty infiltration.