Medialized Versus Lateralized Center of Rotation in Reverse Shoulder Arthroplasty

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.

Latissimus Dorsi and Teres major tendon transfer increases internal rotation torque following lateralized reverse shoulder arthroplasty with subscapularis insufficiency

INTRODUCTION

Limitation of active Internal Rotation (IR) following Reverse Shoulder Arthroplasty (RSA) in patients with massive Rotator Cuff Tears (mRCTs) with subscapularis insufficiency remains a challenge. Recently, RSA with Latissimus dorsi and Teres major (LDTM) transfer in patients with limited active IR has been demonstrated as a reliable treatment option. The purpose of this study was to biomechanically compare the IR torque following LDTM transfer with RSA in mRCT with subscapularis insufficiency to RSA without tendon transfer.

METHODS

Eight cadaveric shoulders were tested (mean age: 64.5 ± 1.9 years) using a custom shoulder testing system that permits loading conditions of mRCT with subscapularis insufficiency. Two conditions were tested and compared. The first condition was RSA alone and the second condition was RSA with LDTM transfer. RSA with a medialized glenoid and lateralized humerus design was used for all specimens. The specimens were tested at 0°, 20° and 40° abduction at three different muscle loads: baseline, double, and triple, while the Teres minor and deltoid loads were kept constant. IR torque was measured with a torque wrench at 0°, 20°, and 40° abduction and 60° and 45° IR positions. Force required for anterior dislocation was measured at 20° abduction and 10° IR position.

RESULTS

RSA with LDTM transfer had significantly higher IR torque at all abductions and muscle loading compared with RSA without transfer (average at all positions; RSA without transfer: 0.80 ± 0.02 Nm, LDTM transfer for all loads: 1.43 ± 0.10 Nm). RSA with LDTM transfer (91.4 ± 3.9 N) needed higher force for anterior dislocation compared to RSA alone (89.4 ± 4.1 N), but there was no significant difference.

CONCLUSION

LDTM transfer with RSA increases IR torque compared to RSA without tendon transfer in a cadaveric model. LDTM transfer with RSA may be a reliable treatment option for patients with mRCT and subscapularis insufficiency who are expected to have limited active IR following RSA.

Outcomes of Reverse Total Shoulder Arthroplasty with Latissimus Dorsi Tendon Transfer for External Rotation Deficit: A Systematic Review and Meta-Analysis

BACKGROUND

Latissimus dorsi transfer (LDT) has been purported to restore motion in patients undergoing reverse shoulder arthroplasty (RSA) who have preoperative combined loss of forward elevation (FE) and external rotation (ER). This systematic review summarizes the available evidence for the functional outcomes and complications after RSA with LDT. Furthermore, the effect of implant design and whether a concomitant teres major transfer (TMT) was performed were studied.

METHODS

A systematic review was performed per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We queried PubMed/MEDLINE, Embase, Web of Science, and Cochrane databases to identify articles reporting on LDT with RSA to restore ER. Our primary outcomes were ER, FE, Constant score, and complication incidence. Secondarily, we reported postoperative internal rotation (IR) and compared ER, FE, and Constant score based on lateralized versus medialized global implant design and whether concomitant TMT was performed.

RESULTS

Nineteen studies were evaluated; functional outcomes were assessed in 16 articles reporting on 258 RSAs (123 LDT, 135 LDT-TMT). Surgical indication was most commonly cuff tear arthropathy and massive irreparable cuff tear. Mean ER was -12° preoperatively and 25° postoperatively, FE was 72° preoperatively and 141° postoperatively. Mean postoperative Constant score was 65. Of 138 patients (8 studies) describing IR, only 25% reported a mean postoperative IR ≥L3. Subanalysis comparing lateralized versus medialized implants and whether TMT was concomitantly performed demonstrated no significant difference in postoperative ER, FE, and Constant score, nor preoperative to postoperative improvement in ER and FE. The complication rate was 14.1% (of 291 shoulders from 16 studies), including tear in the tendon transfer (n = 3), revision tendon repair (n = 1), nerve-related complication (n = 9), and dislocation (n = 9).

CONCLUSIONS

RSA with LDT is a reliable option to restore motion, with a comparable complication rate with standard RSA. The use of medialized versus lateralized implants and whether the TM was concomitantly transferred may not influence clinical outcomes.

LEVEL OF EVIDENCE

Level IV. See Instructions for Authors for a complete description of levels of evidence.

Mid-term comparative study between the glenoid and humerus lateralization designs for reverse total shoulder arthroplasty: which lateralization design is better?

INTRODUCTION

The complications of the conventional medialized design for reverse total shoulder arthroplasty (RSA) are increased scapular notching, and decreased external rotation and deltoid wrapping. Currently, lateralization design RSA, which avoid scapular notching and improve impingement-free range of motion, is commonly used. Especially, humeral lateralization design was most commonly used and glenoid lateralization design was preferred for glenoid abnormities. We compared mid-term clinical and radiologic outcomes of glenoid and humeral lateralization RSA in an Asian population in this study.

MATERIALS AND METHODS

We enrolled 124 shoulders of 122 consecutive patients (mean age 73.8 ± 6.8 years) who received glenoid or humeral lateralization RSA from May, 2012 to March, 2019. We divided these patients into two groups according to RSA using either glenoid or humeral lateralization design. These different designs were introduced consecutively in Korea. The clinical and radiological results of 60 glenoid lateralization RSA (Group I, 60 patients) and 64 humeral lateralization RSA (Group II, 62 patients) were retrospectively evaluated and also were compared between the two groups. All patients were followed for mean 3 years.

RESULTS

The clinical and radiologic outcomes of the two groups did not differ significantly, including scapular notching (p = 0.134). However, humeral lateralization RSA showed a larger glenoid-tuberosity (GT) distance (p = 0.000) and less distalization shoulder angle (DSA) (p = 0.035). The complication rate did not differ significantly either. But, revision surgery was performed for 2 humeral loosening in the Group II.

CONCLUSION

The clinical and radiologic outcomes of the two groups did not differ significantly, including scapular notching at mid-term follow-up. However, humeral lateralization design showed larger GT distance and less DSA. Humeral lateralization design RSA could preserve the normal shoulder contour due to a larger GT distance (more lateralization) and provide less deltoid tension due to less DSA (less distalization of COR).

Comparison of Clinical Performance of Inlay versus Onlay Humerus Implants in Reverse Total Shoulder Arthroplasty

Background

Reverse total shoulder arthroplasty (RTSA) has become the treatment of choice for the management of massive rotator cuff tears combined with cuff tear arthropathy, and many novel designs have been proposed to overcome the shortcomings of classic RTSA. This study sought to evaluate and compare RTSA outcomes among patients with cuff tear arthropathy treated by a medialized inlay humerus implant with a neck shaft angle of 155° or a lateralized onlay implant with a neck shaft angle of 145°.

Methods

A retrospective review of 32 inlay implants and 32 onlay implants was performed. The active range of motion (ROM), visual analog scale (VAS) for pain, motor power for elevation and external rotation, and functional scores including the American Shoulder and Elbow Surgeons score, Constant score, and Korean Shoulder Scoring system were assessed before surgery, at 3, 6, and 12 months after surgery, and at the last follow-up at least 24 months after surgery. Scapular notching, lateral humeral offset, and deltoid wrapping offset were assessed for radiographic evaluation.

Results

The preoperative demographic data of both groups showed no significant differences (p > 0.05). The mean follow-up period was 24.9 months. Significant improvements in forward flexion, functional scores, and pain VAS score were observed in both groups at the last follow-up. No significant differences in ROM or functional scores were found between two groups at each time point, except that the onlay implant group exhibited a significantly greater range of external rotation at 3 and 12 months after surgery and at the last follow-up. The rate of scapular notching and the final power improvement did not show significant differences between the groups.

Conclusions

Primary RTSA using inlay or onlay humerus implants was associated with recovery from pseudoparalysis and good clinical outcomes. However, RTSA with onlay humerus implantation led to clinically superior results in terms of external rotation.

Can surgeons optimize range of motion and reduce scapulohumeral impingements in reverse shoulder arthroplasty? A computational study

BACKGROUND

Early glenohumeral impingement leads to poor range of motion and notching in reverse shoulder arthroplasty. The aim was to find from planning software which implant configuration provides the best motions in reverse shoulder arthroplasty.

PATIENTS AND METHODS

Reverse shoulder arthroplasty planning (Glenosys) was made in 31 patients (12 men, 19 women, 76 ± 6 yo) and impingements were analyzed. Inlay (155°-inclined) and Onlay (145°-inclined) humeral designs were tested. Four configurations were tested for each shoulder: "INLAY": non-lateralized glenoid-inlay humerus, "BIO-INLAY": lateralized glenoid (BIO-RSA)-inlay humerus, "ONLAY": non-lateralized glenoid-onlay humerus, and "BIO-ONLAY": lateralized (BIO-RSA) glenoid-onlay humerus.

RESULTS

BIO-ONLAY and BIO-INLAY groups presented a significantly better result in all tested motion (p < 0.001 for all tests). BIO-ONLAY allowed a significantly better external rotation, extension and adduction than BIO-INLAY with decreased impingements with the pilar. BIO-INLAY presented a significantly better abduction. In abduction, an abutment of the greater tuberosity against the acromion was associated with a lower range of motion (p < 0.0001) and did not depend on the lateralization.

CONCLUSION

Glenoid lateralization delays the glenohumeral impingement in reverse shoulder arthroplasty and gives the best rotations, adduction and extension when associated with neutral inclination and humeral 145° inclination. Greater tuberosity abutment has to be avoided in abduction and the Inlay design provides the best abduction.

The Role of Humeral Neck-Shaft Angle in Reverse Total Shoulder Arthroplasty: 155° versus <155°—A Systematic Review

The aim of this study was to have updated scrutiny of the influence of the humeral neck-shaft angle (HNSA) in patients who underwent reverse shoulder arthroplasty (RSA). A PRISMA-guided literature search was conducted from May to September 2021. Clinical outcome scores, functional parameters, and any complications were reviewed. Eleven papers were identified for inclusion in this systematic review. A total of 971 shoulders were evaluated at a minimum-follow up of 12 months, and a maximum of 120 months. The sample size for the "HNSA 155°" group is 449 patients, the "HNSA 145°" group involves 140 patients, and the "HSNA 135°" group comprises 291 patients. The HNSA represents an important variable in choosing the RSA implant design for patients with rotator cuff arthropathy. Positive outcomes are described for all the 155°, 145°, and 135° HSNA groups. Among the different implant designs, the 155° group show a better SST score, but also the highest rate of revisions and scapular notching; the 145° cohort achieve the best values in terms of active forward flexion, abduction, ASES score, and CMS, but also the highest rate of infections; while the 135° design obtains the best results in the external rotation with arm at side, but also the highest rate of fractures. High-quality studies are required to obtain valid results regarding the best prosthesis implant.

Restoration of active internal rotation following reverse shoulder arthroplasty: anterior latissimus dorsi and teres major combined transfer

BACKGROUND

Reverse shoulder arthroplasty (RSA) for irreparable massive rotator cuff tear (mRCT) and cuff tear arthropathy (CTA) demonstrates satisfactory clinical outcomes. However, many studies have reported no significant improvements in internal and external rotation. To our knowledge, there have been no studies on new attempts to restore active internal rotation following RSA. The purpose of this study was to compare RSA alone and RSA with anterior latissimus dorsi and teres major (aLDTM) tendon transfer in patients with CTA and mRCT with combined loss of active elevation and internal rotation (CLEIR).

METHODS

This retrospective cohort study included patients who underwent RSA with a lateralized design and had CLEIR between October 2014 and January 2019. Two groups were classified: patients who underwent RSA alone (group R, n = 36) and patients who underwent RSA with aLDTM tendon transfer (group T, n = 24). Clinical outcomes, including the visual analog scale score, Constant score, American Shoulder and Elbow Surgeons score, active range of motion, score for activities of daily living requiring active internal rotation (ADLIR), and ability to perform toileting activity, were compared. Moreover, radiologic outcomes and complications were compared.

RESULTS

The mean follow-up period was 36.8 ± 11.6 months (range, 24-67 months). Both group R and group T showed significant improvements in clinical scores and active range of motion preoperatively and postoperatively. In group T, the Constant score (65.2 ± 7.5 vs. 58.1 ± 12.3, P = .008), ADLIR score (26.1 ± 3.1 vs. 20.3 ± 5.0, P < .001), internal rotation level with the arm behind the back (P < .001), and subscapularis-specific physical examination findings (P < .001) were significantly better than in group R. However, no significant difference in the American Shoulder and Elbow Surgeons score, forward flexion, and external rotation at 0° and 90° of abduction were found at final follow-up. Transient axillary nerve palsy was found in 2 patients in group T. However, there were no significant differences in complication rates between 2 groups.

CONCLUSION

Lateralized RSA with aLDTM tendon transfer for patients with CTA and mRCT with CLEIR restored shoulder function and improved clinical outcomes, especially the ability to perform ADLIR and toileting activity.

Three-dimensional kinematic evaluation of scapulohumeral rhythm after reverse shoulder arthroplasty: a systematic review and meta-analysis

Background

The movement of the arm relative to the trunk results from 3-dimensional (3D) coordinated movements of the glenohumeral (GH) and scapulothoracic (ST) joints and dictates the scapulohumeral rhythm (SHR). Alterations in SHR increase joint overload and may lead to low functional scores, pain, and failures in patients undergoing reverse total shoulder arthroplasty (RSA). The goal of this systematic review and meta-analysis was to examine 3D SHR kinematics after RSA and compare it to that of asymptomatic shoulders.

Methods

A systematic review and meta-analysis of articles in English were performed using PubMed, Embase, Cochrane Library, and SciELO. Additional studies were identified by searching bibliographies. Search terms included "Reverse shoulder arthroplasty", "3D", and "scapula". It was selected cross-sectional studies that reported SHR with 3D motion analysis systems in patients who underwent RSA and asymptomatic controls. Two authors independently performed the extraction of articles using predefined data fields, including study quality indicators.

Results

Data from four studies were included in quantitative analysis, totaling 48 shoulders with RSA and 63 asymptomatic shoulders. Pooled analyses were based on random-effects model (DerSimonian-Laird). A statistically smaller SHR ratio was observed in the RSA group than that in the control group (P < .00001), meaning a greater contribution of ST joint in relation to GH joint for arm elevation. The standardized mean difference was -1.16 (95% confidence interval: -1.64, -0.67). A sensitivity analysis with three more studies that had imputed data on control group did not change the direction of the effect. The standardized mean difference on sensitivity analysis was -0.60 (P = .03; 95% confidence interval: -1.13, -0.06). It was detected as "not important heterogeneity" within the comparison (I2: 22%). Chi-square was not statistically significant (Chi2: 3.85), and I2 was 22%. Tau2 was not zero (Tau2: 0.05). Sensitivity analysis showed an I2 of 74%, which might represent substantial heterogeneity, Chi-square was not statistically significant (Chi2: 23.01), and Tau2 was not zero (Tau2: 0.37).

Conclusion

This study found that RSA shoulders have an increased contribution of ST joint during arm elevation, compared with asymptomatic shoulders. More movement in ST joint in proportion to GH joint increases GH joint contact forces, which could lead to component loosening or other complications. Further studies should address the clinical implications of this kinematic finding.

Lateralized vs. classic Grammont-style reverse shoulder arthroplasty for cuff deficiency Hamada stage 1-3: does the design make a difference?

BACKGROUND

Reverse shoulder arthroplasty (RSA) with a lateralized design is thought to improve outcomes. Our aim was to compare RSA with the classic Grammont prosthesis against a prosthesis with 135° inclination and a lateralized glenosphere for cuff-deficient shoulders.

METHODS

Patients with irreparable massive posterosuperior rotator cuff tear Hamada grade 1-3 underwent RSA and were documented prospectively up to 24 months postsurgery. Comparative RSA groups were "lateralized" (L), with 135° humeral inclination and 36+4-mm lateralized glenosphere (n = 44), and "Grammont" (G), with 155° humeral inclination and 36+2-mm eccentric glenosphere (n = 23). Range of motion including the Apley scratch test, abduction strength, Constant-Murley score (CS), and Shoulder Pain and Disability Index (SPADI) were assessed. Anteroposterior and axial radiographs were evaluated at 24 months, and additional measurements of scapular neck and glenoid anatomy, baseplate and glenosphere position, center of rotation, humeral offset, and lateralization and distalization shoulder angles were made. Linear regression and mixed models adjusted for sex differences and preoperative values were applied.

RESULTS

Overall CS and SPADI outcomes were not significantly different between groups (P ≥ .654). For group L, external rotation remained stable up to the 2-year follow-up and was higher than for group G (P = .012 ); a greater proportion of group L patients could reach the lumbar vertebra 3 (L3) (70% vs. 48% in group G) (P = .26). Group G had a higher inferior glenosphere overhang (P = .020) and center of rotation (COR) medialization (P < .001), whereas group L had higher humeral offset (P < .001) and lateralization shoulder angle (P < .001) with a trend toward higher baseplate positioning (P = .045). The rate of scapular notching was 2.9 times higher for group G than group L (P = .001).

CONCLUSION

RSA with 135° humeral inclination and a lateralized glenosphere shows similar outcome scores as the classic Grammont design but enables better preservation of external rotation and reduces the rate of scapular notching compared with the classic Grammont design in Hamada 1-3 patients with irreparable posterosuperior tears.

Factors affecting internal rotation after reverse shoulder arthroplasty

BACKGROUND

The limitation or loss of internal rotation (IR) after the surgery is a major problem in reverse shoulder arthroplasty (RSA). The particular factors associated with postoperative IR remain unclear. We aimed to analyze the predictors of IR after RSA.

METHODS

We included primary RSA patients with the following implants and a minimum of 1-year follow-up: Wright Aequalis (n = 25), DJO Encore (n = 29), Biomet Comprehensive (n = 40), and Exactech Equinoxe (n = 29). Age, sex, dominant hand, primary diagnosis, implant type, preoperative critical shoulder angle, pre- and postoperative acromiohumeral distance, lateral offset of implant, glenosphere inclination, peg-glenoid rim distance (PGRD), glenosphere overhang, scapular notching, subscapularis (SSc) repair, pre- and postoperative ROM, and functional scores were assessed. IR was assessed using a 10-point scale based on the following anatomical levels: from the greater trochanter to the buttocks (2 points), from the sacrum to L4 (4 points), from L3 to L1 (6 points), from T12 to T8 (8 points), and from T7 to T1 (10 points). Univariable and multivariable analyses were performed to identify the factors affecting the IR after RSA.

RESULTS

One hundred twenty-three shoulders (123 patients) with a mean follow-up of 30.59 ± 19.55 (range, 12-83) months were evaluated. In the univariable analysis, preoperative diagnosis [odds ratio (OR) = 0.243, P = 0.001], implant type (P = 0.002), PGRD (OR = 1.187, P = 0.003), and preoperative IR (P < 0.001) were found to be factors associated with postoperative IR. Preoperative IR was the only factor associated with postoperative IR in the multivariable analysis (P < 0.001). Patients with preoperative IR scores of 10 or 8 points showed significantly better IR after RSA than those with preoperative IR scores of 2 or 4 points (10 points vs. 2 or 4 points; OR = 15.433, P = 0.002, 8 points vs. 2 or 4 points; OR = 6.078, P < 0.001).

CONCLUSION

Preoperative IR was the only independent factor for IR after RSA. Patients with excellent preoperative IR had better postoperative IR than those with poor preoperative IR. Preoperative diagnosis, implant type, SSc repair, implant lateralization, glenosphere inferior placement, and scapular notching were not identified as independent predictors of IR after RSA in our sample size.

Medialized versus Lateralized Center of Rotation in Reverse Total Shoulder Arthroplasty: A Systematic Review and Meta-Analysis

One of the original biomechanical principles of reverse total shoulder arthroplasty (RTSA) is medialization of the center of rotation (COR) relative to the native level of the glenoid. Several authors have proposed the lateralized center of rotation, which is characterized by a lateralized (L) glenoid and medialized (M) humeral component. The aim of this review is to compare the clinical and functional outcomes of COR in medialized (M-RTSA) and lateralized (L-RTSA) RTSA in patients with uniform indications and treatment through a meta-analysis. A PRISMA-guided literature search of PubMed, Medline, Embase, Scopus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Cochrane Clinical Answers was conducted from April to May 2021. Twenty-four studies were included in the qualitative synthesis, and 19 studies were included in the meta-analysis. Treatment with RTSA resulted in positive post-operative outcomes and low complication rates for both groups. Statistically relevant differences between L-RTSA group and M-RTSA group were found in post-operative improvement in external rotation with arm-at-side (20.4° and 8.3°, respectively), scapular notching rates (6.6% and 47.7%) and post-operative infection rates (1% and 7.7%). Both lateralized and medialized designs were shown to improve the postoperative outcomes. Nevertheless, a lateralized COR resulted in greater post-operative external rotation.

Early restoration of shoulder function in patients with the Grammont prosthesis compared to lateralized humeral design in reverse shoulder arthroplasty

BACKGROUND

This study aimed to compare the clinical outcomes and radiographic parameters of patients after reverse shoulder arthroplasty (RSA) between the Grammont prosthesis and lateralized humeral design prosthesis.

METHODS

A total of 114 patients who underwent RSA with a lateralized humeral design (group L; 71 shoulders) and medialized humeral design (group M; 43 shoulders) prosthesis for cuff tear arthropathy or irreparable rotator cuff tear were enrolled. Clinical outcomes including visual analog scale (VAS), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Constant scores and range of motion (ROM) were serially followed up at postoperative 3, 6, 12, and 24 months. Radiographic parameters were measured to evaluate preoperative and postoperative status.

RESULTS

Both prostheses demonstrated similar clinical outcomes and shoulder function preoperatively and at postoperative 2 years (P >.05). However, patients in group M had significantly better postoperative active forward flexion (postoperative 3 months, 115° ± 12° vs. 101° ± 14°; P <.001; 6 months, 125° ± 13° vs. 118° ± 13°; P <.013) and abduction (3 months, 105° ± 12° vs. 98° ± 12°; P = .002); VAS (3 months, 3.1 ± 1.2 vs. 3.7 ± 1.4; P = .031; 6 months, 2.3 ± 1.1 vs. 2.8 ± 1.3; P = .038); ASES (3 months, 64.2 ± 7.0 vs. 60.4 ± 9.2; P = .022; 6 months, 70.6 ± 6.0 vs. 66.6 ± 8.1; P = .007); and Constant scores (6 months, 59.6 ± 6.9 vs. 55.7 ± 9.3; P = .020). Group L showed a significantly lower rate of scapular notching than group M (15.5% vs. 41.8%; P < .001). The position of the proximal humerus in group L was more lateralized and less distalized than in group M after RSA.

CONCLUSIONS

RSA with both the Grammont and lateralized humeral design prostheses provided similar shoulder ROM restoration and functional improvements at a minimum of 2 years. However, patients with a humeral lateralized prosthesis showed slower recovery of shoulder function and ROM up to postoperative 6 months despite a lower incidence of scapular notching.

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.

Lateralized versus nonlateralized glenospheres in reverse shoulder arthroplasty: a systematic review with meta-analysis

HYPOTHESIS/BACKGROUND

Lateralization in reverse shoulder arthroplasty (L-RSA) was proposed to overcome some limitations of the original Grammont-style design (S-RSA). This systematic review aims to compare the clinical and functional outcomes and complications of S-RSA with L-RSA, and to assess the individual results of metallic and bony lateralization implants.

METHODS

A systematic search from January 1980 to December 2019 was performed. Studies were selected in 2 phases by 2 independent reviewers; disagreements were solved by discussion. Inclusion criteria were: (1) original studies; (2) written in English or French; (3) adult individuals submitted to RSA surgery; and (4) RSA with a lateralization device in at least one of the groups. Exclusion criteria were: (1) nonoriginal studies or case reports; (2) absence of clinical or radiographic outcomes; and (3) no comparison group using S-RSA. Data were extracted for outcomes of functional status (American Shoulder and Elbow Surgeons, Constant, visual analog scale, Simple Shoulder Test, Subjective Shoulder Value, Activities of Daily Life that require External Rotation, and Disabilities of the Arm, Shoulder, and Hand), range of motion (ROM), complications, revisions, and notching. Meta-analyses were performed when possible. Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were followed.

RESULTS

Fifteen articles/16 studies were included (865 participants: 440 L-RSA and 425 S-RSA). Most studies found no differences between the L-RSA and S-RSA groups in qualitative and meta-analysis for American Shoulder and Elbow Surgeons, Constant, Simple Shoulder Test, Activities of Daily Life that require External Rotation, and Disabilities of the Arm, Shoulder, and Hand scores. Meta-analysis demonstrated significantly lower visual analog scale (1 point) and higher Subjective Shoulder Value (6 points) in L-RSA than in S-RSA. No significant differences were found in the qualitative analyses of most studies regarding ROM in forward elevation, abduction, and internal/external rotation, but meta-analysis reported a significantly higher external rotation in L-RSA groups and specifically in osseous lateralization. Complication rate was significantly lower in L-RSA (odds ratio = 0.38), but no significant differences were found for revision rates. Notching rate was significantly lower in the L-RSA group (odds ratio = 0.14), both for osseous and metallic lateralization.

DISCUSSION/CONCLUSION

This systematic review focused on studies comparing L-RSA and S-RSA and found significantly lower notching and complication rates in L-RSA groups. This review highlighted similar outcomes in clinical scores and a slight advantage for L-RSA in ROM, especially in external rotation. L-RSA was not associated with increased revision rates, while presenting lower complication and notching rates. Inclusion of studies with metallic and osseous lateralization has helped to provide further evidence on this subject, but heterogeneity and low evidence levels of the included studies may limit our conclusions.

Does preoperative diagnosis impact patient outcomes following reverse total shoulder arthroplasty? A systematic review

BACKGROUND

The indications for reverse total shoulder arthroplasty (rTSA) have expanded to include the treatment of a wide variety of shoulder pathologies, and there may be significant differences in patient outcomes based on preoperative diagnosis.

METHODS

A systematic review of the orthopedic literature contained in the PubMed, Cochrane, and Embase databases was performed on November 14, 2019. Studies investigating rTSA indicated for 7 distinct preoperative diagnoses (massive rotator cuff tear [MCT] without glenohumeral osteoarthritis [GHOA], MCT with GHOA or cuff tear arthropathy, primary GHOA, inflammatory arthritis with MCT, failed shoulder arthroplasty, proximal humeral fracture [PHF], and sequelae following PHF) were included. The main outcomes of interest included functional outcomes (abduction, external rotation, and forward flexion) and patient-reported outcome measures (American Shoulder and Elbow Surgeons shoulder score and Constant-Murley score). Because of significant variation in measurement and reporting, data on internal rotation were not extracted. In addition, radiographic outcomes and complication rates were extracted and recorded for each of the included studies.

RESULTS

In total, 47 studies, comprising 2280 patients, met the inclusion criteria. Significant improvements in functional outcomes and patient-reported outcome measures were found across the preoperative diagnostic groups. There were no significant differences between the diagnostic groups regarding improvement between preoperative and postoperative values for the outcomes of interest, with the exception that the inflammatory arthropathy group had significantly less improvement in the Constant-Murley score than the primary GHOA and revision arthroplasty groups. Although there were few differences in improvement between groups, there were significant differences regarding the level of postoperative functional performance, which was not as consistent in the context of trauma or revision operations (ie, complex PHF, fracture sequela, and revision arthroplasty groups).

CONCLUSION

Reverse total shoulder arthroplasty can provide reliable improvement in clinical outcomes regardless of preoperative diagnosis, with few differences across diagnostic groups regarding preoperative to postoperative improvement. The groups with primary GHOA and MCTs with or without GHOA demonstrated the most reliable postoperative functional outcomes of the examined diagnostic groups. Postoperative outcomes were not as consistent in the context of trauma or revision operations, and these groups may benefit from a variety of modern advancements in rTSA, although further research into these modalities for these groups is needed. Finally, rTSA remains an important treatment option in the context of rheumatoid arthritis, with similar outcomes and complication rates compared with the 6 other operative indications.

The glenoid-intramedullary humeral angle: a measurement of compensatory scapular abduction in advanced rotator cuff arthropathy and its potential effects on implant choice

Background

This study establishes measurements to evaluate pathologic compensation in rotator cuff tear arthropathy and resultant considerations for reverse shoulder arthroplasty.

Methods

Radiographs of patients with intact rotator cuffs were measured establishing interobserver and intraobserver reliability. Reverse shoulder arthroplasty cases performed by a single surgeon were then retrospectively reviewed. One year of follow-up radiographs were required for inclusion. Preoperative radiographs were analyzed for relative humeral head elevation ratio and humeral abduction relative to the glenoid face, termed the glenoid-intramedullary humeral angle. Statistical analyses assessed associations for radiographic measurements with presence and severity of scapular notching based on the Nerot-Sirveaux classification system.

Results

A total of 221 patients met inclusion criteria. At the 1-year follow-up, 61 (27.6%) shoulders had radiographic notching. There was a moderately strong (r = -0.56) negative correlation between glenoid-intramedullary humeral angle and humeral head elevation ratio. Patients with humeral head elevation ratio ≥ 20% were significantly (P = .024) and 9.2 times more likely to have notching of any grade. Patients with glenoid-intramedullary humeral angle ≤ 5 degrees were significant (P < .0001) and 6.7 times more likely to have notching of any grade and significantly (P = .00018) and 145 times more likely to have high-grade (3 and 4) notching.

Conclusions

Preoperative humeral head elevation and compensatory scapular rotation with relative adduction of the humerus have significant associations with high-grade notching. These radiographic findings have potential to help surgeons in preoperative decision-making regarding implant choice and patient education.

Impact of humeral and glenoid component variations on range of motion in reverse geometry total shoulder arthroplasty: a standardized computer model study

BACKGROUND

Multiple modifications of reverse total shoulder arthroplasty (RTSA) since the first Grammont design have developed to improve range of motion (ROM) and avoid notching. The effect of these changes in shoulder kinematics and the best compromise for ROM is still under debate. This computer simulation study evaluates the influence of humeral design, humeral neck-shaft angle (NSA), glenoid lateralization, and glenoid eccentricity on ROM of RTSA.

METHODS

We created a 3-dimensional computer model from computed tomography scans of 13 patients with primary osteoarthritis simulating implantation of a standardized reverse shoulder arthroplasty. We analyzed the effect of 4 different variables on impingement-free ROM: humeral design (inlay vs. semi-inlay vs. onlay), humeral NSA (135° vs. 145° vs. 155°), glenoid lateralization, and glenoid eccentricity on ROM.

RESULTS

The use of different humeral stem designs did not have a significant effect on total global ROM. Reducing NSA demonstrated a significant increase in adduction, and external and internal rotation in adduction, whereas a decrease in abduction and external rotation in abduction. Glenosphere lateralization was the most effective method for increasing total global ROM (P < .0001); however, extreme lateralization (+12 mm) did not show significant benefit compared with moderate lateralization (+4 mm). Glenosphere eccentricity increased only adduction and internal rotation in adduction.

CONCLUSION

Only glenoid lateralization has a significant effect on increasing total global ROM in RTSA. The use of the semi-inlay 145° model combined with 4 mm lateralization and 2 mm inferior eccentricity represents the middle ground and the most universal approach in RTSA.

Offset in Reverse Shoulder Arthroplasty: Where, When, and How Much

Since the advent of Paul Grammont medialized reverse shoulder prosthesis in the 1980s, shoulder surgeons have had a reliable option for treating glenohumeral joint disease in the rotator cuff-deficient shoulder. However, the prosthesis is not without complications, including scapular notching, instability, and limited rotational motion. Implants have been modified from the original design in an effort to reduce the risk of these complications. Increasing the offset, or lateralization, of the glenosphere may reduce the rate of scapular notching, reduce impingement, increase stability, and improve rotational motion. However, a more lateralized glenosphere could lead to baseplate loosening, decreased deltoid efficiency, and increased risk of acromial fracture. Increasing the offset on the humeral side, rather than the glenosphere side, may be able to reduce the rate of scapular notching and improve rotational motion without an increased risk of baseplate loosening. Humeral lateralization also improves tension of the rotator cuff and maintains good deltoid efficiency. However, humeral lateralization provides little stability benefit, and acromial fracture remains a risk. Ultimately, the surgeon must be familiar with the implants he or she is using and the options for both glenosphere and humeral lateralization to ensure that risks and benefits can be weighed for each patient.

Software simulations of changing offsets and thus soft tissue tension when revising anatomic to reverse total shoulder arthroplasty in convertible platform systems

BACKGROUND

Revision shoulder arthroplasty may involve the need to remove a well-fixed humeral stem. To avoid this, convertible platform systems have been introduced. The biomechanics of reverse total shoulder arthroplasty (rTSA) differs from anatomic shoulder arthroplasty (aTSA). The different humeral osteotomy and soft tissue tension may jeopardize the optimal results of the converted rTSA. The aim was to evaluate the radiographic parameters of soft tissue distraction when converting an aTSA to rTSA in a platform system and assess the capability of conversion without "over-stuffing" the shoulder in the "best-case scenario".

METHODS

Radiographic analysis of soft tissue distraction parameters: difference in acromio-humeral distance, difference in lateral humeral offset and difference in latero-inferior displacement were evaluated in aTSA and in the converted rTSA in six different implants. Image analysing software was used on 10 non-deformed osteoarthritic shoulder X-rays to simulate conversion.

RESULTS

The greatest increase in arm length was found for Tornier Ascend Flex (26.8 ± 3.6 mm) while the smallest increase was observed with Lima SMR (19.3 ± 4 mm). The humerus remained most lateralized with the Zimmer Anatomical/Inverse ( - 1.4 ± 2.9 mm) while Lima SMR ( - 15.8 ± 2.7 mm) was more medialized. The greatest increase in latero-inferior distance was found in the onlay systems. A group analysis of onlay rTSA showed an increase of 46% in arm length (p < 0.0001), 83% larger humeral offset (p < 0.0001) and 144% increase in latero-inferior distraction (p < 0.0001) when compared to inlay rTSA.

CONCLUSION

The conversion of aTSA to rTSA using a convertible platform system may lead to significant increase in radiographic parameters corresponding to soft tissue tension. This may alter the biomechanics, restrict the convertibility or jeopardize the optimal clinical outcome of rTSA even in the best-case scenario.

Lateralization in reverse shoulder arthroplasty: A review

Reverse shoulder arthroplasty, as originally designed by Grammont, has revolutionized the treatment of rotator cuff arthropathy as well as fractures about the proximal humerus. The original design consisted of glenoid and humeral components with a medialized center or rotation compared to the native shoulder. Long term outcome studies on this design demonstrated high rates of scapular notching as well as significant loss of external rotation. To combat these flaws, prosthesis design has evolved to include the concept of lateralization whereby the center of rotation is moved laterally compared to the Grammont prosthesis via either the glenoid or humeral components. Lateralization via the glenoid component has sought to reduce scapular notching, however, concerns over early loosening have been raised secondary to increasing stress at the glenosphere/glenoid interface. Lateralization via the humeral component has been theorized to improve the mechanics of the remaining rotator cuff and deltoid musculature while avoiding the problems inherent with glenoid lateralization. While limited clinical evidence is available currently to support one design over the other, multiple biomechanical studies have shown improvements in rates of scapular notching and post-operative external rotation for lateralized humeral and glenoid components. Future research should aim to delineate advantages of one design over the other or optimal combinations of the two designs.

Clinical results of bony increased-offset reverse shoulder arthroplasty (BIO-RSA) associated with an onlay 145° curved stem in patients with cuff tear arthropathy: a comparative study

BACKGROUND

The main limits of the Grammont design reverse shoulder arthroplasty (RSA) are loss of external rotation and scapular notching. They can be addressed with glenoid or humeral lateralization. The aim of the study was to compare outcomes of lateralized bony increased-offset RSA (BIO-RSA) vs. standard RSA in patients with an onlay 145° curved stem.

METHODS

A comparative cohort study of 29 standard RSAs and 30 BIO-RSAs was performed. At 2 years postoperatively, Constant score, American Shoulder and Elbow Surgeons score, visual analog scale score, range of motion, and radiographs were evaluated. After comparison between the groups, patients were analyzed considering patients younger and older than 65 years.

RESULTS

All parameters significantly improved after surgery in both groups. Postoperatively, the 2 groups did not show any clinical and radiographic differences (P > .05). In patients <66 years, BIO-RSA showed a significantly higher value of external rotation (49° ± 12° vs. 30° ± 19° [P = .025], elbow at side; 81° ± 17° vs. 56° ± 22° [P = .016], elbow at 90° of abduction) and a positive trend for all other parameters (P > .05). In patients >65 years, standard technique showed a positive trend for all the parameters (P > .05). No other significant differences were found.

CONCLUSIONS

At 2 years of follow-up, the use of standard RSA or BIO-RSA in an implant with an onlay 145° curved stem provided similar outcomes. The humeral lateralization alone is sufficient to decrease notching and to improve external rotation. BIO-RSA increases external rotation in patients between 50 and 65 years old. Glenoid bone graft in RSA has a high incorporation rate (completed in 90%).

Factors associated with internal rotation outcomes after reverse shoulder arthroplasty

BACKGROUND

Reverse shoulder arthroplasty (RSA) was introduced in 1985 by Grammont for patients with gleno-humeral osteoarthritis and severe rotator cuff damage. Internal rotation (IR) is limited in some patients after RSA. The objective of this study was to identify pre- and intra-operative factors associated with good IR outcomes 6 months after RSA.

HYPOTHESIS

The condition of the residual cuff (usually the sub-scapularis and teres minor) and inferior glenosphere overhang are the main factors associated with IR outcomes after RSA.

MATERIAL AND METHOD

A total of 36 patients who underwent RSA between 2 November 2015 and 10 January 2017 were enrolled prospectively. The inclusion criterion was massive rotator cuff tear with or without osteoarthritis and gleno-humeral osteoarthritis with asymmetrical glenoid wear. The pre-operative work-up included determination of the Constant score, Subjective Shoulder Value (SSV), and passive and active motion ranges; standard radiographs; and computed tomography. The same clinical and radiological parameters were recorded in all patients during a visit 6 months after surgery.

RESULTS

After surgery, all motion ranges were improved except IR with the elbow by the side (IR1, ability to place the hand on the back). IR1 to or above L3 was significantly associated with a lower body mass index (p=0.04), good passive IR before surgery (p=0.056), a smaller pre-operative glenoid inclination angle, and greater glenosphere overhang (p=0.03). Neither the condition of the sub-scapularis nor sub-scapularis repair were significantly associated with post-operative IR1. IR1 was significantly more limited in patients whose teres minor was normal.

CONCLUSION

Satisfactory active IR1 correlated with good passive IR1. IR1 was better in thin individuals who had non-concentric gleno-humeral osteoarthritis. Inferior glenosphere overhang of 6mm or more was associated with a greater range of IR.

LEVEL OF EVIDENCE

IV, prospective observational cohort study.

Imaging of Shoulder Arthroplasties

OBJECTIVE

In this article, we review the preoperative imaging features used for planning shoulder arthroplasty as well as review the various shoulder arthroplasty component types, discussing the expected normal imaging features and specific complications to look for with each.

CONCLUSION

Given the increasing use of shoulder arthroplasty, it is important to understand the imaging features of the various shoulder arthroplasty complications.

Factors associated with poor active anterior elevation after reverse total shoulder arthroplasty

BACKGROUND

Although reverse total shoulder arthroplasty (RTSA) has been shown to reduce pain and to improve function in most patients, some still suffer from functional limitations. This study aimed to investigate the incidence of poor motion recovery after RTSA and to identify factors that may cause poor outcomes.

METHODS

Seventy-six patients who underwent primary RTSA with a reverse-type Aequalis prosthesis (Tornier, Montbonnot, France) were allocated to a satisfactory or unsatisfactory group on the basis of their postoperative active anterior elevation. The average age of the patients was 69 ± 8 years (range, 42-82 years); average follow-up period was 34 ± 12 months (range, 24-93 months).

RESULTS

Fifty-eight patients had a satisfactory outcome (satisfactory group) and 18 had an unsatisfactory outcome (unsatisfactory group). Twenty-seven patients (46.6%) in the satisfactory group and 10 (55.6%) in the unsatisfactory group had preoperative pseudoparalysis (P = .504). Pre-existing medical comorbidities, such as thyroid disease, hypertension, diabetes, and smoking, showed no significant differences. Anterior deltoid muscle belly volume also did not significantly differ between the satisfactory and unsatisfactory groups. However, mean postoperative lateral humeral offset (LHO) was -2 ± 6 mm in the satisfactory group and 3 ± 5 mm in the unsatisfactory group (P = .001).

CONCLUSION

Satisfactory improvement of active anterior elevation was achieved in three-quarters of patients who underwent RTSA using a prosthesis designed to be medialized. Of the factors we investigated, only postoperative LHO was found to be a significant risk factor for poor postoperative active anterior elevation. Therefore, surgeons should attempt to avoid increasing postoperative LHO when performing RTSA using an implant designed to be medialized.

Restoration of External Rotation Following Reverse Shoulder Arthroplasty without Latissimus Dorsi Transfer

Background

Latissimus dorsi transfers have been considered necessary to restore active external rotation following reverse shoulder arthroplasty (RSA). The purpose of this study was to assess the effectiveness of an RSA system that lateralizes the center of rotation in restoring active external rotation without a latissimus dorsi transfer in patients with a preoperative external rotation deficit (external rotation of <0°).

Methods

We retrospectively reviewed the records of patients who had undergone RSA with a lateralized center of rotation without a latissimus dorsi transfer. All patients had had a preoperative external rotation deficit (active external rotation of <0°), and all were followed for a minimum of 2 years. Patients were stratified into 2 groups on the basis of the preoperative diagnosis: (1) those with a combined loss of active elevation and external rotation as a result of rotator cuff tear arthropathy (CLEER group) and (2) those with a combined loss of active elevation and external rotation as a result of other posttraumatic etiologies (non-CLEER group). The mean improvement of external rotation was analyzed. Subgroup analysis was performed on the basis of the Goutallier classification, glenosphere lateralization, and total prosthetic lateralization.

Results

Thirty-three patients (24 in the CLEER group and 9 in the non-CLEER group) met the inclusion criteria. The average follow-up was 43.4 months (range, 24 to 77 months). External rotation improved significantly in both the CLEER group (from -21° preoperatively to 28° postoperatively; p < 0.001) and the non-CLEER group (from -19° preoperatively to 26° postoperatively; p = 0.001). Goutallier classification, glenosphere lateralization, and total prosthetic lateralization were not correlated with the degree of improvement of external rotation in either group (p > 0.05 for all).

Conclusions

RSA with a lateralized center of rotation can effectively restore external rotation without the use of a latissimus dorsi transfer in patients with a preoperative external rotation deficit as a result of rotator cuff arthropathy or other posttraumatic etiologies.

Level of Evidence

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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