The lateralization and distalization shoulder angles are important determinants of clinical outcomes in reverse shoulder arthroplasty

Locked Stem Reverse Total Shoulder Arthroplasty for Complex Proximal Humerus Fracture in the Elderly: Clinical and Radiological Short-Term Results

Purpose

To evaluate both the short-term clinical and radiological results of reverse shoulder arthroplasty (RSA) with uncemented locked stem in the management of a proximal humerus fracture (PHFs) in the elderly.

Methods

Retrospective study including 40 consecutive 3-4 part proximal humerus fractures treated with reverse shoulder arthroplasty with a minimum of 24 months follow-up. In all the cases, the greater tuberosity (GT) was reattached with a standardized suture technique and a local horseshoe bone graft. All the patients were assessed at the 24-month follow-up with Constant-Murley Score (CMS) and Visual Analog Score (VAS). Radiographic healing of the greater tuberosity was noted in addition to stem locking screws radiographic changes. Complications and revision rates were reported.

Results

Mean final CMS for this cohort was 80 points. The greater tuberosity healed in the anatomic position in 90% of the cases (N = 36), obtaining an average CMS of 80 in these patients. Healing of the greater tuberosity did not occur in 10% of the cases (N = 4), obtaining an average CMS of 60. All patients scored above 100° in forward elevation with a mean of 140°. Mean active external rotation was 30°. Low-grade scapular notching was reported in <1% of the cases. Major complications were reported in one patient with an acromial fracture. No complications or loosening of stem locking screws were noted. There were no reoperations.

Conclusion

In the elderly population, reverse shoulder arthroplasty utilizing a fracture-specific locking stem, low-profile metaphysis, suture-friendly groove, meticulous suture technique, and local bone grafting allows adequate fixation, variable prosthesis height adjustment, and enhances greater tuberosity healing. This approach yields positive short-term clinical outcomes without complications related to the stem's locking screws.

Level of Evidence

Level IV Retrospective Case Series.

Is preoperative 3D planning reliable for predicting postoperative clinical differences in range of motion between two stem designs in reverse shoulder arthroplasty

BACKGROUND

We aim to predict a clinical difference in the postoperative range of motion (RoM) between 2 reverse shoulder arthroplasty (RSA) stem designs (Inlay-155° and Onlay-145°) using preoperative planning software. We hypothesized that preoperative 3D planning could anticipate the differences in postoperative clinical RoM between 2 humeral stem designs and by keeping the same glenoid implant.

METHODS

Thirty-seven patients (14 men and 23 women, 76 ± 7 years) underwent a BIO-RSA (bony increased offset-RSA) with the use of preoperative planning and an intraoperative 3-dimensional-printed patient-specific guide for glenoid component implantation between January 2014 and September 2019 with a minimum follow-up of 2 years. Two types of humeral implants were used: Inlay with a 155° inclination (Inlay-155°) and Onlay with a 145°inclination (Onlay-145°). Glenoid implants remained unchanged. The postoperative RSA angle (inclination of the area in which the glenoid component of the RSA is implanted) and the lateralization shoulder angle were measured to confirm the good positioning of the glenoid implant and the global lateralization on postoperative X-rays. A correlation between simulated and clinical RoM was studied. Simulated and last follow-up active forward flexion (AFE), abduction, and external rotation (ER) were compared between the 2 types of implants.

RESULTS

No significant difference in RSA and lateralization shoulder angle was found between planned and postoperative radiological implants' position. Clinical RoM at the last follow-up was always significantly different from simulated preoperative RoM. A low-to-moderate but significant correlation existed for AFE, abduction, and ER (r = 0.45, r = 0.47, and r = 0.57, respectively; P < .01). AFE and abduction were systematically underestimated (126° ± 16° and 95° ± 13° simulated vs. 150° ± 24° and 114° ± 13° postoperatively; P < .001), whereas ER was systematically overestimated (50° ± 19° simulated vs. 36° ± 19° postoperatively; P < .001). Simulated abduction and ER highlighted a significant difference between Inlay-155° and Onlay-145° (12° ± 2°, P = .01, and 23° ± 3°, P < .001), and this was also retrieved clinically at the last follow-up (23° ± 2°, P = .02, and 22° ± 2°, P < .001).

CONCLUSIONS

This study is the first to evaluate the clinical relevance of predicted RoM for RSA preoperative planning. Motion that involves the scapulothoracic joint (AFE and abduction) is underestimated, while ER is overestimated. However, preoperative planning provides clinically relevant RoM prediction with a significant correlation between both and brings reliable data when comparing 2 different types of humeral implants (Inlay-155° and Onlay-145°) for abduction and ER. Thus, RoM simulation is a valuable tool to optimize implant selection and choose RSA implants to reach the optimal RoM.

The lateralization and distalization index is more reliable than angular radiographic measurements in reverse shoulder arthroplasty

BACKGROUND

The lateralization shoulder angle (LSA) and distalization shoulder angle (DSA) are used to reproducibly measure lateralization and distalization after reverse shoulder arthroplasty (RSA). However, LSA and DSA may not offer a precise measurement of humeral lateralization and distalization and this relationship has not been explored. The aim of this study was to evaluate the validity of these measurements and to propose new measurement methods to estimate implant lateralization and distalization.

METHODS

3D models were constructed from computed tomography (CT) scans of 30 patients using a software platform. For each patient 24 different RSA modifications were created, resulting in 720 different RSA configurations. For each configuration LSA and DSA angles as well as lateralization and distalization distances were measured. Moreover, for each configuration two new measurements were done: the lateralization index (LI) and distalization index (DI). Correlations of the lateralization and distalization parameters were evaluated between measurements.

RESULTS

Weak correlations were founded between LSA and lateralization (r = 0.36, p < 0.01), whereas moderate correlations were observed between LI and lateralization (r = 0.72, p < 0.01). No significant correlations were found between DSA and distalization (r = 0.17, p = 0.113). In contrast, moderate correlations were identified between DI and distalization (r = 0.69, p < 0.01).

CONCLUSION

LI and DI are more reliable methods to estimate implant lateralization and distalization compared to angular radiographic measurements. However, the prognostic significance in predicting clinical outcomes after RSA remains unknown.

Metallic Lateralized-Offset Glenoid Reverse Shoulder Arthroplasty

Background

Metallic lateralized-offset glenoid reverse shoulder arthroplasty (RSA) for cuff tear arthropathy combines the use of a metallic augmented baseplate with a metaphyseally oriented short stem design that can be applied at a 135° or 145° neck-shaft angle, leading to additional lateralization on the humeral side. Lateralization of the center of rotation decreases the risk of inferior scapular notching and improves external rotation, deltoid wrapping, residual rotator cuff tensioning, and prosthetic stability1-4. Metallic increased-offset RSA (MIO-RSA) achieves lateralization and corrects inclination and retroversion while avoiding graft resorption and other complications of bony increased-offset RSA (BIO-RSA)5-8. Reducing the neck-shaft angle from the classical Grammont design, in combination with glenoid lateralization, improves range of motion9,10 by reducing inferior impingement during adduction at the expense of earlier superior impingement during abduction2,11. Lädermann et al.12 investigated how different combinations of humeral stem and glenosphere designs influence range of motion and muscle elongation. They assessed 30 combinations of humeral components, as compared with the native shoulder, and found that the combination that allows for restoration of >50% of the native range of motion in all directions was a 145° onlay stem with a concentric or lateralized tray in conjunction with a lateralized or inferior eccentric glenosphere. In addition, the use of a flush-lay or a slight-onlay stem design (like the one utilized in the presently described technique) may decrease the risk of secondary scapular spine fracture13,14. The goal of this prosthetic design is to achieve an excellent combination of motion and stability while reducing complications.

Description

This procedure is performed via a deltopectoral approach with the patient in the beach-chair position under general anesthesia combined with a regional interscalene nerve block. Subscapularis tenotomy and capsular release are performed, the humeral head is dislocated, and any osteophytes are removed. An intramedullary cutting guide is placed for correct humeral resection. The osteotomy of the humeral head is performed in the anatomical neck with an inclination of 135° and a retroversion of 20° to 40°, depending on the anatomical retroversion. The glenoid is prepared as usual. The lateralized, augmented baseplate is assembled with the central screw and the baseplate-wedge-screw complex is placed by inserting the screw into the central screw hole. Four peripheral screws are utilized for definitive fixation. An eccentric glenosphere with inferior overhang is implanted. The humerus is dislocated, and the metaphysis is prepared. Long compactors are utilized for proper stem alignment, and an asymmetric trial insert is positioned before the humerus is reduced. Stability and range of motion are assessed. The definitive short stem is inserted and the asymmetric polyethylene is impacted, resulting in a neck-shaft angle of 145°. Following reduction, subscapularis repair and wound closure are performed.

Alternatives

BIO-RSA is the main alternative to MIO-RSA. Boileau et al.15 demonstrated satisfactory early and long-term outcomes of BIO-RSA for shoulder osteoarthritis. A larger lateral offset may also be achieved with a thicker glenosphere2,16. Mark A. Frankle developed an implant that addressed the drawbacks of the Grammont design: a lateralized glenosphere combined with a 135° humeral neck-shaft angle. The 135° neck-shaft angle provides lateral humeral offset, preserving the normal length-tension relationship of the residual rotator cuff musculature, which optimizes its strength and function. The lateralized glenosphere displaces the humeral shaft laterally, minimizing the potential for impingement during adduction2,9,17,18. The advantage of BIO-RSA and MIO-RSA over lateralized glenospheres is that the former options provide correction of angular deformities without excessive reaming, which can lead to impingement19.

Rationale

BIO-RSA has been proven to achieve excellent functional outcomes15,20,21; however, the bone graft can undergo resorption, which may result in early baseplate loosening. Bipolar metallic lateralized RSA is an effective strategy for achieving lateralization and correction of multiplanar defects while avoiding the potential complications of BIO-RSA6,7,22-24. MIO-RSA also overcomes another limitation of BIO-RSA, namely that BIO-RSA is not applicable when the humeral head is not available for use (e.g., humeral head osteonecrosis, revision surgery, fracture sequelae).

Expected Outcomes

A recent study evaluated the clinical and radiographic outcomes of metallic humeral and glenoid lateralized implants. A total of 42 patients underwent primary RSA. Patients were documented prospectively and underwent follow-up visits at 1 and 2 years postoperatively. That study demonstrated that bipolar metallic lateralized RSA achieves excellent clinical results in terms of shoulder function, pain relief, muscle strength, and patient-reported subjective assessment, without instability or radiographic signs of scapular notching23. Kirsch et al.25 reported the results of primary RSA with an augmented baseplate in 44 patients with a minimum of 1 year of clinical and radiographic follow-up. The use of an augmented baseplate resulted in excellent short-term clinical outcomes and substantial deformity correction in patients with advanced glenoid deformity. No short-term complications and no failure or loosening of the augmented baseplate were observed. Merolla et al.7 compared the results of 44 patients who underwent BIO-RSA and 39 patients who underwent MIO-RSA, with a minimum follow-up of 2 years. Both techniques provided good clinical outcomes; however, BIO-RSA yielded union between the cancellous bone graft and the surface of the native glenoid in <70% of patients. On the other hand, complete baseplate seating was observed in 90% of MIO-RSA patients.

Important Tips

When performing subscapularis tenotomy, leave an adequate stump to allow end-to-end repair.Tenotomize the superior part of the subscapularis tendon in an L-shape, sparing the portion below the circumflex vessels.As glenoid exposure is critical, perform a 270° capsulotomy.Continuously check the orientation of the baseplate relative to the prepared hole and reamed surface to ensure accurate implantation of the full wedge baseplate to achieve a proper fit.Aim for 70% to 80% seating of the baseplate onto the prepared glenoid surface. Avoid overtightening or excessive advancement of the baseplate into the subchondral bone. Gaps between the baseplate and glenoid surface should also be avoided.In order to avoid varus or valgus malpositioning of the final implant, obtain proper diaphyseal alignment by following "the three big Ls": large, lateral, and long. Use a large metaphyseal component to fill the metaphysis. Place the guide pin for the reaming of the metaphysis slightly laterally into the resected surface of the humerus. Use long compactors for diaphyseal alignment to avoid varus or valgus malpositioning of the final implant.Use an intramedullary cutting guide for correct humeral resection.Utilize the correct liner in order to obtain proper tensioning and avoid instability.

Acronyms and Abbreviations

K wire = Kirschner wireROM = range of motion.

Functional and radiographic outcomes of reverse shoulder arthroplasty with a minimum follow-up of 10 years

BACKGROUND

The use of reverse shoulder arthroplasty (RSA) is becoming increasingly prevalent. However, few studies have been published reporting the long-term outcomes of RSA. This study aims to report the clinical, radiographic, and patient-reported outcomes of the Delta Xtend reverse shoulder prosthesis, performed by a single surgeon and with a minimum follow-up of 10 years.

METHODS

All RSA procedures performed between 2005 and 2012 were identified. Patients were contacted and invited for a follow-up visit including clinical assessment, radiographs, and patient-reported outcome measures. Patients with a follow-up of less than 10 years were excluded. The revision-free implant survival was calculated at 10 years. Between 2005 and 2012, 119 procedures in 116 patients meeting inclusion criteria were identified. Of these patients, 35 were deceased before reaching the 10-year follow-up and 23 could not be reached. In total, 63 RSAs could be included in 61 patients (response rate: 75%). The median follow-up was 11.7 years (interquartile range [IQR]: 10.5-13.2).

RESULTS

Of the 61 patients, 7 patients underwent a revision after a median of 3 years (IQR: 0.2-9.8) during the total follow-up period. The 10-year implant survival was 94% (95% confidence interval: 84-98). At final follow-up, the median anterior elevation was 135° (IQR: 130°-160°), the median abduction was 120° (IQR: 100°-135°), and the median level reached with internal rotation was L5 (IQR: sacrum-L5). The median Auto-Constant score was 68 (IQR: 53-78), the median Subjective Shoulder Value was 80 (IQR: 70-93), and the median pain score was 0.2/10 (IQR: 0-2). In total, radiographs could be obtained in 25 patients (40%). Scapular notching occurred in 10 patients (40%), which was classified as Sirveaux-Nerot grade IV in 3 patients (12%). Ossification occurred in 10 patients (40%), and stress shielding in 2 patients (8%). Radiolucencies were observed around the humeral component in 24 patients (96%) and around the glenoid component in 13 patients (52%).

CONCLUSION

The long-term results of RSA with a Delta Xtend prosthesis are favorable, with long-term improvement in range of motion and patient-reported outcome measures, and a satisfactory implant survival rate. Interestingly, the radiographical analysis showed high prevalence of signs associated with loosening, which did not seem to translate to high complication rates or inferior results.

The effect of lateralization and distalization after Grammont-style reverse total shoulder arthroplasty

BACKGROUND

The purpose of this study was to evaluate the relationship between multiple radiographic measures of lateralization and distalization and clinical outcome scores after a reverse total shoulder arthroplasty (RTSA).

METHODS

We retrospectively evaluated all RTSAs performed by the senior author between January 1, 2007, and November 1, 2017. We then evaluated the visual analog scale for pain (VAS pain), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons (ASES) scores and complication and reoperation rates at a minimum of 2-year follow-up. We measured preoperative and postoperative (2-week) radiographs for the lateralization shoulder angle (LSA), the distalization shoulder angle (DSA), lateral humeral offset, and the distance from the glenoid to the lateral aspect of the greater tuberosity. A multivariable analysis was performed to evaluate the effect of the postoperative radiographic measurements on final patient-reported outcomes (ASES scores, SST, and VAS pain).

RESULTS

The cohort included 216 shoulders from unique patients who had patient-reported outcome scores available at a minimum of 2-year follow-up (average, 4.0 ± 1.9 years) for a total follow-up rate of 70%. In the multivariable models, more lateralization (LSA) was associated with worse final ASES scores -0.52 (95% confidence interval [CI]: -0.88, -0.17; P = .004), and more distalization (DSA) was associated with better final ASES scores 0.40 (95% CI: 0.11, 0.69; P = .007). More lateralization (LSA) was associated with worse final SST scores -0.06 (95% CI: -0.11, -0.003; P = .039). Finally, greater distalization (DSA) was associated with lower final VAS pain scores, ratio = 0.98 (95% CI: 0.96, 1.00; P = .021).

CONCLUSIONS

Greater distalization and less lateralization are associated with better function and less pain after a Grammont-style RTSA. When using a Grammont-style implant, remaining consistent with Grammont's principles of implant placement will afford better final clinical outcomes.

Can we separately measure glenoid vs. humeral lateralization and distalization in reverse shoulder arthroplasty?

BACKGROUND

Lateralization and distalization in reverse shoulder arthroplasty (RSA) can be measured on anteroposterior (AP) radiographs using 2 previously described angles: lateralization shoulder angle (LSA) and distalization shoulder angle (DSA). However, these 2 angles measure global lateralization and distalization but do not allow to differentiate how much lateralization or distalization are attributable to the glenoid and the humerus. We hypothesized that new angles could allow us to separately measure glenoid vs. humeral lateralization and distalization. A more precise understanding of independent glenoid and humeral contributions to lateralization and distalization may be beneficial in subsequent clinical research.

METHOD

Retrospective analysis of postoperative AP radiographs of 100 patients who underwent primary RSA for cuff-tear arthropathy, massive cuff tear, or glenohumeral osteoarthritis were analyzed. The new angles that we proposed use well-known bony landmarks (the acromion, glenoid, and humerus) and the most lateral point of the glenosphere, which we termed the "glenoid pivot point" (GPP). For lateralization, we used the GPP to split LSA into 2 new angles: glenoid lateralization angle (GLA) and humeral lateralization angle (HLA). For distalization, we introduced the modified distalization shoulder angle (mDSA) that can also be split into 2 new angles: glenoid distalization angle (GDA) and humeral distalization angle (HDA). Three orthopedic surgeons measured the new angles, using the online tool Tyche. Mean values with overall and individual standard deviations as well as intraclass correlation coefficients (ICCs) were calculated.

RESULTS

Because the angles form a triangle, the following equations can be made: LSA = GLA + HLA, and mDSA = GDA + HDA. All angles showed excellent inter- and intraobserver reliability (ICC = 0.92-0.97) with low means of individual standard deviations that indicate a precision of 2° for each angle.

CONCLUSION

Use of the most lateral part of the glenosphere (termed glenoid pivot point) allows us to separately measure glenoid vs. humeral lateralization and distalization. The 4 new angles (HLA, GLA, GDA, HDA) described in the present study can be used on true AP radiographs, routinely obtained after shoulder replacement, and the measured angles may be used with all types of reverse prostheses available.

The subcoracoid distance is correlated with pain and internal rotation after reverse shoulder arthroplasty

Background

A proposed etiology of anterior shoulder pain and limited internal rotation after reverse shoulder arthroplasty (RSA) is impingement of the humeral component on the coracoid or conjoint tendon. The primary goal of this study was to investigate radiographic surrogates for potential coracoid or conjoint tendon impingement and their relationship to postoperative pain and internal rotation after RSA.

Methods

A retrospective review of a clinical registry was performed to identify patients with (1) primary RSA, (2) minimum 2-year clinical follow-up, and (3) satisfactory postoperative axillary lateral radiographs. The primary radiographic measurement of interest was the subcoracoid distance (SCD), defined as the distance between the posterior aspect of the coracoid and the anterior glenosphere. Additional measurements were as follows: anterior glenosphere overhang, posterior glenosphere overhang, native glenoid width, lateralization of glenosphere relative to the coracoid tip, lateralization shoulder angle, and distalization shoulder angle. The primary clinical outcome of interest was the 2-year postoperative Visual Analog Scale score. Secondary outcomes were (1) internal rotation (IR) defined by spinal level (IRspine), (2) IR at 90 degrees of abduction, (3) American Shoulder and Elbow Surgeons score, (4) forward flexion, and (5) external rotation at 0 degrees of abduction. Linear regression analyses were used to evaluate the relationship of the various radiographic measures on the clinical outcomes of interest.

Results

Two hundred seventeen patients were included. There was a statistically significant relationship between the SCD and Visual Analog Scale scores: B = -0.497, P = .047. There was a statistically significant relationship between the SCD and IRspine: B = -1.667, P < .001. Metallic lateralization was also positively associated with improving IRspine; increasing body mass index was negatively associated. There was a statistically significant relationship between the SCD and IR at 90 degrees of abduction: B = 5.844, P = .034.

Conclusion

For RSA with a 135° neck shaft angle and lateralized glenoid, the postoperative SCD has a significant association with pain and IR. Decreasing SCD was associated with increased pain and decreased IR, indicating that coracoid or conjoint tendon impingement may be an important and potentially under-recognized etiology of pain and decreased IR following RSA. Further investigations aimed toward identifying a critical SCD to improve pain and IR may allow surgeons to preoperatively plan component position to improve clinical outcomes after RSA.

Rates of subacromial notching are low following reverse shoulder arthroplasty with a 135° inlay humeral component and a lateralized glenoid

Background

Lateralization in reverse shoulder arthroplasty (RSA) decreases bony impingement and improves rotational range of motion, but has been theorized to increase the risk of subacromial notching (SaN). The purpose of this study was to evaluate the presence of SaN following RSA and its relationship with lateralization with a 135° inlay humeral component. The secondary purpose was to assess the association of SaN with functional outcomes.

Methods

A retrospective review was performed from a multicenter prospectively collected database on patients who underwent primary RSA from 2015 to 2021. All RSAs were performed with a 135° inlay humeral component. SaN was defined as bony erosion with sclerotic margins on the undersurface of the acromion on final follow-up radiographs not present preoperatively. Postoperative implant positioning (inclination, distalization, and lateralization) were evaluated on minimum 1-year postoperative radiographs. Regression analyses were performed on implant and clinical variables to assess for risk factors. A separate analysis was performed to determine the association of SaN with clinical outcomes.

Results

SaN was identified in 13 out of 442 shoulders (2.9%). Age, sex, body mass index, smoking status, diabetes mellitus, arm dominance had no relationship with SaN. Neither glenoid sided lateralization nor humeral offset were associated with SaN risk. Other implant characteristics such as distalization, glenosphere size, and postoperative inclination did not influence SaN risk. The presence of SaN did not affect patient-reported outcomes (American Shoulder and Elbow Surgeons: P = .357, Visual Analog Scale: P = .210) or range of motion.

Conclusion

The rate of SaN is low and not associated with glenoid or humeral prosthetic lateralization when using a 135° inlay humeral component. When SaN occurs, it is not associated with functional outcomes or range of motion at short-term follow-up.

Lateralising reverse shoulder arthroplasty using bony increased offset (BIO-RSA) or increasing glenoid component diameter: comparison of clinical, radiographic and patient reported outcomes in a matched cohort

BACKGROUND

This study aims to compare the range of motion (ROM) of reverse shoulder arthroplasty lateralised by bony increased offset (BIO-RSA) using a standard 38-mm (mm) component to regular reverse shoulder arthroplasty (RSA) lateralised by using a 42-mm glenoid component. The secondary aims are to compare patient-reported and radiographic outcomes between the two groups.

MATERIALS AND METHODS

All patients with a BIO-RSA and size 38 glenosphere were retrospectively identified and matched to patients with a regular RSA and size 42 glenosphere. Matched patients were invited for a follow-up visit. ROM was assessed as well as radiographic outcomes (lateralisation, distalisation, inferior overhang, scapular notching, heterotopic bone formation, radiolucency, stress shielding, bone graft healing and viability and complications) and patient-reported outcomes (subjective shoulder value, Constant score, American Shoulder and Elbow Surgeons, activities of daily living which require internal rotation, activities of daily living which require external rotation and a visual analogue scale for pain). Outcomes were compared between the two groups.

RESULTS

In total, 38 BIO-RSAs with a size 38 glenosphere were matched to 38 regular RSAs with a size 42 glenosphere. Of the 76 matched patients, 74 could be contacted and 70 (95%) were included. At the final follow-up, there were no differences between the two groups in ROM, patient-reported outcomes or radiographic outcomes (p > 0.485).

CONCLUSIONS

Using a larger glenosphere is a feasible alternative to BIO-RSA for lateralising RSA, providing comparable ROM, patient-reported and radiographic results, while potentially decreasing costs, operative time and complication rates.

LEVEL OF EVIDENCE III

Factors affecting stress shielding and osteolysis after reverse shoulder arthroplasty: A multicenter study in a Japanese population

BACKGROUND

Stress shielding and osteolysis around the humeral stem after reverse shoulder arthroplasty causes loosening and periprosthetic fractures and reduces bone stock during revision surgery. In Japanese patients, who have relatively small bodies, different characteristics may exist regarding the occurrence of these changes compared with the characteristics of Westerners, who have relatively larger frames. The purpose of this multicenter study was to investigate the incidence and clarify the predictors of stress shielding and osteolysis in Japanese individuals who underwent reverse shoulder arthroplasty.

METHODS

The occurrence of stress shielding and osteolysis was investigated in 135 shoulders that had undergone reverse shoulder arthroplasty at least 2 years prior in five Japanese hospitals. During post-surgical follow-up, which was conducted every 3 months, the locations of the stress shielding occurrences, such as cortical thinning and osteopenia (which primarily occurred in zones 1, 2, and 7, where 1 is the greater tuberosity and 7 is the calcar part), spot weld, and condensation lines, were recorded. Cases without any abnormal findings on radiographs obtained up to ≥2 years after surgery were regarded as having no abnormalities. Finally, the predictors of cortical thinning and proximal humeral osteolysis were assessed using univariate and multivariate regression analyses.

RESULTS

Cortical thinning and osteopenia occurred in 68 shoulders, a condensation line occurred in 37 shoulders, and spot weld occurred in 23 shoulders. In particular, greater tuberosity and calcar osteolysis occurred in 40 and 47 shoulders, respectively. Long stem, cementless stem, and a larger proximal filling ratio were independent predictors of cortical thinning and osteopenia, whereas a cementless stem, larger metaphysis diameter, and a larger proximal filling ratio were associated with proximal humeral osteolysis.

CONCLUSIONS

The predictors of stress shielding and osteolysis included the use of long stems, cementless stems, larger proximal filling ratios, and larger metaphysis diameters.

LEVEL OF EVIDENCE

retrospective comparative study (Level III).

Managing rotator cuff tear arthropathy: a role for cuff tear arthropathy hemiarthroplasty as well as reverse total shoulder arthroplasty

BACKGROUND

Disabling cuff tear arthropathy (CTA) is commonly managed with reverse shoulder arthroplasty (RSA). However, for patients with CTA having preserved active elevation, cuff tear arthropathy hemiarthroplasty (CTAH) may offer a cost-effective alternative that avoids the complications unique to RSA. We sought to determine the characteristics and outcomes of a series of patients with CTA managed with these procedures.

MATERIALS AND METHODS

We retrospectively reviewed 103 patients with CTA treated with shoulder arthroplasty, the type of which was determined by the patient's ability to actively elevate the arm. Outcome measures included the change in the Simple Shoulder Test (SST), the percent maximum improvement in SST (%MPI), and the percentage of patients exceeding the minimal clinically important difference for the change in SST and %MPI. Postoperative x-rays were evaluated to assess the positions of the center of rotation and the greater tuberosity for each implant.

RESULTS

Forty-four percent of the 103 patients were managed with CTAH while 56% were managed with RSA. Both arthroplasties resulted in clinically significant improvement. Patients having RSA improved from a mean preoperative SST score of 1.7 (interquartile range [IQR], 0.0-3.0) to a postoperative score of 6.3 (IQR, 2.3-10.0) (P < .01). Patients having CTAH improved from a preoperative SST score of 3.1 (IQR, 1.0-4.0) to a postoperative score of 7.6 (IQR, 5.0-10.) (P < .001). These improvements exceeded the minimal clinically important difference. Instability accounted for most of the RSA complications; however, it did not account for any CTAH complications. The postoperative position of the center of rotation and greater tuberosity on anteroposterior radiographs did not correlate with the clinical outcomes for either procedure.

CONCLUSION

For 103 patients with CTA, clinically significant improvement was achieved with appropriately indicated CTAH and RSA. In view of the lower cost of the CTAH implant, it may provide a cost-effective alternative to RSA for patients with retained active elevation.

Influence of lateralized versus medialized reverse shoulder arthroplasty design on external and internal rotation: a systematic review and meta-analysis

BACKGROUND

Restoration of external (ER) and internal rotation (IR) after Grammont-style reverse shoulder arthroplasty (RSA) is often unreliable. The purpose of this systematic review was to evaluate the influence of RSA medio-lateral offset and subscapularis repair on axial rotation after RSA.

METHODS

We conducted a systematic review of studies evaluating axial rotation (ER, IR, or both) after RSA with a defined implant design. Medio-lateral implant classification was adopted from Werthel et al. Meta-analysis was conducted using a random-effects model.

RESULTS

Thirty-two studies reporting 2,233 RSAs were included (mean patient age, 72.5 years; follow-up, 43 months; 64% female). The subscapularis was repaired in 91% (n=2,032) of shoulders and did not differ based on global implant lateralization (91% for both, P=0.602). On meta-analysis, globally lateralized implants achieved greater postoperative ER (40° [36°-44°] vs. 27° [22°-32°], P<0.001) and postoperative improvement in ER (20° [15°-26°] vs. 10° [5°-15°], P<0.001). Lateralized implants with subscapularis repair or medialized implants without subscapularis repair had significantly greater postoperative ER and postoperative improvement in ER compared to globally medialized implants with subscapularis repair (P<0.001 for both). Mean postoperative IR was reported in 56% (n=18) of studies and achieved the minimum necessary IR in 51% of lateralized (n=325, 5 cohorts) versus 36% (n=177, 5 cohorts) of medialized implants.

CONCLUSIONS

Lateralized RSA produces superior axial rotation compared to medialized RSA. Lateralized RSA with subscapularis repair and medialized RSA without subscapularis repair provide greater axial rotation compared to medialized RSA with subscapularis repair. Level of evidence: 2A.

Reverse shoulder arthroplasty with a 155° neck-shaft angle inlay implant design without reattachment of the subscapularis tendon results in satisfactory functional internal rotation and no instability: a cohort study

BACKGROUND

The aim of this study was to use the Activities of Daily Living which require Internal Rotation (ADLIR) questionnaire to assess the functional internal rotation in patients who had undergone reverse shoulder arthroplasty (RSA) without reattachment of the subscapularis (SSc) tendon at a minimum follow-up of 2 years. The secondary aim was to report the objective range of motion (ROM) and the rate of postoperative instability.

MATERIALS AND METHODS

All consecutive primary RSA procedures without reattachment of the SSc tendon that were performed using a Delta Xtend prosthesis (an inlay system with a 155° neck-shaft angle) between January 2015 and December 2020 were identified to ensure a minimum follow-up of 2 years. Patients were contacted and requested to fill in several questionnaires, including the ADLIR and Auto-Constant scores.

RESULTS

In total, 210 patients met the inclusion criteria; among those patients, 187 could be contacted and 151 completed questionnaires (response rate: 81%). The SSc tendon was fully detached without repair in all cases, and a superolateral approach was used in 130 (86%) cases. The median follow-up was 4.5 years (range: 2.0-7.6). At final follow-up, the mean ADLIR score was 88/100 (interquartile range (IQR): 81-96). The median level reached in internal rotation was the 3rd lumbar vertebra (IQR: lumbosacral region-12th thoracic vertebra). Of the 210 eligible patients, one required a revision for a dislocation within the first month after primary surgery. With regards to regression analysis with ADLIR score as the outcome, none of the factors were associated with the ADLIR score, although age and smoking approached significance (0.0677 and 0.0594, respectively). None of the explanatory variables were associated with ROM in internal rotation (p > 0.05).

CONCLUSIONS

This study demonstrates that satisfactory ADLIR scores and internal rotation ROM were obtained at mid-term follow-up after RSA leaving the SSc detached. Leaving the SSc detached also did not lead to high instability rates; only one out of 210 prostheses was revised for dislocation within the first month after primary surgery.

LEVEL OF EVIDENCE III

Yoke procedure as a salvage treatment option for failed reverse total shoulder arthroplasty with irreconstructible glenoid

BACKGROUND

Glenoid bone loss is a known challenge in primary and revision reverse total shoulder arthroplasty. In severe deficiency, even placing the baseplate in alternative centerline or using an augmented baseplate may be insufficient. This study reports on the use of a soft tissue resurfacing technique using Achilles tendon allograft, coined Yoke procedure, for salvage treatment of glenoid deficient shoulder requiring reconstruction.

MATERIALS AND METHODS

All patients who underwent the Yoke procedure between 2014 and 2020 by a single surgeon at a single academic center were identified and had their charts retrospectively reviewed. Demographics and surgical information were recorded. Preoperative X-rays and 3D-computed tomography scans were reviewed to classify patient glenoid types, evaluate glenoid medialization, and measure shoulder angles. Preoperative and postoperative range of motions and patient-reported outcome scores were evaluated, including anterior elevation, external rotation, internal rotation, visual analog scale, subjective shoulder value score, Simple Shoulder Test, and American Shoulder and Elbow Surgeons (ASES) scores. Postoperative radiographs and follow-up notes were reviewed to evaluate postoperative complication profiles at 1 year.

RESULTS

Seven patients with a median age of 69 years (range, 54-77 years) underwent Yoke procedure and had a median 12-month follow-up (range, 9-56 months). All patients were female and had a median of 2 prior shoulder surgeries (range, 0-13). Of all the patients, the most common comorbidity was osteoporosis (6) followed by rheumatoid arthritis (3). Of the 5 patients who had previous arthroplasty, the most common indications were baseplate failure (4), followed by instability (3) and infection (3). The median visual analog scale score improved from 8 (range, 3-9) to 2 (range, 1-4). The median Simple Shoulder Test improved from 8% (range, 0%-42%) to 33% (range, 17%-83%). The median ASES score improved from 15 (range, 5-38) to 52 (range, 40-78). The median anterior elevation and external rotation improved from 20° (range, 0°-75°) to 100° (range, 40°-145°) and 10° (range, 0°-20°) to 20° (range, 0°-55°), respectively. There was no change in median internal rotation. As of the last follow-up, one patient reported postoperative complications of anterior-superior implant escape, heterotopic ossification, and scapular notching.

CONCLUSION

The Yoke procedure is a promising salvage treatment that can offer patients consistent pain reduction and moderate functional improvements at short-term follow-up. In the setting of poor bone quality and severe glenoid deficiency, glenoid baseplate implantation may not be absolutely necessary for a pain-relieving, functionally acceptable outcome.

Can Distalisation and Lateralisation Shoulder Angles in Reverse Arthroplasty Interfere with the Functional Results in Patients with Rotator Cuff Arthropathy?

Objective:  To evaluate the influence of radiographic values on clinical and functional results in patients treated with reverse arthroplasty for rotator cuff arthropathy (RCA) using a lateralized design. Methods:  A retrospective analysis was performed. Patient demographics were recorded, as well as preoperative and postoperative range of motion. Function was calculated using the Constant-Murley score both before and after the procedure. Pre and postoperative anteroposterior and axial radiographs of the affected shoulder were analysed. In the preoperative images, the following was calculated: acromiohumeral distance (AHD) and lateral humeral offset (LHO). Postoperative measurements included: AHD, LHO, distalization shoulder angle (DSA) and lateralisation shoulder angle (LSA). Linear regression and quadratic regression analysis was performed to determine their degree of association with final functional outcomes. By applying a quadratic regression analysis and ROC curves, the cut-off values were determined with respect to the above-mentioned angles and the positive predictive value was calculated. Results:  The greater anterior elevation (AE) ranges were found with DSA between 40-45° and LSA among 80°- 90°, while better ABD was observed with LSA of 90-100°. Preoperative AHD was correlated to RE (r s :0.47; p:0.049). Postoperative AHD was found to be in a directly proportional relationship with AE (r s :0.49; p:0.03). Postoperative ABD showed an inverse linear regression with preoperative AHD (r s : -0.44, p:0.047). LSA and DSA were inversely related. Conclusion:  We found that a DSA between 40-45° and a LSA of 80-100° could lead to better range of motion regarding AE and ABD in patients with rotator cuff arthropathy treated with RSA.

Glenoid lateralization and subscapularis repair are independent predictive factors of improved internal rotation after reverse shoulder arthroplasty

PURPOSE

Reverse shoulder arthroplasty (RSA) has shown improvement in clinical outcomes for various conditions, although some authors expressed concern about the restoration of active internal rotation (AIR). The current study assesses preoperative and intraoperative predictive factors of AIR in patients having a Grammont-style RSA with a minimum five year follow-up.

METHODS

We conducted a retrospective multicentric study, including patients operated on with a 155° Grammont-style RSA for cuff-related pathology or primary osteoarthritis with posterior subluxation or an associated cuff tear. Patients were clinically evaluated at a minimum of five year follow-up. Patients with previous surgery or those who had a tendon transfer with the RSA were excluded. Demographic parameters, BMI, preoperative notes, and operative reports were obtained from medical records. AIR was graded according to the constant score system from 0 to 10.

RESULTS

A total of 280 shoulders in 269 patients (mean age at surgery, 74.9 ± 5.9 years) met the inclusion criteria and were analyzed. The average follow-up was 8.1 years (range, 5-16 years). Overall, AIR increased from 4.2 (SD 2.5, range 0 to 10) preoperatively to 5.9 (SD 2.6, range 0 to 10) at final follow-up. At the last follow-up, AIR increased in 56% of cases, was unchanged in 26% and decreased in 18%. In 188 shoulders (67%), internal rotation was functional and allowed patients to reach the level of L3 or higher. Multivariable linear regression found the following preoperative clinical factors predictive of worse AIR after RSA: male gender (ß = -1.25 [-2.10; -0.40]; p = 0.0042) and higher values of BMI (ß = -0.085 [-0.17; -0.0065]; p = 0.048). Two surgical factors were associated with better AIR after RSA: glenoid lateralization with BIO-RSA technique (ß = 0.80 [0.043; 1.56]; p = 0.039) and subscapularis repair (ß = 1.16 [0.29; 2.02]; p = 0.0092).

CONCLUSIONS

With a mean of eight year follow-up (5 to 16 years), internal rotation was functional (≥ L3 level) in 67% of operated shoulders after Grammont-style RSA; however, two patients out of ten had decreased AIR after surgery. Male patients and those with higher BMIs had worse AIR, with glenoid lateralization (using the BIO-RSA technique) and subscapularis repair, as they are predictive of increased AIR after RSA.

LEVEL OF EVIDENCE

Case series, Level IV.

Lateralization and distalization shoulder angles do not predict outcomes in reverse shoulder arthroplasty for cuff tear arthropathy

BACKGROUND

In reverse shoulder arthroplasty (RSA), there are a plethora of measurements regarding implant lateralization and distalization to optimize the center of rotation. Two specific measurements known as the "lateralization shoulder angle" (LSA) and "distalization shoulder angle" (DSA) have been the recent focus of studies to assess their association with RSA and postoperative function. The aim of this study was to evaluate the prognostic clinical value of the LSA and DSA in a large cohort of patients with cuff tear arthropathy (CTA) who were treated with different RSA systems.

METHODS

Two local shoulder arthroplasty registries were reviewed for all RSA patients documented to have undergone a radiologic assessment and complete 2-year follow-up examination. The main inclusion criterion was primary RSA in patients with CTA. Patients with either a complete teres minor tear, os acromiale, or acromial stress fracture reported between the time of surgery and the 24-month follow-up were excluded. Five RSA implant systems with 4 neck-shaft angles (NSAs) were assessed. The Constant score, Subjective Shoulder Value, and range of motion at 2 years were correlated with both the LSA and DSA assessed on 6-month anteroposterior radiographs. Linear and parabolic univariable regressions were calculated for both shoulder angles, for each prosthesis system, and for the entire patient cohort.

RESULTS

Between May 2006 and November 2019, there were a total of 630 CTA patients who had undergone primary RSA. Of this large cohort of patients, 270 were treated with the Promos Reverse prosthesis system (NSA, 155°); 44, Aequalis Reversed II (NSA, 155°); 62, Lima SMR Reverse (NSA, 150°); 25, Aequalis Ascend Flex (NSA, 145°); and 229, Univers Revers (NSA, 135°). The mean LSA was 78° (standard deviation [SD], 10°; range, 6°-107°), and the mean DSA was 51° (SD, 10°; range, 7°-91°). The average Constant score at 24 months' follow-up was 68.1 points (SD, 13 points; range, 13-96 points). Neither the linear nor parabolic regression calculations for the LSA or DSA revealed significant associations with any of the clinical outcomes.

CONCLUSION

Different patients may achieve different clinical outcomes despite having identical LSA and DSA values. There is no association between angular radiographic measurements and 2-year functional outcomes after RSA.

Influence of Lateralization and Distalization on Joint Function after Primary Reverse Total Shoulder Arthroplasty

The purpose of this study was to investigate how lateralization shoulder angle (LSA) and distalization shoulder angle (DSA) are related to clinical and kinematic outcomes after reverse total shoulder arthroplasty. Thirty-three patients were evaluated at least six months postoperatively. The Single Assessment Numeric Evaluation (SANE), Constant Murley Score (CMS), Simple Shoulder Test (SST), and Visual Analogue Scale (VAS) were used. Shoulder kinematics was evaluated with a stereophotogrammetric system. LSA and DSA inter-rater reliability was analysed through the interclass correlation coefficient (ICC). Stepwise forward linear regression analysis was conducted between LSA and DSA with clinical scales and kinematic measures, between which a correlation analysis was conducted. The inter-rater reliability for LSA (mean ICC = 0.93) and DSA (mean ICC = 0.97) results were good to excellent. Greater LSA values were associated with higher peaks of internal rotation (p = 0.012, R2 = 0.188) and range of motion (ROM) (p = 0.037, R2 = 0.133). SANE (p = 0.009), CMS (p = 0.031), and SST (0.026) were positively correlated to external rotation, while VAS (p = 0.020) was negatively related. Abduction peaks were positively related to CMS (p = 0.011) and SANE (p = 0.037), as well as abduction ROM (SANE, p = 0.031; CMS, p = 0.014).

The biomechanical effects of acromial fracture angulation in reverse total shoulder arthroplasty

BACKGROUND

The biomechanical changes and treatment guidelines on acromial fracture after reverse shoulder arthroplasty (RSA) are still not well understood. The purpose of our study was to analyze the biomechanical changes with respect to acromial fracture angulation in RSA.

METHODS

RSA was performed on 9 fresh-frozen cadaveric shoulders. An acromial osteotomy was performed on the plane extending from the glenoid surface to simulate an acromion fracture. Four conditions of acromial fracture inferior angulation were evaluated (0°, 10°, 20°, and 30° angulation). The middle deltoid muscle loading origin position was adjusted based on the position of each acromial fracture. The impingement-free angle and capability of the deltoid to produce movement in the abduction and forward flexion planes were measured. The length of the anterior, middle, and posterior deltoid was also analyzed for each acromial fracture angulation.

RESULTS

There was no significant difference in the abduction impingement angle between 0° (61.8° ± 2.9°) and 10° angulation (55.9° ± 2.8°); however, the abduction impingement angle of 20° (49.3° ± 2.9°) significantly decreased from 0° and 30° angulation (44.2° ± 4.6°), and 30° angulation significantly differed from 0° and 10° (P < .01). On forward flexion, 10° (75.6° ± 2.7°), 20° (67.9° ± 3.2°), and 30° angulation (59.8° ± 4.0°) had a significantly decreased impingement-free angle than 0° (84.2° ± 4.3°; P < .01), and 30° angulation had a significantly decreased impingement-free angle than 10°. On analysis of glenohumeral abduction capability, 0° significantly differed (at 12.5, 15.0, 17.5, and 20.0N) from 20° and 30°. For forward flexion capability, 30° angulation showed a significantly smaller value than 0° (15N vs. 20N). As acromial fracture angulation increased, the middle and posterior deltoid muscles of 10°, 20°, and 30° became shorter than those of 0°; however, no significant change was found in the anterior deltoid length.

CONCLUSIONS

In acromial fractures at the plane of glenoid surface, 10° inferior angulation of the acromion did not interfere with abduction and abduction capability. However, 20° and 30° of inferior angulation caused prominent impingement in abduction and forward flexion and reduced abduction capability. In addition, there was a significant difference between 20° and 30°, suggesting that not only the location of the acromion fracture after RSA but also the degree of angulation are important factors for shoulder biomechanics.

Why is female gender associated with poorer clinical outcomes after reverse total shoulder arthroplasty?

INTRODUCTION

There is a lack of gender-specific research after reverse total shoulder arthroplasty (RTSA). Although previous studies have documented worse outcomes in women, a more thorough understanding of why outcomes may differ is needed. We therefore asked: (1) Are there gender-specific differences in preoperative and postoperative clinical scores, complications, surgery-related parameters, and demographics? (2) Is female gender an independent risk factor for poorer clinical outcomes after RTSA? (3) If so, why is female gender associated with poorer outcomes after RTSA?

MATERIALS AND METHODS

Between 2005 and 2019, 987 primary RTSAs were performed in our institution. After exclusion criteria were applied, data of 422 female and 271 male patients were analyzed. Clinical outcomes (absolute/relative Constant Score [a/rCS] and Subjective Shoulder Value [SSV]), complications (intra- and/or postoperative fracture, loosening), surgery-related parameters (indication, implant-related characteristics), and demographics (age, gender, body mass index, and number of previous surgeries) were evaluated. Preoperative and postoperative radiographs were analyzed (critical shoulder angle, deltoid-tuberosity index, reverse shoulder angle, lateralization shoulder angle, and distalization shoulder angle).

RESULTS

Preoperative clinical scores (aCS, rCS, SSV, and pain level) and postoperative clinical outcomes (aCS and rCS) were significantly worse in women. However, the improvement between preoperative and postoperative outcomes was significantly higher in female patients for rCS (P = .037), internal rotation (P < .001), and regarding pain (P < .001). Female patients had a significantly higher number of intraoperative and postoperative fractures (24.9% vs. 11.4%, P < .001). The proportion of female patients with a deltoid-tuberosity index <1.4 was significantly higher than males (P = .01). Female gender was an independent negative predictor for postoperative rCS (P = .047, coefficient -0.084) and pain (P = .017, coefficient -0.574). In addition to female sex per se being a predictive factor of worse outcomes, females were significantly more likely to meet 2 of the 3 most significant predictive factors: (1) significantly worse preoperative clinical scores and (2) higher rate of intra- and/or postoperative fractures.

CONCLUSIONS

Female sex is a very weak, but isolated, negative predictive factor that negatively affects the objective clinical outcome (rCS) after RTSA. However, differences did not reach the minimal clinically important difference, and it is not a predictor for the subjective outcome (SSV). The main reason for the worse outcome in female patients seems to be a combination of higher preoperative disability and higher incidence of fractures. To improve the outcome of women, all measures that contribute to the reduction of perioperative fracture risk should be used.

Factors that affect external rotation following reverse shoulder arthroplasty: a retrospective multi-centre study on 501 shoulders

INTRODUCTION

The purpose of this multi-centre study was to assess external rotation in a large cohort following reverse shoulder arthroplasty (RSA) at a minimum follow-up of 2 years, and identify factors that influence postoperative and/or net-improvement of external rotation.

METHODS

The authors retrospectively reviewed records of 743 RSAs performed between January 2015 and August 2017 by 16 surgeons that participated in a large national society symposium; 193 (25.7%) were lost to follow-up, 16 (2.1%) died, and 33 (4.4%) were revised with implant exchange, which left 501 available for assessment at 2.0-5.5 years. Pre- and post-operative active forward elevation, active external rotation (ER1), active internal rotation (IR1) and constant score (CS) were collected. Regression analyses were performed to determine associations of patient demographics, surgical and implant parameters, rotator cuff muscles status and radiographic angles with ER1.

RESULTS

Multivariable analyses revealed postoperative ER1 decreased with age (β, - 0.35), increased with lateralisation shoulder angle (LSA) (β, 0.26), and was better in shoulders operated by the antero-superior (AS) approach (β, 11.41), but worse in shoulders with absent/atrophic teres minor muscles (β, - 10.06). Net-improvement of ER1 increased with LSA (β, 0.39), was better with inlay stems (β, 8.33) and BIO RSA (β, 6.22), but worse in shoulders operated for primary OA with rotator cuff (RC) tears (β, - 16.26), for secondary OA due to RC tears (β, - 16.06), or for mRCT (β, - 18.96).

CONCLUSIONS

This large multi-centre study revealed that, at a minimum of 2 years following RSA, ER1 improved by 16.1°. Postoperative ER1 was better in shoulders which had normal or hypertrophic teres minor muscles, were operated by the AS approach, or with greater LSA. Net-improvement of ER1 was better in shoulders with inlay stems, with BIO RSA, or with greater LSA, but worse in shoulders with rotator cuff deficiency.

LEVEL OF EVIDENCE

IV.

Predictive factors of acromial fractures following reverse total shoulder arthroplasty: a subgroup analysis of 860 shoulders

Background

Acromion stress fractures (ASF) or scapular spine fractures (SSF) following reverse total shoulder arthroplasty (RTSA) are common complications with impaired clinical outcome. The underlying biomechanical factors remain unclear. The aim of this study was to evaluate basic demographic and radiographic parameters predicting occurrence of different types of ASF/SSF in a large single-center study cohort.

Methods

A total of 860 RTSA (805 patients) with available minimum follow-up of 2 years were implanted between 2005 and 2018 at a tertiary academic center. All RTSA with subsequent ASF/SSF (n = 45 in 43 shoulders [42 patients, 5%]) were identified and classified as Levy I to III. Predictive demographic, surgical, and radiographic factors were evaluated for each subtype and compared to the control group (817 RTSA, 763 patients). The radiographic analysis included critical shoulder angle, lateralization shoulder angle (LSA), distalization shoulder angle (DSA), acromio-humeral distance (ACHD), acromial thickness, deltoid tuberosity index, deltoid length, and center of rotation.

Results

Of the 45 ASF/SSF in 42 patients, 8 were classified as Levy I, 21 as Levy II, and 16 as Levy III. Demographic analysis revealed indication as risk factor for Levy I fractures, higher American Society of Anesthesiologists score as risk for Levy type II fractures and higher age as risk factor for Levy type III fractures. None of the measured radiographic parameters were predictive for occurrence of Levy type I and Levy type II ASF. However, analysis of Levy III SSF revealed a higher postoperative LSA (89° ± 10° vs. 83° ± 9°, P = .015), a lower postoperative DSA (45° ± 8° vs. 53° ± 12°, P = .002), less distalization (ACHD of 33 ± 8 mm vs. 38 ± 10 mm, P = .049), and a more medial center of rotation preoperatively (COR-LA 16 ± 8 mm vs. 12 ± 7 mm, P = .048) as predictive radiographic factors.

Conclusion

The present analysis showed a significant association of higher postoperative LSA, lower DSA, a lower ACHD, and higher age as predictive factor only for Levy type III fractures. Some of these factors can be surgically influenced and this knowledge can be of value for preoperative planning and surgical execution to avoid these complications.

Reverse total shoulder arthroplasty for complex proximal humerus fracture in the elderly: clinical and radiological results

Background

The use of reverse total shoulder arthroplasty (RSA) for the treatment of proximal humeral fractures (PHFs) is steadily increasing. Better clinical outcomes of RSA have been correlated with tuberosity reattachment and healing. The purpose of this study was to evaluate both the clinical and radiological results of reverse shoulder arthroplasty in the management of a proximal humerus fracture in the elderly.

Methods

Retrospective study including 400 consecutive 3-4 part proximal humerus fractures treated with reverse shoulder arthroplasty with a minimum of 12-month follow-up. In all the cases, the greater tuberosity was reattached with a standardized suture technique and a local bone graft. All the patients were assessed at the 12-month follow-up with Constant-Murley Score (CMS). Radiographic healing of the greater tuberosity was noted. Complications and revision rates were reported.

Results

Mean final CMS for this cohort was 82 points. The greater tuberosity healed in anatomic position in 85% of the cases (N = 340), obtaining an average CMS of 85 in these patients. Healing of the greater tuberosity did not occur in 13% of the cases (N = 52) and displacement more than 5 mm occurred in 2% (N = 8) of the patients for an average CMS of 60. All patients scored above 120° in forward elevation with a mean of 150°. Mean active external rotation was 35°. The lateralization shoulder angle had a mean of 91° and the distalization shoulder angle had a mean of 54°. Low-grade scapular notching was reported in <1% of the cases. A total of 60 patients presented failure of healing or displacement of the greater tuberosity. Major complications were reported in nine patients. Of these nine patients, two acquired superficial wound infections, while two had deep shoulder prosthetic infection. Two other patients developed hematomas, one sustained an acromial stress fracture, and two had a stem loosening. There were 4 reoperations.

Conclusion

Reverse shoulder arthroplasty, with the use of a fracture-specific stem, allows an improved rate of greater tuberosity healing and short-term clinical outcomes in the elderly population.

Preoperative Planning for Reverse Shoulder Arthroplasty: Does the Clinical Range of Motion Match the Planned 3D Humeral Displacement?

INTRODUCTION

The functional outcome after reverse shoulder arthroplasty (RSA) is closely linked to how much the humerus shifts because of the implants. While two-dimensional (2D) angle measurements have been used to capture this shift, it can be measured in three dimensions (3D) as the arm change position (ACP). In a previous study, the ACP was measured using 3D preoperative planning software with the passive virtual shoulder range of motion obtained after RSA. The main objective of this study was to evaluate the relationship between the ACP and the actual active shoulder range of motion measured after RSA. The hypothesis was that the ACP and the active clinical range of motion are related such that the ACP is a reliable parameter to guide the preoperative planning of an RSA. The secondary objective was to assess the relationship between 2D and 3D humeral displacement measurements.

MATERIALS AND METHODS

This prospective observational study enrolled 12 patients who underwent RSA and had a minimum follow-up of 2 years. The active range of motion in shoulder flexion, abduction, and internal and external rotation was measured. At the same time, ACP measurements were taken from a reconstructed postoperative CT scan, in addition to the radiographic measurements of humeral lateralization and distalization angles on AP views in neutral rotation.

RESULTS

The mean humeral distalization induced by RSA was 33.3 mm (±3.8 mm). A non-statistically significant increase in shoulder flexion was observed for humeral distalization beyond 38 mm (R² = 0.29, p = 0.07). This "threshold" effect of humeral distalization was also observed for the gains in abduction, as well as internal and external rotations, which seemed better with less than 38 mm or even 35 mm distalization. No statistical correlation was found between the 3D ACP measurements and 2D angle measurements.

CONCLUSION

Excessive humeral distalization seems to be detrimental to joint mobility, especially shoulder flexion. Humeral lateralization and humeral anteriorization measured using the ACP seem to promote better shoulder range of motion, with no threshold effect. These findings could be evidence of tension in the soft tissues around the shoulder joint, which should be taken into consideration during preoperative planning.

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).

Scapulohumeral rhythm in shoulders with reverse shoulder arthroplasty measured with a new portable three-dimensional scapular kinematics assessment system

BACKGROUND

Reverse shoulder arthroplasty (RSA) is a valid and increasingly popular treatment option in eccentric arthrosis and cuff arthropathy. We know that the deltoid is the motor of RSA. However, the role of scapular motion has been poorly documented in the literature. The aim of our study is to analyze and quantify the role of the scapular contribution in the functional outcome of patients undergoing RSA.

MATERIALS AND METHODS

Fourteen patients who underwent primary RSA were included in the study. In all cases, a reverse prosthesis with lateralizing stem was implanted. All patients underwent clinical examination, video recording, and motion analysis. X-ray and postoperative CT examinations were collected to evaluate positioning and any loosening. ShowMotion (NCS Lab srl, Modena, Italy) 3D kinematic tracking system was used to evaluate and measure the scapular motion in 3 planes.

RESULTS

All patients show substantial amount of posterior tilting and lateral rotation starting at 30° in forward elevation. A further difference is the anticipation of the retraction during the range of motion in the RSA side. The contribution of scapular motion in the RSA shoulder was greater than in the healthy shoulder. In patients with bilateral RSA, the contribution of scapular motion was higher in tilting and lateral rotation in the worse shoulder side in terms of range of motion. This means that to compensate for the loss of glenohumeral motion in RSA, more scapula-thoracic motion is needed to obtain the same thoraco-humeral elevation angle.

CONCLUSIONS

In the light of what has been measured, the post-RSA scapular kinematics has typical characteristics that must be achieved in order to obtain a good functional outcome. We can conclude that on the RSA side, the patients anticipate upward rotation both in flexion and abduction. The contribution of the upward rotation to elevation in the RSA group is therefore more significant. In addition to this, to facilitate elevation movements, there is an anticipation of the scapular retraction and a more prominent tilt resulting in different scapular kinematics. The analysis of scapular motion could be useful in the postoperative follow-up of patients undergoing RSA surgery and improve adaptative physiotherapy protocols. It potentially can even be included in future arthroplasty planning systems.

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.

Inlay versus onlay humeral design for reverse shoulder arthroplasty: a systematic review and meta-analysis

BACKGROUND

Since the introduction of the Grammont-style reverse total shoulder arthroplasty, the humeral stem design has been modified with improved clinical outcomes. Two distinct humeral designs have been used extensively: the inlay design, in which the humeral tray is seated within the metaphysis, and the onlay design, in which the humeral tray sits on the metaphysis at the level of the humeral neck cut. The purpose of this systematic review was to determine whether there are differences in clinical outcomes and complication rates between these designs.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used to perform this systematic review. A search of MEDLINE, PubMed, and Embase was performed to identify all studies comparing the clinical results of both humeral designs. Primary outcomes included patient-reported outcome measures, shoulder range of motion, and incidence of complications.

RESULTS

From the 156 identified publications, 12 studies were included in the final review. A total of 1447 patients were included, with a minimum follow-up period of 12 months. At final follow-up, both implants demonstrated significant improvements in comparison to preoperative baseline. On comparison of the inlay vs. onlay groups, the American Shoulder and Elbow Surgeons score was higher in the inlay group (mean difference, 2.53 [95% confidence interval, 0.27-4.78]; P = .03). Postoperative motion, even if statistically greater in the onlay group (differences of 5° in forward flexion [P < .001], 3° in abduction [P = .003], and 4° in external rotation [P < .001]), was not clinically different. On comparison of complications, the inlay group showed more instances of scapular notching (93 of 322 patients vs. 70 of 415 patients; odds ratio, 0.35; P < .001) but fewer scapular spine fractures (26 of 727 patients vs. 21 of 559 patients, P = .09).

DISCUSSION

Inlay and onlay humeral tray designs in reverse total shoulder arthroplasty demonstrate similar clinical improvements postoperatively. Onlay implants have a low rate of scapular notching but a higher rate of scapular spine fracture. Understanding the strengths and weaknesses of the 2 humeral tray designs is important to provide surgeons with options to tailor surgical plans for high-risk patients.

Intra- and Inter-rater Reliability of Postoperative Radiographic Analysis of Reverse Shoulder Arthroplasty in 49 Shoulders After Proximal Humerus Fracture

Introduction

The lateralization shoulder angle (LSA), the distalization shoulder angle (DSA) and the new "pentagon" concept are tools used in scheduled shoulder surgery to evaluate the positioning of reverse shoulder arthroplasty (RSA) implants. There is no information on the intra- and inter-rater reliability of these tools in the context of RSA for a proximal humerus fracture. The first hypothesis was the high reliability of the intra- and inter-rater analysis of the LSA and DSA angles. The second hypothesis was the reproductibility of the pentagon based on LSA and DSA analysis.

Methods

Forty-nine patients were evaluated retrospectively with a minimum of 2 years radiological follow-up after RSA surgery. Tuberosity healing was evaluated using an AP radiograph of the shoulder and their location analyzed within the said "pentagon" defined by the LSA/DSA angles and the maximum lengthening recommended.

Results

The intra-rater analysis found strong to an almost perfect agreement for the LSA and DSA. The agreement was moderate to strong for the pentagon. The inter-rater analysis found a fair agreement for the LSA and moderate agreement for the DSA and pentagon.

Conclusion

The LSA/DSA is used in patients undergoing RSA for glenohumeral OA. In this context, the tuberosities were intact and certain complications inherent to RSA for humeral fracture were not present. The population studied here (RSA after fracture) creates an interpretation bias due to the difficulty in analyzing tuberosity position.

Level of Evidence

4, retrospective study.

Comparative study of 145° onlay curved stem versus 155° inlay straight stem reverse shoulder arthroplasty: clinical and radiographic results with a minimum 2-year follow-up

BACKGROUND

Lateralized onlay reverse shoulder arthroplasty (RSA) is designed to ensure better clinical functional recovery and lower rate of complications compared with Grammont medialized inlay RSA. The purpose of the present study was to compare the clinical and radiographic outcomes between these 2 different designs.

METHODS

Eighty-five consecutive patients who underwent RSA were retrospectively analyzed. Nine patients were lost to follow-up, 34 received a curved onlay with a 145° neck-shaft angle (Ascend Flex group), and 42 received a long straight inlay stem with a 155° neck-shaft angle (Delta Xtend group). Patients were reviewed at an average follow-up of 46.8 ± 13.2 months (Ascend Flex group) and 36 ± 10.8 months (Delta Xtend group). Clinical outcome measures included active range of motion, strength, visual analog scale, Constant-Murley score, and the American Shoulder and Elbow Surgeons score. Radiographic evaluation at the final follow-up was performed to assess scapular notching, stress shielding, acromial or scapular fractures, heterotopic ossification, and radiolucent lines or implant loosening.

RESULTS

No differences emerged between the 2 groups in terms of visual analog scale, American Shoulder and Elbow Surgeons and Constant-Murley scores, pain, function, strength, mobility, active forward elevation, active internal rotation, active external rotation at 0° and 90° of abduction, abduction, forward elevation, and external rotation strength (P = n.s.). Statistically superior active abduction was observed in the Delta Xtend group (P = .0017). Scapular notching was observed in 12 shoulders (35.2%) in the Ascend Flex group (a grade 1) and in 10 shoulders (23.8%) in the Delta Xtend group (P = n.s.). No differences emerged between the 2 groups in terms of humeral or glenoid radiolucency (P = n.s.). Higher rate of humeral stress shielding rate was observed in the Ascend flex cohort (P = n.s.).

CONCLUSIONS

No statistically significant difference emerged between the 145° onlay curved stem vs. the 155° inlay straight stem according to most of the evaluated parameters. Statistically superior active abduction was observed in the 155° group although it did not affect patients' satisfaction.

Which lateralization designed prosthesis of reverse total shoulder arthroplasty (glenoid-based lateralization vs humerus-based lateralization) would be better? Network Meta-analysis

PURPOSE

To demonstrate the differences between outcomes and complications after reverse total shoulder arthroplasty (rTSA), according to the types of lateralized prosthesis designs: glenoid-based lateralization (LG) and humerus-based lateralization (LH).

METHODS

PubMed, Embase, and the Cochrane Library databases were systematically searched for studies published before 1 April 2021, using the PRISMA guidelines. A network meta-analysis was applied for indirect comparison, incorporating studies including medialized or conventional Grammont prosthesis and each lateralized prosthesis (LG vs control and LH vs control). Out of 1,989 screened studies, 11 studies were included to compare functional scores, range of motion (ROM), radiologic outcomes, and revision rates. In addition, six articles from the included studies, which had repaired subscapularis after rTSA were analyzed to exclude the potential influence of subscapularis repair on the outcomes. The data were pooled using a random-effects model. The pooled estimates of the mean differences (MDs) and 95% confidence intervals (CIs) were calculated for continuous data, while dichotomous data were analyzed using the pooled relative risk (RR) and their 95% CIs.

RESULTS

The ROM, complications, and functional scores were similar between the two groups. In subgroup analysis of 6 studies involving concomitant subscapularis repair, the LH group showed higher American Shoulder and Elbow Surgeons (ASES) scores and Constant scores than the control group. Regarding the ROM, LH group showed better forward elevation than the LG group (LH vs LG: MD 10.07, 95% CI -9.05-29.19).

CONCLUSION

Overall, the outcomes and occurrence of complications were not significantly different between the two lateralized prosthesis groups. However, when the subscapularis was repaired, LH prosthesis seems to be more suitable to obtain a better ASES score and ROM.

LEVEL OF EVIDENCE

Level III, network meta-analysis.

Midterm clinical outcome of uncemented short-stem reversed shoulder arthroplasty

INTRODUCTION

While the incidence of reverse total shoulder arthroplasty (rTSA) is increasing constantly, newer implants with designs other than the classic Grammont geometry are gaining importance. More anatomic inclination angles and lateralization are supposed to have a positive impact on clinical results and complication rates. Presentation of midterm results therefore is important to support these assumptions. The aim of this study was to report the midterm clinical outcome of primary rTSA with an uncemented humeral short-stem prosthesis (USSP) with a humeral inclination angle of 145° and the analysis of different variables on the outcome.

METHODS

This is a retrospective study of all patients with primary rTSA using an USSP and a combined humeral inclination angle of 145° (Ascend™ flex, Stryker) with a minimum clinical follow-up of 2 years. The implant combines a 132.5° inclination for the humeral stem with an additional 12.5° for the polyethylene inlay. Primary outcomes were patient-reported outcome measures: ASES score, simple shoulder test (SST) and subjective shoulder value (SSV). Secondary outcomes were complication and revision rates. We analyzed different variables: preoperatively gender, age, indication for surgery and status of rotator cuff. Also, the glenoid morphology was classified according to Walch and a proximal humerus cortical bone thickness measurement (CBT avg) of 6 mm was used as a threshold for osteoporosis. Postoperatively, we analyzed different radiologic parameters: filling ratio, distalization and lateralization angles according to Boutsiadis.

RESULTS

A total of 84 out of 99 (85%) patients with a mean FU of 46.7 months (range 24-80 months) could be included: 62 women and 22 men with a mean age of 74.7 years. Mean ASES score significantly increased from 47 preoperatively to 85.8 at the last follow-up (p = 0.001). The postoperative SST reached an average of 65.3 and the mean SSV was 83%. None of the variable parameters analyzed could be identified as a risk factor for a lower outcome defined as a SSV < 70. Three patients (3.6%) had a complication: one incomplete lower plexus lesion, one dislocation and one major hematoma. Surgical revision was needed in two cases (2.4%).

CONCLUSION

The midterm clinical outcome of primary reverse total shoulder arthroplasty (rTSA) with an uncemented humeral short stem and a humeral inclination angle of 145° showed good-to-excellent results with a low complication and revision rate independent from a wide range of pre- and postoperative variables. PROMs are comparable to those reported for anatomic TSA with a low complication rate, different to historical studies especially with the Grammont design.

LEVEL OF EVIDENCE

Treatment study, Level IV.

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.

Humeral offset as a predictor of outcomes after reverse shoulder arthroplasty

INTRODUCTION

The Grammont-style reverse shoulder arthroplasty (RSA) relies on medialization and distalization of the shoulder center of rotation. Lateralized designs have recently gained popularity. The amount of lateralization, however, remains a controversial topic. The purpose of this study was to correlate the change in humeral offset (HO) with outcomes and complications following RSA. We hypothesized that a lateralized HO following RSA would be associated with improved range of motion (ROM), better patient-reported outcomes (PROs), and fewer complications.

MATERIALS AND METHODS

A consecutive series of 104 patients (109 shoulders) was retrospectively evaluated. All patients underwent primary RSA by 2 shoulder and elbow fellowship-trained orthopedic surgeons at 2 different centers. Inclusion criteria was a primary RSA with at least 1-year follow-up. All patients had the HO measured on a preoperative and a postoperative Grashey radiograph, and the change in HO was calculated (ΔHO = _PostHO-_PreHO). A negative value was defined as a medialized HO and a positive value as a lateralized HO. ROM and primary outcomes, including forward elevation (FE), external rotation (ER), internal rotation (IR), Subjective Shoulder Value (SSV), and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, were collected. Complications and revisions were also reported.

RESULTS

The mean age was 72 years with a mean follow-up of 22.3 months. The average FE (92° vs. 148°), ER (34° vs. 44°), SSV (35% vs. 87%), and ASES score (37.2 vs. 81.2) increased significantly (all P < .01) compared with preoperative values. The HO was medialized postoperatively in 63 shoulders and lateralized in 46 shoulders. No statistically significant differences in the mean values for postoperative FE (147° vs. 146°, P = .892), ER (43° vs. 45°, P = .582), IR (L3 vs. L3, P = .852), SSV (88% vs. 85%, P = .476), and ASES score (81.3 vs. 81.1, P = .961) were found between the groups. However, there was significantly more improvement in ER in the lateralized HO cohort than the medialized cohort (16° vs. 7°, P = .033). Six shoulders, 5 medialized and 1 lateralized HO, demonstrated scapular notching and remained asymptomatic. Five shoulders, 4 medialized and 1 lateralized HO, experienced at least 1 instability incident, and 2 shoulders with medialized HO had an acromion/scapular spine fracture. Overall, 2 shoulders with medialized HO underwent revision surgery because of instability.

CONCLUSIONS

Although RSA provides significant improvement in ROM and PROs regardless of postoperative HO, restoring baseline HO or lateralization beyond baseline may be favorable for improving ER and decreasing complications following RSA.

Incidence, radiographic predictors, and clinical outcome of acromial stress reaction and acromial fractures in reverse total shoulder arthroplasty

BACKGROUND

Acromial and scapular spine fractures (ASFs) are known complications following implantation of reverse total shoulder arthroplasty (RTSA). The entity of acromial stress reaction (ASR) without fracture has recently been described. The purpose of this study was to analyze the incidence, radiographic predictors, treatment options, healing rates, and clinical outcomes of ASF and ASR compared with a control group.

METHODS

A total of 854 primary RTSAs were implanted between 2005 and 2018 in a single shoulder unit of a tertiary referral hospital and retrospectively reviewed for the incidence of ASF and ASR. ASR was defined as pain at the acromion or scapular spine after fracture exclusion on computed tomography scans. The ASF group was matched to a control group. Preoperative and postoperative radiographs were analyzed for radiographic predictors of ASF or ASR. The impact of ASF and ASR, operative vs. nonoperative treatment, and fracture union on clinical outcomes (Constant-Murley score [CS], Subjective Shoulder Value [SSV], and range of motion) with a minimum follow-up period of 2 years was analyzed.

RESULTS

A total of 46 ASFs (5.4%) in 44 patients and 44 ASRs (5.2%) in 43 patients were detected at a mean of 16 ± 24 months and 20 ± 23 months postoperatively, respectively. Predictive radiographic factors were an increased critical shoulder angle and lateralization shoulder angle. The overall union rate was 55% (22 of 40) but was significantly higher following operative treatment (9 of 11, 82%) compared with nonoperative treatment (13 of 29, 45%). Patients with ASF or ASR demonstrated inferior clinical outcomes (CS, 44 ± 21 and 48 ± 18; SSV, 52% ± 25% and 57% ± 27%) compared with the control group (CS, 66 ± 14; SSV, 82% ± 22%) independent of bony union or treatment at a mean of 59 ± 33 months (ASF) and 61 ± 38 months (ASR).

CONCLUSION

ASF and ASR are frequent complications following RTSA implantation with similar poor clinical outcome measures. The healing rate was shown to be much higher with a surgical approach. Nevertheless, fracture consolidation does not result in better clinical outcomes compared with nonunion.

The arm change position: Additional information for optimizing range of motion after reverse shoulder arthroplasty

INTRODUCTION

The arm change position (ACP) is a new parameter for evaluating the humerus' 3D displacement following reverse shoulder arthroplasty (RSA) during 3D pre operative planning. The purpose of this study was to analyze the relationship between ACP variations after RSA and simulated passive joint mobility. The assumption is that the ACP will to help optimize the passive joint mobility of a RSA implant.

METHODS

In 30 degenerative shoulders, four shoulder surgeons planned a RSA with virtual motion analysis. After this analysis, each plan was revised to optimize the range of motion. Relationships between the differences in movement amplitude and the differences in ACP were evaluated.

RESULTS

Arm lengthening and humerus lateralization were significantly associated with better joint mobility in all three planes (frontal, sagittal and axial). They were equally important for improving external rotation, extension, flexion and adduction. Anterior displacement of the humerus improved both internal and external rotation.

DISCUSSION

The ACP is a useful preoperative planning parameter for RSA. It could help with selecting the best implant combination, as well as determining their position, in order to optimize the simulated passive mobility relative to humerus displacement after RSA. To validate the value of the ACP in clinical practice, a prospective study is needed in which the postoperative joint mobility is measured in vivo as a function of the ACP.

LEVEL OF EVIDENCE

III, case control study.

Lateralized glenosphere reverse shoulder arthroplasty: inlay and onlay designs have similar clinical outcomes in patients with glenohumeral osteoarthritis

BACKGROUND

Whether or how the position of the humeral tray (inlay or onlay) in reverse shoulder arthroplasty (RSA) affects outcomes is unclear. Our goal was to compare the clinical and radiographic results of RSA systems with inlay vs. onlay designs but with similar neck shaft angles (NSAs) and lateralized glenospheres.

METHODS

We screened the institutional database at our tertiary academic center for patients who underwent primary RSA (with a lateralized glenosphere and a 135° NSA) from 2009 through 2017. The indication for surgery was glenohumeral osteoarthritis with glenoid bone loss (Walch classification A2, B2, B3, or C) and an intact rotator cuff. All patients were followed for a minimum of 2 years (mean, 47 months; range, 24-123 months). The humeral tray design was inlay for 79 patients and onlay for 71. All patients underwent preoperative and postoperative evaluations, including physical examination, radiography, and patient-reported outcome measures (visual analog scale for pain, American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and Western Ontario Osteoarthritis of the Shoulder index).

RESULTS

Compared with preoperative values, both groups achieved minimal clinically important differences in range of motion and patient-reported outcomes at the final follow-up. We found no significant differences between groups in any of these measures at the final follow-up. Rates of revision (inlay, 3.8% vs. onlay, 1.4%), scapular notching (inlay, 5.1% vs. onlay, 7.0%), acromial stress fracture (inlay, 0% vs. onlay, 2.8%), and tuberosity resorption (inlay, 25% vs. onlay, 27%) were not significantly different between groups (all, P > .05).

CONCLUSION

For patients with glenohumeral osteoarthritis with glenoid bone loss and an intact rotator cuff who underwent RSA using a lateralized glenosphere prosthesis with a 135° NSA, there were no significant differences between the inlay and onlay groups for range of motion, patient-reported outcomes, or complication rates. These findings are limited to this off-label indication for RSA.

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.

Radiographic parameters associated with excellent versus poor range of motion outcomes following reverse shoulder arthroplasty

BACKGROUND

The purpose was to evaluate the relationship of component size and position to postoperative range of motion following reverse shoulder arthroplasty. The hypothesis was that increased lateralization, larger glenospheres, and a decreased acromiohumeral distance would be associated with excellent postoperative range of motion.

METHODS

A retrospective multicenter study was performed at a minimum of one year postoperatively on 160 patients who underwent primary reverse shoulder arthroplasty with a 135° humeral component. Outcomes were stratified based on postoperative forward flexion and external rotation into excellent (n = 42), defined as forward flexion >140° and external rotation > 30°, or poor (n = 36), defined as forward flexion <100° and external rotation < 15°. Radiographic measurements and component features were compared between the two groups.

RESULTS

A larger glenosphere size was associated with an excellent outcome (p = 0.009). A 2-mm posterior offset humeral cup (p = 0.012) and an increased inferior glenosphere overhang (3.1 mm vs 1.4 mm; p = 0.002) were also associated with excellent outcomes. Humeral lateralization and distalization were not associated with an excellent outcome.Conclusion: Larger glenosphere size and inferior positioning as well as posterior humeral offset are associated with improved postoperative range of motion following reverse shoulder arthroplasty.

LEVEL OF EVIDENCE

Level 3, retrospective comparative study.

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.

Reverse Shoulder Arthroplasty Humeral Lateralisation: A Systematic Review

Different studies on reverse shoulder arthroplasty (RSA) have proposed changes to the humeral design to lateralise the humeral centre of rotation (COR), with humeral inclination to 135 or 145 from 155 degrees or to switch to onlay humeral trays from inlay design; with both having also been used in combination. There have been many studies and systematic reviews to show the difference in outcomes and complications to the variations in glenoid design but to date, there have been no systematic studies to compare different humeral inclinations for RSA implants.

Searches using keywords were used in common medical search engines in a systematic fashion. The article was reviewed for the class of evidence and bias, summarised and compared in meta-analysis. Inclusion criteria included studies on adults with RSA that compared lateralised humeral implants to medialised.

The search produced 349 articles; of these, we identified nine studies that met the inclusion criteria. Our review identified a total of 562 patients who had been included in studies directly comparing lateralised humerus to a more medial design. Meta-analysis showed a significantly reduced risk of scapular notching in lateralised humerus compared to the standard medialised component. The external rotation range of motion in the lateralised group was statistically significant.

The improvement in scapular notching and gain in the range of motion without any apparent downside in the form of reduced patient-reported outcome measures or complications suggest a lateralised humeral component is superior to the more medialised design in RSA. A large RCT with a longer-term follow-up is needed to confirm whether there is clinically significant benefit from the lateralisation of the humerus.

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.

Similar optimal distalization and lateralization angles can be achieved with different reverse shoulder arthroplasty implant designs

Background

Optimal postoperative distalization (DSA) and lateralization (LSA) shoulder angles have been described as radiological measurements correlated with function after reverse shoulder arthroplasty (RSA). The proposed optimal values are DSA between 40° and 65° and LSA between 75° and 95°; however, whether these values can be reached with different implant designs is unclear.

Aim

To determine which RSA implant could achieve higher rates of optimal DSA and LSA, to determine any association between each implant and optimal DSA and LSA, and to assess the correlation of the preoperative critical shoulder angle (CSA) and acromial index (AI) with the DSA and LSA.

Methods

This was a retrospective comparative study of all patients who underwent primary RSA for rotator cuff arthropathy. Three RSA implant designs were included, based on which patients were divided into three groups: group 1 (FH Arrow™; 16 patients) comprised onlay implants with a 135° neck-shaft angle (NSA); group 2 (Biomet Comprehensive™; 20 patients) comprised onlay implants with a 147° NSA; group 3 (Mathys Affinis™; 15 patients) comprised inlay implants with a 155° NSA. The AI and CSA were measured on preoperative radiographs. The DSA and LSA were measured on true AP postoperative radiographs.

Results

The mean DSAs were 44°, 46°, and 46° (P = 0.671) and the mean LSAs were 92°, 91°, and 82° for groups 1, 2, and 3, respectively (P = 0.003). Group 3 had lower LSA than groups 1 (-10°; P = 0.005) and 2 (-9°; P = 0.002). Optimal DSA and LSA were achieved in 71% and 73% of all arthroplasties, respectively. No association between implant designs and achieving an optimal DSA or LSA was observed. None of the implant designs had DSA >65°. The most common cause of failure to reach an optimal LSA in onlay implants was a combination of LSA >95° and DSA <40°. The most common cause of failure in group 3 was DSA <40°. The DSA was negatively correlated with the AI (-0.384; P = 0.006) and CSA (-0.305; P = 0.033). No correlation was observed between the LSA and AI (P = 0.312) or CSA (P = 0.137).

Conclusion

The LSA is lower with the Mathys Affinis™ implant than with the Biomet Comprehensive™ and FH Arrow™ implants; however, most LSAs are in the optimal ranges, and no association is observed between different implant designs and optimal DSA and LSA. Implant design, CSA, and AI should be considered during preoperative planning to achieve optimal DSA and LSA.

Clinical and Radiological Outcomes in Reverse Total Shoulder Arthroplasty by Inclination Angle With a Modular Prosthesis

The influence of the humeral inclination in reverse total shoulder arthroplasty (RTSA) is not well understood. The purpose of this study was to determine outcomes and complications after RTSA with an inclination of 135° or 155° in a modular prosthesis. American Shoulder and Elbow Surgeons (ASES), visual analog scale (VAS), Single Assessment Numeric Evaluation (SANE), and Simple Shoulder Test (SST) scores, as well as forward elevation (FE), abduction (ABD), and external rotation (ER), were assessed after a minimum 2-year follow-up. Scapular notching and radiolucency were assessed according to Sirveaux and Lévigne. A total of 121 patients with a mean age of 69.7±7.3 years were evaluated after a mean of 36.5±8 months. The inclination was set to 135° in 80.2% and to 155° in 19.8% of patients. There was no significant difference between the groups for ASES, VAS, SANE, and SST scores. The FE (P=.022) and ABD (P=.002) were significantly higher for the 155° inclination group. Complication rates were not significantly different between the groups. Scapular notching was significantly more common with a 155° inclination (P=.01), whereas humeral radiolucency was not correlated. All outcome scores improved significantly from pre- to postoperative (P≤.001). Reverse total shoulder arthroplasty leads to significant improvements in pain, range of motion, and outcome scores after mid-term follow-up. Overall, the inclination angle does not significantly affect clinical outcomes or the complication rate after RTSA at mid-term follow-up. However, an inclination of 155° shows significantly greater FE and ABD, although it results in a significantly higher rate of scapular notching. Cases with scapular notching are associated with significantly reduced mean ASES scores and ER as well as significantly higher VAS scores. [Orthopedics. 2021;44(4):e527-e533.].

Teres minor muscle hypertrophy is a negative predictor of outcomes after reverse total shoulder arthroplasty: an evaluation of preoperative magnetic resonance imaging and postoperative implant position

BACKGROUND

Predictors of outcomes after reverse total shoulder arthroplasty (rTSA) remain unclear. The purpose of this study was to analyze the impact of preoperative muscle quality and postoperative implant positioning on patient-reported outcomes following rTSA.

METHODS

We evaluated 88 shoulders treated with rTSA in which preoperative magnetic resonance imaging was available. Preoperative muscle quality was evaluated, including fatty infiltration, rotator cuff muscle volume, and total tear size. Postoperative implant position was determined radiographically. The correlation between imaging parameters and the 2-year postoperative American Shoulder and Elbow Surgeons (ASES) score was examined. Multivariate analyses were performed to adjust for confounding factors including patient demographic characteristics and implant position.

RESULTS

Univariate analysis showed that the ASES score was significantly lower in patients with teres minor muscle hypertrophy relative to those with normal muscle (73.3 ± 22.8 vs. 84.2 ± 16.9, P = .02). The functional subscore was significantly lower in patients with grade 2 fatty infiltration of the deltoid muscle relative to those with grade 0 fatty infiltration (26.1 ± 14.6 vs. 34.8 ± 11.6, P = .03). Older age was associated with a higher pain subscore (ρ = 0.32, P = .002). Multivariate analysis demonstrated that teres minor muscle hypertrophy remained a significant independent predictor of the ASES score (β coefficient = 91.3, P = .03).

CONCLUSION

Teres minor muscle hypertrophy is an independent negative predictor of patient-reported outcomes after rTSA.

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.

Radiographic geometry and clinical glenohumeral range of motion after reverse shoulder athroplasty, a retrospective cohort study

Background

The range of motion (ROM) in reverse shoulder arthroplasty (RSA), is mechanically limited by the surrounding bony obstacles especially in abduction and rotation planes. However, the clinical effect of implant positioning, prosthesis design, and individual differences in bone morphology, on ROM is obscure. The aim of this study was to investigate the correlation between radiographic geometry and clinical glenohumeral (GH) ROM after RSA.

Methods

RSA patients operated at Turku University Hospital during 2007–2013 were called for radiological and clinical follow-up. Pre- and postoperative true anteroposterior radiographs were obtained and the positioning of the center of rotation (COR) in relation to the surrounding bony structures was measured. Active and passive shoulder and GH abduction, flexion, internal and external rotation ROM were measured with goniometer. The Constant score (CS) and pain visual analogue scale (VAS) were recorded. The correlation between the radiographically measured parameters and the active and passive ROM and clinical outcome was statistically analyzed.

Results

91 shoulders were available for analyses with a mean follow-up of 38.7 months ± SD 20 (range 12–83) months. 77% of the patients were female, the mean age was 73 (SD 9) years. The mean angle between the line of supraspinatus fossa, and the line between COR and lateral edge of the acromion (α-angle) was 127° (SD 14) and the mean angle between the lines from lateral edge of the acromion to COR, and from there to the superior edge of the greater tubercle (β-angle) was 54° (SD 11). The mean active shoulder flexion at follow-up was 118° (SD 26), abduction 104° (SD 32), external rotation 41° (SD 22), internal rotation 77° (SD 21). The mean passive GH flexion was 80° (SD 19), abduction 67° (SD 15), external rotation 31° (SD 16) and internal rotation 34° (SD 14). The mean Constant score at follow-up was 53 (SD 18) and pain VAS 2 (SD 3). The positioning of the radiographically measured COR did not statistically significantly correlate with the ROM or clinical outcome scores.

Conclusions

Postoperative radiographically measured two-dimensional geometry and positioning of the COR does not significantly correlate with the glenohumeral range of motion or clinical results after RSA.

Level of evidence

Level 3, retrospective cohort study