Impact of glenosphere size on clinical outcomes after reverse total shoulder arthroplasty: an analysis of 297 shoulders

Does matching glenosphere size to patient height improve outcomes following reverse total shoulder arthroplasty?

Introduction

Optimal biomechanics in reverse total shoulder arthroplasty (rTSA) are still a topic of debate. Although larger glenospheres have been linked with a theoretical improvement in the range of movement, results from clinical studies are mixed. We hypothesised that matching glenosphere diameter to patient height would result in greater improvements in post-operative range of motion (ROM) and patient-reported outcomes (PROMs).

Methods

An international database of rTSAs was analysed. After exclusions, 3318 rTSA patients were classified as short (<158 cm), average (158-173 cm) or tall(>173 cm). Outcomes were stratified for glenosphere size (small≤38 mm, large≥40 mm). Results were compared preoperatively and at 2 years.

Results

In short patients glenosphere diameter had no statistically significant impact on the degree of post-operative improvement for any ROM or PROM. Average height patients treated with small glenospheres had significantly more improvement in internal rotation (1.3 vs 1.0, p = 0.01), VAS pain (5.3 vs 4.8, p = 0.002), American Shoulder and Elbow Surgeons (47.8 vs 45.2, p = 0.03) and Shoulder Arthroplasty Smart (30.9 vs 28.2, p = 0.01) but significantly less improvement in constant score (31.7 vs 35.3, p = 0.009). Tall patients treated with small glenospheres had significantly more improvement in external rotation (21.2 vs 16.4, p = 0.01) and VAS pain scores (4.7 vs 4.3, p = 0.04).

Conclusions

While most significant differences favoured small glenospheres, the magnitude of these differences was small. Overall, patients of all heights can expect similar clinical improvements irrespective of glenosphere size.

Comparison of the clinical outcomes and temporal changes between superior capsular reconstruction and reverse total shoulder arthroplasty in patients with irreparable rotator cuff tear without osteoarthritic change

BACKGROUND

Superior capsular reconstruction (SCR) and reverse total shoulder arthroplasty (rTSA) are widely performed in patients with irreparable rotator cuff tears, including pseudoparalytic shoulder (PPS), and have shown positive clinical outcomes. However, limited studies have compared these 2 in terms of functional recovery in patients with PPS without osteoarthritic change. Thus, this study aimed to compare the clinical outcomes and to clarify the characteristics and differences in temporal changes among patients who underwent either rTSA or SCR using tensor fascia lata for PPS due to irreparable rotator cuff tear without osteoarthritic change (Hamada grade ≤3).

METHODS

We enrolled a total of 39 patients who underwent SCR (n = 20) or rTSA (n = 19 cases) with a follow-up period of 2 years. All patients were followed up at 2, 3, 4, 5, 6, 8, 10, 12, and 24 months postoperatively. Preoperative and postoperative range of motion (ROM), American Shoulder and Elbow Surgeons scores, and temporal changes in ROMs were compared between the 2 groups.

RESULTS

The SCR group had significantly better ROM than the rTSA group in flexion (146° ± 34° vs. 132° ± 23°, P = .022), abduction (147° ± 36° vs. 130° ± 23°, P = .0092), internal rotation (11 ± 3 Th10 vs. 6 ± 3 L3, P < .001), and American Shoulder and Elbow Surgeons score (84.1 ± 13.8 vs. 80.1 ± 6.1, P = .0096). While the rTSA group achieved 100° in flexion and abduction after 3 months postoperatively, the SCR group took approximately 5 months. However, the SCR group exceeded the rTSA group in flexion and abduction at six months postoperatively. In the SCR group, some patients with irreparable subscapularis tendon tears could not achieve 90° shoulder elevation. Both groups showed significant improvements in shoulder flexion and abduction compared to the preoperative state (P < .001).

CONCLUSION

Although SCR requires a longer rehabilitation period, it provides similar outcomes to rTSA after two years for nonosteoarthritic, irreparable cuff tears with pseudoparalysis.

Gender bias in glenosphere size selection in reverse total shoulder arthroplasty: Glenoid size correlates with height and weight, not just gender

Background

Optimal glenosphere selection is critical for successful outcomes following reverse total shoulder arthroplasty (rTSA). This study primarily aimed to determine patient-specific variables associated with dimensions of native glenoid anatomy. Secondarily, we aimed to determine the distribution of glenosphere sizes selected in male and female patients with similar-sized glenoids.

Methods

Computed tomography scans from patients undergoing rTSA with a diagnosis of cuff arthropathy or irreparable cuff tears were included for analysis. Variables collected included the following: age, gender, height, weight, and glenosphere size. Glenoid dimensions were measured, and interobserver reliability was calculated. Correlation coefficients were calculated for all variables. Multivariate predictive regression models were utilized to determine correlations between patient variables and glenoid width and height.

Results

One hundred and eighteen patients (46% male, 54% female) were included for analysis. Taller and male patients were significantly associated with increased glenoid height (P = .0096 and P = .0003, respectively). Females, shorter patients, and patients with decreased body weight were significantly associated with decreased glenoid width (P = .01, P < .0001, and P = .01, respectively). Through stepwise selection, patient height was most strongly associated with glenoid width (P < .0001). For glenoid widths between 25 and 30 mm, there was a significant variation in selected glenosphere sizes based on gender (P < .0001).

Discussion

Patient gender and height are significantly associated with glenoid height and width. There remains a strong tendency towards gender bias when selecting glenosphere sizes for patients undergoing rTSA with similar-sized glenoids. This data highlights the importance of considering patient height as well as gender when considering glenoid component size in the setting of rTSA.

Lateralized reverse shoulder arthroplasty shows similar scaption kinematics but greater scapular neck-insert distance during external rotation compared to Grammont prosthesis

BACKGROUND

Biomechanical differences between reverse shoulder arthroplasty (RSA) designs, specifically those with larger neck-shaft angles like the Grammont-type prosthesis and those with smaller neck-shaft angles such as lateralized humerus RSAs, have been analyzed in ex vivo studies. However, there are limited data on the differences in in vivo shoulder kinematics between these designs. The purpose of this study was to analyze in vivo kinematics of lateralized humerus RSA during active scaption and external rotation at the side, and to compare them to previously reported data for Grammont-type RSA.

METHODS

Twenty shoulders that underwent RSA using a lateralized onlay prosthesis were included in this study. They consisted of 10 males and 5 females with a mean age of 76 years (range: 69-83). Patients underwent fluoroscopy during active scaption and external rotation at the side at or after postoperative 1 year; additionally, computed tomography was performed to create three-dimensional scapular implant models. Using these fluoroscopic images and three-dimensional models, three-dimensional shoulder kinematics were computed using model-image registration techniques. Scaption kinematics and scapular-neck distance were compared with data from previous studies on Grammont-type RSA, which were analyzed using the same techniques as in this study.

RESULTS

There were no significant differences in scaption kinematics between lateralized humerus and Grammont-type RSA. However, the scapular neck-insert distance during active external rotation at the side was significantly greater in lateralized humerus RSA (3.2-5 mm) than in Grammont-type RSA (approximately 1 mm, P < .001), despite the glenohumeral abduction angles being significantly smaller (P = .03).

CONCLUSION

Lateralized humerus RSA showed similar scaption kinematics to Grammont-type RSA; however, the scapular neck-insert distance during active external rotation at the side was significantly greater in lateralized humerus RSA than in Grammont-type RSA. The greater neck-insert distance may contribute to a lower incidence of scapular notching.

Development, Evolution, and Outcomes of More Anatomical Reverse Shoulder Arthroplasty

Reverse shoulder arthroplasty (RSA) has become a widely used procedure since its introduction in the 1980s, and is currently used to treat a wider range of conditions than its original indication. The original Grammont-style RSA revolutionized shoulder arthroplasty but had several limitations, including scapular notching and reduced rotational motion. This review discusses the evolution of RSA design, particularly the development of a lateralized center of rotation constructs, which aims to improve all the disadvantages associated with the Grammont-style design and more closely reproduce the native anatomy in order to improve patient outcomes in an expanded context of pathologies.

Comparative Study on Postoperative Immobilization in Reverse Total Shoulder Arthroplasty: 4 Weeks vs. 6 Weeks of Immobilization Yields Similar Clinical and Functional Outcomes

Background/Objectives: To investigate clinical and functional outcomes of patients undergoing reverse total shoulder arthroplasty (RTSA) using a rehabilitation protocol of either 4 or 6 weeks of immobilization. Methods: This comparative study analyzed a consecutive patient cohort that underwent RTSA in a single institute from January 2021-February 2023. Patients were assigned to groups according to the duration of postoperative immobilization and were followed up for a minimum of one year. Patient demographics, range of motion (ROM), functional outcomes using the Simple Shoulder Test (SST) and the American Shoulder and Elbow Score (ASES) as well as postoperative complications were recorded. The minimum clinically important difference (MCID) was used to assess whether the differences between the groups in SST, ASES, SWB, and VAS were clinically relevant. Results: Sixty patients met the inclusion criteria (35 patients in the 6-week immobilization group (6 WG) and 25 patients in the 4-week immobilization group (4 WG)) and were available for the total follow-up period. Similar baseline demographics were observed between the groups. Active ROM significantly improved for both groups, with abduction and forward flexion improving the most. In terms of functional outcomes, significant improvement (p < 0.001) was demonstrated for both groups (ASES, SST, VAS, and SWB). However, patients in the 4 WG reached significantly better results in VAS and SWB at 6 weeks and 3 months, as well as in ASES 3 months postoperatively, whereas both groups leveled off at the end of the follow-up period after 1 year. Taking into account the MCID, these differences for ASES at 3 months, as well as VAS and SWB at 6 weeks and 3 months postoperatively, were significant. Surprisingly, there were no differences between the groups over the entire follow-up period in terms of the SST. Conclusions: The author's findings suggest faster clinical recovery at 6 weeks and 3 months in patients undergoing postoperative immobilization of 4 weeks compared to 6 weeks following RTSA. However, clinical and functional outcomes were equal for 4 WG and 6 WG at one year follow up.

Scapulothoracic orientation has a significant influence on the clinical outcome after reverse total shoulder arthroplasty

BACKGROUND

Computer simulation has indicated a significant effect of scapulothoracic orientation and posture on range of motion (ROM) after reverse total shoulder arthroplasty (RTSA). We analyzed this putative effect on the clinical and radiologic outcome post-RTSA.

METHODS

We retrospectively assessed 2-year follow-up data of RTSA patients treated at our clinic between 2008 and 2019. Patients were categorized into posture types A, B, and C based on an established method using scapular internal rotation on preoperative cross-sectional imaging. We compared differences in clinical ROM, pain, Subjective Shoulder Value, Constant Score, Shoulder Pain and Disability Index (SPADI), quality of life (EuroQol-5 Dimensions-5 Level utility index), and radiologic outcomes between posture types using linear regression analyses.

RESULTS

Of 681 included patients, 225 had type A posture, 326 type B, and 130 type C. Baseline group characteristics were comparable, although the type C group had a higher proportion of females (60% [A], 64% [B], 80% [C]) with lower abduction strength (0.7 kg [A], 0.6 kg [B], 0.3 kg [C]) and a slightly higher proportion with a Grammont design RTSA (41% [A], 48% [B], 54% [C]). There were significant adjusted differences in mean (±standard deviation) active flexion (A: 137° ± 21°; B: 136° ± 20°; C: 131° ± 19°) and passive flexion (A: 140° ± 19°; B: 138° ± 19°; C: 134° ± 18°), active (A: 127° ± 26°; B: 125° ± 26°; C: 117° ± 27°) and passive abduction (A: 129° ± 24°; B: 128° ± 25°; C: 121° ± 25°), SPADI (A: 81 ± 18; B: 79 ± 20; C: 73 ± 23), and pain (A: 1.2 ± 1.7; B: 1.6 ± 2.2; C: 1.8 ± 2.4) between posture types at 2 years (P ≤ .035). A higher distalization shoulder angle was associated with better abduction in type C patients (P = .016). Type C patients showed a trend toward a higher complication rate (3.9% vs. 1.1% [A], 3.2% [B]) (P = .067).

CONCLUSIONS

Type C posture influences the 2-year clinical outcome of RTSA patients in terms of worse flexion, abduction, SPADI, and pain. Scapulothoracic orientation and posture should be considered during the patient selection process, preoperative planning, and implantation of an RTSA.

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

Biomechanical Characteristics of Glenosphere Orientation Based on Tilting Angle and Overhang Changes in Reverse Shoulder Arthroplasty

Background

Glenoid position and inclination are important factors in protecting against scapular notching, which is the most common complication that directly affects the longevity of reverse shoulder arthroplasty (RSA). This study aimed to investigate the biomechanical characteristics of glenosphere orientation, comparing neutral tilt, inferior overhang with an eccentric glenosphere at the same placement of baseplate, and inferior tilt after 10° inferior reaming in the lower part of the glenoid in RSA.

Methods

Nine cadaveric shoulders were tested with 5 combinations of customized glenoid components: a centric glenosphere was combined with a standard baseplate (group A); an eccentric glenosphere to provide 4-mm inferior overhang than the centric glenosphere was combined with a standard baseplate (group B); a centric glenosphere was combined with a wedge-shaped baseplate tilted inferiorly by 10° with the same center of rotation (group C); an eccentric glenosphere was attached to a wedge-shaped baseplate (group D); and 10° inferior reaming was performed on the lower part of the glenoid to apply 10° inferior tilt, with a centric glenosphere secured to the standard baseplate for simulation of clinical tilt (group E). Impingement-free angles for adduction, abduction, forward flexion, external rotation, and internal rotation were measured. The capability of the deltoid moment arm for abduction and forward flexion, deltoid length, and geometric analysis for adduction engagement were evaluated.

Results

Compared with neutral tilt, inferior tilt at the same position showed no significant difference in impingement-free angle, moment arm capability, and deltoid length. However, group D resulted in better biomechanical properties than a central position, regardless of inferior tilt. Group E demonstrated a greater range of adduction, internal and external rotation, and higher abduction and forward flexion capability with distalization, compared to corresponding parameters for inferior tilt with a customized wedge-shaped baseplate.

Conclusions

A 10° inferior tilt of the glenosphere, without changing the position of the baseplate, had no benefit in terms of the impingement-free angle and deltoid moment arm. However, an eccentric glenosphere had a significant advantage, regardless of inferior tilt. Inferior tilt through 10° inferior reaming showed better biomechanical results than neutral tilt due to the distalization effect.

Glenosphere Size Does Not Matter in Reverse Total Shoulder Arthroplasty

Objective  There are few studies to date reporting on outcomes following reverse total shoulder arthroplasty with cohorts stratified by glenosphere size. The purpose of this study is to investigate the role that glenosphere size has on postoperative outcomes. Methods  Patients who underwent reverse TSA between 1987 with minimum of 2.0 years of follow-up were included. Patients were stratified into two cohorts based on glenosphere size of 36mm or 40mm. Patients' range of motion, patient-reported outcomes, and radiographic variables (glenoid preoperative morphology, scapular notching, humeral loosening) were evaluated. Results  All measurements of range of motion measurements with the exception of internal rotation saw significant preoperative to postoperative improvements within each cohort. There were no significant differences in postoperative range of motion, ASES, or VAS pain scores across the two cohorts. Overall, forward elevation improved to 134° ± 16° in the 36mm cohort and 133° ± 14° in the 40mm cohort ( p  = 0.47). External rotation improved to 37° ± 13° for 36mm patients and 35° ± 19° for 40mm patients ( p  = 0.58). In the 36mm group, internal rotation increased by 1.3 vertebral levels and 2.3 vertebral levels in the 40mm cohort. At final follow-up, the 36mm cohort had a VAS score of 2 ± 2, ASES score of 66 ± 19, and SST score of 6 ± 3. Similarly, the 40mm cohort had a VAS score of 2 ± 3, ASES score of 77 ± 28, and SST score of 9 ± 3. Conclusions  Reverse TSA provides sustained improvements in range of motion and shoulder function irrespective of glenosphere size. Level of Evidence  III.

Clinical outcomes of anatomic vs. reverse total shoulder arthroplasty in primary osteoarthritis with preoperative external rotation weakness and an intact rotator cuff: a case-control study

BACKGROUND

Anatomic (aTSA) and reverse total shoulder arthroplasty (rTSA) are well-established treatments for patients with primary osteoarthritis and an intact cuff. However, it is unclear whether aTSA or rTSA provides superior outcomes in patients with preoperative external rotation (ER) weakness.

METHODS

A retrospective review of a prospectively collected shoulder arthroplasty database was performed between 2007 and 2020. Patients were excluded for preoperative diagnoses of nerve injury, infection, tumor, or fracture. The analysis included 333 aTSAs and 155 rTSAs performed for primary cuff-intact osteoarthritis with 2-year minimum follow-up. Defining preoperative ER weakness as strength <3.3 kilograms (7.2 pounds), 3 cohorts were created and matched: (1) weak aTSAs (n = 74) vs. normal aTSAs (n = 74), (2) weak rTSAs (n = 38) vs. normal rTSAs (n = 38), and (3) weak rTSAs (n = 60) vs. weak aTSAs (n = 60). We compared range of motion, outcome scores, strength, complications, and revision rates at the latest follow-up.

RESULTS

Despite weak aTSAs having poorer preoperative strength in forward elevation and ER (P < .001), neither of these deficits persisted postoperatively compared with the normal cohort. Likewise, weak rTSAs had poorer preoperative strength in forward elevation and ER, overhead motion, and Constant, Shoulder Pain and Disability Index, and University of California, Los Angeles scores (P < .029). However, no statistically significant differences were found between preoperatively weak and normal rTSAs. When comparing weak aTSA vs. weak rTSA, no differences were found in preoperative and postoperative outcomes, proportion of patients achieving the minimal clinically important difference and substantial clinical benefit, and complication and rate of revision surgery.

CONCLUSIONS

In preoperatively weak patients with cuff-intact primary osteoarthritis, aTSA leads to similar postoperative strength, range of motion, and outcome scores compared with patients with normal preoperative strength, indicating that preoperative weakness does not preclude aTSA use. Furthermore, patients who were preoperatively weak in ER demonstrated improved postoperative rotational motion after undergoing aTSA and rTSA, with both groups achieving the minimal clinically important difference and substantial clinical benefit at similar rates.

The Influence of Component Design and Positioning on Soft-Tissue Tensioning and Complications in Reverse Total Shoulder Arthroplasty: A Review

» Reverse total shoulder arthroplasty was designed to function in the rotator cuff deficient shoulder by adjusting the glenohumeral center of rotation (COR) to maximize deltoid function.» Adjustments in the COR ultimately lead to changes in resting tension of the deltoid and remaining rotator cuff, which can affect implant stability and risk of stress fracture.» Soft-tissue balance and complication profiles can be affected by humeral component (version, neck shaft angle, and inlay vs. onlay) and glenoid component (sagittal placement, version, inclination, and lateralization) design and application.» A good understanding of the effects on soft-tissue balance and complication profile is critical for surgeons to best provide optimal patient outcomes.

Concomitant open distal clavicle excision is associated with greater improvement in range of motion without increased risk of acromial stress fracture after reverse total shoulder arthroplasty: a retrospective cohort study

BACKGROUND

The purpose of this study was to evaluate the effect of concomitant open distal clavicle excision (DCE) on postoperative clinical outcomes and incidence of acromial and scapular stress fractures (ASFs) in patients with symptomatic acromioclavicular joint osteoarthritis (ACJ OA) undergoing reverse total shoulder arthroplasty (RTSA).

METHODS

A single-surgeon retrospective cohort study was conducted including patients who underwent primary elective RTSA with or without DCE from 2015 to 2019 with a minimum 6-month follow-up period. Shoulder active range of motion (AROM) and visual analog scale (VAS) pain were recorded preoperatively and postoperatively. ASFs and other adverse events were identified using postoperative notes and/or radiographs. Characteristics and outcomes were compared between the RTSA and RTSA-DCE groups.

RESULTS

Forty-six RTSA patients (mean age, 67.9±8.7 years; 60.9% male; mean follow-up, 24.9±16.6 months) and 70 RTSA-DCE patients (mean age, 70.2±8.9 years; 20.0% male; mean follow-up, 22.7±12.9 months) were included. There were no significant intergroup differences in rates of ASF (RTSA, 0.0% vs. RTSA-DCE, 1.4%; P=1.00), stress reactions (RTSA, 8.7% vs. RTSA-DCE, 11.4%; P=0.76), reoperation, revision, or infection (all P>0.05), or in pre-to-postoperative reduction in VAS pain (P=0.17) at latest follow-up. However, the RTSA-DCE group had greater pre-to-postoperative improvement in flexion AROM (RTSA, 43.7°±38.5° vs. RTSA-DCE, 59.5°±33.4°; P=0.03) and internal rotation (IR) AROM (P=0.02) at latest follow-up.

CONCLUSIONS

Concomitant DCE in RTSA improves shoulder flexion and IR AROM, alleviates shoulder pain, and does not increase the risk of ASFs. Level of evidence: III.

Effect of using a small baseplate on the radiological and clinical outcomes of reverse total shoulder arthroplasty in Asian patients

Aims

The aim of this study was to compare the clinical and radiological outcomes of reverse shoulder arthroplasty (RSA) using small and standard baseplates in Asian patients, and to investigate the impact of a mismatch in the sizes of the glenoid and the baseplate on the outcomes.

Methods

This was retrospective analysis of 50 and 33 RSAs using a standard (33.8 mm, ST group) and a small (29.5 mm, SM group) baseplate of the Equinoxe reverse shoulder system, which were undertaken between January 2017 and March 2021. Radiological evaluations included the size of the glenoid, the β-angle, the inclination of the glenoid component, inferior overhang, scapular notching, the location of the central cage in the baseplate within the vault and the mismatch in size between the glenoid and baseplate. Clinical evaluations included the range of motion (ROM) and functional scores. In subgroup analysis, comparisons were performed between those in whom the vault of the glenoid was perforated (VP group) and those in whom it was not perforated (VNP group).

Results

Perforation of the vault of the glenoid (p = 0.018) and size mismatch in height (p < 0.001) and width (p = 0.013) were significantly more frequent in the ST group than in the SM group. There was no significant difference in the clinical scores and ROM in the two groups, two years postoperatively (all p > 0.05). In subgroup analysis, the VP group had significantly less inferior overhang (p = 0.009), more scapular notching (p = 0.018), and more size mismatch in height (p < 0.001) and width (p = 0.025) than the VNP group.

Conclusion

In Asian patients with a small glenoid, using a 29.5 mm small baseplate at the time of RSA was more effective in reducing size mismatch between the glenoid and the baseplate, decreasing the incidence of perforation of the glenoid vault, and achieving optimal positioning of the baseplate compared with the use of a 33.8 mm standard baseplate. However, longer follow-up is required to assess the impact of these findings on the clinical outcomes.

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.

Reverse Shoulder Arthroplasty Patients Younger Than 60 Years Old Exhibit Lower Clinically Significant Single Assessment Numeric Evaluation (SANE) Scores Compared to Older Patients

INTRODUCTION

The incidence of reverse shoulder arthroplasty (RTSA) in the United States has increased. Patients under 60 years old with failed rotator cuff repairs or degenerative joint disease with glenoid deformity may be candidates for RTSA and contribute to this increase. The single assessment numeric evaluation (SANE) score is a reliable post-operative scoring technique when compared with other post-operative measures. This study aimed to compare the effect of age on the likelihood of reaching clinically significant SANE scores following RTSA.

METHODS

A multicenter retrospective review was performed with a consecutive series of RTSA from December 2015 to September 2021. Patients were stratified into groups based on their age at the time of operation: (1) less than 60 years old, (2) 60-69 years old, (3) 70-79 years old, and (3) greater than 80 years old. The proportions of patients in all cohorts reaching and surpassing clinically significant thresholds at each visit were determined. Likelihood ratios were determined for each age cohort to compare the likelihood of reaching clinically significant SANE scores.

RESULTS

A total of 292 of 885 (33%) patients had completed survey data over two years and were included in the study. The 70-79-year-old group was 3.152 (p=.035) times more likely to achieve minimal clinically important difference (MCID) and 2.125 (p=.048) times more likely to achieve patient-acceptable symptomatic state (PASS) compared with patients <60 years old. The cohort who was 80+ years old was also 4.867 (p=.045) times more likely to achieve MCID compared to the <60-year-old cohort. The <60 cohort had the lowest proportion of all patient cohorts achieving MCID.

CONCLUSION

A lower proportion of patients younger than 60 years old undergoing RTSA achieved clinically significant post-operative SANE scores. The 70-79-year-old age group was more likely to reach MCID and PASS, and the patients who were 80+ years old were more likely to reach MCID compared to patients younger than 60 years old.

How common is nerve injury after reverse shoulder arthroplasty? A systematic review

BACKGROUND

Nerve injury following reverse shoulder arthroplasty (RSA) is a known risk factor with wide ranging incidences reported. This systematic review evaluates the overall incidence of nerve injury following primary and revision RSA and summarizes the characteristics of the nerve injuries reported in the current literature.

METHODS

A systematic review was performed using separate database searches (Pubmed, Embase, Web of Science, Cochrane) following the PRISMA guidelines. Search criteria included the title terms "reverse shoulder," "reverse total shoulder," "inverted shoulder," and "inverted total shoulder" with publication dates ranging from 01/01/2010 to 01/01/2022. Studies that reported neurological injuries and complications were included and evaluated for primary RSA, revision RSA, number of nerve injuries, and which nerves were affected.

RESULTS

After exclusion, our systematic review consisted of 188 articles. A total of 40,146 patients were included, with 65% female. The weighted mean age was 70.3 years. The weighted mean follow-up was 35.4 months. The rate of nerve injury after RSA was 1.3% (510 of 40,146 RSAs). The rate of injury was greater in revision RSA compared to primary RSA (2.4% vs. 1.3%). Nerve injury was most common in RSAs done for a primary diagnosis of acute proximal humerus fracture (4.0%), followed by cuff tear arthropathy (3.0%), DJD (2.6%), and inflammatory arthritis (1.7%). Massive rotator cuff tears and post-traumatic arthritis cases had the lowest nerve injury rates (1.0% and 1.4%, respectively). The axillary nerve was the most commonly reported nerve that was injured in both primary and revision RSA (0.6%), followed by the ulnar nerve (0.26%) and median nerve (0.23%). Brachial plexus injury was reported in 0.19% of overall RSA cases.

CONCLUSION

Based on current English literature, nerve injuries occur at a rate of 1.3% after primary RSA compared with 2.4% after revision RSA. The most common nerve injury was to the axillary nerve (0.64%), with the most common operative diagnosis associated with nerve injury after RSA being acute proximal humerus fracture (4.0%). Surgeons should carefully counsel patients prior to surgery regarding the risk of nerve injury.

Minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) of upper extremity PROMIS scores in idiopathic adhesive capsulitis

INTRODUCTION

The purpose of this study is to calculate the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state (PASS) of Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity Computer Adaptive Testing v2.0 (UE), Pain Interference (P-Interference), and Pain Intensity (P-Intensity) in patients treated nonoperatively for idiopathic adhesive capsulitis (IAC).

METHODS

The anchor-based MCID, SCB, and PASS were calculated as the change in PROMIS scores representing the optimal cutoff for a ROC curve with an area under the curve (AUC) analysis. The distribution-based MCID was calculated as a range between the average standard error of measurement multiplied by two different constants: 1 and 2.77. Effect sizes and standardized response means (SRM) were calculated to assess the responsiveness of each PROMIS instrument while regression analyses were performed to identify factors associated with achieving these thresholds.

RESULTS

This study enrolled 115 patients. The anchor-based MCID for PROMIS UE, P-Interference, and P-Intensity was 5.11, 4.16, and 8.16, respectively. The respective SCB was 8.44, 6.65, and 10.05. The respective PASS was 8.47, 7.01, and 10.41. The odds of achieving MCID values in adhesive capsulitis were negatively affected by gender (male), higher forward elevation at the time of presentation, higher pain scores (P-Interference), need for ≥ 2 corticosteroid injections, and a concomitant diagnosis of diabetes.

CONCLUSION

The MCID, SCB, and PASS parameters for PROMIS scores can be utilized to determine the clinical meaningfulness of patient-reported improvements in these instruments during the nonoperative treatment and as a research tool to compare the efficacy of new treatments for adhesive capsulitis.

LEVEL OF EVIDENCE

Level III, basic science study, validation of outcome instruments. Key points • This is the first study to calculate the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for the Patient-Reported Outcome Measurement Information System (PROMIS) Upper Extremity and Pain instruments in patients with idiopathic adhesive capsulitis (IAC) of the shoulder.• This study determined the impact of symptom severity, demographics, and comorbidities on achieving the MCID, SCB, and PASS for PROMIS instruments in IAC patients treated nonoperatively.

Minimal clinically important difference (MCID) and substantial clinical benefit (SCB) of upper extremity PROMIS scores following arthroscopic rotator cuff repairs

PURPOSE

To calculate and determine what factors are associated with achieving the Minimal Clinically Important Difference (MCID) and the Substantial Clinical Benefit (SCB) of Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity Computer Adaptive Testing v2.0 (UE), Pain Interference (P-Interference), and Pain Intensity (P-Intensity) in patients undergoing arthroscopic rotator cuff repair (aRCR).

METHODS

The change in PROMIS scores representing the optimal cutoff for a ROC curve with an area under the curve analysis was used to calculate the anchor-based MCID and SCB. To assess the responsiveness of each PROM, effect sizes and standardized response means (SRM) were calculated. To identify factors associated with attaining the MCID and SCB, univariate and multivariate logistic regression analyses were performed.

RESULTS

A total of 323 patients with an average age of 59.9 ± 9.5 were enrolled in this study, of which, 187/323 [57.9%] were male and 136/323 [42.1%] were female. The anchor-based MCID for PROMIS UE, P-Interference, and P-Intensity was: 9.0, 7.5, and 11.2, respectively. The respective SCB was 10.9, 9.3, and 12.7. Effect size and SRM were: PROMIS UE (1.4, 1.3), P-Interference (1.8, 1.5), and P-Intensity (2.3, 2.0). Lower preoperative P-Intensity scores (p = 0.02), dominant arm involvement (p = 0.03), and concomitant biceps tenodesis (p = 0.03) were associated with patients achieving the SCB for PROMIS UE.

CONCLUSION

A large responsiveness for each of the PROMIS instruments due to the majority of patients reporting great improvement after aRCR and a small standard deviation across all outcome measures was shown in our study. Lower preoperative P-Intensity scores and concomitant biceps tenodesis were associated with higher odds of achieving the SCB for PROMIS UE. The knowledge of MCID and SCB values for PROMIS instruments will allow the surgeon to determine whether the improvements in the PROMIS scores after aRCR are clinically meaningful.

LEVEL OF EVIDENCE

Level III.

Outcomes and complications of primary reverse shoulder arthroplasty with minimum of 2 years' follow-up: a systematic review and meta-analysis

BACKGROUND

Primary reverse shoulder arthroplasty (rTSA) is an effective treatment option for reducing pain and improving function for patients with rotator cuff tear arthropathy, irreparable rotator cuff tears, glenoid deformity, and other challenging clinical scenarios, including fracture sequelae and revision shoulder arthroplasty. There has been a wide range of reported outcomes and postoperative complication rates reported in the literature. The purpose of this systematic review and meta-analysis is to provide an updated review of the clinical outcomes and complication rates following primary rTSA.

METHODS

A systematic review and meta-analysis was performed to evaluate outcomes and complications following primary rTSA according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Demographics, range of motion, patient-reported outcome measures (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES] and Constant scores), number of complications, and revisions were extracted, recorded, and analyzed from the included articles.

RESULTS

Of the 1415 studies screened, 52 studies met the inclusion criteria comprising a total of 5824 shoulders. The mean age at the time of surgery was 72 years (range: 34-93), and the mean follow-up was 3.9 years (range: 2-16). Patients demonstrated a mean improvement of 56° in active flexion, 50° in active abduction, and 14° in active external rotation. Regarding functional outcome scores, rTSA patients demonstrated a mean clinically significant improvement of 37 in Constant score (minimal clinically important difference [MCID] = 5.7) and ASES score (42.0; MCID = 13.6). The overall complication rate for rTSA was 9.4% and revision rate of 2.6%. Complications were further subdivided into major medical complications (0.07%), shoulder- or surgical-related complications (5.3%), and infections (1.2%). The most frequently reported shoulder- or surgical-related complications were scapular notching (14.4%), periprosthetic fracture (0.8%), glenoid loosening (0.7%), and prosthetic dislocation (0.7%).

DISCUSSION

Primary rTSA is a safe and reliable procedure with low complication, revision, infection, and scapular notching rates. Additionally, patients demonstrated clinically significant improvements in both range of motion and clinical outcome scores.

[Cuff Arthropathy - Inverse Total Shoulder Arthroplasty (iSTEP) - Biomechanical Principles, Complications and Outcomes]

The inverse total shoulder prosthesis is a standard treatment for cuff arthropathy. The number of implanted inverse total shoulder prostheses in Germany is significantly higher than that of the anatomical total shoulder prosthesis. Kaplan-Meier analyses show a 10-year result of inverse total shoulder prostheses after cuff arthropathy of 90%. The extent of the scapular notching correlates with the functional clinical outcome. The humeral anchoring principles of inverse total shoulder prosthesis differ considerably (from purely epiphyseal to diaphyseal). Inverse total shoulder prostheses show significant differences in humeral and glenoid offset as well as in shaft-neck angles. The large number of systems available differ considerably concerning anatomical and biomechanical parameters - the surgeons must be trained accordingly. Still, most shoulder replacements are implanted by surgeons who rarely perform this procedure.

Inverted-Bearing Reverse Shoulder Arthroplasty: Consequences on Scapular Notching and Clinical Results at Mid-Term Follow-Up

Background: Scapular notching following reverse shoulder arthroplasty (RSA) is caused by both biological and mechanical mechanisms. Some authors postulated that osteolysis that extends over the inferior screw is caused mainly by biological notching. Inverted-bearing RSA (IB-RSA) is characterized by a polyethylene glenosphere and a metallic humeral liner, decreasing the poly debris formation and potentially reducing high grades of notching. This study aims to report the results of IB-RSA on a consecutive series of patients at mid-term follow-up, focusing on the incidence of Sirveaux grade 3 and 4 scapular notching. Methods: A retrospective study on 78 consecutive patients who underwent primary IB-RSA between 2015−2017 was performed. At a 4 years minimum follow-up, 49 patients were evaluated clinically with Constant score (CS), Subjective shoulder value (SSV), American Shoulder and Elbow score (ASES), pain and range of motion, and with an X-ray assessing baseplate position (high, low), implant loosening, and scapular notching. Results: At a mean follow-up of 5.0 ± 0.9, all the clinical parameters improved (p < 0.05). One patient was revised for an infection and was excluded from the evaluation, two patients had an acromial fracture, and one had an axillary neuropraxia. Scapular notching was present in 13 (27%) patients (six grade 1, seven grade 2) and no cases of grade 3 and 4 were observed. Scapular nothing was significantly associated with high glenoid position (p < 0.001) and with lower CS (70 ± 15 vs. 58 ± 20; p = 0.046), SSV (81 ± 14 vs. 68 ± 20; p = 0.027), ASES (86 ± 14 vs. 70 ± 22; p = 0.031), and anterior elevation (148 ± 23 vs. 115 ± 37; p = 0.006). A 44 mm- compared to 40 mm-glenosphere was associate with better CS (63 ± 17 vs. 78 ± 11; p = 0.006), external (23 ± 17 vs. 36 ± 17; p = 0.036), and internal rotation (4.8 ± 2.7 vs. 7.8 ± 2.2; p = 0.011). Conclusions: IB-RSA is a safe and effective procedure for mid-term follow-up. Inverting biomaterials leads to a distinct kind of notching with mainly mechanical features. Scapular notching is associated with a high baseplate position and has a negative influence on range of motion and clinical outcome.

Association between sagittal spinal alignment and postoperative shoulder range of motion following reverse total shoulder arthroplasty

BACKGROUND

The range of internal rotation sometimes deteriorates after reverse total shoulder arthroplasty; however, the underlying mechanisms remain unclear. This study aimed to investigate the association between sagittal spinal alignment and internal rotation deterioration after reverse total shoulder arthroplasty.

METHODS

We retrospectively reviewed 52 patients who underwent reverse total shoulder arthroplasty by a single surgeon between October 2014 and December 2018. The sagittal spine was radiographed, and the sagittal spinal alignment was evaluated based on 10 parameters (e.g. C7-HA: the distance between the plumb line from the center of the seventh cervical vertebral body and the center of the hip axis). We divided the patients into two groups, group A (internal rotation deterioration; 23 patients) and B (without internal rotation deterioration; 29 patients). Logistic regression analysis was performed to analyze the association between sagittal spinal alignment and internal rotation deterioration after reverse total shoulder arthroplasty, and a receiver operating characteristic curve was used to analyse the cutoff value of independent variables that was correlated with IR deterioration.

RESULTS

Logistic regression analysis demonstrated the correlation between C7-HA and internal rotation deterioration (odds ratio, 1.95; 95% confidence interval, 1.33-2.84; P < 0.001). The receiver operating characteristic curve suggested that when C7-HA was at least 2.44 cm, it was strongly correlated with deterioration of internal rotation (sensitivity, 91.3%; specificity, 93.1%; P < 0.001; area under the curve, 0.938). Group A was significantly inferior to group B in not only internal rotation but also flexion and abduction.

CONCLUSIONS

This study suggested that a remarkably positive value in C7-HA was a factor that was correlated with deterioration of internal rotation. In addition, the deformation of sagittal spinal alignment would impact on the range of motion after reverse total shoulder arthroplasty.

Factors associated with improvement or loss of internal rotation after reverse shoulder arthroplasty

BACKGROUND

Internal rotation (IR) with reverse total shoulder arthroplasty (rTSA) can be unpredictable. Identifying the factors associated with loss of or improved IR could aid preoperative patient counseling. This study quantifies the change in IR experienced by rTSA patients with nonfracture indications and identifies the patient, implant, and operative factors associated with IR loss or gain at 2-year minimum follow-up.

METHODS

A total of 1978 primary rTSA patients were analyzed from an international database of a single rTSA prosthesis to quantify IR at 2 years' minimum follow-up. rTSA patients were divided into 2 cohorts based on their preoperative IR score, with group 1 patients having less active IR as defined by a preoperative IR score ≤3 and group 2 patients having greater active IR as defined by a preoperative IR score ≥4 (ie, L5 or higher). For both group 1 and 2 patients, univariate and multivariate analyses were performed to quantify the risk factors associated with IR loss after rTSA.

RESULTS

Overall, 58.9% of rTSA patients experienced IR improvement and 17.0% lost IR after rTSA. The occurrence of IR loss or gain was dependent on preoperative IR score, as 73.2% of group 1 patients improved IR and only 40.1% of group 2 patients improved IR, whereas 31.0% of group 2 patients lost IR and only 6.3% of group 1 patients lost IR after rTSA. Numerous risk factors for IR loss were identified. For group 1 patients, male sex (P = .004, odds ratio [OR] = 2.056), tobacco usage (P = .004, OR = 0.348), larger humeral stem diameter (P = .008, OR = 0.852), and not having subscapularis repaired (P = .002, OR = 2.654) were significant risk factors for IR loss. For group 2 patients, male sex (P = .005, OR = 1.656), higher body mass index (P = .002, OR = 0.946), a diagnosis other than osteoarthritis (P < .001, OR = 2.189), nonaugmented baseplate usage (P < .001, OR = 2.116), and not having subscapularis repaired (P < .001, OR = 3.052) were significant risk factors for IR loss.

CONCLUSION

The majority of patients improve IR after rTSA in the nonfracture setting. rTSA patients with substantial IR prior to surgery had a greater probability for losing IR compared to patients with poor preoperative IR. Numerous risk factors for IR loss were identified; these risk factors are useful for counseling patients considering rTSA, as some patients are more likely to lose IR than others.

Effect of glenosphere size on reverse shoulder arthroplasty revision rate: an analysis from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR)

BACKGROUND

Modularity is an integral element of reverse total shoulder arthroplasty (RTSA). Glenosphere diameter is a key component, but its effect on revision rate is unknown. The aim of this study was to investigate the relationship between glenosphere size and revision rates in RTSA procedures.

METHODS

Data from a large national arthroplasty registry were analyzed for the period April 2004 to 31 December 2019. The study population included all primary RTSA procedures using glenosphere sizes <38 mm, 38-40 mm, and >40 mm. A subanalysis of glenosphere sizes for each of the 3 most commonly implanted prostheses and further analyses by patient age and gender were also performed. The rate of revision was determined by Kaplan-Meier estimates, with comparisons by Cox proportional hazard models.

RESULTS

There were 28,817 primary RTSA procedures. Glenosphere sizes <38 mm had a higher revision rate compared to 38-40-mm glenospheres (hazard ratio [HR] 1.28, 95% confidence interval [CI] 1.11, 1.48, P < .001) and >40-mm sizes (HR 1.35, 95% CI 1.15, 1.59, P < .001). Males with <38-mm and 38-40-mm glenospheres had significantly higher revision rates compared to >40-mm glenospheres (HR 1.49, 95% CI 1.21, 1.83, P < .001; and HR 1.28, 95% CI 1.03, 1.58, P = .025, respectively). Females with <38-mm and >40-mm glenospheres had higher revision rates compared to females with 38-40-mm glenospheres (HR 1.38, 95% CI 1.14, 1.68, P < .001; and HR 1.41, 95% CI 1.06, 1.88, P = .019, respectively). For patients aged 65-74 years, glenospheres >40 mm had a significantly lower revision rate than both the <38-mm glenospheres (entire period: HR 0.59, 95% CI 0.45, 0.76, P < .001) and 38-40-mm glenospheres (entire period: HR 0.72, 95% CI 0.54, 0.94, P = .017). For patients aged ≥75 years (n = 14,622), <38-mm glenospheres had a significantly higher rate of revision compared with 38-40-mm glenospheres after 3 months (HR  1.43, 95% CI 1.09, 1.86, P = .009). Analysis comparing glenosphere sizes within each of the 3 most commonly implanted prostheses found that the Delta Xtend with 38-40-mm glenospheres had higher revision rates compared with >40-mm glenospheres (HR 1.49, 95% CI 1.14, 1.92, P = .003). The SMR L1 (Lima) 38-40-mm glenospheres had a lower rate of revision compared with the <38-mm (HR 0.50, 95% CI 0.37, 0.67, P < .001) and >40-mm glenospheres (HR 0.60, 95% CI 0.43, 0.85, P = .004).

CONCLUSIONS

Glenospheres <38 mm can be expected to increase revision rates in primary RTSAs. The optimum size of glenospheres is gender, age, and prosthesis specific, with revision rates lower for females with 38-40-mm glenospheres and lower for males with >40-mm glenospheres.

Factors Associated with Internal Rotation After Reverse Shoulder Arthroplasty: A Narrative Review

Reverse shoulder arthroplasty (RSA) leads to improvement in pain and function with a durable outcome in most cases. While improvement in forward flexion and to a lesser degree external rotation is predictably seen after RSA, restoration of internal rotation (IR) is much less predictable. The purpose of this review was to provide a narrative of the modifiable factors, including prosthetic design and surgical factors, that may impact postoperative IR after RSA. Overall, the available data suggest that postoperative IR is improved with a lower humeral neck shaft angle and lateralization of the glenoid. Decreasing humeral retroversion to 20° or less improves IR at the cost of decreasing active external rotation. Increasing glenosphere diameter improves IR but often within the setting of additional variables. The association between subscapularis repair is less clear but overall suggests that IR is improved postoperatively when it is repaired.

Postoperative stiffness after reverse total shoulder arthroplasty

PURPOSE

The purpose of this study was to evaluate the rate and risk factors for stiffness after reverse shoulder arthroplasty and the ramifications on the patient-reported outcomes.

METHOD

A consecutive series of patients who underwent reverse shoulder arthroplasty were prospectively followed for one year. Passive range of motion was measured preoperatively and at regular intervals postoperatively. Patients with passive forward elevation of less than 100° or passive external rotation of less than 30° were defined as stiff. Radiographic parameters and postoperative patient-reported outcome scores were collected.

RESULTS

Seventy-six patients were available for review. The prevalence of postoperative stiffness following reverse shoulder arthroplasty was 47% at three months, 31% at six months, and 25% at one year. Preoperative shoulder stiffness was associated with three-month postoperative stiffness only. In patients with one-year stiffness, smaller (p = 0.03) and less lateralized glenospheres (p = 0.024) were more common. Stiffness was not associated with one-year patient-reported outcome scores.

CONCLUSION

Stiffness is common after reverse shoulder arthroplasty and often improves at one-year after surgery. Implant design and selection may be important determinants of passive range of motion. While stiffness does not appear to influence patient-reported outcome scores, one of four patients will potentially have stiffness one year following reverse shoulder arthroplasty.Level of evidence: Level III; retrospective study.

Implant characteristics affect in vivo shoulder kinematics during multiplanar functional motions after reverse shoulder arthroplasty

The purpose of this study was to determine how implant characteristics affect in vivo shoulder kinematics after reverse shoulder arthroplasty (RSA). Kinematics of the affected upper limb were measured in 32 participants during five motions (scapular plane abduction, hand-to-head, hand-to-back, internal/external rotation at 90° abduction, and circumduction) using optical motion capture. Shoulder abduction, plane of elevation, and internal/external rotation range of motion (ROM), peak angles, and continuous kinematics waveforms were calculated for each motion. Multiple regression was used to identify associations between kinematics and implant characteristics of lateralization, humeral retroversion, glenosphere size, glenosphere tilt, glenoid eccentricity, and implant neck-shaft angle (135° or 145°). Less humeral retroversion was associated with greater shoulder rotation ROM (p = 0.036) and greater plane of elevation ROM (p = 0.024) during circumduction, while less eccentricity was associated with more posterior plane of elevation during hand-to-back (p = 0.021). The 145° implant was associated with greater internal/external shoulder rotation ROM (p < 0.001), greater internal shoulder rotation (p = 0.002), and greater plane of elevation ROM (p = 001) during the hand-to-back. The 145° implant was also associated with more internal/external rotation ROM (p = 0.043) during shoulder rotation and more abduction ROM during circumduction (p = 0.043). During the hand-to-back motion, individuals having 135° neck-shaft angle implants were more abducted from 21 to 51% of the motion and were less internally rotated from 70 to 100% of the motion, while more lateralization was associated with less internal rotation from 90 to 100% of the motion. Retroversion and implant neck-shaft angle are the primary implant characteristics associated with in vivo shoulder kinematics during complex motions after RSA.

The Evolution of Reverse Total Shoulder Arthroplasty-From the First Steps to Novel Implant Designs and Surgical Techniques

PURPOSE OF REVIEW

The purpose of this review is to summarize recent literature regarding the latest design modifications and biomechanical evolutions of reverse total shoulder arthroplasty and their impact on postoperative outcomes.

RECENT FINDINGS

Over the past decade, worldwide implantation rates of reverse total shoulder arthroplasty have drastically increased for various shoulder pathologies. While Paul Grammont's design principles first published in 1985 for reverse total shoulder arthroplasty remained unchanged, several adjustments were made to address postoperative clinical and biomechanical challenges such as implant glenoid loosening, scapular notching, or limited range of motion in order to maximize functional outcomes and increase the longevity of reverse total shoulder arthroplasty. However, the adequate and stable fixation of prosthetic components can be challenging, especially in massive osteoarthritis with concomitant bone loss. To overcome such issues, surgical navigation and patient-specific instruments may be a viable tool to improve accurate prosthetic component positioning. Nevertheless, larger clinical series on the accuracy and possible complications of this novel technique are still missing.

Patient Posture Affects Simulated ROM in Reverse Total Shoulder Arthroplasty: A Modeling Study Using Preoperative Planning Software

BACKGROUND

Component selection and placement in reverse total shoulder arthroplasty (RTSA) is still being debated. Recently, scapulothoracic orientation and posture have emerged as relevant factors when planning an RTSA. However, the degree to which those parameters may influence ROM and whether modifiable elements of implant configuration may be helpful in improving ROM among patients with different postures have not been thoroughly studied, and modeling them may be instructive.

QUESTIONS/PURPOSES

Using a dedicated expansion of a conventional preoperative planning software, we asked: (1) How is patient posture likely to influence simulated ROM after virtual RTSA implantation? (2) Do changes in implant configuration, such as humeral component inclination and retrotorsion, or glenoid component size and centricity improve the simulated ROM after virtual RTSA implantation in patients with different posture types?

METHODS

In a computer laboratory study, available whole-torso CT scans of 30 patients (20 males and 10 females with a mean age of 65 ± 17 years) were analyzed to determine the posture type (Type A, upright posture, retracted scapulae; Type B, intermediate; Type C, kyphotic posture with protracted scapulae) based on the measured scapula internal rotation as previously described. The measurement of scapular internal rotation, which defines these posture types, was found to have a high intraclass correlation coefficient (0.87) in a previous study, suggesting reliability of the employed classification. Three shoulder surgeons each independently virtually implanted a short, curved, metaphyseal impaction stem RTSA in each patient using three-dimensional (3D) preoperative surgical planning software. Modifications based on the original component positioning were automatically generated, including different humeral component retrotorsion (0°, 20°, and 40° of anatomic and scapular internal rotation) and neck-shaft angle (135°, 145°, and 155°) as well as glenoid component configuration (36-mm concentric, 36-mm eccentric, and 42-mm concentric), resulting in 3720 different RTSA configurations. For each configuration, the maximum potential ROM in different planes was determined by the software, and the effect of different posture types was analyzed by comparing subgroups.

RESULTS

Irrespective of the RTSA implant configuration, the posture types had a strong effect on the calculated ROM in all planes of motion, except for flexion. In particular, simulated ROM in patients with Type C compared with Type A posture demonstrated inferior adduction (median 5° [interquartile range -7° to 20°] versus 15° [IQR 7° to 22°]; p < 0.01), abduction (63° [IQR 48° to 78°] versus 72° [IQR 63° to 82°]; p < 0.01), extension (4° [IQR -8° to 12°] versus 19° [IQR 8° to 27°]; p < 0.01), and external rotation (7° [IQR -5° to 22°] versus 28° [IQR 13° to 39°]; p < 0.01). Lower retrotorsion and a higher neck-shaft angle of the humeral component as well as a small concentric glenosphere resulted in worse overall ROM in patients with Type C posture, with severe restriction of motion in adduction, extension, and external rotation to below 0°.

CONCLUSION

Different posture types affect the ROM after simulated RTSA implantation, regardless of implant configuration. An individualized choice of component configuration based on scapulothoracic orientation seems to attenuate the negative effects of posture Type B and C. Future studies on ROM after RTSA should consider patient posture and scapulothoracic orientation.

CLINICAL RELEVANCE

In patients with Type C posture, higher retrotorsion, a lower neck-shaft angle, and a larger or inferior eccentric glenosphere seem to be advantageous.

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.

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.

Problems, complications, and reinterventions in 4893 onlay humeral lateralized reverse shoulder arthroplasties, a systematic review: part II-problems and reinterventions

BACKGROUND

Several modifications to the original Grammont reverse shoulder arthroplasty (RSA) design have been proposed to prevent distinctive issues, such as both glenoid and humeral lateralization. The aim of this systematic review was to determine rates of problems, complications, reoperations, and revisions after onlay lateralized humeral stem RSA, hypothesizing that these are design related.

METHODS

This systematic review was performed in accordance with the PRISMA statement guidelines. A literature search was conducted (1 January 2000 to 14 April 2020) using PubMed, Cochrane Reviews, Scopus, and Google Scholar, employing several combinations of keywords: "reverse shoulder arthroplasty," "reverse shoulder prosthesis," "inverse shoulder arthroplasty," "inverse shoulder prosthesis," "problems," "complications," "results," "outcomes," "reoperation," and "revision."

RESULTS

Thirty-one studies with 4893 RSA met inclusion criteria. The 892 postoperative problems and 296 postoperative complications represented overall problem and complication rates of 22.7% and 7.5%, respectively. Forty-one reoperations and 63 revisions resulted, with overall reoperation and revision rates of 1.7% and 2.6%, respectively.

CONCLUSIONS

Problem, complication, and reintervention rates proved acceptable when implanting a high humeral lateralization stem RSA. The most frequent problem was scapular notching (12.6%), and the most common postoperative complication was scapular stress fracture (1.8%). An overall humeral complication rate of 1.9% was identified, whereas no humeral fractures or stem loosening were reported with short stems. Infections (1.3%) were the most common reason for component revision, followed by instability (0.8%).

LEVEL OF EVIDENCE

Systematic review IV.

Problems, complications, and reinterventions in 4893 onlay humeral lateralized reverse shoulder arthroplasties: a systematic review (part I-complications)

Background

Several modifications to the original Grammont reverse shoulder arthroplasty (RSA) design have been proposed to prevent distinctive issues, such as both glenoid and humeral lateralization. The aim of this systematic review was to determine rates of problems, complications, reoperations, and revisions after onlay lateralized humeral stem RSA, hypothesizing that these are design related.

Methods

This systematic review was performed in accordance with the PRISMA statement guidelines. A literature search was conducted (01.01.2000–14.04.2020) using PubMed, Cochrane Reviews, Scopus, and Google Scholar employing several combinations of keywords: “reverse shoulder arthroplasty,” “reverse shoulder prosthesis,” “inverse shoulder arthroplasty,” “inverse shoulder prosthesis,” “problems,” “complications,” “results,” “outcomes,” “reoperation,” “revision.”

Results

Thirty-one studies with 4893 RSA met inclusion criteria. The 892 postoperative problems and 296 postoperative complications represented overall problem and complication rates of 22.7% and 7.5%, respectively. Forty-one reoperations and 63 revisions resulted, with an overall reoperation rate of 1.7% and overall revision rate of 2.6%.

Conclusions

Problem, complication, and reintervention rates proved acceptable when implanting a high humeral lateralization stem in RSA. The most frequent problem was scapular notching (12.6%), and the most common postoperative complication was scapular stress fracture (1.8%). An overall humeral complication rate of 1.9% was identified, whereas short stems reported no humeral fractures or stem loosening. Infections (1.3%) proved to be the most common reason for component revision, and instability had a complication rate of 0.8%.

Level of evidence

Systematic review IV

Three-dimensional kinematics of reverse shoulder arthroplasty: a comparison between shoulders with good or poor elevation

Background

Various factors may be related to outcomes of reverse shoulder arthroplasty (RSA) including patient and surgical factors. Differences in shoulder kinematics might be associated with poor function after RSA; however, kinematic differences between shoulders with good or poor elevation have not been elucidated. The purpose of this study was to compare RSA kinematics between shoulders with good or poor elevation.

Methods

The study included 28 shoulders with a minimum 6-month follow-up after RSA using Grammont-type prostheses. Subjects comprised 17 men and 11 women with the mean age of 75 years (range, 63-91). Subjects underwent fluoroscopy during active scapular plane abduction. Computed tomography of their shoulders was performed to create 3-dimensional scapular implant models. Using model-image registration techniques, poses of 3-dimensional implant models were iteratively adjusted to match their silhouettes with the silhouettes in the fluoroscopic images, and 3-dimensional kinematics of implants were computed. Kinematics and glenosphere orientation were compared between shoulders with good (>90 degree) or poor (<90 degree) scapular plane abduction.

Results

Nineteen and 9 shoulders were assigned to the good- and poor-elevation groups, respectively. There were no significant differences between the groups in age, sex, height, weight, preoperative range of motion, or Constant score, but body mass index in the poor elevation shoulders was significantly larger than that in the good elevation shoulders. There were no significant differences in glenosphere (upward/downward rotation, anterior/posterior tilt, internal/external rotation) or glenohumeral (internal/external rotation, abduction/adduction) kinematics between the good and poor elevation shoulders. Scapulohumeral rhythm was significantly higher in the good elevation shoulders than the poor elevation shoulders (P = .04). Glenosphere superior tilt was 2.3° ± 4.2° in the good-elevation group and 8.1° ± 8.9° in the poor-elevation group, and the difference was statistically significant (P = .03).

Discussion

Shoulders with good elevation after RSA demonstrated better scapulohumeral rhythm than those with poor elevation, though there were no significant differences in glenosphere and glenohumeral kinematics. It may be important for better elevation to achieve good glenohumeral motion in shoulders with RSA. Glenosphere orientations may affect postoperative shoulder function.

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

Larger polyethylene glenospheres in reverse shoulder arthroplasty: are they safe?

Background

Reverse shoulder arthroplasty is gaining popularity owing to its proven longevity and good outcome scores. Scapular notching remains a concern. This study aimed to assess the safety of larger polyethylene glenospheres with increased eccentricity in comparison with the more conventional metal bearings. The secondary effects on scapular notching, clinical outcomes, range of movement, and complications were also analyzed.

Methods

We conducted a 10-year retrospective review of 145 SMR reverse shoulder arthroplasties (LimaCorporate, Udine, Italy) in 132 patients with radiographs at a minimum of 2 years postoperatively. The primary outcome measure was the survivorship of the larger polyethylene glenospheres. Secondary outcomes were the presence and size of notching, subjective satisfaction score, American Shoulder and Elbow Surgeons score, Oxford Shoulder Score, range of motion, and shoulder-related complications.

Results

No failures of the polyethylene glenospheres were noted in the 10-year period. At a minimum of 2 years’ follow-up, notching was noted in 16 (25%) of the metal glenospheres vs. 9 (11.1%) of the polyethylene glenospheres (P = .028). The mean Oxford Shoulder Score was lower for the metal glenospheres (P = .005). Range of motion, complications, and overall satisfaction were similar in both groups.

Conclusion

The inverted bearing configuration demonstrated no failures at a minimum of 2 years’ follow-up. A larger study is required to determine whether the decreased incidence and size of early notching are related to the bearing size or material.

Acromial fracture after reverse total shoulder arthroplasty: a systematic review

BACKGROUND

The reverse total shoulder arthroplasty has become the most common method of arthroplasty of the shoulder. The complication of acromial or scapular stress fracture deserves consideration to describe incidence and determine whether prosthetic design or patient factors act as risk factors.

METHODS

A systematic review of the literature was performed including the EMBASE, Medline and the Cochrane Library in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

The search returned 565 articles. After exclusion, 25 papers remained. In total, 208 fractures were reported in the literature, with an overall incidence of 5% and stress fractures were more common than post-traumatic ones; 24 fractures underwent osteosynthesis and there were nine revision arthroplasty surgeries. Outcomes worsened after fracture - whether treated with surgery or not. In patients with scapular base fractures, there was an improvement in functional outcome scores after surgery. Heterogeneous reporting of the risk factors prior to fractures, treatment methods and outcomes made recommendations weak.

DISCUSSION

Acromial stress fracture after reverse total shoulder arthroplasty occurs relatively commonly but is poorly reported in the literature. It is unclear whether immobilisation, fixation or revision arthroplasty is the best treatment, although fixation may offer a better outcome. In future, reports should aim for greater consistency to allow a better understanding of this condition.

Acromial and Scapular Fractures After Reverse Total Shoulder Arthroplasty with a Medialized Glenoid and Lateralized Humeral Implant: An Analysis of Outcomes and Risk Factors

This article was updated on TK because of a previous error, which was discovered after the preliminary version of the article was posted online. In Table VII, the fracture rate in the study by Walch et al. that had read "4.6% (21 of 457)" now reads "0.9% (4 of 457)."

BACKGROUND

Acromial and scapular fractures after reverse total shoulder arthroplasty (rTSA) are rare and challenging complications, and little information is available in the literature to identify patients who are at risk. This study analyzes risk factors for, and compares the outcomes of patients with and without, acromial and scapular fractures after rTSA with a medialized glenoid/lateralized humeral implant.

METHODS

Four thousand one hundred and twenty-five shoulders in 3,995 patients were treated with primary rTSA with 1 design of reverse shoulder prosthesis by 23 orthopaedic surgeons. Sixty-one of the 4,125 shoulders had radiographically identified acromial and scapular fractures. Demographic characteristics, comorbidities, implant-related data, and clinical outcomes were compared between patients with and without fractures to identify risk factors. A multivariate logistic regression, 2-tailed unpaired t test, and chi-square test or Fisher exact test identified significant differences (p < 0.05).

RESULTS

After a minimum duration of follow-up of 2 years, the rate of acromial and scapular fractures was 1.77%, with the fractures occurring at a mean (and standard deviation) of 17.7 ± 21.1 months after surgery. Ten patients had a Levy Type-1 fracture, 32 had a Type-2 fracture, 18 had a Type-3 fracture, and 1 fracture could not be classified. Patients with acromial and scapular fractures were more likely to be female (84.0% versus 64.5% [p = 0.004]; odds ratio [OR] = 2.75 [95% confidence interval (CI) = 1.45 to 5.78]), to have rheumatoid arthritis (9.8% versus 3.3% [p = 0.010]; OR = 3.14 [95% CI = 1.18 to 6.95]), to have rotator cuff tear arthropathy (54.1% versus 37.8% [p = 0.005]; OR = 2.07 [95% CI = 1.24 to 3.47]), and to have more baseplate screws (4.1 versus 3.8 screws [p = 0.017]; OR = 1.53 [95% CI = 1.08 to 2.17]) than those without fractures. No other implant-related differences were observed in the multivariate analysis. Patients with fractures had significantly worse outcomes than patients without fractures, and the difference in mean improvement between these 2 cohorts exceeded the minimum clinically important difference for the majority of measures.

CONCLUSIONS

Acromial and scapular fractures after rTSA are uncommon, and patients with these fractures have significantly worse clinical outcomes. Risk factors, including female sex, rheumatoid arthritis, cuff tear arthropathy, and usage of more baseplate screws were identified on multivariate logistic regression analysis. Consideration of these findings and patient-specific risk factors may help the orthopaedic surgeon (1) to better inform patients about this rare complication preoperatively and (2) to be more vigilant for this complication when evaluating patients postoperatively.

LEVEL OF EVIDENCE

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

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

Background

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

Methods

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

Results

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

Conclusions

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

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

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this 2-part study was to systematically review each of the most common complications of RSA, limiting each search to publications in 2010 or later. In this part (part I), we examined (1) scapular notching (SN), (2) periprosthetic infection (PJI), (3) mechanical failure (glenoid or humeral component), and (4) neurologic injury (NI).

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Overall, 113 studies on SN, 62 on PJI, 34 on mechanical failure, and 48 on NI were included in our reviews. Univariate analysis was performed with the χ² or Fisher exact test.

Results

The Grammont design had a higher SN rate vs. all other designs combined (42.5% vs. 12.3%, P < .001). The onlay humeral design had a lower rate than the lateralized glenoid design (10.5% vs. 14.8%, P < .001). The PJI rate was 2.4% for primary RSA and 2.6% for revision RSA. The incidence of glenoid and humeral component loosening was 2.3% and 1.4%, respectively. The Grammont design had an increased NI rate vs. all other designs combined (0.9% vs. 0.1%, P = .04).

Conclusions

Focused systematic reviews of the recent literature with a large volume of RSAs demonstrate that with the use of non-Grammont modern prosthesis designs, complications including SN, PJI, glenoid component loosening, and NI are significantly reduced compared with previous studies. As the indications for RSA continue to expand, it is imperative to accurately track the rates and types of complications to justify its cost and increased indications.

Preoperative external rotation deficit does not predict poor outcomes or lack of improvement after reverse total shoulder arthroplasty

INTRODUCTION

The purpose was to compare postoperative outcomes and functional improvement between patients with preoperative aER deficits vs. preserved aER function.

RESULTS

There were 115 patients in the <0° aER group and 314 in the ≥30° aER group. Preoperative patients in the <0° group were worse for all measures except subjective pain while post-operatively, they had significantly greater improvement for all measures of motion. Postoperatively, both groups achieved comparable scores for forward elevation, pain, SST and ASES.

CONCLUSION

This study demonstrates that patients with a complete aER deficit can recover substantial and comparable function after RTSA.

The influence of preoperative external rotation weakness or stiffness on reverse total shoulder arthroplasty

Background

Some reverse total shoulder arthroplasty (rTSA) patients may have limited preoperative external rotation (ER) because of stiffness or weakness. Currently it is not known if this affects their clinical outcome or if their ER will improve after surgery.

Methods

A multicenter shoulder arthroplasty database was queried to analyze patients undergoing a primary rTSA using a single prosthesis design featuring a medial glenoid–lateral humerus. Their pre- and postoperative range of motion was evaluated in addition to 5 outcome measures. Patients with limited preoperative ER due to weakness or stiffness were compared to patients with normal preoperative range of motion. The following questions were asked: (1) Does a preoperative ER deficit impact the postoperative outcome? (2) Do patients with preoperative ER deficits due to stiffness or weakness regain ER after rTSA? and (3) Does a preoperative ER lag sign predict a poor outcome?

Results

608 patients were included in this study. Active external rotation (preoperative/postoperative) was as follows for the 3 patient groups: Normal patients (45°/44°), Stiff (–4°/30°), and Weak (16°/32°). Weak patients had a preoperative ER lag of 30°, which improved by 16° after surgery. The clinical outcome scores for all 3 groups improved after rTSA. Stiff patients had significantly greater improvement than Weak and Normal patients. Outcome scores were equivalent for Normal and Stiff patients. Weak patients tended to have slightly lower outcome scores.

Conclusions

Patients with limited preoperative ER can obtain a good clinical result with rTSA using a medial glenoid–lateral humerus prosthesis, ER range of motion can improve after rTSA, and stiff patients have a particularly good prognosis for recovery.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Optimal glenosphere size cannot be determined by patient height

BACKGROUND

Glenosphere size remains 1 surgeon-controlled variable that can affect patient outcomes following reverse shoulder arthroplasty (RSA). There remains no objective criterion to guide surgeons in choosing glenosphere size. This study's purpose was to evaluate range of motion (ROM) as a function of patient height and glenosphere size to determine the optimal glenosphere size based on patient height.

METHODS

We retrospectively reviewed 589 primary RSAs from a multicenter shoulder arthroplasty database of a single RSA system with multiple glenosphere sizes. Shoulders were separated into groups based on glenosphere size (38 or 42 mm). Predictive accuracy was calculated in relation to height and sex for predicting glenosphere size. Improvements in active ROM and patient-reported outcome measures (PROMs) were compared based on glenosphere size as a function of height.

RESULTS

Logistic regression analysis demonstrated a strong association of height and sex with surgeon selection of glenosphere size, with shorter heights preferentially treated with 38-mm glenospheres and taller heights with 42-mm glenospheres. There were no statistically significant interaction effects of glenosphere size and height on improvements in ROM or PROMs. These results indicate that for a given glenosphere size, there is not an optimal height range to maximize improvements in postoperative outcome measures.

DISCUSSION

Height and sex are highly correlated with a surgeon's choice of glenosphere size. However, on the basis of improvements in ROM and PROMs, no recommendation can be made for surgeons to select a particular glenosphere size based on a patient's height. Surgeons should consider other variables when selecting a glenosphere size.

Advances and Update on Reverse Total Shoulder Arthroplasty

PURPOSE OF REVIEW

Reverse total shoulder arthroplasty (RTSA) is a procedure that has been increasingly utilized since its inception over 20 years ago. The purpose of this review is to present the most up to date practice and advances to the RTSA literature from the last 5 years.

RECENT FINDINGS

Recent literature on RTSA has focused on identifying complications, maximizing outcomes, and determining its cost-effectiveness. RTSA has become a valuable tool in the treatment of various shoulder pathologies from fractures to massive-irreparable rotator cuff tears. Maximizing outcomes, proper patient counseling, and limiting complications are vital to a successful procedure. RTSA can be a difficult procedure; however, when utilized appropriately, it can be an invaluable tool in the orthopedic surgeon's armament. Recent evidence suggests, more and more, that RTSA not only provides value to the patient, but it is also cost-effective.

Preoperative parameters that predict postoperative patient-reported outcome measures and range of motion with anatomic and reverse total shoulder arthroplasty

Background

Preoperative factors that most influence postoperative outcomes of both anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) are unknown. The purpose of this study was to identify the preoperative parameters that significantly influence postoperative outcomes of aTSA and rTSA.

Methods

The outcomes of 1089 aTSA patients and 1332 rTSA patients (mean follow-up period, 49 months) from an international registry with a single platform system were analyzed. A multiple linear regression model with backward stepwise selection identified the preoperative parameters that were significant predictors of postoperative clinical outcome metric scores and motion measures for both rTSA and aTSA.

Results

For both aTSA and rTSA patients, numerous preoperative parameters that influence postoperative outcomes were identified. Greater postoperative range of motion (ROM) was significantly influenced by greater preoperative ROM. For aTSA, greater postoperative American Shoulder and Elbow Surgeons (ASES) scores were significantly influenced by greater preoperative ASES scores, no history of shoulder surgery, and the presence of greater preoperative active external rotation. For rTSA, greater postoperative ASES scores were significantly influenced by greater preoperative ASES scores, no history of shoulder surgery, no history of tobacco use, less preoperative passive external rotation, and greater preoperative active external rotation.

Conclusions

This study quantified the preoperative predictors of postoperative clinical outcome metric scores and ROM for both aTSA and rTSA. Numerous significant associations were identified, including demographic and comorbidity risk factors. These associations may be helpful for surgeons to consider when counseling patients regarding aTSA versus rTSA and to establish more accurate expectations prior to surgery.

Reverse Total Shoulder Arthroplasty: Implant Design Considerations

PURPOSE OF REVIEW

Our understanding of the reverse total shoulder arthroplasty (RTSA) has grown exponentially since Grammont first introduced his design in 1985. There are a multitude of implant-related variables to consider when performing RTSA. The purpose of this article is to provide a review of these design considerations.

RECENT FINDINGS

Current literature demonstrates that the traditional Grammont prosthesis has over 90% survivorship at 10 years. Despite these promising results, there have been concerns raised over the significant rate of scapular notching observed. As a result, the traditional RTSA design has been modified to minimize this complication and maximize impingement-free motion. Modern RTSA designs with a cementless, curved, short-stemmed eccentric onlay humeral component combined with a large, lateralized glenosphere placed in 10° of inferior tilt with > 3.5 mm of inferior overhang have been found to provide excellent results. However, all implant design features must be considered on a case-by-case basis to optimize outcome for each patient. Humeral and glenoid implant design variables have evolved as the biomechanics of RTSA have been further elucidated. Consideration of these variables allows the surgeon to maximize joint efficiency, improve impingement-free range of motion, decrease the risk of scapular notching, preserve bone stock, and minimize the risk of instability.

Impact of Age and Subscapularis Tendon Reparability on Return to Recreational Sports Activities and 2-Year Outcomes After Reverse Total Shoulder Arthroplasty

Background:

As the indications for reverse total shoulder arthroplasty (RTSA) have continued to expand, the average age of patients undergoing RTSA has decreased.

Purpose/Hypothesis:

The purpose of this study was to report the minimum 2-year outcomes after RTSA and to evaluate the impact of surgical variables on outcomes. We hypothesized that younger patients, patients with larger glenosphere, and patients with irreparable subscapularis tendons would experience worse subjective patient-reported outcome scores (PROS) and that younger patients and those with a reparable subscapularis would demonstrate a higher rate of return to recreational sports activities.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients who underwent RTSA by a single surgeon between November 2005 and September 2014 were considered for this study. Patient characteristics, surgical details, PROS, and rates of return to recreational sports activity were prospectively collected and retrospectively reviewed. We assessed correlations between PROS and both patient age and subscapularis reparability. PROS collected included the American Shoulder and Elbow Surgeons (ASES) score, Short Form 12 (SF-12), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score, Single Assessment Numeric Evaluation (SANE), and postoperative patient satisfaction.

Results:

A total of 110 patients with an average age of 68.0 years (range, 45-87 years) were included. Minimum 2-year follow-up was obtained in 94 patients (85.4%), with a mean follow-up of 3.6 years (range, 2.0-9.3 years). The subscapularis was reparable in 58 patients (57.4%). All PROS significantly improved from pre- to postoperatively (P < .001). The median patient postoperative satisfaction was 9 out of 10 (range, 1-10). Increasing patient age was correlated with significant improvements in QuickDASH and ASES scores. Postoperatively, 76.1% (67/88) of patients were able to return to recreational sports activity. However, of those who did return, 68.2% indicated that they had to modify their activity in some way. Glenosphere size was not significantly associated with PROS or the rate of return to recreational sports activity, but patients with reparable subscapularis tendons demonstrated higher PROS and return to activity rates.

Conclusion:

Patients who had a reparable subscapularis tendon showed a significantly higher rate of return to recreational sports activity than patients who had a irreparable subscapularis tendon. Older age was correlated with greater improvement in several, although not all, patient-reported outcome measures. Glenosphere size was not significantly associated with higher PROS or rate of return to recreational sports activity.