Outpatient vs. inpatient total shoulder arthroplasty: complication rates, clinical outcomes, and eligibility parameters.

Background: Improvements in total shoulder arthroplasty (TSA), fast-track surgery, multimodal anesthesia, and rehabilitation protocols have opened up the possibility of outpatient care that is now routinely practiced at our European institution. The first objective of this study was to define the TSA outpatient population and to verify that outpatient management of TSA does not increase the risk of complications. The second objective was to determine patient eligibility parameters and the third was to compare functional outcomes and identify influencing factors. Methods: The study included 165 patients who had primary TSA (106 outpatient and 59 inpatient procedures). The operative technique was the same for both groups. Demographics, complications, readmissions, and revisions were collected. American Society of Anesthesiologists, Constant, American Shoulder and Elbow Surgeons, University of California Los Angeles shoulder, and Shoulder Pain and Disability Index scores were obtained preoperatively and at 1.5, 6, and 12 months postoperatively. Satisfaction and visual analog scale pain scores also were documented. Statistical analysis was completed using multivariate linear regression. Results: Outpatients were significantly younger and had lower American Society of Anesthesiologists scores than inpatients. The rates of complications, readmissions, and reoperations were not significantly different between groups. Outpatient surgery was not an independent risk factor for complications. At 1.5 months, better outcomes were noted in the outpatient group for all scores, and these reached statistical significance. Distance to home, dominant side, operative time, and blood loss were not associated with functional results. Multivariate analysis demonstrated that outpatient care was significantly associated with improved scores at 1.5 months and did not affect functional outcomes at 6 and 12 months. Conclusion: This study reports the results of routine outpatient TSA within a European healthcare system. TSA performed in an outpatient setting was not an independent risk factor for complications and seemed to be an independent factor in improving early functional results.

Stratification of the Minimal Clinically Important Difference, Substantial Clinical Benefit, and Patient Acceptable Symptomatic State after Total Shoulder Arthroplasty by Implant Type, Preoperative Diagnosis, and Sex.

BACKGROUND: Clinical significance, as opposed to statistical significance, has increasingly been utilized to evaluate outcomes after total shoulder arthroplasty (TSA). The purpose of this study was to identify thresholds of the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for TSA outcome metrics and determine if these thresholds are influenced by prosthesis type (anatomic or reverse TSA), sex, or preoperative diagnosis. METHODS: A prospectively collected international multicenter database inclusive of 38 surgeons was queried for patients receiving a primary aTSA or rTSA between 2003 and 2021. Prospectively, outcome metrics including ASES, shoulder function score (SFS), SST, UCLA, Constant, VAS Pain, shoulder arthroplasty smart (SAS) score, forward flexion, abduction, external rotation, and internal rotation was recorded preoperatively and at each follow-up. A patient satisfaction question was administered at each follow-up. Anchor-based MCID, SCB, and PASS were calculated as defined previously overall and according to implant type, preoperative diagnosis, and sex. The percentage of patients achieving thresholds was also quantified. RESULTS: A total of 5,851 total shoulder arthroplasties including aTSA (n=2,236) and rTSA (n=3,615) were included in the study cohort. The following were identified as MCID thresholds for the overall (aTSA + rTSA irrespective of diagnosis or sex) cohort: VAS Pain (-1.5), SFS (1.2), SST (2.1), Constant (7.2), ASES (13.9), UCLA (8.2), SPADI (-21.5), and SAS (7.3), Abduction (13°), Forward elevation (16°), External rotation (4°), Internal rotation score (0.2). SCB thresholds for the overall cohort were: VAS Pain (-3.3), SFS (2.9), SST 3.8), Constant (18.9), ASES (33.1), UCLA (12.3), SPADI (-44.7), and SAS (18.2), Abduction (30°), Forward elevation (31°), External rotation (12°), Internal rotation score (0.9). PASS thresholds for the overall cohort were: VAS Pain (0.8), SFS (7.3), SST (9.2), Constant (64.2), ASES (79.5), UCLA (29.5), SPADI (24.7), and SAS (72.5), Abduction (104°), Forward elevation (130°), External rotation (30°), Internal rotation score (3.2). MCID, SCB, and PASS thresholds varied depending on preoperative diagnosis and sex. CONCLUSION: MCID, SCB, and PASS thresholds vary depending on implant type, preoperative diagnosis, and sex. A comprehensive understanding of these differences as well as identification of clinically-relevant thresholds for legacy and novel metrics is essential to assist surgeons in evaluating their patient's outcomes, interpreting the literature, and counseling their patients preoperatively regarding expectations for improvement. Given that PASS thresholds are fragile and vary greatly depending on cohort variability, caution should be exercised in conflating them across different studies.

Utility of Superior Augments in Reverse Shoulder Arthroplasty (Exactech, Equinoxe GPS) without Significant Glenoid Deformity.

INTRODUCTION: Superior augment use may help avoid superior tilt while minimizing removal of inferior glenoid bone. Therefore, our goal is to compare superior augments versus no augment baseplates in RSA for patients with rotator cuff dysfunction and no significant superior glenoid erosion. METHODS: A multicenter retrospective analysis of 145 patients who underwent RSA with intraoperative navigation (Exactech, Equinoxe GPS) and three-year follow-up (mean 32-month follow-up, range 20 to 61 months) who had preoperative superior inclination less than 10 degrees and retroversion less than 15 degrees. Patient demographics, radiographic measurements, surgical characteristics, patient-reported outcomes at preoperative and postoperative visit closest to three years, and adverse events at final follow-up were obtained. Operative time, planned inclination, and planned version of the baseplate were obtained. Chi-square test used to compare categorical variables and student t-test used to compare augment and no augment cohorts. RESULTS: The study population consisted of 54 superior augment patients and 91 no augment patients. The augment cohort had lower BMI (27.2 vs. 29.4, p-0.023), higher native superior inclination (5.9 vs. 1.4 degrees, p<0.001). No difference between the augment and no augment cohorts was found regarding age (p=0.643), gender (p=0.314), medical comorbidities (p>0.05), surgical indication (p=0.082), and native glenoid version (p=0.564). The augment cohort had higher internal rotation score (4.6 vs. 3.9, p=0.023), all remaining ROM and PROs preoperatively were not significantly different. At final follow-up, active ROM in all planes was not different between the cohorts. Regarding PROs, the postoperative SAS score was significantly higher (78.0 vs. 73.6, p=0.042), and ASES score trended towards higher (83.6 vs. 77.5, p=0.063) in the augment cohort. The augment cohort had significantly lower proportion of patients planned to have superior baseplate tilt (1.9% vs. 14.3%, p=0.012), and had greater mean inclination correction (6.3 vs. 1.3 degrees, p<0.001), compared to no augment cohort. Adverse events were rare, and there was no significant difference found between the augment and no augment cohorts (5.6% vs. 3.3%, p=0.509). DISCUSSION: Superior augmented baseplate in RSA with minimal superior glenoid erosion is associated with similar ROM and adverse events with somewhat improved postoperative PROs compared to non-augmented baseplates at 3-year follow-up. Additionally, superior augments resulted in a greater proportion of baseplates planned to avoid superior tilt, and trended toward shorter operative times. Further investigation of long-term glenoid baseplate loosening is imperative to fully understand the cost-effectiveness of superior augments in the setting of minimal glenoid deformity.

Two-year minimum survivorship and radiographic analysis of a pressfit short humeral stem for total shoulder arthroplasty.

Background: Newer generation humeral stem designs in total shoulder arthroplasty (TSA) are trending towards shorter lengths and uncemented fixation. The goal of this study is to report a 2-yr minimum clinical and radiographic outcomes of an uncemented short-stem press-fit humeral stem in anatomic total shoulder arthroplasty (ATSA) and reverse total shoulder arthroplasty (RTSA). Methods: A retrospective multicenter database review was performed of all patients who received an uncemented short-length press-fit humeral stem (Equinoxe Preserve humeral stem, Exactech, Inc., Gainesville, FL, USA) in ATSA and RTSA with a minimum two-year follow-up. The primary outcome was the prevalence of humeral stems at risk of radiographic loosening. Secondary outcomes included evaluation of functional outcome scores and prevalence of revision TSA for humeral stem loosening. Two blinded observers performed radiographic analyses, which included humeral stem alignment, canal filling ratio, radiolucent lines, stress shielding (calcar and greater tuberosity), and changes in component position (subsidence and stem shift). At risk stems were defined by the presence of one or more of the following: humeral stem with shifting or subsidence, scalloping of the humeral cortex, or radiolucent lines measuring 2 mm or greater in 3 or more zones. Results: 287 patients (97 ATSA and 190 RTSA) were included in this study. The mean follow-up was 35.9 (±6.1) months. There were significant improvements for all functional outcome scores (P < .05), range of motion (P < .05), and visual analogue pain scale pain (P < .05). The prevalence of humeral stem at risk of radiographic loosening was 1% in the ATSA group (1/97) and 18.4% in the RTSA group (35/190). Calcar resorption was seen in 34% of ATSA and 19% of RTSA, with severe resorption in 12.4% of ATSA and only 3.2% of RTSA. Greater tuberosity resorption was present in 3.1% of ATSA and 7.9% of RTSA. The mean canal filling ratio was 50.2% (standard deviation 11.2%). Using logistic regression, a significant positive correlation between canal filling ratio and stress shielding (P < .01) was seen for both calcar and tuberosity stress shielding. The revision surgery rate was 0% in ATSA compared to 1.6% in RTSA. Conclusion: This retrospective study demonstrates a low revision rate and low prevalence of humeral stems at risk of radiographic loosening at two years with a press-fit short-stem humeral design in ATSA. Physiologic subsidence of humeral stems can account for higher prevalence of humeral stems at radiographic risk of loosening in RTSA compared to ATSA.

Impact of accumulating risk factors on the incidence of dislocation after primary reverse total shoulder arthroplasty using a medial glenoid-lateral humerus onlay prosthesis.

BACKGROUND: The aim of this study was to facilitate preoperative identification of patients at risk for dislocation after reverse total shoulder arthroplasty (rTSA) using the Equinoxe rTSA prosthesis (medialized glenoid, lateralized onlay humerus with a 145° neck-shaft angle) and quantify the impact of accumulating risk factors on the occurrence of dislocation. METHODS: We retrospectively analyzed 10,023 primary rTSA patients from an international multicenter database of a single platform shoulder prosthesis and quantified the dislocation rate associated with multiple combinations of previously identified risk factors. To adapt our statistical results for prospective identification of patients most at-risk for dislocation, we stratified our data set by multiple risk factor combinations and calculated the odds ratio for each cohort to quantify the impact of accumulating risk factors on dislocation. RESULTS: Of the 10,023 primary rTSA patients, 136 (52 female, 83 male, 1 unknown) were reported to have a dislocation for a rate of 1.4%. Patients with zero risk factors were rare, where only 12.7% of patients (1268 of 10,023) had no risk factors, and only 0.5% of these (6 of 1268) had a report of dislocation. The dislocation rate increased in patient cohorts with an increasing number of risk factors. Specifically, the dislocation rate increased from 0.9% for a patient cohort with 1 risk factor to 1.0% for 2 risk factors, 1.6% for 3 risk factors, 2.7% for 4 risk factors, 5.3% for 5 risk factors, and 7.3% for 6 risk factors. Stratifying dislocation rate by multiple risk factor combinations identified numerous cohorts with either an elevated risk or a diminished risk for dislocation. DISCUSSION: This multicenter study of 10,023 rTSA patients demonstrated that 1.4% of the patients experienced dislocation with one specific medialized glenoid-lateralized humerus onlay rTSA prosthesis. Stratifying patients by multiple combinations of risk factors demonstrated the impact of accumulating risk factors on the incidence of dislocation. rTSA patients with the greatest risk of dislocation were those of male sex, age ≤67 years at the time of surgery, patients with body mass index ≥31, patients who received cemented humeral stems, patients who received glenospheres having a diameter >40 mm, and/or patients who received expanded or laterally offset glenospheres. Patients with these risk factors who are considering rTSA using a medial glenoid-lateral humerus should be made aware of their elevated dislocation risk profile.

Prognostic value of the Walch classification for patients before and after shoulder arthroplasty performed for osteoarthritis with an intact rotator cuff.

BACKGROUND: The Walch classification is commonly used by surgeons when determining the treatment of osteoarthritis (OA). However, its utility in prognosticating patient clinical state before and after TSA remains unproven. We assessed the prognostic value of the modified Walch glenoid classification on preoperative clinical state and postoperative clinical and radiographic outcomes in total shoulder arthroplasty (TSA). METHODS: A prospectively collected, multicenter database for a single-platform TSA system was queried for patients with rotator cuff-intact OA and minimum 2 year follow-up after anatomic (aTSA) and reverse TSA (rTSA). Differences in patient-reported outcome scores (Simple Shoulder Test, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Shoulder Pain and Disability Index, visual analog scale for pain, Shoulder Function score), combined patient-reported and clinical-input scores (Constant, University of California-Los Angeles shoulder score, Shoulder Arthroplasty Smart Score), active range of motion values (forward elevation [FE], abduction, external rotation [ER], internal rotation [IR], and radiographic outcomes (humeral and glenoid radiolucency line rates, scapula notching rate) were stratified and compared by glenoid deformity type per the Walch classification for aTSA and rTSA cohorts. Comparisons were performed to assess the ability of the Walch classification to predict the preoperative, postoperative, and improved state after TSA. RESULTS: 1008 TSAs were analyzed including 576 aTSA and 432 rTSA. Comparison of outcomes between Walch glenoid types resulted in 15 pairwise comparisons of 12 clinical outcome metrics, yielding 180 total Walch glenoid pairwise comparisons for each clinical state (preoperative, postoperative, improvement). Of the 180 possible pairwise Walch glenoid type and metric comparisons studied for aTSA and rTSA cohorts, <6% and <2% significantly differed in aTSA and rTSA cohorts, respectively. Significant differences based on Walch type were seen after adjustment for multiple pairwise comparisons in the aTSA cohort for FE and ER preoperatively, the Constant score postoperatively, and for abduction, FE, ER, Constant score, and SAS score for pre- to postoperative improvement. In the rTSA cohort, significant differences were only seen in abduction and Constant score both postoperatively and for pre- to postoperative improvement. There were no statistically significant differences in humeral lucency rate, glenoid lucency rate (aTSA), scapular notching rate (rTSA), complication rates, or revision rates between Walch glenoid types after TSA. CONCLUSION: Although useful for describing degenerative changes to the glenohumeral joint, we demonstrate a weak association between preoperative glenoid morphology according to the Walch classification and clinical state when evaluating patients undergoing TSA for rotator cuff-intact OA. Alternative glenoid classification systems or predictive models should be considered to provide more precise prognoses for patients undergoing TSA for rotator cuff-intact OA.

Comparison of long-term clinical and radiological outcomes for cemented keel, cemented peg, and hybrid cage glenoids with anatomical total shoulder arthroplasty using the same humeral component.

Aims: The aim of this study was to longitudinally compare the clinical and radiological outcomes of anatomical total shoulder arthroplasty (aTSA) up to long-term follow-up, when using cemented keel, cemented peg, and hybrid cage peg glenoid components and the same humeral system. Methods: We retrospectively analyzed a multicentre, international clinical database of a single platform shoulder system to compare the short-, mid-, and long-term clinical outcomes associated with three designs of aTSA glenoid components: 294 cemented keel, 527 cemented peg, and 981 hybrid cage glenoids. Outcomes were evaluated at 4,746 postoperative timepoints for 1,802 primary aTSA, with a mean follow-up of 65 months (24 to 217). Results: Relative to their preoperative condition, each glenoid cohort had significant improvements in clinical outcomes from two years to ten years after surgery. Patients with cage glenoids had significantly better clinical outcomes, with higher patient-reported outcome scores and significantly increased active range of motion, compared with those with keel and peg glenoids. Those with cage glenoids also had significantly fewer complications (keel: 13.3%, peg: 13.1%, cage: 7.4%), revisions (keel: 7.1%, peg 9.7%, cage 3.5%), and aseptic glenoid loosening and failure (keel: 4.7%, peg: 5.8%, cage: 2.5%). Regarding radiological outcomes, 70 patients (11.2%) with cage glenoids had glenoid radiolucent lines (RLLs). The cage glenoid RLL rate was 3.3-times (p < 0.001) less than those with keel glenoids (37.3%) and 4.6-times (p < 0.001) less than those with peg glenoids (51.2%). Conclusion: These findings show that good long-term clinical and radiological outcomes can be achieved with each of the three aTSA designs of glenoid component analyzed in this study. However, there were some differences in clinical and radiological outcomes: generally, cage glenoids performed best, followed by cemented keel glenoids, and finally cemented peg glenoids.

Two-year clinical outcomes and complication rates in anatomic and reverse shoulder arthroplasty implanted with Exactech GPS intraoperative navigation.

INTRODUCTION: We compared the 2-year clinical outcomes of both anatomic and reverse total shoulder arthroplasty (ATSA and RTSA) using intraoperative navigation compared to traditional positioning techniques. We also examined the effect of glenoid implant retroversion on clinical outcomes. HYPOTHESIS: In both ATSA and RTSA, computer navigation would be associated with equal or better outcomes with fewer complications. Final glenoid version and degree of correction would not show outcome differences. MATERIAL AND METHODS: A total of 216 ATSAs and 533 RTSAs were performed using preoperative planning and intraoperative navigation with a minimum of 2-year follow-up. Matched cohorts (2:1) for age, gender, and follow-up for cases without intraoperative navigation were compared using all standard shoulder arthroplasty clinical outcome metrics. Two subanalyses were performed on navigated cases comparing glenoids positioned greater or less than 10° of retroversion and glenoids corrected more or less than 15°. RESULTS: For ASTA, no statistical differences were found between the navigated and non-navigated cohorts for postoperative complications, glenoid implant loosening, or revision rate. No significant differences were seen in any of the ATSA outcome metrics besides higher internal and external rotation in the navigated cohort. For RTSA, the navigated cohort showed an ARR of 1.7% (95% CI 0%, 3.4%) for postoperative complications and 0.7% (95% CI 0.1%, 1.2%) for dislocations. No difference was found in the revision rate, glenoid implant loosening, acromial stress fracture rates, or scapular notching. Navigated RTSA patients demonstrated significant improvements over non-navigated patients in internal rotation, external rotation, maximum lifting weight, the Simple Shoulder Test (SST), Constant, and Shoulder Arthroplasty Smart (SAS) scores. For the navigated subcohorts, ATSA cases with a higher degree of final retroversion showed significant improvement in pain, Constant, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), SST, University of California-Los Angeles shoulder score (UCLA), and Shoulder Pain and Disability Index (SPADI) scores. No significant differences were found in the RTSA subcohort. Higher degrees of version correction showed improvement in external rotation, SST, and Constant scores for ATSA and forward elevation, internal rotation, pain, SST, Constant, ASES, UCLA, SPADI, and SAS scores for RTSA. CONCLUSION: The use of intraoperative navigation shoulder arthroplasty is safe, produces at least equally good outcomes at 2 years as standard instrumentation does without any increased risk of complications. The effect of final implant position above or below 10° of glenoid retroversion and correction more or less than 15° does not negatively impact outcomes.

Aseptic glenoid baseplate loosening after reverse total shoulder arthroplasty with a single prosthesis.

BACKGROUND: Early reverse total shoulder arthroplasty (rTSA) designs had high failure rates, mainly from loosening of the glenoid baseplate. The purpose of this study was to determine the incidence of aseptic glenoid baseplate loosening after primary rTSA using a contemporary medialized glenoid-lateralized humerus system and identify significant risk factors associated with loosening. METHODS: A total of 7162 patients underwent primary rTSA with a single-platform rTSA system between April 2007 and August 2021; of these primary rTSA patients, 3127 with a minimum 2-year follow-up period were identified. Patients with aseptic glenoid baseplate loosening were compared with all other primary rTSA patients without loosening. Univariate and multivariate analyses were performed to compare these cohorts and identify the demographic characteristics, comorbidities, operative parameters, and implant characteristics associated aseptic glenoid loosening after rTSA. Odds ratios (ORs) were calculated for each significant risk factor and for multiple combinations of risk factors. RESULTS: Irrespective of minimum follow-up, 53 of 7162 primary rTSA shoulders (31 female and 22 male shoulders) experienced aseptic glenoid loosening, for an overall rate of 0.74%. At latest (2-year minimum) follow-up, 30 of 3127 patients experienced aseptic glenoid loosening and showed significantly lower clinical scores, function, and active range of motion and higher pain scores than patients without loosening. Univariate analysis identified rheumatoid arthritis (P = .029; OR, 2.74) and diabetes (P = .028; OR, 1.84) as significant risk factors for aseptic glenoid loosening after rTSA, and multivariate analysis identified Walch glenoid types B2 (P = .002; OR, 4.513) and B3 (P = .002; OR, 14.804), use of expanded lateralized glenospheres (P = .025; OR, 2.57), and use of augmented baseplates (P = .001; OR, 2.50) as significant risk factors. CONCLUSION: The incidence of aseptic glenoid baseplate loosening was 0.74% for the evaluated medialized glenoid-lateralized humerus rTSA system. Numerous risk factors for aseptic loosening were identified, including rheumatoid arthritis, diabetes, Walch type B2 and B3 glenoids, posteriorly-superiorly augmented baseplates, and expanded lateralized glenospheres. Finally, analysis of multiple combinations of risk factors identified patients and implant configurations with the greatest risk of aseptic glenoid loosening.

Impact of accumulating risk factors on the acromial and scapular fracture rate after reverse total shoulder arthroplasty with a medialized glenoid-lateralized humerus onlay prosthesis.

BACKGROUND: Identifying risk factors for acromial and scapular fractures improves our understanding about which variables are relevant to these fracture complications; however, these data are difficult to integrate into clinical practice because the majority of reverse total shoulder arthroplasty (rTSA) patients have ≥1 risk factor. The goal of this study was to better facilitate preoperative identification of patients at risk of acromial and scapular fractures and quantify the impact of accumulating risk factors on the incidence of fracture. METHODS: We retrospectively analyzed 9079 rTSA patients from a multicenter database of rTSA procedures performed with a single medialized glenoid-lateralized humerus onlay rTSA prosthesis to quantify the rate of acromial and scapular fractures. Univariate and multivariate analyses were performed to identify risk factors for fracture. Next, we quantified the number of patients with 1 or multiple significant risk factors for fracture. Finally, to facilitate preoperative identification of patients most at risk of fracture, we stratified our data set using multiple combinations of age, sex, and diagnosis risk factors and calculated the odds ratio for each cohort to quantify the impact of accumulating risk factors on the incidence of fracture. RESULTS: A fracture of the acromion or scapula was radiographically identified in 138 of 9079 patients, for a rate of 1.52%. Patients with fractures were more likely to be older, of female sex, to have a diagnosis of rheumatoid arthritis and/or cuff tear arthropathy, and were less likely to have a diagnosis of diabetes. Eighty-five percent of rTSA patients had ≥1 fracture risk factor. Individually, age, sex, or diagnosis failed to identify any patient cohort with an odds ratio >2.5. Use of multiple combinations of patient risk factors refined the identification of at-risk patients better than any individual risk factor or 2-risk factor combination and demonstrated that the patients with the greatest fracture risk were female patients with a rheumatoid arthritis diagnosis who were aged >70, >75, and >80 years. CONCLUSION: This 9079-rTSA multicenter study demonstrated that 1.52% of patients experienced acromial and/or scapular fractures with a single medialized glenoid-lateralized humerus onlay rTSA prosthesis. Our analysis identified numerous risk factors and quantified the impact of accumulating risk factors on fracture incidence. Patients who are considering rTSA and who have these age, sex, and diagnosis risk factors should be made aware of their elevated complication risk.

Longitudinal analysis of shoulder arthroplasty utilization, clinical outcomes, and value: a comparative assessment of changes in improvement over 15 years with a single platform shoulder prosthesis.

BACKGROUND: The goal of this longitudinal analysis of anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) utilization from 2007 to 2021 is to quantify changes in clinical outcomes, cost, and value, resulting from the introduction and adoption of new shoulder arthroplasty (SA) technologies. METHODS: We analyzed an international database of a single SA prosthesis (Equinoxe; Exactech, Inc.; Gainesville, FL, USA) for all clinical sites that have continuously enrolled cases from 2007 to 2021 to compare changes in primary aTSA and primary rTSA utilization and outcomes across 3, 5-year cohorts based upon the date of implantation. A value analysis was conducted across the 5-year implantation cohorts, with value measured by the ratio of each postoperative outcome measure at 24-36 months and 36-60 months after surgery, and the average implant selling price each year for the U.S. sites in constant 2007 U.S. dollars. These measures of value were compared between cohorts to quantify the impact of new technology introduced over the study period. RESULTS: A dramatic increase in rTSA utilization was observed across the 6 sites over the 15-year study period, along with a rapid adoption of new aTSA and rTSA technologies. The average patient receiving primary aTSA and primary rTSA changed over the 15-year study period, with significant shifts in diagnosis, comorbidities, and preoperative functional status. A comparison of postoperative results demonstrated that both aTSA and rTSA clinical and radiographic outcomes showed improvement relative to 2007-2011. Over this 15-year study period, the average aTSA implant selling price has been relatively stable while the average rTSA implant selling price has significantly declined. As a result, the value associated with the Equinoxe rTSA significantly increased for nearly every outcome measure at 24-36 months and 36-60 months after surgery, while value associated with the Equinoxe aTSA stayed relatively constant from 2007 to 2021. CONCLUSION: Our 6042-patient longitudinal analysis quantified numerous changes in utilization, outcomes, and value across 6 clinical sites over the 15-year study period. Rapid adoption of new aTSA and rTSA technologies was observed and clinical and radiographic outcomes improved relative to 2007-2011. These clinical improvements, in combination with steady aTSA and declining rTSA implant prices, have driven rTSA value to continuously increase while aTSA value has been maintained at a high-level over the 15-year study period with this particular SA system, even when considering the cost and adoption of new technologies.

Does isolated glenosphere lateralization affect outcomes in reverse shoulder arthroplasty?

INTRODUCTION: While lateralization of the glenohumeral center of rotation during reverse shoulder arthroplasty (RSA) has benefits of maintaining tension on the remaining rotator cuff and decreasing implant impingement on the glenoid, few clinical studies have evaluated the isolated effect of glenoid lateralization in RSA. The purpose of this study was to evaluate if clinical outcomes are affected by isolated glenosphere lateralization using a single implant design. METHODS: A retrospective review from a multicenter shoulder arthroplasty research database was performed between 2011 and 2018 using a single implant system to perform this case-controlled study. Inclusion criteria included primary RSAs with adequate preoperative and postoperative active and passive range of motion (ROM) measurements, outcome scores, and a minimum two-year follow-up. Revision shoulder arthroplasties and RSA for fractures were excluded from analysis. 102 RSAs (61 females, 41 males) using a +4mm lateralized glenosphere were compared to 102 sex, age, and glenosphere diameter matched control shoulders with standard glenospheres (whose center of rotation (CoR) is 2mm lateral to the glenoid fossa). The mean age at surgery was 70.4 years. Mean follow up was 43.6+18.9 months. All RSAs were performed with the same implant system (Equinoxe, Exactech, Gainesville, FL). Clinical outcome measures included ROM, ASES, Constant, UCLA, SST, SPADI scores, and VAS pain scores. We used the chi-squared test and Fisher exact test for bivariate analysis and the student t-test for continuous variables. RESULTS: Both groups were of similar average age and follow-up. They also had comparable rates of prior surgery and comorbidities. The lateralized glenosphere group had a slightly higher BMI (31.2 vs. 29.2, p=0.04). Both groups demonstrated significant improvements in all outcome scores that exceeded the MCID and the SCB. The groups demonstrated similar preoperative, postoperative and improvements in ROM as well as outcome scores. The overall complication rate was similar between groups (4% in lateralized and 5% in controls, p=0.73). Scapular or acromial fractures differences were not statistically significant between groups (1% in lateralized group vs. 3% in standard group, p=0.31). Scapular notching was more frequent in the standard group compared to the lateralized group (9% vs. 2%, p=0.03). CONCLUSION: In a medialized glenosphere/lateralized humerus design, a +4mm lateralized glenosphere provided no significant advantage in postoperative pain, ROM, or outcome scores. However, lateralized glenospheres did demonstrate significantly lower scapular notching rates. LEVEL OF EVIDENCE: III; retrospective cohort comparison; treatment study.

Comparison of Reverse and Anatomic Total Shoulder Arthroplasty in Patients With an Intact Rotator Cuff and No Previous Surgery.

INTRODUCTION: This study's purpose is to compare clinical and radiographic outcomes of primary anatomic total shoulder arthroplasty (aTSA) and primary reverse total shoulder arthroplasty (rTSA) patients with osteoarthritis (OA) and an intact rotator cuff with no previous history of shoulder surgery using a single platform TSA system at a minimum follow-up of 2 years. METHODS: A total of 370 aTSA patients and 370 rTSA patients matched for age, sex, and length of follow-up from an international multi-institutional Western Institutional Review Board approved registry with a minimum 2-year follow-up were reviewed for this study. All patients had a diagnosis of OA, an intact rotator cuff, and no previous shoulder surgery. All patients were evaluated and scored preoperatively and at latest follow-up using six outcome scoring metrics and four active range of motion measurements. RESULTS: Mean follow-up was 41 months, and the mean age was 73 years. Preoperatively, the rTSA patients had lower outcome metrics and less motion. Postoperatively, aTSA and rTSA patients had similar clinical outcomes, motion, and function, with the only exception being greater external rotation in aTSA exceeding the minimal clinically important difference. Pain relief was excellent, and patient satisfaction was high in both groups. Humeral radiolucent lines were similar in both groups (8%). Complications were significantly higher with aTSA (aTSA = 4.9%; rTSA = 2.2%; P = 0.045), but revisions were similar (aTSA = 3.2%; rTSA = 1.4%; P = 0.086). CONCLUSION: At a mean of 41 month follow-up, primary aTSA and rTSA patients with OA and an intact rotator cuff with no previous history of shoulder surgery had similar clinical and radiographic outcomes. Greater external rotation was noted in aTSA patients at follow-up. However, aTSA patients had a significantly greater rate of complications compared with rTSA patients. rTSA is a viable treatment option in patients with an intact rotator cuff and no previous shoulder surgery, offering similar clinical outcomes with a lower complication rate. LEVEL OF EVIDENCE: Level III.

Reverse shoulder arthroplasty with and without baseplate wedge augmentation in the setting of glenoid deformity and rotator cuff deficiency-a multicenter investigation.

INTRODUCTION: Glenoid baseplate augments have recently been introduced as a way of managing glenoid monoplanar or biplanar abnormalities in reverse shoulder arthroplasty (RSA). The purpose of this study is to evaluate the difference in clinical outcomes, complications, and revision rates between augmented and standard baseplates in RSA for rotator cuff arthropathy patients with glenoid deformity. METHODS: A multicenter retrospective analysis of 171 patients with glenoid bone loss who underwent RSA with and without augmented baseplates was performed. Preoperative inclusion criteria included minimum follow-up of 2 years and preoperative retroversion of 15°-30° and/or a beta angle 70°-80°. Version and beta angle were measured on computed tomographic scans, when available, and plain radiographs. Shoulder range of motion (ROM) and patient-reported outcomes were obtained from preoperative and multiple postoperative time points. RESULTS: The study consisted of 84 standard baseplate patients and 87 augmented baseplate patients. The augment cohort had greater mean preoperative glenoid retroversion (17° vs. 9°, P < .001). At >5-year follow-up, the increase in postoperative active abduction (52° vs. 31°, P = .023), forward flexion (58° vs. 35°, P = .020), and internal rotation score (2.8° vs. 1.1°, P = .001) was significantly greater in the augment cohort. Additionally, >5-year follow-up American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score (87.0 ± 16.6 vs. 75.9 ± 22.4, P = .022), Constant score (78.0 ± 9.7 vs. 64.6 ± 15.1, P < .001), and Shoulder Arthroplasty Smart score (81.2 ± 6.5 vs. 71.2 ± 13.6, P = .003) were significantly higher in the augment cohort. Revision rate was low overall, with no difference between the augment and no augment groups (0.7% vs. 3.0%, P = .151). CONCLUSION: In comparing augments to standard nonaugment baseplates in the setting of RSA with glenoid deformity, our results demonstrate greater postoperative improvements in multiple planes of active ROM in the augment cohort. Additionally, the augment cohort demonstrated greater postoperative level and improvement in scores for multiple clinical outcome metrics up to >5 years of follow-up with no difference in complication or revision rates, supporting the use of augmented glenoid baseplates in RSA with glenoid deformity.

Characteristics of anatomic and reverse total shoulder arthroplasty patients who achieve ceiling scores with 3 common patient-reported outcome measures.

BACKGROUND: Legacy shoulder outcome scores have postoperative ceiling scores effects when quantifying clinical outcomes for anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty patients. This study uses data from an international database of a single shoulder prosthesis using data from 30 different clinical sites to quantify and compare the percentage of aTSA and rTSA patients achieving postoperative ceiling scores with multiple outcome measures and defines the patient demographics, comorbidities, implant, and operative parameters associated with ceiling scores for each outcome measure. METHODS: Clinical outcomes for 1817 aTSA and 2635 rTSA patients between 2007 and 2019 were quantified with the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), Simple Shoulder Test (SST), the University of California, Los Angeles (UCLA), Constant, and Shoulder Arthroplasty Smart (SAS) scores. The number of aTSA and rTSA patients with ceiling scores were calculated and sorted into those that achieved ceiling scores with the SST, ASES, and UCLA measures and compared to patients without ceiling scores. A univariate and multivariate analysis then identified the patient demographics, comorbidities, and implant and operative parameters associated with ceiling scores for each outcome measure. RESULTS: aTSA patients achieved ceiling scores at a significantly greater rate than rTSA patients for all outcome measures, except SAS. The SST score was the most susceptible to ceiling scores (aTSA = 43.4%, rTSA = 34.1%, P < .0001), followed by the ASES (aTSA = 23.7%, rTSA = 13.3%, P < .0001) and UCLA (aTSA = 22.2%, rTSA = 10.6%, P < .0001) scores. Ceiling scores were least likely with the Constant (aTSA = 0.4%, rTSA = 0%, P = .0060) and SAS (aTSA = 0.1%, rTSA = 0%, P = .0750) scores. Male patients had a significantly higher ceiling score rate than female patients using the SST and ASES scores, and no differences in ceiling score rates were observed with the UCLA, Constant, or SAS scores. Finally, we identified numerous patient demographic, comorbidity, implant, and operative parameters associated with SST, ASES, and UCLA ceiling scores for aTSA and rTSA patients. DISCUSSION: Postoperative ceiling scores occur at a high rate for aTSA and rTSA patients with the SST, ASES, and UCLA scores. Those most susceptible to ceiling scores are aTSA patients treated with cage glenoids, aTSA patients of lower body mass index, rTSA patients of male gender, rTSA patients with osteoarthritis diagnosis, and rTSA patients with subscapularis repair. Clinical researchers should consider using alternative scores, such as the SAS score, to ensure a more normalized distribution of data and more accurately quantify aTSA and rTSA outcomes.

Anatomic versus reverse shoulder arthroplasty: a mid-term follow-up comparison.

BACKGROUND: Anatomic total shoulder arthroplasty improves pain and function with a reported reoperation rate of approximately 1% per year. With improved glenoid fixation, reverse shoulder arthroplasty implants may outperform anatomic total shoulder arthroplasty. We evaluate the functional outcomes and reoperation rate of anatomic total shoulder arthroplasty versus reverse shoulder arthroplasty at a minimum eight-year follow-up or revision. METHODS: Between 2005 and 2010, 187 shoulders (137 anatomic total shoulder arthroplasty, 50 reverse shoulder arthroplasty) were retrospectively reviewed at a mean of 8.8 years. The mean age at surgery was 67 years. Females were more commonly treated with reverse shoulder arthroplasty. Both groups had similar body mass index and comorbidities. Outcome measures evaluated included abduction, forward elevation, external rotation, internal rotation, Simple Shoulder Test, Constant score, American Shoulder and Elbow Score, University of California Los Angeles Shoulder score, and Shoulder Pain and Disability Index. RESULTS: At follow-up, anatomic total shoulder arthroplasty demonstrated greater overhead range of motion and external rotation. All patient-reported outcomes remained similar between groups. Reverse shoulder arthroplasty patients were more likely to rate shoulders as much better or better after surgery (90% versus 67%, p = 0.004). Complications were observed in 24% of anatomic total shoulder arthroplasties and 8% of reverse shoulder arthroplasties (p = 0.02). Reoperation was more common in anatomic total shoulder arthroplasties (23% versus 4%, p = 0.003). DISCUSSION: At mid-to-long-term follow-up, reverse shoulder arthroplasties demonstrated significantly fewer complications and reoperations than anatomic total shoulder arthroplasties. Despite similar patient-reported outcomes, reverse shoulder arthroplasty patients were more likely to be satisfied with their shoulder.

Validation of a machine learning-derived clinical metric to quantify outcomes after total shoulder arthroplasty.

BACKGROUND: We propose a new clinical assessment tool constructed using machine learning, called the Shoulder Arthroplasty Smart (SAS) score to quantify outcomes following total shoulder arthroplasty (TSA). METHODS: Clinical data from 3667 TSA patients with 8104 postoperative follow-up reports were used to quantify the psychometric properties of validity, responsiveness, and clinical interpretability for the proposed SAS score and each of the Simple Shoulder Test (SST), Constant, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), University of California Los Angeles (UCLA), and Shoulder Pain and Disability Index (SPADI) scores. RESULTS: Convergent construct validity was demonstrated, with all 6 outcome measures being moderately to highly correlated preoperatively and highly correlated postoperatively when quantifying TSA outcomes. The SAS score was most correlated with the UCLA score and least correlated with the SST. No clinical outcome score exhibited significant floor effects preoperatively or postoperatively or significant ceiling effects preoperatively; however, significant ceiling effects occurred postoperatively for each of the SST (44.3%), UCLA (13.9%), ASES (18.7%), and SPADI (19.3%) measures. Ceiling effects were more pronounced for anatomic than reverse TSA, and generally, men, younger patients, and whites who received TSA were more likely to experience a ceiling effect than TSA patients who were female, older, and of non-white race or ethnicity. The SAS score had the least number of patients with floor and ceiling effects and also exhibited no response bias in any patient characteristic analyzed in this study. Regarding clinical interpretability, patient satisfaction anchor-based thresholds for minimal clinically importance difference and substantial clinical benefit were quantified for all 6 outcome measures; the SAS score thresholds were most similar in magnitude to the Constant score. Regarding responsiveness, all 6 outcome measures detected a large effect, with the UCLA exhibiting the most responsiveness and the SST exhibiting the least. Finally, each of the SAS, ASES, Constant, and SPADI scores had similarly large standardized response mean and effect size responsiveness. DISCUSSION: The 6-question SAS score is an efficient TSA-specific outcome measure with equivalent or better validity, responsiveness, and clinical interpretability as 5 other historical assessment tools. The SAS score has an appropriate response range without floor or ceiling effects and without bias in any target patient characteristic, unlike the age, gender, or race/ethnicity bias observed in the ceiling scores with the other outcome measures. Because of these substantial benefits, we recommend the use of the new SAS score for quantifying TSA outcomes.

Osteoarthritis of the shoulder in under-50 year-olds: A multicenter retrospective study of 273 shoulders by the French Society for Shoulder and Elbow (SOFEC).

INTRODUCTION: Osteoarthritis (OA) of the shoulder in under-50 year-olds is rare, and treatment is delicate. Shoulder replacement incurs frequent long-term risk of progression and a high revision rate, making it unsuited to young active patients. The aim of the present study was to determine the epidemiology of shoulder OA in under-50 year-olds and to assess the clinical results of the various treatment options. HYPOTHESIS: The main study hypothesis was that well-conducted non-operative treatment can allow shoulder replacement to be postponed. The secondary hypothesis was that anatomic total shoulder arthroplasty (TSA) is the treatment of choice when other options fail. MATERIALS AND METHODS: A multicenter retrospective study included primary (POA) and post-instability osteoarthritis (PIOA) in patients aged≤50years at symptom onset. Exclusion criteria comprised post-traumatic OA, rheumatoid arthritis and necrosis. Two hundred and sixty-six patients for 273 shoulders were included from 13 shoulder surgery centers: 2 types of non-operative treatment (28 by platelet-rich plasma [PRP] and 88 by viscosupplementation), 73 arthroscopies, and 150 implantations (62 humeral hemiarthroplasties [HA], comprising 10 hemi-metal, 24 hemi-pyrocarbon and 28 hemi-resurfacing; 77 anatomic total prostheses, and 11 reverse prostheses). Minimum follow-up was 12 months for non-operative treatment and 24 months for arthroplasty (some patients having both). Endpoints comprised Constant score, Subjective Shoulder Value (SSV) and number of complications/revision procedures. RESULTS: Mean age at treatment was 43 years (range, 23-65 years), with 75% male predominance. Symptom onset was earlier in PIOA than in POA: 36 vs. 39 years (range, 20-50 years). PRP and viscosupplementation postponed implantation by a mean 3.5 years in 86% of cases, as did arthroscopy in 56%. ER1 restriction was the most negative factor. At 74 months' follow-up for HA and 95 months for TSA, mean Constant score was significantly lower for HA (56 vs. 67; p=0.004), with higher rates of complications (31% vs. 11%) and implant exchange (13% vs. 9%). DISCUSSION/CONCLUSION: PRP, viscosupplementation and arthroscopy allow implantation to be postponed until the shoulder becomes stiff and painful. In case of failure, TSA is the most effective solution in the medium-term. LEVEL OF EVIDENCE: IV a; therapeutic study - investigating the results of treatment.

Using machine learning to predict clinical outcomes after shoulder arthroplasty with a minimal feature set.

BACKGROUND: A machine learning analysis was conducted on 5774 shoulder arthroplasty patients to create predictive models for multiple clinical outcome measures after anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA). The goal of this study was to compare the accuracy associated with a full-feature set predictive model (ie, full model, comprising 291 parameters) and a minimal-feature set model (ie, abbreviated model, comprising 19 input parameters) to predict clinical outcomes to assess the efficacy of using a minimal feature set of inputs as a shoulder arthroplasty clinical decision-support tool. METHODS: Clinical data from 2153 primary aTSA patients and 3621 primary rTSA patients were analyzed using the XGBoost machine learning technique to create and test predictive models for multiple outcome measures at different postoperative time points via the full and abbreviated models. Mean absolute errors (MAEs) quantified the difference between actual and predicted outcomes, and each model also predicted whether a patient would experience clinical improvement greater than the patient satisfaction anchor-based thresholds of the minimal clinically important difference and substantial clinical benefit for each outcome measure at 2-3 years after surgery. RESULTS: Across all postoperative time points analyzed, the full and abbreviated models had similar MAEs for the American Shoulder and Elbow Surgeons score (±11.7 with full model vs. ±12.0 with abbreviated model), Constant score (±8.9 vs. ±9.8), Global Shoulder Function score (±1.4 vs. ±1.5), visual analog scale pain score (±1.3 vs. ±1.4), active abduction (±20.4° vs. ±21.8°), forward elevation (±17.6° vs. ±19.2°), and external rotation (±12.2° vs. ±12.6°). Marginal improvements in MAEs were observed for each outcome measure prediction when the abbreviated model was supplemented with data on implant size and/or type and measurements of native glenoid anatomy. The full and abbreviated models each effectively risk stratified patients using only preoperative data by accurately identifying patients with improvement greater than the minimal clinically important difference and substantial clinical benefit thresholds. DISCUSSION: Our study showed that the full and abbreviated machine learning models achieved similar accuracy in predicting clinical outcomes after aTSA and rTSA at multiple postoperative time points. These promising results demonstrate an efficient utilization of machine learning algorithms to predict clinical outcomes. Our findings using a minimal feature set of only 19 preoperative inputs suggest that this tool may be easily used during a surgical consultation to improve decision making related to shoulder arthroplasty.

Comparison of complication types and rates associated with anatomic and reverse total shoulder arthroplasty.

BACKGROUND: Complications after anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty can be devastating to a patient's quality of life and require revisions that are costly to both the patient and the health care system. The purpose of this study is to determine the types, incidence, and timing of complications following aTSA and rTSA using an international database of patients who received a single-platform total shoulder arthroplasty system, in order to quantify the types of failure modes and the differences that occur between aTSA and rTSA. METHODS: A total of 2224 aTSA (male-female, 1090:1134) and 4158 rTSA (male-female, 1478:2680) patients were enrolled in an international database of primary shoulder arthroplasty performed by 40 different surgeons in the United States and Europe. Adverse events and revisions reported for these 6382 patients were analyzed to identify the most common failure modes associated for both aTSA and rTSA. RESULTS: For the 2224 aTSA patients, 239 adverse events were reported for a complication rate of 10.7% and 124 revisions for a revision rate of 5.6%. The top 3 complications for aTSA were rotator cuff tear/subscapularis failure (n = 69; complication rate = 3.1%, revision rate = 1.9%), aseptic glenoid loosening (n = 55; complication rate = 2.5%, revision rate = 1.9%), and infection (n = 28; complication rate = 1.3%, revision rate = 0.8%). For the 4158 rTSA patients, 372 adverse events were reported for a complication rate of 8.9% and 104 revisions for a revision rate of 2.5%. The top 3 complications for rTSA were acromial/scapular fracture/pain (n = 102; complication rate = 2.5%, revision rate = 0.0%), instability (n = 60; complication rate = 1.4%, revision rate = 1.0%), and pain (n = 49; complication rate = 1.2%, revision rate = 0.2%). CONCLUSIONS: This large database analysis quantified complication and revision rates for aTSA and rTSA. We found aTSA and rTSA complication rates of 10.7% and 8.9%, respectively; with revision surgery rates of 5.6% and 2.5%, respectively. The 2 most common complications for each prosthesis type (aTSA: subscapularis/rotator cuff tears, aseptic glenoid loosening; rTSA: acromial/scapular fractures, instability) were unique to each device. The rate of infection was similar for both. Future prosthesis and technique development should work to mitigate these common complication types in order to reduce their rate of occurrence.