Predictors of dislocations after reverse shoulder arthroplasty: a study by the ASES complications of RSA multicenter research group.

BACKGROUND: Instability after reverse shoulder arthroplasty (RSA) is one of the most frequent complications and remains a clinical challenge. Current evidence is limited by small sample size, single-center, or single-implant methodologies that limit generalizability. We sought to determine the incidence and patient-related risk factors for dislocation after RSA, using a large, multicenter cohort with varying implants. METHODS: A retrospective, multicenter study was performed involving 15 institutions and 24 American Shoulder and Elbow Surgeons members across the United States. Inclusion criteria consisted of patients undergoing primary or revision RSA between January 2013 and June 2019 with minimum 3-month follow-up. All definitions, inclusion criteria, and collected variables were determined using the Delphi method, an iterative survey process involving all primary investigators requiring at least 75% consensus to be considered a final component of the methodology for each study element. Dislocations were defined as complete loss of articulation between the humeral component and the glenosphere and required radiographic confirmation. Binary logistic regression was performed to determine patient predictors of postoperative dislocation after RSA. RESULTS: We identified 6621 patients who met inclusion criteria with a mean follow-up of 19.4 months (range: 3-84 months). The study population was 40% male with an average age of 71.0 years (range: 23-101 years). The rate of dislocation was 2.1% (n = 138) for the whole cohort, 1.6% (n = 99) for primary RSAs, and 6.5% (n = 39) for revision RSAs (P < .001). Dislocations occurred at a median of 7.0 weeks (interquartile range: 3.0-36.0 weeks) after surgery with 23.0% (n = 32) after a trauma. Patients with a primary diagnosis of glenohumeral osteoarthritis with an intact rotator cuff had an overall lower rate of dislocation than patients with other diagnoses (0.8% vs. 2.5%; P < .001). Patient-related factors independently predictive of dislocation, in order of the magnitude of effect, were a history of postoperative subluxations before radiographically confirmed dislocation (odds ratio [OR]: 19.52, P < .001), primary diagnosis of fracture nonunion (OR: 6.53, P < .001), revision arthroplasty (OR: 5.61, P < .001), primary diagnosis of rotator cuff disease (OR: 2.64, P < .001), male sex (OR: 2.21, P < .001), and no subscapularis repair at surgery (OR: 1.95, P = .001). CONCLUSION: The strongest patient-related factors associated with dislocation were a history of postoperative subluxations and having a primary diagnosis of fracture nonunion. Notably, RSAs for osteoarthritis showed lower rates of dislocations than RSAs for rotator cuff disease. These data can be used to optimize patient counseling before RSA, particularly in male patients undergoing revision RSA.

Time-Driven Activity-Based Costing Analysis Identifies Use of Consumables and Operating Room Time as Factors Associated With Increased Cost of Outpatient Primary Hip Arthroscopic Labral Repair.

PURPOSE: To use time-driven, activity-based costing (TDABC) methodology to 1) investigate drivers of cost variation and 2) elucidate preoperative and intraoperative factors associated with increased cost of outpatient arthroscopic hip labral repair. METHODS: A retrospective analysis of data from January 2020 to October 2021 was performed. Patients undergoing primary hip arthroscopy for labral repair in the outpatient setting were included. Indexed TDABC data from avant-garde health's analytics platform were used to represent cost-of-care breakdowns. Patients in the top decile of cost were defined as high cost, and cost category variance was determined as a percent increase between high and low cost. Analyses tested for associations between preoperative and perioperative factors with total cost. Surgical procedures performed concomitantly to labral repair were included in subanalyses. RESULTS: Data from 151 patients were analyzed. Consumables made up 61% of total outpatient cost with surgical personnel costs (30%) being the second largest category. The average total cost was 19% higher for patients in the top decile of cost compared to the remainder of the cohort. Factors contributing to this difference were implants (36% higher), surgical personnel (20% higher), and operating room (OR) consumables (15% higher). Multivariate linear regression modeling indicated that OR time (Standardized ß = 0.504; P < .001) and anchor quantity (standardized ß = 0.443; P < .001) were significant predictors of increased cost. Femoroplasty (Unstandardized ß = 15.274; P = .010), chondroplasty (Unstandardized ß = 8.860; P = .009), excision of os acetabuli (unstandardized ß = 13.619; P = .041), and trochanteric bursectomy (Unstandardized ß = 21.176; P = .009) were also all independently associated with increasing operating time. CONCLUSION: TDABC analysis showed that OR consumables and implants were the largest drivers of cost for the procedure. OR time was also shown to be a significant predictor of increased costs. LEVEL OF EVIDENCE: Level IV, economic analysis.

Risk factors of acromial and scapular spine stress fractures differ by indication: a study by the ASES Complications of Reverse Shoulder Arthroplasty Multicenter Research Group.

BACKGROUND: Both patient and implant related variables have been implicated in the incidence of acromial (ASF) and scapular spine fractures (SSF) following reverse shoulder arthroplasty (RSA); however, previous studies have not characterized nor differentiated risk profiles for varying indications including primary glenohumeral arthritis with intact rotator cuff (GHOA), rotator cuff arthropathy (CTA), and massive irreparable rotator cuff tear (MCT). The purpose of this study was to determine patient factors predictive of cumulative ASF/SSF risk for varying preoperative diagnosis and rotator cuff status. METHODS: Patients consecutively receiving RSA between January 2013 and June 2019 from 15 institutions comprising 24 members of the American Shoulder and Elbow Surgeons (ASES) with primary, preoperative diagnoses of GHOA, CTA and MCT were included for study. Inclusion criteria, definitions, and inclusion of patient factors in a multivariate model to predict cumulative risk of ASF/SSF were determined through an iterative Delphi process. The CTA and MCT groups were combined for analysis. Consensus was defined as greater than 75% agreement amongst contributors. Only ASF/SSF confirmed by clinical and radiographic correlation were included for analysis. RESULTS: Our study cohort included 4764 patients with preoperative diagnoses of GHOA, CTA, or MCT with minimum follow-up of 3 months (range: 3-84). The incidence of cumulative stress fracture was 4.1% (n = 196). The incidence of stress fracture in the GHOA cohort was 2.1% (n = 34/1637) compared to 5.2% (n = 162/3127) (P < .001) in the CTA/MCT cohort. Presence of inflammatory arthritis (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.08-7.78; P = .035) was the sole predictive factor of stress fractures in GHOA, compared with inflammatory arthritis (OR 1.86, 95% CI 1.19-2.89; P = .016), female sex (OR 1.81, 95% CI 1.20-2.72; P = .007), and osteoporosis (OR 1.56, 95% CI 1.02-2.37; P = .003) in the CTA/MCT cohort. CONCLUSION: Preoperative diagnosis of GHOA has a different risk profile for developing stress fractures after RSA than patients with CTA/MCT. Though rotator cuff integrity is likely protective against ASF/SSF, approximately 1/46 patients receiving RSA with primary GHOA will have this complication, primarily influenced by a history of inflammatory arthritis. Understanding risk profiles of patients undergoing RSA by varying diagnosis is important in counseling, expectation management, and treatment by surgeons.

Do Outcomes Differ After Proximal Hamstring Repair for Patients Receiving Workers' Compensation?

Background: Patients with workers' compensation (WC) insurance claims are often shown to experience inferior patient-reported outcomes (PROs) after an orthopaedic surgical intervention compared with patients without WC claims. Purpose: To compare the postoperative PROs of patients with WC claims (WC patients) versus those without WC claims (non-WC patients) after proximal hamstring repair (PHR). Study Design: Cohort study; Level of evidence, 3. Methods: WC patients who underwent PHR between November 2011 and to September 2020 were propensity score matched at a 1:2 ratio to non-WC patients according to age, sex, and body mass index. Comorbidity data were collected as well as minimum 1-year postoperative PRO scores for the Lower Extremity Functional Scale (LEFS), the Hip Outcome Score (HOS), and the 12-Item Short From Health Survey (SF-12) Physical Component Summary (PCS) and Mental Component Summary (MCS). The type of work was characterized according to national WC insurance guidelines as light (maximum 20 lbs [9.1 kg]), medium (maximum 50 lbs [22.7 kg]), or heavy (≥50 lbs) [>/=22.7 kg]. Results: A total of 30 patients (10 WC and 20 non-WC) were included. The work type and baseline demographic characteristics of patients did not differ between groups. There were no significant between-group differences in postoperative PRO scores as measured by the LEFS (P = .488), HOS (P = .233), or SF-12 PCS (P = .521). However, the WC cohort showed inferior SF-12 MCS scores compared with the non-WC group (49.28 ± 9.97 vs 54.26 ± 9.69, respectively; P = .032). The WC status was also associated with an increased time needed for patients to return to full-duty work capacity (21 ± 9 vs 9 ± 8 weeks; P = .005). Conclusion: Our findings suggest that WC and non-WC patients who undergo PHR have comparable outcomes. Differences in SF-12 MCS scores and return to work time for full-duty capacity warrant further investigation.

Reassessing the minimum two-year follow-up standard after total shoulder arthroplasty-Is one year sufficient?

BACKGROUND: US Food and Drug Administration Investigation Device Exemption studies and academic journals emphasize the importance of two-year follow-up data in reporting outcomes of total shoulder arthroplasty, but there is limited data evaluating appropriate follow-up length. We aim to evaluate change in postoperative outcomes and complications between one and two years following anatomic and reverse total shoulder arthroplasties. METHODS: We retrospectively identified 250 patients who underwent anatomic and reverse total shoulder arthroplasties between 2013 and 2016 from a single surgeon arthroplasty registry. Patients without both one- and two-year follow-up data were excluded. We compared American Shoulder and Elbow Surgeons (ASES) score, Visual Analog Scale for pain, and goniometer-measured range of motion. RESULTS: Patient-reported outcome measurements (p > 0.05) did not change between one and two years postoperatively following both reverse (n = 146) and anatomic (n = 104) total shoulder arthroplasties. Range of motion increased slightly (p < 0.05), but this change was not clinically relevant. There were no additional complications. DISCUSSION: Minimum two-year clinical follow-up may not be necessary for future shoulder arthroplasty Investigation Device Exemption and other peer-reviewed investigations. Patient-reported outcomes (ASES and pain score) and range of motion plateau at one year postoperatively without additional complications. One-year follow-up is an acceptable minimum follow-up length. LEVEL OF EVIDENCE: Level III-retrospective analysis.

Predictors of acromial and scapular stress fracture after reverse shoulder arthroplasty: a study by the ASES Complications of RSA Multicenter Research Group.

BACKGROUND: Acromial (ASF) and scapular spine (SSF) stress fractures are well-recognized complications of reverse shoulder arthroplasty (RSA), but much of the current data are derived from single-center or single-implant studies with limited generalizability. This study from the American Shoulder and Elbow Surgeons (ASES) Complications of Reverse Shoulder Arthroplasty Multicenter Research Group determined the incidence of ASF/SSF after RSA and identified preoperative patient characteristics associated with their occurrence. METHOD: Fifteen institutions including 21 ASES members across the United States participated in this study. Patients undergoing either primary or revision RSA between January 2013 and June 2019 with a minimum 3-month follow-up were included. All definitions and inclusion criteria were determined using the Delphi method, an iterative survey process involving all primary investigators. Consensus was achieved when at least 75% of investigators agreed on each aspect of the study protocol. Only symptomatic ASF/SSF diagnosed by radiograph or computed tomography were considered. Multivariable logistic regression was performed to identify factors associated with ASF/SSF development. RESULTS: We identified 6755 RSAs with an average follow-up of 19.8 months (range, 3-94). The total stress fracture incidence rate was 3.9% (n = 264), of which 3.0% (n = 200) were ASF and 0.9% (n = 64) were SSF. Fractures occurred at an average 8.2 months (0-64) following RSA with 21.2% (n = 56) following a trauma. Patient-related factors independently predictive of ASF were chronic dislocation (odds ratio [OR] 3.67, P = .04), massive rotator cuff tear without arthritis (OR 2.51, P < .01), rotator cuff arthropathy (OR 2.14, P < .01), self-reported osteoporosis (OR 2.21, P < .01), inflammatory arthritis (OR 2.18, P < .01), female sex (OR 1.51, P = .02), and older age (OR 1.02 per 1-year increase, P = .02). Factors independently associated with the development of SSF included osteoporosis (OR 2.63, P < .01), female sex (OR 2.34, P = .01), rotator cuff arthropathy (OR 2.12, P = .03), and inflammatory arthritis (OR 2.05, P = .03). CONCLUSION: About 1 in 26 patients undergoing RSA will develop a symptomatic ASF or SSF, more frequently within the first year of surgery. Our results indicate that severe rotator cuff disease may play an important role in the occurrence of stress fractures following RSA. This information can be used to counsel patients about potential setbacks in recovery, especially among older women with suboptimal bone health. Strategies for prevention of ASF and SSF in these at-risk patients warrant further study. A follow-up study evaluating the impact of prosthetic factors on the incidence rates of ASF and SSF may prove highly valuable in the decision-making process.

Reassessing glenoid inclination in reverse total shoulder arthroplasty with glenosphere lateralization.

AIMS: Existing literature indicates that inferiorly inclined glenoid baseplates following reverse total shoulder arthroplasty (RSA) produce better outcomes compared to superiorly inclined baseplates. We aim to compare clinical outcomes for RSAs with superiorly and neutrally/inferiorly inclined lateralized glenospheres. METHODS: We retrospectively reviewed 154 consecutive patients undergoing RSA between July 2015 and July 2017 by one single-fellowship trained surgeon (AJ). Two raters (KAM and MVS) independently measured glenoid inclination in preoperative and minimum two year follow-up radiographs (anteroposterior/Grashey) using the RSA angle. Inclination was then compared to patient-reported outcomes, range of motion (ROM), and independently assessed degree of scapular notching and staging of heterotopic ossification at two year follow-up. RESULTS: Median postoperative inclination for each group was found to be -3.6° (interquartile range (IQR) -2.1 to -6.9) and 6.0° (3.2° to 10.1°) for the neutrally/inferiorly and superiorly inclined cohorts, respectively. Preoperative inclination was highly associated with postoperative inclination (p = 0.004). When comparing superiorly and neutrally/inferiorly inclined glenospheres, there were no differences in heterotopic ossification (p = 0.606), scapular notching (p = 0.367), American Shoulder and Elbow Surgeons score (p = 0.419), Single Assessment Numeric Evaluation (p = 0.417), Visual Analogue Scale (VAS) pain score (p = 0.290), forward elevation (p = 0.161), external rotation (p = 0.537), or internal rotation (p = 0.656). CONCLUSION: Compared to neutral and inferior inclination, up to 6° ± 3° of superior glenoid baseplate inclination on a lateralized RSA design produces no differences in postoperative ROM or patient-reported outcomes, and produces similar levels of scapular notching and heterotopic ossification. Additionally, the degree of preoperative inclination represents an important factor in surgical decision-making as it is strongly associated with postoperative inclination. It is important to note that the findings of this study are only reflective of lateralized RSA prostheses. Cite this article: Bone Joint J 2021;103-B(2):360-365.

Identifying surgeon and institutional drivers of cost in total shoulder arthroplasty: a multicenter study.

BACKGROUND: Despite rapid increases in the demand for total shoulder arthroplasty, data describing cost trends are scarce. We aim to (1) describe variation in the cost of shoulder arthroplasty performed by different surgeons at multiple hospitals and (2) determine the driving factors of such variation. METHODS: A standardized, highly accurate cost accounting method, time-driven activity-based costing, was used to determine the cost of 1571 shoulder arthroplasties performed by 12 surgeons at 4 high-volume institutions between 2016 and 2018. Costs were broken down into supply costs (including implant price and consumables) and personnel costs, including physician fees. Cost parameters were compared with total cost for surgical episodes and case volume. RESULTS: Across 4 institutions and 12 surgeons, surgeon volume and hospital volume did not correlate with episode-of-care cost. Average cost per case of each institution varied by factors of 1.6 (P = .47) and 1.7 (P = .06) for anatomic total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RSA), respectively. Implant (56% and 62%, respectively) and personnel costs from check-in through the operating room (21% and 17%, respectively) represented the highest percentages of cost and highly correlated with the cost of the episode of care for TSA and RSA. CONCLUSIONS: Variation in episode-of-care total costs for both TSA and RSA had no association with hospital or surgeon case volume at 4 high-volume institutions but was driven primarily by variation in implant and personnel costs through the operating room. This analysis does not address medium- or long-term costs.

Patient risk factors for acromial stress fractures after reverse shoulder arthroplasty: a multicenter study.

BACKGROUND: Despite the growing recognition of acromial stress fractures (ASFs) after reverse total shoulder arthroplasty (RTSA), most of the current data are derived from single-center studies with limited generalizability. This multicenter study investigated the incidence of ASFs after RTSA and identified preoperative patient characteristics associated with their occurrence. METHODS: Using 2 institutional registries from different regions of the United States, we identified 1479 patients undergoing either primary or revision RTSA between 2013 and 2018 with minimum 3-month follow-up. ASFs were defined as radiographic evidence of an acromial or scapular spine fracture with clinical symptoms (eg, tenderness over the acromion or scapular spine). Multivariable logistic regression was performed to identify preoperative patient factors associated with the development of ASFs. RESULTS: Overall, 54 (3.7%) patients were diagnosed with an ASF after RTSA. Patient-related factors independently associated with the development of an ASF included female sex (odds ratio [OR], 2.21 reference: male; 95% confidence interval [CI], 1.03-4.74; P < .05), rheumatoid arthritis (OR, 2.30; 95% CI, 1.02-5.16; P < .05), osteoporosis (OR, 2.55; 95% CI, 1.24-5.21; P < .05), a diagnosis of degenerative joint disease with rotator cuff tear (OR, 4.74 reference: degenerative joint disease without rotator cuff tear; 95% CI, 1.84-12.23; P < .05), and fracture malunion/nonunion (OR, 5.21; 95% CI, 1.20-22.76; P < .05). CONCLUSIONS: The non-negligible percentage of ASFs that occur after RTSA is associated with the diagnoses of rotator cuff dysfunction and chronic fracture sequelae in female patients with suboptimal bone health. This information can be used to counsel patients and set expectations about potential setbacks in recovery.

Variation in the value of total shoulder arthroplasty.

BACKGROUND: There is growing interest in maximizing value for patients undergoing discretionary orthopedic surgery but little data to guide improvement efforts. Integrating patient-reported outcomes with time-driven activity-based costing, we explored patient-level variation in the value of total shoulder arthroplasty (TSA) and characterized factors that contribute to this variation. METHODS: Using our institutional registry, we identified 239 patients undergoing elective primary TSA (anatomic or reverse) between 2016-2017 with minimum 2-year follow-up. We calculated value as 2-year postoperative American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores divided by hospitalization time-driven activity-based costs. This number was multiplied by a constant to set the minimum value of TSA to 100. Multivariable linear regression modeling was performed to characterize factors underlying variation in value. RESULTS: The value of shoulder arthroplasty ranged from 100 to 680, resulting in a variation of 580%. Reverse shoulder arthroplasty was associated with decreased value (79-point decrease vs. anatomic arthroplasty; P < .001; partial R2 = 0.089), as were prior ipsilateral shoulder surgery (38-point decrease; P = .002; partial R2 = 0.031), more self-reported allergies (4-point decrease per 1-unit increase; P = .029; partial R2 = 0.015), diabetes (33-point decrease; P = .045; partial R2 = 0.013), and lower preoperative ASES score (0.7-point increase per 1-unit increase; P = .045; partial R2 = 0.012). CONCLUSIONS: We observed wide variation in the value of shoulder arthroplasty that was most strongly associated with procedure type and certain preoperative characteristics (eg, prior shoulder surgery, number of self-reported allergies, diabetes, ASES score). Awareness of these associations is important for implementation of targeted strategies to effectively reduce variation and redirect resources toward higher-value, cost-conscious care.

Lateralization and Decreased Neck-Shaft Angle Reduces Scapular Notching and Heterotopic Ossification.

BACKGROUND: Lateralization of the glenosphere in reverse shoulder arthroplasty likely mitigates scapular notching; however, there is a paucity of data evaluating the effect of heterotopic ossification (HO) at the inferior aspect of the glenoid neck. METHODS: We retrospectively reviewed 107 consecutive reverse shoulder arthroplasty patients between April 2013 and April 2016. During the study period, the surgeon switched from a 2.5-mm lateral center of rotation and a 155° neck-shaft angle (NSA) to a 6- or 10-mm lateralized design with a 135° NSA. Preoperative and minimum 2-year postoperative patient-reported outcomes and range of motion were collected. Two-year postoperative radiographs were evaluated for scapular notching and HO. RESULTS: The lateralized center of rotation implant was 72% less likely to develop HO and 85% less likely to produce scapular notching than the medialized prosthesis. CONCLUSION: Implants with laterally offset glenospheres and 135° NSA may decrease postoperative HO and scapular notching. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Variation in the Cost of Care for Different Types of Joint Arthroplasty.

BACKGROUND: Lower-extremity arthroplasty constitutes the largest burden on health-care spending of any Medicare diagnosis group. Demand for upper extremity arthroplasty also continues to rise. It is necessary to better understand costs as health care shifts toward a bundled-payment accounting approach. We aimed (1) to identify whether variation exists in total cost for different types of joint arthroplasty, and, if so, (2) to determine which cost parameters drive this variation. METHODS: The cost of the episode of inpatient care for 22,215 total joint arthroplasties was calculated by implementing time-driven activity-based costing (TDABC) at a single orthopaedic specialty hospital from 2015 to 2018. Implant price, supply costs, personnel costs, and length of stay for total knee, total hip, anatomic total shoulder, reverse total shoulder, total elbow, and total ankle arthroplasty were analyzed. Individual cost parameters were compared with total cost and volume. RESULTS: Higher implant cost appeared to correlate with higher total costs and represented 53.8% of the total cost for an inpatient care cycle. Total knee arthroplasty was the least-expensive and highest-volume procedure, whereas total elbow arthroplasty had the lowest volume and highest cost (1.65 times more than that of total knee arthroplasty). Length of stay was correlated with increased personnel cost but did not have a significant effect on total cost. CONCLUSIONS: Total inpatient cost at our orthopaedic specialty hospital varied by up to a factor of 1.65 between different fields of arthroplasty. The highest-volume procedures-total knee and hip arthroplasty-were the least expensive, driven predominantly by lower implant purchase prices. CLINICAL RELEVANCE: We are not aware of any previous studies that have accurately compared cost structures across upper and lower-extremity arthroplasty with a uniform methodology. The present study, because of its uniform accounting process, provides reliable data that will allow clinicians to better understand cost relationships between different procedures.

Delayed hospital discharge after total shoulder arthroplasty: why, and who is at risk?

BACKGROUND: There is growing policy interest in reducing the length of stay (LOS) after discretionary orthopedic surgery but few data to guide improvement efforts. We characterized the primary reasons and predisposing factors associated with extended LOS after elective total shoulder arthroplasty. METHODS: We retrospectively identified 415 patients undergoing elective primary total shoulder arthroplasty between 2016 and 2017. Extended LOS was defined as a stay greater than the 75th percentile. Medical records were manually reviewed to ascertain the primary reason for extended LOS. Multivariable logistic regression modeling was used to determine preoperative characteristics associated with prolonged hospitalization. RESULTS: The most common reason for extended LOS was pain (41%), followed by medical problems (39%), limited social support (18%), and blood transfusions (2%). Only 41% of patients with delayed discharges had documented adverse events (any medical or surgical problem), all of which were minor. The top 4 medical issues were transient hypoxemia (42%), nausea and/or vomiting (13%), electrolyte abnormalities (12%), and altered mental status (10%). In decreasing order of magnitude, the predictors of prolonged LOS were greater number of self-reported allergies, female sex, unmarried patient, diabetes, lower American Shoulder and Elbow Surgeons score, depression, reverse shoulder arthroplasty, and American Society of Anesthesiologists score of 3 or greater. Operative time did not correlate with LOS. CONCLUSIONS: Prolonged hospitalizations after shoulder arthroplasty are commonly related to pain and limited social support. Sociodemographic and psychological factors seem to have more influence than patient infirmity and technical issues. These findings support a comprehensive approach to care with attention to the physical, mental, and social determinants of health.