Quantifying success after first revision reverse total shoulder arthroplasty: the minimal and substantial clinically important percentage of maximal possible improvement.

BACKGROUND: When patients require reoperation after primary shoulder arthroplasty, revision reverse total shoulder arthroplasty (rTSA) is most commonly performed. However, defining clinically important improvement in these patients is challenging because benchmarks have not been previously defined. Furthermore, although the minimal clinically important difference and substantial clinical benefit are commonly used to assess clinically relevant success, these metrics are limited by ceiling effects that may cause inaccurate estimates of patient success. Our purpose was to define the minimal and substantial clinically important percentage of maximal possible improvement (MCI-%MPI and SCI-%MPI) for commonly used pain and functional outcome scores after revision rTSA and to quantify the proportion of patients achieving clinically relevant success. METHODS: This retrospective cohort study used a prospectively collected single-institution database of patients who underwent first revision rTSA between August 2015 and December 2019. Patients with a diagnosis of periprosthetic fracture or infection were excluded. Outcome scores included the American Shoulder and Elbow Surgeons (ASES), raw and normalized Constant, Shoulder Pain and Disability Index (SPADI), Simple Shoulder Test (SST), and University of California, Los Angeles (UCLA) scores. We used an anchor-based method to calculate the MCI-%MPI and SCI-%MPI. In addition, we calculated the MCI-%MPI using a distribution-based method for historical comparison. The proportions of patients achieving each threshold were assessed. The influence of sex, type of primary shoulder arthroplasty, and reason for revision rTSA were also assessed by calculating cohort-specific thresholds. RESULTS: Ninety-three revision rTSAs with minimum 2-year follow-up were evaluated. The mean age of the patients was 67 years; 56% were female, and the average follow-up was 54 months. Revision rTSA was performed most commonly for failed anatomic TSA (n = 47), followed by hemiarthroplasty (n = 21), rTSA (n = 15), and humeral head resurfacing (n = 10). The indication for revision rTSA was most commonly glenoid loosening (n = 24), followed by rotator cuff failure (n = 23) and subluxation and unexplained pain (n = 11 for both). The anchor-based MCI-%MPI thresholds (% of patients achieving) were ASES = 33% (49%), raw Constant = 23% (64%), normalized Constant = 30% (61%), UCLA = 51% (53%), SST = 26% (68%), and SPADI = 29% (58%). The anchor-based SCI-%MPI thresholds (% of patients achieving) were ASES = 55% (31%), raw Constant = 41% (27%), normalized Constant = 52% (22%), UCLA = 66% (37%), SST = 74% (25%), and SPADI = 49% (34%). CONCLUSIONS: This study is the first to establish thresholds for the MCI-%MPI and SCI-%MPI at minimum 2 years after revision rTSA, providing physicians an evidence-based method to assess patient outcomes postoperatively.

Does achieving clinically important thresholds after first shoulder arthroplasty predict similar outcomes of the contralateral shoulder?

BACKGROUND: Patients are increasingly undergoing bilateral total shoulder arthroplasty (TSA). At present, it is unknown whether success after the first TSA is predictive of success after contralateral TSA. We aimed to determine whether exceeding clinically important thresholds of success after primary TSA predicts similar outcomes for subsequent contralateral TSA. METHODS: We performed a retrospective review of a prospectively collected shoulder arthroplasty database for patients undergoing bilateral primary anatomic (aTSA) or reverse (rTSA) total shoulder arthroplasty since January 2000 with preoperative and 2- or 3-year clinical follow-up. Our primary outcome was whether exceeding clinically important thresholds in the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score for the first TSA was predictive of similar success of the contralateral TSA; thresholds for the ASES score were adopted from prior literature and included the minimal clinically important difference (MCID), the substantial clinical benefit (SCB), 30% of maximal possible improvement (MPI), and the patient acceptable symptomatic state (PASS). The PASS is defined as the highest level of symptom beyond which patients consider themselves well, which may be a better indicator of a patient's quality of life. To determine whether exceeding clinically important thresholds was independently predictive of similar success after second contralateral TSA, we performed multivariable logistic regression adjusted for age at second surgery, sex, BMI, and type of first and second TSA. RESULTS: Of the 134 patients identified that underwent bilateral shoulder arthroplasty, 65 (49%) had bilateral rTSAs, 45 (34%) had bilateral aTSAs, 21 (16%) underwent aTSA/rTSA, and 3 (2%) underwent rTSA/aTSA. On multivariable logistic regression, exceeding clinically important thresholds after first TSA was not associated with greater odds of achieving thresholds after second TSA when success was evaluated by the MCID, SCB, and 30% MPI. In contrast, exceeding the PASS after first TSA was associated with 5.9 times greater odds (95% confidence interval 2.5-14.4, P < .001) of exceeding the PASS after second TSA. Overall, patients who exceeded the PASS after first TSA exceeded the PASS after second TSA at a higher rate (71% vs. 29%, P < .001); this difference persisted when stratified by type of prosthesis for first and second TSA. CONCLUSIONS: Patients who achieve the ASES score PASS after first TSA have greater odds of achieving the PASS for the contralateral shoulder regardless of prostheses type.

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.

Early outcomes after first reverse total shoulder arthroplasty better prognosticate contralateral success compared with early outcomes after anatomic total shoulder arthroplasty.

BACKGROUND: The ideal timing between bilateral total shoulder arthroplasty (TSA) is unclear. The purpose of this study is to determine whether early outcomes after first TSA can be used to predict clinical outcomes after TSA of the contralateral shoulder and to evaluate the ideal time after TSA to perform the contralateral shoulder. METHODS: A single-institution prospectively collected shoulder arthroplasty database was reviewed. Patients who underwent bilateral primary anatomic or reverse TSA (aTSA + rTSA) without an indication of fracture, tumor, or infection were identified. Included patients had minimum 2-year follow-up on their second TSA and postoperative follow-up after their first TSA at 3 months, 6 months, 1 year, or 2 years. Our primary outcome was whether outcome scores and motion at 3-month, 6-month, 1-year, and 2-year follow-up after first TSA predicted clinical success after second TSA at final follow-up, defined as achieving the patient acceptable symptomatic state (PASS = the highest level of symptoms beyond which patients consider themselves well). Outcomes included the American Shoulder and Elbow Surgeons and Constant scores, abduction, forward elevation, and external/internal-rotation. Multivariable logistic regression determined whether postoperative outcomes after first TSA were predictive of achieving the PASS after second TSA independent of age, sex, and body mass index. Receiver operating characteristic analysis determined cutoffs of postoperative outcomes after first TSA at each time point that best predicted achieving the prosthesis-specific PASS after second TSA. RESULTS: One hundred thirty-four patients were included in the final analysis (110 aTSA and 158 rTSA). Range of motion and outcome scores at late (1- or 2-year) follow-up after first aTSA were more predictive of achieving the second TSA PASS compared with early (3- or 6-month) outcomes. In contrast, outcomes after early and late follow-up after first rTSA were similarly predictive of achieving the second TSA PASS. Specifically, the Constant score threshold at 2 years after first aTSA (79.4; area under the curve [AUC] = 0.804) better differentiated achieving the second TSA PASS vs. the 6-month threshold (72.0; AUC = 0.600). In contrast, the Constant score threshold at 2 years after first rTSA (76.4; AUC = 0.703) was similarly discriminant of achieving the second TSA PASS compared with the 6-month threshold (65.8; AUC = 0.711). CONCLUSIONS: Patients with good outcomes after first rTSA can be counseled on contralateral TSA as early as 3 months postoperatively with confidence of a similar result on the contralateral side. In contrast, success after first aTSA does not reliably predict contralateral success until ≥1 year.

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.

Survivorship after reverse total shoulder arthroplasty and predictors of 1-year and overall mortality.

BACKGROUND: Patient survivorship and risk factors of mortality after reverse total shoulder arthroplasty (RTSA) are seldom and inadequately studied. The purpose of this study was to evaluate the mortality rates and predictors of 1-year and overall mortality after RTSA. METHODS: We retrospectively reviewed 1518 consecutive adult patients who underwent RTSA at our institution. The Social Security Death Index and institutional electronic medical records were queried to verify patient living status. Patients were censored at date of death if deceased, the date that living status was verified if alive, or latest follow-up if living status could not be verified. Mortality rates and risk factors of 1-year and overall mortality after RTSA were identified on univariate and multivariate analysis. RESULTS: Mean follow-up was 5.1 ± 3.8 years. Thirty-day (0.1%), 90-day (0.7%), and 1-year (1.8%) mortality rates were low but increased to 11% at 5 years. Increased odds of 1-year mortality were independently associated with heart disease (odds ratio [OR] 2.64, 95% confidence interval [CI] 1.07-6.50, P = .035) and use of a cemented stem (OR 2.64, 95% CI 1.04-6.69, P = .041). Independent risk factors of overall mortality included older age at surgery (hazard ratio [HR] 1.05, 95% CI 1.03-1.07, P < .001), minority ethnicity (protective risk factor, HR 0.37, 95% CI 0.15-0.91, P = .031), heart disease (HR 1.42, 95% CI 1.00-2.02, P = .048), diabetes mellitus (HR 1.47, 95% CI 1.04-2.08, P = .028), tobacco use (HR 1.79, 95% CI 1.08-2.98, P = .025), post renal transplant (HR 12.69, 95% CI 3.92-41.05, P < .001), chronic liver failure (HR 4.40, 95% CI 1.38-14.09, P = .013), and receiving a cemented stem (HR 1.60, 95% CI 1.13-2.26, P = .008). CONCLUSIONS: RTSA carries a low risk of short-term mortality postoperatively. When counseling patients preoperatively, surgeons should consider the predictors of mortality after RTSA reported herein to ensure appropriate patient selection and counseling.

Congenital Mastocytosis: Case Report and Review of the Literature.

Mastocytosis is a rare infiltrative disorder characterized by mast cell proliferation within the skin and various extra-cutaneous organ systems. We report the case of a full-term neonate admitted to the neonatal intensive care unit for evaluation of diffuse skin lesions on her face, trunk and extremities. Initially, the lesions appeared to be consistent with a blueberry muffin rash. However, over a period of days the lesions became vesicular and changed in shape and number. The neonate underwent evaluation for infective etiologies, skin biopsy of the lesions, and flow cytometry analysis of the peripheral blood. The surgical pathology examination of the skin biopsy demonstrated mast cells consistent with a diagnosis of cutaneous mastocytosis. A review of relevant literature is also provided.

Sex Differences in Context Fear Generalization and Recruitment of Hippocampus and Amygdala during Retrieval.

Anxiety disorders are commonly associated with increased generalization of fear from a stress- or trauma-associated environment to a neutral context or environment. Differences in context-associated memory in males and females may contribute to increased susceptibility to anxiety disorders in women. Here we examined sex differences in context fear generalization and its neural correlates. We observed stronger context fear conditioning and more generalization of fear to a similar context in females than males. In addition, context preexposure increased fear conditioning in males and decreased generalization in females. Accordingly, males showed stronger cFos activity in dorsal hippocampus during memory retrieval and context generalization, whereas females showed preferential recruitment of basal amygdala. Together, these findings are consistent with previous research showing that hippocampal activity correlates with reduced context fear generalization. Differential competition between hippocampus and amygdala-dependent processes may thus contribute to sex differences in retrieval of context fear and greater generalization of fear-associated memory.