Disease diagnosis and arthroplasty type are strongly associated with short-term postoperative patient-reported outcomes in patients undergoing primary total shoulder arthroplasty.

BACKGROUND: Prognostic factors for total shoulder arthroplasty (TSA) clinical outcomes are incompletely understood. This study investigates the associations of preoperative patient, disease-specific, and surgical factors with 1-year postoperative PENN Shoulder Score (PSS) in patients undergoing primary TSA. METHODS: Cleveland Clinic patients undergoing primary anatomic TSA (aTSA) or reverse TSA (rTSA) for glenohumeral osteoarthritis (GHOA) or rotator cuff tear arthropathy (CTA) between February 2015 and August 2019, and having complete preoperative and 1-year postoperative patient-reported outcome measures (PROMs), were included. Twenty preselected preoperative patient, disease-specific, and surgical factors were used to fit multivariable models for 1-year PSS and its subscores. RESULTS: Of 1427 eligible primary TSAs, 1174 had 1-year follow-up by PROMs (82%), with 1042 analyzed after additional exclusions, including 30% rTSAs for CTA (n = 308), 26% rTSAs for GHOA (n = 275), and 44% aTSAs for GHOA (n = 459). All PROMs showed statistically significant improvements postoperatively, with 89% of patients reaching an acceptable symptom state. Lower 1-year PSS was associated with younger age, female sex, current smoking, chronic pain diagnosis, history of prior surgery, worker's compensation claim, lower preoperative mental health, lower baseline PSS, absence of glenoid bone loss, and diagnosis-arthroplasty type (CTA-rTSA < GHOA-rTSA < GHOA-aTSA). The most important prognostic factors associated with 1-year PSS were diagnosis-arthroplasty type, baseline mental health status, and insurance status. CONCLUSIONS: Disease diagnosis, arthroplasty type, and several other baseline factors are strongly and individually associated with PROMs following primary TSA, with patients undergoing aTSA for GHOA demonstrating the highest PROM scores at 1-year follow-up. Patient, disease-specific, and surgical factors can be used to guide postoperative prognosis following primary TSA for improved preoperative patient counseling regarding expected outcomes of these procedures.

How to avoid baseplate failure: the effect of compression and reverse shoulder arthroplasty baseplate design on implant stability.

BACKGROUND: Failure to achieve fixation of the glenoid baseplate will lead to clinical failure. The fixation of the baseplate to the scapula must be able to withstand sufficient shear forces to allow bony ingrowth. The importance of compression to neutralize the forces at the baseplate-bone interface has been assumed to be critical in limiting excessive micromotion. The purpose of this study is to determine the effect of compression on implant stability with different baseplate designs. METHODS: Various baseplate designs (1-piece monolithic central screw [1P], 2-piece locking central screw [2PL], and 2-piece nonlocking center screw [2PNL]) were investigated at 3 different compressive forces (high [810 N], medium [640 N], and low [530 N]). Synthetic bone cylinders were instrumented, and peripheral screws were used in all models. The combination of 1 locking and 3 nonlocking peripheral screw fixation was selected as worst-case scenario. Dynamic testing protocol followed the ASTM F2028-17 standard. The baseplate micromotion at high compression was compared to low compression. Additionally, the baseplate micromotion for each design was compared at baseline (first 50 cycles) and at 10,000 cycles for the 3 different compressive forces where motion above 150 µm was defined as failure. RESULTS: Baseplate micromotion was found to negatively correlate with compression (rpb = -0.83, P < .0001). At baseline, all baseplate designs were considered stable, regardless of compression. With high compression, average micromotion at the glenoid baseplate-bone interface remained below the 150-µm threshold for all baseplate designs at 10,000 cycles (1P: 50 ± 10 µm; 2PL: 78 ± 32 µm; 2PNL: 79 ± 8 µm; P = .060). With medium compression, average micromotion at 10,000 cycles for all 3 designs remained below the 150-µm threshold (1P: 88 ± 22 µm; 2PL: 132 ± 26 µm; 2PNL: 107 ± 39 µm). The 2PL design had the highest amount of micromotion (P = .013). With low compression, both 2-piece designs had an average micromotion above the 150-µm threshold whereas the 1-piece design did not (1P: 133 ± 35 µm; 2PL: 183 ± 21 µm; 2PNL: 166 ± 39 µm). The 2PL design had significantly higher micromotion when compared to 1P design (P = .041). DISCUSSION: The stability of a central screw baseplate correlates with the amount of compression obtained and is affected by implant design. For the same amount of compression, more micromotion is observed in a 2-piece design than a 1-piece design.

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.

One-year patient-reported outcomes following primary arthroscopic rotator cuff repair vary little by surgeon.

Background: This study's purpose was to investigate the extent to which differences among operating surgeons may influence 1-year patient-reported outcome measures (PROMs) in patients undergoing rotator cuff repair (RCR) surgery, after controlling for general and disease-specific patient factors. We hypothesized that surgeon would be additionally associated with 1-year PROMs, specifically the baseline to 1-year improvement in Penn Shoulder Score (PSS). Methods: We used mixed multivariable statistical modeling to assess the influence of surgeon (and alternatively surgical case volume) on 1-year PSS improvement in patients undergoing RCR at a single health system in 2018, controlling for eight patient- and six disease-specific preoperative factors as possible confounders. Contributions of predictors to explaining variation in 1-year PSS improvement were measured and compared using Akaike's Information Criterion. Results: 518 cases performed by 28 surgeons met inclusion criteria, with median (quartiles) baseline PSS of 41.9 (31.9, 53.9) and 1-year PSS improvement of 42 (29.1, 55.3) points. Contrary to expectation, surgeon and surgical case volume were neither statistically significantly nor clinically meaningfully associated with 1-year PSS improvement. Baseline PSS and mental health status (VR-12 MCS) were the dominant and only statistically significant predictors of 1-year PSS improvement, with lower baseline PSS and higher VR-12 MCS predicting larger 1-year PSS improvement. Conclusion: Patients generally reported excellent 1-year outcomes following primary RCR. This study did not find evidence that the individual surgeon or surgeon case volume influences 1-year PROMs, independently of case-mix factors, following primary RCR in a large employed hospital system.

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.

Understanding Medical Optimization for Patients Undergoing Shoulder Arthroplasty.

Many surgeons seek to optimize their patients' comorbid conditions preoperatively to reduce postoperative complications. To effectively optimize patients before total shoulder arthroplasty, the surgeon should be familiar with recognizing and treating common medical comorbidities found in an orthopedic patient including anemia, diabetes, malnutrition, cardiovascular conditions, and history of deep venous thrombosis. Screening for depression or other mental illness should also be conducted preoperatively and managed accordingly before surgery. Preoperative opioid use and smoking have significant effects on postoperative outcomes and should be addressed before surgery.

The Influence of Reverse Total Shoulder Arthroplasty Implant Design on Biomechanics.

PURPOSE OF REVIEW: As reverse total shoulder arthroplasty indications have expanded and the incidence of its use has increased, developments in implant design have been a critical component of its success. The purpose of this review is to highlight the recent literature regarding the effect of implant design on reverse total shoulder arthroplasty biomechanics. RECENT FINDINGS: Implant design for reverse total shoulder arthroplasty has evolved considerably from the modern design developed by Paul Grammont. The Grammont design had a medialized center of rotation and distalized humerus resulting from a 155° humeral neck shaft angle. These changes intended to decrease the forces on the glenoid component, thereby decreasing the risk for implant loosening and improving the deltoid moment arm. However, these features also led to scapular notching. The Grammont design has been modified over the last 20 years to increase the lateral offset of the glenosphere and decrease the prosthetic humeral neck shaft angle to 135°. These changes were made to optimize functional range of motion while minimizing scapular notching and improving active external rotation strength. Lastly, the introduction of preoperative planning and patient-specific instrumentation has improved surgeon ability to accurately place implants and optimize impingement-free range of motion. Success and durability of the reverse total shoulder arthroplasty has been contingent upon changes in implant design, starting with the Grammont-style prosthesis. Current humeral and glenoid implant designs vary in parameters such as humeral and glenoid offset, humeral tray design, liner thickness, and neck-shaft angle. A better understanding of the biomechanical implications of these design parameters will allow us to optimize shoulder function and minimize implant-related complications after reverse total shoulder arthroplasty.

Prevalence of Orthopedic Manifestations in Patients With Cardiac Amyloidosis With a Focus on Shoulder Pathologies.

Transthyretin cardiac amyloidosis (ATTR-CA) is a restrictive cardiomyopathy that has been associated with multiple orthopedic pathologies years before it manifests in the heart. There have been no studies on the prevalence of a wide range of shoulder pathologies in patients with cardiac amyloidosis (CA). Due to the preferential deposition of transthyretin in the soft tissues and joints, we predicted a greater prevalence of shoulder pathologies and other orthopedic manifestations in patients with ATTR-CA. This single-center, retrospective, case-control study, analyzed 1,310 patients with CA, 830 with ATTR-CA, and 480 with light-chain CA (AL-CA) from a dedicated CA REDcap database. Odds ratios comparing patients with CA to the age-matched published estimate of over 300 million patients in the general population were determined for shoulder, hip, and knee arthroplasty. Years between a patient's first shoulder pathology (i.e., shoulder arthroplasty) and the year of their diagnosis with CA were determined using data from patients with a known date of surgery. Overall, patients with ATTR-CA compared with patients with AL-CA presented more frequently with shoulder pathologies (p <0.001) and at least 1 orthopedic manifestation (p <0.001). The odds of patients with ATTR-CA and AL-CA aged 60 years or older who underwent shoulder arthroplasty was 6.05 times greater (95% confidence interval 4.26 to 8.60) and 1.63 times greater (95% confidence interval 0.67 to 3.94), respectively, compared with age-matched controls. Shoulder pathologies and concomitant orthopedic pathologies are common in patients with ATTR-CA and may help identify patients with CA earlier in their disease progression for earlier intervention and treatment.

Agreement between intraoperative and magnetic resonance imaging assessments of rotator cuff pathology and 2 magnetic resonance imaging-based assessments of supraspinatus muscle atrophy.

Background: Magnetic resonance imaging (MRI)-based rotator cuff assessment is often qualitative and subjective; few studies have tried to validate such preoperative assessments. This study investigates relationships of preoperative MRI assessments made by conventional approaches to intraoperative findings of tear type, location, and size or MRI-assessed muscle occupation ratio. Methods: Intraoperatively, surgeons assessed tear type, location, anterior-posterior (AP) width, and medial-lateral length in 102 rotator cuff repair patients. Two musculoskeletal radiologists independently assessed the preoperative MRI scans for these same parameters and supraspinatus muscle atrophy by both Warner classification and quantitative occupation ratio. Exact agreement proportions, kappa statistics, and correlation coefficients were used to quantify agreement relationships. Results: Agreement between MRI readers' and surgeons' observations of tear status averaged 93% with κ = 0.38, and that of tear location averaged 77% with κ = 0.50. Concordance correlations of MRI and intraoperative measures of anterior-posterior and medial-lateral tear length averaged 0.59 and 0.56 across readers, respectively. Despite excellent interrater agreement on Warner classification (exact agreement proportion 0.91) and occupation ratio (concordance correlation 0.93) separately, correlations between these 2 measures were -0.54 and -0.64 for the 2 readers, respectively. Patients with Warner grade 0 had occupation ratios ranging from 0.5 to 1.5. Conclusion: Correlations of preoperative MRI tear dimensions and muscle atrophy assessed by conventional approaches with intraoperatively measured tear dimensions and quantitative occupation ratio, respectively, were only fair. Since tear size and muscle atrophy are known strong predictors of outcomes following rotator cuff repair that may influence treatment decisions, surgeons need to be aware of the limitations of MRI methods. Continued development and validation of quantitative preoperative imaging methods to accurately assess these parameters are needed to improve surgical planning and prognosis.

New Approaches to the Diagnosis and Management of Periprosthetic Joint Infection of the Shoulder.

Periprosthetic joint infection (PJI) of the shoulder is a potentially devastating complication following shoulder arthroplasty. It is important to review the workup of PJI in the shoulder, including recently developed diagnostic criteria for shoulder PJI, along with detailed examination of the most common causative organism, Cutibacterium acnes. Treatment strategies for PJI of the shoulder include antibiotic therapy, surgical options, and what to do with unexpected positive cultures in revision arthroplasty. Surgeons should be familiar with bony and soft-tissue reconstructive options following explantation of an infected shoulder prosthesis.

What do positive and negative Cutibacterium culture results in periprosthetic shoulder infection mean? A multi-institutional control study.

BACKGROUND: Deep tissue culture specimens obtained at the time of revision shoulder arthroplasty are commonly positive for Cutibacterium. Clinical interpretation of positive cultures can be difficult. This was a multi-institutional study evaluating the accuracy of cultures for Cutibacterium using positive control (PC) and negative control (NC) samples. The relationship between time to culture positivity and strength of culture positivity was also studied. METHODS: Eleven different institutions were each sent 12 blinded samples (10 PC and 2 NC samples). The 10 PC samples included 2 sets of 5 different dilutions of a Cutibacterium isolate from a failed total shoulder arthroplasty with a probable periprosthetic infection. At each institution, the samples were handled as if they were received from the operating room. Specimen growth, time to culture positivity, and strength of culture positivity (based on semiquantitative assessment) were reported. RESULTS: A total of 110 PC samples and 22 NC samples were tested. One hundred percent of specimens at the 4 highest dilutions were positive for Cutibacterium. At the lowest dilution, 91% of samples showed positive findings. Cutibacterium grew in 14% of NC samples. Cutibacterium grew in PC samples at an average of 4.0 ± 1.3 days, and all of these samples showed growth within 7 days. The time to positivity was significantly shorter (P < .001) and the strength of positivity was significantly higher (P < .001) in true-positive cultures compared with false-positive cultures. CONCLUSIONS: This multi-institutional study suggests that different institutions may report highly consistent rates of culture positivity for revision shoulder arthroplasty samples with higher bacterial loads. In contrast, with lower bacterial loads, the results are somewhat less consistent. Clinicians should consider using a shorter time to positivity and a higher strength of positivity as adjuncts in determining whether a tissue culture sample is a true positive.

Validation of a 3D CT imaging method for quantifying implant migration following anatomic total shoulder arthroplasty.

Glenoid component loosening remains a common complication following anatomic total shoulder arthroplasty (TSA); however, plain radiographs are unable to accurately detect early implant migration. The purpose of this study was to validate the accuracy of a method of postoperative, three-dimensional (3D) computed tomography (CT) imaging with metal artifact reduction (MAR) to detect glenoid component migration following anatomic TSA. Tantalum bead markers were inserted into polyethylene glenoid components for implant detection on 3D CT. In-vitro validation was performed using a glenoid component placed into a scapula sawbone and incrementally translated and rotated, with MAR 3D CT acquired at each test position. Accuracy was evaluated by root mean square error (RMSE). In-vivo validation was performed on six patients who underwent anatomic TSA, with two postoperative CT scans acquired in each patient and marker-based radiostereometric analysis (RSA) performed on the same days. Glenoid component migration was calculated relative to a scapular coordinate system for both MAR 3D CT and RSA. Accuracy was evaluated by RMSE and paired Student's t-tests. The largest RMSE on in-vitro testing was 0.24 mm in translation and 0.11° in rotation, and on in-vivo testing was 0.47 mm in translation and 1.04° in rotation. There were no significant differences between MAR 3D CT and RSA measurement methods. MAR 3D CT imaging is capable of quantifying glenoid component migration with a high level of accuracy. MAR 3D CT imaging is advantageous over RSA because it is readily available clinically and can also be used to evaluate the implant-bone interface.

Changes From Baseline in Patient- Reported Outcomes at 1 Year Versus 2 Years After Rotator Cuff Repair: A Systematic Review and Meta-analysis.

BACKGROUND: Most orthopaedic journals currently require reporting outcomes of surgical interventions for at least 2 postoperative years, but there have been no rigorous studies on this matter. Various patient-reported outcome (PRO) measures (PROMs) have been used to assess the status of the shoulder after rotator cuff repair (RCR). HYPOTHESIS: We hypothesized that the mean shoulder-specific PROMs at 1 year improve substantially over baseline but that there is no clinically meaningful difference between the mean 1- and 2-year PROMs after RCR. STUDY DESIGN: Meta-analysis; Level of evidence, 2. METHODS: We conducted a systematic review of published randomized controlled trials (RCTs) and prospective cohort studies (level of evidence 1 and 2) reporting the shoulder-specific American Shoulder and Elbow Surgeons (ASES), the Constant, or the Western Ontario Rotator Cuff (WORC) Index scores at baseline, 1 year, and 2 years after RCR. The methodologic quality of studies was assessed. Also, the random effects meta-analyses of changes in PROMs for each of the first and second postoperative years were conducted. RESULTS: Fifteen studies (n = 11 RCTs; n = 4 cohort studies) with a total of 1371 patients were included. Studies were highly heterogeneous, but no visual evidence of major publication bias was observed. The weighted means of the baseline PROMs were 46.2 points for the ASES score, 46.4 points for the Constant score, and 38.8 points for the WORC Index. The first-year summary increments were 41.1 (95% CI, 36.0-46.2) points for the ASES score, 34.2 (95% CI, 28.8-39.6) points for the Constant score, and 42.9 (95% CI, 37.3-48.4) points for the WORC Index. In contrast, the second-year summary increments were 2.3 (95% CI, 1-3.6) points for the ASES score, 3.2 (95% CI, 1.9-4.4) points for the Constant score, and 2 (95% CI, -0.1 to 4) points for the WORC Index. CONCLUSION: All PROMs improved considerably from baseline to 1 year, but only very small gains that were below the minimal clinically important differences were observed between 1 year and 2 years after RCR. This study did not find any evidence for requiring a minimum of 2 years of follow-up for publication of PROs after RCR. Our results suggest that focusing on 1-year PROMs after RCR would foster more timely reporting, better control of selection bias, and better allocation of research resources.

Effectiveness of a Web-Based Electronic Prospective Data Collection Tool for Surgical Data in Shoulder Arthroplasty.

BACKGROUND: The purpose of this study was to demonstrate the validity and efficiency of the Outcomes Management and Evaluation (OME) system, a prospectively designed electronic data collection tool, for collecting comprehensive and standardized surgical data in shoulder arthroplasty. METHODS: Surgical data from the first 100 cases of shoulder arthroplasty that were collected into the OME database were analyzed. Surgeons completed a traditional narrative operative note and also an OME case report using an encrypted smartphone. A blinded reviewer extracted data from the operative notes and implant logs in the electronic medical records (EMR) by manual chart review. OME and EMR data were compared with regard to data counts and agreement between 39 variables related to preoperative pathology, including rotator cuff status and glenoid wear, and surgical procedures. Data counts were assessed using both raw percentages and with McNemar's test (with continuity correction). Agreement of nominal variables was analyzed using Cohen's unweighted kappa (κ) and of ordinal variables using the linearly weighted Cohen's test. Efficiency was assessed by calculating the median time needed to complete OME. RESULTS: Compared to the EMR, the OME database had significantly higher data counts for 56% (22 of 39) of the variables assessed. A high level of proportional and statistical agreement was demonstrated between the data in the two datasets. 10 of 39 variables had 100% agreement but could not be statistically compared because both datasets had the same single response under those variables. Among the 29 variables that were compared, 79% (23 of 29) of variables had >80% raw proportional agreement, and 69% (20 of 29) of variables showed at least substantial agreement (κ > 0.6). The median time for completing OME surgery data entry was 92 seconds (IQR 70 - 126). CONCLUSION: The prospectively designed, electronic data entry system (OME) is an efficient and valid tool for collecting comprehensive and standardized surgical data on shoulder arthroplasty. LEVEL OF EVIDENCE: Level IV.

Stepped Augmented Glenoid Component in Anatomic Total Shoulder Arthroplasty for B2 and B3 Glenoid Pathology: A Study of Early Outcomes.

BACKGROUND: Posterior glenoid bone loss is commonly associated with primary glenohumeral osteoarthritis. Surgical management of bone loss in anatomic total shoulder arthroplasty (aTSA) remains controversial. We studied the use of a stepped augmented glenoid component for management of Walch B2 and B3 glenoids and compared the radiographic and clinical outcomes at short-term follow-up with those achieved with a non-augmented component of the same design in Walch A1 glenoids. METHODS: Ninety-two patients (42 A1, 29 B2, and 21 B3 glenoids) were prospectively followed after aTSA. Sequential 3-dimensional (3D) computed tomography (CT) imaging was performed preoperatively, within 3 months postoperatively with metal artifact reduction (MAR) to define implant position, and at a minimum of 2 years postoperatively with MAR. Scapular 3D registration with implant registration allowed 3D measurement of glenoid implant position, implant shift, and central peg osteolysis (CPO). RESULTS: CPO with or without implant shift occurred in a higher percentage of B3 glenoids treated with the augmented glenoid component (29%) than A1 glenoids treated with a standard component (5%) (p = 0.028). There was no significant difference in the frequency of CPO between B2 glenoids with the augmented component (10%) and A1 glenoids with the standard component. There was no difference in postoperative glenoid component version and inclination between groups. B3 glenoids were associated with more component medialization relative to the premorbid joint line compared with A1 and B2 glenoids (p < 0.001). CONCLUSIONS: A stepped augmented glenoid component can restore premorbid glenoid anatomy in patients with asymmetric biconcave glenoid bone loss (Walch B2), with short-term clinical and radiographic results equivalent to those for patients without glenoid bone loss (Walch A1) treated with a non-augmented component. There is a greater risk of CPO in patients with moderate-to-severe B3 glenoid pathology with this stepped augmented glenoid component. Longer follow-up will help define the clinical implications of CPO over time. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.