The Relationship Between Design-Based Lateralization, Humeral bearing design, Polyethylene Angle, and Patient-Related Factors on Surgical Complications after Reverse Shoulder Arthroplasty: A Machine Learning Analysis.

INTRODUCTION: Technological advancements in implant design and surgical technique have focused on diminishing complications and optimizing performance of reverse shoulder arthroplasty (RSA). Despite this, there remains a paucity of literature correlating prosthetic features and clinical outcomes. This investigation utilized a machine learning approach to evaluate the effect of select implant design features and patient-related factors on surgical complications after RSA. METHODS: Over a 16-year period (2004 - 2020), all primary RSA performed at a single institution for elective and traumatic indications with a minimum follow-up of 2 years were identified. Parameters related to implant design evaluated in this study included inlay vs onlay humeral bearing design, glenoid lateralization (medialized or lateralized), humeral lateralization (medialized, minimally lateralized, or lateralized), global lateralization (medialized, minimally lateralized, lateralized, highly lateralized, or very highly lateralized), stem to metallic bearing neck shaft angle (NSA), and polyethylene NSA. Machine learning models predicting surgical complications were constructed for each patient and Shapley additive explanation (SHAP) values were calculated to quantify feature importance. RESULTS: A total of 3,837 RSAs were identified, of which 472 (12.3%) experienced a surgical complication. Those experiencing a surgical complication were more likely to be current smokers (Odds ratio [OR] = 1.71; P = .003), have prior surgery (OR = 1.60; P < .001), have an underlying diagnosis of sequalae of instability (OR = 4.59; P < .001) or non-union (OR = 3.09; P < .001), and required longer OR times (98 vs. 86 minutes; P < .001). Notable implant design features at an increased odds for complications included an inlay humeral component (OR = 1.67; P < .001), medialized glenoid (OR = 1.43; P = .001), medialized humerus (OR = 1.48; P = .004), a minimally lateralized global construct (OR = 1.51; P < .001), and glenohumeral constructs consisting of a medialized glenoid and minimally lateralized humerus (OR = 1.59; P < .001), and a lateralized glenoid and medialized humerus (OR = 2.68; P < .001). Based on patient- and implant-specific features, the machine learning model predicted complications after RSA with an area under the receiver operating characteristic curve (AUC ROC) of 0.61. CONCLUSIONS: This study demonstrated that patient-specific risk factors had a more substantial effect than implant design configurations on the predictive ability of a machine learning model on surgical complications after RSA. However, certain implant features appeared to be associated with a higher odd of surgical complications.

After Primary Shoulder Arthroplasty Appropriate Vancomycin Antibiotic Prophylaxis Does Not Lead to Increased Infectious Complications When Compared to Cefazolin.

INTRODUCTION: In primary shoulder arthroplasty (SA), intravenous (IV) cefazolin has demonstrated lower rates of infectious complications when compared to IV vancomycin. However, previous analyses included SA cohorts with both complete and incomplete vancomycin administration. Therefore, it is currently unclear whether cefazolin still maintains a prophylactic advantage to vancomycin when it is appropriately indicated and sufficiently administered at the time of surgical incision. This study evaluated the comparative efficacy of cefazolin and complete vancomycin administration for surgical prophylaxis in primary shoulder arthroplasty with respect to infectious complications. METHODS: A retrospective cohort study was conducted utilizing a single institution total joint registry database, where all primary SA types (hemiarthroplasty, anatomic total shoulder arthroplasty, reverse shoulder arthroplasty) performed between 2000 to 2019 for elective and trauma indications using IV cefazolin or complete vancomycin administration as the primary antibiotic prophylaxis were identified. Vancomycin was primarily indicated for patients with a severe self-reported penicillin or cephalosporin allergy and/or MRSA colonization. Complete administration was defined as at least 30 minutes of antibiotic infusion prior to incision. All included SA had at least 2 years of clinical follow-up. Multivariable Cox proportional hazard regression was used to evaluate all-cause infectious complications including survival free of prosthetic joint infection (PJI). RESULTS: The final cohort included 7,177 primary SA, 6,879 (95.8%) received IV cefazolin and 298 (4.2%) received complete vancomycin administration. Infectious complications occurred in 120 (1.7%) SA leading to 81 (1.1%) infectious reoperations. Of the infectious complications 41 (0.6%) were superficial infections and 79 were (1.1%) PJIs. When categorized by administered antibiotics, there were no differences in rates of all infectious complications (1.6% vs. 2.3%; P = .352), superficial complications (0.5% vs. 1.3%; P = .071), PJI (1.1% vs. 1.0%; P = .874), or infectious reoperations (1.1% vs. 1.0%; P = .839). On multivariable analyses, complete vancomycin infusion demonstrated no difference in rates of infectious complications compared to cefazolin administration (hazard ratio [HR], 1.50 [95% confidence interval (CI), 0.70 to 3.25]; P = .297), even when other independent predictors of PJI (male sex, prior surgery, and Methicillin-resistant Staphylococcus aureus colonization) were considered. CONCLUSIONS: In comparison to cefazolin, complete administration of vancomycin (infusion to incision time greater than 30 minutes) as the primary prophylactic agent does not adversely increase the rates of infectious complications and PJI. Prophylaxis protocols should promote appropriate indications for the use of cefazolin or vancomycin, and when necessary, ensure complete administration of vancomycin to mitigate additional infectious risks after primary SA.

Reverse shoulder arthroplasty megaprosthesis for surgical management of severe proximal humeral bone loss.

BACKGROUND: Shoulder arthroplasty in the setting of severe proximal humerus bone loss can be challenging. The purpose of this study was to evaluate the outcomes of a modular segmental megaprosthesis when implanted in a reverse configuration for complex primary arthroplasty, reconstruction at the time of oncologic resection, and revision shoulder arthroplasty. MATERIALS AND METHODS: A Joint Registry Database was queried to identify all shoulder arthroplasties performed at a single institution using the Comprehensive Segmental Revision System reverse shoulder arthroplasty (SRS-RSA; Zimmer Biomet). A retrospective review of electronic medical records and radiographs was performed to record demographic data, indication, outcomes, complications, and revision surgery. RESULTS: Between February 2012 and October 2022, a total of 76 consecutive SRS-RSAs were implanted. An analysis of patients with minimum 12-month follow-up yielded 53 patients with a mean follow-up of 4.1 ± 2.43 years. Surgical complication rate in this cohort was observed in 41.5% (22 of 53) of cases. Overall, the revision rate at final follow-up was 26.4% (14 of 53), with a significant difference between the primary and revision cohorts. The number of prior surgeries was a significant risk factor for revision surgery, with a hazard ratio of 1.789 (95% confidence interval 1.314-2.436, P < .001). When analyzing aseptic humeral loosening rates across study cohorts, a significant difference was found between the primary arthroplasty (0%, n = 0) and the revision arthroplasty cohorts (22.2%, n = 6) (P = .04). DISCUSSION: Reverse shoulder arthroplasty using a modular segmental megaprosthesis remains a reasonable salvage option for shoulder reconstruction in the setting of proximal humeral bone loss. Because of the substantial bone loss and soft tissue deficiencies typically present in these cases, surgeons should educate patients on the relatively high complication rate, particularly when used in the setting of a previous failed arthroplasty.

Impact of sickle cell disease in shoulder arthroplasty: a matched cohort analysis.

BACKGROUND: Sickle cell disease (SCD) is a genetic disorder of abnormal hemoglobin synthesis that is known to cause glenohumeral avascular necrosis (AVN). Little has been published on the use of shoulder arthroplasty (SA) for the treatment of glenohumeral AVN in SCD. We report on the clinical and radiographic results and postoperative complications following SA in the patient cohort. METHODS: A retrospective review was performed identifying 17 primary SAs (9 hemiarthroplasties, 7 anatomic total SAs, and 1 reverse total SA) in patients with a confirmed diagnosis of SCD and a minimum of 2-year follow-up. This cohort was matched (1:2) according to age, sex, body mass index, type of prosthesis, and year of surgery with patients who had undergone hemiarthroplasty or total SA for osteoarthritis (OA) or reverse total SA for cuff tear arthropathy. Outcomes included the visual analog scale (VAS) for pain, American Shoulder and Elbow Surgeons score, range of motion, and strength measurements in forward elevation (FE), external rotation (ER), and internal rotation (IR). RESULTS: Our cohort included 9 (52.9%) men with a mean age of 43 yr. The average follow-up time was 5.9 yr. In patients with SCD, SA provided significant improvements in VAS pain (9.1-3.8; P < .001), FE (95°-128°; P < .001), ER (24°-38°; P < .001), IR score (3.2-5.2; P < .001), FE strength (4.2-4.8; P < .001), ER strength (4.1-4.7; P < .001), IR strength (4.1-4.7; P < .001), and American Shoulder and Elbow Surgeons scores (48.6-73.5; P < .001). When compared to the matched cohort, the SCD group demonstrated higher preoperative (9.1 vs. 3.8; P < .001) and postoperative VAS scores (3.8 vs. 1.3; P < .001). Other clinical outcomes demonstrated no significant differences. There were 5 (29%) complications, 2 (11.8%) episodes of sickle cell crisis, and 3 (18%) reoperations in the SCD cohort. When compared to the matched cohort, there were no statistical differences with respect to complications (29% vs. 12%; P = .140) or reoperations (18% vs. 12%; P = .387). CONCLUSIONS: SA is an effective treatment modality for glenohumeral AVN in patients with SCD. Patients may expect improvements in pain, function, motion, and strength. However, final postoperative pain relief may be less than those treated with SA without SCD. Unique perioperative management is necessary to mitigate the risk of postoperative sickle cell crises.

Higher rates of mortality and perioperative complications in patients undergoing primary shoulder arthroplasty and a history of previous stroke.

BACKGROUND: Cerebrovascular accidents (CVAs), or strokes, are the second most common cause of mortality and third most common cause of disability worldwide. Although advances in the treatment of strokes have improved survivorship following these events, there remains a limited understanding of the effect of a prior stroke and sequelae on patients undergoing shoulder arthroplasty (SA). This study aimed to determine the outcomes of patients with a history of stroke with sequela undergoing primary SA. METHODS: Over a 30-year time period (1990-2020), 205 primary SAs (32 hemiarthroplasties [HAs], 56 anatomic total shoulder arthroplasties [aTSAs], and 117 reverse shoulder arthroplasties [RSAs]) were performed in patients who sustained a previous stroke with sequela and were followed for a minimum of 2 years. This cohort was matched (1:2) according to age, sex, body mass index, implant, and year of surgery with patients who had undergone HA or aTSA for osteoarthritis or RSA for cuff tear arthropathy. Mortality after primary SA was individually calculated through a cumulative incidence analysis. Implant survivorship was analyzed with a competing risk model selecting death as the competing risk. RESULTS: The stroke cohort sustained 38 (18.5%) surgical and 42 (20.5%) medical perioperative complications. Compared with the control group, the stroke cohort demonstrated higher rates of any surgical complication (18.5% vs 10.7%; P = .007), instability (6.3 % vs 1.7%; P = .002), venous thromboembolism (3.4% vs 0.5%; P = .004), pulmonary embolus (2.0% vs 0%; P = .005), postoperative stroke (2.4% vs 0%; P = .004), respiratory failure (1.0% vs 0%; P = .045), any medical complication (20.5% vs 7.3%; P < .001), and 90-day readmission (16.6% vs 4.9%; P < .001). Additionally, RSA in the stroke cohort was associated with higher reoperation (8.5% vs 2.6%; P = .011) and revision rates (6.8% vs 1.7%; P = .013) compared with the matched cohort. Subsequent cumulative incidences of death at 1, 2, 5, 10, 15, and 20 years were 4.4% vs 3.4%, 10.7% vs 5.1%, 25.6% vs 14.7%, 51.6% vs 39.3%, 74.3% vs 58.6%, and 92.6% vs 58.6% between the stroke and matched cohorts, respectively (P < .001). CONCLUSIONS: A preoperative diagnosis of a stroke in patients undergoing primary SA is associated with higher rates of perioperative complications and mortality when compared to a matched cohort. This information should be considered to counsel patients and surgeons to optimize care and help mitigate risks associated with the perioperative period.

When intravenous vancomycin prophylaxis is needed in shoulder arthroplasty, incomplete administration is associated with increased infectious complications.

BACKGROUND: Vancomycin is often used as antimicrobial prophylaxis for shoulder arthroplasty (SA) either when first generation cephalosporins are contraindicated or colonization with resistant bacteria is anticipated. In general, vancomycin necessitates longer infusion times to mitigate potential side effects. When infusion is started too close to the time of the incision, administration may not be complete during surgery. This study evaluated whether incomplete administration of intravenous vancomycin prior to SA affects the rate of infectious complications. METHODS: Between 2000 and 2019, all primary SA types (hemiarthroplasty, anatomic total SA, reverse SA) performed at a single institution for elective and trauma indications using intravenous vancomycin as the primary antibiotic prophylaxis and a minimum follow-up of 2 yr were identified. The time between the initiation of vancomycin and skin incision was calculated. Complete administration was defined as at least 30 min of infusion prior to incision. Demographic characteristics and infectious complications including survival free of prosthetic joint infection (PJI) were generated. Multivariable analyses were conducted to evaluate the association between vancomycin timing and the development of PJI. RESULTS: A total of 461 primary SAs were included. Infusion was incomplete (< 30 minutes preoperatively) for 163 [35.4%] SA and complete (> 30 minutes preoperatively) for 298 [64.6%] SAs. The incomplete group demonstrated higher rates of any infectious complication (8% vs. 2.3%; P = .005), PJI (5.5% vs. 1%; P = .004), and reoperation inclusive of revision due to infectious complications (4.9% vs. 1%; P = .009). Survivorship free of PJI was worse in SA with incomplete compared to those with complete vancomycin administration. Survival rates for incomplete and complete administration were 97.6% and 99.3% at 1 mo, 95.7% and 99.0% at 2 yr, 95.1% and 99.0% at 5 yr, and 93.9% and 99.0% at 20 yr, respectively (P = .006). Multivariable analyses confirmed that incomplete vancomycin administration was an independent risk factor for PJI compared with complete administration (hazard ratio, 4.22 [95% confidence interval, 1.12-15.90]; P = .033), even when other independent predictors of PJI (age, male sex, prior surgery, methicillin-resistant Staphylococcus aureus colonization, and follow-up) were considered. CONCLUSIONS: When vancomycin is the primary prophylactic agent used at the time of primary SA, incomplete administration (infusion to incision time under 30 min) seems to adversely increase the rates of infectious complications and PJI. Prophylaxis protocols should ensure that complete vancomycin administration is achieved to minimize infection after SA.

Shoulder arthroplasty after prior external beam radiation therapy: a matched cohort analysis.

BACKGROUND: External beam radiation therapy (XRT) is a commonly used therapeutic modality for the treatment of various chest wall and axillary malignancies. Despite the known risk of local soft tissue dysfunction, and possibly compromised bone ingrowth for cementless implants, there remains limited data on the impact of prior XRT in a shoulder arthroplasty (SA) cohort. This study evaluated the outcomes of primary SA in patients with prior XRT compared to a matched cohort (MC). METHODS: Over a 27-year time period (1993-2020), 80 primary SAs (7 hemiarthroplasties [HAs], 29 anatomic total shoulder arthroplasties [aTSAs], and 44 reverse shoulder arthroplasties [rTSAs]) with previous XRT to the upper chest or axillary region and a minimum of 2-year follow-up were included. This cohort was matched (1:2) according to age, sex, body mass index (BMI), implant, and year of surgery with patients who had undergone HA or TSA for osteoarthritis or RSA for cuff tear arthropathy. Clinical outcomes including pain, active shoulder range of motion (ROM), strength, complications, and reoperations inclusive of revision surgery were assessed. RESULTS: The XRT cohort consisted of 71 (88.8%) women with a mean age of 70.9 (range, 43-87) years, BMI of 30.9 ± 7.6, and follow-up period of 6.6 years (range, 2.0-28.2). In these patients, SA led to substantial improvements in pain, ROM, and strength across the entire cohort. When compared to the MC, the XRT group demonstrated a lower final postoperative forward elevation (FE) (111° vs. 126°; P = .013) and less improvements in pain (5.3 vs. 6.2; P = .002), FE (34° vs. 54°; P = .002), and external rotation (13° vs. 24°; P < .001). There were 14 (17.5%) complications and 7 reoperations in the XRT group, with rotator cuff failure after HA or TSA (n = 4 of 36; 11.1%) as the most common complication and no instances of loose humeral components. The XRT group had a higher rate of complications (17.5% vs. 8.1%; P = .03) but not reoperations (8.8% vs. 3.1%; P = .059). When evaluated by implant, rTSA demonstrated the lowest rate of reoperations followed by aTSA and HA (2.3% vs. 10.3% vs. 42.9%; P = .002). CONCLUSIONS: Primary SA is an effective treatment modality for the improvement of pain, motion, and strength in patients with a history of prior XRT. However, when compared to patients without prior XRT, less clinical improvement and a higher rate of postoperative complications were observed.

Prior bariatric surgery is associated with an increased rate of complications after primary shoulder arthroplasty independent of body mass index.

BACKGROUND: Bariatric surgery (BS) is a debated, yet commonly used, management strategy in the treatment of morbidly obese patients. Despite recent advances in BS techniques, there is limited data on the potential impact of prior BS in patients undergoing shoulder arthroplasty. This investigation evaluated the outcomes of primary shoulder arthroplasty (SA) in patients with prior BS when compared to matched controls. METHODS: Over a 31-year period (1989-2020), 183 primary SA (12 hemiarthroplasties [HAs], 59 anatomic total shoulder arthroplasties [aTSAs], and 112 reverse shoulder arthroplasties [RSAs]) in patients with prior BS and a minimum of 2-year follow-up had been performed at a single institution. This cohort was matched 1:1:1 according to age, sex, diagnosis, implant, American Society of Anesthesiologists score, Charlson Comorbidity Index, and SA surgical year to separate control groups of SA with no history of BS and a BMI of either <40 (low BMI group) or ≥40(high BMI group). Surgical complications, medical complications, reoperations, revisions, and implant survivorship were assessed. The mean follow-up time was 6.8 years (range, 2-21 years). RESULTS: The bariatric surgery cohort had a higher rate of any complication (29.5% vs. 14.8% vs. 14.2%; P < .001), surgical complications (25.1% vs. 12.6% vs. 12.6%; P = .002), and noninfectious complications (20.2% vs. 10.4% vs. 9.8%; low P = .009 and high P = .005) relative to both low and high BMI groups. For BS patients, the 15-year survivorship free of any complication was 55.6 (95% confidence interval [CI], 43.8%-70.5%) compared with 80.3% (95% CI, 72.3%-89.3%) in the low BMI group and 75.8% (65.6%-87.7%) in the high BMI group (P < .001). Comparisons of the bariatric and matched groups demonstrated no statistical differences between the risk of reoperation or revision surgery. When SA was performed within 2 years of BS, higher rates of complications (50% vs. 27.0%; P = .030), reoperations (35.0% vs. 8.0%; P = .002), and revisions (30.0% vs. 5.5%; P = .002) were observed. CONCLUSIONS: Primary shoulder arthroplasty in patients with prior bariatric surgery demonstrated an elevated complication profile when compared to matched cohorts of patients with no history of BS and either low or high BMI. These risks were more pronounced when shoulder arthroplasty was performed within 2 years of bariatric surgery. Care teams should be aware of the potential implications of the postbariatric metabolic state and investigate whether further perioperative optimization is warranted.

Increasing severity of preoperative anemia is associated with higher postoperative medical and surgical complications after primary shoulder arthroplasty.

BACKGROUND: Anemia is a major cause of morbidity worldwide and compounds numerous medical conditions. Studies have found associations between anemia and both medical and surgical complications after shoulder arthroplasty (SA); however, most of these studies have used commercially available national databases with limited information on outcomes and typically short-term follow-up. Our study sought to evaluate the midterm outcomes of primary SA at a single institution when stratified by the degree of preoperative anemia. METHODS: Between 2000 and 2020, 5231 primary SA (477 hemiarthroplasties, 2091 anatomic total SA, and 2335 reverse SA) with preoperative hematocrit values available and a minimum follow-up of 2 years were collected from a single-institution joint registry database. The severity of anemia was subclassified as no anemia (hematocrit >39% for males, >36% for females; n = 4194 [80.2%]), mild anemia (hematocrit 33%-39% for males, 33%-36% for females; n = 742 [14.2%]), and moderate-to-severe anemia (hematocrit <33% for both males and females; n = 295 [5.6%]). The mean follow-up time for the entire cohort was 5.9 years (range, 2-22 years). Medical and surgical complications, reoperations, revisions, and implant survivorship were assessed. RESULTS: SA with moderate-to-severe anemia had the highest rate of nonfatal and nontransfusion medical complications (5.1%) relative to the nonanemic (1.2%; P < .001) and mild anemic groups (1.5%; P < .001). Similarly, SA with moderate-to-severe anemia had the highest rate of surgical complications (19.3%) compared with mild anemia (14.3%; P = .044) and no anemia (11.6%; P < .001). Postoperative transfusion was most frequent in the moderate-to-severe anemia cohort (40.3%) compared with the mild anemia (14.2%; P < .001) and nonanemic groups (2.5%; P < .001). Furthermore, SA who received postoperative transfusions had a higher risk of nonfatal medical complications (8.2% vs. 1.0%; P < .001), 90-day mortality (1.5% vs. 0.03%; P = .001), and surgical complications (19.5% vs. 12.0%; P < .001) when compared with those without transfusion. CONCLUSIONS: Moderate-to-severe anemia (hematocrit <33% for both males and females) was identified in approximately 5.6% of patients who underwent SA at a single institution and was associated with increased medical and surgical complications. Patients who received postoperative transfusions presented elevated rates of medical complications, 90-day mortality, and surgical complications. Health care teams should be aware of these risks in order to provide more individualized medical optimization and postoperative monitoring.

Cost comparison and complication profiles of superior capsular reconstruction, lower trapezius transfer, and reverse shoulder arthroplasty for irreparable rotator cuff tears.

BACKGROUND: Irreparable rotator cuff tears (IRCTs) pose treatment challenges both clinically and financially. As cost-effectiveness initiatives are prioritized, value-based health care delivery models are becoming increasingly common. The purpose of this study was to perform a comprehensive analysis of the cost, complications, and readmission rates of 3 common surgical treatment options for IRCTs: superior capsular reconstruction (SCR), arthroscopically assisted lower trapezius tendon transfer (LTTT), and reverse shoulder arthroplasty (RSA). METHODS: Between 2018 and 2020, 155 patients who underwent shoulder surgery at a single institution for IRCT with minimal to no arthritis were identified. Procedures performed included 20 SCRs, 47 LTTTs, and 88 RSAs. A cost analysis was designed to include a period of 60 days preoperatively, the index surgical hospitalization, and 90 days postoperatively, including costs of any readmission or reoperation. RESULTS: Mean standardized costs were as follows: preoperative evaluation SCR $507, LTTT $507, and RSA $730; index surgical hospitalization SCR $19,675, LTTT $15,722, and RSA $16,077; and postoperative care SCR $655, LTTT $686, and RSA $404. Significant differences were observed in the index surgical costs (P < .001), with SCR incurring an additional average cost of $3953 and $3598 compared with LTTT and RSA, respectively. The 90-day complication, reoperation, and readmission rates were 0%, 0%, and 0% in the SCR group; 2.1%, 0%, and 0% in the LTTT group; and 3.4%, 0%, and 1.1% in the RSA group, respectively. With the numbers available, differences among the 3 surgical procedures with respect to complication (P = .223), reoperation (P = .999), and readmission rates (P = .568) did not reach statistical significance. CONCLUSIONS: The mean standardized costs for the treatment of 3 common IRCT procedures inclusive of 60-day workup and 90-day postoperative recovery were $16,915, $17,210, and $20,837 for LTTT, RSA (average added cost $295), and SCR (average added cost $3922), respectively. This information may provide surgeons and institutions with cost-related information that will become increasingly relevant with the expansion of value-based surgical reimbursements.

Clinical and radiographic outcomes of hybrid glenoid fixation with a central porous titanium post: analysis of 713 consecutive shoulders.

BACKGROUND: Hybrid glenoid component fixation represents an emerging technology in total shoulder arthroplasty (TSA) design. However, there is a paucity of larger-scale studies reporting the outcomes following implantation of these components. This study aimed to determine the outcomes following primary TSA using hybrid glenoid component fixation with a central porous titanium post. METHODS: A retrospective review of 2 institutional databases identified patients aged ≥ 18 years who underwent primary elective hybrid TSA between 2009 and 2018 with a minimum of 2 years of follow-up. Outcomes evaluated included the visual analog scale pain score, range of motion, American Shoulder and Elbow Surgeons (ASES) score, complications, and implant survivorship free from reoperation or revision. Postoperative imaging was assessed for glenoid radiolucent lines and evidence of aseptic glenoid component loosening (AGL). RESULTS: A total of 713 shoulders in 666 patients with a mean age of 61 ± 6 years were included in the study at a mean follow-up period of 4.3 years (range, 2.0-9.1 years); male shoulders comprised 50.9% of shoulders. Notable clinical improvements were observed with respect to the visual analog scale pain score (7.0 to 1.4, P < .001), active forward elevation (91° to 155°, P < .001), active external rotation (21° to 50°, P < .001), and the ASES score (38.6 to 82.7, P < .001), with all exceeding the substantial clinical benefit threshold for TSA. The active internal rotation score also showed significant improvement (3.1 to 5.7, P < .001). Glenoid radiolucent lines were identified in 57 TSAs (8.2%), with 1 radiographically loose glenoid component (0.1%). There were 54 complications (7.6%), with postoperative rotator cuff tear as the most common complication (n = 15, 2.1%); only 4 cases (0.6%) of glenoid-related complications (AGL) were observed. The Kaplan-Meier rate of survival free from revision surgery was 98.7% at 1 year, 98.5% at 2 years, and 96.7% at 5 years. CONCLUSIONS: Hybrid glenoid component fixation of anatomic TSA with a central porous titanium post demonstrated statistically significant and clinically meaningful improvements in pain, range of motion, and ASES scores. Although AGL remains a concern, only 0.6% of TSAs sustained glenoid-related complications at a mean follow-up period of 4.3 years and the rate of survivorship free from revision was 96.7% at 5 years. These favorable clinical findings support the theoretical advantages of hybrid glenoid fixation; however, large comparative investigations with long-term follow-up are needed to validate these results.

Analysis of patient characteristics and outcomes related to distance traveled to a tertiary center for primary reverse shoulder arthroplasty.

INTRODUCTION: The reasons for referral and travel patterns are lacking for patients undergoing reverse shoulder arthroplasty (RSA). The purpose of this study was to compare comorbidities, surgical time, cost and complications between local and distant primary RSA patients. METHODS: Between 2007 and 2015, 1,666 primary RSAs were performed at our institution. Patients were divided into two cohorts, local patients (from within Olmstead county and surrounding counties, 492 RSAs) and those from a distance (1,174 RSAs). RESULTS: Local patients were older (74 vs 71 years, p < .001), more likely to have RSA for fracture, had a higher Charlson comorbidity score (3.8 vs 3.2, p < .001) and longer hospital stays (2.0 vs 1.8 days, p < 0.001) compared to referred patients. Referral patients required longer operative times (95 vs 88 min, p = .002), had higher hospitalization costs ($19,101 vs $18,735, p < .001), and had a higher rate of prior surgery (32% vs 24%, p < .001). There were no differences between cohorts regarding complications or need for reoperation. CONCLUSIONS: Patients traveling from a distance to undergo primary RSA had longer operative times and were more likely to have had prior surgery than local patients. This may demonstrate the referral bias seen at large academic centers and should be considered when reviewing RSA outcomes, hospital performance, and calculating insurance reimbursement. LEVEL OF EVIDENCE: Level IV.

Anatomic total shoulder arthroplasty for primary glenohumeral osteoarthritis is associated with excellent outcomes and low revision rates in the elderly.

BACKGROUND: The relative indications of anatomic total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA) continue to evolve. Some surgeons favor RSA over TSA for elderly patients with primary glenohumeral osteoarthritis (GHOA) and an intact rotator cuff due to fear of a postoperative (secondary) rotator cuff tear in this age group. However, RSA is associated with unique complications and a worse functional arc of motion compared with TSA. Therefore, it is important to understand the clinical outcomes and rates of revision surgery and secondary rotator cuff tears in elderly patients undergoing TSA. METHODS: Between January 1, 2010, and December 31, 2017, 377 consecutive TSAs were performed for primary GHOA in 340 patients 70 years of age or older. The mean age at surgery was 76.2 years (standard deviation [SD], 4.9). Clinical evaluation included pain, motion, and American Shoulder and Elbow Surgeons score. Radiographs were reviewed for preoperative morphology and postoperative complications. All complications and reoperations were recorded. The average clinical follow-up time was 3.3 years (SD, 2.0). Statistical analyses were performed, and Kaplan-Meier implant survival estimates were calculated. For all analyses, a P value <.05 was considered statistically significant. RESULTS: The mean pain visual analog scale and American Shoulder and Elbow Surgeons score at the final follow-up were 1.6 (SD, 2.2) and 78.0 (SD, 17.8), respectively. Forward elevation and external rotation increased from 96° (SD, 30°) and 26° (SD, 20°) preoperatively to 160° (SD, 32°) and 64° (SD, 26°) postoperatively (P < .001 for each). The percentage of patients who had internal rotation to L5 or greater increased from 24.8% preoperatively to 71.8% postoperatively (P < .001). Revision surgery was performed in 3 shoulders (0.8%), and the 5-year implant survival estimate was 98.9% (95% confidence interval: 97.3%-100%). There were 3 medical (0.8%), 10 minor surgical (2.7%), and 5 major surgical (1.3%) complications. No shoulder had radiographic evidence of humeral component loosening, whereas 7 (2%) had evidence of some degree of glenoid component loosening. In total, there were 5 secondary rotator cuff tears (1.3%), of which 2 (0.5%) required revision surgery. CONCLUSION: Elderly patients with primary GHOA and an intact rotator cuff have excellent clinical and radiographic outcomes after anatomic TSA, with high implant survival rates and a low incidence of secondary rotator cuff tears in the first 5 postoperative years. Age greater than 70 by itself should not be considered an indication for RSA over TSA.

Biomechanical effectiveness of tendon transfers to restore active internal rotation in shoulder with deficient subscapularis with and without reverse shoulder arthroplasty.

BACKGROUND: Loss of active shoulder internal rotation can be very disabling. Several tendon transfers have been described for the management of an irreparable subscapularis (SSC) tear. The purpose of this study was to determine and compare the internal rotation moment arm (IRMA) of the sternal head of the pectoralis major (PM), latissimus dorsi (LD), and teres major (TM) when transferred to different insertion sites to restore shoulder internal rotation with and without reverse shoulder arthroplasty (RSA). METHODS: Six fresh-frozen right hemithoraces were prepared and evaluated using a custom tendon transfer model to determine the IRMA of different tendon transfers using the tendon and joint displacement method. Five tendon-transfer pairs were modeled using a single suture and tested before and after implantation of an RSA (Comprehensive; Zimmer-Biomet, Warsaw, IN, USA): PM to the insertion site of the SSC, LD to the anterior insertion site of the supraspinatus (SSP) tendon on the greater tuberosity, LD to SSC, TM to SSP, and TM to SSC. The SSC was not repaired at the end of the RSA procedure to simulate an SSC deficiency. The PM transfer was passed under the conjoined tendon when tested on the intact shoulder and above the conjoined tendon when tested with an RSA. RESULTS: Tendon transfers were shown to have a significant effect on IRMA. The effect of transferred tendons was significantly affected by the position of the humerus. With the humerus adducted, the IRMA of the TM-SSP (14.1 mm ± 3.1 mm) was significantly greater than the other transfers. With the humerus abducted to 90°, the IRMAs of the LD-SSP (30.0 mm ± 5.4 mm) and TM-SSP (28.4 mm ± 6.6 mm) were significantly greater than the IRMAs of other transfer options. The IRMA of the native shoulder differed significantly from that of the RSA state for all tendon transfers. With the humerus adducted to the side of the body, the IRMA of the RSA PM-SSC transfer was significantly greater than that without an RSA (19.0 mm ± 6.4 mm vs. 7.1 mm ± 0.9 mm), demonstrating increased efficiency for internal rotation in the RSA state. CONCLUSION: Tendon transfers to restore shoulder internal rotation differ in effectiveness and may be affected by arm position and by implantation of a lateralized humerus/lateralized glenoid RSA. The LD potentially results in superior restoration of shoulder internal rotation in a native shoulder (given the risk of nerve compression with the TM transfer) compared with PM and should be considered as a potential tendon transfer to restore internal rotation in selected patients. In combination with a lateralized humerus/lateralized glenoid RSA, the fulcrum provided by the biomechanics of the semiconstrained implant allows the PM transfer to become a more efficient tendon transfer to restore active internal rotation.

Shoulder arthroplasty in patients with juvenile idiopathic arthritis: long-term outcomes.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatologic disease that occurs in the pediatric population. Often, JIA continues throughout life, leading to progressive polyarticular arthritis and significant joint destruction and disability, oftentimes requiring replacement surgery. This study aimed to determine the outcomes of primary shoulder arthroplasty (SA) in patients with JIA. METHODS: Over a 42-year time period (1977-2019), 67 primary SA (20 hemiarthroplasty [HA], 38 anatomic total shoulder arthroplasty [TSA], and 9 reverse shoulder arthroplasty [RSA]) with a prior diagnosis of JIA formally established in a multidisciplinary rheumatologic clinic met inclusion criteria. Further assessment was performed with inclusion of the visual analog scale pain score, active shoulder range of motion (ROM), imaging studies, complications, and implant survivorship free from reoperation and revision. RESULTS: SA led to substantial improvements in pain and ROM across the entire cohort at an average follow-up period of 12.2 years (range, 2-34 years). TSA was associated with the lowest pain scores (0.8; P = .02) and the highest American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form scores (77.4; P = .04) at the most recent follow-up when compared to HA and RSA. There were 14 (21%) complications across the cohort with rotator cuff failure (n = 4; 5.9%) as the most common complication followed by infection (n = 3; 4.5%). Revision surgery was performed in 5 shoulders (7.5%), with 5-year implant survival rates of 95.1% at 5 years, 93% at 10 years, 89.4% at 20 years, and 79.5% at 30 years. At 30 years, TSA was associated with better survival (90.1%) than HA (71.8%). CONCLUSIONS: Primary shoulder arthroplasty in the form of HA, TSA, and RSA offers a reliable surgical option for JIA patients with respect to pain reduction and ROM improvements. Unique challenges still exist in this cohort, in particular younger patients with an elevated propensity for glenoid bone erosion and a complication rate of 20.9%. As such, HA may not be ideal in this patient population. However, despite rotator cuff and glenoid concerns, TSA seems to be associated with better pain relief and patient-reported outcomes with the most durability in the long term when compared to HA.

Shoulder arthroplasty is a viable option in patients with Ehlers-Danlos syndrome.

BACKGROUND: Patients with Ehlers-Danlos syndrome (EDS) have high rates of shoulder instability, which place them at increased risk for instability-related arthropathy. Many studies have assessed outcomes for both primary and revision shoulder instability procedures in this patient population, but there is a paucity of data regarding the outcome of shoulder arthroplasty in EDS patients. The purpose of this study is to evaluate the results and complications of shoulder arthroplasty (SA) performed in a cohort of patients with EDS and compare them to a matched cohort of patients with no EDS. METHODS: Over an 11-year period, 10 patients with EDS were identified at a single institution who underwent primary SA (6 anatomic total shoulder arthroplasties [aTSAs], 4 reverse shoulder arthroplasties [RTSAs]). Shoulders were evaluated at a mean follow-up of 60 months (range 25-97 months). This cohort was matched 1:2 based on age, sex, and year of surgery, with patients who underwent SA for either primary osteoarthritis (OA) for aTSA or cuff tear arthropathy for RTSA. EDS patients had a mean age of 55 years, mean body mass index of 26.1, and were all female. The primary outcome measures were postoperative pain, range of motion, complications, and reoperations. RESULTS: SA produced similar postoperative pain, range of motion, complications, and reoperations in patients with EDS vs. controls. EDS patients improved pre- to postoperative visual analog scale (VAS) pain score (6.5 to 1.7, P < .001), elevation (96° to 138°, P = .04), and external rotation (36° to 57°, P = .16). Three EDS patients sustained postoperative complications (2 instability and 1 acromial fracture); however, no shoulder was reoperated. CONCLUSIONS: EDS patients undergoing SA can expect outcomes comparable to patients with primary OA or cuff tear arthropathy, with clinically meaningful improvements in pain and range of motion. Although EDS patients had no statistically significant increase in complications when compared to controls, their absolute rate of overall complications (3/10 patients; 30%) and postoperative instability (2/10 patients; 20%) in this small case series was relatively high and should be considered when performing SA.

Primary reverse shoulder arthroplasty in patients with metabolic syndrome is associated with increased rates of deep infection.

BACKGROUND: Metabolic syndrome (MetS) is an abnormal physiological condition that has been increasingly identified as a risk factor for complications after orthopedic surgery. Given the lack of information on the effect of MetS in shoulder arthroplasty (SA), this investigation analyzed the rates of postoperative complications and implant survivorship free from reoperation and revision in patients with and without MetS. METHODS: Between 2007 and 2017, data from 4635 adults who underwent a primary SA were collected and classified based on the presence or absence of MetS. MetS was defined as the existence of type 2 diabetes mellitus and a minimum of 2 of the following diagnoses: hyperlipidemia, hypertension, and body mass index ≥ 30 kg/m2 within 1 year of surgery. Of the 4635 arthroplasties, 714 were performed in patients with MetS (anatomic total shoulder arthroplasty [aTSA] in 289 and reverse shoulder arthroplasty [RSA] in 425) and 3921 were performed in patients without MetS (aTSA in 1736 and RSA in 2185). Demographic characteristics, complications, reoperations, and revision surgery were compared. RESULTS: At a mean of follow-up of 4.5 ± 2.3 years, 67 MetS patients (9.4%) and 343 non-MetS patients (8.7%) had sustained at least 1 postoperative complication (P = .851). Rotator cuff failure was the most common complication overall, with 84 cases (1.8%) (15 MetS cases [2.1%] and 69 non-MetS cases [1.8%], P = .851), and in both MetS and non-MetS patients, followed by infection, with 68 cases (1.2%) (10 MetS cases [1.4%] and 58 non-MetS cases [1.2%], P = .913). For aTSAs, the most common complication was rotator cuff failure (84 shoulders, 1.8%); for RSAs, the most common complication was periprosthetic fracture (52 shoulders, 1.1%). In RSAs, the rates of deep infection (1.9% vs. 0.7%, P = .04), instability (3.1% vs. 1.5%, P = .04), and deep venous thrombosis or pulmonary embolism (0.5% vs. 0.3%, P = .03) were found to be significantly higher in patients with MetS than in those without MetS. Reoperations were observed in 36 MetS patients (5%) and 170 non-MetS patients (4.3%) (P = .4). Revisions were performed in 30 MetS patients (4.2%) and 127 non-MetS patients (3.2%) (P = .19). The Kaplan-Meier 5-year rate of survivorship free from reoperation, revision, and prosthetic joint infection was equal between groups. CONCLUSIONS: A preoperative diagnosis of MetS in patients undergoing primary SA did not significantly increase the risk of postoperative complications, infection, reoperation, or revision following primary SA. However, in the RSA subgroup, complications were significantly more common in patients with MetS. Individual risk factors may be more appropriate than the umbrella diagnosis of MetS prior to aTSA.

Shoulder arthroplasty in patients with immunosuppression following solid organ transplantation.

BACKGROUND: The purpose was to determine the risk and outcomes of primary shoulder arthroplasties in patients with immunosuppression who had undergone solid organ transplantation. METHODS: Using a single institution's total joint registry, we reviewed 30 primary shoulder arthroplasties in 25 post-transplantation patients, including 12 total shoulder arthroplasties, 10 hemiarthroplasties, and 8 reverse shoulder arthroplasties, between 1985 and 2012. Therapy and patient variables were recorded, including immunosuppressive therapy protocols, the date of preceding solid organ transplantation, and specific medications taken in the perioperative period. We matched a cohort of control patients for age, sex, type of implant, and year of surgery at a ratio of 4:1. Two groups were compared regarding mortality risk, complications, and clinical outcomes (pain score, range of motion, and American Shoulder and Elbow Surgeons score). RESULTS: No periprosthetic infections occurred in the post-transplantation group at a mean follow-up of 39 months. However, the post-transplantation group showed an increased risk of periprosthetic fractures compared with the control group (hazard ratio, 8.18; 95% confidence interval, 1.22-70.98; P = .03). Despite the increase in fractures, the overall number of complications did not differ between the groups. Furthermore, postoperative shoulder function and outcome scores were not significantly different between patients who had a prior transplant and those who did not. CONCLUSION: Primary shoulder arthroplasty in patients with immunosuppression who underwent solid organ transplantation is a successful procedure to treat glenohumeral arthritis. In contrast, there may be an increased risk of periprosthetic fractures in patients with a history of a solid organ transplant.

The effect of patient-reported metal allergies on the outcomes of shoulder arthroplasty.

BACKGROUND: Although literature exists regarding hip and knee arthroplasty outcomes in patients with skin allergy to metals, there is minimal information about skin allergy implications on shoulder arthroplasty outcomes. The purpose of this study was to determine the results, complications, and failure rate among patients with a self-reported metal allergy undergoing shoulder arthroplasty. METHODS: Fifty-two shoulder arthroplasties were performed at our Institution in 43 patients with self-reported metal allergies. Forty primary and 12 revision shoulder arthroplasties were performed using anatomic (30) and reverse (22) components. Retrospective chart review was performed to determine metal allergy history, implant composition, pain, motion, and complications. Radiographs were reviewed to determine mechanical failure rates. Average follow-up time was 65 months. RESULTS: Allergies reported included nickel (37), cobalt chrome (4), copper (2), zinc (1), titanium (1), gold (1), and nonspecific metal allergy (8); 8 patients reported multiple metal allergies. All components implanted in patients with nickel allergies contained nickel. At most recent follow-up, pain was rated as none or mild in 88% of shoulders. Active elevation improved from 80° to 141° and external rotation from 24° to 52°. Two revisions were performed for glenoid loosening (3.8%); both were revision cases with substantial glenoid bone loss. One patient with mild pain had a radiographically loose glenoid component 12 years after anatomic shoulder arthroplasty. CONCLUSION: Results from this study suggest that shoulder arthroplasty in patients with self-reported metal allergy provides satisfactory pain relief and improved range of motion with low revision rates.

Shoulder arthroplasty in patients with cerebral palsy: a matched cohort study to patients with osteoarthritis.

BACKGROUND: Patients with cerebral palsy (CP) often experience shoulder impairment via spasticity, muscle contractures, and joint instability. Currently, few studies investigate shoulder arthroplasty (SA) in patients with CP. This study reviewed the outcomes of both anatomic total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RSA) in patients with CP. METHODS: Over a 30-year-period, 5 patients undergoing SA (2 TSA, 3 RSA) with a diagnosis of CP were identified. The cohort included 4 male patients with a mean age of 50.4 years (range, 44-58 years). CP patients were matched 1:2 based on age, sex, body mass index, and year of surgery with a group of patients undergoing SA for osteoarthritis (OA). RESULTS: Survival from implant revision for both TSA and RSA in CP was 100% at both 2 and 5 years postoperatively. Clinical complications were only observed in 2 patients after TSA, with 1 patient requiring revision at 14 years postoperatively. Collectively, there was no difference in the rate of complications and implant survival between patients with CP vs. OA. Prior to the surgical procedure, all CP patients had severe or moderate pain, with no moderate or severe pain postoperatively. Notable postoperative increases from preoperative baselines were noted in forward elevation (57°-106°), abduction (48°-84°), and external rotation (30°-64°). RSA had significantly improved postoperative abduction compared to TSA (97° vs. 64°, P < .01). CONCLUSIONS: SA is a safe, durable procedure in patients with CP to clinically improve pain, function, and satisfaction. RSA was associated with better function and fewer complications than TSA.