Lower Trapezius Transfer Improves Clinical Outcomes With a Rate of Complications and Reoperations Comparable to Other Surgical Alternatives in Patients with Functionally Irreparable Rotator Cuff Tears: A Systematic Review.

PURPOSE: To analyze the clinical outcomes of lower trapezius transfer (LTT) for patients with functionally irreparable rotator cuff tears (FIRCT) and summarize the available literature regarding complications and reoperations. METHODS: After registration in the International prospective register of systematic reviews (PROSPERO [CRD42022359277]), a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. Inclusion criteria were English, full-length, peer-reviewed publications with a level of evidence IV or higher reporting on clinical outcomes of LTT for FIRCT. Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus via Elsevier databases were searched. Clinical data, complications and revisions were systematically recorded. RESULTS: Seven studies with 159 patients were identified. The mean age range was 52 to 63 years, 70.4% of the patients included were male, and the mean follow-up time ranged between 14 and 47 months. At final follow-up, LTT lead to improvements in range of motion, with reported forward elevation (FE) and external rotation (ER) mean gains of 10° to 66° and 11° to 63°, respectively. ER lag was present before surgery in 78 patients and was reversed after LTT in all shoulders. Patient-reported outcomes were improved at final follow-up, including the American Shoulder and Elbow Society score, Shoulder Subjective Value and Visual Analogue Scale. The overall complication rate was 17.6%, and the most reported complication was posterior harvest site seroma/hematoma (6.3%). The most common reoperation was conversion to reverse shoulder arthroplasty (5%) with an overall reoperation rate of 7.5%. CONCLUSIONS: Lower trapezius transfer improves clinical outcomes in patients with irreparable rotator cuff tears with a rate of complications and reoperations comparable to other surgical alternatives in this group of patients. Increases in forward flexion and ER are to be expected, as well as a reversal of ER lag sign when present before surgery. LEVEL OF EVIDENCE: Level IV, systematic review of Level III-IV studies.

Deep learning to automatically classify very large sets of preoperative and postoperative shoulder arthroplasty radiographs.

BACKGROUND: Joint arthroplasty registries usually lack information on medical imaging owing to the laborious process of observing and recording, as well as the lack of standard methods to transfer the imaging information to the registries, which can limit the investigation of various research questions. Artificial intelligence (AI) algorithms can automate imaging-feature identification with high accuracy and efficiency. With the purpose of enriching shoulder arthroplasty registries with organized imaging information, it was hypothesized that an automated AI algorithm could be developed to classify and organize preoperative and postoperative radiographs from shoulder arthroplasty patients according to laterality, radiographic projection, and implant type. METHODS: This study used a cohort of 2303 shoulder radiographs from 1724 shoulder arthroplasty patients. Two observers manually labeled all radiographs according to (1) laterality (left or right), (2) projection (anteroposterior, axillary, or lateral), and (3) whether the radiograph was a preoperative radiograph or showed an anatomic total shoulder arthroplasty or a reverse shoulder arthroplasty. All these labeled radiographs were randomly split into developmental and testing sets at the patient level and based on stratification. By use of 10-fold cross-validation, a 3-task deep-learning algorithm was trained on the developmental set to classify the 3 aforementioned characteristics. The trained algorithm was then evaluated on the testing set using quantitative metrics and visual evaluation techniques. RESULTS: The trained algorithm perfectly classified laterality (F1 scores [harmonic mean values of precision and sensitivity] of 100% on the testing set). When classifying the imaging projection, the algorithm achieved F1 scores of 99.2%, 100%, and 100% on anteroposterior, axillary, and lateral views, respectively. When classifying the implant type, the model achieved F1 scores of 100%, 95.2%, and 100% on preoperative radiographs, anatomic total shoulder arthroplasty radiographs, and reverse shoulder arthroplasty radiographs, respectively. Visual evaluation using integrated maps showed that the algorithm focused on the relevant patient body and prosthesis parts for classification. It took the algorithm 20.3 seconds to analyze 502 images. CONCLUSIONS: We developed an efficient, accurate, and reliable AI algorithm to automatically identify key imaging features of laterality, imaging view, and implant type in shoulder radiographs. This algorithm represents the first step to automatically classify and organize shoulder radiographs on a large scale in very little time, which will profoundly enrich shoulder arthroplasty registries.

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.

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.

Operative Treatment of Acromial and Scapular Spine Fracture Nonunions Complicating Reverse Total Shoulder Arthroplasty.

BACKGROUND: Fractures of the acromion and spine can have a major impact on the outcome of reverse shoulder arthroplasty (RSA) with respect to pain, motion, and function. Reports on internal fixation for these fractures are isolated to small series or case reports with variable outcomes. The purpose of this study was to report on the outcome of open reduction and internal fixation (ORIF) of acromion or spine fractures encountered before or after RSA and describe our evolution of fixation techniques. METHODS: Between 2011 and 2023, 22 fractures or nonunions of the acromion or spine of the scapula underwent ORIF at a single institution and were followed for a minimum of 1 year. In 16 shoulders, fractures occurred after RSA, whereas 5 shoulders underwent ORIF prior to RSA. One shoulder had undergone prior failed ORIF elsewhere and revision ORIF was performed at our institution. There were 10 males and 12 females with a mean age of 67 (SD=15.1) years. Fixation strategies included single (n=11) and double plate fixation (n=11). Kruskal-Wallis one-way analyses of variance were used to analyze continuous variables and Chi-square tests employed for categorical variables. RESULTS: Of the 5 fractures treated with ORIF pre-RSA, 1 shoulder suffered an additional fracture medial to the hardware and 1 required additional bone grafting for incomplete union at the time of RSA. These 5 shoulders all underwent RSA uneventfully, but one fracture experienced late displacement of the scapular spine nonunion, leading to plate removal. Of the 16 post-RSA ORIF shoulders, radiographic union was confirmed in 14 and substantial residual inferior angulation identified in 3. New fractures occurred after ORIF in 5 shoulders. For patients who underwent ORIF after RSA, pain scores improved from a mean of 8 to 1.9 points, with more modest elevation gains (58.2° to 91.3° pre- and postoperatively, respectively). CONCLUSIONS: ORIF of acromion and scapular spine fractures or nonunions in the setting of RSA have the potential to lead to union. When these fractures and nonunions are encountered prior to RSA, ORIF allows for uneventful RSA implantation, but secondary displacement may occur. ORIF seems to lead to improvements in pain, but more modest improvements in motion and function. Our fixation strategy has evolved to (1) dual plating, (2) spanning the whole length of the spine with one of the plates, (3) use of hook features under the acromion or os trigonum if possible, and (4) liberal use of bone graft.

Non-cefazolin antibiotic prophylaxis is associated with higher rates of elbow periprosthetic joint infection.

BACKGROUND: Periprosthetic joint infection (PJI) is a common source of failure following elbow arthroplasty. Perioperative prophylactic antibiotics are considered standard of care. However, there are no data regarding the comparative efficacy of various antibiotics in the prevention of PJI for elbow arthroplasty. Previous studies in shoulder, hip, and knee arthroplasty have demonstrated higher rates of PJI with administration of non-cefazolin antibiotics. The elbow has higher rates of PJI than other joints. Therefore, this study evaluated whether perioperative antibiotic choice affects rates of PJI in elbow arthroplasty. MATERIALS AND METHODS: A single-institution, prospectively collected total joint registry database was queried to identify patients who underwent primary elbow arthroplasty between 2003 and 2021. Elbows with known infection prior to arthroplasty (25) and procedures with incomplete perioperative antibiotic data (7) were excluded, for a final sample size of 603 total elbow arthroplasties and 19 distal humerus hemiarthroplasties. Cefazolin was administered in 561 elbows (90%) and non-cefazolin antibiotics including vancomycin (32 elbows, 5%), clindamycin (27 elbows, 4%), and piperacillin/tazobactam (2 elbows, 0.3%) were administered in the remaining 61 elbows (10%). Univariate and multivariate analyses were conducted to determine the association between the antibiotic administered and the development of PJI. Infection-free survivorship was estimated using the Kaplan-Meier method. RESULTS: Deep infection occurred in 47 elbows (7.5%), and 16 elbows (2.5%) were diagnosed with superficial infections. Univariate analysis demonstrated that patients receiving non-cefazolin alternatives were at significantly higher risk for any infection (hazard ratio [HR] 2.6, 95% confidence interval [CI] 1.4-5.0; P < .01) and deep infection (HR 2.7, 95% CI 1.3-5.5; P < .01) compared with cefazolin administration. Multivariable analysis, controlling for several independent predictors of PJI (tobacco use, male sex, surgical indication other than osteoarthritis, and American Society of Anesthesiologists score), showed that non-cefazolin administration had a higher risk for any infection (HR 2.8, 95% CI 1.4-5.3; P < .01) and deep infection (HR 2.9, 95% CI 1.3-6.3; P < .01). Survivorship free of infection was significantly higher at all time points for the cefazolin cohort. DISCUSSION: In primary elbow arthroplasty, cefazolin administration was associated with significantly lower rates of PJI compared to non-cefazolin antibiotics, even in patients with a greater number of prior surgeries, which is known to increase the risk of PJI. For patients with penicillin or cephalosporin allergies, preoperative allergy testing or a cefazolin test dose should be considered before administering non-cefazolin alternatives.

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.

Platelet-Rich Plasma and Marrow Venting May Serve as Cost-Effective Augmentation Techniques for Isolated Meniscal Repair: A Decision-Analytical Markov Model-Based Analysis.

PURPOSE: To evaluate the cost-effectiveness of 3 isolated meniscal repair (IMR) treatment strategies: platelet-rich plasma (PRP)-augmented IMR, IMR with a marrow venting procedure (MVP), and IMR without biological augmentation. METHODS: A Markov model was developed to evaluate the baseline case: a young adult patient meeting the indications for IMR. Health utility values, failure rates, and transition probabilities were derived from the published literature. Costs were determined based on the typical patient undergoing IMR at an outpatient surgery center. Outcome measures included costs, quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio (ICER). RESULTS: Total costs of IMR with an MVP were $8,250; PRP-augmented IMR, $12,031; and IMR without PRP or an MVP, $13,326. PRP-augmented IMR resulted in an additional 2.16 QALYs, whereas IMR with an MVP produced slightly fewer QALYs, at 2.13. Non-augmented repair produced a modeled gain of 2.02 QALYs. The ICER comparing PRP-augmented IMR versus MVP-augmented IMR was $161,742/QALY, which fell well above the $50,000 willingness-to-pay threshold. CONCLUSIONS: IMR with biological augmentation (MVP or PRP) resulted in a higher number of QALYs and lower costs than non-augmented IMR, suggesting that biological augmentation is cost-effective. Total costs of IMR with an MVP were significantly lower than those of PRP-augmented IMR, whereas the number of additional QALYs produced by PRP-augmented IMR was only slightly higher than that produced by IMR with an MVP. As a result, neither treatment dominated over the other. However, because the ICER of PRP-augmented IMR fell well above the $50,000 willingness-to-pay threshold, IMR with an MVP was determined to be the overall cost-effective treatment strategy in the setting of young adult patients with isolated meniscal tears. LEVEL OF EVIDENCE: Level III, economic and decision analysis.

Improved Yet Varied Clinical Outcomes Observed With Comparison of Arthroscopic Superior Capsular Reconstruction Versus Arthroscopy-Assisted Lower Trapezius Transfer for Patients With Irreparable Rotator Cuff Tears.

PURPOSE: To evaluate the outcomes of arthroscopic superior capsular reconstruction (SCR) and arthroscopy-assisted lower trapezius tendon transfer (LTT) for posterosuperior irreparable rotator cuff tears (IRCTs). METHODS: Over an almost 6-year period (October 2015 to March 2021), all patients who underwent IRCT surgery with a minimum 12-month follow-up period were identified. For patients with a substantial active external rotation (ER) deficit or lag sign, LTT was preferentially selected. Patient-reported outcome scores included the visual analog scale (VAS) pain score, strength score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, Single Assessment Numeric Evaluation (SANE) score, and Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score. RESULTS: We included 32 SCR patients and 72 LTT patients. Preoperatively, LTT patients had more advanced teres minor fatty infiltration (0.3 vs 1.1, P = .009), a higher global fatty infiltration index (1.5 vs 1.9, P = .035), and a higher presence of the ER lag sign (15.6% vs 48.6%, P < .001). At a mean follow-up of 2.9 ± 1.3 years (range, 1.0-6.3 years), no differences in patient-reported outcome scores were observed. Postoperatively, SCR patients had a lower VAS score (0.3 vs 1.1, P = .017), higher forward elevation (FE) (156° vs 143°, P = .004), and higher FE strength (4.8 vs 4.5, P = .005) and showed greater improvements in the VAS score (6.8 vs 5.1, P = .009), FE (56° vs 31°, P = .004), and FE strength (1.0 vs 0.4, P < .001). LTT patients showed greater improvement in ER (17° vs 29°, P = .026). There was no statistically significant between-cohort difference in complication rate (9.4% vs 12.5%, P = .645) or reoperation rate (3.1% vs 10%, P = .231). CONCLUSIONS: With adequate selection criteria, both SCR and LTT provided improved clinical outcomes for posterosuperior IRCTs. Additionally, SCR led to better pain relief and restoration of FE whereas LTT provided more reliable improvement in ER. LEVEL OF EVIDENCE: Level III, treatment study with retrospective cohort comparison.

Choosing the appropriate measure of central tendency: mean, median, or mode?

Mean, median, and mode are among the most basic and consistently used measures of central tendency in statistical analysis and are crucial for simplifying data sets to a single value. However, there is a lack of understanding of when to use each metric and how various factors can impact these values. The aim of this article is to clarify some of the confusion related to each measure and explain how to select the appropriate metric for a given data set. The authors present this work as an educational resource, ensuring that these common statistical concepts are better understood throughout the Orthopedic research community.

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.

Do patients with poor early clinical outcomes after reverse total shoulder arthroplasty ultimately improve?

BACKGROUND: Although most patients undergoing reverse total shoulder arthroplasty (rTSA) have substantial improvement in pain and function at early follow-up, improvements in pain and range of motion progress more slowly during postoperative rehabilitation in a subset of patients. The purpose of this study was to define a patient's risk of persistent shoulder dysfunction beyond the early postoperative period and identify risk factors for persistent poor performance. METHODS: We retrospectively reviewed 292 primary rTSAs with early poor performance and a preoperative diagnosis of osteoarthritis, cuff tear arthropathy, or rotator cuff tear from a multicenter database. Early poor performance was defined as a postoperative American Shoulder and Elbow Surgeons (ASES) score below the 20th percentile at 3 months (58 points) or 6 months (65 points) postoperatively. Persistent poor performance at 2 years was defined as failure to achieve the patient acceptable symptomatic state for rTSA (77.3 points for the ASES score). The primary outcome was the rate of persistent poor performance. Secondarily, we compared the clinical outcomes of persistent poor performers vs. shoulders that improved at 2-year follow-up and assessed risk factors for persistent poor performance. RESULTS: At 2-year follow-up, 61% of patients (n = 178) with poor performance at either 3- or 6-month follow-up had persistent poor performance. The rate increased to 85% if poor performance occurred at both 3- and 6-month follow-up. The minimal clinically important difference and substantial clinical benefit for range of motion and outcome scores were exceeded by early poor performers at rates of 83%-92% and 60%-77%, respectively, at 2-year follow-up. On multivariate logistic regression analysis, independent predictors of persistent poor performance after rTSA were lack of hypertension (odds ratio [OR], 0.27; 95% confidence interval [CI], 0.13-0.57; P < .001), heart disease (OR, 2.89; 95% CI, 1.24-6.77; P = .011), uncemented humeral fixation (OR, 0.11; 95% CI, 0.01-1.18; P = .037), previous shoulder surgery (OR, 2.14; 95% CI, 1.06-4.30; P = .031), lower preoperative ASES score (OR, 0.92; 95% CI, 0.87-0.97; P = .002), and lower preoperative subjective rating of pain at its worst (OR, 0.73; 95% CI, 0.54-0.99; P = .038). DISCUSSION: Despite the fact that 85% of rTSA patients with an ASES score below the 20th percentile at early follow-up exceeded the minimal clinically important difference for improvement in the ASES score at 2-year clinical follow-up, 61% still had persistent poor performance, with failure to achieve the patient acceptable symptomatic state for the ASES score. Persistent poor performance after rTSA was best predicted by a history of shoulder surgery and a poorer preoperative ASES score. These findings can aid surgeons when counseling patients both preoperatively and postoperatively. In the setting of early poor performance, the risk of persistent poor performance must be balanced against the potential outcomes of revision surgery when considering early surgical intervention.

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.

Understanding risk for early dislocation resulting in reoperation within 90 days of reverse total shoulder arthroplasty: extreme rare event detection through cost-sensitive machine learning.

BACKGROUND: Reliable prediction of postoperative dislocation after reverse total shoulder arthroplasty (RSA) would inform patient counseling as well as surgical and postoperative decision making. Understanding interactions between multiple risk factors is important to identify those patients most at risk of this rare but costly complication. To better understand these interactions, a game theory-based approach was undertaken to develop machine learning models capable of predicting dislocation-related 90-day readmission following RSA. MATERIAL & METHODS: A retrospective review of the Nationwide Readmissions Database was performed to identify patients who underwent RSA between 2016 and 2018 with a subsequent readmission for prosthetic dislocation. Of the 74,697 index procedures included in the data set, 740 (1%) experienced a dislocation resulting in hospital readmission within 90 days. Five machine learning algorithms were evaluated for their ability to predict dislocation leading to hospital readmission within 90 days of RSA. Shapley additive explanation (SHAP) values were calculated for the top-performing models to quantify the importance of features and understand variable interaction effects, with hierarchical clustering used to identify cohorts of patients with similar risk factor combinations. RESULTS: Of the 5 models evaluated, the extreme gradient boosting algorithm was the most reliable in predicting dislocation (C statistic = 0.71, F2 score = 0.07, recall = 0.84, Brier score = 0.21). SHAP value analysis revealed multifactorial explanations for dislocation risk, with presence of a preoperative humerus fracture; disposition involving discharge or transfer to a skilled nursing facility, intermediate care facility, or other nonroutine facility; and Medicaid as the expected primary payer resulting in strong, positive, and unidirectional effects on increasing dislocation risk. In contrast, factors such as comorbidity burden, index procedure complexity and duration, age, sex, and presence or absence of preoperative glenohumeral osteoarthritis displayed bidirectional influences on risk, indicating potential protective effects for these variables and opportunities for risk mitigation. Hierarchical clustering using SHAP values identified patients with similar risk factor combinations. CONCLUSION: Machine learning can reliably predict patients at risk for postoperative dislocation resulting in hospital readmission within 90 days of RSA. Although individual risk for dislocation varies significantly based on unique combinations of patient characteristics, SHAP analysis revealed a particularly at-risk cohort consisting of young, male patients with high comorbidity burdens who are indicated for RSA after a humerus fracture. These patients may require additional modifications in postoperative activity, physical therapy, and counseling on risk-reducing measures to prevent early dislocation after RSA.

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.

Patients with poor early clinical outcomes after anatomic total shoulder arthroplasty have sustained poor performance at 2 years from surgery.

PURPOSE: We sought to define the risk of persistent shoulder dysfunction after anatomic total shoulder arthroplasty (aTSA) beyond the early postoperative period and identify risk factors for persistent poor performance. METHODS: We retrospectively identified 144 primary aTSAs performed for primary osteoarthritis with early poor performance and 2-year minimum follow-up. Early poor performance was defined as a postoperative ASES score below the 20th percentile at 3- or 6-months (62 and 72 points, respectively). Persistent poor performance at 2 years was defined as failing to achieve the patient acceptable symptomatic state (PASS) [ASES = 81.7 points]. RESULTS: At 2-year follow-up, 51% (n = 74) of patients with early poor performance at either 3- or 6-month follow-up had persistent poor performance. There was no difference in the rate of persistent poor performance if patients were poor performers at the 3-, 6-month follow-up, or both (50% vs. 49% vs. 56%, P = .795). Of aTSAs achieving the PASS at 2-year follow-up, a greater proportion exceeded the minimal clinically important differences (MCID) [Forward elevation, external rotation, and all outcome scores] and substantial clinical benefit (SCB) [external rotation and all outcome scores] compared to persistent poor performers. However, over half of persistent poor performers still exceeded the MCID for all outcome measures (56-85%). Independent predictors of persistent poor performance were hypertension (2.61 [1.01-6.72], P = .044) and diabetes (5.14 [1.00-26.4], P = .039). CONCLUSION: Over half of aTSAs with an ASES score < 20th percentile at early follow-up had continued poor shoulder function at 2-years postoperatively. Persistent poor performance was best projected by preoperative hypertension and diabetes. LEVEL OF EVIDENCE: Level III; Retrospective Cohort Comparison using Large Database; Treatment Study.

Shoulder arthroplasty after prior anterior shoulder instability surgery: a matched cohort analysis.

PURPOSE: To evaluate the effect of prior anterior shoulder instability surgery (SIS) on the outcomes and complications of primary anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA). METHODS: Between 2007 and 2018, 38 primary total shoulder arthroplasties (TSA) (22 aTSA and 16 rTSA) with a prior SIS and a minimum of 2 years of follow-up were identified. This cohort was matched 1:3 based on age, sex, body mass index, year of surgery, and dominant shoulder. aTSA and rTSA were matched to patients with primary osteoarthritis (OA) and rotator cuff tear arthropathy (CTA), respectively. RESULTS: TSA produced similar postoperative pain, ROM, patient-reported outcome measures, complications, and revisions in those with prior SIS vs. controls. aTSA with prior SIS demonstrated worse final postoperative abduction (116° vs. 133°; P = 0.046) and abduction improvement (24° vs. 47°; P = 0.034) compared to OA controls. Both aTSA and rTSA with prior SIS demonstrated significant improvements from baseline across all metrics, with no significant differences between the groups. aTSA and rTSA with prior SIS demonstrated no differences to controls in complications (4.6% vs. 6.1%; P = .786 and 0% vs. 6.3%. P = .183) or revisions (4.6% vs. 4.6%; P = .999 and 0% vs. 4.2%; P = .279). CONCLUSIONS: TSA after prior SIS surgery can improve both pain and function without adversely increasing the rates of complications or revision surgery. When compared to patients without prior SIS, aTSA demonstrated worse abduction; however, all other functional differences remained statistically similar. LEVEL OF EVIDENCE: III; Retrospective Cohort Comparison; Treatment Study.