What factors can reduce the need for repeated revision for humeral loosening in revision total elbow arthroplasty?

BACKGROUND: This study aimed to determine the re-revision rate in a cohort of patients who underwent revision total elbow arthroplasty (rTEA) for humeral loosening (HL) and identify factors contributing to re-revision. We hypothesized that proportional increases in the stem and flange lengths would stabilize the bone-implant interface significantly more than a disproportional increase in stem or flange length alone. Additionally, we hypothesized that the indication for the index arthroplasty would impact the need for repeated revision for HL. The secondary objective was to describe the functional outcomes, complications, and presence of radiographic loosening after rTEA. METHODS: We retrospectively reviewed 181 rTEAs performed from 2000-2021. We included 40 rTEAs for HL performed on 40 elbows that either required a subsequent revision for HL (10 rTEAs) or had a minimum of 2 years of clinical or radiographic follow-up. One hundred thirty-one cases were excluded. Patients were grouped based on stem and flange length to determine the re-revision rate. Patients were divided based on re-revision status into the single-revision group and the re-revision group. The stem-to-flange length (S/F) ratio was calculated for each surgical procedure. The mean length of clinical and radiographic follow-up was 71 months (range, 18-221 months and 3-221 months, respectively). RESULTS: Rheumatoid arthritis was statistically significant in predicting re-revision total elbow arthroplasty for HL (P = .024). The overall re-revision rate for HL was 25% at an average of 4.2 years (range, 1-19 years) from the revision procedure. There was a significant increase in stem and flange lengths from the index procedure to revision, on average by 70 ± 47 mm (P < .001) and 28 ± 39 mm (P < .001), respectively. In the cases of re-revision (n = 10), 4 patients underwent an excisional procedure; in the remaining 6 cases, the size of the re-revision implant increased on average by 37 ± 40 mm for the stem and 73 ± 70 mm for the flange (P = .075 and P = .046, respectively). Furthermore, the average flange in these 6 cases was 7 times shorter than the average stem (S/F ratio, 6.7 ± 2.2). This ratio was significantly different from that in cases that were not re-revised (P = .03; S/F ratio, 4.2 ± 2). Mean range of moion was 16° (range, 0°-90°; standard deviation, 20°) extension to 119° (range, 0°-160°; standard deviation, 39°) flexion at final follow-up. Complications included ulnar neuropathy (38%), radial neuropathy (10%), infection (14%), ulnar loosening (14%), and fracture (14%). None of the elbows were considered radiographically loose at final follow-up. CONCLUSION: We show that a primary diagnosis of rheumatoid arthritis and a humeral stem with a relatively short flange relative to the stem length significantly contribute to re-revision of total elbow arthroplasty. The use of an implant where the flange can be extended beyond one-fourth of the stem length may increase implant longevity.

Updating insights into the rehydration of dairy-based powder and the achievement of functionality.

Dairy-based powder had considerable development in the recent decade. Meanwhile, the increased variety of dairy-based powder led to the complex difficulties of rehydrating dairy-based powder, which could be the poor wetting or dissolution of powder. To solve these various difficulties, previous studies investigated the rehydration of powder by mechanical and chemical methods on facilitating rehydration, while strategies were designed to improve the rate-limiting rehydration steps of different powder. In this review, special emphasis is paid to the surface and structure of the dairy-based powder, which was accountable for understanding rehydration and the rate-limiting step. Besides, the advantage and disadvantage of methods employed in rehydration were described and compared. The achievement of the powder functionality was finally discussed and correlated with the rehydration methods. It was found that the surface and structure of dairy-based powder were decided by the components and production of powder. Post-drying methods like agglomeration and coating can tailor the surface and structure of powder afterwards to obtain better rehydration. The merit of the mechanical method is that it can be applied to rehydrate dairy-based powder without any addition of chemicals. Regarding chemical methods, calcium chelation is proved to be an effective chemical in rehydration casein-based powder.

Investigation of breakage behavior and its effects on spray-dried agglomerated whey protein-lactose powders: Effect of protein and lactose contents.

Particle breakage of dairy powders occurs easily during many processes, reducing the powder functionality. The characteristics of particles and the applied stress from processing conditions on the particles are 2 main factors that can be manipulated to reduce breakage. In this study, we explored the effect of whey protein and lactose contents on dynamic breakage in agglomerated whey protein-lactose powders to provide useful information, in terms of particle characteristics, for controlling unwanted dairy powder breakage. A series of model agglomerates with different whey protein:lactose ratios were produced under the same spray-drying conditions, through a pilot plant trial. We evaluated physical characteristics, composition, and structure of samples; analyzed dynamic breakage under different mechanical stresses; and investigated the rehydration and water adsorption properties of model powders before and after breakage. The particle size and irregularity of agglomerates with more lactose was significantly higher than of samples that contained more protein. This resulted in higher particle breakage during dynamic breakage for samples with more lactose. The breakage of agglomerates was affected by the moisture content of powders and fatigue, where particle breakage happens when mechanical loads, lower than the strength of particles, occur multiple times. Breakage changed the morphology and surface composition of particles and decreased particle size. It also decreased the dispersibility of powders and increased the wetting time of wettable samples but decreased the wetting time of powders with poor wettability. Breakage accelerated time-dependent crystallization and decreased the crystallization temperature but did not affect the glass transition temperature of samples. Thus, under the same drying conditions, composition of powders significantly affected breakage, mainly by altering the physical properties of their particles, which resulted in deteriorated functionality.

Semi-automated Tracing of Hamstring Muscle Architecture for B-mode Ultrasound Images.

Hamstring strains are the most prevalent injury sustained by field-sport athletes. Insufficiencies in the architectural characteristics of the hamstring muscles can heighten an athlete's risk of incurring a hamstring strain. To evaluate the influence of hamstring muscle architectural characteristics (i. e., fascicle length, pennation angle, muscle thickness) on injury risk, it is necessary to precisely evaluate these characteristics. Considering this, our aim was to develop and evaluate the precision of a novel semi-automated tracing software to measure the architectural characteristics of the biceps femoris long head (the most commonly injured hamstring muscle) in B-mode ultrasound images. We acquired static sonograms of the biceps femoris long head from ten healthy male field-sport athletes. The architectural characteristics (fascicle length, pennation angle, and muscle thickness) of participants' biceps femoris long head were evaluated 10 times using the tracing software, with the specific purpose of determining its measurement precision. The tracing software precisely measured the architectural characteristics of the participants' biceps femoris long head: fascicle length (% CV: 0.64-1.12), pennation angle (% CV: 2.58-10.70), muscle thickness (% CV: 0.48-2.04) Our semi-automated skeletal muscle tracing algorithm precisely measures fascicle length, pennation angles, and muscle thickness of the biceps femoris long head in static B-mode ultrasound images.

Ambulatory shoulder arthroplasty provides a mild reduction in overall cost compared with inpatient shoulder arthroplasty cost of ambulatory shoulder arthroplasty.

HYPOTHESIS: The purpose of this study was to determine the relative cost difference of inpatient vs. ambulatory total shoulder arthroplasty (TSA) procedures. METHODS: A retrospective case series was performed to identify a consecutive series of patients who underwent primary anatomic or reverse TSA at 2 orthopedic specialty hospitals between September 2015 and August 2020. Those undergoing surgery for fracture or revision were excluded. Itemized facility costs were analyzed with a time-driven activity-based costing model and compared between ambulatory and non-ambulatory procedures. Ambulatory patients were defined as those admitted and discharged on the same calendar day. All other patients were considered non-ambulatory. RESULTS: A total of 1027 patients were analyzed, comprising 38 ambulatory patients (3.7%) and 989 non-ambulatory patients (96.3%). There was a higher proportion of anatomic TSA than reverse shoulder arthroplasty in the ambulatory group (81.6% vs. 51.7%, P < .0001). Overall, there was no difference in cost between the 2 groups ($8832 vs. $8841, P = .97). However, personnel costs were greater in the non-same-day group ($1895 vs. $2743, P < .0001) whereas supply costs were less ($6937 vs. $6097, P < .0003). When implant costs were excluded, outpatient shoulder arthroplasty provided a cost savings of $745. CONCLUSION: Ambulatory shoulder arthroplasty provides a mild cost savings of $745 after controlling for fixed costs. This is much less dramatic than previously reported and should raise concern as shoulder arthroplasty continues to be targeted by payers as a potential for cost savings through decreased reimbursement.

Outcomes of instability after reverse shoulder arthroplasty: reoperation and persistent instability are common.

HYPOTHESIS: Although risk factors for instability after reverse shoulder arthroplasty (RSA) have been extensively studied, the outcomes of patients who experience instability are unknown. The purpose of this study was to evaluate functional outcomes in patients with instability after RSA. METHODS: We retrospectively identified patients with instability after RSA with a minimum of 2 years' follow-up from an institutional database. Baseline data were recorded, and all patients we contacted to obtain clinical outcome scores. Patients who required revision surgery and those treated successfully with closed reduction were compared. RESULTS: Fifty patients were included. Of these patients, 40 (80%) required revision surgery whereas 10 (20%) were treated successfully with closed reduction. At an average follow-up of 63.7 months (range, 24-123 months), outcome scores did not differ between groups. Patients who required revision surgery were more likely to have undergone previous shoulder surgery, prior to their index arthroplasty (P = .031). Seventeen patients (42.5%) reported recurrent instability following revision surgery, and 14 (35.0%) required additional revision surgery. Ultimately, stability was never achieved in 7 of 50 patients (14%) after their index instability event. CONCLUSION: Although instability after RSA can commonly be corrected with reasonable functional results, multiple procedures may be needed and some patients may experience persistent instability.

Total shoulder arthroplasty using an inlay glenoid component for glenoid deficiency: mid- to long-term follow-up of a previously published cohort.

BACKGROUND: The short-term results of total shoulder arthroplasty with an inlay glenoid component performed by a single surgeon in patients with glenoid bone loss have previously been reported. The purpose of this study was to investigate the mid- to long-term clinical and radiographic outcomes of these patients. METHODS: We identified a cohort of patients who underwent total shoulder arthroplasty with an inlay glenoid component performed by a single surgeon between 2010 and 2019 for severe glenoid dysplasia and/or glenoid bone loss. Patients with a minimum of 2 years' follow-up were evaluated regarding preoperative and postoperative range of motion, radiographic findings, visual analog scale pain scores, and Single Assessment Numeric Evaluation scores. RESULTS: Overall, 39 shoulders in 33 patients were treated with an inlay glenoid component for severe glenoid bone loss. Four patients were lost to follow-up, and 1 patient died with a well-functioning implant in place. The final cohort included 34 shoulders in 28 patients (46.4% female patients [13 of 28] and 53.6% male patients [15 of 28]) with a mean age of 66.9 years (range, 58-81 years) and mean follow-up period of 68.3 months. Of the 34 cases, 5 were revision cases. One patient died following 2-year follow-up. Of the shoulders, 10 were classified as Walch type A2, 4 were classified as Walch type B3, and 15 were classified as Walch type C; 5 shoulders were unable to be classified. We observed statistically significant increases in range of motion (forward elevation, 38.1° [P < .001]; external rotation, 18.8° [P < .001]) and improvement in the Single Assessment Numeric Evaluation score (from 26.6 to 81.0, P < .001). Two patients underwent conversion to reverse shoulder arthroplasty at 2.2 and 1.7 years postoperatively. CONCLUSION: Inlay glenoid components provide a low rate of revision and improved clinical and functional outcomes at mid- to long-term follow-up.

Improved mechanical fixation of an all-polyethylene glenoid reduces postoperative radiolucent lines.

BACKGROUND: The rationale for advances in implant design is to improve performance in comparison to their predecessors. The purpose of this study was to compare a newer, self-pressurizing peripheral peg glenoid to a traditional polyethylene pegged glenoid through biomechanical evaluation and a retrospective radiographic and clinical review. METHODS: Three testing conditions (uncemented, partially cemented, and fully cemented) were chosen to assess the 2 component designs in a foam block model. The number of hammer hits to seat the component, amount of time to seat the component, and resistance-to-seat were collected. The implants were then cyclically loaded following ASTM F2028-17 testing standard. Clinically, postoperative radiographs of patients with a self-pressurized glenoid component (n = 225 patients) and traditional glenoid component (n = 206 patients) were evaluated for radiolucent lines and glenoid seating at various timepoints. Clinical outcomes (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Simple Shoulder Test, and visual analog scale pain scores) and complications were recorded. The presence of radiolucent lines at the bone-cement interface was evaluated using the Modified Franklin Grade and the Lazarus grade. RESULTS: The self-pressurizing glenoid design required significantly more hammer hits than traditional glenoid designs in all groups tested (P < .029). Moreover, the self-pressurizing design had significantly more resistance-to-seat than traditional components in both the uncemented and partially cemented group (P < .002). No difference in resistance-to-seat was found between designs in the fully cemented group. The uncemented and partially cemented groups did not survive the full 50,000 cycles; however the self-pressurizing design had significantly less motion than the traditional design (P < .001). No differences between component designs were found in the fully cemented group at 50,000 cycles. The self-pressurizing glenoid component had 0.005% radiographic radiolucent lines, and the traditional glenoid component had 45% radiographic radiolucent lines, with 38% of the radiolucencies in the traditional glenoid component group being defined as grade E. There were no progressive radiolucencies, differences in clinical outcomes, or complications at 2 years postoperatively. CONCLUSION: In the fully cemented condition, the 2 component designs had comparable performance; however, the differences in designs could be better observed in the uncemented group. The self-pressurizing all-polyethylene design studied has superior biomechanical stability. Clinically, the improved stability of the glenoid component correlated with a reduction of radiolucent lines and will likely lead to a reduction in glenoid component loosening.

Male Sex, Western Ontario Shoulder Instability Index Score, and Sport as Predictors of Large Labral Tears of the Shoulder: A Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability Cohort Study.

PURPOSE: To identify factors predictive of a large labral tear at the time of shoulder instability surgery. METHODS: As part of the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort, patients undergoing open or arthroscopic shoulder instability surgery for a labral tear were evaluated. Patients with >270° tears were defined as having large labral tears. To build a predictive logistic regression model for large tears, the Feasible Solutions Algorithm was used to add significant interaction effects. RESULTS: After applying exclusion criteria, 1235 patients were available for analysis. There were 222 females (18.0%) and 1013 males (82.0%) in the cohort, with an average age of 24.7 years (range 12 to 66). The prevalence of large tears was 4.6% (n = 57), with the average tear size being 141.9°. Males accounted for significantly more of the large tears seen in the cohort (94.7%, P = .01). Racquet sports (P = .01), swimming (P = .02), softball (P = .05), skiing (P = .04), and golf (P = .04) were all associated with large labral tears, as was a higher Western Ontario Shoulder Instability Index (WOSI; P = .01). Age, race, history of dislocation, and injury during sport were not associated with having a larger tear. Using our predictive logistic regression model for large tears, patients with a larger body mass index (BMI) who played contact sports were also more likely to have large tears (P = .007). CONCLUSIONS: Multiple factors were identified as being associated with large labral tears at the time of surgery, including male sex, preoperative WOSI score, and participation in certain sports including racquet sports, softball, skiing, swimming, and golf. LEVEL OF EVIDENCE: I, prognostic study.

Free Vascularized Rectus Abdominis Transfer With Pedicled Intercostal Innervation for Functional Reconstruction of the Elbow in Total Brachial Plexus Palsy.

PURPOSE: Reanimation of palsied upper limbs usually follows an escalating pattern of nerve repair, nerve transfers, and musculotendinous transfers and culminates in free functioning muscle transfers. When there are no other musculotendinous options, we explored the possibility of transferring the rectus abdominus to the biceps by maintaining the nerve pedicle but dividing the vascular pedicle and anastomosing it to the brachial artery. METHODS: We performed anatomical dissection of the nerve and blood supply of 6 rectus abdominis muscles in 3 cadavers. A retrospective analysis of 4 patients in whom a rectus abdominus muscle transfer with a pedicled nerve, but free vascular supply, was then performed. RESULTS: The anatomical feasibility study demonstrated that it was possible to elevate the rectus abdominis on its intercostal nerve supply to the midaxillary line, allowing the muscle to be pedicled on its nerve supply and be transferred to the arm to reconstruct biceps. The vascular supply could be reestablished by anastomosis of inferior epigastric vessels to the brachial artery and veins. In 4 patients, elbow flexion strength of M3 or greater was achieved. Average elbow range of dynamic flexion was 120° (range, 92° to 131°). Shoulder stability and external rotation improved in all patients with resolution of shoulder subluxation. Two patients developed donor site hernias requiring mesh reconstruction. Complications included a hypertrophic recipient site scar in one patient, and recipient site wound dehiscence in another. CONCLUSIONS: Rectus abdominus can be transferred to reconstruct elbow flexion when other musculotendinous transfers are unavailable and as an alternative to free functioning muscle transfer. However, rectus abdominus transfer still requires microsurgical skills for the vessel anastomoses. This is an effective procedure for functional reconstruction of the elbow and adds to the armamentarium in the management of brachial plexus pathology when other transfers are unavailable. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Responsiveness of patient-reported outcomes in shoulder arthroplasty: what are we actually measuring?

HYPOTHESIS: The purpose of this study was to determine the prevalence and responsiveness of common patient-reported outcome (PRO) tools in patients undergoing primary total shoulder arthroplasty (TSA) for glenohumeral arthritis. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of anatomic and reverse TSA studies from PubMed, SportDiscus, Cochrane, and CINAHL was performed. Studies on primary TSA for glenohumeral arthritis that reported at least 1 PRO tool were included in the final analysis. A subgroup analysis of studies that reported preoperative and postoperative PRO scores with at least 2-year follow-up data was evaluated to compare the responsiveness between the different PRO instruments. RESULTS: After full-text review of 490 articles, 74 articles met all inclusion criteria and were included in the final analysis. Anatomic TSA was evaluated in 35 studies, reverse TSA in 32 studies, and both anatomic and reverse in 7 studies. There were a total of 7624 patients, and 25 different PRO tools were used. The most commonly reported PRO tools were the American Shoulder and Elbow Surgeons (44 studies), Constant (42 studies), the visual analog scale for pain (23 studies), and the Simple Shoulder Test (17 studies). A median of 3.0 PRO instruments were used in each study. All instruments had large effect sizes. The University of California at Los Angeles (UCLA) score was found to be the most responsive instrument, and the Single Assessment Numeric Evaluation score was least responsive. The American Shoulder and Elbow Surgeons score was the most responsive instrument that required only patient-reported data. CONCLUSION: Overall, the UCLA score was found to be the most responsive followed by the Adjusted Constant. However, both the UCLA and Adjusted Constant scores require strength and range of motion assessment that may limit their widespread clinical use. The increased responsiveness of these measures, which include objective clinical testing, speaks to the predicted increases in strength and range of motion after shoulder arthroplasty. Of the measures that can be administered without in-person clinical evaluation, the American Shoulder and Elbow Surgeons score and Western Ontario Osteoarthritis of the Shoulder index were the most responsive.

Three-dimensional measures of posterior bone loss and retroversion in Walch B2 glenoids predict the need for an augmented anatomic glenoid component.

HYPOTHESIS: The purpose of this study is to evaluate whether the amount of measured posterior bone loss on 2- and 3-dimensional (2D and 3D) imaging of Walch B2 glenoids can reliably predict the plan for an augmented anatomic glenoid component. METHODS: Patients with Walch B2 glenoids and preoperative computed tomography (CT) scans were retrospectively identified. 2D axial CT scans were reviewed and posterior bone loss was measured by 3 independent reviewers. Images were then formatted into BluePrint (Wright Medical) preoperative planning software. The same 3 reviewers again measured posterior bone loss on 3D imaging. Additionally, all cases were planned with BluePrint software. An augment was used when the following criteria were unable to be satisfied with standard implants: <10° retroversion, <10° superior inclination, ≥90% backside contact, <2 mm medial reaming, and ≤1 peg perforation. RESULTS: Forty-two patients were included in the final analysis with a mean age of 63.1 ± 6.3 years. As measured by BluePrint, the mean retroversion was 23° ± 7° (range = 9°-40°), the mean superior inclination was 5° ± 6° (range = -9° to 22°), and the mean posterior subluxation was 80% ± 17% (range = 41%-95%). The mean 2D bone loss measurements (3.5 ± 1.6 mm) were significantly lower than the mean 3D bone loss (4.0 ± 1.8 mm) measurements (P = .03). There was substantial agreement between reviewers on both 2D and 3D measurements with an interclass correlation of 0.815 (95% confidence interval [CI] 0.714-0.889, P < .001) and an interclass correlation of 0.802 (95% CI 0.683-0.884, P < .001), respectively. Augments were used in 73.8%, 63.4%, and 63.4% of cases by reviewers 1, 2, and 3, respectively, with moderate agreement with a Fleiss kappa of 0.592 (95% CI 0.416-0.769, P < .001). Augment size was moderately, positively correlated with the amount of bone loss on 3D imaging but not with 2D imaging. After multivariate logistic regression, both 3D bone loss and retroversion were found to be predictive for a plan to use an augment. CONCLUSION: Planning for a posterior augment in Walch B2 glenoids is better predicted with 3D imaging than with 2D imaging, as 2D imaging may underestimate posterior bone loss. Additionally, use of a larger augment size is moderately correlated with posterior bone loss on 3D imaging but not 2D imaging. Standard 2D imaging may be limited in cases of posterior bone loss, and 3D imaging may be beneficial for preoperative planning in Walch B2 glenoids.

Increased Health Care Costs and Opioid Use in Patients with Anxiety and Depression Undergoing Rotator Cuff Repair.

PURPOSE: To (1) quantify the prevalence of mood disorders in patients undergoing arthroscopic rotator cuff repair (RCR) by use of a large claims database and (2) compare opioid use and medical costs in the year before and the year after RCR between patients with and without comorbid mood disorders. METHODS: A large claims database was queried to identify patients who underwent arthroscopic RCR (Current Procedural Terminology code 29827) between October 2010 and December 2015. All patients were then screened for insurance claims relating to either anxiety or depression. We compared net costs and opioid use both 1 year preoperatively and 1 year postoperatively between patients with and without mood disorders by use of an analysis of covariance. RESULTS: A total of 170,329 patients (97,427 male patients [57.2%] and 72,902 female patients [42.8%]) undergoing arthroscopic RCR were identified. Of the 170,329 patients, 46,737 (27.4%) had comorbid anxiety or depression, and after adjustment for preoperative cost, sex, age, and both preoperative and postoperative opioid use, the 1-year postoperative cost was 7.05% higher for those with a preoperative mood disorder than for those without a mood disorder. In addition, opioid use both in the 180 days prior to surgery (36.7% vs 26.9%) and more than 90 days after surgery (33.0% vs 27.2%) was substantially greater in the group with comorbid depression or anxiety. CONCLUSIONS: In patients with comorbid mood disorders, opioid use and health care costs were increased both preoperatively and postoperatively. The increased cost in this patient population is estimated at $62.3 million annually. In an effort to provide high-quality, value-based care, treatment strategies should be developed to identify these patients preoperatively and provide the appropriate resources needed to improve the probability of a successful surgical outcome. LEVEL OF EVIDENCE: Level III, retrospective, comparative therapeutic study.

Antibiotic cement spacer retention for chronic shoulder infection after minimum 2-year follow-up.

HYPOTHESIS: The treatment of periprosthetic shoulder infections and proximal humerus osteomyelitis is challenging. The outcomes of antibiotic cement spacer retention are poorly defined in the literature. The purpose of this study was to review long-term functional and patient-reported outcomes data of patients with retained antibiotic cement spacers. We predict reasonable functional outcomes and minimal pain. METHODS: We identified 22 patients of the senior author who have been treated with definitive antibiotic spacer placement. All patients were originally offered a 2-stage revision and declined. Twelve patients had a minimum follow-up of 2 years and were included in our cohort. Mean age was 70.7 (range 59-81), 8/12 patients were female, and the average body mass index was 27.8 (range = 17-45). Functional outcome assessments included the Standardized Shoulder Assessment Form, the Quick Disabilities of the Arm, Shoulder, and Hand Score (QuickDASH), and visual analog scale (VAS) along with clinical range of motion examination. RESULTS: The patients were followed up for a mean of 5.6 years. Eight patients had spacer placement for chronic shoulder arthroplasty infections, whereas 4 patients had spacer placement for chronic osteomyelitis of the proximal humerus. No patients were currently being treated with suppressive antibiotics. One patient had negative cultures at the time of antibiotic spacer placement. The most common organisms were Cutibacterium acnes (6), Staphylococcus epidermidis (6), and methicillin-resistant Staphylococcus aureus (4), with 4 patients growing more than 1 species. The average ASES score was 54 (range = 27-73), QuickDASH was 45 (range = 14-89), and VAS score 2.8 (range = 0-8). Average active range of motion was 68° of forward elevation and 35° of external rotation. CONCLUSIONS: Retention of antibiotic cement spacer is a viable option in the treatment algorithm for chronic shoulder infections. Long-term antibiotic cement spacer may be considered for those patients who are unwilling or unable to undergo a 2-stage revision. Patients can expect a reasonable amount of function and little to no pain with an antibiotic cement spacer.

Surgical outcomes in the Frequency, Etiology, Direction, and Severity (FEDS) classification system for shoulder instability.

BACKGROUND: The Frequency, Etiology, Direction, and Severity (FEDS) system was developed as a simple but reliable method for classifying shoulder instability based on 4 factors attainable by history and physical examination: frequency (solitary, occasional, or frequent); etiology (traumatic or atraumatic); direction (anterior, posterior, or inferior); and severity (subluxation or dislocation). This study investigated the epidemiology and 2-year surgical outcomes for the FEDS categories in the prospective Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort. METHODS: At the time of surgery, 1204 patients were assigned to the FEDS categories. Follow-up data were available for 636 of 734 patients (86.6%) who had undergone surgery at least 2 years prior to analysis. The most common categories were further analyzed by patient-reported outcomes (PROs) (American Shoulder and Elbow Surgeons, Western Ontario Shoulder Instability index, Single Assessment Numeric Evaluation scores) and rates of recurrent subluxation, recurrent dislocation, and revision surgery. RESULTS: Of the 36 FEDS categories, 16 represented at least 1% of patients. Occasional traumatic anterior dislocation (OTAD) was the most common category, with 16.4% of patients. Five other anterior categories (solitary traumatic anterior subluxation, occasional traumatic anterior subluxation [OTAS], frequent traumatic anterior subluxation [FTAS], solitary traumatic anterior dislocation, and frequent traumatic anterior dislocation) and one posterior category (solitary traumatic posterior subluxation [STPS]) represented at least 5% of patients. PROs improved significantly for each category. The highest rates of recurrent subluxation occurred in FTAS, OTAS, and OTAD cases; dislocation, OTAS and FTAS cases; and further surgery, OTAD cases. The lowest rates of failure occurred in STPS cases. Downward trends in PROs and higher failure rates were noted with an increasing number of preoperative dislocations. CONCLUSION: Different FEDS categories showed varying degrees of improvement and failure rates, indicating that the system can be used to provide prognostic insight for presurgical education. Overall, outcomes decreased with a higher number of preoperative dislocations.

Epidemiology of the Frequency, Etiology, Direction, and Severity (FEDS) system for classifying glenohumeral instability.

HYPOTHESIS: The purpose of this multicenter epidemiologic study was to determine the distribution of patients within the Frequency, Etiology, Direction, and Severity (FEDS) classification system to determine which categories are of clinical importance. METHODS: Shoulder instability patients were identified using International Classification of Diseases, Ninth Revision coding data from 3 separate institutions from 2005-2010. Data were collected retrospectively. Details of instability were recorded in accordance with the FEDS classification system. Each patient was assigned a classification within the FEDS system. After all patients were assigned to a group, each group was individually analyzed and compared with the other groups. RESULTS: There are a total of 36 possible combinations within the FEDS system. Only 16 categories were represented by at least 1% of our patient population. Six categories captured at least 5% of all patients with shoulder instability. Only 2 categories represented greater than 10% of the population: solitary, traumatic, anterior dislocation, with 95 patients (24.8%), and occasional, traumatic, anterior dislocation, with 63 patients (16.4%). CONCLUSIONS: There are 16 categories within the FEDS classification that are clinically significant. Solitary, traumatic, anterior dislocation and occasional, traumatic, anterior dislocation were the most frequently observed in our cohort.

Sex-related differences in patients undergoing surgery for shoulder instability: a Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort study.

HYPOTHESIS AND BACKGROUND: Male sex has been identified as a risk factor for both primary shoulder dislocation and recurrent instability, and male patients more often undergo surgery for instability. Despite published discrepancies between sexes regarding the incidence and surgical rates of shoulder instability, there is little detail on the differences in presentation, mechanism of injury, and intraoperative findings. The purpose of this study was to explore these differences. METHODS: Prospective baseline data from 1010 patients in the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort were analyzed for sex-related differences using demographic characteristics, patient-reported outcomes, radiographic findings, intraoperative findings, and surgical procedures performed. Two-tailed t tests and χ2 tests were used to compare the continuous and categorical data, respectively. Patients were categorized using the Frequency, Etiology, Direction, Severity (FEDS) classification system. RESULTS: Male patients comprised 81.3% of the cohort. Male patients had a significantly higher rate of traumatic instability and rate of initial instability while playing sports, as well as significantly higher activity scores. Female patients had significantly lower preoperative American Shoulder and Elbow Surgeons, Western Ontario Shoulder Instability Index, 36-Item Health Survey, and Single Assessment Numeric Evaluation scores. No difference in the number of dislocations was found between male and female patients. Intraoperatively, male patients had higher rates of labral pathology and bone loss whereas female patients had higher rates of capsular laxity. These differences resulted in more Latarjet procedures for male patients and more soft-tissue procedures for female patients. CONCLUSION: There are differences between male and female patients in the etiology of their instability, baseline patient-reported outcomes, and associated shoulder pathology, likely reflecting intrinsic and activity-related variation. These differences may influence clinical decision making and patient outcomes.