Glenoid Bone Loss in Shoulder Instability: Superiority of Three-Dimensional Computed Tomography over Two-Dimensional Magnetic Resonance Imaging Using Established Methodology.

BACKGROUD: Recent literature suggests that three-dimensional magnetic resonance imaging (3D MRI) can replace 3D computed tomography (3D CT) when evaluating glenoid bone loss in patients with shoulder instability. We aimed to examine if 2D MRI in conjunction with a validated predictive formula for assessment of glenoid height is equivalent to the gold standard 3D CT scans for patients with recurrent glenohumeral instability. METHODS: Patients with recurrent shoulder instability and available imaging were retrospectively reviewed. Glenoid height on 3D CT and 2D MRI was measured by two blinded raters. Difference and equivalence testing were performed using a paired t-test and two one-sided tests, respectively. The interclass correlation coefficient (ICC) was used to test for interrater reliability, and percent agreement between the measurements of one reviewer was used to assess intrarater reliability. RESULTS: Using an equivalence margin of 1 mm, 3D CT and 2D MRI were found to be different (p = 0.123). The mean glenoid height was significantly different when measured on 2D MRI (39.09 ± 2.93 mm) compared to 3D CT (38.71 ± 2.89 mm) (p = 0.032). The mean glenoid width was significantly different between 3D CT (30.13 ± 2.43 mm) and 2D MRI (27.45 ± 1.72 mm) (p < 0.001). The 3D CT measurements had better interrater agreement (ICC, 0.91) than 2D MRI measurements (ICC, 0.8). intrarater agreement was also higher on CT. CONCLUSIONS: Measurements of glenoid height using 3D CT and 2D MRI with subsequent calculation of the glenoid width using a validated methodology were not equivalent, and 3D CT was superior. Based on the validated methods for the measurement of glenoid bone loss on advanced imaging studies, 3D CT study must be preferred over 2D MRI in order to estimate the amount of glenoid bone loss in candidates for shoulder stabilization surgery and to assist in surgical decision-making.

Clinical utility of immediate postoperative radiographs following uncomplicated primary reverse shoulder arthroplasty.

BACKGROUND: It is common practice to order an immediate postoperative radiograph in the postanesthesia care unit (PACU) following reverse shoulder arthroplasty (RSA). However, with a growing emphasis on value-based care and cost-effectiveness, we question the necessity for immediate postoperative radiographs following uncomplicated, primary RSA. METHODS: From 2014-2020, patients undergoing primary RSA at a single institution by one of 3 surgeons were included in this cohort. Radiographs from the PACU and any clinic visit during the initial 3-month postoperative period were reviewed to determine if any radiographic findings from the PACU altered clinical care or decision making. RESULTS: A total of 157 patients were included in this study and 13 patients had abnormal findings during the initial 3-month postoperative period where the immediate postoperative radiograph provided clinical utility for decision making. In 9 of the 12 patients requiring revision surgery, the postoperative complication was instability. In those patients requiring revision surgery during the initial 3 months, the most common indication for primary surgery was proximal humerus nonunion. Immediate postoperative radiographs were read by the radiologist as normal/unremarkable for 100% of patients. The typical amount billed for the immediate postoperative radiograph was $544.00 per patient. CONCLUSION: Based on our findings, we see utility for an intraoperative or immediate postoperative radiograph following uncomplicated, primary RSA, especially when done as a salvage procedure for indications such as proximal humerus nonunion. However, there is low utility for obtaining an immediate postoperative radiograph in the PACU when indications include osteoarthritis or rotator cuff tear arthropathy.

Short-term outcomes associated with drain use in shoulder arthroplasties: a prospective, randomized controlled trial.

BACKGROUND: This study examined the immediate outcomes during the perioperative period associated with drains in the setting of total shoulder arthroplasty or reverse shoulder arthroplasty. We hypothesized that drain use would result in lower postoperative hemoglobin and hematocrit levels that would increase transfusion rates and longer hospital stays that would increase hospital costs. METHODS: The study prospectively randomized 100 patients (55% women; average age, 69.3 years) who underwent total shoulder arthroplasty or reverse shoulder arthroplasty to receive a closed-suction drainage device (drain group, n = 50) or not (control group, n = 50) at the time of wound closure. Basic demographic information and intraoperative and postoperative data were collected. RESULTS: The groups were similar with respect to basic patient demographics. Postoperatively, drains had no effect on transfusion rates or any perioperative complication (P > .715). There were also no significant differences in hemoglobin or hematocrit levels immediately after surgery or on postoperative day 1. On average, patients were discharged from the hospital 1.6 days and 2.1 days postoperatively in the control and drain groups, respectively (P = .124). The average cost associated for the control cohort's hospital stay was $35,796 ± $13,078 compared with $43,219 ± $24,679 for the drain cohort (P = .063). DISCUSSION: Drain use after shoulder arthroplasty had no appreciable difference on short-term perioperative outcomes, postoperative anemia, length of hospital stay, or cost. It is possible that the potential negative effects of postoperative drainage are blunted by the routine use of tranexamic acid.

Quality of Life and Functional Outcomes after Multiligament Knee Reconstruction.

We aimed to determine factors that affect the quality of life of patients undergoing a standardized surgical and postoperative management protocol for knee dislocations. A total of 31 patients (33 knees) were included in this study. We contacted patients at a minimum of 12 months postoperatively (mean: 38 months; range, 12-111 months) and administered the previously validated Multiligament Quality of Life questionnaire (ML-QOL), 2000 International Knee Documentation Committee Subjective Knee Form (IKDC), and Lysholm Knee Scoring Scale. We performed independent two-sample t-tests and age-adjusted multivariable linear regression analysis to examine the difference in these scores. Patients who underwent previous knee ligament surgery had significantly worse mean ML-QOL scores relative to patients who did not undergo previous knee ligament surgery (114.3 versus 80.4; p = 0.004) (higher score indicates worse quality of life). All other differences in the ML-QOL scores were not statistically significant. IKDC and Lysholm scores did not differ significantly with regards to the studied variables. Among patients with no previous knee ligament surgery, patients undergoing surgery within 3 weeks of injury had significantly worse mean ML-QOL scores relative to patients undergoing surgery greater than 3 weeks after their injury (98.7 versus 74.7; p = 0.042) and patients with Schenck classification of III or IV had significantly worse mean ML-QOL scores relative to patient with a Schenck classification of I or II (88.7 versus 62.9; p = 0.015). We found that patients with a previous history of knee ligament surgery had a significantly worse quality of life relative to those with no history of knee ligament surgery. This is a level III, retrospective cohort study.

Effect of charted mental illness on reperfusion therapy in hospitalized patients with an acute myocardial infarction in Florida.

Patients with mental illness carry risk factors that predispose them to excess cardiovascular mortality from an acute myocardial infarction (AMI) compared to the general population. The aim of this study was to determine if patients with AMI and charted mental illness (CMI) received less reperfusion therapy following an AMI, compared to AMI patients without CMI in a recent sample population from Florida.A secondary analysis of data was conducted using the Florida Agency for Health Care Administration (FL-AHCA) hospital discharge registry. Adults hospitalized with an AMI from 01/01/2010 to 12/31/2015 were included for the analysis. The dependent variable was administration of reperfusion therapy (thrombolytic, percutaneous coronary intervention [PCI], and coronary artery bypass graft [CABG]), and the independent variable was the presence of CMI (depression, schizophrenia, and bipolar disorder). Multivariate logistic regression models were used to test the association controlling for age, gender, ethnicity, race, health insurance, and comorbidities.The database included 61,614 adults (31.3% women) hospitalized with AMI in Florida. The CMI population comprised of 1036 patients (1.7%) who were on average 5 years younger than non-CMI (60.2 ±12.8 versus 65.2 ±14.1; P < .001). Compared with patients without CMI, patients with CMI had higher proportions of women, governmental health insurance holders, and those with more comorbidities. The adjusted odds ratio indicated that patients with CMI were 30% less likely to receive reperfusion therapy compared with those without CMI (OR = 0.7; 95% CI = 0.6-0.8). Within the AMI population including those with and without CMI, women were 23% less likely to receive therapy than men; blacks were 26% less likely to receive reperfusion therapy than whites; and those holding government health insurances were between 20% and 40% less likely to receive reperfusion therapy than those with private health insurance.Patients with AMI and CMI were statistically significantly less likely to receive reperfusion therapy compared with patients without CMI. These findings highlight the need to implement AMI management care aimed to reduce disparities among medically vulnerable patients (those with CMI, women, blacks, and those with governmental health insurance).

Pronator Teres Myotendinous Tear.

Pronator teres muscle strain is a rare sporting injury reported thus far only in cricket and golf players. The injury appears to occur when the sporting club or racket strikes the ground during a forceful swing and causes the elbow to experience an eccentric force during resisted elbow flexion and pronation. On initial presentation, this injury can be mistaken for injury to the medial ulnar collateral ligament, or exacerbation of medial epicondylitis. On examination, bruising and tenderness distal to the elbow over the course of the pronator teres are often present. Advanced imaging confirms the diagnosis and can help in grading injury severity. In this article, we report the case of a patient who was conservatively treated, and returned to function and sport by 6 weeks after a period of rest and restricted activities. The prognosis is excellent for even high-grade strains. Complete return to sporting function without residual weakness is expected.

Measurement of Clavicle Fracture Shortening Using Computed Tomography and Chest Radiography.

BACKGROUND: Nonoperative management of midshaft clavicle fractures has resulted in widely disparate outcomes and there is growing evidence that clavicle shortening poses the risk of unsatisfactory functional outcomes due to shoulder weakness and nonunion. Unfortunately, the literature does not clearly demonstrate the superiority of one particular method for measuring clavicle shortening. The purpose of this study was to compare the accuracy of clavicle shortening measurements based on plain radiographs with those based on computed tomography (CT) reconstructed images of the clavicle. METHODS: A total of 51 patients with midshaft clavicle fractures who underwent both a chest CT scan and standardized anteroposterior chest radiography on the day of admission were included in this study. Both an orthopedic surgeon and a musculoskeletal radiologist measured clavicle shortening for all included patients. We then determined the accuracy and intraclass correlation coefficients for the imaging modalities. Bland-Altman plots were created to analyze agreement between the modalities and a paired t-test was used to determine any significant difference between measurements. RESULTS: For injured clavicles, radiographic measurements significantly overestimated the clavicular length by a mean of 8.2 mm (standard deviation [SD], ± 10.2; confidence interval [CI], 95%) compared to CT-based measurements (p < 0.001). The intraclass correlation was 0.96 for both plain radiograph- and CT-based measurements (p = 0.17). CONCLUSIONS: We found that plain radiograph-based measurements of midshaft clavicle shortening are precise, but inaccurate. When clavicle shortening is considered in the decision to pursue operative management, we do not recommend the use of plain radiograph-based measurements.

Valgus Extension Overload in Baseball Players.

Repetitive throwing, such as in baseball pitching, applies massive stress on the elbow. This can often lead to a predictable constellation of elbow injuries, such as valgus extension overload syndrome (VEO). The following review of VEO provides an understanding of relevant anatomy, explanation of pathomechanics, key aspects to clinical evaluation, effective treatment options, and indications for surgery. In addition, we provide the senior author's (CSA) preferred arthroscopic technique for cases of VEO refractory to conservative management.

Radiographic Landmarks for Identifying the Anterolateral Ligament of the Knee.

PURPOSE: To identify the radiographic position of the origin and insertion of the anterolateral ligament (ALL) of the knee on a lateral radiograph. METHODS: Twelve unpaired, fresh-frozen cadaveric knees were dissected to expose the ALL. The origin and insertion of the ALL on each cadaver were then tagged using 2-mm radiopaque beads. True lateral fluoroscopic views of the knee were then obtained, and the distance from known radiographic landmarks was recorded by 2 reviewers. RESULTS: The origin of the ALL was found at a distance that is 37.0 ± 9.2% of the total anterior-posterior length of the femoral condyle from the posterior edge as measured along Blumensaat's line. The insertion was located at a distance that is 56.1 ± 6.9% of the total length of the tibial plateau from the posterior edge. The origin of the ALL is 5 mm posterior to a line from the posterior femoral cortex and 9 mm distal to a line along Blumensaat's line. The insertion is 4 mm anterior to the 50% mark of the anterior-posterior width of the tibia, 14 mm distal to the articular surface. CONCLUSIONS: The origin and insertion of the ALL can be accurately identified using intraoperative fluoroscopy. CLINICAL RELEVANCE: Determining radiographic parameters for the ALL will assist in developing accurate surgical techniques for ALL reconstruction.

Complication rate and implant survival for reverse shoulder arthroplasty versus total shoulder arthroplasty: results during the initial 2 years.

BACKGROUND: The use of reverse total shoulder arthroplasty (RTSA) has significantly increased in recent years. However, there is large variance in reported complication rates and sparse data on implant survival. This study used a statewide patient database to investigate complication rates and implant survival for RTSA. METHODS: All patients undergoing RTSA or total shoulder arthroplasty (TSA) from 2011 to 2013 were identified within a statewide database. The complication and revision rates at 30 days, 90 days, 1 year, and 2 years postoperatively were determined. Potential risk factors for complications were analyzed with logistic regression, and Kaplan-Meier survival curves were used to compare implant failure. RESULTS: During the 3-year period, 10,844 procedures (6,658 TSA; 4,186 RTSA) were found within the database. The all-cause complication rate at 90 days and 2 years postoperatively was significantly higher for RTSA (P < .001). RTSA patients had a significantly increased risk of infection (P < .05) and dislocation (P < .001) in the early and midterm postoperative course. Workers' compensation, male sex, preoperative anemia, and those aged younger than 65 years had a significantly higher risk for complications (P < .001). Although RTSA initially had a higher rate of implant failure than TSA during the early postoperative period, this rate equalized at approximately the 1-year mark. CONCLUSION: RTSA patients had significantly higher complication rates compared with TSA patients, with identifiable risk factors for all-cause complications postoperatively and equivalent accepted implant failure at 2 years. LEVEL OF EVIDENCE: Level III; Cross Sectional Design; Large Database Analysis.

Acute Compartment Syndrome after Non-Contact Peroneus Longus Muscle Rupture.

This case demonstrates a rare variation in the pattern of injury and the presentation of acute lateral compartment syndrome of the leg. Although uncommon, lateral compartment syndrome of the leg after an ankle inversion leading to peroneus longus muscle rupture has been previously documented. This case was unusual because there was no overt ankle injury and the patient was able to continue physical activity, in spite of a significant rupture of the peroneus longus muscle that was determined later. This case highlights the necessary vigilance clinicians must maintain when assessing non-contact injuries in patients with possible compartment syndrome.

A Comparison of Rehabilitation Methods After Arthroscopic Rotator Cuff Repair: A Systematic Review.

CONTEXT: Despite the significant attention directed toward optimizing arthroscopic rotator cuff repair, there has been less focus on rehabilitation after rotator cuff repair surgery. OBJECTIVE: To determine the effect of different rehabilitation protocols on clinical outcomes by comparing early versus late mobilization approaches and continuous passive mobilization (CPM) versus manual therapy after arthroscopic rotator cuff repair. DATA SOURCES: PubMed was searched for relevant articles using the keywords rotator cuff, rotator, cuff, tears, lacerations, and rehabilitation to identify articles published from January 1980 to March 2014. STUDY SELECTION: Inclusion criteria consisted of articles of level 1 or 2 evidence, written in the English language, and with reported outcomes for early versus late mobilization or rehabilitation with CPM versus manual therapy after primary arthroscopic rotator cuff repair. Exclusion criteria consisted of articles of level 3, 4, or 5 evidence, non-English language, and those with significantly different demographic variables between study groups. Included studies were evaluated with the Consolidated Standards of Reporting Trials criteria. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 2. DATA EXTRACTION: Level of evidence, study type, number of patients enrolled, number of patients at final follow-up, length of follow-up, age, sex, rotator cuff tear size, surgical technique, and concomitant operative procedures were extracted from included articles. Postoperative data included clinical outcome scores, visual analog score for pain, shoulder range of motion, strength, and rotator cuff retear rates. RESULTS: A total of 7 studies met all criteria and were included in the final analysis. Five studies compared early and late mobilization. Two studies compared CPM and manual therapy. CONCLUSION: In general, current data do not definitively demonstrate a significant difference between postoperative rotator cuff rehabilitation protocols that stress different timing of mobilization and use of CPM.

Subacromial volume and rotator cuff tears: Does an association exist?

BACKGROUND: Rotator cuff pathology occurs commonly and its cause is likely multifocal in origin. The development and progression of rotator cuff injury, especially in relation to extrinsic shoulder compression, remain unclear. Traditionally, certain acromial morphologies have been thought to contribute to rotator cuff injury by physically decreasing the subacromial space. The relationship between subacromial space volume and rotator cuff tears (RCT) has, however, never been experimentally confirmed. In this study, we retrospectively compared a control patient population to patients with partial or complete RCTs in an attempt to quantify the relationship between subacromial volume and tear type. MATERIALS AND METHODS: We retrospectively identified a total of 46 eligible patients who each had shoulder magnetic resonance imaging (MRI) performed from January to December of 2008. These patients were stratified into control, partial RCT, and full-thickness RCT groups. Subacromial volume was estimated for each patient by averaging five sequential MRI measurements of subacromial cross-sectional areas. These volumes were compared between control and experimental groups using the Student's t-test. RESULTS: With the numbers available, there was no statistically significant difference in subacromial volume measured between: the control group and patients diagnosed partial RCT (P > 0.339), the control group and patients with complete RCTs (P > 0.431). CONCLUSION: We conclude that subacromial volumes cannot be reliably used to predict RCT type.

Surgical anatomy of the lower trapezius tendon transfer.

BACKGROUND: The precise surgical anatomy of the lower trapezius tendon transfer has not been well described. A precise anatomic description of the different trapezius segments and the associated neurovascular structures is crucial for operative planning and execution. We aimed (1) to establish a reliable demarcation between the middle and lower trapezius, (2) to establish the precise relationship of the main neurovascular pedicle to the muscle belly, and (3) to evaluate the utility of the relationships established in (1) and (2) by using the results of this study to perform cadaveric lower trapezius tendon harvest. METHODS: In phase 1, a single surgeon performed all measurements using 10 cadavers. In phase 2, 10 cadaveric shoulders were used to harvest the tendon by using the relationships established in phase 1. RESULTS: We found anatomically distinct insertion sites for the lower and middle trapezius. The lower trapezius inserted at the scapular spine dorsum and the middle trapezius inserted broadly along the superior surface of the scapular spine. The distance from tip of tendon insertion to the nearest nerve at the most superior portion of the lower trapezius was 58 mm (standard deviation ± 18). By use of these relationships, there were no cases of neurovascular injury during our cadaveric tendon harvests. CONCLUSION: The lower trapezius can be reliably and consistently identified without violating fibers of the middle trapezius. Muscle splitting can be performed safely without encountering the spinal accessory nerve (approximately 2 cm medial to the medial scapular border).

Combined Glenoid and Humeral Head Reconstruction with Allografts: A Report of Two Cases and the Midterm Outcomes.

CASE: We present two cases of anterior glenohumeral instability in which both the humeral head and the glenoid were reconstructed concurrently with use of allografts; we discuss the midterm outcomes at four and one-half and five years of follow-up, respectively. CONCLUSION: In our experience, concomitant glenoid and humeral head allograft reconstruction for anterior glenohumeral instability with severe combined humeral head and glenoid pathology yielded good midterm clinical, functional, and radiographic outcomes. This treatment approach may be a viable option for young and active patients presenting with severe combined glenoid and humeral pathology and warrants additional investigation.

Does patient sex affect the anatomic relationships between the sternoclavicular joint and posterior vascular structures?

BACKGROUND: Despite increased concern for injury during surgical reconstruction of the sternoclavicular joint, to our knowledge there are few studies detailing the vascular relationships adjacent to the joint. QUESTIONS/PURPOSES: We investigated sex differences in the following relationships for sternoclavicular joint reconstruction: (1) safe distance from the posterior surface of the medial clavicle's medial and lateral segments to the major vessels, (2) length of the first costal cartilage and safe distance from the first rib to the internal mammary artery, (3) minimum distance medial to the sternoclavicular joint for optimal hole placement, and (4) safe distance from the manubrium to the great vessels. METHODS: Fifty normal postcontrast CT scans of the chest were reviewed. Means, standard deviations, and 95% CI were calculated for each aforementioned measurement. A t-test was used to determine if a sex difference exists (p≤0.05). RESULTS: At the medial end of the clavicle, the safe distance from the medial segment (first 10 mm) to the major vessels was greater in males than in females (3.5 mm versus 2.4 mm, respectively; 95% CI, 3 mm-4 mm versus 1.7 mm-3 mm, respectively; p=0.014). For the lateral segment (next 10 mm), the distance also was safer in males than in females (3.3 mm versus 1.7 mm, respectively; 95% CI, 2.7 mm-4 mm versus 1.1 mm-2.3 mm, respectively; p<0.001). The mean length of the first costal cartilage also was greater in males (35.8 mm versus 30.1 mm, respectively; 95% CI, 33.8 mm-37.8 mm versus 28.5 mm-31.9 mm, respectively; p<0.001); the distance from the first costochondral joint to the internal mammary artery was safer in males than in females (19.1 mm versus 15.4 mm, respectively; 95% CI, 16.5 mm-21.8 mm versus 13 mm-17.9 mm, respectively; p=0.05). The minimum distance to avoid inadvertent penetration of the sternoclavicular joint was greater in males than in females (16 mm versus 12.3 mm, respectively; 95% CI, 14.6 mm-17.5 mm versus 11 mm-13.6 mm, respectively; p<0.001). The distance to vessels after penetration of the manubrium was not different between males and females (5.6 mm versus 3.9, respectively; 95% CI, 4.4 mm-6.8 mm versus 2.6 mm-5.2 mm, respectively; p=0.06). CONCLUSIONS: This study makes apparent the intimate relationships between vessels and the musculoskeletal structures associated with sternoclavicular reconstruction. Based on our findings, we recommend considering the sex of the patient, using caution when drilling, and protecting essential structures posterior to the joint.

Prevalence of Abnormal Vitamin D Levels Among Division I NCAA Athletes.

BACKGROUND: Up to 1 billion people have insufficient or deficient vitamin D levels. Despite the well-documented, widespread prevalence of low vitamin D levels and the importance of vitamin D for athletes, there is a paucity of research investigating the prevalence of vitamin D deficiency in athletes. HYPOTHESIS: We investigated the prevalence of abnormal vitamin D levels in National Collegiate Athletic Association (NCAA) Division I college athletes at a single institution. We hypothesized that vitamin D insufficiency is prevalent among our cohort. STUDY DESIGN: Cohort study. LEVEL OF EVIDENCE: Level 1. METHODS: We measured serum 25-hydroxyvitamin D (25(OH)D) levels of 223 NCAA Division I athletes between June 2012 and August 2012. The prevalence of normal (≥32 ng/mL), insufficient (20 to <32 ng/mL), and deficient (<20 ng/mL) vitamin D levels was determined. Logistic regression was utilized to analyze risk factors for abnormal vitamin D levels. RESULTS: The mean serum 25(OH)D level for the 223 members of this study was 40.1 ± 14.9 ng/mL. Overall, 148 (66.4%) participants had sufficient 25(OH)D levels, and 75 (33.6%) had abnormal levels. Univariate analysis revealed the following significant predictors of abnormal vitamin D levels: male sex (odds ratio [OR] = 2.83; P = 0.0006), Hispanic race (OR = 6.07; P = 0.0063), black race (OR = 19.1; P < 0.0001), and dark skin tone (OR = 15.2; P < 0.0001). Only dark skin tone remained a significant predictor of abnormal vitamin D levels after multivariate analysis (adjusted OR = 15.2; P < 0.0001). CONCLUSION: In a large cohort of NCAA athletes, more than one third had abnormal vitamin D levels. Races with dark skin tones are at much higher risk than white athletes. Male athletes are more likely than female athletes to be vitamin D deficient. Our study demonstrates a high prevalence of vitamin D deficiency among healthy NCAA athletes. CLINICAL RELEVANCE: Many studies indicate a significant prevalence of vitamin-D insufficiency across various populations. Recent studies have demonstrated a direct relationship between serum 25(OH)D levels and muscle power, force, velocity, and optimal bone mass. In fact, studies examining muscle biopsies from patients with low vitamin D levels have demonstrated atrophic changes in type II muscle fibers, which are crucial to most athletes. Furthermore, insufficient 25(OH)D levels can result in secondary hyperparathyroidism, increased bone turnover, bone loss, and increased risk of low trauma fractures and muscle injuries. Despite this well-documented relationship between vitamin D and athletic performance, the prevalence of vitamin D deficiency in NCAA athletes has not been well studied.

Serum interleukin-6 as a marker of periprosthetic shoulder infection.

BACKGROUND: Infection after shoulder arthroplasty can be a devastating complication, and subacute and chronic low-grade infections have proven difficult to diagnose. Serum marker analyses commonly used to diagnose periprosthetic infection are often inconclusive. The purpose of this study was to evaluate the effectiveness of serum interleukin-6 (IL-6) as a marker of periprosthetic shoulder infection. METHODS: A prospective cohort study of thirty-four patients who had previously undergone shoulder arthroplasty and required revision surgery was conducted. The serum levels of IL-6 and C-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), and the white blood-cell count (WBC) were measured. The definitive diagnosis of an infection was determined by growth of bacteria on culture of intraoperative specimens. Two-sample Wilcoxon rank-sum (Mann-Whitney) tests were used to determine the presence of a significant difference in the ESR and WBC between patients with and those without infection, while the Fisher exact test was used to assess differences in IL-6 and CRP levels between those groups. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of each marker were also calculated. RESULTS: There was no significant difference in the IL-6 level, WBC, ESR, or CRP level between patients with and those without infection. With a normal serum IL-6 level defined as <10 pg/mL, this test had a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 0.14, 0.95, 0.67, 0.61, and 0.62, respectively. CONCLUSIONS: IL-6 analysis may have utility as a confirmatory test but is not an effective screening tool for periprosthetic shoulder infection. This finding is in contrast to the observation, in previous studies, that IL-6 is more sensitive than traditional serum markers for periprosthetic infection.