Mark T. Dillon

Patient and Procedure-specific Risk Factors for Deep Infection After Primary Shoulder Arthroplasty

BackgroundDeep infection after shoulder arthroplasty is a diagnostic and therapeutic challenge. The current literature on this topic is from single institutions or Medicare samples, lacking generalizability to the larger shoulder arthroplasty population.Questions/purposesWe sought to identify (1) patient-specific risk factors for deep infection, and (2) the pathogen profile after primary shoulder arthroplasty in a large integrated healthcare system.MethodsA retrospective cohort study was conducted. Of 4528 patients identified, 320 had died and 302 were lost to followup. The remaining 3906 patients had a mean followup of 2.7 years (1 day-7 years). The study endpoint was the diagnosis of deep infection, which was defined as revision surgery for infection supported clinically by more than one of the following criteria: purulent drainage from the deep incision, fever, localized pain or tenderness, a positive deep culture, and/or a diagnosis of deep infection made by the operating surgeon based on intraoperative findings. Risk factors evaluated included age, sex, race, BMI, diabetes status, American Society for Anesthesiologists (ASA) score, traumatic versus elective procedure, and type of surgical implant. For patients with deep infections, we reviewed the surgical notes and microbiology records for the pathogen profile. Multivariable Cox regression models were used to evaluate the association of risk factors and deep infection. Adjusted hazard ratios and 95% CI are presented.ResultsWith every 1-year increase in age, a 5% (95% CI, 2%–8%) lower risk of infection was observed. Male patients had a risk of infection of 2.59 times (95% CI, 1.27–5.31) greater than female patients. Patients undergoing primary reverse total shoulder arthroplasty had a 6.11 times (95% CI, 2.65–14.07) greater risk of infection compared with patients having primary unconstrained total shoulder arthroplasty. Patients having traumatic arthroplasties were 2.98 times (95% CI, 1.15–7.74) more likely to have an infection develop than patients having elective arthroplasties. BMI, race, ASA score, and diabetes status were not associated with infection risk (all p > 0.05). Propionibacterium acnes was the most commonly cultured organism, accounting for 31% of isolates.ConclusionsYounger, male patients are at greater risk for deep infection after primary shoulder arthroplasty. Reverse total shoulder arthroplasty and traumatic shoulder arthroplasties also carry a greater risk for infection. Propionibacterium acnes was the most prevalent pathogen causing infection in our primary shoulder arthroplasty population.Level of Evidence Level II, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.

Shoulder arthroplasty in patients 59 years of age and younger

BACKGROUND While shoulder arthroplasty is a well established treatment for a variety of conditions about the shoulder, the results of shoulder replacement in younger patients are not as predictable. The purpose of this study is to examine the indications for shoulder arthroplasty in patients 59 years old and younger, and to analyze revision rates between younger and older patients. METHODS This is a retrospective cohort study of shoulder arthroplasties performed within a statewide integrated healthcare system between 2005 and 2010. Patients were stratified into 2 groups based on age at time of index replacement procedure: younger patients (≤59 years) and older patients (>59 years). RESULTS There were 2981 primary arthroplasties followed for a median time of 2.2 years (interquartile range, 1.0-3.8), 90 (3.0%) of which required revisions. After adjusting for procedure type and diagnosis, younger patients had a two times higher risk (95% CI 1.2-3.5, P = .007) of revision than older patients. When looking at the risk of revision in younger and older patients separately, the risk of revision in hemiarthroplasty (RR = 4.5 vs RR = 1.7) and reverse total shoulder arthroplasty (RR = 33.6 vs RR = 3.0) compared to total shoulder arthroplasty were higher in younger patients compared to older patients. CONCLUSION This study suggests patients 59 years and younger have an increased risk of revision at early follow-up. The higher risk of revision in younger patients receiving hemiarthroplasty may support the use of total shoulder arthroplasty in patients 59 years of age and younger.

The Kaiser Permanente Shoulder Arthroplasty Registry: Results from 6,336 primary shoulder arthroplasties

Background and purpose — Shoulder arthroplasty is being performed in the United States with increasing frequency. We describe the medium-term findings from a large integrated healthcare system shoulder arthroplasty registry. Patients and methods — Shoulder arthroplasty cases registered between January 2005 and June 2013 were included for analysis. The registry included patient characteristics, surgical information, implant data, attrition, and patient outcomes such as surgical site infections, venous thromboembolism, and revision procedures. Results — During the study period, 6,336 primary cases were registered. Median follow-up time for all primaries was 3.3 years; 461 cases were lost to follow-up by ending of health plan membership. Primary cases were predominantly female (56%) and white (81%), with an average age of 70 years. The most common reason for surgery was osteoarthritis in 60% of cases, followed by acute fracture (17%) and rotator cuff tear arthropathy (15%). In elective shoulder arthroplasty procedures, 200 all-cause revisions (4%) were reported, with glenoid wear being the most common reason. Interpretation — Most arthroplasties were elective procedures: over half performed for osteoarthritis. Glenoid wear was the most common reason for revision of primary shoulder arthroplasty in elective cases.

Understanding Orthopaedic Registry Studies: A Comparison with Clinical Studies.

Orthopaedic registries are valuable for monitoring patient outcomes in real-world settings. Registries are useful for identifying procedure incidence and device utilization, evaluating outcomes, determining patients at risk for complications and reoperations, identifying devices in recall situations, assessing comparative effectiveness of procedures and devices, and providing data for research studies. In the present report, we describe how orthopaedic registries can be used to conduct research and how they compare with randomized controlled trials (RCTs) in regard to methodology. Using an example, a comparison of the performance of mobile and fixed bearings in total knee arthroplasty, we evaluate the differences between, and the similarities of, RCTs and registry cohort studies with regard to how they are conducted and how their findings are reported. Orthopaedic registry studies differ from RCTs in many ways and offer certain advantages. The strengths and limitations of registry cohort studies and RCTs must be understood to properly evaluate the literature.

Complications in total shoulder and reverse total shoulder arthroplasty by body mass index

INTRODUCTION The purpose of this study was to identify the effects of body mass index (BMI) on long-term outcomes (revision rate, 1-year mortality rate, 3-year surgical site infection rate, and 90-day inpatient all-cause readmission rate) after total shoulder arthroplasty (TSA) and reverse TSA (RTSA). METHODS A large shoulder arthroplasty registry was used to review outcomes after TSA and RTSA. The registry monitors patients revision, mortality, infection, and readmission rates. The exposure of interest was the patients BMI at the time of the surgery, which was stratified by 5 kg/m2 increments. RESULTS Selected for this study were 4630 patients who underwent TSA and RTSA between 2007 and 2013, of which 3483 (75.2%) were TSA and 1147 (24.8%) were RTSA. The overall combined (TSA and RTSA) revision rate was 1.7%. After adjusting for confounders in the overall models (TSA and RTSA combined), higher BMI was not associated with higher risk of aseptic revision, 1-year mortality, or 3-year deep infection. In TSA-specific models, every 5 kg/m2 increase in BMI was marginally associated with a 16% increase in the likelihood of 90-day readmission. This association was not observed in the RTSA model. In RTSA-specific models, every 5 kg/m2 increase in BMI was marginally associated with higher risk of 3-year deep infection. This association was not observed in the TSA model. CONCLUSION Shoulder arthroplasty in obese patients is not associated with higher risk of aseptic revision. The BMI has different effects on TSA and RSA. The surgeon should anticipate increased risk of readmission after TSA and infection after RSA.

Yearly Trends in Elective Shoulder Arthroplasty, 2005–2013

To evaluate the change in incidence rate of shoulder arthroplasty, the utilization of shoulder arthroplasty for specific indications, and the surgeon volume trends associated with these procedures between 2005 and 2013.

Treatment of chronic biceps tendon ruptures.

Repair of distal biceps tendon ruptures has become widely accepted. Unfortunately, care of chronic injuries remains a challenge to the orthopedic surgeon. Patients with chronic ruptures often present complaining of weakness in elbow flexion and supination. Nonoperative management of these injuries does not restore function to the elbow. Tenodesis of the biceps tendon to the brachialis may improve flexion strength but does not reliably improve supination weakness. Addressing these injuries through restoration of anatomy, either with direct repair of the tendon to the radial tuberosity or with the use of a tendon graft to regain length, results in improved functional outcomes. Complications rates appear to be increased when surgery is performed in chronic injuries compared to those operated upon acutely.

Yearly Trends in Elective Shoulder Arthroplasty, 2005 through 2013

To evaluate the change in incidence rate of shoulder arthroplasty, the utilization of shoulder arthroplasty for specific indications, and the surgeon volume trends associated with these procedures between 2005 and 2013.

Revision to a reverse shoulder arthroplasty using a custom glenoid sphere over a well-fixed metal glenoid tray: A case report

Rotator cuff tears are a relatively common cause of recurrent pain and loss of function in patients who have undergone total shoulder arthroplasty. If the tear is large enough, particularly in the presence of coracoacromial arch insufficiency, anterosuperior escape with attempted elevation occurs and results in pseudoparalysis. Reverse arthroplasty is one of the few procedures that can restore stability and improve function in patients with this type of glenohumeral pseudoparalysis. Adequate glenoid bone stock is a prerequisite for placement of the glenoid component of a reverse shoulder arthroplasty. Conversion to a reverse arthroplasty from an anatomic total shoulder arthroplasty often is difficult because of glenoid bone deficiency after removal of the previous glenoid component. This can be especially true after removal of a well-fixed metal-backed glenoid component. We report the use of a custom glenoid sphere secured to a well-fixed metal tray in a patient undergoing revision of an anatomic total shoulder replacement to a reverse arthroplasty for rotator cuff deficiency associated with anterosuperior dislocation.

Risk factors for postoperative opioid use after elective shoulder arthroplasty

BACKGROUND The opioid epidemic remains a serious issue in the United States with significant impact to the medical and socioeconomic welfare of communities. We sought to determine baseline opioid use in patients undergoing shoulder arthroplasty (SA) and identify patient characteristics, comorbidities, and surgical risk factors associated with postoperative opioid use. METHODS A Shoulder Arthroplasty Registry identified the number of dispensed opioid medication prescriptions (Rxs) in the first postoperative year in patients who underwent elective primary SA from 2008 to 2014. We used Poisson regression to study the effect of preoperative risks factors on number of dispensed opioid Rxs in the first postoperative year, evaluated quarterly (Q1: days 0-90, Q2: days 91-180, Q3: days 181-270, Q4: days 271-360). RESULTS Included were 4243 SAs from 3996 patients, and 75% used opioids in the 1-year preoperative period. The factors associated with increased opioid use in all postoperative quarters (Q4 incident rate ratio [IRR] shown) were age <60 years (IRR, 1.40; 95% confidence interval [CI], 1.29-1.51), preoperative opioid use (1-4 Rxs: IRR, 2.15; 95% CI, 1.85-2.51; ≥5 Rxs: IRR, 9.83; 95% CI , 8.53-11.32), anxiety (IRR, 1.11; 95% CI, 1.03-1.20), opioid dependence (IRR, 1.23; 95% CI, 1.05-1.43), substance abuse (IRR, 1.17; 95% CI, 1.07-1.28), and general chronic pain (IRR, 1.38; 95% CI, 1.28-1.50). CONCLUSION Opioid usage in patients undergoing SA is widespread at 1 year, with three-fourths of patients having been dispensed at least one Rx. These findings emphasize the need for surgeon and patient awareness as well as education in the management of postoperative opioid usage associated with the indicated conditions. Surgeons may consider these risk factors for preoperative risk stratification and targeted deployment of preventative strategies.