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Early findings of superior total knee arthroplasty (TKA) outcomes at high volume centers have been thought to have led to distinct referral patterns. However, the effect of these selective referral processes has not been well assessed. Therefore, this study compared the characteristics of primary TKA patients at high, intermediate, and low volume hospitals.A total of 12,541 primary TKA patients were stratified into risk groups based on age (65 years), body mass index (40), and Charlson Comorbidity Index (≥4). Hospitals were classified as low, intermediate, or high volume based on mean annual TKA volumes (250, 250-499, and500). Multivariate logistic regression models evaluated the relationship between baseline patient characteristics and hospital volume.There was a greater percentage of high risk patients at high volume (19%, n = 853) compared to those at intermediate (16%, n = 899) or low volume (17%, n = 444) hospitals (P.001). Patients with a body mass index40 were more likely to be treated at high compared to intermediate (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.2-1.6, P.001) and low volume centers (OR 1.4, 95% CI 1.2-1.7, P.001). Patients with Charlson Comorbidity Index scores ≥4 were also more likely be treated at high compared to intermediate (OR 1.5, 95% CI 1.3-1.6, P.001) or low (OR 1.2, 95% CI 1.0-1.4, P = .002) volume centers.This study found that TKA patients at high volume centers have significantly different baseline characteristics compared to those at lower volume centers. This study highlights the importance of considering hospital volume status and the associated disparity in the preoperative risk of patients when comparing primary TKA outcomes between centers.

Background Discharge to rehabilitation or a skilled nursing facility (SNF) after total joint arthroplasty remains a primary driver of cost excess for bundled payments. An accurate preoperative risk prediction tool would help providers and health systems identify and modulate perioperative care for higher risk individuals and serve as a vital tool in preoperative clinic as part of shared decision-making regarding the risks/benefits of surgery. Methods A total of 10,155 primary total knee (5,570, 55%) and hip (4,585, 45%) arthroplasties performed between June 2013 and January 2018 at a single institution were reviewed. The predictive ability of 45 variables for discharge location (SNF/rehab vs home) was tested, including preoperative sociodemographic factors, intraoperative metrics, postoperative labs, as well as 30 Elixhauser comorbidities. Parameters surviving selection were included in a multivariable logistic regression model, which was calibrated using 20,000 bootstrapped samples. Results A total of 1786 (17.6%) cases were discharged to a SNF/rehab, and a multivariable logistic regression model demonstrated excellent predictive accuracy (area under the receiver operator characteristic curve: 0.824) despite requiring only 9 preoperative variables: age, partner status, the American Society of Anesthesiologists score, body mass index, gender, neurologic disease, electrolyte disorder, paralysis, and pulmonary circulation disorder. Notably, this model was independent of surgery (knee vs hip). Internal validation showed no loss of accuracy (area under the receiver operator characteristic curve: 0.8216, mean squared error: 0.0004) after bias correction for overfitting, and the model was incorporated into a readily available, online prediction tool for easy clinical use. Conclusion This convenient, interactive tool for estimating likelihood of discharge to a SNF/rehab achieves excellent accuracy using exclusively preoperative factors. These should form the basis for improved reimbursement legislation adjusting for patient risk, ensuring no disparities in access arise for vulnerable populations. Level of Evidence III.

Background A recent systematic review demonstrated that reinfection rates following eradication of hip and knee periprosthetic joint infection (PJI) may be as high as 29%. This study aimed to develop a preoperative risk calculator for assessing patient’s individual risk associated with reinfection following treatment of PJI in total joint arthroplasty (TJA). Methods A total of 1081 consecutive patients who underwent revision TJA for PJI were evaluated. In total, 293 patients were diagnosed with TJA reinfection. A total of 56 risk factors, including patient characteristics and surgical variables, were evaluated with multivariate regression analysis. Analysis of the area under the receiver operating characteristics curve was performed to evaluate the strength of the predictive model. Results Of the 56 risk factors studied, 19 were found to have a significant effect as risk factor for TJA reinfection. The strongest predictors for TJA reinfection included previous PJI treatment techniques such as irrigation and debridement, the number of previous surgical interventions, medical comorbidities such as obesity, drug abuse, depression and smoking, as well as microbiology including the presence of Enterococcus species. The combined area under the receiver operating characteristics curve of the risk calculator for periprosthetic hip and knee joint reinfection was 0.75. Conclusions The study findings demonstrate that surgical factors, including previous PJI surgical treatment techniques as well as the number of previous surgeries, alongside microbiology including the presence of Enterococcus species have the strongest effect on the risk for periprosthetic THA and TKA joint reinfection, suggesting the limited applicability of the existing risk calculators for the development of PJI following primary TJA in predicting the risk of periprosthetic joint reinfection.

Background Obesity has been associated with complications after a total knee arthroplasty (TKA). Surgical site infection (SSI) after TKA is one of the feared complications as it increases revision rates, costs, and stress to the patient. There is conflicting evidence in the literature regarding body mass index (BMI) and risk of infection after TKA, and some studies have suggested that site-specific fat distribution may be a better metric for determining risk of postoperative infections. Here, we investigate the correlation of soft tissue distribution about the knee to SSI after TKA. Methods We retrospectively review 572 patients who underwent primary TKA at a single institution from 2006 to 2010. We introduce the prepatellar fat thickness ratio (PFTR) as a radiographic means to quantitatively assess fat distribution about the knee and evaluate this measurement’s ability to assess the risk of developing an SSI after TKA. Results The PFTR was shown to be a better predictor of SSI than BMI in both the univariate (P = .05) and multivariate (P = .01) analyses. Conclusion Although BMI cannot fully account for variations in adipose distribution, the PFTR may account for this variability and may be a helpful tool for assessing a patient’s preoperative risk of SSI after TKA.

We sought is to determine the mechanism of failure among primary total knee arthroplasties (TKAs) performed at a single high-volume institution by asking the following research questions: (1) What are the most common failure modes for modern TKA designs? and (2) What are the preoperative risk factors for failure following primary TKA?From May 2007 to December 2012, 18,065 primary TKAs performed on 16,083 patients at a single institution were recorded in a prospective total joint arthroplasty registry with a minimum of 5-year follow-up. We retrospectively reviewed patient charts to determine a cause of failure for primary TKAs. A cox proportional hazard model was used to determine the risk of revision surgery following primary TKA.The most common reasons for failure within 2 years after TKA were infection and stiffness. The multivariable regression identified the following preoperative risk factors for TKA failure: history of drug abuse (hazard ratio [HR] 4.68; P = 0.03), deformity/mechanical preoperative diagnosis (HR 3.52; P.01), having a constrained condylar knee implant over posterior-stabilized implant (HR 1.99; P.01), post-traumatic/trauma preoperative diagnosis (HR 1.78; P = .03), and younger age (HR 0.61; P.01) CONCLUSION: These findings add to the growing data that primary TKAs are no longer failing from polyethylene wear-related issues. This study identified preoperative risk factors for failure of primary TKAs, which may be useful information for developing strategies to improve outcomes following TKA.

Background Revision surgery of failed metal-on-metal (MoM) total hip arthroplasty (THA) for adverse tissue reaction (pseudotumor) can be challenging as a consequence of soft tissue and muscle necrosis. The aims of this study were to (1) report the revision outcomes of patients who underwent revision surgery for failed MoM hip arthroplasty due to symptomatic pseudotumor and (2) identify preoperative risk factors associated with revision outcomes. Methods Between January 2011 and January 2013, a total of 102 consecutive large head MoM hip arthroplasties in 97 patients (male: 62, female: 35), who underwent revision surgery were identified from the database of a multidisciplinary referral center. Results At minimum follow-up of 2 years (range: 26-52 months), at least one complication had occurred in 14 of 102 revisions (14%). Prerevision radiographic loosening ( P = .01), magnetic resonance imaging (MRI) findings of solid lesions with abductor deficiency on MRI ( P P = .05) were correlated with post-revision complications. The reoperation rate of revised MoM THA was 7% (7 of 102 hips). Implant survivorship was 88% at 3 years. Metal ion levels declined in most patients after removal of MoM articulation. Conclusion Revision outcomes of revision surgery for failed MoM THA due to symptomatic pseudotumor demonstrated 14% complication rate and 7% re-revision rate at 30-month follow-up. Our study identified prerevision radiographic loosening, solid lesions/abductor deficiency on MRI, and high grade intraoperative tissue damage as risk factors associated with poorer revision outcomes. This provides clinically useful information for preoperative planning and perioperative counseling of MoM THA patients undergoing revision surgery.

Background Anterior knee subcutaneous thickness has been associated with increased risk of early reoperation for surgical site infection after primary total knee arthroplasty (TKA) in morbidly obese patients. However, most patients undergoing TKA are not morbidly obese. The aims of this study were to (1) assess the association between anterior knee subcutaneous thickness and early superficial wound complications and (2) determine a threshold value for anterior knee subcutaneous thickness measures that can assist in preoperative risk stratification in nonmorbidly obese TKA patients. Methods Using retrospective analysis, we reviewed 494 primary TKAs performed in patients with a body mass index Results Sixty-two of the 494 patients developed a superficial wound complication within 90 days of index arthroplasty. TKA patients in the superficial wound complication group had significantly less pretubercular thickness (P = .027). Risk of developing 90-day superficial wound complication was 1.85-fold lower when pretubercular thickness was ≥12 mm (P = .028). Prepatellar thickness (P = .895) was not significantly associated with superficial wound complications. Conclusion Increased pretubercular thickness is a protective factor for developing superficial wound complications, with 12 mm being an ideal threshold value for preoperative risk stratification in nonmorbidly obese patients undergoing primary TKA surgery.

Background Reduced flexion after total knee arthroplasty (TKA) compared to the preoperative values can affect patient's activities of daily living and lead to patient dissatisfaction. The aim of this study was to determine preoperative risk factors for developing a decrease in knee flexion after a primary TKA. Methods We identified 37 knees diagnosed with osteoarthritis with a preoperative knee flexion ≥120° but a 12-month postoperative range of motion (ROM) ≤110°. A random sample of 111 patients (1:3) from the same database, whose knees had a preoperative and 12-month postoperative ROM ≥120°, based on a diagnosis of primary osteoarthritis and no previous open knee surgery, were selected as the controls. Results We found female gender, black ethnicity, and the low preoperative knee-specific Knee Society Score to be significant risk factors for developing a reduction of knee flexion after TKA with odds ratios of 3.48, 5.11, and 0.95, respectively. Conclusion In the absence of the well-recognized preoperative risk factors for a limited postoperative ROM, female patients, minorities, and those with lower knee-specific Knee Society Scores are at an increased risk of developing a decrease in flexion after an elective primary TKA.

The evaluation and management of outcomes risk has become an essential element of a modern total joint replacement program. Our multidisciplinary team designed an evidence-based tool to address modifiable risk factors for adverse outcomes after primary hip and knee arthroplasty surgery.Our protocols were designed to identify, intervene, and mitigate risk through evidence-based patient optimization. Nurse navigators screened patients preoperatively, identified and treated risk factors, and followed patients for 90 days postoperatively. We compared patients participating in our optimization program (N = 104) to both a historical cohort (N = 193) and a contemporary cohort (N = 166).Risk factor identification and optimization resulted in lower hospital length of stay (LOS) and postoperative emergency department (ED) visits. Patients in the optimization cohort had a statistically significant decrease in mean LOS as compared to both the historical cohort (2.55 vs 1.81 days, P.001) and contemporary cohort (2.56 vs 1.81 days, P.001). Patients in the optimization cohort had a statistically significant decrease in 30- and 90-day ED visits compared to the historical cohort (POptimization of patients before elective primary total hip arthroplasty and total knee arthroplasty reduced average LOS, ED visits, and drove telerehabilitation use. Our results add to the limited body of literature supporting this patient-centered approach.

This study's purpose was to assess the impact of a preoperative risk stratification program on joint arthroplasty outcomes at a single institution. We hypothesized that by using a standardized preoperative risk stratification center we would see better outcomes and decreased costs. The triage cohort (T) included 1498 patients assessed at a standardized risk stratification center, and the non-triage cohort (NT) included 1100 patients who did not utilize the center. The T cohort had significantly higher ASA classification (P

Fifty-six patients over the age of 80 undergoing revision hip arthroplasty in 57 hips were reviewed. The average age of the patients at the time of surgery was 81 years 6 months, and the mean follow-up period was 2 years 6 months. No complications were seen in 21 patients. The complications encountered in the others were medical in 35 and procedure-related in 15. The preoperative risk factor rating (American Society of Anesthesiologists classification) correlated very well with the incidence and grading of medical complications. This correlation was significant, emphasizing the importance of strict preoperative medical and anesthetic assessment in this group of patients. The mean d'Aubigne and Postel hip score improved from 2.8, 2.2., and 3.4 to 5.6, 4.8, and 4.9 after revision surgery.