Faculty Bibliography

BACKGROUND: Total knee arthroplasty (TKA) is often the best answer for end-stage, posttraumatic osteoarthritis after intra-articular and periarticular fractures about the knee. Although TKA in this setting is often considered more technically demanding, outcomes are typically worse for patients. This study examines the intraoperative differences and 30-day outcomes in posttraumatic vs primary TKA cohorts. METHODS: Patients undergoing TKA were selected from the National Surgical Quality Improvement Program database from 2010 to 2013. Patients were stratified on the basis of concurrent procedures and administrative codes indicating posttraumatic diagnoses. Thirty-day complications were recorded, and multivariate analyses were performed to determine whether posttraumatic arthritis was a risk factor for poor outcomes. RESULTS: A total of 67,675 primary and 674 posttraumatic TKAs were identified. Posttraumatic TKA patients were on average younger and healthier than the primary TKA population. The posttraumatic TKA group had higher rates of superficial surgical site infections and bleeding requiring transfusion. History of posttraumatic knee osteoarthritis was found to be an independent risk factor for prolonged operative time, increased length of hospital stay, and 30-day hospital readmission. CONCLUSION: We have demonstrated increased intraoperative times, heightened transfusion requirements and surgical site infections, and higher readmission rates after conversion TKA in the posttraumatic cohort. In contrast to total hip arthroplasty, current diagnosis and reimbursement schemes do not differentiate posttraumatic patients from primary osteoarthritis groups undergoing TKA. We believe that classification reform would improve medical documentation and improve patient care.

BACKGROUND: Periprosthetic joint infection (PJI) is one of the most common causes of revision total hip arthroplasty (THA) and associated with higher costs, prolonged pain, and worse clinical outcomes. Many factors have been linked to increased infection rates, one being the operative equipment and instrumentation used during the surgical procedure. With few arthroplasty instruments designed for complete disassembly and increasingly complex instrument designs, this study seeks to understand the effect that instrument disassembly plays on infection using disassembled and assembled standard femoral broach handles (BHs). METHODS: Two BHs, not designed for disassembly, were modified and then contaminated in the disassembled state with Geobacillus stearothermophilus vegetative-form bacteria and spores. Using both flash and standard sterilization cycles, the BHs were steam sterilized in the disassembled or assembled state and then analyzed for remaining bacteria and spores. RESULTS: At all target locations after either a flash sterilization cycle or a standard sterilization cycle, complete eradication of both the vegetative-form and spore-form of G stearothermophilus was achieved. CONCLUSION: This study demonstrates that adequate decontamination of the tested BHs can be achieved after steam sterilization in either the disassembled or assembled state, without an increased risk of infection transmission.

BACKGROUND: Expenditures for postacute care in total joint arthroplasty (TJA) have risen dramatically over recent decades. Therefore, efforts are underway to better identify cost savings in postacute rehabilitation centers, such as skilled nursing facilities (SNFs). The primary purpose of this study was to analyze gait training achievements in post-TJA patients in the interval between hospital discharge and the patients' first 4 days at the SNF. Identification of potential losses in therapeutic progress may lead the way for improved patient care, outcomes, and cost savings. Our hypothesis is that patients discharged to an SNF will have a decline in gait achievements upon transfer from the hospital. METHODS: A total of 68 patients who underwent TJA were included. The total distance ambulated during physical therapy (PT) was recorded for the last day of hospital therapy and the first 4 days at the SNF as well as the reported visual analog scale (VAS) pain scores. RESULTS: There was a 73% decline in distance ambulated on SNF day 0 (Hospital: 138.6 ft vs SNF: 37.9 ft; P < .001) and a 50% decline on SNF day 1 (Hospital: 103.0 ft; SNF vs 51.1 ft; P < .001) compared to the last hospital session. There were no significant differences in distance walked on SNF days 3 and 4 relative to the last hospital session. The VAS pain scores did not significantly differ on SNF days 0 and 1 compared to the last hospital day but began to significantly decline on SNF day 3 (Hospital: 4.9; SNF: 3.3; P = .02) and day 4 (Hospital: 3.9; SNF: 2.3; P = .03). CONCLUSION: There was a significant decline in ambulatory proficiency in post-TJA patients on the day of and the day following hospital discharge to an SNF. These deficits cannot be attributed to heightened pain levels. Early and progressive ambulation is a recognized component of appropriate PT following TJA. This study therefore highlights the transition from hospital to SNF as a crucial and novel target for improvement in post-TJA care.

BACKGROUND: Postoperative pain after total knee arthroplasty (TKA) poses a major challenge. It delays mobilization, increases opioid consumption and side effects, and lengthens hospitalization. This challenge multiplies when treating an opioid-dependent population. We examined whether a novel suspended release local anesthetic, liposomal bupivacaine (LB) would improve pain control and decrease opioid consumption after TKA compared to a standard periarticular injection in opioid-dependent patients. METHODS: Thirty-eight patients undergoing TKA were randomly assigned to receive either a periarticular injection (PAI) with LB (n = 20) or with a standard PAI (including a combination of ropivacaine, clonidine, Toradol, Epinepherine, and saline; n = 18) as part of a multimodal pain management approach. All periarticular injections were done by a single surgeon. Perioperative treatment was similar between groups. Postoperative information regarding pain level was evaluated by a pain visual analog scale score. Postoperative opioid consumption was recorded. RESULTS: After controlling baseline narcotic usage before surgery, no differences were found between groups in daily postoperative narcotic usage (P = .113), average daily pain score (P = .332), or maximum daily pain score (P = .881). However, when examining pain levels separately for each day, pain visual analog scale scores were reported higher in post operative day 1 in the LB group (P = .033). CONCLUSIONS: LB was not found to be superior to standard PAI in opioid-dependent patients undergoing TKA. This patient population continues to present a challenge even with modern multimodal pain protocols.

The ratio of anteroposterior (AP) to medial-lateral (ML) dimensions of the distal femur in adults differs by sex. The average AP/ML dimension ratios are 0.82 for females and 0.79 for males. How and when this difference develops is not yet understood. In this study, the distal femoral dimensions and physeal development of 345 participants younger than 21 years of age were evaluated by MRI. Regression analysis indicated a significant increase in the AP/ML ratio with increasing age for both sexes. In girls, the ratio increased from 0.63 at ages 0-5 years to 0.76 at 15-20 years. In boys, the ratio increased from 0.61 to 0.73 over the same age groups. Female distal femur dimensions are narrower than that of males from birth. Throughout childhood, both sexes show gradual increases in AP/ML ratios. After closure of the physes, the AP/ML ratio in children approaches adult values, with females continuing to have relatively narrower dimensions than males.

BACKGROUND: Although total knee arthroplasty (TKA) is associated with improved patient-reported function, pain, and quality of life, the effects on weight loss are less certain. In this study, we use data from a large, prospective cohort study of osteoarthritis (OA) patients to compare the changes in body mass index (BMI) across 6 years in OA patients who received TKA compared with OA patients who did not receive TKA. METHODS: Using data from the Osteoarthritis Initiative, a prospective cohort study of patients with OA, our study divided patients into two groups: patients who received a TKA during the Osteoarthritis Initiative study (N = 140) and those who did not (N = 697). The initial BMI, final BMI, and change in weight over 72 months were compared between groups. Subgroup analysis was performed by dividing patients by their initial BMI, gender, and age. RESULTS: The TKA group's change in weight, initial BMI, and final BMI were not significantly different from the non-TKA group over 72 months (weight change: -0.763 kg vs +0.191 kg; P = .597). Subgroups of women and patients aged 51-60 years with TKA gained more weight than respective non-TKA OA patients. CONCLUSIONS: Overall, patients who received TKA did not lose or gain more weight than OA patients who did not receive TKA. Patients with longer follow-up after TKA (>2 years) still gained weight on average. Despite the improved patient-reported pain levels, function, and quality of life after TKA, it appears that TKA alone is not a sufficient intervention for obesity.

BACKGROUND: With increasing health care expenditures, reform has largely focused on cost containment, particularly in elective procedures such as total hip and knee arthroplasty (THA and TKA, respectively). The primary objective of this study is to determine what financial value patients place on these highly successful procedures. METHODS: An anonymous survey was administered to 670 patients at 4 different institutions (2 private practice and 2 academic centers) in the outpatient setting over a 15-month period. Patients were asked what reimbursement a surgeon should receive for a primary total joint arthroplasty (TJA), their perception of how much Medicare actually reimburses for TJA, how much they would pay out of pocket for the procedure, and their opinion of current Medicare reimbursement rates. RESULTS: Of the 557 patients who participated in the survey (83% response rate), patients on average felt that orthopedic surgeons should be reimbursed $27,430 for a THA and $19,830 for a TKA. Patients would be willing to pay a significant amount of out-of-pocket costs for their procedure, mean of $14,397 for THA (50.3% of total costs) and $12,797 for TKA (46.3% of total costs). Although patients in private practice groups had higher education and household income (P < .001), patients in academic centers would be willing to pay more out-of-pocket costs ($15,922 vs $5782, P = .034 for THA, $14,419 vs $4556, P = .052 for TKA). CONCLUSION: Patients in both private practice and academic centers feel that surgeons are underpaid for primary THA and TKA. As controversy continues to surround orthopedic surgeons' participation in Medicare, many patients are still willing to pay a significant amount of out-of-pocket expenses for TJA.

INTRODUCTION: The clinical relevance of limb length discrepancy (LLD) after total hip arthroplasty gains attention as the number of total hip arthroplasties increases. Although several techniques are commonly used to assess LLD using a pelvic radiograph, their accuracy is not well established. This study measures LLD using different techniques viewing the pelvis and compares the measurements with the true LLD. METHOD: Pelvic landmarks used included the femoral head, lesser trochanter, acetabular teardrop, ischial tuberosity, and tibial plafond. The true LLD was determined by finding the difference in distance between the lowest point of the ischial tuberosity and the tibial plafond as well as the top of the femoral head to the center of the tibial plafond for each lower limb. RESULTS: Using pelvic landmarks to assess LLD is significantly different (P < .001) from the true LLD. The difference in distance from the center of the tibial plafond to the ischial tuberosity was not significantly different from the measurement from the top of the femoral head to the center of the tibial plafond (P = .08). Also, using the acetabular teardrop as a landmark has less reliability when compared to the ischial tuberosity. DISCUSSION: Owing to the extensive variety of pathologies that are associated with LLD, preoperative planning should include an assessment of any preexisting LLD. Although it may be reasonable to compare pelvic measurements preoperatively and postoperatively to assess for changes, the data from this study do not support the estimation of the true LLD using a pelvic radiograph.

Total hip arthroplasty (THA) is an increasingly common procedure among elderly individuals. Although conversion THA is currently bundled in a diagnosis related group (DRG) with primary THA, no study has identified whether conversion THA better resembles a primary or revision THA. The American College of Surgeons National Surgical Quality Improvement Project database was queried to identify 2009 conversion THA, 67,854 primary THA, and 5,089 revision THA procedures between 2009 and 2014. Univariate analysis was used to compare fifty-three preoperative, intraoperative, and postoperative variables. Seventeen variables demonstrated a statistical difference between conversion and primary THA without a corresponding difference between conversion and revision THA. Only one variable demonstrated a difference between conversion and revision THA without a similar difference between conversion and primary THA. This imbalance suggests that conversion THA better resembles revision THA characteristics, and that these procedures should be reclassified in the same DRG as revision THA instead of primary THA.

BACKGROUND: Effective use of prophylactic antibiotics decreases the incidence of surgical site infections (SSIs) after total joint arthroplasty (TJA). The purpose of this prospective study was to determine the viability of weight-based dosing protocols for cefazolin and vancomycin to determine if appropriate minimum inhibitory concentrations (MIC) are met. METHODS: Trabecular bone was harvested from discarded bone samples from 34 patients undergoing total knee arthroplasty (TKA) and total hip arthroplasty (THA). The cefazolin and vancomycin concentrations were determined in the trabecular bone using high-performance liquid chromatography. RESULTS: No difference was noted in bone concentration with respect to patient weight for cefazolin. Regarding vancomycin, a substantial difference was noted in trabecular bone concentrations with respect to patient weight with lower body mass index (BMI) achieving greater concentrations. Using the current weight-based protocol of antibiotic prophylaxis, 84% and 87% of patients receiving vancomycin and cefazolin, respectively, achieved bone concentrations above the MIC. CONCLUSIONS: Our assessment of trabecular concentration of cefazolin during TJA did not show any differences with respect to patient weight. However, vancomycin concentrations did show a difference with respect to BMI but this may be the result of the specific weight-based dosing protocol of vancomycin. Whereas the majority of cases were able to achieve adequate antibiotic concentrations in bone, further studies may be required to determine if increasing the pre-operative dosage of antibiotics is mandated given the findings of this pilot study.