The purpose of this randomized controlled trial was to evaluate serum metal ion levels in patients undergoing THA with either a standard or modular dual-mobility bearing. Patients undergoing primary THA for osteoarthritis were randomized to receive either a modular dual-mobility or a standard polyethylene bearing. All patients received the same titanium acetabular and femoral component and a ceramic femoral head. Only patients without a prior history of metal implants in their body were eligible for inclusion, thus isolating serum metal ions to the prosthesis itself. Serum metal ion levels were drawn pre-operatively and at 1 year postoperatively. Power analysis determined that 40 patients (20 in each group) were needed to identify a clinically relevant difference in serum cobalt of 0.35 ng/ml (ppb) at 90% power assuming a pooled standard deviation of 0.31 ppb and alpha=0.05; an additional 30% were enrolled to account for potential dropouts. 53 patients were enrolled, with 22 patients in the modular dual-mobility group and 20 in the standard cohort with data available at one-year. No differences in the serum cobalt (0.17 ppb [range 0.07 to 0.50] vs. 0.19 ppb [range 0.07 to 0.62], p = 0.51) or chromium levels (0.19 ppb [range 0.05 to 0.56] vs. 0.16 ppb [range 0.05 to 0.61], p = 0.23) were identified. At 1 year postoperatively, no differences in serum cobalt or chromium levels were identified with this design of a modular dual mobility bearing when compared to a standard polyethylene bearing.
The proportion of arthroplasties performed in the ambulatory setting has increased substantially. However, concerns remain regarding whether same-day discharge may increase the risk of complications. The purpose of this study was to compare 90-day outcomes between inpatients and patients having surgery at an ambulatory surgery center (ASC). Among a single-surgeon cohort of 721 patients who underwent arthroplasty at a free-standing ASC, 611 (84.7%) were matched one-to-one to inpatients based on age, gender, American Society of Anesthesiologists (ASA) score, and Body Mass Index (110 patients could not be adequately matched). The cohort included 208 total hip arthroplasties (34.0%), 196 total knee arthroplasties (32.1%), 178 unicompartmental knee arthroplasties (29.1%), 25 hip resurfacings (4.1%), two revision hip arthroplasties (0.3%) and two revision knee arthroplasties (0.3%). Post-operative outcomes including readmissions, reoperations, unplanned clinic visits, emergency department visits, and complications were compared. Complications were classified as either major (i.e. death, periprosthetic joint infection, pulmonary embolism) or as minor (i.e. delayed wound healing, rashes, urinary retention).Introduction
Methods
Surgical management of PJI remains challenging with patients failing treatment despite the best efforts. An important question is whether these later failures reflect reinfection or the persistence of infection. Proponents of reinfection believe hosts are vulnerable to developing infection and new organisms emerge. The alternative hypothesis is that later failure is a result of an organism that was present in the joint but was not picked up by initial culture or was not a pathogen initially but became so under antibiotic pressure. This multicenter study explores the above dilemma. Utilizing next-generation sequencing (NGS), we hypothesize that failures after two stage exchange arthroplasty can be caused by an organism that was present at the time of initial surgery but not isolated by culture. This prospective study involving 15 institutions collected samples from 635 revision total hip (n=310) and knee (n=325) arthroplasties. Synovial fluid, tissue and swabs were obtained intraoperatively for NGS analysis. Patients were classified per 2018 Consensus definition of PJI. Treatment failure was defined as reoperation for infection that yielded positive cultures, during minimum 1-year follow-up. Concordance of the infecting pathogen cultured at failure with NGS analysis at initial revision was determined.Introduction
Methods
The proportion of arthroplasties performed in the ambulatory setting has increased substantially. However, concerns remain regarding whether same-day discharge may increase the risk of complications. The purpose of this study was to compare 90-day outcomes between inpatients and patients having surgery at an ambulatory surgery center (ASC). Among a single-surgeon cohort of 721 patients who underwent arthroplasty at a free-standing ASC, 611 (84.7%) were matched one-to-one to inpatients based on age, gender, American Society of Anesthesiologists (ASA) score, and Body Mass Index (110 patients could not be adequately matched). The cohort included 208 total hip arthroplasties (34.0%), 196 total knee arthroplasties (32.1%), 178 unicompartmental knee arthroplasties (29.1%), 25 hip resurfacings (4.1%), two revision hip arthroplasties (0.3%) and two revision knee arthroplasties (0.3%). Post-operative outcomes including readmissions, reoperations, unplanned clinic visits, emergency department visits, and complications were compared. Complications were classified as either major (i.e. death, periprosthetic joint infection, pulmonary embolism) or as minor (i.e. delayed wound healing, rashes, urinary retention).Introduction
Methods
Wound complications following revision total hip arthroplasty (THA) are associated with an increased risk of superficial and deep infections. Closed incision negative-pressure therapy (ciNPT) has been reported to decrease this risk. This study's purpose was to assess if ciNPT decreases the rate of wound complications following revision THA versus a conventional, silver-impregnated dressing. This was a single center, randomized controlled trial of patients undergoing both septic and aseptic revision THA. Patients received either ciNPT or a silver-impregnated dressing (control) for 7 days. Wound complications within 90 days of the procedure were recorded, including: surgical site infection (SSI), periprosthetic joint infection (PJI), prolonged drainage greater than 5 days, erythema requiring antibiotics, and hematoma formation. An Introduction
Methods
Opioids are an important component of multimodal analgesia, but improper utilization places patients at risk for overdose and addiction. The purpose of this randomized controlled trial is to determine whether the quantity of opioid pills prescribed at discharge is associated with the total amount of opioids consumed or unused by patients after total hip (THA) and knee (TKA) arthroplasty. 304 Opioid naïve patients undergoing THA or TKA were randomized to receive a prescription for either 30 or 90 5mg oxycodone immediate release (OxyIR) tablets at discharge. All patients received acetaminophen, meloxicam, tramadol and gabapentin perioperatively. Daily opioid consumption, reported in morphine equivalent dose (MED), number of unused OxyIR, and pain scores were calculated for 30 days postoperatively with a patient-completed medication diary. The number of OxyIR refills and total MED received were recorded for 90 days postoperatively. Power analysis determined that 141 patients per group were necessary to detect a 25% reduction in means in opiate consumption between groups. Statistical analysis involved t-test, rank sum, and chi-squared tests with alpha=0.05.Introduction
Methods
Tranexamic acid (TXA) is proven to reduce blood loss following total knee arthroplasty (TKA), but there are limited data on the impact of similar dosing regimens in revision TKA that is associated with greater blood loss. The purpose of this multi-center randomized trial was to determine the optimal regimen to maximize the blood-sparing properties of TXA in revision TKA. 233 Septic and aseptic revision TKA from six-centers were randomized to either receive 1g pre-incision intravenous (IV) TXA, 1g pre- and post-incision IV TXA, 1g pre-incision IV and 1g intra-operative topical TXA, or three doses of 1950mg oral TXA given 2 hours pre-operatively, 6 hours post-operatively, and the morning of postoperative day 1. Randomization was performed based on type of revision to ensure equivalent distribution among groups. The primary outcome was reduction in hemoglobin. Power analysis determined 40 patients per group were necessary to identify a 1g/dL difference with an alpha of 0.05 and beta of 0.80. Per-protocol analysis involved regression analysis and two one-sided t-tests for equivalence.Introduction
Methods
This study explores whether subjects with bicruciate retaining TKRs (BiCR) have more normal knee biomechanics during level walking and stair ascent than subjects with posterior cruciate retaining TKRs (PCR). Due to anterior cruciate ligament (ACL) preservation, we expect BiCR subjects will not show the reduced flexion and altered muscle activation patterns characteristic of persons with TKRs. Motion and electromyography (EMG) data were collected during level walking and stair climbing for 16 BiCR subjects (4/12 m/f, 65±3 years, 30.7±7.0 BMI, 8/8 R/L), 17 PCR subjects (2/15 m/f, 65±7 years, 30.4±5.1 BMI, 7/10 R/L), and 17 elderly healthy control subjects (8/9 m/f, 55±10 years, 25.8±4.0 BMI, 10/7 R/L), using the point cluster marker set. Surface EMG electrodes were placed on the vastus medialis obliquus (VMO), rectus femoris (RF), biceps femoris (BF), and semitendinosus (ST) muscles. EMG data are reported as percent relative voluntary contraction (%RVC), normalized to the average peak EMG signals during level walking. Statistical nonparametric mapping was used for waveform analysis.Introduction
Methods
Bicruciate-retaining (BiCR) total knee replacements (TKRs) were designed to improve implant performance; however, functional advantages during daily activity have yet to be demonstrated. Although level walking is a common way to analyze functionality, it has been shown to be a weak test for identifying gait abnormalities related to ACL pathologies. The goal of this study is to set up a functional motion analysis test that will examine the effects of the ACL in TKR patients by comparing knee kinematics, kinetics, and muscle activation patterns during level and downhill walking for patients with posterior-cruciate retaining (PCR) and BiCR TKRs. Motion and electromyography (EMG) data were collected simultaneously for 12 subjects (4/8 m/f, 64±11 years, 31.3±7.3 BMI, 6/6 right/left) with BiCR TKRs and 15 subjects (6/9 m/f, 67±7 years, 30.5±5.1 BMI, 4/11 right/left) with PCR TKRs during level and downhill walking using the point cluster marker set. Surface electrodes were placed on the vastus medialis obliquus (VMO), rectus femoris (RF), biceps femoris (BF), and semitendinosus (ST) muscles. EMG data are reported as percent relative voluntary contraction (%RVC), normalizing the signal during downhill walking to the mean maximum EMG value during level walking.Introduction
Methods
