Do Ultraviolet Air Disinfection Units Reduce Contamination by Particulates in Total Knee Replacement Procedures?

BACKGROUND: Prosthetic joint infections have become the leading cause of joint replacement failure. The primary sources of contamination are skin flora and bacteria from airborne particles. Portable ultraviolet air disinfection units are used in the Operating Room (OR) to prevent contamination from airborne particles; however, their effectiveness is not proven. The purpose of this study was to compare the rate of contamination of sites with and without Ultraviolet (UV) air disinfection units during active surgeries. METHODS: Sedimentation rates of viable particles were measured during 40 primary TKA procedures. Half of the procedures were performed with ultraviolet air disinfection units. Air-borne particles were collected on nitrocellulose membranes at 5 locations within the OR. After incubation, all microbial colonies were counted and the sedimentation rates were reported in CFUs/m2/hr. 10 additional trials were performed in an empty OR with no staff present. RESULTS: The average contamination rate of all sites was 22 ± 1.1 CFUs/m2/hr in the empty OR vs. 21.3 ± 4.6 CFUs/m2/hr with UV units and 20.3 ± 4.9 CFUs/m2/hr without (P = .03, P = .03, P = .964). Viable contaminates were found in the sterile field in 25% of UV cases vs 45% non-UV. These differences were not statistically significant. There were differences found however, according to the number of staff in the room (6 vs 7 staff: P = .036, 6 vs 8 staff: P = .004). CONCLUSION: There was no statistical difference in contamination rate with the usage or non-usage of UV units. These 40 cases shows that the largest variables affecting the contamination rate were the number of staff present and size of the OR.

Humanitarian Needs: The Arthroplasty Community and the COVID-19 Pandemic.

BACKGROUND: As the world struggles with the COVID-19 pandemic, health care providers are on the front lines. We highlight the value of engaging in humanitarian medical work, contributions of the hip and knee arthroplasty community to date, and future needs after the resolution of the pandemic. We sought to understand how the arthroplasty community can contribute, based on historical lessons from prior pandemics and recessions, current needs, and projections of the COVID-19 impact. METHODS: We polled members of medical mission groups led by arthroplasty surgeons to understand their current efforts in humanitarian medical work. We also polled orthopedic colleagues to understand their role and response. Google Search and PubMed were used to find articles relevant to the current environment of the COVID-19 pandemic, humanitarian needs after previous epidemics, and the economic effects of prior recessions on elective surgery. RESULTS: Hip and knee arthroplasty surgeons are not at the center of the pandemic but are providing an invaluable supportive role through continued care of musculoskeletal patients and unloading of emergency rooms. Others have taken active roles assisting outside of orthopedics. Arthroplasty humanitarian organizations have donated personal protective equipment and helped to prepare their partners in other countries. Previous pandemics and epidemics highlight the need for sustained humanitarian support, particularly in poor countries or those with ongoing conflict and humanitarian crises. CONCLUSION: There are opportunities now to make a difference in this health care crisis. In the aftermath, there will be a great need for humanitarian work both here and throughout the world.

Robotics in Orthopedics: A Brave New World.

Future health-care projection projects a significant growth in population by 2020. Health care has seen an exponential growth in technology to address the growing population with the decreasing number of physicians and health-care workers. Robotics in health care has been introduced to address this growing need. Early adoption of robotics was limited because of the limited application of the technology, the cumbersome nature of the equipment, and technical complications. A continued improvement in efficacy, adaptability, and cost reduction has stimulated increased interest in robotic-assisted surgery. The evolution in orthopedic surgery has allowed for advanced surgical planning, precision robotic machining of bone, improved implant-bone contact, optimization of implant placement, and optimization of the mechanical alignment. The potential benefits of robotic surgery include improved surgical work flow, improvements in efficacy and reduction in surgical time. Robotic-assisted surgery will continue to evolve in the orthopedic field.

Implementation of Bundled Payment Initiatives for Total Joint Arthroplasty: Decreasing Cost and Increasing Quality.

Although the Bundled Payments for Care Improvement (BPCI) Initiative began generating data in January 2013, it may be years before the data can determine if the BPCI Initiative enhances value without decreasing quality. Private insurers have implemented other bundled payment arrangements for the delivery of total joint arthroplasty in a variety of practice settings. It is important for surgeons to review the early results of the BPCI Initiative and other bundled payment arrangements to understand the challenges and benefits of healthcare delivery systems with respect to total joint arthroplasty. In addition, surgeons should understand methods of cost control and quality improvement to determine the effect of the BPCI Initiative on the value-quality equation with respect to total joint arthroplasty.

Bundled Payment in Total Joint Care: Survey of AAHKS Membership Attitudes and Experience with Alternative Payment Models.

The goal of alternative payment models (APMs), particularly bundling of payments in total joint arthroplasty (TJA), is to incentivize physicians, hospitals, and payers to deliver quality care at lower cost. To study the effect of APMs on the field of adult reconstruction, we conducted a survey of AAHKS members using an electronic questionnaire format. Of the respondents, 61% are planning to or participate in an APM. 45% of respondents feel that a bundled payment system will be the most effective model to improve quality and to reduce costs. Common concerns were disincentives to operate on high-risk patients (94%) and uncertainty about revenue sharing (79%). While many members feel that APMs may improve value in TJA, surgeons continue to have reservations about implementation.

The economic significance of orthopaedic infections.

Musculoskeletal infections are a leading cause of patient morbidity and rising healthcare expenditures. The incidence of musculoskeletal infections, including soft-tissue infections, periprosthetic joint infection, and osteomyelitis, is increasing. Cases involving both drug-resistant bacterial strains and periprosthetic joint infection in total hip and total knee arthroplasty are particularly costly and represent a growing economic burden for the American healthcare system. With the institution of the Affordable Care Act, there has been an increasing drive in the United States toward rewarding healthcare organizations for their quality of care, bundling episodes of care, and capitating approaches to managing populations. In current reimbursement models, complications following the index event, including infection, are not typically reimbursed, placing the burden of caring for infections on the physician, hospital, or accountable care organization. Without the ability to risk-stratify patient outcomes based on patient comorbidities that are associated with a higher incidence of musculoskeletal infection, healthcare organizations are disincentivized to care for moderate- to high-risk patients. Reducing the cost of treating musculoskeletal infection also depends on incentivizing innovations in infection prevention.

Capturing orthopaedic surgical site infection data and assessing dental recommendations with respect to total joint arthroplasty.

Greater documentation of patient history and clinical course is crucial for identifying factors that can influence surgical outcomes. The Centers for Medicare and Medicaid Services have already begun public reporting of hospital data on readmission, complication, and infection rates and will soon launch a website to make physician-specific outcomes data public. The orthopaedic community has the opportunity to lead the way in ensuring that adequate and accurate data is collected to facilitate appropriate comparisons that are based on patients' true risk of complications and the complexity of treatment. Several studies have reported a link between oral pathogens and periprosthetic infection, although it remains unclear whether organisms unique to dental tissues are also present in osteoarthritic joints and tissues affected by periprosthetic joint infection. The American Academy of Orthopaedic Surgeons and the American Dental Association are aware of these concerns and have created guidelines for antibiotic prophylaxis in patients who have undergone total hip or knee arthroplasty and require high-risk dental procedures. Because these guidelines have received considerable criticism, recommendations that are based on scientific and case-controlled clinical studies and provide effective guidance on this important subject are needed.

Career plans of current orthopaedic residents with a focus on sex-based and generational differences.

BACKGROUND: An orthopaedic workforce shortage has been projected. The purpose of this study is to analyze the supply side of this shortage by ascertaining the career plans of current orthopaedic residents, comparing these plans with the career patterns of practicing orthopaedists, and identifying career-plan differences according to sex. METHODS: An online, self-administered survey was e-mailed to U.S. orthopaedic residents in postgraduate year three or higher, querying them about their fellowship specialty choice and their career plans. RESULTS: A total of 498 residents completed the online survey; 430 respondents (86%) were male, sixty-three (13%) were female, and five (1%) did not provide information regarding sex. Ninety-one percent of the residents were planning to enroll in a fellowship, with some respondents indicating more than one subspecialty choice: 28% intended to choose sports; 21%, arthroplasty; 14%, hand surgery, 12%, trauma; 8%, pediatrics; 8%, shoulder and elbow surgery; 8%, spine surgery; 6%, foot and ankle surgery; and 2%, oncology. With regard to the top career priorities of residents in selecting a fellowship specialty, 40% indicated intellectual priorities; 36%, educational; 21%, lifestyle; and 4%, economic. Significantly more women than men were planning on pursuing a pediatric fellowship (24% versus 6%, respectively, p < 0.05) and significantly fewer were planning on pursuing a sports fellowship (11% versus 31%, respectively, p < 0.05). Significantly more women than men planned on a subspecialty-only practice (62% versus 34%, respectively, p < 0.05). The projected retirement age of sixty-four years for current residents is roughly equal to that of the previous generation. There was no difference between men and women with regard to leadership and research aspirations, projected retirement age, and projected workdays per week. However, significantly more women than men (65% versus 47%, respectively) planned on reducing their work hours or changing to part-time status at some time during their careers. There is a higher percentage of female residents (13%) than female practicing orthopaedists (4%) in the United States. CONCLUSIONS: We should continue efforts to collect workforce data and be proactive to avert or minimize the effect of impending orthopaedic workforce shortages on our patients. Given the trend toward an increasing proportion of female orthopaedists and the higher likelihood that they will reduce their work hours during portions of their career, policymakers should consider training more orthopaedists to ensure patient access to timely, quality orthopaedic care.

Does greater knee flexion increase patient function and satisfaction after total knee arthroplasty?

The purpose of this study was to determine whether high flexion leads to improved benefits in patient satisfaction, perception, and function after total knee arthroplasty (TKA). Data were collected on 122 primary TKAs. Patients completed a Total Knee Function Questionnaire. Knees were classified as low (≤ 110°), mid (111°-130°), or high flexion (>130°). Correlation between knee flexion and satisfaction was not statistically significant. Increased knee flexion had a significant positive association with achievement of expectations, restoration of a "normal" knee, and functional improvement. In conclusion, although the degree of postoperative knee flexion did not affect patient satisfaction, it did influence fulfillment of expectations, functional ability, and knee perception. This suggests that increased knee flexion, particularly more than 130°, may lead to improved outcomes after TKA.

A resident survey study of orthopedic fellowship specialty decision making and views on arthroplasty as a career.

A dramatic shortage of total hip arthroplasty (THA) and total knee arthroplasty (TKA) surgeons has been projected because fewer residents enter arthroplasty fellowships, and the demand for THAs/TKAs is rising. The purposes of this study were to ascertain the future supply of THA/TKA surgeons, to identify the criteria residents use to choose their fellowship specialty, and to assess resident perceptions of an arthroplasty career. Four hundred ninety-eight post-graduate year 3 and above residents completed the online survey. Residents most highly prioritize intellectual factors and role models/mentors in determining their fellowship specialty. In the face of a looming patient access-to-care crisis, the data from this study support a policy of highlighting the intellectual challenges and satisfaction of THA/TKA as a career and encouraging mentorship early in a resident's training.

Influence of gender on age of treatment with TKA and functional outcome.

BACKGROUND: Previous studies suggest differences may exist between men and women in terms of knee function before and after total knee replacement. This may be related to the efficacy of the procedure itself or to differences in the severity of disability of male and female patients at the time of surgery. QUESTIONS/PURPOSES: We evaluated differences in the age, preoperative deformity, range-of-motion, and Knee Society scores of men and women who underwent TKA. All parameters were measured at the time of the initial preoperative evaluation and at postoperative followup. METHODS: We studied 698 patients who underwent elective TKA between 1996 and 2007. This population consisted of 428 women (61%) and 270 men (39%), all of whom underwent rehabilitation utilizing a standardized hyperflexion protocol with immediate initiation of full weight-bearing postoperatively. RESULTS: The men were on average three years younger than the women (mean 63.5 versus 66.6 years, respectively). Preoperative ROM, postoperative ROM, and changes in ROM and body mass index were similar between groups. Knee Society Knee scores were similar preoperatively (47.4 [men] versus 46.7 [women]), but four points higher in men at followup (89.2 versus 85.2). Women had lower Knee Function scores than men preoperatively (45.2 versus 57.1), and postoperatively (65.3 versus 73.9). CONCLUSIONS: Women who undergo TKA seek treatment at a later stage than men and have greater functional disability at the time of surgery. Differences in functional scores persist after TKA. Earlier initiation of treatment may enhance postoperative outcome. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Implant durability and knee function after total knee arthroplasty in the morbidly obese patient.

This study investigated the effect of body mass index (BMI) on outcomes after cemented tricompartmental total knee arthroplasty (TKA). Functional and radiographic Knee Society scores in 71 patients (94 knees) with BMI 30 to 39 and 31 patients (41 knees) with BMI > or =40 were compared with 67 patients (85 knees) with BMI 20 to 29 at a mean follow-up of 5.4 years. Total knee arthroplasty rates of success (79%), complication (17%), and revision (6%) were independent of BMI. The BMI > or =40 group, however, was 5.4x (95% confidence interval, 2.1-14.7) more likely to develop patellar radiolucencies, had poorer hamstring and quadriceps conditioning, and had more patellofemoral symptoms. Forty percent of TKAs at BMI > or =40 with patellar radiolucencies failed. In conclusion, TKA benefits were realized at all BMI, but at BMI > or =40, more rehabilitation and monitoring are recommended.

Current practices of AAHKS members in the treatment of adult osteonecrosis of the femoral head.

BACKGROUND: There is currently no standardized protocol for evaluating and treating osteonecrosis of the femoral head in adults in the United States. We sought to understand current treatment practices of a group of surgeons who commonly treat this disease to determine if there was agreement on some aspects of care. METHODS: We designed a two-staged mixed-mode (mailed and faxed) sixteen-question self-administered descriptive survey questionnaire to be sent to all 753 active members of the American Association of Hip and Knee Surgeons (AAHKS). The survey design was based on Dillman's survey research methodology, and the questionnaire included hypothetical clinical scenarios based on the Steinberg classification system. The responses elucidated the opinions and treatment preferences of high-volume arthroplasty surgeons who treat adult patients with osteonecrosis of the femoral head. RESULTS: Of the 753 active members of the AAHKS, 403 (54%) responded to the questionnaire. Total hip replacement was reported to be the most frequent intervention for treatment of postcollapse (Steinberg stage-IIIB, IVB, V, and VI) osteonecrosis; core decompression was reported to be the most commonly offered intervention for symptomatic, precollapse (Steinberg stage-IB and IIB) osteonecrosis. Less frequently offered treatments included nonoperative management, osteotomy, vascularized and non-vascularized bone-grafting, hemiarthroplasty, and arthrodesis. CONCLUSIONS: The care of adults with osteonecrosis of the femoral head varies among American orthopaedic surgeons specializing in hip and knee surgery. A consensus may evolve with a continued concerted effort on the part of interested surgeons, but it will require randomized, controlled, prospective studies of treatment of each stage of the disease and collaborative multicenter studies. LEVEL OF EVIDENCE: Therapeutic Level V.

Posterior cruciate ligament substitution is not essential for excellent postoperative outcomes in total knee arthroplasty.

The study compared postoperative range of motion (ROM) and functional outcome of total knee arthroplasty (TKA) with a posterior cruciate ligament (PCL)-substituting knee prosthesis compared with an ultracongruent PCL-sacrificing design. Two hundred nine patients underwent primary TKA. Posterior stabilized design (121) and highly conforming, PCL-sacrificing, ultracongruent design (88) TKAs were reviewed. Surgeon, surgical approach, and a hyperflexion postoperative rehabilitation protocol were the same. Results showed significant improvement in knee flexion, ROM, Knee Score, and Function Score within each group. Postoperative mean total ROM was slightly higher with the posterior stabilized design. The 2 groups were the same postoperatively in the improvement in ROM, Knee Score, Function Score, satisfaction level, among other activity metrics. There was no clear evidence proving superiority and the need for posterior stabilization in PCL-sacrificing TKA.

Surface damage of patellar components used in total knee arthroplasty.

BACKGROUND: Patellofemoral complications are a common cause of failure of total knee replacement. In this study, we examined eighty-five patellar components that had been retrieved for a variety of reasons after a mean of 71.9 months in vivo. The objective of this study was to identify factors contributing to surface damage of patellar components in total knee replacements. METHODS: The retrieved patellar components were of three primary designs: dome-shaped, sombrero-shaped, and pseudo-anatomic. Five zones on each specimen were evaluated for five different types of damage (creep, pitting, delamination, abrasion, and burnishing). The severity of the damage was assigned a score of 0 to 4, with 0 indicating no damage and 4 indicating extreme damage. The extent of the damage was also assigned a score of 0 to 4, with 0 indicating 0% and 4 indicating 76% to 100%. An asymmetry ratio was calculated for each damage pattern to evaluate the uniformity of the distribution of the damage across each component. RESULTS: Eighty-six percent of the components had a damage score of > or =4 (product of the extent and severity scores) for at least one damage mechanism (creep for 38% of the components, pitting for 47%, delamination for 26%, abrasion for 49%, and burnishing for 76%). Components that had been in situ for more than two years had significantly more severe creep, delamination, and burnishing than components that had been in place for less than two years. Metal-backed designs had more severe damage than all-polyethylene components. Factors that reduced the occurrence and severity of polyethylene damage were a congruent patellar design (a non-dome-shaped component) and the use of an asymmetric femoral component. CONCLUSIONS: Damage to the patellar component was a common finding, particularly when the implant had been retrieved more than two years after implantation. Moreover, delamination was frequently found on the patellar components, as has been observed by others who examined retrieved tibial inserts. The results of this study suggest that the use of congruent patellar components may reduce damage.

The PCL significantly affects the functional outcome of total knee arthroplasty.

This study tests the hypothesis that patients receiving a posterior cruciate ligament (PCL)-retaining prosthesis have no difference in functional outcome compared to those receiving a cruciate-sacrificing, posterior-stabilized (PS) design. Forty-nine patients underwent a total knee arthroplasty (TKA), performed by a single surgeon using the same implant design with either a PCL-retaining or a PS tibial insert. Each patient completed a self-administered, validated Total Knee Function Questionnaire as well as the SF-36. At 1-year follow-up, each patient's range of motion and Knee Society knee score were measured. There were no statistically significant differences between the 2 groups using the traditional measures of function following total knee replacement, including overall satisfaction with surgery. However, the TKFQ revealed that patients with PS knees reported greater functional limitations in squatting, kneeling, and gardening. Our results suggest that with the specific implant used in this study, substitution for the PCL with a spine and cam mechanism may not fully restore the functional capacity of the intact PCL, particularly in high-demand activities that involve deep flexion.

The optimal strategy for stable tibial fixation in revision total knee arthroplasty.

In revision total knee arthroplasty, the optimal strategy for stabilizing the tibial component in the face of proximal defects remains controversial. The stability of a revision tibial prosthesis was measured using a mechanical surrogate of the revision tibia, while varying the defect treatment proximally and the cortical engagement distally. An offset axial load in combination with an axial torque were applied to each specimen to simulate the stance phase of gait. It was found that, in revision total knee arthroplasty, the mechanical stability of tibial fixation is increased by the addition of a canal filling stem, especially in the presence of poor proximal bone. Proximal tibial coverage, even with a custom-fitted tibial component, adds little additional stability to a tibial tray stabilized by intramedullary engagement of a canal-filling stem.