Adolph J. Yates

Chemoattraction of Progenitor Cells by Remodeling Extracellular Matrix Scaffolds

The chemotactic properties of a biologic scaffold composed of extracellular matrix (ECM) and subjected to in vivo degradation and remodeling were evaluated in a mouse model of Achilles tendon reconstruction. Following a segmental resection of the Achilles tendon in both C57BL/6 and MRL/MpJ mice, the defect was repaired with either an ECM scaffold composed of urinary bladder matrix (UBM) or resected autologous tendon. The surgically repaired and the contralateral tendons were harvested at 3, 7, and 14 days following surgery from each animal. Chemotaxis of multipotential progenitor cells toward the harvested tissue was quantified using a fluorescent-based cell migration assay. Results showed greater migration of progenitor cells toward tendons repaired with UBM-ECM scaffold compared to both the tendons repaired with autologous tissue and the normal contralateral tendon in both the MRL/MpJ and C57BL/6 mice. The magnitude and temporal pattern of the chemotactic response differed between the two mouse strains.

Obesity and total joint arthroplasty. A literature based review

The prevalence of obesity in the population is unlikely to decline, and is likely to contribute to the increasing demand for hip or knee arthroplasty. Conflicting data exist on the risk and benefits of total joint arthroplasty in obese patients. The purpose of this manuscript is to define and identify areas of concern for obese patients undergoing total joint arthroplasty. A workgroup of total joint arthroplasty surgeons from the American Association of Hip and Knee Surgeons (AAHKS) was tasked with identifying key questions regarding obesity and total joint arthroplasty. The workgroup evaluated the available literature and sought to create a review regarding obesity and total joint arthroplasty to complement and guide the surgeon-patient discussion in addition to identifying areas of future research.

American Academy of Orthopaedic Surgeons clinical practice guideline on: preventing venous thromboembolic disease in patients undergoing elective hip and knee arthroplasty.

AAOS Guideline on Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty Summary of Recommendations The following is a summary of the recommendations of the AAOS’ clinical practice guideline, Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty. This summary does not contain rationales that explain how and why these recommendations were developed, nor does it contain the evidence supporting these recommendations. All readers of this summary are strongly urged to consult the full guideline and evidence report for this information. We are confident that those who read the full guideline and evidence report will see that the recommendations were developed using systematic evidence-based processes designed to combat bias, enhance transparency, and promote reproducibility. This summary of recommendations is not intended to stand alone. Treatment decisions should be made in light of all circumstances presented by the patient. Treatments and procedures applicable to the individual patient rely on mutual communication between patient, physician, and other healthcare practitioners. We recommend against routine post-operative duplex ultrasonography screening of patients who undergo elective hip or knee arthroplasty. (Grade of Recommendation: Strong) Patients undergoing elective hip or knee arthroplasty are already at high risk for venous thromboembolism. The practitioner might further assess the risk of venous thromboembolism by determining whether these patients had a previous venous thromboembolism. (Grade of Recommendation: Weak) Current evidence is not clear about whether factors other than a history of previous venous thromboembolism increase the risk of venous thromboembolism in patients undergoing elective hip or knee arthroplasty and, therefore, we cannot recommend for or against routinely assessing these patients for these factors. (Grade of Recommendation: Inconclusive) Patients undergoing elective hip or knee arthroplasty are at risk for bleeding and bleeding-associated complications. In the absence of reliable evidence, it is the opinion of this work group that patients be assessed for known bleeding disorders like hemophilia and for the presence of active liver disease which further increase the risk for bleeding and bleeding-associated complications. (Grade of Recommendation: Consensus) Current evidence is not clear about whether factors other than the presence of a known bleeding disorder or active liver disease increase the chance of bleeding in these patients and, therefore, we are unable to recommend for or against using them to assess a patients risk of bleeding. (Grade of Recommendation: Inconclusive) We suggest that patients discontinue antiplatelet agents (e.g., aspirin, clopidogrel) before undergoing elective hip or knee arthroplasty. (Grade of Recommendation: Moderate) We suggest the use of pharmacologic agents and/or mechanical compressive devices for the prevention of venous thromboembolism in patients undergoing elective hip or knee arthroplasty, and who are not at elevated risk beyond that of the surgery itself for venous thromboembolism or bleeding. (Grade of Recommendation: Moderate) Current evidence is unclear about which prophylactic strategy (or strategies) is/are optimal or suboptimal. Therefore, we are unable to recommend for or against specific prophylactics in these patients. (Grade of Recommendation: Inconclusive) In the absence of reliable evidence about how long to employ these prophylactic strategies, it is the opinion of this work group that patients and physicians discuss the duration of prophylaxis. (Grade of Recommendation: Consensus) In the absence of reliable evidence, it is the opinion of this work group that patients undergoing elective hip or knee arthroplasty, and who have also had a previous venous thromboembolism, receive pharmacologic prophylaxis and mechanical compressive devices. (Grade of Recommendation: Consensus) In the absence of reliable evidence, it is the opinion of this work group that patients undergoing elective hip or knee arthroplasty, and who also have a known bleeding disorder (e.g., hemophilia) and/or active liver disease, use mechanical compressive devices for preventing venous thromboembolism. (Grade of Recommendation: Consensus) In the absence of reliable evidence, it is the opinion of this work group that patients undergo early mobilization following elective hip and knee arthroplasty. Early mobilization is of low cost, minimal risk to the patient, and consistent with current practice. (Grade of Recommendation: Consensus) We suggest the use of neuraxial (such as intrathecal, epidural, and spinal) anesthesia for patients undergoing elective hip or knee arthroplasty to help limit blood loss, even though evidence suggests that neuraxial anesthesia does not affect the occurrence of venous thromboembolic disease. (Grade of Recommendation: Moderate) Current evidence does not provide clear guidance about whether inferior vena cava (IVC) filters prevent pulmonary embolism in patients undergoing elective hip and knee arthroplasty who also have a contraindication to chemoprophylaxis and/or known residual venous thromboembolic disease. Therefore, we are unable to recommend for or against the use of such filters. (Grade of Recommendation: Inconclusive)

Preoperative Screening/Decolonization for Staphylococcus aureus to Prevent Orthopedic Surgical Site Infection Prospective Cohort Study With 2-Year Follow-Up

We quantified surgical site infections (SSIs) after preoperative screening/selective decolonization before elective total joint arthroplasty (TJA) with 2-year follow-up and 2 controls. Concurrent controls (n = 2284) were patients of surgeons not participating in screening/decolonization. Preintervention controls (n = 741) were patients of participating surgeons who underwent TJA the previous year. Staphylococcus aureus nasal carriers (321/1285 [25%]) used intranasal mupirocin and chlorhexidine baths as outpatients. Staphylococcal SSIs occurred in no intervention patients (0/321) and 19 concurrent controls. If all SSIs occurred in carriers and 25% of controls were carriers, staphylococcal SSI rate would have been 3.3% in controls (19/571; P = .001). Overall SSI rate decreased from 2.7% (20/741) in preintervention controls to 1.2% (17/1440) in intervention patients (P = .009). Preoperative screening/selective decolonization was associated with fewer SSIs after elective TJA.

Preventing venous thromboembolic disease in patients undergoing elective hip and knee arthroplasty.

This guideline supersedes a prior one from 2007 on a similar topic. The work group evaluated the available literature concerning various aspects of patient screening, risk factor assessment, and prophylactic treatment against venous thromboembolic disease (VTED), as well as the use of postoperative mobilization, neuraxial agents, and vena cava filters. The group recommended further assessment of patients who have had a previous venous thromboembolism but not for other potential risk factors. Patients should be assessed for known bleeding disorders, such as hemophilia, and for the presence of active liver disease. Patients who are not at elevated risk of VTED or for bleeding should receive pharmacologic prophylaxis and mechanical compressive devices for the prevention of VTED. The group did not recommend specific pharmacologic agents and/or mechanical devices. The work group recommends, by consensus opinion, early mobilization for patients following elective hip and knee arthroplasty. The use of neuraxial anesthesia can help limit blood loss but was not found to affect the occurrence of VTED. No clear evidence was established regarding whether inferior vena cava filters can prevent pulmonary embolism in patients who have a contraindication to chemoprophylaxis and/or known VTED.

Measuring the Attitudes and Impact of the Eighty-Hour Workweek Rules on Orthopaedic Surgery Residents

BACKGROUND The literature on graduate medical education contains anecdotal reports of some effects of the new eighty-hour workweek on the attitudes and performance of residents. However, there are relatively few studies detailing the attitudes of large numbers of residents in a particular surgical specialty toward the new requirements. METHODS Between July and November 2004, a survey created by the Academic Advocacy Committee of the American Academy of Orthopaedic Surgeons was distributed by mail, fax, and e-mail to a total of 4207 orthopaedic residents at the postgraduate year-1 through year-6 levels of training. The survey responses were tabulated electronically, and the results were recorded. RESULTS The survey response rate was 13.2% (554 residents). Sixty-eight percent (337) of the 495 respondents whose postgraduate-year level was known were at the postgraduate year-4 level or higher. Attitudes concerning the duty rules were mixed. Twenty-three percent of the 554 respondents thought that eighty hours constituted an appropriate number of duty hours per week; 41% believed that eighty hours were too many, and 34% thought that eighty hours were not sufficient. Thirty-three percent of the respondents had worked greater than eighty hours during at least a single one-week period since the new rules were implemented; this occurred more commonly among the postgraduate year-3 and more junior residents. Orthopaedic trauma residents had the most difficulty adhering to the new duty-hour restrictions. Eighty-two percent of the respondents indicated that their residency programs have been forced to make changes to their call schedules or to hire ancillary staff to address the rules. The use of physician assistants, night-float systems, and so-called home-call assignments were the most common strategies used to achieve compliance. CONCLUSION Resident attitudes toward the work rules are mixed. The rules have forced residency programs to restructure. Junior residents have more favorable attitudes toward the new standards than do senior residents. Self-reporting of duty hours is the most common method of monitoring in orthopaedic training programs. Such systems allow ample opportunity for inaccuracies in the measurement of hours worked. Although residents report an improved quality of life as a result of these new rules, the attitude that the quality of training is diminished persists.

Modern metal-on-metal hip implants

This Technology Overview was prepared using systematic review methodology and summarizes the findings of studies published as of July 15, 2011, on modern metal-on-metal hip implants. Analyses conducted on outcomes by two joint registries indicate that patients who receive metal-on-metal total hip arthroplasty (THA) and hip resurfacing are at greater risk for revision than are patients who receive THA using a different bearing surface combination. Data from these registries also indicate that larger femoral head components have higher revision rates and risk of revision and that older age is associated with increased revision risks of large-head metal-on-metal THA. Several studies noted a correlation between suboptimal hip implant positioning and higher wear rates, local metal debris release, and consequent local tissue reactions to metal debris. In addition, several studies reported elevated serum metal ion concentrations in patients with metal-on-metal hip articulations, although the clinical significance of these elevated ion concentrations remains unknown.

2017 American College of Rheumatology/American Association of Hip and Knee Surgeons Guideline for the Perioperative Management of Antirheumatic Medication in Patients With Rheumatic Diseases Undergoing Elective Total Hip or Total Knee Arthroplasty

This collaboration between the American College of Rheumatology and the American Association of Hip and Knee Surgeons developed an evidence‐based guideline for the perioperative management of antirheumatic drug therapy for adults with rheumatoid arthritis (RA), spondyloarthritis (SpA) including ankylosing spondylitis and psoriatic arthritis, juvenile idiopathic arthritis (JIA), or systemic lupus erythematosus (SLE) undergoing elective total hip (THA) or total knee arthroplasty (TKA).

Modern metal-on-metal hip resurfacing.

&NA; For this technology overview, the tools of evidence‐based medicine were used to summarize information on the indications, effectiveness, and failure rates of modern metal‐on‐metal hip resurfacing technology. The task was complicated by the fact that resurfacing arthroplasty is commonly offered only to a subset of patients who are candidates for total hip replacement, often prohibiting direct comparisons. Comprehensive literature searches were conducted to address four key questions addressing revision rates, patient characteristics, effectiveness of treatment, and whether improved technique, surgeon experience, and/or patient selection lead to improved outcomes. Despite data limitations, it is apparent that revision rates are higher after resurfacing than after total hip arthroplasty. Potential prognostic indicators did not yield a consistent predictor of patient‐oriented outcomes (eg, pain relief) for either resurfacing arthroplasty or total hip replacement. Because of differences between patients who received hip resurfacing and those who received total hip arthroplasty, the results of studies comparing these techniques cannot be interpreted. Finally, changes in technique and increased experience result in a decrease in revision rates and femoral neck fractures and improved pain and hip scores in resurfacing.

human homotransplantation of left lung: report of a case

Within the past decade, advances in the fundamental research of immunity and improved surgical techniques have resulted in bringing closer the long awaited era of organ transplantation. Indeed, within recent months homotransplantations of lung’ and liver,2 as well as have been attempted in man. The whole field is so rapidly advancing that it is difficult to state fundamental principles, and one cannot help but feel that there are many factors involved in successful transplantations which are, as yet unrecognized. Since Dameshek5 first showed that the immune response could be altered in skin grafts by 6-mercaptopurine, further research has brought forth several promising agents which have proved efficacious in animals as well as in humans in suppressing the immune response. Despite these agents, the variability in our experimental experience in animal lung transplantation makes one feel that the genetic similarity of the donor and host are probably more important for a successful “take” than the means to suppress the immune response. Indeed, pathologists have difficulty in defining rejection, since it is so intimately involved with pathological changes which could be associated with poor surgical techniques, inadequate blood supply, and/ or infection. Probably the weakest link in prolongation of transplant survival today is the lack of a sensitive accurate method to determine imminent host rejection. Basic animal work is, of course, fundamental to the future of organ transplantation, but while this is in progress: efforts should be made in human application in an attempt to bridge the gap between the laboratory and the patient. However, each team must make its own decision as to when it is prepared to approach the clinical application. Our decision was dictated by having an otherwise healthy patient with advanced emphysema, a suitable 2 1-year-old healthy donor dying of a ruptured cerebral aneurysm, an enlightened host family, and a considerable experience in canine lung transplantation prior to clinical application.