Knee Replacement: Benefits and Risks of Antibiotic-Loaded Bone Cement

MedicalResearch.com Interview with:

Darwin Chen, MD Assistant Professor of Orthopedic SurgeryIcahn School of Medicine at Mount Sinai

Dr. Chen

Darwin Chen, MD
Assistant Professor of Orthopedic Surgery
Icahn School of Medicine at Mount Sinai

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Periprosthetic joint infection unfortunately remains a leading cause of total knee arthroplasty failure. One method of mitigating the risk of PJI is to use antibiotic loaded bone cement in a prophylactic fashion.

While the use of antibiotic cement makes inherent sense, the decision is not as simple as it seems. There are potential side effects such as renal damage, antibiotic hypersensitivity, and antibiotic resistance. Antibiotics decrease the mechanical strength of cement fixation, which may impact component loosening. Additionally, antibiotic cement is significantly more expensive than standard cement, driving up cost. Currently there is no consensus on if antibiotic cement truly reduces infection risk and there are many conflicting studies.

The purpose of our study is the use a large national database to evaluate real world utilization patterns of antibiotic cement, and assess outcomes, complications, and cost associated with antibiotic cement usage. Our hypothesis was that antibiotic cement is associated with a decreased risk of infection and no increased risk of systemic complications. 

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Patient Migration Makes it Difficult To Track Revisions After Total Joint Replacement

MedicalResearch.com Interview with:
Terence J. Gioe, MD
American Joint Replacement Registry, Rosemont, IL
UCSF School of Medicine,
San Francisco VA Health Care System 

MedicalResearch.com: What is the background for this study? What are the main findings? 

Response: Hospital-based or regional registries are typically limited in their catchment area, making loss to follow-up a major concern when patients move out of the area or otherwise receive subsequent medical care outside of the original hospital network. The American Joint Replacement Registry (AJRR), a part of the American Academy of Orthopaedic Surgeons’ (AAOS) registries portfolio, has the goal of tracking total joint arthroplasty (TJA) patients nationally across the US, but currently captures only approximately 28% of annual TJA procedures. Until a nationwide network of reporting hospitals is established that covers at least 90% of all TJA procedures, loss to follow-up due to migration will be a key potential limitation of large-scale studies on implant performance in the US.

Assessment of loss to follow-up can provide an essential understanding of the migration patterns of TJA patients, and help to improve recruitment and enrollment efforts of the AJRR. The magnitude and characteristics of patient migration following TJA have not previously been studied in the US.  Continue reading

Aspirin or Rivaroxaban for VTE Prophylaxis after Hip or Knee Arthroplasty?

MedicalResearch.com Interview with:

Dr. David R. Anderson, MD, FRCPC, FACP Faculty of Medicine Dean, Professor Dean, Faculty of Medicine Division of Hematology, Department of Medicine  & Nova Scotia Health Authority

Dr. Anderson

Dr. David R. Anderson, MD, FRCPC, FACP
Faculty of Medicine Dean, Professor
Dean, Faculty of Medicine
Division of Hematology, Department of Medicine
& Nova Scotia Health Authority

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Blood clots in the lungs (pulmonary embolism) and veins of the legs (deep vein thrombosis) are well recognized complications following total hip and knee arthroplasty surgeries.  Prior to the routine use of antithrombotic prophylaxis, pulmonary embolism was the most common cause of death following these procedures.  Oral anticoagulants such as rivaroxaban are commonly prescribed for the indication of preventing blood clots following total hip or knee arthroplasty.  For maximal benefit these agents are continued following surgery for up to five weeks following total hip arthroplasty and for two weeks following total knee arthroplasty.

There is evidence that aspirin has some benefit for the prevention of deep vein thrombosis and pulmonary embolism following total hip or knee arthroplasty.  However there is less evidence for its benefit than for oral anticoagulants.  We reasoned that aspirin would potentially be an attractive alternative for extended out of hospital prophylaxis following total hip or knee arthroplasty for patients who received a short course (5 days )of rivaroxaban following surgery.  Aspirin would be attractive for this indication because of its low cost, ease of use, and low rates of side effects.

Our study demonstrated that in a randomized controlled trial involving a large group (over 3400) of patients undergoing total hip or knee arthroplasty that extended therapy with aspirin was comparable to rivaroxaban for the prevention of deep vein thrombosis and pulmonary embolism following surgery.  Low rates of complications (< 1%) were observed with both treatment arms.  We also found that rates of clinically important bleeding complications (the most common side effect with antithrombotic drugs) were uncommon and similar with the two agents.

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Patients Who Quit Smoking Had Fewer Adverse Events After Knee Replacement

MedicalResearch.com Interview with:
Amy Wasterlain, MD

Fourth-year orthopaedic surgery resident
NYU Langone Medical Center who led the study with Dr. Richard Iorio 

MedicalResearch.com: What is the background for this study?

Response:  We looked at smoking habits and outcomes for 539 smokers undergoing primary total hip or knee arthroplasty, 73 of whom participated in a pre-operative smoking cessation program. Patients who participated in program were 4.3 times more likely to quit than smokers who tried to quit on their own. Program participants also reduced their tobacco intake dramatically (10.6 fewer cigarettes/day) compared to smokers who didn’t participate (2.3 fewer cigarettes/day), even if they weren’t able to quit completely. Patients who completed the program before undergoing total knee arthroplasty had about 24% fewer adverse events (readmission, venous thromboembolism, stroke, urinary tract infection, pneumonia, and surgical site infection) than smokers who didn’t participate in the program.

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Risk Factors For Adverse Events After Total Shoulder Replacement

MedicalResearch.com Interview with:

Brad Parsons, MD Associate Professor, Orthopaedics Icahn School of Medicine at Mount Sinai

Dr. Parsons

Brad Parsons, MD
Associate Professor, Orthopaedics
Icahn School of Medicine at Mount Sinai

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: As bundled payment initiatives increase in order to contain health care costs, total shoulder arthroplasty (TSA) is a likely future target.

Understanding modifiable drivers of complications and unplanned readmission as well as identifying when such events occur will be critical for orthopedic surgeons and hospitals to improve outcomes and to make fixed-price payment models feasible for TSA.

Utilizing the American College of Surgeons National Surgical Quality Improvement Program we identified 5801 patients that underwent TSA with a 2.7% readmission rate and 2.5% severe adverse event rate. Patients with 3 or more risk factors were found to have a significantly increased risk of readmission and severe adverse events within the first two weeks postoperatively.

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Physical Activity Doesn’t Increase After Hip Replacement

MedicalResearch.com Interview with:
Tom Withers

Research Student, School of Health Sciences
University East Anglia
Norwich, UK

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: There is a lot of subjective evidence to suggest that physical activity does not improve following hip replacement we wanted to therefore synthesise the current evidence to come to a more objective conclusion.

The main finding from this study is that physical activity does not significantly change pre-operatively compared to up to one year post-operatively.

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RATHRR Scale Predicts Readmission After Total Hip Replacement Risk

MedicalResearch.com Interview with:

Chairman and Surgeon-in-Chief Department of Surgery Saint Barnabas Medical Center Professor of Surgery New Jersey Medical School Rutgers University

Dr. Ronald Chamberlain

Ronald S. Chamberlain, MD, MPA, FACS
Chairman and Surgeon-in-Chief
Department of Surgery
Saint Barnabas Medical Center
Professor of Surgery
New Jersey Medical School
Rutgers University

MedicalResearch.com: What is the background for this study?

Dr. Chamberlain:  With the rapidly growing arthritic, aging, and obese population, total hip replacement (THR) has become the most commonly performed orthopedic procedure in the United States (US).  The Affordable Care Act signed by President Barack Obama imposed financial penalties for excess readmissions following certain procedures and diagnoses. While the initial program aimed to reduce readmissions for heart failure, pneumonia, and acute myocardial infarction (AMI), the program expanded to include THR in 2015. With current research estimating a 10%, 30-day readmission rate following a total or partial hip replacement, this study sought to identify factors associated with readmission and to create a scale which could reliably stratify preoperative readmission risk.

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Smoking Increases Complications After Hip or Knee Arthroplasty

Jasvinder Singh MD MPH Professor of Medicine UAB Division of Clinical Immunology and Rheumatology MedicalResearch.com Interview with:
Jasvinder Singh MD MPH
Professor of Medicine
UAB Division of Clinical Immunology and Rheumatology 

Medical Research: What is the background for this study? What are the main findings?

Dr. Singh: A systematic review of the effect of smoking on outcomes after total joint replacement showed that current smoking increased the risk of overall post-operative complications but that there were scarce data for smoking and specific surgical outcomes of arthroplasty. We performed a study using data from an institutional Total Joint Registry to answer this question.   In a study of for 7,926 patients who underwent hip or knee arthroplasty, 7% were current tobacco users. We found that compared to current non-users, current tobacco users had higher hazard ratios (95% CI) for deep infection, 2.37 (1.19, 4.72; p=0.01) and implant revision, 1.78 (1.01, 3.13; p=0.04) after total hip or knee arthroplasty. No significant differences were noted for periprosthetic fractures or superficial infections.

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Knee Replacement Linked To More Pain Relief, Functional Improvement and Adverse Side Effects

Søren Thorgaard Skou PT, PhD Postdoc Research Unit for Musculoskeletal Function and Physiotherapy University of Southern Denmark Clinical Nursing Research Unit Aalborg University Hospital

Søren Thorgaard Skou

MedicalResearch.com Interview with:
Søren Thorgaard Skou PT, PhD Postdoc
Research Unit for Musculoskeletal Function and Physiotherapy
University of Southern Denmark
Clinical Nursing Research Unit
Aalborg University Hospital 

Medical Research: What is the background for this study? What are the main findings?

Response: Total knee replacement has been performed for decades. The number of procedures are increasing and is expected to reach 1 million procedures per year in the US alone in the near future, highlighting the associated future economic burden. However, no studies have compared it to non-surgical alternatives, even though this is important to investigate its effectiveness.

We found that in patients with knee osteoarthritis eligible for total knee replacement, treatment with total knee replacement followed by non-surgical treatment (exercise, education, dietary advice, use of insoles, and pain medication) were associated with greater pain relief and functional improvement after 12 months than the non-surgical treatment alone.

However, both groups had clinically relevant improvements, and patients who underwent total knee replacement had more serious adverse events. Furthermore, most patients who were assigned to receive non-surgical treatment alone did not undergo total knee replacement within the 12 months.

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Chronic Contact Dermatitis May Promote Skin Cancer Development

MedicalResearch.com Interview with:
Shawn Demehri, M.D., Ph.D. Instructor of Medicine Division of Dermatology Washington University in St. Louis andShawn Demehri, M.D., Ph.D.
Instructor of Medicine
Division of Dermatology
Washington University in St. Louis and

 

Wayne M. Yokoyama, M.D. Howard Hughes Medical Institute Rheumatology Division Washington University Medical Center St. Louis, MO 63110-1093Wayne M. Yokoyama, M.D.
Howard Hughes Medical Institute
Rheumatology Division
Washington University Medical Center
St. Louis, MO 63110-1093

MedicalResearch: What are the main findings of the study?

Research: This bedside to bench research has clearly demonstrated a cause and effect relationship between chronic allergic contact dermatitis and skin cancer development. This research originated from a clinical case of invasive skin cancer that developed in the context of chronic allergic contact dermatitis to a nickel-containing metal implant. Using animal models, we have demonstrated that chronic exposure to a contact allergen creates an inflammation that drive skin cancer development.
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Hormone Replacement Therapy Found Protective of Hip, Knee Joint Replacements

Professor Nigel Arden Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences Botnar Research Centre Windmill Road Oxford  OX3 7LDMedicalResearch.com Interview with:
Professor Nigel Arden
Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences
Botnar Research Centre
Oxford  OX3 7LD

MedicalResearch.com: What are the main findings of the study?

Professor Arden: We found that in a cohort of women who had used hormone replacement therapy (HRT) and underwent knee or hip replacement their risk of implant revision was reduced by about 40% compared to non-users of HRT.
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