NEW YORK, July 8, 2021 /PRNewswire/ — Magnetic resonance imaging (MRI) identified adverse local tissue reactions in patients who received hip replacements, even among those who were high-functioning and had no symptoms, according to a new study by researchers at Hospital for Special Surgery (HSS). The results suggest MRI is uniquely capable of assessing soft-tissue complications and that the use of MRI should be included as part of routine follow-up protocol for hip replacement patients, as an annual clinical assessment dependent on survey or blood metal ion testing alone may not detect complications.
The study, published yesterday in Clinical Orthopaedics and Related Research, is the first to evaluate the presence and risk of local tissue complications after hip replacements made of different materials in patients, including those who are asymptomatic. Previous studies have been limited to metal-on-metal implants.
Hip replacement parts are made of plastic, ceramic, metal or a combination of these materials. The components move against each other and wear down slowly through regular use. Small wear particles can break free from the hip replacement material over time and damage local joint tissues. MRI is a non-invasive imaging technique that uses a large magnet and radiofrequency energy to produce digital images without the use of ionizing radiation. MRI is often used in orthopedics to visualize the soft tissues around total hip replacements that are affected by the small wear particles. 
“We found that patients can be completely asymptomatic and have high-functioning hip scores while harboring reactions that could start to destroy the soft tissues around the hip,” said Hollis G. Potter, MD, chairman of the Department of Radiology and Imaging and the Coleman Chair in MRI Research at HSS and the study’s senior author. “This finding is important because tissue reactions typically worsen over time. Delayed detection results in unnecessary pain, longer and more complicated revision operations and more challenging recoveries.”
Matthew F. Koff PhD, the lead study author said, “The study also indicates that MRI is clinically useful for patients who receive a ceramic-on-polyethylene or metal-on-polyethylene implant, in addition to patients who received a hip resurfacing arthroplasty.”
Drs. Potter and Koff and HSS colleagues prospectively evaluated 206 patients (243 hip replacements) at least one year after having hip resurfacing arthroplasty or total hip replacement. The researchers examined the volume of joint tissue reaction using MRI images, levels of metal particles in the blood and patients’ responses on a survey called the Hip Disability and Osteoarthritis Outcome Score annually over the course of 3 years. The researchers compared results for patients who received hip resurfacing arthroplasty (HRA) with patients who received ceramic-on-polyethylene and metal-on-polyethylene total hip replacements.
During the study, MRI identified adverse local tissue reactions in 25 percent of patients who had hip resurfacing arthroplasty. This finding was surprising, since these patients reported symptoms similar to or less severe than patients with ceramic-on-polyethylene and metal-on-polyethylene total hip replacements implants. Patients who received hip resurfacing arthroplasty had a significantly larger volume of joint tissue reaction on MRI, a nearly five-times-higher risk of having tissue complications than patients who had a ceramic-on-polyethylene total hip replacement. Metal ion levels were inconsistently elevated in the patients with these reactions.
“By sharing our findings, we hope physicians will start incorporating MRIs into patient assessments, leading to earlier detection of issues and better outcomes for patients,” Dr. Potter said. “Widespread use of MRI to assess soft tissue damage may also help identify patterns that could ultimately improve implant design in the future.”
About HSS
HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the 11th consecutive year), No. 4 in rheumatology by U.S. News & World Report (2020-2021), and the best pediatric orthopedic hospital in NY, NJ and CT by U.S. News & World Report “Best Children’s Hospitals” list (2021-2022). HSS is ranked world #1 in orthopedics by Newsweek (2020-2021). Founded in 1863, the Hospital has the lowest complication and readmission rates in the nation for orthopedics, and among the lowest infection rates. HSS was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center five consecutive times. The global standard total knee replacement was developed at HSS in 1969. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State, as well as in Florida. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. The HSS Global Innovation Institute was formed in 2016 to realize the potential of new drugs, therapeutics and devices. The HSS Education Institute is a trusted leader in advancing musculoskeletal knowledge and research for physicians, nurses, allied health professionals, academic trainees, and consumers in more than 130 countries. The institution is collaborating with medical centers and other organizations to advance the quality and value of musculoskeletal care and to make world-class HSS care more widely accessible nationally and internationally. www.hss.edu.
SOURCE Hospital for Special Surgery
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