Using MRI to Identify ALTR in Asymptomatic Hip Resurfacing Patients
New research from Hospital for Special Surgery demonstrates that magnetic resonance imaging (MRI) is a valuable tool in identifying adverse local tissue reaction (ALTR) in hip arthroplasty patients, even among high-functioning patients with no symptoms and among patients with polyethylene implants.
The results, the authors said, support the use of MRI as part of routine follow-up protocol for hip arthroplasty patients, noting that annual clinical assessment dependent on patients’ self-reported symptoms or blood metal ion testing alone may not detect ALTR.
The study, published online ahead of print by Clinical Orthopaedics and Related Research, is the first to evaluate the presence and risk of ALTR in patients, including asymptomatic patients, who had received implants composed of materials other than metal-on-metal. Previous studies have been limited to metal-on-metal implants.
The researchers prospectively evaluated 206 patients (243 hip arthroplasties) at least 1 year after hip resurfacing arthroplasty or total hip arthroplasty. They examined:
- The volume of joint tissue reaction using MRI images
- Levels of metal particles in the blood
- Patients’ responses on the Hip Disability and Osteoarthritis Outcome Score preoperatively and then annually over the next 3 years
They then compared results for patients who received metal-on-metal hip resurfacing implants with those of patients who underwent total hip arthroplasty with ceramic-on-polyethylene or metal-on-polyethylene implants.
Magnetic resonance imaging identified ALTR in 25% of hip resurfacing patients. This finding was surprising, the researchers said, because these patients had reported symptoms similar to, or less severe than, those of patients with ceramic-on-polyethylene or metal-on-polyethylene implants. Hip resurfacing patients had a significantly larger volume of joint tissue reaction on MRI and a nearly 5 times’ higher risk of having tissue complications than patients with ceramic-on-polyethylene implants. Metal ion levels were inconsistently elevated in patients with these ALTRs.
“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 the study’s senior author, Hollis G. Potter, MD, Chair of the Department of Radiology and Imaging and the Coleman Chair in MRI Research at Hospital for Special Surgery.
“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.”
Lead author Matthew F. Koff, PhD, noted that 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.”
Dr. Potter said that, “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. Widespread use of MRI to assess soft tissue damage may also help identify patterns that could ultimately improve implant design in the future.”
Koff MF, Gao MA, Neri JP, et al. Adverse local tissue reactions are common in asymptomtic individuals after hip resurfacing arthroplasty: interim report from a prospective longitudinal study. Clin Orthop Relat Res. 2021 Jul 7. doi: 10.1097/CORR.0000000000001882. Online ahead of print.