Predictors of Adverse Local Tissue Reaction in a High-Risk Population.

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Medical Diagnostics

Background:

• Adverse local tissue reaction (ALTR) is a known complication of metal-on-polyethylene (MoP) total hip arthroplasty (THA).
• Certain MoP THA implant models show a higher incidence of ALTR.
• Predictive factors for ALTR in high-risk THA patients require further investigation.

Purpose of the Study:

• To identify if serum metal levels, patient symptoms, implant characteristics, and imaging findings can predict ALTR in a high-risk MoP THA population.
• To analyze the association between specific implant factors and ALTR development.
• To evaluate the utility of various clinical and radiographic parameters in diagnosing ALTR.

Main Methods:

• Retrospective review of 474 patients undergoing MoP THA with increased ALTR risk.
• Stratification of patients based on the presence or absence of ALTR.
• Comparison of patient symptoms, serum cobalt and chromium levels, femoral head offset, and imaging findings (MARS MRI).

Main Results:

• ALTR patients were significantly more symptomatic (52.9% vs 9.9%) and had higher serum cobalt and chromium levels.
• Larger femoral head offsets (>4 mm) were associated with a higher prevalence of ALTR (53% vs 38%).
• ALTR was linked to larger joint effusions (4.7 cm vs 2.1 cm) and increased trochanteric bursitis on MARS MRI.

Conclusions:

• Elevated serum cobalt and chromium levels are present in high-risk MoP THA, even without ALTR.
• Increased femoral head offset is a significant risk factor for ALTR development.
• Risk stratification for painful THA with elevated metal ions should incorporate patient symptoms, imaging, and implant factors.