3-Tesla Magnetic Resonance Imaging as an Additional Radiographic Decision Aid for Oxford Unicompartmental Knee Arthroplasty Patient Selection

Abstract

Background: The indications for Oxford unicompartmental knee arthroplasty (UKA) have been investigated for decades. The use of radiological decision aids for Oxford UKA is widespread; however, recent evidence suggests that there is a high false-negative rate. The 3-Tesla (3T) magnetic resonance imaging (MRI) system is more accurate than the 1.5T MRI system and may perform even better with Stage III and IV osteoarthritis. Here, we investigated the relationship between MRI findings and patient-reported outcomes following Oxford UKA. Methods: Medical records were reviewed retrospectively for 94 patients (101 knees) receiving Oxford UKA. All patients had a preoperative 3T MRI scan, which identified full-thickness cartilage loss. Evidence of bone-on-bone lesions from plain X-ray, bone marrow edema, and medial meniscus root tear was also recorded. Clinical outcomes were assessed using the Oxford knee score (OKS), Tegner Lysholm knee scoring system (TLKSS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) six months postoperatively. Results: We reviewed 94 patients (101 knees, 30 in male patients and 71 in female patients) with full-thickness cartilage loss on 3T MRI. There were no significant differences in the TLKSS, OKS, or WOMAC between groups with and without bone-on-bone lesions, bone marrow edema, or medial meniscus root tear six months postsurgery. Conclusion: The 3T MRI system is an applicable radiographical decision aid for Oxford UKA patient selection. Full-thickness cartilage loss on 3T MRI is sufficient for identifying Oxford UKA beneficiaries, regardless of bone-on-bone lesions, bone marrow edema, or medial meniscus root tear