Evaluating a semiquantitative magnetic resonance imaging-based scoring system to predict hip preservation or arthroplasty in patients with an intact preoperative joint space.

Abstract

Subjective interpretation of magnetic resonance imaging (MRI) findings in the setting of early hip osteoarthritis can be challenging with little agreement between surgeons. While arthroplasty is rarely indicated for patients with preserved joint space, it may be the preferred surgical option when advanced imaging reveals severe intra-articular pathology. The purpose of this study was to evaluate a semiquantitative MRI-based scoring system in patients undergoing surgery for hip pain without advanced radiographic joint space loss. Consecutive patients with hip pain refractory to conservative measures and without severe radiographic hip osteoarthritis [Tönnis grade 0-1, Joint Space Width (JSW)> 3 mm] who received primary total hip arthroplasty with a preoperative MRI were included. This cohort was propensity-matched by Tönnis grade and JSW, as well as age, gender, and BMI, to patients undergoing hip preservation surgery. Preoperative MRIs were evaluated according to the Scoring Hip Osteoarthritis with MRI (SHOMRI) grading system. SHOMRI scores were compared between the arthroplasty and hip preservation cohorts with threshold values calculated to evaluate associations with treatment pathways. Patients undergoing arthroplasty had significantly greater SHOMRI total scores as well as cartilage component scores. Threshold values for the cartilage component SHOMRI score were significantly associated with the designated surgical treatments between the two groups (<i>P</i> < .001). Subjects in each treatment group had significant postoperative improvement to the 2-year time point with high postoperative satisfaction, indicating appropriate treatment designation. Application of SHOMRI scoring thresholds may decrease subjectivity in surgeon decision making when using advanced imaging in patients without significant radiographic osteoarthritis.