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OBJECTIVE. The purpose of this study is to describe postoperative MRI findings after femoroacetabular impingement surgery in correlation with pain changes and surgical findings. SUBJECTS AND METHODS. We prospectively enrolled 42 patients (43 hips) who were scheduled for FAI surgery. Pre- and postoperative MR images were obtained using a 3-T MRI system. Changes in pain scores were assessed using the hip dysfunction and osteoarthritis outcome score. MR images were evaluated for the presence of acetabuloplasty or femoroplasty, presence of chondral and labral repair surgery, bone marrow edema, subchondral cysts, chondral defects, labral tears, capsular defects, and effusion. The optimal orientation to detect these changes was noted. Imaging findings were compared with pain score changes using linear regression analysis. Sensitivity and specificity were assessed using surgical correlation as the reference standard. RESULTS. Increased acetabular bony débridement length was associated with decreased improvement in pain scores (coefficient, -2.07; 95% CI, -3.53 to -0.62; p = 0.008), whereas other imaging findings were not significantly different. Femoroplasty and capsular alterations were best detected on oblique axial sequences; acetabuloplasty and cartilage and labral repair were best seen on sagittal sequences. MRI showed excellent sensitivity (100%) and specificity (100%) for detecting labral repair and excellent sensitivity for detecting femoroplasty (98%). Sensitivity and specificity were lower for detecting acetabuloplasty (83% and 80%, respectively) and chondral repair (75% and 54%, respectively). CONCLUSION. Arthroscopic acetabuloplasty showed a greater association with postoperative pain than did other aspects of surgical correction for femoroacetabular impingement. Femoroplasty and labral repair were reliably diagnosed on 3-T MRI; however, limitations were found in the evaluation of acetabular chondral repair.

ObjectiveTo determine if presence of calcium-containing crystals (CaC) is associated with increased knee joint degeneration over 4 years and assess if total number of CaCs deposited is a useful measure of disease burden.DesignSeventy subjects with CaCs in right knees at baseline were selected from the Osteoarthritis Initiative and matched to 70 subjects without evidence of CaCs. T1-weighted gradient-echo sequences were used to confirm presence of CaCs and count the numbers of distinct circumscribed CaCs. Morphological abnormalities were assessed at baseline and 4-year follow-up using the modified semi-quantitative Whole-Organ Magnetic Resonance Imaging Score (WORMS). Linear regression models were used to analyze the associations between presence of CaCs at baseline and changes in WORMS and to analyze the associations between numbers of circumscribed CaCs at baseline and changes in WORMS.ResultsPresence of CaCs was associated with increased cartilage degeneration in the patella (coefficient: 0.33; 95% confidence interval (CI): 0.04-0.63), the medial femur (coefficient: 0.51; 95% CI: 0.18-0.83), the lateral tibia (coefficient: 0.36; 95% CI: 0.01-0.71) as well as the medial and lateral meniscus (coefficient: 0.38; 95% CI: 0.00-0.75 and coefficient: 0.72; 95% CI: 0.12-1.32). Knees with higher numbers of CaCs had increased cartilage degeneration in the patella and medial femur (coefficient: 0.09; 95% CI: 0.05-0.14; P