Intercondylar Notch Width as a Risk Factor for Medial Femoral Condyle Osteochondritis Dissecans in Skeletally Immature XXXX .

@entity1 @entity1843 @entity158 @entity5818 @entity2096
BACKGROUND: @entity1843 ( @entity1843 ) of the medial femoral condyle (MFC) is one of the most common causes of knee @entity158 in adolescents. Wilson sign reproduces knee @entity158 with internal rotation of the tibia during extension of the knee from 90 to 30 degrees due to impingement of the tibial eminence on the MFC. This impingement may result in microtrauma and contribute to lesion formation. The purpose of this study was to evaluate anatomic factors that may increase the likelihood of impingement by using magnetic resonance imaging scans of @entity1 with @entity2096 to measure tibial eminence height and femoral notch width. METHODS: A retrospective, case-control study was performed using the radiology database at our institution between July 2009 and February 2014. Magnetic resonance imagings of @entity1 with @entity2096 and matched controls were identified. For each @entity1 , tibial eminence height and femoral notch width were measured and then normalized for @entity1 size [creating the tibial eminence height normalized, and the notch width index (NWI), respectively]. Values for @entity1843 and control knees were compared using Student t test. Interrater and intrarater reliability were calculated using intraclass correlation coefficients. RESULTS: Thirty-five MFC @entity1843 @entity1 and matched controls were identified. Comparison of the groups showed a significantly smaller NWI in MFC @entity1843 knees than in the matched controls (0.2620  0.0248 vs. 0.2886   0.0323, P=0.0003). There was no difference in tibial eminence height normalized between groups (0.1387  0.0161 vs. 0.1428  0.0108, P=0.21). Interrater and intrarater reliability of all measurements was good to excellent (0.81 to 1.00) when measurements were made using bony margins. CONCLUSIONS: Knees with @entity2096 have significantly smaller NWIs than matched controls. This anatomic factor may increase the likelihood of @entity5818 and contribute to @entity1843 formation. LEVEL OF EVIDENCE: Level III-case-control study.
