Dinko Nizić1, Marko Šimunović2, Goran Pavliša2, Mislav Jelić3. 1. Department of Radiology and Ultrasound Diagnostics, Special Hospital for Pulmonary Diseases, Rockefellerova 3, 10000, Zagreb, Croatia. dinko.nizic@gmail.com. 2. Clinical Institute of Diagnostic and Interventional Radiology, University Hospital Center Zagreb, University of Zagreb, Kišpatićeva 12, 10000, Zagreb, Croatia. 3. Department of Orthopaedic Surgery, University Hospital Center Zagreb, School of Medicine, University of Zagreb, Šalata 6-7, 10000, Zagreb, Croatia.
Abstract
PURPOSE: The purpose of this retrospective cross-sectional case-control study was to evaluate an alternative imaging test for lateralization of the tibial tuberosity, unbiased towards knee rotation. METHODS: On axial CT images of 129 knees, classified as cases (two or more patellar luxations) and controls (no patellar luxations), two raters gauged the standard tibial tuberosity-trochlear groove (TT-TG) distance, tibial tuberosity-femoral intercondylar midpoint (TT-FIM) distance, and new tibial tuberosity-tibial intercondylar midpoint (TT-TIM) distance singly, and knee longitudinal rotation angles (LRAs), and the presence of femoral trochlear dysplasia (FTD) jointly. RESULTS: All imaging tests intercorrelated and discriminated between stability groups. TT-TIM had the lowest values with the highest precision. Though poorly, TT-TG and TT-FIM negatively correlated with age and LRAs regarding femur, but positively with presence of FTD, whereas TT-TIM was unbiased. The accuracy of TT-TG (> 20 mm), TT-FIM (> 20 mm), and TT-TIM (> 13 mm) was good with almost perfect reproducibility. Only TT-TIM was sex-biased (p = 0.009), with > 12 mm cut-off in females and (presumably) > 14 mm in males. CONCLUSION: TT-TIM is an alternative imaging test for lateralization of the tibial tuberosity, unbiased towards knee rotation.
PURPOSE: The purpose of this retrospective cross-sectional case-control study was to evaluate an alternative imaging test for lateralization of the tibial tuberosity, unbiased towards knee rotation. METHODS: On axial CT images of 129 knees, classified as cases (two or more patellar luxations) and controls (no patellar luxations), two raters gauged the standard tibial tuberosity-trochlear groove (TT-TG) distance, tibial tuberosity-femoral intercondylar midpoint (TT-FIM) distance, and new tibial tuberosity-tibial intercondylar midpoint (TT-TIM) distance singly, and knee longitudinal rotation angles (LRAs), and the presence of femoral trochlear dysplasia (FTD) jointly. RESULTS: All imaging tests intercorrelated and discriminated between stability groups. TT-TIM had the lowest values with the highest precision. Though poorly, TT-TG and TT-FIM negatively correlated with age and LRAs regarding femur, but positively with presence of FTD, whereas TT-TIM was unbiased. The accuracy of TT-TG (> 20 mm), TT-FIM (> 20 mm), and TT-TIM (> 13 mm) was good with almost perfect reproducibility. Only TT-TIM was sex-biased (p = 0.009), with > 12 mm cut-off in females and (presumably) > 14 mm in males. CONCLUSION:TT-TIM is an alternative imaging test for lateralization of the tibial tuberosity, unbiased towards knee rotation.