动态髌股关节轴位摄片对髌骨轨迹异常的评价

THE EVALUATION OF PATELLAR TRACKING ABNORMALITIES BY DYNAMIC AXIAL PATELLOFEMORAL JOINT RADIOGRAPHY

目的 通过动态髌股关节轴位摄片适合角（CA）的测量，对屈膝过程中髌骨轨迹进行研究，探讨髌骨轨迹异常的诊断及其分类。方法 选择15例（30膝）无与髌股关节有关症状或体征的志愿者作为对照组（A组），将43例（68膝）有膝前痛，临床检查诊断为髌骨排列异常病人分为3组：B组（外侧不稳组）19例病人（33膝），手推髌骨髌骨外侧移动增加，FAIRBANK征阳性；C组（内侧不稳组）8例病人（14膝），内推髌骨时其内移增加，同时诱发疼痛和恐惧，FAIRBANK征阴性，外推髌骨不会增加其外侧移动；D组（多项不稳组）16例病人（21膝），查体时会增加髌骨向内、外方向的移动，同时会诱发恐惧和疼痛，对每一病膝及正常对照膝拍摄屈膝15°、30°、45°、60°、90°髌股关节轴位X线片进行CA测量并对照分析，根据CA测量结果将D组中屈膝15°CA值小于-10°病人定为D1组（内→外不稳组），CA值大于＋16°的病人定为D2组（外→内不稳组）。结果 A组屈膝各角度CA平均值均正常；B组屈膝各角度CA值均大于正常值，且屈膝15°～90°CA值有缩小趋势；C组屈膝各角度CA值均小于正常值，且屈膝15°～90°CA值由小到大；D1组和D2组CA值屈膝15°～90°变化最明显，其曲线完全相反。结论 动态髌股关节轴位摄片能对髌骨轨迹异常进行评价。

Objective To study the diagnosis and classification of abnormal patella tracking through dynamic axial patellofemoral X-ray image during knee flexing and measuring its congruence angle （CA）. Methods This study was divided into the following four groups. Group A （control group） ： 15 volunteers （30 knees） without any knee symptoms or signs; Group B： 19 patients （33 knees） with lateral instability, with increased lateral excursion of the patella while being pushed, and positive FAIRBANK sign; Group C：eight patients （14 knees） with medial instability, with increased medial excursion of the patella and induced pain and fear while being pushed medially, but none demonstrated increased lateral patellar excursion while pushed laterally, FAIRBANK sign being negative; Group D： 16 patients （21 knees） with multi-directional instability, with increased excursion of the patella in both medial and lateral directions while being pushed medially and laterally, and pain and fear were induced as well. Dynamic axial radiographies of patella femoral joints with modified X-ray technique were made with knees flexing at 15, 30, 45, 60, and 90 degrees, and CA were measured and analyzed. Group D was further divided into two sub-groups according to CA measurement at knee flexing angle of 15 degrees. Those with CA〈10 degrees were classified as Group D1 （medial→lateral instability）; those with CA〉16 as group D2 （lateral→medial instability）. Results In group A, the average values of CA at each knee flexing angle were within normal range： those in group B were greater than normal values at all tested knee flexing angles, and there was a tend ency to decrease the CA values with the increase of knee flexing angles; those in group C were lower than normal at all tested knee flexing angles. There was a tendency of the CA values along with the increase of knee flexing angles. The CA values were mostly changed in groups D1 and D2, but the curves in these two groups were reversed completely. Conclusion The dynamic axial patellofemoral joint imaging can be used to evaluate the patellar tracking abnormalities.