Wang Daofeng, Liu Yang, Sun Jianzhong, Fu Qizhen, Lv Chengcheng, Yue Tian, Tang Zhengjie, Zhang Zhijun, Zhang Hui
Sports Medicine Service, Beijing Jishuitan Hospital, Capital Medical University, Beijing, China.
Beijing Research Institute of Traumatology and Orthopaedics, Beijing, China.
Knee Surg Sports Traumatol Arthrosc. 2025 Jul;33(7):2379-2389. doi: 10.1002/ksa.12584. Epub 2025 Jan 13.
To propose a new sign of patellar maltracking in recurrent patellar dislocation (RPD) and compare the differences in lower limb rotational and bony structural abnormalities among the different signs.
A retrospective study included 279 patients (mean age: 22 years; female: 81%) who underwent primary surgery for RPD over the past 4 years was performed. The patients were grouped based on the characteristics of patellar tracking: low-, moderate- and high-grade J-sign. Patients were further divided into 'jumping' and 'gliding' subgroups based on whether the patella exhibited a 'jumping' sign during flexion-extension motion. All patients received bilateral standard hip-knee-ankle CT scans. The rotational and bony structural parameters of affected knees were measured, and the differences in these variables among the groups were described and analyzed. Reliability analysis was performed to test the consistency of J-sign grading and measurements.
There were 92, 100 and 87 patients in the low-, moderate- and high-grade J-sign, respectively. The overall incidence of the jumping sign is 37%. The incidence of the 'Jumping sign' in the high-grade J-sign was significantly higher than in the other two groups (82% vs. 32% vs. 0, p < 0.001). Compared to those with the gliding sign, patients with the jumping sign have higher proportions of increased femoral anteversion (40.8% vs. 24.4%, p = 0.004), excessive knee torsion (61.2% vs. 15.3%, p < 0.001), trochlear dysplasia (95.1% vs. 69.3%, p < 0.001), pronounced supratrochlear spur (73.1% vs. 32.3%, p < 0.001), increased tibial tuberosity-trochlear groove distance (68% vs. 43.3%, p < 0.001), flatter lateral trochlear inclination (81.3% vs. 27.5%, p < 0.001) and excessive sulcus angle (68.7% vs. 35.3%, p = 0.003). No significant morphological differences were found in various bony structural parameters between knees with jumping sign and high-grade J-sign (all p > 0.05). The inter-observer reliability kappa values were 0.65 for the quadrant classification and 0.83 for the new patellar sign.
In RPD patients, the rotational and bony structural abnormalities in the jumping sign are highly consistent with the high-grade J sign. This finding may assist the surgeon and their patients in making informed decisions about further imaging tests and osteotomy procedures in the treatment of RPD.
Level IV, cross-sectional study.
提出复发性髌骨脱位（RPD）中髌骨轨迹不良的一种新体征，并比较不同体征在下肢旋转和骨骼结构异常方面的差异。
进行了一项回顾性研究，纳入了过去4年中因RPD接受初次手术的279例患者（平均年龄：22岁；女性：81%）。根据髌骨轨迹特征将患者分为低、中、高等级J征组。根据髌骨在屈伸运动中是否表现出“跳跃”征，患者进一步分为“跳跃”和“滑动”亚组。所有患者均接受双侧标准髋-膝-踝CT扫描。测量患侧膝关节的旋转和骨骼结构参数，并描述和分析各组间这些变量的差异。进行可靠性分析以检验J征分级和测量的一致性。
低、中、高等级J征组分别有92例、100例和87例患者。跳跃征的总体发生率为37%。高等级J征组中“跳跃征”的发生率显著高于其他两组（82%对32%对0，p<0.001）。与有滑动征的患者相比，有跳跃征的患者股骨前倾增加（40.8%对24.4%，p = 0.004）、膝关节过度扭转（61.2%对15.3%，p<0.001）、滑车发育不良（95.1%对69.3%，p<0.001）、明显的滑车嵴（73.1%对32.3%，p<0.001）、胫骨结节-滑车沟距离增加（68%对43.3%，p<0.001）、外侧滑车倾斜度更平（81.3%对27.5%，p<0.001）和沟角过大（68.7%对35.3%，p = 0.003）的比例更高。有跳跃征的膝关节与高等级J征膝关节在各种骨骼结构参数上未发现显著形态学差异（所有p>0.05）。观察者间可靠性kappa值，象限分类为0.65，新髌骨征为0.83。
在RPD患者中，跳跃征的旋转和骨骼结构异常与高等级J征高度一致。这一发现可能有助于外科医生及其患者在RPD治疗中就进一步的影像学检查和截骨手术做出明智决策。
IV级，横断面研究。
