2022, Vol. 26 ›› Issue (36): 5781-5786

A new evaluation index for patellofemoral instability: tibial nodule torsion angle

Li Weixiang, Xu Bin, Jiang Shaowei   

Abstract: BACKGROUND: Patellar dislocation is more common in young female patients, and it is a common cause of adolescent knee pain. For the treatment of patellar dislocation, clinical treatment is divided into surgical treatment and conservative treatment. Surgical treatment generally chooses the medial patellofemoral ligament revascularization. Postoperative recurrence of dislocation may be due to failure to correct risk factors, which requires combined osteotomy and orthopedic treatment. In this way, the anatomical structure of the bone can be changed and the skeletal deformity can be corrected. However, it is still controversial in clinic whether patients need to undergo tibial nodule osteotomy and orthopedic surgery before surgery.
OBJECTIVE: A new evaluation index affecting the stability of patellofemoral joint is introduced. Tibial nodule torsion angle: The correlation between tibial nodule torsion angle and patellar dislocation was measured and analyzed. The diagnostic and clinical practical values of tibial nodule torsion angle for patellar dislocation were studied, and the correlation of tibial nodule torsion angle with tibial tubercle-trochlear groove distance and patellar inclination angle was evaluated.   
METHODS: A total of 42 patients with bone dislocation were collected from the Department of Sports Trauma and Arthroscopic Surgery of First Affiliated Hospital of Anhui Medical University from January to August 2020, and 46 patients with cruciate ligament injury or meniscus injury were considered as the control group. Tibial nodule torsion angle, tibial tubercle-trochlear groove distance and patellar inclination angle of the two groups were measured under CT. The three parameters of the data of the two groups were statistically analyzed. The correlation between tibial nodule torsion angle and patellar dislocation was analyzed and the clinical application value of tibial nodule torsion angle was evaluated.   
RESULTS AND CONCLUSION: (1) Tibial nodule torsion angle was statistically different between the two groups (P < 0.05). (2) Compared with the other two parameters, tibial nodule torsion angle could be used as a risk factor for patellar dislocation, and had a certain diagnostic ability for patellar dislocation (area under curve=0.923). (3) It is indicated that tibial tubercle torsion angle is closely related to patellar dislocation, and has a certain diagnostic ability for patellar dislocation. Tibial tubercle torsion angle compared with the other two parameters can be incorporated into the factors affecting the stability of patellofemoral joint and can be used in preoperative evaluation to provide a reference for the selection of surgical procedure for patellar dislocation.
Key words: patellar dislocation, patellofemoral joint stability, tibial tuberosity torsion, tibial tubercle-trochlear groove distance, patellar inclination angle, tibial tuberosity osteotomy