To explore the changes in ankle mortise morphology and the influencing factors of ankle joint function after open reduction and internal fixation surgery for ankle joint fractures.

The patients with ankle fractures and accepted open reduction and internal fixation in the orthopedics d epartment of Nantong Hospital Affiliated to Shanghai University from January 2018 to June 2021 were selected and divided into the excellent group, the good group, and the fair to poor group based on the American Foot and Ankle Association ankle and posterior foot function score (AOFAS). Multiple factor linear regression analysis was used to analyse the relationship between AOFAS score and morphological indices of ankle joint( including the width, depth, coronal and sagittal angles).

A total of 98 patients were enrolled. Changes in ankle morphology: (1) compared with the healthy side, the width, depth, and coronal and sagittal angles of the ankle on the affected side of patients with ankle fracture after open reduction and internal fixation were significantly increased(t=6.835, 3.523, 6.105, 10.670, all P<0.05). (2)AOFAS score of ankle joint function in patients with ankle fracture after open reduction and internal fixation surgery was (77±9). The differences in ankle shape indices between the healthy and sick sides of the three groups were statistically significant (F=396.749, 136.520, 59.694, 406.548, all P< 0.05). (3) The difference in morphological indices of ankle joint between the healthy and sick sides of postoperative patients was significantly negatively correlated with the AOFAS score of ankle joint function (r=-0.368, -0.398, -0.208, -0.423, all P< 0.05). Factors influencing ankle joint function: (1) comparison of AOFAS for different ages, start of rehabilitation, and adherence to functional training showed statistically significant differences (t=2.460, 3.549, both P<0.05). (2) Age[B=0.386, 95%CI(0.207, 0.565), P<0.001], adherence to functional training[B=-9.623, 95%CI(-15.118, -4.129), P=0.001], and the differences in ankle width between the affected and healthy sides [B=-1.200, 95%CI(-1.785, -0.614), P<0.001] were the main influencing factors on postoperative AOFAS scores of ankle joint function.

There is a significant negative correlation between the changes in ankle morphology and ankle joint function in patients after open reduction and internal fixation for ankle joint fractures.