Objective To localize the tibial attachment of the posterior cruciate ligament (PCL) on the magnetic resonance imaging (MRI) and provide parameters for clinical PCL reconstruction.Methods We retrospectively analyzed 524 patients with intact tibial PCL attachment who had undergone knee MRI from January 2010 to January 2016.They were 286 men and 238 women with an average age of 35 years (from 20 to 50 years).The size and positions of the tibial PCL attachment were measured on the sagittal and coronal MRI slices.The differences were analyzed between different genders.Results On the sagittal slices,the mean distance from the central tibial PCL attachment to the posterior edge of the tibial plateau was 17.9 ± 3.0 mm and the mean anteroposterior diameter of the tibial PCL attachment was 9.7 ± 2.4 mm,with those for males significantly larger than for females (P ＜ 0.05).The above mean values when expressed as a percentage of the posterior tibial slop were 79.9％ ±4.5％ and 43.7％ ± 9.6％,respectively,showing no significant differences between males and females (P ＞ 0.05).On the coronal slices,the distances from the central tibial PCL attachment to the medial and lateral edges of the tibial plateau were 33.5 ± 3.1 mm and 37.4 ±4.1 mm,respectively,and the mediolateral diameter of the tibial PCL attachment was 12.0 ± 1.6 mm,with those for males significantly larger than for females (P ＜ 0.05).The above mean values when expressed as a percentage of the mediolateral diameter of the tibial PCL attachment were 47.4％ ± 3.2％,52.7％ ±3.1％ and 16.9％ ± 1.7％,respectively,showing no significant differences between males and females (P ＞ 0.05).Conclusions On knee MRI images,the distance from the central tibial PCL attachment to the posterior edge of the tibial plateau is about 17.9 mm,the anteroposterior diameter of the tibial PCL attachment around 9.7 mm,and the mediolateral diameter of the tibial PCL attachment roughly 12.0 mm.These measurements for males are larger than for females.

Objective:To measure the anatomical parameters of the simulated low tibial tunnel of posterior cruciate ligament (PCL) based on knee CT images so as to provide clinical reference for accurate location of the tunnel.Methods:The CT images of 201 healthy knee joints collected at Department of Orthopedics, The Second Hospital of Lanzhou University from June 2016 to September 2021 were used for simulation of the PCL low tibial tunnel. The anatomical parameters of the tibial tunnel were measured using the RadiAnt DICOM Viewer. The primary measures included the angle between tibial plateau and tibial tunnel (ATPT) and the perpendicular distances from the tibial tunnel entrance and exit point to the tibial plateau (L1 and L2). The secondary measures included the angle between tibial plateau and posterior slope (PSA), the angle between tibial anatomical axis and central line of tibial tunnel (ATAA), the angle between posterior tibial slope line and the central line of tibial tunnel (APST), the anterior and posterior diameter of tibial plateau (APD), the length of posterior tibial slope (LPTS), and the length of tibial tunnel (LTT). The measurement results were analyzed according to the body height (divided into 3 groups: a 1.00 to 1.60 m group, a 1.61 to 1.70 m group, and a ≥1.71 m group) and gender using the software IBM SPSS 26.Results:The primary measures: ATPT was 37.0°±4.5°, and L1 and L2 were respectively (57.8±7.4) mm and (34.5±3.3) mm. The secondary measures: PSA 128.1°±5.4°, ATAA 52.7°±4.1°, APST 89.1°±5.9°, APD was (32.9±2.6) mm, LPTS (20.5±2.4) mm, and LTT (40.9±5.7) mm. After grouping by gender, there was no significant difference in PSA between men and women ( P>0.05) while there were significant differences in the other indexes between men and women ( P<0.05). After grouping by body height, there was no significant difference in ATPT, PSA, APST or ATAA between the 3 groups (1.00 to 1.60 m group, 1.61 to 1.70 m group and ≥1.71 m group) ( P>0.05) while there were significant differences in L1, L2, APD, LPTS and LTT between the 3 groups ( P<0.05). Conclusions:Based on the knee CT images, the primary measures of PCL low tibial tunnel are as follows: the angle between tibial plateau and tibial tunnel is 37.0°±4.5°, and the perpendicular distances from the tibial tunnel entrance and exit point to the tibial plateau are (57.8±7.4) mm and (34.5±3.3) mm, respectively. Gender and body height are the important factors influencing the above measurement outcomes.

Objective:To compare the efficacy of medial patellofemoral ligament (MPFL) reconstruction using single half tunnel, double half curved tunnel and suture anchor fixation in the treatment of patellar dislocation.Methods:A retrospective cohort study was used to analyze the clinical data of 58 patients with patellar dislocation treated in Second Hospital of Lanzhou University from June 2018 to February 2021, including 22 males and 36 females, aged 12-34 years [(19.6±5.5)years]. MPFL reconstruction was performed arthroscopically using single half tunnel fixation in 20 patients (single half tunnel group), double half curved tunnel fixation in 18 (double half curved tunnel group) and suture anchor fixation in 20 (suture anchor group). The Lysholm score, International Knee Documentation Committee (IKDC) score and Tegner activity score were compared among groups before operation, at 3 months after operation and at the last follow-up. The knee range of motion was compared among the three groups at 3 months after operation and at the last follow-up. The postoperative complications of the three groups were observed at the last follow-up.Results:All patients were followed up for 9-39 months [(26.5±9.1)months]. In single half tunnel group, double half curved tunnel group and suture anchor group, the Lysholm score was (78.4±12.0)points, (88.7±7.5)points and (81.1±9.8)points at 3 months after operation, and (80.4±14.2)points, (90.9±9.0)points and (83.3±9.1)points at the last follow-up. The postoperative Lysholm score in all groups was significantly increased from that preoperatively (all P<0.01). The Lysholm score in double half curved tunnel group was significantly higher than that in other two groups at 3 months after operation and at last follow-up (all P<0.05), but there was no significant difference between other groups (all P>0.05). In single half tunnel group, double half curved tunnel group and suture anchor group, the IKDC score was (76.7±12.2)points, (78.4±8.9)points and (81.0±8.1)points at 3 months after operation, and (77.6±15.8)points, (83.2±7.8)points and (82.4±12.4)points at the last follow-up. The postoperative IKDC score in all groups was significantly increased from that preoperatively (all P<0.01), but there was no significant difference among the three groups (all P>0.05). In single half tunnel group, double half curved tunnel group and suture anchor group, the Tegner score was (4.0±1.2)points, (5.4±1.7)points and (5.3±1.7)points at 3 months after operation, and (4.1±1.4)points, (5.8±1.8)points and (5.3±2.2)points at the last follow-up. The postoperative Tegner score in all groups was significantly improved from that preoperatively (all P<0.01). The Tegner score in single half tunnel group was significantly lower than that in other two groups at 3 months after operation and at last follow-up (all P<0.05), but there was no significant difference between other groups (all P>0.05). In single half tunnel group, double half curved tunnel group and suture anchor group, the knee range of motion was (122.3±6.4)°, (121.7±7.1)° and (123.3±5.7)° at the last follow-up, which were significantly increased from (117.3±8.0)°, (115.3±7.9)° and (116.8±8.3)° at 3 months after operation (all P<0.05), with no significant difference among the three groups (all P>0.05). The postoperative complication rate was 10.0% (2/20) in single half tunnel group, 5.6% (1/18) in double half curved tunnel group, and 25.0% (5/20) in suture anchor group ( P>0.05). Conclusions:For patellar dislocation, MPFL reconstruction using single half tunnel, double half curve tunnel and suture anchor fixation have achieved satisfactory improvement of knee range of motion, but knee functional recovery is much better after double half curved tunnel fixation.