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 investigate the relationship between fragment size of ulnar coronoid process fracture and patient prognosis.Methods:A retrospective study was conducted of the 34 patients who had been treated at Department of Orthopaedics, The Second Hospital Affiliated to Lanzhou University for fracture of ulnar coronoid process combined with elbow dislocation from July 2016 to December 2020. They were assigned into 2 groups according to their different treatments. In the surgery (internal fixation) group of 23 cases, there were 15 males and 8 females, aged from 22 to 71 years; in the conservative treatment group of 11 cases, there were 8 males and 3 females, aged from 38 to 78 years. Preoperatively, the sizes of coronoid process and fracture fragments were measured by elbow CT scan and 3D reconstruction, and a size-weighted ratio Z (%) corresponding to the fragment of coronoid process fracture was calculated. At the last follow-up, American Hospital for Special Surgery total elbow scoring system (HSS2) score was used to assess their therapeutic efficacy, the correlation between the ratio Z and HSS2 score for elbow function was calculated, and complications were recorded.Results:There were no significant differences between the surgery and conservative treatment groups in gender or age ( P>0.05). All the 34 patients were followed up for 18 to 54 months (average, 36.7 months). At the last follow-up, the HSS2 score was 93.77±0.84 (from 82 to 98) for the surgery group and 86.00±1.42 (from 78 to 90) for the conservative treatment group; the complications rate was 13.04% (3/23) for the former and 63.64% (7/11) for the latter. There was a linear relationship between the size-weighted ratio Z of the coronoid fracture fragment and the HSS2 elbow function score in the surgery group ( P<0.01). The linear regression equation between them was: y=99.44-0.121x ( r2=0.86, P<0.01). There was a linear relationship between the size-weighted ratio Z of the coronoid fracture fragment and the HSS2 elbow function score in the conservative treatment group ( P<0.01). The linear regression equation between them was: y=89.46-0.144x ( r2=-0.91, P<0.01). When a HSS2 elbow joint function score 90 was substituted into both linear regression equations, the results were x=78.02 for the surgery group and x=3.75 for the conservative treatment group. Conclusions:Conservative treatment may not lead to a satisfactory prognosis for the patients with coronoid process fracture whose size-weighted ratio of fracture fragment is larger than 3.75. Open reduction and internal fixation usually leads to a satisfactory prognosis for those whose size-weighted ratio of fracture fragment is smaller than 78.02.