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 analyze the semen quality parameters of sperm donor volunteers, so as to provide insights into male infertility control and related research. Methods: A total of 155 sperm donors were recruited from the Human Sperm Bank of Zhejiang Province using the convenience sampling method from January to March 2021. Demographic information were collected through questionnaire surveys. Semen were collected, and parameters including semen volume, sperm concentration, total number of sperm, forward motility rate and total sperm viability were measured. Semen quality was evaluated according to the WHO Laboratory Manual for the Examination and Processing of Human Semen. : Results Conclusion There were 20.65% of the 155 sperm donors with unqualified semen, and the unqualified rates of forward motility rate and total sperm viability were relatively high.