Background The posterior tibial slope (PTS) is crucial in knee joint stability and in maintaining the natural movement of the knee. An increase in the PTS is associated with various knee pathologic conditions, such as anterior cruciate ligament (ACL) injury and anterior tibial translation (ATT). In the present study, we aimed to establish native medial and lateral PTS values for adult Saudis and to identify any association between PTS and gender, age, and body mass index (BMI). Materials and methods A total of 285 consecutive, normal, magnetic resonance imaging (MRI) studies of the knee were included in the study. The PTS was measured using the proximal anatomical axis of the tibia. The Kruskal-Wallis test was used to compare the medial and lateral PTS angles between age groups. The difference between the medial and lateral posterior tibial slopes was assessed using the Wilcoxon signed-rank test. The Mann-Whitney U test was performed to compare the medial and lateral PTS angles between men and women. Age, gender, and BMI were analyzed by multivariate linear regression to determine whether they positively predict the medial and lateral PTS angles. Results The mean physiological medial PTS was 5.86 ± 3.0° and 6.61 ± 3.32°, and the lateral PTS was 4.41 ± 3.35° and 4.63 ± 2.85° in men and women, respectively. This difference showed no statistically significant gender dimorphism (p > 0.05). The medial PTS was significantly larger than the lateral PTS (p < 0.0001). There was no statistically significant difference in the medial and lateral PTS angles between age groups (p > 0.05). Higher BMI was significantly associated with a steeper medial PTS (p = 0.001). Conclusions This study provided native values for medial and lateral PTS angles in Saudis, which can assist surgeons in maintaining normal knee PTS during surgery. The PTS was not influenced by age. The medial PTS was significantly larger than the lateral PTS in men and women. The PTS showed no significant gender dimorphism. BMI was significantly associated with the medial PTS.

Aim The present study aimed to establish the normal range of the posterior tibial slope (PTS) angle in the Saudi adult population and to identify whether there was an association between the angle and gender or age. Materials and methods A total of 524 normal knee radiographs of 410 patients aged 18-85 years were included in the study. The PTS was measured using the anterior tibial cortex method. Data were matched with gender and age for statistical analysis. Results The mean physiological PTS angle was 13.6 ± 3.4˚ (range: 3.8-23.9˚). Age and gender did not influence the PTS value (P >0.05). The two-way analysis of variance (ANOVA) test showed no interaction effect between age and gender on the PTS (P >0.05). Conclusions This study provided a reference range for the normal PTS among Saudis, which can assist in decision-making during different knee procedures. The PTS value did not significantly differ between male and female subjects, and there was no significant association between the PTS angle and age.

Objectives The geographical incidence of tumours is usually influenced by the environment, race, and culture. This study aimed to report the incidence and differences in tumour type, site of origin, and mortality across gender, regions, age, and the different characteristics of tumour types. Methods This retrospective cohort study included all patients diagnosed with primary bone sarcomas from January 1, 2013, to December 31, 2017. Frequencies and percentages were generated for categorical variables. Means and standard deviations were calculated for quantitative variables. A chi-squared test was used to detect differences among categorical variables. Student-t, ANOVA, and Tukey tests were used to detect differences among quantitative variables. Lastly, we calculated the incidence of each tumour type. Results Of 451 patients, 248 (55%) had osteosarcomas; 160 (35.5%) had Ewing's sarcoma, and 43 (9.5%) had chondrosarcoma. The incidence was 1.56 cases per 1,000,000 per year for osteosarcoma, 0.95 cases per 1,000,000 per year for Ewing's sarcoma, and 0.27 cases per million per year for chondrosarcoma. The three-year survival rate was 82.30%. Significant differences in tumour type, origin site, and three-year survival across age and gender were detected. Similarly, significant differences were also noted in origin site, grade, basis of diagnosis, and lateralisation across tumour types. Conclusions In our study, the observed bone sarcoma incidence rates were lower than the ones reported worldwide. Understanding the pattern of tumour behaviour in the region will help develop a risk and response-based treatment plan for early decision-making.