Abstract: BACKGROUND: There is no unified clinical reference standard for the recovery of the plateau width during the operation of tibial plateau fracture, and there are few studies on its effect on the postoperative knee function at home and abroad.  
OBJECTIVE: To explore the anatomical relationship between adult lateral tibial plateau and lateral femoral condyle and its clinical significance about width reduction in Schatzker II tibial plateau fractures.
METHODS:  The X-ray films of knee joint of 148 normal adults (208 knees) in normal neutral position (normal knee group) and X-ray films of Schatzker II tibial plateau fractures of 58 cases (58 knees) (fracture group) from December 2019 to June 2021 in the Third Affiliated Hospital of Anhui Medical University were retrospectively analyzed. The lateral-most margins of the tibial plateau articular surface were defined as point A; the lateral femoral condyle articular surface was defined as point B; the lateral femoral epicondyle was defined as point C; the horizontal distances of A-B and A-C were measured separately; medial and lateral measurements to point A were recorded as (-) and (+). The A-C distance was recorded in the same way. They were grouped by sex and side factors, and the comparison between the groups was performed to find the anatomical relationship between the adult lateral tibial plateau and lateral femoral condyle. The Hospital for Special Surgery scale was performed for one year after surgery of Schatzker II tibial plateau fractures. After reduction, point A on the inside of point C was defined as group A and point A on the outside of point C was defined as group B; the knee function of group A and group B was compared.  
RESULTS AND CONCLUSION: (1) There was no significant difference in the mean A-B distance of the normal knee group between males and females (t=-1.86, P > 0.05). There was no significant difference in the mean A-C distance of the normal knee group between males and females (t=0.70, P > 0.05). There was no significant difference in the mean A-B distance of the normal knee group between the left side and the right side (t=-0.67,P > 0.05). There was no significant difference in the mean A-C distance of the normal knee group between the left side and the right side (t=1.09, P > 0.05). (2) The mean A-B distance of the normal knee group was (-3.60±0.84) mm and the mean preoperative A-B distance of the fracture group was (-5.28±1.16) mm; there was significant difference between groups (t=10.28, P < 0.05). The mean A-C distance of the normal knee group was (1.80±1.26) mm and the mean preoperative A-C distance of the fracture group was (1.09±2.18) mm; there were significant differences between groups (t=2.37, P < 0.05). (3) The mean Hospital for Special Surgery scale for one year after surgery was (83.05±2.04) points of group A and (75.97±1.91) points of group B; there were significant differences between groups (t=13.25, P < 0.05). (4) It is concluded that the anatomical position relationship between the lateral tibial plateau and the lateral femoral condyle in adults is relatively constant, and poor intraoperative reduction of the width of the tibial plateau is an important influencing factor of decreased knee function after surgery.

Key words: tibial plateau, width, tibial plateau fracture, knee joint function, fracture reduction