Significance of changes in posterior tibial slope plateau after unicompartmental knee arthroplasty
Hu Zhenghao, Chen Wang, Feng Shuo, Zhang Leshu, Chen Xiangyang
Department of Joint Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221000, Jiangsu Province, China
Abstract: BACKGROUND: Previous studies have tended to study the optimal posterior tibial slope of tibial plateau after unicompartmental knee arthroplasty, ignoring the comparison with the preoperative angle to explore the impact of the degree of change on the clinical efficacy.
OBJECTIVE: To investigate the changes of posterior tibial slope and their influence on short-term efficacy after unicompartmental knee arthroplasty.
METHODS: Totally 65 patients (67 knees) who underwent Oxford unicompartmental knee arthroplasty for medial osteoarthritis in Affiliated Hospital of Xuzhou Medical University from January 2016 to June 2021 were selected as the research subjects. The groups were divided according to the difference between postoperative minus preoperative posterior tibial slope. Positive value was increased posterior slope; negative value was decreased posterior slope. Group A: posterior slope decreased > 2°, Group B: posterior slope changed ≤ 2°, Group C: posterior slope increased > 2°. The hospital for special surgery knee score, Oxford knee score, range of motion, and forgotten joint score were recorded and compared in three groups.
RESULTS AND CONCLUSION: (1) A total of 65 patients (67 knees) were included in this study. According to the change of the average posterior tibial slope, they were divided into three groups, with 13 knees in group A, 38 knees in group B, and 16 knees in group C. (2) There was no significant difference in baseline data such as age, gender and prosthesis size among the three groups (P > 0.05). (3) Compared with the knee range of motion at the last follow-up after operation, the knee range of motion in group C was significantly greater than that in group A (P=0.014) and group B (P=0.032). (4) The Oxford knee score of group B at last follow-up was significantly lower than that of group C (P=0.004). (5) In the last follow-up, artificial joint amnesia index in the group B was significantly better than that in the group A (P=0.012). (6) It is indicated that patients with a change in posterior tibial slope of ≤ 2° after unicompartmental knee arthroplasty can obtain better short-term clinical efficacy. Within unicompartmental knee arthroplasty, individualized and precise osteotomy on the tibial side should be emphasized.
Key words: posterior tibial slope, unicompartmental knee arthroplasty, osteoarthritis, range of motion, forgotten joint score