The Influence Of The Amount Of Correction On The Posterior Tibial Slope And Patella Height In OWHTO

ObjectiveWe made a systematical research on 35 patients with knee osteoarthritis(KOA)treated with open-wedge high tibial osteotomy(OWHTO).Evaluating the improvement of patients’ joint function and pain relieve postoperatively.We analysised the influence of the amount correction on posterior tibia slope(PTS)and patellar height(PH),trying to maintain unchange of PTS and PH postoperatively and build up theoretical basis.MethodsWe collected patients’ data who were treated with OWHTO in our hosptial from 12th 2015 to 12th 2017.According to inclusion criteria and exclusion criteria,we collected all patients’ basic information(name,gender,height,age,weight and operation side)and the knee joint KSS score,VAS score and the HSS score,trying to evaluating pain relieve and function improvement.We recorded the the amount of correction and divided the patients into 3 groups according to the common average correction:group A(7°～9°)and group B(10°～12°),group C(13°～15°).Using the Huahai-imaging system to measure the difference value of PTS and PH(IS index,BP index)before and after surgery.In addition,adopting the one-way analysis of variance to explore whether the amount of correction and the difference value of PTS,IS and BP have statistically significant between 3 groups.ResultsThis study consisted of 40 patients,3 of them did not get effective follow-up,2 patients participated in other research projects at the same time.According to weed out the standard,35 patients(38 knees)were included as final research objects eventually.The average follow-up time is 10±5.4m(25.5～5.2m).There were 22 females and 13 males,namely,group A had 13 knees(12 patients),group B had 13 knees(11 patients),group C had 12 knees(12 patients).The average age of patients was 61.5±9.8y(19～77 years).The duration of the disease was 4.7±3y(1.2～13 years)and the average BMI was 23.82±2.16.There were 18 right knees,14 left knees and 3 bilateral knees.In all patients,the average KSS score was 60.4±7.3 points before surgery and increased to 83.2±6.9 ponits at final follow-up.Preoperative averaged VAS score was 5.2±1.1 points and decreased to 1.2±1.0 points postoperatively.HSS score was increased from 59.4±7.2 points to 87.7±5.7 after surgery.There was a statistically significant difference between the preoperative and postoperative scores(P<0.05).According to the results of HSS score,there were 20 excllent knees(51.4%),11 good knees(28.6%),5 medium knees(14.3%),2 unsatisfied knees(5.7%).The rate of excllent-good knee reached 80%.The IS index reduced from 0.98±0.11 to 0.81 ±0.13 after surgery.And BP index reduced from 0.76±0.13 to 0.65±0.1 postoperatively.While PTS increased from 7.82°±0.93°to 10.76°±0.93°after surgery.They all have statistically significant difference(P<0.05).The one-way analysis of variance was performed in 3 groups.As for IS difference(F=85.922,P<0.05),there was no statistically difference between group A and group B(P=0.112).While,Group C had statistical difference with group A and group B(P<0.05).As for BP difference(F=73.518,P<0.05),there was no statistically difference between group A and group B(P=0.235).While,Group C had statistical difference with group A and group B(P<0.05).In terms of postoperative PTS difference(F=70.883,P<0.05),the Bonferroni test found statistical differences between 3 groups(P<0.05).Three patients(3 knees)had lateral hinge fractures,2 patients(2 knees)had superficial wound infection.All patients mentioned above were satisfied after treatment.ConclusionThe OWHTO is one of the effective treatment methods for KOA.This surgery can effectively relieve knee pain and improve joint function.The OWHTO would cause the changes of PTS and PH.The changes of PTS were positively correlated with the amount of correction.And the changes of PH were negatively correlated with the amount of correction.Especially when the correction is larger(>12°),PH would reduce more apparent.