Effect Of The Changes Of Femoral Head Rotational Center In The Treatment Of CroweⅡ And Ⅲ DDH In Adult With THA On Early Efficacy

Objective: The influence of changes in rotational center of femoral head in Crowe Ⅱ and Ⅲ type adult DDH total hip replacement on the early curative effect was discussed and analyzed based on the relevant parameters of hip joint and their ratios.Methods: The clinical data of 42 patients with Crowe type II and III DDH who underwent the first total hip arthroplasty(THA)from May 2014 to March 2017 in the department of bone,affiliated hospital of Zunyi medical college were collected as the study group,including 10 males(10 hips),32 females(32 hips),aged 20 to 68 years,with an average age of 49.5 years,including 22 Crowe type II(22 hips)and 20 Crowe type III(20 hips).the clinical data of 50 healthy adults(50 hips)during the same period were selected as the control group,including 15 males(15 hips)and 35 females(35 hips)Adobe illustrator cc 2018 22.0 was used to measure the weight moment arm(BWLA),abduction muscle arm(ALA),femur eccentricity(FO),femur lesser trochanter height(HFT)and femoral head rotation center height(HRC)of the study group(including preoperative and postoperative)and the control group on the standard pelvic orthophoto.the ratio of weight moment arm to abduction muscle arm(BWLA / ALA),the ratio of weight moment arm to femur eccentricity(BWLA / FO)and the ratio of femoral head rotation center height to lesser trochanter height(HRC / HFT)were calculated to collect data and record the pre-operation of the study group.Results: In 50 control group(healthy adults),the ratio of BWLA and ALA was 1.93±0.18,and the 95% confidence interval was(1.88,1.98),the ratio of BWLA and FO was 2.54±0.31,and the 95% confidence interval was(2.45,2.63),and the ratio of HRC and HFT was 0.33±0.48,and the 95% confidence interval was(0.31,0.34).In the 42 study groups,the ratio of BWLA and ALA before and after THA respectively was(3.22±0.46,2.07±0.34),the ratio of BWLA and FO severally was(4.45±0.87,2.55±0.43),and the ratio of HRC and HFT respectively was(1.36±0.46,0.63±0.21).After one-way analysis of variance,there was a statistically significant difference in the above three ratios of hip parameters between the control group and the study group preoperative and postoperative(P<0.01).Due to inconsistent variance(P<0.05),we use the Tamhane T2 test to two-by-two compare further.There was a statistically significant difference in the ratio of hip parameters between the THA group and the control group before and after THA(P<0.01).In the study group,the above ratios of hip parameters were statistically different from those of the control group preoperative and postoperative(P<0.01).The ratios of BWLA and FO and BWLA and ALA in the study group postoperative were not statistically different from those in the control group(P>0.05).There was a statistically significant difference in the ratio HRC and HFT after THA compared with the control group(P<0.01).The difference in the preoperative Harris score between study group Crowe Ⅱ and Ⅲ DDH do not have statistical significance(P>0.05),and the postoperative Harris score was significantly higher than preoperative.The difference between the preoperative Harris score and the postoperative Harris score at the end of follow-up have statistically significant(P<0.05).However,on 3 months,6months and 12 months after surgery,the mean Harris scores between Crowe Ⅱ and Ⅲ DDH have no significant differences(P>0.05).Trendelenburg sign in all patients of study group was positive before surgery,and only three patients was remain positive in 12 months after operation.All cases showed no dislocation,joint infection,prosthesis loose,periprosthetic fracture and neurovascular injury during follow-up.All patients were satisfied with short-term curative effect.Conclusion: Firstly,in the treatment of Crowe Ⅱ and Ⅲ DDH in adult with THA,the femoral head rotation center displaces appropriately on upper side(HRC/HFT<0.8)and avoids to move outward(BWLA/FO<2.6 or BWLA/ALA<1.98),which have no significant impact on the early postoperative hip joint function,but the long-term efficacy needs further follow-up observation.Secondly,using the ratio of hip of related hip joint parameters can reduce the differences caused by changes in parameters such as perspective magnification,gender,height,and region.