| Objective:To discuss the imaging results and clinical efficacy of high placement of the acetabular component in total hip arthroplasty in secondary hip osteo arthritis to adult unilateral Crowe type II developmental hip dysplasia.Methods:All the patients were reviewed in the department of orthopedics of the second affiliated hospital of fujian medical university from November 2013 to July 2018.20 patients with secondary HOA to unilateral Crowe II DDH who received the treatment of initial THA were selected as the research group,in which the acetabular component was placed above the anatomical rotation center(high hip center group,HHC).During the same period,20 patients were randomly selected from patients diagnosed as unilateral aseptic necrosis of femoral head(Ficat ?)who received the treatment of initial THA as the control group,in which the acetabular component was placed in the anatomical rotation center(an atomical hip center group,AHC).All patients were taken standard anteroposterior pelvic X-ray preoperatively and 1 week postoperatively.All patients were follo wed up regularly in our hospital,and clinical indicators such as hip function and gait were recorded.The results of imaging comparison included:(1)The vertical distance of rotation center(The vertical distance between the rotation center of acetabulum or acetabular cup and the connecting line of the lower edge of bilateral teardrops);(2)The horizontal distance of rotation center(The horizontal distance between the rotation center of acetabulum or acetabular cup and the vertical line of inner edge of teardrop on the same side);(3)The difference in length of both lower limbs(The difference in the vertical distance between the lower edge of bilateral lesser trochanter and the connecting line of the lower edge of bilateral teardrops);(4)Femoral offset(The vertical distance between the rotation center of acetabulum or acetabular cup and the axis of the femoral shaft).The reconstruction standard for femoral offset were defined:Postoperative difference in bilateral femoral offset was less than or equal to 5mm;The standard for equal length of both lower limbs were defined:Postoperative difference in the length of both lower limbs was less than or equal to 5mm.The clinical efficacy analysis included:(1)Harris scores of the hip joint pre-operation and at the last follow-up;(2)Gait and Trendelenburg sign before operation and at the last followup;(3)Postoperative complications,such as aseptic loosening,dislocation of the joi nt,periprosthetic infection,fracture around the prosthesis,nerve or blood vessel injury,etc.Using T-test or ?2-test to statistically analyze the data that we mentione d above,comparing the imaging indexes and the difference of clinical efficacy between the two groups.Result:All patients were followed up for 7 to 63 months,an average of 38.6 m onths.(1)The results of imaging index:The vertical distance of rotation center of HHC:The normal side was 18.39±3.93 mm,postoperative side was 30.83±5.81 m m,analyzed by t-test,t=-8.440,P<0.01,the difference was statistically significant.The horizontal distance of rotation center of HHC:Pre-operation was 40.47±4.18 m m,post-operation was 34.82±3.92 mm,analyzed by t-test,t=5.381,P<0.01,the difference was statistically significant.The difference in length of both lower limbs of HHC:Pre-operation was-12.71±11.47 mm,post-operation was 0.01±9.59 mm,analy zed by t-test,t=-8.025,P<0.01,the difference was statistically significant.The differ ence in length of both lower limbs of AHC:Pre-operation was-5.86±5.36 mm,post-operation was 3.15±5.54 mm,analyzed by t-test,t=-6.966,P<0.01,the difference was statistically significant.Postoperative difference in length of both lower limbs:HHC was 0.01±9.59 mm,AHC was 3.15±5.54 mm,analyzed by t-test,t=-1.270,P>0.05,there was no significant difference.Postoperative difference of bilateral femoral offset:HHC was 0.84±6.05 mm,AHC was 1.49±4.29 mm,analyzed by t-test,t=-0.392,P>0.05,there was no significant difference.The incidence of unequal lengt h of lower limbs after surgery:HHC was 50%,AHC was 45%,analyzed by ?2-te st,?2=-0.100,P>0.05,there was no significant difference.Postoperative unreconstructed rate of femoral offset:HHC was 35%,AHC was 30%,analyzed by ?2-test,?2=-0.114,P>0.05,there was no significant difference.(2)The results of clinical effi cacy analysis:The Harris scores of HHC:Pre-operation was 39.25±3.39 mm,last postoperative follow-up was 90.60±2.28 mm,analyzed by t-test,t=-89.963,P<0.01,thedifference was statistically significant.The Harris scores of AHC:Pre-operation was 41.00±3.20 mm,last postoperative follow-up was 91.70±1.81 mm,analyzed by t-test,t=-62.733,P<0.01,the difference was statistically significant.The Harris scores at last postoperative follow-up:HHC was 90.60±2.28 mm,AHC was 91.70±1.81 mm,analyzed by t-test,t=-1.690,P>0.05,there was no significant difference.Patients in HHC had claudication and positive Trendelenburg sign before surgery,afte r treatment of THA,they had negative Trendelenburg sign at the last postoperati ve follow-up,with good gait and no claudication.Conclusions:1.The results showed that the rotation center of acetabular cup in HHC moved up and inward compared with the healthy side,which was in line with the principle of high acetabular reconstruction and medialisation of the a cetabular component.2.All patients in the two groups had preoperative shortenin g of the affected limbs,which was more severe in HHC.The affected limbs of the two groups were extended postoperatively,and the difference was not statisti cally significant.The results showed that high placement of the acetabular comp onent in THA could correct unequal length of lower limbs of Crowe type? DDH,and the clinical effect is satisfactory.3.Compared with pre-operation,postoper ative hip joint function of the two groups was improved,and the difference was not statistically significant.The results showed that high placement of the aceta bular component in THA could obviously improve the hip function of Crowe type? DDH. |
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