Clinical Efficacy Of Crowe Ⅰ-Ⅱ Developmental Dysplasia Of The Hip Treated With Tri-Lock Bone Preservation Stem In The Early Period

Objective:To discuss the clinical efficacy of total hip arthroplasty（THA）with posterolateral approach using Tri-Lock bone preservation stem（BPS）femoral stem in the early treatment of developmental dysplasia of the hip（DDH）.Methods:To retrospectively analyze the data of 55 CroweⅠ-Ⅱtype DDH patients（70hips）,including 14 males（19 hips）and 41 females（51 hips）of age from 26 to 78（57.79±11.34）who were admitted to the joint surgery department of Guizhou People’s Hospital during October 2014 to January 2020.All patients were treated with THA.According to the different femoral stems used,the patients were separated into two groups,which were the observation group（30 cases,36 hips using Tri-Lock BPS femoral stems）and the control group（25 cases,34 hips using Corail femoral stems）.We observed and compared the general information,operation time,intraoperative blood loss,postoperative hospital stay time,hemoglobin（HB）before and after the operation,and canal flare index（CFI）of those two groups.We assessed the stability of initial femoral shaft replacement in the first day after operation refer to the Mulliken standard and evaluated the whole therapeutic effect by visual analogue scale（VAS）scores according to the hip pain when the second day after operation and the Harris hip scores（HHS）acquired when 12 weeks after operation.Then,we compared the therapeutic effect and postoperative complications of the two groups.The absolute length differences of both lower limbs,the change of femoral anteversion（FA）,the bone mass preservation area of the widest part of lesser trochanter and greater trochanter,and the bone mass preservation volume between lesser trochanter and greater trochanter were respectively acquired from full-length X-ray film of both lower limbs and three-dimensional CT reconstruction image of hip in the pelvic anteroposterior position.Then the bone mass preservation situation was analyzed from the specific value of hip bone mineral density（BMD）.Results:All patients were followed up from 12 to 74 months with an average of 27.7months.There show statistical significances between the two groups in the preoperative data of CFI and friction interface（all the P values were<0.05）,while there were no statistically significant difference in gender,age,nationality,height,weight,body mass index（BMI）,side,Crowe classification and other general data（all the P values were>0.05）.The intraoperative blood loss,postoperative hospital stay time and postoperative HB absolute value between the observation group and the control group all existed statistically significant differences（P<0.05）,but there were no statistically significant differences in operation time,preoperative HB absolute value and HB loss（P>0.05）.The bone mass retention area at the widest part of the femoral trochanter[7.91（7.14,8.24）cm²,6.06（5.59,7.23）cm²],the bone mass retention area of the widest part of the greater trochanter of femur[（10.01±1.18）cm²,（8.50±1.89）cm²],and intertrochanteric bone mass retention volume[（31.09±3.12）cm³,（18.47±3.62）cm³]were statistically significant in the observation group compared to the control group（all the P values were<0.05）.There were statistically significant differences in the absolute length difference of both lower limbs and the pain of distal thigh between the two groups（P<0.05）.There was no statistically significant difference in the initial stability of femoral stem,the change of FA,the VAS of hip pain on the second day after operation,the HHS on the 12^th week after operation,and other surgical complications（all P values were>0.05）,but the adjustment range of FA is relatively wide.At the time of clinical follow-up,the changes of BMD in hip area 1 and 7 were compared between the two groups showing statistically significant differences（P<0.05）.Conclusion:When through the same approach（posterolateral approach）,using Tri-Lock BPS femoral stem to treat DDH has the same clinical effect as that of using Corail femoral stem.However,the application of Tri-Lock BPS femoral stem can relatively reduce the occurrence of surgical trauma and postoperative complications and make patients satisfactory and FA adjustment space is relatively abundant.Moreover,it can effectively retain the proximal femur bone mass and delay the speed of bone loss at the same time.Especially for the relatively young DDH patients with champagne fluted medullary cavity stenosis,while effectively preserving bone mass for the expected revision surgery,the improvement of the absolute length difference of both lower limbs is better,so that the patients can obtain satisfactory hip movement,and the relative treatment effect is significant.