| Objective:Open reduction plus Dega osteotomy is currently the main treatment method for Developmental dysplasia of the hip of walking age children.Simultaneous osteotomy of the proximal femur,can reduce pressure on the femoral head and acetabulum,and increase stability of the hip joint.However,the necessity of the proximal femur osteotomy is still widely disputed.The purpose of this study is to compare the clinical and radiographic outcomes of DDH patients treated with open reduction plus Dega pelvic osteotomy,with or without proximal femoral osteotomy,in order to determine the necessity for the simultaneous osteotomy of the proximal femur with the procedure.Methods:Retrospective analysis of 67 patients(80 hips)who had had open reduction plus Dega pelvic osteotomy in our department from January 2011 to December 2015,with a minimum of 2 years follow-up was carried out.The dislocated height of each dysplastic hip was pre-operatively classified according to T?nnis classification method of the hip joint.There were 0 type Ⅰ,36 type Ⅱ,2 type Ⅲ and 10 type Ⅳ hips in the proximal femoral osteotomy group,while there were 1 type Ⅰ,27 type Ⅱ,1 type Ⅲ,and 3 type Ⅳ hips in the non-proximal femoral osteotomy group.Because of the small number of T?nnis typeⅣcases in the non-proximal femoral osteotomy group(3 hips),these cases were not included in the statistical analysis.This study was based on the 58(67 hips)T?nnis typesⅠ,ⅡandⅢpatients of both groups.There were 33 patients(38 hips)in the femoral osteotomy group of which 2were males and 31 were females,with an average operative age of 25 months(15 to46 months).13 left,15 right and 5 bilateral hips were involved.There were 25patients(29 hips)in the femoral non-osteotomy group,of which 5 were males and20 were females,with an average operative age of 19 months(6 to 32 months),involving 10 left,11 right and 4 bilateral hips.Acetabular index(AI)and Neck-shaft angle(NSA)were measured on the preoperative pelvic anteroposterior(AP)radiographs.AI and Centre-edge angle(CEA)were also measured on the post-operative pelvic AP radiographs within one week post-operation.At the last follow-up,full length radiograph of both lower limbs was performed.Skeletal leg length of both lower extremities was used to measure the difference in leg length for Limbs length discrepancy(LLD).On the AP pelvic radiograph,AI,CEA,NSA,Alsberg angle,and the distance between the Articulo-trochanteric distance(ATD)were also measured at the last follow-up.The improvement in AI,the change in CEA and NSA were calculated at the last follow-up,as follows:ΔAI(Postoperative AI-last follow-up AI),ΔCEA(Postoperative CEA-last follow-up CEA),andΔNSA(Postoperative NSA-last follow-up NSA).The Centre-head distance discrepancy(ΔCHDD)was measured and calculated according to the difference between the two groups of unilateral DDH hips at the last follow-up.The maximal femoral head diameter ratio(r value)between the affected side and normal side was also measured and calculated at the last follow-up.The height to width index(HWI)of the femoral head bone was also measured and calculated in the two groups at the last follow-up.Severin grading system was used to classify the hip joints in the last follow-up radiographs.Grades I and Ⅱ were regarded as excellent.Mc Kay’s classification was used to evaluate the hip joint function on last follow-up,and the proportion of redislocation of hip joint was evaluated.Salter standard was used to assess for Avascular necrosis(AVN)of the femoral head,and classified according to Kalamchi-Mac Ewen standards.Statistical analysis of the above measured parameters and evaluation results was done using the independent samples t-test,Mann-Whitney U test,X~2test and Fisher’s exact test of X~2.Results:All 58 patients(67 hips)were followed for an average of 41 months(24 to 70 months).The mean follow-up time in both osteotomy and non-osteotomy groups were 43.2 months±13.3 months and 37.9 months±10 months(p=0.067),respectively.There was no significant statistical difference in gender and affected side between the two groups pre-operatively(p=0.107 and 0.993,respectively).With regards to the morphological parameters of the acetabular side,the pre-operative,postoperative,and final follow-up AI in the osteotomy group were respectively 36.7°±7.0°,19.5°±7.9°,14.2°±8.0°,with an improvement of 5.3°±9.2°in AI.In the non-osteotomy group,the pre-operative,postoperative,and final follow-up AI were respectively 38.1°±5.9°,28.2°±7.6°,23.2°±6.6°,with an improvement of 5.0°±4.7°in AI(p=0.855).In the osteotomy group,the postoperative and last follow-up CEA were 32.7°±9.0°and 26.6°±8.7°respectively,with a change of 6.2°±7.7°in CEA.In the non-osteotomy group,the post-operative and final follow-up CEA were 25.2°±11.6°,16.2°±8.4°,respectively,with a9.0°±11.7°change in CEA.However,there was no significant difference in CEA change between the osteotomy and non-osteotomy groups(p=0.268).As to the morphological development of the proximal femur,the preoperative and final follow-up NSA in the osteotomy group were 144.7°±9.9°and 148.0°±8.4°respectively,with a 3.2°±13.0°change in NSA.In the non-osteotomy group,the preoperative and final follow-up NSA were 142.9°±7.8°and 147.6°±8.2°respectively,with a 4.7°±10.1°change in NSA.There was however no statistical difference in change in NSA in both groups(p=0.606).The Alsberg angles at final follow-up in both osteotomy and non-osteotomy groups were 76.9°±7.8°and76.2°±6.9°respectively(p=0.721),The ATD values at last follow-up were24.0mm±5.3mm and 26.8mm±6.0mm(p=0.051)respectively.As to the changes in the acetabular joint,there was a 6.5%±7.9%and 3.0%±7.1%change in CHDD in the unilateral DDH osteotomy and non-osteotomy groups respectively(p=0.118).As to the morphological parameters of the epiphysis of the femoral head,the last follow-up HWI in the osteotomy and non-osteotomy groups were 55.7%±6.7%and 52.8%±6.1%respectively(p=0.068),and the maximum femoral head diameter ratio(r values)at last follow up of the dislocated side and normal side in the unilateral DDH group were 1.12±0.13 and 1.19±0.15 respectively(p=0.073).At the last follow-up,r≤1.15 in 14 hips and r>1.15 in another 14 hips in the osteotomy group,while r≤1.15 in 6 hips and r>1.15 in 15 hips in the non-osteotomy group.There was however no statistically difference in distribution between the two groups(p=0.131).The LLD in the unilateral DDH group at the last follow-up was 5.2mm±7.1mm and 9.4mm±4.6mm in the osteotomy and non-osteotomy groups respectively.When the femur was not osteotomized,the lower extremity length difference was more obvious(P=0.024).At final follow-up time of the osteotomy group,4 hips were graded as grade 1,27 as grade 2 and 7 as grade 3 according to Severin radiographic evaluation criteria,with a good and excellent rate of 81.6%(31/38),while in the non-osteotomy group,8 hips were graded as grade 1,10 as grade 2,11 as grade 3,with a good and excellent rate of 60.7%(18/29).However,there was no statistical difference in outcomes between the two groups(p=0.074).According to Mc Kay’s hip joint function evaluation method,22 hips in the osteotomy group had excellent results,15 hips had good results,1 hip had fair result at the time of final follow-up.The good and excellent rate was 97.4%(37/38).In the non-osteotomy group,23 hips had excellent results,5 hips had good results and 1 hip had fair result.The rate good and excellent rate was 96.6%(28/29).There was however no statistical difference in the good and excellent rate between the two groups(p=0.846).No secondary dislocation was found in this study.According to Kalamchi-Mac Ewen classification method,there were 10 hips with type Ⅱ AVN and 1 hip with type Ⅳ AVN in the femur osteotomy group,while there were 6 hips with type Ⅱ AVN in femur non-osteotomy group.The incidence of AVN in the femur osteotomy group and femur non-osteotomy group were 28.9%and 20.7%,respectively.The difference was however not statistically significant(X~2=0.592p=0.442).Conclusions:Proximal femoral osteotomy is unnecessary when open reduction plus Dega pelvic osteotomy is done in patients of walking age,presenting with T?nnis type Ⅲ or below dislocation of the hip. |
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