| Objective:Morphological change of proximal femur is a common manifestation after treatment of children with developmental dysplasia of the hip（DDH）,but the causes of which are not clear.This study intends to investigate the possible factors leading to the morphological changes of proximal femur after DDH treatment by multi-factor regression.Methods:The clinical data of 83 children with DDH treated in our hospital from January2013 to June 2017（all with unilateral disease）were retrospectively analyzed.General data of all children were recorded,including surgical method（closed reduction,open reduction alone,open reduction combined with pelvic and femoral osteotomy）,surgical side,surgical age,preoperative dislocation degree（IHDI classification）,gender,etc.At the same time,parameters of different types of morphological abnormalities in proximal femur were recorded at the last follow-up,such as the Height to width index（HWI）<0.357,Alsberg Angle>81°,femoral head epiphysis nucleus enlargement more than 15%of the normal side;At the same time,the indexes related to the degree of acetabular reduction after surgery were compared,such as the center-edge angle of wiberg（CEA）and acetabular head index（AHI）at the last follow-up of all children were measured in the forward pelvis and frog position,center-head distance discrepancy（CHDD）.Finally,the relationship between the incidence of the three morphological abnormalities and surgical methods,surgical age,gender,surgical side and preoperative dislocation degree was analyzed and compared.Results:The 83 children included 9 males,74 females,49 of left DDH,34 of right DDH,and preoperative dislocation（IHDI classification）in 8 cases of typeⅡ,40 cases of typeⅢ,and 35 cases of typeⅣ.36 cases were treated by closed reduction（CR）,20 cases by simple open reduction（SOR）,and 27 cases by open reduction combined with osteotomy of pelvis and femur（ORO）.The mean follow-up time was 48.5 months.At last follow-up,there were 9 patients with HWI<0.357,16 patients with Alsberg Angle>81°,and 34patients with femoral head enlargement exceeding 15%of normal side.The results showed that CEA,AHI and CHDD had no significant differences in the degree of reduction at the head and acetabulum between groups with HWI<or≥0.357,Alsberg Angle>81°or≤81°,and femoral head enlargement>or≤15%.Logistic regression analysis showed that the incidence of HWI<0.357,Alsberg Angle>81°was not correlated with surgical age,surgical method,surgical side,preoperative dislocation degree,and patient gender(Pmin=0.091).The incidence of femoral head enlargement exceeding 15%on the normal side was correlated with the difference of surgical method（P<0.001,OR=11.123,95%CI 4.173-29.649）and surgical side（P=0.011,OR=7.182,95%CI 1.570-32.849）.In open reduction patients,the difference of the surgical side had a statistically significant effect on the enlargement of the femoral head（P=0.016,OR=16.173,95%CI 1.698-154.08）,and was independent of whether the open reduction was combined with femoral and pelvic osteotomy,age of surgery,gender,and degree of dislocation before surgery.Conclusion:Femoral head enlargement is a common morphological anomaly after DDH treatment,and open reduction is a risk factor for its occurrence.The risk of femoral head enlargement in open reduction is about 11 times that in closed reduction.This complication should be fully considered when selecting open reduction for DDH. |
