Study Of Age Level Inlfuencing The Treatment In The Evelopmental Dislocation Of Hip(DDH) By The Conservative Treatment Complicated With Avascular Necrosis (AVN) Of The Femoral Head

ObjectiveStudy of age level influencing the treatment in the developmental dislocation of hip bythe conservative treatment，through analyzing the imaging and clinical data of thedislocation of hips by the conservative treatment after a long—term follow up，anddiscuss age therapy criterion chosing of DDH expectant treatment.Datas and MethodsTo review and analyze the DDH children who accepted conservative treatment from2005，we totally get53children（77hips），3boys（6hips）and50girls （71hips）.According to the age level，all patients were divided into three treatment groups withthe principle of matching:≤12months、13-15months、≥16months. Make afollow-up for all the children at least one year on average，evaluate avascular necrosisof the femoral head with Salter criterion，and Tonnis criterion for the grade of thedislocation，Summary of clinical data and imaging results，analyze the discrepancybetween different age groups of DDH expectant treatment complicated with AVN. Chisquare test for count data and rank sum test for measurement data, the difference issignificant with P<0.05.Results30in77（40.0%）developed AVN，before12months，for the age，3in25（12.0%）developed AVN；for the13-15months，12in20（60.0%）developed AVN，above16months，15in32（46.9%）developed AVN. Through the chi square test，the differencebetween the three groups is significan（tχ~2=12.207，P=0.002），after a further pairwisecomparison between every two groups，difference between≤12months and13-15months is significant（χ~2=9.461，P=0.002），so is≤12months and（χ~2=6.369，P=0.012），but not for13-15months and≥16month（sχ~2=0.405，P=0.525）. Betweendifferent grades of the dislocation at each age level，however，there is no significancein≤12months group and13-15months group，but not in the≥16months group.Conclusions1The developmental dislocation of hip by conservative treatment complicated with avascular necrosis of the femoral head is relevant with age，grade of the dislocation，femoral head ossific nucleus. a personal scheme based on infant itself should beactually made.2Children after12months combined with Ⅲ degree of the dislocation are notsuitable for DDH expectant treatment.