The Influence Of The Greater Trochanter Drilling,Limb Pain And Physical Activity On Neck-shaft Angle And Femoral Anteversion After Open Reduction For Developmental Dysplasia Of The Hip In Rats

ObjectiveCoxa valga may sometimes occur as a complication of surgery for developmental dysplasia of the hip.It has been assumed that damage to the trochanteric growth plate,limb pain and physical activity may influence femoral neck shaft angle,but no experiments have confirmed it.The aim of this study was to corroborate the relationship between transphyseal damage and coxa valga.MethodsAfter operating open reduction on DDH hips in rats,transphyseal drilling model,limb pain model and PA model were operated.Neck-shaft angle and femoral anteversion were measured.this study explored the influence of transphyseal damage,limb and physical activity on neck-shaft angle and femoral anteversion after open reduction for DDH in rats.The legs and hips were fixed in the extension and adduction position in 90 neonatal Sprague Dawley(SD)rats by adhesive tape for 10 days.84 left dysplastic hips(84/90),verified on anteroposterior pelvic radiographs,were randomized.Trochanter trauma group(21 left hips)were treated with transphyseal drilling and open reduction at the age of 1 month.Limb pain group(21 left hips)were treated with the model of left plantar caustic burning and open reduction.Physical active group(22 left hips)were treated with the model of physical activity and open reduction.And the control group(20 left hips)only underwent open reduction.All the rats were raised in the same condition and sacrificed 1 month after operation,and 84 left femoral speciments were scanned and input into computers for measuring to work out neck-shaft angle and femoral anteversion.ResultsMean neck-shaft angle in the transphyseal trauma group(130.56±3.44)was larger than the control group(126.57±6.04,P=0.015).Mean neck-shaft angle in the limb pain group(131.83±3.74)was larger than the control group(P=0.002).Mean neck-shaft angle in the physical active group(120.42±2.90)was larger than the control group(P=0.015).No differences between groups were found for femoral anteversion(P>0.05).ConclusionDamage to the trochanteric growth plate at the time of operation for DDH,limb pain postoperatively was associated with larger neck-shaft angle.Moderate physical activity after surgery was associated with smaller neck-shaft angle.Improved understanding of these relationships could help in reducing the incidence of coxa valga and improving prognosis in DDH children.