▁v asc ular ▁ins ult ▁ ▁F ault y ▁m atur ation ▁of ▁the ▁cart il age ▁and ▁met ap hy se al ▁b one ▁of ▁the ▁fem oral ▁neck ▁ ▁C lin ical ▁feature : ▁presents ▁after ▁the ▁child ▁has ▁started ▁walking ▁but ▁before ▁six ▁years ▁of ▁age . ▁Usually ▁associated ▁with ▁a ▁pain less ▁hip ▁due ▁to ▁m ild ▁ab duct or ▁weak ness ▁and ▁m ild ▁lim b ▁length ▁dis cre p ancy . ▁ ▁If ▁there ▁is ▁a ▁bil ater al ▁invol vement ▁the ▁child ▁might ▁have ▁a ▁w add ling ▁g ait ▁or ▁tr end elen burg ▁g ait ▁with ▁an ▁increased ▁lum bar ▁lord osis . ▁The ▁greater ▁tro chan ter ▁is ▁usually ▁prominent ▁on ▁pal p ation ▁and ▁is ▁more ▁proxim al . ▁Rest rict ed ▁ab du ction ▁and ▁internal ▁rotation . ▁ ▁X - ray : ▁decre ased ▁neck ▁sh aft ▁angle , ▁increased ▁cer vic of em oral ▁angle , ▁vertical ▁phys is , ▁short ened ▁fem oral ▁neck ▁decrease ▁in ▁fem oral ▁ante version . ▁HE ▁angle ▁( H il gen ri ener ▁e pi phy se al ▁angle - ▁angle ▁subt ended ▁between ▁a ▁horizontal ▁line ▁connecting ▁the ▁tri rad iate ▁cart il age ▁and ▁the ▁e pi ph ysis ); ▁normal ▁angle ▁is ▁< 3 0 ▁degrees . ▁ ▁Tre at ment : ▁HE ▁angle ▁of ▁ 4 5 – 6 0 ▁degrees : ▁observation ▁and ▁periodic ▁follow ▁up . ▁ ▁Ind ic ation ▁for ▁surg ery : ▁HE ▁angle