Slipped Upper Femoral Epiphysis-MRI

14 yr old boy with history of trauma presents with limp and MRI shows slipped capital femoral epiphysis (posteriorly) with diffuse ill-defined marrow edema and cranial migration of the distal fragment with femoracetabular alignment maintained.

 Teaching points by Dr MGK Murthy, Mr Hari Om, Mr Charles

1.    Most common adolescence age group abnormality of hip joint and primary cause of early OA. Usually misdiagnosed early on, more in boys than girls.  It can be spontaneous or traumatic.

2.    Xray particularly AP Pelvis and Lateral frog-leg   views show slip better. Widening of physis , demineralization and Metaphyseal blanch(blush) sign (opacity on X-ray)  are present 

3.    SUFE(Slipped Upper Femoral Epiphysis) grading is made on AP and true lateral  Projections .

4.    On AP Line along the superior margin of femoral neck (kleins)should intersect the lateral corner of Epiphysis. In SUFE, Metaphysis divides in to thirds (mild=lateral edge of epiphysis within the lateral 1/3 of metaphysis) (moderate=Middle third) (Severe= Medial Third)

5.    On True lateral Xray, angle at which epiphysis makes with Metaphysis (Southwick head-shaft angle) (normal = 0 deg, mild=0-30 Deg,moderate30-60 deg, Severe=>60 deg)

6.    CT is useful for measuring degree of tilt. USG has not been usually advocated though can suggest with fluid presence. MRI  shows slip earliest. MRI also  helps in follow up  and also to keep a check on contralateral hip.