<prompt> Telescopic test is useful to diagnosis:Perthes diseaseIntracapsular fracture neck of femurMalunited Trochanteric fractureAnkylosis of hip joint  <response>: b Intracapsular fracture neck of femur- Positive Telescopy test indicates instability of hip joint such as: old unreduced posterior dislocation, loss of neck and or head in old fractures neck femur and paralytic hip. 