This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pelvis & Injuries, Subject name: Orthopaedics
Telescopic test is useful to diagnosis: 
Select and explain. 
A. Perthe's disease, B. Intracapsular fracture neck of femur, C. Malunited Trochanteric fracture, D. Ankylosis of hip joint
B: Intracapsular fracture neck of femur
Answer: B: Intracapsular fracture neck of femur 
Explanation: (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.