Recognizing posterior dislocation
On the second day, while being turned, the client feels sudden severe pain and a pop in the operated hip. These are classic signs of prosthetic hip dislocation. A posterior surgical approach weakens the back of the joint, so the femoral head usually dislocates posteriorly. A posterior hip dislocation presents with sudden pain, a pop, and a leg that is shortened and internally rotated. Turning is a high-risk moment because the operated leg can fall into adduction and internal rotation.
Why the leg looks shortened and turned inward
When the femoral head slips out behind the socket, the femur moves upward along the back of the pelvis, so the leg appears shortened. The position of the displaced head forces the thigh into adduction and internal rotation, so the knee and foot turn inward. The client usually cannot move the leg and pain is severe.
| Leg appearance | Usual cause |
|---|
| Shortened and internally rotated | Posterior hip dislocation (the risk after a posterior approach) |
| Shortened and externally rotated | Femoral neck or intertrochanteric fracture of a native hip |
| Lengthened or neutral length, externally rotated | Anterior hip dislocation |
| Lengthened and internally rotated | Does not match a common hip injury pattern |
Watch out! The picture of a shortened, externally rotated leg is so familiar from hip fracture questions that it is easy to choose by reflex. That pattern belongs to a fracture of the native femoral neck. After a posterior-approach replacement, the dislocation pattern is internal rotation.
Nursing action
The nurse keeps the client still, does not attempt to reposition or pull the leg, checks neurovascular status of the foot, and notifies the surgeon at once. Reduction is done by the medical team, often under sedation, and imaging confirms the position. Afterward the nurse reinforces hip precautions and safe turning technique with the abduction pillow. Key point! Posterior dislocation after hip replacement shortens the leg and rotates it internally; keep the leg still and notify the surgeon.