Our grandson has a slipped hip. He had surgery to put a pin through the cap of the bone to hold everything together as he grows. We are wondering how they will get that pin back out once the bone grows around it.

From your description, it sounds like you may be referring to a problem called slipped capital femoral epiphysis (SCFE). In this condition, the growth center of the hip (the capital femoral epiphysis) actually slips backwards on the top of the femur (the thighbone).

Surgery is usually necessary to stop the epiphysis from slipping further. A large screw is placed into the epiphysis to hold it in place. Most of the time, implants are left in and removal is not an issue.

The surgeon will take X-rays during the follow up visits to make sure that the screw remains in the right place. The X-rays are also required to determine when the epiphyseal plate fuses. At that point, there won’t be any chance that the slip will get worse. When this is known, the follow up visits will be focused on whether the abnormality is likely to need any additional surgery to realign the hip.

Opinions differ on the need to remove the screw once the epiphysis has fused. Removing the screw requires a second surgery that can be expensive and carries a slight risk due to the need for anesthesia.

Removing the screw takes twice as long as putting it in. There is a risk of breaking or stripping the screw during the attempted removal. Titanium screws seem to have the worst results. The hole left when the screw is removed also increases the risk of fracture after the screw is taken out. Many surgeons feel that the screw should be left in place if it isn’t causing problems.