Hip Prosthesis: Could I cough it loose?

I had a hip replacement six years ago, and it's brilliant. However, I get a lot of chest infections, and when I cough vigorously, my hip prosthesis hurts. It never hurts at any other time, and I'm afraid that I might cough it loose, so I lie on my side to restrict it from - as I imagine - ricocheting around. Is it actually possible to cough a prosthesis loose, and should I be careful?

Dr Fred Kavalier answers your health question:

Many tens of thousands of hips have been replaced since the operation was introduced nearly 50 years ago. If the operation goes well, and there are no immediate postoperative complications, a new hip usually revolutionises a patient's life. People who were crippled with arthritic pain can walk again without any pain at all.

The hip joint is a ball-and-socket joint, and one possible complication is dislocation, when the ball slips out of the socket. This is most likely to occur soon after the operation. Now that you have had your hip for six years, it is very unlikely to dislocate. When you cough vigorously, the muscles of your abdomen contract. This muscular contraction pulls on your pelvis, and I suspect that this is the source of your hip pain. There is a possibility that your cough pain is the first sign that the new hip joint is beginning to loosen. New hip joints do sometimes work themselves loose, but if this happens it will not be because you are coughing too much.

If you are not getting any pain during ordinary activities, such as walking and climbing stairs, I don't think there is any need for you to worry - your hip prosthesis will definitely not be "ricocheting" around.

Please mail your questions for Dr Fred to health@independent.co.uk. He regrets that he is unable to respond personally to questions.