I have played tennis regularly for 25 years and am now 66. I have never had tennis elbow but I might now be suffering from tennis hip - if there is such a thing. I experience stabbing pains in the interior of my left hip when making rotational or unusual hip movements in play, though I am fine when rested. I am a right-handed player so my left hip bears my weight when I serve or play forehands. What is the problem and what can I do about it?
Kevin Smith, London

The hip, a ball-and-socket joint, is one of the largest joints in the body, and one of the most stable. Aside from osteoarthritis, hip problems can arise from muscle strains, a slipped disc and hip bursitis, which is the inflammation of the bursa (a sac containing fluid) on the outside of the hip joint itself.

Problems can also occur from tears of the labrum, a fibrous cartilage (similar to the meniscus in the knee) that adds stability to the hip joint and cushions it. A labral tear may be degenerative or traumatic. Degenerative tears occur after years of repeated minor injuries, and are usually associated with arthritis of the hip. Traumatic injuries are sustained during any sport that requires rapid hip motion with sudden stops and turns on the field. Sometimes an injury causing a labral tear is trivial, and long gone by the time of the diagnosis. From what you say, you may have a labral tear, but one cannot exclude osteoarthritis as the cause of your symptoms. The fact that there is no pain at rest is not, unfortunately, a sign that your hip joint is fine, as in the early stages of osteoarthritis pain may well be present only when the joint is stressed. Because there are many possible causes, I suggest that you see a sports or a musculo-skeletal physician to make sure of the diagnosis.

· Professor Maffulli is a consultant orthopaedic and sports injury surgeon at Keele University medical school. If you have a question for him, email fitness@theguardian.com