GTPS stands for greater trochanteric pain syndrome. The greater trochanter is a bony prominence at the top of the femur (thigh bone). Pressure alongside the hip over this point causes tenderness or pain for people with GTPS.
Not all patients with this problem are women. About nine per cent of the general adult male population report symptoms of GTPS. But since 24 per cent of women in the same age group have GTPS, it's clear that women are affected more often.
Doctors aren't sure what causes GTPS. There have been many suggestions over the years and studies to find out. Some suggest the flared pelvic rim in women alters the pull of muscles and connective tissue causing the problem. Others suggest that hormonal factors affecting pain generators in the bursa is the source of the problem.
Obesity, knee arthritis, and low back pain are common among people with GTPS but which came first (the GTPS or the other problems) is also unknown. Since the back, hip, and soft tissues are all connected, there's some thought that a problem in one area leads to problems in the other areas.
Some people have GTPS on both sides (bilateral), others only have one hip affected (unilateral). More study is needed to find out what causative and risk factors might be present and how it's different for people with unilateral versus bilateral symptoms.