Now we know that GTPS is a broad term encompassing soft tissues around greater trochanter (remember that bony part on the side of your hip), primarily affecting tendons and in some cases bursae too, which can be very irritable. We also know how it presents, so let's talk about prevalence, and some risk factors today.
Prevalence:
It rarely affects men, but can affect up to 23% of middle-aged and post-menopausal women, which could also be linked to hormonal changes. Estrogen plays a role in collagen production, which is essential for maintaining tendon tensile strength. When estrogen levels drop, it can lead to a decline in tendon health & function.
Common in less active individuals but also in athletes involved in long-distance running
Risk Factors:
Mechanical Factors: Overuse (doing more than your tissues can currently handle and tolerate), sudden increase in activity like running, high intensity training & not allowing your body to recover properly
Joint Position and Bony Morphology: Compression and tension are in general factors contributing to development of an insertional tendinopathy (such as gluteal tendinopathy in this case). Coxa vara (picture below- decreased angle of inclination) and a greater trochanteric offset (GT positioned more laterally/outward) can increase compressive forces on the surrounding structures. While some studies support this association, it is important to say that this is not always the case. Like other risk factors, these anatomical variations do not consistently lead to increased tendon pathology and should be considered alongside other contributing factors.
PMID: 38601140
Metabolic and Medication-Related Factors
Conditions like diabetes, hypercholesterolemia and genetic predispositions may increase risk (though most studies focus on other tendons in terms of genetics). Certain medications, including fluoroquinolones, statins, glucocorticoids etc., may cause changes in tendons. Therefore, it's always a good idea to check the medications you're currently taking and see if they could be related to your symptoms.
Muscle weakness and altered movement mechanics
Whether it is a chicken or egg scenario, hip abduction muscle weakness, along with gluteal atrophy and fatty infiltration have been shown in GTPS patients. We also have studies that show kinetic & kinematic changes in movement patterns when viewed from the front during walking and standing. For example, people with GT experience a greater external hip adduction moment during the stance phase of walking. This means that external forces push the hip inward (adduction), making the muscles on the outer part of the hip to work harder to counteract this force (higher internal stress on abductors).
The main factors influencing these forces were shown to be alterations in pelvic drop and trunk lean, which could stem from muscle weakness, atrophy, compensations etc., or it could simply be a pain response, meaning it's difficult to say if these patterns were a cause or effect of GTPS. For example, my previous patient with GTPS did not actually have any of these compensatory movements (maybe if she'd been in pain for a longer duration, she might have developed these as a result of higher pain levels and avoidance strategies). She only had abductor weakness during testing (again, probably just a consequence of painful hip), tight posterior hip capsule, limited hip IR and actually weak hip flexors on the affected side! And so the core issue seemed to be that during the summer, she was doing excessive work around the house- moving, cleaning etc. putting her into positions where she did not expose herself before a lot. So of course, we focused on strengthening her hip abductors through painless exercises, hinging movements and hip flexors work to get the loading in. However, I was not correcting her gait, nor did I blame the issue on just weakness etc.
In the next section, we will take a closer look at some diagnoses that can coexist with GTPS or mask its symptoms, as well as the importance of objective testing and imaging.
Appendix
Below are a few studies observing altered mechanics and muscles
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