Usually the gluteal tendons, not just a bursaStrong evidence
Outer hip pain is most commonly greater trochanteric pain syndrome, which takes in tendinopathy or tears of the gluteus medius tendon, bursitis and friction from the iliotibial (IT) band, a 2021 clinical review says, and gluteus medius tendinopathy or tears are now thought to be more common than bursitis. NHS inform describes it as irritation of the tendons and the bursa (a small fluid-filled sac) over the outside of the hip bone.
On ultrasound in 877 people with this pain, 177 (about 1 in 5) had bursitis, while about half had gluteal tendon changes and 28.5% a thickened IT band. On magnetic resonance imaging (MRI) in 24 women, 11 had a gluteus medius tear and only 2 a swollen bursa, never without tendon changes. A review explains why position matters: the tendons are thought to suffer most when they're squeezed against the bone as the thigh drifts across the body and are loaded at the same time.
Sources 1, 2, 3, 4, 5
Who gets it, and what brings it onEmerging evidence
In an American population study of 3,026 adults aged 50 to 79, it affected 15% of women and 6.6% of men on one side, and 8.5% and 1.9% on both; women had about 3.4 times the odds. Tenderness over the IT band, knee arthritis on the same side and low back pain went with it; body mass index didn't, once those were allowed for. NHS inform says it is more common in women and between 40 and 60.
NHS inform lists pain in the hip, thigh or buttock, worse lying on that side or with direct pressure, with walking, standing or running, sitting with your legs crossed, standing on that leg ("hanging on the hip"), climbing stairs, and lifting your legs in or out of a car or bed. A sudden rise in walking, a fall onto the side of the hip, weakness, hormone changes, arthritis in the hip or knee and low back pain can all contribute.
Sources 6, 2
What clinicians checkEmerging evidence
In 65 people with outer hip pain, pain within 30 seconds of standing on the painful leg made tendon changes on MRI very likely, and no tenderness over the bony point made them unlikely; but 31% had tendon changes on MRI without positive tests. Across 6 studies of 272 people, pressing on the tendons and then testing the hip pushing outwards against resistance moved the chance of the diagnosis from 59% to 96% when both hurt, and to 14% when neither did; the certainty was very low to moderate.
In 24 women, the pelvis dropping on the other side when standing on the painful leg (a positive Trendelenburg sign) was the best clue to a tear. The 2021 review says that if the pain doesn't improve with physiotherapy and anti-inflammatories, a tear should be considered.
Sources 7, 8, 4, 1
Other causes felt on the side of the hipEmerging evidence
The commonest snapping hip is on the outside, where the IT band flicks over the bony point; it is usually painless. A burning, tingling or numb patch on the outer thigh, sometimes down to the outer knee, is meralgia paraesthetica, a squeezed skin nerve; tight clothing, a heavy tool belt and weight gain are common causes, the American Academy of Orthopaedic Surgeons (AAOS) says.
Pain from the hip joint itself is mostly felt elsewhere: in 51 people whose hip joint was confirmed as the source by an injection, it was felt in the buttock in 71%, the thigh in 57% and the groin in 55%, and never in the lower back. Pain from the back can be felt at the outer hip, and the two are easily mixed up: in one spine centre, outer hip tendon pain turned out to be the cause for a sizeable share of the people referred with low back pain. A stress fracture of the top of the thigh bone in a runner usually causes groin pain, so it is a warning sign rather than outer hip pain.
Sources 9, 10, 11, 12, 13
When a scan helpsEmerging evidence
A scan isn't needed to start treatment for the typical pattern. If it isn't improving with physiotherapy and anti-inflammatories, an ultrasound or MRI can look for a gluteus medius tear, the 2021 review says; MRI is also how the main trial confirmed the diagnosis. Standing X-rays of the hip and pelvis are the first test for long-lasting hip pain that isn't clear, mainly to look at the joint, and the National Institute for Health and Care Excellence (NICE) diagnoses hip osteoarthritis without imaging from 45 when the pattern fits. A runner's groin pain that builds with every step needs urgent imaging.
Sources 1, 14, 15, 13
How it usually goesEmerging evidence
It is often slow. NHS inform says it can take 6 to 12 months of rehabilitation to settle, and flare-ups along the way are normal. In Dutch general practice, at least 36% of 164 people still had pain after a year and 29% after 5 years, and arthritis in the legs raised the chance of it lasting.
It often improves anyway: in the main trial, 20 of 68 people who waited and saw reported success at 8 weeks and 31 of 60 at a year, and in another trial 34% had recovered by 3 months and 60% by a year with usual care. No one can promise a date.
Sources 2, 16, 15, 17