Common in dancers, and usually the musclesEmerging evidence
Dance asks the hip for extreme range under control: turnout in ballet, développés and grands battements, splits and straddles, deep pliés, and fast changes of direction in street and Latin styles. Across 13 studies of dancers with ballet training, 345 of 2,001 injuries (17.2%) were in the hip and groin, more in professionals than students, at 0.09 per 1,000 dance hours; the review adds that "The breakdown of specific injuries such as snapping hip, labral tears, and muscle strains was not possible in this study." An earlier review found "a high prevalence and incidence of lower extremity, hip and back injuries" in dancers, and in hip hop and street dancers the groin was the second commonest injury site after the knee.
A review of hip pain in ballet dancers names three common causes: a pinch inside the joint (impingement), an unstable, overly mobile hip, and snapping outside the joint. Most aches after a class are the muscles, the hip flexors at the front or the inner thigh muscles (the adductors), working harder or longer than usual, and the joint itself is the less common source; that is our reading, as no study counts them.
Sources 1, 2, 3, 4
A click or snap is usually harmlessEmerging evidence
In 87 elite ballet dancers, 91% reported a snapping hip, 58% had some pain with it, and only 7% had taken time off dance for it. In the hips the researchers scanned, ultrasound showed the hip flexor tendon (iliopsoas) snapping at the front in 59% and the band down the outside of the thigh in 4%, and in a third the scan couldn't show the cause. A painless click isn't a reason to stop; our snapping hip guide covers snapping that hurts.
Source 5
Very flexible hipsEmerging evidence
Very flexible (hypermobile) joints are common in dancers: in Royal Ballet School students and Royal Ballet dancers, hypermobility was far commoner than in people who don't dance (an odds ratio of 11). Yet in a professional company followed for 5 years, hypermobile dancers had no more hip pain or hip injury than other dancers, and none retired because of a hip injury. With pain, frequent sprains or joints that slip, the NHS says "The main treatment is improving muscle strength and fitness so your joints are better protected", and advises "do not overextend your joints just because you can".
Sources 6, 7, 8
Heels and the hipEmerging evidence
In 81 lab studies of women walking and standing in heels, heels had "a slight effect on hip kinematics, with biomechanical changes and adaptations concentrated in the knee and foot-ankle complex" (kinematics means how the joint moves). None of these studies was of dancing. So hip pain after dancing in heels is more likely to come from the dancing itself (the turns, kicks, hip action and hours) than from the heel: that is our reading, not something a study has tested.
Source 9
When it isn't dancing: the causes the warning signs cover
Some hip and groin pain has causes dancing didn't create, and the warning signs follow the pages behind them. Severe hip pain after a fall or injury, a leg you can't walk on or put weight on, or tingling or loss of feeling in the hip or leg after an injury needs a 999 call or A&E, the NHS broken hip page says; a broken hip is more common in older people. The NHS sciatica page asks for a 999 call for numbness around the genitals or bottom or new trouble peeing or pooing, and a hot, swollen hip with a high temperature can be a joint infection, which the NHS septic arthritis page says needs urgent treatment. A child's sudden hip, knee or thigh pain, or a leg they can't put weight on, needs A&E, and a limp needs a same-day check, as the NHS pages on hip pain in children and limping say.
A stress fracture of the neck of the thigh bone is rare, but a review of these fractures in sport says it should be considered in any athlete with hip pain that comes on with exercise, because a late diagnosis can let the bone shift. New hip pain with long-term high-dose steroids, heavy drinking, sickle cell disease or lupus can be avascular necrosis, a loss of blood supply to the ball of the hip, the subject of a clinical review in the BMJ. The NHS asks for a 999 call for a femoral hernia with very bad tummy pain or vomiting, and NHS 111 for a painful hernia; sudden, severe pain in a testicle is an emergency, the NHS testicle pain page says; and NHS inform asks you to contact your GP practice for a lump in the groin, which may be a hernia.
NHS inform also says new hip pain should often begin to settle within 6 weeks. Bone pain that is constant or worse at night needs checking, the NHS bone cancer page says, though that is rare. A complete tear of the adductor tendon is rare too; in 16 male athletes with one, exercise-based treatment was followed for a year. And more than one stress fracture, periods that stop, or eating too little for your training needs a GP: the International Olympic Committee calls this relative energy deficiency in sport (REDs), an Endocrine Society guideline covers periods that stop, and an NHS trust's leaflet covers caring for a stress fracture.
Sources 10, 8, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46
When a scan helps, and how it usually goesEmerging evidence
Most hip pain after dancing needs no scan, and scans of dancers' hips find a lot whatever the symptoms. In 49 professional ballet dancers and 49 sporting people, labral tears (tears in the rim of cartilage around the socket) were found in 51% of all hips, in both groups alike, and weren't linked with pain. In 20 professional female ballet dancers, MRI (magnetic resonance imaging) lesions "were the same for symptomatic and asymptomatic dancers", and in 30 professional ballet dancers the ball of the hip slid out of the socket by a mean 2.05 mm in the splits, while the typical bone shapes of impingement were rare.
So a scan matters when the hip catches, locks or gives way, when pain hasn't improved after a good 3 months of exercise-based treatment, or when a stress fracture or loss of blood supply is suspected; a teenager's suspected avulsion fracture, or a hip you can't stand on after a fall, needs an X-ray the same day. Ultrasound can show a snapping tendon moving, but it couldn't show the cause in a third of snapping hips in one study.
Muscle soreness settles within days, and most snapping hips never stop a dancer. Over 5 years in a professional ballet company, cartilage didn't get worse in 19 of 21 dancers: "Elite level ballet did not negatively affect cartilage health over 5 years." For the few who need keyhole surgery (hip arthroscopy) for impingement, 62 of 64 dancers in one series returned to dance, at an average of 6.9 months, and in another series of 63 competitive dancers, 63% returned to their previous level, 21% to limited dance and 16% didn't return. These are selected surgical series without comparison groups, and no one can promise a date.
Sources 11, 12, 13, 5, 14, 15, 16
