What is a slipped upper femoral epiphysis?
At the top of the thigh bone there is a growth plate sitting just beneath the ball of the hip joint. In a growing child that plate is cartilage that has not yet converted to solid bone. A slipped upper femoral epiphysis - SUFE, also called SCFE in North America, is when the ball slips backwards and downwards relative to the neck of the thigh bone through that growth plate.
It is not a muscle strain, it is not apophysitis, and it does not settle with a fortnight off. It is a structural change in the hip joint, and the position of the ball will not correct itself. That is what separates it from almost everything else on this site.
It is uncommon, roughly one in several thousand adolescents - but it is the most common hip disorder of adolescence, and the consequences of missing it are significant enough that it deserves to be in every parent's and coach's mental checklist.
Why does it happen during adolescence?
In most cases there is no single incident. The slip is gradual, which is precisely why families describe weeks or months of vague ache before anything looks dramatic. In a minority it happens suddenly, often during sport, and the child cannot weight-bear at all.
- The growth plate is at its widest and mechanically weakest during the peak of the growth spurt.
- Body weight above the healthy range increases shear force across the plate; it is the strongest single risk factor.
- Rapid recent growth, particularly in taller children, adds leverage through the hip.
- Hormonal and metabolic conditions - thyroid problems, growth hormone treatment, kidney disease, raise the risk.
- Boys are affected more often than girls, and it is more common between roughly 10 and 16 years.
Why does it show up as knee pain?
This is the part worth remembering. The nerve supply to the hip joint shares segments with the nerve supply to the thigh and knee, so hip pathology in a child frequently refers pain down to the inner thigh or knee. Studies of delayed diagnosis consistently find that children who presented with knee or thigh pain waited far longer for the correct diagnosis than those who complained of the hip.
The practical rule is simple and worth applying without exception: in any child between about 9 and 16 with knee or thigh pain, examine the hip. If the knee looks entirely normal - no swelling, no local tenderness, full movement - and the pain is a vague ache rather than pinpoint, the hip becomes the priority rather than an afterthought.
What are the warning signs?
None of these signs behave like the growth-plate conditions parents read about most often. Osgood-Schlatter and Sever's hurt in a specific spot, flare with impact and settle with relative rest. A suspected SUFE hurts vaguely, changes how the child walks, and does not follow the usual settling pattern.
- A limp that persists for more than a week or two, particularly with no clear injury.
- The affected leg tending to turn outwards when walking or standing.
- Pain in the groin, front of the thigh or knee that is a dull ache rather than a sharp, pinpoint pain.
- Reduced ability to turn the hip inwards, often the earliest objective sign a clinician will find.
- Pain that has been grumbling for weeks and is gradually worsening rather than settling.
- Sudden inability to put weight through the leg, with the hip held slightly turned out, an emergency.
What happens if it is suspected?
Suspected SUFE is referred for same-day assessment and imaging, usually X-rays of both hips taken from two angles. Both sides are imaged because a proportion of children slip on the other side later, and some have a slip on both sides at presentation without symptoms on the second one.
If confirmed, the child is usually kept non-weight-bearing and treated surgically, most commonly by placing a single screw across the growth plate to stabilise the ball in its current position and prevent further slip. It is a well-established procedure with generally good outcomes when the slip is mild and caught early.
This is the one situation in youth musculoskeletal care where physiotherapy comes after the surgical decision, not before it. Rehabilitation matters enormously afterwards - restoring hip strength, walking pattern and confidence takes months, but no amount of exercise prescription substitutes for stabilising the joint.
What this means for parents and coaches
Almost every ache a young athlete brings home is load-related and will respond well to sensible loading, strength work and patience. SUFE is a reminder that a small number will not, and that a limp is never something to watch for a month.
The threshold to act is low and the question to ask is straightforward: is the child limping, and is the leg turning out? If yes, or if knee pain has no local findings at the knee, the hip needs to be looked at that day. Getting this checked and being told it is nothing costs an afternoon. Missing it costs a hip.