These two terms turn up on X-ray reports and cause more worry than they usually deserve. Both describe the same measurement, just in opposite directions.
The angle in question
The top of your thigh bone is not straight. It has a neck that angles inward and upward before the ball sits into the hip socket. The angle between that neck and the shaft of the bone is the neck shaft angle.
In adults it typically sits around 125 to 135 degrees.
- Coxa vara means the angle is smaller than normal, roughly below 120 degrees. The neck is more horizontal, so the leg sits closer to the midline.
- Coxa valga means the angle is larger, roughly above 135 degrees. The neck is more vertical.
Children are born with a much larger angle, around 150 degrees, which reduces naturally as they start walking and loading the hip. So a wider angle in a young child is often just normal development.
What each one does mechanically
| Coxa vara | Coxa valga | |
|---|---|---|
| Angle | Below about 120 degrees | Above about 135 degrees |
| Leg length | Slightly shorter on that side | Slightly longer |
| Abductor muscles | Longer lever, mechanically efficient, but muscles slackened | Shorter lever, muscles work harder |
| Typical consequence | Shear stress through the femoral neck | Load pushed onto the joint surface, less hip stability |
| Sometimes linked with | Stress injury, Trendelenburg gait | Hip dysplasia, higher dislocation risk in some conditions |
The practical version: coxa vara stresses the bone of the neck, while coxa valga stresses the joint surface and reduces stability.
Where they come from
Most of the time this is simply how you are built, with no cause and no consequence.
When there is a cause, the common ones are:
- Developmental, present from birth or emerging as a child grows
- Following a fracture of the femoral neck that healed at an altered angle
- Slipped capital femoral epiphysis, a growth plate problem in adolescence
- Conditions affecting bone quality, such as rickets or osteogenesis imperfecta
- Neurological conditions such as cerebral palsy, where altered muscle pull through growth changes the angle, most often producing coxa valga
When it actually matters
Here is the part worth holding on to: an angle outside the average range is not in itself a diagnosis. Radiology reports describe anatomy. Whether that anatomy is causing a problem is a separate clinical question.
It becomes clinically relevant when it comes with symptoms or signs such as:
- A limp, particularly the pelvis dropping on the opposite side when standing on the affected leg, known as a Trendelenburg sign
- A genuine, measurable leg length difference producing symptoms
- Hip or groin pain that limits activity
- In children, reduced hip movement, especially rotating the leg inward
- Repeated hip or knee problems on the same side
- Evidence of hip dysplasia alongside the angle
Without any of those, the finding is usually just a description of your skeleton.
Being told your hip angle is unusual is not the same as being told your hip is damaged. Most people with a measurement outside the average range walk, work and exercise entirely normally for life.
What treatment looks like
Most cases need nothing.
Where there are symptoms, conservative management comes first and is what physiotherapy addresses:
- Abductor strengthening, particularly gluteus medius, which is working at a mechanical disadvantage in coxa valga and slackened in coxa vara
- Gait retraining if there is a visible limp or pelvic drop
- Load management, adjusting how much and how quickly you increase activity
- A heel raise only where a leg length difference is genuinely producing symptoms, not simply because one was measured
Surgery, usually a corrective osteotomy that changes the angle, is reserved for significant deformity with real functional consequences, progressive cases in children, or when the hip is unstable. It is uncommon.
In children
Paediatric assessment is warranted for a persistent limp, pain in the hip, groin or knee, noticeably restricted hip rotation, or a leg length difference that is increasing.
Knee pain in a child deserves particular attention, because hip conditions very commonly refer pain to the knee, and the hip is easy to overlook when the complaint points elsewhere.
Get it assessed if
You have hip or groin pain limiting what you can do, a limp you cannot explain, a leg length difference causing symptoms, or a child with hip pain or a persistent limp.
If the only thing you have is a line on a radiology report and no symptoms at all, that generally needs no action beyond understanding what it means.