Hip dysplasia -- shallow or malformed acetabulum (hip socket) that provides insufficient coverage of the femoral head -- was once considered primarily a paediatric condition identified at birth. It is now understood as a common cause of hip pain and early osteoarthritis in young and middle-aged adults, particularly women. The dysmorphic anatomy concentrates hip joint loading onto a reduced contact area, causing cartilage damage and pain at ages when most people would not expect to have a hip problem.
How Dysplasia Affects Hip Loading and Pain
In a normal hip, the acetabulum covers approximately 170 degrees of the femoral head. In dysplasia, this coverage is reduced -- the Centre-Edge angle (a radiological measurement) is below 25 degrees in lateral dysplasia. The consequence:
- The normal hip distributes joint loading across a large contact area. The dysplastic hip concentrates it on a smaller area, generating much higher contact pressures per unit area of cartilage
- The labrum (fibrocartilaginous rim that extends the socket) is overloaded compensating for bony inadequacy, causing labral tears -- a common early presentation of dysplasia
- Cartilage damage and early osteoarthritis develop at ages 20-40 in untreated moderate-severe dysplasia
The hip joint normally bears 3-5 times body weight during walking. In dysplasia, this load is concentrated on a smaller cartilage surface -- the per-area pressure is substantially higher than in a normal hip of equivalent body weight.
Walking Cane Function in Hip Dysplasia
A walking cane reduces total hip joint loading by approximately 15-20% of body weight during ambulation. In the context of dysplasia, this load reduction reduces the contact pressure on the already over-stressed cartilage area. Over long walking distances, this can meaningfully reduce cumulative cartilage loading and associated pain.
The cane is typically held in the hand contralateral to the affected hip -- the standard cane-side rule -- to maximise the load reduction on the symptomatic side.
Who Needs a Cane in Hip Dysplasia
Not all dysplasia patients require a cane. Cane use is most appropriate for:
- Symptomatic dysplasia with pain during walking that is reducing walking distance
- Patients awaiting periacetabular osteotomy (PAO) or total hip replacement where the wait is long and pain is accumulating
- Post-PAO recovery (as for other hip surgeries -- see related articles)
- Moderate-severe dysplasia with early osteoarthritis where cartilage preservation is a treatment goal
Dysplasia vs. Impingement: Different Loading Profiles
| Condition | Anatomy | Loaded Position | Pain Pattern | Cane Benefit |
|---|---|---|---|---|
| Hip dysplasia | Shallow socket (undercoverage) | Weight bearing throughout | Lateral/anterior hip, worsens with distance | Load reduction throughout stance |
| Femoroacetabular impingement (FAI) | Excess bone (overcoverage or cam) | End-range flexion/rotation | Groin pain with specific movements | Limited -- movement-specific, not load-related |
| Labral tear (isolated) | Torn fibrocartilage rim | Weight bearing and rotation | Catching, clicking, groin pain | Modest load reduction during weight bearing |
Cane Height in Dysplasia
Standard cane height (wrist crease when arm hanging at side) applies. Patients who have developed an antalgic gait (leaning toward the affected hip to reduce loading -- the Trendelenburg gait) may unconsciously alter their standing posture. Height should be set in the normal standing posture, not the antalgic lean.
View the DaiWalk cane range and use the cane length calculator. Related reading: Walking Cane for Hip Labral Tear | Walking Cane for Hip Osteoarthritis
