Table 3 The WHO principles of early disease detection applied to both developmental dysplasia of the hip (DDH) and paediatric flat foot posture

· The condition should be an important health problem.

Uncorrected DDH results in long-term pain, gait dysfunction and early arthritis

Indefinite prognosis for flexible flat feet, but rigid flat feet usually require treatment [48]

· There should be a recognisable latent or early symptomatic stage

Mostly detectable and reversible from birth

Most flat feet are asymptomatic in the first decade of life

· The natural history of the condition, including development from latent to declared disease should be adequately understood.

Some DDH normalizes in the first few months of life; controversy about when to treat, how long to monitor in cases of instability [49]. Recognisable risk factors in newborns are: breech birth, female, left hip affected, first born, family history of DDH [50].

A flat foot posture is expected in infants, and normally reduces with age. Recognisable associations with non-resolving flat feet may include: male, overweight or obesity, hypermobility, wider conditions e.g. Down’s, family history, increased shoe use from young age.

· There should be a suitable test or examination.

Clinical examination and ultrasound have demonstrated 97% sensitivity [51].

FPI-6 ≥ +6 indicates suitability of the p-FFP tool for diagnosis and directs management.

· The test should be acceptable to the population.

Clinical examination and ultrasound (and later x-rays) are acceptable tests.

No universally accepted definition for flat foot. [40].

· There should be an accepted treatment for patients with recognised disease.

Abduction splinting found to be safe and effective [52].

In the absence of symptoms, the indication for treatment is uncertain and should only be used when clinically definable outcomes can be improved.

· There should be an agreed policy on whom to treat as patients.

It is agreed that DDH be treated early to reduce the chance of serious pathology. There is some controversy regarding the age to commence treatment, given that some cases resolve.

The best available evidence supports treating rigid or symptomatic flexible flatfeet [48]. There is no clear evidence to support the treatment of most asymptomatic cases, especially in younger children [25]

· Facilities for diagnosis and treatment should be available.

Clinical examination and ultrasound are readily available.

Observation, the FPI-6 and the p-FFP are readily and freely available measures.

· The cost of case-findings (including diagnosis and treatment of patients diagnosed) should be economically balanced in relation to possible expenditure on medical care as a whole.

Late diagnosis increases worse outcome and increased need for surgery [46]

Not supported

· Case-findings should be a continuing process and not a ‘once and for all’ project.

Routinely occurs from birth and early paediatric health checks.

Not indicated