Rickets — the metaphysis at the fastest-growing physis

X-ray

First and second year — the floor first, then every step

Widened physes with frayed, cupped, splayed metaphyses at the wrist and knee, plus a rachitic rosary and bowing; healing shows as a dense zone of provisional calcification returning.

Orient first

  • Nutritional vitamin D deficiency is the commonest cause worldwide; renal and hypophosphataemic forms exist.
  • Changes are most visible where growth is fastest: distal radius and ulna, distal femur, proximal tibia, anterior rib ends.
  • Metaphyseal fractures in rickets are not the classic metaphyseal lesion of abuse, but both must be considered.

Acquire the study

  • PA radiograph of one wrist and AP of one knee; follow-up at 3 months to confirm healing.

The manoeuvre

  • Wrist PA: physeal widening in mm, metaphyseal fraying, cupping and splaying of the distal radius and ulna.
  • Knee AP: same metaphyseal changes at the distal femur and proximal tibia; bowing of the tibia.
  • Bone density: generalised osteopenia, thin cortices, coarse trabeculae.
  • Chest radiograph (if taken): widened anterior rib ends (rosary).
  • Follow-up: return of the zone of provisional calcification — a dense metaphyseal line.

What confirms it

  • Metaphyseal fraying and cupping with physeal widening, with biochemistry (vitamin D, calcium, phosphate, ALP).

What licenses you to exclude it

  • A sharp zone of provisional calcification at the wrist and knee excludes active rickets.

The classic misread

  • Calling normal metaphyseal cupping at the ulna in a toddler rickets — look for fraying and physeal widening.
  • Forgetting to look for fractures and Looser zones.

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