Dwarfism is where an individual is short in stature as a result of slow growth and is defined when an adult height of less than 4ft 10in. There are two main types of dwarfism: Harmonious and Disharmonious dwarfism.

HARMONIOUS DWARFISM

Harmonious dwarfism is where both limbs and body are reduced in size, but the ratio of the limb to height remains proportionate.  With this form of dwarfism, the bone deformity can cause hyper-anteversion around the hips, typically with a 40° varus (inward) and a flexum of 40°. For limb lengthening, a 3-D correction must be performed to treat any hyper-anteversion before surgery.

DYSHARMONIOUS DWARFISM

Patient who gained an additional 16-cm to both femora with the Albizzia® nail after a 10-cm gain on both tibiae with an external fixator.

Patient who gained an additional 16-cm to both femora with the Albizzia® nail.

In disharmonious dwarfism, limbs are disproportionately shorter than the body. This is attributed to a disorder in bone growth, often genetically linked to chromosomes and affects conditions such as achondroplasia, hypochondroplasia and dyschondroplasia.

Treatment for this type of dwarfism consists of correcting any problems with joints and then lengthening the limb bones according to an individual’s needs.

 

JOINT CORRECTIONS

Achondroplastic patient who gained a further 13-cm on both femora with the Albizzia® nail after a 12-cm bilateral tibial gain.

This Achondroplastic patient who gained a further 13-cm on both femora with the Albizzia® nail.

For correcting joints in dwarfism deformities, hips present the greatest problem because the condition often includes a decreased femoral head by the pelvic acetabulum. If the socket is too small, the ball at the head of the femur may pop out during lengthening. For cases like this, an earlier operation to increase the size of the socket is required.

 

BONE LENGTHENING

Lengthening for dwarfism is generally performed with an intramedullary nail or external fixator.

Achondroplastic patient for whom 6 external fixators were used for lengthening (2 femora, 2 tibiae, 2 humeri). He agreed to a further 10-cm bilateral femoral lengthening with the Albizzia® nail and is willing to continue with further bilateral humeral lengthening with the Albizzia® nail.

Achondroplastic patient where 6 external fixators were used for lengthening (2 femora, 2 tibiae, 2 humeri). Further femoral lengthening with the Albizzia® nail should increase length to 10cm.