Casts and Their Problems

Plaster of Paris ( POP )

POP is cheap, easy to use and can be moulded. Usually applied in the form of a bandage or multiply folded as a supporting slab.Disadvantages are susceptibility to damage ( POP rapidly disintegrates if wet ) and that it takes up to 48hr for larger casts to dry fully after application . Cut slabs to shape prior to use and apply over wool roll and stockinette. Mould with palms (not fingertips) to avoid point indentation of plaster.

Resin casts

More costly, but lighter and stronger than POP and more resistant to water or other damage. Made of cotton or fiber glass impregnated with resin that hardens after contact with water. Sets in 5 10min, maximally strong after 30min. Resin casts are more difficult to apply and remove. Being more rigid and harder to mould, there is i risk of problems from swelling or pressure necrosis. Remove / cover any sharp edges on the cast.

Complications of casts

Give all patients discharged with casts clear written instructions (including contact phone number) to return if they develop pain or other symptoms in the immobilized limb. Formal cast checks within 24 hrs are only required if there is particular concern about swelling. Simple swelling or discoloration of fingers or toes usually responds to elevation and simple exercises.

Is the cast too tight?

Act immediately upon suspicion of circulatory compromise from a cast. Look for the five P's: pain , pallor, paraesthesia, paralysis, and ' perishing cold . If any of these are present:

• Elevate limb
• Cut wool and bandages of backslab until skin is visible along the whole length of limb
• Split full casts and cut through all layers until skin is visible along the whole length of limb
• Any undivided layers will continue to obstruct the circulation until released. If this action fails to completely relieve the symptoms, contact orthopaedic and vascular surgery staff immediately, as angiography and urgent surgical intervention may be required. Note that compartment syndrome may occur in the presence of normal pulses.

Is the cast too loose?

Test by trying to move the plaster longitudinally along the limb. Replace excessively loose or damaged casts, unless there is an outweighing risk of fracture slippage.

Local discomfort

If there is local pressure discomfort (e.g. over a malleolus), cut a window in the cast to allow direct inspection of the skin . Trim or replace plasters, which restrict movement unduly

Cost removal

Standard POP and selected resin casts may be removed with plaster shears. Use a plaster saw only after instruction in its proper use. In both as, be careful to avoid skin damage.