Loss of Position
Because swelling occur with most fractures especially after reduction, the technician puts padding under the cast to protect the skin. This padding gets compressed. After 48 hours when the oedema is subsiding, the cast may be too loose to hold the bone ends in position against undesirable muscle action.
Such displacement may be sudden and cause pain or gradual being first noticed on the next x-ray. This complication may seriously delay sound healing and may produce permanent deformity. Medical advice must be sought if the position is suspect.
Loss of power, tingling and numbness distal to the cast are signs of impaired nerve function. The cause may be direct compression by bone ends or plaster pressure, indirect compression of oedematous tissue or tourniquet effect, or reduced blood flow.
Routine testing of power and sensation will detect any defect quickly. Corrective action includes relieving cast pressure, supporting and protecting paralyzed parts, and physiotherapy to help restore normal function of muscle and joints.
Encasement of the limb or trunk in plaster may produce stiff joints, muscle wasting and impaired circulation. Physiotherapy and good nursing can help reduce these complications and speed the final recovery.
The most serious is deep venous thrombosis leading to pulmonary embolism. Pain in the calf is an important sign needing medical advice.
Immobilisation in trunk plasters or plaster beds may also produce nausea, abdominal muscle cramps, retention of urine and abdominal distention.
Good nursing and diet with regular exercises will help ensure that the initial period of extensive immobilization is achieved without complications.