THREE POINT MOULDING: FIBREGLASS CASTS COMPARED WITH PLASTER CASTS

Abstract

BACKGROUND: One of the prime concerns when managing patients in plaster casts is loss of reduction. There have been studies showing that proper moulding of plaster cast is critical in maintaining reduction. Recent studies have negated concerns that fibreglass (FG) casts do not allow swelling, when compared to plaster of Paris (POP) casts. However, their potential in maintenance of reduction has not been investigated.

MATERIALS AND METHODS: We compared the three-point bending properties of FG casts with POP casts over the first 48 hours. The effect of splitting the casts, at one hour and 24 hours, was studied. Also, the tolerance to handling was assessed by moving the hinge joint while the casts were setting.

Three identical jigs with hinged metal rods were designed to simulate Colle’s fracture. The bending force was provided by 0.5 kg weight applied at one end of the jig. The resultant displacement was measured to nearest 0.01 mm over the next 48 hours. Each test was repeated 6 times (total 8 groups and 42 tests).

RESULTS: Most deformation occurred within 1 hour for FG casts and 24 hours for POP casts. The total deformation in FG cast (mean 3.4 mm) was significantly less than in POP casts (mean 6.2 mm) (p > 0.05).

Splitting at 1 hour increased the final deformation of the POP cast and not of the FG cast (p > 0.05). No significant difference was noticed if the casts were split at 24 hours.

CONCLUSION: Three-point moulding with FG casts can provide better constant loading at the fracture site than the POP casts. Early setting of FG cast allows earlier splitting. We recommend clinical trials to ascertain the safety and efficacy of split FG casts.