LOGIC March 2018 Vol 17 Vol 1 - Page 40

Cobra Cast Cobra Casts are frequently used for MC fractures and many casting departments use them to treat tendon injuries. Fingers should have padding wrapped between them prior to casting to prevent maceration and the hand must be in the POSI (Figure 1) to safely rest the soft tissues and facilitate faster rehabilitation after casting. Figure 3 shows a full Cobra Cast, which will require splitting for the first week to allow for swelling. The split would completed at 1 week with synthetic. The cast can stay insitu for the healing period or, providing it can be removed safely, i.e. retaining reduction of the fracture, be replaced with a synthetic cast once swelling is reduced. Complete casts are more sturdy and harder for patients to remove. They, therefore, maintain the reduction better. However, the cast often has to be changed at 1 week because they have become loose due to the reduction in swelling. (See Figure 7 for information on casting materials). Finger Splints Figure 3: Cobra Cast normally be along the dorsal surface but not over the fractured metacarpal. In some cases, a plaster slab in this position is used as an alternative. Complete or Full Casts If a full plaster cast is used the cast must be split to allow for swelling. The cast can then be March 2018 L.O.G.I.C Finger fractures may be treated with buddy strapping only, but some require splints to hold them out to length and stop displacement. These will normally be buddy strapped after their post reduction X- ray. Thumb Spica The most common thumb injuries are metacarpal fractures and Ulna Collateral Ligament (UCL) Injuries (Figure 4 & 5). X-ray should be taken before stressing the UCL because if there is an avulsion fracture stressing it can cause displacement. When testing the UCL the uninjured thumb should be assessed first for a comparison and the thumb should be stressed flexed to isolate the tendon. If there is significant laxity a thumb splint or cast will be needed for 3 weeks. If there is no end point, i.e. the joint keeps opening when stressed because there’s no tendon to hold it, referral to hand surgeon for further management is required. Thumb spicas go from the tip of thumb to wrist area the length will depend on the injury. They are two pieces of plaster slab placed in a T shape on the thumb, one length wise and one across it, then bandaged on. For a UCL, the thumb must not be not abducted (sticking out) as this further stresses the tendon. Scaphoid Fractures Although many casting departments include the thumb in a cast for a scaphoid fracture (Figure 6), the Bone Shop has found that this does not improve healing and leaving the thumb out enables more joint movement and less joint stiffness. Unless indicated by pain on thumb movement, a below elbow casts without the thumb included is used. Clinical scaphoid fractures with tenderness in the anatomical “snuff box” but no radiological changes will be treated either in 38