What are scaphoid fractures?
Scaphoid fractures comprise 2,5% of wrist fractures and up to 60% of carpal (the eight small bones in wrist) fractures. The scaphoid links the base of the thumb to the wrist, and scaphoid fractures are commonly seen in the younger sport playing population who fall on an outstretched wrist, putting their hand out and hitting the ground on the thenar (thumb) side of the palm. This is commonly seen in cyclists, skateboarders and athletes who fall on hard surfaces.
What are the related symptoms of scaphoid fractures?
Signs and symptoms of scaphoid fractures include pain that is typically at the base of the thumb on the palm as well as the backside of the wrist. There is swelling of the joint due to bleeding inside the joint. All wrist movements are painful, and weight-bearing on the wrist is very tender.
The scaphoid is the most problematic bone in the body with regards to its ability to heal. There are more papers written on the union process of the scaphoid than any other bone in the body. This is because the blood supply to the scaphoid arises from distal to proximal (reversed from conventional anatomy), the scaphoid is completely covered with cartilage, and the fact that the scaphoid moves with every inch of wrist movement, balancing complex torsional forces.
The scaphoid is boat-shaped, and most scaphoid fractures (65%) go through the waist of the scaphoid, i.e. through the middle of the bone. The more proximal (closer to wrist) the fracture, the greater the chance that the blood supply is cut off (avascular necrosis) and the fracture does not heal (non-union). There is a 10-16% risk that the fracture does not unite (heal) despite a cast immobilisation.
To diagnose scaphoid fractures, Dr van der Spuy usually uses plain X-rays with clinical stigmata. Some patients present with a clinical picture that is very suggestive of a scaphoid fracture but X-rays are normal. In this group, the hand surgeon will use an MRI scan to diagnose a hidden (occult) fracture, with bone swelling seen on T2 sequence. CT scans are useful to show displacement and deformity, especially in a chronic setting.
How are scaphoid fractures treated?
To treat undisplaced scaphoid fractures, Dr van der Spuy may apply a cast to immobilize the hand for 8-12 weeks. Recent data suggests that even undisplaced fractures can be unstable and there is a tendency to operate (putting a compression screw across the fracture) on these cases early, particularly in the active sportsman. Hand surgery may be recommended, as early as possible, to treat fractures that are displaced more than 1mm. The hand surgeon may treat a scaphoid non-union with bone grafting and screw fixation.