Scaphoid is one of the 8 bones present in the wrist. The 8 small bones are aligned in 2 rows. scaphoid bone takes care of coordination of mobility between the two rows.
Scaphoid fracture may result from falling down onto the hand while the arm is wide open. This is the bone that is mostly exposed to fracture amongst the wrist bones. Scaphoid structuring and vascularity is quite interesting. It has a 3D variable form similar to beans. Circulation of the part that is proximate to the wrist is weak due to blood build-up of the bone and vascular structure. The vein structures that enable blood build-up following the fracture may be damaged, so circulation of part of the bone breaks down (avascular necrosis), resisting the joining.
Nonunion is a condition of lack of joining in 6 months after the fracture happens. Problems of nonunion that take more than usual is called delayed nonunion. Nonunion affects wrist functions, and the balance between the two rows composed of the wrist bones is interrupted. Two parts of the scaphoid act independently, which leads to wrist mechanical problems that increases arthritis in the wrist.
No-union is observed in cases that do not recover for a long time after being plastered or in the post-operative period. Some patients of scaphoid fracture may not be aware that fracture occurred and it did not union. The fracture is identified only when they apply to a physician for complaints of wrist pain. These patients have a wrist trauma history for part of their life as they have neglected it. Direct x-ray, computerized tomography and MRI are beneficial to diagnosis.
In the absence of a specific arthritis, objective of the treatment is to ensure joint union. Circulatory breakdown of fracture part of the bone towards the wrist that is called avascular necrosis is influential for making the treatment decision. In treatment, fractured fragment ends are refreshed by fixing them with screw or chords after putting a bone graft in between. In case of circulatory break down on the fractured part of the upper bone, vascular bone transplantation is performed, trying to union the fracture and feed the bone.
If arthritis has already started in the wrist, there is no need to put further efforts to union the scaphoid. The objective here is to resume the wrist in an indolent and functional manner. Depending on the degree of wrist arthritis, one should, first of all, decide which of the surrounding joints are to be protected. Radial stiloidectomy (removal of part of arthritic radius), proximal row carpectomy (removal of upper row of wrist), limited filling up of wrist and scaphoid sub-pol removal and total wrist filling up for very common arthritis are planned.
Source: scaphoid pseudarthrosis
