What is Scaphoid Nonunion?
The scaphoid bone is one of the eight small bones that make up the wrist joint. Two rows of small wrist bones work together for various wrist positions and movements we naturally perform. The scaphoid bone connects these two rows and therefore has a special role in maintaining the stability of the wrist and coordinating wrist movements.
Because of its location in the wrist and its role in wrist function, the scaphoid bone is vulnerable to fracture. When the scaphoid bone is fractured, it may not heal properly due to its delicate blood supply. Unhealed scaphoid fractures are referred to as scaphoid nonunions. Ultimately, scaphoid nonunions can lead to loss of wrist movement and eventual arthritis in the wrist joint.
What are the Symptoms of Scaphoid Nonunion?
There is persistent wrist pain and limited wrist movements. When a scaphoid fracture does not heal, over time it can cause damage to the joint cartilage in the surrounding joints and the wrist joint. In most cases, the scaphoid bone collapses, causing a shortening of the bone. This results in loss of wrist mechanics and damage to the wrist cartilage.
How is Scaphoid Nonunion Diagnosed?
Patients with scaphoid nonunion usually have a history of wrist injury. When the details of the injury are questioned, there is a history of falling on an outstretched hand. They experience pain on the thumb side of the wrist and wrist mobility, especially movement of the wrist towards the back of the hand (wrist extension), decreases.
Scaphoid fractures and nonunion scaphoid fractures are usually confirmed by x-rays of the wrist. In most cases, special x-ray imaging, computed tomography (CT), and MRI imaging to understand the liveliness and blood supply of the broken parts are necessary to make a good treatment approach.
How is Scaphoid Nonunion Treated?
There are 3 different scenarios for the treatment of scaphoid nonunion. The type of surgery depends on these scenarios.
Treatment of nonunion scaphoid fractures is done surgically. If the joint cartilage is not damaged and one of the parts has not lost its blood supply as seen in the MRI imaging, the fracture is detected using a closed surgery technique and a screw.
If MR imaging shows that the blood supply to one or both of the scaphoid fracture fragments has been impaired, that is, if avascular necrosis has developed, then open surgery is required. In open surgery, the bone parts with impaired blood supply are removed and a piece of the patient's own bone (iliac bone) is placed in the empty space and the fracture is fixed with a screw.
If there is joint cartilage damage in the joints made by the scaphoid bone and the wrist joints, the surgery changes completely. In these cases, the surgery is aimed at improving pain as well as maintaining functional wrist. Depending on the degree of joint cartilage damage, techniques that preserve movement such as radial styloidectomy (removal of a local arthritic bone fragment), partial fusion of the wrist bones, or proximal row carpectomy (removal of the proximal row of wrist bones) may be included. If joint calcification is more widespread in the wrist, full wrist fusion may be necessary.
