A fracture of the scaphoid usually results from a fall on an outstretched hand. The scaphoid is an unusual bone and fractures of the scaphoid can be a complex problem. The main reason behind the complexity is that the scaphoid receives its blood supply through a narrow area and a fracture through the middle of the bone can mean that one half of the bone is left without a blood supply. This increases the likelihood that the fracture will not heal, and also that one part of the bone will die (termed “avascular necrosis”). If the fracture doesn’t heal the wrist biomechanics are disrupted, leading to an unstable wrist with pain and severe arthritis at an early age.
It can be surprisingly difficult to diagnose a scaphoid fracture. Some patients do not realise that they have broken a bone in the wrist, and continue with their normal activities thinking that they have a sprained wrist. Sometimes the fracture does not show up on the initial X-rays. For this reason doctors are taught that if a patient has pain in the region of the scaphoid bone after a fall that the patient should have a splint or cast applied to hold the wrist and thumb still until a specialist review can be organised. In most instances a specialist can determine if the scaphoid is fractured by examining the patient and repeating the X-rays at 7-10 days after the initial injury, however sometimes special scans are required to confirm the diagnosis (such as a bone scan, CT scan or MRI).
Simple scaphoid fractures that are not displaced (that is, where the broken edges are sitting together with no gap between them) can be treated with a cast for 6-12 weeks. The cast is extremely important in preventing movement at the fracture site; movement will make it more likely that the fracture will not heal, so if your cast becomes loose between your appointments please ensure you make prompt arrangements for the cast to be re-fitted.
In rare cases the scaphoid fracture will fail to heal and then an operation will be recommended. Because scaphoid fractures are potentially problematic you will be followed up for 12 months with X-rays and/or CT scans to check that everything continues to progress satisfactorily.
Scaphoid fractures that are displaced (where the broken edges are separated apart) require an operation. Generally this involves placing a screw across the scaphoid. The screw is buried within the bone and compresses the two broken ends together. After the operation you will need to wear a splint for approximately 6 weeks, and perhaps longer if you have delayed healing. Your follow-up will continue for 12 months to check that everything is progressing satisfactorily.
The screw usually remains in position permanently and is not removed. Your surgeon may recommend that you have a wrist arthroscopy at the same time that the screw is put in position to confirm exact placement of the screw.
If you are a smoker it is strongly recommended that you quit smoking to improve the likelihood of successful healing.
Surgery for simple fractures
Well over 90% of simple fractures will heal if they are treated with a cast. However some patients with a simple fracture elect to have surgery to avoid the need to wear a cast for a prolonged period, and to potentially return sooner to normality. The surgery is technically complex, so please discuss the potential risks with your surgeon and be fully informed before proceeding with this option.
The location of the fracture is also a factor that can influence the decision for surgery. Fractures of the proximal pole of the scaphoid are less likely to heal than fractures of the distal pole, because the blood supply to the proximal pole is less reliable after a fracture. This can be a reason to consider early surgery if you have a proximal pole fracture.
This video describes the benefits and technique of percutaneous scaphoid fixation for scaphoid fractures.
The video below demonstrates one technique for placing a screw within the scaphoid. The technique shown differs slightly to the one that Dr Tomlinson uses, but the overall basis of placing a straight wire within the scaphoid, confirming the position on x-ray, then placing a screw over the top of the wire, is the technique used at Melbourne Hand Surgery.
Scaphoid non-union (failure to heal)
If patients do not realise that they have broken a bone in the wrist and continue with their normal activities it is unlikely that the scaphoid fracture will heal. Sometimes scaphoid fractures do not heal even if they are diagnosed early and the recommended cast is applied, or initial surgery is performed to place a screw across the fracture. If you have a scaphoid fracture that has not healed (this is termed “scaphoid non-union”) you will require surgery. The aim of early surgery is to restore the scaphoid bone, commonly with a bone graft and screw fixation. This surgery is successful in 50-75% of cases, but often requires splinting or casting for prolonged periods of time.
Remember that wearing a splint is not the end of the world - while there are restrictions placed on your activities you can still enjoy life with a splint. Very importantly, if you have a scaphoid fracture or a scaphoid non-union you should definitely not smoke. Smoking impairs the blood supply and will increase the likelihood of complications. If you are a smoker the best thing you can do to help your progress is to stop smoking. It's not easy to quit but there are many ways your doctor can help you.
If your scaphoid fracture was many years ago and you have collapse of the wrist bones with marked arthritis then the scaphoid bone will not be able to be restored, but a partial wrist fusion may provide good relief for your pain and wrist instability. The downside of a partial wrist fusion is a reduced range of movement of the wrist long term. The upside of a partial wrist fusion is that it can take you from having a painful and unstable wrist (with a hand you really can’t use) to having a stable wrist that you can use in your daily life without being limited by pain.
The partial wrist fusion that is most commonly done for a scaphoid non-union with severe arthritis is a four corner fusion. In some instances you may also benefit from having the nerves that carry pain sensation from the wrist removed during the operation (“ablation of the posterior and anterior interosseous nerves at the wrist”).
Potential complications of surgery include wound infection, wrist stiffness, scar tenderness, an unsightly scar, failure of the scaphoid bone to heal ("scaphoid non-union"), persistent pain (or failure of the operation to relieve pain), arthritis and complex regional pain syndrome. Your surgeon will discuss these with you prior to surgery.
Image credit: hand skeleton images created with DrawMD.