Scaphoid Fractures and Non-unions
A fall on an outstretched hand commonly breaks the scaphoid bone of the wrist. If the fracture is not recognized early, it may not heal properly (non-union) and lead to delayed treatment and long term problems.
The wrist is made up of eight separate small bones, called the carpal bones. The scaphoid bone is located on the thumb side (radial side) of the wrist (Picture 1). It is the most commonly fractured carpal bone, probably because it crosses two rows of wrist bones. Scaphoid gets jammed against the forearm bone and strong wrist ligaments when we land on outstretched hand trying to protect the body during fall. This stress can cause either a small crack through the bone or a complete separation (displacement) of the bone fragments.
It is important to understand that in a healthy wrist, a significant force needs to be transmitted across the scaphoid bone in order to break it. This is why, majority of patients can recall a particular ‘moment’ i.e. accident/movement which had led to such outcome (sports injuries, road traffic accidents, fall on outstretched hand etc.) when the wrist joint had been loaded significantly and forcefully twisted at the same time. It is very unusual to sustain scaphoid fracture through usual daily activities or trivial trauma i.e. just carrying a heavy bag, gently twisting the wrist, carrying out ‘desk based duties’ and so on. A clear and thorough history of events preceding possible scaphoid fracture is therefore, of outmost importance.
Some scaphoid fractures do not get recognised until much later i.e. many remain ‘silent’ for many years. It is not uncommon for doctors to discover an old nonunion of the scaphoid bone on X-rays after a trivial, more recent wrist injury or sprain. Patients themselves get astonished to hear that the recent injury was clinically irelevant, except that it led to a discovery of an old, long standing scaphoid break. Of course, scaphoid non-unions are much more difficult to treat and their discovery is likely to have a drastic impact on wrist function and ability to work, especially if not treated successfully.
The symptoms of a fresh fracture of the scaphoid bone usually include pain and tenderness in the area just below the thumb. This might be associated with swelling around the wrist.
Symptoms of a nonunion of the scaphoid bone are more subtle. You may have pain only when you use your wrist. The most common symptom of a nonunion is a gradual increase in pain over a long period of time.
Over several years the nonunion can lead to degenerative arthritis in the wrist joint.
In most cases, a history suggestive of possible scaphoid injury, clinical signs and plain radiograph (X-rays), will discover a scaphoid fracture.
Sometimes, however the X-rays taken immediately after the injury may not show a break (Picture 2). This usually happens because the fragments remain well aligned and/or they maintain good vascularity and density despite the break. With true fractures, however, 2-3 weeks later, the metabolism of the bone will cause inevitable changes which are likely to be depicted by the X-rays. If the fracture is not visible at the beginning and a doctor remains highly suspicious of a scaphoid injury, wrist cast should be put on for the first 2 weeks and X-rays repeated at fortnight.
Other tests that might offer, more reliable early evidence of scaphoid fracture are a magnetic resonance imaging (MRI) scan and/or bone scan. A decision to order those additional investigations (without unnecessarily ‘over investigating’ condition) should be made on clinical grounds and individual circumstances, ideally judged by an experienced clinician.
When a scaphoid fracture is recognized on the first X-ray, treatment should ideally be started straight away, or at least within the first week whilst bone healing is most potent.
In general, scaphoid fracture can be treated with immobilisation (cast) only or surgery. Which treatment is chosen, depends on several factors – type of fracture, position of fragments, time elapsed since accident, additional injuries, patient personal circumstances etc.
Non-surgical Treatment (Immobilization only)
If the fracture is identified immediately, bone fragments are in good alignment and at a ‘prognostically favourable’ part of the scaphoid (middle of the bone), wearing a wrist cast for 8-12 weeks will lead to successful union in approximately 85% of patients. The cast holds the scaphoid bone very still while it heals. Repeated X-rays at 4-6 weeks intervals should check and confirm the progress of bone healing. Even with this type of (supervised) treatment, there is still a risk that the fracture may not heal well and will become a nonunion in approximately 15% of patients.
Surgery is indicated whenever fragments are rotated or sit far from each other (displaced fractures) or there is an evidence of poor healing with cast only. Some surgeons report good results doing surgery right away even if fragments are not displaced i.e. are close to each other. In such circumstances, operation is performed through a tiny, ‘key-hole’ incision (so called percutaneous access) in order not to disturb tissues and important wrist ligaments.
Modern surgical treatment of scaphoid fracture involves insertion of a special screw (rarely just simple pins) within the scaphoid which keeps two fragments firmly together (Pictures 3 and 4). In a trully fresh injuries, fragments just need to be realigned well. Compression properties of the scaphoid screw will then act favourably on solid fixation and successful bone healing. If the bone has been badly damaged or a lot of scarred bone needs to be removed, the bone graft might need to be placed between the broken fragments before screw is placed in. A bone graft can stimulate healing on the surface of the bones. A bone graft involves taking bone tissue from another area (for example, the forearm or the hip bone) through the small, additional incision.
Successful surgery allows people get back to activity faster than when wearing a cast for up 3 months. The screw acts as an internal splint, so external cast and total wrist immobilisation are not required.
Operation is performed on a day care basis under general or regional (anaesthetic is injected into the armpit to numb the entire arm) anaesthesia.
It always helps to plan things in advance of surgery and adjust work and life activities accordingly. Therefore, please consider the following issues prior to your operation:
- Anticoagulation medication (Aspirin, Brufen, Warfarin, Clopidrogel) should ideally be stopped few days before the operation to reduce the risk of bleeding, but advise from the clinician who prescribed them is wise beforehand. I would strongly advise you to stop smoking prior to surgery as this can badly affect the outcome of surgery and increase complication rates.
- Please make sure that you arrange to be collected from the hospital as you will not be able to drive after the surgery.
- Plan your time off school / work / sports.
- Allow at least few weeks after surgery before considering a holiday.
When scaphoid fragments fail to heal within the first 3 months of injury, a condition called ‘nonunion’ develops (Picture 5). This can happen when treatment failed to result in bone healing or fresh scaphoid fracture has not been recognised and/or treated at all.
In a simple nonunion, the two pieces of bone fail to bond together. In more serious and prognostically worse scenario, the upper half of the fractured bone loses its blood supply and actually dies. This condition is called avascular necrosis. The scaphoid bone is at particular risk for avascular necrosis due to it’s peculiar anatomy. Only one small artery enters the bone, at the end that is closest to the thumb. If the fracture tears the artery, the blood supply is lost. Avascular necrosis becomes easy to see on X-rays several months after the injury.
When nonunion is diagnosed relatively soon after the accident (up to 4-6 months), prolonged cast wearing might eventually lead to delayed bone union but in most instances, surgery is required. In addition to insertion of a screw as described above, scarred scaphoid fragments need to be cleaned first, unhealthy tissue removed and lost part of the bone rebuilt by inserting a fresh bone graft (Picture 6). Grafts needs to be harvested from another area (usually forarm bone close to the wrist or the hip bone). This is obviously, more complex and riskier undertaking then that related to early surgery.
When scaphoid fracture is managed non-surgically cast is worn for 8-12 weeks (most commonly 8). Most of my patients wear a cast which immobilises wrist only; rarely thumb and/or elbow joint need to be made still too. Fingers should be left free allowing and encouraging early full range of motion in order to prevent stiffness. Very simple, light tasks can be performed (writing for a short period of time, holding light objects) very early, but driving and heavy manual work is prohibited for the whole period of immobilisation i.e. 8-12 weeks.
During immobilisation, X-rays are ordered in the clinic at 4 weeks intervals to ensure good fragment position and bone healing. The wrist will be stiff and weak from being in the cast so the hand therapy is required after cast removal.
Rehabilitation following surgery
Exact rehabilitation protocol depends on type of operation performed, but in general, after surgery period of immobilisation with the splint is shorter (4-6 weeks) and overall rehabilitation more proactive from the start. This is possible because of inherently stable fixation of bone fragments with internal screw. Scars are usually very short and their location in the wrist (front or back) depends on exact location of the fracture. All scars heal within 2 weeks and wounds should be kept dry during that time.
Percutaneous fixation – scar is up to 1cm long. It is most commonly placed on the palm side of the wrist, but sometimes it can be at the back. Splint is usually not needed, but some patient like the comfort it provides for up to one week after surgery. Wrist movement is encouraged from the start to prevent stiffness and improve bone vascularity with movements. Recovery is usually limited to 3-4 weeks, but return to contact sports and heavy manual duties is not advised for the first 2 months.
Open fixation with/without bone grafting – scar is usually between 3-5 cm long. Depending on exact fracture location, it can be on the palm side of the wrist, extending into the lower forearm, or at the back of the wrist (usually hidden within skin creases). Because wrist ligaments are interfered with during operation, cast is required for a minimum of 4-6 weeks postoperatively to allow their healing and consolidation. When bone graft is used, immobilization is somewhat longer up to 10 weeks. Rehabilitation should always be guided by knowledgeable hand therapist and can take between 6-8 weeks. Therapists combine rest and mobilization in order to stimulate and support healing, yet prevent stiffness and scar problems.
If you have any concerns following your surgery please contact:
Picture 1: Bony anatomy of the wrist joint; S - Scaphoid bone
Picture 2: Sometimes fracture might not be easily visible on the X rays taken soon after the accident, but repeated investigations, usually 2-3 weeks later, will depict the abnormality Picture 3: Scaphoid screws is supposed to fit entirely within the substance of the scaphoid so it does not impede gliding between the surrounding wrist bones; the difference in the thread pitch along (the whole length or only ends) of the screw facilitates compression between the broken fragments - an important parametar for bone healing
Picture 4: Position of the scaphoid screw at the end of the procedure
Picture 5: Old scaphoid non-union - broken fragments failed to unite
Picture 6: Treatment of non-union requires interposition of the bone graft between scarred scaphoid fragments before the screw is inserted across all three pieces
|Hospital stay||Day care; one night stay if bone graft is harvested from the hip|
|Surgery time||1 - 1.5 hours|
|Skin wound healing Bone healing||2 weeks 6-8 weeks|
|Splintage||1 week (percutaneous fixation) 4-8 weeks|
|Hand therapy||4-8 weeks|
|Washing||from week 2|
|Time off work||1-2 weeks for office based work; 4-6 weeks for manual work|
|Sports and exercise||no contact sports for 8 weeks; 3-4 weeks for activities sparing wrist joint|
|Driving||from week 2 (percutaneous fixation) from week 8 (you should be able to perform emergency stop comfortably); please check details with your insurance company|
|Full recovery||12 weeks|