The symptoms of scaphoid fracture are caused by the fracture of a wrist bone that lies between the spoke (lat. radius, a forearm bone) and thumb.
The scaphoid is a short bone and has an irregular shape, similar to a bean.
The exact position of the bone can be seen with splayed fingers: between the base of the thumb and the forearm, two fibrous strands protrude, in the middle of which is the spoke dimple (snuff pit); in this area lies the scaphoid bone.
The inner part of the bone has a rounded shape; he articulates via the scaphoid hump (tubercle) with the large polygonal bone.
The scaphoid bone is the carpal bone that most often suffers fractures, because it is the first to hit the ground in a fall and lies in a place where many external forces converge.
About 90% of bone injuries of the wrist affect the scaphoid bone, which plays a fundamental role in the stability and dynamics of the hand; the other 7 carpal bones, on the other hand, are rarely damaged.
It mainly affects young people engaged in physical and sporting activities.
With any trauma and fall that causes a sprain of the wrist, an injury to the scaphoid bone must be suspected.
Athletes can break their scaphoid in a fall with a motorcycle, bicycle, roller skating, football, basketball, handball, etc.; often the wrist is dislocated.
The danger of a scaphoid fracture is that it can develop pseudoarthrosis if not treated appropriately. The effects can last for a long time, including pain, instability, loss of strength and mobility, as well as altered dynamics of the hand.
Among the most dangerous injuries are displaced fractures with dislocation (dislocation) of the bone.
A scaphoid fracture is complicated because this bone is surrounded by cartilage almost everywhere; the cartilage tissue is poorly supplied with blood and thus only a few nutrients are available for the formation of the bone callus.
The trauma can also injure the nerves, arteries and ligaments, especially the ligament connection between the scaphoid and the lunar bone, the SL ligament.
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How does the scaphoid break?
A scaphoid fracture is caused by direct force, for example by a fall on the hand stretched backwards, i.e. the position that the hand occupies when catching an object.
This type of fracture plays an important role in orthopedics because fracture healing causes difficulties. In the past, almost half of the patients did not form sufficient bone callus to heal the lesion.
In trauma, the scaphoid bone is compressed and stabilized proximal (close to the body) by the spoke; the distal part, i.e. the scaphoid hump, on the other hand, must absorb the impact without finding support in other bones.
A fixed lever point is formed between two parallel forces acting on the bone ends.
The most fragile area is the scaphoid content, i.e. the transition that connects the bone body to the hump; this is where most scaphoid fractures occur.
The scaphoid tubercle is the distal part of the bone and is well supplied with blood; here a fracture occurs relatively rarely, but because of the better blood supply, the bone callus is formed more easily here than on the proximal side.
What are the symptoms of a scaphoid fracture?
Symptoms of scaphoid fracture include severe pain, swelling on the wrist in the depression between the spoke and thumb.
The movement of the wrist and thumb cause pain.
Everyday activities are severely restricted because many movements of the hand cause difficulties: clenching a fist, turning the hand (e.g. grabbing a door or window handle, pouring a glass of water), lifting objects, etc.
How is a scaphoid fracture diagnosed?
Young and active people who suffer trauma and have pain on the thumb side and swelling on the wrist should be thoroughly evaluated for suspected scaphoid injury.
When elderly people fall, the scaphoid bone breaks extremely rarely, usually the ulna and spoke are affected.
The clinical examination provides for axial compression of the thumb to the wrist; if severe pain occurs, the test is to be evaluated positively.
As confirmation of diagnosis, an X-ray is taken, on which bone injuries are clearly visible; in some cases, a CT scan or magnetic resonance imaging may also be necessary.
It is important to know that diagnostic imaging may not reveal the fracture line on the day of the accident; therefore, it makes sense to wait two to three days.
The X-rays are taken on different levels:
- frontal plane with wrist inclined towards the ulna or neutral;
- lateral;
- Oblique view at 45°.
Not all fractures can be detected on the X-ray, which is why a CT scan is often performed, which also indicates microfractures, or an MRI, which is not the ideal method for assessing bone injuries, but shows, for example, a small, fracture-typical edema on the scaphoid bone.
Finally, in the last instance, a bone scintigraphy can be performed if the doctor deems it necessary.
How is a scaphoid fracture treated?
Treatment of scaphoid fractures is one of the most controversial medical issues.
The problem with this bone is that, without proper treatment, it causes delayed consolidation and algodystrophy in 30% of cases due to insufficient callus formation; the consequences are pain and instability.
In extreme cases, the clinical picture can develop in proximal displaced fractures with complications in the direction of necrosis and cell death.
If it is an undisplaced fracture, the orthopedist will opt for conservative treatment and plaster the wrist and hand; this immobilization lasts 6 to 12 weeks.
Many doctors also include thumbs and elbows in the cast.
For the return to normal or almost normal state of health, magnetic therapy is important, which can still be started with plaster; in addition, rehabilitation and exercise therapy are useful.
Half of patients with displaced scaphoid fracture develop pseudoarthrosis, even with correct and immediate diagnosis and therapy; therefore, surgical treatment is usually preferred today.
A fracture is defined as displaced when the pieces of bone deviate from the maximum match by more than 1 mm.
Surgery is also recommended for open fractures or fractures accompanied by dislocation (dislocation) for the following reasons:
- short immobilization period;
- faster healing and return to work and sports;
- Prevention of negative effects, especially algodystrophy.
A fracture in the proximal section of the scaphoid bone is treated surgically because the blood flow in this part is not sufficient to initiate the process of forming the bone callus.
Since surgery is performed in the vast majority of cases for scaphoid fracture, one should decide on the procedure as soon as possible and not wait for weeks or months; in this way, the return to everyday activities can take place faster and with less pain.
What happens during the operation?
The surgical intervention consists of osteosynthesis, i.e. the two bone parts are joined together with the help of a tiny screw (Herbert screw); the screw serves to stabilize the fracture and holds the bone fragments together.
As a rule, Kirschner wires must be used, which hold the fragments together, which allows the breakage to be set up correctly.
The screw used for fixation must be inserted in the middle of the bone; if positioned at the end of the bone, the patient could not be completely cured.
The sick stay is short, the patient usually only has to spend one night in the hospital.
The operation takes about 20-30 minutes and is performed under local anesthesia, injecting the anesthetic near the nerves running in the armpit (plexus anesthesia).
The skin incision is very small, just under 1 centimeter long; after the procedure, the wound can be sutured with only 3 stitches.
In some cases, especially in the case of debris fractures (with numerous fragments), bone grafting is performed; the implants are removed from the hip or spoke.
A targeted transection for correction of the scaphoid bone (corrective osteotomy) occurs when the bone grows together irregularly and its shape does not harmonize with the other bones and carpal structures.
