FRACTURE TO THE SCAPHOID BONE
The scaphoid bone is more commonly fractured than the other carpal bones. The lesion develops mainly during the active period of life.
Full anatomical knowledge about the local region is essential before contemplating management of this condition.
MECHANISM OF INJURY
A fall on an outstretched hand with radial deviation sandwiches the scaphoid between the radius and the carpal bones.
SITE AND NATURE OF FRACTURE
The healing process depends considerably upon the site of fracture. The lesion may involve the tuberosity, upper pole, waist or proximal pole of the scaphoid. More than seventy per cent of the fractures happen at the mid part of the bone.
The scaphoid bone is devoid of muscular attachments, has less periosteum and being mostly covered by articular cartilage, suffers from a poor blood supply. The blood vessels enter the bone through the distal and mid part of the bone.
Fracture through the proximal part can therefore lead to an impaired blood supply and can interfere with the healing mechanism of fracture.
TYPES OF FRACTURE
Direction: The direction of fracture may be of a vertical, transverse or oblique type. The vertical one heals slowly in comparison with the transverse variety. The lesion may be a simple hairline fracture, fracture without displacement, with complete displacement or that of a tilting variety.
This is a serious condition and can often be overlooked and wrongly diagnosed as sprain of the wrist-joint. Radiological interpretation may be misleading when the fracture line is not a clear one. This will lead to mismanagement of the case unless delayed x-ray is done.
Clinical examination: Careful examination is important. Pain, swelling, restricted painful movements of the wrist-joint along with tenderness over the snuff box should arouse one’s suspicion.
Radiological evidence: The scaphoid bone cannot be visualized properly by a simple anteroposterior and lateral view. Fractures can be overlooked when only two x-ray views are taken. Right and left oblique views are necessary for correct interpretation.
Delayed x-ray: A hairline crack or undisplaced fracture may not be visualized by x-ray when this is done immediately after the accident. Re x-ray after a period of ten days will enable the fracture line to be distinct and identification becomes easier.
95% of cases of scaphoid fracture unite satisfactorily when managed properly. Complete immobilization is maintained until the radiological evidence of union is present. This period is considerably longer in some cases and repeated x-rays with the wrist-joint out of plaster are needed.
The line of treatment is based upon the amount of fracture displacement.
- Fracture without displacement or with little displacement
Immobilization: In these types of cases immobilization is done without any manipulation. The plaster cast includes the proximal phalanx of the thumb and extends from near the metacarpal heads to below the elbow-joint. The wrist is kept in a position of radial deviation. Many surgeons apply the plaster cast with the wrist-joint in neutral position and do not include the proximal phalanx of the thumb. Union usually takes place after a period of 6-8 weeks. At the end of this period, x-ray is done after removal of the plaster. Re-application of the plaster cast for another 6-8 weeks is performed when evidence of union is absent.
2. Displaced fracture
Manipulation:Successfulclosed reduction of displaced scaphoid fracture may be difficult. In selected cases manipulation may be attempted which depends mainly on the site of fracture and nature of displacement. Under general anaesthesia restoration of alignment of the fractured segments is done by simple finger pressure and by altering the angulation of the patient’s wrist-joint.
Immobilization: The technique of immobilization and its management are done on the same principle as in the case of undisplaced fracture.
The common complications of fracture of the scaphoid bone are as follows:
- Osteo-arthritis of the wrist-joint.
Treatment of Complications: In most cases, treatment is required when symptoms are present. Some patients with non-union may remain asymptomatic and do not require any treatment. Surgery is not usually contemplated in elderly patients but may be necessary in the younger age group. The surgeons use medical implants and orthopedic tools to perform surgery and these are provided by the top orthopedic surgical implants manufacturers.
TYPES OF OPERATIONS
- Bone peg insertion: Bone peg insertion can be done after obtaining bone from the radius, ulna or tibia. Bone peg is an orthopedic implant.
- Styloidectomy: The radial styloid process is removed, which may help in obtaining a painless wrist.
- Excision of the necrosed segment: Excision of the fractured segment can be done when the fragment is small and operative procedures have failed.