Sprained thumb is the most common trauma during ski falls. The seriousness of this sprain must absolutely be evaluated by a specialist to choose the treatment under penalty of significant sequelae.
Alpine skiing is readily associated with trauma to the lower limb, while injuries to the upper limb are more frequent. The sprain of the internal ligament of the metacarpophalangeal (MCP) of the thumb thus represents the trauma most frequently found during the practice of alpine skiing. Skiing is not the only cause of a sprained MCP joint of the thumb and ball sports or trauma during heckles or brawls can also cause this type of sprain.
75% of hand injuries in skiers
Sprained thumb, at the joint between the 1time and the 2e phalanx (the “metacarpophalangeal”), is an extremely common trauma (75% of injuries to the skier’s hand). In skiing, it most often occurs in the context of a fall with sudden separation of the thumb outwards (in “abduction”).
In 90% of cases, the internal lateral ligament is affected. The pain is usually sharp and associated with a cracking sensation. The swelling is rapid but modest. The pain is violent when the thumb is mobilized, located on the internal and dorsal part of the joint.
Look for signs of gravity
A thumb sprain must always be considered serious a priori and in the event of a thumb injury while skiing, it is important to establish a diagnosis of seriousness. If in doubt, the x-ray should precede the examination. The signs of examination are the first criteria of severity: notion of cracking or dislocation, swollen thumb and major functional impotence, existence of a hematoma on the dorsal face of the thumb. An X-ray of the face and profile of the PCM of the thumb must then be immediately requested to look for a bony tear at the base of the first phalanx. If he is present, the more in-depth examination should be abandoned and the operation should be carried out after the examinations.
In the absence of any sign of clinical seriousness or bone lesion, it is necessary to look for signs of instability on the more detailed examination which is carried out by the doctor: pain when gripping between thumb and index finger, that the patient does not arrive not to be remembered when the examiner pulls on it (“leaf sign”), painful hyperextension of the thumb, looking for lateral instability of the thumb joint.
Checking for instability of the thumb
The examination of the possible instability is comparative and consists in grasping the first phalanx of the thumb and impressing it with an outward movement relative to the second phalanx of the finger (valgus movement). A difference in valgus deviation of 25 to 30 ° from the opposite side indicates the severity of the sprain.
In the event of a severe sprain the thumb can be deviated abnormally with some pain which indicates the rupture of the ligament and a surgical intervention must then be performed to repair the torn ligament.
Because of the pain and swelling this examination is sometimes difficult to bear “hot” and a second examination, after a few days of immobilization, may be necessary to confirm the diagnosis. If the joint is stable, then it is a mild or moderate sprain.
A few exams complete the assessment
An X-ray of the thumb should be taken so as not to overlook a more severe injury than a sprain, namely a dislocation of the thumb (the joint is no longer in place), or a fracture of the thumb.
It is common to find on the X-ray a small bone tear at the base of the first phalanx corresponding to a ligament tear and therefore witness to a sprain of the internal lateral ligament.
Ultrasound with a specialist has become an effective means of finding a Stener lesion and therefore of establishing the surgical indication.
Treatment depends on severity
Not all sprains justify surgical treatment: indeed the rupture of the ligament can be null (simple stretching) or partial which does not destabilize the joint, and an orthopedic treatment will be proposed: immobilization with a resin or a plaster cast. which blocks the metacarpophalangeal joint of the thumb but leaves the wrist free: it will be kept for 10 days in the event of a mild sprain and three weeks in the event of a moderate sprain with incomplete rupture.
After the cast is removed, the injured person will gradually regain mobility of the thumb but must remain cautious for two months. If mobility does not return spontaneously, a few rehabilitation sessions will be necessary.
Surgery is essential in the event of a serious sprain
The treatment is imperatively surgical in the event of serious sprain of the metacarpophalangeal of the thumb with a repair of the ligament (“suture”) followed by an immobilization of 4 to 6 weeks by plaster splint. It is not urgent and can be performed “cold” for ten days.
If the injured person does not have the operation for the first 10 days, the ligament may not heal resulting in loss of strength, pain and sometimes instability of the joint when clamping between the thumb and thumb. index finger (annoying because you can no longer grab an object by squeezing it with your thumb).
It is then necessary to consider a more delicate surgical intervention consisting in replacing the ruptured ligament which is no longer repairable because it is retracted. It will then be necessary to use a wrist tendon to recreate this ligament (“ligamentoplasty”), which also gives good results, but which is more complicated.
We must relieve the pain
Pain should be relieved by pain medication. They can persist for three to six months after the trauma or the operation. There may then be “climatic” pains with reappearance of painful discomfort in wet weather. In the majority of cases, the person does not report any pain after 6 months. Thumb function is excellent 98% of the time with a strong and stable thumb-index clamp.
The swelling of the joint is sometimes sequelae and permanent. There is no effective treatment for reducing joint swelling. Resumption of sport is done in the 3rd postoperative month with a strapping at first.
Long-term risk of osteoarthritis
In the absence of repair or in the event of poor repair, there is instability of the joint, with reduced grip strength and abnormal movements.
Due to these movements and the abnormal functioning of the joint, osteoarthritis can develop over time. Osteoarthritis is signaled by the reappearance of pain that no longer existed for years.
When the joint is destroyed, it is possible to achieve definitive immobilization of the metacarpophalangeal bone by fusion of the bones in a functional position (“arthrodesis”).
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