Collateral ligament rupture of the thumb

from Wikipedia, the free encyclopedia
Typical skier's thumb in the x-ray with a torn bone ligament
Classification according to ICD-10
S63.6 Sprain and strain in one or more fingers
ICD-10 online (WHO version 2019)

The collateral ligament rupture of the thumb , also popularly known as the skier's thumb , is a common ligament injury of the thumb. The thumb kinks outwards (radially) in the base joint and the inside (ulnar) collateral ligament tears. The trigger is often a fall on the hand with an overstretched thumb spread, very common when skiing (hence the colloquial name). The collateral ligament usually tears off distally near the attachment point at the base of the phalanx, and occasionally the torn ligament can protrude proximally under the aponeurosis of the adductor pollicis muscle, which is then referred to as a Stener lesion and cannot be reduced. Sometimes the bony ligament is torn out, whereby a small bone fragment is visible on the x-ray at the base of the ulnar phalanx.

function

The ulnar collateral ligament ensures a firm grip on the thumb, and if the ligament ruptures, the thumb becomes painfully unstable and it is difficult to hold heavier objects securely between the thumb and long fingers. Later, there is a restriction of movement both in the metatarsophalangeal joint and in the distal joint, which cannot always be avoided even with surgical reconstruction, and in the case of chronic instability almost always premature arthrosis of the metacarpal joint of the thumb.

Symptoms

A collateral ligament rupture typically results in painful swelling, often with a bruise. However, this is unspecific and also occurs with a distortion or fracture . Therefore, a bone fracture, especially of the head of the first metacarpal bone, as well as bony ligament tears must be excluded by means of an X-ray.

However, significant tenderness over the ulnar collateral ligament and clinical instability are typical. For this purpose, a valgus stress, i.e. a bend in a radial direction, is carried out at the base of the thumb joint in a lateral comparison. If the opening is more than 30 ° more than on the uninjured side, this is clinically proof of a collateral ligament tear. The test is performed with 30 ° flexion in the metacarpophalangeal joint of the thumb in order to relax the accessory collateral ligament, which is tense in the extended position and conceals instability. Instability even in the extended position means that the accessory collateral ligament and palmar plate are also torn. If the pain is too severe, the stability test is carried out under local anesthesia . Instability can also be demonstrated radiologically with held images, but false negative results occur repeatedly if the thumb is not sufficiently valgus at the moment of the image. Some authors advise against holding recordings.

A Stener lesion can be detected by ultrasound with a 10 MHz transducer, but this requires special expertise.

therapy

X-ray of a torn ligament on the left thumb. The fracture was fixed with a mini-fragment screw.

The therapy consists initially of immobilization, possibly with a plaster splint, and pain therapy as well as cooling and holding up the hand. An operation is considered necessary if there is clinically proven instability due to the consequential problems associated with chronic instability. Since torn fibers have a clear tendency to retreat and become scarred, an operation should ideally be carried out in the first two weeks after the accident.

The procedure is usually carried out under plexus or intravenous regional anesthesia . In the case of a rather rare interligamentous rupture, a U-suture is performed, while a bony ligament tear or a tear close to the attachment is often fixed with mini-bone anchors, small screws or a K-wire. Most often the ligament is torn on the palmar side at the attachment to the base of the phalanx. During the procedure, the metacarpophalangeal joint is also opened and inspected for accompanying injuries, and the palmar plate is checked for a possible tear due to hyperextension. A Stener lesion is already evident during preparation at the subcutaneous level and only requires another additional access to expose the folded portion of the ligament, while the ligament suturing can be performed as described.

After the operation, immobilization is usually carried out for up to two weeks in a radiopalmar plaster splint, in order to switch to an orthosis that secures the metatarsophalangeal joint after the skin suture has healed. This type of splint stabilization usually takes place up to the end of the sixth week after the operation, before the load can then be gradually increased. However, it is often recommended to avoid strenuous exercise for another three months.

If there is already painful chronic instability, a ligament plasty by means of a tendon graft is often recommended, for which the tendon of the palmaris longus muscle or, in the Eaton-Littler technique, a strip from the tendon of the flexor carpi radialis muscle , or a Periosteal flap folded over and fixed in place of the torn ligament. However, if there is already arthrosis of the basic joint, the joint is stiffened ( arthrodesis ).

literature

  1. Alphabetical directory for the ICD-10-WHO version 2019, volume 3. German Institute for Medical Documentation and Information (DIMDI), Cologne, 2019, p. 807
  2. a b c B. Weigel, M. Nerlich: Praxisbuch Unfallchirurgie , Springer-Verlag Berlin 2005
  3. R. Hoffmann: Checklist hand surgery Thieme-Verlag Stuttgart 1997