Why is ligament repair necessary?
The metacarpophalangeal joint of the thumb is extremely well adapted to the hand’s grasping function, requiring exceptional stability.
This stability is guaranteed not only by the thumb muscles, but also by three essential ligament structures. At the front, a thick palmar plate prevents hyper-extension, while internal and external lateral ligaments ensure stability at the sides.
Damage to the medial collateral ligament on the index finger is the most common, particularly when skiing. During a fall, a forced movement can rupture this ligament, which is robust and plays a major role in the stability of the thumb’s metacarpophalangeal joint.
The ligament ruptures at the base of the first phalanx and retracts due to its elasticity, causing other structures to interpose. Natural healing then becomes impossible, as the ligament remains distant from its attachment point on the phalanx. In this case, surgery is required to restore the ligament’s position on the base of the first phalanx.
In the absence of intervention, the ligament cannot heal properly, resulting in loosening of the thumb metacarpophalangeal joint, potentially leading to actual joint instability, and pain that will make any action requiring force difficult or impossible. The treatment of secondary joint instability is more complex than the initial repair of the ligament.
X-rays are routinely taken from the front and side, and may reveal a fracture or displacement of the base of the first phalanx.
Procedure
Anesthesia:
Before surgery, the anaesthetist will gather information about your state of health, medical history, allergies and any medications you are taking, especially those that could influence the procedure (such as anticoagulants or antiaggregants).
He or she will perform a medical examination and explain the anesthesia method he or she plans to use. In most cases, this will be locoregional anesthesia of the upper arm, or local anesthesia of the elbow or wrist.
He will check that you have respected the required fasting period (at least six hours before the procedure).
The procedure :
The procedure is performed with a pneumatic tourniquet (similar to blood pressure measurement) placed on the arm to prevent bleeding in the surgical area.
The surgeon makes an incision in the side of the thumb and uses various techniques to repair the ligament:
If the ligament rupture is pure, a simple suture is performed using an absorbable thread. If necessary, the ligament can be reinserted at the base of the first phalanx using a mini anchor driven into the bone, firmly securing the suture. If a bone fragment is present, it is reduced to the correct position and secured with a pin or mini-screw. The skin is usually closed at the end of the procedure.
This is followed by three to four weeks of immobilization in the form of a splint, plaster or resin gauntlet. This immobilization concerns the first phalanx of the thumb, leaving the second phalanx free. The surgeon may decide not to go ahead with the operation in the event of material problems, significant retraction of the ligament (if the operation is performed after 10 days) or fracture of a small bone fragment during repositioning, which could necessitate its removal.
The aftermath:
It is essential to mobilize the joint at the tip of the thumb, which remains free and can stiffen easily.
Other potential complications include healing problems under the plaster cast, rarely serious, suture failure in the case of insufficiently strict immobilization, and in the case of bone reduction, non-union of the fragment (pseudarthrosis), generally without functional consequence. Delayed surgery makes suturing the ligament more complex and less effective, which can lead to laxity.
After removal of the immobilization, active mobilization of the whole thumb, including the operated joint, is important, avoiding strain and trauma. In most cases, rehabilitation sessions are recommended.
In the longer term, the removal of bone fixation hardware (pins or mini-screws) may be necessary in case of discomfort.
Your intervention in practice
This procedure is performed on an outpatient basis, which means that you will not be admitted to hospital overnight.
However, it is important to follow certain precautions:
- Respect the six-hour fasting period before the procedure.
- Make sure you’re accompanied, as you won’t be able to drive after the procedure.
- Avoid making appointments on the day of the operation, even if it takes place in the morning.
- When you return home, wear a sling to keep your arm in position. The anaesthetic will continue to have an effect after the operation.
- Refrain from smoking, as it can impair finger microcirculation, delay tissue healing and increase the risk of infection.
