Definition of thumb sprain
The sprained thumb is one of the most frequent hand injuries. It is the most frequent form of sprain along with the sprains of the proximal interphalangeal (PIP) joints of the long fingers. A thumb sprain manifests itself as acute pain in the thumb as a result of a fall on the hand.
In most cases, this thumb injury corresponds to the lesion of a ligament in the metacarpophalangeal (MCP) joint, usually the medial collateral ligament (internal), and more rarely the lateral collateral ligament (external).
Video of arthroscopic treatment of a thumb sprain:
Thumb sprain diagnosis:
The clinical examination is the best examination; it should be bilateral and comparative and look for laxity of the metacarpophalangeal thumb joint in the frontal plane (valgus-varus) When no laxity is found, a medical treatment consisting in immobilization (bespoke orthosis) for a month will be sufficient.
If the thumb is lax at the MCP hand surgery will be necessary to repair the thumb’s ligaments.
An X-ray of the thumb must always be taken to look for a palmar subluxation of the MCP or a corner fracture of the phalanx which corresponds to a tearing of the ligament at the bone. When a displaced fracture with tearing is found, thumb surgery is required. In case of diagnostic doubt, an ultrasound scan of the hand focusing on the thumb’s ligaments can prove useful; this test will look for a Stener lesion, in particular, that is to say an avulsion of the medial collateral ligament that passes over the adductor aponeurosis of the thumb’s extensor apparatus.
Hand surgery will thus be justified:
- if there is a displaced fracture with a tear (avulsion)
- if there is articular laxity of the thumb’s MCP
- if there is a Stener lesion
Benefit of arthroscopy in thumb sprain surgery
For sprained thumbs, arthroscopy has many benefits:
1. diagnostic benefits: arthroscopic thumb sprain surgery is the only technique allowing a 360° evaluation of the ligaments’ lesions, while with open surgery, these can only be examined on one side of the thumb. Conversely, thumb arthroscopy makes it possible to evaluate anterior, median and lateral lesions.
2. therapeutic benefits:
- the extensor apparatus and the dorsal aponeurosis are spared as much as possible
- joints bleeding and inflammatory synovial membrane are evacuated
- precise surgical repair of each of the thumb’s ligaments is made possible by placing one anchor or more.
- arthroscopy greatly helps reducing scars.
All of these factors make the recovery of the thumb and the convalescence of the hand easier.
Arthroscopic thumb sparin surgery :
This hand surgery is performed under regional anaesthesia, on an outpatient basis. The hand is put under slight traction applied along the thumb’s axis. Only two 2-mm incisions will be performed. The 1.9 mm arthroscope (camera) is inserted through a posterior portal with a lateral instrumental portal allowing the evacuation of joint bleeding and inflammatory synovial membrane.
The surgical procedure begins with a complete assessment of the damage to the capsule and ligament of the thumbs’s joint.
Once the rupture of the collateral ligament has been identified, a screw-in anchor can be inserted in the base of the thumb’s phalanx.
Using a common “shuttle relay”arthroscopic surgery technique, each of the strands can be passed in the ligament of the thumbto be repaired.
Traction is then released to tie the knots together and thus insert back the damaged thumb’s collateral ligament.
Surgical incisions do not require any stitches. One week after surgery, the dressing can be permanently removed. Immobilization by <bespoke thumb orthosis must be kept for 3 weeks.
Recovery after surgery on sprained thumb
The hand dressing can be removed after one week. The thumb must be immobilized for 3 weeks, daily tasks using the thumb can resume right after the orthosis is taken away.
Specific hand rehabilitation is not always necessary.
Avoid forceful movements with your hand (>1,5 kg) for 2 months. Typically, the thumb is slightly sore and there is discomfort in constrained movements for almost 3 months. To resume rugby, the hand and the thumb will require taping at the beginning.