Conservative treatment of a complete rupture of the ulnar collateral ligament of the thumb

A partial or complete rupture of the ulnar collateral ligament of the
metacarpophalangeal joint of the thumb, skier*s thumb, is an often-encountered
problem. It concerns 86% of all injuries to the base of the thumb. The
estimated incidence in the US is approximately 200,000 patients per year [2].
The incidence in the Netherlands is not known. In the last four years, we have
diagnosed approximately 85 patients in our own hospital. Skier*s thumb is the
result of a hyperabduction trauma of the thumb. It can occur with any fall on
an outstretched hand when a thumb that is already in abduction receives an
extra valgus stress. Skier*s thumb refers to the fact that this injury is often
seen in skiers who fall while holding on to their ski poles. This type of
injury is also seen in other sports, especially those that use a stick or ball,
such as hockey or basketball. During a query in our own inner-city hospital,
only 10% of the patients had skier*s thumb due to an injury acquired during
skiing. Often, these patients also presented with a delay because their injury
occurred during a holiday, and they waited until they came back home to see
their own physician. A fall on the hand, usually from a bicycle or motorcycle
(in which the thumb gets stuck behind the handlebars), is the most common cause
of skier*s thumb in our hospital, seen in approximately 40 % of all patients.
Another sport, especially soccer or fighting, was the cause in 30%. The ulnar
collateral ligament is made up of two parts, the proper collateral ligament
(PCL) and the accessory collateral ligament (ACL). The PCL has its origin
proximal to the base of the head of the MCP-1 joint and insertion on the volar
side of the proximal phalanx. The ACL has its origin just palmar of the PCL and
runs parallel to the PCL to its insertion on the proximal phalanx. Together
they ensure the ulnar and volar stability of the base of the thumb. However,
there are other components that also take part in creating stability in the
joint. They can be divided into static and dynamic components. The most
important dynamic component is the adductor pollicis muscle. This muscle has
its insertion onto the proximal phalanx partly superficial to and partly deeper
than the UCL. Most of the time, the distal end of the UCL ruptures. A Stener
lesion occurs when this part gets stuck between the proximal edge of the still
intact aponeurosis of the adductor. Because this aponeurosis stands between the
UCL and the bone, it is thought that this injury cannot heal in this position.
Stener lesions occur in 64% to 87% of all complete ruptures and are usually
treated by surgical repair. If the MCP joint is in flexion, the PCL and the
dorsal capsule are taut and therefore the most important stabilizers in that
position. The reverse applies to the ACL and the volar plate, which are taut
when the MCP is in extension. This is important to know when testing the
stability of the joint. When laxity during testing is only seen with the MCP in
flexion, an isolated PCL rupture is suggested. If this laxity is seen in
flexion and extension, a complete rupture of the PCL and ACL is most likely.
Physical examination Usually the patient has pain, swelling and a hematoma at
the ulnar side of the MCP joint of the thumb. Sometimes a mass can be felt in
that area, which suggests a Stener lesion; however, it is not pathognomonic.
The UCL is tested by first holding the MCP in extension and applying valgus
stress to the phalanx. The same is done with the MCP in 30 degrees of flexion.
It is important that the thumb of the investigator is placed on the radial side
of the MCP joint to apply counter pressure to prevent possible rotational
effects. It is difficult to say when a true laxity of the joint is seen,
because the normal range of motion of the MCP joint differs per individual. In
most of the literature the standard is more than 35 degrees during valgus
stress and/or more than a 15 degrees difference compared to the contralateral
side to diagnose a total rupture. However, in a recent study in which laxity in
healthy test subjects was tested, it was found that 34% of all people have a
more than 10-degree left-right difference in extension, and 12% had a
difference of 15 degrees or more. In flexion this was seen in 22% and 3% of
patients, respectively. The advice of Ritting et al. in a recent review was
that instead of holding on to a fixed degree limit, the absence of a firm
endpoint during testing is a more reliable criterion when clinically diagnosing
a complete rupture of the UCL. However, this can only be reliable when the
investigator has enough clinical experience with testing the UCL. Often the
examination is too painful to perform and the results cannot be interpreted
correctly because of an uncooperative patient. Performing the investigation
under local anesthesia can be useful. A study by Cooper et al. described how
Oberst anesthesia (in which 1*2 ml of lidocaine is injected in the MCP joint on
the ulnar and radial side) increases the clinical accuracy from 28% to 98%
after an average of one week after the initial trauma. Sometimes the swelling
during initial presentation can stand in the way of performing a reliable
physical examination. In this case, one can decide to immobilize the hand and
re-evaluate it after a week, with or without using Oberst anesthesia. Only the
difference between a partial and a total rupture can be diagnosed with a
physical examination. A Stener lesion is a type of complete rupture that cannot
be differentiated from a total rupture in which the UCL is still close to its
insertion. As mentioned before, a swelling at the MCP does suggest a Stener
lesion but is not specific for one. This difference can only be visualized by
additional imaging or during surgery. The first step in imaging studies is to
make a plain radiograph in the AP and lateral direction to diagnose an avulsion
fracture that is mostly located on the ulnar side of the proximal phalanx. A
fragment is considered to be dislocated if it is displaced more than 1 mm or if
it is malrotated. If the plain radiograph shows no avulsion fragment but there
is a clinical suspicion of skier*s thumb, further imaging can be performed by
doing an ultrasound, CT, arthrogram or MRI. Which technique to use seems to be
determined by the physician*s preference; there are no clear guidelines about
this. MRI can be seen as a gold standard with a sensitivity of 96%-100% and
specificity of 95-100% [15,16]. However, this is a very costly technique, often
with long waiting lists. Treatment The treatment of skier*s thumb is different
for partial and a complete ruptures. This study only concentrates on complete
ligamentous ruptures. If there is an unstable joint for which no firm endpoint
is found during testing, surgery is considered the best treatment. This also
applies to Stener lesions because the general idea is that the UCL cannot heal
if it is not in contact with its insertion, even though no evidence can be
found in the literature to support this notion. Also, no trials have even been
set up to investigate whether a surgical intervention is really superior to a
non-surgical treatment. Some small studies were carried out to see whether
non-surgical treatment for a complete rupture could be equal to surgery.
Landsman et al. described 40 patients with a total rupture with and without a
Stener lesion, which were all treated only by immobilization. Thirty-four
patients were successfully treated this way; the other six still had complaints
of instability and pain and underwent successfull operations. Another study by
Pichora et al.reported that 3 of the 32 patients with total ruptures that were
treated non-surgically had persisting complaints that could not be resolved
with surgery; the same percentage that could be expected with regular operative
treatment (see below) Different surgical techniques can be used. Which one
applies depends on the anatomy of the lesion and can often only be decided upon
during surgery. The UCL can be fixated with a suture anchor or with
transosseous stitches. Results seem to be independent of the chosen technique,
and successful recovery to the patient*s level before the initial trauma occurs
in 90%-96% of all patients. This means that the question remains whether the
patients mentioned above (with persisting complaints after the first
non-surgical and later surgical treatment) would have benefitted from initial
surgical intervention. Ideally, the operation takes place within 2 weeks;
however, good results can still be achieved after 3*4 weeks. Afterwards, a
period of usually 6 weeks of immobilization is applied, after which a new
radiograph is made and physical therapy of the hand can be started. When the
pain has subsided and the range of motion has completely returned, the hand can
be completely used again. Usually this takes about 3 months. Patients with
worse outcomes are mostly patients with a delay in presentation. When repaired
in a timely manner, complications are rare. When they do occur, it usually
concerns neuropraxia of the radial nerve that arises secondary to traction,
swelling or stiffness. All are usually temporary in nature. Persistent
instability is very rare.

to investigate whether applying a conservative treatment for an unstable
ligamentous skiers thumb is equal to surgical repair.

an open randomised controlled trial

Patients will get a cast immobilisation instead of an operation.

Getting a conservative treatment will lower the burden of the patient (they
will not undergo surgery), which is a benefit. Risk of persistent
instability/complaints is very low, patients always have the choice to still
undergo surgury at a later stage with good results described in the literature.
Time of treatment is equal to regular treatment. Patients need to make 1 extra
visit one year after initial trauma and need to fill in questionnaires. This
does not take a lot of time (approx 15 min per visit)