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.

Primary: to investigate whether applying a conservative treatment for an
unstable ligamentous skiers thumb is equal to surgical repair.
Secundary: to calculate the sensitivity and specificity of standardised
accurate physical examination when compared to an MRI scan (reference test)

The diagnostic part of the study is a prospective cohort study
The therapeutic part is an open randomised controlled trial.

Patients will get a cast immobilisation in stead of an operation.

Diagnostic part does not include and extra burden/risk
The therapeutic part: getting a conservative treatment will lower their burden
(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.
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)