Chronic Achilles Tendon Rupture
What do we mean by the term "chronic Achilles tendon rupture"? When the Achilles tendon ruptures, it is usually a catastrophic event, which is immediately noted by the patient. Usually, the rupture is associated with an audible pop, followed by pain and weakness in the leg. As noted in the section on acute ruptures of the Achilles tendon, the ideal treatment is operative repair. Generally, it is preferable to perform this surgery within a few weeks following the rupture. When the Achilles tendon rupture is not diagnosed promptly, the ends
of the tendon begin to separate (retract). This is a normal outcome,
since the calf (gastrocnemius) muscle will always contract pulling
on the end of the tendon where the rupture took place. As a result
of the constant pulling and inevitable retraction, a gap then occurs
between the ruptured ends of the tendon.
Walking and pushing off
with the foot become increasingly difficult. There are other muscles
in the leg that try to compensate for the loss of strength in the
Achilles and the leg muscle (the gastrocnemius) but these
are never sufficient to maintain the power and strength of the leg.
Usually therefore weakness occurs, and the patient will find it difficult to push off when walking and in particular going up and down stairs. As the process evolves, the toe muscles have to work extra hard, and due to the extra workload on the these muscles of the leg, the toes
begin to curl and may even get permanently deformed.
|This is an MRI of the leg after a chronic rupture of the Achilles tendon. The normal tendon is seen as the black round tube. An MRI is essential to plan treatment of the chronic Achilles rupture.
Here we see a typical chronic rupture of the Achilles tendon. The small hooks are retracting the skin away, and you can see the one end of the tendon which is quite healthy looking and a large gap with stuff that looks a little like spaghetti toward the heel bone. This is the effect of the tendon retracting up into the leg.
The reatment of a chronic rupture of the Achilles tendon will require surgery. If for some reason the patient cannot tolerate surgery, or is medically not fit to undergo an operation, then the treatment can be initiated
with the use of a brace.
While a brace never restores the full function of the leg, it does
permit some increased strength in push off since a spring is attached
to the brace that fits inside the shoe. Surgical treatment should
however be performed once the diagnosis is made. If the rupture has been present for many months, there is no urgency to the surgery, but one really should not wait too long, since the Achilles tendon continues to pull up into the leg and the gap between the tendon ends gets larger, making the surgery more difficult.
The type of surgery performed depends on the size of the gap between
the tendon ends and the extent of separation that is present. If
the separation is minimal, then the tendon ends can be stitched together
much like what was described above for acute Achilles rupture. If
the separation is more significant, then other procedures need to
be performed.As the gap gets bigger, the options then range from using a strip of the lining of the existing Achilles (called a V-Y advancement), using another tendon as a tendon transfer, or even using an Achilles tendon graft which comes from the tissue bank.
It is al ways preferable to use the exisiting Achilles and not a graft. DR Myerson has developed a method of bringing the tendon ends together so that a large gap can be bridged together without using a graft or a tendon transfer.
A tendon transfer is only used when there is a massive gap present, or the Achilles has been ripped off its' attachment on the heel bone. When it comes to using a different tendon to substitute for the Achilles there are a few tendons which can theoretically
be used, but the tendon transfer which is preferred uses the second strongest
muscle in the leg, the muscle to the big toe (the flexor hallucis
longus). The disadvantage of this operation is that the flexor hallucis
muscle is not as strong as the Gastrocnemius which powers the leg.
Nonetheless, patients are able to push off fairly comfortably with the tendon
transfer and can even participate in some sporting activities. This
operation can be performed through a very small incision on the back
of the ankle. Some orthopedic surgeons like to make a second cut
in the arch of the foot to retrieve the tendon for the transfer,
but this is not at all necessary.
||This is a very large defect or gap
between the ends of the tendon. This cannot be approximated
in any way without a graft of some sort. The gap needs to
be bridged in some manner
|This patient sustained a rupture
of the Achilles tendon which was not diagnosed for one year.
||Note the difference in the incision here
in this patient, where the tendon to the big toe (the flexor
hallucis) was used to replace a chronically torn Achilles tendon.
In some patients, the gap between the ends of the Achilles
rupture are too great to use any type of flap from the Achilles,
in which case a tendon transfer is used as you can see here.
Occasionally, the tendon transfer of the flexor hallucis longus is not necessary and a long strip of Achilles tendon is used to slide from top to bottom to restore continuity to the length of the Achilles tendon, (called a V-Y advancement). Note the gap in the picture below, which is too large to correct using stitches alone. Either a graft or a tendon transfer must be performed. The graft can be taken from the back of the leg by sliding down a piece of the tendon (called a V-Y advancement), or using the tendon to the big toe (called the flexor hallucis longus).
Occasionally, we use a graft taken from a cadaver (called an allograft Achilles). This has tremendous advantages, in that the muscle of the patient is not weakened, and is attached to the end of the tendon or directly to the heel bone. This is a very difficult operation, but will return and restore the most power back to the injured leg. The cadaver Achilles graft is used for very specific types of repairs in certain patients who need more strength in the leg.
Here you see a surgery of an Achilles graft (called an allograft) which replaced a really massive defect in the leg. You can see the graft being attached to the heel with two screws, and on the right hand picture, the graft lies under the remaining Achilles while the stitches are inserted.
Following this type of surgery no weight bearing is permitted for
two weeks. After that, the patient may walk in a removable boot.
It takes many months for strength to return to the limb. Recovery
of strength is fairly substantial, although never quite as good as
the normal muscle and tendon.