Rupture of a digital extensor tendon at the level of the terminal phalanx is common and can cause significant disability.
It causes difficulty in making the finger “flat” with the hand, and the passively flexed distal phalanx catches whilst tucking sheets or reaching into a pocket. Catching a ball difficult and it is regarded as an important aesthetic loss in a woman. Because adaptive strategies are difficult it may merit surgical correction.
Conventional management is not always simple or effective.
In addition the “scientific” documentation of this injury is often poor, illustrating an incomplete understanding of the surgical biology.
Below are extracts from the most frequently consulted web sites.
It results from hyper-flexion of the extensor digitorum tendon (1), and usually occurs when a ball (such as a softball, basketball, or volleyball), while being caught, hits an outstretched finger and jams it – creating a ruptured or stretched (2) extensor digitorum tendon.
The splint allows the tendon to return to normal length (3), if the finger is bent during these weeks the healing process must start all over again. Surgery is used to reattach the tendon and is usually performed within a week of the injury
It should be determined via radiograph if the Extensor Digitorum tendon has avulsed from the phalange, which will require surgical intervention to reattach the tendon and should be done within 10 days of the injury. Surgical treatment is used when the mallet finger presents as an open injury or if the bony mallet involves more than 30% of the articular surface of the joint. If passive extension cannot be achieved, surgery will put the finger in a neutral position and drill a wire through the DIP to the PIP, forcing immobilization and eliminating patient compliance for re-injury(4).
There are errors here:
1. Not so. It is hyper-flexion of the distal inter-phalangeal joint. The extensor tendon cannot hyper-flex.
2. Incorrect. Breakage (rupture) occurs. The tendon cannot “stretch”.
3. Fanciful. The tendon is unlikely to return to “normal length”, because the natural tendency of muscle is to retract the tendon. No splint provides the forces essential to pull the tendon back distally and so draw the tendon ends anatomically together.
4. It is assumed that the author means ”non-compliance which will perpetuate the injury or increase the deformity”
AMERICAN ACADEMY OF ORTHOPEDIC SURGEONS:
AMERICAN SOCIETY FOR SURGERY OF THE HAND has good illustrations and valid comments: http://www.eatonhand.com/hw/hw015.htm
How Successful is the Treatment?
Although this may seem like a trivial or simple injury, a cosmetically perfect correction is not likely with any form of treatment. However, with proper therapy and effort on the part of the patient, this problem can usually be improved to a tolerable level most – that is, the end joint of the finger may not fully straighten, but it will work well enough to be used for normal activities.
• Unless the injury is due to a cut on the back of the finger or there is some other associated problem, many hand surgeons believe that the final outcome and complication rate are at least as good with splinting alone compared to surgical repair. This may change as new techniques are developed to improve the results of surgery.
• Surgery is a reasonable consideration if the finger remains unacceptably bent after a full trial of splinting or if splinting is not possible – for example, if a skin reaction develops beneath the splint. Surgery is only considered if the outcome of surgery is expected to be better than the outcome of treatment without surgery.
What Happens if you have no treatment?
• Without any treatment, the appearance and ability to straighten the end joint of the finger will not improve. Additionally, if the injury is less than a month old, the problem may be worsened by using the finger without a protective splint of some sort.
• If the injury is more than three months old and has not been treated, it is unlikely that it will get better or worse on its own. Injuries more than three months old are not likely to be improved with anything short of surgery.
Conventional, non-intrusive management of mallet finger by splinting will not correct deformities (but might prevent worsening).
If the deformity is minimal, or otherwise acceptable, non interference is the way to go. However, if leaving the finger “as is” is not acceptable, then surgical treatment is frequently attempted:
Surgical treatment, as currently practiced, falls into two types,
1. Attempts at repair. This has been attempted by suturing with wire and other materials where there is no fragment of bone attached to the tendon. If there is a fragment of bone then attempts to fix the fragment (by screws or wire) are usual. However the tiny fragment of bone often splits and surgical failure is common. Whilst this repair is healing the position of the finger must be retained (immobilized) by :
• Splinting for several weeks, or
• Pushing a steel pin through the fingertip, then down the marrow cavity of the finger bones. This causes an awkward projection of the pin which has to be kept dry and requires repeated bandaging for several weeks. This penetration of the fingertip can cause small portions of the skin to become “implanted” more deeply with a painful pseudo-tumor resulting. Infection is not rare
2. “Fusion” of the joint leaving it permanently stiff. This prevents some fine movements (such as playing some musical instruments), and leaving the hand as a whole marginally weaker. Fusion also requires immobilization, as above, for several weeks.
Surely there has to be a more certain, safer and quicker solution? A description of my long established technique for managing mallet finger is available in the Store.
The benefits of this technique are that predictable and accurate results can be obtained, and the procedure can be performed electively long after the injury.