CASE                                4                               

A 54-year-old, male banker was traveling in a bus when it jerked to a sudden stop. In an effort to stop himself from falling, he held onto the overhead bar. However, he continued to fall, and in trying to hold onto the overhead bar, he noticed immediate onset of pain in his ring finger. Thereafter, he was unable to flex it fully, immediately developed pain and swelling, and presented to your office 4 days later with a swollen and painful ring finger (Fig. 4–3B). Examination revealed a swollen finger with bruising over the pulp (Fig. 4–3A). He was able to flex his proximal interphalangeal (PIP) joint to some extent, but was unable to flex his distal interphalangeal (DIP) joint. Radiographs did not show any bony injury of the finger.

Figure 4–3 A–B

The most likely diagnosis is:

1. Sprain of the DIP joint

2. Avulsion of the profundus tendon from its attachment to the base of the distal phalanx

3. Dislocation of the DIP joint

4. Fracture of the distal phalanx

Discussion

The correct answer is (B). This injury is also known as a “jersey finger” when the profundus tendon is detached from the base of the distal phalanx. Such patients usually present with a swollen digit and usually with bruising of the pulp. They also demonstrate lack of profundus function and the inability to flex the DIP joint. In this patient, the radiographs were unremarkable. Therefore, he does not have either a DIP dislocation or a fracture.

After evaluating the patient, the next step in management of this injury would be:

1. Gentle rehabilitation

2. Splinting for 3 weeks followed by a range of motion program

3. Open repair of the avulsed profundus tendon

4. Pinning of the DIP joint in 30 degrees of flexion

5. Primary arthrodesis of the DIP joint.

Discussion

The correct answer is (C)—early open repair of the avulsed profundus tendon. Profundus tendon avulsions are described by Leddy and Packer to be of three basic types. In type 1, the flexor tendon, which is avulsed, retracts into the palm at or proximal to the level of the A1 pulley. In type 2, the tendon is trapped at the level of the A3 pulley at the level of the PIP joint. In type 3, the tendon is usually retracted only minimally and usually lies at the level of the A4 pulley just proximal to the DIP joint. Other types include bony avulsions of the profundus tendon with a piece of the distal phalangeal base still attached to it. These usually tend to retract very minimally. In more complex types, the patient can also have avulsion of the tendon from the fragment of the bone that has also been avulsed, and in a more complex type, the distal phalangeal shaft itself can also fracture. The ideal time to repair these profundus avulsions is as soon as possible, and it appears that these are best done within the first week to 10 days. Thereafter, the musculotendinous unit undergoes a significant degree of myostatic shortening, and it may not be possible to restore the profundus tendon back to its attachment at the base of the distal phalanx, especially if the avulsion is a type 1.

Factors that adversely affect outcome of profundus avulsion include which of the following?

1. Type of avulsion

2. Time since injury

3. Presence of a bony fragment

4. Loss of vincular blood supply

5. All of the above

Discussion

The correct answer is (E). As mentioned above, outcomes are reported to be better in patients who undergo early repair, after which restoring the tendon to its attachment at the base of the distal phalanx can be extremely difficult. Furthermore, avulsions that retract to the level of the A1 or proximal to the A1 can do so only

after the vincule, which supplies the tendon, are ruptured. This does affect tendon vascularity and nourishment and may adversely affect tendon healing to site of attachment. Therefore, delayed presentations and type 1 ruptures can have poorer outcomes. Furthermore, bony avulsions are likely to have better outcomes if there is a single large bony fragment, which can be restored back into its bed at the base of the distal phalanx. This is because bony healing remains a lot more predictable, and stable bony healing and fixation can be achieved to allow early mobilization. In most circumstances with the soft tissue the avulsion of the tendon without any bony fragment the tendon has to be re-attached to the base of the distal philanx either with the help of a pullout suture which is tied over a button on the dorsal aspect of the nail plate or with the help of mini-suture anchors. Biomechanical studies have shown that suture anchor repair has the same mechanical strength as a pullout suture.

Which of the following are likely associated complications of this injury?

1. Stiffness of the PIP joint

2. Stiffness of the DIP joint

3. Instability of the DIP joint

4. Nail plate deformity

5. All of the above

Discussion

The correct answer is (E). Avulsions of the profundus tendon which retract to the level of the A3 pulley or even further proximally, can compromise pull through of the FDS tendon and thereby affect flexion and extension of the PIP joint as well. This may leave the patient not only with loss of DIP flexion but may also compromise PIP flexion from the scarred tendon in the flexor sheath. Stiffness of the DIP from lack of flexion also remains a distinct possibility. In some circumstances, these patients can develop delayed instability of the DIP joint from imbalance of an extensor which is able to extend the distal phalanx in the absence of a flexor which would normally flex the distal phalanx. This instability can be disabling, and in most circumstances, once the patient develops instability, DIP arthrodesis remains a solution. Finally, patients who undergo repair of the profundus tendon with the help of a pullout suture should be cautioned preoperatively about the possibility of a dystrophic nail. This can occur if the pullout suture passes through the germinal matrix, in which case the patient may develop a dystrophic nail (Fig. 4–4).

Objectives: Did you learn...?

Identify the clinical presentation of avulsion of the profundus tendon? Describe the factors that affect the outcome of profundus avulsion?

Understand the complications of these injury?