CASE                               10                               

A 14-year-old male was playing basketball and went up for a rebound. As he reached for the ball, he immediately developed pain in his ring finger and noticed a deformity. he was unable to generate any motion. Clinical appearance and a lateral radiograph taken in the emergency room are shown in Figure 4–9A and B.

Figure 4–9 A–B

The correct diagnosis is:

1. Dorsal dislocation of the PIP

2. Complex PIP dislocation

3. Rupture of the flexor digitorum superficialis

4. Rupture of the volar plate

5. None of the above

Discussion

The correct answer is (A). This patient has sustained a dorsal dislocation of his PIP joint. This injury is commonly associated with ball-associated sports, namely during blocking while playing volleyball, trying to catch a football, or while playing basketball during the act of either accepting a pass or rebounding. These are the most commonly described mechanisms, but this injury can also be sustained by other mechanisms, such as a fall. During the course of dorsal dislocation of the PIP, there is inevitably an injury to the volar plate as well as both collateral ligaments. The most common dislocation is in a dorsal direction with the base of the middle phalanx lying dorsal to the head of the proximal phalanx. In some circumstances,

there might be an angulatory displacement as well. Motion is usually limited secondary to the joint being dislocated as well as pain from the injury itself.

The most appropriate treatment at this time would be:

1. Closed reduction and percutaneous pin fixation

2. Open reduction and internal fixation

3. Closed reduction and assessment of stability

4. Open reduction and volar plate repair

Discussion

The correct answer is (C). In most circumstances, a simple closed dislocation of the PIP joint can be reduced closed. The stability of the joint is thereafter assessed, and again, in most circumstances, the joint is stable. It is not uncommon for the patient to be able to range the joint fully. The dislocation is best reduced closed in the emergency room. The finger is anesthetized with the help of a digital block. The MP joint is then flexed to relax the intrinsics, and with the combination of gentle traction on the fingertip as well as a milking maneuver over the dorsal aspect of the middle phalanx, it is possible to reduce the middle phalanx back into joint with the proximal phalanx. Thereafter, the patient is assessed in terms of stability and range of motion, and in most circumstances, it is possible to simply splint the patient with the joint slightly flexed for a couple of days to let the swelling and the pain settle down. Thereafter, with buddy taping to the neighboring digit, the patient may start a range of motion program. In some circumstances, the joint may be unstable at the extremes of extension. In these situations, the patient is splinted with the joint slightly flexed to about 15 to 20 degrees, and the finger is gradually straightened out to achieve full extension over the course of about 2 to 3 weeks.

The most common sequela from this injury includes which of the following?

1. Some soreness for a few months

2. Residual swelling for a few months

3. Residual stiffness for a few months

4. All of the above

Discussion

The correct answer is (D). Most simple closed dorsal dislocations of the PIP can be reduced closed, and patients start on a range of motion program, as mentioned above, within the first few days. In most circumstances, patients regain motion

within the first 3 weeks. However, it is not uncommon for some degree of soreness, swelling, and terminal stiffness to persist for several months. However, it has been noted that younger patients regain motion sooner and also do not have the same degree of residual stiffness and soreness as older patients. In addition to starting a range of motion program, it is beneficial to start the patient on an edema control program. This can be done by an experienced occupational therapist. In most circumstances, the range of motion program can be done unsupervised as a home exercise program.

The same patient could also present with a similar injury with an angulatory deformity, rotary deformity, and a lateral radiograph which does not confirm dorsal dislocation.

In this situation, the most likely diagnosis is:

1. Complex dislocation of the PIP joint

2. Rupture of only one collateral complex

3. Rupture of the volar plate

4. Rupture of the flexor digitorum superficialis

5. None of the above

Discussion

The correct answer is (A). Complex dislocation of the PIP joint usually involves buttonholing of the proximal phalanx head through the dorsal extensor mechanism. In such situations, the head of the condyle of the proximal phalanx usually buttonholes in the gap between the central tendon and the lateral band, and as a result, the head of the proximal phalanx is actually trapped in the noose formed by the central tendon and the lateral band. Attempts at reducing these with a combination of traction and corrective force can actually render the dislocation irreducible on account of tightening of the soft tissues around the buttonholed head of the proximal phalanx. Should simple, gentle manipulation not reduce these in the emergency room, most of these injuries require a formal open reduction. This is usually done through a dorsal approach, and the head of the proximal phalanx is immediately obvious as having buttonholed through the gap between the central tendon and lateral band. Gently elevating the lateral band allows prompt reduction of the proximal phalanx into the joint. These injuries thereafter require repair of the extensor mechanism and pinning of the joint provisionally for 2 to 3 weeks while the extensor mechanism heals. In most circumstances, these injuries in younger patients, as described in this situation, are likely to lead to very satisfactory

outcomes with near full range of motion.

Objectives: Did you learn...?

Describe the clinical and radiographic presentation of dislocation of the PIP joint? Treat PIP dislocation?

Identify sequela from this type of injury?