53: Metacarpophalangeal and Proximal Interphalangeal Joint Collateral Ligament Avulsion Fractures

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Procedure 53 Metacarpophalangeal and Proximal Interphalangeal Joint Collateral Ligament Avulsion Fractures

Randy R. Bindra, Micah K. Sinclair

See Video 39: Metacarpal Shaft Fractures

Indications

Displaced collateral ligament with or without associated joint subluxation or dislocation

Large avulsion fragment with articular incongruity

Displaced and interposed fracture fragment within joint

Border digit injury such as radial border of index finger or ulnar collateral ligament of thumb metaphalangeal (MP) joint

Injury in athletes

Examination/Imaging

Imaging

Posteroanterior, oblique, and true lateral films of the digit for proximal interphalangeal (PIP) joint injuries. At the PIP joint, the most common avulsion fracture is a unicondylar fracture (Fig. 53-3).

Posteroanterior, oblique, and true lateral films of the hand for metacarpophalangeal (MCP) joint injuries (Fig. 53-4).

In the immature skeleton, ligament avulsion injuries occur at the growth plate with a fragment of the epiphysis (Fig. 53-5).

Brewerton view provides a tangential view of the metacarpal head, demonstrating the area of origin of the collateral ligament, which will help to reveal small avulsion fragments from the metacarpal head.

Computed tomography scanning is useful in cases of suspected involvement of the articular surface for evaluation of joint congruity.

FIGURE 53-3

FIGURE 53-4

FIGURE 53-5

Surgical Anatomy

MCP joint collateral ligaments are more commonly avulsed at their distal insertion. An avulsed fragment from the base of the proximal phalanx is lateral and volar to the midaxis.

Rarely, in more severe injuries, with pure ligamentous avulsions or smaller fragment avulsions, the avulsed ligament lies superficial to the extensor apparatus.

If avulsed without bone or with a small fragment, the ulnar collateral ligament of the thumb MP joint can come to lie superficial to the adductor aponeurosis (Stener lesion).

Positioning

The patient is positioned supine with the arm on a hand table.

The forearm is pronated, and the hand is placed on a towel roll. The surgeon is seated facing the injured side of the digit.

A tourniquet is used for the procedure.

Positioning Equipment

Intraoperative imaging is critical in this procedure. The mini C-arm is draped sterilely, placed at the axillary side of the table, and brought in when needed during the case.

Exposures

Metacarpophalangeal Joint

The MCP joint of the thumb and borders of the hand (ulnar side of small and radial side of index finger) can be easily accessed through a lateral approach.

Cutaneous nerves are located in the subcutaneous plane and must be identified and preserved.

The oblique fibers of the extensor hood cover the MCP joint and will need to be incised longitudinally for access to the joint; they require meticulous repair on completion.

Access to the MP collateral avulsion fracture for nonborder digits is achieved by a volar approach that allows reduction and fixation with compression.

With a volar approach, the digital neurovascular bundle is at risk for injury and must be identified and carefully retracted away from the flexor tendon sheath.

A Bruner zigzag skin incision is made centered over the proximal digital crease (Fig. 53-6).

The flexor sheath is kept intact (Fig. 53-7) and retracted subperiosteally off the base of the proximal phalanx and retracted (Fig. 53-8). After fracture fixation, the sheath is allowed to return to its normal position, and no repair is necessary.

FIGURE 53-6

FIGURE 53-7

FIGURE 53-8

Proximal Interphalangeal Joint

At the PIP level, the fracture is approached using a midaxial incision.

A digital midaxial incision is marked by joining the most dorsal points of the digital creases with the digit in full flexion (Fig. 53-9).

The transverse fibers of the extensor apparatus at the level of the PIP are released to elevate the lateral band of the extensor mechanism dorsally.

FIGURE 53-9

Pearls

The midaxial skin incision is dorsal to the midlateral line and avoids dissection of the digital neurovascular bundle.

Careful spreading dissection is necessary after skin incision to preserve the subcutaneous nerves.

When exposing the fragments, care must be taken to avoid stripping excessive soft tissue and devascularizing the fragment.

Pitfalls

Injury to cutaneous nerves.

Injury to the collateral ligament insertion on the fragment.

Injury to digital neurovascular bundle or flexor tendon sheath with volar approach to the MP joint.

Procedure

Step 1: Principles and Methods of Fixation

Type of fixation depends on size of fragment and comminution.

A single large fragment can be treated with lag screws. If possible, two screws should be employed for rotational stability.

Lag or compression screw implies a screw that does not have any purchase on the near fragment. This is achieved by drilling a glide hole that exceeds the screw thread diameter in the near cortex. The far cortex is then drilled with the thread hole that matches the screw shaft diameter. As the screw is inserted, it slides through the near cortex and gains purchase in the far cortex. With further tightening, compression between the fragments is generated (Fig. 53-10).

If screws are not available or lag screw fixation is not possible, tension band fixation of the fragment can be performed. Malleable wire is passed through the collateral ligament close to its bony insertion and passed through a drill hole in the metaphysis in a figure-of-eight loop. The fragment is then reduced, a K-wire is passed through the fragment for longitudinal stability, and the wire loop is tightened to compress the fracture.

If the fracture fragments are too small for fixation, they may be excised, and direct repair of the ligament to bone is performed using an anchor or pull-through sutures.

FIGURE 53-10

Step 1 Pearls

The screw head must be smaller than one third of the fragment width (Fig. 53-11).

It is preferable to use two small screws for better rotational stability and load distribution rather than a single large screw.

FIGURE 53-11

Step 1 Pitfalls

Using too large a screw can cause comminution of the fragment.

Overtightening the screw can fracture the near cortex.

Countersinking the screw head is not recommended in soft metaphyseal bone because it can result in excessive screw head penetration into the bone to cause loss of compression.

Step 2

The avulsed fragment is carefully handled to maintain the attached collateral ligament.

The fragment must be carefully retracted with a hook, and the joint is subluxated to look for any loose cartilaginous fragments or impaction of the joint surface (Fig. 53-12).

A 0.035-inch K-wire inserted into the fragment may be used as a joystick to gently manipulate the piece as needed (Fig. 53-13A).

After reduction, the same wire is advanced distally for temporary fixation (Fig. 53-13B).

The reduction is then checked by imaging.

Definitive fixation is then performed. If screw fixation is planned, the appropriate-sized glide hole is drilled through the fragment. The thread hole is then drilled through the far cortex. The screw length is determined, and an appropriate screw is inserted.

The K-wire is then removed, and the second screw is inserted through the K-wire hole, after overdrilling the near cortex (Fig. 53-14).

At the PIP joint, the screw head may interfere with gliding of the near collateral ligament. This can be avoided by placing one screw at or just proximal to the ligament origin. The second screw is placed between the main and accessory parts of the ligament and tightened until it sinks beneath the ligament complex (Fig. 53-15).

FIGURE 53-12

FIGURE 53-13

FIGURE 53-14

FIGURE 53-15

Step 2 Pearls

Ensure that reduction of the joint surface is anatomic before screw insertion.

Use the direction of the K-wire to guide screw placement.

When placing the second screw, apply a reduction forceps to hold reduction to avoid stripping the first screw when tightening the second.

Step 2 Pitfalls

The screw may accidentally penetrate the articular surface.

Placement of a long screw may cause irritation of the extensor mechanism at the base of the proximal phalanx.

A long screw at the head of the proximal phalanx may impinge on the collateral ligament at the far end of the joint and lead to joint stiffness.

Step 3

Screw length and position are checked by intraoperative imaging.

At the MCP joint, the flexor tendons with surrounding sheath are replaced, and no suture is necessary.

At the PIP joint, the extensor mechanism is then repaired with a continuous nonabsorbable suture.

The tourniquet is released to secure hemostasis.

Skin edges are approximated with sutures.

Postoperative Care and Expected Outcomes

The hand is rested in a plaster splint for the first 5 to 7 days after surgery.

The hand is placed in a removable splint, and active motion is commenced by the end of the first week after surgery. The ligament repair is protected by buddy taping to the digit adjacent to the injured ligament.

Splinting is discontinued by 4 to 6 weeks when tenderness and swelling have subsided.

Strengthening is commenced after full range of motion has returned.

Most patients with PIP joint injuries can expect residual swelling and flexion contracture that is usually mild.

MCP joint injuries have a better prognosis, and patients usually can regain full motion. Swelling around the joint is less noticeable than in the finger.

Pearls

Pain and edema control are essential in the immediate postoperative period.

Resting the hand with the MCP joint in flexion and PIP joint in full extension will prevent extension contracture of the joint.

Pitfalls

Aggressive motion in the face of pain and swelling in the immediate postoperative period will only exacerbate symptoms and cause loss of patient cooperation.

Bischoff R, Buechler U, De Roche R, Jupiter J. Clinical results of tension band fixation of avulsion fractures in the hand. J Hand Surg [Am]. 1994;19:1019-1026.

This case study included 100 patients from two surgeons at separate institutions with a variety of avulsion fractures in the hand: 51 bony mallet fractures, 38 bony gamekeeper’s fractures of the thumb, 8 fractures of the lateral phalange base, and 3 fractures of the dorsal aspect of the middle phalanx. Twenty-one of 51 bony mallet fractures had poor clinical and radiographic outcome. The remainder of the fractures included bony gamekeeper’s fractures, fractures of the lateral phalangeal base, and fractures of the dorsal aspect of the middle phalanx. All had excellent radiographic outcome, with only one nonunion, and excellent or satisfactory clinical result. (Level V evidence)

Kozin SH, Bishop AT. Tension wire fixation of avulsion fractures at the thumb metacarpophalangeal joint. J Hand Surg [Am]. 1994;19:1027-1031.

In this retrospective case series, nine patients underwent acute open reduction and tension wire fixation of displaced or rotated avulsion fractures. All healed with anatomic alignment without instability or articular incongruity. Mild pain, stiffness, and loss of pinch occurred in three of nine patients. MP motion averaged 77% of the respective opposite hand. IP motion, grip, pinch, and opposition were 96% to 99% that of the contralateral hand. (Level V evidence)

Schubiner JM, Mass DP. Operation for collateral ligament ruptures of the metacarpophalangeal joints of the fingers. J Bone Joint Surg [Br]. 1989;71:388-389.

This retrospective case series studied 10 patients who underwent operative fixation of MP collateral ligament rupture of a finger, most commonly the radial collateral ligament of the small finger. Joint instability with lack of end point with applied force was the operative indication. Operative fixation was performed at an average of 6 weeks after injury with pullout suture in 9 patients, and reconstruction with palmaris longus was used in 1 patient. All patients returned to preoperative level of function, free of pain and edema, by 3 months postoperatively. (Level V evidence)

Shewring DJ, Thomas RH. Avulsion fractures from the base of the proximal phalanges of the fingers. J Hand Surg [Br]. 2003;28:10-14.

Thirty-three patients had avulsion fractures from the base of the proximal phalanx due to abduction injury. Twelve percent to 28% of the joint surface was involved. Twenty-five patients underwent operative fixation with a single lag screw through the palmar approach. Immediate mobilization with full range of motion by 3 weeks was achieved. Eight patients initially chose nonoperative management and went on to nonunion clinically or radiographically by 2 months. All of these patients subsequently achieved union after operative fixation. (Level IV evidence)

Shewring DJ, Thomas RH. Collateral ligament avulsion fractures from the heads of the metacarpals of the fingers. J Hand Surg [Br]. 2006;31:537-541.

Nineteen patients with collateral ligament avulsion fractures from the metacarpal head were reviewed. Eleven patients with displaced fractures were treated with internal fixation through the dorsal approach within 5 days of injury. All went on to union. Seven of these regained full range of motion at 3 months, and 4 had persistent loss of flexion of the MP joint with arc of motion of 34 degrees. Seven patients with nondisplaced fractures were initially treated nonoperatively with buddy strapping. Of these, 4 achieved healing and full range of motion at 6 weeks. Three with nonunion underwent delayed operative fixation in the same fashion. All went on to union and full range of motion. (Level IV evidence)

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