eMedicine Specialties > Plastic Surgery > Hand

Hand, Tendon Lacerations: Extensors: Treatment

Author: D Glynn Bolitho, MD, PhD, FACS, FRCSC, FCS(SA), Associate Clinical Professor, Department of Plastic Surgery, University of California at San Diego; Private Practice, LaJolla, California
Contributor Information and Disclosures

Updated: Oct 5, 2006

Treatment

Surgical Therapy

Injuries at specific levels

Distal interphalangeal joint (zone I)

Complete division of the terminal conjoined tendon beyond the insertion of the oblique retinacular ligaments results in the mallet finger deformity. With time, often an associated proximal interphalangeal volar plate relaxation with resultant swan neck deformity occurs (this mimics the swan neck deformity observed with volar plate rupture). As a general principle, any tendon imbalance tends to result in the opposite deformity in the uninvolved joint. This typically is observed in rheumatoid deformity.

• Open injury: These injuries are invariably intra-articular. Lavage and debridement of the joint, tendon repair, skin closure, and K wire fixation are the principles of management. A degree of hyperextension is desirable but avoid skin blanching. Remove the wire after 4 weeks and replace it with a mallet finger splint for 2 weeks. Introduce active flexion during the eighth week.
• Closed injury
  • Treat all these closed, with the single exception of those with an associated fracture involving a large intra-articular fragment (>30% of the articular surface). Accurate reduction of these large fragments is necessary. A pullout wire tied around a button on the volar pulp and a longitudinal C wire are used (or just the latter if the fixation is stable). In cases involving smaller fragments, percutaneous transarticular wire fixation avoids the need for open operation and both maintains the reduction and fixes the joint in extension.
  • In the routine closed injury without bony involvement, use a mallet finger splint, aiming for slight hyperextension. Take particular care to ensure that the dorsal skin is not blanched or jeopardized by local pressure consequent to the splint. Splintage alone produces the best results in closed injures, but it requires absolute patient compliance. The splint should be worn for 6 weeks. Introduce active extension after 8 weeks. If extensor lag is present after this time, reintroduce the splint.
• Established mallet finger deformity: Unopposed flexion of the distal interphalangeal joint results in stretching of the scar. Early scar contracts, thus a trial of splintage may be warranted in the first few months after injury. Surgical correction by excision of the redundant scar and prolonged splintage is best for those patients with established deformity. Verdan resected a segment of tendon more proximally. Failures are best treated by distal interphalangeal arthrodesis in 100º of flexion.
• Associated swan neck deformity: This is consequent to the combination of volar plate laxity at the proximal interphalangeal joint and imbalance of the extensor mechanism. It is best corrected by addressing the distal interphalangeal deformity. Alternately, a sliding tenotomy of the central tendon can be performed, taking great care not to produce a boutonnière deformity.
• Splinting techniques: Splintage must be applied constantly for a good result to be achieved. Proximal interphalangeal joint motion should not be restricted. K wire fixation causes little articular damage. Use a mallet finger splint for closed injuries.

Middle phalangeal level (zone II)

No clinical deformity is present since the oblique retinacular ligaments are preserved. Division of the conjoined tendon distal to the insertion of Landsmeer ligaments results in a mallet finger deformity. Repair and immobilize open injuries as for a mallet finger, with the exception that 4 weeks of immobilization is sufficient.

Proximal interphalangeal joint level (zone III)

Disruption of the central slip results in the boutonnière (ie, button hole) deformity. The head of the middle phalanx herniates through the extensor expansion. As the triangular ligament ruptures, the lateral bands displace volarly. Compensatory distal interphalangeal hyperflexion may be present. Closed injuries easily are missed, but the Carducci test is invaluable: with the wrist and metacarpophalangeal joints in partial flexion, the power of proximal interphalangeal extension is tested. An extensor lag of greater than 15° is diagnostic (flexion to diminish the contribution of the lateral bands to proximal interphalangeal extension).

• Open injury: Treat any laceration over the proximal interphalangeal joint as a central slip rupture until proven otherwise. These are best repaired with the proximal interphalangeal joint fixed in full extension. In contaminated wounds, repair is best delayed.
• Closed injury: Treat all closed injuries apart from those involving a large intra-articular bony fragment by splintage. Initial splintage is static or by K wire in uncooperative patients. Dislocation of the proximal interphalangeal joint usually is associated with disruption of the central slip. A bony fragment may be visible on radiographs and is an indication for operative intervention. However, patients usually present not with a boutonnière deformity but rather with diffuse swelling and limited range of motion due to periarticular soft tissue injury.
• Established boutonnière deformity: Patients who present with an established deformity are divided into 2 groups, those with mobile injuries and those with fixed injuries. In the latter group, establishing a full passive range of motion prior to the repair is essential. This may require surgical release of the contracted volar structures and passive stretching, or it may require merely the latter. However, obtaining a good result from surgery is difficult. Surgical options include the following:
  • Eaton and Littler technique - Incomplete transection of the lateral bands, allowing them to retract proximally and leaving the oblique retinacular ligament intact
  • Matev technique - One lateral band transferred to the base of the middle phalanx
  • Elliot technique - Anatomic repair of triangular ligament after reduction of the lateral band subluxation; shortening of the central slip by excision of elongated scar
  • Hayward technique
  The joint is fixed in all options by a transarticular wire. Retain the wire for 6 weeks, followed by external splintage for a variable period according to the extensor delay. External splintage usually requires a dynamic splint (eg, Capener splint, Joint jack, COSCO splint). Splintage is indicated for established deformities, following C wire removal in open injuries and after secondary repair, and as a preliminary trial in older patients.The Fowler procedure involves section of the conjoined tendon over the proximal section of the middle phalanx, with preservation of the oblique retinacular ligament. This is an option for symptomatic splinting failures (ie, those that fail to regain passive range of motion). Release of the oblique retinacular ligaments may be necessary if the distal interphalangeal joint cannot be flexed passively following repair, which is often more disfiguring than the boutonnière deformity. Alternately, operative failures can be addressed by arthrodesis, as necessary. The position of arthrodesis follows the normal digital cascade (30-90°). In rheumatoid arthritis, an interpositional arthroplasty is best.
• Swan neck deformity: The Littler oblique retinacular ligament technique for swan neck deformity relocates the one lateral band volarly and inserts it into the volar aspect of the middle phalanx. This functions to tighten as the proximal interphalangeal joint extends. Variations on the original Littler technique include the use of the palmaris longus in the "spiral oblique retinacular ligament" technique. The Littler flexor digitorum superficialis tenodesis routes the free proximal end of the flexor digitorum superficialis tendon through the volar aspect of the middle phalanx.

Proximal phalanx level (zone IV)

The injury may involve the central tendon, the lateral bands, or both. Unilateral division of a lateral band usually does not manifest as a deformity. Division of the central tendon manifests as a boutonnière deformity, but this is a rare occurrence. Division at this level usually involves an open wound. Treatment is by direct repair and K wire immobilization.

Metacarpophalangeal joint level (zone V)

The division of the extensor hood overlying the metacarpophalangeal joint results in an extensor lag. Active extension of the proximal phalanx against resistance is diminished. In the index or little fingers, this may not be evident if the proper tendon is intact (extensor digiti quinti, extensor indicis proprius).

The most common injury at this level is the "fight bite" due to human tooth injury. In these contaminated injuries, primary repair is contraindicated. Once the acute infection has been treated, the swelling has lessened, and the passive range of motion has been restored, repair can be undertaken. Splint the metacarpophalangeal joints in a full extension splint for 3 weeks. Of importance, the proximal interphalangeal and distal interphalangeal joints should remain free. Use a dynamic extension splint following removal of the splint until no extensor lag remains.

Metacarpal level (level VI)

The liberal juncturae tendineae tend to mask the underlying deformity. Repair all divided structures. A horizontal mattress suture is often better for these flat structures. If the tendon repair is likely to encounter the extensor retinaculum, dividing the latter is best. Splintage and immobilization are the same as in the former.

Division at the wrist joint (zone VII)

The extensor retinaculum is divided and repaired by Z lengthening. The tendons at this and more proximal levels resemble flexor tendons (ie, round) and should be sutured as such using a core suturing technique.

Thumb

Division of the extensor pollicis longus at the interphalangeal joint level results in a mallet deformity, while division at the metacarpal level only results in the inability to hyperextend the thumb. In the examination for extensor pollicis longus transection, passively extending the metacarpophalangeal joint is important to neutralize the intrinsic action on the interphalangeal joint. Also check for retropulsion of the thumb.

Division of the extensor pollicis brevis results in minimal deformity, or it may resemble a boutonnière deformity. In the latter, the action of extensor pollicis longus draws the interphalangeal joint into hyperextension, thus completing the deformity. The volar migration of the extensor pollicis longus tendon below the axis of rotation further compounds this deformity. In repairs to the extensor pollicis longus, supinating and adducting the first ray is important to take tension off the anastomosis. Transfix the involved joint with a K wire. Secondary repair is usually not possible after 4 weeks because of proximal retraction of the extensor pollicis longus. An extensor indicis proprius transfer is a better option.

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