Which of the following tendon transfers is most appropriate?

(A) Flexor carpi ulnaris to extensor carpi radialis brevis
(B) Flexor carpi ulnaris to flexor digitorum profundus
(C) Flexor digitorum profundus to extensor digitorum communis
(D) Flexor digitorum superficialis to flexor digitorum profundus
(E) Pronator teres to extensor carpi radialis longus

The correct response is Option D.

Patients with cerebral palsy typically have cognitive, developmental, and sensory deficits that affect motor function. Cerebral palsy can be characterized as spastic, with fluctuations in muscle tone, or as a motion disorder, involving ataxia, dyskinesia, and tremors. Although improvement is difficult to achieve in those affected by motion disorders, some children with spastic cerebral palsy have enhanced hand function following surgery.

Important elements included in the preoperative testing of patients with cerebral palsy are evaluation of cognition, hand placement, and sensibility. In patients who fail to meet the minimum criteria in these areas, the primary goal of surgery is improvement of hygiene and not necessarily of hand function.

Cognition is determined by intelligence quotient (IQ) testing; children can be classified as normal (within a standard deviation of the norm), educable (IQ of 50 to 70), and trainable (IQ of 30 to 50).

Hand placement is measured by asking the child to place one hand on the head initially and then on the opposite knee. This maneuver tests range of motion, precision of placement, and time required to complete the task. Typically, only those children who can perform this task within five seconds can be expected to benefit from surgery.

Sensibility testing varies according to the age of the child. Texture discrimination is the recommended test for children 2 to 3 years of age; object identification is appropriate for those from 4 to 5 years of age, and graphesthesia is tested in children ages 6 to 9 years. In children older than 9 years, sensibility is tested by measuring moving two-point discrimination. Functional improvement following surgery can only be expected in those children who can successfully discriminate texture, identify objects, or exhibit graphesthesia, or those who have moving two-point discrimination of less than 10 mm.

Because this 12-year-old boy with spastic cerebral palsy has both poor cognition and sensibility, improvement of hygiene will be the primary goal of any surgical procedure. Therefore, transfer of the flexor digitorum superficialis tendon to the flexor digitorum profundus tendon is recommended to eliminate the clenched fist deformity and relieve the maceration and disintegration of skin that is typically associated with this deformity. This tendon transfer lengthens yet weakens the finger flexors.

Transferring the flexor carpi ulnaris to the flexor digitorum profundus will only increase the flexion force and aggravate the deformity. Transfer of the flexor digitorum profundus to the extensor digitorum communis will not resolve the clenched fingers. In patients who have a deformity of this severity, arthrodesis of the wrist is recommended instead of tendon transfers to the wrist extensors.

References
1. Hoffer MM. Cerebral palsy. In: Green DP, ed. Operative Hand Surgery. 3rd ed. New York, NY: Churchill Livingstone, Inc; 1982:215-223.
2. Koman LA, Gelberman RH, Toby EB, et al. Cerebral palsy: management of the upper extremity. Clin Ortho. 1990;253:62-74.
3. Van Heest AE, House JH, Cariello C. Upper extremity surgical treatment of cerebral palsy. J Hand Surg. 1999;24:323-330.

An 18-year-old college student sustains an injury to the nondominant small finger when he falls while playing flag football. On physical examination, the finger is swollen slightly and held in a flexed position. Active flexion and extension of the finger are limited by pain. A radiograph is shown above. Closed reduction of the finger in the emergency department is unsuccessful.

The most likely cause is interposition of which of the following structures within the joint?

(A) Extensor tendon
(B) Flexor tendon
(C) Joint capsule
(D) Neurovascular bundle
(E) Volar plate

The correct response is Option A.

This 18-year-old college student has sustained a volar dislocation of the proximal interphalangeal (PIP) joint, an injury so named because the middle phalanx is dislocated volar to the proximal phalanx. In volar dislocations, which are far less common than dorsal dislocations, the extensor tendon is torn by the distal condyle of the proximal phalanx, as shown in the intraoperative photograph above. If the condyle has pushed through the extensor tendon, the tendon may tighten and act as a sling to prevent reduction of the dislocation.

Although some physicians may be able to perform closed reduction, operative exploration and repair are recommended because of the possible injury to the extensor tendon. Unsuccessful closed reduction is an absolute indication for operative exploration, as repeat attempts at manipulation will only worsen edema and may contribute to injury. In addition, volar dislocations can be associated with complete avulsion of the central slip, requiring repair.

Although the flexor tendons and volar plate can become interposed within the joint and interfere with closed reduction, this is a rare finding in patients with volar dislocations and is more likely to be associated with irreducible dorsal dislocations. The joint capsule and neurovascular bundle are not involved in volar dislocations of the PIP joint.

References
1. Concannon MJ, Hurov J, eds. Hand Pearls. Philadelphia, Pa: Hanley & Belfus; 2002;146-149.
2. Dray GJ, Eaton RG. Dislocations and ligament injuries in the digits. In: Green DP, ed. Operative Hand Surgery. 3rd ed. New York, NY: Churchill Livingstone, Inc; 1982:773-774.
3. Liss FE, Green SM. Capsular injuries of the proximal interphalangeal joint. Hand Clin. 1992;8:755-768.
4. Wang KC, Hsu KY, Shih CH. Irreducible volar rotatory dislocation of the proximal interphalangeal joint. Orthop Rev. 1994;23:886-888.

Repair of flexor tendon injuries in which of the following zones is most commonly associated with a good prognosis?

(A) Zone 1
(B) Zone 2
(C) Zone 3
(D) Zone 4
(E) Zone 5

The correct response is Option E.

Flexor tendon injuries in zone 5 have the best prognosis following repair. This zone, one of five in the flexor tendon system, lies proximal to the carpal tunnel. The generous space found proximal to the wrist allows for better tendon gliding following repair.

In contrast, zone 2 is an especially tight region that contains both flexor tendons within the fibro-osseous tunnel. There is an increased risk for development of adhesions when flexor tendons are repaired in this zone.

Repair of flexor tendon injuries in zones 1, 3, and 4 typically results in intermediate outcomes because of tendon vascularity and gliding potential in these zones.

References
1. Schneider LH. Flexor tendons – late reconstruction. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:1898-1949.
2. Strickland JW. Flexor tendons – acute injuries. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York NY: Churchill Livingstone, Inc; 1999;2:1851-1897.