In-Service Exam
Hand - Tip - Amps - Dupuy - Vasc - 2002





A 3-year-old boy sustained a complete, clean amputation of the volar tip of the dominant small finger when he crushed the finger in a car door. On examination, there is a 1.0 * 0.9-cm defect of the volar fingertip; the distal phalanx is exposed. The amputated piece was recovered and brought to the emergency department.

Which of the following is the most appropriate management?

(A) Healing by secondary intention
(B) Split-thickness skin grafting
(C) Full-thickness skin grafting
(D) Composite grafting of the fingertip
(E) Reconstruction with a thenar flap

The correct response is Option D.

The most appropriate management in this 3-year-old child who has a minimal fingertip defect is replacement using the amputated tip as a composite graft. The results are often good in children who undergo composite grafting of modest fingertip defects because the amputated part typically survives completely.

Healing by secondary intention is appropriate for small defects without exposed bone, which may dessicate during the prolonged recovery period. Moist dressings can be used to cover the wound, but this becomes less optimal if the amputated tip is available for grafting. Split-thickness and full-thickness grafts should not be placed directly over exposed bone. A thenar flap is more appropriate for defects of the index and long fingers. In order to use this flap, the small finger must reach the thenar crease, which is difficult.

References
1. Leclercq C, Brunelli F. Treatment of fingertip amputations. In: Peimer, CA, ed. Surgery of the Hand and Upper Extremity. New York, NY: McGraw-Hill, Inc; 1996;1:1069-1100.
2. Williams CN Jr, Schenck RR. Fingernail and fingertip injuries. In: Cohen M, ed. Mastery of Plastic and Reconstructive Surgery. Boston, Mass: Little, Brown & Co; 1994;3:1493-1507.

In patients who sustain crush injuries to the fingers, significant nail bed lacerations are most closely associated with which of the following physical findings?

(A) Closed division of the extensor tendon (mallet finger)
(B) Dislocation of the distal interphalangeal joint
(C) Fracture of the distal phalanx
(D) Neurapraxia of the digital nerve
(E) Subungual hematoma involving 25% of the nail

The correct response is Option C.

Studies have shown that approximately 80% to 95% of patients with fractures of the distal phalanx have an associated nail bed laceration, making this the most commonly associated physical finding. In contrast, 60% of persons who have a subungual hematoma involving more than 50% of the nail have an associated nail bed laceration. These lacerations are seen more frequently in children and adolescents and are typically caused by crush injuries, in which the affected digit is caught in a door or window. The long finger is most often affected. In a patient who has either a fracture of the distal phalanx or a large subungual hematoma, the nail plate should be removed and the nail bed inspected under direct visualization. Nail bed lacerations can be repaired using small (6.0 or 7.0) absorbable sutures, which will prevent long-term nail ridging. The nail plate should then be replaced beneath the eponychial fold, where it will prevent the development of adhesions between the eponychial fold and nail matrix (termed "synechia").

Nail bed lacerations are not commonly associated with closed division of the extensor tendon or dislocation of the distal interphalangeal joint. Digital nerve neurapraxia is common in patients who sustain significant crush injuries to the fingertip but is not a predictor of nail bed lacerations.

References
1. Roser SE, Gellman H. Comparison of nail bed repair versus nail trephination for subungual hematomas in children. J Hand Surg. 1999;24A:1166-1170.
2. Simon RR, Wolgin M. Subungual hematoma: association with occult laceration requiring repair. Am J Emerg Med. 1987;5:302-304.

A 29-year-old computer programmer sustains an avulsion injury of the volar soft tissue of the dominant thumb to the level of the proximal nail. Examination shows exposed bone. When harvesting a Moberg advancement flap for coverage of the defect, which of the following should be included with the flap?

(A) One digital artery and one digital nerve
(B) One digital artery and two digital nerves
(C) Two digital arteries and one digital nerve
(D) Two digital arteries and two digital nerves
(E) Two digital nerves only

The correct response is Option D.

The thumb has a dual blood supply, which allows for harvest of volarly based flaps (such as the Moberg flap) without compromising digital perfusion. With the Moberg flap, volar tissue based on both neurovascular bundles is advanced. The edge of the defect comprises the distal limit of the flap. Lateral incisions are made between the dorsal and volar skin; the flap is dissected distally to proximally and raised from the remaining periosteum and flexor tendon sheath to include both digital arteries and digital nerves to the level of the metacarpophalangeal joint crease. Following harvest, the thumb joints are splinted in flexion for two to three weeks. Although pulp sensibility is near normal with the use of this flap, thumb stiffness may be seen. The typical Moberg flap can be advanced 1 to 1.5 cm. The skin at the base of the flap can be divided, and the subcutaneous tissue can be covered with a skin graft.

Larger defects can be reconstructed using either a neurovascular island flap from the index, long, or ring fingers or a free tissue transfer from the great toe.

References
1. Leclercq C, Brunelli F. Treatment of fingertip amputations. In: Peimer CA, ed. Surgery of the Hand and Upper Extremity. New York, NY: McGraw-Hill, Inc; 1996;1:1069-1099.
2. Lister GD, Pederson WC. Skin flaps. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:1783-1850.

A 32-year-old carpenter is scheduled to undergo a revision amputation procedure after sustaining an amputation of the left index finger at the level of the distal interphalangeal joint. She says that she often catches the finger on objects and has extension of the proximal interphalangeal (PIP) joint of the index finger when she attempts to make a fist.
Which of the following is the most likely cause of these findings?

(A) Adherence of the extensor tendon of the index finger
(B) Excessive power of the central slip over the flexor digitorum sublimis tendon
(C) Lumbrical plus deformity
(D) Quadriga effect
(E) Posttraumatic stiffness of the PIP joint

The correct response is Option C.

The findings in this patient are most likely caused by the development of a lumbrical plus deformity. Patients with this deformity have paradoxical extension of the proximal interphalangeal (PIP) joint during attempted flexion; the finger often catches on objects. Common causes of the lumbrical plus deformity include distal amputations, excessively long flexor digitorum profundus (FDP) tendon interposition grafts, and excessive FDP tendon lengthening procedures.
A patient with extrinsic extensor tendon adherence or scarring will have limited flexion across the metacarpophalangeal and PIP joints without paradoxical extension of the finger. The flexor digitorum sublimis tendon is still intact at the level of the distal interphalangeal joint. The quadriga effect results from adherence of the FDP tendon to the amputation stump. In patients with this condition, tethering of the FDP tendon in the injured finger leads to decreased motion and strength in the uninjured fingers. Posttraumatic stiffness would inhibit both passive and active range of motion of all joints in the hand.

References
1. Adamson GJ, Palmer RE. Amputations. In: Achauer BM, Erikson E, Guyuron B, et al, eds. Plastic Surgery: Indications, Operations, and Outcomes. Saint Louis, Mo: Mosby Ð Year Book, Inc; 2000;4:1831.
2. Sotereanos DG, Schmidt CC. Hand and digital amputations. In: Peimer CA, ed. Surgery of the Hand and Upper Extremity. New York, NY: McGraw-Hill, Inc; 1996;2:1001-1002.

A 27-year-old woman is scheduled to undergo coverage of a 3.0 * 1.5-cm full-thickness defect of the dominant right thumb using a neurovascular island flap from the ulnar aspect of the long finger. When harvesting this flap, which of the following structures is routinely divided?

(A) Radial digital artery of the long finger
(B) Radial digital artery of the ring finger
(C) Ulnar digital artery of the long finger
(D) Ulnar digital artery of the ring finger
(E) Ulnar digital nerve of the long finger

The correct response is Option B.

Because the radial digital artery of the ring finger is typically less important to finger perfusion, it is routinely ligated during mobilization of a neurovascular island flap from the ulnar aspect of the long finger. This flap, which is used in thumb reconstruction, derives its sensory innervation from the ulnar digital nerve. Although the flap can be harvested from the nontactile aspect of any digit, the ulnar aspect of the long finger is often used. Adequate blood flow in the ulnar digital artery of the ring finger and radial digital artery of the long finger must be ensured prior to flap harvest using either Doppler ultrasonography or an Allen's test. The ulnar digital artery and nerve of the long finger are included with the skin flap along with a cuff of fibrofatty tissue for venous drainage.

During dissection, the common digital arteries in the palm, which are branches of the superficial palmar arch, are identified first. The patency of the radial digital artery of the long finger and ulnar digital artery of the ring finger are confirmed, and the flap is harvested with the included structures identified above. The radial digital artery of the ring finger is divided. The proper ulnar digital nerve of the long finger may be dissected proximally from the common digital nerve to allow for tension-free transposition.

References
1. Lister GD, Pederson WC. Skin flaps. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:1783-1850.
2. Markley JM Jr, Littler JW. The composite neurovascular skin island graft in surgery of the hand. Atlas Hand Clin. 1998:59-76.

A 17-year-old boy is brought to the emergency department five hours after sustaining a complete amputation of the arm above the level of the elbow. Which of the following is the most appropriate initial management?

(A) Arterial shunting
(B) Bone fixation
(C) Fasciotomy
(D) Vein repair
(E) Revision amputation

The correct response is Option A.

The most appropriate first step in major limb replantation is establishment of blood flow. In any patient who sustains an amputation proximal to the level of the wrist, the blood supply must be reestablished within six hours of warm ischemia time (or 12 hours of cold ischemia time) to minimize the extent of myonecrosis. In a patient who seeks treatment immediately after sustaining an amputation, fasciotomies should be performed first, followed by bone fixation, arterial repair, vein repair, and then nerve repair. However, if the ischemia time is approaching the six-hour limit, temporary arterial shunting should be established with a Silastic endarterectomy shunt, small Foley catheter, or feeding tube. In patients who have prolonged ischemia, arterial flow should always be established before venous outflow. The arterial anastomosis should be opened to allow venous egress and to prevent the systemic return of lactic acid, which can result in detrimental complications.

References
1. Goldner RD, Nunley JA. Replantation proximal to the wrist. Hand Clin. 1992;8:413-415.
2. Idler RS, Steichen JB. Complications of replantation surgery. Hand Clin. 1992;8:427-451.

A 52-year-old man has a painless, nontender 2-cm mass in the left palm that has been stable for the past three years. He has a history of plantar fibromatosis but no history of trauma. His father and brothers have similar nodules. Which of the following is the most appropriate management?

(A) Observation
(B) Punch biopsy of the lesion
(C) Incisional biopsy of the lesion
(D) Excisional biopsy of the lesion
(E) Wide radical resection of the lesion

The correct response is Option A.

This 52-year-old man most likely has a Dupuytren's nodule; therefore, the most appropriate management is observation alone. Dupuytren's nodules are common in patients who have a history of plantar fibromatosis. Solitary nodules often remain unchanged for years, and only occasional follow-up examinations are required. Painful lesions can be treated with injection of a corticosteroid.

Because Dupuytren's nodules contain abundant myofibroblasts that produce abnormal collagen, purified collagenase has been used with some success in management. Other conservative treatments including application of dimethyl sulfoxide (DMSO), interferon therapy, splinting, and ultrasonography have not been proven to be widely effective.
Biopsy is not recommended for this nonmalignant lesion. Excision of a Dupuytren's nodule is rarely indicated.

References
1. Hurst LC, Badalamente MA. Nonoperative treatment of Dupuytren's disease. Hand Clin. 1999;15:97-107.
2. McGrouther DA. Dupuytren's contracture. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;1:563-591.
3. Rayan GM. Clinical presentation and types of Dupuytren's disease. Hand Clin. 1999;15:87-96.

A patient with Dupuytren's disease has flexion contractures involving the proximal interphalangeal joints of the right ring and small fingers. The most likely cause is involvement of which of the following cords?

(A) Central
(B) Lateral
(C) Natatory
(D) Pretendinous
(E) Spiral

The correct response is Option A.

This patient's flexion contractures are most likely caused by involvement of the central cord. The central cord has no precursor band; it arises with the pretendinous cord and attaches to the tendon sheath or bone of the middle phalanx. It is the most common cause of contractures involving the proximal interphalangeal (PIP) joint. Contracted cords are typically seen on one side of the finger only; diseased cords on both sides are rare.

The lateral and spiral cords can also cause flexion contractures of the PIP joint. In addition, the lateral cord can be a primary cause of flexion contractures of the distal interphalangeal joints. The spiral cords are composed of the spiral band, lateral digital sheath, and Grayson's ligament, which in the normal human hand form a spiral around the neurovascular bundle. However, in patients with Dupuytren's disease, the spiral cord contracts, causing the neurovascular bundle to form a spiral around the cord. Contraction of the spiral cord results in medial and superficial displacement of the neurovascular bundle.

The development of a natatory cord typically results in loss of finger abduction and flexion contractures of the PIP joints. Some fibers of the natatory cord may pass distally on the sides of the affected finger. The pretendinous cords cause contracture of the metacarpophalangeal joint. These cords evolve from the pretendinous bands; contracture of these bands causes pitting in the palm.

References
1. McFarlane RM. Dupuytren's disease. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;8:5061.
2. Zancolli E, ed. Structural and Dynamic Bases of Hand Surgery. 2nd ed. Philadelphia, Pa: JB Lippincott Co; 1979:19-20.

Which of the following best describes the flap used for thumb reconstruction shown in the photograph above?

(A) Based on the dorsal metacarpal artery to the ring finger
(B) Based on the posterior interosseous artery
(C) Supplied by a terminal branch of the median nerve
(D) Supplied by a terminal branch of the radial nerve
(E) Supplied by a terminal branch of the ulnar nerve

The correct response is Option E.

The photograph illustrates Littler's neurosensory island flap, which is based on the proper digital nerve to the ulnar aspect of the ring finger. This nerve is a terminal branch of the ulnar nerve. This flap is used to provide needed sensibility to the thumb and index finger pads. Its vascularity is supplied by the corresponding proper digital artery with venous return through multiple adventitial venae comitantes. The flap can be pedicled all the way to the superficial palmar arch by ligating the proper digital artery to the radial aspect of the small finger, creating a flap with adequate reach to resurface the volar aspect of the thumb. Adequate blood flow in the radial digital artery of the ring finger and ulnar digital artery of the small finger must be ensured prior to flap transfer. The common digital nerve to the fourth web space can be divided along the fascicles to allow for mobilization of the digital nerve to the level of the superficial arch.

This patient has third-degree burns of the thumb with destruction of the digital nerves resulting from an electrocution injury. In order to restore function and sensibility in the thumb, the neurosensory flap is elevated from the ulnar aspect of the ring finger, tunneled across the palm of the hand subcutaneously, and inset into the perimeter of the thumb wound to provide sensation to the thumb pad.

Flap vascularity is not supplied by the dorsal metacarpal artery or posterior interosseous artery. Nor do the radial and median nerves innervate the ulnar aspect of the ring finger, which would be transposed to provide sensation to the thumb pad.

References
1. Kleinman WB, Strickland JW. Thumb reconstruction. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:2103.
2. Strauch B, Vasconez LO, Hall-Findlay EJ, eds. Grabb's Encyclopedia of Flaps. 2nd ed. Philadelphia, Pa: Lippincott-Raven; 1998.

A 38-year-old man sustains a third-degree burn to the left hand. On examination, there is a 2 ( 2-cm area of exposed extensor pollicis longus tendon at the interphalangeal joint with destruction of the paratenon. Which of the following is most appropriate for coverage of the wound?

(A) Split-thickness skin graft
(B) Full-thickness skin graft
(C) Kite flap
(D) Moberg flap
(E) Thenar flap

The correct response is Option C.

The patient has a burn wound with exposed tendon (no paratenon) over a joint. Appropriate coverage will permit tendon glide and joint motion. Sensation is not required. The kite flap can be based on the first or second dorsal metacarpal artery over the dorsal aspect of the index and long fingers, respectively. The flap territory includes the dorsal skin of the proximal phalanx of the index finger for the first metacarpal artery flap and the dorsal skin of the proximal phalanx of the long finger for the second metacarpal artery flap. The radial and dorsal proximal interphalangeal sensory branches can be used to create a sensate flap. The first dorsal metacarpal artery flap works well when used for coverage of dorsal thumb wounds; however, the second dorsal metacarpal artery flap will not reach the dorsal thumb.

Coverage of this patient's wound with a skin graft will be unsuccessful. Neither a split- nor a full-thickness graft will heal over exposed tendon without paratenon, which will not provide adequate vascularization to support a skin graft. Additionally, the graft would adhere to the tendon.

A Moberg flap advances volar tissue from the thumb pad 1 to 1.5 cm for volar pad coverage. A thenar flap is appropriate for index and long fingertip pad defects. The thenar flap will not reach the interphalangeal joint area of the dorsal thumb.

References
1. Foucher G, Khouri RK. Digital reconstruction with island flaps. Clin Plast Surg. 1997;24:1-32.
2. Lister GD. Skin flaps. In: Green DP, ed. Operative Hand Surgery. 3rd ed. New York, NY: Churchill Livingstone, Inc; 1993;2:1741-1822.