A 40-year-old surgeon sustains a laceration of the flexor digitorum profundus tendon of the small finger in zone II. Operative repair includes use of a six-strand core with epitendinous sutures. Which of the following is the most effective program to achieve maximum active motion of the finger?

(A) Immediate free activity
(B) Immediate early active flexion
(C) Immediate passive flexion-active extension
(D) Late passive flexion-active extension
(E) Late active flexion

The correct response is Option B.

In patients with zone II flexor tendon injuries, outcome is most dependent on the repair technique and rehabilitation protocol used. Suture techniques that employ locking loops or multiple strands have been shown to be stronger and to provide a better, longer lasting repair than the standard, two-strand modified Kessler technique. Compliance is critical to successful rehabilitation. In general, an immediate, graded early active flexion program has been shown to result in greater total active motion than early passive flexion and/or late motion programs. Repair techniques that use increased strength, combined with a more detailed early, graded active flexion program, have been shown to optimize active flexion while minimizing tendon rupture. In addition, a history of smoking has been shown to correlate with poorer outcomes regardless of the method of rehabilitation.

References
1. Barrie KA, Tomak SL, Cholewicki J, et al. The role of multiple strands and locking sutures on gap formation of flexor tendon repairs during cyclical loading. J Hand Surg. 2000;25A:714-720.
2. Sandow MJ, McMahon MM. Single-cross grasp six-strand repair for acute flexor tenorrhaphy: modified Savage technique. In: Taras SJ, Schneider LH, eds. Atlas of the Hand Clinics. Philadelphia, Pa: WB Saunders Co; 1996:65-77.

A 30-year-old man has a flexion deformity of the left long finger eight weeks after sustaining a router injury to the finger. The flexor digitorum profundus tendon was repaired at the time of injury. On current examination, the patient has weakness of all fingers of the left hand and limited flexion of the ring and small fingers.

Which of the following is the most likely cause of the current findings?

(A) Adhesions of the flexor digitorum profundus tendon
(B) Lumbrical plus deformity
(C) Quadriga effect
(D) Rupture of the flexor digitorum profundus tendon
(E) Triggering of the flexor digitorum profundus tendon

The correct response is Option C.

This patient's deformity is most likely caused by the quadriga effect, which occurs as a result of excess distal pull on one profundus tendon. Because the flexor profundus tendons share a common muscle belly, any excess pull on one tendon will decrease the force and amplitude of all of the tendons. Quadriga can occur secondary to amputations in which the flexor digitorum profundus (FDP) tendon is attached to the extensor tendon or following grafting of excessively short tendons or advancement of the FDP tendon in patients with zone I injuries.

Flexor tendon adhesions can occur following injury or prolonged immobilization. Decreased flexion of the affected digit only is a characteristic finding.

Lumbrical plus deformity most frequently affects the index finger, which has an independent FDP tendon. Division of the distal tendon results in proximal migration of the tendon and lumbrical muscle, exacerbating tension on the lateral bands. This tension results in paradoxical extension of the proximal interphalangeal joint with attempted finger flexion.

A patient with a tendon rupture would be unable to flex the long finger; the other fingers would not be affected.

Triggering of the FDP tendon may be seen following tendon repair because of the excess bulk created as a result of the repair; this appears to interfere with the pulley system. Affected patients would have decreased motion of the long finger without any effect on the other fingers.

Reference
1. Bishop AT, Toper SR, Bettinger PK. Flexor mechanism reconstruction and rehabilitation. In: Peimer CA, ed. Surgery of the Hand and Upper Extremity. New York, NY: McGraw-Hill, Inc; 1996;2:1139.

A 35-year-old man has a 10-degree extensor lag at the proximal interphalangeal joint of the right index finger three months after undergoing flexor tendon repair in zone II. On examination, active motion of the finger is as follows:

Metacarpophalangeal joint - 80 degrees
Proximal interphalangeal joint - 60 degrees
Distal interphalangeal joint - 20 degrees

What is the total active range of motion of the index finger in this patient?

(A) 130 Degrees
(B) 140 Degrees
(C) 150 Degrees
(D) 160 Degrees
(E) 170 Degrees

The correct response is Option C.

The total active range of motion of the index finger in this patient is 150 degrees. Total active motion (TAM), which is used to measure range of motion of the fingers, is the sum total of active motion of the metacarpophalangeal (MP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints, subtracting any extension deficit of the joints. The range of motion of the MP joint (80 degrees), PIP joint (60 degrees), and DIP joint (20 degrees) is 160 degrees; the 10-degree extensor lag is then subtracted for a TAM of 150 degrees.

A person with normal TAM would have 90 degrees of motion in the MP joint, 110 degrees in the PIP joint, and 70 degrees in the DIP joint for a total of 270 degrees.

References
1. Chan SW, Jaglowski JM, Kaplan R. Rehabilitation of hand injuries. In: Cohen M, ed. Mastery of Plastic and Reconstructive Surgery. Boston, Mass: Little, Brown & Co; 1994;3:1745-1763.
2. Keeling CA. Range of motion measurement of the hand. In: Hunter JM, Mackin EJ, Callahan AD, eds. Rehabilitation of the Hand: Surgery and Therapy. Saint Louis, Mo: Mosby Ð Year Book, Inc; 1995;1:93-107.

A 17-year-old high school football player is unable to extend the proximal interphalangeal (PIP) joint of the ring finger two weeks after jamming the finger during a football game. Current physical examination shows hyperextension of the distal interphalangeal (DIP) joint with flexion of the PIP joint. There is full passive range of motion of the finger. Radiographs are unremarkable.

Which of the following is the most appropriate initial management?

(A) Extension splinting of the DIP joint
(B) Extension splinting of the PIP joint
(C) Extension splinting of the DIP and PIP joints
(D) Closed reduction and percutaneous pin fixation of the PIP joint
(E) Open repair of the central slip

The correct response is Option B.

This patient has a boutonniere deformity, which results from disruption of the central slip of the extensor tendon at the PIP joint with concomitant volar migration of the lateral bands. This volar migration may not be seen until 10 to 21 days after injury. Patients with boutonniere deformities have persistent flexion of the PIP joint resulting from loss of the central slip and the unopposed forces of the flexor digitorum superficialis tendon. The transverse retinacular ligaments become stretched, and the volarly migrated lateral bands exert direct pull on the DIP joint. This leads to the characteristic findings of hypertension of the DIP joint and worsening flexion of the PIP joint.

The most appropriate management is splinting of the PIP joint in extension; this can be performed successfully as late as six weeks after initial injury. The DIP joint should be left unencumbered to allow motion, which will result in dorsal migration of the lateral bands and reestablish the normal relationship of the tendinous structures within the finger.

References
1. Boyes JH, ed. Bunnell's Surgery of the Hand. 5th ed. Philadelphia, Pa: JB Lippincott Co; 1970:653.
2. Doyle JR. Extensor tendons - acute injuries. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;2:1950.