7. Hand and Wrist MCQs

Kanavel's four cardinal signs of purulent flexor tenosynovitis are: 1) fusiform (sausage) swelling of the digit, 2) flexed resting posture, 3) exquisite tenderness along the course of the flexor tendon sheath, and 4) pain with PASSIVE extension. Pain on active extension is not a classical sign.

The clinical and radiographic presentation is classic for an enchondroma, the most common primary bone tumor of the hand. Standard definitive treatment involves allowing the fracture to heal (or treating concurrently depending on stability), followed by intralesional curettage and filling the defect with bone graft or a bone substitute.

For SLAC Stage II (arthritis between the scaphoid and radial styloid/scaphoid fossa), both proximal row carpectomy (PRC) and scaphoid excision with four-corner fusion (4CF) are surgical options. However, in a young, heavy manual laborer, 4CF is classically preferred over PRC because it generally preserves greater grip strength, whereas PRC carries a risk of progressive radiocapitate arthritis under heavy loading conditions.

The volar ulnar corner of the distal radius (volar lunate facet) is a critical keystone for carpal stability because the short radiolunate ligament attaches here. Standard volar locking plates often fail to capture this small, distal fragment. If it is missed or inadequately stabilized (often requiring fragment-specific fixation like a hook plate or wire), the lunate—and consequently the entire carpus—will subluxate or dislocate volarly.

A scaphoid nonunion involving the proximal pole complicated by avascular necrosis (AVN) is notoriously difficult to heal. In the absence of significant carpal collapse (e.g., SNAC wrist) or osteoarthritis, joint-preserving surgery is indicated. The best outcomes for achieving union in the setting of AVN are obtained with a vascularized bone graft (such as a 1,2-Intercompartmental supraretinacular artery [1,2-ICSRA] graft or a free medial femoral condyle vascularized graft) combined with rigid internal fixation.

The inability to actively flex the thumb IP joint after volar plating of a distal radius fracture is highly suggestive of flexor pollicis longus (FPL) tendon rupture. Placing the plate too distal (prominent at or distal to the watershed line) creates a mechanical block that leads to attrition and eventual rupture of the FPL tendon. Dorsal screw penetration would cause extensor tendon irritation or rupture (e.g., EPL), but EPL rupture results in a loss of thumb extension, not flexion. Injury to the recurrent motor branch affects the thenar muscles (opposition), not FPL (which is innervated by the AIN).

The patient has Kienböck's disease (avascular necrosis of the lunate) Lichtman stage IIIA (fragmentation of the lunate with normal carpal height) and negative ulnar variance. Joint-leveling procedures, such as a radial shortening osteotomy or ulnar lengthening, are indicated for Lichtman stages I, II, and IIIA with ulnar minus variance to mechanically unload the lunate and halt disease progression.

In a SLAC wrist, the pathology begins with scapholunate ligament disruption. The lunate, tethered to the radius via the strong short radiolunate ligament, remains concentrically reduced within the spherical lunate fossa. This unique congruent anatomical relationship protects the radiolunate joint from osteoarthritis, even in advanced (Stage III) SLAC wrists, allowing for salvage procedures such as proximal row carpectomy or four-corner arthrodesis.

The flexor pulley system consists of annular (A) and cruciate (C) pulleys. Biomechanically, the A2 pulley (located over the proximal aspect of the proximal phalanx) and the A4 pulley (located over the mid-portion of the middle phalanx) are the most critical. Loss of these major pulleys leads to significant bowstringing, causing a loss of active flexion and decreased mechanical efficiency (increased moment arm resulting in limited excursion).

The radiographs are classic for a Bennett's fracture, which involves a fracture of the palmar ulnar aspect of the proximal phalanx. This fracture fragment is still attached to the anterior oblique ligament. The deforming forces that cause subluxation of the base of the proximal phalanx include the pull of the abductor pollicis longus as well as the adductor pollicis. Adequate reduction can be achieved by closed reduction, percutaneous pin fixation, and casting. The fragment is too small for secure internal fixation. Stern PJ: Fractures of the metacarpals and phalanges, in Green DP, Hotchkiss RN, Pederson WC (eds): Green's Operative Hand Surgery, ed 4. Philadelphia, PA, 1999, pp 711-771.

Rupture of the central slip of the extensor mechanism and a varying degree of lateral band volar migration are the pathologic entities in an acute boutonniere injury. Splinting the proximal interphalangeal joint in full extension allows reapproximation of the central slip to the base of the middle phalanx. Distal interphalangeal joint flexion is permitted to allow movement of the lateral bands distally and dorsally, preventing contracture. Newport ML: Extensor tendon injuries in the hand. J Am Acad Orthop Surg 1997;5:59-66.

The diagnosis is squamous cell carcinoma. The radiograph shows a destructive lesion, and the histologic slides demonstrate squamous cells invading bone. The preferred treatment for squamous cell carcinoma is wide resection; however, in this location a wide margin can be achieved only with amputation. Overall survival in patients with squamous cell carcinoma secondary to chronic osteomyelitis is not significantly worse than that expected for age-matched controls. Dell PC: Hand, in Simon MA, Springfield D (eds): Surgery for Bone and Soft Tissue Tumors. Philadelphia, PA, Lippincott-Raven, 1998, pp 405-420.

The oblique radiograph of the wrist reveals a displaced fracture of the pisiform that usually occurs following a direct blow or sudden contraction of the flexor carpi ulnaris tendon. Persistent pain secondary to pisotriquetral incongruity and degenerative arthritis warrants pisiform excision, which does not compromise wrist flexion strength. Pisiform fractures are usually missed on routine radiographic views. An oblique or carpal tunnel view can be helpful in visualizing the pisotriquetral joint.

The arteriogram shows generalized disease of all vascular structures. Even though the image was obtained following an infusion of nitroglycerin, little flow is present to the fingers. Based on the history of soft-tissue calcifications and telangiectasia, the most likely diagnosis is CREST (chondrocalcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasias). The arteriogram reveals Raynaud's phenomenon or the "R" component of CREST. Buerger's disease, or thromboangiitis obliterans, is strongly associated with a history of smoking. Hypothenar hammer syndrome involves repetitive trauma to the ulnar artery at the wrist, resulting in well-defined filling defects in the superficial palmar arch of the hand. Although not well visualized in this patient, the superficial arch is narrowed, showing no evidence of aneurysmal dilation. Koman LA, Ruch DS, Patterson Smith B, et al: Vascular disorders, in Green DP, Hotchkiss RN, Pederson WC (eds): Green's Operative Hand Surgery, ed 4. New York, NY, Churchill Livingstone, 1999, vol 2, pp 2254-2302.

The PA view of the wrist shows a pisiform fracture. Pisiform fractures constitute 1% to 3% of all carpal bone fractures. This fracture can be further evaluated with a carpal tunnel view or a supination oblique view of the wrist. Initial management should consist of immobilization with a short arm cast. If nonsurgical measures fail, bony excision is warranted. Failla JM, Amadio PC: Recognition and treatment of uncommon carpal fractures. Hand Clin 1988;4:469-476.

The radiographs reveal a gap between the scaphoid and lunate bones, indicative of disruption of the scapholunate ligament complex. The three components of the complex are the dorsal scapholunate ligament, the volar (or palmar) scapholunate ligament, and the proximal fibrocartilaginous membrane, listed in decreasing yield strength. Disruption of the stout dorsal interosseous ligament is required for scapholunate dissociation to occur. Berger RA: The ligaments of the wrist: A current overview of anatomy with considerations of their potential functions. Hand Clin 1997;13:63-82.

The fracture of the proximal phalanx is clearly displaced. There is slight comminution at the area of the fracture. Closed reduction is likely to fail due to the forces of the extensor, flexor, and intrinsic mechanisms. Percutaneous fixation, unlike open fixation techniques, avoids likely problems with stiffness. Stern PJ: Fractures of the metacarpals and phalanges, in Green DP, Hotchkiss RN, Pederson WC, et al (eds): Green's Operative Hand Surgery, ed 5. Philadelphia, PA, Elsevier, 2005, p 281.

The clinical photographs and radiographs reveal a distal phalangeal amputation with soft-tissue coverage over nonexposed bone. This is an ideal circumstance to allow healing by secondary intention with wet-to-dry dressing changes. There are few complications and the aesthetics surpass that of any soft-tissue reconstruction procedure. Volar advancement flaps (Moberg flaps) are limited to small defects about the thumb. A thenar flap will provide good coverage; however, the results are not comparable to simple dressing changes. A V-Y flap is useful when there is more tissue loss dorsally. Jebson PL, Louis DS: Amputations, in Green DP, Hotchkiss RN, Pederson WC, et al (eds): Green's Operative Hand Surgery, ed 5. Philadelphia, PA, Elsevier, 2005, p 1947.

The palmar cutaneous branch of the median nerve separates from the median nerve approximately 4 to 6 cm proximal to the wrist crease and travels between the median nerve and the flexor carpi radialis tendon. It supplies the skin of the thenar region. This nerve is at risk for injury with retraction of the digital flexor tendons in plating the distal radius. Wartenberg's syndrome is compression of the superficial radial nerve which innervates the dorsum of the thumb and the first dorsal web space. Carpal tunnel syndrome causes dysesthesias of the thumb, index, and/or middle fingers. C7 radiculopathy affects the index and middle fingers. Jupiter JB, Fernandez DL, Toh CL, et al: Operative treatment of volar intra-articular fractures of the distal end of the radius. J Bone Joint Surg Am 1996;78:1817-1828.

The radiograph reveals oblique fractures of the third and fourth metacarpals. The rotational component of the fracture displacement is well visualized on the clinical photograph, which shows scissoring of the middle finger over the ring finger. The fracture obliquity results in rotational deformity that cannot be adequately maintained and held by closed treatment. The treatment of choice is open reduction and internal fixation. Stern PJ: Fractures of the metacarpals and phalanges, in Green DP, Hotchkiss RN, Pederson WC (eds): Green's Operative Hand Surgery, ed 4. Philadelphia, PA, 1999, pp 711-771. Freeland AE, Benoist LA, Melancon KP: Parallel miniature screw fixation of spiral and long oblique hand phalangeal fractures. Orthopedics 1994;17:199-200.