Carpal Injuries and Hand Arthritis


Chapter 18

Carpal Injuries and Hand Arthritis



Carpal Anatomy



1. The distal radioulnar joint (DRUJ) allows for supination and pronation of the hand.


2. The proximal carpal row consists of the scaphoid, lunate, triquetrum, and pisiform and allows for wrist extension, flexion, and radial/ulnar deviation.


• The proximal row articulates primarily with the distal radius through the scaphoid and lunate.


3. The distal carpal row consists of the trapezium, trapezoid, capitate, and hamate and forms the fixed unit of the hand along with the second and third metacarpals (see Figure 18.1).



4. The extrinsic carpal ligaments help to anchor the proximal row with the distal radius and ulna.


• The proximal row is anchored to the distal radius and ulna by the strong extrinsic palmar radiocarpal ligaments and the palmar portion of the triangular fibrocartilage complex (TFCC), as well as the dorsal intercarpal ligament (from scaphoid to triquetrum) and the dorsal radiocarpal ligament.


5. The intrinsic carpal ligaments are strong structures that link the carpal bones together, and/or the carpal rows together. The two most important intrinsic carpal ligaments are the scapholunate (SL) ligament and the lunotriquetral (LT) ligament. Disruptions of these ligaments lead to carpal instability.


• The SL ligament allows synchronous motion of the scaphoid and lunate


▪ It is U-shaped with a dorsal, proximal, and palmar component. The dorsal component is the strongest and most important for stability.


• The LT ligament anchors the lunate and triquetrum together and allows less motion than the SL ligament (see Figure 18.2).



6. The distal radius slopes 22 degrees in the radioulnar plane and 12 degrees in the dorsal/palmar plane.


7. The ulna should complete the smooth curve of the articular surface of the radius. The relationship of the ulna to this imaginary curve is called ulnar variance.


• Ulnar positive variance: The ulna extends distal to this imaginary curve.


▪ Associated with ulnar impaction syndrome (ulnar-sided wrist pain)


• Ulnar negative variance: The ulna is short of this imaginary curve.


▪ Associated with Kienböck’s disease (avascular necrosis of the lunate)


8. Gilula’s lines: Imaginary curves within the carpus that indicate normal extracarpal and intracarpal architecture (see Figure 18.3).


• Disruptions of these lines suggest ligamentous or bony carpal abnormalities.




Common Carpal Ligament Injuries



1. SL dissociation


• Results from an injury to, or tear of, the SL ligament or scaphoid fracture


• Characterized by pain and swelling over the radial dorsal wrist with widening of the gap between the scaphoid and lunate on plain X ray (“Terry Thomas” sign)


▪ Must compare with unaffected hand


▪ A gap >2 mm is suggestive of an injury.


• Disrupts the synchrony between the scaphoid and lunate, allowing the scaphoid to flex and lunate to extend


▪ As the scaphoid flexes, the cortex of the distal scaphoid pole projects as a ring on radiographs (“cortical ring sign”).


▪ On physical exam, a clunk can be palpated as the scaphoid is subluxed and relocated with radioulnar deviation of the wrist (“Watson scaphoid shift test”).


▪ A DISI (dorsal intercalated segment instability) deformity develops with SL injury as the lunate assumes a dorsally tilted posture and the scaphoid flexes. This can be identified on lateral X ray by an increased SL angle.


• Treatment options


▪ Immobilization for 3 to 4 weeks is generally acceptable for partial tears


▪ Open repair of the ligament is indicated with acute, complete tears or partial tears with persistent pain after immobilization.


▪ For chronic SL injuries, severe arthritis can develop, creating an SL advanced collapse (SLAC) wrist deformity.


○ Characterized by radioscaphoid, capitolunate, and scaphocapitate arthritis. In severe cases, the capitate can become impacted between the scaphoid and lunate.


○ Treatment: Proximal row corpectomy (removal of the scaphoid, lunate, and triquetrum) or “4-corner fusion” (removal of the scaphoid with fusion of the lunate, triquetrum, hamate, and capitate)


2. LT ligament injury


• Characterized by wrist swelling and pain, with a disruption in Gilula’s line from a step-off between the lunate and the triquetrum


• Disrupts the synchrony of the lunate and triquetrum, allowing the lunate to flex with the scaphoid


▪ On physical examination, pain and instability with “ballottement” or “shucking” of the lunate and triquetrum suggests injury.


▪ A VISI (volar intercalated segment instability) deformity develops as the lunate tilts volarly.


• Treatment options


▪ The ligament is often too short to repair primarily; thus, pinning of the LT interval is often performed, with or without ligament reconstruction.


3. Perilunate dislocation


• Caused by wrist hyperextension and supination with ligamentous injuries around the lunate, which progress from radial to ulnar


▪ When all of the ligaments are torn, the lunate can dislocate volarly into the carpal tunnel through the space of Poirer (“spilled tea cup sign” on lateral X ray).


• Characterized by a high-energy injury, with wrist swelling, pain, and potentially acute carpal-tunnel-syndrome symptoms


• Can also develop with scaphoid fracture and/or other carpal fractures (see Figures 18.4 and 18.5)




• Follows a natural progression of injury around the lunate complex


▪ Mayfield classification (see Figure 18.6)



• Treatment


▪ Closed reduction and splinting in the emergency room to relieve carpal tunnel symptoms (especially if no operating room is available)


▪ Urgent operative fixation and carpal tunnel release



Common Wrist/Carpal Fractures



1. Distal radius fracture


• The most common fracture of the human skeleton


• Often caused by a fall onto an outstretched hand


• Characterized by pain, swelling, limited motion, and gross deformity of the wrist


• Treatment options


▪ Cast immobilization is indicated for nondisplaced or minimally displaced fractures, especially in elderly patients.


▪ Open reduction internal fixation (ORIF)


○ General indications for ORIF: Displaced fractures, comminuted fractures, intra-articular fractures with displacement or >2 mm of cortical step-off, radial shortening >3 mm, and/or dorsal tilt >10 degrees.


○ Most commonly performed with volar locking plates


• Extensor pollicis longus (EPL) tendon rupture can occur after distal radius fracture.


▪ Secondary to attrition through disruption of tendon vascularity


▪ Treated with extensor indicis proprius tendon transfer


2. Scaphoid fracture


• The most common carpal fracture


• The scaphoid can be divided into three segments: Distal pole, waist, and proximal pole


▪ Single, dominant, vascular supply that enters the distal pole and travels retrograde to supply the proximal pole via the dorsal carpal branch of the radial artery


○ In addition, a minor secondary supply also enters distally via the superficial palmar branch of the radial artery.


○ This retrograde vascular supply portends a higher risk of nonunion or avascular necrosis with more proximal fractures.


• Scaphoid fractures are often caused by a fall onto an outstretched hand.


• Characterized by pain in the anatomic snuff box


• Fractures may not be visualized on initial plain radiographs


▪ Computed tomography (CT) is useful to evaluate for fracture in the acute period if concern for fracture is high and initial films are negative.


• Treatment options


▪ Long arm thumb spica cast immobilization for 6 to 8 weeks


○ Indicated for nondisplaced, distal pole fractures


○ For proximal pole fractures, immobilization is often recommended for 6 months.


▪ ORIF


○ Indicated in distal pole fractures displaced >1 mm, unstable transverse or oblique wrist fractures, and/or most proximal pole fractures.


○ Often performed with compression screw fixation (see Table 18.1)


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Sep 2, 2016 | Posted by in Aesthetic plastic surgery | Comments Off on Carpal Injuries and Hand Arthritis

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