Ryan J Grabow MDa Louis Catalano III MDb

Reverse Carpal Tunnel Syndrome

Natural Carpal Tunnel Syndrome Cures Systems

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aNevada Orthopedic & Spine Center, 2650 North Tenaya Way, Suite 301, Las Vegas, NV 89128, USA bC.V. Starr Hand Surgery Center, Saint Luke's-Roosevelt Hospital, 1000 Tenth Avenue, New York, NY 10019, USA

Carpal dislocations are rare injuries. They most often occur from high-energy trauma such as motor vehicle accidents, falls from a height, or industrial-related accidents. Usually occurring in young males in their twenties or thirties, these injuries may be missed initially because of concomitant injuries. A thorough understanding of the carpal anatomy, injury patterns, and treatment options is critical for proper management of these rare but significant injuries. In this article the authors address the five main categories of carpal dislocations, the associated anatomy, and their diagnosis, treatment, and prognosis.

Anatomy

Numerous studies have detailed the complex coordination of movement between the proximal and distal rows of the carpus, and the critical importance of the integrity of the intrinsic and extrinsic ligamentous system to maintain that coordination [1,2]. The extrinsic ligaments that link the radius and ulna to the carpus are divided into three major groups: volar radiocarpal, volar ulnocarpal, and dorsal radiocarpal ligaments.

Volar ligaments

The volar ligaments are the strongest of the extrinsic ligaments, and are the main stabilizers of the radiocarpal joint. There are four volar radiocarpal ligaments: radioscaphocapitate (RSC), long radiolunate (LRL), radioscapholunate (RSL), and short radiolunate (SRL) (Fig. 1). The first three originate from the lateral third of

* Corresponding author. E-mail address: [email protected] (R.J. Grabow).

the distal radius on its volar rim. The RSC is the most radial and runs obliquely across the volar waist of the scaphoid to insert on the capitate. It serves as a fulcrum for scaphoid flexion and is the primary restraint to ulnar translocation of the carpus. The LRL is ulnar to the RSC and is a strong tether to lunate displacement. The RSL ligament is felt to be a neurovascular conduit to the scapholunate (SL) ligament, and is not considered a stabilizing structure for the carpus [3]. The SRL ligament is the most ulnar of the radiocarpal ligaments arising from the volar ulnar lip of the distal radius. It travels vertically to insert on the lunate, providing a stabilizing force to prevent dorsal dislocation in hyperextension injuries [3]. The volar ulnar ligaments, which include the ulno-capitate (UC), the ulnotriquetral (UT), and the ul-nolunate (UL), link the carpus to the ulna. The UC ligament joins the RSC at the capitate, and together they form the arcuate ligament. Proximal to this point is a capsular weakening called the space of Poirier, through which the capitate or lunate dislocates in complex injuries. The midcarpal joint is stabilized volarly by the scaphotrapeziotra-pezoid (STT) ligament, the scaphocapitate (SC), and the triquetrohamatecapitate complex (THC). Also known as the ulnar leg of the distal V or arcuate ligament, the THC is a group of fan-shaped fibers that blend with the UC ligament.

Dorsal ligaments

The two primary dorsal extrinsic ligaments are the dorsal radiocarpal (DRC), also known as the dorsal radiotriquetral, and the dorsal intercarpal ligaments (DIC) (Fig. 2). The DRC extends from the dorsal edge of the radius, centered at Lister's tubercle, and inserts on the triquetrum to control ulnar translation. The DIC extends from the tri-quetrum to the dorsal distal scaphoid and dorsal

Scaphoid Anatomy
Fig. 1. Volar carpal ligaments. (From Berger RA. Ligament anatomy. In: Cooney WP, Linscheid RL, Dobyns JH, editors. The wrist: diagnosis and operative treatment. St. Louis (MO): Mosby; 1998; with permission.)

aspect of the trapezoid. It provides a dorsal support to translation of the midcarpal joint.

Intrinsic ligaments

The proximal carpal row is an intercalated segment consisting of the scaphoid, lunate, and triquetrum connected via stout interosseous ligaments (Fig. 3). There are no direct tendon insertions on the proximal row; thus the row's kinematics is dependent on the integrity of these ligaments. The SL ligament joins its respective bones and has three separate components: volar, dorsal, and proximal. The dorsal aspect is the

Dic Ligament
Fig. 2. Dorsal carpal ligaments. (From Berger RA. Ligament anatomy. In: Cooney WP, Linscheid RL, Dobyns JH, editors. The wrist: diagnosis and operative treatment. St. Louis (MO): Mosby; 1998; with permission.)
Intrinsic Carpal Ligaments
Fig. 3. Intrinsic carpal ligaments. (From Berger RA. Ligament anatomy. In: Cooney WP, Linscheid RL, Dobyns JH, editors. The wrist: diagnosis and operative treatment. St. Louis (MO): Mosby; 1998; with permission.)

strongest portion of the ligament and serves to resist excessive scaphoid flexion, translation, and intercarpal supination. The lunotriquetral (LT) ligament, joins the lunate and triquetrum, with its volar portion being the strongest. This ligament is vital to prevent ulnar translation of the triquetrum. The distal carpal row is linked via three primary ligaments: the trapeziotrapezoid (TT), the trapeziocapitate (TC), and the capitohamate (CH) ligaments.

Classification

Carpal dislocations can be divided into five separate groups: (1) perilunate dislocations, or lesser arc injuries; (2) transcarpal fracture-dislocations, or greater arc injuries; (3) radiocarpal dislocations; (4) axial dislocations; and (5) isolated carpal bone dislocations [4].

Diagnosis

Because of the significant force required to overcome the strong ligamentous support of the carpus, there is usually a history of significant high-energy trauma, such as a motor vehicle accident, fall from a height, or industrial accident. In the acute setting, there is obvious pain and swelling of the hand and wrist. Gross deformity of the wrist is usually noted. Often a firm tender mass is noted over dislocated carpal bones. A step-off or void may be noted in the proximal row if swelling is not yet significant. Most often, deep palpation of the wrist will be intolerable for the patient, and is usually not necessary for diagnosis. On examination the patient may have symptoms of median or ulnar nerve compression caused by swelling or direct impingement by displaced carpal bones. As for all trauma about the wrist, standard posteroanterior (PA) and lateral radiographs should be obtained. Oblique images of the carpus, such as the 45° pronated or supinated views, can give further information and are often helpful in recognition of injuries at the carpometacarpal (CMC) joints. Additionally, PA and lateral views with the carpus in traction can be of great value in defining the full extent of the injury [5]. Advanced imaging with CT or MRI can give further information about the status of the ligamen-tous injury or fracture pattern when necessary.

Perilunate dislocations

Perilunate dislocations are the most common of the carpal dislocations. Usually occurring in young men in the second or third decade of life, these injuries are the result of wrist hyperextension, often caused by a fall from a height, a motor vehicle accident, or contact sports. The limits of ligamen-tous and bony constraints are exceeded with palmar tension and dorsal compressive forces of wrist hyperextension. A variety of injury patterns can occur with this mechanism, depending on the position of the extremity at impact, the quality of the bone, the ligamentous strength, and the direction of force [6]. These injuries are rarely seen in the older population, because without good bone quality the distal radius is most likely to fail before the carpal bones or ligaments. In the pediatric population, the hyperextension forces required to cause these injuries usually injure the weaker radial physis rather the carpal ligaments.

Often perilunate dislocations are associated with other concomitant injuries of the bones or soft tissues of the carpus. Carpal fractures or fractures of the radial or ulnar styloid occur more often than purely ligamentous perilunate dislocations. Approximately two thirds of carpal dislocations involve a fracture through the middle third of the scaphoid, with trans-scaphoid perilu-nate dislocation being the most common injury encountered in all published series [5]. Additionally, a fracture of the capitate is also frequently encountered, present in approximately 8% of all fracture dislocations of the wrist.

Pathomechanics

The concept of a sequential pattern of inter-carpal wrist instability was supported by the work of Mayfield and colleagues [6], and resulted in the understanding of perilunate instability as a spectrum of injury they termed ''progressive perilunar instability." Divided into four stages, this pattern of injury was reproducible in the laboratory with hyperextension, ulnar deviation, and intercarpal supination of the wrist with an applied axial load. Based on the viscoelastic properties of bones and ligaments, the rate of loading determines the pattern of injury, with slower loading resulting in carpal fractures, and faster loading resulting in ligamentous injury [7].

Classification

Perilunate dislocations are classified based on the bones and joints involved, the direction of displacement, and the degree of rotation of the lunate. Johnson [8] defined pure ligamentous injuries without fracture as ''lesser-arc'' injuries, and fracture dislocations involving one or more of the carpal bones surrounding the lunate as ''greater-arc'' injuries (Fig. 4). Most commonly the scaphoid is fractured; however, the radial and ulnar styloids, capitate, and triquetrum can also be involved. Lunate alignment was classified by Witvoet and Allieu [9] based on the degree of angulation. Normal alignment (Grade I), rotated palmarly less than 90° (Grade II), rotated greater than 90° but still attached by the palmar ligaments to the radius (Grade III), and total enucleation without any soft tissue connections (Grade IV). Although these other classifications are useful to describe fracture patterns and ligamentous disruption, the classification by Mayfield and colleagues [6] is the most commonly used classification system (Fig. 5). The stages of perilunar instability are described as follows.

Stage I: scapholunate dissociation

With forceful distal carpal row extension, supination, and ulnar deviation, the STT and SL ligaments are under tension, resulting in an extension force transmitted to the scaphoid. The scaphoid extends, causing the SL ligament to transmit torque to the lunate. Because of the palmarly located long and short radiolunate ligaments and the UL ligament, the lunate is restricted in its ability to extend, and resists the torque transmitted via the SL ligament. If the extension force to the scaphoid persists, either the scaphoid waist will fracture or the SL ligament will tear from volar to dorsal, eventually resulting in a complete dissociation of the ligament. With this differential extension between the scaphoid and lunate, the space of Poirier is opened.

Lunate Lesser Arc

Fig. 4. Greater and lesser arc injuries. Lesser arc injuries are purely ligamentous, whereas greater arc injuries are ligamentous disruptions with associated fractures of the radius, ulna, or adjacent carpal bones. (From Tolo ET, Shin AY. Fracture dislocations of the carpus. In: Trumble TE, editor. Hand surgery update 3. Rosemont (IL): ASSH; 2003; with permission.)

Fig. 4. Greater and lesser arc injuries. Lesser arc injuries are purely ligamentous, whereas greater arc injuries are ligamentous disruptions with associated fractures of the radius, ulna, or adjacent carpal bones. (From Tolo ET, Shin AY. Fracture dislocations of the carpus. In: Trumble TE, editor. Hand surgery update 3. Rosemont (IL): ASSH; 2003; with permission.)

Kienb Swanson

Fig. 5. Progressive perilunate instability. Schematic representation of the four stages of perilunate instability, viewed from the ulnar side. Stage I: As the distal carpal row is forced into hyperextension (black arrows), the scapho-trapezio-capitate ligaments (1) pull the scaphoid into extension, thus opening the space of Poirier (asterisk). The lunate cannot extend as much as the scaphoid, because it is directly constrained by the short RL ligament (2). When the SL torque reaches a certain value, the SL ligaments may fail, usually from palmar to dorsal. A complete SLD is defined by the rupture of the dorsal SL ligament (3). Stage II: Once dissociated from the lunate, the scaphoid-distal row complex may dislocate dorsally relative to the lunate (black arrow). The limit of such dorsal translation is determined by the RSC ligament (4). Stage III: If hyperextension persists, the ulnar limb of the arcuate ligament (5) may pull the triquetrum into an abnormal extension, thus causing failure of the lunotriquetral ligaments (6). Stage IV: Finally, the capitate may be forced by the still intact RSC ligament (4) to edge into the radiocarpal space and push the lunate palmarward until it dislocates into the carpal canal in a rotatory fashion. All white arrows represent the distraction forces occurring in the ligaments. (From Garcia-Elias M, Geissler WB. Carpal instability. In: Green DP, Hotchkiss RN, Pederson WC, et al, editors. Operative hand surgery. 5th edition. Philadelphia: Elsevier; 2005. Modified from Mayfield JK, Johnson RP, Kil-coyne RK. Carpal dislocations: pathomechanics and progressive perilunar instability. J Hand Surg [Am] 1980;5:2226-41; with permission.)

Fig. 5. Progressive perilunate instability. Schematic representation of the four stages of perilunate instability, viewed from the ulnar side. Stage I: As the distal carpal row is forced into hyperextension (black arrows), the scapho-trapezio-capitate ligaments (1) pull the scaphoid into extension, thus opening the space of Poirier (asterisk). The lunate cannot extend as much as the scaphoid, because it is directly constrained by the short RL ligament (2). When the SL torque reaches a certain value, the SL ligaments may fail, usually from palmar to dorsal. A complete SLD is defined by the rupture of the dorsal SL ligament (3). Stage II: Once dissociated from the lunate, the scaphoid-distal row complex may dislocate dorsally relative to the lunate (black arrow). The limit of such dorsal translation is determined by the RSC ligament (4). Stage III: If hyperextension persists, the ulnar limb of the arcuate ligament (5) may pull the triquetrum into an abnormal extension, thus causing failure of the lunotriquetral ligaments (6). Stage IV: Finally, the capitate may be forced by the still intact RSC ligament (4) to edge into the radiocarpal space and push the lunate palmarward until it dislocates into the carpal canal in a rotatory fashion. All white arrows represent the distraction forces occurring in the ligaments. (From Garcia-Elias M, Geissler WB. Carpal instability. In: Green DP, Hotchkiss RN, Pederson WC, et al, editors. Operative hand surgery. 5th edition. Philadelphia: Elsevier; 2005. Modified from Mayfield JK, Johnson RP, Kil-coyne RK. Carpal dislocations: pathomechanics and progressive perilunar instability. J Hand Surg [Am] 1980;5:2226-41; with permission.)

Stage II: lunocapitate dislocation

As the extension-supination moment continues, the scaphoid-distal row complex is forced into further extension, subsequently leading to a dorsal dislocation of the capitate relative to the lunate over the intact distal edge of the DIC ligament. The capitate is limited in its dorsal displacement by an intact RSC ligament. The entire distal row and the dissociated radial portion of the proximal row follow the capitate dorsally, further opening the space of Poirier.

Stage III: lunotriquetral disruption

After the capitate has dislocated, further extension-supination torque and a dorsal translation vector is transmitted to the triquetrum through the ulnar limb of the arcuate UC ligament. As the triquetrum extends, this torque is transmitted to the LT ligament. If the extension torque continues, a tear of the LT ligament or triquetrum avulsion fracture may result. Usually the LT tear progresses from volar to dorsal. With complete rupture of the LT ligament, the ulnar expansions of the LRL ligament usually also tear, leaving the SRL ligament and the UL ligament as the lunate's only stabilizing forces.

Stage IV: lunate dislocation

If the extension force continues, the dorsally displaced capitate may be pulled proximally and volarly into the radiocarpal space by a still-intact RSC ligament, muscle contraction, or external force. The DRC ligament is disrupted and the capitate pushes the lunate volarly, causing it to hinge on the intact palmar ligaments and displace volarly into the carpal tunnel. Thus, lunate dislocation is the end stage of a dorsal perilunate dislocation.

Diagnosis

Despite continued efforts to educate emergency providers, 16% to 25% of perilunate injuries are initially missed on examination in the emergency department and present late as chronic dislocations [5,10]. A late presentation leads to a significantly poorer outcome and often necessitates a salvage operation. Therefore it is critical for these injuries to be identified acutely. On examination, the patient will have a swollen, tender wrist and pain with minimal range of motion. The neurovascular examination may reveal symptoms of median nerve compression caused by swelling or impingement of the lunate on the carpal tunnel in Stage III and IV dislocations. Standard PA and lateral radiographs may reveal several characteristic findings: (1) foreshortened carpus and loss of carpal height; (2) "triangular-shaped" lunate overlapping the capitate; (3) scaphoid flexion, exhibiting a "ring sign''; (4) a break in Gilula's line proximally between the lunate and triquetrum; (5) prominent dorsal pole of the lunate as it tips into palmar flexion; (6) lunate lying palmar to the radius; and (7) capitate in palmar flexion (Fig. 6).

Treatment

As for any carpal dislocation, the goal of treatment is anatomic reduction of the carpus. In the acute setting treatment should always include closed reduction and immobilization to reduce pressure on the surrounding structures. If closed reduction achieves an anatomic reduction, percutaneous pinning can be combined with immobilization to stabilize the wrist. This was previously the recommended treatment [6]; however, recent literature has shown a high rate of recurrent instability, carpal incongruity, and arthritis. For most injuries, better results have been achieved with open reduction, ligament repair, and internal fixation than with closed methods, and open reduction is now the current standard of care [4-6].

Closed reduction

The technique for closed reduction of a perilu-nate (Stage I-III) or lunate (Stage IV) dislocation has been described by several authors [11,12]. An essential component is complete muscle relaxation, either through general anesthesia, or Bier's or axillary block. The wrist is then suspended in

Spilled Teacup Sign

Fig. 6. Injury radiographs: (A) AP radiograph with foreshortened carpus and "triangular-appearing" lunate suggesting abnormal carpal alignment. (B) Lateral radiograph clearly shows palmar flexion of lunate, "spilled teacup'' sign, flexion of scaphoid, and capitate collinear with radial shaft in this Stage IV perilunate dislocation, "a volar lunate dislocation."

Fig. 6. Injury radiographs: (A) AP radiograph with foreshortened carpus and "triangular-appearing" lunate suggesting abnormal carpal alignment. (B) Lateral radiograph clearly shows palmar flexion of lunate, "spilled teacup'' sign, flexion of scaphoid, and capitate collinear with radial shaft in this Stage IV perilunate dislocation, "a volar lunate dislocation."

finger traps with approximately 10 lbs traction for at least 10 minutes to relax muscular spasm. Fluoroscopic assessment of the wrist in traction can be very helpful in assessing the full extent of the injury. After sufficient suspension in traction, the volar distal aspect of the wrist is palpated with the dominant thumb until clearly pressing distally and dorsally on the lunate. While maintaining thumb pressure on the lunate, the finger traps are removed. The wrist is then extended, while the thumb continues to stabilize the lunate. Longitudinal traction is applied manually, and the wrist is slowly flexed while pressing volarly on the lunate. During this maneuver the capitate is brought into flexion and usually reduces onto the lunate with a palpable snap. Maintaining dor-sally directed pressure on the lunate during this maneuver is critical to avoid pushing the lunate further volarly. After the capitate has been reduced onto the lunate, the lunate is pushed dor-sally while maintaining traction and slowly extending the wrist. The lunate will usually reduce during this maneuver, and full reduction will be achieved (Figs. 7, 8). Fluoroscopy is then used to confirm reduction of the radiolunate and capi-tolunate joints. The wrist is splinted in neutral position, allowing for motion at the metacarpo-phalangeal (MCP) joints and digits to help reduce digital swelling and stiffness. Splinting in maximal flexion is not required, and may lead to acute carpal tunnel syndrome. In certain circumstances,

Lunate Dislocation Closed Reduction

Fig. 7. Perilunate/lunate dislocation closed reduction technique. (A) After 10 minutes of uninterrupted traction, and following fluoroscopic traction views of the wrist, the surgeon supports the patient's hand as the finger traps are removed. The wrist is extended and the surgeon places his thumb over the proximal palmar projection of the lunate (X). (B) While maintaining manual longitudinal traction and applying pressure against the palmar projection of the lunate, the wrist is gradually flexed and the capitolunate reduction is felt as a distinct snap (arrow). (From Taleisnik J. The wrist. New York: Churchill Livingston; 1985; with permission)

Fig. 7. Perilunate/lunate dislocation closed reduction technique. (A) After 10 minutes of uninterrupted traction, and following fluoroscopic traction views of the wrist, the surgeon supports the patient's hand as the finger traps are removed. The wrist is extended and the surgeon places his thumb over the proximal palmar projection of the lunate (X). (B) While maintaining manual longitudinal traction and applying pressure against the palmar projection of the lunate, the wrist is gradually flexed and the capitolunate reduction is felt as a distinct snap (arrow). (From Taleisnik J. The wrist. New York: Churchill Livingston; 1985; with permission)

attempts at closed reduction will be ineffective and open reduction will be required. Because of the possible compression of the median nerve caused by a palmarly dislocated lunate, emergent open reduction and subsequent fixation combined

Lunate Dislocation Tavernier

Fig. 8. Schematic representation of the capitolunate reduction based on the original description by Tavernier. (1) With the wrist slightly extended, gentle manual traction is applied. (2) Without releasing traction, and while the lunate is stabilized palmarly by the surgeon's thumb, the wrist is flexed until a snap occurs. This indicates that the proximal pole of the capitate has overcome the dorsal lip of the lunate. (3) Traction is then released and the wrist is brought back into neutral. (From Garcia-Elias M, Geissler WB. Carpal instability. In Green DP, Hotchkiss RN, Pederson WC, et al, editors. Operative hand surgery. 5th edition. Philadelphia: Elsevier; 2005; with permission.)

Fig. 8. Schematic representation of the capitolunate reduction based on the original description by Tavernier. (1) With the wrist slightly extended, gentle manual traction is applied. (2) Without releasing traction, and while the lunate is stabilized palmarly by the surgeon's thumb, the wrist is flexed until a snap occurs. This indicates that the proximal pole of the capitate has overcome the dorsal lip of the lunate. (3) Traction is then released and the wrist is brought back into neutral. (From Garcia-Elias M, Geissler WB. Carpal instability. In Green DP, Hotchkiss RN, Pederson WC, et al, editors. Operative hand surgery. 5th edition. Philadelphia: Elsevier; 2005; with permission.)

with a carpal tunnel release should be considered if any signs of median nerve compression arise.

Open reduction and repair

Despite the general understanding that surgery provides the best opportunity for a successful outcome, there is still some debate upon the surgical exposure for these injuries. Success has been reported with a dorsal or volar exposure; however, each approach is somewhat limited in providing full access to these carpal injuries. In a multicenter study, Herzberg and colleagues [5] reported that a failure to identify and treat each component of the injury was a major determinant of an unsatisfactory result, and that open reduction and internal fixation achieved better radiographic and clinical results. A combined dorsal-volar approach provides full visualization of the ligamentous and osseous injuries, and enables one to address every aspect of the injury pattern. First reported by Dobyns and Swanson in 1973 [11], the utility of the dual incision approach enables the surgeon to achieve a good outcome. This has been well-supported in the literature, and should most often be employed for injuries Stage II or greater [4,13-15].

Reduction of the lunate to the radius, reduction of the scaphoid, triquetrum, and capitate to the lunate, stabilizing the reduction with pinning, and subsequent ligament and capsule repair are the necessary steps in treating these complex injuries. Associated styloid or carpal fractures are treated appropriately with either internal fixation or pinning, with bone grafting applied as necessary. In Stage III and IV injuries there is a consistent volar capsular rent that must be repaired. Additionally, the carpal tunnel should be released and the wrist immobilized after surgery. Despite early and anatomic reduction, most patients lose some degree of grip strength and motion, and also develop radiographic signs of arthritis and carpal collapse after these injuries; however, these clinical measurements and radiographic changes do not directly correlate with patient satisfaction or ability to return to work, especially when the carpal injury is an isolated problem [16].

Technique

Volarly, an extended carpal tunnel approach is used with care to identify and protect the palmar cutaneous nerve. The flexor tendons are retracted and the median nerve is inspected. With the nerve and flexor tendons retracted, the volar capsule is inspected. A transverse rent is consistently found within the volar capsule, extending from radial to ulnar. Most often this rent is proximal to the capitate, at the space of Poirier, between the RSC and LRL ligaments. If the lunate was not reduced, its distal articular surface can be visualized through this rent. The lunate is reduced by manually pushing it dorsally back between the capitate and radius. This is facilitated by manual longitudinal traction on the hand. The capsular rent is then repaired deep to its synovial covering with 3-0 nonabsorbable sutures (Fig. 9). It is important to note that the easily visualized portion of the rent is only its synovial covering, and that the important volar ligaments are deeper structures below this synovial layer and must be included as part of the repair. Special attention should be paid to the corners of the rent, to ensure

Extended Carpal Tunnel Approach

Fig. 9. Palmar approach—open reduction of dorsal perilunate-palmar lunate dislocation. (A) A proximally extended carpal tunnel incision is used. Care must be taken to avoid injury of the palmar cutaneous branch of the median nerve. (B) Once the flexor tendons are retracted radially, the palmar radiocarpal capsule is inspected. Usually a transverse rent coinciding with the space of Poirier, and across the palmar lunotriquetral ligaments, is found, whether the lunate is displaced into the carpal tunnel or not. (C) While an assistant applies longitudinal traction to the hand, the lunate is reduced. (D) The transverse derangement is repaired with nonabsorbable sutures. (From Garcia-Elias M. Carpal instability. In: Green DP, Hotchkiss RN, Pederson WC, et al, editors. Operative hand surgery. 5th edition. Philadelphia: Elsevier; 2005; with permission.)

Fig. 9. Palmar approach—open reduction of dorsal perilunate-palmar lunate dislocation. (A) A proximally extended carpal tunnel incision is used. Care must be taken to avoid injury of the palmar cutaneous branch of the median nerve. (B) Once the flexor tendons are retracted radially, the palmar radiocarpal capsule is inspected. Usually a transverse rent coinciding with the space of Poirier, and across the palmar lunotriquetral ligaments, is found, whether the lunate is displaced into the carpal tunnel or not. (C) While an assistant applies longitudinal traction to the hand, the lunate is reduced. (D) The transverse derangement is repaired with nonabsorbable sutures. (From Garcia-Elias M. Carpal instability. In: Green DP, Hotchkiss RN, Pederson WC, et al, editors. Operative hand surgery. 5th edition. Philadelphia: Elsevier; 2005; with permission.)

that the ulnar LT and the radial RSC ligaments are included in the repair (Fig. 10).

After the volar rent has been repaired, a dorsal longitudinal incision is created over Lister's tubercle. The dissection continues between the third and fourth compartments. Silk sutures are placed in the retinacular flaps to aid in retraction. The fourth compartment is reflected ulnarly with its tendon sheath intact. The capsule is usually distended and filled with blood if it has not already been disrupted. Splitting the dorsal capsule in line with the fibers of the DRC, from the radius to the triquetrum and then to the capitate, allows for adequate visualization of the joint and a strong capsular repair during closure. The joint is thoroughly irrigated to remove any cartilaginous or osseous fragments. The full extent of injury is then assessed. Most often the SL ligament is avulsed from the lunate, and the LT ligament is avulsed from the triquetrum. The articular surfaces of the scaphoid, lunate, capitate, and radius are then inspected and documented, because full-thickness cartilage injuries are frequently found (Fig. 11).

A well-aligned lunate is the foundation upon which the carpus is then repaired. The lunate is reduced using a 0.062 Kirschner wire (K-wire) ''joystick'' placed halfway through the lunate from dorsal to volar. Once the lunate reduction has been confirmed under intraoperative fluoros-copy, it is stabilized with a temporary 0.062 K-wire from the radius to the lunate. The SL joint is then reduced by placing a joystick 0.062 K-wire in the scaphoid and correcting its orientation with the lunate. After the reduction is confirmed under fluoroscopy, the SL joint is stabilized using 0.045 K-wires; one or two wires from the scaphoid into the lunate, and another from the scaphoid into the capitate. These wires are safely placed using a 2 cm longitudinal incision over the anatomic snuffbox, just distal to the radial styloid to avoid injury to the radial artery and superficial radial nerve. A temporary joystick K-wire is then placed in the triquetrum to aid in reduction of the LT joint, and the joint is stabilized with a percutaneous 0.045 K-wire from the triquetrum to the lunate. Depending on surgeon preference, the lunocapitate (LC) joint can be further stabilized with two 0.045 K-wires from the capitate into the lunate. These wires can be placed retrograde through the capitate before reduction of the LC joint to facilitate their placement. Once the carpus is confirmed radiographically to be anatomically reduced and stabilized, the SL and LT ligaments are repaired using minisuture anchors (Fig. 12). At times the SL and LT ligaments are extensively damaged and primary repair is limited. In these cases, every attempt is made to repair the ligaments, and tacking them in place with suture anchors is acceptable and can still provide a good result. If there is not enough tissue remaining of the SL or LT ligaments, a primary stabilization procedure as described by Brunelli and Brunelli [17] or Linscheid and Dobyns [12] may be considered if repair is not possible.

Associated fractures of the carpal bones or radial styloid should be addressed before final joint reduction and fixation. Use of K-wires or screw fixation is equally acceptable and is based on surgeon preference. One should avoid excision of radial styloid fracture fragments because these fragments represent the attachment of the volar radiocarpal ligaments. Removal of these fragments may lead to radiocarpal instability postoperatively.

To ensure anatomic reduction, final radiographs should be obtained before closing the incisions. The wrist should be protected postoper-atively in a short arm cast. Pins are usually removed at 8 to 10 weeks, followed by occupational therapy for range of motion and strengthening. A return to

Scottish Rite Hospital Dallas Map
Fig. 10. (A) Volar capsular rent. (B) Capsular rent repaired with 3-0 nonabsorbable sutures. (Courtesy of Peter Carter, MD, Texas Scottish Rite Hospital, Dallas, TX.)
Pictures Kienbock Disease

Fig. 11. Interosseous ligament avulsions. (A) Intraoperative inspection of the wrist usually reveals an avulsion of the SL ligament from the lunate. This is repaired with a minisuture anchor or bone tunnels. (B) Inspection of the LT ligament reveals avulsion of the LT ligament off the lunate, although it is more commonly found to have been avulsed from the triquetrum. C, capitate.

Fig. 11. Interosseous ligament avulsions. (A) Intraoperative inspection of the wrist usually reveals an avulsion of the SL ligament from the lunate. This is repaired with a minisuture anchor or bone tunnels. (B) Inspection of the LT ligament reveals avulsion of the LT ligament off the lunate, although it is more commonly found to have been avulsed from the triquetrum. C, capitate.

full activities of daily living is possible at 3 months, with sports and heavy labor restricted for at least 4 to 6 months. Because of the significant energy absorbed by the wrist in these injuries, some heavy laborers may have difficulty returning to full heavy activities until 1 year postoperatively.

Late presentation of perilunate dislocations

Occasionally patients may present well after the acute phase of their injury. The injury can be

Perilunate Dislocation Post Fixation

Fig. 12. (A,B) Intraoperative fixation of perilunate dislocation. AP and lateral radiographs of reduction and fixation of the carpal dislocation encountered in Fig. 6. Suture anchors were used to repair the SL and LT ligaments to the lunate. A K-wire from the radius to the lunate was used for temporary intraoperative fixation and was removed before closure.

Fig. 12. (A,B) Intraoperative fixation of perilunate dislocation. AP and lateral radiographs of reduction and fixation of the carpal dislocation encountered in Fig. 6. Suture anchors were used to repair the SL and LT ligaments to the lunate. A K-wire from the radius to the lunate was used for temporary intraoperative fixation and was removed before closure.

missed acutely because of multiple other injuries or altered mental status. In this regard, chronic or late lunate dislocation is defined as greater than 6 weeks after injury [18]. Because of the length of time since injury, the surgeon is faced with the difficulty of addressing contracted soft tissues, cartilage loss, and possible carpal avascular necrosis. Although an attempt at closed reduction is warranted, it is most often unsuccessful and should only be attempted in the operating room with complete relaxation of the extremity and a clear operative plan if the location is unable to be reduced. A host of treatment options have been described, including open reduction and internal fixation, lunate excision, proximal row carpec-tomy, and wrist arthrodesis. Siegert and colleagues [10] reported on a series of 15 patients (10 dislocations, 5 fracture dislocations) who had delayed treatment. Six patients underwent open reduction internal fixation and all had satisfactory outcomes. Proximal row carpectomy and wrist arthrodesis were each performed in 2 patients, with all 4 patients obtaining acceptable results. Lunate excision alone was not found to be successful. The study authors found that open reduction, internal fixation (ORIF) is the procedure of choice unless faced with severe cartilage damage. If the repair fails, a salvage procedure can then be used.

Complications

Because of the amount of energy needed for carpal dislocations, significant injury to the bones, ligaments, and surrounding structures can result in complications despite optimal management. Stiffness, complex regional pain syndrome, lunate avascular changes, tendon rupture, and recurrence of instability have all been reported complications.

In one multicenter study [5], 56% of patients were found to have post-traumatic arthritis of the radiocarpal and midcarpal joints at an average of 6 years follow-up. Lunate changes with increased radiodensity may be noted during the first months after reduction; however, Kienbock's disease and lunate collapse are rare, with only a few cases reported in the literature [19].

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