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Open and Arthroscopic Treatment of Perilunate Injuries

Weil, Wayne, M*; Slade, Joseph, F, III; Trumble, Thomas, E*

Section Editor(s): Meals, Roy A MD, Guest Editor; Harness, Neil G MD, Guest Editor

Clinical Orthopaedics and Related Research: April 2006 - Volume 445 - Issue - p 120-132
doi: 10.1097/01.blo.0000205889.11824.03
SECTION I: SYMPOSIUM: Problem Fractures of the Hand and Wrist
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Carpal dislocations are rare and complex injuries. Nearly every combination of radiocarpal and intercarpal dislocation has been described, but few fit neatly into a particular pattern or classification scheme. The injury may be subtle clinically and radiographically, and the diagnosis is frequently delayed. Prompt recognition, accurate reduction, and stable temporary internal fixation all contribute to improved outcomes. Internal fixation techniques depend on the pathology imparted on the carpus. Open reduction, arthroscopic, and fluoroscopically aided percutaneous techniques can be used to successfully treat carpal dislocations. We report our experiences treating perilunate injuries.

Level of Evidence: Level V (expert opinion). See the Guidelines for Authors for a complete description of levels of evidence.

*From the Division of Hand and Microvascular Surgery, Department of Orthopaedic Surgery, University of Washington Medical Center, Seattle, Washington; and the †Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut.

Each author certifies that he has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. Each author certifies that his or her institution has approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research, and that informed consent was obtained.

Correspondence to: Thomas Trumble, MD, Professor and Chief, Division of Hand and Microvascular Surgery, Department of Orthopaedic Surgery, University of Washington Medical Center, Box 356500, Seattle, WA 98195-6500. Phone: 206-543-3690; Fax: 206-685-3139; E-mail: trumble@u.washington.edu.

The complex intercarpal relationships provide a tremendous amount of wrist mobility in both flexion/extension and radial/ulnar deviation. Disruptions of these relationships are rare and complex injuries. Nearly every combination of radiocarpal and intercarpal dislocation has been described, but few fit neatly into a particular pattern or classification scheme. The injury may be subtle clinically and radiographically, and the diagnosis is frequently delayed. Prompt recognition, accurate reduction, and stable temporary internal fixation all contribute to improved outcomes.

Because the lunate is strongly bound to the radius and ulna by the volar capsular ligaments, in severe injuries the lunate often remains reduced to the distal radius while the remainder of the carpus is dislocated. These injuries are commonly referred to as perilunate dislocations. Lunate dislocation occurs when the lunate rotates volarly on these strong capsular ligaments and the remainder of the carpus and hand remains relatively aligned with the distal radius and ulna. Other patterns of carpal dislocations include the transscaphoid perilunate fracture dislocation, transcaphoid transcapitate perilunate dislocation, and the transcaphoid transhamate perilunate dislocation and injuries associated with fractures of the distal radius.

We present a treatment algorithm for the variety of injuries that encompass the spectrum of perilunate fracture dislocations. These techniques include using open and arthroscopic approaches to treat these complex injuries. The outcomes of these treatment techniques are reviewed as well.

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Historical Perspective

Perilunate dislocations are a broad continuum of injuries ranging from minor ligament strains to complete dislocation of the lunate. Perilunate dislocations are generally associated with carpal instabilities.38,39 The earliest information on perilunate dislocations was published in 1926 by Etienne Destot.14 In the 1920s closed reduction was proposed as a treatment option as more case reports of lunate dislocations were reported. In 1923, Davis discussed Gunn's law, which has become an established orthopaedic principle of recreating the deformity prior to reversal of the mechanism of injury. There has been a wealth of literature and information that has aided our understanding of the anatomy and surgical management of perilunate dislocations and associated fractures.7,12-14,23,25,29,33,37-41,43,48,50,52-54,58,59,61,62,66,70

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Anatomy

The ligaments of the wrist can be divided into the intracapsular ligaments (including the interosseous ligaments), the scapholunate interosseous ligaments (SLIL)and lunotriquetral interosseous ligaments (LTIL), the radio-scapholunate ligament, the palmar capsular ligaments, and the dorsal capsular ligaments. The intraosseous ligaments have a unique anatomy that allows the carpal bones to rotate with respect to one another without allowing significant translation or gapping. The SLIL is one of the most important ligaments stabilizing the carpus.7,38,39,42 It is divided to three zones: the dorsal, membranous, and palmar. The dorsal segment is the strongest and may be the most important in the causation of certain instability patterns.5 The radiocapitate ligament and raiotriquetral ligament are the palmar capsular ligaments that form two V shaped patterns with a space between the two Vs that have less ligament support. The space of Poirer and the lunate can dislocate through this space in perilunate fracture/dislocations (Fig 1). The radioscaphocapitate (RCS) is an important secondary stabilizer to the carpus.69 The radioscapholunate (RSL), or the ligament of Testut, was initially considered a key stabilizer of the carpus.6,8 However, anatomic studies have demonstrated that this is a vestigial embryonic structure that served as a vascular pedicle in the fetus.9,10,31 The dorsal ligaments are thinner and weaker, but they play an important role in the final stages of carpal instability when static deformity occurs.6 The dorsal intercarpal (DIC) appears to have the most significant role in controlling carpal motion (Fig 2).17,62,64,67

Fig 1

Fig 1

Fig 2

Fig 2

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Pathomechanics

Carpal dislocations typically result from high energy injuries in young men. Motor vehicle accidents, falls from a height, and sports accidents are the most common causes of injury. The mechanism of injury is typically hyperextension and ulnar deviation.35 The injury patterns can be from direct or indirect mechanisms. The direct mechanism involves energy being dissipated to the dislocating bone. It can be focal and cause a discrete fracture dislocation, or diffuse and cause a more global dislocation. Indirect mechanisms are deforming forces applied from a distance from the injured joint and typically, common to the traumatic events causing dorsal perilunate dislocations. When the point of rotation is distal to the radius there is more stress on the carpal bones and this results in a carpal fracture dislocation.23,41 Proximal contact and force dissipation at the distal radius results in distal radius fractures.

Mayfield et al41 described progressive perilunate instability where the four stages of progressive ligamentous damage occur with the wrist hyperextended, and with variable degrees of ulnar deviation and forearm supination. Cadaver specimens were tested with sudden loading to produce carpal dislocations. There was a predictable pattern of injury as the SLIL was torn followed by a sequence of ligaments around the lunate in an ulnar direction until dislocation of the carpus occurred with or without a fracture of one of the carpal bones.41

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Diagnostic Imaging

Standard plain radiographs including posteroanterior and lateral radiographs will show a perilunate injury, but additional views give the necessary information to appreciate subtle carpal fractures.35 Tomograms, nuclear scans, and three-dimensional scanning are not particularly helpful in evaluating carpal dislocations, but may aid in localizing more subtle area of injury such as osteochondral fractures.

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Diagnosis

Perilunate injuries may appear subtle clinically and radiographically, and diagnosis is often delayed. The largest review of perilunate dislocations and fracture dislocations reported the diagnosis was initially missed in 25% of patients, even in isolated trauma.26 Not surprisingly, treatment becomes more difficult and outcome is adversely affected by delay.

Clinically, pain and swelling are common, but deformity may be mild. Signs of median nerve injury may be present, and dysesthesia without motor dysfunction occurred in 16% of patients in one large series.2 Plain posterior-anterior (PA) and lateral radiographs of the wrist are almost always sufficient for diagnosis, but findings are sometimes subtle. On PA radiographs the space between individual carpal bones should be uniform. Uneven gapping between the carpal bones indicates disruption of their ligamentous connections. Gapping of greater than 2 mm of the scapholunate space are indicative of SLIL injuries. The articular surfaces of proximal and distal carpal rows should form smooth arcs at the radiocarpal and midcarpal articulations. Disruption of these lines is indicative of carpal instability or injury.22 With perilunate dislocation these arcs are disrupted and unusual overlap of adjacent bones is seen. The “scaphoid ring sign” is indicative of SLIL injury as the scaphoid rotates to become more perpendicular to the radius. On PA radiographs the double-density of the scaphoid distal pole and tubercle overlying the proximal pole of the scaphoid creates the “ring sign”. On the lateral radiographs, there is always considerable overlap of the carpal bones. This can be confusing, but the distinctive moon shape of the lunate can be identified with careful inspection. The radius, lunate, and capitate should be relatively collinear. The proximal convex surface of the lunate should be seated on the distal radius, and the head of the capitate should be seated in the concavity of the distal lunate. In perilunate dislocations, the lunate-capitate articulation is disrupted, and the concave distal lunate no longer articulates with the capitate. These injuries always disrupt the scapholunate interosseous ligament, and may be complicated by rotary subluxation of the scaphoid even after successful reduction.41 The scapholunate angle should measure between 30°-60° on lateral radiographs. With rotatory subluxation the lunate tends to dorsiflex as the distal scaphoid palmarflexes, which causes this angle to increase.

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Classification

There are multiple classifications for carpal instability patterns and carpal fracture/dislocations that help describe this complex injury pattern.23,39,41 These classifications systems serve to guide treatment algorithms by describing the progressive nature of these complex injuries. Knowledge of the pathophysiology of the injury patterns allows treatment to proceed in a logical stepwise fashion. We believe that the classification scheme described by May-field et al,38,39,41 is useful in the context of describing the anatomic basis of the injury pattern and therefore guides the surgeon in the reconstructive effort.

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Treatment

Carpal dislocations usually occur in young people with high energy injuries. A full musculoskeletal examination and screening for concomitant axial or appendicular skeletal injuries are very important. Median nerve injuries can occur by direct blow as a contusion or by increase carpal canal pressures secondary to hemorrhage. Adkison and Chapman2 identified nine patients with median nerve dysfunction in their series of acute perilunate injuries. Eight of the nine patients had resolution of their symptoms with reduction of the carpus.1 However, one patient had persistent dysesthesias and recovered only after late carpal tunnel release.1 Patients with median nerve deficit immediately after injury have probably sustained an acute contusion of the median nerve and probably do not require immediate nerve decompression. However, the patient with delayed onset of median nerve symptoms should have decompression of the carpal tunnel.16 This serves to decrease the pressure in the carpal canal caused by soft tissue swelling and hematoma formation.

The definitive treatment of these complex injuries is operative.11,16,19,25,27,28,36,45,49,55,60,61,65,68 Adkison and Chapman1 reviewed a large number of acute perilunate injuries. They found that loss of reduction occurred in (59%) of 32 wrists where initial anatomic closed reduction was achieved with casting.1 Apergis et al4 compared the outcome of eight perilunate injuries treated with closed reduction and casting to 20 patients treated with open reduction and internal fixation (ORIF). The clinical outcome was fair or poor in all patients treated with casting alone, while 65% of patients treated with ORIF had good or excellent results.3 Apergis et al3 stated that these injuries were too unstable to be treated without fixation.

Nearly all dislocations that occur within the capitate displace dorsally.38,39,41 The carpus should be reduced as soon as possible by extending the wrist to recreate the deformity and applying dorsal pressure to reduce the capitate into the lunate fossa. Open reduction and repair of the SLIL and lunotriquetral ligaments must be performed. Immediate closed reduction is recommended. If this is successful surgery for open reduction fixation can be delayed three or four days when the swelling has subsided. If the fracture cannot be reduced surgery must be performed immediately.

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Perilunate Dislocations

We use a standard dorsal longitudinal approach for perilunate dislocations. The extensor retinaculum is identified, the third dorsal compartment released, and the extensor pollicus longus (EPL) tendon is retracted radially. The fourth dorsal compartment is sharply elevated off the capsule and a longitudinal capsulotomy is made to expose the scapholunate and lunotriquetral ligaments. A separate 8 cm palmar approach using an extended carpal tunnel incision that crosses the wrist crease is then made. The transverse carpal ligament is released, and the carpus is internally stabilized with an intraosseous wire technique that Almquist et al2 initially used for chronic complete scapholunate separation. We now use a similar technique for acute injuries.61 Small bone anchors are placed for later scapholunate interosseous ligament (SLIL) repair. The suture anchors are routinely placed in the scaphoid, as this is where the scapholunate ligament usually avulses. Occasionally, the scapholunate ligament avulses from the lunate and the suture anchors are then placed in the lunate. The hollow metal cannula of an 18-gauge intravenous catheter is then placed on a power wire driver. The trick is to remove the plastic hub without crushing the hollow metal cannula. This is best accomplished using a needle driver and gently twisting off the plastic hub. The hollow needle is then drilled from dorsal to volar through the proximal pole of the scaphoid as if the scaphoid was reduced (Fig 3A). A 20-gauge wire is then passed through the needle from dorsal to volar (Fig 3B). The cannula is then removed and drilled through the lunate from dorsal to volar as if the lunate were reduced. To avoid retracting the flexor tendons it is easier to pass the scaphoid wire first. The wire is then passed from volar to dorsal through the hollow cannula to complete the circle. The bone anchor sutures are then passed through the torn SLIL. Dorsal Kirschner wires (K-wires) are then placed in the scaphoid and lunate as joysticks. The cerclage wire is tightened with the scaphoid reduced to the lunate, as confirmed by posteroanterior and lateral fluoroscopy. The bone anchor sutures are then tied to repair the ligament without tension (Fig 3C). Bone anchors are inserted to repair the lunate triquetral interosseous ligament (LTIL) if there is sufficient ligament dorsally for repair. Using fluoroscopy, two 0.045 in K-wires are then passed across the triquetrum and into the lunate with the bones reduced. The LTIL bone anchor sutures are then tied to complete the repair (Fig 3D). Tears in the volar capsular ligaments at the space of Poirier are repaired with interrupted sutures. The K-wires are then cut to retract under skin. At the completion of surgery, patients are placed in a sugar tong splint.61

Fig 3A

Fig 3A

Patients return for suture removal and splint change 10-14 days postoperatively, and a short arm cast is applied. Range of motion (ROM) exercises are started at 6-8 weeks postoperatively. Patients also wear a removable wrist splint. The K-wires used for the LTIL repair are removed 8 weeks postoperatively under local anesthesia. As wrist motion is regained the cerclage wire often breaks.3

From July 1990 to July 2000, 22 patients with isolated perilunate dislocations were treated at the University of Washington and previously reported on.61 At the final followup, patient satisfaction was high for 15 of 22 patients. Only 10 patients returned to the same job they had before their injury.20 However, all 22 patients were able to return to some type of work.20 Sixteen of the patients stated they were able to return to their previous level of activity.20 Total ROM of the injured extremity was 87% of the contralateral wrist.20 Grip strength averaged 35 kg in the injured hand compared with 45 kg for the contralateral wrist (77% of contralateral wrist).20 Final follow-up radiographs showed no significant change in scapho-lunate angle or gap with time.20 The cerclage wire often broke with return of ROM.20 The cerclage wire broke in 16 patients and was removed under regional anesthesia.20 This study showed that a combined dorsal and volar approach with an intraosseous wiring technique can restore effectively normal intercarpal relationships, provide acceptable pain relief, functional range of motion and grip strength.61 There have been proponents of either isolated dorsal1,15,32,41 or volar approaches,57 and combined dorsal and volar approaches have been reported with increasing frequency to allow good visualization and facilitate repair of these complex injuries.4,30,35,43,54

We believe that the key to a successful long-term result is a strong repair of the SLIL. We have found that internal fixation with K-wires does not help to compress the scaphoid and lunate together to protect the SLIL repair during the critical period of ligamentous healing. We believe that the intraosseous cerclage wire, however, effectively and reliably reduces and restores normal scapholunate alignment and decreases tension on the SLIL repair during the critical period of ligamentous healing.

A combined dorsal and volar approach was used to provide good visualization, facilitating anatomic reduction of the carpus and passage of the intraosseous cerclage wire. The volar limb of the incision allows for release of the transverse carpal ligament and decompression of the median nerve. Seven of twenty-two patients (32%) had evidence of acute carpal tunnel syndrome. This is an important adjunctive treatment as the incidence of acute carpal tunnel syndrome in these injuries ranges from 16% to 46%.1,4,30,43,54 Further, the volar approach allows for a repair of a tear in the volar capsular ligaments, if present, and facilitates passage of the intraosseous cerclage wire.

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Lunate Dislocations

Our treatment of lunate dislocations is similar to the perilunate dislocations, except that a separate palmar approach may be needed to reduce the lunate. Occasionally, the lunate can be successfully reduced by: (1) flexing the wrist to take the tension off of the palmar ligaments, (2) applying palmar pressure over the hamate followed by wrist extension to reduce the lunate into its fossa on the radius, and (3) by wrist flexion to reduce the capitate into the lunate.49 If the lunate can be reduced by manipulation a dorsal approach is necessary as described for perilunate dislocations. If the lunate cannot be reduced closed, an extended carpal tunnel approach will expose the dislocated lunate and facilitate reduction of the lunate and repair of the volar ligaments.

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Transcaphoid Perilunate Dislocations

Transcaphoid perilunate fracture dislocations account for more than ½ of all perilunate dislocations, with the dorsal type being the most common.26 Closed reduction should be attempted urgently to optimize carpal alignment and help minimize swelling which can increase pressure on the median nerve.

We use a dorsal approach with screw fixation of the scaphoid in all patients. A volar incision is made only in patients that require a simultaneous carpal tunnel release. On rare occasions a volar approach may be necessary for the patients with a transcaphoid perilunate dislocation when the proximal pole of the scaphoid and lunate become buttonholed through the volar capsule.

A longitudinal incision is made over the dorsum of the wrist just ulnar to Lister's tubercle. The extensor pollicis longus is released and retracted radially with the extensor carpi radialis longus. A longitudinal incision is then made in the capsule to expose the scaphoid. The scaphoid is reduced and held with a 0.045 K-wires parallel to the path of the screw (Fig 4). Kirschner wires are needed occasionally to use as joysticks for assisting in fracture reduction. The scaphoid is fixed using a cannulated screw system such as the Accutrak screw (Accumed, Hillsboro, OR). Scaphoids that are comminuted and require bone grafting are grafted using autograft bone obtained from the distal radius thorough the same dorsal incision.

Fig 4

Fig 4

Once the scaphoid is stabilized, the scapholunate and lunotriquetral ligaments are inspected. The scapholunate ligament is usually not disrupted in a transscaphoid perilunate injury.59 However, the lunotriquetral ligament is usually disrupted which requires repair.59 The lunotriquetral joint can be exposed by elevating the fourth extensor compartment. Repair of the ligament is performed using a 1.8 mm bone anchor. The anchor is inserted into the lunate, and the sutures are used to grasp the ligament attached to the triquetrum. The lunotriquetral joint is then reduced and stabilized with K-wires inserted percutaneously from the ulnar side of the wrist prior to tying the sutures (Fig 5). The K-wires are buried beneath the skin for 6-8 weeks and then surgically removed.

Fig 5A

Fig 5A

A long arm splint is applied for 2 weeks postoperatively. When the patient returns for a wound check and suture removal at 2 weeks, they are transitioned into a short arm cast for 4 weeks. Gentle ROM begins 6 weeks postoperatively with strengthening exercises.

We retrospectively reviewed 25 patients treated for a dorsal transcaphoid perilunate fracture dislocation from January 1990 to January 2001. Objective assessment included ROM, grip strength, and radiographs evaluated at the last followup (mean followup 44.3 months, range 25-79 months). Subjective assessment was further evaluated by using a VAS from 1 to 5, with 5 indicating the most satisfaction. Radiographs were taken to assess post reduction scapholunate gap and compared with radiographs taken at the last followup.

The average time to scaphoid union was 16 weeks (10-26 weeks). Among the five scaphoids that underwent primary bone grafting, the average time to union was 18.4 weeks (range, 14-22 weeks). At the last followup examination, 22 of the 25 patients were able to return to their preinjury occupation. Three patients reported problems with activities of daily living. Of these three patients, one patient returned to his preinjury occupation. Two patients did not return to their preinjury occupation, but were able to return to some type of work. The average satisfaction score was 4.32 (range, 3-5).

The combined wrist dorsiflexion and palmarflexion averaged 113° (range, 9°-140°) for the injured wrist. This was an average of 83% of the contralateral wrist with an average range of 133° (range, 120°-145°). Combined radial and ulnar deviation averaged 40° (range, 30°-55°) which was 89% of the contralateral side. The contralateral combined radial and ulnar deviation averaged 45° (range, 35°-60°). Combined supination and pronation was 98% of the uninjured wrist. Combined supination and pronation averaged 152° (range, 120°-185°), while the contralateral wrist averaged 154° (range, 120°-185°). The total ROM of the injured wrist was 91% of the uninjured wrist. Average grip was 38 kg (range, 20-80 kg) for the injured wrist, and 49 kg (rage, 30-75 kg) for the contralateral wrist. Patients achieved 80% grip strength of the uninjured side at last followup.

The average post reduction scapholunate gap was 2.28 mm (range, 2-3 mm). The average final scapholunate gap was 2.56 mm (range, 2-4 mm). Nineteen patients who had post reduction scapholunate gaps of 2 mm or 3 mm had no change in the scapholunate gap. Four patients had a change from 2 mm to 3 mm in the scapholunate gap. One of these four patients required bone grafting. The average followup was 50 months (range, 27-79 months). The average delay to surgery was 4 days (range, 1-9 days). One patient had a change in the scapholunate gap from 3 mm to 4 mm. This patient was followed for 33 months and had an 11-day delay in surgery. One patient had a change in the scapholunate gap from 2 mm to 4 mm. The patient was followup for 66 months and had a 9-day delay in surgery.

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Percutaneous and Arthroscopic Assisted Techniques

Percutaneous and arthroscopic assisted techniques can also be useful in the treatment of perilunate soft tissue injuries and fracture dislocations including transcaphoid perilunate dislocations and transcaphoid transcapitate dislocations.52 The key steps include the percutaneous reduction of carpal fractures, provisional fixation with a K-wire, and placement of a 0.045-inch double-cut Kirschner guide wire along the central axis of the scaphoid and capitate (Fig 6). This permits the later implantation of a cannulated headless compression screws for rigid fixation. Fluoroscopy and traction are used to achieve fracture reduction and guide wire placement. Fluoroscopy and traction are also used to identify gross ligamentous injuries. Arthroscopy is used to confirm fracture reduction, grade ligamentous injury, and identify occult injuries.

Fig 6A

Fig 6A

Fractures are treated first. Opposing fracture surfaces are aligned and firmly opposed with joysticks while headless cannulated compression screws are used to achieve rigid fixation of carpal fractures. Incomplete ligament injuries are debrided and carpal bones are stabilized as needed. Complete carpal disruptions require reduction, provisional wire stabilization, and direct repair with mini bone anchors. These ligamentous repairs are protected with K-wires or cannulated screws until healed. The fluoroscopy unit is used to visualize the carpal bones under static and dynamic conditions. The characteristics of the fracture are compared with preoperative injury films. While complete carpal disruptions will be identified by gapping on static posteroanterior radiographs, malalignment of the lunate in a flexed or extended position on a lateral radiographic view suggests a complete ligament disruption. Traction radiographs are performed with a fluoroscopy unit and may reveal a more significant injury. This is accomplished by applying 5 kg of longitudinal traction to fingers traps attached to the thumb and three fingers. This can be accomplished with arthroscopic traction tower or conventional finger traps with a counter-weight traction on the arm. Traction films may review large carpal gaps where none were seen on a standard radiographs. These studies are used to confirm carpal fractures, identify ligament injuries and occult fractures. Partial injuries may be identified with traction by articular disruptions between the carpal rows and carpal bones.

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Technique

The first priority is the reduction of any remaining carpal dislocation. This is accomplished with longitudinal traction. If carpal alignment cannot be reestablished in a closed manner, open reduction is required either through a dorsal and/or volar approach. The fracture alignment is assessed using a minifluoroscopy unit. If fracture reduction is not satisfactory through a closed manipulation, then 0.062-inch K-wires may be inserted percutaneously into the carpal fracture fragments to serve as joysticks to manipulate the fracture fragments into correct alignment. A small hemostat can be introduced percutaneously into the fracture site to effect a direct fracture reduction (Fig 7). This can be particular useful in the reduction of the rotated proximal pole capitate fracture. With transcaphoid perilunate dislocations, a hemostat can be introduced into the midcarpal portals and with fluoroscopic imaging a carpal reduction can be accomplished. After reduction is accomplished a 0.045 in guide wire is placed down central axis of the carpal bone and is driven across the fracture site to capture and retain reduction. These wires are introduced into the distal fragment prior to final reduction. Once reduction is accomplished, the guide wire is driven proximally to capture the proximal fragment and retain reduction. With grossly unstable fractures a second parallel antirotation guide wire is introduced maintain fracture alignment. The scaphoid wire is introduced dorsal at the proximal scaphoid pole while the capitate wire is introduced between either the II and/or III web space. It is important that these wires be placed down the central carpal bone axis to decrease healing time reduced the risk of thread penetration.51,63

Fig 7

Fig 7

To place the 0.045-inch guide wire along the central scaphoid axis, the wrist is flexed and the forearm pronated in order to view the scaphoid along its long axis. With this view, the scaphoid silhouette appears as a dense circle, which corresponds to the cortex around the long axis. A 0.045-inch K-wire is then inserted in a dorsal to volar direction down the central axis of the circle. Central placement of the wire is then confirmed by fluoroscopy in the coronal and sagittal planes. The K-wire is driven through the trapezium until it penetrates the skin at the radial base of the thumb. A second 0.045-inch K-wire may be needed parallel to the first in order to prevent rotation about the long axis. Take care to keep the wrist flexed until the wire clears to radiocarpal joint so as to not bend the K-wire. This will impair reaming with a cannulated reamer and screw implantation.

To place the 0.045-inch guide wire along the central capitate axis the wire must be introduced between the II and III web space through the base of the long finger CMC joint (Fig 8). This keystone joint is rigid and violation of this joint with a drill leaves only a level joint surface that heals with fibrocartilage. The guide wire passes through the CMC joint into the capitate to secure fracture reduction and provide a path for hand drilling and screw implantation. The introduction of the screw through the web space is critical for proper placement of a screw along the central axis.

Fig 8A

Fig 8A

After fracture reduction and guide wire placement the tourniquet is inflated for an arthroscopic survey. The hand is placed in 5 kg of linear traction utilizing finger traps and a traction tower. The minifluoroscopy unit is used to identify the radiocarpal and midcarpal portal sites and 19-gauge needles are inserted to mark the location. Small, longitudinal skin incisions are made at the needle entry points. A small, curved hemostat is used to spread the subcutaneous tissue away from the capsule and enter the joint. A blunt trochar is then placed into the 3 or 4 portal and a 19-gauge needle remains as outflow for the 6R. A small joint angled arthroscope is inserted and a shaver is placed in the 4, 5, or 6R portal to clear blood clot and hyperplasic synovial tissue. The volar radiocarpal ligaments, interosseous ligaments, and the triangular fibrocartilage complex (TFCC) are stressed with a 2-mm probe.

Next, the midcarpal row is entered in a similar manner at the radial and ulna midcarpal portals. The radial midcarpal portal is the best portal for viewing scaphoid and capitate fracture alignment. The capitate is split at the neck (Fig 9A) and the volar lunate is sheared off with the capsule (Fig 9B). Partial ligament tears are graded and debrided.20 Complete tears with carpal instability are identified and prepared for later repair after carpal reduction with joysticks placed percutaneously, provisional K-wire fixation, and bone anchors.

Fig 9

Fig 9

Once the surgeon is satisfied with fracture reduction, the length of the screw to be implanted must be selected. Having established the appropriate screw length, advance the central axis guide wire well past the far cortex. This will permit carpal reaming without loss of guide wire position. Proximal pole fractures of the scaphoid require dorsal implantation of a headless compression screw for the best fixation.18 Scaphoid waist fractures may be fixed from a dorsal or volar position as long as the screw is along the central axis. Dorsal implantation of the scaphoid screw requires that the wrist be maintained in a flexed position during driving and screw placement to avoid bending the wire. The capitate guide wire located between the II and/or III web space passes through the CMC joint of the long finger. This is the keystone joint is rigid and penetration with the drill is easily tolerated. Finally, insert the properly measured screw. Confirm the screw placement and compression of the fracture site by orthogonal views on the mini-fluoroscopy unit and then remove any remaining K-wires. Wounds including the portal sites are closed with interrupted 4-0 nylon sutures.

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Arthroscopic Evaluation

Carpal ligaments may be evaluated with standard and traction radiographs, fluoroscopy, and arthroscopy. While standard and traction radiographs will identify gross disruptions, fluoroscopy permits a dynamic exam of the carpus for more subtle injuries. Arthroscopy permits a direct inspection and manual testing with an arthroscopic probe of the volar and intracarpal ligaments.

Arthroscopy permits the grading and treatment of partial ligament injuries.20 Most of these injuries are raised flaps and future painful carpal irregularities. These may be satisfactory treated with debridement alone. Significant carpal ligament tears (Geissler II or III) may require debridement and temporary carpal immobilization with K- wires.20 Carpal instability may result from partial or complete ligament disruptions and carpal fracture. Percutaneous carpal reduction with c-linear alignment of the capitate, lunate, and radius and fracture repair may be sufficient to reestablish carpal stability without open ligament repair.

These injuries must be reexamined after carpal fracture fixation with fluoroscopy. Radial styloid avulsion with its volar attachments of the radial scaphocapitate ligament (RSL) and long radial lunate ligament (LRL) can be provisionally stabilized with 0.045 in guide wire and rigidly fixed percutaneously with a cannulated screw. Rigid fixation of the scaphoid fracture with its proximal and distal ligament attachment may be enough to reestablish wrist stability.

If fluoroscopy and arthroscopy confirm persistent carpal instability after fracture fixation, then complete disruptions of the carpal interosseous and volar capsular ligaments require direct repair. Using radiographic imaging, stout K-wires (0.062 in) are placed percutaneously as joysticks and the disrupted carpal bones are realigned and provisionally secured with additional K-wires. If persistent carpal gapping is viewed on imaging after attempting carpal reduction, then soft tissue interposition is suggested. This obstruction can be removed with an arthroscopic instruments and an aggressive shaver. Additional provisional K-wires may be placed from the radius into a reduced and correctly aligned lunate to assist in carpal alignment. Extending the 3, 4 arthroscopic portal incision exposes the third dorsal compartment. This is opened, and the extensor pollicis longus is retracted radially. The dorsal capsule is incised and retracted exposing the disrupted dorsal SLIL. This is usually avulsed off the proximal pole of the scaphoid. Mini bone anchors are placed in the proximal scaphoid pole and the SLIL ligament is reattached. This repair is protected by securing the scaphoid to both the lunate and capitate with 0.062 in K-wires or cannulated screws. Similarly, disruption of the LTIL is addressed by extending the 4,5 arthroscopic portal incision distally exposing the fourth dorsal compartment. Tendons are retracted and the dorsal capsule incised exposing the disrupted lunotriquetral ligament. The lunate and triquetrum are reduced using joysticks. 0.062 in K-wires direct from the radius into lunate lock it position. An ulna to radial directed K-wire secures the reduced lunate to the triquetrum. Mini bone anchors or direct repair are used to reestablish ligament continuity. The lunate triquetral wire can be replaced with a cannulated screw protecting the lunotriquetral interosseous ligament repair. If this repair needs supplemental ligament tissue for support, a dorsal capsulodesis can be applied by extending the dorsal longitudinal incision radially into a proximal based rectangular flap.

The dressings and sutures are removed at 7-10 days postoperatively, a short arm cast is applied, and supervised hand therapy program is initiated to restore hand function. Complete ligament injuries will require 6 weeks of immobilization in a short arm cast, followed by 6 weeks of a protected motion program with a thumb spica splint. Kirschner wires are removed at 2-3 months. Fractures of the waist without complete ligament injuries are started on an immediate ROM protocol. All fractures are started on a strengthening program. The purpose being to axially load the fracture site now secured with an intramedullary screw to stimulate healing. Heavy lifting and contact sports are restricted until computed tomography (CT) confirms healing of fractures by bridging callous, and clinically the patients are nontender. Ligament injuries require 3 months to heal followed by an intensive therapy program to recover wrist functions.

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Delayed Treatment

Delayed presentation or diagnosis of these injuries is not uncommon. While some patients are minimally symptomatic, long-term followup of untreated injuries suggests the outcome is typically poor. Pain, weakness, and loss of motion are common with posttraumatic arthrosis, carpal tunnel syndrome, and attritional flexor tendon ruptures.27,29 In the largest series of perilunate injuries reported, 15 patients were identified who were untreated for an average of 22 years.26 These patients had worse clinical scores than those treated by any method at any time after injury.8 Because of the relatively dismal natural history, surgery should be considered regardless of the time since injury.

Late treatment options include ORIF, lunate excision, proximal row carpectomy, and wrist fusion. Few series are available to compare these options. Seigert et al17 reviewed a series of 15 patients with perilunate injuries treated at an average of 17 weeks after injury (minimum, 6 weeks) with mean 6-year followup. Open reduction and internal fixation was performed in six patients, carpal bone excision in four patients, proximal row carpectomy in two patients, wrist arthrodesis in two patients, and carpal tunnel release in one patient.50 Although the numbers are small, ORIF provided the most reliable improvement.17 Proximal row carpectomy and wrist fusion produced significant improvement, but the level of improvement did not exceed open reduction.17 In the patient troubled only by symptoms of carpal tunnel syndrome, simple release provided expected relief.17 Patients treated with carpal bone excision alone did uniformly poorly.17

Inoue and Shionoya reported on 28 patients with perilunate injuries treated at least 6 weeks after injury with a mean 6-year followup.33 Proximal row carpectomy was performed in 16 patients, ORIF in six patients, lunate excision in four patients, and carpal tunnel release with partial lunate excision in two patients.9 The best clinical results were achieved in patients treated with ORIF.9 Proximal row carpectomy was reported as a reasonable option for patients without damage to the articular surface of the capitate.9 Lunate excision alone was a poor treatment option.9

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DISCUSSION

Perilunate injuries severely disrupt normal wrist function and are prone to poor clinical outcomes if untreated. Outcomes are improved by early diagnosis, accurate reduction, and stable internal fixation. Even when presentation is delayed, surgery should be considered to maximize recovery of function. Closed reduction often achieves gross realignment of the wrist, but accurate reduction of the small irregular carpal articulations generally requires open reduction. A dorsal approach provides the best view of these small joints, but a volar approach may be necessary as well. Kirschner wires inserted into the carpal bones allow direct manipulation and facilitate accurate reduction. These injuries are highly unstable and always require temporary pin fixation to reliably maintain reduction. Open reduction should be considered even after long delays since injury.3,21,33,44,50,56 Although it becomes progressively more difficult, there is no absolute time after which open reduction cannot be performed. Reduction offers the greatest potential of recovering more normal wrist biomechanics and preserves proximal row carpectomy and wrist fusion as treatment options.58 Proximal row carpectomy is a reasonable option if reduction cannot be achieved, and if the head of the capitate has not been significantly injured. Fusion is also effective in relieving pain and improving strength.24,33,34,46,50

Carpal fracture dislocations are often difficult injuries to treat. They are often subtle to diagnose and require prompt treatment. The resultant deformities are often predictable due to the normal anatomic relationships. Treatment of these injuries is aimed at restoring these complex anatomical relationships and follows a stepwise algorithm that first restores bony anatomy and then intercarpal relationships. We recommend ligament repair at the time of open reduction and recreation of the normal carpal anatomy.3,44,56,61 If the interosseous ligaments are not repaired predictable deformities develop. In transcaphoid perilunate injuries when the scaphoid fracture heals and the LTIL is not repaired a volar intercalated segment instability (VISI) pattern results.6,8,39-41 The same holds true for perilunate dislocations when the SLIL is repaired but the LTIL is not repaired.6,8,39-41 Palmer et al reviewed results in four patients treated with open reduction, pin fixation, and ligament repair compared with six patients treated with reduction, pin fixation, and ligament repair.16 Patients without ligamentous repair did well, although intercarpal relations were maintained more consistently in the repaired group.47 Minami and Kaneda15 reviewed results in 12 patients treated with open reduction and interosseous ligament repair compared with 20 patients treated with open reduction and pin fixation without ligament repair. Repair or reconstruction of the dorsal scapholunate interosseous ligament improved clinical results and reduced the incidence of carpal instability at an average of 5 years of followup.44

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