Perilunate Fracture Dislocations Treatment & Management

Treatment indications and contraindications

To achieve optimal treatment results, all perilunate dislocations and all perilunate fracture dislocations must undergo accurate open reduction and internal fixation (ORIF) as soon after the injury as possible. ^{[21, 28]}

Like other dislocations, a perilunate dislocation is an emergency and should be reduced as soon as possible. This may be performed in the emergency department (ED), with delay of the definitive procedure. Any fracture associated with perilunate dislocations typically requires stabilization with small compression screws or percutaneous pins. It is sometimes necessary to delay the definitive procedure because of the patient's overall condition, excessive swelling of the wrist and hand, or the need for appropriate surgical assistance.

If, once the perilunate dislocation is reduced, the definitive procedure is delayed, the patient should be observed carefully for skin or neurologic compromise. Once reduced, the extremity is elevated and iced until the definitive procedure is performed. If closed reduction cannot be obtained in the ED, the patient must be taken promptly to the operating room (OR) for open reduction. Median nerve palsy is the most common complication after delayed reduction of perilunate dislocation and perilunate fracture dislocation.

Only a life-threatening condition should delay the prompt reduction of a perilunate dislocation or a perilunate fracture dislocation. Even in this dire circumstance, however, a closed reduction can generally be performed without compromising the treatment of the life-threatening condition that takes priority. Once the fracture is reduced, definitive treatment can be delayed until the patient's condition has been stabilized or optimized.

Developments in treatment

The improvement of treatment for perilunate dislocation and perilunate fracture dislocation requires the development of better alternatives for carpal ligament repair and reconstruction.

Techniques for accurate repair or reconstruction of the scapholunate interosseous (SLI) ligament have not permitted early motion of the wrist. These techniques have employed percutaneous Kirschner wire (K-wire) fixation. Advances in techniques to allow early motion would improve outcome parameters, such as range of motion (ROM) and strength. Further advances in internal fixation of associated carpal fractures could also accelerate the initiation of motion and strengthening.

A remaining issue in the treatment of perilunate dislocation and perilunate fracture dislocations is the need for a single dorsal approach versus the need for a combined dorsal-volar approach to the wrist. ^[34]  The combined dorsal-volar approach affords superior exposure of the wrist joint, enhancing the surgeon's ability to acquire an anatomic reduction of the carpus. Additionally, the volar approach enables repair of the transverse capsular/ligamentous rupture, a uniformly seen result of these injuries.

Perhaps a less contentious topic concerns the actual need for open reduction, given that these injuries have often been treated by closed means with percutaneous pin fixation. Percutaneous pin fixation after closed reduction alone is regarded by most to be insufficient management for the perilunate dislocation and the perilunate fracture dislocation.

Arthroscopic treatment may come to play a more significant role in the treatment of perilunate injuries. ^{[35, 36, 37]}  A retrospective study by Herzberg et al suggested that for selected perilunate injuries, arthroscopy may be a reliable therapeutic approach either alone or in conjunction with a dorsal miniopen approach. ^[38]  

Surgical options include the following:

• Closed reduction and casting ^[39]
• Closed reduction and percutaneous pin fixation ^[40]
• Open reduction and open ligamentous repair with internal fixation ^[41] or with percutaneous pin fixation

The surgical treatment of choice is open reduction and ligamentous repair with percutaneous pin fixation. In most settings, however, if a distal radial styloid fracture or a carpal bone fracture accompanies the perilunate dislocation, internal fixation is preferred.

Some authors have suggested proximal-row carpectomy as initial treatment for perilunate dislocations. A study by Muller et al found this procedure to yield medium-term results at least as good as those of ORIF in this setting, with shorter operating tiems and immobilization periods. ^[42]

Preparation for surgery

A thorough preoperative physical examination is essential because the patient's neurologic and vascular status must be known and documented before surgical treatment is initiated. The examination should include strength assessment of the abductor pollicis brevis of the thumb, as well as two-point discrimination determination over the median nerve distribution of the hand.

Additionally, an Allen test should be performed to assess the integrity of the radial and ulnar arteries at the wrist. The patient may experience difficulty cooperating with the fist pumping needed to perform the Allen test. Therefore, a Doppler Allen test must be performed.

The dorsal and volar skin must be carefully scrutinized before the surgical procedure. As long as the radiocarpal and midcarpal joints have been reduced preoperatively, definitive reconstruction of the wrist can be delayed until the condition of the skin improves. It is essential that adequate preoperative radiographs be obtained and made available before the planned surgical procedure.

If definitive surgical management of the perilunate dislocation or fracture dislocation is delayed, closed management of the radiocarpal and midcarpal joints must proceed on an emergency basis. A well-padded plaster splint is applied once the carpus is reduced so as to maintain the reduction. If the patient is taken to the OR on an emergency basis and a closed reduction has not been attempted in the ED, the wrist should be splinted in a well-padded plaster mold to prevent injury progression and control pain.

Operative details

Once informed consent has been obtained and the surgeon has again identified the affected extremity, the patient is taken to the OR. The patient is positioned supine on the operating table, and the affected extremity is placed on a radiopaque hand table. Because the duration of the procedure may be long, padding should be placed beneath the knees and heels, and the use of a Foley catheter should be considered. An upper-arm tourniquet is applied, being well padded, and the tourniquet is inflated after the arm is prepared and draped.

Attention is turned first to the dorsum of the wrist, where a midline longitudinal incision is made and the extensor retinaculum is exposed. (See the image below.)

The extensor retinaculum is divided between the third and fourth dorsal compartments, and the dorsal wrist capsule is exposed. The dorsal radiotriquetral and dorsal intercarpal ligaments are identified. A radially based dorsal V capsulotomy is performed, with the base of the V at the intersection of the dorsal intercarpal and radiotriquetral ligaments. This capsulotomy preserves these dorsal ligamentous structures, which are known to play a role in the stability of the wrist. (See the images below.)

Through this capsulotomy, accurate reduction of the radiocarpal and midcarpal joints is accomplished. It is imperative that the scaphoid be contained securely in the scaphoid fossa and that the lunocapitate articulation be reduced completely. The lunate is derotated from its dorsal position and stabilized with a 0.062-in. K-wire, which is directed from the radial styloid into the body of the lunate. ^[43]  The lunate reduction is extremely important, because once it is done, the remainder of the carpus can be reconstructed (see the image below).

The scapholunate ligament is identified, and one of two methods is chosen for ligamentous repair. In the first method, two small suture anchors are placed into the defect of the scaphoid proximal pole. This defect typically is created after avulsion of the SLI ligament. The accompanying suture attached to the suture anchors can then be placed through the scapholunate ligament, with the ligament secured once the scapholunate interval is reduced. (See the image below.)

In the second, two small drill holes are created from the defect in the proximal pole, exiting at the waist of the scaphoid along its radial ridge. The holes are created with a 2-mm drill, and a 2-0 nonabsorbable suture is placed through the SLI ligament. Once reduction of the scapholunate interval is ensured, two 0.045-in. K-wires are advanced from the scaphoid into the lunate. A third wire is passed from the midwaist region of the scaphoid into the waist region of the capitate. Once the reduced scapholunate interval is secured, the sutures are tied. (See the images below.)

Similarly, an attempt may be made to repair the lunotriquetral interosseous (LTI) ligament, though this generally proves technically difficult. The surgeon often resorts simply to pinning the lunotriquetral interval percutaneously. The midcarpal articulation is stabilized with the pinning of the scaphoid to the capitate.

In the transosseous variants of perilunate dislocation, internal fixation of the fractures is preferable. Scaphoid fractures, for example, should be reduced and stabilized with a cannulated compression screw, as should capitate fractures.

Radial styloid fractures, triquetral fractures, and smaller varieties of capitate or scaphoid fractures may be better suited for reduction and stabilization with percutaneous K-wire fixation. The placement of percutaneous K-wires, as well as the assessment of the midcarpal joint reduction or of the scapholunate interval reduction, is carried out with intraoperative fluoroscopy.

Once the perilunate dislocation or the perilunate fracture dislocation has been reduced and stabilized successfully, attention is turned to the volar aspect of the wrist. An extensile carpal tunnel approach is used to expose the volar wrist capsule, and the carpal tunnel is released. A transverse rent in the volar wrist capsule is routinely found and should be repaired with 2-0 nonabsorbable suture. (See the image below.)

The tourniquet is released before closure, and the wounds are closed once hemostasis is obtained. A sterile dressing is applied, followed by a well-padded volar plaster splint. External fixation should be considered in the setting of marked swelling or open wounds. It should also be considered when patient compliance is a concern or fixation stability is in question.

Upon completion of the surgical procedure, the hand should be elevated for 48 hours, and the patient's neurologic and vascular status should be monitored. Overnight admission to the hospital is recommended. A small pullout drain generally is recommended for both wounds. Sometime between postoperative days 3 and 5, the dressing and splint should be removed so that the wounds can be examined. At 10-14 days, the sutures are removed, and a short arm cast is applied. (See the image below.)

Complications of perilunate dislocations and perilunate fracture dislocations are devastating, particularly those that occur in patients who have not been treated. If left untreated, these injuries can be expected to cause pain, loss of motion, and median nerve dysfunction. Significant swelling may occur after these injuries, potentially resulting in the development of compartment syndrome of the hand. Unreduced dislocations of the carpus can cause skin ischemic pressure necrosis, again underscoring the need for prompt, accurate reduction of the carpus. ^[28]

Despite early and accurate treatment, stiffness, weakness, and osteoarthritis can be expected to occur in the long term. The development of latent carpal instability is particularly difficult to prevent; this condition may include the development of carpal instability dissociative (CID) in either the volar intercalated segment instability (VISI) form (CID-VISI) or the dorsal intercalated segment instability (DISI) form (CID-DISI). ^{[44, 45]}

Other possible instability patterns include ulnar translocation of the carpus (a form of carpal instability nondissociative [CIND]) and pure midcarpal instability, which can take the form of either the DISI or the VISI pattern (CIND-DISI or CIND-VISI). This form of instability is also known as capitolunate instability. Finally, a combination of dissociative and nondissociative instability patterns may result, creating carpal instability complex (CIC).

In a multicenter study of 166 perilunate dislocations and fracture dislocations, the follow-up incidence of posttraumatic arthritis was 56%. ^[46]

Perilunate fracture dislocations can also be complicated by fracture nonunion. Scaphoid fractures in the setting of a perilunate dislocation can be expected to have a higher incidence of nonunion than do isolated scaphoid fractures. ^[47]

After open reduction and ligamentous repair of the perilunate dislocation, the cast is maintained for 3 months. Radiographs are obtained periodically to ensure maintenance of midcarpal and radiocarpal reduction. Upon cast removal, the patient is placed in a removable splint, and gentle ROM exercises are begun. Splinting is continued until 6 months after surgery. Full activity is not renewed until 8 months after surgery.