Perilunate Fracture Dislocations

Updated: Sep 21, 2022
Author: Peter M Murray, MD; Chief Editor: Harris Gellman, MD 


Practice Essentials

Perilunate dislocation and perilunate fracture dislocation are injuries that involve traumatic rupture of the radioscaphocapitate (RSC) ligament, the scapholunate interosseous (SLI) ligament, and the lunotriquetral interosseous (LTI) ligament.[1, 2, 3, 4]  In some instances, these injuries may be associated with disruption of the short radiolunate ligament.[5] Fractures of the radial styloid, the scaphoid, the trapezium, the capitate, and the triquetrum also may be associated with the dorsal or the volar perilunate dislocation. The result of perilunate dislocation and of perilunate fracture dislocation is an extremely unstable wrist, potentially producing devastating complications.[6]

Perilunate dislocations and perilunate fracture dislocations are the most devastating closed injuries of the wrist.[7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]  They often are missed on initial evaluation, leading to devastating complications. These injuries occur as the final stage of a spectrum of injuries progressing around the wrist in a radial-to-ulnar direction.

Before the advent of radiography, fractures of the distal radius, carpal instability, and carpal dislocations were at best difficult to distinguish. In 1855, Malgaine was the first to publish a description of perilunate fracture dislocations. Later, Cousins, Destot, and de Quervain reported on this injury. Tavernier reported the first true series in 1906. Destot contributed greatly to the general understanding of wrist instability in the work Injuries of the Wrist: A Radiographic Study (1918).[18]

Subsequently, enthusiasm for the study of wrist instability was lost until 1968, when Fisk presented the Royal College of Surgeons Hunterian Lecture on the concept of the intercalated segment, referring to the kinematics of the proximal carpal row. In 1972, Linscheid et al further modified this concept by introducing the terms volar intercalated segment instability (VISI) and dorsal intercalated segment instability (DISI).[19]  In 1980, Mayfield et al illustrated the mechanism of perilunar wrist instability as a series of four stages resulting in perilunate dislocations or lunate dislocations.[20]

In the setting of a high-energy wrist injury, radiographs must be scrutinized carefully for perilunate dislocation or one of its variants. Prompt open reduction with ligamentous repair or reconstruction is necessary to achieve favorable results.[21] Posttraumatic arthrosis may result after these injuries irrespective of treatment, requiring a late salvage operation.

For patient education resources, see Wrist Injury.


The carpus is composed of two rows of bones, as follows[22] :

  • Proximal carpal row (scaphoid, lunate, and triquetrum)
  • Distal carpal row (trapezium, trapezoid, capitate, and hamate)

The wrist joint is composed of the following two types of ligaments:

  • Intrinsic - These ligaments are short, stout ligaments that stabilize adjacent carpal bones
  • Extrinsic - These ligaments span the proximal carpal row and the distal carpal row

Within the proximal carpal row, the SLI ligament binds the scaphoid to the lunate.[23] This ligament has the following three portions:

  • Proximal
  • Distal
  • Volar

The dorsal portion of the ligament supplies the majority of stabilizing strength to the scapholunate articulation. The LTI ligament secures the articulation of the lunate and the triquetrum. Although stout, the interosseous ligaments of the proximal carpal row allow relative motion between the scaphoid and lunate and between the lunate and the triquetrum.

The distal carpal row is also stabilized by intrinsic ligaments, such as the capitohamate ligament, which is composed of dorsal, deep, palmar, and longitudinal components.

The scaphotrapeziotrapezoidal (STT) joints are stabilized by a ligamentous complex that is intrinsic and extrinsic in nature and includes the following:

  • Scaphotrapezial ligament
  • Scaphocapitate capsular ligament
  • Dorsal and palmar STT capsular ligaments

The extrinsic carpal ligaments provide the structural integrity for the articulations of the proximal and distal carpal rows. The RSC ligament originates from the radial styloid, crosses the waist of the scaphoid, and inserts on the volar waist region of the capitate.

Immediately ulnar to the RSC ligament is the radiolunotriquetral (RLT) ligament, which originates from the radial styloid, sends an attachment to the volar aspect of the lunate, and then terminates on the triquetrum. The short radiolunate ligament originates from the most ulnar aspect of the distal radial articular surface and inserts on the proximal volar aspect of the lunate.

From the base of the ulnar styloid, two ligaments—the ulnocapitate and the ulnotriquetral—originate. A portion of the ulnotriquetral ligament continues across the midcarpal joint to insert on the waist of the capitate and join the RSC ligament, forming an inverted V. This ligament is known as the ulnocapitate ligament, and the inverted-V confluence is known as the arcuate ligament. Just proximal to the base of the V is a soft spot, the space of Poirier.

Found between the short radiolunate ligament and the RLT ligament is the radioscapholunate (RSL) ligament, which is also known as the ligament of Testut. The designation of this structure as a ligament is actually a misnomer: Histologic studies have shown that it is a vascular structure devoid of any true collagen fibers and that it lacks structural integrity.

Within the dorsal capsule of the wrist are two ligaments of particular importance:

  • Dorsal intercarpal ligament
  • Dorsal radiocarpal ligament

The former courses transversely from the waist of the scaphoid across the carpus, inserting onto the dorsal aspect of the triquetrum; the latter spans a distance from its origin on the radial styloid to its place of insertion on the dorsal aspect of the triquetrum. Together, these two ligaments form a V, with the base of the V on the triquetrum. Between the limbs of the V is the less substantial dorsal wrist capsule.


Pure ligamentous perilunar injuries of the wrist are classified as lesser-arc injuries, whereas the transosseous variants are regarded as greater-arc[24] injuries. The mechanism of perilunate dislocations has been described as a four-stage process, as follows:

  • First stage - The RSC ligament and the SLI rupture
  • Second stage - Dislocation of the capitolunate joint occurs as the injury progresses through the space of Poirier
  • Third stage - The LTI ligament ruptures
  • Fourth stage - The lunate becomes dislocated

This mechanism has been reproduced in a cadaver model by applying pronation and ulnar deviation on a hyperextended cadaver wrist.


Perilunate dislocations and perilunate fracture dislocations typically occur in young adults who are exposed to high-energy trauma, such as a fall from a height. In these injuries, the fall generally results in the wrist being axially loaded by the body, trapping the hand in the hyperextended and ulnarly deviated position. The angle of hyperextension determines the extent of injury. If sufficient loads are applied, the ulnarly deviated wrist, hyperextended beyond 100º, produces a perilunate dislocation or one of the fracture dislocation variants.


Little is known about the true incidence of perilunate dislocations and perilunate fracture dislocations. Because the subtlety of wrist injuries often is not fully appreciated, many believe that perilunate injuries in general are underdiagnosed. Perilunate dislocation, lunate dislocation, and perilunate fracture dislocation variants have been estimated to account for fewer than 10% of all wrist injuries. In a study reviewing perilunate dislocations, 61% were of the transscaphoid perilunate type.


The outcomes of perilunate dislocations and perilunate fracture dislocations are best when emergency reduction of the carpus is performed, followed by accurate open reduction and internal fixation (ORIF). The incidence of carpal instability and subsequent posttraumatic arthritis is believed to be reduced with ORIF, including accurate repair or reconstruction of the SLI ligament.

The combination of dorsal and volar approaches to the wrist in the treatment of perilunate dislocations has been studied; however, the prognosis of these injuries remains guarded because of the significant incidence of posttraumatic arthritis, which can occur irrespective of treatment.[10] Capo et al reported reasonable and functional clinical results after treatment of perilunate fracture dislocations with a combined volar-dorsal approach.[25]

Krief et al retrospectively studied 30 patients with perilunate dislocation (n = 14) and perilunate fracture dislocation (n = 16) to evaluate clinical, functional, and radiologic outcomes at a mean follow-up of 18 years (range, 15-24 y).[26] Relative to the contralateral side, the mean flexion-extension arc was 68%, the radial-ulnar abduction arc 67%, the pronation-supination arc 80%, and the mean grip strength 70%. The mean Mayo wrist score (MWS) was 70, the mean Quick Disabilities of the Arm Shoulder and Hand (QuickDASH) score 20, and the Patient-Rated Wrist Evaluation (PRWE) score 21. Five patients underwent a secondary procedure, and six had a complex regional pain syndrome type 1.

Garçon et al retrospectively studied 32 patients who had either an isolated perilunate dislocation (n = 7) or a fracture-dislocation (n = 25) in their wrist, evaluating oain, range of motion (ROM), strength and functional scores (MWS, PRWE, QuickDASH).[27]  They found that opening of the carpal tunnel and greater displacement of the lunate were significant predictors of a poor long-term functional outcome and that older age at the time of injury was a predictor for the development of osteoarthritis.



History and Physical Examination

Most patients present acutely after a fall from a height onto a dorsiflexed wrist. Patients with perilunate dislocations and perilunate fracture dislocations may demonstrate obvious clinical deformities, such as marked swelling, or they can present rather innocuously, complaining of a sprained wrist. In the dorsal perilunate dislocation or one of its transosseous variants, the carpus is dislocated dorsally, and the radius is prominent volarly; in the pure lunate dislocation, the lunate alone is prominent volarly. These injuries are diagnosed late in as many as 25% of cases.

Because of the high-energy nature of perilunate fracture dislocations, a careful, thorough trauma survey with assessment for associated injuries of the head, thorax, and extremities is imperative. Damage to the median nerve is the most common associated injury in lunate and perilunate dislocations of the wrist. In certain situations, volar skin lacerations could represent an open dislocation or fracture dislocation.

Additionally, the volar skin can become ischemic because of pressure from the volar radius (resulting from dorsal dislocation of the hand). With long-standing perilunate dislocations, patients may present with arterial compromise or established compartment syndromes.




Although perilunate dislocations are frequently missed, the diagnosis should be made on the initial injury plain films.[28, 29]  One cause of a missed diagnosis is inadequate posteroanterior (PA) and lateral radiographs. Other causes include radiographs obscured by splints and unfamiliarity with the anatomy of the carpus. When trauma to the carpus is suspected, it is incumbent upon the examining physician to obtain acute plain radiographs that are devoid of splint materials and dressings.

Standard PA, lateral, and oblique radiographs centered over the carpus should be obtained in all patients with significant wrist injury.

The PA radiograph is obtained with the patient seated, the shoulder abducted 90º, and the hand placed palm-down on the radiographic cassette. This positioning of the shoulder places the forearm in neutral rotation. In the acute setting, a PA distraction view of the carpus can be very helpful for better defining the injury anatomy. For example, small fractures or dislocations of the carpal bones may be better depicted by using the distraction PA radiograph. (See the images below.)

Posteroanterior plain radiograph of dorsal perilun Posteroanterior plain radiograph of dorsal perilunate dislocation. Note reduction of radiolunate articulation.
Posteroanterior radiograph demonstrating transradi Posteroanterior radiograph demonstrating transradial styloid dorsal perilunate dislocation.

A series of lines, described by Gilula, can be traced along the proximal edges of the scaphoid, lunate, and triquetrum, as well as along the proximal poles of the capitate and hamate.[30]  The lines should be smooth and uninterrupted. The reference lines can be a quick screen for perilunate dislocation or perilunate fracture dislocation.

The lateral radiograph also is obtained with the patient seated. The shoulder is adducted with the hand and wrist at the side, enabling the ulnar border of the hand to be placed on the cassette. Care should be taken to avoid excessive ulnar deviation of the wrist, because this will give the false impression that the lunate is in the extended position. With the lunate in the extended position, the diagnosis of dorsal intercalated segment instability (DISI) could be made incorrectly.

A correct lateral radiograph of the wrist should have superimposition of the lunate, proximal scaphoid pole, and triquetrum. The radial styloid should appear centered within the metaphysis of the radius, and the metacarpal shafts should all line up. (See the image below.)

Lateral wrist radiograph demonstrating dorsal peri Lateral wrist radiograph demonstrating dorsal perilunate dislocation.

The lateral radiograph should be observed carefully for the wide carpus sign, in which the capitate is overriding the dorsal aspect of the lunate in the dorsal perilunate dislocation. In the volar lunate dislocation, the lunate is clearly volar to the radius. Although much less common, the perilunate dislocation may occur volar and the lunate dislocation dorsal.

In addition, the lateral scapholunate angle and the capitolunate angle on the lateral radiograph should be evaluated. The lateral scapholunate angle is formed by the intersection of the longitudinal axes of the lunate and the scaphoid. Normally, this angle is 30-60º. The capitolunate angle is normally 0-15º. Disruption of these angles may imply scapholunate dissociation.[31, 32, 33]

The oblique radiograph is taken as a 45º off-plane PA radiograph.

CT and Plain Tomography

In most situations, neither computed tomography (CT) nor plain tomography is needed to diagnose perilunate dislocations or perilunate fracture dislocations. However, these studies can be helpful for better defining greater-arc fractures, such as scaphoid fractures, capitate fractures, radial styloid fractures, and triquetral fractures.

In most situations, 1-mm CT scan cuts in the sagittal and coronal plane of the capitate are helpful. If a fracture of the scaphoid is suspected, it is more appropriate to obtain the 1-mm cuts in the plane of the scaphoid.



Approach Considerations

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 Therapy

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.)

Dorsal approach to wrist demonstrating disruption Dorsal approach to wrist demonstrating disruption of scapholunate interosseous ligament.

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.)

Capsulotomy approach to scapholunate interosseous Capsulotomy approach to scapholunate interosseous interval, with preservation of dorsal intercarpal and dorsal radiocarpal ligaments. Image adapted from The Wrist: Diagnosis and Operative Treatment (Mosby, 1998).
Reflected dorsal wrist capsulotomy preserving dors Reflected dorsal wrist capsulotomy preserving dorsal intercarpal and dorsal radiocarpal ligaments. Image adapted from The Wrist: Diagnosis and Operative Treatment (Mosby, 1998).

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).

Drawing showing reduction of scapholunate interval Drawing showing reduction of scapholunate interval with Kirschner wire (K-wire) joysticks. Drill holes are made with straight needles for subsequent passage of suture. This scapholunate repair technique was originally described by Taleisnik.

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.)

Drawing demonstrating suture anchor placement for Drawing demonstrating suture anchor placement for repair of scapholunate interosseous ligament. Image adapted from The Wrist: Diagnosis and Operative Treatment (Mosby, 1998).

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.)

Drawing showing repair of the scapholunate interos Drawing showing repair of the scapholunate interosseous ligament using drill holes and suture passed with straight needles, as described by Taleisnik. Image adapted from The Wrist: Diagnosis and Operative Treatment (Mosby, 1998).
Drawing showing final repair of scapholunate inter Drawing showing final repair of scapholunate interosseous ligament using drill holes, as described by Taleisnik. Image adapted from The Wrist: Diagnosis and Operative Treatment (Mosby, 1998).

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.)

Volar wrist approach for repair of transverse caps Volar wrist approach for repair of transverse capsular rupture (injury typically seen in perilunate dislocations).

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.

Postoperative Care

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.)

Postoperative posteroanterior radiograph after ope Postoperative posteroanterior radiograph after open reduction and percutaneous pinning of dorsal perilunate dislocation. Note that suture anchors have been placed in scaphoid to directly repair scapholunate interosseous ligament. Suture anchors have also been used in distal radius to perform capsulodesis using dorsal intercarpal ligament.


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]

Long-Term Monitoring

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.