Alexander H. Payatakes, Alex M. Meyers, and Dean G. Sotereanos
DEFINITION
Scapholunate and lunotriquetral interosseous ligament tears are common wrist injuries occurring in isolation or as part of the perilunate injury pattern.
Interosseous ligament injuries are being diagnosed with an increased frequency as a result of recent advances in imaging and arthroscopy.
Management of these injuries has proven to be a difficult clinical problem. Surgical management has been more reliable in pain relief than in altering the natural history.
ANATOMY
The scapholunate complex is subject to significant loads, since the scaphoid is the only carpal bone to span from the proximal to the distal carpal row.
The proximal carpal row flexes with radial deviation and extends with ulnar deviation.
The scaphoid “wants” to flex and the triquetrum “wants” to extend.
The lunate (the intercalated segment) is tethered between the scaphoid and triquetrum. A large amount of potential energy exists in the proximal carpal row.
Stability is provided to the scapholunate complex by the intrinsic scapholunate interosseous ligament (SLIL) as well as extrinsic capsular ligaments, especially the dorsal radiocarpal (DRC), dorsal intercarpal (DIC) ligament, and volar radioscaphocapitate (RSC) and scaphotrapezium-trapezoid (STT) ligaments.
The SLIL is a C-shaped structure consisting of a stronger dorsal ligamentous portion (2 to 3 mm thick), a volar ligamentous portion (1 mm thick), and a proximal fibrocartilaginous (membranous) portion.2
Isolated injuries to the SLIL appear to be associated with dynamic instability, whereas static instability usually indicates additional injury to the secondary ligamentous stabilizers, including the DIC ligament.16
The lunotriquetral complex is also stabilized by an intrinsic lunotriquetral ligament (LTIL) and extrinsic (volar and dorsal) capsular ligaments.
The LTIL is C-shaped, analogous to the SLIL, consisting of dorsal and volar ligamentous portions and a membranous proximal portion. In contrast to the SLIL, the volar ligamentous portion of the LTIL is stronger and more significant functionally.12
As with the scapholunate complex, isolated injuries to the LTIL are usually insufficient for the development of static instability. Presence of a static deformity indicates additional injury to extrinsic ligamentous structures (volar ulnotriquetral, ulnolunate, and ulnocapitate ligaments or the dorsal radiocarpal and intercarpal ligaments).7,20
PATHOGENESIS
Mayfield et al9 postulated that scapholunate disruption is the initial component of the lesser arc perilunate injury pattern, which occurs when force is applied to the thenar area with the wrist in extension, supination, and ulnar deviation.
Depending on the amount of kinetic energy involved, the injury may or may not extend to the ulnar side of the wrist.
SLIL injuries can be sprains, partial tears, or complete tears (with or without injury to the extrinsic ligament stabilizers).
With complete SLIL tears the scaphoid flexes and the lunate is pulled by the triquetrum into extension (dorsal intercalated segment instability [DISI] pattern).
With complete SLIL tears the ligament usually fails at the bone–ligament interface off the scaphoid.
Arthroscopic evaluation has revealed associated SLIL injuries in up to 30% of intra-articular distal radius fractures.5
LTIL disruption may be traumatic or atraumatic in origin.
Traumatic LTIL rupture may occur as the final component of a greater or lesser arc perilunate injury pattern.9
Isolated LTIL tears may result from a fall on an outstretched hand in extension, pronation, and radial deviation (reverse perilunate injury)11 or from a dorsally applied force on a flexed wrist.25
Atraumatic ruptures of the LTIL may occur secondary to inflammatory arthritis or ulnar impaction syndrome.18
NATURAL HISTORY
Tears of the SLIL or LTIL, with or without extrinsic ligamentous injury, may lead to various degrees of carpal instability (predynamic, dynamic, or static), alteration of normal carpal mechanics and kinematics, and early degenerative changes in the radiocarpal and midcarpal joints.
A complete SLIL tear is associated with the development of a DISI deformity, which may be dynamic or static (indicates additional injury to the extrinsic ligaments).
As a DISI deformity forms, abnormal radiocarpal contact loading occurs as the proximal carpal bones shift in position and lose congruency.
Abnormal flexion and hypermobility of the scaphoid over time leads to degenerative changes of the radioscaphoid and capitolunate joints and ultimately collapse, termed scapholunate advanced collapse (SLAC) wrist degeneration.22,23
These degenerative changes have been documented to begin as early as 3 months after injury.
A complete LTIL tear is associated with the development of a volar intercalated segment instability (VISI) deformity.
The natural history of partial tears of the SLIL or LTIL is at present poorly defined.
Partial scapholunate and LT injuries may cause chronic, activity-related wrist pain in the absence of radiologic findings.23
Predynamic or dynamic instability may cause attenuation of extrinsic ligaments with progressive development of further instability and static changes.29,30
There is evidence that this process typically requires many years.10
PATIENT HISTORY AND PHYSICAL FINDINGS
Dorsoradial or ulnar-sided wrist pain with a history of a fall, sudden loading, or twisting of the wrist should raise suspicion for a SLIL or LTIL tear, respectively. However, it is not uncommon for the patient to deny any significant injury.
Patients frequently complain of weakness, swelling, and loss of range of motion of the wrist.
A sensation of instability or “giving way” is often reported, occasionally associated with a painful clunk.
A detailed physical examination of the wrist may provide significant information for the diagnosis of ligamentous injuries and help to rule out other wrist pathology.
Examination of the wrist begins with evaluation for any deformity or swelling and determination of wrist range of motion.
Key tests and maneuvers specifically evaluating the scapholunate and lunotriquetral ligaments are as follows:
Grip strength and pain: Diminished grip strength correlates with wrist pathology.
The presence of pain at the central aspect of the wrist with attempted grip has also been associated with scapholunate ligament pathology.
Deep palpation of scapholunate interval: Point tenderness indicates SLIL injury, scaphoid injury, or ganglion cyst.
Watson’s scaphoid shift test: Pain with or without a clunk or catch sensation is highly suggestive of scapholunate instability.
Scaphoid ballottement test: Pain and increased anteroposterior laxity are highly suggestive of scapholunate instability.
Deep palpation of lunotriquetral interval: Point tenderness indicates LTIL injury or triangular fibrocartilage complex (TFCC) pathology.
Ulnar wrist loading: A painful snap indicates lunotriquetral instability, midcarpal instability, or TFCC complex pathology. This maneuver will also be painful if ulnar impaction is present.
Triquetrum ballottement test: Pain and increased anteroposterior laxity are highly suggestive of lunotriquetral instability.
“Ulnar snuffbox” tenderness: Pain with or without crepitus indicates lunotriquetral instability, TFCC complex pathology, or triquetrohamate pathology.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Initial imaging of the wrist should always include AP and lateral radiographs, combined with special views depending on the suspected pathology. If scapholunate pathology is suspected, a bilateral pronated grip anteroposterior (Mayo Clinic) view should be obtained for comparison to the contralateral side.
Abnormal findings in static scapholunate instability include:
AP view: increased scapholunate interval (3 mm or more; comparison to contralateral wrist), scaphoid cortical “ring sign,” and triangular appearance of lunate
Lateral view: flexion of scaphoid and dorsiflexion of lunate, as determined by increased scapholunate angle (more than 60 degrees) and increased lunocapitate angle (over 10 degrees) with dorsal translation of capitate
Radiographic findings in patients with lunotriquetral tears are often normal. Abnormal findings in static lunotriquetral instability include:
AP view: proximal translation of triquetrum or lunotriquetral overlap without gapping, and interruption of Gilula’s arc
Lateral view: flexion of scaphoid and lunate, as determined by normal or decreased scapholunate angle (less than 45 degrees), increased lunocapitate angle (more than 10 degrees) with volar translation of capitate, and a negative lunotriquetral angle
Provocative views (radial-ulnar deviation, flexion–extension views) or videofluoroscopy may demonstrate asynchronous scapholunate motion (dynamic scapholunate instability) in cases with suspected SLIL injury and normal standard views. Increased, synchronous mobility of the scapholunate complex with diminished motion of the triquetrum indicate an LTIL injury.
Wrist arthrography has a sensitivity of only 60% compared to arthroscopy and cannot determine the extent of any tear present.26
MRI (with or without arthrography) has limited value in evaluating interosseous ligament injuries. Reported sensitivity rates for SLIL injuries range from 40% to 65% compared to arthroscopy.17 MRI is even less reliable in diagnosing LTIL injuries.
Arthroscopy (radiocarpal, midcarpal with probing) remains the gold standard in evaluation of SLIL and LTIL injuries.
DIFFERENTIAL DIAGNOSIS
Differential diagnosis of scapholunate injuries and radialsided wrist pain21
Scaphoid fracture or nonunion
Scaphotrapezial arthritis
Radiocarpal arthritis
De Quervain’s tenosynovitis
Dorsal ganglion cyst
Dorsal wrist impaction syndrome
Perilunate instability
Isolated DRC ligament tear
Differential diagnosis of lunotriquetral injuries and ulnarsided wrist pain18
TFCC injury
Distal radioulnar joint (DRUJ) instability or arthritis
Ulnar impaction syndrome or chondromalacia
Ulnar styloid impingement syndrome
Extensor carpi ulnaris (ECU) tendon subluxation
Pisotriquetral arthritis
Triquetrohamate instability
Hamate fracture
Ulnar neurovascular syndromes
NONOPERATIVE MANAGEMENT
SLIL and lunotriquetral injuries associated with dynamic instability may respond to initial nonoperative treatment for 6 to 12 weeks.
Conservative management typically includes a combination of the following:
Splinting
Nonsteroidal anti-inflammatories
Intra-articular (radiocarpal) corticosteroid injections
Occupational therapy and work restrictions
Re-education of wrist proprioception with flexor carpi radialis strengthening
SURGICAL MANAGEMENT
The selection of surgical treatment for SLIL and LTIL injuries is based on the severity of symptoms, the degree of instability (dynamic or static), chronicity (acute, subacute, or chronic), arthroscopic findings (Geissler grade; see TECH FIG 1), and reparability of the ligament.
Dynamic instability (based on positive physical findings with provocative maneuvers, abnormal stress radiographs, arthroscopic findings) that has failed to respond to nonoperative treatment may be treated arthroscopically.
Arthroscopic options include simple débridement, débridement with thermal shrinkage, and débridement (with or without shrinkage) with percutaneous pinning.
Static instability and severe dynamic instability are indications for open surgery.
Surgical options include open repair or augmentation (especially of acute or subacute injuries), capsulodesis, and tenodesis.
Patients developing carpal collapse with arthritic changes require salvage procedures such as radial styloidectomy, proximal row carpectomy, and limited wrist fusions (eg, STT, scaphocapitate, scaphoidectomy plus four-corner fusion, reduction-association scapholunate [RASL] procedure, lunotriquetral fusion).
The focus of this chapter is on arthroscopic procedures described for management of dynamic scapholunate or lunotriquetral instability. Newer arthroscopic alternatives advocated for management of more advanced pathology are also described.
Arthroscopic Procedures
Arthroscopic débridement of SLIL and LTIL injuries
Indications: Predynamic or dynamic instability; arthroscopic findings of a partial ligament tear with an unstable tissue flap (Geissler grade II); with or without synovitis15,27
The ideal patient for this technique is one with mechanical symptoms (pain with crepitance or clicking) attributable to impingement of unstable tissue flaps and resulting synovitis.
Arthroscopic débridement and thermal shrinkage of SLIL and LTIL disruptions
Indications: Predynamic or dynamic instability; arthroscopic finding of a partial ligament tear (Geissler grade I or II).5,7 The dorsal segment of the SLIL should be intact for this procedure.
This technique provides an option for the management of lax, redundant ligaments with no frank tear (Geissler grade I) where simple débridement is not an option.
Thermal shrinkage is performed in an attempt to increase stability and improve long-term outcome compared to simple débridement.
Radiofrequency probes use a high-frequency alternating current to generate heat. This leads to denaturation (uncoiling) of the collagen triple helix with reduction in overall ligament length.
Use of this device is contraindicated in patients with pacemakers or other implantable electronic devices.
Arthroscopic débridement and percutaneous pinning of SLIL and LTIL disruptions
Indications: Acute or subacute dynamic instability (Geissler grades II and III)3,28
This technique aims to induce the formation of fibrous union between the two involved carpal bones.
Arthroscopic radial styloidectomy
Indications: Early (stage I) scapholunate advanced collapse (SLAC) wrist (ie, radial styloid–scaphoid impingement or arthritis) with focal and reproducible clinical findings of radial styloid pain exacerbated by wrist flexion and radial deviation
This procedure may provide significant pain relief until a salvage procedure (proximal row carpectomy, scaphoid excision, four-corner fusion) becomes necessary.
Arthroscopic RASL procedure (see Chap. HA-46) and lunotriquetral fusion
Indications: Static instability (Geissler grade IV); lunotriquetral arthritis13,14
Early (stage I) SLAC wrist is not a contraindication.
The RASL procedure aims to achieve fibrous union while maintaining mild rotation at the scapholunate joint, thus approximating normal wrist kinematics. On the other hand, bony fusion is the goal in the lunotriquetral joint.
Preoperative Planning
A careful review of the patient’s history, physical findings, as well as static and stress radiographs may provide the surgeon with a reasonable impression of what will be required.
In most cases, however, a decision on the type of procedure to be performed is made intraoperatively based on the arthroscopic findings and associated pathology.
Consideration must therefore be given to have the following available: radiofrequency probes, mini C-arm, drills, Kirschner wires of various widths, and headless compression screws.
Positioning
The patient is placed in the supine position with the extremity on a hand table.
Any possible donor site for ligament reconstruction or augmentation should also be prepared and draped in a sterile fashion.
The extremity is placed in a tower distraction device with 10 to 12 lb (5 to 6 kg) of distraction and 12 to 15 degrees of wrist flexion (FIG 1).
The arthroscope monitor is placed on the opposite side of the hand table from the surgeon.
FIG 1 • A. Positioning for arthroscopy of the wrist. B. The monitor should be visible to the surgeon. If use of fluoroscopy is anticipated, the C-arm is placed adjacent to the head of the operating table.
If percutaneous pinning or use of other implants is anticipated, a small fluoroscopy unit is placed adjacent to the head of the operating table.
Approach
Arthroscopic evaluation and management of scapholunate and lunotriquetral injuries can typically be performed through standard dorsal wrist portals (3–4, 4–5, 6R, midcarpal).
The additional use of a radial volar portal through the flexor carpi radialis (FCR) sheath has been advocated for better visualization of the volar portions of the SLIL and LTIL, as well as the DRC and DIC ligaments.1,19
TECHNIQUES
ARTHROSCOPIC EVALUATION
An 18-gauge needle is used to distend the radiocarpal joint with 7 to 10 mL of normal saline.
A 2.7-mm, 30-degree arthroscope is preferred for wrist arthroscopy.
Typical working portals include the 3–4, 4–5, 6R, and midcarpal portals. Outflow is established through the 6U or 6R portal.
The entire radiocarpal joint is evaluated in a systematic manner, usually from radial to ulnar.
The SLIL is best visualized through the 3–4 portal with probe insertion through the 4–5 or 6R portal. The 4–5 portal is used for instrumentation.
Occasionally the avulsed portion of the SLIL may make visualization through the 3–4 portal difficult. In this situation, the arthroscope is transferred to the 6R portal and directed radially.
The proximal portion of the SLIL is easily visualized by following the radioscapholunate ligament (ligament of Testut) to its insertion. The volar radioscapholunate and long radiolunate ligaments (wider) are visualized radially, and the short radiolunate is located ulnar to the ligament of Testut.
TECH FIG 1 • Geissler arthroscopic classification of interosseous ligament injuries of the wrist. The scapholunate joint is depicted here but the classification is also applicable to the lunotriquetral joint. A.Grade I: Attenuation of the scapholunate interosseous ligament as visualized in the radiocarpal joint. No incongruence is noted in the midcarpal joint. B. Grade II: Partial full-thickness tear with unstable flap but minimal joint incongruity. C. Grade III: Complete tear of the scapholunate interosseous ligament with moderate joint incongruity. A 1.5-mm probe can enter the joint (view from midcarpal portal). D.Grade IV: Complete tear with marked incongruity. The 2.7-mm arthroscope can “drive through” the joint.
The LTIL is best visualized through the 4–5 or 6R portal, with use of the 3–4 and 6R for instrumentation.
Both ligaments should be evaluated in their entirety (dorsal, proximal, and volar portions).
If visualization of the volar portions of the SLIL and LTIL is inadequate, an additional volar portal through the FCR sheath may be used,1 but this has rarely been necessary in our experience.
In patients with gross scapholunate instability, the arthroscope is finally turned toward the dorsum of the scaphoid and lunate to identify possible avulsion of the DIC or DRC ligament.16
Evaluation of carpal congruence and stability is incomplete without performance of midcarpal arthroscopy.
The midcarpal portals are placed 1 cm distal to the 3–4 and 4–5 portals.
The 2.7-mm, 30-degree arthroscope is aimed proximal.
The scapholunate joint is visualized radially and the lunotriquetral joint ulnarly.
Both joints are evaluated for congruity.
Stability is evaluated with a 1-mm arthroscopic probe and the 2.7-mm arthroscope.
A Watson scaphoid shift test may be performed while visualizing the scapholunate joint.
The Geissler arthroscopic classification of wrist interosseous ligament tears is shown in Techniques Figure 1.5
ARTHROSCOPIC DÉBRIDEMENT
A thorough diagnostic arthroscopy (radiocarpal plus midcarpal) is performed to verify the diagnosis and rule out instability or other associated pathology.
The inflamed synovium is excised with a 2.5 or 2.7-mm full-radius resector.
Any unstable tissue flaps are resected with a suction punch or synovial resector.
Redundant tissue is then resected to a stable rim with the synovial resector or bipolar radiofrequency probe.
A probe is then inserted through the 4–5 or 6R portal to reassess stability from both the radiocarpal and midcarpal joint.
Débridement should generally be limited to the proximal membranous portion of the SLIL or LTIL.
Unwarranted débridement of the dorsal (SLIL) or volar (LTIL) portions of the ligamentous complex may lead to further instability.
Carpal stability should be assessed both before and after débridement.
ARTHROSCOPIC DÉBRIDEMENT AND THERMAL SHRINKAGE
Diagnostic arthroscopy is performed as previously described.
Geissler grade II tears are débrided with a synovial resector to a stable rim (TECH FIG 2A). Thermal shrinkage of the intact portion of the ligament is then performed with a 2.3-mm bipolar radiofrequency probe.
Attenuated ligaments (Geissler grade I) are treated with thermal shrinkage alone.
Thermal shrinkage is performed by applying the radiofrequency probe in a paintbrush fashion (2.3-mm radiofrequency probe [Mitek VAPR®, Westwood, MA]) (TECH FIG 2B). The goal is to evenly distribute the thermal energy throughout the ligament.
The 4–5 portal is preferred for this procedure for optimal access to the SLIL.
Ligament shrinkage is visually confirmed by a change in its color and consistency (TECH FIG 2C).
Intermittent application of the probe (a few seconds at a time) with adequate outflow prevents ablation of the ligament and overheating of the joint.
Radiofrequency probes specially designed for thermal shrinkage have recently become available. They offer additional safety by not reaching ablation temperature.
TECH FIG 2 • Débridement and thermal shrinkage. A. Geissler grade II scapholunate interosseous ligament tear as seen through 3–4 portal. B. “Paintbrush” technique for thermal shrinkage. The probe is applied intermittently to avoid overheating. C. The same ligament after débridement and thermal shrinkage. Note apparent change in color and consistency.
ARTHROSCOPIC DÉBRIDEMENT AND PERCUTANEOUS PINNING
Diagnostic arthroscopy is performed as previously described.
All residual tissue of the torn ligament (SLIL or LTIL) is debrided with a 2.5 or 2.7-mm full-radius resector.
The cartilage of the apposing surfaces of the involved carpal bones is then débrided to bleeding bone with a 2.5 or 2.7-mm aggressive full-radius resector and a 2.9-mm barrel abrader (TECH FIG 3A).
The extremity is then removed from the distraction tower.
If necessary, congruity of the joint is improved by external (pressure on the distal pole of scaphoid) or internal maneuvers (percutaneous Kirschner wires used as joysticks).
The joint is stabilized by percutaneously inserting three or four 0.045-inch (1.1-mm) Kirschner wires under fluoroscopic control.
The scapholunate joint is typically stabilized with two Kirschner wires across the scapholunate joint (radial to ulnar) followed by one or two Kirschner wires across the scaphocapitate joint (TECH FIG 3B).
The lunotriquetral joint is similarly stabilized with two Kirschner wires across the lunotriquetral joint (ulnar to radial) followed by one or two Kirschner wires across the lunocapitate joint.
The pins are then cut subcutaneously or bent outside the skin per surgeon preference.
TECH FIG 3 • Débridement and percutaneous pinning. A. Remnants of ligament and articular cartilage of apposing surfaces are débrided to bleeding bone. B. The joint is stabilized with three or four Kirschner wires placed under fluoroscopic guidance.
ARTHROSCOPIC RADIAL STYLOIDECTOMY
Diagnostic arthroscopy is initially performed to delineate the chondral lesions and accurately stage the SLAC wrist.22
The arthroscope is placed in the 3–4 or 4–5 portal.
Excision of the radial styloid is performed through the 1–2 (or 3–4) portal with a side-cutting 3.5-mm sheathed burr.
Arthroscopic evaluation of articular cartilage and intraoperative radiographs should be used to determine the extent of resection.
The origin of the radioscaphocapitate ligament is visualized and preserved during bone resection.
Although the tendency is to overestimate the amount of bone resected, excision of more than 4 mm may jeopardize the ligament and result in ulnar carpal dislocation.
ARTHROSCOPIC RASL PROCEDURE AND LUNOTRIQUETRAL FUSION
Diagnostic arthroscopy with evaluation of chondral lesions is performed as described previously.
The apposing surfaces of the joint to be fused are débrided to bleeding bone with a 2.5 or 2.7-mm aggressive full-radius resector and a 2.9-mm barrel abrader.
Complete decortication is verified from both the radiocarpal and midcarpal joints.
In the case of the RASL procedure, a side-cutting 3.5-mm sheathed burr is then used to perform an arthroscopic radial styloidectomy through the 1–2 (or 3–4) portal as described previously.
Kirschner wires (0.062 inch or 1.6 mm) are then inserted percutaneously from the dorsum into the involved carpal bones (distal scaphoid-lunate or lunate-triquetrum). Positioning of the wires should be slightly eccentric to allow for subsequent placement of the screw centrally. The Kirschner wires are used as joysticks to reduce the joint under fluoroscopic (with or without arthroscopic) control.
It is essential to verify adequate reduction of the capitolunate joint on the lateral view.
A Köcher clamp may be placed across the Kirschner wires to maintain reduction.
An additional 0.045-inch (1.1-mm) Kirschner wire may be inserted through the dorsal rim of the distal radius into the lunate for provisional stabilization of the lunate.
A 0.035-inch (0.9-mm) guidewire is then placed across the joint (scapholunate or lunotriquetral) under fluoroscopic control.
In the case of the RASL procedure, the guidewire should be placed through the 1–2 portal, across the scaphoid waist toward the proximal-ulnar corner of the lunate, thus approximating the normal axis of rotation of the scapholunate joint (TECH FIG 4).
A cannulated headless compression screw is then placed across the joint. Length measurement should be reduced by about 4 mm to accommodate for joint compression and to ensure that the screw is completely countersunk into bone.
After satisfactory reduction and fixation are verified, the wrist capsule incision is repaired.
In patients with lunotriquetral instability as a result of ulnar impaction syndrome, fusion of the lunotriquetral joint must be combined with an arthroscopic wafer procedure or an ulnar shortening.
TECH FIG 4 • RASL technique. Scapholunate joint reduction is achieved using two Kirschner wires as joysticks. Optimal positioning of a compression screw is through the scaphoid waist toward the proximal-ulnar corner of the lunate, and fully countersunk.
POSTOPERATIVE CARE
Patients treated with arthroscopic débridement alone are placed in a cock-up wrist splint postoperatively and instructed to initiate range-of-motion exercises at 48 hours.
Patients treated with arthroscopic débridement and thermal shrinkage are placed in a full-time short-arm splint postoperatively. Range-of-motion exercises are initiated at 2 to 4 weeks, with use of a removable cock-up splint between sessions. Strengthening exercises are initiated at 4 to 6 weeks.
Patients treated with arthroscopic débridement and percutaneous pinning are placed in a short-arm splint, changed to a short-arm cast after suture removal. The cast is maintained until pin removal, which is performed at 8 to 10 weeks for the scapholunate and at 4 to 6 weeks for the lunotriquetral joint. Range-of-motion exercises are then initiated, with progression to strengthening as tolerated.
Patients treated with an arthroscopic RASL procedure are placed in a short-arm splint for only 2 or 3 weeks. Range-ofmotion exercises are then initiated, with progression to strengthening as tolerated. Conversely, patients treated with arthroscopic fusion of the lunotriquetral joint are immobilized until radiographic fusion is obtained.
OUTCOMES
Ruch and Poehling15 reported excellent results with arthroscopic débridement alone in 14 patients with partial SLIL or lunotriquetral tears, or both, and predominantly mechanical symptoms. At a minimum follow-up of 2 years, all patients reported complete relief of their mechanical symptoms, while pain was significantly reduced and grip strength was restored.
Weiss et al27 have treated both partial and complete SLIL and lunotriquetral tears with arthroscopic débridement alone in an attempt to elicit scar formation with some degree of stabilization. Excellent pain relief and increased strength were achieved in 17 of 19 patients with partial tears, but only in 17 of 24 patients with complete tears. No radiologic progression was noted at 27 months follow-up.
Darlis et al4 reported substantial pain relief in 14 of 16 patients with Geissler grade I or II SLIL tears treated with arthroscopic débridement and thermal shrinkage. Wrist motion was maintained and there was no radiologic evidence of instability at 19 months of follow-up.
Hirsh et al6 reported excellent results in 9 of 10 patients with Geissler grade II SLIL tears treated with arthroscopic débridement and thermal shrinkage at 28 months of follow-up.
Whipple28 reported his results with percutaneous pinning in patients with scapholunate instability. Symptom duration of more than 3 months and a side-to-side gap difference of more than 3 mm were associated with poor outcomes. Pain relief was satisfactory in only 53% of patients with both of these factors.
Darlis et al3 reported management of chronic (longer than 3 months) dynamic scapholunate instability (Geissler grades III, IV) with arthroscopic débridement and percutaneous pinning in patients who did not wish to undergo open surgery. Results were suboptimal, with significant pain relief and improved grip strength in 6 of 11 patients. At 33 months of follow-up there was no radiologic evidence of progression to static instability, but three patients required additional surgery to address persistent pain.
Clinical experience with the arthroscopic RASL procedure and lunotriquetral fusion is limited. Rosenwasser et al14reported excellent results using the open RASL technique in 20 patients with static instability. At 54 months of follow-up, patients had achieved 91% of their normal wrist motion and 87% of contralateral grip strength. The authors noted that the procedure may be performed arthroscopically, but thought that experience with the open technique should first be obtained.
COMPLICATIONS
Injury to branches of superficial radial sensory nerve (especially with use of 1–2 portal) or dorsal branch of ulnar nerve (6R, 6U portals)
Injury to radial artery (radial volar portal). This portal should be established through the floor of the FCR sheath.
Persistent pain or instability
Need for additional surgery (ligament reconstruction, capsulodesis, tenodesis, proximal row carpectomy, partial or complete wrist fusion)
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