W R I S T I N S T A B I L I T Y A N D A R T H R O S C O P Y 402 often detached from the dorsal aspect of the lunate. The proximal wrist and mid- carpal joints are examined through the capsular incisions for any osteochondral or chondral lesions. Any free fragments are excised. A trial reduction of the scapholu- nate joint is performed manually, and, if there is any difficulty in obtaining the re- duction, 0.062-inch-diameter Kirschner wires (K wires) can be placed dorsally in the scaphoid and in the lunate and used as “joysticks” to assist in the reduction. While maintaining the scapholunate reduction, 0.045-inch-diameter K wires are used to percutaneously pin the scapholunate joint both from the radial and from the ulnar sides to maintain the reduction. Once the scapholunate joint has been pinned, radiographs are obtained to con- firm the reduction in both AP and lateral projections. Once the reduction has been confirmed radiographically, a 2.0- or 2.5-mm suture anchor is placed in the dorsal rim of the proximal half of the scaphoid in the area where the dorsal segment of the scapholunate interosseous ligament and the DIC ligament have been avulsed. An- other suture anchor is placed at the dorsal aspect of the lunate, if the DIC ligament has been avulsed off the lunate (Fig. 63–2A). The suture attached to the scaphoid suture anchor is utilized to reattach the dSLIL and the DIC to their origin on the scaphoid. The suture attached to the lunate suture anchor is utilized to reattach the DIC to its origin on the lunate. If the injury is chronic, and the DIC has contracted and lies distal to its normal location, then the DIC is released distally while main- taining its triquetral attachment and is relocated and attached to the lunate and scaphoid. Once these sutures are tied, the same sutures are used to repair the capsu- lar incision with a slight vest-over-pants imbrication (Fig. 63–2B). Reattachment of the proximal membranous portion of the scapholunate in- terosseous ligament has also been described. This portion of the ligament, however, is often seen to be disrupted or attenuated in several cadaver dissections. Mechani- cally, it is not as substantial as the dorsal portion of the scapholunate interosseous ligament complex or the DIC ligament and is an intraarticular structure bathed in synovial fluid with questionable potential for healing. In addition, the degree of fur- dSLIL S T L R U DIC Dorsal capsule DIC dSLIL Radius Scaphoid A B Figure 63–2. (A) Placement of the scaphoid and lunate suture anchors to repair the dorsal intercarpal (DIC) ligament, which is most commonly avulsed off the lunate and the scaphoid, and the dorsal component of the scapholunate interosseous ligament (dSLIL), which is usually avulsed off the scaphoid. (B) Lateral view of a scaphoid illustrating the suture anchor in place. The same suture is utilized first to anchor the dSLIL and the DIC ligaments to the scaphoid, then to repair the capsule in a slight vest over pants fashion. S, scaphoid; L, lunate; T, triquetrum; R, radius, U, ulna. S C A P H O L U N A T E I N S T A B I L I T Y 403 ther dissection of the scaphoid to place the drill holes and sutures for reattachment of the membranous portion of the scapholunate interosseous ligament is more sub- stantial and of questionable benefit. Postoperative Management The wrist and forearm are immobilized in a long-arm splint with the forearm in slight pronation for 4 weeks. The wrist is then immobilized in a short-arm splint for an additional 8 weeks. Radiographs are obtained postoperatively at 1, 2, and 4 weeks to assess carpal alignment and pin position. The skin sutures are removed at 2 weeks. Any signs of pin tract inflammation and/or drainage should be treated with suppressive antibiotics until pin removal. The pins are removed at l2 weeks, the wrist is placed in a removable short-arm volar splint, and gentle active range-of- motion exercises are begun (Fig. 63–3). There is a postimmobilization period of stiffness that either the activities of daily living or the addition of formal therapy will resolve over a 3- to 6-month period. Suggested Readings Berger RA, Amadio PC, Imadea T, An KN, Cooney WP. The gross and histologic anatomy and material properties of the subregions of the scapholunate ligament. A B Figure 63–3. AP clenched fist (A) and lateral (B) radiographs of the wrist of the patient in Figure 63–1, 2 years following his surgical repair/reattachment of the DIC and the dSLIL. W R I S T I N S T A B I L I T Y A N D A R T H R O S C O P Y 404 Paper presented at: NATO Advanced Research Workshop, Advances in the Biome- chanics of the Hand and Wrist; May 22–23, 1992; Brussels, Belgium. Lavernia CJ, Cohen MS, Taleisnik J. Treatment of scapholunate dissociation by lig- amentous repair and capsulodesis. J Hand Surg [Am] 1992;17A:354–359. Metz VM, Schimmerl SM, Gilula LA, Viegas SF, Saffar P. Wide scapholunate joint space in lunotriquetral coalition: a normal variant? Radiology 1993;188:557–559. Viegas SF, Patterson RM, Hokanson JA, Davis J. Wrist anatomy: incidence, distri- bution and correlation of anatomy, tears and arthritis. J Hand Surg [Am] 1993;18A: 463–475. Viegas SF, Yamaguchi S, Boyd NL, Patterson RM. The dorsal ligaments of the wrist: anatomy, mechanical properties and function. J Hand Surg [Am] 1999;24A: 456–468. Watson HK, Ashmead D IV, Makhlouf MV. Examination of the scaphoid. J Hand Surg [Am] 1988;13A:657–660. Whipple TL. The role of arthroscopy in the treatment of scapholunate instability. Hand Clin 1995;11:37–40. L U N O T R I Q U E T R A L I N S T A B I L I T Y 405 PEARLS • A standardized PA wrist radi- ograph yields useful informa- tion about ulna variance and impaction. • LT and TFCC pathology often coexist. • Dynamic imaging is useful to confirm the presence of LT pathology. PITFALLS • Beware of false-positive and false-negative arthrograms. Clinical correlation is required. • Viewing the LT articulation from the midcarpal joint is important to exclude nondis- sociative midcarpal instability. 64 Lunotriquetral Instability Loryn P. Weinstein and Allen T. Bishop His tory and Clinical Presentation A 48-year-old right hand dominant mechanic presented for evaluation of right ulnar-sided wrist pain. Two weeks earlier he had slipped in his shop and landed on a dorsiflexed wrist. The primary impact was to the hypothenar eminence. Subse- quently, he developed intermittent ulnar-sided wrist pain, exacerbated by radial- ulnar deviation. Grip strength was diminished, and he felt his wrist give way when torquing heavy tools. These symptoms reduced his work productivity and pre- vented him from participating in his weekly bowling league. Phy sical Examin ation No wrist swelling or obvious deformity was noted. There was point tenderness dor- sally over the triquetrum. Range of motion was diminished in all planes. A painful clunk was palpable with radial-ulnar deviation. Compression of the triquetrum with a radially directed force elicited pain. Excessive laxity was present with luno- triquetral (LT) ballottement when compared with the contralateral wrist. Grip strength was reduced 20% compared with the contralateral, nondominant side. He was neurovascularly intact. Dia gnostic Studies Anteroposterior, lateral, and oblique radiographs of the wrist were normal. An arthrogram was obtained (Fig. 64–1). Relative malalignment between the lunate and the triquetrum may be apparent on lateral radiographs. Bisectors of the lunate and triquetrum intersect to form an LT angle (normal = 14 degrees, range Ϫ3 to +31 degrees). Patients with LT dissoci- ation will exhibit a negative angle (mean value = Ϫ16 degrees). A volar intercalated segmental instability (VISI) pattern is present in some (chronic) cases. Radial deviation and clenched-fist anteroposterior views can be useful. Palmar flexion of the scaphoid and lunate without movement of the triquetrum confirms the loss of proximal row integrity. Arthrography is a useful imaging tool for LT instability. Passage of dye through the LT interspace documents the presence of a perforation, tear, or dissociation. Age-related LT perforations and tears have been frequently demonstrated in asymp- tomatic individuals. Therefore, arthrogram findings require clinical correlation. A videotaped arthrogram with motion sequences demonstrating abnormal dye pool- ing associated with abnormal proximal row kinetics is useful as a confirmatory study. Bone scans, tomograms, and magnetic resonance imaging (MRI) have limited utility in the setting of LT instability. Standards for MRI of LT ligaments are not yet available. W R I S T I N S T A B I L I T Y A N D A R T H R O S C O P Y 406 Figure 64–1. Patient arthro- gram. Dif ferential Diagnosis Nondissociative midcarpal instability Lunotriquetral instability Ulnar impaction syndrome Triangular fibrocartilage complex (TFCC) injury Pisotriquetral injury Extensor carpi ulnaris (ECU) subluxation The differential diagnosis of ulnar-sided wrist pain is broad (Table 64–1). How- ever, a history of a specific injury with subsequent instability and “clunking” during radial-ulnar deviation suggests relatively few diagnoses. These include LT instabil- Table 64–1 Differential Diagnosis Diagnosis Differentiating Findings Triquetrohamate instability Antecedent trauma, hyperextension mechanism TFCC tear Painful radial-ulnar deviation and clunk Ulna impaction syndrome Focal tenderness Pisotriquetral injury Positive LT provocative tests ECU instability Positive radiograph findings Positive arthrogram or arthroscopic exam L U N O T R I Q U E T R A L I N S T A B I L I T Y 407 ity, nondissociative midcarpal instability, TFCC injury, ulnar impaction syndrome, pisotriquetral injury, and ECU subluxation. Midcarpal instability often produces a painful clunk with ulnar deviation, but antecedent trauma is rarely reported. Provocative LT maneuvers are negative. A “catch-up clunk” may be demonstrable during motion of a loaded wrist from a ra- dial to an ulnar deviated position, resulting in a sudden extension of the lunate and scaphoid in this condition as joint contact forces them to “catch up” to the already extended triquetrum. Cineradiography is useful to examine the synchronicity of proximal row kinetics to differentiate midcarpal from LT instability, the latter demonstrating the “clunk” arising from sudden extension of the scaphoid and lu- nate alone during ulnar deviation, dissociated from the triquetrum. TFCC tears can mimic LT instability with an analogous injury history and symp- tomatic clicking. Provocative LT tests are negative, whereas distal radioulnar joint (DRUJ) and TFCC provocative tests are positive. In some cases, coincident LT and TFCC pathology is demonstrated by arthrography or arthroscopy. Isolated TFCC injury is best visualized by MRI or arthroscopy. Ulnocarpal impaction syndrome is the result of excessive ulnar positive variance. Pain and weakness with rotational motion are noted. A standard neutral postero- anterior (PA) wrist radiograph will demonstrate ulna positive variance and “kissing” degenerative cysts and sclerosis at the lunate and ulna head. LT and TFCC tears are frequently associated findings. Arthrography or arthroscopy can assess LT and TFCC integrity prior to undertaking an ulnar shortening procedure. A pisiform fracture may present after acute hypothenar trauma. This is best visual- ized with a supination oblique or carpal tunnel view radiograph. Radial-ulnar devia- tion may be painful, but specific LT provocative tests are negative. Pain and crepitance may be found by pisiform compression and translation. Subluxation of the extensor carpi ulnaris tendon produces an audible snap as the forearm is actively supinated and the wrist is slightly flexed and ulnar deviated. LT provocative maneuvers are negative. Dia gnosis Lunotriquetral Instability Lunotriquetral (LT) instability results from a disruption of the dorsal and palmar LT interosseous complex. A spectrum of pathology is possible, proportional to the magnitude and acuity of ligamentous disruption. Degenerative membrane perfora- tion may be asymptomatic. Partial tears of the LT membrane may produce dynamic instability, and complete ligament dissociation may produce a static VISI pattern. Lunotriquetral instability most commonly follows a specific injury. Hyperex- tension at the wrist is a common mechanism. Weakness and a decreased range of motion are usually present. Pain is precipitated with radial-ulnar deviation, and sometimes a “clunk” is audible. The individual may perceive instability or a giving- way sensation. Ulnar paresthesias are occasionally present. Point tenderness is localized to the LT junction. A painful clunk may be palpable with radial-ulnar deviation. Diminished grip strength and radiocarpal motion are common. Three provocative maneuvers for LT instability have been described: the compres- sion, ballottement, and shear tests. Compression of the triquetrum in the ulnar snuffbox using a radially directed force may elicit pain, suggesting LT or triquetrohamate pathol- ogy. Ballottement of the LT ligament is performed by grasping the pisotriquetral unit W R I S T I N S T A B I L I T Y A N D A R T H R O S C O P Y 408 Figure 64–2. Demonstration of shear test, with the exam- iner’s contralateral thumb placed dorsally over the lunate as the ipsilateral thumb loads the pisotriquetral joint from the palmar side. between the thumb and index finger of one hand and the lunate between the thumb and index of the other. An anteroposterior translation motion is performed between these bones. Pain and dorsal palmar laxity greater than that on the opposite side signify a pos- itive test. The shear test is performed with the elbow supported on the hand table and the forearm in neutral rotation. The examiner’s contralateral thumb is placed dorsally over the lunate as the ipsilateral thumb loads the pisotriquetral joint from the palmar side (Fig. 64–2). The test is positive when pain, crepitance, or abnormal LT mobility is elicited. Comparison with the contralateral wrist is important for all provocative tests. A variety of imaging studies can support a diagnosis of LT instability. Standard anteroposterior radiographs may be normal in partial tears. Findings in complete dissociation include disruption of Gilula’s arcs, proximal triquetral translation, and LT overlap. Unlike scapholunate dissociation, a widening of the interosseous inter- val is not visualized. Positive ulnar variance should be noted. When present, it may be the cause of an attritional LT tear and require treatment. Arthroscopy has both a diagnostic and therapeutic role. Direct inspection and palpation of the LT ligament, TFCC, capsular structures, and articular surfaces al- lows accurate diagnosis of LT pathology. Midcarpal arthroscopy is important for the assessment of LT stability. Nonsurgical Man agement Treatment is based on the severity and chronicity of injury. Initial management of acute LT tears (partial membrane injuries) consists of cast immobilization, which L U N O T R I Q U E T R A L I N S T A B I L I T Y 409 incorporates supplemental padding under the pisiform. Partial LT injuries may heal in this fashion. Symptomatic chronic tears and all dissociations (complete mem- brane disruptions), regardless of chronicity, are best managed surgically. Surgical Management Lunotriquetral stability can be restored by ligament repair, reconstruction, or arthrode- sis. Additional procedures may be necessary if significant ulnar variance or arthrosis is present. Ligament repair is a technically demanding procedure. A dorsal approach be- tween the fourth and fifth compartments and a transverse capsulotomy distal to the TFCC exposes the LT articulation. The remaining LT ligament is typically adherent to the lunate. The radial border of the triquetrum is freshened and three or four parallel drill holes are placed in an ulnar to radial direction. Nonabsorbable suture is passed through the drill holes, anchored to the LT remnant, and passed back through the holes. The joint is reduced and fixed with Kirschner wires (K wires). Proper alignment is confirmed radiographically before the sutures are tied. The su- tures are then tightened. The dorsal radiotriquetral ligament may be advanced and tightened during closure for augmentation. Eight weeks of cast immobilization and 4 weeks of splint immobilization is recommended postoperatively. Reconstruction can be performed when insufficient LT ligament is available for primary repair (Fig. 64–3). A distally based strip of ECU or flexor carpi ulnaris (FCU) is harvested. Static deformity should be reduced and provisionally fixed be- fore preparation for the lunate and triquetrum tunnels. A K wire is drilled from the dorsal ulnar corner of the triquetrum to the volar radial corner of the LT joint. A second K wire is placed in the lunate from its mid-dorsal radial border to exit at the same place in the LT joint. After radiographic confirmation, the holes are serially enlarged with awls. The tendon graft is then passed through the triquetrum and the lunate. The LT joint is percutaneously pinned and again confirmed radiographically Figure 64–3. Illustration of lunotriquetral (LT) recon- struction. W R I S T I N S T A B I L I T Y A N D A R T H R O S C O P Y 410 before the free tendon edge is tensioned and sutured back onto itself. Postoperative immobilization is similar to that for ligament repair. Arthrodesis of the LT joint is performed through a dorsal ulnar approach. After the joint surfaces are decorticated, an intercalary corticocancellous graft is inserted to prevent narrowing of the midcarpal joint. Provisional K-wire fixation and radi- ographic confirmation precede definitive fixation with a compression screw. High nonunion rates are reported with K wires alone or conventional cortical screws. A scaphoid screw is recommended. Controversial point: LT arthrodesis is technically less demanding than ligament re- pair or reconstruction. Reports demonstrate problems with delayed union, non- union, impaired radiocarpal motion, and ulnocarpal abutment. A 20-year series from our institution recently demonstrated better survivorship with ligament repair and reconstruction methods. Suggested Readings Beckenbaugh RD. Accurate evaluation and management of the painful wrist fol- lowing injury. An approach to carpal instability. Orthop Clin North Am 1984;15: 289–306. Bishop AT, Reagan DS. Lunotriquetral sprains. In: Cooney WP, ed. The Wrist. Diag- nosis and Operative Treatment. Chicago: Mosby; 1998. Favero KJ, Bishop AT, Lindscheid RL. Lunotriquetral ligament disruption: a com- parative study of methods. Presented at the 46th Annual Meeting of the American Society for Surgery of the Hand, Orlando, FL, 1992. Kleinman WB. Diagnostic exams for ligamentous injuries. American Society for Surgery of the Hand Correspondence Club Newsletter, No. 51, 1985. Reagan DS, Linscheid RL, Dobyns JH. Lunotriquetral sprains. J Hand Surg [Am] 1984;9A:502–514. Shin AY, Battaglia MJ, Bishop AT. Lunotriquetral instability: diagnosis and treat- ment. J Am Acad Orthop Surg 2000;8:170–179. Shin AY, Weinstein LP, Berger RA, Bishop AT. Treatment of isolated injuries of the lunotriquetral ligament. A comparison of arthrodesis, ligament reconstruction and ligament repair. J Bone Joint Surg [Br] 2001;83B:1023–1028. . stabilized and held in a pronated position by the examiner’s left hand. (B) With the pa- tient’s wrist held in neutral deviation, the examiner’s right hand grasps the patient’s right hand and, with. Radiology 1993; 188 :557–559. Viegas SF, Patterson RM, Hokanson JA, Davis J. Wrist anatomy: incidence, distri- bution and correlation of anatomy, tears and arthritis. J Hand Surg [Am] 1993;18A: 463–475. Viegas. ligaments of the wrist: anatomy, mechanical properties and function. J Hand Surg [Am] 1999;24A: 456–4 68. Watson HK, Ashmead D IV, Makhlouf MV. Examination of the scaphoid. J Hand Surg [Am] 1 988 ;13A:657–660. Whipple