The role of the dorsal intercarpal ligament in dynamic and static scapholunate instability

PURPOSE: Scapholunate instability (SLI) is the most common carpal instability. Recent studies have suggested that the dorsal intercarpal (DIC) and the dorsal radiocarpal ligaments play an important role in stabilization of the scaphoid and lunate. Differences between dynamic SLI and static SLI with a dorsal intercalated segment instability (DISI) are clearly described in the clinical literature; however, there has never been a clear explanation of the anatomic differences. This study describes the role of the DIC in the development of dynamic and static SLI with DISI in a cadaver model. METHODS: Five fresh cadavers were studied radiographically and by 3-dimensional digitization. Six increasing stages of instability were developed by sectioning progressively the following structures: the dorsal capsule, the palmar and proximal (membranous) portion of the scapholunate interosseous ligament, the DIC from its insertion on the scaphoid and trapezium, the dorsal scapholunate interosseous ligament from the scaphoid, the DIC ligament from its attachment on the lunate, and the lunotriquetral interosseous ligament. RESULTS: The scaphoid position and the scapholunate gap changed significantly after sectioning the entire scapholunate interosseous ligament and DIC from the scaphoid when a 5-kg load was applied. The lunate position was unchanged in both the loaded and the unloaded conditions. After detaching the DIC from the lunate, both the scaphoid and lunate moved and the scapholunate gap increased significantly in both loaded and unloaded conditions and showed a DISI deformity. CONCLUSIONS: This study describes an anatomic difference between dynamic and static scapholunate instability. Complete disruption of the scapholunate ligament did not result in the development of a static collapse of the lunate. The DIC had an important role in stabilizing the scaphoid and lunate and preventing DISI deformity. This study suggests that in the clinical setting the DIC ligament should be assessed intraoperatively and consideration should be given to repair and/or reconstruction of the DIC ligament attachments to both the scaphoid and the lunate.     

Palmar-divergent dislocation of the scaphoid and the lunate

We describe a patient with palmar-divergent dislocation of the scaphoid and lunate. After successful closed reduction, the scapholunate and lunotriquetral ligaments were sutured through the dorsal approach, and the anterior capsule was sutured through the palmar approach. The scapholunate and lunotriquetral joints were fixed with Kirschner wires for 7 weeks. At the 1-year follow-up, magnetic resonance imaging showed no evidence of avascular necrosis of the scaphoid or lunate, and radiographs showed no evidence of the dorsal and volar intercalated segment instability patterns associated with carpal instability. However, flexion of the scaphoid and a break in Gilula’s line remained. To our knowledge, this is the first report showing treatment of palmar-divergent dislocation of the scaphoid and lunate by suturing the carpal interosseous ligaments.     

Begutachtung der SL- und LT-Band-Schäden

In terms of function, the wrist is a taut ring-like structure with a rotationally balanced lunate bone. The scaphoid and lunate bones as well as the lunate and triquetral bones are all joined by a U-shaped ligament, the three parts of which are strongest at the dorsal scapholunate (SL) ligament and the palmar lunotriquetral (LT) ligament. An SL- or LT-ligament rupture breaks down the ring-like structure. Due to torsional stability in the intercalated segment, DISI (dorsal intercalated segment instability) or PISI (volar intercalated segment instability) occur in the event of rupture of the LT and/or SL ligaments which, if left untreated, progress to carpal collapse. Static instability can be diagnosed radiologically, while diagnosis of dynamic instability requires cinematography, stress X-rays, magnetic resonance imaging or arthroscopy, the latter being the most reliable. The nature of the accident is also important in terms of an expert opinion, since there are only a few mechanisms which lead to rupture of the SL or LT ligaments. SL- and/or LT-ligament tears frequently occur as concomitant injuries in the case of distal radial or perilunar fractures, among other hand injury complexes.     

A kinematic study of luno-triquetral dissociations

An analysis of carpal motion after sectioning the ligamentous support of the luno-triquetral joints was done by use of stereoradiographic methods. The ligaments were sectioned in two stages. In stage I, a complete sectioning of both the dorsal and palmar luno-triquetral ligaments and the interosseous membrane was done. Stage II consisted of further sectioning of both the dorsal radio-triquetral and dorsal scapho-triquetral ligaments. After both stage I and stage II ligament sectioning, all of the intercarpal joints exhibited altered kinematics. The changes were especially marked at the luno-triquetral joint where motion was increased in all planes of wrist motion. The essential lesion in producing a static palmar flexed intercalated segment instability was division of the dorsal radio-triquetral and dorsal scapho-triquetral ligaments in association with the luno-triquetral ligaments and interosseous membrane sectioning.     

Clinical applications of volar portals in wrist arthroscopy

Volar portals for wrist arthroscopy have certain advantages over the standard dorsal portals for visualizing dorsal capsular structures as well as the palmar aspects of the carpal ligaments. The volar radial portal is relatively easy to use and is an ideal portal for evaluation of the dorsal radiocarpal ligament and the palmar aspect of the scapholunate interosseous ligament. The volar midcarpal portal may be considered as an occasional accessory portal for visualizing the palmar aspects of the capitate and hamate in cases of avascular necrosis or osteochondral fractures. The volar ulnar portal is especially useful for the viewing and debridement of palmar tears of the lunotriquetral ligament.     

Volar portals in wrist arthroscopy

Volar portals for wrist arthroscopy have certain advantages over the standard dorsal portals for visualizing dorsal capsular structures as well as the palmar aspects of the carpal ligaments. The volar radial (VR) portal is relatively easy to use and is an ideal portal for evaluation of the dorsal radiocarpal ligament (DRCL) and the palmar aspect of the scapholunate interosseous ligament. The volar midcarpal portal may be considered as an occasional accessory portal for visualizing the palmar aspects of the capitate and hamate in cases of avascular necrosis or osteochondral fractures. The volar ulnar (VU) portal is especially useful for the viewing and debridement of palmar tears of the lunotriquetral ligament. Copyright © 2002 by the American Society for Surgery of the Hand     

Dorsal wrist ligament insertions stabilize the scapholunate interval: cadaver study

This study examined sequential arthroscopic sectioning of volar, interosseous, and dorsal ligaments about the scapholunate complex in cadaver wrists. We attempted to clarify the contributions of the dorsal ligamentous complex to scapholunate instability and carpal collapse. We found that after sequential sectioning of volar ligaments and the scapholunate interosseous ligament, no scapholunate diastasis or excessive scaphoid flexion occurred. After dividing the dorsal intercarpal ligament, scapholunate instability occurred without carpal collapse. With sectioning of the dorsal radiocarpal ligament from the lunate, a dorsal intercalated scapholunate instability deformity ensued. This information may be of value in comprehending the pathogenesis of scapholunate instability and carpal collapse and in devising the rationales for conservative measures and surgical intervention.     

Volar intercalated segment instability as a result of spontaneous rupture of the supporting ligaments of the wrist due to longterm systemic steroid medication

Linscheid and Dobyns (1972), in a classical article on post-traumatic instability of the wrist described two major types of instability, dorsal and volar. The dorsal intercalated segment instability (D.I.S.I.) was the more common and occurred with scapholunate dissociation and displaced scaphoid fractures. The instability occurred in these conditions as a result of the scaphoid losing its ability to support the carpus. They presented five cases of volar intercalated segment instability (V.I.S.I.) of which four were related to congenital ligament laxity and not to traumatic ligament disruption. In the one case of traumatic origin they felt that the capitolunate ligament was ruptured. However, more recent publications by Taleisnik, Prietto (1982) and Reagan, (1984) have proposed that for V.I.S.I. to occur the lunate triquetral interosseous ligament must be disrupted. We report this case as it demonstrates which ligamentous structures are torn for V.I.S.I. to occur. In addition, these ligament disruptions were pathological and occurred spontaneously as a result of longterm systemic steroid medication.     

The Floating Lunate: Arthroscopic Treatment of Simultaneous Complete Tears of the Scapholunate and Lunotriquetral Ligaments

Carpal instabilities continue to be a controversial topic in hand surgery. Accurate diagnosis of the ligament injuries is usually difficult without an arthroscopic evaluation. Few studies have focused on the diagnosis and proper management of simultaneous scapholunate (SL) and lunotriquetral (LT) ligament tears. This is an uncommon injury that leads to marked disability and chronic wrist pain. This is essentially a “floating lunate” and indicates a severe ligamentous lesion. Thirteen patients (six female and seven male) with complete SL and LT tears and with gross arthroscopic dynamic carpal instability were included in the present study. None of the patients showed radiographic evidence of lunate dislocation. One patient presented acutely and was operated on 3 days after the injury. The average time from the initial injury to the arthroscopy for the other 12 patients was 13.5 months (range 1.5–84 months). All patients underwent arthroscopic debridement of the SL and LT ligaments coupled with percutaneous pinning (two 0.045-in. Kirschner wires) in both joints. At the final follow-up, the average range of motion was 50° of flexion, 54° of extension, 77° of pronation, 80° of supination, 25° of ulnar deviation, and 15° of radial deviation. The average final grip strength was 67% from the non-affected side. All patients had negative shifting tests at final follow-up. Furthermore, there was no evidence of any static or dynamic instability in all the patients except for one patient who developed a volar intercalated segment instability 8 months after the surgery. At the final follow-up, ten patients had no pain, one had mild pain, and two experienced moderate pain.     

Thumb collateral ligament injuries. An anatomic basis for treatment

This anatomic and clinical study leads to the following conclusions: 1. The ulnar and radial proper collateral ligaments are the critical lateral stabilizers of the thumb MP joint; both are highly vulnerable to complete disruption, with resultant disabling joint instability. 2. The intrinsic anatomy of the radial side of the MP joint is not a mirror image of the ulnar aspect. Significant anatomic differences account for distinctive patterns of instability. Whereas disruption of the ulnar collateral ligament in conjunction with dorsal capsular tears is apt to result in combined radiovolar subluxation, disruption of the radial collateral ligament, coupled with the unopposed dynamic force of the adductor pollicis, characteristically is prone to a rapid pathologic sequence of profound joint instability, with progressive ulnar and volar subluxation and, ultimately, degenerative joint disease. 3. Optimal management of the complete collateral ligament lesion requires prompt diagnosis, most accurately confirmed with physical and radiographic stress testing, and precise surgical repair. Immobilization alone is insufficient treatment for these serious ligament disruptions, characterized by considerable displacement with wide separation of torn ends. 4. Although early direct repair affords the best opportunity for restoration of joint integrity with a highly favorable functional recovery, secondary repair and free tendon grafting, prior to joint deformity, provide consistently successful options for chronic instability.     

Lunotriquetral instability: diagnosis and treatment

Isolated injury of the lunotriquetral interosseous ligament complex and associated structures is less common and is poorly understood compared with the other proximal-row ligament injury, scapholunate dissociation. The spectrum of injuries ranges from isolated partial tears to frank dislocation, and from dynamic to static carpal instability. The diagnosis may be difficult to establish because of the many possible causes of ulnar-sided wrist pain and the often normal radiographic appearance. The mechanism of injury is variable and includes attrition by age, positive ulnar variance, and perilunate or reverse perilunate injury. Appropriate treatment requires assessment of the degree of instability and the chronicity of the injury. Options include corticosteroid injection, immobilization, ligament repair, ligament reconstruction with tendon grafts, limited intercarpal arthrodesis, and ulnar shortening.     

Radiocarpal articular contact characteristics with scaphoid instability

The relative importance of the three major periscaphoid ligament complexes in maintaining the normal radiocarpal articulation was assessed. Pressure-sensitive film recorded the changes in radioscaphoid and radiolunate articular contact that occurred with sequential ligament sectioning in 12 cadaver wrists. Alterations in the radiocarpal articular contact as a result of ligament disruption are evident in the absence of the recognizable static x-ray changes of carpal instability. The scapholunate interosseous ligament is essential in preventing scapholunate diastasis and dorsoradial subluxation of the proximal scaphoid. Rotatory subluxation of the scaphoid occurs when disruption of the scapholunate interosseous ligament is coupled with disruption of either the palmar intracapsular radiocarpal ligaments or the scaphotrapezial ligament complex. These data help explain the development of degenerative arthritis caused by carpal ligamentous instability.     

Isolated fracture-dislocation of the scaphoid’s proximal pole treated by scaphoid internal fixation and scapho-lunate ligament reconstruction

We present a case of irreducible palmar dislocation of the proximal fragment of a scaphoid fracture without carpal dislocation. We observed this lesion 2 days after the injury and we immediately operated the patient with a combined volar and dorsal access: using the Henry access we reduced the fracture and we inserted a cannulated screw to synthesize the scaphoid, using the dorsal access we repaired the complete rupture of the scapho-lunate ligament using a mini anchor. Stabilization among scaphoid, lunate and capitate was performed using Kirschner wires. X-ray showed fracture healing after 90 days. No clinical or radiographic evidence of carpal instability was revealed, on standard X-rays or on dynamic evaluations. No sign of avascular necrosis or degenerative arthritis was observed after 9 months.     

Trans-scaphoid perilunate fracture dislocations: results of screw fixation of the scaphoid and lunotriquetral repair with a dorsal approach

PURPOSE: To review the clinical and radiographic outcome of dorsal trans-scaphoid perilunate fracture-dislocations treated with screw fixation of the scaphoid and repair of the lunotriquetral ligament with bone anchors. METHODS: Twenty-five patients treated over an 11-year period for dorsal trans-scaphoid perilunate fracture-dislocations were reviewed retrospectively at a mean of 44.3 months. The mean age of the patients was 28.6 years, and 22 patients were men. Delay to surgery was 3.5 days. Five scaphoids had bone grafting from the distal radius. Six patients developed carpal tunnel syndrome requiring release. The functional outcome was determined by comparing the range of motion of the injured extremity with the uninjured extremity, grip strength, ability to return to pre-injury employment, and overall patient satisfaction. Radiographic evaluation comprised time to scaphoid union, any changes in the lunotriquetral interval, development of a volar intercalated segmental instability pattern, and any development of arthritis over time. RESULTS: Total range of motion achieved was 91% of the uninjured wrist and grip strength was 80%. Average extension was 54 degrees with an average flexion of 60 degrees . Ulnar deviation was 23 degrees with radial deviation averaging 18 degrees . The average supination was 76 degrees and the average pronation was 76 degrees . All scaphoids united primarily. The average time to union of the scaphoid was 16 weeks. For those scaphoids with bone grafting the union time was an average of 18.4 weeks. The average postreduction lunotriquetral gap was 1.8 +/- 0.4 mm. The average lunotriquetral gap at the last follow-up evaluation was 1.9 +/- 0.6 mm. None of the patients developed a volar intercalated segmental instability deformity. All but 2 patients returned to their pre-injury occupation. All patients, however, returned to some type of employment. Complications included 1 superficial pin track infection that resolved with removal of the pin and a short course of oral antibiotics. CONCLUSIONS: A dorsal approach to the wrist provides adequate exposure for reduction of carpal bones, internal fixation of the scaphoid, and lunotriquetral repair. Although perilunate fracture-dislocations are challenging problems to treat, all of the patients had acceptable pain relief and achieved sufficient range of motion and strength to return to gainful employment.     

Immunohistochemical analysis of wrist ligament innervation in relation to their structural composition

PURPOSE: To analyze ligament innervation and the structural composition of wrist ligaments to investigate the potential differences in sensory and biomechanical functions. METHODS: The ligaments analyzed were the dorsal radiocarpal, dorsal intercarpal, scaphotriquetral, dorsal scapholunate interosseous, scaphotrapeziotrapezoid, radioscaphoid, scaphocapitate, radioscaphocapitate, long radiolunate, short radiolunate, ulnolunate, palmar lunotriquetral interosseous, triquetrocapitate, and triquetrohamate ligaments. The ligaments were harvested from 5 cadaveric, fresh-frozen specimens. By using the immunohistochemical markers p75, Protein Gene Product 9.5, and S-100 protein, the mechanoreceptors and nerve fibers could be identified. RESULTS: The innervation pattern in the ligaments was found to vary distinctly, with a pronounced innervation in the dorsal wrist ligaments (dorsal radiocarpal, dorsal intercarpal, scaphotriquetral, dorsal scapholunate interosseous), an intermediate innervation in the volar triquetral ligaments (palmar lunotriquetral interosseous, triquetrocapitate, triquetrohamate), and only limited/occasional innervation in the remaining volar wrist ligaments. The innervation pattern also was reflected in the structural differences between the ligaments. When present, mechanoreceptors and nerve fibers were consistently found in the loose connective tissue in the outer region (epifascicular region) of the ligament. Hence, ligaments with abundant innervation had a large epifascicular region, as compared with the ligaments with limited innervation, which consisted mostly of densely packed collagen fibers. CONCLUSIONS: The results of our study suggest that wrist ligaments vary with regard to sensory and biomechanical functions. Rather, based on the differences found in structural composition and innervation, wrist ligaments are regarded as either mechanically important ligaments or sensory important ligaments. The mechanically important ligaments are ligaments with densely packed collagen bundles and limited innervation. They are located primarily in the radial, force-bearing column of the wrist. The sensory important ligaments, by contrast, are richly innervated although less dense in connective tissue composition and are related to the triquetrum. The triquetrum and its ligamentous attachments are regarded as key elements in the generation of the proprioceptive information necessary for adequate neuromuscular wrist stabilization.     

Arthroscopic and open management of dynamic scaphoid instability

This article focuses on the pathophysiology and treatment of dynamic scaphoid instability. Cadaver studies suggest that dynamic instability results from isolated injury to the scapholunate interosseous ligament without damage to the dorsal intercarpal and dorsal radial lunotriquetral ligaments. The diagnosis may be made by dynamic fluoroscopic examination, including stress and load views. The role of arthroscopy is twofold: (1) it enables the surgeon to distinguish between a complete, grossly unstable scapholunate interosseous space that requires open treatment and (2) it permits direct visualization of the reduction and percutaneous pinning of the articulation in an effort to stabilize the joint. Operative indications, open and arthroscopic techniques, and results are discussed.     

Lunotriquetral injuries in the athlete

The athlete with an LT injury typically presents with ulnar-sided wrist pain after a high-energy impaction of the wrist. Reagan's LT ballottement test and Kleinman's shear test help the examiner identify these injuries. A thorough radiographic examination includes standard PA and lateral radiographs. Magnetic resonance imaging or arthrography can be performed, but the sensitivity of these imaging studies varies. The palmar portion of the LT interosseous ligament, dorsal radiocarpal ligament, and dorsal intercarpal ligament play the most significant roles in LT stability. Lunotriquetral injuries without instability respond well to immobilization. Arthroscopy is valuable in staging and determining treatment but requires a thorough radiocarpal and midcarpal examination. Acute LT injuries with instability are treated with arthroscopic-assisted reduction and pinning. If desired, this procedure can be incorporated with an open ligament repair through a volar approach. Chronic LT tears without instability can also be treated arthroscopically. Treatment of the chronic LT tear with instability depends on the degree of collapse. Treatment in the athlete includes ligament reconstruction with capsulodesis or, rarely, intercarpal LT arthrodesis.     

桡骨远端骨折对腕关节稳定性的影响

目的研究各型桡骨远端骨折导致的腕关节不稳手术与非手术治疗的临床疗效及对腕关节稳定性的影响。方法1999年1月至2006年9月桡骨远端骨折患者200例,采用AO分型,标准腕关节正侧位片测量桡月角、舟月角、桡骨远端长度、关节面落差、舟月近远侧间距。手法复位石膏外固定患者和桡骨远端切开复位内固定治疗患者进行比较,采用改良Gartland和Werley评分标准评定腕关节功能恢复情况,并进行统计学分析。结果临床平均随访时间5年2个月,结果发现舟月分离、背屈不稳、掌屈不稳、背侧偏移和掌侧偏移5种腕关节不稳;优良率为78％。桡骨远端长度缩短≥2．5mm与〈2．5mm的桡骨远端骨折患者腕关节不稳发生率比较,Fisher确切概率P〈0．01;桡骨远端关节面的落差≥2mm与〈2mm的桡骨远端骨折患者腕关节不稳发生率比较,Fisher确切概率P〈0．01。结论桡骨远端骨折对桡腕关节面、桡骨远端长度、掌倾角的恢复与患者的疗效密切相关,腕关节的稳定性依赖于骨性结构和周围韧带的完整性,腕关节不稳将严重影响腕关节功能。对于严重关节内的骨折应手术治疗解剖复位。     

Carpal instability nondissociative

Carpal instability nondissociative (CIND) represents a spectrum of conditions characterized by kinematic dysfunction of the proximal carpal row, often associated with a clinical "clunk." CIND is manifested at the midcarpal and/or radiocarpal joints, and it is distinguished from carpal instability dissociative (CID) by the lack of disruption between bones within the same carpal row. There are four major subcategories of CIND: palmar, dorsal, combined, and adaptive. In palmar CIND, instability occurs across the entire proximal carpal row. When nonsurgical management fails, surgical options include arthroscopic thermal capsulorrhaphy, soft-tissue reconstruction, or limited radiocarpal or intercarpal fusions. In dorsal CIND, the capitate subluxates dorsally from its reduced resting position. Dorsal CIND usually responds to nonsurgical management; refractory cases respond to palmar ligament reefing and/or dorsal intercarpal capsulodesis. Combined CIND demonstrates signs of both palmar and dorsal CIND and can be treated with soft-tissue or bony procedures. In adaptive CIND, the volar carpal ligaments are slackened and are less capable of inducing the physiologic shift of the proximal carpal row from flexion into extension as the wrist ulnarly deviates. Treatment of choice is a corrective osteotomy to restore the normal volar tilt of the distal radius.     

Effects of radioulnar instability on the radiocarpal joint: a biomechanical study

Five fresh cadaver upper extremities were studied with use of a static positioning frame, pressure-sensitive film and a microcomputer-based videodigitizing system to assess the effect of increasing radioulnar instability on the load distribution within the proximal carpal joint. Three stages of radioulnar instability were studied: (1) an avulsion fracture at the base of the ulna styloid; (2) an avulsion fracture at the base of the ulna styloid plus disruption of the dorsal portion of the distal radioulnar joint capsule; and (3) an avulsion fracture at the base of the ulna styloid, disruption of the dorsal portion of the distal radioulnar joint capsule, and disruption of the radioulnar interosseous membrane. All stages of radioulnar instability demonstrated a decrease in the lunate contact area in positions with the forearm in supination. In stage 3 instability there was also less lunate contact area in positions with the forearm in neutral pronation/supination. In stage 3 instability the lunate high pressure area centroid was abnormally palmar in all positions and the scaphoid high pressure area centroid was abnormally palmar in positions with the forearm in pronation or supination.