Kinematics of the midcarpal and radiocarpal joint in flexion and extension: an in vitro study

PURPOSE: To apply carpal kinematic analysis using noninvasive medical imaging to investigate the midcarpal and radiocarpal contributions to wrist flexion and extension in a quasidynamic in vitro model. METHODS: Eight fresh-frozen cadaver wrists were scanned with computed tomography in neutral, full flexion, and full extension. Body-mass-based local coordinate systems were used to track motion of the capitate, lunate, and scaphoid with the radius as a fixed reference. Helical axis motion parameters and Euler angles were calculated for flexion and extension. RESULTS: Minimal out-of-plane carpal motion was noted with the exception of small amounts of ulnar deviation and supination in flexion. Overall wrist flexion was 68 degrees +/- 12 degrees and extension was 50 degrees +/- 12 degrees. In flexion, 75% of wrist motion occurred at the radioscaphoid joint, and 50% occurred at the radiolunate joint. In extension, 92% of wrist motion occurred at the radioscaphoid joint, and 52% occurred at the radiolunate joint. Midcarpal flexion/extension between the capitate and scaphoid was 0 degrees +/- 5 degrees in extension and 10 degrees +/- 13 degrees in flexion. Midcarpal flexion/extension between the capitate and lunate was larger, with 15 degrees +/- 11 degrees in extension and 22 degrees +/- 19 degrees in flexion. CONCLUSIONS: The capitate and scaphoid tend to move together. This results in greater flexion/extension for the scaphoid than the lunate at the radiocarpal joint. The lunate has greater midcarpal motion between it and the capitate than the scaphoid does with the capitate. The engagement between the scaphoid and capitate is particularly evident during wrist extension. Out-of-plane motion was primarily ulnar deviation at the radiocarpal joint during flexion. These results are clinically useful in understanding the consequences of isolated fusions in the treatment of wrist instability.     

In vivo radiocarpal kinematics and the dart thrower's motion

BACKGROUND: Wrist motion is dependent on the complex articulations of the scaphoid and lunate at the radiocarpal joint. However, much of what is known about the radiocarpal joint is limited to the anatomically defined motions of flexion, extension, radial deviation, and ulnar deviation. The purpose of the present study was to determine the three-dimensional in vivo kinematics of the scaphoid and lunate throughout the entire range of wrist motion, with special focus on the dart thrower's wrist motion, from radial extension to ulnar flexion. METHODS: The three-dimensional kinematics of the capitate, scaphoid, and lunate were calculated from serial computed tomography scans of both wrists of fourteen healthy male subjects (average age, 25.6 years; range, twenty-two to thirty-four years) and fourteen healthy female subjects (average age, 23.6 years; range, twenty-one to twenty-eight years), which yielded data on a total of 504 distinct wrist positions. RESULTS: The scaphoid and lunate primarily flexed or extended in all directions of wrist motion, and their rotation varied linearly with the direction of wrist motion (R2= 0.90 and 0.82, respectively). Scaphoid and lunate motion was significantly less along the path of the dart thrower's motion than in any other direction of wrist motion (p < 0.01 for both carpal bones). The scaphoid and lunate translated radially (2 to 4 mm) when extended, but they did not translate appreciably when flexed. CONCLUSIONS: The dart thrower's path defined the transition between flexion and extension rotation of the scaphoid and lunate, and it identified wrist positions at which scaphoid and lunate motion approached zero. These findings indicate that this path of wrist motion confers a unique degree of radiocarpal stability and suggests that this direction, rather than the anatomical directions of wrist flexion-extension and radioulnar deviation, is the primary functional direction of the radiocarpal joint.     

The effects of wrist distraction on carpal kinematics

Changes in carpal kinematics under wrist distraction were studied in fresh cadaveric specimens. A magnetic tracking device measured kinematic motions of the scaphoid, lunate, and third metacarpal relative to the fixed radius in 3 planes of passive motion (coronal, sagittal, and "dart throwers") under progressive distraction loads. The change in percent contribution of the radiocarpal and midcarpal joints was calculated. Radiocarpal motion during extension was decreased as increasing traction was applied, but it increased with flexion. Motion of the scaphoid relative to the lunate was smaller in the oblique plane, resulting in less radiocarpal motion than in the sagittal plane. In the coronal plane, traction had little effect on radial deviation, but ulnar angulation of the scaphoid was greater with ulnar deviation of the wrist. These results suggest that different degrees of tension exist in the palmar and dorsal ligaments with the wrist under traction and during different planes of wrist motion. If wrist motion is desired during fixed traction, such as used clinically with external fixation, the dart-throwers motion (wrist extension with radial deviation and wrist flexion with ulnar deviation) appears to have the least impact on radiocarpal motion. If greater radiocarpal motion is desired, however, such as during postoperative mobilization, flexion-extension and radioulnar deviation will create more radiocarpal motion than the dart-thrower's motion.     

Capitate-based kinematics of the midcarpal joint during wrist radioulnar deviation: an in vivo three-dimensional motion analysis

PURPOSE: The purpose of this study was to obtain qualitative and quantitative information regarding in vivo 3-dimensional (3D) kinematics of the midcarpal joint during wrist radioulnar deviation (RUD). METHODS: We studied the in vivo kinematics of the midcarpal joint during wrist RUD in the right wrists of 10 volunteers by using a technology without radioactive exposure. The magnetic resonance images were acquired during RUD. The capitate was registered with the scaphoid, the lunate, and the triquetrum by using a volume registration technique. Animations of the relative motions of the midcarpal joint were created and accurate estimates of the relative orientations of the bones and axes of rotation (AORs) of each motion were obtained. RESULTS: The scaphoid, lunate, and triquetrum motions relative to the capitate during RUD were found to be similar, describing a rotational motion around the axis obliquely penetrating the head of the capitate in almost a radial extension/ulnoflexion plane of motion of the wrist. The AORs of the scaphoid, the lunate, and the triquetrum were located closely in space. In the axial plane the AORs of the scaphoid, lunate, and triquetrum formed a radially and palmarly opening angle of 43 degrees +/- 7 degrees, 41 degrees +/- 11 degrees, and 42 degrees +/- 14 degrees with the wrist flexion/extension axis, respectively. CONCLUSIONS: This study reports the in vivo 3D measurements of midcarpal motion relative to the capitate. Isolated midcarpal motion during RUD could be approximated to be a rotation in a plane of a radiodorsal/ulnopalmar rotation of the wrist, which may coincide with a motion plane of one of the most essential human wrist motions, known as the dart-throwing motion.     

部分腕骨融合术或切除术对腕关节运动影响的实验研究

目的 研究临床常用的部分腕骨融合术或切除术对腕关节运动的影响程度。方法 将１２侧新鲜上肢处理后,固定于特制的测试架上,在腕背部打入２根或多根克氏针,作舟头骨、舟大小多角骨、舟月骨、月三解骨、桡月骨、ｆｏｕｒ ｃｏｒｎｅｒ、头月骨融合术、舟骨切除＋ｆｏｕｒ ｃｏｒｎｅｒ、舟骨切除＋头月融合术。观测腕关节正常运动活动范围,及作上述不同部分腕骨融合术后腕关节屈曲、伸腕、尺偏、桡偏度数。结果 桡舟月骨融合     

Kienbock's disease: diagnosis and treatment

Kienbock's disease, or osteonecrosis of the lunate, can lead to chronic, debilitating wrist pain. Etiologic factors include vascular and skeletal variations combined with trauma or repetitive loading. In stage I Kienbock's disease, plain radiographs appear normal, and bone scintigraphy or magnetic resonance imaging is required for diagnosis. Initial treatment is nonoperative. In stage II, sclerosis of the lunate, compression fracture, and/or early collapse of the radial border of the lunate may appear. In stage IIIA, there is more severe lunate collapse. Because the remainder of the carpus is still uninvolved, treatment in stages II and IIIA involves attempts at revascularization of the lunate-either directly (with vascularized bone grafting) or indirectly (by unloading the lunate). Radial shortening in wrists with negative ulnar variance and capitate shortening or radial-wedge osteotomy in wrists with neutral or positive ulnar variance can be performed alone or with vascularized bone grafting. In stage IIIB, palmar rotation of the scaphoid and proximal migration of the capitate occur, and treatment addresses the carpal collapse. Surgical options include scaphotrapeziotrapezoid or scaphocapitate arthrodesis to correct scaphoid hyperflexion. In stage IV, degenerative changes are present at the midcarpal joint, the radiocarpal joint, or both. Treatment options include proximal-row carpectomy and wrist arthrodesis.     

Partial arthrodesis of the wrist: An investigation in cadavers

Partial arthrodesis of the wrist was performed on six cadavers in order to study the residual excursion of the wrist. Arthrodesis between the radius and scaphoid left 40 per cent extension/flexion and 61 per cent radial/ulnar deviation. Arthrodesis between the radius, scaphoid and lunate left 36 per cent extension/flexion and 59 per cent radial/ulnar deviation. Arthrodesis between the capitate, scaphoid and lunate left 59 per cent extension/flexion and 91 per cent radial/ulnar deviation.     

2007 IFSSH committee report of wrist biomechanics committee: biomechanics of the so-called dart-throwing motion of the wrist

The dart-throwing motion (DTM) plane can be defined as a plane in which wrist functional oblique motion occurs, specifically from radial extension to ulnar flexion. Most activities of daily living are performed using a DTM. The DTM utilizes the midcarpal joint to a great extent. Scaphotrapezio-trapezoidal anatomy and kinematics may be important factors that cause a DTM to be a more stable and controlled motion. During a DTM, there is less scaphoid and lunate motion than during pure flexion-extension or radioulnar deviation. Clinically, a DTM at the plane approximately 30 degrees to 45 degrees from the sagittal plane allows continued functional wrist motion while minimizing radiocarpal motion when needed for rehabilitation.     

In vivo three-dimensional wrist motion analysis using magnetic resonance imaging and volume-based registration.

This study represents a new attempt to non-invasively analyze three-dimensional motions of the wrist in vivo. A volume-based registration method using magnetic resonance imaging (MRI) was developed to avoid radiation exposure. The primary aim was to evaluate the accuracy of volume-based registration and compare it with surface-based registration. The secondary aim was to evaluate contributions of the scaphoid and lunate to global wrist motion during flexion-extension motion (FEM), radio-ulnar deviation (RUD) and radial-extension/ulnoflexion, "dart-throwing" motion (DTM) in the right wrists of 12 healthy volunteers. Volume-based registration displayed a mean rotation error of 1.29 degrees +/-1.03 degrees and a mean translation error of 0.21+/-0.25 mm and was significantly more accurate than surface-based registration in rotation. Different patterns of contribution of the scaphoid and lunate were identified for FEM, RUD, and DTM. The scaphoid contributes predominantly in the radiocarpal joint during FEM, in the midcarpal joint during RUD and almost equally between these joints during DTM. The lunate contributes almost equally in both joints during FEM and predominantly in the midcarpal joint during RUD and DTM.     

The double-cup carpus: a demonstration of the variable geometry of the carpus

OBJECTIVES: The variable frontal geometry of the carpus has been known for many years, however there is no unanimity as to whether to describe the dynamic model of the carpus as comprising row or columnar functional units. The place of the scaphoid is also discussed. This study attempts to understand the organization and the composition of the functional units of the carpus. METHODS: We took radiographs of 40 normal right wrists in radial and ulnar deviation and measured the displacement in the coronal plane of each carpal bone except the pisiform. We measured the angular movements of each carpal bone compared to a vertical axis passing through the geometric centre of the carpus. This axis is parallel to the radial axis which is defined as the line joining the midpoints of the radius at 2 and 5 cm proximal to the radial articular surface. We studied the movement of each row and each column. RESULTS: Recorded angular movements were the followings: scaphoid 26 degrees, lunate 28 degrees, triquetrum 29 degrees, trapezium 44 degrees, trapezoid 50 degrees, capitate 50 degrees, hamate 56 degrees. Average angular movement within the first row is 27 degrees, within the second row is 50 degrees. Average angular movement within the radial column is 38 degrees, middle column is 39 degrees, ulnar column is 42 degrees. CONCLUSIONS: The amplitude of movement are similar for the bones of each row, and different for the bones of each column. The bones of each row tend to move together and can alone account for all movements of the wrist. The movements measured between each column are torsional intrarow movements, allowing congruence between the two rows and the glenoid surface of the radius. The scaphoid movements are superposable with those of lunate and triquetrum. Scaphoid kinematics joins the first row. Radio-ulnar deviation of the wrist is shared equally between the radiocarpal and midcarpal joints. This sharing of wrist movement between the two rows constitutes for us a double cup carpal model.     

Scaphoid and lunate motion during a wrist dart throw motion

PURPOSE: The primary purpose of this study was to measure the in vitro scaphoid and lunate motion during 9 different variations of a wrist dart throw motion. Another goal was to determine the specific dart throw motion that minimized scaphoid and lunate motion. METHODS: Scaphoid and lunate motion were recorded in 7 cadaver forearms during various combinations of wrist dart throw motions caused by a wrist joint motion simulator. RESULTS: During wrist flexion and extension the scaphoid and lunate motions follow the wrist motion. During wrist radial and ulnar deviation the scaphoid and lunate correspondingly flex and extend. During intermediate motions the scaphoid and lunate move as little as 26% of the total third metacarpal motion and do not necessarily follow a planar motion. CONCLUSIONS: These findings suggest that there may be a dart throw motion during which there may be minimal scaphoid and lunate motion. If a subject's wrist motion could be clinically restricted to this dart throw motion, early hand mobility might be possible after surgery on the scaphoid and lunate.     

The ligaments of the wrist.

The ligaments of the wrist were studied by dissecting ten fixed and seven fresh frozen wrists. In three other specimens multiple cross-sections were prepared. These studies show that the wrist ligaments can be classified into two groups: extrinsic and intrinsic. In the extrinsic group, the deep volar radiocarpal ligaments are three strong and very important structures connecting the radius to the capitate, the radius to the lunate, and, in a deeper layer, the radius to both the scaphoid and the lunate. A ligamentous deficiency was noted frequently between the capitate and the lunate. There also are very strong volar connections between the radius and the medial or ulnar carpus. These studies suggest that certain patients with a generalized ligamentous laxity and weakness will develop a pathological disruption of the volar ligaments with trauma. These torn volar ligaments should be repaired or reconstructed, for repair of only the dorsal ligaments seldom will provide good stability to such wrists.     

In vivo scaphoid, lunate, and capitate kinematics in flexion and in extension

Carpal kinematics have been previously limited to in vitro models with cadaveric specimens. Using a newly developed markerless bone registration algorithm, we noninvasively studied the in vivo kinematics of the capitate, scaphoid, and lunate during wrist extension and flexion in both wrists of 5 men and 5 women. Computed tomography volume images were acquired in neutral and in 2 positions in both extension and flexion. The 3-dimensional kinematics of the capitate, scaphoid, and lunate relative to the radius were the determined. Scaphoid and lunate rotations differed for flexion and extension but were found to vary linearly with capitate rotation. In flexion the scaphoid contributed 73% of capitate motion and the lunate contributed 46%. In extension the scaphoid contributed 99% of capitate motion and the lunate contributed 68%. Contributions of the scaphoid and lunate to wrist extension were 15% greater than values reported in previous in vitro studies, while scaphoid and lunate contributions to wrist flexion were more similar to previous studies. The findings support a relative "engagement" of the scaphoid, capitate, and lunate during wrist extension. The only difference between male and female kinematics was a more distal location of the rotation axes; we believe this was due to a difference in carpal bone size, not gender. This study reports the 3-dimensional in vivo measurement of carpal motion using a noninvasive technology. This technique may prove useful in the study of more complex motions of the hand and wrist and of the abnormal kinematics that occur following ligamentous injury.     

The effect of sectioning the dorsal radiocarpal ligament and insertion of a pressure sensor into the radiocarpal joint on scaphoid and lunate kinematics.

The role of the dorsal radiocarpal wrist ligament has been the subject of several investigations. Several biomechanical studies have used sensors inserted dorsally into the wrist joint to evaluate its pressure distribution. The purpose of this study was to evaluate whether a dorsal capsulotomy that sections the dorsal radiocarpal ligament or insertion of a flexible pressure sensor alters scaphoid or lunate kinematics. Eight cadaver upper extremities were instrumented with motion sensors and placed in a wrist joint simulator. Each arm was moved through continual cycles of wrist flexion/extension and radial/ulnar deviation. Motion data were obtained in the intact state, after a capsulotomy, and after insertion of the sensor. We found that either a dorsal capsulotomy sectioning the dorsal radiocarpal ligament or insertion of the pressure sensor alters scaphoid and lunate kinematics during dynamic wrist motion. This study supports the clinical belief that this dorsal wrist ligament should be spared during surgical approaches to the carpus.     

Mediokarpale Teilarthrodese des Handgelenks mittels Spiderplatte

Objective

Pain relief while preserving wrist motion in advanced carpal collapse.

Indications

Advanced carpal collapse stage II/III due to scaphoid non-union, scapholunate ligament tear, idiopathic radiocarpal osteoarthritis, aseptic osteonecrosis of the scaphoid (Preisser??s disease). A relative indication is chronic midcarpal instability.

Contraindications

Osteoarthrisis of the lunate. Radiocarpal instability with ulnar translation of the wrist.

Surgical technique

Dorsal curved incision between the 3rd and 4th dorsal extensor compartment. Partial wrist denervation (posterior interosseous nerve). Raising of a radial pedicled capsule flap. Complete extirpation of the scaphoid without fragmentation. Cartilage removal of all the joint facets for arthrodesis. Reduction of the lunate and temporary fixation with K?wires between the triquetrum and capitate and the triquetrum and lunate. Milling the plate hole exactly in central position of the four carpal bones. The plate should not protrude from the bone to avoid impingement with the dorsal limb of the radius. Transferring of spongiosa harvested from the removed scaphoid into the arthrodesis gap. Fixation of the 8-hole plate with 2?screws in each of the four carpal bones. Fluoroscopy of the screw fitting. Control of the correct wrist articulation (motion test). Lavage of the wrist. Suture of the capsule flap. Redon drain, wound closure, dorsal splinting.

Postoperative management

Dorsal splint for 3?weeks; finger mobilization up to complete fist closure starting on postoperative day?1. From week 4?C6, active wrist motion, from week 7?C10 with increasing load. Return to work after 11?C12 weeks. CT scan in cases of delayed union, abnormal function, or persistence of pain.

Results

Between 2002 and 2008, 36?four-corner fusions (32?male, 4?female) with the spider plate were performed in 24 right and 12 left wrists. The mean age of the patients at surgery was 48?years (range 32?C71?years). Follow-up examinations were performed in 11 patients. The Krimmer and Rudolf scores were determined: 1?excellent, 7?good, 2?satisfactory, and 1?poor result were found. The mean grip strength was 51% relative to the opposite wrist. The mean range of motion (ROM) for wrist extension/flexion was 56% of the opposite side. Wrist extension/flexion averaged 24/0/32° and ulnar/radial deviation was on average 20/0/19°. Pain during activity was on average 2.2 based on the visual analogue scale (0?C10). One delayed bony union due to a screw breakage, which required total wrist fusion, was observed.     

Biomechanical evaluation of the ligamentous stabilizers of the scaphoid and lunate: part III

PURPOSE: This study continued our previous investigations of the ligaments stabilizing the scaphoid and lunate in which we examined the scapholunate interosseous ligament, the radioscaphocapitate, and the scaphotrapezial ligament. In this current study, we examined the effects of sectioning the dorsal radiocarpal ligament, dorsal intercarpal ligament, scapholunate interosseous ligament, radioscaphocapitate, and scaphotrapezial ligaments. In the current study, the scapholunate interosseous ligament, radioscaphocapitate, and scaphotrapezial ligaments were sectioned in a different order than performed previously. METHODS: Three sets of 8 cadaver wrists were tested in a wrist joint motion simulator. In each set of wrists, only 3 of the 5 ligaments were cut in specific sequences. Each wrist was moved in continuous cycles of flexion-extension and radial-ulnar deviation. Kinematic data for the scaphoid and lunate were recorded for each wrist in the intact state, after the 3 ligaments were sectioned in various sequences and after the wrist was moved through 1,000 cycles of motion. RESULTS: Dividing the dorsal intercarpal or scaphotrapezial ligaments did not alter the motion of the scaphoid or lunate. Dividing the dorsal radiocarpal ligament alone caused a slight statistical increase in lunate radial deviation. Dividing the scapholunate interosseous ligament after first dividing the dorsal intercarpal, dorsal radiocarpal, or scaphotrapezial ligaments caused large increases in scaphoid flexion and lunate extension. CONCLUSIONS: Based on these findings, we concluded that the scapholunate interosseous ligament is the primary stabilizer and that the other ligaments are secondary stabilizers of the scapholunate articulation. Dividing the dorsal radiocarpal, dorsal intercarpal, or scaphotrapezial ligaments after cutting the scapholunate interosseous ligament produces further changes in scapholunate instability or results in changes in the kinematics for a larger portion of the wrist motion cycle.     

Combined radiocarpal arthrodesis and midcarpal (lunocapitate) arthroplasty for treatment of rheumatoid arthritis of the wrist

Arthroplasties for the wrist with rheumatoid arthritis are usually revised for the articulation between radius and carpus. The midcarpal joint is disregarded although it remains structurally better preserved and is therefore better suited for the preservation of stable motion. When the midcarpal surfaces are satisfactory, a radio-scapho-lunate fusion, accompanied by a midcarpal synovectomy, is an excellent procedure. When the midcarpal surfaces, particularly the head of the capitate, are also destroyed, the tendency has been to either perform a pan-arthrodesis, or to insert a wrist endo-prosthesis. For these severely unstable and destroyed wrists, a stabilization of the radiocarpal joint by arthrodesis, combined with preservation of motion at the midcarpal level by resection of the damaged head of the capitate and its replacement with a small implant has been done. This procedure has allowed all patients to retain a functional range of motion and to experience satisfactory relief of pain.     

The palmar radiocarpal ligaments: A study of adult and fetal human wrist joints

The palmar radiocarpal ligaments were studied with use of fifty-four dissected adult cadaver wrists and serial sections on twenty-three wrists from fetuses ranging in size from 23 to 230 millimeters crown-rump length. Three palmar radiocarpal ligaments were clearly identified: the radioscaphocapitate, long radiolunate, and short radiolunate ligaments. The radioscaphocapitate ligament originates from the radial styloid process and inserts into the radial aspect of the waist of the scaphoid, hemicircumferentially around the distal pole of the scaphoid and interdigitates with fibers from the palmar aspect of the triangular fibrocartilage complex just palmar to the head of the capitate, with only a minor insertion distally into the body of the capitate. The long radiolunate ligament originates just ulnar to the radioscaphocapitate ligament, being separated from it throughout its course by the interligamentous sulcus. The long radiolunate supports, but is separate from, the palmar aspect of the scapholunate interosseous ligament, and inserts into the radial half of the palmar surface of the lunate. The short radiolunate ligament, previously not described, originates just palmar to the lunate facet of the distal radius articular surface and inserts as a flat sheet of fibers into the proximal margin of the palmar surface of the lunate. Each ligament is intracapsular, enveloped within a continuous superficial fibrous stratum and deep synovial stratum.     

Scaphoid nonunion and distal fragment resection: analysis with three-dimensional rigid body spring model

Background  Distal fragment resection is one of the salvage procedures for scaphoid nonunion with osteoarthritis. Despite being reported as a simple procedure with favorable midterm outcomes, further arthritic changes remain a concern in the long term. Scaphoid waist fracture is classified into volar or dorsal types according to the displacement pattern, but the indications for distal fragment resection have never been discussed for these fracture types. Method  We reconstructed a normal wrist model from computed tomography images and performed theoretical analysis utilizing a three-dimensional rigid body spring model. Two types of scaphoid fracture nonunion followed by distal fragment resection were simulated. Results  With volar-type nonunion, the force transmission ratio of the radiolunate joint increased, and the pressure concentration was observed in the dorsal part of the scaphoid fossa and volar part of the lunate fossa of the radius; no deterioration was seen in the midcarpal joint. In the distal fragment resection simulation for volar-type nonunion, pressure concentrations of the radiocarpal joint resolved. With dorsal-type nonunion, force transmission ratio in the radiocarpal joint resembled that of the normal joint model. Pressure concentrations were observed in the dorsoulnar part of the scaphoid fossa and radial styloid. The pressure concentration in the dorsoulnar part of the scaphoid fossa disappeared in the resection model, whereas the concentration in the radial styloid remained. In the midcarpal joint, pressure was concentrated around the capitate head in the nonunion model and became aggravated in the resection model. Conclusions  With volar-type scaphoid nonunion, distal fragment resection seems to represent a reasonable treatment option. With dorsal-type nonunion, however, pressure concentration around the capitate head was aggravated with the simulated distal fragment resection, indicating a potential risk of worsening any preexisting lunocapitate arthritis.