Proximal Wrist Joints Research Articles

A biomechanical model of the wrist joint for patient-specific model guided surgical therapy: Part 2.

An enhanced musculoskeletal biomechanical model of the wrist joint is presented in this article. The computational model is based on the multi-body simulation software AnyBody. Multi body dynamic musculoskeletal models capable of predicting muscle forces and joint contact pressures simultaneously would be valuable for studying clinical issues related to wrist joint degeneration and restoration. In this study, the simulation model of the wrist joint was used for investigating deeper the biomechanical function of the wrist joint. In representative physiological scenarios, the joint behavior and muscle forces were computed. Furthermore, the load transmission of the proximal wrist joint was investigated. The model was able to calculate the parameters of interest that are not easily obtainable experimentally, such as muscle forces and proximal wrist joint forces. In the case of muscle force investigation, the computational model was able to accurately predict the computational outcome for flexion and extension motion. In the case of force distribution of the proximal wrist joint, the model was able to predict accurately the computational outcome for an axial load of 140 N. The presented model and approach of using a multi-body simulation model are anticipated to have value as a predictive clinical tool including effect of injuries or anatomical variations and initial outcome of surgical procedures for patient-specific planning and custom implant design. Therefore, patient-specific multi-body simulation models are potentially valuable tools for surgeons in pre- and intraoperative planning of implant placement and orientation.

Scaphoid anatomy and mechanics: Update and review

This review has been an attempt to collate previous research on scaphoid anatomy, load mechanics and kinematics into one article so that the reader can assimilate the information in a convenient way. The scaphoid is a unique carpal bone in shape and function. It has a three-dimensionally oblique orientation and performs a unique function as a mechanical link between the distal and proximal carpal rows on the radial aspect. The load mechanics of the scaphoid play an important role in wrist function and kinematics. Studies of the normal biomechanics of the proximal wrist joint have determined that the scaphoid and lunate bones have separate, distinct areas of contact on the distal radius surface. Kinematics of the scaphoid can be viewed either from proximal or distal. From a proximal view, during radial/ulnar deviation of the wrist, the scaphoid exhibits both a flexion/extension and radial/ulnar deviation motion. Distally, kinematic studies revealed that the scaphoid-trapezoid motion during wrist extension is the same as in wrist radial deviation and the scaphoid-trapezoid motion in wrist flexion is the same as in wrist ulnar deviation. Knowledge of the anatomy of the dorsal carpal ligaments has also provided a wealth of information on their role in carpal motion. The lateral V construct of the DRC (Dorsal Radiocarpal), DIC (Dorsal Intercarpal), and dorsal component of the SLIO (Scapho-lunate interosseous) ligament delivers indirect dorsal stability, yet allows relative free motion of the scaphoid. Injuries that involve the scaphoid can be ligamentous or can involve fracture of the scaphoid with or without ligamentous injury. Because of its complex anatomy, treating scaphoid fractures and nonunions can be challenging and difficult to detect true displacement patterns from plain X-ray films due to the overlapping of the other carpal bones. Degenerative arthritis of the STT (scapho-trapezium-trapezoid) joint is the second most common site of degenerative changes in the wrist. Plain radiographs can be used to measure TT (trapezium-trapezoid) inclination, which has been shown to be correlated with degenerative changes in the STT joint. Research in our lab has demonstrated that wrists with a higher TT inclination had a higher incidence of degenerative changes. This new perspective taking into account anatomy, mechanics and kinematics begins to offer a more global view of how form and function are related and what part the scaphoid plays in carpal function and stability.

Anatomy of the squirrel wrist: bones, ligaments, and muscles.

Anatomical differences among squirrels are usually most evident in the comparison of flying squirrels and nongliding squirrels. This is true of wrist anatomy, probably reflecting the specializations of flying squirrels for the extension of the wing tip and control of it during gliding. In the proximal row of carpals of most squirrels, the pisiform articulates only with the triquetrum, but in flying squirrels there is also a prominent articulation between the pisiform and the scapholunate, providing a more stable base for the styliform cartilage, which supports the wing tip. In the proximal wrist joint, between these carpals and the radius and ulna, differences in curvature of articular surfaces and in the location of ligaments also correlate with differences in degree and kind of movement occurring at this joint, principally reflecting the extreme dorsal flexion and radial deviation of the wrist in flying squirrels when gliding. The distal wrist joint, between the proximal and distal rows of carpals, also shows most variation among flying squirrels, principally in the articulations of the centrale with the other carpal bones, probably causing the distal row of carpal bones to function more like a single unit in some animals. There is little variation in wrist musculature, suggesting only minor evolutionary modification since the tribal radiation of squirrels, probably in the early Oligocene. Variation in the carpal bones, particularly the articulation of the pisiform with the triquetrum and the scapholunate, suggests a different suprageneric grouping of flying squirrels than previously proposed by McKenna (1962) and Mein (1970). J. Morphol. 246:85-102, 2000. Published 2000 Wiley-Liss, Inc.

Functional morphology of the lemuriform wrist joints and the relationship between wrist morphology and positional behavior in arboreal primates

A comparative study of carpal joint structure and function in six Malagasy lemuriforms was undertaken to test predicted morphoclines in carpal joint morphology between pronograde and orthograde arboreal primates. Patterns of movement at the wrist during locomotion were observed and described for the lemuriform species Lemur fulvus and Propithecus verreauxi. Lemur fulvus, which assumes a pronograde posture during locomotion, extends and pronates the wrist during the support phase of quadrupedal walking and running stride cycles. Furthermore, the forearm of this species exhibits some transverse movement across the proximal wrist joint during the support phase. In contrast, the indriid Propithecus maintains the hand and wrist in a flexed and partially supinated position during vertical clinging and suspensory postures. Habitual quadrupedal and vertical postures in Malagasy primates are in turn related to very different patterns of carpal joint morphology and articular mechanics. Those lemurs which are predominantly pronograde share a series of structural features related to stabilizing the antebrachiocarpal joint during extension and mediolateral deviation and the midcarpal joint during pronation: an intraarticular labrum is present on the inner portion of the radiocarpal ligament, the radiocarpal articular surface is quite flat dorsoventrally, the capitate-trapezoid embrasure is expanded dorsally, and development of the radial and ulnar styloids is more pronounced. The wrists of Propithecus, Avahi, and Lepi-lemur (vertical clingers) differ from those of quadrupedal lemuriforms in possessing a suite of morphological features related to stabilizing the wrist during antebrachiocarpal flexion and midcarpal supination: the radiocarpal articular surface is deeply curved and tilted anteriorly, the dorsal radiocarpal ligament is very broad, thick, and fibrous, the hamate's triquetral facet is directed proximodistally, and the capitate-trapezoid embrasure is dorsally constricted and expanded palmarly. These observed contrasts in carpal form and function are used to define further the morphological features related to orthograde posture in several lineages of arboreal primates.

MIDCARPAL ARTHROSCOPY: ANATOMY AND PORTALS

Arthroscopy of the midcarpal joint of the wrist is a relatively new procedure made possible by the advances and miniaturization of arthroscopic instrumentation. Only recently has even the basic variability in the normal anatomy of the midcarpal joint been delineated. Midcarpal arthroscopy is becoming a routine part of a complete diagnostic wrist arthroscopy and is offering good views of midcarpal anatomy and new opportunities for arthroscopic treatment of midcarpal and proximal wrist joint traumatic and degenerative pathology.

Wrist anatomy: Incidence, distribution, and correlation of anatomic variations, tears, and arthrosis

We dissected 393 wrists to evaluate the incidence and distribution of anatomic features, arthrosis, chondromalacia, and soft tissue lesions. The data were then analyzed for any statistically significant associations among the different variables. The most common (73%) lunate morphology had a separate medial facet on its distal surface for the hamate. The capitate had a separate facet for the fourth metacarpal in 86% of the wrists. Fourth metacarpals with a dorsal radial facet, either separate from or connected to the rest of the fourth metacarpal base, were the most common types of fourth metacarpal. Cartilage erosion with exposed subchondral bone was identified in 58% of the wrists. It was most commonly at the proximal pole of the hamate (28%). Tears of the ligaments and/or the triangular fibrocartilage complex were identified in 56% of the wrists. The triangular fibrocartilage complex was found torn in 36% of the wrists. The lunotriquetral interosseous ligament was torn in 36% of the wrists, and the scapholunate interosseous ligament was torn in 28% of the wrists. There was a communication between the proximal wrist joint and the pisotriquetral joint in 88% of the 76 wrists, which were further dissected to assess this issue. Statistical analysis of the data found a significant correlation between the presence of cartilage erosion at the proximal pole of the hamate and the presence of a lunate facet. There was also a significant correlation between the presence of a tear in the scapholunate interosseous ligament and the presence of cartilage erosion in the scaphoid-trapezium-trapezoid joint. Analysis of the paired wrists from 169 cadavers revealed that the same soft tissue tear or combination of tears was present bilaterally in 39% of the pairs. Cartilage erosion was present bilaterally in the same location or locations in 27% of the pairs.

Midcarpal arthroscopy: Anatomy and technique

Wrist arthroscopy has had a dramatic impact in both evaluation and treatment of a variety of wrist problems. Wrist arthroscopy has typically meant arthroscopy of the proximal wrist joint; however, midcarpal joint arthroscopy is becoming a routine part of a complete arthroscopic examination of the wrist. Specific indications, pertinent anatomy, and a clear technique for performing a midcarpal arthroscopy is not well documented in the literature. This article attempts to offer some insight on these issues.

Anatomy of the hominoid wrist joint: Its evolutionary and functional implications

Observations on the behavior of living hominoids show generic differences in the use and posture of the wrist joint. Both orang-utans and hylobatids usually use the wrist in suspensory behaviors. However, orang-utans emphasize markedly adducted and flexed wrist postures, while hylobatids emphasize violent forearm and wrist rotation. African apes, especially the gorilla, use the wrist more frequently than other hominoids for terrestrial quadrupedal weight-bearing. Humans use the wrist less frequently for supportive purposes than do other hominoids. These behavioral differences correspond to structural specializations in the proximal carpal joint of each of the hominoid genera. Although each of the hominoid genera has apparently modified its proximal carpal joint best to serve its characteristic behaviors, all hominoids share a unique proximal carpal joint that permits approximately 160ℴ of forearm rotation. The hylobatid proximal carpal joint is specialized in exhibiting a marked development of those structures limiting forearm rotation, but it is in most respects the least derived— that is, closest to the nonhominoid anthropoids. Chimpanzees show a proximal carpal joint that is more generalized than those of the other great apes but more derived than that of hylobatids. The human and gorilla proximal wrist joints, on the other hand, show marked modifications for weight-bearing in terrestrial behaviors. Orang-utans have the most derived proximal carpal joint, which in many respects parallels that of the slow-climbing nonhominoid primates. The comparative anatomy and structural specializations of the wrist joint support (a) an early divergence of hylobatids from the common hominoid stock, (b) a common ancestry for gorillas and humans separate from the other hominoids, and (c) a long independent evolutionary period for orang-utans since their divergence from the common hominoid stock, or one that was marked by strong selection pressures for wrist specializations. Unfortunately, the generalized condition of the chimpanzee’s wrist joint and the very derived condition of the orang-utan wrist provide uncertain evidence as to which of the two was first to diverge from the common hominoid stock. Identification of hominoid wrist specializations as reflecting real phylogenetic relationships or parallelisms depends on how well the phytogeny inferred from wrist morphology accords with those arrived at from the study of other systems.

Anatomie des Handgelenkes und der Handwurzel

A systematic anatomical representation of the carpal area is not an adequate means to show its way of function. This paper describes the functional correlations between the distal radio-ulnar joint and the wrist joint. The proximal wrist joint is composed of two mechanically equivalent compartments. Within the ulnocarpal joint, the disk fulfills a most important function as a surface adapting and pressure transmitting element. Its perforation is a pre-arthrotic deformity. The column conception of the carpus is supported by cinematic studies as well as by analyses of the subchondral bone density and the spongy structure of the ossa carpi. This conception presumes a radial scaphoid column, a central lunate column, and an ulnar triquetrum column.