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S F Viegas

Publications and source records attributed to S F Viegas.

At least 37 records · Page 2Linked to original sources
PubMed1998

Anatomic study of the pisotriquetral joint: ligament anatomy and cartilagenous change.

Eighty embalmed cadaver wrists (40 right and 40 left, 55 male and 25 female, aged 36 to 93 years [average age, 72.5 years]) were dissected to assess the anatomy of the pisotriquetral joint and the location of degenerative changes. The patterns of degenerative changes were classified into five types: type 1, central (8.8%); type 2, peripheral (38.8%); type 3, fan-shaped (13.8%); type 4, mixed (combination of > or =1 of types 1, 2, and/or 3; 10.0%); and type 5, total (12.5%). There was no cartilagenous change in 16.2% of the pisoform and 13.7% of the triquetrum. Degenerative changes (exposed subchondral bone and chondromalacia) on the articular surface of the pisiform were present in 83.3% of the wrists and on the triquetrum in 86.3% of the wrists. Degenerative changes were most commonly of the type 2 pattern (peripheral), with change located most commonly in the distal, distal-radial, and radial aspects of the pisiform and triquetrum. The ligamentous anatomy was categorized into 3 different types: type A, pisohamate and pisometacarpal ligaments inserted on the palmar distal aspect of the pisiform (52.5%); type B, pisohamate ligament inserted on the radial side of the pisiform and pisometacarpal ligament inserted on the palmar side of the pisiform (41.3%); and type C, type B anatomy with an additional ligamentous slip between the pisometacarpal ligament and the distal aspect of the hook of the hamate (6.2%).

Adult↗
PubMed1998

Ulnar-sided wrist pain and instability.

A variety of lesions have been associated with ulnar-sided wrist pain and/or VISI instability. A staging system for ulnar-sided perilunate instability describes progressive disruptions associated with lunotriquetral dissociation that can lead to VISI instability and emphasizes the importance of the dorsal radiocarpal ligament in preventing VISI instability. Previous studies have emphasized association between type II carpal morphology and arthrosis at the proximal pole of the hamate, which was identified as the most common location of arthrosis in the wrist. The pisotriquetral joint is another common site of degenerative changes. A better understanding of the normal anatomy and kinematics of the ulnar side of the wrist will better enable physicians to identify and treat problems in the ulnar aspect of the wrist.

Arthralgia↗
PubMed1998

Causes of upper extremity compartment syndrome.

Multiple causes, including various types of trauma, prolonged compression, muscle avulsions, burn, snake bites, high-pressure injection injuries, exercise, infection, bleeding, and intravenous drug infiltration, have been reported to lead to the development of a compartment syndrome in the upper extremity. Awareness of the different causes and risks of compartment syndrome should facilitate early diagnosis and prompt treatment to help avoid the development of serious sequelae such as Volkmann's ischemic contracture. A review of the various reports of upper extremity compartment syndromes and classification systems is presented to assist in the understanding of this condition's development.

Arm↗
PubMed1997

Chronic wrist pain.

Nonarticular chronic wrist pain continues to be a challenging subject in which interest and knowledge are increasing. Although many more excellent articles could have been included in this review, an attempt is made to discuss papers that have impact on the recognition, diagnosis, and treatment of various wrist problems. Developments in diagnostic algorithms and refinements in the use of imaging and arthroscopic tools are reviewed. Arthroscopy provides exciting direct visual information and therapeutic opportunities for triangular fibrocartilage complex disruptions and lunatotriquetral ligament pathology. A new carpal instability analysis system is proposed to allow better comparison of results reported in the literature. Comprehensive evaluation and treatment of the rheumatoid wrist are revisited. The effectiveness of operative treatment for midcarpal instability and distal radioulnar joint osteoarthritis continues to be assessed. Sports-related chronic wrist injuries from golf, trampolining, and gymnastics, as well as newer recreational activities such as in-line skating, are rapidly gaining the recognition they deserve.

Algorithms↗
PubMed1997

Load mechanics of the wrist.

During the last decade, we have been studying load mechanics under a variety of conditions using pressure-sensitive film and, more recently, three-dimensional reconstructions and motion analysis. In all of these studies using pressure-sensitive film, the simulated pathologic or traumatic conditions that were tested showed that all areas in which an increase in contact area or pressure occurred, localized to one area of one joint, coincided with areas in which degenerative changes occurred in the simulated clinical situation. The areas in which there was a decrease or no change in contact area or pressure coincided with areas that were spared from degenerative changes in simulated clinical situations. More recent work has demonstrated that normal carpal kinematics during wrist flexion and extension do not have an instantaneous screw axis that is fixed in or limited to the capitate. These findings change the understanding previously based on studies suggesting that the center of rotation was fixed in the capitate. It was noted that during global wrist motion the radiolunate joint contributes more motion and flexion than the capitolunate joint, but the capitolunate joint contributes more motion and extension than the radiolunate joint. It also was demonstrated that translational motion is a normal component of carpal kinematics.

Biomechanical Phenomena↗
PubMed1997

Normal wrist kinematics and the analysis of the effect of various dynamic external fixators for treatment of distal radius fractures.

The purpose of this study was to evaluate the effect that external fixation devices used for distal radius fractures have on normal carpal kinematics, using high speed video data acquisition. Cadaver forearms were stabilized, allowing free excursion of the wrist for passive range of motion. Synergistic muscle tension was simulated by looping the extensor and flexor pairs of the wrist. Global wrist flexion and extension, intercarpal angles, and the instantaneous screw axis (ISA) were studied. These parameters allowed a quantification of normal carpal kinematics and comparison to the kinematics of the carpal bones with external fixators attached. This study shows that normal carpal kinematics during wrist flexion and extension do not have an ISA fixed in or limited to the capitate. In addition, the ISA data provide evidence that translational motion is a real and measurable component of normal carpal motion. This would change the understanding of carpal kinematics in previous studies that suggested that the center of rotation was fixed in the capitate. The proximal carpal (radiolunate) joint contributes more motion (has a greater rotation angle) in normal global wrist flexion and the midcarpal (capitolunate) joint contributes more motion in normal global wrist extension. In addition, the global range of motion and intercarpal joint angle of the wrist are limited with the application of any of the external fixators tested. None of the external fixators allowed normal ISA vector surfaces during wrist motion.

Adult↗
PubMed1996

A multicenter prospective review of 640 endoscopic carpal tunnel releases using the transbursal and extrabursal chow techniques.

A prospective study involving eight institutions was performed, incorporating 640 cases of carpal tunnel release using a dual portal endoscopic technique. The original transbursal technique described by Chow was used in 110 cases (17%), and the modified extrabursal technique was used in 530 cases (83%). An overall complication rate of 11% was found in the patients in whom the transbursal technique was used, compared with 2.2% in the patients in whom the extrabursal technique was used. The return-to-work status was followed in 291 cases (199 non-worker's compensation cases and 92 worker's compensation cases). The worker's compensation patients returned to work in an average of 57 days, compared with 22 days for non-worker's compensation patients. This study suggests the extrabursal dual portal endoscopic technique is associated with fewer complications than the transbursal approach, and patients covered by worker's compensation return to work later than non-worker's compensation patients.

Adolescent↗
PubMed1996

Multiple angiolymphoid hyperplasia with eosinophilia of the hand: report of a case and review of the literature.

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare angioproliferative disorder with a predilection for the head and neck region. ALHE is very rare in the extremities and even more rare in the hand, with only single cases reported in this location. We describe the occurrence of multiple lesions of ALHE on the right hand of a 26-year-old woman. We report this unusual occurrence and convey a clinical differential diagnosis with other benign and malignant conditions of the hand. All the lesions of the palm were excised out as a unit, the subungual lesion removed completely, and the involved segment of the right common digital artery excised. The tissues were processed for routine histologic examination as well as for histochemical and immunohistochemical tests. Electron microscopic study was also performed. Recurrent lesions on the same hand were also excised. Histologic examination of all the lesions revealed classic morphologic features of ALHE. The results of special studies confirmed the endothelial nature of the proliferating cells. ALHE can present as multiple lesions in the hand, and can arise in a subungual location. The possibility of larger arteries being involved should be considered. Recurrent lesions may appear months after the original presentation.

Adult↗
PubMed1995

Extrinsic wrist ligaments in the pathomechanics of ulnar translation instability.

A description of the various combinations of ligament disruptions necessary for ulnar translation instability is presented based on a series of cadaver dissections and load studies. Dissections and load studies demonstrated that major ligament disruption, even to the extent that only the dorsal ulnolunate, the palmar ulnolunate or the radioscaphocapitate, and the long radiolunate ligaments were left intact, failed to result in meaningful ulnar translation of the carpus. The radioscaphocapitate ligament alone could not prevent significant ulnar translation. Palmar translation instability was evident with less ligament disruption than that needed for ulnar translation and was always evident if there was ulnar translation. These studies imply that ulnar translation represents a much more global ligament disruption and instability than previously suggested in the literature.

Aged↗
PubMed1995

Carpal bone anatomy measured by computer analysis of three-dimensional reconstructions of computed tomography images.

Using quantitative analysis of three-dimensional reconstructions of computed tomography scan data, a normative database of carpal bone morphology was built. Thirty-five wrists were imaged in a computed tomography scanner. Each slice was processed to determine the bone edges and assembled as a three-dimensional model by stacking. Quantitative measurements of volume, surface area, maximum length, and intercarpal distances were then assessed. A reliable three-dimensional carpal height ratio was calculated by dividing the carpal height (minimum distance between the fourth metacarpal and the radius) by the capitate maximum length. For volume, maximum length, and surface area, the order for the eight carpal bones with respect to size (in descending order) were: capitate, hamate, scaphoid, trapezium, lunate, trapezoid, triquetrum, and pisiform. Male wrists were significantly larger than female wrists. There were no significant differences in the relative dimensions between left and right wrists, or between left and right wrists of matched pairs. This technology offers automated analysis of three-dimensional geometric carpal information and the opportunity to obtain a body of information about normal and abnormal morphology as well as spatial relationships between carpal bones.

Adolescent↗
PubMed1995

Quantification of anatomic, geometric, and load transfer characteristics of the wrist joint.

The work reported here is an assimilation of 8 years of research, the purpose of which was to gain a better understanding of the normal and abnormal workings of the wrist joint. The results are summarized in three major areas of concentration: descriptive anatomic studies, which include direct measurements of cadaver specimens, biomechanical loading studies to define load distribution through normal and abnormal wrists, and three-dimensional (3D) anatomy studies using solid models derived from computed tomographic (CT) images of in vivo and cadaver wrists. The descriptive anatomic studies used 393 cadaver wrists to evaluate the incidence and distribution of anatomic features, arthroses, chondromalacia, and soft-tissue lesions. The data were analyzed for any statistically significant associations among different variables. The biomechanical studies characterized the biomechanics of the human wrist in a variety of normal, simulated traumatic, and surgically treated conditions. The results of the load studies have provided clinically relevant information on the normal anatomy and functional mechanics of the wrist as well as guidelines for the treatment of a number of different fractures and ligament injuries. The 3D anatomic studies use quantitative analysis of 3D reconstructions of CT scan data to build a normative database of carpal bone morphology. Thirty-five wrists were imaged in a CT scanner. Quantitative measurements of volume, surface area, maximum length, and intercarpal distances were than assessed. A reliable 3D carpal height ratio (3DCHR) was calculated by dividing the capitate maximum length by the carpal height, which is the minimum distance between the fourth metacarpal and the radius.

Adolescent↗
PubMed1995

Wrist arthroscopy.

Explore the source record for details and available documents.

Arthroscopes↗
PubMed1994

Variability at the carpometacarpal and midcarpal joints involving the fourth metacarpal, hamate, and lunate in catarrhini.

Intraspecies variability is investigated in two regions of the wrist, for the purpose of determining whether patterns may be discerned in the variability that may be compared in the functional and phylogenetic analysis of living and fossil catarrhines. In the midcarpal joint region, two lunatohamate configuration patterns are found, and at the fourth carpometacarpal joint four types of configuration are identified. These two sites previously were reported to show almost continuous variability in humans, thus precluding comparison with other species. The different types of configuration in our study are delineated on the basis of their relation to differences in joint function. At the lunatohamate site there is a strong tendency in each species examined for one type to dominate in frequency. At the fourth carpometacarpal joint there is a tendency for one type or for two related types to predominate in each species. The chimpanzee sample exhibits the least variability of all species studied in joint configuration at the two sites. Australopithecus afarensis has a combination of joint types in these regions likely to be found today in only a small percentage of living Hominoidea. We conclude that patterns may be discerned at some joints in what was formerly considered to be a continuum of variation. Since these patterns (joint types) differ in their relative frequencies among living species, the frequency differences may be useful as a guide to the reconstruction of phylogenetic relationships and of potential wrist functions in fossil species.

Animals↗
PubMed1994

Limited arthrodesis for scaphoid nonunion.

A new surgical technique is described for the treatment of longstanding scaphoid nonunions with established degenerative changes and carpal malalignment. The technique is based on natural history and biomechanical studies and includes the excision of the distal scaphoid fragment and a limited arthrodesis that incorporates the proximal pole of the scaphoid, the lunate, and the capitate. Six men were treated with the procedure for symptomatic chronic scaphoid nonunions, and all limited arthrodeses fused. Pain relief was good to excellent, and range of motion averaged 50% of the contralateral side.

Adult↗
PubMed1994

A comprehensive study of pressure distribution in the ankle joint with inversion and eversion.

The understanding of load transfer characteristics is the baseline for biomechanics of the ankle joint. Changes in contact patterns of the articular cartilage from the norm may indicate pathologic conditions. Measurement of the contact in human cadaver ankles provides a direct measurement for this understanding. The force transfer characteristics of the three facets of the ankle joint were investigated. Five fresh-frozen cadaver lower extremities were tested in 12 positions under three axial loads of 490, 686, and 980 N. Fuji film served as the pressure transducer and the prints were analyzed by a computerized video digitizer. The results demonstrated that as the foot was moved into inversion or eversion with the ankle in neutral flexion or dorsiflexion, there was a decrease in total contact area and an increase in the average high pressure. In plantarflexion, the contact area was lower and the average high pressure was higher, indicating a greater force per unit area as compared with dorsiflexion and neutral flexion. In plantarflexion, however, little change was noted with inversion or eversion. In dorsiflexion, the total contact area was higher and the average high pressure slightly lower as compared with neutral flexion. With inversion, the contact area of the medial facet of the ankle increased and with eversion it increased on the lateral facet, especially in dorsiflexion. With an increase in loading, the pressure did not significantly increase but the contact area did increase. The centroid of the contact moved anteriorly to posteriorly on the talus as the joint moved from dorsiflexion to plantar-flexion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗