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At least 19 recordsLinked to original sources

Activity of identified wrist-related pallidal neurons during step and ramp wrist movements in the monkey.

1. The activity of globus pallidus (GP) neurons (n = 1,117) was studied in two monkeys to reexamine the relation of neuronal activity to movement type (slow vs. fast) while they performed both a visually guided step and ramp wrist tracking task. To select neurons specifically related to wrist movements, we employed both a somatosensory examination of individual body parts and a statistical analysis of the strength of temporal coupling of neuronal discharges to active wrist movement. 2. Neuronal responses to somatosensory stimulation were studied in 1,000 high-frequency GP neurons, of which 686 exhibited clear responses to manipulation of body parts. Of the latter, 336 responded to passive manipulation of forelimb joints and 58 selectively to passive flexion or extension of the wrist. 3. In the external segment of GP (GPe), most neurons responding to passive wrist movement were found to be clustered in four to five adjacent, closely positioned (separated by 200 microns) tracks in single coronal planes. The clusters were irregular in shape with a maximal width of 800-1,000 microns. Separate clusters of neurons responsive to passive wrist movement were identified in planes 3 mm apart in one monkey and in planes 500 microns apart in the other. Multiple clusters of neurons were also found for neurons responsive to joints other than the wrist. These findings suggest a more discrete and complex representation of individual joints in the primate GP than previously conceived. 4. During the performance of the wrist flexion and extension task, 92 neurons showed clear and consistent changes in activity. For these neurons we measured, with a statistical method on a trial-by-trial basis, the strength of temporal coupling between the onset of active wrist movement and the onset of change in neuronal discharge rate. Fifteen neurons showed changes in activity time-locked to the onset of active wrist movement. 5. Twelve pallidal neurons were classified as "wrist-related" based on their movement-locked changes in discharge during task performance and their clear responses to passive wrist joint rotation on examination. All of these neurons exhibited statistically significant modulation of their discharge rate during both fast (peak velocity 97-205 degrees/s) and slow (peak velocity 20-62 degrees/s) wrist movements in the task. The amplitudes of modulation were larger during fast wrist movement than slow movement. These results suggest that the basal ganglia motor circuit plays a similar, rather than an exclusive, role in the control of slow and fast limb movements.

Animals

Electromyographic reflexes evoked in human wrist flexors by tendon extension and by displacement of the wrist joint.

1. The electromyographic (EMG) reflexes evoked in the wrist flexor muscle, flexor carpi radialis (FCR), by percutaneous extension of its tendon and by forcible extension of the wrist joint have been studied. Reflexes were elicited during steadily maintained voluntary flexor contraction of 10% of each subject's maximum. 2. Tendon extension, using 'ramp and hold' displacements, evoked fairly prolonged (ca 50 ms) increases in EMG activity. These responses were usually subdivided into two main excitatory peaks of respectively short (SL, ca 20 ms) and long (LL, ca 45 ms) latency. This pattern contrasted with that observed following brief tendon taps when only a single, SL peak was elicited. 3. 'Stretch' reflexes evoked by 'ramp and hold' wrist extensions, as has been noted by numerous earlier investigators, were also protracted and comprised two main excitatory components. These responses resembled those produced by tendon extension both in their general form and in their behaviour upon altering the velocity of mechanical stimuli. Quantitatively, however, two main differences were evident. The reflexes evoked by wrist extension, including their SL and LL peaks, were generally somewhat larger. Additionally, when parameters of the two modes of stimulation were adjusted to elicit SL responses of equivalent amplitude, the LL responses elicited by tendon extension were regularly smaller and of shorter duration than those elicited by wrist extension. 4. Termination of the two forms of mechanical stimulation, by releasing tendon or wrist extension, each elicited a SL reduction in EMG activity. Such troughs were more pronounced and more consistently observed upon release of wrist extension. 5. Neither local anaesthesia of the skin overlying the flexor tendons at the wrist nor ischaemia of the hand and lower forearm produced any systematic modification of reflex response patterns. 6. It is concluded that intramuscular receptors (presumably muscle spindles) in FCR mediate both the SL and LL reflexes evoked in this muscle by extension of its tendon. Intramuscular receptors also seem certain to be very largely responsible for the EMG responses generated in this muscle by wrist extension.

Action Potentials

Rheumatoid wrists treated with synovectomy of the extensor tendons and the wrist joint combined with a Darrach procedure.

Forty-three rheumatoid wrists in 43 patients with bilateral wrist involvement were treated with synovectomy of the extensor tendons and wrist joint combined with a Darrach procedure in the period from 1966 to 1986. Clinical and radiologic assessment of the wrists was carried out after an average follow-up period of 11 years, with comparison of the treated and the opposite untreated wrists. The authors confirmed what others have concluded regarding the operation: pain was generally decreased, forearm rotation increased, and wrist extension and palmar flexion changed little. Radiologically, carpal collapse and palmar carpal subluxation progressed nearly parallel to the opposite wrists, but ulnar carpal shift was much greater in the surgically treated wrists. Therefore it is suggested that some measure to prevent ulnar carpal shift, such as Clayton's tendon transfer or radiolunate arthrodesis, should be included in this operation.

Adult

Roentgenographic examination of the wrist: a systematic study of the normal, lax and injured wrist. Part 2: Stress views.

The standard and positional views of 53 normal wrists have been compared to views taken under stress. The stresses applied can be divided into normal and abnormal ones. All the injured wrists with pathological roentgenographic appearances were operated on and thus the findings confirmed. Roentgenographic examination of the wrist under stress appears to be a valuable and reliable diagnostic aid. Two types of laxity of the wrist and a radio-anatomical classification of wrist instabilities are defined.

Biomechanical Phenomena

Chronic wrist pain: indications for wrist arthroscopy.

Although arthroscopy represents a new and dynamic diagnostic technique for evaluating the wrist, specific indications for arthroscopic intervention in the wrist are not defined. To place this technique in perspective, we review our experience with 54 consecutive arthroscopies of the radiocarpal and midcarpal joints in 53 patients with chronic wrist pain. On the basis of this review, we believe arthroscopy is indicated for the diagnosis of wrist pain of longer than 3 months' duration. Defects of the triangular fibrocartilage and lesions of the articular cartilage, including loose bodies, are detectable and easily treated with wrist arthroscopy.

Adolescent

Wrist cysts and fistulae. An arthrographic study of the rheumatoid wrist.

An arthrographic study of the wrist joint, in which 65 rheumatoid wrist joints were satisfactorily shown, gave a high incidence of significant abnormalities even in the absence of clinical signs of wrist involvement. Several synovial protrusion cysts were shown and corresponded to localized clinical swellings on the volar aspect of the wrist joint. These cystic swellings may be apparent before the onset of polyarthritis and may be differentiated from ganglia arthrographically by their association with other features suggesting erosive synovitis. Cystic swelling over the lower end of the ulna is shown to be frequently due to synovial hypertrophy of the inferior radioulnar joint in either a dorsal or volar direction. In one case a fistulous tract was delineated connecting the midcarpal joint with the volar surface of the wrist by a flexor tendon sheath.

Adolescent

Normal bone density of the wrist and spine and increased wrist fractures in girls with Turner's syndrome.

Turner's syndrome is associated with multiple skeletal abnormalities, including osteoporosis. We evaluated the hypothesis that girls with Turner's syndrome may have deficient bone density before the expected age of pubertal onset (9-13 yr) by comparing the bone mineral content of the wrist and lumbar spine in 78 girls with Turner's syndrome (4-13 yr old) and 28 normal prepubertal girls who were matched for age, bone age, body mass index, or height age. The bone mineral content of the wrist and spine was measured by single photon absorptiometry (SPA) and dual photon absorptiometry (DPA), respectively. SPA values for girls with Turner's syndrome vs. normal subjects (4-6.9, 7-9.9, and 10-12.9 yr old) were (mean +/- SD) 0.27 +/- 0.05 vs. 0.36 +/- 0.05, 0.35 +/- 0.06 vs. 0.41 +/- 0.06, and 0.41 +/- 0.05 vs. 0.45 +/- 0.03 g/cm2, respectively. SPA values in the Turner's syndrome girls were decreased compared to those in normal prepubertal girls, matched for age (P less than 0.0001), bone age, (P less than 0.001), and body mass index (BMI; P less than 0.0001), but not for height age. DPA values for girls with Turner's syndrome vs. normal girls in the same age categories were 0.65 +/- 0.06 vs. 0.70 +/- 0.09, 0.77 +/- 0.08 vs. 0.79 +/- 0.09, and 0.83 +/- 0.12 vs. 0.78 +/- 0.07 g/cm2. DPA values in Turner's syndrome girls (as a group) were decreased compared to those in normal prepubertal girls matched for age (P less than 0.05) and BMI (P less than 0.02), but not for bone age or height age. The annual incidence rate of wrist fractures in Turner's syndrome girls (9.1 of 1000) was significantly increased compared to the reported annual incidence rate in normal children (3.5 of 1000; P less than 0.003). We conclude that prepubertal-aged girls with Turner's syndrome (less than 13 yr old) have normal bone density for height age, but significantly decreased bone density of the wrist for chronological age, bone age, and BMI. They also have significantly more wrist fractures than normal girls, but it is not clear that this is related to their bone density.

Absorptiometry, Photon

Neuronal activity in cortical efferent zones projecting to wrist extensors during voluntary wrist extension in the monkey.

Three monkeys were trained to make rapid wrist extension on presentation of a cue light. After training the animal sufficiently, unit activity was recorded from the cortical efferent zones corresponding to the wrist extensors. Most neurons in the wrist extensor zone were increased in their discharge rate during the wrist extension. Their activation pattern, especially the onset time, varied among different neurons. The earliest neuron was activated 65 msec before the EMG onset of the wrist extensors, while the latest did 30 msec after the EMG onset. About 80% of them activated before the EMG onset. In contrast, variation of the discharge onset of each neuron was rather small and 5-15 msec in quartile deviation. These findings may suggest that each neuron in the cortical efferent zone functions in different timing in the voluntary phasic contraction of the target muscle.

Animals

The rheumatoid wrist: patterns of disease progression. A review of 50 wrists.

50 wrists in 28 patients have been followed in a retrospective radiographic review for a mean period of 9.56 years. Patterns of disease and the rates of change in the severity of the disease have been determined, with particular reference to the changing relationship in time between involvement of the wrist and hand. In the wrist, there was relative sparing of the mid-carpal joint, with a significant correlation between a high incidence of triquetro-lunate disease and changes in the ulnar styloid. Wrist disease was found to "protect" the hand for the first five years but not after this time. On the basis of these results, earlier surgical intervention is proposed, with the intention of shifting the emphasis of surgery from salvage to prophylactive or reconstructive procedures.

Arthritis, Rheumatoid

Preliminary results of total wrist arthroplasty in rheumatoid arthritis using the Trispherical total wrist arthroplasty.

Thirty-two patients underwent 38 arthroplasties for advanced rheumatoid arthritis and marked soft tissue losses. Seven wrists required repair or transfer of at least one tendon for rebalancing. All patients were improved by the implants. Thirty-four of the 38 patients were improved beyond the functional level of a painless wrist arthrodesis. Overall, there were 23 excellent, 10 good, 3 fair, and 2 poor results. The average wrist score was 90.3 points, and the average arc of motion was 38 degrees. There were three cases of migration of the third metacarpal stem and nine cases of lucency about the stems, three of which were progressive or greater than 1 mm. There were no deep infections. There was one reoperation for persistent pain and one for component loosening. There were no cases of implant failure. These results indicate that this total wrist arthroplasty is a safe, reproducible procedure for radiographic class III and IV rheumatoid disease and should be considered a first line of therapy for that group.

Adult

Cost effectiveness of wrist fluoroscopy and arthrography in the evaluation of obscure wrist pain.

The cost effectiveness of wrist fluoroscopy and arthrography was evaluated in patients with obscure wrist pain. Dynamic fluoroscopy was performed in 91 cases and was positive in 54 (59%). Radiocarpal arthrography was performed in 60 of these cases in which further information was desired. Arthrography increased the diagnostic yield to 62 of 91 cases (68%). Diagnoses included ligament and cartilage tears, and dynamic intercarpal instability. The cost per positive examination for fluoroscopy, based on total cost for fluoroscopy in 91 patients divided by number of positive cases, is $126. The cost per positive examination by arthrography alone is $377. When arthrography is done only when fluoroscopy is equivocal or negative, the cost per positive examination (fluoroscopy plus arthrography) drops to $280. Wrist arthrography is only cost effective if done after dynamic fluoroscopy fails to answer the clinical questions. When done together in this setting, the two procedures are most cost effective than arthrography alone. Based on current costs, conservative treatment of carpal instability costs about $1,500, and surgical therapy costs about $4,000. Thus, fluoroscopy and arthrography may further reduce the cost of management of obscure wrist pain by identifying those patients who would not benefit from surgical exploration.

Arthrography

[Anatomy of the articular nerves of the wrist. Implications for wrist denervation techniques].

The knowledge of the anatomy of the wrist articular nerves is at the base of the denervation technique. After a dissection of 12 adult wrists, we specify the situation and the relation of these nerves at the level where they are accessible to a surgical approach. The 10 articular branches of Wilhelm are described successively. The posterior interosseous is the most voluminous and most constant. Some branches need a specific surgical approach: anterior and posterior interosseous nerve, lateral cutaneous nerve, articular branch of the first web. Other nerves are cut blindly after skin undermining (perforating branches from cutaneous nerves). Some branches appear inaccessible to a cautious surgery because they are closely tight to other motor branches (deep branches of the cubital nerve). Finally some branches described by Wilhelm were not found in our dissections: branches of the median palmar cutaneous nerve, and direct branch of the cubital nerve.

Classification

Difficult wrist fractures. Perilunate fracture-dislocations of the wrist.

Perilunate dislocations of the wrist have a common pathway of disruption that occurs from extensive dorsiflexion injuries. Open reduction and internal fixation of these injuries is required to provide accurate alignment and the option for ligament repair. Both dorsal and palmar surgical incisions may be indicated. Associated injuries to the median nerve must be recognized. Treatment includes scaphoid and radial styloid stabilization with multiple K-wires or internal compression screw (Herbert or Association for the Study of Internal Fixation [ASIF] screws). In these injuries, the lunate must be reduced first and stabilized. The scaphoid proximal segment follows the lunate unless the scapholunate (SL) ligament is torn. The distal scaphoid fragment, capitate, and triquetrum are reduced and aligned with the lunate and need to be held with K-wires. Ligament repair and augmentation may be necessary at both scapholunate and lunotriquetal areas if there has been serious ligament injury. Palmar ligament repair is often required, and we recommend a palmar exploration in most patients along with release of the median nerve. Surgical treatment results of perilunate fracture-dislocations of the wrist appear better than conservative treatment methods, but complications following both indicate the need for improved internal fixation and fracture-dislocation realignment. These fractures are a real challenge to the treating surgeon who must use patience, precise surgical techniques, and careful roentgenographic study (including tomograms and traction views) to assure the best result.

Adolescent

Rheumatoid synovitis of the volar compartment of the wrist joint: its radiological signs and its contribution to wrist and hand deformity.

The radiological signs that suggest involvement of the volar compartments of the wrist include grooving of the scaphoid, pseudocysts of the distal radius, and scaphoid-lunate dissociation. These indicate involvement of the radiocarpal ligamentous support. This leads to loss of stability of the scaphoid, which then goes into a volar-flexed position, contributing to shortening the radial carpal height and favoring rotation of the carpus into supination, radial deviation of the metacarpals, and ulnar drift of the fingers.

Arthritis, Rheumatoid

Results of treatment of extensive volar wrist lacerations: the spaghetti wrist.

A series of 38 volar wrist lacerations is reviewed with regard to epidemiologic aspects and results. In general, return of tendon function was quite good, and return of nerve function in this series was also satisfying. We attribute the generally good results to immediate repair of all structures, microscopic repair of significant arterial injuries, microscopic grouped fascicular nerve repair, early mobilization (dynamic splinting and intensive occupational therapy), and a generally youthful group of patients. Review of this series has strengthened our opinion that aggressive primary repair of all injured structures is appropriate for these extensive lacerations.

Adolescent