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At least 631 records · Page 35Linked to original sources
PubMed1993

[Measurement of the radius of corneal curvature with the Maloney surgical keratometer and an on-line keratometer imagery processing system].

A system for measuring the radius of the corneal curvature using the Maloney surgical keratometer (Keratoring), designed for prescribing contact lenses in cases in which it is not possible to measure the radius of the corneal curvature by conventional methods, was tested, and its precision and practicality were evaluated. The subjects were 67 eyes in 34 healthy adults and steel globes for photokeratometer calibration with radii of curvature of 6.73 mm, 7.91 mm and 9.07 mm. The Placido ring projected by the Keratoring was first transmitted to video image processing board via a video unit, and the image was analyzed using a program developed by the authors. Measurements of the globes were possible within a range of error of +/- 0.05 mm, enabling extremely precise analysis. Furthermore, when the average radius of the corneal curvature of human corneas was measured, deviation from the ophthalmometer reading was within 0.2 mm in 87% of cases. When minor meridians were compared, it was found to be possible to measure to within 0.3 mm in 90% of cases. It therefore appears appropriate to apply this method as an index for prescribing contact lenses, especially in cases where conventional methods cannot be performed.

Adult↗
PubMed1993

[Distal intra-articular radius fractures. Indications for and technique of open reduction and plate osteosynthesis].

In the past few years we have seen vast changes in both the assessment and the management of fractures of the distal radius. This is attributable to several factors. On the one hand, conservative treatment has shown poor results in a considerable number of patients, and on the other hand, more and more young patients are presenting with this common lesion. Furthermore, the spread of new methods of osteosynthesis and of modern materials, such as implants, etc., have greatly improved the results of operative procedures, even in complicated fractures of the radius. Therefore, in certain types of fractures far better functional results can be achieved by open reduction. Particularly in intra-articular fractures of the distal radius with or without compression zones and/or injury to the ligaments closed manipulation and subsequent immobilization by plaster is only partially successful. To achieve successful repair of the complex mechanisms in the wrist and the distal radio-ulnar jacket (DRU) joint, these fractures mostly require open reduction and plate fixation including additional support for the articular surface by a cortico-cancellous bone graft from the iliac crest. This enhances the stability of the reduced fragments and facilitates early mobilization which, in turn, greatly improves the functional results. In palmar displaced fractures a palmar approach is employed for both surgical repair and plate fixation, while dorsal compression fractures are reduced, filled and stabilized using a dorsal approach. In this study a special operative procedure for intra-articular comminuted fracture is described. A palmar approach is employed for fracture reduction, while the compression zone is filled by bone graft via an additional dorsal incision.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1996

Determination of the radius of curvature of the anterior lens surface from the Purkinje images.

A new method for calculating the radius of curvature of the anterior surface of the crystalline lens from the measured heights of the Purkinje image PI and PIII is given. Equations are developed for determination of the radius of curvature of the equivalent mirror for three configurations commonly used in phakometry. The method can be applied to targets at any distance from the corneal vertex, for both a stationary target mounted independently of the camera, and for a mobile source attached to the camera where the distance of the target to the corneal vertex will change as the camera is refocused from image PI to PIII. The situation where only one recording is made of images PI and PIII, where the camera is focused on image PI, and the height of the defocused image of PIII is measured is also considered. The errors in calculating the anterior lens radius with the equivalent mirror method if no allowance is made for an object at a finite distance is examined. The new method described is an alternative to collimating targets to overcome the errors in phakometry that occur with targets at finite distances.

Lens, Crystalline↗
PubMed1982

The fracture of the proximal end of the radius in adolescence.

According to a follow-up of 50 fractures of the proximal end of the radius in adolescence the cause and prevention of later persisting functional disturbances, posttraumatic valgisation of the elbow axis and posttraumatic growth disturbances are investigated. Furthermore, the limitations of spontaneous correction of malposition in this area during further growth should be defined. Contrary to current opinion prevailing till now in the literature, not the primary tilt, but the performed therapy turned out to be the cause for later functional disturbance: we found significantly more frequently functional restriction of pro-supination after closed or open repositions than after primary casts without any reposition. The primary malposition of the fracture has no influence on this result just as little as the remaining malposition at consolidation. Furthermore, we noted that the spontaneous correction of malposition in further growth is far more than assumed up to now: all still noticeable malpositions at consolidation up to maximum 65 degrees were corrected again spontaneously in further growth. The posttraumatic valgisation of the elbow axis showed no dependence most of all upon therapy or malposition. According to the results we recommend the following therapeutical procedure for this fracture, using to the full the correcting forces of the growing skeleton, noe performing any reposition, neither closed nor open. With that, the posttraumatic disturbance of nutrition of the proximal end of the radius should be kept to a minimum, furthermore the frequency and extent of the restriction of prosupination diminished resp. avoided. For tilts over 60 degrees as well as displacements and latus over half the width of the shaft we recommend open reposition, if possible without any fixation.

Adolescent↗
PubMed1990

Fracture incidence and bone mineral density of the distal radius in Japanese children.

The incidence of fractures of the distal radius in Japanese persons under 20 years of age was determined, and the bone mineral density of the radius was measured in 236 healthy Japanese children. The peak incidence of fractures occurred at 13 years of age (807 per 100,000) in boys and at 11 (300 per 100,000) in girls. Bone mineral density increased with age, but the rate of increase was not equal at the metaphysis and the diaphysis in the parapubertal period. The metaphyseal/diaphyseal ratio of bone mineral density was lowest at the age of 12-13 years in boys and 11 years in girls. The age at the peak incidence of fractures thus coincided with the age at which the metaphyseal/diaphyseal density ratio was lowest. Thus, it is suggested that low bone mineral density at the metaphysis may be the cause of the high incidence of these fractures in adolescence.

Adolescent↗
PubMed1988

Corrective osteotomy of the distal radius after fracture to restore the function of wrist joint, forearm, and hand.

Eighty-two patients suffering from a severe deformity of the distal radius were operated on in the course of the past 7 years. The corrective osteotomy was done by implanting a corticocancellous bone graft to restore the correct angle of the joint surface and the correct length of the radius. In addition to this, a buttress T-plate was used, which could be removed 6 months later. In 80% of the cases the results with regard to the function of the patients' hands were good. The operative technique is standardized. It is possible to perform this kind of operation on patients of any age, and the procedure can check Sudeck's atrophy. When the obvious disability of the forearm is corrected the mobility of the wrist joint is simultaneously improved.

Adolescent↗
PubMed1991

[Behavior of the joint surface of the distal radio-ulnar joint in malposition of the distal radius].

Pathological changes of wrist bones and ligaments after radial fracture loco typico induce permanent functional restriction and pain. In this paper the effects of malunion on the distal radioulnar joint are investigated and osteotomic therapy of Kienböck's disease gets a new evaluation. By simulating radial malunions on anatomic forearm specimen the effects of these malunions on the contact area during supination, neutral position and pronation are measured. Isolated posttraumatic radial shortening as well as epiphyseal inclination and torsion cause a reduction of radioulnar contact. During supination and pronation the loss of radioulnar contact increases. Most significant reduction of contact takes place at a lower graduation of radial malunion. Pronatory torsion of distal radius compensates for a radioulnar contact reduction from combining dorsal inclination with radial shortening. One conclusion of this paper is an exact restitution of anatomical relations between ulnar head and radial notch after fracture of the distal radius.

Biomechanical Phenomena↗
PubMed1994

Predicting palmar radio-carpal ligament disruption in fractures of the distal articular surface of the radius involving the palmar cortex.

12 adult cadaver wrists were dissected to identify the regions of origin of the four palmar radio-carpal ligaments. A non-dimensionalized value, called the radio-carpal ligament ratio (RLR), was defined as the width of ligament origin from the radius divided by the length of the capitate. Both values were measured directly from radiographs of the cadaver specimens. The RLRs for the four palmar radio-carpal ligaments were found to be statistically consistent. We applied the RLR concept retrospectively to 20 wrists with intraarticular distal radius fractures requiring open reduction. It was found that those fracture patterns in which the fracture fragment ratios (FFR: widths of the fracture fragments divided by the length of the capitate) were outside the limits of corresponding RLRs had clear intra-operative evidence of palmar radio-carpal ligament disruption, while those with FFRs within the limits of corresponding RLRs were noted to have no ligament disruption.

Adult↗
PubMed1988

Trapezoidal osteotomy of the distal radius for unacceptable articular angulation after Colles' fracture.

Loss of radial palmar tilt in malunion of Colles' fractures alters wrist biomechanics, abnormally loading the tenuous dorsal ligament complex. This can result in midcarpal instability with synovitis, pain, weakness, and possible articular degeneration. An osteotomy to correct radius alignment using a trapezoidal corticocancellous bone graft has been devised. The graft is harvested from the dorsal radius adjacent to the osteotomy and malunion site. When turned 90 degrees, a properly designed trapezoidal graft restores radial length, inclination, and palmar tilt in one step. Functional results in 15 patients at 46 months (range, 18 to 116) were comparable with a series using iliac crest graft and plate- and-screw fixation. This simple technique avoids disruption of the extensor retinaculum and reoperation for hardware removal as Kirschner-wire fixation proved adequate.

Adolescent↗
PubMed2007

Do radiographic indices of distal radius fracture reduction predict outcomes in older adults receiving conservative treatment?

AIM: To investigate whether radiographic deformities suggesting inadequate reduction would be associated with adverse clinical outcomes. MATERIALS AND METHODS: Consecutive patients over 50 years of age (n=74) with non-operatively managed distal radius fractures were enrolled in a prospective cohort study. They had radiographs at cast removal ( approximately 6 weeks) and completed DASH (Disabilities of the Arm, Shoulder and Hand), SF-12 (health-related quality of life), and satisfaction surveys 6-months post-fracture. A reference-standard musculoskeletal radiologist, blinded to outcomes status, measured palmar (dorsal) tilt, radial angle, radial height, ulnar height, and intra-articular step and gap. Radiographic indices were correlated to each other and to the various patient-reported outcomes in univariate and multivariate regression analyses. DASH score was the primary study outcome. RESULTS: Of the cohort studied (n=74, mean age 68.5 years, primarily white women), 71% had at least one "unacceptable" radiographic deformity by traditional criteria. Acceptable reduction varied from 60-99% depending on which single index was reported, and 44% of patients had more than two indices reported as unacceptable. Despite these radiographic findings, 6-months post-reduction, self-reported disability was low (DASH=24+/-17), health-related quality of life was near normal, and 72% were satisfied with their care. No radiographic index of wrist deformity (alone or in combination) was significantly correlated to any of the patient-reported outcomes. CONCLUSION: Self-reported outcomes in older adults with conservatively managed wrist fractures were not related to the "acceptability" of radiographic fracture reduction. The proportion of acceptable reductions varied by 40% depending on which index was reported. Consequently, detailed reporting of these indices in older adults with distal radius fracture may be inefficient or perhaps even unnecessary.

Aged↗
PubMed2005

Volar plate fixation of distal radius fractures.

Volar fixed angle fixation may be considered as the beginning of a new era in restoring wrist function to patients with dorsally displaced distal radius fractures even in the face of comminuted or osteopenic bone. A thorough understanding of the anatomy of the wrist is a prerequisite when volarly approaching dorsally displaced distal radius fractures. The demonstration of the device theoretical and practical advantages requires an appreciation of the basics of working length, principles of plate stability, and the effect of cantilever bending. Volar fixed angle fixation successfully improves wrist function and significantly prevents the complications of the dorsal approach previously intractable to treatment. The current advantages, indications, clinical results, and complications of this new technology are being reviewed.

Biomechanical Phenomena↗
PubMed1997

The effects of distal radius fracture malalignment on forearm rotation: a cadaveric study.

Seven fresh cadaveric specimens were used to determine the loss of forearm rotation with varying distal radius fracture malalignment patterns. Uniplanar malunion patterns consisting of dorsal tilt, radioulnar translation, or radial shortening were simulated by creating an osteotomy at the distal end of the radius, orienting the distal fragment position using an external fixator, and maintaining the position with wedges and a T-plate. Rotation of the forearm was produced by fixing the elbow in a flexed position and applying a constant torque to the forearm using deadweights. Forearm rotation was measured with a protractor. Dorsal tilt to 30 degrees and radial translation to 10 mm led to no significant restriction in forearm pronation or supination ranges of motion. A 5-mm ulnar translation deformity resulted in a mean 23% loss of pronation range of motion. Radial shortening of 10 mm reduced forearm pronation by 47% and supination by 29%.

Biomechanical Phenomena↗
PubMed1997

The use of frozen-allograft radial head replacement for treatment of established symptomatic proximal translation of the radius: preliminary experience in five cases.

Five patients with disabling symptoms related to proximal translation (> 1 cm) of the radius following radial head excision (Essex-Lopresti lesion) were treated with implantation of a frozen-allograft radial head prosthesis. Following restoration of neutral ulnar variance at the wrist, a size-matched frozen radial head allograft was implanted and secured to the proximal radius with internal fixation. In three patients, this was a two-stage procedure; radial length was restored gradually using an ilizarov external fixation device and the allograft was placed later. Patients were evaluated clinically and radiographically at a mean follow-up time of 3 years (range, 1-7 years). All patients had relief of wrist and elbow pain and were satisfied with the outcome of the operation. Forearm rotation improved by a mean of 37 degrees and wrist motion improved by a mean of 45 degrees. Forearm reconstruction with frozen radial head allograft implantation may be a beneficial method of treatment for this difficult problem.

Adult↗
PubMed2002

Estimation of distal radius failure load with micro-finite element analysis models based on three-dimensional peripheral quantitative computed tomography images.

There is increasing evidence that, in addition to bone mass, bone microarchitecture and its mechanical load distribution are important factors for the determination of bone strength. Recently, it has been shown that new high-resolution imaging techniques in combination with new modeling algorithms based on the finite element (FE) method can account for these additional factors. Such models thus could provide more relevant information for the estimation of bone failure load. The purpose of the present study was to determine whether results of whole-bone micro-FE (microFE) analyses with models based on three-dimensional peripheral quantitative computer tomography (3D-pQCT) images (isotropic voxel resolution of 165 microm) could predict the failure load of the human radius more accurately than results with dual-energy X-ray absorptiometry (DXA) or bone morphology measurements. For this purpose, microFE models were created using 54 embalmed cadaver arms. It was assumed that bone failure would be initiated if a certain percentage of the bone tissue (varied from 1% to 7%) would be strained beyond the tissue yield strain. The external force that produced this tissue strain was calculated from the FE analyses. These predictions were correlated with results of real compression testing on the same cadaver arms. The results of these compression tests were also correlated with results of DXA and structural measurements of these arms. The compression tests produced Colles-type fractures in the distal 4 cm of the radius. The predicted failure loads calculated from the FE analysis agreed well with those measured in the experiments (R(2) = 0.75 p < 0.001). Lower correlations were found with bone mass (R(2) = 0.48, p < 0.001) and bone structural parameters (R(2) = 0.57 p < 0.001). We conclude that application of the techniques investigated here can lead to a better prediction of the bone failure load for bone in vivo than is possible from DXA measurements, structural parameters, or a combination thereof.

Aged↗
PubMed1996

Retrospective study on the usefulness of radius and lumbar bone density in the separation of hemodialysis patients with fractures from those without fractures.

We measured bone mineral density (BMD) at the lumbar spine (LS-BMD), 1/3 radius (1/3R-BMD), and ultradistal radius (UDR-BMD) in 59 men (4 with spine fractures and 4 with nonspine fractures) and 65 women (10 with spine fractures and 9 with nonspine fractures), all receiving maintenance hemodialysis (HD). The BMD at each site expressed absolutely in g/cm2 was significantly lower in women than in men (p = 0.0001). In men, the absolute and age-matched values of both 1/3R- and UDR-BMD were inversely and significantly correlated with the duration of HD, and with serum alkaline phosphatase and parathyroid hormone levels (p < 0.05), whereas such relationships were obscure in women. On the other hand, the absolute values of BMD at each site in women but not in men were inversely and significantly correlated with patient age (p < 0.001). In both sexes, R-BMD was significantly lower in both the spine and nonspine fracture groups than in the nonfracture group (p < 0.05 and p < 0.01, respectively), whereas the only significant difference in LS-BMD was that it was lower in women with spine fractures than in women without fractures, when expressed as its absolute value (p < 0.05). By receiver operating characteristic analyses, both the absolute and age-matched values of R-BMD were better than LS-BMD as a determinant of non-spine fracture histories, and were similar to absolute LS-BMD as a determinant of spine fracture histories. We conclude that R-BMD is more valuable than LS-BMD for discriminating HD patients with all types of fractures from those without fractures.

Adult↗
PubMed2000

Osseous integration of bovine hydroxyapatite ceramic in metaphyseal bone defects of the distal radius.

Hydroxyapatite ceramic made of bovine spongiosa was used as structural support material in a prospective study to correct bone defects experienced after reduction in distal radius fractures. The study took place over a 3-year period (1992-1999) and comprised 14 patients. Osseous integration was analyzed via biopsies and magnetic resonance imaging. Long-term follow-up monitoring involving magnetic resonance imaging in 13 of the 14 patients showed fibrovascular growth within incorporated hydroxyapatite material. Osseous integration was demonstrated in magnetic resonance images by gadolinium uptake and by the presence of osteoid layers and endothelialized vessels. Hydroxyapatite ceramic offers a biologically acceptable alternative to autologous bone when augmenting distal radius fracture fixation.

Adult↗
PubMed2000

Comparison of three different plating techniques for the dorsum of the distal radius: a biomechanical study.

Three different plating techniques were used on experimentally produced dorsally displaced distal radius fractures in cadavers and were tested in 4-point bending: a AO 3.5-mm T plate (group 1), two 2. 0-mm titanium plates 60 degrees to each other (group 2), and the AO pi plate (group 3). A metaphyseal defect was simulated by a dorsally open wedge osteotomy. The tests show that the 2-mm double-plating technique has superior stiffness and statistically equivalent bending and bone gap to failure compared with the AO 3.5-mm T plate or the pi plate when applied to the unstable distal radius fracture model. (J Hand Surg 2000; 25A:29-33.

Biomechanical Phenomena↗
PubMed2001

Distraction lengthening of the radius for radial longitudinal instability after distal radio-ulnar subluxation and excision of the radial head: a case report.

The results of late surgery for symptomatic proximal migration of the radius after resection of the radial head for trauma are usually disappointing. Ulnar variance increases when the interosseous membrane is disrupted. Its integrity should be assessed to predict the results of further surgery. We describe a 29-year-old patient in whom distraction lengthening of the radius through an Ilizarov frame allowed him to regain pain-free function of the wrist and elbow after a complex Essex-Lopresti fracture dislocation and late symptoms of ulnar carpal impingement.

Adult↗