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Comparison of the radius of curvature of the ulnar trochlear notch of Rottweilers and Greyhounds.

OBJECTIVE: To compare radius of curvature along the ulnar trochlear notch of Rottweilers and Greyhounds to determine whether morphologic differences exist that may contribute to the cause and pathogenesis of fragmented coronoid process in Rottweilers. SAMPLE POPULATION: Paired elbow joints from 13 Rottweilers and 14 Greyhounds. PROCEDURE: Elbow joints were radiographically scored on the basis of severity of osteoarthritic lesions. The articular contour of each ulnar trochlear notch was digitized. The radius of curvature at defined points along the ulnar trochlear notch was compared between breeds. RESULTS: Radius of curvature of the ulnar trochlear notch was not a constant function of arc length in either breed but had a consistent characteristic appearance in both breeds. Radius of curvature was greatest at each end of the ulnar trochlear notch and had 2 peaks in the midportion of the notch in both breeds. These peaks occurred farther distally in the notch and were larger in Rottweiler ulnae than Greyhound ulnae. A significant difference in mean radius of curvature was detected between breeds at these peaks. Greyhounds had significantly greater mean radius of curvature at the end of the medial coronoid process, compared with Rottweilers. CONCLUSIONS AND CLINICAL RELEVANCE: Radius of curvature of the ulnar trochlear notch is a complex function of arc length in Rottweilers and Greyhounds. The waveform has a consistent characteristic appearance in both breeds. Although significant differences were identified between breeds, associations between these differences and cause or pathogenesis of fragmented coronoid process in Rottweilers were not apparent.

Animals↗

Distal radius fracture and the distal radioulnar joint--anatomical considerations.

The ulna represents the non-rotating, stable and weightbearing part of the forearm around which the radius rotates in pronation and supination. The distal radioulnar joint is the distal half of an articulation, the proximal half of which is the proximal radioulnar joint. In spite of the distance between the two, the distal and proximal radioulnar joints together form a bi-condylar joint, the "forearm joint", with the axis of rotation running from the centre of the radial head out distally into the interosseous space towards the centre of the ulnar head. The end of the radius together with the hand and what is held in the hand will rest against the stable, immobile ulnar head, which acts as the keystone of the wrist. Mobility and stability of the distal radioulnar joint is accomplished by the combined action between fully congruent articulating surfaces and intact radioulnar ligaments. Following a distal radius fracture, the semilunar notch of the radius will no longer be congruent to the ulnar head due to the displacement of the distal fracture fragment of the radius into either dorsal angulation, radial angulation, or both. The stabilizing ligaments will tear. Any posttraumatic disabling dysfunction of the distal radioulnar joint should accordingly be treated by a corrective osteotomy of the radius at the fracture site in order to achieve full congruity between the semilunar notch and the ulnar head. Resection of the ulnar head deprives the wrist its keystone and should therefore be avoided.

Biomechanical Phenomena↗

Comparison of the self-expanding Radius stent and the balloon-expandable Multilink stent for elective treatment of coronary stenoses: a serial analysis by intravascular ultrasound.

We compared the outcome of the self-expanding Radius stent and the balloon-expandable Multilink stent serially by angiography and intravascular ultrasound. Successful stent deployment was achieved in 66 lesions of 56 stable angina patients (34 lesions with Radius stents and 32 lesions with Multilink stents). At follow-up, there were no significant differences in minimal lumen diameter or percent diameter stenosis between the groups, nor in restenosis rates, although the Radius stent group rate was slightly lower (23.5% vs. 31.3%). In the Radius stent group, stent cross-sectional area (CSA) increased gradually after implantation until the 6-month follow-up (8.37 +/- 1.83 to 10.16 +/- 2.59 mm(2); n = 15), giving a larger CSA (P = 0.03) than the Multilink stent group, which decreased (9.00 +/- 2.05 to 8.27 +/- 2.15 mm(2); n = 17). The lumen CSA was also slightly larger (6.82 +/- 3.06 vs. 5.84 +/- 1.85 mm(2); P = 0.29) in the Radius stent group. These findings indicated that the Radius stent enlarged progressively after implantation, which might be useful for prevention of restenosis.

Aged↗

Cortical and trabecular bone contribute strength to the osteopenic distal radius.

Fractures of the distal radius are common, especially in postmenopausal women, and their prevalence increases with age. Knowledge of the factors that increase the risk of fracture in this metaphyseal region would have predictive and therapeutic implications. Of particular interest in this study were (a) the relative contributions of cortical and trabecular bone to the strength of the distal radius and (b) the best radiographic features to use as strength indicators. In 21 forearms from fresh cadavera (median age at the time of death, 75 years), single photon absorptiometry and quantitative computed tomography were used to determine bone mineral content (BMC), density (BMC/W), and cross-sectional properties of the radius at distal and midshaft sites. Mechanical testing of the forearms then was used to determine the ultimate force and energy to cause the type of fracture that might be caused by a fall on the outstretched hand. Twelve of the 17 tested specimens sustained a fracture of the distal radius, and five sustained a fracture of the scaphoid. In the group of fractures of the distal radius, we found the cross-sectional area and moment of inertia of the cortical shell at the metaphyseal site to be better correlates of strength than the trabecular area and trabecular moment. In contrast, strength correlated much better with trabecular density than with cortical density. Overall, the best correlates of strength were the BMC and BMC/W at either the distal or proximal site. On balance, these results suggest that the thin cortical shell contributes substantially more to the mechanical strength of the distal radius than has been commonly appreciated.

Aged↗

[Problems of malunited fractures of the distal radius].

The essential problematic of the distal fracture of the radius lies in the quality of its reduction and retention. 35 patients with distal fractures of the radius and strain fractures of the styloid process of the ulna were followed up with regard to their functional and radiological results and their subjective symptoms. Patients with intra-articular fractures were found to have significantly poorer functional results compared to those with extra-articular fractures. 29 out of 35 patients developed a nonunion of the styloid process of the ulna in the form of a compensatory false position with a significant dorsal tilt of the articular surface of the radius. Their functional results were also significantly poorer than those of the other 6 patients. The patients whose radii were shortened by more than 2 mm also had significantly poorer functional results and a median dorsal tilt of 5 degrees of the articular surface. Where the dorsal inclination of the articular surface of the radius exceeded 5 degrees, a significant increase in the scapholunar angle, which averaged 62 degrees, was found. On the basis of these figures, we conclude that in the reduction of the distal fracture of the radius, shortening by not more than 2 mm and a dorsal inclination of the articular surface of the radius, taken laterally, of not more than 5 degrees should be tolerated in order to minimise functional impairments of the wrist.

Fractures, Malunited↗

Precision and intersite correlation of bone densitometry at the radius, tibia and femur with peripheral quantitative CT.

OBJECTIVE: To compare the in situ precision of peripheral quantitative CT (pQCT) at the radius, tibia and femur, and to analyze the intersite correlation, in order to determine whether measurements at the lower extremity reproduce results at the radius or are of additional informative value. DESIGN AND MATERIAL: pQCT measurements were performed in 86 elderly cadavers (mean age 80.5 years) at trabecular and cortical locations in the radius, tibia and femur, determining densitometric (bone mineral content and density) as well as geometric parameters (cross-sectional area, cortical thickness, polar moment of inertia and others). In 14 cadavers, repeated measurements were obtained at all sites on four different days. RESULTS AND CONCLUSIONS: At cortical sites, the precision for the densitometric and geometric variables ranged from 0.4% to 4.3%, and was similar for the radius, tibia and femur. At trabecular locations, the reproducibility of the density measurements ranged from 1.8% to 2.5% at the radius, and from 3.2% to 5.9% at the femur and tibia. The intersite correlation of the total bone mineral content ranged from 0.87 and 0.97 at cortical sites, and from 0.63 to 0.85 at trabecular locations. The trabecular density showed a higher similarity between the tibia and femur (r=0.68-0.78) than between the radius and the lower extremity (r=0.41-0.45). The results demonstrate a substantial heterogeneity of trabecular bone in elderly individuals and advocate measurements directly at the site of clinical or scientific interest.

Absorptiometry, Photon↗

Short-term and long-term site-specific effects of tennis playing on trabecular and cortical bone at the distal radius.

Mechanical loading during growth magnifies the normal increase in bone diameter occurring in long bone shafts, but the response to loading in long bone ends remains unclear. The aim of the study was to investigate the effects of tennis playing during growth at the distal radius, comparing the bone response at trabecular and cortical skeletal sites. The influence of training duration was examined by studying bone response in short-term (children) and long-term (young adults) perspectives. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the radius were measured by DXA in 28 young (11.6 +/- 1.4 years old) and 47 adult tennis players (22.3 +/- 2.7 years old), and 70 age-matched controls (12 children, 58 adults) at three sites: the ultradistal region (trabecular), the mid-distal region, and the third-distal region (cortical). At the ultradistal radius, young and adult tennis players displayed similar side-to-side differences, the asymmetry in BMC reaching 16.3% and 13.8%, respectively (P < 0.0001). At the mid- and third-distal radius, the asymmetry was much greater in adults than in children (P < 0.0001) for all the bone parameters (mid-distal radius, +6.6% versus +15.6%; third-distal radius, +6.9% versus +13.3%, for BMC). Epiphyseal bone enduring longitudinal growth showed a great capacity to respond to mechanical loading in children. Prolonging tennis playing into adulthood was associated with further increase in bone mineralization at diaphyseal skeletal sites. These findings illustrate the benefits of practicing impact-loading sports during growth and maintaining physical activity into adulthood to enhance bone mass accrual and prevent fractures later in life.

Adult↗

Preferential distal radius fracture in right-handed individuals presenting to an ED.

The purpose of this study was to determine whether there is a lateralizing predisposition toward injury in right hand-dominant (RHD) individuals. The distal radius fracture was used as the injury for evaluation because it is easily defined and can be objectively documented by roentgenography. A prospective case-series design was used to include consecutive RHD patients with a distal radius fracture. There were 86 women with an average age of 63.1 +/- 17.9 years and 41 men with an average age of 44.0 +/- 17.6 years with a significant difference between ages (P <.01). Overall, there were 50 right and 77 left distal radius fractures, which was significantly different than a 50:50 split (P <.025). Stratification and logistic regression analysis revealed that age (dichotomized into age greater than 57 or other) and not gender was a significant factor in the determination of left versus right distal radius fracture. No interaction between age and gender was found. After adjustment for gender, the odds of developing a left compared with right distal radius fracture was 2.3-fold greater for the older compared with the younger age group (95% confidence interval, 1.0-5.2). Preliminary evidence suggests a lateralizing predisposition for left distal radius fractures in older compared with younger individuals who are RHD. If this data holds up, finding the etiology/mechanism of this predisposition might help in designing environments to minimize the impact of this injury pattern in the slightly older individual.

Adult↗

Combined fractures of the scaphoid and distal radius: a revised treatment rationale using percutaneous and arthroscopic techniques.

Revision of the treatment rationale for combined fractures of the scaphoid and distal radius is based on evolution of treatment goals. The trend toward early recovery of hand function requires rigid fixation of both fractures before the start ofa hand therapy program. It is clear that prolonged immobilization of the scaphoid fracture jeopardizes early motion protocols for the distal radius. The fixation of unstable distal radius fractures with volar locking plates appears to offer the most stable construct to permit early motion. Evaluation, reduction, and fixation should be accomplished without disruption of the uninjured ligaments required for stable motion or the soft tissue envelope required for healing. Minimally invasive or percutaneous techniques are the meth-ods required. The tools needed are a clear understanding of anatomy, minifluoroscopic imaging units, and small-joint arthroscopy instruments. Many investigators advocate these techniques for scaphoid and distal radius fractures. It is only natural that these techniques should be used for these combined injuries. The key to success is a three-step process: (1)percutaneous reduction of the scaphoid fracture and provisional stabilization with a guide wire placed along its central axis, (2) percutaneous/arthroscopic reduction and rigid fixation of the distal radius fracture to permit early motion, and(3) fixation of the scaphoid fracture. This final step is accomplished by dorsal percutaneous implantation of a cannulated headless compression screw along the central scaphoid axis. Dorsal percutaneous fixation of scaphoid fractures with headless compression screws and rigid fixation of unstable distal radius fractures with a volar lock-ing plate system offer the most secure fixation. This small series suggests that the goals of early recovery of hand function can be accomplished using percutaneous/miniopen techniques for fracture reduction with rigid fixation and minimal risks.

Adolescent↗

Trauma-induced growth abnormalities of the distal radius in three cats.

Three immature cats with growth abnormalities of the distal radius secondary to trauma were presented between July 2001 and July 2003. Initial injuries included a Salter-Harris type II fracture of the distal radial physis in one cat, fractures of the styloid process of the ulna in two cats, and metacarpal fractures in one cat. The cats were between 3.5 and 4.5 months of age at the time of injury. Damage to the distal radial physis resulted in a variable degree of shortening of the radius in all cats. Asymmetrical closure caused widening of the lateral aspect of the radiocarpal joint space in two cats. Elbow incongruity was not observed. One cat was treated with osteotomies of the radius and ulna and realignment of the radius, stabilised with external skeletal fixation. Another was treated by ulnar ostectomy alone. Radius and ulna osteotomies and distraction osteogenesis of the radius were performed in the third cat. Clinical outcome was satisfactory in all three cases.

Animals↗

A biomechanic comparison of an internal radiocarpal-spanning 2.4-mm locking plate and external fixation in a model of distal radius fractures.

PURPOSE: To compare the biomechanic stability of distal radius fracture fixation with a new internal radiocarpal-spanning 2.4-mm locking plate, which acts as an internal distal radius fixator, versus a standard distal radius external fixator. The number of locking screws necessary for adequate fracture fixation was also assessed. METHODS: Ten cadaveric specimens were mounted in a loading fixture with cables attached to the 2 flexor and 3 extensor wrist tendons. A 1-cm osteotomy was created to simulate an unstable distal radius fracture. The radiocarpal-spanning locking plate was fixed to the radius and index metacarpal with 4 screws proximally and 4 distally. The specimen was incrementally loaded through the tendons. Motion at the fracture site was determined. Screws were sequentially removed from the construct, the specimen was again incrementally loaded, and fracture motion was measured. The fixation was then changed to an external fixator, and the loading tests were repeated. RESULTS: Fracture fixation with the radiocarpal-spanning 2.4-mm locking plate was significantly more stable with 4 screws proximally and 4 screws distally (4 x 4) and with the 3 x 3 configuration than with the external fixator in both flexion and extension. The 4 x 4 screw configuration was not significantly different from the 3 x 3 screw configuration. The 4 x 4 screw configuration was significantly more stable than the 2 x 2 and 1 x 1 screw configurations in both flexion and extension. All internal fixator configurations and the external fixator showed more fracture displacement at increasingly higher loads. CONCLUSIONS: Fracture fixation with the new internal radiocarpal-spanning 2.4-mm locking plate is more stable than with a standard distal radius external fixator. Only three 2.4-mm locking screws proximally and three 2.4-mm locking screws distally are required for adequate fixation of the locking spanning plate.

Aged↗

Carpal canal pressures after volar plating of distal radius fractures.

Elevated pressures within the carpal canal are known to occur after distal radius fractures. Controversy exists regarding prophylactic carpal tunnel release after open reduction with internal fixation of distal radius fractures. The purpose of this study was to determine the tissue pressures within the carpal canal after volar plating of distal radius fractures. This study was a prospective, observational, IRB approved research study. Ten consecutive patients undergoing volar plating of distal radius fractures were enrolled. After the distal radius fractures were reduced and fixed with volar plates, slit catheters were inserted into the carpal canals for continuous postoperative pressure monitoring for 24 hours. The maximum recorded pressure was 65 mmHg, which occurred in the only patient with fracture blisters. Peak pressures remained at 40 mmHg or less (range 16-40, mean 29) in all patients without fracture blisters. At the conclusion of data collection, all pressures were at 31 mmHg or less. No patient complained of median nerve dysfunction during the study period. Routine prophylactic carpal tunnel release is not recommended after volar plating of distal radius fractures based on these pressure recordings.

Adult↗

Kinematic and torque-related effects of dorsally angulated distal radius fractures and the distal radial ulnar joint.

PURPOSE: The purpose of this study was to examine the torque required to achieve a full range of motion of the distal radioulnar joint (DRUJ) as a result of increasing dorsal angulation from simulated fractures of the distal radius. Based on this study the accepted amount of dorsal angulation of the distal radius can be determined. METHODS: In 9 fresh cadaver limbs motion of the DRUJ was simulated by a custom motion and loading forearm device. The malunion model of the distal radius was controlled by a specially designed external fixation frame that provided control in 6 degrees of dorsal angulations (N, 0 degrees, 10 degrees, 20 degrees, 30 degrees, and 40 degrees ). The study included an intact and nonintact triangular fibrocartilage complex. RESULTS: This study showed that torque across the DRUJ was affected by the degree of simulated malunion of the distal radius. With more than 30 degrees dorsal angulation the torque across the DRUJ was increased in both muscle loading and unloading conditions. Although significance was not noted, with resistive loading this study showed torque changes with as little as 10 degrees malunion of the distal radius. CONCLUSIONS: We conclude that reduction of distal radius fractures to within 10 degrees of dorsal angulation is needed to allow patients to maintain full forearm and wrist rotation.

Aged↗

The effect of dorsally angulated distal radius fractures on distal radioulnar joint congruency and forearm rotation.

A biomechanical cadaver study was performed to evaluate the effect of dorsally angulated distal radius fractures on the distal radioulnar joint. Frykman I distal radius fractures were simulated, and laxity measurements were taken with and without sectioning the triangular fibrocartilage complex and the interosseous membrane. The findings of this study were threefold. First, measured in terms of radial diastasis, incongruency of the distal radioulnar joint occurred with increasing dorsal tilt of the distal radius. It became most dramatic with a change of more than 20 degrees of dorsal angulation of the distal radius. This corresponds to approximately 10 degrees of dorsal tilt of the articular surface of the distal radius, as measured on an x-ray film. Second, increased dorsal angulation caused interosseous membrane tightness and limited maximum pronation and maximum supination. Third, distal radioulnar joint dislocation did not occur until both the triangular fibrocartilage complex and interosseous membrane were sectioned. These results reveal the importance of anatomic reduction of the distal radius fracture and evaluation of damaged soft tissue structures.

Biomechanical Phenomena↗

Semi-automated evaluation of the cortico-medullar index on radius radiographs: a study in prepubertal girls.

The aim of the study was to validate a non-invasive method allowing a semi-automatic cortico-medullar index (CMI) computation from standard radiographs. Fifty-five radiographs of the non-dominant radius of prepubertal girls (aged 10.12+/-1.47 years) were scanned (100 microm scanning resolution) by the same observer. To detect the grey level peaks, we used the Deriche's recursive filter applied to the grey level gradients and we defined the cortical areas by thresholding (iterative contour detection). The CMI was calculated as cortical areas divided by the total bone area. The reproducibility was tested through the analysis of ten radiographs scanned twice, on 5, 10, 15, 20, 30 and 40 lines at each side of a reference line located at the distal third part of the radius. We used the root mean square coefficient of variation (RMS-CV) as verification. Dual-Energy X-ray (DXA) was used for densitometry measurements of the whole body, and non dominant radius (mid-, distal third and ultra distal). The result attaining the best reproducibility concerned the 15-line position (Mean CMI=0.58+/-0.005 with a 1.36% RMS-CV). CMI correlated significantly with Bone Mineral Density (BMD) (r=0.40, 0.33 and 0.50, P<0.01, respectively, at the whole body, mid- and third distal of the radius), Bone Mineral Content (BMC) (r=0.32, 0.36, 0.34 and 0.35, respectively, at the whole body (P=0.01), mid- (P=0.007), third distal (P=0.01) and ultra distal of the radius (P=0.01)) but not with BMD at the ultra distal of the radius (r=-0.01, P=0.9). This semi-automated new method has been easily implemented, reproducible, and therefore, could be useful tool for the bone CMI computation.

Absorptiometry, Photon↗

The application of indirect reduction techniques in the distal radius: the role of adjuvant arthroscopy.

PURPOSE: The re-establishment of distal radius alignment and articular congruency after fracture has been approached by a variety of methods in order to limit injury sequelae such as degenerative osteoarthritis. Although arthroscopy has been beneficial for other articular fractures, it is unclear to what degree arthroscopy should be used for treatment of distal radius articular fractures, especially when avoiding full-open procedures that can promote arthrofibrosis. The purpose of this study was to determine the utility of adjuvant wrist arthroscopy and whether a diagnostic benefit is observed during treatment. TYPE OF STUDY: A modified protocol for treatment of intra-articular distal radius fractures was developed in a crossover trial fashion for the purposes of this study. MATERIALS AND METHODS: Thirty-three consecutive subjects treated over a 2-year period were included for study. Fractures were classified according to Melone, treated by indirect reduction techniques under fluoroscopic visualization, stabilized by static external fixation, and supplemented with percutaneous pins or bone graft as needed. The adequacy of reduction under fluoroscopic visualization was assessed by arthroscopic visualization after this initial treatment. RESULTS: 14.3% of type I fractures, 37.5% of type II fractures, 33.3% of type III fractures, and 71.4% of type IV fractures were modified due to arthroscopic visualization after initial treatment by indirect reduction techniques. No subject required a full-open procedure for subsequent reduction. CONCLUSIONS: Based on these data, surgical treatment of intra-articular distal radius fractures solely under fluoroscopic visualization appears inadequate to re-establish articular congruency. Adjuvant wrist arthroscopy provides a diagnostic benefit in determining whether distal radius articular fracture reduction is adequate and may also translate to direct improvement in patient satisfaction and outcome by limiting injury sequelae. When considering indirect reduction techniques for distal radius articular injury, we recommend routine arthroscopic evaluation to verify and assist in re-establishment of articular congruency.

Adult↗

Vibration analysis of the human radius of elderly men.

UNLABELLED: Vibration analysis seldom has been used in detecting structural and mechanical changes in physiologic and pathologic bone conditions. We sought to correlate natural frequency of the radius measured by vibration analyses with bone mineral density measured by dual-energy xray absorptiometry and quantitative computed tomography (including cortical thickness). Sixty sedentary men between 50 and 70 years old were deemed osteopenic or healthy. A higher natural frequency of the dominant and nondominant radius was seen in the healthy men compared with the osteopenic men. Natural frequency was consistent with bone mineral density in dominant and nondominant radius in both groups. Moreover, there was a correlation between bone mineral density measured by dual-energy xray absorptiometry and natural frequency in the dominant and nondominant radius. Cortical thickness of the dominant and nondominant radius also correlated with natural frequency. We concluded natural frequency measured by vibration analysis is a precise method for the assessment of structural properties of bone and correlates with the bone mineral density of the radius. LEVEL OF EVIDENCE: Diagnostic study, Level II (Testing of previously developed diagnostic criteria on consecutive patients [with universally applied reference "gold" standard]). See the Guidelines for Authors for a complete description of the levels of evidence.

Absorptiometry, Photon↗

Comparison of different radiography systems in an experimental study for detection of forearm fractures and evaluation of the Müller-AO and Frykman classification for distal radius fractures.

OBJECTIVES: We sought to compare the diagnostic performance of screen-film radiography, storage-phosphor radiography, and a flat-panel detector system in detecting forearm fractures and to classify distal radius fractures according to the Müller-AO and Frykman classifications compared with the true extent, depicted by anatomic preparation. MATERIALS AND METHODS: A total of 71 cadaver arms were fractured in a material testing machine creating different fractures of the radius and ulna as well as of the carpal bones. Radiographs of the complete forearm were evaluated by 3 radiologists, and anatomic preparation was used as standard of reference in a receiver operating curve analysis. RESULTS: The highest diagnostic performance was obtained for the detection of distal radius fractures with area under the receiver operating curve (AUC) values of 0.959 for screen-film radiography, 0.966 for storage-phosphor radiography, and 0.971 for the flat-panel detector system (P > 0.05). Exact classification was slightly better for the Frykman (kappa values of 0.457-0.478) compared with the Müller-AO classification (kappa values of 0.404-0.447), but agreement can be considered as moderate for both classifications. CONCLUSIONS: The 3 imaging systems showed a comparable diagnostic performance in detecting forearm fractures. A high diagnostic performance was demonstrated for distal radius fractures and conventional radiography can be routinely performed for fracture detection. However, compared with anatomic preparation, depiction of the true extent of distal radius fractures was limited and the severity of distal radius fractures tends to be underestimated.

Area Under Curve↗