Fractures of the clavicle are relatively common, occurring mostly in younger patients and have historically been managed non-operatively. Recent studies have shown an advantage to surgical reduction and stabilisation of clavicle fractures with significant displacement. Currently, fracture displacement is measured using simple anterior-posterior two-dimensional x-rays of the clavicle. Since displacement can occur in all three-dimensions, however, evaluation of the amount displacement can be difficult and inaccurate. The purpose of this study was to determine the view that provides the most accurate assessment.

Nine CT scans of acute displaced clavicle fractures were analysed with AmiraDEV5.2.2 Imaging software. Measurements for degrees of shortening and fracture displacement of the fracture clavicle were taken. Using a segmentation and manipulation module (ITK toolkit), five digitally reconstructed radiographs (DRRs) mimicking antero-posterior x-rays were created for every CT, with each differing by projection angle (ranging from 20° upwards tilt to 20° downwards tilt). Measurements were taken on each DRR using landmarks of entire clavicle length, distance from vertebrae to fracture (medial fragment length), distance from fracture to acromium (lateral fragment length), and horizontal shortening, and then compared to the true measurement obtained from the original CT.

For all 9 samples, after comparing the measurements of clavicle fracture displacement in each 2D image, we found that an AP view with a 20° downward tilt yielded displacement measurements closest to the 3D (“gold standard”) measurements. The results agree with previous data collected from cadaveric specimens using physical X-ray film images. DDRs enable creation of multiple standard AP radiographs from which accurate tilt can be measured. The large deviation in measurements on different DRR projections motivates consideration of standardising X-ray projections. A uniform procedure would allow one to correctly evaluate the displacement of clavicular fractures if fracture displacement information is to be utilized in motivating surgical decision-making.

Radiofrequency (RF) ablation carries success rate of 70–90% in the treatment of Osteoid Osteoma (OO). Failures are related to incomplete ablation which might be caused by the probe’s small heating radius (0.5–0.8 cm). Water cooled tips were developed in order to prevent charring of the tip and adjacent tissues and to allow for a larger, up to 3cm ablation diameter. To our knowledge safety and efficiency of this probe in the treatment of pediatric OO were never reported. Our goal was to examine if this technique, when added to conventional RF ablation, improves the clinical results and whether it carries any additional risks in the pediatric population.

Twenty two OO patients, 15 males and 7 females, 3 years and 6 months to 18 years old, were treated using the Cool-tip™ Tyco probe in a cooled mode followed immediately by conventional RF cycle under general anesthesia, in the CT suite. Fifteen of the lesions were in the femur, 2 in the tibia and the remainder lesions were located in the humerus, talus, calcaneus, 2nd metatarsus and sacrum. The OO was intraarticular in 5 patients: femur (3), calcaneus and Talus. Follow-up period averaged 38.5 months (range 16–66 months). All patients but one had their symptoms resolved immediately following a single treatment (95.5% success rate). One patient had partial relief and underwent second successful ablation. There were one recurrence after 18 months and one superficial infection. No fractures, neurovascular complications or growth disturbances were encountered.

We conclude that the addition of a Cool-tip cycle to conventional RF ablation in children is safe, efficient and reduces the risk of recurrence without adverse effects specific to this age group. We attribute this success to the larger diameter of heat distribution occurring due to cooling of the tip and the prevention of probe and tissue charring.

Introduction: Preliminary data suggest that immobilization in external rotation may be effective in lowering the incidence of recurrence after first traumatic shoulder dislocation, with a zero reoccurrence rate reported at 15 months follow-up. The purpose of the present study was to ascertain whether this method could lower the incidence of recurrent dislocation in a young, very physically active population.

Methods: In an IRB approved prospective study, young males who sustained first traumatic shoulder dislocation were randomized to be treated for four weeks either using a traditional internal rotation brace or a new device which immobilizes the shoulder at 15 to 20 degrees of external rotation. Subjects were then treated according to a standard physical therapy protocol. Follow-up was done at five time points in the first year post dislocation. Subjects with clinically stable shoulders resumed full activity after three months. Differences in outcome were assessed by the chi square test.

Results: Thirty nine subjects participated in the study. Thirty of them were soldiers. Twenty four subjects were treated with external rotation braces. At follow-up of between 4 to 28 months, a new dislocation was documented in 8 of the 24 subjects immobilized in external rotation (33%) and in 5 of the 15 subjects immobilized in internal rotation (33 %). No statistical difference (p=1.0) was found between the instability rates of the two treatment groups.

Discussion: The present study indicates that even in a short-term follow-up the technique of immobilizing a first dislocation in external rotation was not effective in lowering the incidence of recurrent shoulder dislocations in a young, physically active population.

Introduction: Several factors render plain X-ray radiographs of the hip unsuitable for bone mineral density measurements, mainly variability in X-ray exposure levels and soft tissue surrounding the bone. We present modification of proximal femur digital radiographs to compensate for these interfering factors.

Methods: The study population consisted of 99 women, in three groups: 1 – elderly, sustaining a fracture of the neck of the femur. 2 – elderly, without a fracture. 3 – young. Each patient’s hip was radiographed with a brass step-wedge for standard reference. Dual-Energy X-ray Absorptiometry (DEXA) of the same hip was performed. On each radiograph, Regions Of Interest (ROIs) of the proximal femur were determined in concordance with ROI of the DEXA, together with three soft tissue regions surrounding the bone. Mean gray level was measured for each ROI.

Results: The difference in gray level of the ROI within the proximal femur was not statistically significant between the groups. Correction of bone gray level to exposure level by dividing the gray level of the ROI to that of the step wedge, resulted in statistically significant difference between group 1 and either group 2 or group 3. Similar results were obtained by correction of bone gray level to soft tissue gray level. Using this method, multiple R² of 0.62 was found predicting the DEXA value from the gray level of each ROI.

Conclusions: After correction to the exposure level and to the soft tissue surrounding the bone, a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur. These preliminary results warrant further research aimed at exploring the potential value of this fast, accessible and relatively inexpensive technique to diagnose osteoporosis and the prediction of future fractures.

Introduction: The most widely accepted method for measuring bone mineral density (BMD) is Dual-energy X-ray Absorptionmetry (DXA). However, the need for relatively expensive equipment and trained personnel lower the accessibility of DXA as a routine screening tool. Plain pelvic X-ray radiography is a simple and inexpensive examination. In principal, the gray level of the bone in the X-ray radiograph is related to BMD. However, several factors render plain X-ray radiographs of the hip unsuitable for BMD measurements, mainly the variability in X-ray exposure levels and the soft tissue surrounding the bone. In this study, we aimed to develop new modifications of plain X-ray radiography of the proximal femur.

Patients and methods: The study population consisted of 18 women with an average age of 77 years (range 57–96 years) who were hospitalized due to a low-energy fracture of the neck of the femur. Each patient’s contralateral hip was radiographed with an aluminium step-wedge positioned near the hip as a standard reference, using a computerized radiography system. A DXA examination of the same hip followed the plain radiograph. On each radiograph, regions of interest (ROI) were determined in concordance with the ROI of the DXA examination. The mean gray level was measured for each ROI. The neck-shaft angle and the femoral head diameter were also measured.

Results: Comparing the gray levels of the plain radiograph with the BMD levels obtained by the DXA revealed a coefficient ratio of R=0.499. Correction of the gray levels using the step wedge as a standard reference revealed a ratio of R=0.576. If further correction was made with measurement of the soft tissue gray levels, a ratio of R=0.708 was obtained. Using the anatomical measurements (neck-shaft angle and femoral head diameter), a ratio of R=0.948 was obtained.

Conclusion: This study shows that a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur, which is comparable to the results of the DXA examination. Ultimately, the research can lead to the development of a fast, available and relatively inexpensive technique to diagnose osteoporosis.

Background: Time dependent, quantitative studies of muscle atrophy or passive muscle mechanics following chronic muscle detachment have not been previously reported. We developed a chronic tear of the rotator cuff tendon in a canine model to investigate and quantify the time related changes in the passive mechanics, volume, and fat of the infraspinatus muscle. We hypothesize that infraspinatus muscle stiffness will increase, volume will decrease, and fat content will increase at 12-weeks following tendon detachment.

Methods: The right infraspinatus tendons of eight adult mongrel dogs were surgically detached from the proximal humerus. The non-operated left shoulder served as a control. Muscle volume changes were quantified using MRI scans. At 12 weeks the passive mechanical properties of the chronically detached and control muscles were determined intraoperatively using a custom device. Intramuscular fat was evaluated histologically at sacrifice.

Results: After 12 weeks of detachment, the stiffness and modulus were significantly increased in the detached infraspinatus muscles relative to controls. MRI analysis demonstrated that the detached muscle volumes decreased by 33 percent in the first 6 weeks and remained constant thereafter. Intramuscular fat increased significantly in the detached muscles, and to a greater extent in the lateral regions.

Conclusions: The chronically detached muscle is not merely a smaller version of the original muscle but rather a “different” muscle. The detached muscle becomes stiffer and the passive loads required to repair it can become excessive. A significant reduction in muscle volume occurs within days to weeks following tendon detachment. The non-uniformity of muscle fat changes suggests that fat content should be used cautiously as an indicator of muscle quality.

Clinical Relevance: Clinically, chronic, large rotator cuff tendon tears are observed to have a qualitatively shorter and stiffer muscle-tendon unit than normal. We have developed a chronic rotator cuff model to quantitatively investigate changes in the detached infraspinatus muscle. The passive mechanical properties of a chronically torn rotator cuff muscle-tendon unit may be a useful predictor of reparability and clinical outcome.

Introduction: Bone strength is determined by several factors including bone mineral density and the geometrical structure of bone tissue. Plain X-ray is not used regularly for bone mineral density measurements due to different x-ray exposure used for each patient. The different radiation energies have major effects on the optical density of the obtained films. Therefore dual energy X-ray absorptiometry (DEXA) is the golden standard for bone density estimation. However it is relatively expensive and relatively inaccessible.

Objective: To evaluate a new computerized analysis of digitized plain radiographs of the proximal femur to allow the evaluation of bone mineral density in human subjects.

Material and Methods: 14 people hospitalized for proximal femoral fracture had their uninvolved proximal femur BMD estimated with a DEXA in the 5 typical regions defined by the DEXA test. Plain proximal femur radiographs of these patients were taken with a standard wedge and digitized into the computer to generate a digital image. The gray levels in the digital image were analyzed and normalized to yield the mineral content at the 5 regions defined by DEXA. The data obtained were correlated with the DEXA results.

Results: The correlation between BMD (DEXA) and gray level measurement of the proximal femur (R=0.261) was not significant. This correlation was significantly improved after modification of the gray levels to 0.549 (P< 0.032).

Conclusion: This computerized analysis and modification of gray levels in digitized radiographs improved significantly the possibility to evaluate bone mineral density of the proximal femur from plain X-rays.