A new mechanical testing device for measuring anteroposterior knee laxity

BACKGROUND: The authors assessed a new instrument, the Rolimeter, for the measurement of anteroposterior translation in the knee; it was compared to the KT-1000 arthrometer. PURPOSE: To determine if the Rolimeter offers a valid method for the measurement of anteroposterior translation that is as reproducible and reliable as the KT-1000 arthrometer. METHODS: Two of 3 observers examined 16 normal subjects (32 knees) and 36 patients (72 knees) with ligament ruptures twice, using both the Rolimeter and the KT-1000 arthrometers, 30 minutes apart. Total anteroposterior translation (manual maximal Lachman test) was recorded at 20 degrees and 80 degrees of knee flexion. RESULTS: On average, the Rolimeter measured approximately 1 mm less anteroposterior displacement than the KT-1000 arthrometer at manual maximum stress. Rolimeter measurements were more consistent than the KT-1000 measurements as measured by our observers. Specificity and sensitivity were equivalent between the Rolimeter and the KT-1000 arthrometer. CONCLUSIONS: The Rolimeter is as reproducible and reliable as the KT-1000 arthrometer. It offers a valid method for the measurement of anteroposterior translation in the knee. Higher accuracy was obtained at 20 degrees of flexion for the KT-1000 arthrometer and at 80 degrees of flexion for the Rolimeter.     

A simple device for measuring anaerobic power

Having no funds to purchase sophisticated equipment to measure human anaerobic power, a simple cheaply made device was constructed based on the principle of the method introduced by Margaria et al (1966). This improvised apparatus consists of two contact pads each having a make and break provision of an electrical circuit with the help of leaf springs and can be used to measure human vertical velocity and anaerobic power. Details of the device are described and illustrated, and the results presented from a test of anaerobic power on 92 men and women athletes at national level in different sports. These results have been compared with the corresponding results available in the literature.     

A comparative study of simple bone cysts of the jaw and extracranial bones

OBJECTIVES: To improve the interpretation of simple bone cyst (SBC) lesions of the jaw. METHODS: A comparative study of SBC lesions of the jaw and extracranial bones was performed through a literature survey. RESULTS: In extracranial SBC, the cavities were always filled with fluid, and a high recurrence rate was shown through extensive research. Aneurysmal bone cyst (ABC) was included in the differential diagnosis owing to some clinicopathologic similarities. Fluid, gas and blood were found in the cavity in jawbone SBC, and recurrence was believed to be rare. Differential diagnosis was rarely discussed in the literature. CONCLUSIONS: Based on reports, the cavity did not normally contain gas because no air-fluid level was observed on panoramic radiographs and no density/intensity area indicating gas was seen on CT or MRI. A blood-filled cavity should be examined carefully, and the possibility of an ABC should be considered. The recurrence rate needs to be re-estimated because an extensive survey has not been performed to clarify the treatment outcomes of jawbone SBC.     

A simple device for measuring radon exhalation from the ground

A special device was developed for measuring radon exhalation from the ground in the earthquake prediction research. A solid state nuclear track (SSNT) detector (CA 80-15) has been used as a probe. The thoron registration is reduced by a factor of 10³. Several problems concerning field measurements (e.g. humidity) were solved.     

Cemento-osseous dysplasia of the jaw bones: key radiographic features

Objective

The purpose of this study is to assess possible diagnostic differences between general dentists (GPs) and oral and maxillofacial radiologists (RGs) in the identification of pathognomonic radiographic features of cemento-osseous dysplasia (COD) and its interpretation.

Methods

Using a systematic objective survey instrument, 3 RGs and 3 GPs reviewed 50 image sets of COD and similarly appearing entities (dense bone island, cementoblastoma, cemento-ossifying fibroma, fibrous dysplasia, complex odontoma and sclerosing osteitis). Participants were asked to identify the presence or absence of radiographic features and then to make an interpretation of the images.

Results

RGs identified a well-defined border (odds ratio (OR) 6.67, P < 0.05); radiolucent periphery (OR 8.28, P < 0.005); bilateral occurrence (OR 10.23, P < 0.01); mixed radiolucent/radiopaque internal structure (OR 10.53, P < 0.01); the absence of non-concentric bony expansion (OR 7.63, P < 0.05); and the association with anterior and posterior teeth (OR 4.43, P < 0.05) as key features of COD. Consequently, RGs were able to correctly interpret 79.3% of COD cases. In contrast, GPs identified the absence of root resorption (OR 4.52, P < 0.05) and the association with anterior and posterior teeth (OR 3.22, P = 0.005) as the only key features of COD and were able to correctly interpret 38.7% of COD cases.

Conclusions

There are statistically significant differences between RGs and GPs in the identification and interpretation of the radiographic features associated with COD (P < 0.001). We conclude that COD is radiographically discernable from other similarly appearing entities only if the characteristic radiographic features are correctly identified and then correctly interpreted.     

A new portable device for assessing locomotor performance

We investigated the validity of a new portable system and the feasibility of the method for gait analysis as the assessment of gait has clinical relevance in the study of locomotor pathologies. This system is composed of a data logger, triaxial accelerometers, and software. Measurements of the pelvis kinematics during gait were performed on five hip osteoarthritic subjects and 15 healthy subjects using the portable system and a reference system (Vicon). The healthy subjects were studied in conditions of normal gait and gait altered by a heelpiece. The studied variables were the vertical amplitude of the sacrum, the time of gait cycle and the vertical trajectories of the spines. The new system corresponded with the reference system for the studied variables. The small differences between the two systems in the vertical amplitude of the sacrum (0.53 +/- 6.39 mm), time of the gait cycle (0.002 +/- 0.05 s), and the vertical trajectories of the spine (coefficient correlation of 0.06 +/- 0.05) confirmed the validity of the portable system data. The results showed a distortion of the pelvis trajectory when the gait was impaired. The portable system provides an objective method to discriminate normal from limping gait and is easy to use outside of the laboratory.     

Investigation of proton density for measuring tissue temperature

PURPOSE: To examine the temperature dependence of the proton density (PD) in both adipose and muscle tissues, and the application of the PD as a thermometry parameter in breast tissues. MATERIALS AND METHODS: Porcine fat samples and bovine muscle samples were successively heated to temperatures ranging from 30 degrees C to 76 degrees C and then cooled. They were then imaged with a dual-echo spin-echo sequence. T1 and T2 effects were carefully corrected from the images. The apparent PD (APD) in regions of interest (ROIs) and the sum of the APD in all pixels (Sum_APD) were measured and analyzed by linear regression. RESULTS: APD in adipose tissue is linear and reversible, and changes with a 0.3%/ degrees C to 0.45%/ degrees C temperature variation. The temperature coefficient of Sum_APD in adipose tissue is approximately 0.29%/ degrees C, as predicted from the Boltzmann distribution. However, the results in muscle tissue are more variable. There is an offset in both APD and Sum_APD between heating and cooling phases, as well as different temperature coefficients between these two phases. CONCLUSION: The Sum_APD in adipose tissue validates the 1/T dependence on temperature. The APD is a potentially useful parameter for fat thermometry; however, its application in muscle tissue requires further investigation.