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Biomedical subjects

Z Aharonson

Publications and source records attributed to Z Aharonson.

15 recordsLinked to original sources

Foot-ground pressure pattern of flexible flatfoot in children, with and without correction of calcaneovalgus.

The footprint-measuring instrument was used to establish foot-ground pressure pattern of flexible flatfeet in male and female children, aged four to six years. Standing at ease, the children exerted most of their ground pressure by the posterior weight-bearing area (WBA). The rest was distributed between the middle and anterior WBAs, with the middle area usually exerting about 17%, and in extreme cases, as much as 30% of the total foot-ground pressure. Correcting valgus inclination of the calcaneus into neutral by inserting a leather wedge under the medial portion of the heel restored the longitudinal arch and the normal distribution of the foot-ground pressure of the standing child. The middle WBA exerted only 6% of the total pressure. This measuring system can differentiate between a normal foot, a flexible flatfoot, and a rigid flatfoot. It also can measure the exact amount of abnormal pressure being exerted by the middle WBA.

Biometry

The effect of pretraining sports activity on the incidence of stress fractures among military recruits. A prospective study.

In a prospective study of stress fractures among Israeli infantry recruits, no correlation was found between the recruits' prior participation in sports activities or their aerobic physical fitness and the incidence of stress fractures during basic training. This finding discredits the concept that improving physical fitness prior to basic training can be a prophylactic means of limiting the incidence of stress fractures during subsequent training.

Adult

Stress fractures and tibial bone width. A risk factor.

A prospective study of 295 infantry recruits has shown that the mediolateral width of the tibia measured radiographically at each of three different levels in the bone had a statistically significant correlation with the total incidence of stress fractures as well as with those in the tibia alone or the femur alone. A narrow tibial width was shown to be a risk factor, but cortical thickness was not found to be significant.

Femoral Fractures

External rotation of the hip. A predictor of risk for stress fractures.

External rotation of the hip was found to have a statistically significant correlation with the incidence of stress fractures, in a prospective study among Israeli infantry recruits of possible anthropomorphic predictors of risk for stress fractures. Soldiers in whom hip external rotation was greater than 65 degrees were at a higher risk for tibial and total stress fractures than those with external rotations of less than 65 degrees. The mean hip external rotation in this study of 57 degrees +/- 9.3 degrees was higher than in statistics reported in the American literature. The existence of a larger subpopulation with hip external rotation greater than 65 degrees may partially explain why the reported incidence of stress fractures in the Israeli army is higher than that of the American army.

Adolescent

Medial tibial pain. A prospective study of its cause among military recruits.

In a prospective study of 295 infantry recruits during 14 weeks of basic training, 41% had medial tibial pain. Routine scintigraphic evaluation in cases of medial tibial bone pain showed that 63% had abnormalities. A stress fracture was found in 46%. Only two patients had periostitis. None had ischemic medial compartment syndrome. Physical examination could not differentiate between cases with medial tibial bone pain secondary to stress fractures and those with scintigraphically normal tibias. When both pain and swelling were localized in the middle one-third of the tibia, the lesion most likely proved to be a stress fracture.

Fractures, Bone

A prospective study of the effect of a shock-absorbing orthotic device on the incidence of stress fractures in military recruits.

In a prospective study of stress fractures the hypothesis that a shock-absorbing orthotic device worn within military boots could lessen the incidence of stress fractures was tested. The incidence of metatarsal, tibial, and femoral stress fractures was lower in the orthotic group, but only the latter difference was statistically significant. The time of onset and the location of stress fractures between orthotic and nonorthotic users did not differ. These findings suggest that the incidence of femoral stress fractures, which are the most dangerous type of stress fracture because of their high risk of developing into displaced fractures, can be reduced by an orthotic device.

Fractures, Bone

The normal range of subtalar inversion and eversion in young males as measured by three different techniques.

In a prospective study, 272 males aged 18 to 20 had goniometric measurement of their subtalar inversion and eversion by three different methods. Placing the ankle in dorsiflexion while performing the measurements decreased the mean inversion from 32 to 22 degrees but had little effect on eversion. The neutral position of the subtalar joint was found to have a mean value of 3 degrees of varus from the midpoint of the tibia. The technique for measuring subtalar motion as described by the Committee for the Study of Joint Motion of the American Academy of Orthopaedic Surgeons has less subjective variables than the other two methods used in this study. Its use is therefore recommended if comparisons are to be made between series.

Adolescent

Stress fractures in military recruits. A prospective study showing an unusually high incidence.

In a prospective study of 295 male Israeli military recruits a 31% incidence of stress fractures was found. Eighty per cent of the fractures were in the tibial or femoral shaft, while only 8% occurred in the tarsus and metatarsus. Sixty-nine per cent of the femoral stress fractures were asymptomatic, but only 8% of those in the tibia. Even asymptomatic stress fractures do, however, need to be treated. Possible explanations for the unusually high incidence of stress fractures in this study are discussed.

Adolescent

Intraoperative nerve fascicle identification using choline acetyltransferase: a preliminary report.

One reason for failure of nerve recovery after suture or nerve grafting is the inappropriate matching of motor and sensory fibers. Methods used in attempting to solve this problem have either been unprecise, too time consuming, or unpleasant to the patient. Both experimentally and on cadaver samples, the level of choline acetylase activity is eight times higher in motor nerve fascicles than in sensory fascicles. In experimentally cut nerves, the ChAC activity remained high even after a period of 45 days. Thus it was possible to identify both ends of the motor and sensory fascicles in fresh injuries, and the proximal parts in old injuries. We have since used this method of intraoperative nerve identification in three patients. It has proved to be a rapid (70-80 minutes), viable technique for the immediate differentiation between proximal parts of motor and sensory nerve fascicles in cases of old nerve injuries. In contrast to our animal studies we found that the ChAC activity in the distal segment was still different for the various fascicles five months after transection. Presumably the present need for distal exploration to identify the "target organ" can be avoided.

Adult

Normal foot--ground pressure pattern in children.

A modern measuring aid for recording foot--ground pressure (FGP) distribution was used to establish normal patterns in male and female children aged 4 to 6 years. Computer analysis demonstrated the pressure exerted by each part of the foot. Standing at ease, the child with a normal foot exerts most of his ground pressure by the posterior weight-bearing area (WBA). The rest is distributed between the middle and anterior WBAs, with the middle portion exerting no more than 10% of the total foot--ground pressure. The advantage of this measuring system is that once a normal FGP has been established, it can serve as an important diagnostic aid and an accurate guide for deciding on appropriate conservative or surgical treatment of the feet of young children.

Child