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Biomedical subjects

M Nyska

Publications and source records attributed to M Nyska.

At least 37 records · Page 2Linked to original sources
PubMed2001

The contribution of the medial calcaneal osteotomy to the correction of flatfoot deformities.

HYPOTHESES/PURPOSE: The success of the medial displacement calcaneal osteotomy in correcting flatfoot deformities is likely to be the result of a shift of the Achilles tendon forces on the hindfoot. The purpose of this study was twofold: 1) to define the contribution of the Achilles tendon to the flatfoot deformity, and 2) to define the effect of a calcaneal medial displacement osteotomy. METHODS: We used six different experimental dynamic stages: 1) intact foot without Achilles loading; 2) intact foot with Achilles loading; 3) flatfoot without medial calcaneal displacement osteotomy and without Achilles loading; 4) flatfoot without medial calcaneal displacement osteotomy but with Achilles loading; 5) flatfoot with medial calcaneal displacement osteotomy but without Achilles loading; and 6) flatfoot with medial calcaneal displacement osteotomy and with Achilles loading. The experimental flaffoot was developed by releasing the posterior tibial tendon, spring ligament, and plantar fascia and applying 7,000 cycles of axial fatigue load (range, 700 to 1,400 N; 1-Hz frequency). To simulate the phase of midstance, the peroneus longus, peroneus brevis, flexor digitorum longus, and flexor hallucis longus tendons were grasped by clamps, connected to pneumatic actuators, and loaded with precalculated forces. Anteroposterior and lateral radiographs were obtained for each stage on which the following measurements were made: talonavicular coverage angle, talar-first metatarsal angle, talocalcaneal angle, and height of the medial cuneiform. These measurements were compared with a one-way ANOVA. RESULTS: Between stages 1 and 2, all measurements were statistically insignificant. Between stages 3 and 4, for all measurements, Achilles tendon loading aggravated the flatfoot deformity (p < 0.05). After medial calcaneal osteotomy (stages 5 and 6), the Achilles tendon contributed less to the arch-flattening. We found that the medial displacement osteotomy plays an important role in reducing and/or delaying the progress of flatfoot deformity. CONCLUSIONS/SIGNIFICANCE: In the flatfoot, loading of the Achilles tendon increases the deformity. Medial calcaneal osteotomy significantly decreases the arch-flattening effect of this tendon and therefore limits the potential increase of the deformity.

Achilles Tendon↗
PubMed2001

The effect of shoe sole composition on in vivo tibial strains during walking.

To test the hypothesis that shoe sole composition can affect the level of bone strain and strain rates that contribute to the development of stress fractures, in vivo tibial strain measurements were made during treadmill walking while wearing four shoes which differed only in their sole composition. Soles of 65 Shore A polyurethane with an embedded heel air cell had significantly lower compression and shear strains and shear strain rates than soles of 65, 75 and a composite of 40/65 Shore A polyurethane with no embedded air cells. A sole composed of 65 Shore A polyurethane with an embedded air cell can potentially be protective against stress fracture in a walking shoe.

Adult↗
PubMed2001

Fractures of the lateral process of the talus in children.

Fractures of the lateral process of the talus are an uncommon injury, which are often misdiagnosed as severe ankle sprain. This error may result in inappropriate treatment of an intraarticular fracture, with subsequent posttraumatic arthrosis. To date, only one fracture of a lateral talar process has been reported in a child, in whom delayed diagnosis and initial mismanagement led to a suboptimal result. The sport of 'snowboarding', which is gaining in popularity, has been significantly associated with fractures of the lateral talar process, leading some authors to dub this fracture 'Snowboarder's Fracture'. This and the ever-increasing incidence of major trauma lead us to believe that this fracture will be encountered more frequently, even in the pediatric population, as the two factors mentioned do not pass over this group. We report lateral talar process fractures in two children: one in a 9-year-old girl and one in an 11-year-old boy, the latter associated with talar neck and body fractures. Timely diagnosis enabled prompt open reduction and internal fixation, preventing subtalar arthrosis. We discuss the pertinent anatomy and mechanism, and present the clinical picture, imaging studies and treatment. Two important points are exemplified by these cases. First, this fracture, although rare, does occur in children, and should be sought in appropriate settings. Second, despite the severe talar injury in the 11 year old, early diagnosis and intervention conserved foot function.

Ankle Injuries↗
PubMed2001

Continuous intra-articular patient-controlled analgesia in a cancer patient with a pathological hip fracture. A case report.

Pain management is one of the major goals to achieve in treating terminal patients. Managing severe pain with drug therapy by using a combination of narcotics, non-narcotics, and adjuvant drugs provides the best results for most patients. In patients with fractures due to bone metastases there is a relative indication for operative treatment if the patient is expected to survive the operation and to recover in the postoperative period. In this case report a terminal 48 year-old female with a pathological femoral neck fracture is presented. No operative treatment was offered because of her bad general status. Pain control was maintained by continuous administration of local analgesics directly into the intra-articular femoral space, through a system of patient-controlled analgesia (PCA). The visual-analogue pain scale (VAS), which was maximal before beginning of this treatment, was markedly reduced during the treatment, and was again elevated to maximum after the intra-articular catheter was removed. Although continuous regional analgesia to a fractured bone which involves the joint is not a generally acceptable method and carries some risks it has a role in a selected group of patients.

Analgesia, Patient-Controlled↗
PubMed2000

Spondylolysis as a cause of low back pain in swimmers.

Low back pain (LBP) has recently become a common complaint in swimmers. The differential diagnosis of LBP in swimmers includes muscle and ligament sprains, Scheuerman disease, herniated disc, facet joint injury, tumors, infections, and spondylolysis. Although spondylolysis or listhesis is a frequent injury in the athlete, mainly in weightlifters, wrestlers, gymnasts, divers and ballet dancers, it is infrequently reported in swimmers. We have recently encountered four adolescent elite swimmers who complained of low back pain and were diagnosed as having spondylolysis. Three of the patients were either breast-strokers or butterfly swimmers. Plain radiography demonstrated the lesion in two patients. Increased uptake in bone scan was noted in all patients. CT was performed only in two patients and revealed the lesion in both. One patient was diagnosed within two weeks, and the diagnosis in the others was deferred for 2-7 months. The patients were treated successfully by reducing the intensity of their training program and the use of a corset for at least three months. Repeated hyperextension is one of the mechanisms for spondylolysis in athletes as is the case in breast-strokers and butterfly style swimmers. LBP in swimmers should raise the suspicion of spondylolysis. Plain radiography and bone scan should be performed followed by SPEC views, CT, or MRI as indicated. If the case is of acute onset as verified by bone scan, a Boston or similar brace should be used for 3 to 6 months in conjunction with activity modification and optional physical therapy. Multidisciplinary awareness of low back pain in swimmers, which includes trainers, sport medicine physicians, and physical therapists, should lead to early diagnosis and appropriate treatment.

Adolescent↗
PubMed2000

Do high impact exercises produce higher tibial strains than running?

BACKGROUND: Bone must have sufficient strength to withstand both instantaneous forces and lower repetitive forces. Repetitive loading, especially when bone strain and/or strain rates are high, can create microdamage and result in stress fracture AIM: To measure in vivo strains and strain rates in human tibia during high impact and moderate impact exercises. METHODS: Three strain gauged bone staples were mounted percutaneously in a rosette pattern in the mid diaphysis of the medial tibia in six normal subjects, and in vivo tibial strains were measured during running at 17 km/h and drop jumping from heights of 26, 39, and 52 cm. RESULTS: Complete data for all three drop jumps were obtained for four of the six subjects. No statistically significant differences were found in compression, tension, or shear strains with increasing drop jump height, but, at the 52 cm height, shear strain rate was reduced by one third (p = 0.03). No relation was found between peak compression strain and calculated drop jump energy, indicating that subjects were able to dissipate part of the potential energy of successively higher drop jumps by increasing the range of motion of their knee and ankle joints and not transmitting the energy to their tibia. No statistically significant differences were found between the principal strains during running and drop jumping from 52 cm, but compression (p = 0.01) and tension (p = 0.004) strain rates were significantly higher during running. CONCLUSIONS: High impact exercises, as represented by drop jumping in this experiment, do not cause higher tibial strains and strain rates than running and therefore are unlikely to place an athlete who is accustomed to fast running at higher risk for bone fatigue.

Adult↗
PubMed2000

In-vivo strain measurements to evaluate the strengthening potential of exercises on the tibial bone.

Mechanical loading during physical activity produces strains within bones. It is thought that these forces provide the stimulus for the adaptation of bone. Tibial strains and rates of strain were measured in vivo in six subjects during running, stationary bicycling, leg presses and stepping and were compared with those of walking, an activity which has been found to have only a minimal effect on bone mass. Running had a statistically significant higher principal tension, compression and shear strain and strain rates than walking. Stationary bicycling had significantly lower tension and shear strains than walking. If bone strains and/or strain rates higher than walking are needed for tibial bone strengthening, then running is an effective strengthening exercise for tibial bone.

Adult↗
PubMed1998

Fracture of the posterior body of the talus--the hidden fracture.

Fractures of the entire posterior process of the talus are rare and may be easily missed. Both the ankle joint and the subtalar joint are involved. This leads to malunion and early degenerative changes. We describe four patients with fractures of the posterior process of the talus which were initially missed. The patients were treated conservatively, and early mobilization or cast immobilization did not change the poor late results. The pitfalls in the diagnosis and imaging evaluation of such fractures are discussed.

Adult↗
PubMed1998

Traumatic myositis ossificans of the quadriceps in infants.

Acute traumatic myositis ossifications is uncommon and usually occurs in adolescents and young adults after a significant direct blow to the affected muscle. It is extremely rare in infants, and we have been able to find only two other cases in the English literature. We present two cases of traumatic myositis ossificans in infants who, except for the use of diagnostic ultrasonography, would have been misdiagnosed as having osteomyelitis (Patient 1) and a possible malignancy (Patient 2).

Acute Disease↗
PubMed1998

'Epiphyseal dysgenesis' in Laurence-Moon-Biedl-Bardet syndrome.

Ten patients with Laurence-Moon-Biedl-Bardet syndrome were investigated. They all belonged to one large family within which several intermarriages had taken place. We found that, apart from the already described abnormalities, these patients suffered from dysgenesis of the following epiphyses: vertebrae, proximal femur, proximal tibia, capitellum, tarsal navicular, and the distal epiphysis of the first metatarsal. The degree of polydactyly, a prominent feature of this syndrome, varied from patient to patient, ranging from a wide fifth metatarsal or metacarpal to a complete sixth digit. As in other epiphyseal dysgenesis, a pseudoepiphysis of the distal first metacarpal was present. One patient (the eldest) was tetraparetic due to severe spinal stenosis.

Adolescent↗
PubMed1998

A comparison of the effect of shoes on human tibial axial strains recorded during dynamic loading.

Percutaneous axial extensometers were mounted on the medial cortex of the midtibial diaphysis in seven male volunteers and the effect of three different shoes on in vivo peak-to-peak axial compression-tension strains measured during dynamic loading. Zohar shoes had lower axial strains and strain rates during treadmill walking than Nike Air Max running shoes or Israeli infantry boots. During running on a running track, there was no statistically significant difference between the axial strains or strain rates between the shoes tested. Shoe gear can modify tibial strains and strain rates that contribute to the development of tibial stress fractures.

Adult↗
PubMed1997

The adaptation of the foot to heavy loads: plantar foot pressures study.

INTRODUCTION:: The foot serves as the main shock absorber during various activities as walking running and jumping. There are static and dynamic mechanisms which play a role in the adaptation of the foot to weight bearing walking with weights. The function of the foot while weight bearing was studied mainly under static conditions. We designed an experiment to explore dynamically the adaptation of the foot to weight bearing walking with weights. METHODS:: Ten healthy subjects participated the study. They walked barefoot over an EMED force plate which based on multiple pressure capacitance sensors. Each subject walked three times. The first walk was without any weight, the second walk with weight of 20 kg in backpack and the third walk with weight of 40 kg. Contact area, peak pressures, peak forces and duration of contact time were measured in seven areas of interest of the foot-heel, midfoot, lateral, central and medial forefoot, lateral toes and hallux. RESULTS:: The pressure time integral and force time integral increased in most areas of the foot except for the midfoot in the 20 kg walk. The largest increase was at the central and medial forefoot. Adding additional 20 kg to the load did not increased the loads on the midfoot but increased further the loads mainly at the central and medial forefoot. CONCLUSIONS:: The human foot adapts itself under loading condition by maintaining the medial longitudinal arch. Increasing the loading further activates compensatory mechanisms which maintain the longitudinal arch and shifts the the loads to the central and medial forefoot.

Journal Article↗
PubMed1997

Floating metatarsal: concomitant Lisfranc fracture-dislocation and complex dislocation of the first metatarsophalangeal joint.

We describe a unique composite injury of the foot, with concomitant Lisfranc fracture-dislocation, and complex dislocation of the first metatarsophalangeal joint. When examining patients with Lisfranc joint injuries, one must keep in mind that the axial compression forces causing the injury may also damage the metatarsophalangeal joints, and direct attention to these structures. The reduction and stabilization of a "floating" first metatarsal should begin at the distal (metatarsophalangeal) end. The reduction of the distal dislocation will release tension on the plantar fascia, enabling the subsequent reduction of the proximal (Lisfranc) dislocation. A medial approach is convenient, affords easy access to the plantar and dorsal aspects of the joint, and repair of the medial joint structures when damaged. The use of screws for fixation of Lisfranc's fracture-dislocation, is well justified by the stability achieved.

Adult↗
PubMed1997

Planter foot pressures in pregnant women.

UNLABELLED: The physiological changes occurring during pregnancy may be responsible for the faulty foot position leading to backache and lower limb pain. We evaluated the changes in the plantar foot pressures during pregnancy. Twenty-eight, full-term, healthy, pregnant women, average age 28 years, were examined and evaluated clinically, and the plantar foot pressure distribution was measured statically and dynamically using the EMED system. Twenty-eight, non-pregnant women, average age 25 years, served as the control group. In the static measurements, the pregnant women had significantly lower maximal forefoot pressures and higher hindfoot pressures than the non-pregnant women. The area of the foot in contact with the measuring pressure plate was greater in the pregnant women than in the non-pregnant women. In the dynamic measurements, the maximal force in almost every area of interest was significantly higher. The total force exerted on the pressure plate at the instant of maximal force of every area of interest during the whole step was higher in the pregnant group. On the medial side of the forefoot there was a slight decrease in the contact time of the maximal force. The peak pressures were higher in the midfoot of both feet and on the lateral side of the right forefoot in the pregnant women. In the medial side of the forefoot, the peak pressures were lower in pregnant women. CONCLUSIONS: The pregnant woman has a different pattern of gait. There is an increase of load on the lateral side of the foot and the hindfoot. These changes may be responsible for the musculoskeletal complaints of lower limb pain in pregnant women.

Adult↗