Low bone density is an etiologic factor for stress fractures in athletes

Insufficiency and stress fractures of the long bones occurring in patients with rheumatoid arthritis and other inflammatory diseases, with a contribution on the possibilities of computed tomography

In patients with long standing rheumatoid arthritis and other rheumatoid disorders, stress fractures and insufficiency fractures are not uncommon. The cause may be osteoporosis due to rheumatoid arthritis, corticosteroid therapy, joint stiffness, and deformity of the joints caused by the inflammatory process. Also, unaccustomed exercise after reconstructive joint surgery may be a cause of fractures in these patients. Fractures can be documented on conventional X-ray-pictures and tomograms. Computed tomography can show the medullary extent of these fractures and gives, in several cases, additional information showing the combination of insufficiency fractures with fragmentations of parts of the involved bone. Reconstructive surgery with total joint replacement may be another cause of the development of these fractures. This unaccustomed increase in ambulation may lead to stress fractures in other joints of the same extremity or of contralateral extremity. Pain beginning in joint of the lower extremity in a patient with chronic rheumatoid arthritis should, besides arthritis, raise the possibility of a stress fracture. Also with cases of angular deformity of a joint and unaccustomed exercise after reconstructive surgery patients stress fractures may be seen and can be established by Plainfilm, Computed Tomography scintimetric bone scanning and MRI.

The preparticipation sports examination for high school and college athletes

The PSE can be used as a tool to allow athletes to participate safely in sports. The goal of the PSE is not to disqualify athletes but to ensure that their participation in sports does not unnecessarily increase their risk of injury. The PSE is most effectively conducted by the station method with multiple examiners, one of whom should have specialty training in musculoskeletal disorders. The examination should be conducted 6 weeks prior to the beginning of the season and at the beginning of each new level of competition, unless directed differently by local laws. The correct use of the PSE should screen for signs and symptoms of pathological states that may lead to a nontraumatic death while participating in sports. An effective musculoskeletal examination should detect any postinjury deficits that may lead to subsequent reinjury later in the season. It is our hope that a PSE, based on the literature, can be used to prevent some of the nontraumatic deaths and musculoskeletal injury associated with sports participation.

Skeletal effects of menstrual disturbances in athletes

This article reviews the skeletal effects and clinical implications of menstrual disturbances in active women. At the lumbar spine, menstrual disturbances are associated with premature bone loss or failure to reach peak bone mass, while appendicular sites are less affected. This suggests that trabecular bone is more sensitive to hormonal stimuli and less responsive to mechanical loading than cortical bone. Although the mechanisms responsible for the detrimental effects of menstrual disturbances are likely to be multifactorial, low circulating levels of oestrogen are thought to be the main cause. The clinical significance of menstrual disturbances depends upon a number of factors, including type of sport, genetic background, body composition and calcium intake. Not all athletes who present with menstrual disturbances will develop osteopenia. Nevertheless, the risk of stress fracture does seem to be increased in athletes with menstrual disturbances and with lower bone density. Whether athletes with menstrual disturbances are at a greater risk for osteoporosis in later life is not yet known. Bone loss can be at least partially reversed, especially with the spontaneous resumption of menses. This may serve to offset any previous increased risk of osteoporosis. Furthermore, other factors, apart from low bone mass, act to determine the likelihood of osteoporotic fractures. Therefore, the clinical significance of menstrual disturbances associated with exercise participation needs to be established for each individual athlete. Bone densitometry may guide the clinician in this respect and assist in the formulation of appropriate management strategies.

American College of Sports Medicine position stand. The Female Athlete Triad

The Female Athlete Triad is a syndrome occurring in physically active girls and women. Its interrelated components are disordered eating, amenorrhea, and osteoporosis. Pressure placed on young women to achieve or maintain unrealistically low body weight underlies development of the Triad. Adolescents and women training in sports in which low body weight is emphasized for athletic activity or appearance are at greatest risk. Girls and women with one component of the Triad should be screened for the others. Alone or in combination, Female Athlete Triad disorders can decrease physical performance and cause morbidity and mortality. More research is needed on its causes, prevalence, treatment, and consequences. All individuals working with physically active girls and women should be educated about the Female Athlete Triad and develop plans to prevent, recognize, treat, and reduce its risks.

Stress injury to bone in the female athlete

Stress injury to bone exists on a continuum, involving mechanical as well as hormonal and nutritional factors. Risk factors for stress injury include genetics, female gender, white ethnicity, low body weight, lack of weightbearing exercise, intrinsic and extrinsic mechanical factors, amenorrhea, oligoamenorrhea, inadequate calcium and caloric intake, and disordered eating. Prevention of stress injury to bone involves maximizing peak bone mass in the pediatric, adolescent, and young adult age groups. Maintaining adequate calcium nutrition and caloric intake, exercise and hormonal balance are important preventive measures in the adult years for optimizing skeletal integrity and preventing fractures. There are no prospective longitudinal studies to date that demonstrate a treatment that will increase bone density in female athletes with hypothalamic hypoestrogenic amenorrhea or disordered eating that have low bone density. Advances in genetic research show promise for future preventive and treatment strategies. More research is needed in this area to determine other factors that may be contributing to bone loss in these individuals, as well as to assess other treatment options leading to improvements in bone density and integrity.

Stress fractures: general concepts

This article is an overview of the general concepts about stress fractures, including history, epidemiology, and cause. The proper diagnosis, confirmation studies, and treatment regimens are presented. Finally, the timing of the athlete's return to sports, with stress fracture prevention measures are reviewed.

Irreversible bone loss in former amenorrheic athletes

Small gains in bone mineral density (BMD) have been reported in the first year following resumption of menses in amenorrheic athletes but there have been no long-term outcome studies. The purpose of this study was to determine whether the BMD of former oligomenorrheic or amenorrheic athletes normalizes following several years of normal menses or use of oral contraceptives. Twenty-nine athletes first studied in this laboratory 8.1 years (range 6-10 years) ago were available for follow-up. At recruitment (time 1) 29 athletes, mean age of 30.6 years, were non-smokers, exercised 4 or more days/week for at least 45 min, had not used oral contraceptives, and had no medical conditions affecting bone metabolism. At time 1, 9 women (R/R) had always menstruated regularly, 9 (R/O/A) had experienced intermittent oligo/amenorrhea as well as regular menses, and 11 (O/A) had never menstruated regularly. At follow-up (time 2) mean age of the women was 38.2 years and there were no significant changes in height, weight or activity patterns. BMD (g/cm2) was measured at the lumbar vertebrae (L1-4 and femoral neck by dual-energy X-ray absorptiometry and expressed as a percentage of R/R values. Vertebral BMD was significantly lower in the O/A group compared with the R/R group at both time 1 and time 2 (p < 0.05). The R/O/A group had intermediate values and did not differ significantly from R/R or O/A at either time. Differences in technique between machines for determining femoral neck BMD made it difficult to detect the longitudinal effect of menstrual status at that site. Despite several years of normal menses or use of oral contraceptives, the mean vertebral BMD of former oligo-amenorrheic athletes remained low, being 84.4% of the R/R value compared to 84.8% at time 1. Those experiencing menstrual regularity with intermittent oligo/amenorrhea remained at an intermediate position of 94.7% of the R/R mean. Our results suggest early intervention is necessary to prevent irreversible vertebral bone loss in oligo/amenorrheic athletes.

Risk factors for stress fractures in track and field athletes. A twelve-month prospective study

The aim of this 12-month prospective study was to investigate risk factors for stress fractures in a cohort of 53 female and 58 male track and field athletes, aged 17 to 26 years. Total bone mineral content, regional bone density, and soft tissue composition were measured using dual-energy x-ray absorptiometry and anthropometric techniques. Menstrual characteristics, current dietary intake, and training were assessed using questionnaires. A clinical biomechanical assessment was performed by a physical therapist. The incidence of stress fractures during the study was 21.1% with most injuries located in the tibia. Of the risk factors evaluated, none was able to predict the occurrence of stress fractures in men. However, in female athletes, significant risk factors included lower bone density, a history of menstrual disturbance, less lean mass in the lower limb, a discrepancy in leg length, and a lower fat diet. Multiple logistic regression revealed that age of menarche and calf girth were the best independent predictors of stress fractures in women. This bivariate model correctly assigned 80% of the female athletes into their respective stress fracture or nonstress fracture groups. These results suggest that it may be possible to identify female athletes most at risk for this overuse bone injury.

The effect of weight-bearing exercise on bone mineral density: a study of female ex-elite athletes and the general population

The aim of this retrospective cohort study was to estimate the changes in bone mineral density (BMD) as a consequence of exercise in female ex-athletes and age-matched controls. Eighty-three ex-elite female athletes (67 middle and long distance runners, 16 tennis players, currently aged 40-65) were recruited from the original records of their sporting associations. Controls were 585 age-matched females. The main outcome measures were BMD of lumbar spine (LS), femoral neck (FN), and forearm, estimated by dual-energy X-ray absorptiometry (DXA) scan. Levels of physical activity were assessed using a modified Allied Dunbar Fitness Survey scale and classified as (a) ex-athletes, (b) active controls (> or = 1 h of vigorous physical activity currently and in the past), (c) low activity controls with inconsistent or intermediate levels of activity, and (d) inactive controls (< 15 minutes of exercise per week). After adjustment for differences in age, weight, height, and smoking, athletes had greater BMDs than controls: 8.7% at the LS (95% confidence interval [CI] 5.4-12.0; p < 0.001) and 12.1% at FN (CI 9.0-15.3; p < 0.001). The benefits of exercise appeared to persist after cessation of sporting activity. Active controls (n = 22) had greater BMDs than the inactive group (n = 347): 7.9% LS (CI 2.0-13.8; p = 0.009) and 8.3% FN (CI 2.7-13.8; p = 0.004). The low activity controls (n = 216) had an intermediate BMD. Tennis players had greater BMDs compared with runners: 12.0% LS (CI 5.7-18.2; p = 0.0004) and 6.5% FN (CI -0.2-13.2; p = 0.066). The BMD of tennis players' dominant forearms were greater than their nondominant forearms. In conclusion, regular vigorous weight-bearing exercise of 1 h or more per week is associated with an increase in BMD within a normal population. This study confirms long-term weight-bearing exercise as an important factor in the regulation of bone mass and fracture prevention.

Amenorrhea in ballet dancers in the Netherlands

The prevalence of amenorrhea was studied among 113 professional and student ballet dancers in the Netherlands (mean age 23.3 yr, SD 4.8). Sixty-one dancers not on oral contraceptives were included in the subsequent analyses. Six cases (prevalence 9.8 percent, 95 percent confidence interval: 2.4-17.2) with secondary amenorrhea (< or = 4 cycles per year; previous menstruation > or = 3 months prior to the study; menarche > or = 1 yr prior to the study) were found. Two dancers had primary amenorrhea (no menarche at the age of > or = 16). There was a negative correlation between the age of menarche and the number of menstrual cycles during the 12 months preceding the study (r = -0.46, P = 0.001). Body composition (four-compartment model), amount of dancing (recorded), resting energy expenditure (ventilated hood), dietary intake (recorded), and indices of eating disorders (Eating Disorders Inventory, EDI) were studied in 15 of the dancers, 5 amenorrheic and 10 eumenorrheic. No significant differences were found between the amenorrheic and eumenorrheic dancers. An explanation for the lower prevalence of amenorrhea in ballet dancers in the Netherlands, compared with U.S. dancers, was not obvious. Relatively low EDI scores (25.8, SD 14.5) in a subsample of 24 dancers could indicate less rigid emphasis on leanness and dieting.

Can adrenarche influence the degree of osteopenia in thalassemic children?

In order to evaluate whether changes of adrenal steroid serum levels occurring during the prepubertal period influence the degree of osteopenia, dehydroepiandrosterone sulfate (DHEAS) was longitudinally monitored as marker of the onset of adrenarche. Fifteen thalassemic patients, 9 girls (Group 1) and 6 boys (Group 2), with chronological age (CA) from 6.1 to 10.3 years and bone age (BA) from 6 to 9.6 years, were studied. Two observations, 14 months apart, were made. All patients had no pubertal signs according to Tanner during the period of observation, and auxological data (height, BMI and height velocity) were evaluated in respect to bone age. There was a statistically significant difference between the two groups for serum DHEAS, BGP serum levels, height velocity and bone mineral density expressed as standard deviation score (BMDsds) in respect to both bone age and height age (the latter was calculated in order to eliminate the influence of height on BMD). Alterations of bone metabolism were excluded by determination of calcium, phosphorus, alkaline phosphatase activity, parathormone, 25-OH-D3, IGF-I serum levels, all these values being normal. In conclusion, our data show that a delayed adrenarche occurs in thalassemic boys which is correlated with a severe degree of osteopenia, even though the relationship between them is not yet established.

The incidence and distribution of stress fractures in competitive track and field athletes. A twelve-month prospective study

The incidence and distribution of stress fractures were evaluated prospectively over 12 months in 53 female and 58 male competitive track and field athletes (age range, 17 to 26 years). Twenty athletes sustained 26 stress fractures for an overall incidence rate of 21.1%. The incidence was 0.70 for the number of stress fractures per 1000 hours of training. No differences were observed between male and female rates (P > 0.05). Twenty-six stress fractures composed 20% of the 130 musculoskeletal injuries sustained during the study. Although there was no difference in stress fracture incidence among athletes competing in different events (P > 0.05), sprints, hurdles, and jumps were associated with a significantly greater number of foot fractures; middle- and long-distance running were associated with a greater number of long bone and pelvic fractures (P < 0.05). Overall, the most common sites of bone injuries were the tibia with 12 injuries (46%), followed by the navicular with 4 injuries (15%), and the fibula with 3 injuries (12%). The high incidence of stress fractures in our study suggests that risk factors in track and field athletes should be identified.

Tibial stress reaction in runners. Correlation of clinical symptoms and scintigraphy with a new magnetic resonance imaging grading system

Medial tibial pain in runners has traditionally been diagnosed as either a shin splint syndrome or as a stress fracture. Our work using magnetic resonance imaging suggests that a progression of injury can be identified, starting with periosteal edema, then progressive marrow involvement, and ultimately frank cortical stress fracture. Fourteen runners, with a total of 18 symptomatic legs, were evaluated and, within 10 days, referred for radiographs, a technetium bone scan, and a magnetic resonance imaging scan. In 14 of the 18 symptomatic legs, magnetic resonance imaging findings correlated with an established technetium bone scan grading system and more precisely defined the anatomic location and extent of injury. We identified clinical symptoms, such as pain with daily ambulation and physical examination findings, including localized tibial tenderness and pain with direct or indirect percussion, that correlated with more severe tibial stress injuries. When clinically warranted, we recommend magnetic resonance imaging over bone scan for grading of tibial stress lesions in runners. Magnetic resonance imaging is more accurate in correlating the degree of bone involvement with clinical symptoms, allowing for more accurate recommendations for rehabilitation and return to impact activity. Additional advantages of magnetic resonance imaging include lack of exposure to ionizing radiation and significantly less imaging time than three-phase bone scintigraphy.

Micronutrients and exercise: anti-oxidants and minerals

Exercise has been shown to increase indirect measures of lipid peroxidation. However, exercise and training appear to augment the body's anti-oxidant defence system. Whether this augmented defence system can keep up with the increase in lipid peroxidation with exercise is not known. Iron depletion is experienced by many athletes, especially female endurance athletes and adolescents, but iron deficiency anaemia is rare. Iron depletion could affect the ability to train and recover from strenuous exercise, but this has not been examined. There is a concern that female athletes, especially adolescents, are not ingesting sufficient calcium, and this may affect the development of peak bone mass and increase the risk of bone fractures. Further research is needed on mineral and trace mineral intake and loss in athletes. It appears that most athletes have adequate status of chromium, zinc, phosphate and magnesium. Athletes who are restricting energy intake to achieve a low body mass (for example, endurance runners), may not have adequate vitamin or mineral status. More data are needed on vitamin/mineral status of athletes from underdeveloped countries. The general recommendation for athletes is that foods rich in anti-oxidants and minerals should be ingested rather than supplements.

Effects of free mobilization and low- to high-intensity treadmill running on the immobilization-induced bone loss in rats

After an immobilization period of 3 weeks, the effects of free remobilization (8 weeks) as well as low- and high-intensity treadmill running on the bone mineral content (BMC) and density (BMD) of the hindlimbs of Sprague-Dawley rats (n = 70) were studied using a dual-energy x-ray absorptiometric scanner. In the low-intensity running program, the rats were allowed to move freely in the cage for 1 week, after which they started to run on a treadmill twice a day for 7 weeks. The speed of the treadmill was 20 cm/s, with an uphill inclination of 10 degrees. The running time was gradually increased from 20 minutes per session to 45 minutes per session. In the high-intensity group, the program was similar, with the exception that the speed of the treadmill was 30 cm/s, with an uphill inclination of 30 degrees. Immobilization for 3 weeks produced a significant BMC and BMD loss in the immobilized left femur and tibia (mean loss 9.6%, p < 0.001) but did not affect the right free limbs. Both low- and high-intensity running restored mineral content in the immobilized limb; however, an average 5% difference (p < 0.05) in mineral content of the right and left limb bones persisted. In the running groups, the values for the immobilized left limbs were at the same level or exceeded (range 3.8-11.6%, p < 0.05-0.01) and those of the free right limbs exclusively exceeded (range 5.3-15.9%, p < 0.05-0.01) the corresponding values of the age-matched control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Extended duration of vertical position might impair bone metabolism

Bone-remodelling is markedly influenced by vectors of gravitational forces. Sleep-deprivation, common during military training, involves a change in the normal balance between horizontal and vertical forces enacting on the skeleton. Stress fractures are likewise prevalent among army recruits. In order to investigate the impact of sleep-deprivation on bone-metabolism, three groups of young, healthy volunteers were selected to exercise the following: 63 h of sleeplessness (17 participants, group A); vertical sleep in a seated position for three consecutive nights (9 participants, group B); controls who slept 6 h a night horizontally (14 participants, group C). During periods of wakefulness, all participants were kept in an upright position. Twenty-four hours' urine collection was strictly observed from two days prior to the experiment until two days after it (1 week). Changes in levels of the most characteristic bone-metabolites, calcium and hydroxyproline indicate an increased bone-resorption in the two experimental groups, but not in controls. The calcium excreted in the fasting urine peaked significantly at 72 h after the beginning of the experiment (+ 170% in group A; + 68% in group B, relative to the basal level). Qualitatively, similar results were obtained with hydroxyproline. On an individual basis, approximately 40% of the participants in either group responded by exceeding urinary-calcium elevation. A comparison of pre-test bone-density between responders and non-responders, reveals a significantly lower bone-density (-5%) in calcium and hydroxyproline excretors. These results suggest a pre-disposition to bone-resorption associated with responsiveness to changes in the balance between gravitational forces.

The female triad. Eating disorders, amenorrhea, and osteoporosis

There are certainly challenges facing all of those involved in athletics in the years to come. Eating disorders and amenorrhea and their increased long-term risks of developing osteoporosis are concerns that face female athletes and are are areas where further research is needed. At this point in time, so little is known compared with what remains unknown, and for the most part, the situation remains somewhat dismal. It is unclear what the mechanisms are that explain the amenorrhea that occurs with intense exercise. It is also unclear what role estrogen therapy has in these individuals and whether it is reasonable to allow these athletes to continue to participate by using only estrogen therapy as a means to prevent further bone loss. It will certainly be necessary to devote further research into these issues so clear-cut guidelines can be established. What we do know is somewhat alarming, yet if recognition of these problems is made, early intervention and monitoring are possible, and it is hoped, irreversible bone loss can be prevented. Athletes, coaches, and parents need further education so these disorders can be identified quickly, and further therapy can be instituted if indicated.

Bone fragility: assessment of risk and strategies for prevention

OBJECTIVE

To review the literature related to risk factors for bone fragility and strategies for prevention.

DATA SOURCES

Computerized searches.

STUDY SELECTION

All human research articles from indexed journals in the English language related to the topics in this review and published after 1982 (except for earlier classic pieces) were evaluated.

DATA EXTRACTION

The author extracted data independently using tables that included the following headings: author, year, design, sample size, age range of subjects, results, and comments. Power analyses were done on all reports that included enough information.

DATA SYNTHESIS

The following are determinants of bone fragility: peak bone mass, genetic influences, hormonal status, dietary factors, exercise patterns, and personal exposures.

CONCLUSIONS

Women should be informed of the risk factors and helped to determine whether they are at risk for osteoporosis. All women, starting with young girls, should be taught what methods can be used to decrease their risk. Additional research is needed on methods of improving bone health and decreasing risk.

Bone mineral density in young women with long-standing amenorrhea: limited effect of hormone replacement therapy with ethinylestradiol and desogestrel

To assess bone mineral density (BMD) at different skeletal sites in women with hypothalamic or ovarian amenorrhea and the effect of estrogen-gestagen substitution on BMD we compared BMD of 21 amenorrheic patients with hypothalamic or ovarian amenorrhea with that of a control population of 123 healthy women. All amenorrheic patients were recruited from the outpatient clinic of the Division of Gynecological Endocrinology at the University of Berne, a public University Hospital. One hundred and twenty-three healthy, regularly menstruating women recruited in the Berne area served as a control group. BMD was measured using dual-energy X-ray absorptiometry (DXA). At each site where it was measured, mean BMD was lower in the amenorrheic group than in the control group. Compared with the control group, average BMD in the amenorrheic group was 85% at lumbar spine (p < 0.0001), 92% at femoral neck (p < 0.02), 90% at Ward's triangle (p < 0.03), 92% at tibial diaphysis (p < 0.0001) and 92% at tibial epiphysis (p < 0.03). Fifteen amenorrheic women received estrogen-gestagen replacement therapy (0.03 mg ethinylestradiol and 0.15 mg desogestrel daily for 21 days per month), bone densitometry being repeated within 12-24 months. An annual increase in BMD of 0.2% to 2.9% was noted at all measured sites, the level of significance being reached at the lumbar spine (p < 0.0012) and Ward's triangle (p < 0.033). In conclusion BMD is lower in amenorrheic young women than in a population of normally menstruating, age-matched women in both mainly trabecular (lumbar spine, Ward's triangle, tibial epiphysis) and mainly cortical bone (femoral neck, tibial diaphysis).(ABSTRACT TRUNCATED AT 250 WORDS)

Special problems of the female athlete

The number of women of all ages participating in physical activity is consistently increasing. Although there are numerous benefits to physical activity, specific problems may occur along the various stages of the female athlete's life, which need special attention. A remarkably late menarche, exaggerated beyond the expected genetic predisposition and a high prevalence of abnormal or absent menstrual cycles is seen in athletes, especially in dancers and long distance runners. Reproductive system dysfunction is associated with multiple factors, of which nutritional intake and caloric balance seem to be of a special importance. A high proportion of athletes suffer from pathological eating behaviours and there is an overlap between many features of anorexic patients and highly active athletes. The pathophysiology seen in most cases is hypo-oestrogenism due to suppression of the GnRH pulse generator. The mechanism(s) causing this reversible hypothalamic dysfunction are yet unknown. Of major concern are the skeletal abnormalities, including failure to reach peak bone mass, reduced bone density, scoliosis and stress fractures as a result of prolonged hypo-oestrogenism. Hormone replacement may be indicated in cases in which reduction of exercise or weight gain is not feasible or unsuccessful. Other populations that need special precautions are pregnant athletes and older women.

Bone mass measurement for premenopausal women

Bone mass measurement is a useful tool in determining the risk of fracture. However, there are questions about whether or not bone mass measurement should be used in premenopausal women. Part of the problem concerns the issue of whether or not bone mass or bone density falls prior to menopause. Significant prospective data are still being gathered on this issue, which is hotly debated. In addition, even if there is a loss of bone density prior to menopause, it is not evident what clinical strategy would result from the measurement. At present, therefore, it seems prudent only to measure bone mass of women who have significantly impaired ovarian function or who are approaching menopause.

Position of the American Dietetic Association and the Canadian Dietetic Association: nutrition for physical fitness and athletic performance for adults

The importance of diet and healthful food choices in optimizing health status, fitness levels, and athletic performance has been recognized by both participants and professionals. There continues to be a need for the interpretation of new research findings in this fast-growing discipline and for the dissemination of nutrition information and training techniques for a broad spectrum of individuals involved in various forms of physical activity. The registered dietitian who has specialized in exercise physiology and sports nutrition has the knowledge and counseling skills to act as the provider of this nutrition information. Additional information may be obtained in the Sports Nutrition Manual, 2nd edition, published by The American Dietetic Association and the Sports and Cardiovascular Nutrition dietetic practice group as well as in Sport Nutrition for the Athletes of Canada, published by the Sport Nutrition Advisory Committee of the Sports Medicine and Science Council of Canada.

Managing Tibial Stress Fractures

In brief Tibial stress fractures often occur in Patients who participate in running and jumping sports. With rest, most stress fractures heal without incident, though midshaft fractures are more resistant to healing. Bone scans are usually required to confirm the diagnosis. Relative rest, strength training, proper footwear, and treating underlying risk factors are the mainstays of treatment. A new treatment option is a pneumatic brace that the patient can wear when he or she returns to play. Physicians should be prepared to counsel competitive athletes about the risks of returning to play too soon.

Spine and femur density and broadband ultrasound attenuation of the calcaneus in normal Spanish women

Bone density of the spine and femoral neck and broadband ultrasound attenuation of the calcaneus were measured in 111 normal Spanish women between the ages of 30 and 70 years. The cross-sectional study showed that spine and hip density decreased by 36 and 29%, respectively, and the ultrasound attenuation value decreased by 32% between 30 and 70 years of age. The rate of bone loss at the three sites was significant in women over age 50 and in postmenopausal women. These normative data will be helpful in assessing bone mass in Spanish women suspected of having osteoporosis.

A cruciate ligament injury produces considerable, permanent osteoporosis in the affected knee

Bone mineral density (BMD) and clinical status of 42 patients treated surgically 10-11 years earlier for an acute knee ligament injury were determined. The BMD was measured at the spine (L2-4) and the femoral neck, distal femur, patella, proximal tibia, and calcaneus of both lower extremities using dual-energy x-ray absorptiometric (DXA) scanner. The relative BMD results of the injured knee were correlated with sex, age, activity level, knee stability, and functional scores of the patient. In the 11 patients with moderate injury (isolated rupture of the medial collateral ligament), the BMDs of the injured and uninjured extremities were equal. In the 31 patients with severe injury (cruciate ligament rupture), the BMDs were significantly lower in the injured knee: distal femur, -6.0% (p = 0.0000); patella, -9.0% (p = 0.0000); and proximal tibia, -3.3% (p = 0.0012). Neither the femoral neck nor the calcaneus showed any differences. There were no significant differences either between men and women or between patients with different activity levels. The relative BMDs of the injured knee did not correlate with age or static knee stability but correlated significantly (r = 0.42-0.78, p < 0.01-0.001) with the functional scores of the same knee: the better the knee function in comparison with the healthy knee, the higher the relative BMD. The spinal BMDs corresponded with the age-adjusted reference values of the used densitometry. In conclusion, a severe knee ligament injury results in permanently decreased BMD in the injured knee. Other parts of the same extremity and lumbar spine are not affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Stress fractures in the athlete. Diagnosis and management

Stress fractures can be a troublesome injury for the sports medicine clinician. The first description was in military personnel, but recently there is an increasing awareness and diagnosis of stress fractures in the athletic population. Stress fractures have been described in all extremities. Some fractures appear to have a degree of sports specificity. Bone is a dynamic tissue which strengthens and remodels in response to stress. Maladaptation to stress causes osteoclastic activity to supersede osteoblastic activity, thereby allowing weakening of the bone. These areas of weakening may fracture and create prodromal symptoms and clinical findings. Localised pains of insidious onset which are activity related are the hallmarks in the clinical history. The physical examination can exhibit localised tenderness, redness and swelling. Radiographs can be negative for up to 4 months. The gold standard for diagnosis is the triple phase 99mtechnetium bone scan. The treatment of a stress fracture is usually conservative. Very few cases require surgical management. The algorithm of conservative management includes: rest, appropriate education for treatment and preventive care, analgesics, serial radiographs, icing and physical therapy modalities, appropriate exercise to prevent detraining, rehabilitation and a regimented return to participation and competition.

Can vigorous exercise play a role in osteoporosis prevention? A review

Part of the reduction in bone density observed in older people is due to disuse rather than the aging process itself. While some mechanical stress is needed to maintain optimal bone density, it is not clear just which types of exercise are most valuable or whether appropriate exercise might reduce the need for estrogen therapy in postmenopausal women. Cross-sectional studies. Physical activity, aerobic fitness, and strength have all been correlated with bone density. Young people who use a specific part of the body in vigorous exercise exhibit enhanced bone density in that part of the body, but not necessarily in other regions. Older people who have been active for many years seem to exhibit generally enhanced bone density. Prospective studies. Most regimens which used vigorous aerobic and strength training enhanced bone density, but walking is relatively ineffective for prevention of postmenopausal bone loss. Most studies using specific bone-loading exercise have shown substantial increases in bone density at the specific sites loaded. Elderly people seem capable of responding favorably to vigorous exercise. No direct comparisons of exercise and estrogen therapy have been reported. Excessive exercise. Extremely high volumes of exercise may overwhelm a person's adaptive capacity, leading to stress fractures. For example, young women athletes who suffer from menstrual dysfunction exhibit reduced bone density and musculoskeletal disorders. Clinical implication. Although the evidence is far from conclusive, an exercise regimen should probably include vigorous total body exercise, including strength and aerobic training.

Crystalluria in marathon runners. IV. Black subjects

Crystal sizes (scanning electron microscopy) and distributions (Coulter Counter) as well as 24-h urinary sodium (Na) and calcium (Ca) excretions (flame atomic absorption) were determined in a group of black South African runners immediately after a marathon and again 3 weeks later. White runners and black and white control subjects were included in the study. Particle volume-size histograms for black controls and black runners were identical. There was no significant difference in the Na excretion of all the groups. However, while urinary Ca excretion was significantly raised in white runners relative to white controls, Ca excretion in black runners was unchanged relative to their controls. It is postulated that the lower rates of urinary Ca excretion may result from lower rates of Ca resorption from bone in response to the cyclical loading of running in black marathon runners. The results of this study suggest that black marathon runners are not prone to the same increased risk of renal stone formation as are white runners.

Bone Mass, External Loads, and Stress Fracture in Female Runners

Increased incidence of stress fracture has been reported for amenorrheic runners, while some studies have reported decreased spinal bone mass in amenorrheic runners. Based on results from these studies, one tends to associate decreased spinal bone mass with an increased risk of stress fracture. The present study compared regional bone mass and external loads during running between six female runners reporting a history of stress fracture (seven tibial and three femoral neck) and eight female runners with no history of stress fracture. Dual photon absorptiometry measures indicated significantly greater spinal (L2-L4) and femoral neck bone mineral density in stress fracture subjects (p<0.05) but no differences between groups for tibial bone density. Normalized forces recorded from Kistler force plates indicated significantly greater vertical propulsive, maximal medial, lateral, and posterior forces for stress fracture subjects during running (p<0.05).

Eating and weight disorders in the female athlete

This paper presents an overview of eating disorders, including definitions, clinical criteria for appropriate diagnosis, and a discussion of the potential for increased risk for eating disorders in special populations of female athletes. This is followed by a discussion of the prevalence of eating disorders in normal and athletic populations. From this discussion, it seems clear that female athletes in endurance or appearance sports are at an increased risk for disordered eating. Finally, the paper focuses on related disorders--a triad associating eating disorders, menstrual dysfunction, and bone mineral disorders. It is clear that secondary amenorrhea is associated with malnutrition and disordered eating. Further, bone mineral disorders are related to menstrual dysfunction. Disordered eating may represent the initiating factor of this triad.

Minerals: exercise performance and supplementation in athletes

This paper examines whether mineral supplements are necessary for athletes, and whether these supplements will enhance performance. Macrominerals (calcium, magnesium, and phosphorus) and trace minerals (zinc, copper, selenium, chromium, and iron) are described. Calcium supplements are important for the health of bones. Athletes tend to have enhanced calcium status as assessed by bone mineral density, with the notable exception of female amenorrhoeic athletes. Magnesium status is adequate for most athletes, and there is no evidence that magnesium supplements can enhance performance. Phosphorus status is adequate for athletes. Phosphorus supplementation over an extended period of time can result in lowered blood calcium, however, some studies have shown that acute 'phosphate loading' will enhance performance. Athletes may have a zinc deficiency induced by poor diet and loss of zinc in sweat and urine. Limited data exist on the relationship of performance and zinc status. Widespread deficiencies in copper have not been documented, and there are no data to suggest that copper supplementation will enhance performance. There is no reason to suspect a selenium deficiency in athletes. The relationship between selenium status and performance has not been established, but selenium may play a role as an antioxidant. Because of the low intakes of chromium for the general population, there is a possibility that athletes may be deficient. Exercise may create a loss in chromium because of increased excretion into the urine. Many athletes, particularly female, are iron depleted, but true iron deficiencies are rare. Iron depletion does not affect exercise performance but iron deficiency anaemia does. Iron supplements have not been shown to enhance performance except where iron deficiency anaemia exists. In conclusion, poor diets are perhaps the main reason for any mineral deficiencies found in athletes, although in certain cases exercise could contribute to the deficiency. Mineral supplementation may be important to ensure good health, but few studies have definitively documented any beneficial effect of mineral supplementation on performance.