Search PubMed⌕ Search

Biomedical subjects

P Kannus

Publications and source records attributed to P Kannus.

At least 55 records · Page 3Linked to original sources
PubMed2000

High-impact exercise and bones of growing girls: a 9-month controlled trial.

The maximum amount of bone a person can obtain during the first two decades of life is an important determinant of bone mass in later life, and an increase in peak bone mass has been associated with decreased risk for osteoporotic fractures. It is known that growth of bone and thus development of peak bone mass are strongly controlled by genetic factors, but information on the role of environmental factors, such as exercise and nutrition, (e.g., exercise) on growing bone is limited. We tested a hypothesis that in growing girls the benefit of mechanical loading on bone mineral mass and bone strength is better before rather than after the menarche. Sixty-four girls (25 premenarcheal, 39 postmenarcheal) carried out a supervised 9-month step-aerobic program (two sessions per week), each session complemented with additional jumps. Sixty-two girls (33 premenarcheal, 29 postmenarcheal) served as controls. Bone mineral content (BMC) at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DXA). In addition, the cortical density (CoD, mg/cm3) and cortical cross-sectional area (CoA, mm2) and the density-weighted polar section modulus (BSI, mm3) of the tibial midshaft were determined by peripheral quantitative tomography (pQCT). In the premenarcheal girls, BMC increased statistically significantly more in the trainees than controls at the lumbar spine (p = 0.012) (8.6% vs 5.3%) and femoral neck (p = 0.014) (9.3% vs 5.3%). In the tibial midshaft, the intergroup differences (CoD, CoA and BSI) were not significant. The postmenarcheal girls showed no significant post-training intergroup differences in any of the bone parameters (BMC increased in the lumbar spine 6.0% vs 4.9%; femoral neck 3.4% vs 3.2%; and trochanter 2.6% vs 3.5%). Although a large proportion of bone mineral increase in the growing girls of this study was attributable to growth itself, this 9-month exercise intervention showed that a clear and large additional bone gain could be obtained in exercising premenarcheal girls, but not in exercising postmenarcheal girls. In other words, exercise seemed more beneficial for additional bone mineral acquisition before menarche (i.e., during the growth spurt) rather than after it.

Absorptiometry, Photon↗
PubMed2000

The injury mechanisms of osteoporotic upper extremity fractures among older adults: a controlled study of 287 consecutive patients and their 108 controls.

The risk factors for falls in older adults are well known but knowledge on the direct injury mechanisms that result in various osteoporotic fractures has been very sparse. The purpose of this study was therefore to clarify the injury mechanisms of osteoporotic upper extremity fractures of older adults and to compare these mechanisms with those of the control fallers, and in this way to obtain reliable insight into the etiology and pathogenesis of upper extremity fractures and thus to enable fracture prevention. One hundred and twelve patients with a fresh fracture of the proximal humerus, 65 patients with an elbow fracture, 110 patients with a wrist fracture and 108 controls (no fracture, or a fracture other than the case fracture) were interviewed and examined between September 1995 and December 1997. The inclusion criteria of the subjects were that the patient was 50 years of age or older at the time of the accident, and that the fracture/injury had occurred as a result of low-energy trauma (typically a fall from standing height or less) within a week before the interview and examination. In 97% of patients with a proximal humerus or elbow fracture, and in all patients (100%) with a wrist fracture, the fracture was a result of a fall. In the control group this figure was 93%. In a polychotomous logistic regression analysis the intergroup differences in the fall directions (adjusted by gender, age and functional capacity) were statistically highly significant (chi 2 = 43.6, d.f. = 15, p < 0.001). Most of the patients with a proximal humerus fracture or elbow fracture reported that they had fallen 'obliquely forward' (43% and 38%) or 'to the side' (29% and 26%), whereas in the wrist fracture group the main fall direction was also 'obliquely forward' (34%) but the other fall directions (i.e., 'forward', 'to the side', 'obliquely backward' and 'backward') were quite equally represented (13-19%). The odds ratio (OR) for an obliquely forward fall resulting in a proximal humerus fracture was 3.5 [95% confidence interval (CI) 1.4-9.2), as compared with the fall directions of the controls and the 'obliquely backward' fall direction. In a logistic regression analysis the patients with a wrist fracture managed to break their fall (e.g., with an outstretched arm) more frequently than the patients in the other groups (OR 3.9; 95% CI 2.0-7.3). The patients with a proximal humerus fracture, in turn, managed to break their fall less frequently than the controls (OR 0.33; 95% CI 0.14-0.80). The same was true of the patients with an elbow fracture, although the difference was not significant (OR 0.49%; 95% CI 0.19-1.3). As objective evidence for a direct fall-induced impact on the fracture site, 68% of patients with a proximal humerus fracture revealed a fresh subcutaneous hematoma on the shoulder/upper arm, while such a hematoma was rare in the controls (2%) (p < 0.001). Correspondingly, 62% of patients with an elbow fracture showed a similar hematoma on the elbow area, while this was seen in none of the controls (p < 0.001). In patients with a wrist fracture a hand/wrist hematoma was seen in 58% of the victims, as compared with 18% of the controls (p < 0.001). The study shows that the most typical osteoporotic upper extremity fractures of older adults have their specific injury mechanisms. A great majority of these fractures occur as a result of a fall and a subsequent direct impact of the fractured site. Effective fracture prevention could be achieved by minimizing the obvious risk factors of falling and reducing the fall-induced impact force with injury site protection.

Accidental Falls↗
PubMed2000

Epidemiology of osteoporotic pelvic fractures in elderly people in Finland: sharp increase in 1970-1997 and alarming projections for the new millennium.

The purpose of our epidemiologic study was to determine the current trend in the number and incidence of osteoporotic pelvic fractures in Finland, a country with a Caucasian population of 5 million. Thus, all Finns 60 years of age or older who were admitted to hospitals in 1970-1997 for primary treatment of a first osteoporotic pelvic fracture were selected from The National Hospital Discharge Register. In each year of the study, the number and the age-specific and age-adjusted incidences of fractures were expressed as the number of. patients per 100,000 individuals. The total number of osteoporotic pelvic fractures increased considerably in Finland during the study period, from 128 in 1970 to 913 in 1997, an average increase of 23% a year. The corresponding fracture incidence (per 100,000 persons 60 years of age or older) was 20 in 1970 and 92 in 1997. The mean age of the patients also increased, from 74 years (1970) to 80 years (1997). Despite this, the age-adjusted incidence of osteoporotic pelvic fractures also showed a steady increase from 1970 to 1997: in women, from 31 to 103, and in men, from 13 to 38 (relative increases were 232% and 192%, respectively). If this trend continues, the current number of osteoporotic pelvic fractures in this country (about 900 fractures per year) may treble by the year 2030 (about 2,700 fractures per year). We conclude that the number of osteoporotic pelvic fractures in elderly Finns is increasing at a rate that cannot be explained simply by demographic changes and therefore effective preventive measures should be urgently initiated to control the increasing burden of these age-related fractures.

Age Distribution↗
PubMed2000

Does childhood and adolescence provide a unique opportunity for exercise to strengthen the skeleton?

Osteoporosis is a major, and increasing, public health problem. In this review we examine the evidence that childhood physical activity is an important determinant of bone mineral in adult years, and as such, may help to prevent osteoporosis. Animal studies provide incontrovertible evidence that growing bone has a greater capacity to add new bone to the skeleton than does adult bone. Observational studies in children undertaking routine physical activity and cross-sectional athlete studies in young sportspeople both reveal that activity is positively associated with bone mineral density (BMD). Longitudinal studies in pre- and peripubertal gymnasts reveal BMD gains far in excess of those that can be achieved in adulthood. However, such studies permit only limited conclusions as they contain the potential for selection bias and can be confounded by other determinants of bone mineral (e.g. dietary and lifestyle factors). Thus, research comparing inter-individual playing-to-nonplaying arm differences in bone mineral (e.g., in racquet sports) have proven to be extremely useful. These studies suggest that the BMD differences are clearly greater when bone is subjected to mechanical loading prior to the end of puberty and longitudinal growth of the body (in women, before menarche) rather than after it. Tanner stage II and III appears to be the maturational stage when the association between exercise and BMD becomes manifest in most adolescents. Do conclusions drawn from athlete studies apply to the general population? Randomised intervention studies of physical activity and bone mineral accrual in normal children confirm that childhood activity is strongly associated with bone mineral accrual. Furthermore, some retired athlete studies and a detraining study suggest that adolescent bone gain may, at least partly, persist despite reduced adult physical activity. Mechanisms that may underlie the association between childhood physical activity and bone mineral accrual are outlined. Thus, it appears that physical activity during the most active period of maturity (with respect to longitudinal growth of the body) plays a vital role in optimising peak bone mass and that benefits may extend into adulthood.

Adult↗
PubMed2000

Exercise-induced bone gain is due to enlargement in bone size without a change in volumetric bone density: a peripheral quantitative computed tomography study of the upper arms of male tennis players.

Bilateral bone characteristics of the humerus (proximal, shaft, and distal sites) and radius (shaft and distal sites) in 12 former Finnish national-level male tennis players (mean age 30 years) and their 12 age-, height-, and weight-matched controls were measured with peripheral quantitative computed tomography (pQCT). The pQCT variables analyzed were bone mineral content (BMC), total cross-sectional area of bone (Tot.Ar), cross-sectional area of the marrow cavity (M.Cav.Ar), cortical bone (Co.Ar) and trabecular bone (Tr.Ar), volumetric density of cortical (Co.Dn) and trabecular (Tr. Dn) bone, cortical wall thickness (Co.Wi.Th), bone strength index (BSI), and principal moments of inertia (I(min) and I(max)). In the players, significant side-to-side differences, in favor of the dominant (playing) arm, were found in BMC (ranging 14%-27%), Tot.Ar (16%-21%), Co.Ar (12%-32%), BSI (23%-37%), I(min) (33%-61%), and I(max) (27%-67%) at all measured bone sites, and in Co.Wi.Th. (5%-25%) at the humeral and radial shafts, and distal humerus. The side-to-side M.Cav.Ar difference was significant at the proximal humerus (19%) and radial shaft (29%). Concerning the players' Co.Dn and Tr.Dn, the only significant side-to-side difference was found in the Co.Dn of the distal humerus, with the playing arm showing a slightly smaller Co.Dn than the nonplaying arm (-2%). In controls, significant dominant-to-nondominant side differences were also found, but with the majority of the differences being rather small, and significantly lower than those of the players. In conclusion, despite the large side-to-side differences in BMC, the volumetric bone density (Co.Dn, Tr.Dn) was almost identical in the dominant and nondominant arms of the players and controls. Thus, the players' high playing-arm BMC was due to increases in the Tot.Ar, M.Cav.Ar, Co.Ar, and CW.Th. In other words, the playing arm's extra bone mineral, and thus increased bone strength, was mainly due to increased bone size and not due to a change in volumetric bone density. These upper arm results may not be generalized to the entire skeleton, but the finding may give new insight into conventional dual-energy X-ray absorptiometry (DXA)-based bone density measurements when interpreting the effects of exercise on bone.

Adult↗
PubMed2000

Anterior knee pain 7 years after an anterior cruciate ligament reconstruction with a bone-patellar tendon-bone autograft.

In order to evaluate the occurrence and predicting factors of anterior knee pain in patients after an anterior cruciate ligament reconstruction with a bone-patellar tendon-bone autograft, a functional, clinical and radiographic evaluation was performed on 91 patients on average 7 years after the surgery. Also, the isokinetic muscle torque was measured. At 7 years, anterior knee pain, as classified by the International Knee Documentation Committee (IKDC), was absent in 40 patients, mild in 47 patients, and moderate in 4 patients. None was classified as suffering from severe anterior knee pain. In the logistic regression analysis of predicting factors (forward-stepping), knee extension torque deficit of the operated limb was the only factor that showed significant association with anterior knee pain. The other objective measurements of the knee (flexion torque deficit, range of motion, stability evaluation, and radiographic evaluation of the knee) were not associated with anterior knee pain. Subjectively and not surprisingly, the patients without anterior knee pain were more often satisfied with the overall outcome than the patients with anterior knee pain. Also, the Lysholm and Marshall knee scores and the final outcome in the IKDC rating scale were significantly better in patients without than with anterior knee pain.

Adult↗
PubMed2000

Structure of the tendon connective tissue.

Tendons consist of collagen (mostly type I collagen) and elastin embedded in a proteoglycan-water matrix with collagen accounting for 65-80% and elastin approximately 1-2% of the dry mass of the tendon. These elements are produced by tenoblasts and tenocytes, which are the elongated fibroblasts and fibrocytes that lie between the collagen fibers, and are organized in a complex hierarchical scheme to form the tendon proper. Soluble tropocollagen molecules form cross-links to create insoluble collagen molecules which then aggregate progressively into microfibrils and then into electronmicroscopically clearly visible units, the collagen fibrils. A bunch of collagen fibrils forms a collagen fiber, which is the basic unit of a tendon. A fine sheath of connective tissue called endotenon invests each collagen fiber and binds fibers together. A bunch of collagen fibers forms a primary fiber bundle, and a group of primary fiber bundles forms a secondary fiber bundle. A group of secondary fiber bundles, in turn, forms a tertiary bundle, and the tertiary bundles make up the tendon. The entire tendon is surrounded by a fine connective tissue sheath called epitenon. The three-dimensional ultrastructure of tendon fibers and fiber bundles is complex. Within one collagen fiber, the fibrils are oriented not only longitudinally but also transversely and horizontally. The longitudinal fibers do not run only parallel but also cross each other, forming spirals. Some of the individual fibrils and fibril groups form spiral-type plaits. The basic function of the tendon is to transmit the force created by the muscle to the bone, and, in this way, make joint movement possible. The complex macro- and microstructure of tendons and tendon fibers make this possible. During various phases of movements, the tendons are exposed not only to longitudinal but also to transversal and rotational forces. In addition, they must be prepared to withstand direct contusions and pressures. The above-described three-dimensional internal structure of the fibers forms a buffer medium against forces of various directions, thus preventing damage and disconnection of the fibers.

Collagen↗
PubMed2000

Tenascin-C in the pathobiology and healing process of musculoskeletal tissue injury.

Tenascin-C (TN-C) is a hexabrachion-shaped extracellular matrix (ECM) protein which has very restricted expression in normal musculoskeletal tissues, but is expressed in large quantities in these tissues during embryogenesis as well as during regenerative and healing processes. TN-C is an elastic protein which has a number of binding sites for other extracellular matrix proteins as well as for cell membrane adhesion receptors. In addition, it can be stretched to several times its resting length, the ability of which is attributed to the stretch-induced unfolding of its fibronectin type III domains. In the musculoskeletal tissues, TN-C is present in the regions where high mechanical forces are transmitted from one tissue component to another, such as the myotendinous and osteotendinous junctions. Not surprisingly, it was recently presented that the expression of TN-C in the musculoskeletal tissues is regulated by the mechanical strain applied to their cells. Thus, taking into account the flexible structure of the TN-C and its site-specific expression pattern at sites exposed to heavy mechanical loads, TN-C is likely to play an important role in providing elasticity to the musculoskeletal tissues. This feature has a special significance in the degenerative and regenerative processes where the normal biomechanical environment of the musculoskeletal tissue is temporarily interrupted by injury. The rapidly increasing understanding of the structure and function of the ECM protein TN-C may well bring important insights into the clinical treatment of sports injuries in the future.

Animals↗
PubMed2000

Osteoporotic fractures of the proximal humerus in elderly Finnish persons: sharp increase in 1970-1998 and alarming projections for the new millennium.

We determined the current trends in the number and incidence of osteoporotic fractures of the proximal humerus in Finland by collecting from the National Hospital Discharge Register all patients 60 years of age or more who were admitted to Finnish hospitals in 1970-1998 for primary treatment of such fractures. The fracture was defined osteoporotic if it was caused by a low-energy trauma only, i.e., a fall from standing height or less. The number and incidence (per 10(5) persons) of fractures increased sharply from 208 (number) and 32 (incidence) in 1970 to 1,105 and 110 in 1998. Even after the age-adjustment, the incidence of fractures showed a clear increase: in women from 50 in 1970 to 133 in 1998, and in men from 14 in 1970 to 49 in 1998. If this trend continues, there will be three times more osteoporotic fractures of the proximal humerus in Finland in the year 2030 than there were in 1998.

Aged↗
PubMed2000

Unintentional injury deaths in an adult Finnish population from 1971-1997.

We investigated the trends in age-standardized rates (per 100,000 persons-years) of unintentional injury deaths in adult Finns from 1971-1997. In 1971, the leading category of unintentional injury resulting in death among Finnish men was road traffic accidents (age-standardized death rate 47 per 100,000 person-years). This rate has declined sharply, reaching 13 per 100,000 person-years in 1997. Simultaneously, the rate of fall-induced death among men gradually increased from 17/100,000 person-years in 1971 to 21/100,000 person-years in 1997. In 1997 the death rate from falls in men was greater than that of any other category of injury. In 1971, traffic caused fewer deaths in women (rate 17/100,000 person-years) than men, and declined from there to a rate of 6/100,000 person-years in 1997. Concurrently the rate of fall-induced deaths in women also decreased, from 27/100,000 person-years in 1971 to 17/100,000 person-years in 1997. Falling, however, was the leading cause of injury-related death in 1997. Thus, in the period 1971-1997, falls replaced road traffic accidents as the leading cause of unintentional injury death in Finland.

Adolescent↗
PubMed2000

Childhood deaths and injuries in Finland in 1971-1995.

BACKGROUND: This study examined the recent nationwide trends for the absolute number and the age- and sex-specific incidence rates of the fatal and serious non-fatal injuries among 0-14 year old children in Finland in 1971-1995. METHODS: We selected from Official Cause-of-Death Statistics and National Hospital Discharge Register children aged 0-14 years who died or required treatment at a hospital department because of an injury in 1971-1995. The number of Finnish children was 1.1 million in 1971, and 1.0 million in 1995. RESULTS: During the entire study period injuries were the leading cause of death in children aged 1-14 years, but not in infants. However, in these years the incidence (per 100 000 people) of fatal injuries in Finnish children decreased considerably in all age groups and both sexes, in girls from 20.1 in 1971 to 4.6 in 1995, and in boys from 36.7 in 1971 to 9.3 in 1995. In 1995, 41% of all the injurious deaths among 0-14 year old Finnish children were motor vehicle accidents, 12% were drownings, and 24% intentional injuries. The overall number and incidence of serious non-fatal injuries among Finnish children showed no clear trend change in 1971-1995. The mean hospitalization time of injured children shortened between 1971 and 1995, from 7.4 days to 2.7 days. CONCLUSIONS: We conclude that the number and incidence of fatal childhood injuries have decreased dramatically in Finland between 1971 and 1995. The reasons for this positive development are multifactorial, but improved traffic safety and trauma care are probably very important. In children's serious non-fatal injuries the development has not been so encouraging and therefore children's injury prevention should receive continuous intense attention.

Accident Prevention↗
PubMed1999

Genetic factors and osteoporotic fractures in elderly people: prospective 25 year follow up of a nationwide cohort of elderly Finnish twins.

OBJECTIVE: To determine whether genetic factors partly explain variation in risk of osteoporotic fracture, the true end point of the osteoporosis problem. DESIGN: Prospective 25 year follow up of a nationwide cohort of elderly Finnish twins. SETTING: The Finnish twin cohort and the national hospital discharge register, covering the entire 5 million population of Finland. SUBJECTS: All same sex twin pairs born before 1946. The cohort contained 2308 monozygotic and 5241 dizygotic twin pairs (15 098 people) at the beginning of follow up. Main: outcome measure The number and concordance of osteoporotic fractures in the twin pairs, 1972-96. RESULTS: 786 cohort members sustained an osteoporotic fracture. In women, the pairwise concordance rate for fracture (that is, the relative number of twin pairs in whom the fracture affected both twins in a pair) was 9.5% (95% confidence interval 5.3% to 15.5%) in monozygotic pairs and 7.9% (5.2% to 11.4%) in dizygotic pairs. In men, the figures were 9.9% (4.4% to 18.5%) and 2.3% (0.6% to 5.7%). CONCLUSIONS: Susceptibility to osteoporotic fractures in elderly Finns is not strongly influenced by genetic factors, especially in elderly women. The traditional strategy for prevention of osteoporotic fractures-that is, increasing peak bone mass and preventing age related bone loss-should be changed to include new elements such as prevention of falls and protection of the critical anatomical sites of the body when a fall occurs.

Aged↗
PubMed1999

Fall-induced injuries and deaths among older adults.

CONTEXT: Although various fall-induced injuries and deaths among older adults are increasing, little is known about the epidemiology of these events. OBJECTIVE: To determine the trends in the number and incidence of fall-induced injuries and deaths of older adults in a well-defined white population. DESIGN AND SETTING: Secular trend analysis of the population of Finland, using the Finnish National Hospital Discharge Register and the Official Cause-of-Death Statistics of Finland. PARTICIPANTS: All persons aged 50 years or older who were admitted to hospitals in Finland for primary treatment of a first fall-induced injury from the years of 1970 to 1995, and for comparison, all fall-induced deaths in the same age group from the years 1971 to 1995. MAIN OUTCOME MEASURE: The number and the age-specific and age-adjusted incidence rate (per 100000 persons) of fall-induced injuries and deaths in each year of the study. RESULTS: For the study period, both the total and population-adjusted number (per 100000 persons) of Finns aged 50 years or older with fall-induced injury increased substantially. Total fall-induced injuries increased from 5622 in 1970 to 21 574 in 1995, a 284% increase, and the rate increased from 494 to 1398 per 100000 persons, a 183% increase. The age-adjusted incidence also increased in both women (from 648 in 1970 to 1469 in 1995, a 127% increase) and men (from 434 in 1970 to 972 in 1995, a 124% increase). Moreover, the number of deaths due to falls in the overall population increased from 441 in 1971 to 793 in 1995, an 80% increase, and the rate increased from 38 in 1971 to 51 in 1995, a 34% increase. However, after age adjustment the incidence of fall-induced death did not show a clear upward trend. CONCLUSIONS: In a well-defined white population, the number of older persons with fall-induced injuries is increasing at a rate that cannot be explained simply by demographic changes. Preventive measures should be adopted to control the increasing burden of these injuries. Fortunately, the age-adjusted incidence of the fall-induced deaths shows no increasing trend over time.

Accidental Falls↗
PubMed1999

Hip fractures in Finland between 1970 and 1997 and predictions for the future.

BACKGROUND: Hip fractures in elderly people are common worldwide, and the predicted ageing of populations is increasing the burden of these fractures on health-care systems. However, prediction of the true increases in number of patients needing treatment requires exact knowledge of whether the number of hip fractures is rising more rapidly than can be accounted for by demographic changes alone. We aimed to make such a prediction for people aged 50 years or more in Finland. METHODS: All patients aged 50 years or more, who were admitted to hospitals in Finland during 1970-97 for primary treatment of first hip fracture were selected from the National Hospital Discharge Register. The age-specific and age-adjusted fracture incidences were expressed as the number of patients per 100,000 individuals per year, and prediction of the number, and incidence of hip fractures in Finland (population 5 million) until the year 2030 was calculated with a regression model. FINDINGS: The number of hip fractures in Finnish people aged 50 or more rose during the study period, from 1857 in 1970 to 7122 in 1997. The corresponding fracture incidence (per 100,000 people) increased from 163 to 438. The age-adjusted incidence of hip fractures also showed a steady increase from 1970 to 1997: in women, from 292 to 467, and in men, from 112 to 233. If this trend continues, the number of hip fractures in Finland will be almost three-fold higher in the year 2030 than in 1997. INTERPRETATION: The number of hip fractures in elderly Finnish men and women is increasing at a rate that cannot be explained merely by demographic changes. The precise reasons for this are not known, but deterioration in age-adjusted bone-mineral density and strength, with accompanying increase in the age-adjusted incidence of injurious falls of the elderly, could partly account for the development.

Age Factors↗