Stressfrakturen

Bone stress injuries are due to repetitive mechanical overuse of the skeleton and occur as a result of microscopic lesions sustained when bone is subjected to repeated submaximal stress. Over time accumulation of such injuries can lead to bone failure and fractures. Stress-related bone injuries are relatively common among otherwise healthy persons who have recently started new or intensified forms of physical training activities. Stress injuries lead to typical findings on radiography, bone scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI) and need to be discriminated from other conditions, in particular infections and neoplasms. Stress fractures must be differentiated from insufficiency fractures that occur in bones with reduced mechanical resistance or disturbed structure.     

Preventing and managing stress fractures in athletes

Stress fractures are common overuse injuries of bone resulting from the repeated application of submaximal load. Factors that reduce bone strength or increase the load applied to bone can place an athlete at risk of developing a stress fracture. These factors include low bone density, menstrual disturbances, inadequate dietary intake and eating disorders, training errors, inadequate muscle function and biomechanical features. Identification of the at-risk athlete can allow prevention strategies to be implemented. Diagnosis of a stress fracture is generally made clinically but investigations such as bone scan, CT or MRI can be performed to confirm the diagnosis, grade the stage of the bone response and localize the site. Most stress fractures will heal with modified rest and permit return to sport around 8 weeks. However, there is a group of stress fractures that requires additional treatment and special consideration. Treatment of the typical stress fracture requires pain management, modification (or cessation) of the aggravating activity, muscle strengthening and maintenance of aerobic fitness, identification and subsequent modification of risk factors and gradual resumption of bone loading activities. The use of braces has been shown to reduce the time to return to full activity in some lower limb stress fractures. Similarly the use of electrical stimulation and ultrasound may be helpful. Recovery should be monitored clinically.     

Stress fractures in runners

Stress fractures are a relatively common entity in athletes, in particular, runners. Physicians and health care providers should maintain a high index of suspicion for stress fractures in runners presenting with insidious onset of focal bone tenderness associated with recent changes in training intensity or regimen. It is particularly important to recognize “high-risk” fractures, as these are associated with an increased risk of complication. A patient with confirmed radiographic evidence of a high-risk stress fracture should be evaluated by an orthopedic surgeon. Runners may benefit from orthotics, cushioned sneakers, interval training, and vitamin/calcium supplementation as a means of stress fracture prevention.     

Stress fractures in elite male football players

The objective was to investigate the incidence, type and distribution of stress fractures in professional male football players. Fifty‐four football teams, comprising 2379 players, were followed prospectively for 189 team seasons during the years 2001–2009. Team medical staff recorded individual player exposure and time‐loss injuries. The first team squads of 24 clubs selected by UEFA as belonging to the 50 best European teams, 15 teams of the Swedish Super League and 15 teams playing their home matches on artificial turf pitches were included. In total, 51 stress fractures occurred during 1 180 000 h of exposure, giving an injury incidence of 0.04 injuries/1000 h. A team of 25 players can therefore expect one stress fracture every third season. All fractures affected the lower extremities and 78% the fifth metatarsal bone. Stress fractures to the fifth metatarsal bone, tibia or pelvis caused absences of 3–5 months. Twenty‐nine percent of the stress fractures were re‐injuries. Players that sustained stress fractures were significantly younger than those that did not. Stress fractures are rare in men's professional football but cause long absences. Younger age and intensive pre‐season training appear to be risk factors.     

Comparison of stress fractures of male and female recruits during basic training in the Israeli anti-aircraft forces

BACKGROUND: In military basic training, stress fractures are a common orthopedic problem. Female recruits have a significantly higher incidence of stress fractures than do male recruits. Because the Israeli Defense Forces opened traditionally male roles in combat units to female recruits, their high risk for stress fractures is of concern. OBJECTIVE: To compare the prevalence of stress fractures during Israeli Defense Forces anti-aircraft basic training among otherwise healthy young male and female recruits, in terms of anatomic distribution and severity. DESIGN: Ten mixed gender batteries, including 375 male recruits and 138 female recruits, carried out basic training in the Israeli anti-aircraft corps between November 1999 and January 2003. Each battery was monitored prospectively for 10 weeks of a basic training course. During that time, recruits who were suspected of having an overuse injury went through a protocol that included an orthopedic specialist physical examination followed by a radionuclide technetium bone scan, which was assessed by consultant nuclear medicine experts. The assessment included the anatomic site and the severity of the fractures, labeled as either high severity or low severity. RESULTS: Stress fractures were significantly more common among female recruits than among male recruits. A total of 42 male (11.2%) and 33 female (23.91%) recruits had positive bone scans for stress fractures (female:male relative ratio, 2.13; p < 0.001). Pelvic, femur, and tibia fractures were significantly more common among female recruits than among male recruits (p < 0.005). Female recruits had significantly more severe fractures in the tibia (p < 0.05). However, there was no significant difference in the severity of stress fractures in the femur or metatarsals between male and female recruits, as assessed by radionuclide uptake. CONCLUSIONS: We recommend that different training programs be assigned according to gender, in which female recruits would have a lower level of target strain or a more moderate incline of strain in the training program throughout basic training.     

Stress fractures. Identifiable risk factors.

To answer the question why such large differences in stress fracture morbidity rates (2% to 64%) exist in different countries, we prospectively evaluated 312 recruits for possible risk factors for stress fractures. Prior to training, each recruit underwent an evaluation including the following: orthopaedic examination, foot and tibial radiographs, measurements of tibial bone width, bone mineral content, bone density, aerobic physical fitness and leg power, assessments of somatotype and smoking habits, and evaluation of sociological and psychological factors. Using a multivariate analysis, two risk factors were identified: recruits with stress fractures had significantly narrower tibiae (P less than 0.001), and a higher degree of external rotation of the hip (P = 0.016). These two variables were independent and cumulative. Stress fracture morbidity was 17%, 29%, and 45% when neither, one, or both risk factors were present, respectively (P less than 0.001). Identification of these risk factors might explain the susceptibility of some people to stress fractures.     

Stress fractures of the anklein the athlete

Stress fractures of the ankle in the athlete are related to one of several proposed theories. Athletes sustaining these injuries usually participate in impact loading activities. The most common locations for stress fractures involving the ankle joint are the supramalleolar region of the fibula and the medial malleolus. Stress fractures of the distal fibula are usually treated conservatively with rest, activity modifications, and a short period of immobilization. Healing times and return to activity may take up to 12 weeks. Stress fractures of the medial malleolus have a higher rate of delayed unions and nonunions and require a higher degree of monitoring. Operative management has become an accepted method of treating stress fractures of the medial malleolus.     

Stress fractures: classification and management

Stress fractures occur as a result of microdamage secondary to repetitive strains. A mechanism for the development of stress fractures involves the accumulation of microdamage, which occurs with multiple subultimate failure loads applied to the bone. Stress fractures may be classified as high or low risk, depending on the grade of the injury. The most common site of injury is the lower extremity. In this article, we review the pathophysiology, etiology, diagnosis, and management of stress fractures, and present treatment guidelines for return to play.     

Factors associated with discharge during marine corps basic training

This prospective study assessed risk factors for discharge from basic training (BT) among 2,137 male Marine Corps recruits between February and April 2003. Physical and demographic characteristics, exercise, and previous lower extremity injuries before arrival at Marine Corps Recruit Depot were assessed by questionnaire during intake processing. Stress fractures were confirmed by x-ray, triple-phase bone scan, or magnetic resonance imaging. Overall, 223 (10.4%) participants were discharged from training. In addition to the occurrence of a stress fracture during BT, older age (>23 years), non-Hispanic race, poor incoming self-rated physical fitness, no history of competitive exercise, and an incoming lower extremity injury with incomplete recovery were independent risk factors for discharge. Strategies to identify and allow the proper healing time for pre-BT lower extremity injuries, including interventions to improve the physical fitness of recruits before BT and reduce stress fractures during BT, may be indicated to lower attrition.     

Stress fracture of the ulna occurring in military recruits after rifle drill training

Stress fractures are a common injury in military recruits in the lower extremities, but are rare in the upper limbs. The locations of reported stress fractures occurring in the upper extremities are mainly in the ulna and olecranon. We report on two cases of mid-ulnar stress fractures in a team of honor guards following rifle drill training from excessive weight lifting, repetitive pronation of the forearm, and a sudden increase in the training load. According to the report, some readjustment must be made in the training protocol for military recruits. Stress fractures are also being recognized as a prevalent problem in the upper body.     

Low-risk stress fractures

Stress fractures can occur in almost any bone in the body, with the lower extremity weightbearing bones, especially the tibia, tarsals, and metatarsals, being affected most frequently. Although the cause of these fractures is multifactoral, repetitive physical forces without adequate rest are the primary culprits. Stress fractures may be broadly classified as low-risk or high-risk injuries. Low-risk stress fractures, the topic of this review article, can be diagnosed through a thorough history, physical examination, and radiographs. Nuclear scintigraphy is occasionally necessary for confirmation, especially for fractures of the spine and pelvis. When diagnosed early and treated with restriction of activity, low-risk stress fractures have a favorable prognosis.     

Foot and ankle fractures in dancers

Fractures in the dance population are common. Radiography, CT, MRI, and bone scan should be used as necessary to arrive at the correct diagnosis after meticulous physical examination. Treatment should address the fracture itself and any surrounding problems such as nutritional/hormonal issues and training/performance techniques and regimens. Compliance issues in this population are a concern, so treatment strategies should be tailored accordingly. Stress fractures in particular can present difficulties to the treating physician and may require prolonged treatment periods. This article addresses stress fractures of the fibula, calcaneus, navicular, and second metatarsal; fractures of the fifth metatarsal, sesamoids, and phalanges; and dislocation of toes.     

An unusual stress fracture in a multiple sport athlete

Most overuse injuries are a direct result of repetitive stresses which may create a condition of maltraining. Young athletes are no exception to this rule. Swimming and baseball both create stresses to the humerus which may result in injuries to the shoulder and upper extremity. Stress fractures (fatigue fractures) are usually limited to the lower extremity (i.e., tibia or metatarsal). Upper extremity stress fractures, especially of the humerus, are very uncommon. Precipitating factors include repetitive stresses, low grade external forces, rapid application of muscular force to the bone, or an underlying disease or pathologic weakness of the bone. The majority of these fractures are primarily due to abnormal and repetitive stresses to bones. This case study examines the mechanism of injury, clinical presentation, and treatment of a clinically apparent stress fracture which ultimately converted to an overt humerus fracture in a 14-yr-old cross-trained athlete.     

Stress fractures in athletes

Stress fractures may pose a diagnostic dilemma for radiologists since they are sometimes difficult to demonstrate on plain films and may simulate a tumour. They were first described in military personnel and professional athletes. Recently, there is an increasing incidence in the general population due to increasing sportive activities. Stress fractures occur most often in the lower extremities, especially in the tibia, the tarsal bone, the metatarsal bone, the femur and the fibula. In the upper extremities, they are commonly found in the humerus, the radius and the ulna. Some fractures of the lower extremities appear to be specific for particular sports, for example, fractures of the tibia affect mostly distance runners. Whereas stress fractures of the upper extremities are generally associated with upper limb-dominated sports. A correct diagnosis requires a careful clinical evaluation. The initial plain radiography may be normal. Further radiological evaluation could be performed by means of computerised tomography, magnetic resonance imaging and bone scanning. The latter two techniques are especially helpful for establishing a correct initial diagnosis.     

Stress fractures of the distal tibia and calcaneus subsequent to acute fractures of the tibia and fibula

Stress fractures (two in the calcaneus and four in the distal tibia) occurring distal to the site of a healing fracture of the tibia or fibula were discovered in five patients. Three of these fractures were identified radiographically at the time of their occurrence, and three were identified only after retrospective review of the radiographs of 74 patients with previous tibial or fibular fractures. Three of the patients were less than 10 years old. All five patients had disuse osteopenia and recently had begun weight-bearing. Four patients had healing of their acute fractures with angulation or displacement. Stress fractures can easily be overlooked on radiographic studies in this setting and may be a source of pain that mistakenly can be attributed to malunion or nonunion. Stress fractures should be considered in patients with fractures of the lower extremity, particularly those who experience new or persistent pain or discomfort.     

Stress fractures: Current concepts

1. Stress fractures result from muscular activity on bones rather than from direct impact upon them. 2. The fatigue variety of stress fracture occurs in normal bone when abnormal muscular tension or torsion is placed upon it. 3. The insufficiency type of stress fracture results when normal muscular stress is placed upon a bone with deficient elastic resistance. 4. Most stress fractures are of the fatigue type, occurring in an individual who engages in repetitive vigorous activity to which he is unaccustomed. 5. The biomechanics, radiologic features, and differential diagnosis were discussed and the literature was reviewed.     

Bone stress lesions in ballet dancers: scintigraphic assessment

Ballet dancers are athletes susceptible to ligamentous and bony injury. We reviewed retrospectively the bone scans (technetium-99m methylene diphosphonate) of 23 ballet dancers with pain in the back and/or lower extremities to determine the usefulness of scintigraphy in the detection of stress lesions of bone. The scintigraphic studies in 19 dancers identified multiple areas of stress injury in both symptomatic and asymptomatic locations. Thirteen dancers had 22 stress fractures (microfractures of trabeculae with associated bone repair) manifested by an intense focus of increased uptake of radiopharmaceutical, and 19 dancers had stress reactions (areas of accelerated remodeling and resorption of bone) demonstrated by diffusely increased uptake of radiotracer. Ten of the 13 dancers with stress fractures were symptomatic and six of the 19 dancers with stress reactions were symptomatic. The radiographs of 10 dancers with positive bone scans were normal or showed no distinction between acute and chronic injuries. Stress fractures were most prevalent in the feet, and stress reactions were most prevalent in the tibiae. The study confirmed that ballet dancers sustain significant bone stress in their legs and feet. Our results show that scintigraphy can be used to detect stress fractures and stress reactions at both symptomatic and asymptomatic sites in this population.     

Clinical aspects, radiology and differential diagnosis of stress fractures

Stress fractures result from bone stress in a rhythmical, repeated and subthreshold manner. Fatigue fractures and insufficiency fractures are considered. In the present paper clinical and radiological findings in stress fractures and problems of differential diagnosis are discussed. Typical locations and forms of manifestation are presented.     

Aetiology of rib stress fractures in rowers

Rib stress fractures are a common and significant problem in the rowing population. They occur in approximately 6.1 to 12% of rowers and account for the most time lost from on-water training and competition. This review discusses possible causative factors for rib stress fractures in rowers. Central to the establishment of causative factors is the identification that each rib forms part of a closed ring of bone that is completed anteriorly by the sternum and posteriorly by the thoracic vertebrae. Because of the shared sternum anteriorly each ring of bone is mechanically connected. Subsequently, during rowing individual ribs are not loaded in isolation, rather the rib cage is loaded as a complete unit. Incorporating this functioning as a complete unit a possible mechanism by which different factors contribute to rib stress fracture can be developed. In rowing, muscle factors generate loading of the rib cage. The characteristics of this loading stimulus are influenced by equipment, technique and joint factors. Rib-cage loading generates bone strain in individual ribs with the response of each rib depending upon site-specific skeletal factors. Depending on the characteristics of the bone strain in terms of the magnitude and rate of strain, microdamage may develop. The bone response to this microdamage is reparative remodelling. Whether this response is capable of repairing the damage to prevent progression to a stress fracture is dependent upon training and gender factors. Identification of these factors will generate a better understanding of the aetiology of this injury, which is required for improved prevention and treatment strategies.