Measurement of microstructural strain in cortical bone.
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It is well known that mechanical factors affect bone remodeling such that increased mechanical demand results in net bone formation, whereas decreased demand results in net bone resorption. Current theories suggest that bone modeling and remodeling is controlled at the cellular level through signals mediated by osteocytes. The objective of this study was to investigate how macroscopically applied bone strains similar in magnitude to those that occur in vivo are manifest at the microscopic level in the bone matrix. Using a digital image correlation strain measurement technique, experimentally determined bone matrix strains around osteocyte lacuna resulting from macroscopic strains of approximately 2,000 microstrain (0.2%) reach levels of over 30,000 microstrain (3%) over fifteen times greater than the applied macroscopic strain. Strain patterns were highly heterogeneous and in some locations similar to observed microdamage around osteocyte lacuna indicating the resulting strains may represent the precursors to microdamage. This information may lead to a better understanding of how bone cells are affected by whole bone functional loading. (+info)
Fatigue injuries of the femur.
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The purpose of this study was to describe the anatomical distribution and incidence of fatigue injuries of the femur in physically-active young adults, based upon MRI studies. During a period of 70 months, 1857 patients with exercise-induced pain in the femur underwent MRI of the pelvis, hips, femora, and/or knees. Of these, 170 patients had a total of 185 fatigue injuries, giving an incidence of 199 per 100 000 person-years. Bilateral injuries occurred in 9% of patients. The three most common sites affected were the femoral neck (50%), the condylar area (24%) and the proximal shaft (18%). A fatigue reaction was seen in 57%, and a fracture line in 22%. There was a statistical correlation between the severity of the fatigue injury and the duration of pain (p = 0.001). The location of the pain was normally at the site of the fatigue injury. Fatigue injuries of the femur appear to be relatively common in physically-active patients. (+info)
Stress fractures of the femoral shaft in women's college lacrosse: a report of seven cases and a review of the literature.
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BACKGROUND: Stress fractures do not often occur in the shaft of the femur. They are more common in the femoral neck, the tibial shaft, the metatarsals, and other bones of the foot. In female athletes, stress fractures classically afflict the distance runner, the ballerina, the gymnast, and the figure skater. OBJECTIVES: To describe the clinical presentation, diagnosis, treatment, and outcome of seven college female lacrosse players with femoral shaft stress fractures, and review the literature. RESULTS: The unusual results of this study support the principle that clinical suspicion should be high when treating any female athlete regardless of the sport. In this case series, an abrupt change in the quality of the running surface during the competitive training season was the only underlying common thread among the athletes. CONCLUSION: The findings suggest that risk factors for the female athlete are variable and are no longer limited to the undernourished or overtrained. (+info)
Navicular stress fractures: outcomes of surgical and conservative management.
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OBJECTIVE: To compare the long term outcomes of the two treatment options for navicular stress fractures: non-weightbearing cast immobilisation and surgical fixation. DESIGN: Retrospective case study. PARTICIPANTS: Subjects aged 18 years and older who had been treated for a navicular stress fracture more than two years previously. MAIN OUTCOME MEASURES: Questionnaire based analogue pain score and function score; tenderness on palpation; abnormality detected on computed tomography (CT). RESULTS: In all, 32 fractures in 26 subjects were investigated. No significant differences were found between surgical and conservative management for current pain (p = 0.984), current function (p = 0.170), or abnormality on CT (p = 0.173). However, surgically treated patients more often remained tender over the "N spot" (p = 0.005), even after returning to competition for two years or more. CONCLUSIONS: Surgical fixation of navicular stress fractures appears to be as effective as conservative management over the longer term. However, there remains a small but measurable degree of pain and loss of function over this period. The value of using "N spot" tenderness as the sole clinical predictor of treatment success requires further investigation, as some patients remained tender despite successful completion of treatment and return to competition. (+info)
The incidence and distribution of stress fractures in elite tennis players.
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BACKGROUND: Modern professional tennis involves powerful movements repeatedly subjecting the musculoskeletal system to heavy mechanical load. Thus tennis players are exposed to high risk of overuse injuries including stress fractures. OBJECTIVE: To determine the incidence and distribution of stress fractures in elite tennis players. STUDY DESIGN: Retrospective cohort study. METHODS: The cohort study population consisted of 139 elite players (mean (SD) age, 20.0 (5.0) years; 48 female, 91 male). Stress fractures were identified and confirmed radiologically from medical records during a two year period. Injuries were analysed according to age, sex, site, severity, delay in diagnosis, and time needed to return to sports. RESULTS: 15 players sustained 18 stress fractures, corresponding to an overall case incidence of 12.9% (95% confidence interval (CI), 8.1 to 20.0). The tarsal navicular was most affected (n = 5; 27%), followed by the pars interarticularis (n = 3; 16%), the metatarsals (n = 3; 16%), the tibia (n = 2; 11%) and the lunate (n = 2; 11%). Magnetic resonance imaging showed a greater incidence of "high grade" lesions (94.4%). Stress fracture incidence was significantly higher in juniors (20.3% (95% CI, 11.4 to 33.2)) than in professional players (7.5% (2.8 to 15.6)) (p = 0.045). CONCLUSIONS: There was a high absolute risk (12.9%) of stress fractures in elite tennis players over a two year period. Junior players were at highest risk. The lesions are a major cause of disruption both of training and of competition. Risk factors should therefore be identified and prevention emphasised. (+info)
Sacral stress fracture: an unusual cause of low back pain in an amateur tennis player.
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Stress fractures are common in athletes, and their incidence in sport is estimated at 2-4%. A case is reported of a stress fracture of the sacrum in an amateur tennis player. The patient was treated with rest and physiotherapy, focusing on stretching programmes and analgesic treatments, followed by an educational programme of tennis training and muscle strengthening. This appears to be the first report of this pathology in a tennis player. (+info)
Stress fractures of the femoral shaft in athletes: a new treatment algorithm.
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BACKGROUND: Femoral shaft stress fractures in athletes are not common but pose a great diagnostic challenge to clinicians. Because of few clinical signs, diagnosis and treatment are often delayed. Furthermore, if not treated correctly, these fractures are well known for complications and difficulties. OBJECTIVE: To develop a well structured and reproducible treatment algorithm for athletes with femoral shaft stress fractures. METHODS: The proposed algorithm is carried out in four phases, each lasting three weeks, and the move to the next phase is based on the result of the tests carried out at the end of the previous phase. Over nine years, we treated seven top level athletes, aged 17-21. In all athletes, diagnosis was based on physical examination, plain radiographs, and bone scan. RESULTS: As a result of the treatment method, all the athletes were fully engaged in athletic activity 12-18 weeks after the beginning of treatment. After completion of the treatment, the athletes were followed up for 48-96 months. During the follow up, there was no recurrence of discomfort or pain, and all the athletes eventually returned to competition level. CONCLUSION: These results and data available from the literature suggest that the algorithm is the optimal treatment protocol for femoral shaft stress fractures in athletes, avoiding the common complications and difficulties. (+info)
Stress fracture of the clavicle in a patient with no obvious risk factors.
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A 28-year-old woman presented with right shoulder pain and, after a delay, a diagnosis of clavicular stress fracture was made. The patient gave no history of repetitive abnormal loading of the upper limbs which could have assisted the diagnosis. The authors wish to raise awareness of this rare diagnosis such that it can be considered in the differential for shoulder pain of unclear origin. (+info)