The role of the bronchial provocation challenge tests in the diagnosis of exercise-induced bronchoconstriction in elite swimmers.

BACKGROUND: The International Olympic Committee-Medical Commission (IOC-MC) accepts a number of bronchial provocation tests for the diagnosis of exercise-induced bronchoconstriction (EIB) in elite athletes, none of which have been studied in elite swimmers. With the suggestion of a different pathogenesis involved in the development of EIB in swimmers, there is a possibility that the recommended test for EIB in elite athletes, the eucapnic voluntary hyperpnoea (EVH) challenge, may be missing the diagnosis in elite swimmers. OBJECTIVE: The aim of this study was to assess the effectiveness of the EVH challenge, the field swim challenge and the laboratory cycle challenge in the diagnosis of EIB in elite swimmers. DESIGN: 33 elite swimmers were evaluated on separate days for the presence of EIB using 3 different bronchial provocation challenge tests: an 8 minute field swim challenge, a 6 minute laboratory EVH challenge, and an 8 minute laboratory cycle challenge. MAIN OUTCOME MEASUREMENTS: Change in forced expiratory volume in 1 second (FEV(1)) pre and post test protocol. A fall in FEV(1) from baseline of > or =10% post challenge was diagnostic of EIB. RESULTS: Only 1 of the 33 subjects (3%) had a positive field swim challenge with a fall in FEV(1) of 16% from baseline. 18 of the 33 subjects (55%) had a positive EVH challenge, with a mean fall in FEV(1) of 20.4 (SD 11.7)% from baseline. 4 of the subjects (12%) had a positive laboratory cycle challenge, with a mean fall in FEV(1) of 14.8 (4.7)% from baseline. Only 1 of the 33 subjects was positive to all 3 challenges. CONCLUSIONS: These results suggest that the EVH challenge is a highly sensitive challenge for identifying EIB in elite swimmers, in contrast to the laboratory and field-based exercise challenge tests, which significantly underdiagnose the condition. The EVH challenge, a well-established and standardised test for EIB in elite winter and summer land-based athletes, should thus be used for the diagnosis of EIB in elite swimmers, as recommended by the IOC-MC.

Use of the one-legged hyperextension test and magnetic resonance imaging in the diagnosis of active spondylolysis.

BACKGROUND: Active spondylolysis is an acquired lesion in the pars interarticularis and is a common cause of low back pain in the young athlete. OBJECTIVES: To evaluate whether the one-legged hyperextension test can assist in the clinical detection of active spondylolysis and to determine whether magnetic resonance imaging (MRI) is equivalent to the clinical gold standard of bone scintigraphy and computed tomography in the radiological diagnosis of this condition. METHODS: A prospective cohort design was used. Young active subjects with low back pain were recruited. Outcome measures included clinical assessment (one-legged hyperextension test) and radiological investigations including bone scintigraphy (with single photon emission computed tomography (SPECT)) and MRI. Computed tomography was performed if bone scintigraphy was positive. RESULTS: Seventy one subjects were recruited. Fifty pars interarticulares in 39 subjects (55%) had evidence of active spondylolysis as defined by bone scintigraphy (with SPECT). Of these, 19 pars interarticulares in 14 subjects showed a fracture on computed tomography. The one-legged hyperextension test was neither sensitive nor specific for the detection of active spondylolysis. MRI revealed bone stress in 40 of the 50 pars interarticulares in which it was detected by bone scintigraphy (with SPECT), indicating reduced sensitivity in detecting bone stress compared with bone scintigraphy (p = 0.001). Conversely, MRI revealed 18 of the 19 pars interarticularis fractures detected by computed tomography, indicating concordance between imaging modalities (p = 0.345). There was a significant difference between MRI and the combination of bone scintigraphy (with SPECT)/computed tomography in the radiological visualisation of active spondylolysis (p = 0.002). CONCLUSIONS: These results suggest that there is a high rate of active spondylolysis in active athletes with low back pain. The one-legged hyperextension test is not useful in detecting active spondylolysis and should not be relied on to exclude the diagnosis. MRI is inferior to bone scintigraphy (with SPECT)/computed tomography. Bone scintigraphy (with SPECT) should remain the first-line investigation of active athletes with low back pain followed by limited computed tomography if bone scintigraphy is positive.

Navicular stress fractures: outcomes of surgical and conservative management.

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.

Effect of dry needling of gluteal muscles on straight leg raise: a randomised, placebo controlled, double blind trial.

OBJECTIVES: To use a randomised, double blind, placebo controlled trial to establish the effect on straight leg raise, hip internal rotation, and muscle pain of dry needling treatment to the gluteal muscles in athletes with posterior thigh pain referred from gluteal trigger points. METHODS: A randomised, double blind, placebo controlled trial of 59 male runners was performed during the 2002 Australian Rules football season. Subjects were thoroughly screened and had magnetic resonance imaging of their hamstring muscles to exclude local pathology. The inclusion criterion was reproduction of recognisable posterior thigh pain with the application of digital pressure to the gluteal trigger points. Subjects randomly received either therapeutic or placebo needle treatment on one occasion at their gluteal trigger points. Range of motion and visual analogue scale data were collected immediately before, immediately after, 24 hours after, and 72 hours after the intervention. Range of motion was measured with passive straight leg raise and hip internal rotation. Visual analogue scales were completed for hamstring and gluteal pain and tightness at rest and during a running task. RESULTS: Magnetic resonance imaging scans revealed normal hamstring musculature in most subjects. Straight leg raise and hip internal rotation remained unchanged in both groups at all times. Visual analogue scale assessment of hamstring pain and tightness and gluteal tightness after running showed improvements immediately after the intervention in both groups (p = 0.001), which were maintained at 24 and 72 hours. The magnitude of this improvement was the same for therapeutic and placebo interventions. Resting muscle pain and tightness were unaffected. CONCLUSIONS: Neither dry needling nor placebo needling of the gluteal muscles resulted in any change in straight leg raise or hip internal rotation. Both interventions resulted in subjective improvement in activity related muscle pain and tightness. Despite being commonly used clinical tests in this situation, straight leg raise and hip internal rotation are not likely to help the therapist assess response to treatment. Patient reports of response to such treatment are better indicators of its success. The mechanisms by which these responses occur and the reasons for the success of the placebo needling treatment are areas for further investigation.

Bone mass and bone turnover in power athletes, endurance athletes, and controls: a 12-month longitudinal study.

Strain magnitude may be more important than the number of loading cycles in controlling bone adaptation to loading. To test this hypothesis, we performed a 12 month longitudinal cohort study comparing bone mass and bone turnover in elite and subelite track and field athletes and less active controls. The cohort comprised 50 power athletes (sprinters, jumpers, hurdlers, multievent athletes; 23 women, 27 men), 61 endurance athletes (middle-distance runners, distance runners; 30 women, 31 men), and 55 nonathlete controls (28 women, 27 men) aged 17-26 years. Total bone mineral content (BMC), regional bone mineral density (BMD), and soft tissue composition were measured by dual-energy X-ray absorptiometry. Bone turnover was assessed by serum osteocalcin (human immunoradiometric assay) indicative of bone formation, and urinary pyridinium crosslinks (high-performance liquid chromatography) indicative of bone resorption. Questionnaires quantified menstrual, dietary and physical activity characteristics. Baseline results showed that power athletes had higher regional BMD at lower limb, lumbar spine, and upper limb sites compared with controls (p < 0.05). Endurance athletes had higher BMD than controls in lower limb sites only (p < 0.05). Maximal differences in BMD between athletes and controls were noted at sites loaded by exercise. Male and female power athletes had greater bone density at the lumbar spine than endurance athletes. Over the 12 months, both athletes and controls showed modest but significant increases in total body BMC and femur BMD (p < 0.001). Changes in bone density were independent of exercise status except at the lumbar spine. At this site, power athletes gained significantly more bone density than the other groups. Levels of bone formation were not elevated in athletes and levels of bone turnover were not predictive of subsequent changes in bone mass. Our results provide further support for the concept that bone response to mechanical loading depends upon the bone site and the mode of exercise.

Stress fractures of the upper limb.

Stress fractures are commonly found in the lower limb, but also occur in the upper limb, and are particularly associated with upper limb-dominated sports such as tennis and swimming and those involving throwing activities. Stress fractures of the clavicle and scapula are rare but have been reported, whereas those of the humerus are more frequent and have been described mainly in adolescent baseball pitchers. Olecranon stress fractures occur in throwers and gymnasts. Stress fractures of the ulna and radius have also been reported in a number of different upper limb-dominated sports. In all cases, these fractures heal with conservative management. The physician should consider stress fracture as a possible diagnosis in cases of upper limb pain of bony origin where the pain is associated with overuse.

Stress fractures in female athletes. Diagnosis, management and rehabilitation.

Stress fractures are a common overuse injury among athletes. The incidence of stress fractures among females is higher in the military, but this difference is not as evident in the athletic population. The history of the patient with stress fracture is typically one of insidious onset of activity-related pain. If the patient continues to exercise, the pain may well become more severe or occur at an earlier stage of exercise. As well as obtaining a history of the patient's pain and its relation to exercise, it is important to determine the presence of predisposing factors. On physical examination, the most obvious feature is localised bony tenderness. Occasionally, redness, swelling or periosteal thickening may be present at the site of the stress fracture. The diagnosis of stress fracture is primarily a clinical one; however, if the diagnosis is uncertain, various imaging techniques can be used to confirm the diagnosis. In the majority of stress fractures, there is no obvious abnormality on plain radiograph. Although the triple phase bone radiograph is extremely sensitive, the fracture itself is not visualised and it may be difficult to precisely locate the site, especially in the foot. The radionuclide scan will detect evolving stress fractures at the stage of accelerated remodelling, so the findings must be closely correlated with the clinical picture. The characteristic bone scan appearance of a stress fracture is of a sharply marginated area of increased uptake, usually involving one cortex of the bone. Computerised tomography scanning is a helpful addition if the fracture needs to be visualised, or to distinguish between a stress reaction and stress fracture. Magnetic resonance imaging (MRI) is being used increasingly as the investigation of choice for stress fractures. The typical findings on MRI are of periosteal and marrow oedema, as well as fracture line. The basis of treatment of a stress fracture involves rest from the aggravating activity. Most stress fractures will heal in a straightforward manner, and return to sport occurs within 6 to 8 weeks. The rate of resumption of activity should be influenced by symptoms and physical findings. When free of pain, the aggravating activity can be resumed and slowly increased. It is important that the athlete with a stress fracture maintain fitness during this period of rehabilitation. The most commonly used methods are cycling, swimming, upper body weights and water running. There are a number of specific stress fractures that require additional treatment because of a tendency to develop delayed union or nonunion. These include stress fractures of the neck of the femur, anterior cortex of the tibia, navicular and second and fifth metatarsals. An essential component of the management of stress fractures, as with any overuse injury, involves identification of the factors that have contributed to the injury and, where possible, correction or modification of some of these factors to reduce the risk of the injury recurring. Stress fractures are more common in female athletes with menstrual disturbances. This may be due to the effect on bone density. The role of hormonal replacement in the management of these athletes is unclear at this stage.

Risk factors for stress fractures.

Preventing stress fractures requires knowledge of the risk factors that predispose to this injury. The aetiology of stress fractures is multifactorial, but methodological limitations and expediency often lead to research study designs that evaluate individual risk factors. Intrinsic risk factors include mechanical factors such as bone density, skeletal alignment and body size and composition, physiological factors such as bone turnover rate, flexibility, and muscular strength and endurance, as well as hormonal and nutritional factors. Extrinsic risk factors include mechanical factors such as surface, footwear and external loading as well as physical training parameters. Psychological traits may also play a role in increasing stress fracture risk. Equally important to these types of analyses of individual risk factors is the integration of information to produce a composite picture of risk. The purpose of this paper is to critically appraise the existing literature by evaluating study design and quality, in order to provide a current synopsis of the known scientific information related to stress fracture risk factors. The literature is not fully complete with well conducted studies on this topic, but a great deal of information has accumulated over the past 20 years. Although stress fractures result from repeated loading, the exact contribution of training factors (volume, intensity, surface) has not been clearly established. From what we do know, menstrual disturbances, caloric restriction, lower bone density, muscle weakness and leg length differences are risk factors for stress fracture. Other time-honoured risk factors such as lower extremity alignment have not been shown to be causative even though anecdotal evidence indicates they are likely to play an important role in stress fracture pathogenesis.

Tarsal navicular stress fracture in athletes.

Stress fracture of the tarsal navicular bone is now frequently recognised. The majority of navicular stress fractures are partial fractures in the sagittal plane. They occur mainly in track and field athletes. A number of theories regarding the aetiology of this fracture have been proposed. Athletes with a history of vague, activity-related midfoot pain, with associated tenderness over the dorsal proximal navicular ('N' spot) should be suspected of having a navicular stress fracture. Plain radiography frequently fails to demonstrate the fracture, thus radionuclide scanning is the investigation of choice to detect navicular stress injury. A computed tomography (CT) scan should be performed to confirm the presence of the fracture. Various methods of treatment have been employed. A minimum of 6 weeks of strict non-weightbearing cast immobilisation is the treatment of choice. After removal of the cast, a further 6 week programme of rehabilitation with a graduated return to activity, joint mobilisation and soft tissue massage is required. Surgery for nonunion or delayed union is rarely required if initial treatment is appropriate.

Obturator nerve entrapment. A cause of groin pain in athletes.

Chronic groin pain in athletes is often difficult to diagnose and treat. There are many anatomic structures in the inguinal and groin region that have the potential to cause pain. We report 32 cases of a previously undescribed condition in athletes of "obturator neuropathy," a fascial entrapment of the obturator nerve where it enters the thigh. This condition represents a type of groin pain in athletes that is treatable by surgical means. There is a characteristic clinical pattern of exercise-induced medial thigh pain commencing in the region of the adductor muscle origin and radiating distally along the medial thigh. Needle electromyography demonstrates denervation of the adductor muscles. Surgical neurolysis treatment provides the definitive cure of this problem, with athletes returning to competition within several weeks of treatment. The surgical findings are entrapment of the obturator nerve by a thick fascia overlying the short adductor muscle. The role of conservative treatment in the management of this condition is unknown at present.

Outcome of conservative and surgical management of navicular stress fracture in athletes. Eighty-six cases proven with computerized tomography.

Eighty-two athletes with 86 clinical navicular stress fractures, all imaged with computerized tomography, were followed for an average of 33 months (range, 6 to 108) after diagnosis. Initial treatment consisted of at least 6 weeks of nonweightbearing cast immobilization for 22 fractures, at least 6 weeks of limitation of activity with continued weightbearing for 34 fractures, and a period of less than 6 weeks of conservative treatment for another 19 fractures. Five patients attempted to continue playing sports. Six patients had immediate surgery. Nineteen of 22 patients (86%) who had initial non-weightbearing cast immobilization treatment returned to sports, compared with only 9 of 34 patients (26%) who initially continued weightbearing with limited activity (P < 0.001). After failure of the latter treatment, successful outcomes were seen for 6 of 7 patients (86%) treated with nonweightbearing cast immobilization, while 11 of 15 patients (73%) who had one surgical procedure were able to return to sports. These results indicate that nonweightbearing cast immobilization is the treatment of choice for navicular stress fractures. Also, this treatment compares favorably with surgical treatment for patients who present after failed weightbearing treatments. Computerized tomographic appearances of healing fractures do not necessarily mirror clinical union, and postimmobilization management should be monitored clinically.

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.

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.

Histology of the fascial-periosteal interface in lower limb chronic deep posterior compartment syndrome.

OBJECTIVE: To describe the histological features of the fascial-periosteal interface at the medial tibial border of patients surgically treated for chronic deep posterior compartment syndrome and to make statistical comparisons with control tissue. METHODS: Nineteen subjects and 11 controls were recruited. Subject tissue was obtained at operation, and control tissue from autopsy cases. Tissue samples underwent histological preparation and then examination by an independent pathologist. Samples were analysed with regard to six histological variables: fibroblastic activity, chronic inflammatory cells, vascularity, collagen regularity, mononuclear cells, and ground substance. Collagen regularity was measured with respect to collagen density, fibre arrangement, orientation, and spacing. The observed changes were graded from 1 to 4 in terms of abnormality. Mann-Whitney U test, Spearman correlation coefficients, and intraobserver reliability scores were used. RESULTS: With regard to collagen arrangement, control tissue showed greater degrees of irregularity than subject tissue (p = 0.01). Subjects with a symptom duration of greater than 12 months (as opposed to less than 12 months) showed greater degrees of collagen irregularity (p = 0.043). Vascular changes approached significance (p = 0.077). With regard to the amount of fibrocyte activity, chronic inflammatory cell activity, mononuclear cells, or ground substance, there were no significant differences between controls and subjects. Good correlation was seen in scores measuring chronic inflammatory cell activity and mononuclear cells (r = 0.649), and moderate correlation was seen between fibrocyte activity and vascular changes (r = 0.574). Intraobserver reliability scores were good for chronic inflammatory cell activity and moderate for vascular changes, but were poor for collagen and fibrocyte variables. Individual cases showed varying degrees of fibrocyte activity, chronic inflammatory cellular infiltration, vascular abnormalities, and collagen fibre disruption. CONCLUSIONS: Statistical analysis showed no histological differences at the fascial-periosteal interface in cases of chronic deep posterior compartment syndrome, except for collagen, which showed less irregularity in subject samples. The latter may indicate a remodelling process, and this is supported by greater collagen irregularity in subjects with longer duration of symptoms.

Epidemiology and site specificity of stress fractures.

Clinically, stress fractures appear to be a common overuse injury among athletes and in military recruits undertaking basic training; however, there is a lack of sound epidemiologic studies describing stress fracture occurrence in athletes. Few have directly compared stress fracture rates between sports to establish which poses the greatest risk for this injury. Furthermore, incidence rates, expressed in terms of exposure, have rarely been reported for stress fractures in athletes. Nevertheless, available data suggest that runners and ballet dancers are at relatively high risk for stress fractures. Although a gender difference in rates is clearly evident in military populations, this is less apparent in athletes. Other participant characteristics, such as age and race, may also influence stress fracture risk. The most common site of stress fracture in athletes is the tibia, although the site reflects the nature of the load applied to the skeleton. Stress fracture morbidity, expressed as the time until return to sport or activity, varies depending on the site. Generally, a period of 6 to 8 weeks is needed for healing; however, stress fractures at certain sites, such as the navicular and anterior tibial cortex, are often associated with protracted recovery and, in some cases, termination of sporting pursuits.

Sports medicine. Overuse injuries. Part 1: bone.

Musculoskeletal problems have always been a large part of the general practitioner's case load. The development of sports medicine as a separate entity has helped define and increase understanding of these problems, many of which are managed in a general practice environment. This monthly series is designed to improve and update knowledge in this area and provide useful pointers for management.

Calf and ankle swelling.

BACKGROUND: Swelling of the calf and ankle region is a common presenting symptom and historical features such as speed of onset, trauma and mechanism of injury are important in aiding diagnosis. OBJECTIVE: To discuss diagnosis and management of musculoskeletal causes of calf and ankle swelling. DISCUSSION: Calf muscle injuries and injuries around the ankle including Achilles tendon injuries, ankle ligament injuries and overuse injuries are discussed.

The difficult ankle.

Ankle sprains are extremely common in sport and usually respond to conservative management, but many apparent ankle sprains do not respond to treatment and remain painful. Alternative diagnoses must be considered. These require careful clinical assessment and often further investigations.

Managing common stress fractures: let risk level guide treatment.

The repetitive stresses of sports and exercise can produce an array of stress fractures. Most are uncomplicated, but some, such as femoral neck fractures, carry a higher risk of nonunion or complete fracture. The diagnosis is primarily clinical, but imaging with plain radiographs, scintigraphy, CT, or MRI may provide confirmation if necessary. Treatment of uncomplicated fractures centers on rest and reversing training errors or equipment problems. Management of high-risk fractures is more aggressive. Depending on imaging results, most of these require either surgery or several weeks of non-weight bearing immobilization and rehabilitation.

Obturator neuropathy: a cause of exercise-related groin pain.

Obturator neuropathy is a cause of exercise-related groin pain, particularly in those who play sports that involve much running, twisting and turning, and kicking. Symptoms include pain that begins insidiously at the adductor origin on the pubic bone and worsens with exercise. Diagnostic measures include reproduction of pain by stretching the pectineus muscle after exercise, electromyography, and a local anesthetic block of the obturator nerve. Surgery allows most patients to resume previous levels of activity.