Negative bone scans in impending tibial stress fractures. A report of three cases

Stress fracture of the lateral cuneiform bone: a case report

Stress fractures are common overuse injuries of the bone that are most often seen in athletes and military personnel. These types of injuries seem to be commonly missed or delayed in diagnosis. Physicians should consider the possibility of such an injury while determining the diagnosis of a long-lasting foot pain. The aim of this paper was to report an isolated stress fracture of the lateral cuneiform bone. A review of the literature failed to find a similar case.

Tibial stress injury: relationship of radiographic, nuclear medicine bone scanning, MR imaging, and CT Severity grades to clinical severity and time to healing

PURPOSE

To examine the relationship between severity grade for radiography, triple-phase technetium 99m nuclear medicine bone scanning, magnetic resonance (MR) imaging, and computed tomography (CT); clinical severity; and recovery time from a tibial stress injury (TSI), as well as to evaluate interassessor grading reliability.

MATERIALS AND METHODS

This protocol was approved by the Griffith University Human Research Ethics Committee, the Stanford University Panel on Human Subjects in Medical Research, the U.S. Army Human Subjects Research Review Board, and the Australian Defense Human Research Ethics Committee. Informed consent was obtained from all subjects. Forty subjects (17 men, 23 women; mean age, 26.2 years ± 6.9 [standard deviation]) with TSI were enrolled. Subjects were examined acutely with standard anteroposterior and lateral radiography, nuclear medicine scanning, MR imaging, and CT. Each modality was graded by four blinded clinicians. Mixed-effects models were used to examine associations between image severity, clinical severity, and time to healing, with adjustments for image modality and assessor. Grading reliability was evaluated with the Cronbach α coefficient.

RESULTS

Image assessment reliability was high for all grading systems except radiography, which was moderate (α = 0.565-0.895). Clinical severity was negatively associated with MR imaging severity (P ≤ .001). There was no significant relationship between time to healing and severity score for any imaging modality, although a positive trend existed for MR imaging (P = .07).

CONCLUSION

TSI clinical severity was negatively related to MR imaging severity. Radiographic, bone scan, and CT severity were not related to time to healing, but there was a positive trend for MR imaging.

Ultrasound as a primary evaluation tool of bone stress injuries in elite track and field athletes

BACKGROUND

Little is known about therapeutic ultrasound (TUS) to diagnose bone stress injuries.

HYPOTHESIS

Therapeutic ultrasound is an accurate, cost-efficient alternative to other imaging methods for primary assessment of bone stress injuries.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

One hundred thirteen elite track and field athletes (mean age, 20.1 years; range, 17-28 years) underwent TUS and magnetic resonance imaging (MRI) for clinical suspicion of a bone stress injury. A 5-stage MRI grading system was used to classify bone stress injuries. Sensitivity, specificity, accuracy, and positive and negative predictive values of TUS were calculated using MRI as the standard for diagnosis.

RESULTS

At MRI, of 113 assessed patients, 3 (2.7%) had grade 0 injuries, 12 (10.6%) had grade 1, 15 (13.3%) had grade 2, 77 (68.2%) had grade 3, and 6 (5.3%) had grade 4. At TUS, no injury was detected in 22 of 113 patients: 2 with grade 0 injury, 8 with grade 1, 8 with grade 2, and 4 with grade 3. Using MRI as the gold standard, TUS showed 81.8% sensitivity, 66.6% specificity, 99.0% positive predictive value, 13.4% negative predictive value, and 81.4% accuracy.

CONCLUSION

Therapeutic ultrasound is a reproducible procedure that is reliable to diagnose bone stress injuries.

Sensitivity and specificity of ultrasonography in early diagnosis of metatarsal bone stress fractures: a pilot study of 37 patients

OBJECTIVE

To date, early diagnosis of stress fractures depends on magnetic resonance imaging (MRI) or bone scan scintigraphy, as radiographs are usually normal at onset of symptoms. These examinations are expensive or invasive, time-consuming, and poorly accessible. A recent report has shown the ability of ultrasonography (US) to detect early stress fractures. Our objective was to evaluate sensitivity and specificity of US versus dedicated MRI (0.2 Tesla), taken as the gold standard, in early diagnosis of metatarsal bone stress fractures.

METHODS

A case-control study from November 2006 to December 2007 was performed. All consecutive patients with mechanical pain and swelling of the metatarsal region for less than 3 months and with normal radiographs were included. US and dedicated MRI examinations of the metatarsal bones were performed the same day by experienced rheumatologists with expertise in US and MRI. Reading was undertaken blind to the clinical assessment and MRI/US results.

RESULTS

Forty-one feet were analyzed on US and dedicated MRI from 37 patients (28 women, 9 men, mean age 52.7 +/- 14.1 yrs). MRI detected 13 fractures in 12 patients. Sensitivity of US was 83%, specificity 76%, positive predictive value 59%, and negative predictive value 92%. Positive likehood ratio was 3.45, negative likehood ratio 0.22.

CONCLUSION

In cases of normal radiographs, US is indicated in the diagnosis of metatarsal bone stress fractures, as it is a low cost, noninvasive, rapid, and easy technique with good sensitivity and specificity. From these data, we propose a new imaging algorithm including US.

Significance of radiographic abnormalities in patients with tibial stress injuries: correlation with magnetic resonance imaging

OBJECTIVE

The objective was to correlate radiographic findings with magnetic resonance imaging (MRI) findings in patients with suspected tibial stress injuries in order to determine the significance of radiographic signs of stress injury in these individuals.

PATIENTS AND METHODS

The study group consisted of 80 patients with suspected tibial stress injuries who underwent a radiographic and MR examination of the tibia. Nineteen patients had bilateral involvement. Thus, a total of 99 tibias were evaluated. All radiographs and MR examinations were retrospectively reviewed, 1 month apart, in consensus by two musculoskeletal radiologists. The radiographs were reviewed without knowledge of the site of the clinical symptoms. Fisher's exact tests were used to determine the association between a positive radiograph and the presence of various MRI signs of a high-grade stress injury.

RESULTS

There was a strong association between the presence of periosteal reaction on radiographs at the site of the clinical symptoms and a Fredericson grade 4 stress injury on MRI.

CONCLUSIONS

The presence of periosteal reaction on radiographs at the site of clinical symptoms is predictive of a high-grade stress injury by MRI criteria.

Stress fractures in athletes

A stress fracture is a partial or complete bone fracture that results from repeated application of stress lower than the stress required to fracture the bone in a single loading. Otherwise healthy athletes, especially runners, sustain stress injuries or fractures. Prevention or early intervention is the preferable treatment. However, it is difficult to predict injury because runners vary with regard to biomechanical predisposition, training methods, and other factors such as diet, muscle strength, and flexibility. Stress fractures account for 0.7% to 20% of all sports medicine clinic injuries. Track-and-field athletes have the highest incidence of stress fractures compared with other athletes. Stress fractures of the tibia, metatarsals, and fibula are the most frequently reported sites. The sites of stress fractures vary from sport to sport (eg, among track athletes, stress fractures of the navicular, tibia, and metatarsal are common; in distance runners, it is the tibia and fibula; in dancers, the metatarsals). In the military, the calcaneus and metatarsals were the most commonly cited injuries, especially in new recruits, owing to the sudden increase in running and marching without adequate preparation. However, newer studies from the military show the incidence and distribution of stress fractures to be similar to those found in sports clinics. Fractures of the upper extremities are relatively rare, although most studies have focused only on lower-extremity injuries. The ulna is the upper-extremity bone injured most frequently. Imaging plays a key role in the diagnosis and management of stress injuries. Plain radiography is useful when positive, but generally has low sensitivity. Radionuclide bone scanning is highly sensitive, but lacks specificity and the ability to directly visualize fracture lines. In this article, we focus on magnetic resonance imaging, which provides highly sensitive and specific evaluation for bone marrow edema, periosteal reaction as well as detection of subtle fracture lines.

16-Detector multislice CT in the detection of stress fractures: a comparison with skeletal scintigraphy

AIMS

To test the hypothesis that the improved resolution afforded by 16-detector computed tomography (CT) would translate to better stress fracture detection when compared with skeletal scintigraphy.

MATERIALS AND METHODS

Thirty-three cases of suspected stress fractures in 26 patients were investigated using skeletal scintigraphy and 16-detector CT performed on the same day. Planar images of the lower limbs were taken 3h post-injection of 400MBq (99m)Tc-methylene diphosphonate ((99m)Tc-MDP). (99m)Tc-MDP uptake was quantified at suspected fracture sites. CT was performed using a 16-detector multisection machine employing 0.75mm detectors and images reconstructed in 0.5mm increments. Examinations were reported independently and discordant results were compared at follow-up.

RESULTS

At initial reporting scintigraphy identified fractures in 13 of the 33 cases and CT identified four of the 33. In one case, on review of the CT images, a fracture was present in the distal fibula that was not initially identified. This resulted in eight scintigraphic-positive CT-negative discordant cases. The (99m)Tc-MDP uptake was significantly lower in the discordant fracture group compared with the concordant group (p<0.01).

CONCLUSIONS

Despite technological advances in CT, scintigraphy appeared to detect more stress fractures. As such, multidetector CT should not be used as a routine initial investigation in stress fracture detection. The potential use of (99m)Tc-MDP quantification at fracture sites is of interest and may be worth further investigation.

Chronic anterior midtibial stress fractures in athletes treated with reamed intramedullary nailing

BACKGROUND

A chronic anterior midtibial stress fracture is a serious, difficult-to-treat injury that can adversely affect an athlete's career.

HYPOTHESIS

The use of a reamed intramedullary nail for a chronic anterior tibial stress fracture is a safe and effective treatment for an athlete.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Seven collegiate-level athletes with 11 chronic anterior midtibial stress fractures were treated with reamed intramedullary nailing between 1997 and 2000. These patients were followed for a mean duration of 17 months.

RESULTS

The mean age of the patients at the time of stress fracture diagnosis was 17 years. Seven of the fractures occurred in male athletes, whereas 4 occurred in female athletes. All patients had failed nonoperative treatment, including rest, activity modification, use of an orthosis, and low-intensity ultrasound stimulation, for a minimum of 4 months. Patients had experienced symptoms for a mean duration of 12 months. Clinical and radiological union occurred at a mean of 2.7 and 3 months, respectively. The mean duration for return to sports after surgery was 4 months. At last follow-up, all patients had full range of motion at the knee and ankle joints and were satisfied with the results. One patient developed bursitis at the tibial nail insertion site that was resolved with a steroid injection. Another patient sustained a traumatic fracture of the distal tibia 1 year after intramedullary nailing of the tibial stress fracture. This fracture healed with nonoperative treatment. No other complications were observed.

CONCLUSION

Intramedullary nailing of the tibia for chronic stress fracture has a high union rate, allows for a low complication rate, and allows for an early return to competitive sports. This procedure is an excellent alternative treatment for those fractures that have failed nonsurgical treatment.

CT and MR imaging findings in athletes with early tibial stress injuries: comparison with bone scintigraphy findings and emphasis on cortical abnormalities

PURPOSE

To prospectively compare computed tomography (CT), magnetic resonance (MR) imaging, and bone scintigraphy in athletes with clinically suspected early stress injury of tibia.

MATERIALS AND METHODS

Medical ethics committee approval and informed consent were obtained. A total of 42 patients experiencing tibial pain due to early stress injuries were evaluated. Eight patients had bilateral involvement; thus, 50 tibiae were evaluated. All patients underwent initial radiography that was negative for injury. MR imaging, CT, and bone scintigraphy were performed in all patients within 1 month of onset of symptoms. Ten asymptomatic volunteers served as the control group. Location of stress injuries, types of bone alterations, and presence of periosteal and bone marrow edema were evaluated. Sensitivity, specificity, accuracy, and positive and negative predictive values of MR imaging and CT were assessed, as was sensitivity of bone scintigraphy. McNemar test was used to detect statistically significant differences.

RESULTS

Sensitivity of MR imaging, CT, and bone scintigraphy was 88%, 42%, and 74%, respectively. Specificity, accuracy, and positive and negative predictive values were 100%, 90%, 100%, and 62%, respectively, for MR imaging and 100%, 52%, 100%, and 26%, respectively, for CT. Significant difference in detection of early tibial stress injuries was found between MR imaging and both CT and bone scintigraphy (McNemar test; P < .001 and P = .008, respectively).

CONCLUSION

MR imaging is the single best technique in assessment of patients with suspected tibial stress injuries; in some patients with negative MR imaging findings, CT can depict osteopenia, which is the earliest finding of fatigue cortical bone injury.

Imaging of stress fractures in the athlete

Osseous stress fractures and stress reactions represent the effect of abnormal repetitive stress on normal bone. An accurate and thorough clinical history and sequential radiographs often suffice 40 make the diagnosis especially when the fracture occurs in one of the common locations, such as the tibia, metatarsals, or calcaneus. In cases that are atypical in location or clinical presentation the authors rely more on MR imaging, radionuclide bone scanning, and occasionally CT. MR imaging detects early changes of osseous stress injury and allows precise definition of anatomy and extent of injury, and is the preferred modality for evaluating the continuum of osseous manifestations of stress injury. MR imaging is useful in evaluating shin splints, early osseous stress injuries, and overt stress fracture. In the elite athlete prompt diagnosis and early rehabilitation are the goals.

Comparison of scintigraphy and magnetic resonance imaging for stress injuries of bone

OBJECTIVE

To compare findings of radiography, scintigraphy, and magnetic resonance imaging (MRI) in stress injuries of bone and evaluate changes of these findings with time correlated with clinical symptoms.

DESIGN

Prospective study.

SETTING

A primary care hospital outpatient orthopedic clinic.

PATIENTS

All 31 patients with stress injuries of bone who visited our clinic from July 1996 to June 2000.

INTERVENTION

Radiography, scintigraphy, MRI, and clinical examinations were performed on the same day or at least within 1 week of each other, and the findings were compared. If symptoms of stress injury of bone continued, these examinations were repeated at intervals of 2 months until symptoms disappeared. These radiologic findings were assessed by an independent radiologist who was blinded to the clinical symptoms of the patients.

MAIN OUTCOME MEASURES

Correlation accuracy of MRI and scintigraphy findings with clinical symptoms.

RESULTS

Even with negative initial radiographic findings, all initial scintigraphy and MRI indicated stress injury of bone. There were no patients with positive/negative examinations. Grade of scintigraphy and MRI were closely correlated, and these findings also correlated with the degree of clinical symptoms. Compared with scintigraphy, MRI showed more diagnostic information, such as fracture line and periosteal edema. Areas of increased activity in scintigraphy were consistent with the grades of MRI, especially high signal intensity areas of STIR (short tau inversion recovery) image.

CONCLUSIONS

From these observations, MRI is less invasive, provides more information than scintigraphy, and is recommended for initial diagnosis and assessment stages of stress injury of bone.

Management of rowers with rib stress fractures

Stress fractures of the ribs in rowers occur mostly along the anterior axillary line, but also anteriorly and posteriorly. Management has previously consisted of rest, but symptoms can recur on return to training. Earlier return to rowing can be achieved with management that includes ice and TENS for pain relief, pulsed magnetic field therapy and passive mobilisation of the thoracic spine and costovertebral joints. Aerobic fitness is maintained with stationary cycling. Rowing is progressively introduced according to symptoms and strapping is used to support the ribs during training. Posture and technique is reviewed with the coach to eliminate unusual movements of the shoulder girdle.

Evaluation of suspected stress fractures

Stress fractures can occur if normal bone is exposed to repeated abnormal stress (fatigue fractures) or if normal stress is placed on bones with compromised elastic resistance (insufficiency fractures). This article describes two patients without a history of excessive stressful activity or apparent metabolic bone disease who developed bilateral distal tibial stress fractures. Different etiologies, clinical presentation, differential diagnosis, and diagnostic imaging modalities of stress fractures are discussed.

A prospective controlled study of diagnostic imaging for acute shin splints

OBJECTIVE

The purpose of this prospective, observational study was to examine the relationship of clinical examination, plain radiograph (XR), triple-phase bone scan (TPBS), and magnetic resonance imaging (MRI) in the investigation of patients presenting with acute shin splints.

METHODS

23 subjects with exercise induced lower leg pain and diffuse tibial tenderness of less than 3 months' duration were recruited. Subjects were excluded if there was clinical evidence of compartment syndrome, muscle hernia, or stress fracture. Each subject underwent XR, TPBS, and MRI within 2 wk of physical examination. Four asymptomatic controls underwent TPBS and MRI. Clinical findings, XR, TPBS, and MRI findings were independently recorded using a consistent template and subsequently analyzed. A single consensus lesion was chosen that provided the greatest overlap and highest grade to allow comparison of clinical and imaging findings. Sensitivity and specificity were calculated from data relating to clinical findings and diagnostic imaging.

RESULTS

Eighteen subjects had bilateral symptoms and five unilateral with a mean duration of symptom of 5.4 wk (+/- 3.5). Of 41 symptomatic lower legs, there were TPBS abnormalities in 36 and MRI findings in 34. Analysis of clinical findings to TPBS and MRI demonstrated a sensitivity and specificity of 84%, 33% and 79%, 33%, respectively. Assuming TPBS as the "gold-standard," MRI findings demonstrated a sensitivity of 95% and specificity of 67%. There was poor agreement between the grading of TPBS and MRI (k = 0.3). In the 5/46 asymptomatic limbs, 3/5 demonstrated uptake on bone scan and 4/5 signal change with MRI. Imaging abnormalities were similarly seen in the four control patients.

CONCLUSIONS

MRI may be used rather than TPBS and radiographs for evaluating acute tibial pain in athletes where avoidance of radiation exposure is desirable. Similar sensitivity and specificity may be expected from both investigations; however, in the light of abnormal TPBS and MRI findings in control and asymptomatic limbs, we recommend further studies be performed to define the extent of nonpathological TPBS and MRI changes.

Stress fractures

Stress fractures are being increasingly reported as a common cause of morbidity in both healthy populations and those with underlying diseases involving abnormal bone. An insight into the types and pathogenesis of stress fractures is necessary to considering the diagnosis, management and prevention of such conditions. The classification, aetiology and aspects of management are discussed.

A musculoskeletal radiologist's view of nuclear medicine

The introduction of cross-sectional and multiplanar imaging techniques has not diminished the value of radionuclide bone scanning. Skeletal scintigraphy remains an extremely effective and relatively inexpensive tool for diagnosis of many disorders of bones and joints. The sensitivity of scintigraphy in detecting stress fractures approaches 100%, although it is less specific than plain film radiography. However, radionuclide bone scanning can reveal subtle early changes in bone metabolism. For evaluation of infections, particularly in patients with diabetic foot neuropathy, scintigraphy is the modality of choice, although a combination of imaging techniques may be necessary in previously damaged bone. Radionuclide bone scanning has retained its place in the evaluation of primary bone tumors and metastases, and in screening of patients with metabolic bone disease. The radiologist should be aware that although this modality is generally used as an ancillary technique in conjunction with plain radiography, conventional tomography, computed tomography (CT), and magnetic resonance imaging (MRI), at times it can be used as the primary modality not only for the identification of skeletal lesions but also to provide important information required to make a definite diagnosis.

Leg injuries

Injuries in the leg span a broad spectrum of patient age and athletic level. Overuse injuries, such as medial tibial stress syndromes and stress fractures, tend to occur in the young athlete, whereas tennis leg usually occurs in the older population. With a few exceptions, most of these injuries can be successfully treated nonoperatively. Particularly with the young athlete, it is important to stress the necessity to rest and avoid activities that would compound the injury.

The superiority of magnetic resonance imaging in differentiating the cause of hip pain in endurance athletes

The accuracy of magnetic resonance imaging of the hip was prospectively evaluated in 19 military subjects engaged in endurance training. These patients had hip pain, negative radiographs, and radionuclide bone scans consistent with femoral neck stress fracture. Twenty-two hips were identified as positive for femoral neck stress fracture by bone scan. Each patient underwent magnetic resonance imaging and 6-week follow-up plain radiographs of the hips. Magnetic resonance imaging studies differentiated femoral neck stress fractures from a synovial pit, iliopsoas muscle tear, iliopsoas tendinitis, obturator externus tendinitis, avascular necrosis of the femoral head, and a unicameral bone cyst. The follow-up radiographs were used to verify the diagnosis of stress fracture. The radiographs showed healing callus in patients with stress fractures. Patients with diagnoses other than stress fractures had no changes on follow-up radiographs. Magnetic resonance imaging studies were as sensitive and much more specific than bone scan in determining the cause of hip pain. Radionuclide bone scan had an accuracy of 68% for femoral neck stress fractures with 32% false-positive results; MRI was 100% accurate. Magnetic resonance imaging proved to be superior to radionuclide bone scanning in providing an early and accurate diagnostic tool that aided in the differential diagnosis of hip pain in the young endurance athlete.

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.

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.

Patient compliance for successful stress fracture rehabilitation

The views and findings contained in this report are those of the authors and should not be construed as an official Department of the Army position, policy, or decision unless so designated by other official documentation. An avid 39-year-old female runner experiencing left groin pain was initially assessed as having a muscle strain but treated conservatively with crutch ambulation since the possibility of a left femoral neck stress fracture was not ruled out. A subsequent bone scan revealed a left medial femoral neck stress fracture. In the ensuing 18 months, evidence of stress fractures at multiple sites differing from the original fracture surfaced due to her noncompliance to the rehabilitation program and restrictions. Counseling for lifestyle modification were rejected by the patient. Resultant healing of her stress fracture was poor. Alerting clinicians to the importance of referral to behavior modification specialists from the onset of treatment for avid runners appears to be critical. In addition, a review of two other contributory factors possibly predisposing one to stress fractures was examined for consideration for future research.J Orthop Sports Phys Ther 1990;11(7):321-325.

Femoral neck stress fractures

Fifty-four femoral neck stress fractures were studied prospectively to evaluate treatment methods. Fifty-four fractures in 49 patients were identified in a 4 year prospective study that included 1,049 stress fractures of all types. From our evaluation of treatment methods, a modification of existing classification systems was developed based on radiographic findings and treatment. Differences from earlier studies were noted in racial diversity, in nonprogression of tension-side fractures, and in return to function.

[Medial tibial pain in runners]

Pain at the site of the tibial insertion of the flexor digitorum longus and the soleus near the middle third of the medial border of the tibia may be encountered in young athletes, who have usually started to run in late adolescence. Heel valgus, abnormal mid-foot pronation and excessive tibial torsion may be seen in association. The symptoms are brought on after excessive training. Radiographs may show cortical thickening at the site of the pain, and a bone scan may demonstrate a mild increase in the uptake of the isotope at this site. The pain appears to be related to a strain of the attachment of the flexor digitorum longus and the aponeurotic insertion of the soleus into the tibia. The pressure in the deep posterior compartment of the tibia is normal. Histological examination of specimens from the flexor digitorum longus may demonstrate ischaemic changes in the muscle. Treatment is based on an understanding of the biomechanics of the foot in running, modification of training methods and the use of suitable orthotics. If these measures fail, partial division of the aponeurotic attachment of soleus and freeing of the insertion of the flexor digitorum longus is usually successful.

Stress fractures in athletes. A study of 320 cases

We analyzed cases of 320 athletes with bone scan-positive stress fractures (M = 145, F = 175) seen over 3.5 years and assessed the results of conservative management. The most common bone injured was the tibia (49.1%), followed by the tarsals (25.3%), metatarsals (8.8%), femur (7.2%), fibula (6.6%), pelvis (1.6%), sesamoids (0.9%), and spine (0.6%). Stress fractures were bilateral in 16.6% of cases. A significant age difference among the sites was found, with femoral and tarsal stress fractures occurring in the oldest, and fibular and tibial stress fractures in the youngest. Running was the most common sport at the time of injury but there was no significant difference in weekly running mileage and affected sites. A history of trauma was significantly more common in the tarsal bones. The average time to diagnosis was 13.4 weeks (range, 1 to 78) and the average time to recovery was 12.8 weeks (range, 2 to 96). Tarsal stress fractures took the longest time to diagnose and recover. Varus alignment was found frequently, but there was no significant difference among the fracture sites, and varus alignment did not affect time to diagnosis or recovery. Radiographs were taken in 43.4% of cases at the time of presentation but were abnormal in only 9.8%. A group of bone scan-positive stress fractures of the tibia, fibula, and metatarsals (N = 206) was compared to a group of clinically diagnosed stress fractures of the same bone groups (N = 180), and no significant differences were found. Patterns of stress fractures in athletes are different from those found in military recruits. Using bone scan for diagnosis indicates that tarsal stress fractures are much more common than previously realized. Time to diagnosis and recovery is site-dependent. Technetium99 bone scan is the single most useful diagnostic aid. Conservative treatment of stress fractures in athletes is satisfactory in the majority of cases.

Shin splints--a literature review

"Shin splints" is not a specific diagnosis. It is merely a descriptive term that describes chronic exertional shin pain in an athlete. The evidence seems clear that shin splint pain has many different causes and this reflects the variation in the anatomy. It would be preferable to describe shin splint pain by location and aetiology, for example, lower medial tibial pain due to periostitis or upper lateral tibial pain due to elevated compartment pressure. This would aid communication between physicians and also direct therapy more accurately.