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Keywords:

  • Fatigue fractures;
  • Monarthritis;
  • Stress fracture;
  • Adult

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Objective

To examine etiologic factors, clinical features, and outcome in a series of consecutive patients with fatigue fractures diagnosed at a rheumatology division for a defined population over a 14-month period.

Methods

A prospective study of the patients diagnosed with fatigue fracture at the rheumatology division of the Hospital Xeral-Calde (Lugo, Spain) between July 2000 and August 2001 was conducted. Hormonal status, body mass index, lifestyle, job, underlying diseases, and drug intake, which might be attributable risk factors for the stress fracture, were assessed. In all the patients a followup of at least 6 months was required.

Results

Six consecutive patients (4 women) fulfilled the inclusion criteria. All of them were younger than 65 years (median 45 years; range 36–64 years) and had a body mass index lower than 25. In this series no distinctive occupation was found. The delay to diagnosis since the onset of symptoms ranged from 0.5 to 6 months (median 1.5). All patients but 1 were sent to the rheumatology division because of a clinical diagnosis of monarthritis. Pain and swelling were the presenting symptoms. Conventional radiographs were normal and fine needle aspiration of the joints yielded negative results for microcrystals and organisms. Magnetic resonance imaging disclosed the presence and site of fracture in all the cases. Sequelae of mechanical pain and subsequent osteoarthritis were observed in the 3 cases with longer delay to diagnosis.

Conclusion

Fatigue fractures are not exceptional in unselected adults. Rheumatologists should consider this diagnosis in patients presenting with monarthritis. Physician awareness is required to prevent the development of sequelae.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Stress fractures, although commonly seen by health care professionals caring for athletes, are a source of major and increasing importance for rheumatologists, because pain is the main symptom (1–4). Stress fractures can be classified into 2 groups. Fatigue fractures and insufficiency fractures (1–5). The first may occur when repetitive muscular forces or stresses are applied to a normal bone (6–8), and are most common in adolescents, athletes, and military recruits (3–5, 7–10). Insufficiency fractures, in contrast, are found when physiologic forces are applied to a weakened bone in patients with diseases such as osteoporosis, osteomalacia, and fibrous dysplasia (3, 5). Although insufficiency fractures and fatigue fractures are somehow overlapping conditions, in this report we have focused on patients with a diagnosis of fatigue fracture. Knowledge of the activities and risk factors associated with these disorders may increase clinical suspicion and help direct an appropriate evaluation. Thus, to further investigate this condition we have examined the etiologic factors, clinical features, diagnostic approach, and outcome in a series of consecutive patients with fatigue fracture diagnosed at the single referral hospital for a defined population in northwest Spain over a 14-month period.

PATIENTS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

A prospective study of the case records of all patients diagnosed with fatigue fracture at the rheumatology division of the Hospital Xeral-Calde (Lugo, Spain) between July 2000 and August 2001 was conducted. The Hospital Xeral-Calde is the only referral center for a well-defined population of almost 250,000 people living in the middle of the province of Lugo, in Galicia, northwest Spain (11). Thus, all patients aged 15 years and older seeking consultation due to rheumatic manifestations are sent to this division.

Inclusion criteria

The inclusion criterion for this study were the diagnosis of fracture by magnetic resonance imaging (MRI), a history of repetitive muscular forces or stresses (prolonged standing up or walking at work), and normal bone mineral density. Patients with weakened bone caused by other diseases, such as osteoporosis and osteomalacia, were excluded. Thus, for a diagnosis of fatigue fracture, an evaluation of bone mineral density by dual-energy x-ray absorptiometry (Norland Medical Systems, Fort Atkinson, WI) at the lumbar spine (L2–L4) yielding values (T score, Z score) within normal ranges was always required (12).

Data collection

Epidemiologic, clinical, and laboratory data at the time of diagnosis were extracted from their clinical records according to a specifically designed protocol and stored in a computerized file. They included age at the onset of symptoms, delay to diagnosis, sex, occupation, risk factors (alcoholism, smoking, eating disorders, and leg length differences), body mass index (BMI), presenting symptoms, and site of fracture. The following laboratory data were examined: complete blood count, coagulation tests, routine and bone chemistry profile (including calcium, phosphorus, magnesium, vitamin D, parathormone, and calciuria), thyroid stimulation hormone (TSH) and T4, circulating gonadotrophins (luteinizing hormone and follicle stimulating hormone), and testosterone. Diagnostic techniques, treatment, and outcome were also assessed. To evaluate sequelae (outcome), all patients were required to have had a followup of at least 6 months.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Between July 2000 and August 2001, 6 consecutive patients fulfilled the inclusion criteria described above. One of them has recently been described (13).

Epidemiologic factors in patients with fatigue fractures

The main clinical features are shown in Table 1. Four of the 6 patients were women, 2 of them were menopausal. However, all patients were younger than 65 years (median 45 years; range 36–64 years). All patients had a BMI lower than 25. In 1 of them, BMI was below 20. In this series, no distinctive occupation was found. However, both men were bricklayers and were engaged in excessive alcohol intake (more than 100 gm ethanol/day). None of the patients recalled a history of trauma prior to the onset of symptoms. The time to diagnosis since the onset of symptoms ranged from 0.5 to 6 months (median 1.5 months).

Table 1. Epidemiologic findings in 6 patients with fatigue fractures*
No./sex/ageRisk factorsOccupationWeight/height, kg/cmBody mass indexHormonal statusDelay to diagnosis, months
  • *

    Body mass index was calculated as weight (in kilograms) divided by height (in meters) squared; <20: lean; 20–25: normal.

1/F/45NoneJanitor68/16624.64Normal0.5
2/F/36NoneNurse53/16020.70Normal0.5
3/M/44AlcoholismBricklayer69/18021.29Normal2
4/M/45Smoking and alcoholismBricklayer61/17320.40Normal6
5/F/64NoneSchoolmaster57/16820.21Menopause1
6/F/56NoneHousewife51/16518.75Menopause3

Main clinical features and laboratory data in patients with fatigue fractures

All patients but 1 were sent to the rheumatology division because of a clinical diagnosis of monarthritis. Pain and swelling were the presenting symptoms. Conventional radiographs were normal and fine needle aspiration of the joints (performed in all but patient 5) disclosed scarce amount of bloody material, which yielded negative results for microcrystals and organisms. Elevation of erythrocyte sedimentation rate (higher than 20 mm/first hour) was detected in 4 patients. Complete blood count, coagulation tests, routine biochemistry profile, bone metabolism variables, and TSH and T4 levels were normal. MRI disclosed the presence and site of fracture in all cases. The sites of fracture are shown in Table 2. Figure 1 and 2 show MRI findings observed in a patient with fatigue fracture. Bone scintigraphy scan disclosed increased uptake at the site of fracture in the 4 patients on whom it was performed (Figure 3).

Table 2. Main clinical features and laboratory data of 6 patients with fatigue fractures*
No./sex/agePresenting symptomClinical diagnosis on admissionESR at diagnosisSite of fractureDiagnostic techniqueTreatmentSequelae
  • *

    ESR = erythrocyte sedimentation rate, in millimeters first hour; MRI = magnetic resonance imaging.

1/F/45Pain and swellingMonarthritis45Left tibiaMRIImmobilizationNo
2/F/36Pain and swellingMonarthritis11Second metatarsalMRIImmobilizationNo
3/M/44Pain and swellingMonarthritis24Midtarsal bonesMRIImmobilizationOsteoarthritis
4/M/45Pain and swellingMonarthritis31Left tarsal talusMRIImmobilizationOsteoarthritis
5/F/64Talalgia and swellingBilateral heel pain28Bilateral calcaneusMRIImmobilizationNo
6/F/56Pain and swellingMonarthritis12Left tarsal talusMRIImmobilizationOsteoarthritis
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Figure 1. Initial coronal T2-weighted magnetic resonance image with fat saturation showing serpiginous lines of high signal density parallel to the subchondral bone plate of the talar dome, which represented stress fractures. Poorly delimited regions of high signal intensity in the distal tibia and calcaneus (stress response) were also observed. Note the periarticular and tibial subperiosteal edema.

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Figure 2. Coronal T2-weighted magnetic resonance image of the same patient as Figure 1 performed 3 months later showing almost complete regression of the lesions. Minimal edema in the calcaneus and a thin low signal intensity line parallel to the talar bone was still present.

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Figure 3. 99mTc bone scan showing high focal uptake at the site of fractures.

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Treatment and outcome

Conservative treatment with immobilization and nonsteroidal antiinflammatory drugs was prescribed to all the patients. Sequelae of mechanical pain and subsequent osteoarthritis were observed in 3 patients (Table 2). This complication occurred in the 3 cases with longer delays to diagnosis.

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES

Fatigue fractures are still not very familiar to many clinicians, including rheumatologists. The recognition of this entity may be particularly difficult in some cases, as initial plain radiographic findings may be normal (14). They result from repetitive, cyclic loading of bone, which overwhelms the reparative ability of the skeletal system (7, 8). Due to the higher incidence among athletes (15), the effect of exercise on bone fractures has received much attention in recent years. Among female athletes, a number of risk factors including low bone mineral density, menstrual irregularities, dietary factors, and prior fractures have been associated with an increased risk for fatigue fractures (16). In adolescents and children, fatigue fractures have been reported (17) and in these cases a differential diagnosis with other conditions such as osteomyelitis, eosinophilic granuloma, osteogenic sarcoma, and Ewing sarcoma is required (18).

Our prospective study constitutes an attempt to examine the frequency and features of fatigue fractures in a series of adults diagnosed at the single rheumatology division for a defined population. Thus, the present study provides the first analysis on epidemiologic, clinical, and laboratory features, as well as treatment and outcome in a series of unselected patients with fatigue fracture. Due to this, patients with osteoporotic insufficiency fractures were excluded.

Our division provides medical care to patients complaining of rheumatic features who attend both the outpatient rheumatology clinic and the emergency department of our hospital. This fact gives us more comprehensive information on patients presenting at the hospital with musculoskeletal manifestations. The relative frequency of fatigue fractures with regard to all patients diagnosed as having monarthritis within the study period was 3%.

As previously reported in our series, women outnumbered men. However, none of the patients was engaged in sporting activities. In addition, we did not diagnose adolescents with this problem during the period of study. In most cases, these fractures mimicked a monarthritis due to their proximity to the joints.

In athletes, fatigue fractures were more commonly found in tibia, metatarsal, femur, and tarsal navicular bones (2, 3, 15). In the present series, besides the former sites, midtarsal bones, talus, and calcaneus were also involved. It is difficult to explain the reasons for fatigue fractures in our series of nonathletes. It is possible that a history of repetitive loading, including prolonged standing and walking at work, and alcoholism in individuals with normal or low body mass index might have played a role.

Conventional radiographs continue to be used as a primary method for the diagnosis of fatigue fractures. However, as in our cases, initial plain radiographs may be normal (19). Although bone scintigraphy has generally been considered the gold standard test for the diagnosis of fatigue fractures (2), in our experience MRI proved to be more precise at detecting the injury site, extent, and characteristics of the lesion early in the course of the disease (14).

Rest with progressive reintroduction of activity is the treatment chosen for the majority of patients with fatigue fractures (19). However, as observed in our series, when the condition is untreated for a long time, osteoarthritis and chronic pain are likely to occur.

In conclusion, fatigue fractures are not exceptional in unselected adults. Rheumatologists should consider this diagnosis in patients presenting with monarthritis.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. REFERENCES