Stress fractures of the distal fibula presenting as monarticular flares in patients with rheumatoid arthritis

Changes in microarchitectural characteristics at the tibial epiphysis induced by collagen-induced rheumatoid arthritis over time

Background

Little is known about the time course of changes in the microarchitecture of the tibial epiphysis with rheumatoid arthritis (RA), although such information would be valuable in predicting risk of fracture. Therefore, we used in vivo microcomputed tomography (μ-CT) to assess patterns of microarchitectural alterations in the tibial epiphysis using collagen-induced RA in an animal model.

Methods

Bovine type II collagen was injected intradermally into the tails of rats for induction of RA. The tibial joints were scanned by in vivo μ-CT at 0, 4, and 8 weeks following injection. Microarchitectural parameters were measured to evaluate alteration patterns of bone microarchitecture at the tibial epiphysis.

Results

The microarchitectural alterations in an RA group were significantly different from those in a control group from 0 to 4 weeks and from 4 to 8 weeks following injection (P < 0.05). The distribution of trabecular bone thickness and trabecular bone separation from 0 weeks to 8 weeks differed significantly (P < 0.05).

Conclusion

These results indicate that the patterns of microarchitectural alterations at the tibial epiphysis are strongly affected by collagen-induced progression of RA and entail a severe risk of fracture at the tibial epiphysis. This study represents a valuable first approach to tracking periodic and continuous changes in the microarchitectural characteristics of the tibial epiphysis with collagen-induced RA.

Bilateral tibial stress fracture presenting as painful edemas in lower limbs

Bilateral stress fracture of the tibia is infrequent. This paper presents an unusual case of a 73-year-old man who sustained a bilateral stress fracture of the tibia presenting as painful edemas in lower limbs. The radiographic and scintigraphic examination confirmed the diagnosis of the fractures. In addition, the patient was receiving androgen deprivation therapy with GnRH analogs for the treatment of prostate cancer and the bone density measurements confirmed the presence of osteoporosis. Treatment with restricted weight bearing was associated with improvement of clinical symptoms. Early recognition and diagnosis of this injury is essential for treating the underlying osteoporosis as well as the fracture.

Clinical aspects of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease of unknown etiology affecting both articular tissues and extraarticular organs. The disease is often progressive and results in pain, stiffness, and swelling of joints culminating in significant morbidity and increased mortality. This chapter discusses the epidemiology, possible etiology, clinical manifestations, diagnostic approach and treatment options of RA.

Stress fractures

Stress fractures are common over-use injuries which include fatigue and insufficiency fractures. Athletes, soldiers and osteoporotic patients are some of the individuals at high risk for the development of this injury. Owing to the low sensitivity of plain radiography at the onset of symptoms the diagnosis of this entity may be easily overlooked. Occasionally, some of these fractures, such as tibial fracture in children and fractures in the clavicle and pelvic ring, can be misdiagnosed as tumoral or infectious processes; moreover, although most stress fractures are uncomplicated and can be managed by rest and restriction from precipitating activity, a subset of these fractures can present a high risk for progression to complete fracture or non-union problems. All of this indicates that the various types of stress fracture, owing to their different clinical characteristics and evolution, should be commented on in detail. In this chapter different types of stress fracture are described with special reference to their localization, clinical characteristics, evolution and treatment.

Insufficiency fractures of the tibia and fibula

OBJECTIVE

Insufficiency fractures (IF) occur when normal or physiological muscular activity stresses a bone that is deficient in mineral or elastic resistance. IF of the tibia and fibula are probably less common than IF of the ribs, vertebrae, hip, pelvis, and distal ulna, and therefore they are frequently underrecognized and mistaken for other conditions. Our aim was to analyze the main features and outcome of IF of the tibia and fibula in patients attending our Rheumatology Service.

METHODS

IF was considered when occurring spontaneously or with minimal trauma. Between January 1984 and July 1997, 25 patients were diagnosed as having IF of the tibia and fibula. The main predisposing factors, clinical features, therapy, and outcome were retrospectively reviewed.

RESULTS

All the patients except four were women (mean age, 66+/-12 years). Three cases were diagnosed between 1984 and 1990 (0.42 cases/year) and 22 between 1991 and 1997 (three cases/year). Eighteen patients had an underlying condition: rheumatoid arthritis (RA, 13 cases), psoriatic arthritis (2), systemic lupus erythematosus (SLE) (1), kidney transplant (1), and Crohn's disease (1). Eleven patients had osteoporotic fractures in other locations. Risk factors for osteoporosis were corticosteroids (13 cases), prolonged immobilization (10), early menopause (2), and methotrexate therapy (10). All patients had pain on weight bearing and marked functional impairment, 16 had local inflammatory signs, and 10 had deformity. In only five patients the diagnosis of IF was considered at the first examination. The diagnostic delay was 76+/-117 days (median, 21). The initial radiograph was diagnostic in 20 patients, and in the remaining the diagnosis was made by computed tomography (CT) scan (three cases), magnetic resonance imaging (MRI) (1), and bone scan (1). IF were located as follows: tibia (10 cases), fibula (seven), tibia and fibula (eight). Nineteen patients were treated with conservative management, four received no specific treatment, and two required surgery. Sixteen patients were hospitalized for a mean period of 12+/-8 days. Most patients had complete recovery. The high frequency of IF seen in RA patients is probably due to the severe disease in patients treated by our Service and that such patients have a higher risk for osteoporosis and its complications.

CONCLUSIONS

IF of the tibia and fibula are probably more common than previously thought. They usually occur in patients with underlying rheumatic diseases, mainly RA, and are frequently mistaken for other joint and bone conditions. Despite a frequent delay in diagnosis, they have a good prognosis with conservative management. Nonetheless, a higher index of suspicion may avoid unnecessary investigations and treatments.

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.