Essential Insights On Managing The Rheumatoid Foot
Given the challenges that rheumatoid arthritis can pose with lower extremity deformities, this author reviews essential diagnostic considerations, offers a primer on common arthritis medications and potential side effects, and provides pertinent insights on surgical procedures that may have an impact.
Rheumatoid arthritis (RA) is a seropositive immunological disease of the body that often manifests in the foot with significant deformities and is estimated to affect 1 to 2 percent of the population. It is a progressive, debilitating disease that can present in the skin as ulcerations, in the subcutaneous tissues as rheumatoid nodules, in the blood vessels as rheumatoid vasculitis, and in the eyes, kidneys and liver.
In our practice, we estimate that 25 percent of RA positive patients present with significant foot and ankle problems. At any one time, nearly 50 percent of patients with RA have active symptoms involving the foot and ankle.1
Rheumatoid arthritis can have a “classic” presentation with hypertrophy of the metatarsal heads, pain and clawtoes. The chronic RA patient will have lesser metatarsophalangeal joint (MPJ) deformities and the disease often manifests with polyarthropathy. When faced with a multitude of symptoms and deformities, the foot and ankle surgeon can find RA to be challenging.
Among the general population, women are more frequently afflicted with RA than men. Typically, the patient is an older female who presents with generalized aches and pains, often with severe pain lingering in the foot. The patient also has difficulty walking and getting shoes fitted. The patient’s feet can look like those of a typical bunion patient with intractable porokeratosis (IPKs) or have the characteristic look of degenerative joint disease (DJD) of all the lesser metatarsal joints and rearfoot. Patients often state their chief complaint as their feet being deformed and having seen their parents and grandparents suffer from this deformity. While the disease occurs most often in adults, it can manifest in a childhood form.
Salient Diagnostic Insights
Rheumatoid arthritis in the foot has a classic appearance both clinically and radiographically. Clinically, the appearance of a patient with RA may include multiple metatarsalgia (often “lumps and bumps”) with prominent, hypertrophic metatarsal heads and limited range of motion at the ankle. The patient often complains of pain and swelling that are not relieved by narcotic analgesics.
Other RA deformities include hallux rigidus, clawtoes and digital deformities such as overlapping digits. There is usually an equinus present and the patient often cannot dorsiflex the foot, sometimes due to a talonavicular spur that limits range of motion. The midfoot and rearfoot are usually affected with arch collapse and one may see a rocker bottom deformity in late stages of the disease.
Synovitis is usually a pathognomonic sign and biopsy is helpful in this regard. Articular cartilage degenerates and one sees attenuation and non-functional tendons, often swollen with tenosynovitis. Imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT) and bone scan can be very helpful in making a definitive diagnosis.
Radiographically, RA presents with subluxation and dislocation of the lesser MPJs. When there is a high index of clinical suspicion of RA, the medical management team often diagnoses RA via laboratory analysis with many proprietary labs offering an “arthritis panel” to test patients with an analysis of lab data such as rheumatoid factor (RF), antinuclear antibodies (ANA), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).