How to manage tendon friction rubs in systemic sclerosis?

How to Perform a Tendon Friction Rub Examination

Tendon friction rubs (TFRs) are palpated by placing your fingers over tendons during active or passive joint movement, feeling for a coarse, leathery crepitus that indicates fibrinous tenosynovitis—this is a critical prognostic sign in systemic sclerosis that identifies patients at high risk for diffuse disease, organ complications, and mortality. 1

Examination Technique

Location and Method

• Examine common sites systematically: wrists (flexor and extensor tendons), fingers (flexor tendons), ankles (Achilles and tibialis tendons), knees (patellar tendon), and elbows 2, 1
• Palpation technique: Place your fingertips directly over the tendon and ask the patient to actively move the joint through its full range of motion 1
• Alternative method: Passively move the joint while maintaining firm contact over the tendon 1
• Characteristic finding: A palpable friction rub feels like a coarse, leathery crepitus or grinding sensation—distinctly different from joint crepitus or soft tissue edema 1

Documentation

• Record the number and location of all palpable TFRs, as the presence of ≥1 TFR is prognostically significant 3, 1
• Note bilaterality if present, though even unilateral findings are clinically important 1

Clinical Significance and Risk Stratification

Prognostic Implications

• TFRs predict diffuse cutaneous SSc: They are one of the best predictors of evolution to diffuse scleroderma in multiple regression analyses 1
• Mortality risk: Patients with TFRs have significantly reduced 5-year and 10-year survival rates compared to those without TFRs 3
• Organ involvement: TFRs confer a >2-fold increased risk of developing scleroderma renal crisis, cardiac complications, and gastrointestinal disease, even after adjusting for other risk factors 3
• Progressive disease: TFRs are independently associated with progressive disease over 1 year, increasing the predicted chance of progression from 37% to 67-89% 4

High-Risk Patient Identification

• TFRs identify patients requiring intensive monitoring for renal crisis (blood pressure checks, home monitoring), cardiac involvement (arrhythmias, heart failure), and gastrointestinal complications 5, 3
• Scleroderma renal crisis risk factors include TFRs combined with high skin scores, joint contractures, rapidly progressive skin involvement, and corticosteroid use ≥10-15 mg/day 5, 6

Management Implications When TFRs Are Present

Immediate Actions

• Avoid high-dose corticosteroids (≥15 mg/day prednisone): These increase scleroderma renal crisis risk 4-fold when used within 6 months preceding onset 5, 6
• If steroids are necessary, use ≤10 mg/day and monitor blood pressure and renal function closely 5, 7
• Initiate home blood pressure monitoring to detect early renal crisis 5

Treatment Considerations

• TFRs may respond to low-dose corticosteroids (≤10 mg/day) or immunosuppression similar to inflammatory arthritis, though evidence is limited 2
• Consider mycophenolate mofetil or methotrexate for early diffuse cutaneous SSc with TFRs, as these patients require disease-modifying therapy 7, 2
• Occupational hand therapy including range of motion exercises should be initiated early for patients with TFRs affecting hand function 2

Common Pitfalls to Avoid

• Do not confuse TFRs with joint crepitus: TFRs are felt over tendons during movement, not within the joint space itself 1
• Do not dismiss a single TFR: Even one palpable friction rub significantly increases risk for poor outcomes 3, 1
• Do not use high-dose steroids in patients with TFRs and early diffuse disease, as this dramatically increases renal crisis risk 5, 6
• Do not delay organ screening: Patients with TFRs require comprehensive evaluation for pulmonary, cardiac, renal, and gastrointestinal involvement at baseline and regular intervals 5, 3