What is the recommended treatment for a patient with a normal appearing peroneal tendon and nerve, but with subcutaneous fluid adjacent to the fibula, presenting with pain, likely due to a recent injury or overuse?

Treatment for Subcutaneous Fluid Adjacent to Fibula with Normal Peroneal Structures

This presentation most likely represents localized soft tissue inflammation or bursitis rather than tendinopathy, and should be treated with conservative measures including relative rest, cryotherapy, and NSAIDs, with close monitoring to ensure the peroneal tendons and nerve remain unaffected.

Initial Conservative Management

The finding of subcutaneous fluid with normal-appearing peroneal tendons and nerve indicates a localized soft tissue process rather than tendon or nerve pathology. Treatment should focus on reducing inflammation and preventing progression:

• Apply cryotherapy through a wet towel for 10-minute periods to provide effective short-term pain relief at the site of subcutaneous fluid 1
• Implement relative rest by decreasing activities that load or irritate the lateral ankle region, but avoid complete immobilization which leads to muscle atrophy 1
• Prescribe NSAIDs for short-term pain relief to address the inflammatory component causing pain 1
• Consider topical NSAIDs as they provide similar pain relief with fewer systemic side effects for this localized process 1

Monitoring for Peroneal Pathology

While the peroneal structures currently appear normal, vigilance is essential as subcutaneous fluid near the fibula can be associated with developing peroneal tendon pathology:

• Monitor for signs of peroneal tendon involvement including swelling along the tendon sheath, pain with eversion, or subluxing tendons, as these indicate progression to true peroneal pathology 2
• Assess for lateral ankle instability which commonly coexists with peroneal tendon problems and can place strain on surrounding structures 3
• Watch for development of chronic lateral ankle pain, as up to 40% of patients with ankle injuries experience persistent symptoms that may indicate undiagnosed peroneal tendon injury 4

If Symptoms Persist Beyond 2-4 Weeks

• Re-evaluate with repeat imaging if pain persists or worsens, as peroneal tendon tears are frequently underdiagnosed and may not be apparent on initial imaging 4, 2
• Consider MRI if clinical suspicion increases for peroneal tendon pathology, particularly if physical examination reveals tenderness along the peroneal tendon course or pain with resisted eversion 4

Rehabilitation Protocol if Tendinopathy Develops

Should the subcutaneous fluid progress to involve the peroneal tendons:

• Initiate eccentric strengthening exercises as they are highly effective for treating tendinopathy and may reverse degenerative changes 1
• Implement deep transverse friction massage to reduce pain in tendinopathies 1
• Expect 80% of patients to fully recover within 3-6 months with appropriate conservative management 1

Common Pitfalls

• Do not dismiss as simple ankle sprain - peroneal tendon injuries are frequently misdiagnosed as ankle sprains, leading to chronic lateral ankle pain 4, 2
• Avoid corticosteroid injections at this stage - while they may provide short-term relief, they can inhibit healing and reduce tendon tensile strength if tendon involvement develops 1
• Do not completely immobilize - this accelerates muscular atrophy and deconditioning 5