What is the best course of treatment for a patient with a history of partial peroneus brevis tendon tear presenting with new onset pain and a visible bunion?

Clinical Assessment and Differential Diagnosis

The visible hard lump is most likely not related to the previous peroneus brevis tendon tear and requires separate evaluation to distinguish between a true bunion (hallux valgus deformity) versus other pathology such as recurrent peroneal tendon pathology, os peroneum fracture, or fibular ridge prominence.

The key clinical distinction here is anatomical location:

• Bunions occur at the first metatarsophalangeal joint on the medial forefoot, not in the lateral ankle/peroneal region where the previous tendon tear occurred 1, 2
• Peroneus brevis pathology presents with posterolateral ankle pain and swelling along the retrofibular region, often with pain on eversion and potential tendon subluxation 1, 2, 3

Critical Physical Examination Findings to Clarify the Diagnosis

• Palpate for swelling specifically along the course of the peroneal tendon sheath behind and below the lateral malleolus—this suggests recurrent peroneal pathology 2, 3
• Test for pain with resisted eversion of the foot, which is diagnostic of peroneal tendon pathology 2
• Assess for subluxing or dislocating peroneal tendons with active dorsiflexion and eversion—this predisposes to longitudinal tears 1, 2
• Examine for lateral ankle instability ("giving way"), which commonly coexists with peroneus brevis tears 1, 4
• Evaluate for hindfoot varus deformity, present in approximately 21% of patients with chronic peroneal tears and a contributing factor 4

Diagnostic Imaging Strategy

If the hard lump is in the lateral ankle region (not medial forefoot), obtain MRI or ultrasound to evaluate for recurrent peroneal tendon pathology:

• MRI has 83.9% sensitivity and 74.5% specificity for peroneal tendinopathy, and 54.5% sensitivity and 88.7% specificity for tendon tears 5
• Ultrasound demonstrates 100% sensitivity and 90% accuracy for peroneal tendon tears when performed by an expert, and is superior for detecting dynamic subluxation with 100% positive predictive value 5
• Important caveat: Up to 34% of asymptomatic patients have peroneus brevis tears on MRI, so correlation with clinical findings is essential 5

Initial Conservative Management (If Peroneal Tendon Pathology Confirmed)

• NSAIDs (oral or topical) for short-term pain relief, though they don't affect long-term outcomes 5
• Topical NSAIDs eliminate gastrointestinal hemorrhage risk while providing equivalent pain relief 5
• Cryotherapy through wet towel for 10-minute periods for acute pain relief 5
• Relative rest—avoid activities that worsen pain while maintaining activities that don't aggravate symptoms 5
• Ankle bracing for support in cases with instability 3
• Eccentric strengthening exercises once acute pain subsides 5

When Conservative Management Fails

Surgical repair is the standard of care for symptomatic peroneus brevis tears, particularly if conservative measures fail after 3-6 months:

• For less extensive tears: débridement and tubularization (side-to-side sutures) 2, 3
• For severe tears: resection of damaged tendon and tenodesis to the peroneus longus 2, 3, 4
• If lateral ankle instability coexists: anatomical reconstruction of lateral ankle ligaments must be performed simultaneously 1, 4
• If superior peroneal retinaculum is torn: reconstruction is necessary to prevent recurrent subluxation 1
• If hindfoot varus is present: corrective osteotomy should be considered to prevent progressive deformity 4

Critical Pitfalls to Avoid

• Do not inject corticosteroids into or near the peroneal tendons—this inhibits healing, reduces tensile strength, and may predispose to rupture 5
• Do not assume the "hard lump" is a bunion without confirming its anatomical location—bunions are medial forefoot deformities, not lateral ankle masses
• Do not overlook concomitant lateral ankle instability—present in approximately 28% of cases and requires simultaneous surgical correction 1, 4
• Do not delay surgical referral beyond 3-6 months if conservative treatment fails, as chronic tears have worse outcomes 2, 3