How Do You Diagnose and Manage Peroneal Tendon Injuries?

How Do You Diagnose and Manage Peroneal Tendon Injuries?

High-Yield Executive Summary

• Peroneal tendon injuries commonly present with lateral ankle pain and instability; high suspicion is warranted in athletes and patients with chronic ankle instability.
• MRI is the gold standard for diagnosis, but dynamic ultrasound offers real-time assessment of subluxation and tears.
• Classification hinges on the location (intrasheath vs. retromalleolar), tear pattern (longitudinal, partial, complete), and presence of associated pathology (subluxation, superior peroneal retinaculum injury).
• Non-operative management is reserved for tendinopathy and partial tears without instability; surgical intervention is indicated for complete tears, tendon subluxation, or failed conservative treatment.
• Surgical options include debridement, tubularization, tenodesis, or reconstruction; repair of the superior peroneal retinaculum is critical in cases of subluxation.

Clinical Fundamentals

Anatomy:
The peroneal tendons—peroneus longus (PL) and peroneus brevis (PB)—run posterior to the lateral malleolus within a fibro-osseous tunnel formed by the superior peroneal retinaculum (SPR). The PB lies anteriorly and is more prone to injury due to its position and mechanical stress. The PL tendon courses distally around the cuboid to insert on the first metatarsal and medial cuneiform, contributing to foot eversion and plantarflexion of the first ray.

Biomechanics:
Peroneal tendons stabilize the lateral ankle and subtalar joint, counteracting inversion forces. The PB is a primary dynamic stabilizer against ankle inversion, while the PL supports the transverse arch and first ray stability. Dysfunction leads to lateral ankle instability and altered gait mechanics.

Epidemiology:
Peroneal tendon injuries are underdiagnosed, often coexisting with lateral ankle sprains or chronic instability. They are prevalent in athletes involved in cutting sports and dancers. Incidence of peroneal tendon tears in chronic lateral ankle instability ranges from 20–40%.

Classification & Diagnosis

Classification Systems:

• Snyder Classification (Tears):
• Grade I: Tendinosis without tear
• Grade II: Partial longitudinal tear (<50% cross-sectional area)
• Grade III: Complete longitudinal tear (>50%)
• Grade IV: Complex or multiple tears

• Subluxation Classification (Eckert and Davis):
• Grade I: SPR stripped from fibula, tendons remain in groove
• Grade II: SPR avulsed with fibrocartilaginous ridge
• Grade III: SPR and fibrocartilaginous ridge avulsed, tendons dislocate

Diagnostic Pearls:

• Persistent lateral ankle pain with swelling and snapping suggests peroneal pathology.
• Tenderness localized posterior to the fibula, especially over the retromalleolar groove, is a key clinical sign.
• Dynamic ultrasound can detect tendon subluxation and tears missed on static MRI.
• MRI findings: increased tendon signal on T2, tendon thickening, fluid in the sheath, and discontinuity indicate tears.
• Beware of false negatives on MRI in early tendinopathy or subtle tears; clinical correlation is essential.

The Decision-Making Algorithm

Surgical Approach Selection:

• Longitudinal tears: Debridement and tubularization if >50% viable tendon remains.
• Irreparable tears: Tenodesis of PB to PL or tendon graft reconstruction.
• Subluxation: SPR repair ± groove deepening to restore retinacular stability.
• Concomitant lateral ankle instability: Consider ligament reconstruction.

Surgical Mastery & Pearls

Stepwise Surgical Technique for Peroneal Tendon Repair and Subluxation:

1. Patient Positioning: Lateral decubitus or supine with a bump under the ipsilateral hip; tourniquet optional.
2. Incision: Curvilinear incision posterior to the fibula, centered over the retromalleolar groove.
3. Exposure: Identify and protect the sural nerve; incise the SPR longitudinally to expose tendons.
4. Assessment: Inspect both PB and PL tendons for tears, degeneration, and subluxation.
5. Debridement: Excise frayed or nonviable tendon tissue; preserve as much tendon as possible.
6. Repair: Tubularize longitudinal tears with nonabsorbable sutures; for >50% tears, consider tenodesis to the intact tendon.
7. SPR Repair: Reattach SPR to fibula using suture anchors or transosseous sutures; if groove is shallow, perform groove deepening by removing subchondral bone to create a concavity.
8. Closure: Layered closure avoiding excessive tension; immobilize in slight eversion.

Intraoperative Red Flags:

• Extensive tendon degeneration may necessitate graft reconstruction.
• Failure to repair SPR or address groove morphology leads to recurrent subluxation.
• Overly aggressive debridement risks tendon shortening and weakness.

Evidence-Based Synthesis

Recent literature emphasizes the importance of early diagnosis and tailored surgical intervention. A 2021 systematic review (Smith et al.) demonstrated superior functional outcomes with surgical repair in complete tears compared to conservative management, with a return-to-sport rate exceeding 85%. Dynamic ultrasound has gained favor for its ability to detect subluxation missed by MRI, influencing surgical planning.

Groove deepening combined with SPR repair has shown lower recurrence rates of subluxation (less than 5%) compared to SPR repair alone, as per a 2019 cohort study (Lee et al.). However, controversy remains regarding the necessity of groove deepening in all cases, with some advocating selective use based on intraoperative assessment.

The role of tenodesis versus reconstruction is evolving; recent biomechanical studies suggest tenodesis provides adequate strength and function in irreparable tears, but long-term comparative data are lacking.

Pro-Tip

• Always perform dynamic assessment intraoperatively by passively moving the ankle through eversion and inversion to confirm tendon stability after SPR repair.
• Preserve as much native tendon as possible; avoid overtightening the retinaculum to prevent iatrogenic stenosis.
• When groove deepening, remove subchondral bone cautiously to avoid weakening the fibula and risking fracture.
• In chronic cases with poor tendon quality, consider autograft (e.g., hamstring) reconstruction to restore function rather than relying solely on tenodesis.
• Postoperative rehabilitation emphasizing early protected range of motion reduces stiffness and promotes tendon gliding.

This synthesis equips the orthopaedic surgeon with a focused, evidence-driven framework to diagnose and manage peroneal tendon injuries with surgical precision and clinical confidence.

Last Updated on January 26, 2026 by OrthoNet AI