Peroneal Tendon Problems

Two Main Types of Problems

  1. Degenerate Tears
    • Usually Peroneus Brevis just distal to fibula
    • Peroneus Longus tears occur as longus hooks under cuboid at the Os Peroneum
  2. Instability due to tears of the Superior Peroneal Retinaculum (SPR)
    • Acute tears
      • Rare occurrence

Pathoanatomy

  • PB and PL originate from the posterior aspect of the fibula
  • PB is always closest to bone
  • Both pass over the Calcaneofibular ligament (CFL)
  • Stabilized by the superior and inferior peroneal retinaculum
  • Lie in a groove on the posterior aspect of fibula
  • Inferior to SPR, they are separated by peroneal tubercle on calcaneus
  • Insertion Points:
    • PB inserts on 5th MT base
    • PL runs in cuboid groove to insert on 1st MT base
  • Functions:
    • Both evert the subtalar joint (STJ) and dorsiflex the ankle
    • PB has a hypovascular zone just distal to fibula, PL at the inferior peroneal retinaculum (IPR)

Tears

Peroneus Brevis (PB)

  • Occur at level of or just below Superior Peroneal Retinaculum
  • 3 times more common than PL tears
  • Highly associated with lateral ankle sprains
  • Mechanism:
    • Abrasion on fibula edge
    • Compression against fibula by PL
  • Usually longitudinal intrasubstance tears
  • 10% are complete tears

Peroneus Longus (PL)

  • Occur between IPR and cuboid base on lateral aspect of calcaneus
  • Highly associated with Pes Cavus (varus hindfoot position)
  • XR may show:
    • Retracted Os Peroneum
    • Fractured Os Peroneum
  • Usually longitudinal tears
  • 10% are complete
  • 10% involve both tendons

Instability

  • Tearing of the SPR causes lateral instability of both tendons
  • Strongly associated with:
    • Ankle instability
    • Shallow fibula groove predisposing to subluxation

Clinical Features

  • History of injury
  • Popping or clicking on lateral aspect
  • Pain well localized normally
  • Visible subluxation if instability – reproducible by patient
  • Test Power:
    • PB – Resisted eversion with ankle plantarflexed
    • PL – Resisted eversion and 1st ray dorsiflexion
  • Screen for:
    • Pes cavus (may need correction)
    • Ankle instability

Imaging

X-Ray (XR)

  • May show fractured or displaced Os Peroneum
  • SPR rupture may avulse a small piece of fibula

MRI

  • Shows longitudinal tears as high signal within tendon

Arthrography of Ankle

  • Dye seeping into peroneal tendons indicates rupture of CFL

Management

Non-Operative

  • Symptomatic
  • Corrective insoles if underlying flexible pes cavus
  • Bracing if concurrent ankle instability
  • Physiotherapy

Surgical Treatment of Tears

Peroneus Brevis (PB)

  • >50% tendon remaining → Repair or tubularize
  • <50% tendon remaining → Debride and attach to peroneus longus
  • Complete Tears:
    • Repair early or
    • Sewn to PL
    • Bridged with Plantaris graft
    • FHL or FDL transfer

Peroneus Longus (PL)

  • If Os Peroneum fracture → Excise
  • Treat longus tears as per Brevis algorithm

Both Tendons Completely Torn

  • Bridge graft (plantaris) or tendon transfer of FHL/FDL

Surgical Treatment of Instability

  • Anatomic repair of SPR with suture anchors
  • Concurrent deepening of peroneal groove on posterior aspect fibula if shallow
  • If chronic and SPR irreparable:
    • Use plantaris graft to replace retinaculum
  • Treat ankle instability through the same incision if necessary
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