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