Peroneal Tendon Instability



  • The peroneus longus and brevis muscles originate from the proximal and distal fibula respectively
  • The tendons travel together behind the distal fibula through a tunnel between the superior peroneal retinaculum and the calcaneum
  • A groove in the posterior fibula also helps to contain these tendons along with a collagenous ridge extension (see image below); here, brevis sits anterior to longus
  • The brevis tendon continues distally to attach to the proximal aspect of the 5th metatarsal
  • The longus tendon continues under the foot to attach to the lateral aspect of the medial cuneiform and the plantar aspect of the 1st metatarsal base


Spectrum of disease

  • Peroneal tendon instability can involve one or both tendons, the retinaculum, or the bones around them
  • Acute injuries occur from rapid dorsiflexion of an inverted foot with concurrent contracture of the peroneal tendons
  • One or both tendons can have partial or full tears that lead to pain and instability
  • The most common injury is a peroneus brevis partial longitudinal tear; there may also be a concurrent injury to the superior peroneal retinaculum as described below



  • c. 4% of all ankle injuries
  • seen in younger, more athletic patients
  • peroneal tendons tears are found in 33-66% of patients that describe lateral ankle instability


Presentation and examination

  • appropriate mechanism leading to pain at the lateral/posterolateral distal fibula
  • local swelling or pseudotumor
  • may be able to voluntarily dislocate and relocate the peroneal tendons
  • examination may show predisposing factors such as:
    • cavovarus hindfoot (always look for the subtle cavus foot)
    • lateral ligament instability
    • other factors include Charcot-Marie-Tooth disease, accessory peroneal muscles, enlarged peroneal tubercle and abnormal morphology of the fibula groove
  • apprehension or frank instability can be demonstrated with resisted dorsiflexion and eversion manoeuvres
  • passive compression test of dorsiflexion and eversion may also replicate the patient’s pain




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Mafulli 2006


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Reproduced from Orthobullets



Plain xrays

  • may show stigmata of previous sprains
  • hindfoot alignment
  • ankle fleck sign may be seen after avulsion of the superior peroneal retinaculum from the distal fibula


  • dynamic scanning will show subluxation
  • up to 90% sensitivity for picking up peroneal tendon tears
  • user dependant


  • bony morphology
  • mal-unions
  • impingment


  • very useful to detect tears
  • may show secondary injuries such as ATFL and CFL tears, osteochondral lesions
  • should be performed with the ankle in plantarflexion to reduce the change of angle in the peroneals as they come around the fibula



Non-operative management

  • 6 weeks of immobilisation has been described for acute tendon tears
  • has a high (50%+) failure rate

Operative intervention

  • depends on the underlying pathology found
  • may be tailored to deal with predisposing factors (e.g. varus hindfoot)

Partial tears

  • debridement alone (open or endoscopically)
  • debridement with tubularisation has improved outcomes (often defined a return to play)

Complete tears

  • PB tears can be treated by side-to-side tenodesis to peroneus longus
  • Tears to both tendons may necessitate FDL/FHL transfer, although eversion strength is likely to remain poor

Subluxing tendons

  • superior peroneal retinaculum can be repaired in isolation or along with…
  • groove deepening, giving a higher return to play but increased stiffness and stenosis
  • reflection of a lateral fibula periosteal flap can be utilised to reinforce the repair
  • other, more formal, osteotomy and soft tissue procedures are described (small numbers only); may be reserved for salvage/revision cases


  • period of immobilsation (e.g. 2 weeks in NWB cast, then 4 weeks WB in boot)
  • rehabilitation including peroneal strengthening and proprioception

Lootsma et al published a systematic review and meta-analysis of chronic peroneal tendon instability in 2023 that concluded that surgery gives high levels of success, although outcomes involving bony or re-routing surgery appeared inferior.


  • recurrence
  • sural nerve injury
  • ongoing pain / swelling

All interventions have a high failure rate if hindfoot alignment is not also corrected at the time of surgery



Diagnosis of peroneal tendon instability should be considered in young healthy patients presenting with dorsiflexion injuries in an inverted foot that complain of pain and a feeling of instability in the ankle.

Once confirmed, retinacular and tendon injuries can be treated operatively with high levels of success, especially when more simple repairs and tubularisation techniques are used.



Ferran, Nicholas & Oliva, Francesco & Maffulli, Nicola. (2006). Recurrent Subluxation of the Peroneal Tendons. Sports medicine (Auckland, N.Z.). 36. 839-46. 10.2165/00007256-200636100-00003.

Lootsma J, Wuite S, Hoekstra H, Matricali GA. Surgical treatment options for chronic instability of the peroneal tendons: a systematic review and proportional meta-analysis. Arch Orthop Trauma Surg. 2023 Apr;143(4):1903-1913. doi: 10.1007/s00402-022-04395-4. Epub 2022 Mar 9. PMID: 35260916.

Trache T, Camenzind RS, Bachmann E, Viehöfer A, Jud L, Wirth S, Imhoff FB. A Biomechanical Analysis of Peroneus Brevis Split Lesions, Repair, and Partial Resection. Foot Ankle Int. 2022 May;43(5):710-716. doi: 10.1177/10711007211069558. Epub 2022 Jan 24. PMID: 35073766.

Ahn BH, Cho BK. Persistent Pain After Operative Treatment for Chronic Lateral Ankle Instability. Orthop Res Rev. 2021 Apr 19;13:47-56. doi: 10.2147/ORR.S299409. PMID: 33907476; PMCID: PMC8064723.