Direct posterolateral approach to the fibula along the course of the peroneal tendons · advanced
- Peroneus brevis longitudinal split tears are the MOST COMMON lesion, occurring at the fibular tip from subclinical subluxation of the tendon over the posterolateral fibular ridge (the Krause-Brodsky mechanism).
- Superior Peroneal Retinaculum (SPR) insufficiency is the PRIMARY cause of peroneal subluxation — in acute injury the SPR most commonly avulses off its fibular insertion (Eckert-Davis Type I), rather than rupturing mid-substance.
- The Krause-Brodsky 50 percent rule drives the whole operation: under 50 percent of the cross-section with good tissue is debrided and tubularized; over 50 percent is excised and tenodesed to the intact tendon. An FHL/FDL transfer or allograft is SALVAGE only, for when both tendons are non-functional.
- Sural nerve injury is the MOST COMMON complication (around 5-15 percent). The nerve runs with the lesser saphenous vein roughly 1-2cm posterior to the lateral malleolus — find the vein, find the nerve, protect it from the first cut.
When & Why
Indication. Surgery is offered for symptomatic peroneal tendon pathology that has failed conservative management (a period of rest, bracing, physiotherapy and activity modification). The two broad indications are: - Tendon tears — a peroneus brevis longitudinal split tear involving over 50 percent of the cross-section, a partial or complete rupture of either tendon, or painful tendinosis with over 50 percent degeneration; acute complete ruptures in young athletic patients are repaired early.
- Peroneal subluxation or dislocation — symptomatic instability from SPR insufficiency or rupture, often with a shallow fibular groove (under 2mm depth), where bracing and physiotherapy have failed. Combined pathology is the rule, not the exception. Before committing, actively look for and plan to address: - Concurrent lateral ankle instability — ligamentous incompetence coexists with peroneal tears in around one third of operative cases (Dombek 2003), reflecting the shared inversion mechanism. If symptomatic instability is confirmed, address it at the same sitting with a Modified Brostrom-Gould.
- A shallow or convex fibular groove (under 2mm on axial MRI) — a key contributor to both subluxation and brevis impingement tears. SPR repair alone will fail if the groove is inadequate.
- An os peroneum fracture — pathognomonic of a peroneus longus rupture at the cuboid tunnel, which needs a different (plantar-lateral) exposure. Contraindications are active infection, severe peripheral vascular disease, an inadequate soft-tissue envelope, medical comorbidities precluding surgery, and a patient who will not comply with the postoperative restrictions. The reconstruction ladder — the one decision that matters. Whatever the final construct, the case begins the same way: expose the tendons, protect the sural nerve, open the sheath and assess the tear. The operation then branches on the Krause-Brodsky 50 percent rule:
Good-quality tissue (pink, firm, normal calibre) with a tear involving under 50 percent of the cross-section. Debride the degenerate split and tubularize with a running locked stitch. This is primary repair, and it does excellently.
Over 50 percent involved, poor tissue, or a complete rupture. Excise the irreparable segment and tenodese the stumps to the intact partner tendon over 2-3cm. This is the standard reconstruction for an isolated grade 2 tear.
When BOTH peroneal tendons are non-functional, or there is no usable proximal muscle excursion, move up the ladder: an FHL transfer (preferred) or FDL transfer, or a static allograft. Never the default for a single grade 2 tear.
Preoperative assessment. - History — lateral ankle pain and weakness, a sensation of snapping or popping with activity. An acute dorsiflexion-eversion injury with a pop suggests SPR rupture and subluxation; chronic lateral pain suggests tendinopathy or tears.
- Examination — palpate the tendons along the fibular groove for tenderness, swelling or palpable subluxation; perform the peroneal subluxation test (active dorsiflexion and eversion while palpating, feeling for tendons jumping anterior to the fibula); assess lateral stability with the anterior drawer and talar tilt.
- Imaging — AP, lateral and mortise radiographs assess the os peroneum, the fibular groove and ankle arthritis. MRI is essential for surgical planning: it defines the tear pattern (longitudinal split versus rupture), the degree of tendinosis, SPR integrity, and fibular groove morphology and depth. Ultrasound adds dynamic assessment of subluxation where available. Consent specifically for sural nerve numbness or a painful neuroma (the commonest nerve complication), wound problems, a small risk of recurrent tear or subluxation, stiffness, and the restricted weight-bearing and rehabilitation commitment. Counsel that good-to-excellent outcomes are reported in the majority across procedures (mean postoperative AOFAS around 82-90), with return to sport typically at 4-6 months. Setup. Lateral decubitus with the affected side up, on a bean-bag with an axillary roll and generous padding (protect the dependent peroneal nerve at the fibular neck). A thigh tourniquet inflated to 300mmHg after exsanguination. Prep the entire leg circumferentially to allow access to the lateral ankle, foot, and the medial side should a tendon transfer be needed. Mark the lateral malleolus, the palpable peroneal tendons in their groove, the approximate course of the sural nerve, and the calcaneofibular ligament.
The Operation
The goal: protect the sural nerve throughout, expose the retrofibular space and the SPR through a direct posterolateral approach, assess both tendons and the SPR, then choose the right operation on the Krause-Brodsky ladder — repair the tendon if under 50 percent, tenodese to the intact partner if over 50 percent, and address the underlying cause (SPR, groove, instability) so the reconstruction does not re-fail.
Operative sequence
- Mark a longitudinal incision 10-12cm long, centred over the lateral malleolus, extending about 6cm proximal to 4-6cm distal to the fibular tip.
- Place the line slightly posterior to the fibular tip, directly over the palpable peroneal tendons in their retrofibular groove — not over the subcutaneous fibula anteriorly, and not so far posterior that the tendons are missed.
- The curve allows proximal extension toward the muscle and distal extension to the cuboid if a longus lesion is found. This is a direct posterolateral approach to the fibula along the course of the tendons; the interval is between subcutaneous tissue and the peroneal tendon sheath (not a true internervous plane).
- Incise the skin sharply, then dissect carefully in the subcutaneous plane.
- Identify the sural nerve early — it runs with the lesser saphenous vein in the subcutaneous tissue, roughly 1-2cm posterior to the lateral malleolus. Find the vein first; the nerve is alongside it.
- Tag the nerve with a vessel loop and maintain gentle posterior retraction throughout the case. Preserve the lateral calcaneal branches, which branch toward the heel around 6-8cm proximal to the malleolus.
The sural nerve is the MOST COMMON structure injured here (5-15 percent), with variable anatomy that may include multiple branches. Identify it early by finding the lesser saphenous vein, tag it, and retract gently and posteriorly — excessive traction alone causes a neuropraxia. Lateral calcaneal branches course toward the heel and must be preserved.
- Identify the SPR as a fibrous band 2-4cm proximal to the fibular tip, spanning from the posterolateral fibula toward the lateral calcaneus.
- Assess its integrity: intact, attenuated, partially torn, or completely torn.
- If torn, classify by the Eckert-Davis system to plan fixation: Type I (SPR elevated from the fibula with tendons beneath a periosteal flap — the commonest acute lesion), Type II (fibrocartilaginous ridge avulsed with the SPR), Type III (cortical bone fragment avulsed), Type IV (posterior or calcaneal detachment).
- Tag torn edges for later repair. In subluxation cases the tendons may jump anterior to the fibula with ankle manipulation.
- Incise the peroneal tendon sheath longitudinally from proximal to distal and open it widely to expose both tendons throughout their length.
- Perform a synovectomy of inflamed synovium to improve visualization.
- Identify both tendons correctly: the peroneus brevis is ANTERIOR and SUPERFICIAL in the groove (it originates on the distal fibula and inserts at the base of the 5th metatarsal); the peroneus longus is POSTERIOR and DEEP (it originates on the proximal fibula, dives plantar at the cuboid, and inserts at the base of the 1st metatarsal and medial cuneiform). Confirm by tracing distally — the brevis stays superficial to the 5th metatarsal, the longus disappears plantarward at the cuboid.
Brevis is anterior (closer to the fibula) and superficial and is the tendon most commonly torn, at the fibular tip. Longus is posterior (toward the Achilles) and deep and tears at the os peroneum or cuboid tunnel. Confusing the two means operating on the wrong tendon.
- Systematically inspect both tendons along their entire exposed length for tears.
- Define the pattern: a longitudinal split (most common in brevis, like split book pages), a partial tear, or a complete rupture with a gap.
- Judge tissue quality: healthy tissue is pink, firm and of normal calibre; poor tissue is grey, friable, thin and degenerate.
- Measure the extent: under 50 percent of the cross-section with good tissue is a grade 1 lesion (primary repair); over 50 percent, poor tissue, or a complete rupture is grade 2 (reconstruction). Debride degenerate tissue back to healthy, bleeding edges before deciding.
Grade 1 (under 50 percent, good tissue): debride and tubularize. Grade 2 (over 50 percent, poor tissue, or rupture): excise the damaged segment and tenodese to the adjacent intact tendon (typically brevis to longus). Do NOT attempt to tubularize an over-50 percent tear — it has a high failure rate. A tendon transfer or allograft is reserved for when both tendons are non-functional.
- For a tear under 50 percent with good tissue, tubularize the longitudinal split with a side-to-side repair.
- Use a 2-0 or 3-0 absorbable suture in a running locked stitch (a Krackow gives the best strength; a baseball stitch is faster).
- Repair the entire length of the split, typically 4-6cm, restoring a smooth tubular contour without bunching or gaps and maintaining normal tendon tension.
- Test gliding in the fibular groove — the tendon should move smoothly without catching. If it catches, the repair is too bulky.
- Preferred — tenodesis to the intact tendon: when the other peroneal tendon is healthy (the usual situation), excise the irreparably damaged segment and tenodese the proximal and distal stumps side-to-side to the intact partner (e.g. brevis to longus) with multiple non-absorbable mattress sutures over 2-3cm. Re-examine the recipient tendon first — never tenodese onto a tendon that is itself diseased.
- Salvage — tendon transfer or allograft: reserved for the rare case where BOTH tendons are non-functional or there is no usable proximal excursion. FHL is favoured (larger, stronger, in-phase, lying adjacent in the deep posterior compartment); FDL is the alternative. Harvest through a separate medial incision, protecting the posterior tibial neurovascular bundle (behind the medial malleolus the order, anterior to posterior, is tibialis posterior, FDL, posterior tibial artery, tibial nerve, then FHL — the nerve is posterior to the artery). Secure to the base of the 5th metatarsal or fibula with a bone tunnel or 3.0-3.5mm interference/anchor fixation. Allograft (hamstring or Achilles) is the static option when no motor is available.
- Whatever the construct, tension in neutral, restoring eversion to match the contralateral side — too tight restricts motion, too loose gives weak eversion.
The examiner wants the ladder: under 50 percent, tubularize; over 50 percent with an intact partner, tenodese to it; both tendons gone but muscle excursion preserved, transfer (FHL preferred); no usable excursion, allograft. Reaching for a transfer for an isolated grade 2 brevis tear is wrong — the tenodesis is the correct, simpler operation.
- Assess groove depth (normal is over 2mm; a shallow or convex groove is under 2mm).
- If shallow, deepen the groove to remove the posterolateral bony ridge and improve tracking. Use a curved osteotome or burr to create a U-shaped groove about 4-5mm deep and 8-10mm wide, smooth all sharp edges, and irrigate copiously to remove bone debris.
- Avoid penetrating the anterior cortex (it violates the ankle joint and weakens the fibula). Reassess tendon tracking in the deepened groove.
A shallow groove (under 2mm) predisposes to both subluxation and brevis impingement tears, and systematic-review evidence shows combining groove deepening with SPR repair gives higher return-to-sport rates than SPR repair alone. The risk is fibular fracture if over-aggressive (rare, under 1 percent, but catastrophic), so limit depth to 4-5mm, preserve the anterior cortex, and use irrigation with intermittent burr contact to avoid thermal injury.
- For a grade 3 SPR tear, or a grade 2 tear with poor tissue, reconstruct the retinaculum.
- Direct repair (most common): place one or two 3.0mm suture anchors at the posterior fibular insertion, pass the sutures through the torn SPR, and tie with the ankle in neutral and slight eversion. Transosseous tunnels through the fibula are a traditional, hardware-free alternative.
- Augmentation (for poor-quality, chronic tissue): weave a local tissue strip (Achilles or peroneal sheath) through the native SPR and secure it to fibula and calcaneus.
- Bone block (rarely used now): elevate a posterior fibular cortical flap, rotate it over the tendons and secure it. Test stability — the tendons must remain posterior to the fibula through dorsiflexion and eversion.
Over-tightening restricts eversion and causes lateral pain; under-tightening allows persistent subluxation (a 10-15 percent failure rate). Tie the repair with the ankle neutral and slightly everted, then confirm the tendons cannot be dislocated anteriorly.
- If symptomatic instability was confirmed preoperatively (positive anterior drawer or talar tilt, stress radiographs, or ATFL/CFL deficiency on MRI), perform a Modified Brostrom-Gould in the same setting.
- Do the peroneal work first, then extend the same lateral incision anteriorly for ATFL access. Immobilize in neutral to protect both repairs. Combined procedures do not significantly increase the complication rate and have a success rate around 80-85 percent.
- Gliding test: plantarflex and dorsiflex the ankle and evert the foot — tendons should glide smoothly without catching or bunching.
- Stability test: dorsiflex and evert — tendons must remain posterior to the fibula, with no subluxation.
- Strength test: resist eversion manually and compare with the contralateral side.
- ROM test: full dorsiflexion, plantarflexion, inversion and eversion, with no restriction or pain.
- Persistent subluxation means inadequate SPR reconstruction or a shallow groove needing revision; restricted gliding means a bulky or over-tight repair; weak eversion means a loose transfer.
Testing under anaesthesia can give false reassurance from muscle relaxation, but major problems — persistent subluxation, a bulky repair, a loose transfer — are evident intraoperatively and are far easier to fix now than after closure.
- Close the tendon sheath loosely with 3-0 absorbable suture (simple interrupted) — a tight sheath closure causes adhesions and restricts gliding.
- Close the subcutaneous tissue with absorbable suture and the skin with nylon or a subcuticular absorbable. A drain is optional if there is significant dead space or bleeding risk.
- Apply a well-padded short leg splint with the ankle in neutral and slight eversion — the position that protects the repair.
Excessive plantarflexion or eversion overloads the repair; excessive dorsiflexion or inversion stresses it. Neutral with slight eversion is optimal. Non-weight-bearing for 2 weeks protects wound healing, then weight-bearing as tolerated in a CAM boot brings the total immobilization to about 6 weeks (tendon healing takes 6-8 weeks).
- Sural nerve — subcutaneous, 1-2cm posterior to the lateral malleolus with the lesser saphenous vein; the commonest injury (5-15 percent). Identify it early, tag it, retract posteriorly.
- Lateral calcaneal branches — branch from the sural nerve about 6-8cm proximally toward the heel; preserve them.
- Calcaneofibular ligament (CFL) — deep to the tendons, from the fibular tip to the calcaneus; avoid excessive anterior dissection during SPR and groove work.
- Peroneal artery — deep to the tendons in the posterior compartment, roughly 2-3cm anterior to the fibula proximally; stay within the tendon sheath plane and avoid deep anterior dissection.
- Posterior fibular cortex — a thin wall that can be violated by over-aggressive groove deepening; limit deepening to 4-5mm and preserve the anterior cortex.
- The problem
- Painful os peroneum or longus rupture in the cuboid tunnel (os peroneum present in around 20 percent)
- The surgical answer
- Separate plantar-lateral incision over the cuboid; protect sural branches; remove painful fragments; if the longus is non-reconstructible, perform a longus-to-brevis tenodesis
- The problem
- ATFL/CFL incompetence — coexists in around one third of operative cases
- The surgical answer
- Same sitting: peroneal repair first, then Modified Brostrom-Gould through the same incision extended anteriorly
- The problem
- Degenerate, swollen tendon, usually under 50 percent of the cross-section
- The surgical answer
- Conservative debridement plus synovectomy; groove deepening and SPR work if indicated; do not over-debride into a tear
- The problem
- Re-tear or persistent subluxation after prior surgery
- The surgical answer
- Protect the sural nerve (higher risk in scarred tissue); allograft or longus-to-brevis if native tissue is poor; address groove, SPR and instability; lower success (70-75 percent)
Aftercare & Complications
Rehabilitation | Phase | Timing | Immobilisation | Therapy | |-------|--------|----------------|---------| | 1 — Protection | 0-2 weeks | Well-padded short leg splint, ankle neutral with slight eversion; non-weight-bearing; elevation | None — wound healing and swelling control | | 2 — Progressive weight-bearing | 2-6 weeks | CAM boot; weight-bearing as tolerated; removed only for wound care and gentle ankle pumps | Ankle pumps only; no inversion/eversion yet; protect tendon healing | | 3 — Range of motion | 6-8 weeks | Discontinue the boot; ankle brace or lace-up support for 2-4 weeks | Formal physiotherapy — gentle ROM in all planes; proprioception; no resistance | | 4 — Strengthening | 8-12 weeks | Brace for heavy tasks only | Progressive theraband (focus on eversion); heel and toe raises; continue proprioception | | 5 — Return to activity | 3-6 months | Prophylactic brace for sport initially | Sport-specific drills at 3 months; straight-line running then cutting; full return by 4-6 months | Most patients return to sport by 4-6 months depending on the procedure. Across published series, debridement and primary repair of grade 1 tears gives good-to-excellent results in the majority (mean postoperative AOFAS around 85-90), and reconstruction of grade 2 tears gives reliable functional improvement (AOFAS around 82-85). Surgery for subluxation has high satisfaction and a low long-term redislocation rate (under 1.5 percent); combining groove deepening with SPR repair gives significantly higher return-to-sport rates than SPR repair alone. Complications
- Recognition
- Lateral foot numbness, dysaesthesia, painful neuroma; positive Tinel at the scar
- Prevention
- Identify early via the lesser saphenous vein; tag and retract gently posteriorly; avoid traction and nearby cautery
- Management
- Most neuropraxias settle by 3-6 months; persistent neuroma — desensitisation, nerve blocks, then excision with burial into muscle
- Recognition
- Return of lateral pain, weakness and swelling after initial improvement; MRI confirms re-tear, often after premature return to activity
- Prevention
- Correct repair selection (tenodese over-50 percent tears, do not tubularize); adequate immobilisation; gradual rehabilitation
- Management
- Revision — tenodesis if a healthy partner remains, else transfer or allograft; re-address the biomechanical cause; outcomes less reliable in revision
- Recognition
- Snapping or popping over the lateral ankle; visible subluxation anterior to the fibula on eversion/dorsiflexion; MRI shows SPR insufficiency
- Prevention
- Adequately tensioned SPR repair PLUS groove deepening for a shallow groove; avoid early mobilisation; confirm intraoperative stability
- Management
- Revision SPR reconstruction with augmentation; groove deepening if not done initially; bone block for severe cases
- Recognition
- Restricted ROM, especially dorsiflexion and eversion; pain at end-range
- Prevention
- Avoid tight sheath closure; right-length immobilisation; early ROM at 6 weeks
- Management
- Aggressive physiotherapy and manual therapy; arthroscopic or open adhesiolysis at 6-plus months if adhesions confirmed
- Recognition
- Dehiscence, drainage, erythema, warmth; superficial versus deep infection
- Prevention
- Meticulous haemostasis; layered tension-free closure; 2 weeks non-weight-bearing; optimise smoking and diabetes
- Management
- Superficial — oral antibiotics and wound care; deep — washout and IV antibiotics, retain hardware if possible; dehiscence — local care and delayed closure
- Recognition
- Disproportionate pain, swelling, colour and temperature change, allodynia (Budapest criteria)
- Prevention
- Minimise surgical trauma and tourniquet time; adequate analgesia; early motion when appropriate
- Management
- Early recognition; desensitisation physiotherapy; neuropathic agents; sympathetic blocks; vitamin C 500mg daily
- Recognition
- Weak eversion despite surgery; pain at the repair/transfer site; MRI shows pull-apart, elongation or pullout
- Prevention
- Tenodese only to a genuinely healthy partner over adequate length; for a transfer, harvest adequate length with strong fixation and tension in neutral
- Management
- If tenodesis fails, salvage with transfer or allograft; if a transfer fails, revise with allograft; always re-address groove, SPR and instability
Viva & Exam Focus
BREVISBREVIS — assessing a longitudinal split tear
SURALSURAL — protecting the sural nerve
Location: subcutaneous, with the lesser saphenous vein, 1-2cm posterior to the lateral malleolus. Protection: identify early via the vein, tag with a vessel loop, retract gently posteriorly throughout.
Location: branch from the sural nerve about 6-8cm proximal to the lateral malleolus, coursing toward the heel. Protection: preserve during subcutaneous dissection; gentle retraction if encountered.
Location: deep to the peroneal tendons, from the fibular tip to the lateral calcaneus. Protection: avoid excessive dissection anterior to the tendons during SPR reconstruction and groove deepening.
Location: deep to the tendons in the posterior compartment, roughly 2-3cm anterior to the fibula proximally. Protection: stay within the tendon sheath plane; avoid deep dissection anterior to the tendons.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 32-year-old basketball player presents with lateral ankle pain and a recurrent popping sensation. Describe your diagnostic approach and how you would decide between repair and reconstruction.”
“You are performing peroneal tendon repair and identify a longitudinal split tear involving 60 percent of the peroneus brevis. Walk me through your surgical management and technical decision-making.”
“During peroneal tendon surgery you encounter brisk bleeding from what appears to be the peroneal artery. Describe your immediate management and how you prevent this complication.”
Indications
- Brevis longitudinal split tears (the commonest lesion) with over 50 percent involvement or failed conservative care
- Tendon rupture (brevis or longus) with inadequate tissue for primary repair
- Symptomatic subluxation/dislocation from SPR insufficiency or a shallow groove (under 2mm)
- Severe tendinosis with over 50 percent degeneration, or an os peroneum fracture with longus rupture
- Concurrent symptomatic lateral ankle instability needing a combined reconstruction
Key anatomy
- Brevis: ANTERIOR and SUPERFICIAL in the groove, inserts at the base of the 5th metatarsal, the commonest tear
- Longus: POSTERIOR and DEEP, courses plantar to the cuboid, inserts at the base of the 1st metatarsal/medial cuneiform
- SPR: the PRIMARY restraint to subluxation, acutely avulsed off the fibula (Eckert-Davis I-III)
- Fibular groove: normal depth over 2mm; under 2mm predisposes to subluxation and impingement
- Sural nerve: 1-2cm posterior to the lateral malleolus with the lesser saphenous vein
Critical steps
- Step 1: identify and protect the sural nerve early (5-15 percent injury rate)
- Step 2: open the sheath widely; identify both tendons; synovectomy
- Step 3: assess the tear — under 50 percent, repair; over 50 percent, tenodese to the intact tendon
- Step 4: tubularize with a running locked stitch (Krackow/baseball); test gliding
- Step 5: tenodese over-50 percent tears; transfer/allograft only when both tendons are lost; tension in neutral
- Step 6: SPR reconstruction with suture anchors, tensioned in neutral/slight eversion
- Step 7: groove deepening if shallow (under 2mm), to 4-5mm, avoid the anterior cortex
- Step 8: intraoperative testing of gliding, stability, strength and ROM before closure
Danger zones
- Sural nerve: 1-2cm posterior to the lateral malleolus with the lesser saphenous vein
- Lateral calcaneal branches: branch about 6-8cm proximally toward the heel
- CFL: deep to the tendons, fibular tip to calcaneus
- Peroneal artery: roughly 2-3cm anterior to the fibula, deep to the tendons
- Posterior fibular cortex: limit groove deepening to 4-5mm; avoid fracture
Decision pearls
- Krause-Brodsky 50 percent rule: tubularize if under 50 percent AND good tissue; tenodese if over 50 percent
- Brevis (anterior/superficial, commonest tear at the fibular tip) versus longus (posterior/deep, tears at the os peroneum)
- SPR is the primary restraint, acutely avulsed (Eckert-Davis); chronic attenuated tissue needs augmentation
- Reconstruction ladder: tenodese to the intact tendon first; transfer/allograft is SALVAGE only
- Shallow groove (under 2mm) may need deepening; combining it with SPR repair improves return-to-sport
- Concurrent lateral instability is common — address with a Modified Brostrom-Gould
Complications
- Sural nerve injury (5-15 percent): the commonest complication — prevent with early identification
- Recurrent tear: from wrong repair selection or premature return to activity
- Recurrent subluxation: low after adequate surgery (under 1.5 percent), rises if groove/SPR inadequately addressed
- Ankle stiffness/loss of eversion: from tight sheath closure or over-tight repair
- Wound complications, CRPS, reconstruction failure, fibular fracture (rare, from over-aggressive deepening)
Post-op protocol
- Phase 1 (0-2 weeks): splint in neutral with slight eversion, NWB
- Phase 2 (2-6 weeks): CAM boot, WBAT, ankle pumps only
- Phase 3 (6-8 weeks): boot off; gentle ROM all planes; proprioception
- Phase 4 (8-12 weeks): progressive strengthening, focus on eversion
- Phase 5 (3-6 months): sport-specific at 3 months; full return by 4-6 months
Exam tips
- Know the 50 percent rule cold — the critical decision point
- Distinguish brevis from longus — examiners test it
- SPR is the primary restraint, acutely avulsed (Eckert-Davis); chronic tissue needs augmentation
- Sural nerve is most at risk — know its anatomy and protection strategy
- Know the reconstruction ladder and that transfer/allograft is salvage only
- Shallow groove (under 2mm) may need deepening (4-5mm) — beware fibular fracture
- Immobilize in neutral with slight eversion; NWB 2 weeks, then WBAT in a boot to 6 weeks
Background & Evidence
Anatomy. The two peroneal tendons share a fibrous retromalleolar groove on the posterior fibula, bounded by the superior peroneal retinaculum (SPR) — a fibrous band from the posterolateral fibula toward the lateral calcaneus, 2-4cm proximal to the fibular tip, and the primary restraint to subluxation. In the groove the peroneus brevis lies anterior and superficial (originating on the distal fibula, inserting at the base of the 5th metatarsal); the peroneus longus lies posterior and deep (originating on the proximal fibula, coursing plantar through the cuboid tunnel to insert at the base of the 1st metatarsal and medial cuneiform). Both are primary ankle evertors and dynamic lateral stabilisers. The sural nerve runs subcutaneously with the lesser saphenous vein about 1-2cm posterior to the lateral malleolus (its lateral calcaneal branches head toward the heel 6-8cm proximally), and the peroneal artery lies deep in the posterior compartment roughly 2-3cm anterior to the fibula. Pathophysiology — why the brevis tears at the fibular tip. Krause and Brodsky showed that subclinical or overt subluxation of the brevis over a shallow posterolateral fibular ridge produces repetitive impingement and friction, generating the characteristic multiple longitudinal splits. The same shallow or convex groove (under 2mm depth) that predisposes to impingement also predisposes to overt subluxation when the SPR fails — which is why the cause, not just the tear, must be addressed.
- Pattern
- SPR elevated/avulsed off the fibula, with the tendons beneath a periosteal or fibrocartilaginous flap
- Implication
- The commonest acute lesion; anatomical repair back to the fibula
- Pattern
- Fibrocartilaginous ridge avulsed together with the SPR
- Implication
- Repair back to the fibula, often with the bone/ridge
- Pattern
- Cortical bone fragment avulsed with the SPR
- Implication
- Anatomical bony re-fixation
- Pattern
- SPR torn from its posterior or calcaneal attachment
- Implication
- The rarest pattern; direct repair of the posterior attachment
- Tear extent
- Under 50 percent of the cross-section, with good tissue (pink, firm, normal calibre)
- Operation
- Debride the degenerate split and tubularize (running locked stitch)
- Tear extent
- Over 50 percent of the cross-section, poor tissue, or a complete rupture
- Operation
- Excise the damaged segment and tenodese to the intact peroneal tendon
- Tear extent
- Both tendons non-functional, or no usable proximal muscle excursion
- Operation
- FHL (preferred) or FDL transfer, or a static allograft
Epidemiology. Peroneal tendon tears are most common in the peroneus brevis at the fibular tip. They are seen in athletes (recurrent inversion/eversion loading) and in middle-aged patients, and frequently coexist with lateral ankle ligament incompetence (around one third of operative cases, Dombek 2003). An os peroneum is present in roughly 20 percent of the population and, when fractured, is pathognomonic of a peroneus longus rupture at the cuboid tunnel. Guidelines, registries & global practice. There is no single dominant national guideline for peroneal tendon surgery; practice is driven by the foot-and-ankle literature and is broadly consistent across AOFAS (US), BOFAS/BOA (UK), EFAS (Europe) and equivalent bodies. The Krause-Brodsky classification and the 50 percent rule are the universally taught framework. For subluxation and dislocation the worldwide consensus is anatomical SPR repair (with the Eckert-Davis pattern guiding fixation) combined with retromalleolar groove deepening for shallow grooves, supported by systematic-review evidence (van Dijk 2016). For irreparable single-tendon tears, tenodesis to the intact tendon is the global default; FHL/FDL transfer and allograft are salvage options used variably by region according to surgeon preference and graft availability. No billing or coding content is included, as it is not relevant to exam practice and varies by jurisdiction.
References
Peroneus brevis tendon tears: pathophysiology, surgical reconstruction, and clinical results
- Defined the mechanism: subclinical or overt subluxation of the brevis over the posterolateral fibular ridge produces multiple longitudinal splits
- Proposed the operative classification still used today — Grade 1 (under 50 percent cross-section): debride and repair; Grade 2 (over 50 percent): excise the damaged segment and tenodese to the peroneus longus
- Stressed that BOTH the split tendon and the causative subluxation (SPR/groove stabilisation) must be addressed
- Average postoperative AOFAS 85 with good-to-excellent results in the majority
Operative treatment for peroneal tendon disorders
- Comprehensive operative review: MRI is the standard imaging, but diagnosis and treatment rest primarily on history and examination
- Tenosynovitis usually responds to conservative care; operative treatment is reserved for refractory cases
- Subluxation is treated by anatomical repair/reconstruction of the SPR with or without retromalleolar groove deepening
- Reaffirmed the 50 percent rule: primary repair and tubularization for tears under 50 percent, tenodesis for tears over 50 percent
Return to sports and clinical outcomes in patients treated for peroneal tendon dislocation: a systematic review
- Systematic review of 14 studies of surgically treated peroneal tendon dislocation
- Surgery improved AOFAS scores significantly with high satisfaction and quick return to sport
- Long-term redislocation rate was under 1.5 percent
- Combined groove deepening PLUS SPR repair gave significantly higher return-to-sport rates than SPR repair alone (p = 0.022)
Long-term results of debridement and primary repair of peroneal tendon tears
- Cohort of 34 patients with debridement and primary repair; 18 with mean 6.5-year follow-up
- VAS pain fell from a mean of 39 to 10 and LEFS rose from 45 to 71 (both p less than 0.001)
- 17 of 18 responders returned to full sporting activity without limitation
- No reoperations or operative failures over the follow-up interval
Peroneal tendon injuries: an evaluation of 49 tears in 41 patients
- Prospective evaluation of 49 peroneal tears (31 brevis, 18 longus) in 41 patients
- Mean AOFAS improved from 52 preoperatively to 89.7 postoperatively (p less than 0.00001)
- No significant difference in return to activity or AOFAS between longus, brevis and combined tears
- 14 of 16 athletes returned to full sporting level; mean return to activity around 3.5 months
Peroneal tendon tears: a retrospective review
- Retrospective review of operatively treated peroneal tendon tears
- Reported that concurrent lateral ankle ligamentous incompetence coexisted with peroneal tears in around one third of operative cases, reflecting the shared inversion mechanism
The management of concomitant tears of the peroneus longus and brevis tendons
- Algorithm for the management of concomitant longus and brevis tears
- Mean postoperative AOFAS 82, with 91 percent achieving normal or moderate peroneal strength in combined tears
Further reading - Steel MW, DeOrio JK. Peroneal tendon tears: return to sports after operative treatment. Foot Ankle Int. 2007;28(1):49-54. doi:10.3113/FAI.2007.0009
- Philbin TM, Landis GS, Smith B. Peroneal tendon injuries. J Am Acad Orthop Surg. 2009;17(5):306-317. doi:10.5435/00124635-200905000-00005
- Roster B, Michelier P, Giza E. Peroneal tendon disorders. Clin Sports Med. 2015;34(4):625-641. doi:10.1016/j.csm.2015.06.003
- Karlsson J, Eriksson BI, Renstrom PA. Subtalar ankle instability: a review. Sports Med. 1997;24(5):337-346. doi:10.2165/00007256-199724050-00005