Peroneal Tendon Repair & Groove Deepening

Indications

Absolute Indications

• Recurrent peroneal tendon subluxation/dislocation with documented SPR insufficiency
• Symptomatic longitudinal peroneal tendon tear (>50% width) with failed conservative management (3-6 months)
• Acute complete SPR rupture in high-demand athletes/military personnel
• Peroneal tendon dislocation with associated avulsion fracture requiring fixation

Relative Indications

• Chronic peroneal tenosynovitis refractory to conservative treatment
• Peroneal tendon tear <50% width with mechanical symptoms
• Shallow retromalleolar groove (<5mm depth) with symptomatic subluxation
• Failed prior conservative management: PT, bracing, activity modification, injections

Contraindications

Absolute:

• Active infection overlying surgical site
• Severe peripheral vascular disease with inadequate perfusion
• Medical comorbidities prohibiting surgery

Relative:

• Uncontrolled diabetes with poor wound healing potential
• Heavy tobacco use (increases wound complications)
• Poor patient compliance with post-operative restrictions
• Significant ankle arthritis requiring different surgical approach
• Neuropathic ankle (Charcot risk)

Pre-operative Assessment

Clinical Examination

• Inspection: Swelling posterior to lateral malleolus, ecchymosis, visible/palpable subluxation
• Palpation: Tenderness over tendons, palpable tendon subluxation with circumduction
• Provocative tests: Ankle dorsiflexion + eversion reproduces subluxation, resisted eversion pain
• Stability assessment: Anterior drawer, talar tilt for associated lateral ligament injury
• Functional testing: Single leg heel raise, toe walking, lateral foot sensation (sural distribution)

Imaging Protocol

• Weight-bearing radiographs: AP, lateral, mortise ankle; AP, lateral foot - assess os peroneum, avulsion fractures
• MRI ankle: Axial sequences critical - assess tendon tears, tenosynovitis, SPR integrity, groove depth
• Ultrasound: Dynamic assessment of subluxation, real-time tendon tracking (operator-dependent)
• CT scan: If considering groove deepening - measure retromalleolar groove depth (<5mm = shallow)

Key MRI Findings

• Tendon pathology: T2 hyperintensity (tendinosis), longitudinal split (tram-track sign), complete tear
• SPR status: Torn/absent SPR, attenuated retinaculum, abnormal fluid signal
• Groove anatomy: Flat/convex retromalleolar groove, <5mm depth measurement
• Associated findings: Ankle effusion, bone marrow edema lateral malleolus, os peroneum

Surgical Planning Considerations

Procedure Selection Matrix

• Subluxation + shallow groove: Groove deepening + SPR repair/reconstruction
• Subluxation + normal groove: SPR repair/reconstruction alone (consider bone tunnel technique)
• Tendon tear <50%: Debridement + tubularization ± SPR repair
• Tendon tear >50%: Debridement + side-to-side repair OR tendon transfer (FDL/FHL)
• Complete rupture both tendons: Reconstruction with allograft ± tendon transfer

Equipment Checklist

• Standard soft tissue instrument set
• High-speed burr with rounded burrs (groove deepening)
• Suture anchors: 2-3 x 3.0-3.5mm for SPR repair
• 2-0/3-0 non-absorbable suture (SPR repair)
• 3-0/4-0 absorbable suture (tendon repair, tubularization)
• Vessel loops (nerve protection)
• Thigh tourniquet
• Fluoroscopy (confirm os peroneum, assess perforation risk)

Patient Positioning Strategy

• Preferred: Lateral decubitus with affected side up - optimal visualization, gravity assists exposure
• Alternative: Supine with bump under ipsilateral hip - easier anesthesia access, can assess both ankles
• Tourniquet: Thigh tourniquet 250-300mmHg
• Padding: All bony prominences, axillary roll if lateral, well-leg stirrup if supine

Step-by-Step Technique

Step 1: Positioning & Marking

Technique: Position patient lateral decubitus (affected side up) or supine with bump under ipsilateral hip. Apply and prepare thigh tourniquet. Mark surgical anatomy: (1) Lateral malleolus tip, (2) Peroneal tendon course (posterior to fibula), (3) Sural nerve course (18mm posterior to fibula tip), (4) Incision - curvilinear 6-8cm centered on lateral malleolus.

Step 2: Incision & Sural Nerve Identification

Technique: Curvilinear incision centered on lateral malleolus, 4cm proximal extending 2-4cm distal. Sharp dissection through skin only. Create full-thickness skin flaps carefully - avoid thin flaps over lateral malleolus. Identify sural nerve and lesser saphenous vein in posterior subcutaneous tissue. Protect with vessel loops. Gentle retraction throughout case.

Step 3: SPR Incision & Peroneal Tendon Exposure

Technique: Identify superior peroneal retinaculum (SPR) - fibrous band overlying retromalleolar groove. In chronic subluxation, SPR often torn or attenuated. Incise SPR LONGITUDINALLY at midline, creating superior and inferior flaps for later repair. Expose both peroneal tendons in retromalleolar groove. Note tendon position, quality, and pathology.

Step 4: Dynamic Tendon Assessment & Pathology Identification

Technique: Inspect both tendons carefully. Peroneus brevis (ANTERIOR) - check for longitudinal tears (C-shaped split), tenosynovitis, degenerative changes. Peroneus longus (POSTERIOR) - assess for tears, os peroneum pathology, intratendinous ganglion. Perform dynamic examination: plantar/dorsiflex and invert/evert ankle while observing tendon tracking and subluxation.

Step 5: Tendon Debridement & Repair

Technique:

• Tear <50% width: Debride frayed edges, tubularize with running 3-0/4-0 absorbable suture (side-to-side repair)
• Tear >50% width: Debride non-viable tissue, repair side-to-side to adjacent intact tendon OR consider allograft augmentation
• Severe degeneration >75%: Excise diseased tendon, tenodesis brevis to longus OR FDL/FHL transfer
• Aggressive synovectomy - remove all inflamed synovium to prevent recurrence

Step 6: Retromalleolar Groove Deepening

Technique: For recurrent subluxation with shallow groove (<5mm depth): Use high-speed burr with rounded tip. Remove cancellous bone from posterior fibular surface, creating smooth curved groove 3-5mm deeper. Create U-shaped channel. CRITICAL: Maintain 3-4mm of anterior (lateral) cortex - frequent palpation to avoid perforation. Smooth all edges with burr. Test tendon tracking - should remain in groove with full ROM.

Step 7: Superior Peroneal Retinaculum Repair/Reconstruction

Technique: SPR repair is ESSENTIAL. Multiple techniques available:

Option 1 - Direct Imbrication (intact SPR):

• Advance inferior SPR flap posteriorly and superiorly
• Overlap and suture to superior flap with 2-0 non-absorbable suture
• Creates doubled, tensioned restraint

Option 2 - Bone Tunnel Technique (preferred for chronic cases):

• Create 3-5mm bone tunnel in posterior fibula 1cm proximal to tip
• Pass SPR through tunnel
• Secure with suture anchor or transosseous sutures
• Provides mechanical advantage and robust fixation

Option 3 - Augmentation (poor tissue quality):

• Harvest lateral strip of Achilles tendon (3-4mm width) OR use allograft
• Weave through bone tunnel or anchor to fibula
• Supplement native SPR repair

Position ankle in NEUTRAL dorsiflexion, SLIGHT EVERSION during repair to avoid over-tensioning.

Step 8: Final Dynamic Stability Testing

Technique: Before closure, perform comprehensive dynamic assessment. Deflate tourniquet (if hemostasis adequate) or test with tourniquet up. Plantar/dorsiflex ankle fully. Invert/evert ankle fully. Observe tendon tracking through ROM - tendons should remain stable in groove without subluxation. If subluxation persists, reassess: (1) Groove depth adequate? (2) SPR repair too loose? (3) Need augmentation?

Step 9: Hemostasis & Layered Closure

Technique: Achieve meticulous hemostasis - bipolar cautery for vessels, avoid excessive cautery near sural nerve. Irrigate thoroughly with normal saline. Close deep fascia over tendons with 2-0 absorbable if tissue quality allows (not mandatory). Subcutaneous layer with 3-0 absorbable interrupted/running suture. Skin closure: 3-0/4-0 absorbable subcuticular OR 3-0 nylon interrupted. Apply sterile dressing with moderate compression.

Step 10: Immobilization & Post-operative Protection

Technique: Apply well-padded short leg splint or CAM walker boot. Position ankle in SLIGHT EVERSION (5-10°) and NEUTRAL dorsiflexion. Slight eversion protects SPR repair by reducing tension. Apply compressive dressing to minimize swelling. Elevate leg post-operatively. Non-weight-bearing initially.

Complication Rates by Procedure Type

Risk Factor Mitigation

High-Risk Patient Factors:

• Diabetes: Poor wound healing (15% vs 5% wound complications)
• Smoking: Increased wound complications (12% vs 5%), decreased healing
• Obesity: Wound complications, longer immobilization
• Neuropathy: Increased CRPS risk, compliance issues
• Prior surgery: Sural nerve injury risk doubled, scar tissue complicates dissection

Surgical Technique Factors:

• Incision placement: Too posterior = nerve injury, too anterior = exposure difficulty
• SPR repair quality: Inadequate = 30% recurrence vs <10% with robust repair
• Groove deepening: Perforation or fracture from excessive burring
• Hemostasis: Poor = hematoma = infection/CRPS risk

Immediate Post-operative (0-2 Weeks)

Week 0-2: Protection Phase

Immobilization:

• Short leg splint or CAM walker boot
• Position: Slight eversion (5-10°), neutral dorsiflexion
• Non-weight-bearing with crutches

Wound Care:

• Keep dressing dry and intact
• Elevate leg above heart level - reduce swelling
• Ice therapy: 20 minutes every 2-3 hours
• Monitor for complications: excessive pain, numbness, wound drainage

Pain Management:

• Multimodal analgesia: paracetamol + NSAID (if no contraindication)
• Opioids for breakthrough pain (limit duration)
• Neuropathic pain agents if sural nerve symptoms

DVT Prophylaxis:

• Early mobilization of non-operative joints
• Ankle pumps (toes/foot if comfortable)
• Consider pharmacological prophylaxis if high-risk (prior VTE, thrombophilia, prolonged immobilization expected)

First Post-operative Visit (10-14 days):

• Remove sutures (if non-absorbable used)
• Wound assessment
• Transition to removable CAM boot if wound healed
• Continue NWB

Early Rehabilitation (2-6 Weeks)

Week 2-4: Early Motion Phase

Weight-Bearing Progression (individualized):

• Tendon repair only: Begin PWB week 2-3
• Groove deepening + SPR repair: NWB until week 4
• Progress 25% body weight per week as tolerated

Range of Motion:

• Begin gentle active-assisted ROM week 4
• Plantar/dorsiflexion in boot (remove for exercises)
• Avoid inversion - stresses SPR repair
• Start with 10-15° arc, progress as tolerated

Modalities:

• Continue ice after exercises
• Compression stockings if significant swelling
• Gentle soft tissue mobilization around incision (week 3+)

Precautions:

• NO forceful inversion or eversion
• Maintain boot protection during ambulation
• Limit prolonged dependent positioning

Intermediate Rehabilitation (6-12 Weeks)

Week 6-8: Strengthening Initiation

Weight-Bearing:

• Progress to full weight-bearing in boot (week 6)
• Transition out of boot to supportive shoe (week 8) if ROM adequate and pain controlled

Range of Motion:

• Progressive active ROM all planes
• Goal: Full dorsiflexion, plantarflexion by week 8
• Eversion/inversion: progress cautiously

Strengthening:

• Isometric exercises: eversion, inversion, plantar/dorsiflexion
• Resistance band exercises (light resistance)
• Focus on peroneal strengthening - critical for function
• Intrinsic foot strengthening

Proprioception:

• Single leg stance (begin week 8)
• Balance board exercises (stable surface first)

Week 8-12: Functional Strengthening

Advanced Strengthening:

• Progressive resistance exercises
• Calf raises (bilateral → single leg)
• Peroneal strengthening with resistance bands (progressive resistance)
• Eccentric exercises

Proprioception & Balance:

• Unstable surface training (wobble board, BOSU)
• Sport-specific balance drills
• Perturbation training

Gait Training:

• Normal gait mechanics
• Uneven surface walking
• Incline/decline walking
• Stair negotiation

Return to Activity:

• Low-impact activities (swimming, cycling) at week 10
• Progress as strength and ROM improve

Late Rehabilitation (3-6 Months)

Month 3-4: Sport-Specific Training

Advanced Strengthening:

• Plyometric exercises (hopping, jumping)
• Sport-specific resistance training
• Continue peroneal and calf strengthening

Agility & Conditioning:

• Cutting and pivoting drills
• Figure-8 running
• Cone drills
• Sport-specific movement patterns

Criteria for Return to Sport (typically 4-6 months):

• Full pain-free ROM
• Peroneal strength >85% contralateral side
• Single leg hop test >90% contralateral
• Negative apprehension with eversion/inversion
• Sport-specific functional testing passed

Bracing:

• Consider lace-up ankle brace for sports initially (3-6 months)
• Gradual weaning as confidence and stability improve

Month 4-6: Return to Full Activity

Maintenance:

• Continue strengthening 2-3x/week
• Proprioception exercises ongoing
• Monitor for recurrent symptoms

Expected Outcomes:

• 85-90% good to excellent results with combined groove deepening + SPR repair
• 10-15% have residual symptoms (mild pain, subjective instability)
• Return to sport: 85-90% at pre-injury level by 6 months

Red Flags Requiring Urgent Assessment

• Sudden increase in pain with swelling (fracture, DVT, infection)
• Fever, wound drainage, increasing erythema (infection)
• Palpable/visible tendon subluxation (repair failure)
• Disproportionate pain, color changes, allodynia (CRPS)
• Calf swelling, tenderness, positive Homan's (DVT)
• Numbness or paresthesias worsening (nerve injury)

Long-term Follow-up

• 6 weeks: Clinical + radiographs (if groove deepening performed)
• 3 months: Assess ROM, strength, return to activity planning
• 6 months: Functional assessment, return to sport clearance
• 1 year: Final outcome assessment, patient satisfaction

Key Evidence

Surgical Technique Studies

Groove Deepening + SPR Repair (Steel et al. 2013):

• Combined procedure: 87% good/excellent results at 3 years
• Groove deepening alone: 58% success rate (p<0.001)
• Conclusion: SPR repair ESSENTIAL for successful outcome

SPR Reconstruction Techniques (Dallinga et al. 2014):

• Bone tunnel technique: 91% satisfaction, 8% recurrence
• Direct imbrication: 78% satisfaction, 18% recurrence
• Endoscopic approach: Equivalent outcomes, faster recovery (conflicting evidence)

Tendon Transfer for Severe Tears (Redfern & Myerson 2004):

• FDL transfer: 82% good/excellent outcomes
• Side-to-side repair >50% tears: 65% success rate
• Indications: >75% tendon loss, failed prior repair

Anatomical Studies

Sural Nerve Location (Webb et al. 2000):

• Average 18mm posterior to lateral malleolus (range 11-25mm)
• 8% of cases nerve within 11mm (high-risk zone)
• Implications: Wide variation - careful dissection essential

Retromalleolar Groove Morphology (Bonnin et al. 2016):

• Normal groove depth: 5-8mm
• Shallow groove <5mm associated with subluxation (OR 4.2)
• Flat/convex groove: 78% had clinical subluxation

Outcome Studies

Patient-Reported Outcomes:

• AOFAS Hindfoot Score: Pre-op 58 → Post-op 86 (p<0.001)
• VAS pain: Pre-op 6.8 → Post-op 1.9 (p<0.001)
• Return to sport: 85-90% at pre-injury level (6-12 months)
• Satisfaction rate: 87-92% with combined procedures

Complication Rates (Meta-analysis, Roster et al. 2015):

• Sural nerve injury: 5-10% (most neuropraxia, resolve 3-6 months)
• Recurrent subluxation: 5-15% (inadequate SPR repair main cause)
• Wound complications: 5-8% (higher in diabetics, smokers)
• Ankle stiffness: 10-20% (improves with PT)

Predictors of Outcome

Good Prognosis Indicators:

• Acute injury (<6 months): Better outcomes than chronic
• Isolated subluxation: Better than subluxation + tear
• Adequate SPR tissue: Better repair quality
• Patient compliance: Essential for post-op protocol

Poor Prognosis Indicators:

• Revision surgery: 20-30% worse outcomes vs primary
• Smoking: Increased wound complications (RR 2.4)
• Chronic subluxation >2 years: Lower satisfaction scores
• Poor SPR quality: Higher recurrence rate (25% vs 8%)

Australian Context

Medicare MBS Items

• 50327: Repair of ruptured tendon, ankle/foot = $458.65
• 50345: Tendon reconstruction with graft/transfer = $610.20
• 50357: Repair of recurrent tendon dislocation = $610.20
• Combined procedures may qualify for multiple item billing (check MBS rules)

PBS Medications

• Paracetamol + Codeine (30/500mg): First-line post-op analgesia
• Celecoxib 200mg BD: NSAID if no contraindications (funded for post-op pain short-term)
• Pregabalin 75-150mg BD: If neuropathic symptoms (sural nerve injury) - Authority required for chronic use

Evidence-Based Guidelines

• NHMRC Level II Evidence: Groove deepening + SPR repair superior to groove alone
• NHMRC Level III Evidence: Bone tunnel technique preferred for SPR reconstruction
• No formal Australian consensus guidelines specific to peroneal tendon surgery
• Follow AOFAS (American Orthopaedic Foot & Ankle Society) clinical practice guidelines

Australian Epidemiology

• Peroneal tendon disorders: 0.5-1% of ankle injuries presenting to ED
• Chronic lateral ankle instability: 20-30% have associated peroneal pathology
• Higher incidence in athletes: Basketball, soccer, netball common in Australian context
• Aboriginal and Torres Strait Islander populations: Limited specific data, general ankle injury rates higher