Mild-moderate hallux valgus · HVA 15-30°, IMA 10-13° · congruent 1st MTP joint · medial longitudinal approach
- Only for mild-moderate deformity: HVA 15-30°, IMA 10-13°, with a congruent 1st MTP joint. It is contraindicated if the HVA is greater than 30°, the IMA is greater than 13°, or the joint is incongruent — use a proximal osteotomy instead.
- The V-shaped 60° osteotomy with the apex at the DOME of the metatarsal head is inherently stable — apex too dorsal is unstable, too plantar damages the sesamoids.
- Maximum lateral translation is 50% of shaft width (typically 3-4mm); exceeding this risks loss of stability, AVN and nonunion. Each 1mm of translation corrects the IMA by about 2-3°.
- Single-screw fixation is adequate because of the chevron geometry — a 2.0mm headless compression screw placed perpendicular to the osteotomy is preferred (RCT evidence equals double-screw).
- AVN risk is less than 1% (versus 2-3% for proximal osteotomies) because the apex sits distal to the metatarsal neck, preserving the dual dorsal and plantar blood supply.
- Sesamoid reduction to Grade 0-1 is mandatory — persistent lateral subluxation means a lateral release is needed or the deformity is too severe for chevron alone (it predicts recurrence).
- Add an Akin osteotomy if the DASA is greater than 10° or the residual HVA is still greater than 15° after correction.
When & Why
Indications. The distal chevron is the operation for mild-moderate hallux valgus: a hallux valgus angle of 15-30° and an intermetatarsal angle of 10-13°, with a congruent 1st MTP joint (articular surfaces parallel on the weight-bearing AP radiograph). It is offered for a symptomatic bunion — pain, difficulty with shoe wear, cosmetic concern — that has failed conservative management (orthotics, wider shoes, activity modification tried for 3-6 months), in a patient with flexible/reducible deformity, good soft tissue quality and adequate skin elasticity. The whole ray must be assessed before committing. Exclude or plan for:
- First MTP degenerative change — arthritis precludes an osteotomy; consider fusion instead.
- First-ray hypermobility — a chevron does not address it; a Lapidus (TMT) fusion is the operation for hypermobility, severe deformity or revision.
- Metatarsus primus elevatus — risks transfer metatarsalgia after shortening.
- Interphalangeus (high DASA) — add an Akin if the DASA is greater than 10°. Adjunct procedures are added only when specifically indicated: an Akin osteotomy if the DASA is greater than 10° or the residual HVA is greater than 15° after the chevron; a lateral soft-tissue release if tight lateral structures prevent sesamoid reduction; medial capsular reefing is routine to address the soft-tissue laxity component. Contraindications.
Severe deformity (HVA greater than 30°, IMA greater than 13°) — use a scarf or proximal osteotomy; an incongruent MTP joint (requires proximal realignment); active infection; severe peripheral vascular disease; neuropathic arthropathy (Charcot).
Rheumatoid arthritis with MTP synovitis (high recurrence); a previous failed chevron (consider revision with a proximal osteotomy); metatarsus primus elevatus (transfer metatarsalgia risk); first-ray hypermobility (consider Lapidus); age under 16 years (open growth plates); heavy manual labour within 3 months.
Pre-operative assessment. Clinically, characterise the deformity (flexible versus fixed, sesamoid position), measure 1st MTP range (normal 60-70° dorsiflexion, 20-30° plantarflexion), look for transfer metatarsalgia (calluses under the lesser metatarsal heads), and examine sensation and vascularity. On weight-bearing AP and lateral radiographs measure the HVA (normal less than 15°), IMA (normal less than 9°), DASA (normal less than 10°), MTP joint congruity, sesamoid position (Grade 0-3), first metatarsal length and any arthritis. The full normal-versus-severe range is tabulated in Background & Evidence. Counsel the patient honestly: with appropriate selection, 85-90% good-to-excellent results; recurrence 5-15% (up to 25% if selection criteria are exceeded); recovery of 6-8 weeks protected weight bearing and 3-4 months to full activity; and complications including stiffness (10-20%), transfer metatarsalgia (5-10%) and nerve injury (5-10%). High heels are avoided for 6 months and a wider toe box may be needed permanently. Setup. Supine with the foot at the end of the table (a hip bump optional), ankle block or general anaesthesia, and a tourniquet on the ankle (250mmHg) or thigh (300mmHg if an ankle block is used). Loupe magnification helps nerve identification.
The Operation
The goal: through a medial approach to the first metatarsal, resect the medial eminence, cut a 60° chevron with the apex at the dome of the head, translate the capital fragment laterally to correct the intermetatarsal angle, fix it with a single screw, and balance the soft tissues so the sesamoids sit reduced under the head. The exposure — position and landmarks, the incision, the superficial dissection protecting the nerves, and the capsulotomy — is laid out as the first four steps below; it is the foundation on which all the bone work depends (see also the dorsomedial approach to the first MTP joint).
Operative sequence
- Supine, foot at the end of the table, hip bump optional; ankle block or general anaesthesia; tourniquet on the ankle at 250mmHg or the thigh at 300mmHg for an ankle block.
- Mark the bunion, the 1st MTP joint line and the planned incision with a sterile pen.
- Equipment ready: a microsagittal or 0.5mm sagittal saw, a 2.0mm headless compression screw set, small osteotomes and rongeurs, bunion dressing materials and C-arm fluoroscopy.
- A medial longitudinal incision, 3-4cm, from the mid-proximal phalanx to the mid-metatarsal neck, centred on the prominent eminence.
- Position it 2-3mm dorsal to the palpable MTP joint line — staying dorsal protects the medial plantar digital nerve, which runs 8-10mm plantar to the joint. A number-15 blade through skin only.
- Dorsomedial cutaneous nerve branches cross 3-5mm dorsal to the incision.
- An incision placed too plantar risks the medial plantar digital nerve.
- Over-aggressive retraction risks skin-flap necrosis.
- Deepen through subcutaneous tissue with sharp dissection to the MTP capsule.
- Identify and protect the dorsomedial cutaneous nerve branches (a superficial peroneal branch) crossing the field in about 80% of cases — retract them gently with vessel loops. Preserve major branches over 1mm; sacrifice a small branch only if unavoidable.
- Dorsomedial cutaneous nerve injury causes troublesome numbness or neuroma in 5-10% of cases.
- Excessive retraction devascularises the skin edges.
- Torn superficial veins cause haematoma.
- An inverted-L or straight longitudinal capsulotomy along the dorsomedial aspect of the 1st metatarsal and MTP joint, from the proximal metatarsal neck along the medial eminence to the proximal phalanx base.
- Raise the capsule as thick flaps and preserve them — they are essential for the later medial reefing that maintains correction. Elevate to expose the medial eminence and metatarsal neck; place Hohmann retractors dorsally and plantarly.
- Excessive capsular stripping devascularises the head.
- Inadvertent damage to the lateral capsule or the sesamoid complex.
- Dividing rather than preserving the capsule loses the tissue needed for reefing.
- Resect the medial eminence with the microsagittal saw oriented parallel to the medial border of the metatarsal shaft, removing typically 3-4mm — enough to eliminate the prominence once corrected.
- The cut should exit at the level of the normal medial shaft contour. Do not over-resect (more than 5mm destabilises the sesamoids and the medial column). Irrigate continuously to prevent thermal necrosis; smooth with a rasp.
- Over-resection (greater than 5mm) destabilises the sesamoids and causes lateral subluxation.
- A cut extending too plantar injures the medial plantar digital nerve or the sesamoid.
- Thermal necrosis if irrigation is inadequate; intra-articular violation if the saw angles dorsally.
- Mark the V-osteotomy with a pen or electrocautery. The apex sits at the DOME (geometric centre) of the metatarsal head — the critical landmark for stability.
- Mark a 60° V with equal-length arms of 8-10mm each: the first arm from dorsomedial to plantar-lateral, the second from plantar-medial to dorsolateral, both exiting at the lateral cortex.
- Apex too dorsal (proximal to the dome) is unstable and risks malunion or nonunion.
- Apex too plantar damages the sesamoids or fractures the plantar cortex.
- Arms shorter than 6mm raise fracture risk during translation; unequal arms give asymmetric stress and deformity.
- With the microsagittal saw, make the two V-cuts precisely at 60° to the shaft axis, meeting at the apex.
- Both cuts must be complete through the lateral cortex to let the head translate — incomplete cuts fracture when the head is moved. Irrigate copiously; complete the cuts with a small osteotome if needed to protect soft tissues.
- Incomplete lateral-cortex cuts fracture during translation.
- Thermal necrosis and AVN risk if irrigation is inadequate.
- Saw-blade drift gives an asymmetric, unstable V; soft-tissue injury if the saw penetrates the lateral cortex excessively.
- Mobilise the capital (head) fragment by gentle distraction and rotation, then translate it laterally, typically 3-4mm (maximum 50% of shaft width).
- Impact the V with a mallet on the medial eminence to seat the chevron and lock it. If the first metatarsal is relatively long, plantarflex the fragment 1-2mm to prevent transfer metatarsalgia. Check alignment clinically and with fluoroscopy.
- Translation greater than 50% means loss of stability, increased AVN and nonunion risk, and a painful prominent lateral edge.
- Dorsiflexion malposition causes transfer metatarsalgia to the lesser metatarsals.
- Inadequate translation undercorrects the IMA; excessive force fractures the plantar cortex.
- Fix with a single screw placed perpendicular to the osteotomy plane. Preferred: a 2.0mm headless compression screw (fully buried, no removal needed).
- Drill a guide wire perpendicular to the osteotomy, confirm with fluoroscopy, over-drill the proximal fragment (glide hole) and under-drill the distal fragment (thread hole) for a lag effect, then insert the screw. Alternative: a 2.0-2.7mm cortical screw with a washer (may need later removal). Confirm stability manually.
- Screw prominence causes pain if it is not buried.
- Inadequate compression if the screw is not perpendicular to the osteotomy.
- MTP joint penetration if too long or misangulated; loss of correction if fixation is unstable — check manually before closure.
- Assess the sesamoids by palpating the plantar foot and with intra-operative fluoroscopy. They should be reduced under the metatarsal head (Grade 0-1).
- If they remain laterally subluxated (Grade 2-3), the lateral structures are tight (a release is needed) or the deformity is too severe for a chevron alone. Persistent subluxation predicts recurrence.
- Unreduced sesamoids (Grade 2-3) carry a high recurrence risk and a poor outcome.
- This may be a procedure-selection error — decide on a lateral release or abandon and plan a proximal osteotomy.
- If the sesamoids are not reduced or the lateral structures are tight, release the adductor hallucis from the lateral base of the proximal phalanx and release the lateral MTP capsule.
- This can be done through the same medial incision (blunt dissection laterally) or through a separate 1cm lateral incision. Aim for slight overcorrection into varus, which settles to neutral.
- The lateral digital nerve and artery run about 5mm lateral to the lateral capsule — stay on the capsule, blunt dissection only.
- Over-aggressive release overcorrects into hallux varus (2-5%); an inadequate release leaves the sesamoids subluxated.
- Add a proximal-phalanx Akin (medial closing-wedge) osteotomy if the residual HVA is still greater than 15° after the chevron, or if the DASA is greater than 10° (interphalangeal deviation).
- Create a 2-3mm medial closing wedge at the base of the proximal phalanx, remove it with the microsagittal saw, close and fix with a 2.0mm screw, K-wire or memory staple.
- Excessive wedge overcorrects into interphalangeal varus; an insufficient wedge undercorrects.
- Interphalangeal stiffness; proximal-phalanx fracture in poor bone.
- Reef (imbricate) the medial capsule with a pants-over-vest technique or direct repair with 2-3mm overlap, using 2-0 absorbable sutures.
- This addresses the soft-tissue laxity and maintains the osseous correction. Avoid excessive tension (it causes stiffness) — aim for neutral to slight varus (0-5°) which settles to neutral. Test MTP range: at least 50-60° dorsiflexion.
- A too-tight capsule overcorrects into varus and is the commonest cause of post-op stiffness.
- Inadequate plication undercorrects; sutures too tight can rupture the capsule.
- Close subcutaneous tissue with 3-0 absorbable sutures and skin with 4-0 subcuticular absorbable or interrupted 4-0 nylon.
- Apply a bunion dressing: gauze between the 1st and 2nd toes holding the corrected alignment, the hallux in slight varus/neutral, fluffed gauze around the foot, and a compression wrap (not too tight). Apply a post-operative stiff-soled shoe or bunion boot.
- Wound dehiscence (5-10%, higher under tension); a too-tight dressing compromises perfusion.
- Loss of correction if the dressing is inadequate; skin necrosis at pressure points.
- Obtain AP, lateral and sesamoid-axial fluoroscopic views: confirm osteotomy position, screw placement (perpendicular, not in the joint), sesamoid reduction to Grade 0-1, and overall alignment (HVA less than 15°, IMA less than 9°).
- Irrigate thoroughly with 500ml-1L saline; achieve meticulous haemostasis with bipolar cautery (avoid monopolar near nerves) before dressing to prevent haematoma. Document the images.
- Inadequate imaging misses malposition or joint penetration.
- Haematoma from poor haemostasis increases infection and stiffness.
- Monopolar near neurovascular structures injures nerves.
The metatarsal head has a dual blood supply: dorsally from the dorsal metatarsal artery (off the dorsalis pedis) and plantarly from the plantar metatarsal arteries (off the plantar arch). Both send terminal branches that enter the bone at the neck, 3-4mm proximal to the articular cartilage. Because the chevron apex sits at the dome — distal to where these vessels enter — both vascular territories survive, and the limited translation (less than 50%) and minimal periosteal stripping preserve the remaining periosteal inflow. This is the anatomical reason the AVN rate is less than 1% with the distal chevron versus 2-3% with proximal osteotomies performed at or above the neck.
The apex goes at the dome of the metatarsal head with equal 8-10mm arms; translate the capital fragment a maximum of 50% of shaft width (typically 3-4mm) and impact the V. Each 1mm of lateral translation corrects the IMA by about 2-3°, so 3-4mm gives 6-12° of correction — exactly the range suited to a mild-moderate deformity.
After fixation, confirm on fluoroscopy that the sesamoids sit reduced to Grade 0-1. If Grade 2-3 subluxation persists, the lateral structures are tight (release them) or the deformity is too severe for a chevron alone — a residual round lateral edge and an unreduced sesamoid complex are powerful predictors of recurrence.
Aftercare & Complications
Rehabilitation. Protected weight bearing in a stiff-soled shoe is the backbone of recovery; early MTP motion prevents the commonest complication, stiffness.
- Timing
- 0-2 weeks
- Immobilisation & weight-bearing
- Bunion dressing maintaining correction; heel weight-bearing in stiff-soled shoe
- Therapy & milestones
- Elevation and ice; finger motion only; dressing changed at 48 hours
- Timing
- 2-6 weeks
- Immobilisation & weight-bearing
- Heel weight-bearing in post-op shoe; sutures out at 10-14 days
- Therapy & milestones
- Gentle MTP dorsiflexion/plantarflexion from 2 weeks; 6-week X-rays for union and alignment
- Timing
- 6-12 weeks
- Immobilisation & weight-bearing
- Transition to supportive shoes at 6-8 weeks once radiographic healing
- Therapy & milestones
- Full weight-bearing; resisted exercises and toe curls; walking encouraged
- Timing
- 3-6 months
- Immobilisation & weight-bearing
- Normal shoes; avoid heels greater than 5cm for 6 months
- Therapy & milestones
- Impact sport from 3-4 months; residual swelling settles over 3-4 months
- Recognition
- Return of the bunion, sesamoid subluxation on X-ray, symptoms returning months to years later
- Prevention
- Appropriate selection (HVA less than 30°, IMA less than 13°); intra-op sesamoid reduction; medial reefing; lateral release if needed; footwear compliance
- Management
- Mild: orthotics, wider shoes. Symptomatic or severe: revision with a proximal osteotomy (scarf, Ludloff) or Lapidus fusion
- Recognition
- Medial deviation of the hallux, difficulty with push-off, shoe-wear problems — often iatrogenic
- Prevention
- Avoid excessive lateral translation (max 50%) and an over-aggressive lateral release; appropriate capsular tension; aim neutral to 5° valgus
- Management
- Mild or flexible: observation, stretching. Severe or fixed: reverse chevron, medial soft-tissue release, interpositional arthroplasty or MTP fusion
- Recognition
- Pain under the 2nd-3rd metatarsal heads, plantar calluses, relative lengthening of the lesser metatarsals
- Prevention
- Limit shortening (the chevron shortens about 2mm); consider 1-2mm plantarflexion if the 1st metatarsal is long
- Management
- Orthotics with a metatarsal pad, shoe modification. Persistent beyond 6 months: lesser-metatarsal shortening (Weil)
- Recognition
- Persistent pain and stiffness, collapse of the head on X-ray (sclerosis, fragmentation, flattening), marrow change on MRI
- Prevention
- Minimal periosteal stripping at the neck; translation no more than 50%; apex at the dome preserves both supplies
- Management
- Early or partial: protected weight bearing, observe 6-12 months (may revascularise). Late collapse: MTP fusion or resection arthroplasty
- Recognition
- Dorsiflexion less than 50° (normal 60-70°), functional limitation, peri-articular adhesions
- Prevention
- Early ROM exercises from 2 weeks; avoid excessive capsular tension; minimise intra-articular trauma
- Management
- Aggressive physiotherapy, manual mobilisation, night dorsiflexion splint. Persistent beyond 6 months: MUA or adhesion release
- Recognition
- Numbness of the medial or dorsomedial hallux or first web space, a painful neuroma (positive Tinel), burning dysaesthesia
- Prevention
- Identify and protect the dorsomedial cutaneous branches; incision 2-3mm dorsal to the joint line; sharp dissection under direct vision
- Management
- Numbness only: reassurance. Neuroma: desensitisation, gabapentin, nerve blocks. Persistent: neuroma excision or burial
- Recognition
- Persistent pain at the osteotomy, motion at the site, loss of correction, lucency beyond 3 months, hardware loosening
- Prevention
- Complete cuts, adequate impaction, a screw perpendicular to the osteotomy, avoid smoking, optimise comorbidities, protected weight bearing for 6 weeks
- Management
- Nonunion: revision ORIF with bone graft, consider a plate or conversion to fusion. Malunion: revision osteotomy or fusion if symptomatic
Additional complications by timing.
Fracture of the metatarsal during translation (from incomplete cuts or excessive force); sesamoid fracture if the saw extends too plantar during eminence resection; intra-articular screw placement — check with fluoroscopy.
Wound dehiscence (5-10%, higher under tension or vascular compromise); infection (1-2% with prophylaxis, higher in diabetics); haematoma from inadequate haemostasis; hardware prominence if a headed screw is used.
Complex regional pain syndrome (1-2% — physiotherapy, desensitisation, medications); hardware irritation (a prominent screw may need removal); arthritis progression if pre-existing degenerative change; dissatisfaction with cosmesis despite technical success.
Viva & Exam Focus
CHEVRONCHEVRON — indication criteria
STABLE VSTABLE V — technical keys to chevron stability
Five structures at risk across the case.
Multiple branches cross the surgical field 3-5mm dorsal to the incision line. Identify them under loupe magnification during superficial dissection and retract gently with a vessel loop; sharp dissection under direct vision.
Runs 8-10mm plantar to the MTP joint line and is vulnerable during eminence resection. Keep the incision 2-3mm dorsal to the joint, limit the saw depth during eminence removal, and never extend a cut more than 5mm plantar to the articular surface.
Lies 5-6mm plantar to the metatarsal-head articular surface, attached to flexor hallucis brevis. Direct the osteotomy cuts dorsally, limit plantar eminence resection to 3-4mm, and check sesamoid integrity after the eminence is removed.
Runs 5mm lateral to the lateral MTP capsule and is at risk during a lateral release. Stay on the capsule, use blunt dissection only, and release the adductor from the lateral base of the proximal phalanx under direct vision.
Dorsal and plantar terminal branches enter at the neck, 3-4mm proximal to the articular cartilage. Minimise periosteal stripping at the neck, limit translation to 50%, and keep the apex at the dome to preserve both vascular territories.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“Why is the chevron osteotomy inherently stable, and what biomechanical principles allow single-screw fixation?”
“What is the maximum lateral translation for a chevron osteotomy, and what are the biomechanical and biological consequences of exceeding it?”
“Why is the AVN risk lower with a distal chevron than with proximal metatarsal osteotomies, and what anatomy is responsible?”
Indications
- Mild-moderate hallux valgus: HVA 15-30°, IMA 10-13° (exceeding these is the wrong procedure)
- Congruent 1st MTP joint (parallel articular surfaces on AP X-ray)
- Symptomatic bunion failing conservative care (orthotics, wider shoes, 3-6 months)
- Flexible or reducible deformity, good soft tissue quality
Key anatomy
- Dorsomedial cutaneous nerve crosses the field 3-5mm dorsal to the incision (injury 5-10%)
- Medial plantar digital nerve runs 8-10mm plantar to the joint
- Dual blood supply from dorsal and plantar arteries entering at the neck, preserved by the chevron
- Sesamoids: medial (tibial) and lateral (fibular) in FHB tendons — reduce to Grade 0-1
- First metatarsal: head width 16-18mm, neck 10-12mm, typical shaft width 8mm
Critical steps
- Medial longitudinal incision 3-4cm, 2-3mm dorsal to the joint line
- Identify and protect the dorsomedial cutaneous nerve branches with vessel loops
- Inverted-L capsulotomy preserving thick flaps for reefing
- Resect the medial eminence 3-4mm in line with the shaft (over-resection greater than 5mm destabilises sesamoids)
- Mark a 60° V with the apex at the dome, equal arms 8-10mm
- Complete the cuts through the lateral cortex with copious irrigation
- Translate the capital fragment laterally 3-4mm (max 50%) and impact
- Single 2.0mm headless screw perpendicular to the osteotomy
- Confirm sesamoid reduction to Grade 0-1 (else lateral release)
- Reef the medial capsule pants-over-vest without excessive tension
Danger zones
- Dorsomedial cutaneous nerve (3-5mm dorsal): identify and protect
- Medial plantar digital nerve (8-10mm plantar): stay 2-3mm dorsal to the joint
- Medial sesamoid (5-6mm plantar to the surface): direct cuts dorsally
- Lateral neurovascular bundle (5mm lateral to the capsule): stay on the capsule
- Head vessels (enter at the neck 3-4mm proximal): apex at the dome preserves both
Technique pearls
- CHEVRON: Congruent MTP, HVA 15-30°, Elastic skin, V-shape IMA 10-13°, Reducible, Osteotomy for mild-moderate, Normal DASA less than 10°
- STABLE V: Sixty degrees, Translation max 50%, Apex at dome, Both arms equal, Lateral cortex complete, Exit lateral, V impaction
- Single screw adequate (RCT equals double-screw)
- Max 50% translation: beyond it = instability, AVN risk, prominent lateral edge
- Sesamoid reduction mandatory: Grade 2-3 persistence means lateral release or wrong procedure
- Plantarflex 1-2mm if the 1st metatarsal is long (prevents transfer metatarsalgia)
- Add Akin if DASA greater than 10° or residual HVA greater than 15°
Complications
- Recurrence 5-15% (up to 25% if HVA greater than 25°): selection and sesamoid reduction
- Hallux varus 2-5% (overcorrection): avoid excessive translation or release
- Transfer metatarsalgia 5-10%: the chevron shortens about 2mm
- AVN less than 1%: minimal stripping, translation max 50%, apex at the dome
- Stiffness 10-20%: ROM from 2 weeks, avoid over-reefing
- Nerve injury 5-10%: protect the dorsomedial cutaneous nerve
- Nonunion 1-3%: complete cuts, impaction, screw perpendicular, no smoking
Post-op protocol
- Bunion dressing 2 weeks (gauze between toes, compression wrap)
- Heel weight-bearing in a stiff-soled shoe for 6 weeks
- ROM exercises from 2 weeks (gentle DF/PF, 10 reps 3-4x daily)
- Sutures out 10-14 days; 6-week X-rays (HVA less than 15°, IMA less than 9°)
- Supportive shoes at 6-8 weeks; impact sport at 3-4 months
- Avoid heels greater than 5cm for 6 months; swelling settles over 3-4 months
Exam tips
- State the indications precisely: HVA 15-30°, IMA 10-13°, congruent MTP
- Emphasise the apex at the dome: too dorsal = unstable, too plantar = sesamoid damage
- Know the 50% translation rule and its consequences
- Explain stability: large contact area, interdigitation, equal arms
- Explain low AVN (less than 1%): dual supply preserved, apex distal to the neck
- Distinguish from scarf: scarf for moderate-severe (IMA 13-20°), more dissection
- Severe deformity (HVA greater than 30°, IMA greater than 15°): chevron contraindicated — proximal or Lapidus
Background & Evidence
Hallux valgus is classified by deformity magnitude, and the chevron's place in the algorithm is defined by where a given deformity sits. The distal chevron is the operation for the mild-moderate range; severe or incongruent deformity, arthritis or hypermobility escalate to shaft, proximal or fusion procedures.
- Normal
- Less than 15°
- Chevron range
- 15-30°
- Severe (not chevron)
- Greater than 30°
- Normal
- Less than 9°
- Chevron range
- 10-13°
- Severe (not chevron)
- Greater than 13°
- Normal
- Less than 10°
- Chevron range
- Add Akin if greater than 10°
- Severe (not chevron)
- —
- Normal
- Congruent
- Chevron range
- Congruent (required)
- Severe (not chevron)
- Incongruent
- Normal
- 0-1
- Chevron range
- Aim for 0-1 post-op
- Severe (not chevron)
- Grade 3 (high recurrence)
- Normal
- Conservative
- Chevron range
- Chevron ± Akin
- Severe (not chevron)
- Proximal osteotomy or Lapidus
Surgical anatomy. The first metatarsal averages 64mm in length, with a head width of 16-18mm and the neck (the narrowest point) 10-12mm; the head is a spherical dome whose cartilage extends onto the dorsal and plantar surfaces. The medial (tibial) and lateral (fibular) sesamoids sit in the two heads of flexor hallucis brevis, separated by the crista on the plantar head. The nerves at risk are the dorsomedial cutaneous nerve (a superficial peroneal branch crossing the dorsomedial foot, injured in 5-10%), the medial plantar digital nerve (a branch of the medial plantar nerve, 8-10mm plantar to the joint) and the lateral digital nerve (running with the first web-space artery, 5mm lateral to the lateral capsule). The head's dual blood supply (dorsal metatarsal artery off the dorsalis pedis; plantar metatarsal arteries off the plantar arch) enters at the neck — the key to the chevron's low AVN rate. The soft tissues include the medial capsule (thickened medially, attenuated in hallux valgus and requiring reefing), the lateral capsule and adductor hallucis (contracted and causing lateral deviation), the abductor hallucis (weakened in the bunion), flexor hallucis brevis and extensor hallucis longus (which bowstrings laterally in the deformity). Why the V is stable. The chevron geometry is inherently stable for five reasons: a large bone-contact area versus a straight cut; interdigitation (the dovetail resists shear when impacted); equal-length arms (8-10mm) that balance compressive forces; the apex at the dome that neutralises bending moments; and compression generated by translation perpendicular to the osteotomy plane. Translation biomechanics: each 1mm of lateral translation corrects the IMA by about 2-3°, the maximum is 50% of shaft width (3-4mm), and 1-2mm of plantarflexion can be added if the first ray is relatively long. Fixation: a single screw placed perpendicular to the osteotomy is adequate (RCT evidence equals double-screw); a 2.0mm headless compression screw is preferred (buried, no removal), with a headed screw and washer or a K-wire as alternatives. Chevron versus the alternatives.
- Deformity range
- IMA 10-13°, HVA 15-30°
- AVN risk
- Less than 1%
- Recovery
- Weight-bearing in a post-op shoe, about 6 weeks
- Notes
- Default for mild-moderate; fast (about 45 min)
- Deformity range
- IMA 13-20°
- AVN risk
- Low
- Recovery
- Similar
- Notes
- Longer learning curve, more dissection, allows more translation
- Deformity range
- IMA greater than 13°, severe
- AVN risk
- 2-3%
- Recovery
- Non-weight-bearing 6-8 weeks
- Notes
- For severe deformity
- Deformity range
- Hypermobility, severe, revision
- AVN risk
- —
- Recovery
- Longest; nonunion 5-10%
- Notes
- Addresses first-ray hypermobility
Outcomes. With appropriate selection, the chevron gives 85-90% good-to-excellent results and 80-85% satisfaction at two or more years; recurrence is 5-15% overall (up to 25% if the selection criteria are exceeded), and about 90% return to their pre-operative activity by 4-6 months. At five years, HVA typically improves from 25-30° to 10-15° and IMA from 12-14° to 7-9°, with 85-90% maintaining correction and 80-85% pain-free or minimally symptomatic. By ten or more years, recurrence rises to 15-20% (especially if the initial HVA was greater than 25°), 10-15% develop MTP arthritis (similar to natural history), and 5-10% require revision — usually for recurrence. Positive predictors are HVA less than 25° with IMA less than 13°, a congruent joint, sesamoid Grade 0-2 pre-op, footwear compliance and age over 30. Negative predictors are HVA greater than 30° or IMA greater than 15° (a selection error), rheumatoid or inflammatory arthropathy, first-ray hypermobility, early return to high heels, and obesity (BMI greater than 35 associated with recurrence). Technical modifications supported by evidence: single-screw fixation equals double-screw (RCTs); headless screws lower prominence with no outcome difference; a concurrent Akin improves HVA correction by 5-8° when indicated (DASA greater than 10° or residual HVA greater than 15°) but adds stiffness risk if used routinely without indication.
References
A new osteotomy for hallux valgus: a horizontally directed V displacement osteotomy of the metatarsal head
- Original description of the horizontally directed V (chevron) displacement osteotomy of the first metatarsal head for hallux valgus and metatarsus primus varus.
- Corrects primus varus, valgus tilt of the distal articular surface and axial rotation of the great toe, combined with soft-tissue balancing.
- The inherent geometric stability allowed early ambulation (around the third post-operative day), often without internal fixation in the original series.
Five-Year Follow-up of Minimally Invasive Distal Metatarsal Chevron Osteotomy in Comparison with the Open Technique: A Randomized Controlled Trial
- Randomised controlled trial; 39 of 47 feet analysed at 5 years comparing minimally invasive versus open distal chevron osteotomy.
- No significant difference between groups in AOFAS forefoot score, VAS pain, satisfaction, radiographic correction, joint degeneration or range of motion at 5 years.
- Durable correction and outcome maintained to 5 years with both open and percutaneous distal chevron.
Comparison of outcomes of different osteotomy sites for hallux valgus: a systematic review and meta-analysis
- Systematic review and meta-analysis of RCTs and CCTs (10 studies, 793 feet) comparing distal, mid-shaft and proximal first-metatarsal osteotomy sites.
- For mild-to-moderate deformity, no significant clinical or radiological difference between distal (chevron) and mid-shaft (scarf) osteotomies in HVA, IMA, AOFAS or VAS.
- Distal-versus-proximal comparisons were conflicting; data for severe deformity remain insufficient.
The shape of the lateral edge of the first metatarsal head as a risk factor for recurrence of hallux valgus
- Case-control radiographic study (60 normal versus 60 hallux valgus feet) defining the round, angular and intermediate lateral-edge shapes of the metatarsal head.
- A persistent positive round sign at early post-operative follow-up was strongly associated with recurrence (odds ratio 12.7, 95% CI 3.2 to 50.4).
- Incomplete reduction of the lateral head shape and the sesamoid complex predicts later loss of correction.
Treatment of hallux valgus deformity
- EFORT instructional review of hallux valgus assessment and the full surgical algorithm (distal and shaft osteotomies, Akin, proximal osteotomy, Lapidus, MTP fusion).
- Procedure selection is dictated by deformity magnitude, first MTP degenerative change and first tarsometatarsal stability rather than a single default operation.
- Weight-bearing AP and lateral radiographs are essential for planning; non-operative treatment controls symptoms but does not correct the deformity.