summary Hallux Valgus, commonly referred to as a bunion, is a complex valgus deformity of the first ray that can cause medial big toe pain and difficulty with shoe wear. Diagnosis is made clinically with presence of a hallux that rests in a valgus and pronated position. Radiographs of the foot are obtained to identify the severity of the disease and for surgical planning. Treatment can be nonoperative with shoe modifications for mild and minimally symptomatic cases. Surgical management is indicated for progressive deformity and difficulty with shoe wear. Epidemiology Demographics occurs in ~23% of patients 18 to 65 years old more common in women (up to 15:1) up to 30% of females Risk factors intrinsic genetic predisposition 70% of patients with hallux valgus have family history increased distal metaphyseal articular angle (DMAA) ligamentous laxity (1st tarsometatarsal joint instability) convex metatarsal head 2nd toe deformity/amputation pes planus rheumatoid arthritis cerebral palsy extrinsic shoes with high heel and narrow toe box Etiology Two forms exist adult hallux valgus adolescent & juvenile hallux valgus Pathoanatamy valgus deviation of phalanx promotes varus position of metatarsal the metatarsal head displaces medially, leaving the sesamoid complex laterally translated relative to the metatarsal head sesamoids remain within the respective head of the flexor hallucis brevis tendon and are attached to the base of the proximal phalanx via the sesamoid-phalangeal ligament this lateral displacement can lead to transfer metatarsalgia due to shift in weight-bearing medial MTP joint capsule becomes stretched and attenuated while the lateral capsule becomes contracted adductor tendon becomes deforming force inserts on fibular sesamoid and lateral aspect of proximal phalanx lateral deviation of EHL further contributes to deformity plantar and lateral migration of the abductor hallucis causes muscle to plantar flex and pronate phalanx windlass mechanism becomes less effective leads to transfer metatarsalgia Associated conditions hammer toe deformity callosities pes planus associated with deformity progression Marfan syndrome Ehlers-Danlos syndrome Juvenile and Adolescent Hallux valgus factors that differentiate juvenile/adolescent hallux valgus from adults often bilateral and familial pain usually not primary complaint varus of first MT with widened IMA usually present DMAA usually increased often associated with flexible flatfoot complications recurrence is most common complication (>50%) overcorrection hallux varus Differential diagnosis gout hallux rigidus rheumatoid arthritis turf toe hallux valgus interphalangeus Anatomy Pathoanatomy cascade Osteology valgus deviation of great toe and varus deviation of first metatarsal sesamoids displace lateral to metatarsal head loss of the windless mechanism results in transfer metatarsalgia Musculature muscles forming the plantar plate abductor hallucis flexor hallucis brevis flexor hallucis longus (becomes deforming force) adductor hallucis (becomes deforming force) Presentation History slowly progressing deformity pain with ambulation Symptoms presents with difficulty with shoe wear due to medial eminence pain over prominence at MTP joint transfer metatarsalgia compression of digital nerve may cause symptoms Physical exam Hallux rests in valgus and pronated due to deforming forces illustrated above examine entire first ray for 1st MTP ROM 1st tarsometatarsal hypermobility MTP crepitus and grind test callous formation sesamoid pain/arthritis evaluate associated deformities pes planus lesser toe deformities midfoot and hindfoot conditions Imaging Radiographs recommended views standard series should include weight bearing AP, Lat, and oblique views optional views sesamoid view can be useful findings lateral displacement of sesamoids joint congruency and degenerative changes can be evaluated radiographic parameters (see below) guide treatment Radiographic Measurements in Hallux Valgus Measurement Importance Normal Hallux valgus (HVA) Long axis of 1st MT and prox. phalanx Identifies MTP deformity < 15° Intermetatarsal angle (IMA) Between long axis of 1st and 2nd MT < 9 ° Distal metatarsal articular (DMAA) Between 1st MT axis and line through base of distal articular cap Identifies MTP joint incongruity < 15° Hallux valgus interphalangeus (HVI) Between long. axis of distal phalanx and proximal phalanx Predisposing factor for hallux valgus < 10° Metatarsus adductus angle Angle between the second metatarsus and the longitudinal axis of the lesser tarsus (using the 4th or 5th metatarso-cuboid joint as a reference) Predisposing factor for hallux valgus < 10° Treatment - Adult Hallux Valgus Nonoperative shoe modification/ pads/spacers/orthoses indications first line treatment orthoses more helpful in patients with pes planus or metatarsalgia Operative surgical correction indications when symptoms persist despite shoe modifications do not perform for cosmetic reasons alone technique soft tissue procedure (modified McBride) indications only for mild disease (IMA < 11 degrees, HVA < 35 degrees) typically performed in combination with an osteotomy (almost never alone) usually in patients 30-50 years of age outcomes no studies have assessed deformity correction of modified McBride alone akin osteotomy indications hallux valgus interphalangeus congruent joint with DMAA <10° as a secondary procedure if a primary procedure (e.g., chevron or distal soft-tissue procedure) that did not provide sufficient correction due to a large DMAA or HVI some authors perform Akin together with/at the time of proximal osteotomy+distal soft tissue correction because this results in progressive increase in HVI outcomes improves pain, radiographic outcomes, and PROMs distal osteotomy indications mild disease (HVA < 30°, IMA < 13°) unable to correct pronation deformity outcomes chevron osteotomy outperformed nonoperative treatment in an RCT proximal or combined osteotomy indications proximal osteotomy: moderate disease (HVA >25°, IMA >13°) double osteotomy: severe disease (HVA 41-50°, IMA 16-20°) outcomes after scarf osteotomy, decrease in VAS pain of 5.8 to 1.1 and improvement in IMA from 13 degrees to 5.6 degrees 1st TMT arthrodesis (Lapidus) indications severe deformity (HVA > 40 degrees, IMA > 20 degrees) arthritis at TMT joint or ligamentous laxity outcomes patient satisfaction of 81% with improvement in HVA and IMA at 24 months no difference in radiographic outcomes of lapidus versus distal osteotomy in a RCT 1st MTP arthrodesis indications severe deformity (HVA > 40 degrees, IMA > 20 degrees) cerebral palsy down syndrome rheumatoid arthritis gout MTP arthritis outcomes ~90% patient satisfaction MTP resection arthroplasty indications largely abandoned only in elderly patients with low functional demands Treatment - Juvenile and Adolescent Hallux valgus Nonoperative shoe modification indications pursue nonoperative management until physis closes Operative surgical correction indications best to wait until skeletal maturity to operate can not perform proximal metatarsal osteotomies if physis is open (cuneiform osteotomy OK) surgery indicated in symptomatic patients with an IMA > 10° and HVA of > 20° consider double MT osteotomy in adolescent patients with increased DMAA technique soft tissue procedure alone not successful first cuneiform osteotomy used for severe disease with open physis similar to adults if physis is closed (except in severe deformity) Techniques Soft Tissue Procedures modified McBride goal is to correct an incongruent MTP joint (phalanx not lined up with articular cartilage of MT head) rarely appropriate in isolation usually performed in conjunction with medial eminence resection MT osteotomy 1st TMT arthrodesis (Lapidus procedure) technique includes release of adductor from lateral sesamoid/proximal phalanx lateral capsulotomy medial capsular imbrication (original McBride included lateral sesamoidectomy) Metatarsal Osteotomies distal metatarsal osteotomy distal metatarsal osteotomies include Chevron medial approach L-shaped capsulectomy osteotomy cut at 55-60 degrees fixation options include single screw or absorbable pin biplanar Chevron (corrects DMAA) same Chevron osteotomy with addition of bone removal from dorsomedial and plantar medial limbs oblique medial wedge removed Mitchell distal 1st MT osteotomy (extra-articular). may be combined with proximal phalanx osteotomy (Akin-medial closing wedge osteotomy) proximal metatarsal osteotomy proximal metatarsal osteotomies include crescentic osteotomy osteotomy made with crescentic saw blade distal fragment rotated laterally Scarf medial approach to the metatarsal shaft metatarsal shaft Z osteotomy longitudinal plantar sloping cut proximal and distal chevron osteotomies can correct deformity and adjust length fixation with 2 screws Broomstick osteotomy Ludloff double (proximal and distal) osteotomy combines a distal and proximal metatarsal osteotomy first cuneiform lateral opening osteotomy dorsoplantar periosteal incision osteotomy parallel to TMT joint through 75% of the cuneiform avoid completing the osteotomy laterally due to risk of over lengthening osteotomy filled with bone graft fixation with plate Proximal phalanx osteotomies Akin osteotomy medial approach to the mid shaft of the proximal phalanx medial closing wedge osteotomy avoid breaching lateral cortex fixation either with staple or screw Fusion procedures Lapidus procedure (1st metatarsocuneiform arthrodesis with modified McBride) Lapidus procedure, in isolation, can fail to correct pronation of the first ray performed with either 2 separate incisions or extended medial approach medial approach to the metatarsal head dorsal approach to the TMT joint deformity corrected with adduction, supination, and neutral plantar flexion fixation with either screws +/- plate MTP Arthrodesis medial or dorsal approach can be used avoid the EHL and dorsomedial cutaneous nerve conical reamers used for joint preparation position of toe in valgus: 5-10 degrees neutral rotation dorsiflexion: 5-10 degrees may use flat platform to simulate weight bearing fixation with screws or plate Resection arthroplasty proximal phalanx (Keller) resection arthroplasty remove base of the proximal phalanx can add interposition with allograft Surgical Indications for Specific Conditions Juvenile/Adolescent with open physis First cuneiform osteotomy Hypermobile 1st MT Lapidus procedure DJD MTP arthrodesis Skin breakdown Simple bunionectomy with medial eminence removal Gout MTP arthrodesis Recurrence with pain in 1st TMT joint Lapidus procedure Rheumatoid arthritis MTP arthrodesis Down's syndrome, CP, Ehlers-Danlos MTP arthrodesis Surgical Indications for Various Techniques to Treat Hallux Valgus HVA IMA Modifier Procedure Mild < 30° < 13° Distal MT osteotomy215737 Chevron osteotomy Biplanar if DMAA > 10° with mod McBride Moderate 30-40° 13-20° Proximal MT +/- distal MT osteotomy Chevron/mod McBride + Akin Proximal MT osteotomy and mod McBride Severe > 40° > 20° Double osteotomy, DMAA > 15° Proximal MT osteotomy plus biplanar chevron, mod McBride Lapidus procedure plus Akin > 40° > 20° Elderly/very low demand patient Keller resection arthroplasty > 40° > 20° Juvenile/Adolescent with DMAA > 20 Double osteotomy of first ray Various Hallux valgus procedures Procedure Technique Indications Complications Modified McBride Includes release of adductor from lateral sesamoid/proximal phalanx, lateral capsulotomy, medial capsular imbrication HVA < 35° IMA < 11° HVI < 15° Recurrence Hallux varus Original McBride Includes lateral sesamoidectomy and has been abandoned Not indicated Hallux Varus Chevron Distal 1st MT osteotomy (intra-articular). Can perform in two planes (Biplanar distal Chevron) Reserved for mild to moderate deformities in adults and children Biplanar chevron--> corrects increased DMAA AVN of MT head Recurrence Dorsal malunion with transfer metatarsalgia Mitchell Distal 1st MT osteotomy (extra-articular). More proximal than Chevron Same as Chevron (rarely utilized) Recurrence Malunion Transfer metatarsalgia Akin Proximal phalanx medial closing wedge osteotomy Combined with Chevron in moderate to severe deformities Hallux valgus interphalangeus Scarf / Ludloff / Mau Metatarsal shaft osteotomies. HVA > 25°, IMA > 13° DMAA is normal or increased Dorsal malunion with transfer metatarsalgia Recurrence Proximal Crescentic or Broomstick Proximal metatarsal osteotomy plus modified McBride Severe deformity IMA > 13° HVA > 25° Hallux varus Dorsal malunion with transfer metatarsalgia Recurrence Keller resection arthroplasty Includes medial eminence removal and resection of base of proximal phalanx Largely abandoned due to complications Indicated only in older patients with reduced functional demands Cock-up toe deformity Poor potential for correction of deformity MTP arthrodesis HVA > 40 degrees, IMA > 20 degrees DJD of 1st MTP Neuromuscular conditions Painful callosities beneath lesser MT heads Lapidus procedure First TMT joint arthrodesis with distal soft tissue procedures (medial eminence removal, first web space release of AdH, lateral capsule release) Moderate or severe deformity Hypermobility of first ray Nonunion (may or may not be symptomatic) Dorsiflexion of the first metatarsal with transfer metatarsalgia First Cuneiform Osteotomy Opening wedge osteotomy (often requires autograft) Children with ligamentous laxity, flatfoot, and hypermobile first ray Adolescent with an open physis Nonunion (may or may not be symptomatic) Complications Recurrence 10-47% risk depending on the procedure performed most common cause of failure is insufficient preoperative assessment and failure to follow indications e.g., failure to recognize DMAA > 10° inadequate correction of IMA e.g., failure to do adequate distal soft tissue realignment more common in juvenile/adolescent population noncompliant patient who bears weight rounded shape to the first metatarsal head residual tibial sesamoid lateral displacement increased preoperative IMA and HVA failure to perform a lateral release of the adductor hallucis tendon associated with incomplete reduction of the sesamoids pain does not correlate with deformity recurrence treat with revision surgery if patient is symptomatic Avascular necrosis rare with modern techniques medial capsulotomy is primary insult to blood flow to metatarsal head distal metatarsal osteotomy and lateral soft tissue release in conjunction do not increase risk for AVN (Chevron plus lateral release thought to increase risk in the past) treat with MTP arthrodesis with or without structural graft Dorsal malunion with transfer metatarsalgia due to overload of lesser metatarsal heads risk associated with shortening of hallux MT Lapidus proximal crescentic osteotomies treated with revision arthrodesis with bone grafting Hallux Varus 6% overall risk after surgery caused by overcorrection of 1st IMA excessive lateral capsular release with overtightening of medial capsule over resection of medial first metatarsal head lateral sesamoidectomy surgical options for symptomatic patients include reveres Scarf, reverse Chevron, reverse Akin MTP arthrodesis Cock up toe deformity due to injury of FHL most severe complication with Keller resection due to injury of FHL most severe complication with Keller resection 2nd MT transfer metatarsalgia occurs in up to 50% of hallux valgus patients often seen concomitant with hallux valgus can occur secondary to malpositioning of MTP fusion shortening metatarsal osteotomy (Weil) indicated with extensor tendon and capsular release Neuropraxia overall risk of nerve injury ~3% Painful incisional neuromas after bunion surgery frequently involve the medial dorsal cutaneous nerve (a terminal branch of the superficial peroneal nerve). It is most commonly injured during the medial approach for capsular imbrication or metatarsal osteotomy. neuropraxia typically improves over several months Nonunion occurs in ~10% of lapidus and MTP arthrodesis patients only ~33% are symptomatic treated with revision arthrodesis with bone grafting Prognosis may take 6-12 weeks to return to work improvement may take 1year dissatisfaction 10-50% risk after surgical intervention not related to surgical outcome may be related to unmet expectations