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 more common in women Risk factors intrinsic genetic predisposition 70% of pts with hallux valgus have family history increased distal metaphyseal articular angle (DMAA) ligamentous laxity (1st tarso-metatarsal 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 sesamoido-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 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%), also overcorrection and hallux varus Anatomy Pathoanatomy cascade Presentation Symptoms presents with difficulty with shoe wear due to medial eminence pain over prominence at MTP joint 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 mobility callous formation sesamoid pain/arthritis evaluate associated deformities pes planus lesser toe deformities midfoot and hindfoot conditions Imaging Radiographs views standard series should include weight bearing AP, Lat, and oblique 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 Hallux valgus (HVA) Long axis of 1st MT and prox. phalanx Identifies MTP deformity Normal < 15° Intermetatarsal angle (IMA) Between long axis of 1st and 2nd MT Normal < 9 ° Distal metatarsal articular (DMAA) Between 1st MT axis and line through base of distal articular cap Identifies MTP joint incongruity Normal < 10° Hallux valgus interphalangeus (HVI) Between long. axis of distal phalanx and proximal phalanx Normal < 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) 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 present despite shoe modification do not perform for cosmetic reasons alone technique soft tissue procedure indicated in very mild disease in young female (almost never) distal osteotomy indicated in mild disease (IMA < 13) proximal or combined osteotomy indicated in more moderate disease (IMA > 13) 1st TMT arthrodesis arthritis at TMT joint or instability fusion procedures indicated in severe deformity/spasticity/arthritis MTP resection arthroplasty only indicated 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 similar to adults if physis is closed (except in severe deformity) Techniques Soft Tissue Procedures modified McBride indications goal is to correct an incongruent MTP joint (phalanx not lined up with articular cartilage of MT head). Usually done in patients with a HVA less than 25 degrees IMA deformity less than 15 degrees usually in patient 30-50 years of age 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 indications mild disease (HVA 15-25°, IMA < 13°) unable to correct pronation deformity distal metatarsal osteotomies include Chevron biplanar Chevron (corrects DMAA) Mitchell may be combined with proximal phalanx osteotomy (Akin-medial closing wedge osteotomy) proximal metatarsal osteotomy indications moderate disease (HVA >40°, IMA >13°) proximal metatarsal osteotomies include crescentic osteotomy Broomstick osteotomy Ludloff Scarf double (proximal and distal) osteotomy indications severe disease (HVA 41-50°, IMA 16-20°) first cuneiform osteotomy indications severe deformity in young patient with open physis Proximal phalanx osteotomies 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) 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 Fusion procedures Lapidus procedure (1st metatarsocuneiform arthrodesis with modified McBride) indications severe deformity (very large IMA) arthritis at 1st TMT metatarsus primus varus hypermobile 1st TMT joint concomitant pes planus Lapidus procedure, in isolation, can fail to correct pronation of the first ray MTP Arthrodesis indications are hallux valgus in cerebral palsy Down's syndrome Rheumatoid arthritis Gout Severe DJD Resection arthroplasty proximal phalanx (Keller) resection arthroplasty indications largely abandoned rarely indicated in some elderly patient with reduced function demands 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, Ehler-Danlos MTP arthrodesis Surgical Indications for Various Techniques to treat Hallux Valgus HVA IMA Modifier Procedure Mild < 25° < 13° Distal MT osteotomy215737 Chevron osteotomy Biplanar if DMAA > 10° with mod McBride Moderate 26-40° 13-15° Proximal MT +/- distal MT osteotomy Chevron/mod McBride + Akin Proximal MT osteotomy and mod McBride Severe 41-50° 16-20° Double osteotomy, DMAA > 15° Proximal MT osteotomy plus biplanar chevron, mod McBride Lapidus procedure plus Akin 41-50° 16-20° Elderly/very low demand patient Keller resection arthroplasty 41-50° 16-20° 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 15-25° IMA < 13° 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. IMA 14-18° DMAA is normal or increased Dorsal malunion with transfer metatarsalgia Recurrence Proximal Crescentic or Broomstick Proximal metatarsal osteotomy plus modified McBride Severe deformity IMA > 20° HVA > 50° 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 Indicated in moderate to severe hallux valgus DJD of 1st MTP 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 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 that 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 Avascular necrosis medial capsulotomy is primary insult to blood flow to metatarsal head distal metatarsal oseotomy and lateral soft tissue release inconjunction 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 crescentric osteotomies Hallux Varus caused by overcorrection of 1st IMA excessive lateral capsular release with overtightening of medial capsule overresection of medial first metatarsal head lateral sesamoidectomy 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 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 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.