Hallux Valgus

Introduction

Not a single deformity, but rather a complex deformity of the first ray often accompanied by deformities and symptoms in lesser toe two forms exist adult hallux valgus  adolescent & juvenile hallux valgus  Epidemiology of adult hallux valgus  more common in women  70% of pts with hallux valgus have family history genetic predisposition with anatomic anomalies risk factors intrinsic genetic predisposition 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 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 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

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. phal. Identifies MTP deformity Normal < 15° Intermetatarsal angle (IMA) Between long axis of 1st and 2nd MT < 9° Distal metatarsal articular (DMAA) Between 1st MT long. axis and line through base  of distal articular cap Identifies MTP joint incongruity < 10° Hallux valgus interphalangeus (HVI) Between long. axis of distal phalanx and proximal phalanx < 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 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° severe deformity with a DMAA > 20 consider a double MT osteotomy to correct orientation of MT head articular cartilage 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 ≤ 40, IMA < 13)  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 MTP Arthrodesis indications are hallux valgus in cerebral palsy Down's syndrome Rheumatoid arthritis Gout Severe DJD Ehler-Danlos Resection arthroplasty proximal phalanx (Keller) resection arthroplasty indications largely abandoned rarely indicated in some elderly patient with reduced function demands

Surgical Indications for Various Techniques to treat Hallux Valgus HVA IMA Modifier Procedure Mild < 25° <13° Distal osteotomy Chevron osteotomy. Biplanar if DMAA > 10° usually with mod McBride Moderate 26-40° 13-15° Proximal osteotomy +/- distal osteotomy Chevron/mod McBride + Akin osteotomy 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 Elderly/very low demand patient Keller Juvenile/Adolescent with DMAA > 20 Double osteotomy of first ray 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 eminance 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

Procedure Technique Indications Complications Modified McBride Includes release of adductor from lateral sesamoid/proximal phalanx, lateral capsulotomy, medial capsular imbrication 30-50 y/o female withHVA 15-25 IMA <13 IPA < 15 -Recurrence -Hallux varus Original McBride included lateral sesamoidectomy and has been abandoned -never 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-->correct 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. reserved for mild to moderate deformities, 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 crescentric or Broomstick Proximal metatarsal osteotomies. (plus modified McBride) Severe deformity IMA > 20 HVA > 50  -hallux varus -dorsal malunion with transfer metatarsalgia-recurrence Keller resection arthroplasty Include 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 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) 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 2nd MT transfer metatarsalgia often seen concomitant with hallux valgus shortening metatarsal osteotomy (Weil) indicated with extensor tendon and capsular release  Neuropraxia Painful incisional neuromas after bunion surgery frequently involve the medial branch of the 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.