HAV part 1

HAV Lectures Overview

• The lecture series about Hallux Abducto Valgus (HAV) is divided into three parts
• Part I covers etiology, clinical/imaging evaluation, and procedures like soft tissue and proximal phalanx work.
• Part II focuses on procedures related to the distal metatarsal, metatarsal shaft, and proximal metatarsal.
• Part III discusses Lapidus procedures and emerging techniques.

Overall Objectives

• Understanding the anatomy relevant to HAV
• Performing thorough clinical evaluations
• Conducting radiographic evaluations
• Selecting appropriate procedures based on the evaluation
• Familiarizing oneself with fixation options
• Understanding potential complications

Planes of Deformity

• HAV can involve deformities in multiple planes
• Transverse plane: abduction/adduction
• Frontal plane: valgus/varus
• Sagittal plane

Terminology

• Hallux Abductus refers to the abduction of the big toe
• HAV (Hallux Abducto Valgus)
• Hallux Valgus is the lateral deviation of the great toe at the MTP joint.
• Hallux Varus is the medial deviation of the great toe at the MTP joint.

HAV Etiology: Extrinsic Factors

• Extrinsic factors include footwear, trauma, and iatrogenic causes
• Studies on footwear vary
• Tight shoes may increase the incidence of deformity
• Constricting footwear may not influence the progression of deformity
• Footwear is seen as an aggravating factor, not a causative factor

HAV Etiology: Intrinsic Factors

• Intrinsic factors have a familial component
• This includes autosomal dominant patterns
• 60-80% of individuals with HAV have a positive family history
• Those with a family history tend to have an earlier onset of HAV
• There is an ethnicity component
• African Americans have shown a higher incidence compared to Caucasians (5:1 ratio)
• Inflammatory, rheumatologic, and neuromuscular disorders contribute

HAV Etiology: Causative Factors & Predisposing Anatomy

• Hallux valgus is often combined with pes planus
• Pes planus is a predisposing factor in hallux valgus
• Mechanical malfunction of the first MTPJ is considered a causative factor for HAV deformity
• Any factor that increases STJ pronation and instability of the 1st ray can enhance HAV
• Causative factors are multifactorial
• Predisposing Anatomy includes, heredity, congenital deformity, metatarsus adductus, pes planovalgus, metatarsus primus adductus, ankle equinus, muscle imbalance, and obesity
• In 1925, Truslow found that oblique position of the 1st metatarsal can cause HAV
• In 1934, Lapidus found instability causes HAV
• In 1952, Hardy & Clapham found long 1st metatarsal causes HAV
• In 1981, Coughlin & Mann found that when there's rounding of the first metatarsal head, oblique/curved position of 1st MCJ, and lateral exostosis at the base of 1st metatarsal causses HAV

Anatomy of the 1st MTPJ & Sesamoid Complex

• Includes Extensor hallucis longus tendon
• Includes Extensor hallucis brevis tendon
• Includes Lateral sagittal hood
• Includes Lateral head, flexor hallucis brevis m.
• Includes Lateral collateral ligament
• Includes Lateral metatarsosesamoid ligament
• Includes Adductor hallucis
• Includes Oblique head
• Includes Transverse head
• Includes Deep transverse metatarsal ligament
• Includes Intersesamoid ligament
• Includes Fibrous plantar pad
• Includes Lateral collateral ligament
• Includes Flexor hallucis longus tendon
• Includes Medial head, flexor hallucis brevis m.
• Includes Abductor hallucis m.
• Includes Metatarsal head
• Includes Crista
• Includes Medial metatarsosesamoid ligament
• Includes Medial sesamoid
• Includes Medial collateral ligament
• Includes Abductor hallucis tendon
• Includes Medial sagittal hood
• Includes Extensor hallucis longus

Clinical Evaluation

• This includes both Nonweightbearing (NWB) AND Weightbearing (WB) exams

Clinical Hallux Evaluation

• This includes a Nonweight Bearing exam and a Weight Bearing exam
• In the History of Present Illness, it is important to note the presence of pain (e.g., duration, description), activities that produce symptoms, whether it is functionally disabling, prior treatments, and the patient's activity/lifestyle.
• Vascular deficits may disqualify a patient from elective surgery and if it is questionable, a full vascular evaluation should be done prior to scheduling.
• Some Neurologic deficits like CP could contribute to HAV deformity
• Dermatologic exam is important for indicating excessive pressure through hyperkeratoses on areas such as the medial HIPJ/MPJ, sub 1st/2nd MPJ, palpable bursas (dorsal, medial, dorsomedial), areas of erythema (medial eminence), and maceration in the 1st interspace

Musculoskeletal Exam

• It is important to evaluate for associated deformities such as Hindfoot valgus, Equinus, Metatarsus adductus, LLD, and Torsional abnormality
• The musculoskeletal exam is to be done non-weight bearing
• It is important to note the planal dominance of deformity: Juvenile HAV is transverse, while adult HAV is transverse & frontal.
• Osseous prominence is also an important detail:
  • The the most common prominence is Dorsomedial
  • a very high IMA is Medial
  • HL/HR or met elevatus is Dorsal.
• Quality of MPJ ROM:
  • Note pain and clicking
• Assess MTPJ ROM including deformed and corrected position:
  • Normal ROM is 60-65° DF test for Unrestricted, Tracking, Trackbound

Evaluation: Unrestricted, Tracking, Trackbound

• UNRESTRICTED
• Shows no joint adaptation, and no soft tissue contractures
• Range of Motion (ROM) in HAV position equals ROM in corrected position
• An example is 55° ROM in HAV is 55° ROM in corrected position
• TRACKING
• Indicates Lateral 1st MPJ soft tissue adaptations
• ROM in HAV position is MORE than ROM in corrected position
• An example is 60° ROM in HAV compared to 45° ROM in corrected position.
• TRACKBOUND
• Soft tissue and joint/osseous adaptations
• Lateral contractures & possible cartilage adaptation of 1st met head
• Deformity cannot manually correct

Hypermobility

• Musculoskeletal NWB exam for 1st MPJ Excursion
• Greater than 10-15 mm with Root/Dynamic Hicks Test is considered hypermobile

Musculoskeletal Exam WB

• Observation includes Hallux position (Rectus, Abutting, Underriding, Overriding), Crossover digital deformities, Hallux interphalangeus, Toe (nail) rotation, Hallux purchase assessment, Gait analysis
• Clinical characteristics typically not seen in children compared to adults with HAV are :
• Associated digital deformities
• Severe DJD -Bursal thickening

HAV Radiographic Evaluation

• Views to order:
  • AP, MO, LAT, and Plantar/Sesamoid Axial
• AP, MO assess IMA, HAA, HIPA, PASA, DASA, TSP, 1st MPJ alignment, Metatarsal parabola, and MPD
• LAT assesses Dorsal exostoses, and Metatarsus elevatus
• Plantar/Sesamoid Axial assesses Sesamoid position & size
• Evaluate the closure of the epiphyseal growth plate at the base of the 1st metatarsal bone to asses if the patient has a status of Physis for Juvenile HAV
• In some under 14 age, they may have an open growth plate
• Some may have a secondary growth plate at 1st met head which changes procedure selection/timing.

HAV Radiographic Angles to know:

• IMA: InterMetatarsal Angle
• MAA: Metaatarsus Adductus Angle
• HAA: Hallux Abductus Angle
• HIPA: Hallux Interphalangeus Angle
• PASA: Proximal Articular Set Angle
• DASA: Distal Articular Set Angle
• MPD: Metaatarsal Protrusion Distance

IMA: Intermetatarsal Angle

• NORMAL in rectus foot = 8-12°
• NORMAL in adducted foot = 8-10°
• Made by Bisection of 1st and 2nd metatarsals
• Bunion Evaluation Rule for Determining Procedures in Rectus Foot, using IMA only:
  • <10 degrees: soft tissue procedure
  • 10-15 degress: met head osteo
  • 15-20 degrees: head or base

  • 20 degrees: met base osteo

MAA: Metatarsus Adductus Angle

• <15° in Normal (rectus) foot
• >15° is considered Adducted foot
• It is noted when there is a Relationship between the long axis of 2nd metatarsal bone and the longitudinal bisection of the lesser tarsus
• Normal adult measures 5-17° per McGlamry
• True IMA = IMA+(MAA – 15°)
• An alternative way to measure MA is Engel's Angle, bisecting 2nd metatarsal bone and bisection of intermediate cuneiform
  • NORMAL angle is <24°
• Compensatory pronation from this may initiate HAV development
• The Ferrari et al, JFAS 2003 revealed MA is present in 55% of those with HAV, and MA is present in 19% of those without HAV
• Look for Appearance of long 1st ray to see adduction of forefoot
• It is important to Recognize these details or improper surgical selection, recurrence, etc may occur.

HAA: Hallux Abductus Angle

• This has a NORMAL range of 10 - 15°
• It is aka HVA (Hallux valgus angle)
• Formed via the Bisection of 1st metatarsal and proximal phalanx of hallux

HIPA: Hallux Interphalangeus Angle

• NORMAL = 0 - 10°
• This is aka HAIA (Hallux abductus interphalangeus angle)
• Formed via the Bisection of the distal and proximal phalanx of the hallux

PASA: Proximal Articular Set Angle

• NORMAL = 0 - 8°
• aka DMAA (distal metatarsal articular angle)
• Formed via the relationship between long axis 1st metatarsal bone and a line connecting medial/lateral points of articular surface of met head
• Radiographic assessment of PASA does not correlate with the actual alignment of the articular cartilage noted intraoperatively as reported by Master Techniques in Podiatric Surgery 2004

DASA: Distal Articular Set Angle

• NORMAL = 0 - 8°
• Rarely abnormal
• Formed from the relationship between long axis of phalanx and a line connecting medial/lateral points of articular surface of base of phalanx

Joint Alignment

• A Congruous alignment is Parallel / close to it
• A Deviated alignment is where the intersection is outside of the joint
• A Subluxed alignment is where the Intersection is within the joint

MPD: Metatarsal Protrusion Distance

• NORMAL = +/- 2mm
• Determined by the length of 1st metatarsal bone compared to 2nd
• A (+) result indicates the 1st metatarsal bone is longer
• A (-) result indicates the 1st metatarsal bone is shorter

TSP: Tibial Sesamoid Position

• NORMAL = 3-4
• The more the tibial sesamoid lateralizes, the higher the number
• Position of sesamoid along the axis of 1st metatarsal
• Measurement should be on AP (or SA)
• TSP 2 – lateral border sesamoid touches bisection 1st metatarsal bone
• TSP 4 - touches bisection of 1st metatarsal bone
• TSP 6 – medial border sesamoid touches bisection 1st metatarsal bone

HAV: Operative Treatment

• The surgical treatment should only be required for certain patients
• It's important to restore functional anatomy, improve pain and prevent progression
• Address these goals to determine the proper surgical corrections: Restore functional anatomy, improve pain and prevent progression
• You must be able to answer what position will my great toe be in after surgery, how long NWB will be necessary, when RTA (return to activity) will be, when the return to work / drive will be, when the return to shoes will be, will this eliminate all symptoms, and what is the recurrence rate for this procedure.

Mayo Block

• This includes the

1. Saphenous nerve
2. MDCN (medial dorsal cutaneous nerve)
3. Deep peroneal nerve
4. MPN (medial plantar nerve)

Soft Tissue Procedures Overview

• Incision placement, capsulotomy, medial capsulorraphy, and lateral release are key components
• Skin Incisions are commonly a dorsomedial linear incision, or may also be a straight medial linear incision
• Anatomical markers should be focused on as EHL, HIPJ, and MTPJ

"The Freshman Nerve": Extensor Hallucis Capsularis

• There is sometimes an Accessory EHL nerve (Extensor hallucis capsularis) that is always medial to the EHL

EHL Tendon

• Often retracted during capsulotomy and bone work,
• Lengthen if EHL tendon is tight/taut (often visible) or HAV deformity is severe
• The "Z-lengthening” method is most common

Capsulotomy

• Follows skin and subcutaneous tissue dissection down to the joint capsule
• Consists of multiple incisions to gain access to the MTP joint
• Can be H Shaped, T-Shaped, or Inverted L

The Lateral Release

• It involves the release of soft tissue structures in the first interspace, lateral to met head
  • 1. DTIL
  • 2. Fibular suspensory ligaments
  • 3. Fibular sesamoid (possible excision)
  • 4. Adductor tendon
• Allows sesamoid complex to “de-rotate," out of valgus
• A debate on whether to perform it or not (some always, never, or dependent on pathology/severity)
• Capsulotomy means to "cut in to the capsule"
• Capsulorraphy means to "cut into capsule", typically removing a wedge of capsule, with goal to tighten the soft tissue envelope, for example ex: Medial capsulorrhaphy

Medial Capsulorrhaphy

• Used in HAV correction to tighten down the (often hypertrophic) medial capsule
• performed after bone work, before closure
• Do not rely on soft tissue correction alone for deformity correction

Phalangeal Osteotomies: Akin Osteotomy Overview

• Distal Akin
• Proximal Akin
• Cylindrical Akin
• Oblique Akin

Distal Akin info

• Wedge cut (apex lateral) in distal aspect of proximal phalanx
• Indications include Abnormal HIPA, Prox Phalanx of normal length, Minimal valgus rotation of hallux, Full ROM of IPJ
• Fixation can consist of Kwire (0.054 common), Staple (10/10/10mm common), Screw (2.4mm common), or Cerclage wire (uncommon, older technique)
• Post Op care is dictated by additional procedures that may include NWB 2-4 weeks with serial XR, or a Return to shoegear after 4-6 weeks

Proximal Akin

• Wedge cut (apex lateral) in proximal aspect of proximal phalanx
• Indications: Abnormal HIPA / DASA, Prox Phalanx of normal length, Minimal valgus rotation of hallux, ROM of IPJ is WNL
• The fixation and post op care is equal to a distal akin

Differences in Oblique and Cylindrical Akin Osteotomy

• Oblique Akin has a more severe cut with easier fixation
• Cylindrical Akin has no hinge left behind, the cylindrical wedge is taken (wider medially) and is Not often done due to instability, difficult fixation, and shortening.

Akin Complications to Know

• Undercorrection
• Overcorrection
• Nonunion
• Shortened hallux
• Hallux extensus

Distal Metatarsal Osteotomies Overview

• Silver
• McBride
• These will be discussed in more detail in HAV Part II: Chevron, Reverdin Green, and Reverdin Green Laird

Silver (1923)

• Ostectomy of medial eminence, a "Bump & Run" to shave off the bump
• This is what many patients think a “bunionectomy" entails
• Indications are HAV deformity with painfree 1st MTPJ ROM, with No need to realign hallux, and Minimal surgery necessitated
• Removal is by "Staking" of the met head
• Fixation: None!
• Post Op is to Consider immediate WB, ROM

McBride (1928)

• Silver bunionectomy + Soft tissue work
• McBride consists of excising fibular sesamoid
  • While Modified McBride will Leave fibular sesamoid, and perform Adductor tendon release (or transfer to reroute under EHL & into medial capsule to reposition sesamoids)
• Indications are HAV deformity with painfree 1st MTPJ ROM, Deviated/subluxed MTPJ (that may have bump pain or sesamoid pain)
• IMA, PASA, DASA should be normal
• Fixation: None! -Post Op: Consider immediate WB, ROM

Fibular Sesamoid

Preserve it if:

• There is no DJD
• There is No plantar pain
• There is a Viable crista
• There is a minimal deviation
• The patient is younger Consider excising if:
• There is DJD of sesamoid
• There is Plantar pain
• There is Eroded crista
• There is Major deviation
• There is Long standing HAV
• The patient is older
• The potential complication of Fibular sesamoid excision is HALLUX VARUS