Hallux Varus: Podiatric Surgery II (PM791)

• Hallux Varus is discussed by Christina Pratt, DPM for Podiatric Surgery II (PM791) at Samuel Merritt University.

Terminology

• Hallux Valgus refers to lateral deviation of the great toe.
• Hallux Varus, technically a triplanar deformity, involves the medial deviation of the great toe.
• Triplanar deformity includes:
  • MPJ supination/varus rotation (frontal plane).
  • MPJ adductus (transverse plane).
  • MPJ hyperextension (sagittal plane).
  • HIPJ hyperflexion (sagittal plane).

Etiology of Hallux Varus

• Causes can be:
  • Idiopathic
  • Iatrogenic
  • Trauma
  • Congenital defects.
  • Underlying systemic conditions
• Primary congenital hallux varus consists of varus as the only deformity.
• Secondary congenital hallux varus involves varus with met adductus and hindfoot equinovarus or clubfoot, potentially linked to systemic neuromuscular conditions like polio.
• Systemic conditions that can cause Hallux Varus:
  • Rheumatoid arthritis (chronic inflammation causing joint weakening/subluxation).
  • Psoriatic arthritis.
  • Charcot Marie Tooth Disease.

Role of the Abductor Hallucis

• It is implicated in congenital hallux varus.
• Abnormal insertion of the Abductor Hallucis.
• It remains on the medial side of the foot in some patients.
• Typical insertion is at the plantar medial base of the proximal phalanx, along with the Flexor Hallucis Brevis (FHB).
• Altered insertion changes the directional pull across the MPJ, leading to:
  • More adduction.
  • Less stabilization and flexion.

Iatrogenic Etiology of Hallux Varus

• Includes:
  • Overcorrecting the Intermetatarsal Angle (IMA).
  • Staking of the metatarsal head.
  • Excision of the fibular sesamoid.
  • Aggressive lateral release.
  • Aggressive medial capsulorraphy.
  • Tight/aggressive bandaging post-op.
• Most iatrogenic causes are associated with prior Hallux Abducto Valgus (HAV) surgery.

Overcorrecting IMA

• It is the most common reason for iatrogenic hallux varus after HAV surgery (80%).
• Normal IMA is 8-10°.
• Some surgeons reduce IMA to < 8°.
• Negative IMA is more likely to result in varus.
• Evidence of overcorrection:
  • IMA <8°.
  • Tibilal sesamoid position (TSP) 1-3.

Staking of the Metatarsal Head

• It involves resection of the medial eminence is performed in most HAV procedures.
• Violation of the sagittal groove.
• The Medial proximal phalanx base travels in this groove.
• Problems can arise when too much is resected.
• Evidence of staking:
  • Intra-op violation of the sagittal groove.
  • Intra-op instability/subluxation of MPJ.
  • Tibial peek.

Excision of the Fibular Sesamoid

• The McBride procedure involves the excision fibular sesamoid.
  • Severing the lateral head of FHB.
  • The medial head of FHB gains mechanical advantage.
• The Modified McBride leaves the fibular sesamoid intact with adductor tendon release or transfer.

Aggressive Lateral Release

• Involves the release of 4 structures at the lateral MPJ.
• Requires careful, meticulous dissection and identification.
• Some surgeons resect/remove more structures, like the "interspacectomy".
• Includes release of the:
  • Lateral capsule
  • Lateral head FHB
• You should not cut both the lateral head of the FHB and adductor hallucis tendon
• This would allow the medial structures to overpower.
• The Lateral Release includes:
  1. DTIL
  2. Fibular suspensory ligaments
  3. Fibular sesamoid (possible excision)
  4. Adductor tendon

Aggressive Medial Capsulorraphy

• Tightens down the medial capsule following HAV correction.
• Removing too much tissue can overtighten the medial side.
• this leads to medial deviation

Tight/Aggressive Bandaging Post-Op

• Bandaging/dressings are not always benign.
• It is common to bandage the hallux in an overcorrected position.
• Prolonged position can allow for adaptive soft tissue changes.
• In combination with other mistakes, exacerbates deformity.

Hallux Varus Clinical Evaluation.

• HPI includes:
  • Prior HAV surgery.
  • Pain with footwear
  • History of neuromuscular disorders and ligamentous laxity.
• Investigate details of prior HAV surgery.
  • What procedures were done?
  • What was the look of the toe after surgery?
  • How did the post-op recover?
  • Were there any issues of being compliant?
• PE is similar to HAV evaluation and includes:
  • Degree of MPJ ROM.
  • Pain with MPJ ROM.
  • Crepitus.
  • Reducible deformity or rigid deformity.
  • Hallux toe purchase (often non-purchasing).
  • Lesser digit adduction (following the hallux).
  • Medial hallux callusing.
  • Transfer metatarsalgia callusing.
  • Nail changes.

Hallux Varux Imaging Evaluation

• X-Rays show:
  • Adduction of the hallux.
    • MPJ position.
    • Deviated / subluxed / dislocated.
    • Arthritic changes to MPJ.
      • Flattening of base proximal phalanx.
      • Asymmetric joint space narrowing.
      • Peri-articular osteophytes.
      • Subchondral sclerosis.
      • Erosive/cystic changes.
  • Long or short 1st metatarsal.
  • Fibular sesamoid present.
  • TSP (medial position).
  • IMA (negative).
  • HAA (negative).
  • Medial eminence staking (if h/o HAV surgery).

Joint Alignment Terminology

• Congruous/Rectus are parallel/close.
• Deviated refers to it's instersection outside of the joint.
• Subluxed refers to it's intersection within the joint.
• Dislocated is a lack of joint contact.

Hallux Varus Conservative Management

• There are minimal options.
• Footwear changes (wide toebox) and taping (if reducible) may help.
• Splinting hallux out of varus position is helpful if recognized very quickly post-op.
• There is Variable long-term outcome.

Hallux Varus Surgical Management

• Includes:
  • Soft tissue procedures.
  • Osseous procedures.
  • Combination of both.
• What caused it and can the cause be surgically reversed are important questions to ask.

Soft Tissue Procedures

• EHL Tendon Transfer:
  • Resect from the distal phalanx insertion.
  • Insert into the lateral base proximal phalanx.
  • Performed with HIPJ arthrodesis.
  • It may avoid need for HIPJ arthrodesis, but it is often too thin a tendon for this.
• Abductor Hallucis release:
  • Lengthening or transfer consists of resecting from insertion at plantar medial base proximal phalanx (with FHB).
  • Relieves the adductory pull on the hallux.
  • Better results are achieved in cases of a medial insertion.
  • Must have little to no joint (osseous) adaptive changes.
  • Assess if it provides enough correction.
  • The tendon may also be too short to transfer.
• Tibial sesamoidectomy:
  • Uncommon as the primary surgical option.
  • Release of the medial head of FHB relieves medial structure dominance.
• Lateral capsular tensioning:
  • Newer fixation options allow for recreation of lateral capsular strutures.
  • There is ability to tension as appropriate to achieve position.

Osseous Procedures

• Keller resection arthroplasty:
  • Described by Keller (1904) for hallux valgus correction.
  • It is now commonly used (still not first choice) in hallux limitus.
  • Involves the resection of 1/3 of the base proximal phalanx.
  • Can also apply to hallux varus correction, but with caution in an already unstable MPJ complex.
  • May perform with soft tissue work.
• Reverse Chevron osteotomy:
  • Common joint salvage option in cases of staking of the met head.
  • Performed using the same technique as a traditional chevron osteotomy.
    • The capital fragment is pushed medially instead.
    • Reverse Reverdin osteotomy has been described in "reverse correction".
• Reverse osteotomy procedures:
  • Reverdin
  • Chevron.
  • Scarf.
  • OBWO.
  • CBWO.
• 1st MPJ Arthrodesis:
  • Very common in hallux varus correction of multiple etiologies.
  • Severe loss of ROM with DJD is the only option.
  • Allows for correction of triplanar components of deformity.
  • Predictable position
  • Reliable outcome.

Botox for Hallux Varus

• Some literature supports the use of neurotoxin.
• Requires repeated injections.
• Limited success.

Hallux Varus Pearls

• Accurately determine the cause of hallux varus.
• The status of the MPJ is critical to procedure selection.
• There are limited conservation options
• Soft tissue procedures are often adjunct to osseous correction
• 1st MPJ arthrodesis is the standard to correct all aspects of the deformity.

Hallux Varus, a triplanar deformity, involves medial deviation of the great toe, including MPJ supination/varus rotation, adductus, and hyperextension, plus HIPJ hyperflexion. Etiologies range from idiopathic to iatrogenic, trauma, congenital defects, and systemic conditions like rheumatoid arthritis.