Hallux Valgus and Bunion Correction: Osteotomies of the Proximal Phalanx (Aiken Procedures)

Introduction

The discussion continues on hallux valgus and bunions, focusing on osteotomies of the proximal phalanx (Aiken procedures) to correct structural deformities.
Decision-making is driven by clinical and X-ray evaluations, addressing both soft tissue and structural issues.

McBride Bunionectomy

Addresses soft tissue issues like tracking and valgus rotation of the toe.

Radiographic Evaluation

Includes full foot DP, lateral, and sesamoid axial X-rays.

Osteotomies of the Proximal Phalanx (Aiken Procedures)

General Use

Correct structural deformities within the proximal phalanx.
Primarily address hallux interphalangeus, elongated proximal phalanx, and dorsal alignment issues.

Types of Aiken Osteotomies

Proximal, distal, and mid-shaft, named after Aiken.

Clinical Presentation

Often involves lateral deviation of the toe towards the second toe without a significant bunion.
Structural deformity in the proximal phalanx is the primary cause (hallux interphalangeus, dorsiflexion, or elongated phalanx).

Hallux Interphalangeus

The distal phalanx is deviated towards the second toe.
The medial side of the proximal phalanx is elongated compared to the lateral side.

Correction Strategy

Involves taking wedges of bone to balance the length relationship.
Closing wedges are used.

Original Aiken Procedure

Removal of the medial eminence (bump).
Osteotomy in the proximal phalanx to move the big toe towards the midline.
Historically included removing the base of the proximal phalanx, which is no longer practiced.

Medial Closing Wedge Osteotomy

The wedge is wider on the medial side to address medial elongation of the proximal phalanx.
Corrects structural deformity within the proximal phalanx.

Transverse Osteotomy

Involves cutting straight across the proximal phalanx.
Wedge removal on the medial side shortens that side.

Preoperative Planning

Involves templating to predict the amount of bone to be removed.
Also involves intraoperative assessment and X-rays.

Surgical Technique

The bone saw is used from dorsal to plantar or medial to lateral.
The wedge is removed, closing the angle on the lateral side.
The hinge on the lateral side is often kept intact for stability.
Fixation (wire, bone screw, staple) is used to stabilize the osteotomy.

Post-operative Result

The toe is in a more rectus (straight) position.

Structural Deformities Addressed

Elongated proximal phalanx.
Hallux interphalangeus (more common, deformity in the distal one-third of the proximal phalanx).
Dorsiflexion (less common, deformity in the proximal one-third).

Center of Axis of Rotation (CORA)

The center of axis of rotation is where the bisections of the distal and proximal phalanx intersect.
$CORA$ determines the location to remove the wedge.

Adjunct Procedure

Aiken type osteotomies are often adjuncts to bunion surgery, combined with McBride procedures.

Combination with Other Osteotomies

Can be combined with distal, mid-shaft, or proximal osteotomies.
Corrects multiple structural deformities simultaneously.

Examples

McBride bunionectomy with mid-shaft osteotomy for structural deformity.
Distal osteotomy to correct mild elevation in the intermetatarsal angle and proximal phalanx deformity.
Corrects high intermetatarsal angle (IMA), high HI, or high dorsiflexion, requiring multiple osteotomies.

Specific Aiken Procedures

Distal Aiken

For abnormal HI angle or hallux interphalangeus.
Medial closing wedge in the distal aspect of the proximal phalanx.

Clinical and Radiographic Diagnosis

Skin lines over the IP joint are oblique.
HI angle greater than 10 degrees is generally considered pathologic.
Clinical assessment in weight-bearing and non-weight-bearing positions

Surgical Technique

The type of surgical fracture dictates fixation options (pin, screw, staple, mini plate).
Bone screws create interfragmental compression.
$Compression <br>eq Transverse Fracture$ due to screw orientation issues.

Oblique Aiken

Medial closing wedge done in an oblique fashion.
Allows for placement of a compression screw perpendicular to the fracture.
Enables earlier mobilization of the big toe joint.

Advantages of Oblique Aiken

Earlier mobilization of the joint, decreased rehab time, and reduced scar tissue formation.

Surgical Steps of Oblique Aiken

Wedge removal based on structural deformity.
Hinge kept intact.
Reciprocal planing to weaken the hinge, and compression screw insertion.

Cylindrical Aiken

Used for structurally elongated proximal phalanx.
Shortens the proximal phalanx to decompress it.
Can be combined with HI or dossa correction.

Procedure

A cylinder of bone is removed from the proximal phalanx.
Location of bone removal depends on HI or dossa.
Parallel cuts of bone may be performed for shortening without HI or dossa.

Cylindrical Aiken Fixation

Transverse fractures stabilized with pins; newer fixation methods include plate bowl (screw and staple combination).

Clinical Example

In revisional bunion surgery:
*Scarf bunionectomy addresses intermetatarsal (IM) angle.
*Cylinder of bone removed proximally to handle elongation and possibly some dorsiflexion.

Proximal Aiken

Proximal medial closing wedge for high DSA (dorsal articular set angle).
Rare procedure, for structural deformity of the proximal phalanx, not hallux abductus.

Indications & Considerations

Addresses structural deformity (dossa, hallux interphalangeus, elongated proximal phalanx).
Does not treat tracking but structural deformity.

Sagittal Z Osteotomy

For elongated proximal phalanx with no HI and no dossa.
Cut a Z into the bone to slide straight back. Placing a bone screw can cause interfragmental compression.

Renault Procedure

(Antiquated) Taking out the base of the proximal phalanx.
Considered obsolete.

Cautions

Be careful not to use osteotomies to simply make the toe "look" straighter rather than correcting the primary structural or cartilaginous issue.
Cheater Aiken utilized to try and help create a perfect cosmetic appearance to the toe
Can lead to MP joint breaking down and becoming arthritic.

Operative Intervention Examples

35 y.o. pt. with painful deviated big toe joint, normal IM angle, hallux abductus angle 30 degrees, and hallux interphalangeus 17 degrees: McBride and distal Aiken
35 y.o. male with painful deviated big toe joint, high dossa, no IM angle, and tracking: McBride & Proximal Aiken
Elongated proximal phalanx with no dossa and no hallux interphalangeus: Sagittal Z or a cylindrical Aiken

Distal Osteotomies

General Information

Distal osteotomies are commonly used for hallux valgus management due to their inherent stability, allowing immediate weight-bearing in a surgical shoe.
Focus: correction of IM angle (<15 degrees), track-bound joint/dysfunctional PASA, and some simultaneous plantar flexion in cases of limitus.
Always performed with McBride bunionectomy components (capsulotomy, bump shaving, lateral release)
General Indications: IM angle less than 15 degrees, ability to treat track-bound joints or dysfunctional PASA, consideration to treat possible shortening risks, and all are performed in conjunction with McBride bunionectomies.

Distal Osteotomies: Considerations

Limit how much can move based on metatarsal width
Most have inherent stability (aka the design of the surgical fracture), allowing patient to immediately bear weight and not have to be non-weight bearing post op
Proximal has period of 3-6 weeks minimum for non-weight bearing (compliance is terrible, elevate and malalign if pt does not listen).

Austin Bunionectomy

Austin bunionectomy (horizontal V osteotomy in the distal segment of the first metatarsal).
60-degree angle. Distal fragment referred to as capital fragment. This is moved over laterally.

Fixation:

Traditional: hard to put a bone screw.
Altered: now dorsal arm is more acute to allow bone screw ability.

Considerations:

*Apex should be on superior surface of cartilage.
*Inferior surface where osteotomy is supposed to be.
*Unilaminar, meaning fixed for interment angle. Need to ensure NO degenerative joint disease of the first MP joint

Moderate increase in IM angle up to fifteen degrees.
Must consider metatarsal width at the level of the neck to consider transposition value.
*Must have normal PASA. Toe can have tracking (due to the components of MB), but NOT track bound (due to deviant articular cartilage)
Corrects IM angle only. Will be cutting differently to correct some PASA the same time. Normal metarasal protrusion, as it has some shortening occurring when doing it.
Should have somewhat of a congruent joint preoperatively. Will be talking modifications of the Austin.

Traditional Austin:

*60 degrees and is for IM angle, while also performing components of the broad bunionectomy

Relative reduction

Remember that the apex of core was was back proximal
Essentially putting deformity in the bone, to create somewhat of a congruent joint
Not fixing bunion back where real core is; see this well when do lap as get close to fixing it.

Apical Axis Principle:

Crucially important to minimize shortening.
If cut directly perpendicular to second metatarsal, we minimize shortening.
When you start in learning with the residents, we labor through putting guide pins in to align saw blade. This is supposed to minimize shortening.
The biggest is pitfall is if you cut it from distal medial to proxy lateral, as this shortens.

Surgical technique (Austin-uni):

Capsulotomy→ dissect capsule→ cut collateral ligament. Take bump off (flat surface; easier to do osteotomy).
Bump needs to also maintain the longitudinal groove.
Reposition the sesamoids back.
Will usually fixate, stabilize. Cut the capitate, release soft tissue shave the pump for this

Osteotomy steps of Austin:

Put slightly from superior to. Will allow even just a millimeter of room even to help plantarflex slightly.
MUST USE AXIS PRINCIPLE TO MINIMIZE SHORTENING WHEN PERFORMING THE UNIT CORRECTIONAL OSTIN OF THE INTERMETARSAL ANGLE ONLY.
After this process, shave of the remaining medial overhang-do not overcorrect. Usually remodels alone.

Axis:

Put slightly from superior to. Will allow even just a millimeter of room even to help plantarflex slightly.
APICAL AXIS IS CRUCIAL TO MAINTAIN LENGTH AND TO MINIMIZE SHORTENING.

Modifications of Austin

Bicoorrectional Austin

Transverse Plane Deformity: two things. To treat more deviated articular cartilage.
Clinically, someone would have probably more of a track bound joint with IM angle and mild to moderate angle
Abnormal PASA/dysfunctional PASA: move it over and tilt it. (the way you are cutting it).
If move it over, and put the base of the phalanx back there, we haven't done anything for the articular cartilage you have GOT TO DO SOMETHING to FIX that, too.

Technique:

Take away a little bit more bone (not cutting all the way through) on medial. Allow head tilt (centralized head tilt).
Intraoperative decision. Open big toe, because find the cartilage has deviated. You fix the issue. Can change in the middle of the procdeure. IntRAOP that the issue is revealed and fix it.
Put a piece on the top, only part of the way through. More bone medial than lateral to centralize and fix articular cartilage
I have to say take a look at PASA. Bone good, tilt (break+move)
Not going to go through the center of osteotomy. Allows cartilage with centralization of base and proxy. More bone comes out of medial side than the lateral side, giving the ability to fix it with a bone fix (in photo).

Biplane Austin (Youngswick)

Two different planes.
Transverse + Sagital planes = IM angle + Tilting Down
Mild Metatarsal Elevation → Plantar Flex it
Get decompression→ change axis in motion→ greater level of doorsiflexion
In OR for this, will see planning with bone screw to follow. Parallel cut on second cut (wafer to take out (dorsally- allows to plantar flex+take tension off). Then move axis/change axis through plantar flexion/parallel cut through parallel to the second

Kalesh Austin

Excessive Transposition- dorsal arm and 50 (up into diaphysis)
Increases trans position via bone-to-bone contact; can only occur w/ 2x 2.7 screw fixation
Remember that this is distal, and intrinsically stable, so pt. leaves hospital knowing and should be able to manage right away (heel prop shoe; no propulsion); no need to be NWB

Reverdin Procedure

Distal medial closing wedge
Used if transverse plane def (deviation articular/cartilage) + NO im angle angle→ rarely see just angle only
trying to get the cartilage back from deviated back + get from being rectus
Cart deviation= smaller size/ smaller wedge needed → length of the first meta tarsal needs to compensate for shortening

Distal cut parallel articular cartilage, axis proximal cut perpendicular to metatarsal to that deviation

DO NOT break cortex in this procdeure
Template to calculate bone remova;
With digital x rays, figure more bone needed to remove; see how it straightens in process/OR, make ultimate and most definitive answer (intraop)-not just one angle and done (per surgery to fix one thing that had to do mult.)
Take in between the metal and cart (as saw) and protect the sesamoid bones for being cut when going to the top

Green mod revardin:

make sure is a platarcut to avoid the issue of the sesamoid bone
Cut out in that triangle where the angle exists to protect. The Reverdin osteotomy involves a wedge resection to realign the articular cartilage and has a plantar cut to protect the sesamoids. The Reverdin Laird involves shifting after wedge resection and alignment of the medial bone while also fractureing and transposing that cap fragment (all same indications and the bicaust) with a plant