Step-By-Step Operative Checklist

(Aligned with Althoff & Gomoll, 2026)

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1. Preoperative Phase

A. Confirm Indications

• Varus deformity with medial compartment overload
• Deformity >3° from mechanical neutral
• Meniscal root tear / deficiency, focal cartilage defects, unicompartmental OA
  

B. Screen Contraindications

• Lateral compartment degeneration (contra for OW-HTO)
• Chronic lateral laxity not accounted for (1 mm widening ↓ correction by 1°)
  

C. Preoperative Imaging

• Full-length standing hip–knee–ankle films
• Assess joint line convergence & slope
• MRI:
  • Lateral meniscus & cartilage
  • Popliteal vessel variants (aberrant anterior tibial artery)
    

D. Plan Correction

• Choose hinge: anterolateral to protect slope
• Adjust for lateral laxity
• Ant. gap ≈ ½ posteromedial gap for slope neutrality
  

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2. Patient Positioning

• Supine
• Radiolucent table
• Paint roller / bolster under heel (maintains knee extension → slope control)
  
• Tourniquet optional (author preference usually without)

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3. Surgical Approach

A. Incision

• Medial vertical or midline → preserves TKA options
  

B. Superficial dissection

• Identify pes tendons
• Expose sMCL
• Incise fascia posterior to sMCL OR gracilis-based transverse incision
• Subperiosteal posterior dissection to fibular head
  

C. Posterior protection

• Place blunt retractor posterior to tibia
• Second retractor behind patellar tendon
  

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4. Guidewire Placement

• Under fluoroscopy, aim guidewire toward tibiofibular joint
  → minimizes risk of lateral hinge fracture
  
• If wire crosses distal to tubercle → plan retrotubercular countercut
  (preferred technique in article)

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5. Osteotomy

A. Cortex Cuts

• Use saw for:
  • Anterior cortex
  • Medial tibial body
• Switch to osteotome for posterior cortex
  → prevents unwanted posterior slope increase
  

B. Maintain hinge

• Stop ~1 cm medial to lateral cortex at planned hinge point
• Ensure complete posterior cut (fluoro)

C. Biplanar (optional)

• Consider for patella baja risk — retrotubercular cut attached proximally

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6. Opening the Wedge

A. Controlled Opening

• Use stacked osteotomes:
  • First osteotome proximal (protects hinge)
  • Subsequent ones distally
    

B. Protect slope

• Maintain:
  • Posteromedial gap = target
  • Anterior gap = half of posterior gap
    

C. Confirm Alignment

• Fluoro: femoral head centered, avoid parallax
• Adjust correction in real time

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7. Graft / Void Management

• Options: autograft, allograft, no graft
• Literature: No substrate proven superior
• Author preference: structural allograft
  
• Consider graft for gaps >10 mm to prevent nonunion

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8. Fixation

• Angular-stable locking plate (posteromedial placement)
  → minimizes deforming forces
  
• Confirm:
  • Screws distal then proximal
  • Plate in posterior half of tibia to avoid slope change
• Hardware removal commonly needed but safe after 1 year
  

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9. Intraoperative Checklist for Complications

A. Lateral hinge stability

• If unstable or fractured:
  • Place staple / plate across hinge
    

B. Tibial plateau propagation

• If fracture occurs:
  • Reduce
  • Place parallel subchondral screws
  • Re-open osteotomy
    

C. Posterior slope check

• Confirm slope compared to preop
• Use wedge plate if needed
  

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10. Closure

• Repair MCL sleeve (if cut)
• Reapproximate pes fascia
• Layered closure
• Vancomycin powder along plate (author preference)
  

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11. Postoperative Protocol (High Yield)

• Early ROM encouraged
• Partial WB → progress per fixation stability
• Avoid prolonged immobilization (prevents patella baja and stiffness)
  
• Vitamin D correction for union optimization