High tibial osteotomy

Question 1

When is a high tibial osteotomy preformed?

Answer 1

• Varus deformity
• less for valgus
• in
  
  • young active pts <50 yrs in whom arthroplasty would fail due to wear
  • healthy pts with good vascular status
  • non obese pts
  • pain and disability affecting ADLs
  • only one knee comparment affected
  • pt compliant w postop protocol

Question 2

Why is a high tibial osteotomy preformed?

Answer 2

• Angular deformity in the knee leads to abnormal distribution of weight bearing stresses
• can accelerate wear in medial or lateral compartments of knee -> degeneration
• HTO is commonly combined with cartilage restoration procedire to provide better mechanical environment for biological repair

Question 3

What is the prognosis of high tibial osteotomy?

Answer 3

• Varus producing osteotomy
  
  • success rate is 87% pts in 10 yrs
• Valgus producing high tibial osteotomy
  
  • success rate is 50-85% pts in 10 yrs

Question 4

What are the general CI of high tibial osteotomy?

Answer 4

• Inflammatory arthritis
• obese pts BMI >35
• flexion contracture >15 degrees
• knee flexion <90 degrees
• proceedure will need >20^o correction
• patellofemoral arthritis
• ligament instability
• varus thrust during gait

Question 5

describe the mechanical axis?

Answer 5

• line drawn from centre of femoral head to centre of ankle
• line axis should pass just medial to tibial spine

Question 6

What is the presentation of a pt for a high tibial osteotomy?

Answer 6

• Medial or lateral joint pain
• malalignement

Question 7

When is a varus producing osteotomy preformed?

what are the surgical goals of varus- producing osteotomy?

Answer 7

• Done for Valgus knee with lateral compartment degeneration
• deformity <12 degrees or else the joitn line will become oblique

Goals

• upload the involved joint compartment by correcting tibial malalignment
• Maintain the joint line perpendicular to mechanical axis
• CI
  
  • medial compartment arthritis
  • loss of medial mensicus
  • distal femoral osteotomy better if lateral femoral condyle has hypoplasia

Question 8

What are the indications and goals for a valgus producing tibial OSTEOTOMY?

Answer 8

• VARUS knee with medial compartment degeneration
• More common
• best result w 8-10 degrees of overcorrection
• unload involved joint compartment by correcting tibial malaignment
• maintain joint line perpendicular to mechanical axis of leg
• CI
  
  • narrow lateral cartilage space w stress radiographs
  • loss of lateral meniscus
  • lateral tibial subluxation >1cm
  • medial compartment bone loss >2-3mm
  • varus deformity >10 degrees

Question 9

Describe the techniques for valgus producing osteotomy?

Answer 9

• Lateral closing wedge ostoetomy
  
  • most common technique
  • wedge of bone removed from anterolateral approach
  • orif of wedge
  • more inherent stable allow for faster rehab and WB
  • no require for bone graft
• Medial opening wedge technique
  
  • transverse bone cut made in proximal tibia, & wedged open on medial side
  • orif of wedge
  • adv by
    
    • maintaining posterior slope
    • avoids prox tibiofibular joint
    • avoids peroneal n in anterior compartment

Question 10

What are the complications of HTO?

Answer 10

• Recurrence of deformity
  
  • 60% failure after 3 years
    
    • failure to overcorrect
    • pts overweight
• Loss of posterior slope
• Patella Baja
  
  • caused by
    
    • raising tibiofemoral joint line in opening wedge osteotomies
    • retropatellar scarring and tendon contracture
    • bony impingment of patella on tibia
• Compartment syndrome
• Peroneal nerve palsy
• Malunion or nonunion