High Tibial Osteotomy (HTO) is a surgical procedure that is performed to correct angular deformities of the knee to prevent development or progression of unicompartmental osteoarthritis.
It is predominately done to correct for varus deformities in young patients but can also be done to correct valgus deformities.

• Etiology
  • Use
    • predominately done for varus deformities
    • less common for valgus deformities
  • Angular deformity in the knee leads to abnormal distribution of weight bearing stresses
    • can accelerate wear in medial or lateral compartmentsof the knee and lead to degeneration
    • HTO is commonly combined with cartilage restoration proceduresto provide better mechanical environment for biologic repair

Indications

• young, active patient (<50 years) in whom an arthroplasty would fail due to excessive wear

• healthy patient with good vascular status

• non-obese patients

• pain and disability interfering with daily life

• only one knee compartment is affected

• the compliant patient that will be able to follow postop protocol

 
Symptoms

• pain on the medial or lateral side of the knee

Exam

• knee malalignment

Varus-producing tibial osteotomy

• Surgical goals
  • unload the involved joint compartment by correcting the tibial malalignment
  • maintain the joint line perpendicular to the mechanical axis of the leg
• Indications
  • can be done for valgus knee with lateral compartment degeneration
    • deformity should be <12 degrees or else the joint line will become oblique

Valgus-producing tibial osteotomy

• Goals
  • unload the involved joint compartment by correcting the tibial malalignment
    • A medial unloader brace can be used for therapeutic and diagnostic purposes. If a patient benefits from the brace, they are likely to benefit from surgery.   
  • maintain the joint line perpendicular to the mechanical axis of the leg
• Indications
  • can be done for varus knee with medial compartment degeneration (more common)
  • best results will achieved by overcorrection of the anatomical axis to 8-10 degrees of valgus
• Technique
  • the lateral closing wedge technique
  • the medial opening wedge technique  
  • focal dome osteotomy (concavity proximal)

Prognosis

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