Evidence-based considerations on a role of HTO for medial OA knees

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Evidence-based considerations on a role of HTO
for medial OA knees
Knee lecture course, Prague 2007

• Kazunori Yasuda, MD, PhD
• Department of Sports Medicine Joint Surgery
• Hokkaido University School of Medicine,
• Sapporo, Japan

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Kazunori Yasuda, MD, PhD Department of Sports
Medicine Joint reconstruction Surgery Hokkaido
University School of Medicine, Sapporo, Japan
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High Tibial Osteotomy (HTO)

• Biological joint-preserving surgery for Medial OA
• Efficacy of HTO has been established in the
  1970s
• Jackson and Waugh JBJS-Br, 1961
• Coventry JBJS-Am, 1965 and 1973
• Insall et al JBJS-Am, 1979
• Currently, the popularity of TKA has increased
  due to various social reasons
• However, HTO remains a significant surgical
  procedure for Medial OA

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3 Topics in my talk

• Current consensus about basic issues on HTO
• Evidence-based considerations
• Current role of HTO
• The best procedure selection to perform HTO

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3 Topics in my talk

• Current consensus about basic issues on HTO
• Evidence-based considerations
• Current role of HTO
• The best procedure selection to perform HTO

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Pain relief mechanism of HTO

• 2 possible mechanisms
• HTO changes load distribution in the knee joint
  due to an alignment correction
• HTO reduces intra-osseous venous pressure in the
  tibia
• The first mechanism is more essential
• Insufficient correction of alignment does not
  have long-term effects for pain relief

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The most ideal candidate for HTO

• Younger than 60 years
• Wishes to maintain an active life style
• Purely medial OA knee
• Varus deformity of less than 15 degrees

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Contra-indications of HTO

• Bi- or tri-compartmental joint destruction
• Lateral OA (clinical results are not predictable)
• Flexion contracture exceeding 10 degrees
• Overall ROM of less than 90 degrees
• Varus deformation of more than 15 degrees

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Complications during and after HTO

• Intra-operative complications
• Peroneal nerve palsy
• Anterior tibial or peroneal artery injury
• Intraarticular fracture
• Post-operative complications
• Nonunion / delayed union
• Infection

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Peroneal nerve palsy

• Insall (1993) 56/ 804 ( 7.0)
• Surgeons should have precise anatomical knowledge
  about 3-dimensional location of nerve and arteries

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Topics in my talk

• Current consensus about basic issues on HTO
• Evidence-based considerations
• Current role of HTO
• The best procedure selection to perform HTO

Is HTO a curative surgery, or a temporary
surgery before TKA?
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Long-term results of HTO

• Hernigou et al JBJS-Am, 1987
• Good evaluation
• 90 at 5 years
• 45 at 10 years
• Yasuda, et al Clin Orthop, 1992
• Good evaluation
• 85 at 5 years
• 63 at 10 years
• The results of HTO gradually degrades after the
  5-year period

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The survival rate of HTO

• If the patients who have undergone HTO complain
  of severe knee pain, TKA must be chosen as a
  revision surgery
• The survival rate of HTO
• Aglietti et al Clin Orthop 2003
• 78 at 10 years and 57 at 15 years
• Nagi et al JBJS-Am 2007
• 92 at 10 years and 58 at 20 years

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Is HTO a curative surgery, or a temporary surgery?

• Remember!
• HTO is commonly recommended for relatively
  younger patients with medial OA
• Currently, the average life expectancy is getting
  longer and longer in advanced nations
• Thus, HTO is a temporary surgery until TKA

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HTO is a temporary surgery until TKA

• This has not a negative meaning
• If the temporary surgery provides pain relief of
  more than 10 years, then it can provide many
  benefits to patients
• We should make effort in surgery to obtain good
  10-year results
• How should we do?

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What factors affect the 10-year results after HTO?

• Possible factors
• Preoperative age
• Preoperative grade of TF and PF OA
• Postoperative FTA

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The effect of the preoperative age

• Insall (JBJS-Am,1984)
• The results of HTO was worse in the aged patients
  of more than 60 years than the other younger
  patients
• Yasuda, et al (Clin Orthop, 1992)
• There were no difference between the aged
  patients of more than 60 years in the 10-year
  results than the other younger patients

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The effect of the preoperative grade of TF and PF
OA

• Yasuda, et al (Clin Orthop, 1992)
• Significantly affected the 10 or more-year
  results after HTO
• The results were worse in stage IV than in stages
  II and III

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The effect of the postoperative FTA

• Yasuda, et al (Clin Orthop, 1992)
• Significantly affected the 10 or more-year
  results after HTO
• In the range of FTA between 160 and 180,
• the more valgus correction, the better in the
  improvement of the evaluation score
• The post-operative FTA is extremely important
• because it is a factor decided by the operator of
  each surgery

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My philosophy on HTO

• HTO is not a minor surgery
• Surgical viewpoint
• Economical viewpoint
• Social viewpoint
• Surgeons should make planning the HTO so that the
  pain-relief time maintains for 10 years or more
  for common OA patients
• Surgeons should select a procedure that can
  precisely correct the FTA to 167 to 169 degrees
  in every patient

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How to make preoperative planning

• Precise physical examinations
• Standing full-length A-P radiogram
• Draw 3 lines,
• Mechanical axis
• Femoral axis
• Tibial axis
• Measure the FTA (femoro-tibial angle)
• Normal value 173 to 175 degrees

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How to make preoperative planning

• To obtain favorable 10-year results, surgeons
  should decide a tibial correction angle
• So that the the FTA will be corrected to 167 to
  169 degrees
• The mechanical must pass at the center of the
  lateral plateau

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Topics in my talk

• Current consensus about basic issues on HTO
• Evidence-based considerations
• Current role of HTO
• The best procedure selection to perform HTO

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What procedure is the best for HTO?

• Many procedures and fixation devises to perform
  HTO
• Surgeons consider the best combination among them
  
• Taking the followings into account
• Precise alignment correction
• Rigid fixation
• Ease of possible TKA

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A problem in possible TKA

• These knees have remarkable deformation and bone
  stock loss of the proximal tibia due to HTO
• Revision TKA is difficult to be performed

After closed wedge osteotomy
After dome-shaped osteotomy
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My preference

• Hemi-closed hemi-open wedge osteotomy
• Aoki, Yasuda, et al (Clin Orthop, 2006)
• The 10-year results of this osteotomy
  were significantly better than the
  closed wedge osteotomy
• Deformation of the proximal tibia is minimal
• Bone stock is completely preserved
• Possible TKA may be easy to be performed

Bone graft
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Many combinations available

• Many procedures
• Closed wedge osteotomy
• Dome-shaped osteotomy
• Hemi-closed/Hemi-open wedge osteotomy
• Open wedge osteotomy
• Many fixation devices and implants
• Staples
• External fixator
• Blade plate and screws
• Plate and screws

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What combination is the best?

• No definite answer to this question
• When you will consider it, you should take
  long-term benefits for patients into account
• Ease to precisely correct the FTA to the targeted
  angle
• Less invasiveness
• Lower rate of complications
• Comfortableness after surgery
• Early return to daily life
• Lower rate of delayed/non-union
• Economical treatment costs
• Ease of revision TKA for the worst case scenario

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Conclusion

• The results of HTO gradually degrades after the
  5-year period
• HTO is a temporary surgery until TKA
• Surgeons should make effort in surgery so that
  the good results maintain 10 years or more
• To obtain good 10-year results, surgeons should
  precisely correct the FTA to 167 to 169 degrees
  in every patient
• When surgeons consider the surgical procedure and
  devises, they should take long-term benefits for
  patients as well as revision TKA for the worst
  case scenario into account

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Acknowledgement
Thank you