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

Kazunori Yasuda, MD, PhD Department of Sports Medicine & Joint Surgery

Hokkaido University School of Medicine,Sapporo, Japan

Knee lecture course, Prague 2007

12 yrs.6 yrs.Preop

Kazunori Yasuda, MD, PhDDepartment of Sports Medicine & Joint reconstruction Surgery

Hokkaido University School of Medicine,Sapporo, Japan

Japan

Tokyo

Hokkaido

Sapporo

High Tibial Osteotomy (HTO)

Biological joint-preserving surgery for Medial OA Efficacy of HTO has been established in the 1970’s

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 procedur

e for Medial OA

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

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

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

FTA=185 deg FTA=170 deg FTA=165 deg

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

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

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

Peroneal nerve palsy

Insall (1993): 56/ 804 ( 7.0%) Surgeons should have precise anatomical knowledge about

3-dimensional location of nerve and arteries

Superficial peroneal nerve

Deep peroneal nerveIncorrect direction Correct direction

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?

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

13 yrs.7 yrs.Preop 172 deg

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

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

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?

What factors affect the 10-year results after HTO?

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

The effect of the preoperative age

Insall (JBJS-Am,1984) The results of HTO was worse in the aged patients of m

ore 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

Total Score

Age Good Fair Poor

60 - 69 6 14 16

50 - 59 8 24 14

X2 tests: NS.

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 H

TO• The results were worse in stage IV than in stages II a

nd III

Total Score vs. OA Stage

Total Score

Stage Good Fair Poor

II 2 2 1

III 5 6 5

IV 0 4 4

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

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 　

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

FTA

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 degre

es The mechanical must pass at the center of the lateral plat

eau

11 yrs.5 yrs.Preop 167 degOsteotomy

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

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

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

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

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

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

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

Thank youThank you

Acknowledgement