1. Evidence-based considerations on a role of HTO for medial OA knees
Knee lecture course, Prague 2007
Evidence-based considerations on a role of HTO for medial OA knees
12 yrs.
6 yrs.
Preop
Kazunori Yasuda, MD, PhD
Department of Sports Medicine & Joint Surgery
Hokkaido University School of Medicine,
Sapporo, Japan

2. Hokkaido Sapporo Japan Kazunori Yasuda, MD, PhD
Department of Sports Medicine & Joint reconstruction Surgery
Hokkaido University School of Medicine,
Sapporo, Japan
Japan
Tokyo
Hokkaido
Sapporo

3. 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 procedure for Medial OA

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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 nerve
Incorrect direction
Correct direction

11. Current consensus about basic issues on HTO
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?

12. 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
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

13. 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

14. 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

15. 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?

16. What factors affect the 10-year results after HTO?
Possible factors
Preoperative age
Preoperative grade of TF and PF OA
Postoperative FTA

17. 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
Total Score
Age Good Fair Poor
X2 tests: NS.

18. 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
Total Score vs. OA Stage
Total Score
Stage Good Fair Poor II
III IV

19. 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

20. 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　

21. 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

22. 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
Osteotomy
11 yrs.
5 yrs.
Preop
167 deg

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. 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

30. Acknowledgement
Thank you