M. Mardani Kivi Guilan University of Medical Sciences

 Patient selection  Correct diagnose of location,directing and magnitude of deformity  Angle of correction  Surgical technique  Over-correction vs. Under-correction

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

 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

◦ 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 ◦ We should make effort in surgery to obtain good 10-year results

 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

 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

 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

 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

 Location  Extra-articular ◦ Femur ◦ Tibia  Intra-articular ◦ Joint line obliquity ◦ Ligamentous laxity ◦ Articular cartilage deficiency ◦ Osseous deficiencies

 Direction  Sagittal ◦ Flexion ◦ Extension  Coronal ◦ Varus ◦ Valgus  Rotational  Magnitude  Mild (<10 degrees)  Moderate (10 to 20 degrees)  Severe (>20 degrees)

 Tibial  Lateral closing wedge  Medial closing wedge  Medial opening wedge ◦ Graft ◦ Staple  Distraction histogenesis  Barrel vault (dome) osteotomy  Oblique metaphyseal wedge

 Femoral  Medial closing wedge ◦ Medial fixation ◦ Lateral fixation  Oblique metaphyseal wedge  Lateral opening wedge  Lateral closing wedge

 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

 Full length film of the leg is ideal to assure the restoration or overcorrection of the mechanical axis  The simplest method for determining the angle of correction involves drawing a line from the center of the femoral head to the lateral margin of the tibial spine and then a line from the lateral tibial spine to the center of the ankle.  The angle from these 2 lines represents your angle of correction

Lower limb malalignment Lower limb malalignment Coronal Sagittal Rotational

Alignment Collinearity of the hip, knee ankle Orientation Position of each articular surface relative to axes of the individual limb

Joint orientation angles & nomenclature mLDFA=85-90° mMPTA=85-90° JLCA=0-2° mLPFA=90° mLDTA=89°

incorrect correct

MAD>15 mm medial mLDFA>85-90° Femoral varus deformity mMPTA<85-90° Tibial varus deformity Varus deformity

MAD>10mm lateral Valgus deformity mLDFA<85-90° Femoral valgus deformity mMPTA>85-90° Tibial valgus deformity

TT-TG TT-TG≤15mm

TFA≤15

Physiologic value 23.5±5.1° ext

1. In malalignment evaluation consider hip, knee and ankle joints. 2. Insist on proper radiologic assessment. 3. Consider malalignment in sagittal, coronal and rotational plane. 4. Be careful of tibial slope in HTO.

 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

 3-6 valgus  valgus  6-14 valgus  Realignment osteotomy about the knee continues to meet many of the original expectations. Although the current indications are relatively narrow, the surgeon should be confident in choosing corrective osteotomy when appropriate criteria are met. Long-term results linked with careful patient selection, accurate surgical technique, and appropriate postoperative alignment portray a favorable outlook for these procedures, particularly because the population at large is more active and is expected to have increasing longevity.

The weight-bearing line method divides the tibial plateau from 0% to 100% (medial to lateral) to determine the desired intersection coordinate of the mechanical axis through the knee joint. Wedge height is calculated by tracing the wedge on the radiograph with the desired angle of correction. The wedge height measurement on the radiograph is then normalized by the radiographic magnification present.

Standing full-length radiograph of an active 46-year-old woman with localized medial compartment knee pain. Note the tibial distal mal- union.

Fujisawa point

 In a femur with pathologic femoral varus or valgus, the femoral deformity is determined at the center of angulation of rotation (CORA) located at the intersection of the proximal and distal anatomical axes of the femur.

 The CORA method of planning has revealed the relationships between the ACA, CORA, and osteotomy level. These are summarized as osteotomy rules 1 and 2 and a corollary to these rules. Osteotomy rule 1 states that angular correction with the ACA and the osteotomy passing through the CORA leads to complete colinear realignment of the proximal and distal axes of the bone, without displacement of the bone ends.

 Osteotomy rule 2 states that when the ACA passes through the CORA but the osteotomy is at a different level, complete colinear realignment of the proximal and distal axis lines occurs, with displacement of the bone ends. Finally, the corollary to these osteotomy rules is that when the ACA and osteotomy do not pass through a CORA, a secondary translation deformity of the proximal and distal axis lines results.