HIGH TIBIAL OSTEOTOMY

• Type of realignment osteotomy• Fundamental goals of the procedure are to

unload the diseased articular surface and to correct angular deformity at tibiofemoral articulation

• Due to success of TKR, number of HTO came down.

• Renewed interest in recent times due to1. Prevalence of physiologically young active

Pts with medial comp OA.2. Advent of new techniques for performing

the procedure.3. Need to concomitantly correct the

malalignment when performing chondral resurfacing procedures.

DRAWBACKS

• Not an ideal option for Pts with significant bicomp & tricompartmental OA.

• Results of the procedure progressively detoriates.

INDICATIONS

• Gonarthrosis in Pts with varus limb alignment.• Gonarthrosis in Pts with valgus limb

alignment.• Aduit osteochondritis dissecans.• Osteonecrosis [Medial condyle]• Posterolateral instability.

CONTRAINDICATIONS• Dffuse nonspecific knee pain• Primary compliant of patellofemoral pain• Menisectomy in the compartment intended

for Wt bearing.• Arthrosis in the compartment intended for Wt

bearing.• Inflammatory arthritis, chondrocalcnosis• Unrealistic Pt expectation.

• Medial compartment tibial bone loss of > 2 or 3 mm

• Flexion contracture > 15*

RELATIVE C.I

• Age older than 60 yrs• ROM arc less than 90 degrees• Obesity [> 80 kg]• Severe arthrosis• Tibiofemoral subluxation [> 1 cm]• Moderate to severe ligamentous instability.• ACL tear.

CLASSIFICATION

• Gariepy and Coventry: lateral based closing wedge osteotomy, proximal to anterior tibial tubercle.

• Slocum et al: Modification of coventry, leaving a posterior lip of cortex in proximal tibial segment.

• Macquet: Barrel vault or dome osteotomy, stabilised with Ext. compression device

used for larger deformities and for knees with tibiofemoral subluxation.

• Wagner: Oblique metaphyseal P.T.O just below the tibial tubercle, displacement osteotomy of proximal tibia for larger defects.

• Varus deformity up to 10* off the mechanical axis transverse laterally based closed wedge P.T.V.O

• Up to 20* Wagner’s oblique P.T.O• > 20* dome osteotomy of proximal tibia or

metaphyseal osteotomy of proximal tibia.

VARUS OSTEOTOMY

• For isolated lateral comp, OA & valgus knee.• Valgus up to 12* can be corrected.• For deformities with > 12* valgus, distal

femoral osteotomy is preferred in order to maintain Jt line parellel to floor.

Closing wedge osteotomy

• Most commonly performed HTO• C.I: when the affected limb is shorter than

other side• Fixation: plate system / staples.• ADVANTAGES:1. More aggressive weight bearing and

rehablitation2. Doesn’t require a graft.

• DISADVANTAGES1. More difficult to control tibial slope often

decreased.2. Intraop adjustments more difficult.3. Proximal tibiofibular Jt violated4. Increased risk of peroneal N. injury5. Alters the shape of proximal tibia with

implications for TKR.

6. Bone loss and shortening7. May alter patellar Ht.

Opening wedge osteotomy

• Now a days commonly used.• Indicated when affected side is shorter.• Fixation: Plares, external fixator or spatial

frame [larger corrections], bone graft alone.

Advantages

• Potentially simpler• Avoids proximal tibiofibular jt• Avoids peroneal N.• More control of multiplanar correction• Avoid anterior compartment• No bone loss.

disadvantages

• Less aggressive Wt bearing/ rehablitation• Often requires a graft with potential

implications of healing/ union• May overlengthen the limb• May alter the patellar Ht.

Osteotomy site

• Proximal to the tibial tuberosity is preferred• Quadriceps can exert compressive effect at

O.S• Cancellous bone allows faster healing• Osteotomy generally performed 1.5-2 cm

distal to the Jt line.

• More proximal resection causes proximal fragment to be too thin and at a risk of intraop # or AVN.

• Osteotomy too distal can disrupt the extensor mech at T. tubercle.

Wedge size

• As a rule of thumb, removing 1 mm of tibial wedge will provide 1 deg of correction.

• This is precisely true for a tibia which is 56 mm wide.

X ray

• Full length supine and weight bearing AP X rays are used to determine the desired amount of correction.

• Radiographic methods for planning:1. Mechanical axis method2. Anatomic axis method3. Supine over correction method.

Supine over correction method

• Based on the permise that patients whose varus deformity is based in part on ligamentous laxity needs less correction than Pts with out laxity.

• Assumption: mechanical axis value just prior to heal strike is similar to supne mechanical axis

• Measure the supine mech axis and add 10 degrees of correction.

Management of fibula

• Proximal tibiofibular jt will prevent valgus correction unless fibula is shortened or tibiofibular lig are removed.

1. Transection of tibiofibular ligaments [preferred tech]

2. Fibular head transection3. Fibular transection.

complications

• Patellar baja [lateral closing wedge o. associated with high incidence], arises due to contracture of patellar lig.

• Fracture of the far cortex or the intra-articular #. [restrict osteotomy to 10 mm of far cortex]

• Osteonecrosis of prximal frag.

• Non union • Neurological injuries. [1-10%] when ext, fix is used, osteotomy of fibular

head, corrections greater than 15*.• Incomplete correction• DVT• Compartment syndrome.

TKR vs HTO

• Disease distribution• Age• Patient activity level. physiologically young high demand Pts are

suitable candidates for HTO.

• Long term studues indicate clinical success of HTO detoriate with time.

• Most studies suggest that more than 50% HTO remain effective at 7-10 yrs.

• Arguably TKR canbe successfully postponed for at least 7-10 yrs in most appropriately selected pts.