DoTechRecent

Double Osteotomy

Technique

The osteotomies are adjacent to the joint in the juxta-articular cancellous bone. That is, in the tibia, above the tibial tubercle, and in the femur, through the articular cartilage at broadest part of the femoral condyles within the knee joint.

Operative Technique
With the patient supine, the limb exsanguinated and the surgeon standing on the contralateral side, a straight mid-line longitudinal anterior skin incision is made from below the tibial tuberosity to above the upper border of the patella.

Fig 1

The incision is deepened through the capsule, medial to the patella, down to bone, without reflecting skin flaps. Damage to the vastus medialis belly is avoided by extending the incision proximally in the rectus tendon. The patella and patellar tendon are dislocated laterally and the tibial condyles exposed subperiostially, separating from bone the upper 25 mm (1 inch) of the origin of the anterior tibial group of muscles. The knee is flexed fully and remains so whenever the osteotome is in use to ensure that the popliteal artery drops away (Fig 2) from the posterior joint capsule and so is less vulnerable to damage. Never osteotomise with the knee straight.

Fig 2. The popliteal vessels have nothing between them and the knee joint.
They are in danger from the osteotomes. Osteotomy MUST be done with the knee flexed. The vessels fall well away

Tibial Osteotomy
The tibia is osteotomised above the insertion of the patellar tendon,
25 mm (1 inch) distal to the articular margin of the tibia.
With the knee flexed, bone levers are passed on either side of the tibial
condyles, a narrow osteotome, placed vertically cuts through the lateral cortex and then a broad osteotome is driven horizontally across from the medial cortex to meet the narrow osteotome already in position.(Fig 3)

Fig 3. A narrow osteotome vertical through the lateral
cortex and meet it with a broad one from the medial side

The posterior tibial cortex has probably not been divided, and the
osteotomy is completed by hinging the tibial condyles on the posterior cortex and so breaking it. The hinging is achieved by inserting a narrow osteotome and levering the transverse osteotome which has not yet been removed, see figure 4.
If deformity is to be corrected, the knee is extended and manipulated into the desired position; one side of the osteotomy crushes and the other opens.

Fig 4. Hinging the tibial condyles to complete the osteotomy

The consistency of the bone in rheumatoid disease allows this
correction to take place and the removal of a wedge is never necessary.
In osteoarthritis the bone may not crush easily as in rheumatoid and nibbling the cortex enables the deformity to be corrected without a formal wedge excision.

Femoral osteotomy
The patella is redislocated and with the knee flexed bone levers are inserted on either side of the lower end of the femur. The femoral osteotomy site is at the widest part of the femoral condyles and is thus not merely within the knee joint but well distal to the most proximal portion of the articular cartilage. Care is taken that the osteotomy is at a right angle to the femoral shaft such that it remains entirely in the cancellous condylar bone and does not extend to the shaft proximally where non-union is possible.
The osteotomy is undertaken in a similar fashion (fig 5&6) to that of the tibia.

Fig 5. A narrow osteotome vertical through the lateral cortex
and meet it with a broad one from the medial side

Fig 6. Hinging the femoral condyles to complete the osteotomy

The cortex nibbling in hard osteoarthritic bone reduces the tendency of the femoral condyles to displace posteriorly when correction of deformity is taking place. Such displacement would reduce knee flexion range.

Any residual deformity that is uncorrected at the tibial osteotomy is corrected at the femur by manipulation; again with the knee straight.
The deformity should be overcorrected by a few degrees, as the joint always opens a little and apparent correction is due partly to ligamentous laxity. The tourniquet is released and the capsule approximated with a few interrupted sutures to hold the patellar mechanism in place.

As already stated in both tibia and femur, the removal of a wedge is unnecessary as angulation is easy to achieve, furthermore removal of bone causes unnecessary shortening and is more likely to lead to non-union.

Postoperative Regime
The limb is immobilised in a plaster of Paris cylinder. Any deformity is a shade overcorrected with the knee hyperextended by 2-3°. The correct alignment is checked with a long rod, placed, one end over the femoral pulse, that is, the hip joint, and the other over the centre of the ankle. The rod should overlie the centre of the knee.(Fig 6)

correct -- -----valgus ------- ----varus

Fig 6

Foot pulses are checked in theatre and radiographs taken.
On recovering from the anaesthetic, weight bearing is allowed immediately. At 6 weeks the patient is readmitted and the cylinder removed. Knee mobilisation is encouraged. After 48 hours if the knee is flexing less than 35°, manipulation under anaesthetic is performed holding the femur distally to protect the femoral osteotomy. Physiotherapy is generally unnecessary, it may cause undue pain and
is at times counterproductive. It is advisable to follow our procedure
accurately including the postoperative regime in order to reproduce our
results.

Post Operation X-rays

It is of the utmost importance to achieve the correct position in the plaster within two to three days of surgery. The valgus/varus deformity should be over-corrected by three to five degrees. The knee should be in three to five degrees of hyperextension.
Long x-ray films are adviseable perhaps including the ankle.

The knee double osteotomy is described in the book Surgical Repair and Reconstruction in Rheumatoid Disease
and the shoulder osteotomy in Operative Shoulder Surgery (see refs)

Recent Experience

Knee double osteotomies are being undertaken in several centres and it is hoped that information concerning these including outcome will appear on this website.