An osteotomy is a surgical procedure where the bone is cut to change its length or alignment. Often the procedure is done in an attempt to correct an abnormality that has resulted from trauma or disease.
The procedure is able to correct the following deformities.
- valgus/varus angulation
- anterior/posterior angulation
- internal/external rotation
- lengthening/shortening
- medial/lateral shift
- dorsal/ventral shift
An osteotomy corrects the biomechanical alignment of the extremity, increases the contact area or improves joint congruence and restores the biomechanical advantage.
Indications for Osteotomy
Growth Discrepancy
Growth disturbances may be caused by trauma, disease, or genetic predisposition, often due to the premature closure. This is especially a problem in forearm and legs where two bones are present. The unaffected bone continues to lengthen while the damaged bone lengthens at a slower rate, the normal bone will be forced to bow away from the shortened bone leading to deformity and altered joint orientation.
Osteotomy is necessary to straighten the deformity and return the limb to a normal function and appearance.
Similarly, trauma a portion of a growth plate may result in a selective slowing or cessation of growth on that side while growth is normal on the unaffected side of the same bone. For example, trauma to the lateral side of the distal radial physis results in valgus deformity if the wrist. Osteotomy through the site of maximal deformity is necessary to return the bone to the normal anatomical position.
Deformity following Malunion
Diaphyseal and metaphyseal fractures may unite in malposition resulting in angular, rotational, or shortened positions requiring osteotomy.
Rotational Deformities
These may occur following trauma or due to a congenital condition such as tibial torsion. Osteotomy may be necessary in severe cases affecting limb function.
Limb Length Discrepancy
In limb lengthening surgeries, osteotomy may be performed so as bone ends could be distracted by using hardware like Ilizarov external fixator.
Dysplasia Correction
For example in hip dysplasia. Usually performed early before setting in of arthritic changes.
Contraindications
- Neuropathic Arthropathy
- Inflammatory Arthropathy
- Active Infections
- Severe Osteopenia
- Advanced Arthritis
Principles
- Accurate alignment and reduction of the osteotomy gap must be accomplished
- Rigid fixation, using internal fixation or external fixation must be provided
- Soft tissues must be carefully protected
Planning of the Procedure
It is important to plan the procedure to minimize any chance for error.
Preoperative radiographs in at least two views should be taken of both the affected bone or bones and the normal unaffected contralateral limb. Radiographs must include the entire joint above and below the deformed bone. Rotational deformity can be missed on radiographs and should be measured clinically.
The correction should be planned at the site of greatest deformity.
Amount of bone resection, angle and plane of osteotomy should be well planned by preoperative drawings.
Types of Osteotomies
Transverse
It is ideal for correction rotation alone in the metaphyseal and diaphyseal region. The procedure is performed at the area of major rotation by cutting a transverse plane through the bone. When the transverse osteotomy technique is employed, the fixation is very stable.
Oblique
Oblique osteotomy allows two bones to be separate or lengthened and still allow for point contact. It can also be used to provide rotational correction as well by placing the proximal obliquity into the medullary cavity of the distal fragment, thus providing a pivotal point for derotation and varus or valgus realignment
Wedge Osteotomy
Also called cuneiform osteotomy, wedge osteotomy is used primarily to correct angular deformity, but may be used for angular and rotational problems if both exist simultaneously.
It is of following types
Open Wedge
The cut is made at the desired site and a bone wedge is inserted on the concave surface. It results in bone lengthening.
Closing Wedge Osteotomy
A predetermined size of the wedge of bone is removed from the point of maximal deformity with the base of the wedge is at the convex surface of the deformity. The gap is then closed, correcting the angulation and fixed. It results in slight bone shortening.
Fixation of Osteotomies
Osteotomies can be stabilized using all conventional forms of internal or external fixation.
It could be
Internal fixation – plating, screws, K-wire fixation, tension band wiring
External fixation – Tubular fixator, Ilizarov fixator
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