Malunion is defined as the healing of bone in an abnormal position which
with time can lead to problems and symptoms of a functional and/or cosmetic
nature.
Etiology
With just a few exceptions, fractures usually consolidate without any form of treatment. In the absence of skilled supervision of alignment during healing, muscle contraction leads to shortening so that by definition healing results in a nonanatomical position (malunion). In this situation shortening is unavoidable, lateral displacement can be expected, and axial abnormalities and rotational deviations are common. The spontaneous correction that occurs in children should not be expected in adults.
Clinical presentation
The patient soon notices a shortening of the lower extremity; and/or angulation in the frontal or sagittal plane. Rotational problems sometimes go unnoticed. Patients and their families particularly focus on the esthetic aspects of malunion; overloading and pain play a less prominent role. The indication for corrective osteotomy is mainly determined by the clinical consequences of malunion in the long term.
Diagnostics
X-ray examination: Standard x-rays (for intraarticular malunion also oblique views) are generally adequate. It is important to compare the affected side with the other side because a preexisting deformity, such as valgus or varus deformity of the legs or anteversion of the femoral neck, could be corrected by the fracture. Shortening and rotational abnormalities are measured clinically. The same applies to the range of motion of the adjoining joints which could compensate for an existing deformity.
Classification
According to localization:
Duration
An osteotomy heals within 6−8 weeks. Lengthening and/or callus distraction progresses at an average of 0.5−1 mm daily. Pseudarthroses can occur when lengthening procedures are used, while these complications are rare with other osteotomies.
Long-term disability often occurs as a result of malunion. Work can sometimes be resumed about 4 months after osteotomy, except after a lengthening procedure.
Prognosis
An osteotomy of a posttraumatic deformity that is optimally planned and performed technically correctly restores normal biomechanics and prevents secondary problems.
Etiology
With just a few exceptions, fractures usually consolidate without any form of treatment. In the absence of skilled supervision of alignment during healing, muscle contraction leads to shortening so that by definition healing results in a nonanatomical position (malunion). In this situation shortening is unavoidable, lateral displacement can be expected, and axial abnormalities and rotational deviations are common. The spontaneous correction that occurs in children should not be expected in adults.
Clinical presentation
The patient soon notices a shortening of the lower extremity; and/or angulation in the frontal or sagittal plane. Rotational problems sometimes go unnoticed. Patients and their families particularly focus on the esthetic aspects of malunion; overloading and pain play a less prominent role. The indication for corrective osteotomy is mainly determined by the clinical consequences of malunion in the long term.
Diagnostics
X-ray examination: Standard x-rays (for intraarticular malunion also oblique views) are generally adequate. It is important to compare the affected side with the other side because a preexisting deformity, such as valgus or varus deformity of the legs or anteversion of the femoral neck, could be corrected by the fracture. Shortening and rotational abnormalities are measured clinically. The same applies to the range of motion of the adjoining joints which could compensate for an existing deformity.
Classification
According to localization:
- Intraarticular
- Epiphyseal
- Metaphyseal
- Diaphyseal
According to malformation:
No treatment is necessary for a limb-length discrepancy of up to 2 cm, while shoe correction provides an adequate effect for a discrepancy up to 2.5 cm. If the discrepancy is more than 2.5 cm surgical treatment is indicated, tailored to the needs and wishes of the patient. If there are no axial abnormalities, shortening of the nonaffected limb by osteotomy is advisable because few complications occur with this treatment. Intertrochanteric shortening of the femur is associated with least complications. Bone lengthening using the Ilizarov method is an alternative. This treatment requires endurance from the patient and has a high complication rate especially in the femur.
Treatment of an intraarticular abnormality: The joint anatomy is restored by means of osteotomy and stable osteosynthesis, followed by functional follow- up treatment.
Treatment of an epiphyseal or metaphyseal abnormality: Correction of the deformity and fixation with a plate and screws or external fixation. An open- or closed-wedge technique can be chosen, depending on the difference in length, type of deformity, and presence of ligament instability.
Treatment of a diaphyseal abnormality: The mid point of the hip, knee, and ankle should form one straight line. Curves in between these points are not significant, as long as the knee and ankle are loaded horizontally. The correction of a diaphyseal abnormality is preferably performed at the level of the metaphysis because an osteotomy heals more rapidly at that location. Plates and screws are implants of choice for correction of metaphyseal and intraarticular malunions. Stable fixation and functional follow-up treatment after an osteotomy are more important than for the treatment of new fractures. Compression osteotomy with external fixation is possible if transfixation pins do not irritate the tendons and muscles too much, and the risk of joint infection is minimal (proximal and distal tibia). For corrections at the diaphyseal level, the medullary nail is the ideal implant.
- Shortening/lengthening
- Valgus/varus
- Antecurvatum/recurvatum
- Rotation
- Combinations
No treatment is necessary for a limb-length discrepancy of up to 2 cm, while shoe correction provides an adequate effect for a discrepancy up to 2.5 cm. If the discrepancy is more than 2.5 cm surgical treatment is indicated, tailored to the needs and wishes of the patient. If there are no axial abnormalities, shortening of the nonaffected limb by osteotomy is advisable because few complications occur with this treatment. Intertrochanteric shortening of the femur is associated with least complications. Bone lengthening using the Ilizarov method is an alternative. This treatment requires endurance from the patient and has a high complication rate especially in the femur.
Treatment of an intraarticular abnormality: The joint anatomy is restored by means of osteotomy and stable osteosynthesis, followed by functional follow- up treatment.
Treatment of an epiphyseal or metaphyseal abnormality: Correction of the deformity and fixation with a plate and screws or external fixation. An open- or closed-wedge technique can be chosen, depending on the difference in length, type of deformity, and presence of ligament instability.
Treatment of a diaphyseal abnormality: The mid point of the hip, knee, and ankle should form one straight line. Curves in between these points are not significant, as long as the knee and ankle are loaded horizontally. The correction of a diaphyseal abnormality is preferably performed at the level of the metaphysis because an osteotomy heals more rapidly at that location. Plates and screws are implants of choice for correction of metaphyseal and intraarticular malunions. Stable fixation and functional follow-up treatment after an osteotomy are more important than for the treatment of new fractures. Compression osteotomy with external fixation is possible if transfixation pins do not irritate the tendons and muscles too much, and the risk of joint infection is minimal (proximal and distal tibia). For corrections at the diaphyseal level, the medullary nail is the ideal implant.
Duration
An osteotomy heals within 6−8 weeks. Lengthening and/or callus distraction progresses at an average of 0.5−1 mm daily. Pseudarthroses can occur when lengthening procedures are used, while these complications are rare with other osteotomies.
Long-term disability often occurs as a result of malunion. Work can sometimes be resumed about 4 months after osteotomy, except after a lengthening procedure.
Prognosis
An osteotomy of a posttraumatic deformity that is optimally planned and performed technically correctly restores normal biomechanics and prevents secondary problems.
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