Dislocation and subluxation during femoral lengthening

Area of Science:

• Orthopedic Surgery
• Pediatric Orthopedics
• Limb Lengthening

Background:

• Femoral lengthening by callus distraction is a surgical technique used to correct leg length discrepancies.
• Hip joint stability is a critical consideration during limb lengthening procedures, particularly in pediatric patients.

Purpose of the Study:

• To evaluate the effect of femoral lengthening on hip joint stability, specifically femoral-head displacement, in pediatric patients.
• To identify preoperative factors that predict the risk of hip deterioration following femoral lengthening.

Main Methods:

• Retrospective analysis of 26 femoral lengthening procedures in 18 patients (ages 6-17) performed between 1988 and 1992.
• Assessment of femoral-head displacement using the change in the center-edge (CE) angle, with patients stratified by preoperative CE angle (< or = 20 degrees vs. > 20 degrees).

Main Results:

• None of the 14 hips with a preoperative CE angle > 20 degrees showed deterioration.
• Five of 12 hips with a preoperative CE angle < or = 20 degrees experienced deterioration, including one complete dislocation and four cases of decreased CE angle.
• Deterioration was more common in hips with a history of congenital hip dislocation or multiple epiphyseal dysplasia.

Conclusions:

• Femoral lengthening by callus distraction can lead to hip deterioration in patients with a preoperative center-edge angle of 20 degrees or less.
• Preoperative center-edge angle is a significant predictor of hip stability after femoral lengthening.
• Innominate osteotomy or other bony procedures should be considered before femoral elongation in patients with a preoperative CE angle of 20 degrees or less to mitigate risks.