ARE EXISTING CLASSIFICATIONS USEFUL IN RECONSTRUCTION OF CONGENITAL LONGITUDINAL LOWER LIMB DEFICIENCIES?

Abstract

Objective: To review the existing classifications in characterizing the pathological morphology of congenital lower limb deficiencies and their usefulness in planning limb reconstruction.

Methods: Ninety-five patients undergoing limb reconstruction were classified using existing classifications. Predominantly femoral deficiencies were classified using Aitken,Amstutz,Hamanishi,Gillespie andTorode,Fixsen and Lloyd-Roberts, Kalamchi, and Pappas systems and fibular deficiencies were classified using Coventry and Johnston, Achterman and Kalamchi, and Birch systems.

Results: All patients with predominantly femoral deficiencies also had associated shortening of ipsilateral tibia and fibula. Similarly, most patients with predominantly fibular deficiencies also had some associated shortening ipsilateral femur. Acetabular dysplasia, knee instability due to cruciate insufficiency and lateral femoral condylar hypoplasia were found in both femoral and fibular deficiencies. None of the existing classification systems were able to represent the complete pathologic morphology in any given patient. Due consideration of alignment, joint stability and length discrepancy of affected limb as a whole at the planning stage of reconstruction could not be ascertained using these classification systems. Instead, it was useful to characterize the morphology of the involved limb using the following method:

• Acetabulum: Dysplastic/ Non-dysplastic (AC index, Sharp’s angle, CE angle)

• Ball (Head of femur): Present/Absent

• Cervix (Neck of femur): Presence of pseudoarthrosis & neck-shaft angle

• Diaphysis of femur: Length / deformity

• Knee: Presence of cruciates, patellar and femoral con-dylar hypoplasia

• Fibula and Tibia: Presence/ absence, length and deformity

• Ankle: Normal/Ball and socket/ valgus

• Heel: Presence of tarsal coalition and deformity (valgus, equinus)

• Ray: Number of rays present in the foot

Conclusion: Congenital longitudinal lower limb deficiency is a spectrum of disorder involving the entire lower limb. Existing classifications do not represent the complete morphology of the entire involved lower limb and therefore a systematic method of characterizing the morphology of the lower limb is more useful in planning limb reconstruction.