| disease | Congenital Tibial Deficiency |
Congenital tibial deficiency is a rare longitudinal limb defect, often accompanied by various deformities such as proximal femoral dysplasia, femoral duplication, and tarsal coalition on the same side.
bubble_chart Clinical Manifestations
Kalamchi et al. classified it into three types based on clinical and radiographic findings. Type I is characterized by complete absence of the tibia, presenting with shortening and bowing of the lower leg; occasionally, absence of the medial metatarsal bones, knee flexion contracture, proximal migration of the fibular head, and distal femoral dysplasia may occur. Type II involves absence of the distal half of the tibia, with relatively well-developed proximal tibia and distal femur, thus preserving knee function. However, proximal posterior displacement of the fibula and grade I knee flexion contracture are present. Type III exhibits only distal tibial dysplasia, featuring distal tibiofibular joint separation, foot varus, and prominence of the lateral malleolus.
bubble_chart Treatment Measures
The deformity is complex, and treatment is also very difficult. The treatment method is usually selected based on the type of tibial deficiency and whether it is unilateral or bilateral. For unilateral type I tibial deficiency with distal femoral dysplasia, knee disarticulation should be performed at 2-3 years of age, followed by prosthetic fitting. For bilateral type I tibial deficiency, the Brown femoral-fibular plasty should be chosen to reconstruct knee joint function. The intermediate stage [second stage] involves performing ankle arthroplasty; the distal fibula is embedded into the pre-made groove on the talar articular surface and fixed longitudinally with Kirschner wires and gypsum external fixation.
For type III lesions, calcaneofibular fusion is recommended to stabilize the hindfoot and improve foot function.
The X-ray findings of this disease are characteristic, showing the absence of the tibia at different locations, making it relatively easy to reach a correct diagnosis. However, for cases with distal tibial absence, differentiation from congenital equinovarus is necessary during infancy.
