gms | German Medical Science

Objectives: Tibial hemimelia is a rare congenital disease with hypoplasia or agenesia of the tibia. In patients with complete tibial aplasia, treatment is controversial. Through-knee amputation used to be the gold standard, but with improved surgical methods, various reconstructive treatment options established. The aim is to create a knee joint which enables the patient to walk independently. Due to the complexity of the deformity, reconstructive treatment ought to be staged.The present study aimed to evaluate the role of femoro-pedal traction through external fixation as a way to prepare the affected limb for reconstructive surgery in patients with complete tibial aplasia. The purpose of traction is to distalize the fibula underneath the femur and to achieve sufficient soft tissue traction.

Methods: We conducted a retrospective study in 8 patients (9 limbs) with complete tibial agenesia who received a staged reconstructive treatment. During the first surgery a circular hexapod external fixator (Taylor Spatial Frame) was installed to achieve femoro-pedal traction. In the subsequent surgery we performed the reconstruction of the knee joint (patello-fibular chondrodesis in Jones 1a resp. chondrodesis of fibula and tibial anlage in Jones 1b), as well as a foot realignment.

Results and conclusion: The patients' mean age at fixator application was 2.81 (±1.18) years. Mean time under traction was 132.13 (±32.23) days. In all cases we achieved a sufficient distalization of the fibula by an average 40.56 (±12.48) mm. Pin infections occurred in 4 out of 9 cases (44,44%) and were successfuly treated with oral antibiotics. In one case the infection resulted in an osteomyelitis, demanding the replacement of the affected pin. In another case a femoral fracture occurred under traction, requiring surgical intervention. In none of our cases it was necessary to remove the frame prematurely. In all patients, ultimately a sufficient realignment of the leg as well as soft tissue traction, esp. in regard of the quadriceps muscle, was achieved, thus allowing reconstructive surgery to create a neoarthros.

In patients with tibial aplasia receiving reconstructive treatment, femoro-pedal traction is an efficient way to realign the leg and gain soft tissue traction in preparation of reconstructive surgery. On the downside, complications like pin site infections are frequent, but can usually be handled conservatively. Parents must be aware of the complexity of treatment, and good compliance is essential. In general, another 2 - 3 surgeries are required until achieving skeletal maturity, as knee extension decreases during growth. Procedures for limb lengthening can be performed subsequently.