Bifocal Tibial Corrective Osteotomy With Lengthening in Achondroplasia

Abstract

The results and complications of bifocal tibial osteotomies with gradual correction and lengthening by Ilizarov ring fixator performed in 47 tibiae in 24 achondroplastic patients were analyzed. Comparison was made between the parameters of angular and torsional deformities of the tibia preoperatively, at fixator removal, and at last follow-up. Of these parameters, statistically significant change was seen postoperatively in the values of medial proximal tibial angle, lateral distal tibial angle, mechanical axis deviation, and tibial torsion, which changed from 78.8 +/- 7.05 degrees, 103.2 +/- 11.8 degrees, 25.1 +/- 14.6 mm (medial), and 22.7 +/- 10 degrees (internal) preoperatively to 87.3 +/- 6.3 degrees, 90.9 +/- 5.4 degrees, 5.3 +/- 10 cm (medial), and 15.8 +/- 4.2 degrees (external), respectively, at the time of fixator removal; and this correction was maintained during the follow-up period. Mean total tibial lengthening was 6.84 +/- 1.3 cm. Average healing index was 26.06 days/cm. Complications observed were 15 pin tract infections, 1 residual varus, 1 overcorrection into valgus, 2 recurrence of varus, 22 equinus contractures, 2 premature consolidations, and 3 fibula malalignments. Recurrence of varus was observed in limbs with a residual abnormal medial mechanical axis deviation due to femoral deformity. A hundred percent incidence of equinus was observed in limbs with tibial lengthening of more than 40%, with distal tibial lengthening of more than 15%. To minimize the risk for occurrence of equinus, we recommend restriction of distal tibial lengthening in achondroplasia to less than 15%, although total tibial lengthening may exceed 40%. Fibula malalignment was not observed after double fibula osteotomy. This procedure is safe and efficacious if performed with strict adherence to prescribed technique.

Is Bilateral Lower Limb Lengthening Appropriate for Achondroplasia?: Midterm Analysis of the Complications and Quality of Life

“…Achondroplasia is the most frequently encountered form of nonlethal skeletal dysplasia [4] and is characterized by defective enchondral ossification owing to defective gene encoding for fibroblast growth factor receptor 3 [6,14,20]. It is a type of rhizomelic dwarfism with an incidence of approximately one in 10,000 live births [6].…”

“…Limb lengthening by the Ilizarov method has been used in patients with achondroplasia by many authors during the past few decades, but with varying amounts of success [2,3,6,8,13,16,18,20]. Cattaneo et al [6] reported a considerable increase in length (14-18 cm) without major risk.…”

How Reliable Are Standard Radiographic Measures of the Foot and Ankle in Children With Achondroplasia?

“…Usually, the condition requires realignment surgery with a goal of limb alignment correction or limb lengthening [11,18,20]. The hip and knee alignment in achondroplastic children has been analyzed by Inan et al [7,8]; however, the foot and ankle alignment in achondroplastic children is less well understood and easy to be overlooked [5].…”

“…These measurements are important in evaluating the hindfoot, midfoot, and forefoot deformities. Surgical planning should focus not only on the lower limb alignment [11,20], but also on the complex deformities of the foot and ankle. Further research will apply these radiographic measurements to a series of affected feet in patients who have undergone operations for axial deviations to confirm whether these measurement methods of ''virgin'' feet are equally valid in postoperative patients with ACH.…”

“…Lower extremity radiographs including weightbearing radiographs of the feet and ankles are crucial for preoperative planning [5,7,8,20], but the reliability of radiographic measures in this patient population is unclear [5], and differences between the ACH population and children without ACH remain poorly characterized.…”