Untill recently, major reduction defects of the tibia were treated by amputation and prosthetic fitting. However, Wada et al (1) and Weber (2) recently reported impressive results of limb reconstruction in children with tibial aplasia. If an attempt is being made to reconstruct the leg and foot, a clear understanding of the nature of anomalies is necessary.

A retrospective study of case records and radiographs of children with congenital anomalies of the tibia seen at our centre was undertaken to determine the patterns of associated anomalies in the leg and foot. In addition, five amputated specimens of the leg and foot from children with complete tibial aplasia were dissected.

A wide spectrum of congenital anomalies of the tibia was seen and this included complete aplasia, partial aplasia, hypoplasia, dyplastic trapezoidal tibia and congenital bowing.

Complete and partial aplasia was seen either with or without duplication of the formed skeletal elements. The patterns of duplication that were seen included fibular dimelia, pre-axial mirror polydactyly, duplication of the calcaneum, cuboid and lateral cuneiforms. Trapezoidal dysplastic tibia was associated with duplication of the talus and pre-axial mirror polydactyly.

Dissection of the amputated specimens of complete tibial aplasia revealed aplasia of some muscles, aberratant tendinous structures, abnormal insertion of muscles and absence of the plantar arterial arch.

An understanding the nature of these associated anomalies in children with tibial aplasia and dyplasia will help the surgeon to decide the strategies for reconstruction of the limb if that is the desired option.

At the other end of the spectrum of congenital anomalies of the tibia is posteromedial bowing which was considered an innocuous condition that required little or no treatment. A review of 20 cases of posteromedial bowing demonstrated that there are number of problems related to the leg, ankle and foot that may require surgical intervention.

The foot and ankle are very commonly affected in various paralytic conditions. Paralysis of different muscles acting on the foot results in characteristic gait aberrations. The gait abnormalities are a result of one or more of the consequences of paralysis including: loss of function, muscle imbalance, deformity and instability of joints.

The aims of treatment of the paralysed foot and ankle are to: make the foot plantigrade, restore active dorsiflexion during the swing phase of gait (if this is not possible then prevent the foot from ‘dropping’ into plantar flexion during swing), ensure that the ankle and subtalar joints are stable throughout the stance phase of gait, facilitate a powerful push-off at the terminal part of the stance phase (if this is not possible, at least prevent a calcaneal hitch in terminal stance).

The specific aims of treatment in each patient depend on the pattern and the severity of paralysis that is present and hence the aims are likely to vary. In order to determine what treatment options are available in a particular patient, it is imperative that a careful clinical assessment of the foot is done. Based on the clinical assessment, these questions need to be answered before planning treatment: What are the muscles that are paralysed What is the power of each muscle that is functioning? Is there muscle imbalance at the ankle, subtalar or midtarsal joints that has either already produced a deformity or has the potential to produce a deformity in future? Are there any muscles of grade V power that can be spared for a tendon transfer without producing a fresh imbalance or instability

To facilitate responses to these questions, the muscle power of each muscle can be charted on a template that facilitates graphic representation of the muscle balance around the axes of the ankle and subtalar joints. This assessment clarifies whether a tendon transfer is a feasible option. If a tendon transfer is considered feasible, then the following questions also need to be answered: Is there a fixed, static deformity that needs to be corrected prior to a tendon transfer? If a tendon transfer was performed, would the child be capable of comprehending and cooperating with the post-operative muscle re-education programme?

The decision-making process will be outlined and the use of the template in choosing the tendon transfer and deciding the site of anchorage of the transferred tendon will be explained. With suitable examples the choice of tendon transfers in different patterns of paralysis would be illustrated.