Leg length discrepancy (LLD) is an infrequent diagnosis, most commonly occurring congenitally in children and rarely in traumatic incidents in adults. Circumferential external fixators are considered the optimal treatment method, but can be very costly and are not always readily available in less developed nations. The unilateral external fixator predates the circumferential but is more easily available and accessible worldwide and less expensive. This study sought primarily to characterize treatment outcomes using a unilateral external fixator where more advanced forms of treatment for LLD are not available. Secondary objectives included the site of the discrepancy and comparison of aetiologies.

Data were retrospectively reviewed from January 2010 to December 2017 on patients undergoing unilateral external fixation at our institution. Nineteen patients met the criteria, 14 with congenital LLD and five with lower leg bone loss from trauma.

There were 19 cases of LLD overall, with 14 cases on the tibia and 5 on the femur. Three of the five femur cases occurred in the trauma subgroup. There were 15 cases of congenital LLD and five cases of traumatic LLD. The mean overall LLD was 3.9 cm (2.3-5.2). The mean follow-up until healing for the entire cohort was 10 months (5-22).

We conclude that bone lengthening utilizing the unilateral external fixator is a good method and is cost-effective for bone lengthening where more advanced techniques are not available or cost-prohibitive. It is simple, and patients and families can collaborate with the surgeon to get a good final result. Patients are generally satisfied and can ambulate well after healing. In a resource-limited environment with cost as a barrier, if used correctly and judiciously, the unilateral external fixator can yield good results.