Abstract
Introduction: Instrumental Distraction has opened a new window for management of resistant clubfoot. Classical Ilizarov assembly is typically used in patients over the age of two years. We applied the differential distraction technique using the UMEX fixator for ages varying from 6 months to 18 years. This method follows the Ilizarov principle of soft tissue response to tension stress.
Materials and Methods: A retrospective review included 120 patients, treated between 1990 – 2001. The majority of the cases were “idiopathic” with 36 feet after failed surgery, 60 feet after failed manipulation and casting, and 11-neglected clubfeet. The non-idiopathic group included 5 feet in patients with arthrogryposis, 5 feet in patients with myelomeningocele, and 3 feet in patients with Streeter’s dysplasia. The UMEX frame spans three segments. The tibial segment consists of two wires trans-fixing the tibia in its proximal third and an axial pin to prevent rocking of the frame. The metatarsal segment incorporates a transfixing pin and two half pins to maintain the transverse arch of the foot. The calcaneal segment includes two transfixing wires and and an axial pin. The three segments are then linked together by a system of clamps, rods and distractors to create the UMEX clubfoot frame. Treatment extends through three stages: Reduction, Retention and Remodeling. The distractors apply differential distraction, and the various deformities are corrected simultaneously. After r eduction is completed the frame is left in a “holding” mode for six more weeks. Thereafter, the assembly is removed and a well-molded below-knee cast is applied for a period of 8 – 12 weeks with monthly cast changes. During the remodeling phase, night splints and walking boots are used for a period of one year.
Results: Results were assessed on the basis of the HJD functional rating system. Results were measured at 6-month intervals for 2 years and then yearly. We obtained excellent results in 34.4%; good, in 38.3%; fair, in 16.7% and poor, in 10.8% of the cases.
Discussion: The classical Ilizarov method of deformity correction is a constrained assembly applying distraction – compression forces across a predefined hinge. The unconstrined UMEX assembly makes no such demands and correction is achieved at the natural joints. The technique of differential distraction avoids any compression and, as seen in the long-term follow-up, has no ill effects on the growing foot. There is no age limit for use of the system; in older patients, however, incomplete remodeling leaves residual bone deformities. If there is residual foot deformity with completion of the treatment, only limited open surgery is required. In our hands, the use of differential distraction produced functionally serviceable and cosmetically acceptable correction of clubfoot.
Conclusion: Our experience demonstrates the effectiveness of differential distraction using the UMEX mini external fixator. This is an excellent technique for correction of complex deformities of the foot and ankle at any age and in the future may replace, to a large degree, the need for open clubfoot surgery.
Local Host: British Society for Children’s Orthopaedic Surgery. Conference Theme: Congenital Deficiencies of the Lower Limb. These abstracts were prepared by A.Catterall.
