Abstract
The arthritic varus knee (AVK), charaterised by an overloaded medial compartment of the joint, shows different clinical patterns with corresponding distinctive pathological signs. The surgical approach with opening wedge high tibial osteotomy is indicated in less demanding cases. Transferring the stress in the cartilage and bone of lateral compartment it may represent a definitive solution for both the deformity and the mechanical axis.
Between 1995 and 2003 we treated 52 patients, 60 knees, with distractional osteogenesis using external fixators. The mean age was 51 years (range 45 to 68 years). Radiographic findings showed a third-degree condition according to the Ahlback classification, while pathologically the condition was considered second degree according to the Outerbridge classification. The mean initial varus angle was 8.2°. We analysed the clinical results using the Hospital for Special Surgery score scale and the radiographic result by standing standard X-rays and Rosemberg X-rays.
We followed 38 of 52 patients for 3, 6, 9 and 12 months and then conducted a yearly control with a mean follow up of 4.2 years. The clinical score was 78.5 versus 45.5 in the pre-operative evaluation. At the follow-up radiographic evaluation shows a valgus angle of 2.98° even if there was less of initial correction (mean angle at 6 month 3.53°).
The technique used, moving the weight to the normal compartment of the knee, gives a definitive solution to varus of the femoral-tibial joint, correcting both the deformity and the mechanical axis. The treatment showed several advantages for possible new correction in the late post-operative period and and a minimally invasive operation, even though patient compliance is not good. The best results were obtained thanks to rigorously following the indication for this treatment. In these patients we consider distractional osteogenesis using external fixators a definitive treatment for AVK and not only a way to gain time and to postpone total knee replacement, which is always possible after an osteotomy.
