Open-wedge high tibial osteotomy: comparison between manual and computer-assisted techniques

The purpose of our study was to compare clinical and radiological results of two groups of patients treated for medial compartment osteoarthritis of the knee with either conventional or computer-assisted open-wedge high tibial osteotomy (HTO). Goals of surgical treatment were a correction of the mechanical axis between 2A degrees and 6A degrees of valgus and a modification of posterior tibial slope between -2A degrees and +2A degrees. Twenty-four patients (27 knees) affected by varus knee deformity and operated with HTO were prospectively followed-up. They were randomly divided in two groups, A (11 patients, conventional treatment) and B (13 patients, navigated treatment). The American Knee Society Score and the Modified Cincinnati Rating System Questionnaire were used for clinical assessment. All patients were radiologically evaluated with a comparative lower limb weight-bearing digital radiograph, a standard digital anteroposterior, a latero-lateral radiograph of the knee, and a Rosenberg view. Patients were followed-up at a mean of 39 months. Clinical evaluation showed no statistical difference (n.s.) between the two groups. Radiological results showed an 86% reproducibility in achieving a mechanical axis of 182A degrees-186A degrees in group B compared to a 23% in group A (p = 0.0392); furthermore, in group B, we achieved a modification of posterior tibial slope between -2A degrees and +2A degrees in 100% of patients, while in group A, this goal was achieved only in 24% of cases (p = 0.0021). High tibial osteotomy with navigator is more accurate and reproducible in the correction of the deformity compared to standard technique. Therapeutic study, Level II.