Purpose of the study: Despite the help provided for positioning the implants for total knee arthroplasty (TKA), the clinical pertinence of navigation remains a subject of debate. The purpose of this study was to analyse the clinical and radiological outcomes of TKA implanted with and without navigation and to assess the morbidity related to use of the system.

Material and methods: This was a prospective comparative study including 105 patients, mean age 71.5 years divided into two groups: navigated TKA (n=55) and non-navigated TKA (n=50). The same surgeon performed all operations using the same type of implant. We assessed perioperative variables. Clinical and radiological data were analysed pre-operatively then postoperatively with a prospective protocol (2.6 and 12 months) by a single observe. The statistical analysis accepted p< 0.05 as statistically significant.

Results: The two groups were comparable preoperatively regarding age, gender, BMI. Patients in the navigated group had significantly greater persistent flexion (5.32 versus 4.15, p=0.04) and valgus (4.19 versus 3.98, p=0.04) preoperatively. Operative time was measurably but not significantly longer with navigation (90.4 min versus 95.9 min), and was associated with greater blood loss (p=0.02). Intra- and postoperative complications and duration of the hospital stay were similar in the two groups (p> 0.05). The position of the implants was comparable in the two groups (HKA=179±1.58 in the navigation group and 176±3.6 in the non navigation group) with a smaller spread in angle values. At six months, active flexion was significantly better in the non-navigated group (107° versus 101°, p=0.016), but there was no difference in terms of patient satisfaction.

Discussion: Our study was unable to demonstrated any evidence of significant difference between TKA implanted with or without a navigation system. While the navigation system facilitates implant positioning and improves the reproducibility of the operative procedure, the difference is not significant in the hands of an experienced surgeon. Conversely, use of the navigation system, at least during the learning curve, has been associated with longer operative time and greater blood loss. For major deformities however, the navigation technique facilitates reconstruction of the knee joint.