The aim of this prospective single-centre study
was to assess the difference in clinical outcome between total knee replacement
(TKR) using computerised navigation and that of conventional TKR.
We hypothesised that navigation would give a better result at every
stage within the first five years. A total of 195 patients (195
knees) with a mean age of 70.0 years (39 to 89) were allocated alternately
into two treatment groups, which used either conventional instrumentation
(group A, 97 knees) or a navigation system (group B, 98 knees).
After five years, complete clinical scores were available for 121
patients (62%). A total of 18 patients were lost to follow-up. Compared
with conventional surgery, navigated TKR resulted in a better mean
Knee Society score (p = 0.008). The difference in mean Knee Society
scores over time between the two groups was not constant (p = 0.006),
which suggests that these groups differed in their response to surgery
with time. No significant difference in the frequency of malalignment
was seen between the two groups. In summary, computerised navigation resulted in a better functional
outcome at five years than conventional techniques. Given the similarity
in mechanical alignment between the two groups, rotational alignment
may prove to be a better method of identifying differences in clinical
outcome after navigated surgery.