Abstract
Introduction
Leg length and offset are important considerations in total hip arthroplasty (THA). Navigation systems are capable of providing intra-operative measurements, which help guide the surgeon in leg length and offset adjustment.
Objective
This controlled study investigates whether the use of computer navigation leads to more accurate achievement of pre-operative leg length and offset targets in THA.
Method
A total of 61 patients were included in the study. A prospective, consecutive series of 24 patients undergoing navigated total hip arthroplasty were compared to an historic, consecutive series of 37 patients who underwent total hip arthroplasty without the use of navigation. The changes made to leg length and femoral offset were measured from scaled pre- and post-operative digital radiographs. The target changes to leg length and femoral offset were recorded from pre-operative digital templating sessions.
Results
No statistically significant differences in terms of age, sex and body mass index were found between the two groups. Femoral offset targets were more closely achieved in the navigated cohort compared with the non-navigated group (P < 0.05). The mean deviation from the pre-operative target offset change was 2.9 ± 2.7 mm in the navigated group, and 5.1 ± 4.6 mm in the non-navigated group. For leg length, no statistically significant difference was found between the navigated and non-navigated cohorts in the difference between planned targets and radiographic changes (P=0.78). The mean deviation from target leg length change was 3.9 ± 2.9 mm in the navigated group and 4.2 ± 3.4 mm in the non-navigated group. When the navigation system was employed, procedure time was longer by a mean of 6 minutes, however this finding was not statistically significant (P=0.084).
Conclusion
The use of navigation helps the surgeon to achieve their pre-operative goals for offset change. The navigation system was not shown to impact leg length management.
