Acetabular Cup Placement in Navigated and Non-Navigated
Total Hip Arthroplasty (THA): Results of Two Consecutive
Series Using a Cementless Short Stem
Yingyong Suksathien MD*,
Rachawan Suksathien MD**, Porameth Chaiwirattana MD*
Affiliation :
* Department of Orthopedic Surgery, Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima, Thailand
** Department of Rehabilitation Medicine, Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima, Thailand
Background : Acetabular component malposition has been linked to increased rates of dislocation, impingement, pelvic
osteolysis, cup migration, leg length discrepancy, and polyethylene wear in patients undergoing total hip arthroplasty (THA).
Objective : Compare the acetabular component positioning and the operative time in two consecutive short-stem cementless
THA series without and with using an imageless navigation.
Material and Method: The retrospective study consisted of 31 cases of short-stem cementless THA without navigation
(NNAV) and 30 cases with navigation (NAV). CT scans were performed in all cases at two-month or later postoperatively.
The abduction and anteversion angles measured on postoperative CT were compared between two groups using t-test. The
percentage of cup placement (abduction, anteversion and combined) within the safe zone for each group was compared
using Chi-square test at a 0.05 level of significance. The operative time was compared between two groups using t-test.
Results : The mean abduction was 43.97 (range, 33-52, SD 4.44) in NNAV group and 41.37 (range, 37-45, SD 2.01) in NAV
group. This difference was significant (p = 0.004). The mean anteversion was 22.58 (range, 2-39, SD 10.68) in NNAV group
and 13.57 (range, 7-18, SD 3.28) in NAV group. This difference was significant (p<0.001). According to the criteria of
Lewinnek et al, 96.8% in NNAV group were placed within the safe zone for abduction, 51.6% for anteversion, and 48.4%
for both abduction and anteversion. In NAV group, all 30 cups (100%) were placed within the safe zone for abduction,
anteversion, and both. There were significant differences in the percentage of cup placement within the safe zone for
anteversion (p<0.001), for both abduction and anteversion (p<0.001) but not significant for abduction (p = 0.32) between
two groups. The mean operative time was 107.09 and 110.67 minutes for NNAV and NAV group respectively, this difference
was not significant (p = 0.49).
Conclusion : The present study demonstrated a significant increase in the placement of acetabular cups within the safe zone
using imageless navigation compared to freehand technique, especially at anteversion angle.
Keywords : Hip arthroplasty, Imageless navigation
All Articles
Download