Table 3.

Studies comparing N-THA vs. C-THA

Author	Study Type / Number of Patients	Study Group 1	Study Group 2	Outcome / Follow-up	Results
Jacob I et al., [13]	Case-Control study / 102 hips	N-THA	C-THA	Radiographs were evaluated for cup placement within safe zones (Lewinnek).	Cup inclination and anteversion were more consistent in N-THA group.
Naito Y et al., [14]	Case-Control study / 184 hips	N-THA	C-THA	CT scans were evaluated for cup placement within safe zones(Lewinnek). Complications were followed up.	Significantly higher percentage of acetabular cups were within safe zones using N-THA. But no difference was found in incidence of hip dislocation.
Tanino H et al., [37]	Prospective RCT / 110 hips	N-THA	C-THA	Radiographs were evaluated for cup placement within safe zones (Lewinnek).	Significantly higher percentage of acetabular cups were within safe zones using N-THA. But there was statistically significant increase in average operative time with N-THA.
Nishihara S et al., [38]	Case-Control study / 144 hips	N-THA	C-THA	CT scans were evaluated for cup placement within safe zones. Dislocations within 6 months of postoperative period were noted.	N-THA had less number of cases outside the targeted zone. One case in C-THA group developed posterior dislocation.
Takada R et al., [39]	Comparative study / 30 hips	Navigation assessment	Manual Goniometer Assessment	Evaluation using CT scan at 3 months for the absolute error in inclination and anteversion measured using navigation or goniometer intraoperatively.	Absolute estimate error of cup anteversion in navigation measurement was significantly lower than in goniometer measurement.
Okamoto M et al., [42]	Case-Control study / 221 hips	N-THA	Alignment Guide THA	CT scans were evaluated for cup placement within safe zones(Lewinnek). Functional outcome was evaluated.	Anteversion errors were less in N-THA group. No significant differences in functional outcomes was found.
Mihalic R et al., [40]	Prospective RCT / 84 hips	N-THA	C-THA	CT scans were evaluated for cup placement within safe zones(Lewinnek).	Less number of outliers from safe zone in N-THA group and significantly higher accuracy for anteversion was noted using N-THA.
Ogawa H et al., [16]	Prospective RCT / 41 hips	N-THA	C-THA	Radiographs and CT scans were evaluated for cup placement within safe zones (Lewinnek).	No significant differences were found in component placement using either methods.
Lass R et al., [41]	Prospective RCT / 110 hips	N-THA	C-THA	Radiographs were evaluated for cup placement at 6 weeks followup. Functional outcomes were evaluated for up to 2 years.	Significant difference in mean anteversion but no difference was noted in mean inclination. No difference in functional outcomes was found.