Objective To report a new offset parameter for total hip arthroplasty (THA)—greater trochanter offset (GTO), and analyze the effectiveness and feasibility of this parameter based on clinical data. Methods The 47 patients who met the selection criteria and admitted between January 2016 and May 2020 were selected as the research object. The global offset (GO) was used as the offset parameter in preoperative design. Firstly, the test-retest reliability and inter-rater reliability of GTO were analyzed based on pelvic X-ray films. The GTO reconstruction was defined as the difference between the operative side and the healthy side within ±5 mm, and 47 patients were divided into the reconstruction group and the non-reconstruction group. General data (age, gender, type and side of fracture, the interval between injury and operation), visual analogue scale (VAS) score, Harris score, gait score, and leg length discrepancy (LLD) were recorded and compared between two groups. Then, the GTO was used as the offset parameter in preoperative design of 21 patients (GTO group) admitted between June 2020 and December 2020. The pre- and post-operative clinical data were compared between GTO group and GO group to explore the feasibility of GTO for THA.Results Statistical analysis showed that GTO had good test-retest reliability (P<0.001) and inter-rater reliability (P<0.001). There was no significant difference in gender, age, type and side of fracture, the interval between injury and operation, preoperative VAS score, and LLD at 1 year after operation between the GTO reconstruction group and the non-reconstruction group, as well as between the GO and GTO groups (P>0.05). The Harris score and gait score at 1 year after operation, and difference of VAS score between pre- and post- operation in the reconstruction group and GTO group were significantly better than those in the non-reconstruction group and GO group, respectively (P<0.05). There were 23 cases (48.9%) in the GO group and 19 cases (90.5%) in the GTO group with GTO reconstruction, and the difference was significant (χ2=10.606, P=0.001). There were 25 cases (53.2%) in the GO group and 13 cases (61.9%) in the GTO group with GO reconstruction, and the difference was not significant (χ2=0.447, P=0.504). There were 34 cases (72.3%) in the GO group and 19 cases (90.5%) in the GTO group with LLD reconstruction, and the difference was not significant (χ2=2.777, P=0.096). Conclusion GTO has reliable test-retest reliability and inter-rater reliability. GTO as a parameter of preoperative offset reconstruction plan of THA can obtain good reconstruction of offset and limb length, and obtain a good effectiveness.
Objective To analyze the impact of robot assistance on the restoration of limb length and offset distance in total hip arthroplasty (THA). Methods A retrospective analysis was conducted on the clinical data of 316 patients who underwent unilateral primary THA between September 2019 and August 2023. Among them, 117 patients underwent robot-assisted THA (group A), and 199 patients underwent conventional THA (group B). There was no significant difference between the two groups in the gender, age, or side of the hip replacement (P>0.05); but there was a significant difference in the preoperative diagnosis (P<0.05). The leg length discrepancy (LLD) and global offset (GO) dfference were measured on preoperative anteroposterior pelvic X-ray films, and absolute values were used for comparison between groups. Results The operations in both groups were successfully completed. Postoperative imaging measurements showed that the LLD and GO dfference in group A were significantly lower than those in group B (P<0.05). Among them, group A had 32 cases (27.4%), 5 cases (4.3%), and 0 case (0) of LLD>3 mm, >5 mm, and >10 mm, respectively, while group B had 115 cases (57.8%), 75 cases (37.7%), and 22 cases (11.1%), respectively; and the differences in above indicators between groups were significant (P<0.05). Group A had 40 cases (34.2%), 3 cases (2.6%), and 0 case (0) of GO dfference>5 mm, >10 mm, and >20 mm, respectively; group B had 103 cases (51.8%), 54 cases (27.1%), and 7 cases (3.5%), respectively. There was no significant difference in the proportion of patients with GO>20 mm between groups (P>0.05), while there were significant differences in other indicators between groups (P<0.05). Conclusion Compared with traditional THA, robot assisted THA has more advantages in restoration of limb length and offset distance.