Comparison Of Clinical Outcomes,Radiological Outcomes And Bone Remodeling Outcomes Between Proximal Coated Single-Wedge New Stem And Full Coated Dual-Wedge Classic Stem In 1-Stage Bilateral Total Hip Arthroplasty

Objective: This retrospective study investigated the clinical outcomes,radiological outcomes,and bone remodeling patterns associated with a Medial/Lateral Taper(M/L Taper)stem and Link Classic Uncemented(LCU)stem in 1-stage bilateral total hip arthroplasty(THA).Methods: The results of 52 patients who underwent 1-stage bilateral THA with a M/L Taper stem on one side and an LCU stem on the other between January 2012 and February 2015 were retrospectively compared.Patients were clinically assessed by the Harris hip score(HHS),visual analogue score(VAS)and incidence of complications.Radiological indicators,such as neck-shaft angle,offset,vertical height of the rotational centre and Engh score,were measured on X-ray examinations.Periprosthetic bone remodelling was assessed via bone mineral density(BMD)measurements.Results:1.The mean follow-up time was 5.2 years.At each follow-up,there was no difference in the HHS and VAS between the 2 groups.2.The complication incidence rates were 6/52(11.54%)in the M/L Taper group and 10/52(19.23%)in the LCU group,with no significant difference(statistic=0.643,P=0.424).3.The neck-shaft angle(130.79 °± 3.42 ° vs 133.50 °± 2.91 °,t=5.344,P < 0.001),offset(41.95 mm ± 5.71 mm vs 46.40 mm ± 4.75 mm,t=4.293,P< 0.001),vertical height of the rotational centre(63.24 mm ±4.73 mm vs 67.54mm±5.76 mm,t=4.672,P<0.001)and limb lengthening(2.97 mm ± 7.23 mm vs 8.79 mm ± 7.75 mm,t=4.359,P < 0.001)were significantly lower in the M/L Taper group than in the LCU group.4.The Engh total score was 25.31±2.72 in the LCU group and 26.24±1.72 in the M/L Taper group,with a significant difference(t=2.116,P=0.039).5.Significantly higher(P<0.001)BMDs were observed in the M/L Taper group than in the LCU group in Gruen zones 1,2,and 6.In contrast,significantly lower(P<0.001)BMDs were observed in the M/L Taper group than in the LCU group in Gruen zones 3 and 5.Conclusions:1.No differences in the clinical outcomes between the two groups were identified.2.Due to the increased postoperative neck-shaft angle,the LCU stem was prone to cause lower limb lengthening.The M/L Taper stem patients were more likely to have an insufficient postoperative neck length than the LCU patients.3.Regarding bone remodelling,the M/L Taper stem achieved proximal fixation and load transfer,leading to better preservation of the proximal femur,and was more in line with human biomechanical characteristics.