Minimally Invasive Anterolateral Approach Versus Modified Hardinge Approach In Total Hip Arthroplasty

Background: Total hip arthroplasty(THA)using the minimally invasive anterolateral approach(OCM)is generally considered to provide better and faster postoperative rehabilitation than the conventional hip approach.However,in clinical practice,the correctness of this conclusion is still controversial.To our knowledge,in THA,few prospective randomized studies have compared the mid-term outcomes of minimally invasive anterolateral approach and conventional approach.The purpose of this study was to compare the results of the minimally invasive anterolateral approach(OCM group)with the modified Hardinge approach(MH group)in mid-term(1-year)follow-up.Methods: From October 2019 to January 2021,patients who underwent total hip arthroplasty in our hospital were included and operated by the same senior expert,including 38 patients who underwent minimally invasive anterolateral approach(OCM group)and 39 patients who underwent modified Hardinge approach(MH group).All patients received cementless acetabular cups and femoral prostheses with the same design and used the same anesthetic regimen.The demographic characteristics and preoperative diagnosis of the two groups were matched.The visual analogue scale(VAS)was used to evaluate the pain before surgery,at rest and during activity after surgery,and the EQ-5D index(Euro Qol Five Dimensions Questionnaire)was used to evaluate the quality of life of the patients.Harris hip score(Harris Hip Score,HHS),time up and go test(TUG),and10-meter walk test(10m WT)were used to assess hip function.The above subjects were evaluated on postoperative day 2,6 weeks,and 1 year,respectively.Radiographic evaluation included femoral stem alignment(FSA),cup abduction angle(CABA),cup anteversion angle(CANA)and leg length discrepancy(LLD).Results: Patients in the OCM group had less pain on the second postoperative day(VAS41 in the OCM group and VAS 56 in the MH group).The TUG score on day 3 was 5seconds faster in the OCM group than in the MH group.The HHS score in the OCM group was 7,which was higher than that in the MH group.At 6 weeks,the EQ-5D index(OCM 0.86,MH 0.79)was also higher in the OCM group.All differences were statistically significant.At 1-year follow-up,no significant differences in pain scales,quality of life,or hip function scores were observed between the OCM MH groups.Three complications related to the surgical approach occurred in the OCM group(mainly in terms of skin incisions),whereas no complications occurred in the MH group.The mean values of CABA,CANA,stem valgus and LLD for the OCM group were within the acceptable ranges.The incidence of varus stem alignment(> 5)was significantly higher in the OCM group than in the MH group.Other complications such as infection,dislocation,fracture,claudication,and abduction weakness occurred in both groups.Conclusions: Our results suggest that the minimally invasive anterolateral approach and the modified Hardinge approach are effective and safe approaches for total hip arthroplasty.In the early postoperative follow-up,the use of minimally invasive methods helps to reduce pain,obtain better joint function as well as higher quality of life.However,significant advantages were observed in the long-term follow-up.Moreover,the incidence of skin-related complications in minimally invasive surgery is a disadvantage of this technique.In cases of obese patients and those with thigh muscularity,we recommend the use of a modified Hardinge approach rather than a minimally invasive anterolateral approach to prevent the occurrence of stem malalignment and leg length inequality.For surgeons,especially those within the learning curve,the possibility of varus stem development must be taken into account when choosing a minimally invasive anterolateral approach for total hip arthroplasty.