Objective:To compare the clinical effects of direct anterior approach (DAA) and posterolateral piriformis-sparing approach (Mis-PLA) for minimally invasive surgery of total hip arthroplasty.Methods: The patients who had total hip arthroplasty from March 2015 to February 2016 were randomly divided into 2 groups: DAA group and Mis-PLA group.In the study,43 patients (45 hips) were performed with total hip replacement via the direct anterior approach (DAA group).As comparison,39 patients (42 hips) were performed with total hip replacement via the posterolateral piriformis-sparing approach (Mis-PLAgroup) at the same period.DAA group:27 male patients (27 hips),and 16 female patients (18 hips),with an average age of (57.4±7.3) years,preoperative Harris score (41.4±8.7),body mass index(BMI)(24.3±2.2) kg/m2;Mis-PLA group: 25 male patients (26 hips),14 female patients (16 hips),with an average age of (59.2±7.3) years,preoperative Harris score (39.6±8.4),BMI (24.7±2.5) kg/m2.The length of incision,operation time,blood loss,postoperative Harris score were observed and specially the hip functional recovery was fully assessed.Results: (1) All the incisions healed by first intention.No complications were found in both groups.The length of incision:DAA group:(9.2±0.7) cm and Mis-PLA group:(9.5±0.6) cm.No statistical significant differences were found (P=0.053).The operation time:DAA group (74.3±10.1) min and Mis-PLA group(37.5±4.3) min,which showed statistically significant differences(P<0.01).Blood loss:DAA group(229.6±79.2) mL and Mis-PLA group (215.7±56.0) mL.Nostatistical significant differences were found (P=0.366).(2) The patients in both groups were followed up for 6-12 months.The Harris hip scores for 6 weeks' follow-up:(85.5±4.1) in DAA group and (79.0±4.4) in Mis-PLA group,which indicated statistically significant differences (P<0.01).The Harris scores for the 6-month follow-up:(94.3±2.7) in DAA group and (95.2±1.9) in Mis-PLA group.No statistically significant differences were found (P=0.125).The basic daily hip function analysis for the 6-week follow-up:walking speed: no statistically significant differences were found between the two groups(P=0.298);Climbing stairs: Mis-PLA group' outcome was better than DAA group's with statistical differences (P=0.047);Circling,sitting and wearing shoes and socks: outcomes in DAA group exceeded Mis-PLA group's with statistically significant differences (P<0.01,P=0.016,P<0.01).Conclusion: Total hip arthroplasty through either DAA or Mis-PLA approaches could result in very satisfactory clinical effect.Comparing with DAA,Mis-PLA requires less operation time,shorter learning curve,which indicates that it is a re-latively safer approach.The advantages of total hip arthroplasty through direct anterior approach lie in less positional limitation in the early stage of postoperative period,as well as a faster recovery of hip function.

Objective:To compare the early efficacy of direct anterior approach versus posterolateral approach for total hip arthroplasty in elderly patients.Methods:The 48 elderly patients receiving total hip arthroplasty from September 2017 to September 2019 were divided into two groups: DAA group(n=23, 30 hips)receiving direct anterior approach for total hip arthroplasty, and PLA group(n=25, 33 hips)receiving posterolateral approach for total hip arthroplasty in this retrospective study.The operation time, blood loss, length of hospital stay, acetabular abduction angle, anteversion angle, and intraoperative and postoperative complications were recorded and compared between the two groups.The hip function was compared with Visual Analogue Scale(VAS)and Harris Hip Score(HHS).Results:All the 48 patients were followed up for 7-31 months, with an average of 22.8 months in DAA group, and 24 months in PLA group.The operation time was less in PLA group than in DAA group[(49.3±5.7)min vs.(70.3±6.2)min, t=12.22, P=0.00], while the hospital stay was longer in PLA group than in DAA group, with a statistically significant difference[(7.8±1.5)d vs.(5.6±1.3)d, t=-5.40, P=0.00]. There was no significant difference in intraoperative blood loss between the two groups[(173.1±47.9)ml vs.(189.6±48.7)ml, t=1.18, P=0.24]. The VAS and HHS scores were better at 1 month after operation and at the last follow-up than before operation in both DAA and PLA group(all P<0.05). The VAS and HHS scores were better in DAA than in PLA groups( P<0.05)at 1 month after surgery.However, at the last follow-up, there was no significant difference in VAS and HHS scores between the two groups( P>0.05). Conclusions:The early results of direct anterior approach for total hip arthroplasty are satisfactory in patients aged 85 years and older.It has the advantages of less trauma, faster postoperative recovery and shorter hospital stay.