There are a number of series comparing DAA hip arthroplasty with other approaches. Barrett et al¹⁰ reported a comparison series of randomized patients undergoing DAA or posterior approach hip arthroplasty and found that the DAA had better pain scores, better stairs, better walking at 6 weeks, and higher Hip Disability and Osteoarthritis Outcome Score at 3 months. Schweppe et al¹¹ compared the DAA with posterior approach hip arthroplasty with 100 patients in each group. The DAA group had less narcotic use, a shorter length of stay, fewer 30-day readmission rates, and better cup positioning.¹¹ Restrepo et al¹² reported a prospective randomized trial of DAA versus direct lateral approach hip arthroplasty and found improved Short Form-36 and Western Ontario and McMaster Universities Arthritis Index scores that persisted to the 1-year postoperative visit.

There are also several meta-analysis reports supporting enhanced recovery with the DAA. Wang et al¹³ performed a meta-analysis of nine randomized controlled trials comparing DAA with posterior approach hip arthroplasty and found an improved Harris Hip Score at 2 and 4 weeks; no significant differences were found at 12 weeks and 1 year. In addition, they reported lower visual analog pain scores at 24, 48, and 72 hours and a smaller incision with less blood loss. Another review of 17 studies totaling 2302 participants reported less pain and improved function at the short-term follow-up with a shorter length of stay and fewer dislocations.¹⁴ In a Cochrane review of 42 studies, Meermans et al¹⁵ reported better mean hip scores before 6 weeks, including the Harris Hip Score and the Western Ontario and McMaster Universities Arthritis Index. In another meta-analysis of 13 prospective studies, of which seven were randomized, the DAA was associated with less pain, fewer narcotics consumed, and better function through 90 days.¹⁶

Bergin et al¹⁷ reported creatine phosphokinase levels 5.5 times higher in patients with posterior approach hip arthroplasty. Serum markers including creatine phosphokinase, C-reactive protein, myoglobin, and interleukin 6 have also been reported to be lower in patients with DAA hip arthroplasty compared with the posterior approach. Those patients also walked 35 ft farther and had lower visual analog pain scores.¹⁸ Meneghini et al¹⁹ evaluated muscle damage in a cadaveric study and found more damage to the short external rotators, piriformis, and gluteus medius in the posterior approach specimens and more damage to the tensor fascia lata and rectus femoris in the anterior approach specimens. The piriformis and conjoined tendon were released 50% of the time for femoral access in the anterior approach specimens as well.¹⁹ Magnetic resonance imaging evaluating soft tissue damage demonstrated significantly less damage
to the gluteus medius in patients who underwent DAA approach hip arthroplasty compared with the direct lateral approach, but there was no difference in damage to the tensor fascia lata.²⁰ Another magnetic resonance imaging study comparing muscle damage in four hip approaches showed generally more muscle damage in the direct lateral and posterior approaches than in the anterior and anterolateral approaches.²¹ The posterior approach had more damage to the short external rotators and the direct lateral approach to the gluteus minimus.²¹

A gait analysis study compared direct anterior and anterolateral hip arthroplasty patients and found improved abductor strength in the direct anterior group at 6 weeks but no differences at 16 weeks.²² A 2-year follow-up gait study comparing the anterolateral approach and the DAA demonstrated no differences in chest and pelvic kinematics; however, there was a significant difference in cadence and stride time.²³ A clinical comparison study of the DAA versus the mini-posterior approach showed patients in the DAA group had a better single-leg stance, were more likely to not have Trendelenburg gait, and were able to single-cane walk at 3 weeks. Additionally, the acetabular cup position was in the safe zone 99% of the time in the anterior group compared with 91% of the time in the posterior group.²⁴