Direct anterior versus miniposterior THA with the same advanced perioperative protocols: surprising early clinical results.

BACKGROUND: Although some surgeons strongly advocate for one approach over the other, there are few data directly comparing the direct anterior approach with a miniposterior approach for total hip arthroplasty (THA). QUESTIONS/PURPOSES: Using the same advanced pain and rapid rehabilitation protocols for both groups, we compared the direct anterior and miniposterior approaches with respect to (1) return to activities of daily living at 2 days, 2 weeks, or 2 months; (2) risk of intraoperative or early postoperative complications; and (3) component position.
METHODS: Over a 1-year period we identified all consecutive, primary direct anterior and miniposterior THAs performed by two surgeons at our institution, totaling 242 patients. Of those, 20 did not meet inclusion criteria as a result of prior trauma or surgery about the hip. A total of 222 patients, 126 direct anterior and 96 miniposterior, were retrospectively evaluated. All cases were done by one of two surgeons, one of whom performs THA exclusively through the direct anterior approach and the other who only uses the miniposterior approach. Groups did not differ demographically with mean±SD age 64±12 years, mean body mass index 30±5.7 kg/m2, and 50% female. The same rapid rehabilitation protocols were used with no postoperative hip positioning precautions.
RESULTS: No differences were seen between the two groups in mean length of stay (2.2 days; range, 1-9 days), operative or in-hospital complications, intravenous breakthrough analgesia, stairs, maximum feet walked in-hospital, or percent discharged to home (80% [177 of 222]; all p>0.2). The direct anterior patients had longer mean operative times (114 minutes; range, 60-251 minutes) than the miniposterior patients (mean, 60 minutes; range, 41-113 minutes; p<0.001). The direct anterior group had a higher maximum visual analog scale pain score (5.3 direct anterior; ±2, versus 3.8 MP; ±2; p<0.0001). At 2 weeks, more direct anterior patients required gait aids (92% [116 of 126]) than miniposterior (68% [62 of 96]; p<0.0001). At 8 weeks, direct anterior patients had higher mean Harris hip scores (95 versus 89) but a lower return to work and driving with no difference in their use of gait aids, narcotics, activities of daily living, or walking 0.5 mile. More wound problems occurred in the miniposterior group (p<0.01). With the numbers available, component alignment was not different between the study groups (p>0.05 for all comparisons).
CONCLUSIONS: There was no systematic advantage of direct anterior THA versus miniposterior THA. Contrary to conventional belief and somewhat surprising were the fewer minor wound problems in the direct anterior group and the higher proportion of patients free of gait aids at 2 weeks and back to driving and working at 8 weeks in the miniposterior group. Factors other than surgical approach, perhaps including attentive pain management, patient selection, surgical volume and experience, careful preoperative templating, and rapid rehabilitation protocols, may be more important in terms of influencing early recovery after THA. LEVEL OF EVIDENCE: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.