Total Hip Arthroplaty (THA) using posterior approach(PA) that resect muscle have done from September, 2005 to August, 2006, but, for the purpose of a lower invasive surgery, we changed to THA using direct anterior approach(DAA) that preserve muscle from September, 2006. The purpose of this study was to compare the inflammation degree and clinical results of MIS-THA using PA with that of MIS-THA using DAA.

From September 2005 to May 2008,73 hips in 69 patients were treated with consecutive primary cement-less MIS THA. The breakdown of the patients was DAA, 51 hips, and PA, 22. The average age at operation was 66 years and 58 years. The average followup after primary THA was 1.5 years and 2.8 years. The sex ratio (M/F) was DAA 2/44, and PL 6/15. For the inflammation degree, CRP at the seventh day and 14 day after surgery of DAA was significantly lower than those of PA (p< 0.01). WBC of the seventh day of DAA was significantly lower than that of PA.CPK on DAA at the first was significantly lower than that of PL (p< 0.01), and CPK of PL took time for a long time to decrease to the level before the operation compared with DAA. For clinical results, there were no significant difference operative time, blood loss volume and complication in DAA and PA. No significant differences in the HHS at the final follow up were observed between DAA and PA. In the radiographic assessment, there was no significant difference in neutral position of stem of DAA(46hips) and PA (18hips), and there was no significant difference in abduction angle of socket in DAA(average 45°) and PA (47°). The day of SLR possibility was significantly earlier DAA (average 4 day) than PA (7). No significant differences in hospital stay were observed between DAA (average 21 days) and PA (26).

In the current study, there was thought that DAA was lower inflammation degree than PA, because normalization of CRP after surgery in DAA was significantly early in comparison with PA, and CPK of the first day after surgery was significantly lower in DAA than in PA. In the clinical assessment, the day of SLR possibility only was significantly earlier in DAA than in PA. This may imply muscle recovery of DAA is more rapid than that of PA. In the future, DAA will help to the further early rehabilitation and the early hospital discharge.