Direct Anterior Approach (DAA) is known to cause damage to the TFL during the surgical approach, the point of this study is to evaluate the impact between the severity of the per operative TFL damage and the functional short term results.

Total hip arthroplasty is one of the most frequent surgical procedure and it has changed the approach of hip arthrosis. There are a few surgical approaches frequently used : posterolateral approach, anterolateral approach and the direct anterior approach. It has been previously shown that the DAA is causing less muscle damage than the other surgical approaches, the anterior interval is considered as internervous and intermuscular muscle-sparing technique. However, several reports have proved that the DAA was also associated with muscle damage, particularly to the tensor fascia lata during the exposition with the instruments.

The purpose of this study is to determinate the correlation between the severity of muscle damage during surgery and the functional post operative short and medium term results. We underwent grading visible muscle damage during surgery after implant positioning by a grading system in 5 stages from 0 (intact or a few fibers) to 4 (more than 75% of muscle damage). Functional results were established by Harris Hip Score at 6 weeks and 6 months follow up.

Inclusion Criteria:

• adult (>18 years old),
• patient undergoing primary Total Hip Arthroplasty through Direct Anterior Approach for osteoarthritis

Exclusion Criteria:

• hip dysplasia
• leg length discrepancy greater than 2cm
• history of homolateral hip surgery
• neuromuscular pathology
• patients declining the protocol