Muscle Damage of the TFL (Tensor Fascia Latae) During Total Hip Arthroplasty (THA) Through Direct Anterior Approach (DAA)

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.

• Data collection and self-administered questionnaire (Other): Data collection and self-administered questionnaire (HHS and SF-36)

Primary outcomes

• Correlation between post operative functional results and TFL muscle damage [week 6]: Correlation between : * short term post operative functional results, evaluated by Harris Hip score at 6 weeks. Harris Hip score has 10 items with several propositions per each item and total score from 2 to 100 , and * TFL muscle damage grade during surgery evaluated with ATHLAS classification : score 0 (intact or few fibres), 1 (0-25% of fibres), 2 (25-50%), 3 (50-75%) et 4 (>75%)

Secondary outcomes

• Harris Hip score 6 months [6 months]: Result of Harris Hip score at 6 months Harris Hip score has 10 items with several propositions per each item and total score from 2 to 100 ,
• Quality of life scale [6 weeks, 6 months]: Evolution of SF-36 questionnaire score between 6 weeks and 6 months after total hip arthroplasty

Sex: All, ages: 18 Years to any

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