Hip external rotation and extension angles for exposure and preparation of the proximal femur in direct anterior total hip arthroplasty: A cadaveric study

Abstract

Introduction:The direct anterior approach (DAA) to total hip arthroplasty (THA) has a known learning curve, largely due to difficulty achieving exposure and visualization of the acetabulum and proximal femur for joint preparation. There is paucity of information on limb positioning and the degree of angulation at which the limb is positioned for adequate visualization. This study aimed to identify the mean angles of limb positioning necessary for adequate exposure when using two Mueller retractors for femoral preparation using traditional table.Materials & methods: A surgeon performed a DAA THA on 11 cadaveric hemipelves, exposing the femoral canal with two simple, robust Mueller retractors. The degree of external rotation and extension of the hip was measured. Results: Of the 11, the mean age was 77.6 years and mean BMI was 27.95. The mean external rotation angle was 56.5 ± 13.5 . The mean extension angle was 19.9 ± 6.6 . Discussion & conclusion: The key technical step in this study incorporated a second robust Mueller retractor on the posterior aspect of the greater trochanter, providing maximum leverage to deliver the femur and achieve visibility while reducing angles of limb positioning thereby reducing complications, and ultimately lessening the learning curve.

Component Placement in Direct Lateral vs Minimally Invasive Anterior Approach in Total Hip Arthroplasty: Radiographic Outcomes From a Prospective Randomized Controlled Trial

“…Adverse events have been reported following the introduction of the MIDA at orthopaedic surgical departments [34,39,40,43,[46][47][48][49][50][51][52][53][54], including serious complications, such as peroperative haemorrhage and fractures, to few or no post-operative complications. Some reports suggest that iatrogenic fractures of the greater trochanter may affect the outcome of THA;…”

“…To our knowledge, there are no previously published trials on department-level learning curves following the introduction of the MIDA approach in THA [34,39,43,[46][47][48][49][50][51][52]83]. Rigorous evaluation of learning curves in surgery may be challenging [32,33], and variations in results may to depend on individual surgeon training and experience [33,40,81,84].…”