INTRODUCTION: A posterior entry point, a neutral tip position and neutral stem alignment are recommended to avoid a thin cement mantle and ensure an optimal outcome in total hip arthroplasty (THA). Our aim was to highlight any influence of surgical approach in obtaining an optimal stem orientation. METHODS: We examined the post-operative, digitised radiographs of 100 (50 each group) polished, tapered Exeter THA, inserted via the antero-lateral or posterior approaches. Stem tip position was assessed in both coronal and sagittal planes and stem alignment was assessed in the coronal plane. RESULTS: There was a significant difference between the two approaches in the sagittal stem tip position only (p=0.01). DISCUSSION: Our results illustrate that a neutral stem tip position in THA is significantly more difficult to obtain with an antero-lateral approach, when compared to the posterior approach. A posterior approach to the hip avoids the cuff of glutei that can lever the proximal stem anteriorly causing an anterior entry point and a posterior stem tip position. We also illustrate how the anatomy of the proximal femur in the sagittal plane makes a neutral stem alignment difficult to achieve with either approach.
INTRODUCTION: A posterior entry point, a neutral tip position and neutral stem alignment are recommended to avoid a thin cement mantle and ensure an optimal outcome in total hip arthroplasty (THA). Our aim was to highlight any influence of surgical approach in obtaining an optimal stem orientation. METHODS: We examined the post-operative, digitised radiographs of 100 (50 each group) polished, tapered Exeter THA, inserted via the antero-lateral or posterior approaches. Stem tip position was assessed in both coronal and sagittal planes and stem alignment was assessed in the coronal plane. RESULTS: There was a significant difference between the two approaches in the sagittal stem tip position only (p=0.01). DISCUSSION: Our results illustrate that a neutral stem tip position in THA is significantly more difficult to obtain with an antero-lateral approach, when compared to the posterior approach. A posterior approach to the hip avoids the cuff of glutei that can lever the proximal stem anteriorly causing an anterior entry point and a posterior stem tip position. We also illustrate how the anatomy of the proximal femur in the sagittal plane makes a neutral stem alignment difficult to achieve with either approach.
Authors: Loes Janssen; Karolina A P Wijnands; Dennis Janssen; Michiel W H E Janssen; Jan W Morrenhof Journal: Clin Orthop Relat Res Date: 2018-06 Impact factor: 4.176