{"title":"Does the calcar femorale affect the position of uncemented short stems?","authors":"Jan Weidner, Michael Wyatt, Martin Beck","doi":"10.1177/11207000241277687","DOIUrl":null,"url":null,"abstract":"<p><strong>Background and purpose: </strong>Metaphyseal-stabilised short stems rely on sufficient metaphyseal fixation and are inserted by following the medial cortex. This type of stem is used extensively in our institution, and we observed on occasion unintended implant positioning with an increased distance between the implant and the medial cortex. A bony structure within the proximal femur which was first described in 1874 and named the calcar femorale, coincides with this phenomenon.The aim of this study was to investigate the impact of the calcar femorale on the position of a metaphyseal-stabilised short stem.</p><p><strong>Patients and methods: </strong>The frequency of cases with an increased distance between medial cortex and the implanted short stem was analysed in 52 consecutive patients. Additionally, we performed an anatomical CT study with 60 cadaveric femora to obtain more detailed information on the anatomy of the calcar femorale. Detailed measurements regarding the calcar femorale and its relationship to the proximal femur were obtained. From this, we derived implications for the implantation of a short stem prosthesis.</p><p><strong>Results: </strong>In 50% of all cases, we found an increased gap between the stem and the medial cortex. An increased gap did not significantly affect stem size, position, or subsidence rate, but in cases with an increased gap we found fewer stems with a radiologically optimum fit. The calcar could be identified in all 60 cadavers. The calcar femorale angle showed a high correlation with the mechanical antetorsion (0.87, <i>p</i> = 0.02) and the functional antetorsion (0.86, <i>p</i> = 0.05) of the femur.</p><p><strong>Conclusions: </strong>The calcar femorale is a consistent anatomical structure which may be the cause for an increased gap medial to the short stem in 50% of our cases. It limits the intramedullary space and influences both stem size and orientation. The CF angle which correlates with femoral antetorsion may influence the anteversion of the stem.</p>","PeriodicalId":12911,"journal":{"name":"HIP International","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"HIP International","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1177/11207000241277687","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/9/16 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"ORTHOPEDICS","Score":null,"Total":0}
引用次数: 0
Abstract
Background and purpose: Metaphyseal-stabilised short stems rely on sufficient metaphyseal fixation and are inserted by following the medial cortex. This type of stem is used extensively in our institution, and we observed on occasion unintended implant positioning with an increased distance between the implant and the medial cortex. A bony structure within the proximal femur which was first described in 1874 and named the calcar femorale, coincides with this phenomenon.The aim of this study was to investigate the impact of the calcar femorale on the position of a metaphyseal-stabilised short stem.
Patients and methods: The frequency of cases with an increased distance between medial cortex and the implanted short stem was analysed in 52 consecutive patients. Additionally, we performed an anatomical CT study with 60 cadaveric femora to obtain more detailed information on the anatomy of the calcar femorale. Detailed measurements regarding the calcar femorale and its relationship to the proximal femur were obtained. From this, we derived implications for the implantation of a short stem prosthesis.
Results: In 50% of all cases, we found an increased gap between the stem and the medial cortex. An increased gap did not significantly affect stem size, position, or subsidence rate, but in cases with an increased gap we found fewer stems with a radiologically optimum fit. The calcar could be identified in all 60 cadavers. The calcar femorale angle showed a high correlation with the mechanical antetorsion (0.87, p = 0.02) and the functional antetorsion (0.86, p = 0.05) of the femur.
Conclusions: The calcar femorale is a consistent anatomical structure which may be the cause for an increased gap medial to the short stem in 50% of our cases. It limits the intramedullary space and influences both stem size and orientation. The CF angle which correlates with femoral antetorsion may influence the anteversion of the stem.
期刊介绍:
HIP International is the official journal of the European Hip Society. It is the only international, peer-reviewed, bi-monthly journal dedicated to diseases of the hip. HIP International considers contributions relating to hip surgery, traumatology of the hip, prosthetic surgery, biomechanics, and basic sciences relating to the hip. HIP International invites reviews from leading specialists with the aim of informing its readers of current evidence-based best practice.
The journal also publishes supplements containing proceedings of symposia, special meetings or articles of special educational merit.
HIP International is divided into six independent sections led by editors of the highest scientific merit. These sections are:
• Biomaterials
• Biomechanics
• Conservative Hip Surgery
• Paediatrics
• Primary and Revision Hip Arthroplasty
• Traumatology