Global Recall of a Radial Head Prosthesis: Case Series, Literature Review and Possible Causes
Refereed conference paper presented and published in conference proceedings
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摘要Introduction: In December 2016, there was a class II medical device recall by US FDA about a radial head prosthesis due to loosening at the stem-bone interface. This prosthesis had been used in our locality but the exact causes were still unknown. We reviewed the clinical courses, radiological progression of this system, and analyzed potential reasons of early loosening.
Methodology: Total 4 cases were performed in our centre from 2015-2016 and all were included. We studied the
demographics, postoperative functional performance and radiological changes.
Results and Analysis: All 4 cases showed X-ray features of loosening between 3-11 months. Progressive radiolucency was present around stem region together with cortical thinning. Patients were followed up for 24-35 months, all have satisfactory elbow function and good range of movement. None of them have elbow instability, and none were revised.
Discussion and Conclusion: Articulation related to radial head is complex and difficult to reproduce. Features that simulate normal radial head anatomy like anatomical radial head, offset with radial shaft, and radial head tilt are absent in this system. Failure to reproduce normal biomechanics lead to stress concentration at bone-implant interface and affect bone ingrowth. Resultant incongruency may produce excessive stress, wear and eccentric loading that lead to early loosening. However, loosen stem in a previously press-fit design can accommodate certain degree of stress incongruency and provide valgus stability and radial length. This may explain the painless loosening in all our patients.
Methodology: Total 4 cases were performed in our centre from 2015-2016 and all were included. We studied the
demographics, postoperative functional performance and radiological changes.
Results and Analysis: All 4 cases showed X-ray features of loosening between 3-11 months. Progressive radiolucency was present around stem region together with cortical thinning. Patients were followed up for 24-35 months, all have satisfactory elbow function and good range of movement. None of them have elbow instability, and none were revised.
Discussion and Conclusion: Articulation related to radial head is complex and difficult to reproduce. Features that simulate normal radial head anatomy like anatomical radial head, offset with radial shaft, and radial head tilt are absent in this system. Failure to reproduce normal biomechanics lead to stress concentration at bone-implant interface and affect bone ingrowth. Resultant incongruency may produce excessive stress, wear and eccentric loading that lead to early loosening. However, loosen stem in a previously press-fit design can accommodate certain degree of stress incongruency and provide valgus stability and radial length. This may explain the painless loosening in all our patients.
出版社接受日期03.11.2018
著者YC Lau, YC Siu, CM Ma, KK Ling
會議名稱The Hong Kong Orthopaedic Association 38th Annual Congress
會議開始日03.11.2018
會議完結日04.11.2018
會議地點Hong Kong
會議國家/地區香港
會議論文集題名The Hong Kong Orthopaedic Association 38th Annual Congress Programme & Abstract
出版年份2018
月份11
出版地Hong Kong
語言英式英語
關鍵詞Radial head prosthesis
