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Arthroplasty: A. Kulkarni, P. Partington, D. Kelly, and S. Muller Disc calibration for digital templating in hip replacement J Bone Joint Surg Br 2008; 90-B: 1623-1626 [Abstract] [Full text] [PDF]

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Disc calibration - have we advanced any further?

Graham C Cheung, Carl Meyer   (16 January 2009)

Disc calibration - have we advanced any further? 16 January 2009
Graham C Cheung, Specialist Registrar in Trauma and Orthopaedics Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, UK., Carl Meyer Send letter to journal: Re: Disc calibration - have we advanced any further? gckcheung{at}hotmail.com Graham C Cheung, et al.	Sir, We read this paper with great interest but we would like to make some observations. The study relies on a picture archiving and communication system (PACS) that is able to provide ease of calibration which is not available on all systems. Also, the system requires different sized discs to be produced for each x-ray table. Those patients that are currently the outliers in terms of body mass index may eventually become the norm. Wang et al estimate that, according to current trends, 86.3% of Americans will be overweight or obese by 2030.1 Indeed Johnson et al showed that there has been a decrease in sensitivity in the self diagnosis of being overweight between 1999 and 2007.2 If this is, as they suggest, an error caused by what society perceives as being overweight, this will make deciding who is appropriate for this calibration more inaccurate in the future. By not taking into account the patient's build, we feel that x-ray calibration has not been any further advanced by this study, since the time of acetate templates assumed a standardised magnification. C. Meyer, Specialist Registrar in Trauma and Orthopaedics, G.C. Cheung, Specialist Registrar in Trauma and Orthopaedics, Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, UK. 1. Wang Y, Beydoun MA, Liang L, Caballero B, Kumanyika SK. Will all Americans become overweight or obese? estimating the progression and cost of the US obesity epidemic. Obesity (Silver Spring) 2008;16:2323-30. 2. Johnson F, Cooke L, Croker H, Wardle J. Changing perceptions of weight in Great Britain: comparison of two population surveys. BMJ 2008;337:a494.