INTERPRETATION The guidelines have improved method ological reporting in RSA studies , but adherence to these guidelines is still relatively low .
BACKGROUND AND PURPOSE Guidelines for st and ardization of  radiostereometry ( RSA )  of implants were published in 2005 to facilitate comparison of outcomes between various research groups .
In this systematic review , we determined how well studies have adhered to these guidelines .
A randomized study on migration of the Spectron EF and the Charnley flanged 40 cemented femoral components using radiostereometric analysis at 2 years
Background and purpose We performed a r and omized study to determine the migration patterns of the Spectron EF femoral stem and to compare them with those of the Charnley stem , which is regarded by many as the gold st and ard for comparison of implants due to its extensive documentation . Patients and methods 150 patients with a mean age of 70 years were r and omized , single-blinded , to receive either a cemented Charnley flanged 40 monoblock , stainless steel , vaquasheen surface femoral stem with a 22.2-mm head ( n = 30 ) or a cemented Spectron EF modular , matte , straight , collared , cobalt-chrome femoral stem with a 28-mm femoral head and a roughened proximal third of the stem ( n = 120 ) . The patients were followed with repeated radiostereometric analysis for 2 years to assess migration . Results At 2 years , stem retroversion was 2.3 ° and 0.7 ° ( p < 0.001 ) and posterior translation was 0.44 mm and 0.17 mm ( p = 0.002 ) for the Charnley group ( n = 26 ) and the Spectron EF group ( n = 74 ) , respectively . Subsidence was 0.26 mm for the Charnley and 0.20 mm for the Spectron EF ( p = 0.5 ) . Interpretation The Spectron EF femoral stem was more stable than the Charnley flanged 40 stem in our study when evaluated at 2 years . In a report from the Norwegian arthroplasty register , the Spectron EF stem had a higher revision rate due to aseptic loosening beyond 5 years than the Charnley . Initial stability is not invariably related to good long-term results . Our results emphasize the importance of prospect i ve long-term follow-up of prosthetic implants in clinical trials and national registries and a stepwise introduction of implants
INTERPRETATION The guidelines have improved method ological reporting in RSA studies , but adherence to these guidelines is still relatively low .
BACKGROUND AND PURPOSE Guidelines for st and ardization of  radiostereometry ( RSA )  of implants were published in 2005 to facilitate comparison of outcomes between various research groups .
In this systematic review , we determined how well studies have adhered to these guidelines .