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 .
Does highly cross-linked polyethylene wear less than conventional polyethylene in total hip arthroplasty? A double-blind, randomized, and controlled trial using roentgen stereophotogrammetric analysis.
A prospect i ve double-blind , r and omized , and controlled trial was conducted using roentgen stereophotogrammetric analysis ; 54 total hip arthroplasty patients were r and omized to receive either highly cross-linked polyethylene ( HXLPE ) or st and ard ultra-high-molecular-weight polyethylene ( UHMWPE ) liners . The 3-dimensional penetration of the liner was determined over 2 years . For the first 3 months , both polyethylene types had a rapid penetration rate ( HXLPE : 0.22 mm , SD = 0.17 mm ; UHMWPE : 0.21 mm , SD = 0.15 mm ; P = .78 ) . After 3 months , the HXLPE penetration rate ( 0.06 mm/y , SD = 0.06 mm/y ) was significantly lower than the UHMWPE penetration rate ( 0.10 mm/y , SD = 0.07 mm/y ; P = .04 ) . The penetration in the first 3 months was probably caused by creep or bedding in ; from 3 months onward , much of the penetration was probably caused by wear . We conclude that HXLPE has a 40 % lower wear rate as compared with UHMWPE , suggesting that it will perform better in the long term
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 .