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 .
Two-year radiostereometric analysis evaluation of femoral head penetration in a challenging population of young total hip arthroplasty patients.
This prospect i ve , r and omized protocol evaluated femoral head penetration after total hip arthroplasty in a young population . Forty-five patients r and omly received either a cross-linked or conventional ultrahigh-molecular-weight polyethylene ( UHMWPE ) liner in a noncemented hemispheric cup ( Trilogy , Zimmer , Warsaw , Ind ) with a 28-mm femoral head . Radiostereometric analysis film pairs , Harris hip , UCLA , SF-12 , and Western Ontario and McMaster Universities scores were obtained through 2 years . Median femoral head penetration was less among cross-linked compared to conventional liners as follows : 0.06 mm ( 0.04 - 0.08 mm ) vs 0.08 mm ( 0.02 - 0.19 mm ) at 6 months , 0.07 mm ( -0.14 to 0.16 mm ) vs 0.11 mm ( 0.01 - 0.27 mm ) at 1 year , and 0.065 mm ( -0.04 to 0.193 mm ) vs 0.169 mm ( 0.09 - 0.22 mm ) at 2 years . Clinical outcomes were similar between the groups . Highly cross-linked UHMWPE demonstrated 55 % less femoral head penetration compared to conventional polyethylene at 2 years . Despite improvements in the manufacturing process and sterilization of conventional UHMWPE , the femoral head penetration rate is unchanged from historical st and ards
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 .