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 .
Highly Cross-Linked Polyethylene in Cemented THA: Randomized Study Of 61 Hips
Highly cross-linked polyethylene ( PE ) has been introduced as an alternative bearing material in total hip arthroplasty ( THA ) because of high wear resistance in laboratory tests but the clinical experience of this material is limited . We evaluated a highly cross-linked PE ( warm irradiated adiabatic melting , absorbed dose , 95 kGy ) in a r and omized study of cemented THAs . Cups of the same design but made of conventionally gamma irradiated PE ( absorbed dose , 25–40 kGy ) constituted the control group . Sixty-one hips ( 30 women , 30 men ) with a median age of 55 years ( range , 35–70 years ) were included . All patients received a Spectron stem with 28-mm CoCr head . Radiostereometric examinations with the patient supine or st and ing were done at regular intervals . Wear was measured with the patient in the supine position from the first postoperative week , whereas examinations done with the patient st and ing were initiated 3 months after the operation . Dual xray absorptiometry and conventional radiography were used to evaluate the bone mineral density and the radiolucencies around the acetabular component .  Fifty-two patients ( 53 hips ; 25 highly cross-linked , 28 control ) have been followed up for 2 years . At the 2-year followup , the highly cross-linked cups showed 50 % reduction of proximal wear compared with the control group , when the patients were studied st and ing . When evaluated supine , the difference in proximal wear did not reach significance . The migration of the socket , the relative changes of periprosthetic bone mineral density , and the progression of radiolucencies between the immediately postoperative followup and 2-year followup did not differ . Highly cross-linked PE showed increase resistance to wear . Different mechanical properties of the two types of PE studied did not alter the performance of the cup in terms of fixation , periprosthetic bone loss , and radiographic appearance . However , the followup is short and these results are preliminary
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 .