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 .
Failure of the Uncoated Titanium ProxiLock Femoral Hip Prosthesis
New prostheses should be evaluated for stability and clinical performance . In a prospect i ve r and omized clinical trial , we implanted 22 titanium ( Ti ) and 20 hydroxyapatite-coated ( HA ) ProxiLock femoral hip prostheses during total hip arthroplasty in 42 patients . The patients were followed for 24 months with clinical , radiographic and radiostereometric analysis . Full weightbearing was allowed immediately postoperatively . One patient with a titanium stem was lost to followup . During the first two months , 34 of the 41 stems subsided and /or rotated towards retroversion , regardless of stem type . At the 24-month followup 35 of the 41 prostheses were either fully stabilized ( 16 HA and 11 Ti stems ) or had clinical irrelevant migration ( four HA and four Ti stems ) . Six Ti prostheses showed continuous migrations with maximums of 4.7 mm translation and 12.2 ° retroversion ; four of these were revised , the other two had no clinical complaints . Clinical relevance : The migration pattern we found indicates insufficient primary fixation of the ProxiLock stem in an immediate full weightbearing protocol . The HA coating improves the secondary stability of the prosthesis compared to the uncoated stem . Early migration is associated with an increased risk of possible future loosening and revision , and therefore we discontinued the use of this prosthesis . Level of Evidence : Therapeutic Level I. See Guidelines for Authors for a complete description of levels of evidence
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 .