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 .
Excessive distal migration of fiber-mesh coated femoral stems
Background The surface texture , localization , and magnitude of the surface material applied to the femoral stem can facilitate bone ingrowth and influence the survival of total hip arthroplasties . Clinical and radiographic studies have shown superior bone ingrowth in proximally porous-coated stems with a diaphyseal grit-blasted surface in comparison to a smooth diaphyseal surface . Surface textures — especially porous surface material —have been suggested to have a sealing effect against migration of polyethylene debris along the implant-bone interface and to reduce the inflammatory response , leading to a prolonged implant survival . Patients and methods Between 2004 and 2006 , we conducted a r and omized , controlled trial ( RCT ) involving 50 patients with non-inflammatory arthritis . They received either a distally tapered , extended coated stem or a straight , proximally coated stem . During surgery , tantalum markers were inserted into the greater and lesser trochanter . Implant migration was evaluated at 3 , 12 , and 24 months postoperatively by radiostereometric analysis . The primary endpoint was stem migration 2 years after surgery . Results All femoral components in both groups showed pronounced distal translation , with the highest rate of translation occurring between 0 and 3 months . After 2 years , the mean distal translation was 2.67 ( 95 % CI : –3.93 to –1.42 ) mm for the tapered , extended coated stem and 1.80 ( –2.45 to –1.15 ) mm for the straight , proximally coated stem . Half of the tapered , extended coated stems and two-thirds of the straight , proximally coated stems had migrated more than 1 mm . No difference between the 2 stems could be seen with regard to translation or rotation at any time point . After 2 years , 2 hips have been reoperated due to mechanical loosening of the stem . Interpretation An excessive amount of migration of both stem types was seen 2 years postoperatively . It is of vital importance to follow this patient cohort since radiostereometric analysis is known to be predictive of late implant failure , especially in this study where pronounced early migration was observed . We recommend longer follow-up of both stem types
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 .