INTERPRETATION There was a clinical ly relevant association between early migration of acetabular cups  and late revision due to loosening .
BACKGROUND AND PURPOSE The association between excessive early migration of acetabular cups  and late aseptic revision has been scantily reported .
We therefore performed 2 parallel systematic review s and meta-analyses to determine the association between early migration of acetabular cups  and late aseptic revision .
Migration of press-fit cups fixed with poly-L-lactic acid or titanium screws: a randomized study using radiostereometry.
The early migration of porous acetabular cups was studied in 43 patients with osteoarthrosis . The patients were r and omly allocated to additional fixation of the cup with either biodegradable poly-L-lactic acid screws or titanium screws .  Radiostereometric evaluation was done during the first 2 years after the procedure in 43 hips ( 23 with  poly-L-lactic acid screws and 20 with titanium screws ) . At the 2-year follow-up , cups fixed with poly-L-lactic acid screws had migrated significantly more in the proximal-distal ( p < 0.05 ) and medial-lateral ( p < 0.05 ) directions . Cups with titanium screws displayed more pronounced rotations around the longitudinal axis ( p < 0.05 ) . Postoperatively , on the lateral view , there was an increased occurrence of radiolucencies at the dome of the cups fixed with poly-L-lactic acid screws ( p < 0.05 ) . The clinical result did not differ between the two groups . Inferior implant-bone contact in the poly-L-lactic acid group , local changes of the bone quality , and diminishing support of the poly-L-lactic acid screws  caused by their degradation with time could be reasons for the different pattern of migration observed
INTERPRETATION There was a clinical ly relevant association between early migration of acetabular cups  and late revision due to loosening .
BACKGROUND AND PURPOSE The association between excessive early migration of acetabular cups  and late aseptic revision has been scantily reported .
We therefore performed 2 parallel systematic review s and meta-analyses to determine the association between early migration of acetabular cups  and late aseptic revision .