Patient Reported Outcome Measures ( PROMs ) at six months have been investigated but have not been vali date d against long-term outcomes .
EBRA can be used to investigate acetabular wear but not femoral migration .
OBJECTIVES High failure rates of metal-on-metal hip arthroplasty implants  have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices .
The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage .
We aim ed to identify vali date d surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty ( THA ) .
High long-term loosening rate of conical screw cups
Background  Acetabular screw cups  seem to give high primary stability . We analyzed the migration and loosening behavior of a first-generation screw cup in a longterm follow-up . Patients and methods We examined 92 uncemented titanium alloy conical screw cups prospect ively .  Implant migration was assessed with a digital high-precision method ( EBRA ) with an accuracy of 1.0 mm . Results After mean 11 ( 0.5–18 ) years , 87 patients were available for examination and 5 patients had died . 32 implants had been revised and 7 cases showed radiographic evidence of loosening . The 10-year survival rate was 71 % . Migration of more than 1 mm occurred in 53 hips . Implant survival was strongly associated with an annual migration of greater than 0.2 mm . Interpretation The long-term behavior of this cup is not satisfactory . In spite of extraordinarily high primary implant stability , secondary osseointegration of this cup often fails . The annual migration rate represents a valid parameter for prediction of implant survival
Patient Reported Outcome Measures ( PROMs ) at six months have been investigated but have not been vali date d against long-term outcomes .
EBRA can be used to investigate acetabular wear but not femoral migration .
OBJECTIVES High failure rates of metal-on-metal hip arthroplasty implants  have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices .
The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage .
We aim ed to identify vali date d surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty ( THA ) .