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 ) .
The Exeter femoral stem continues to migrate during its first decade after implantation
Background Due to its collarless , double-tapered polished design , the Exeter femoral stem is known to migrate distally in the first 5 years after implantation . However , its long-term migration pattern has not been investigated . Patients and methods 39 consecutive patients ( 41 total hip arthroplasties ) received a cemented Exeter stem and had prospect i ve clinical and RSA follow-up . Patients were evaluated postoperatively at 6 , 12 , 26 , and 52 weeks , and annually thereafter . Short-term results have been reported . In this study , the mean length of follow-up was 9.4 years ( SD 3.2 years ) . No patients were lost to follow-up . 15 patients died during follow-up . Results No stems were revised . In 4 stems , fractures of the cement mantle were noted within the first 3 postoperative years . In 3 stems , this result ed in a complete circumferential cement mantle discontinuity . For the 37 well-performing stems , continuous but small migration was measured between 2 and 12 years of follow-up . Continued subsidence of 0.08 mm/year ( 95 % CI : 0.05–0.12 , p < 0.001 ) was seen in combination with continued rotation in retroversion of 0.07 ° /year ( 95 % CI : 0.02–0.12 , p = 0.01 ) . At 10 years of follow-up , mean subsidence was 2.1 ( SD 1.2 ) mm and mean retroversion was 1.8 ° ( SD 2.0 ) . Two-thirds of this occurred during the first 2 postoperative years . In the 3 stems with a complete circumferential cement fracture , a sudden and disproportionately high increase in subsidence was measured in the time period of occurrence . Interpretation The Exeter femoral stem continues to migrate during the first decade after implantation . Absolute stability is not required for good long-term survival if this is compatible with the design of the implant
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 ) .