Cemented and uncemented tibial components had different migration patterns .
For cemented tibial components there was no difference in migration between all-poly and metal-backed components , between mobile bearing and fixed bearing , between cruciate retaining and posterior stabilized .
Furthermore , no difference existed between TKR measured with model-based RSA or marker-based RSA methods .
For uncemented TKR there was some variation in migration with the highest migration for uncoated TKR .
Interpretation - The results from this meta- analysis on  RSA migration of TKR  are in line with both the survival analyses results from joint registries of these TKRs as well as revision rates results from meta-analyses , thus providing further proof for the association between early migration and late revision for loosening .
Purpose - We performed a systematic review and meta-analyses to evaluate the early and long-term migration patterns of  tibial components of TKR of all known RSA studies .
Fixation of high-flexion total knee prostheses: five-year follow-up results of a four-arm randomized controlled clinical and roentgen stereophotogrammetric analysis study.
BACKGROUND High-flexion total knee arthroplasty was introduced to meet the dem and s of daily activity requiring increased knee flexion . However , concerns have been raised regarding the fixation of high-flexion total knee arthroplasty components and increased rates of loosening have been reported . To date , migration , and thus fixation , of high-flexion total knee arthroplasty components has not been analyzed and the preferential bearing type ( mobile or fixed ) is unknown . METHODS Of eighty-six consecutive eligible patients , seventy-four patients ( seventy-eight knees ) scheduled for total knee arthroplasty were r and omized to one of four  Legacy Posterior Stabilized ( LPS ) total knee prosthesis design s : ( 1 ) LPS-Flex mobile , ( 2 ) LPS-Flex fixed , ( 3 ) LPS mobile , and ( 4 ) LPS fixed . The primary outcome was component migration measured with use of Roentgen stereophotogrammetric analysis , and secondary outcomes were postoperative knee flexion and extension and Knee Society Score . Patients were evaluated postoperatively at six , twelve , twenty-six , and fifty-two weeks and annually thereafter . At the five-year follow-up , eight patients had died and two patients were lost to follow-up . Seventy-seven tibial and forty-two femoral components were suitable for migration measurements . RESULTS The overall five-year migration of the seventy-seven tibial components was not significantly different among the four total knee prosthesis design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.02 to 0.25 mm ) and migration was comparable at the two and five-year follow-up . Migration stabilized in all but three components ( two LPS-Flex mobile and one LPS fixed ) ; one of these components has already been revised and was aseptically loose . The overall five-year migration of the forty-two femoral components was comparable among the four design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.01 to 0.18 mm ) and was similar at two and five years postoperatively . One femoral component ( LPS-Flex mobile ) migrated excessively . In patients who had a mean postoperative flexion of ≥ 125 ° or a maximum flexion of ≥ 135 ° during the one to five-year follow-up period , migration of high-flexion components was comparable with that of conventional components and indicative of appropriate fixation . Postoperative flexion , extension , Knee Society Score , and Knee Society Score function were comparable during the five-year follow-up period and at the two and five-year follow-up . CONCLUSIONS The LPS-Flex total knee prosthesis with either a mobile or a fixed bearing had migration comparable that of with its conventional counterpart and is expected to have similar ( excellent ) long-term survival in these patients . LEVEL OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence
Cemented and uncemented tibial components had different migration patterns .
For cemented tibial components there was no difference in migration between all-poly and metal-backed components , between mobile bearing and fixed bearing , between cruciate retaining and posterior stabilized .
Furthermore , no difference existed between TKR measured with model-based RSA or marker-based RSA methods .
For uncemented TKR there was some variation in migration with the highest migration for uncoated TKR .
Interpretation - The results from this meta- analysis on  RSA migration of TKR  are in line with both the survival analyses results from joint registries of these TKRs as well as revision rates results from meta-analyses , thus providing further proof for the association between early migration and late revision for loosening .
Purpose - We performed a systematic review and meta-analyses to evaluate the early and long-term migration patterns of  tibial components of TKR of all known RSA studies .