49836
document
Superior fixation of pegged trabecular metal over screw-fixed pegged porous titanium fiber mesh : a randomized clinical RSA study on cementless tibial components . BACKGROUND AND PURPOSE Lasting stability of cementless implants depends on osseointegration into the implant surface , and long-term implant fixation can be predicted using radiostereometric analysis ( RSA ) with short-term follow-up . We hypothesized that there would be improved fixation of high-porosity trabecular metal ( TM ) tibial components compared to low-porosity titanium pegged porous fiber-metal ( Ti ) polyethylene metal backings . METHODS In a prospective , parallel-group , randomized unblinded clinical trial , we compared cementless tibial components in patients aged 70 years and younger with osteoarthritis . The pre-study sample size calculation was 22 patients per group . 25 TM tibial components were fixed press-fit by 2 hexagonal pegs ( TM group ) and 25 Ti tibial components were fixed press-fit and by 4 supplemental screws ( Ti group ) . Stereo radiographs for evaluation of absolute component migration ( primary effect size ) and single-direction absolute component migration ( secondary effect size ) were obtained within the first postoperative week and at 6 weeks , 6 months , 1 year , and 2 years . American Knee Society score was used for clinical assessment preoperatively , and at 1 and 2 years . RESULTS There were no intraoperative complications , and no postoperative infections or revisions . All patients had improved function and regained full extension . All tibial components migrated initially . Most migration of the TM components ( n = 24 ) occurred within the first 3 months after surgery whereas migration of the Ti components ( n = 22 ) appeared to stabilize first after 1 year . The TM components migrated less than the Ti components at 1 year ( p = 0.01 ) and 2 years ( p = 0.004 ) . INTERPRETATION We conclude that the mechanical fixation of TM tibial components is superior to that of screw-fixed Ti tibial components . We expect long-term implant survival to be better with the TM tibial component .
49837
Intervention_Physical
pegged trabecular metal
49838
Intervention_Physical
screw-fixed pegged porous titanium fiber mesh
49839
Intervention_Surgical
high-porosity trabecular metal ( TM ) tibial components
49840
Intervention_Surgical
low-porosity titanium pegged porous fiber-metal ( Ti )
49841
Intervention_Surgical
cementless tibial components
49842
Intervention_Surgical
TM
49843
Intervention_Surgical
25 Ti tibial components were fixed press-fit and by 4 supplemental screws
49844
Intervention_Physical
TM
49845
Intervention_Physical
Ti
49846
Intervention_Physical
TM
49847
Intervention_Physical
Ti
49848
Intervention_Physical
Ti
49849
Intervention_Physical
TM
49850
Outcome_Other
stability
49851
Outcome_Physical
fixation
49852
Outcome_Physical
American Knee Society score
49853
Outcome_Adverse-effects
intraoperative complications
49854
Outcome_Adverse-effects
no postoperative infections
49855
Outcome_Adverse-effects
revisions
49856
Outcome_Physical
improved function and regained full extension
49857
Outcome_Mental
migrated
49858
Outcome_Physical
migration of the TM components
49859
Outcome_Mortality
long-term implant survival
49860
Participant_Condition
components in patients aged 70 years and younger with osteoarthritis .
49861
Participant_Age
All patients