INTERPRETATION There was a clinical ly relevant association between early migration of TKPs and late revision for loosening .
PURPOSE We performed two parallel systematic review s and meta-analyses to determine the association between early migration of tibial components and late aseptic revision .
Postoperative clodronate decreases prosthetic migration: 4–year follow-up of a randomized radiostereometric study of 50 total knee patients
Background We have previously reported that 6 months of oral treatment with clodronate reduced the migration of the NexGen total knee prosthesis during the first postoperative year , as measured by  radiostereometry ( RSA ) . We now report the 4-year results . Methods This was a double-blind r and omized study , using RSA with maximal total point motion ( MTPM ) . Results With analysis according to the “ intention to treat ” principle , the only remaining difference between the groups at 4 years was reduced rotation around the transverse axis ( a secondary variable ) in the clodronate group . However , 3 patients ( all clodronate )  did not take any tablet after surgery . If they are excluded , there was an almost statistically significant difference between the groups at 4 years regarding MTPM from baseline , with the clodronate group showing 25 % less migration . From 1 to 4 years , there was no difference in migration rate by MTPM , but there was a continuous increase in rotation around the transverse axis in the controls , which differed from the clodronate group . There were no cases of aseptic loosening . 2 patients had migration of more than 1.3 mm from baseline to 4 years ; neither of them had taken clodronate . The others had migration of less than 0.9 mm . Interpretation Because migration was clearly reduced by clodronate during the first postoperative year , and there was still a difference at 4 years when analyzed per protocol , it appears likely that this treatment can diminish the risk of loosening . The difference in the number of outliers also points in this direction , and may be more relevant than mean migration values
INTERPRETATION There was a clinical ly relevant association between early migration of TKPs and late revision for loosening .
PURPOSE We performed two parallel systematic review s and meta-analyses to determine the association between early migration of tibial components and late aseptic revision .