After stratification on follow-up time and age , the revision rates were not substantially different , aside for younger patients in short term from studies with short-term follow-up .
Conclusion No essential differences between the two design s were observed .
MB and FB UKA design s have comparable revision rates .
Purpose Two design concepts are currently used for unicondylar knee arthroplasty ( UKA ) prostheses :  fixed bearing ( FB ) and mobile bearing ( MB ) .
While MB prostheses have theoretical advantages over their FB counterparts , it is not clear whether they are associated with better outcomes .
Comparison of a mobile with a fixed tibial bearing unicompartimental knee prosthesis: a prospective randomized trial using a dedicated outcome score.
Between February 1996 and December 1997 , forty consecutive patients with medial compartment knee arthritis were assigned r and omly into two groups . All underwent a unicompartimental knee replacement . The tibial prosthesis in group A ( 20 knees ) had a fixed bearing and in group B ( 20 knees ) a mobile bearing . The average age was 69 . Five in group A and 71 in group B. Pre-operatively , and at an average follow-up of 5.7 years , all the knees were assessed using both a dedicated UKR score specifically developed and adopted by the Italian Orthopaedic Unicompartimental Knee Replacement Users Group ( GIUM ) and the Knee Society Score . During surgery in group B we experienced a medial tibial plateau fracture fixed intra-operatively . One prosthesis in group A required an early revision to a TKR because of a continuous pain without any evident sign of loosening . There were no meniscal dislocations in group B. No statistically significant difference in outcome was observed between the two groups at the latest follow-up
After stratification on follow-up time and age , the revision rates were not substantially different , aside for younger patients in short term from studies with short-term follow-up .
Conclusion No essential differences between the two design s were observed .
MB and FB UKA design s have comparable revision rates .
Purpose Two design concepts are currently used for unicondylar knee arthroplasty ( UKA ) prostheses :  fixed bearing ( FB ) and mobile bearing ( MB ) .
While MB prostheses have theoretical advantages over their FB counterparts , it is not clear whether they are associated with better outcomes .