No differences in clinical outcomes between fixed- and mobile-bearing computer-assisted total knee arthroplasties and no correlations between navigation data and clinical scores

Abstract

PurposeThe theoretical advantages of mobile-bearing (MB) designs over the conventional fixed bearings (FBs) for total knee arthroplasty (TKA) have not been proved yet through clinical studies. The aim of the study was to test whether the MB design has advantages in terms of better clinical outcomes when compared to FB. Furthermore, the relationships between intra-operative obtained implant positioning data and the clinical scores were analysed.MethodsA total of 99 patients were randomized into the FB or the MB group. All patients received the same posterior cruciate retaining implants and were operated with the use of a computer-assisted navigation system. The clinical outcomes of both groups were compared pre-operatively, at 1 year, and at a mean follow-up time of 4 years after surgery.ResultsThe MB implants showed no advantages over the FB when comparing the Knee Society Scores, the Oxford Score, the range of movement (ROM) and pain intensity of the patients in both groups at 1 and 4 years after surgery. There were no relationships between the computer navigation data and the clinical scores.ConclusionsIn view of the 4-year results, there is no evidence to support the recommendation of one design over the other in terms of better clinical outcome scores, higher ROM or lower pain rates. Long-term follow-up results may be necessary, including survival rates. Further research comparing different TKA designs should also include standardized performance-based tests.Level of evidenceProspective study (Randomized controlled trial with adequate statistical power to detect differences), Level I.

No Benefit of Computer-assisted TKA: 10-year Results of a Prospective Randomized Study

“…With the numbers available, we found no survivorship advantage in patients treated with CAS TKA 10 years after surgery. Although our results are consistent with the results from others authors [3,9,11,14,16,19,20] (Table 3), our series was not adequately powered for survival analysis. Because we found the same implant survivorship between the groups (if aseptic loosening was defined as the endpoint), a post hoc analysis evaluated that 1500 patients would be needed in each group to be able to detect a 2% survivorship difference 10 years after surgery.…”

Mobile-bearing insert used with total knee arthroplasty does not rotate on the tibial tray during a squatting activity: a cross-sectional study

“…Thirteen knees of 11 subjects (3 males and 8 females) were evaluated in this study ( 9,134.9] at 1 year, respectively. There were no statistically significant differences between data at the two time-points for either active ROM (p = 0.173) or passive ROM (p = 0.196).…”

“…It was theorized that mobile-bearing total knee arthroplasty (TKA) should allow self-alignment of the polyethylene insert with the femoral component in order to lessen polyethylene surface stresses, minimize post-cam impingement, and possibly increase polyethylene longevity [1]. However, many studies failed to prove that mobile-bearing insert contributed to reduce insert wear or risk of loosening, as well as to improve clinical outcomes such as range of motion, functional scores, and pain relief [2][3][4][5][6][7][8][9][10]. Moreover, none of the studies utilizing an accurate kinematic analysis system have proven that femoral-tibial component kinematics differs between mobile-bearing and fixed-bearing inserts [11][12][13].…”

Surgically modifiable factors measured by computer-navigation together with patient-specific factors predict knee society score after total knee arthroplasty

“…This study is a secondary analysis of data obtained during a prospective randomized clinical trial designed to investigate the effects of mobile bearing (MB) vs. fixed-bearing (FB) TKA implants on clinical scores [ 26 ].…”

“…Since there were no significant differences between the KSS scores in the fixed- and mobile-bearing groups at any measurement time, and no significant differences when comparing the ROM of both groups across the follow-up assessments [ 26 ], all patients were pooled into one group for the purpose of this secondary analysis of the data.…”