No difference in long-term micromotion between fully cemented and hybrid fixation in revision total knee arthroplasty: a randomized controlled trial

Abstract

Aims Both the femoral and tibial component are usually cemented at revision total knee arthroplasty (rTKA), while stems can be added with either cemented or press-fit (hybrid) fixation. The aim of this study was to compare the long-term stability of rTKA with cemented and press-fitted stems, using radiostereometric analysis (RSA). Methods This is a follow-up of a randomized controlled trial, initially involving 32 patients, of whom 19 (nine cemented, ten hybrid) were available for follow-up ten years postoperatively, when further RSA measurements were made. Micromotion of the femoral and tibial components was assessed using model-based RSA software (RSAcore). The clinical outcome was evaluated using the Knee Society Score (KSS), the Knee injury and Osteoarthritis Outcome Score (KOOS), and visual analogue scale (pain and satisfaction). Results The median total femoral translation and rotation at ten years were 0.39 mm (interquartile range (IQR) 0.20 to 0.54) and 0.59° (IQR 0.46° to 0.73°) for the cemented group and 0.70 mm (IQR 0.15 to 0.77) and 0.78° (IQR 0.47° to 1.43°) for the hybrid group. For the tibial components this was 0.38 mm (IQR 0.33 to 0.85) and 0.98° (IQR 0.38° to 1.34°) for the cemented group and 0.42 mm (IQR 0.30 to 0.52) and 0.72° (IQR 0.62° to 0.82°) for the hybrid group. None of these values were significantly different between the two groups and there were no significant differences between the clinical scores in the two groups at this time. There was only one re-revision, in the hybrid group, for infection and not for aseptic loosening. Conclusion These results show good long-term fixation with no difference in micromotion and clinical outcome between fully cemented and hybrid fixation in rTKA, which builds on earlier short- to mid-term results. The patients all had type I or II osseous defects, which may in part explain the good results. Cite this article: Bone Joint J 2022;104-B(7):875–883.

Acceptable migration of a fully cemented rotating hinge-type knee revision system measured in 20 patients with model-based RSA with a 2-year follow-up

“…Although a significant number of implants showed continuous migration or a high degree of micromotion (> 1 mm or > 1°), longer follow-up RSA in revision knee surgery with condylar implants did not show signs of aseptic loosening for this potential group at risk ( 4 , 6 ). In addition, a retrospective analysis of a fully cemented Legion HK cohort showed only 1 femoral component loosening in 147 cases with a mean follow-up of 3.8 years ( 16 ).…”

“…The degree of micromotion assessed by RSA in the first 2 years after surgery is associated with late revision for aseptic loosening in primary total knee arthroplasty (TKA) ( 2 , 3 ). From the sparse data available on condylar revision knee implants, it can be observed that higher degrees of micromotion do not result in later aseptic loosening ( 4 - 6 ).…”

Achieving Correct Balance in Total Knee Arthroplasty with Fixed Varus Deformity

“…Given the increased level of constraint, higher forces are transmitted to the bone-implant interface, so to prevent micromotion and implant loosening, stemmed implants are utilized to enhance fixation and participate in load-sharing. Stems may be press-fit or cemented per surgeon preference, taking into account specific patient factors including bone quality and pre-existing femoral deformity 16 .…”

What’s New in Adult Reconstructive Knee Surgery

“…To enlarge the area of the osseous interface and decrease forces on weakened bone, components with stems are often used, and these can be fully cemented or press-fit. Mills et al 60 , using radiostereometric analysis, compared the long-term stability of revision total knee replacements with either fully cemented or press-fitted stems (hybrid fixation). Their findings showed good long-term fixation with no difference in micromotion and PROMs (at the 10-year follow-up) between fully cemented and hybrid fixation of stems in patients with Anderson Orthopaedic Research Institute type-I or II bone defects.…”