Computer-assisted revision total knee arthroplasty does not improve postoperative knee prosthesis alignment compared to the conventional technique

PURPOSE: Computer-assisted surgery (CAS) during primary total knee arthroplasty (TKA) prosthesis alignment. However, literature on its use during revision TKA (rTKA) is scarce. Moreover, the effect of CAS during rTKA on rotational alignment of the prosthesis has not been described yet. The purpose of this study was to assess the effect of CAS during rTKA, focusing on the number of outliers and coronal, sagittal and rotational prosthetic alignment compared to conventional rTKA.

METHODS: A prospective cohort study comparing CAS-rTKA with a historical control group (CON-rTKA). The CAS-rTKA group (54 patients/62 knees) underwent rTKA using imageless CAS between 2012 and 2017. The CON-rTKA group (13 patients/23 knees) was operated using the conventional technique between 2002 and 2012. Postoperative alignment was measured using the EOS-2D/3D system (coronal and sagittal planes) and computed tomography scan (rotation).

RESULTS: No significant differences between the CAS-rTKA and CON-rTKA groups were found for coronal and sagittal alignment regarding the mechanical angle of the leg ( p  = 0.08), mechanical lateral distal femoral angle ( p  = 0.87), mechanical medial proximal tibial angle ( p  = 0.40), anatomical proximal posterior tibial angle ( p  = 0.43) nor femoral ( p  = 0.80) and tibial rotation ( p  = 0.15). For the proportions of coronal, sagittal and rotational outliers, no significant differences were found either.

CONCLUSION: This study showed no evidence that use of CAS during rTKA leads to improved coronal, sagittal or rotational alignment of knee prostheses or a difference of outliers between the groups.

LEVEL OF EVIDENCE: Level III, therapeutic.