Coronal Alignment in Revision Total Knee Arthroplasty: A Comparison of Cemented Vs Press-Fit Stems for Restoring Mechanical Axis

Background: Restoring a neutral coronal alignment in revision total knee arthroplasty (rTKA) is paramount. Stem length and fixation type influence final limb alignment. This study compared overall limb alignment, measured by hip-knee-ankle (HKA) angle, in revisions using short-cemented (<75 mm), long-cemented (>75 mm), and press-fit stems. Secondary aims included evaluating coronal and sagittal alignment of tibial and femoral components and assessing canal fill ratio (CFR) in the press-fit group. Methods: A retrospective multicenter review of 124 rTKAs from January 2019 to January 2022 was conducted. Included cases had revision of both femoral and tibial components using stems, with postoperative weight-bearing radiographs. Patients were divided into 3 groups based on stem type. Radiographic assessments included HKA, mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and CFR. analysis of variance and chi-square tests were used for statistical analysis. Results: Data from 81 rTKAs were analyzed. Mean HKA was similar across all groups (group A: 178.9°, group B: 178.7°, group C: 178.7°; P = .985). No significant differences were found in mLDFA or mMPTA between groups. However, mLDFA showed more variability than mMPTA (P = .021), indicating greater femoral alignment deviation. CFR in press-fit stems averaged 77.3%, with no significant side-to-side differences. Conclusions: Short-cemented stems achieved alignment comparable to long-cemented and press-fit stems. Femoral alignment was more variable than tibial. Short-cemented stems provide a flexible option with reliable alignment outcomes.