Revision total knee arthroplasty for component malrotation is highly beneficial: a case control study

Component malrotation is a recognized cause of post total knee arthroplasty (TKA) pain. We reviewed 24 patients who had TKA revision due to component malrotation as the only objective abnormality. Mean combined component rotation was 6.8° excessive internal rotation, as documented by computed tomography. Twenty-four matched control patients had TKA revision due to aseptic loosening. Mean follow-up was 37 months. Preoperative Knee Society Score improved by 49 points at 6 months postoperatively for the malrotation patients and by 39 for the loosening patients. At last follow-up, Knee Society Score was 80 for the malrotation group and 75 for the loosening group. We recommend the use of computed tomography scans in evaluation of all patients with early painful TKAs and no objective evidence of infection. When component malrotation is demonstrated, early revision should be considered.