Randelli PS, et al. - A total of 133 individuals were studied to assess the impact of patient-specific instrumentation (PSI) on the rotational alignment of the femoral component in comparison to conventionally implanted total knee arthroplasty (TKA). Researchers performed block randomization to allocated cases in the treatment (PSI) or control group. Computed tomography of the knee was obtained to estimate femoral component rotation to the transepicondylar axis and tibial component slope 2 months after surgery. As compared with conventional instrumentation, they neither observed significant improvement in femoral component rotation nor resulted in a reduction of outliers with PSI.