Femoral Component Malrotation Following Total Knee Arthroplasty in the Presence of Hypoplasia: Is the Orthopedic Surgeon Aware?

Background This study hypothesizes that patients with femoral condylar hypoplasia who undergo total knee arthroplasty (TKA) may experience femoral component malrotation and that the surgeon performing the operation may not notice it. The aim is to measure the rotational alignment of the femoral components and assess the functional outcomes in these patients. Materials and methods Between December 2018 and December 2022, a total of 96 knees from 80 patients were evaluated. The patients were divided into two groups: one with femoral condylar hypoplasia and one without. Rotational changes and functional outcomes were assessed and compared. Results The study included 24 patients, 12 in Group 1 and 12 in Group 2. The demographic characteristics of the patients were homogeneous. The duration of knee prostheses ranged from two to four years. Femoral condylar hypoplasia was detected in 15% of all patients. All patients with hypoplasia had femoral components in varying degrees of internal rotation. There was no significant difference in functional scores between the two groups. Conclusions The rotation of the femoral component in TKA using the posterior condylar axis is affected by deformities in the condyles. In patients with lateral condylar hypoplasia, using the standard method inevitably results in internal rotation of the femoral component.