Martin JR et al. – This study evaluated preoperative alignment and its correlation with degree of eventual varus collapse in patients who underwent total knee arthroplasty (TKA) before revision. The study concluded that tibial varus collapse is an uncommon cause of failure following primary TKA. The common findings in this group of patients include preoperative varus deformity, postoperative medial tibial bone loss, and obesity. Hence, increased tibial stem lengths should be considered in patients with a preoperative varus deformity, small tibial implant size, and a body mass index (BMI) ≥35 kg/m2 undergoing primary TKA.

Methods

• A total of 1106 revision TKAs were performed and 35 patients of these were revised following tibial varus collapse.
• Primary TKA was performed in 27 patients.
• Anteroposterior knee radiographs were used for recording coronal alignment of the knee and medial tibial bone loss was recorded at the final follow–up.

Results

• Average BMI was 38 kg/m2, and preoperative varus deformity (4.2 degrees varus) was observed in 26 of 27 patients and all were corrected to a valgus coronal alignment immediately postoperatively.
• Coronal alignment following varus collapse in 24 of 27 patients were within 2 degrees of their preoperative alignment (5.8 degrees varus), and 25 of 27 patients had radiographic medial tibial bone loss before varus collapse.