Spacer-Based Gap Balancing in Total Knee Arthroplasty: Clinical Success with a Reproducible Technique

Proper coronal and transverse ligament balancing is an important aspect of total knee arthroplasty (TKA) and has an impact on postoperative outcome. Many variations of the gap balancing technique were described to address this challenge, most of them using various tensioning devices, but none for which the use is widespread. The aim of this paper is to describe a gap technique variant for TKA using spacer blocks and report the clinical results for a cohort of patients on which it was used. A total of 114 TKAs were performed in 101 patients using a standardized surgical technique that integrates ligament balancing with sizing and positioning of the femoral component. Clinical variables were assessed preoperatively and after a mean follow-up of 43 months using the Knee Society score, the Knee injury and Osteoarthritis Outcome Score (KOOS), and the International Knee Documentation Committee (IKDC) score. A significant improvement in every clinical function score was noted at the latest follow-up compared with preoperative values. All the knees except four (96%) were well-balanced at the last follow-up examination; a firm but delayed end-point was noted in the remaining four knees but did not seem to affect patient outcome. The patellar button was centered in the prosthetic trochlear groove for all knees on the postoperative radiographs. Similar improvements in the scores and in range of motion were noted for knees with a preoperative coronal misalignment of 10 degrees or more (n = 26) compared with knees with less than 10 degrees of varus or valgus (n = 77). The described surgical technique appears to be reliable to obtain well-balanced knees and good patellar tracking when performing a primary TKA, even in knees with important coronal misalignment.