Abstract
Background
Proper femoral component placement plays a key role in the success of a total knee replacement (TKR). Controversy exists on which technique should be used to ensure proper femoral component placement. This two-part study compares gap balancing (GB) and measured resection (MR) techniques used in TKR, investigating femoral component position and early clinical outcomes.
Methods
Femoral component position was analyzed in 95 consecutive knees that underwent primary TKR. Both GB and MR cutting blocks from the same knee system were sequentially placed on the operative knee, marking the pin sits. A standardized photograph (Figure) was taken prior to making final femoral cuts. Relative rotation was determined based on measurements made from a commercially available software. Clinical comparison was made using 50 consecutive GB patients and 50 consecutive MR patients. Clinical outcome measures were Knee Society Scores (KSS), knee range of motion (ROM), functional ROM (FROM), tourniquet time, and patients having manipulations under anesthesia (MUA).
Results
The GB technique resulted in relative external and internal rotation of the femoral component in 41% and 17% knees respectively. Forty 42% of knees had no relative rotation. Mean pre and 1 year post-operative knee ROM for the MR cohort was 116.4±14.3° and 115±12.9° respectively, with FROM of 103.0±17.2°. The GB cohort had mean pre and 1 year post-operative knee ROM values of 113.9±10.8° and 116.8±13.6° respectively, with FROM of 96.0±22.5°. Mean 1 year pain and function KSS in the MR cohort were 92.5±10.7 and 85.4±18.9. In the GB cohort, the mean 1 year KSS values were 95.7±6.7 and 84.9±19.58 for pain and function respectively. Clinical outcome measures were not statistically different.
Conclusion
We found that the GB technique resulted in external rotation relative to the MR technique. Despite these intraoperative findings we found no significant clinical differences.
