This RCT asked whether kinematic alignment (KA) within a restrictive safe zone produces better quantitative soft-tissue balance than mechanical alignment (MA) in TKA. Balance was measured objectively with a pressure sensor, defined as an intercompartmental pressure difference (ICPD) of 15 psi or less. The trial enrolled 125 patients (138 knees) and measured ICPDs at 10°, 45°, and 90° before any balancing procedures were performed.
The core debate in TKA alignment is whether restoring the patient's native (constitutional) knee anatomy produces better soft-tissue balance than imposing a standardized neutral mechanical axis. This trial provides objective intraoperative data — not just patient-reported scores — to address that question directly.
The key number to know: 80% vs 35% of knees achieved optimal balance before any releases or recuts in KA versus MA. That gap is the argument for KA's biomechanical premise.
The lift-off data carries a board-relevant mechanistic point. Lateral compartment lift-off dominated the MA group, which the authors attribute to MCL overtightening when a constitutionally varus knee is corrected to neutral. If you align a varus knee to 0° HKA, the medial side gets relatively tighter — the sensor is catching what the surgeon's hands miss.
The one-year outcomes were equivalent, but interpret that carefully: the trial's ethics required balancing both groups once imbalance was confirmed, so many MA knees received tibial recuts that functionally approximated KA. The cleaner finding is the intraoperative balance data before any correction. Long-term comparative data on revision rates and implant survivorship are still needed.
This RCT asked whether kinematic alignment (KA) within a restrictive safe zone produces better quantitative soft-tissue balance than mechanical alignment (MA) in TKA. Balance was measured objectively with a pressure sensor, defined as an intercompartmental pressure difference (ICPD) of 15 psi or less. The trial enrolled 125 patients (138 knees) and measured ICPDs at 10°, 45°, and 90° before any balancing procedures were performed.
The core debate in TKA alignment is whether restoring the patient's native (constitutional) knee anatomy produces better soft-tissue balance than imposing a standardized neutral mechanical axis. This trial provides objective intraoperative data — not just patient-reported scores — to address that question directly.
The key number to know: 80% vs 35% of knees achieved optimal balance before any releases or recuts in KA versus MA. That gap is the argument for KA's biomechanical premise.
The lift-off data carries a board-relevant mechanistic point. Lateral compartment lift-off dominated the MA group, which the authors attribute to MCL overtightening when a constitutionally varus knee is corrected to neutral. If you align a varus knee to 0° HKA, the medial side gets relatively tighter — the sensor is catching what the surgeon's hands miss.
The one-year outcomes were equivalent, but interpret that carefully: the trial's ethics required balancing both groups once imbalance was confirmed, so many MA knees received tibial recuts that functionally approximated KA. The cleaner finding is the intraoperative balance data before any correction. Long-term comparative data on revision rates and implant survivorship are still needed.