To investigate the qualitative rotation alignment of components in total knee arthroplasty and the accuracy and the effectiveness of Bone Morphing computer assisted system when qualitatively practicing.
From November 2002 to June 2003, 21 patients with three compartments osteoarthritis (21 knees) were treated by primary total knee arthroplasty after the conservative medical treatment failed, with the assistance of a "Bone Morphing" Ceravision System, implanted posterior stabilized total knee prosthesis. Twenty-one patients included 5 males (5 knees) and 16 females (16 knees) with an average age of 72.4 years (64-79 years). The locations were left knee in 10 cases and right knee in 11 cases. The patients suffered from knee pain and limitation of movement from 2 to 10 years. There were 14 genu varum and 7 genu valgum preoperatively. The relative preoperative, intraoperative and postoperative data from clinical check-up, the X-ray films and the intraoperative components rotational alignment real-time records in CD Rom were analyzed.
All operative incisions healed up by first intension. Twenty-one patients were followed up 12-16 months (mean 13.3 months). For the achievement of proper lower limb alignment and normal frontal laxity of knee, rotational alignment of femoral components was from internal rotation (IR) 1 degree to external rotation (ER) 5 degrees, tibial components from IR 0 degree to ER 5 degrees. In patients with genu varum, the rotational alignment of the femoral components was ER 1 degree-ER 5 degrees, of tibial components ER 2 degrees-ER 5 degrees. In patients withgenu valgum, the rotational alignment of femoral components was IR 1 degree-ER 4 degrees, of tibial components IR 0 degree-ER 4 degrees. After 3 months of operation, the mean flexion angle measured as range of motion (ROM) was 115 degrees (105-130 degrees), the frontal laxsity measured as 0.2-0.5 cm (mean 0.27 cm) of internal laxity and 1.0-2.5 cm (mean 1.7 cm) for external laxity, there were no knee pain, paterllar instability or dislocation and abnormal knee frontal laxity.
Using Bone Morphing computer-assisted system can optimise the individual components rotation alignment accurately.