ABSTRACT
Background: Osteoarthritis of the knee is among the most common contributing causes of global disability, prevalent in 20 to 40 % of those over 75 years of age. Total Knee Arthroplasty (TKA), today; is the final treatment option provided to patients with unsalvageable, severely arthritic, painful and deformed knees. TKA with a postoperative mechanical axis of <3º varus or valgus have better long-term survival. Despite the continuing improvement in mechanical alignment systems, it has been estimated that the error in tibial and femoral alignment of over 3° occurs in about 10% of total knee arthroplasties even when they are carried out by well-trained surgeons using the most up-to-date mechanical alignment tools. Computer Assisted TKA has shown to reduce outliers of mechanical leg axis (>3° valgus/varus deviation) compared to the conventional technique.We hypothesized that Computer Assisted Total Knee Arthroplasty will offer a good clinical and functional outcome in patients. Methods:This was a prospective study done in Department of Orthopaedics at our institute. 53 cases were taken with diagnosis of osteoarthritis of knee joint from May 2015 to June 2017. The study was prospective and observational in nature and informed consent was obtained from each patient. Clearance from scientific and ethical committee of the institute was obtained. The results of navigation assisted total knee replacements were assessed with Visual Analogue Scale, Knee society knee score and Function Score and radiologically by various component angles and Mechanical Axis Deviation. Results: Mean Mechanical Axis Deviation of 18.04° varus preoperatively (range, 15° -24°) was corrected to 0.28° varus (range 3.5° valgus- 3.3° varus) postoperatively. Mean Knee Society score improved from 2.415 (range 0-14) to 82.55 (range 50 -95), and function score from 23.40 (range, 0 -65) to 82.55(range 50-95) at minimum 12 months of follow up. The mean pre-operative VAS was 7.6 and showed linear improvement post operatively to 4.0 at 1 month, 2.37 at 3 months, 1.07 at 6 months and finally 0.64 at 12 months. The mean component angles of implants in Tibia and Femur post-operatively were measured as Coronal femoral angle – 90.025°, Sagittal femoral angle – 90.425°, Coronal tibial angle – 90.311°, Sagittal tibial angle – 88.896°. Conclusion:60.37% excellent and 30.18% good functional outcome along with significant improvements in knee society knee scores and VAS scores was reported. This suggests that computer assisted TKA is a safe, effective and reliable method to alleviate pain and correct deformities in patients with Osteoarthritis of the knee joint. The radiological assessment done Post-operatively confirmed that, CATKA is a significantly accurate tool to correct the deformities.