Convened under the auspicious of esteemed endorsers - ISTA

Thursday, October 7, 2010, 14:20-15:00Session B6: Computer Navigation in TKR 2Analysis of Outliers in Computer-Assisted Total Knee Arthroplasty*Arun Mullaji - . - Mumbai, IndiaGautam Shetty - BREACH CANDY HOSPITAL - Mumbai, INDIA*Email: arunmullaji@hotmail.comComputer navigation has been advocated as a means to improve limb and component alignment and reduce the number ofoutliers after total knee arthroplasty (TKA). We aimed to determine the alignment outcomes of 1500 consecutivecomputerassistedTKAs performed by a single surgeon, using the same implant, with a minimum 1 year follow-up, and to analyze theoutliers. Based on radiographic analysis, 112 limbs (7.5%) in 109 patients with mechanical axis malalignment of > 3° wereidentified and analyzed.The indication for TKA was osteoarthritis in 107 patients and rheumatoid arthritis in 2 patients. Fifty-eight patients (53%) hadundergone simultaneous bilateral TKA and 13 patients (12%) had a BMI >30. Preoperative varus deformity was seen in 100limbs and valgus deformity in 12 limbs. Thirty limbs (27%) had an extra-articular deformity (2 post HTO limbs, 3 malunitedfractures, 1 stress fracture, 21 severe femoral bowing and 3 tibial bowing) and 21 limbs (19%) had severe lateral laxity orsubluxation. Thirty-eight limbs (34%) had a preoperative deformity of ≤10° and 24 limbs (21.5%) had varus or valgus deformityof >20°.Postoperatively, 11 limbs were malaligned at ±3°, 74 limbs at ±4°, 22 limbs at ±5°, 2 limbs at ±6°, and 2 limbs at ±7°. Coronalplane malalignment of > ±3° of the femoral component was seen in 28 limbs, tibial component in 32 limbs, and both femoraland tibial components in 13 limbs. Twenty-six limbs with preoperative varus deformity had a postoperative valgus alignment of>183° and 3 limbs with valgus deformity had a postoperative varus alignment of