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*Arun Mullaji - . - Mumbai, IndiaGautam Shetty - BREACH CANDY HOSPITAL - Mumbai, INDIA*Email: arunmullaji@hotmail.comThe weight bearing axis of the limb goes from the pelvis to the ground and includes the hindfoot. However, the influence ofhindfoot alignment on mechanical axis deviation and overall limb alignment after total knee arthroplasty (TKA) is unknown.This study aimed to assess the change in hindfoot alignment after TKA for knee osteoarthritis, the difference in mechanical axisdeviation at the knee when calculated using the ground mechanical axis as compared to the conventional mechanical axis, andthe effect of hindfoot alignment on the overall postoperative limb alignment after TKA.We evaluated the pre- and postoperative hip-knee-ankle (HKA) angle, conventional mechanical axis deviation (CMAD), groundmechanical axis deviation (GMAD), and tibiocalcaneal angle (TCA) in 125 patients who underwent 165 consecutiveTKAs.Overall, the change in pre- and postoperative mean TCA was not significant (p=0.48) whereas it was significant (p=0.01) inknees with ≥15° deformity where the hindfoot valgus decreased by approximately 25%. Preoperatively, there was no significantdifference between mean CMAD and mean GMAD whereas postoperatively the difference was significant (p=0.0001). Hindfootvalgus alignment of ≥10° was present in 22.5% of limbs and 29% limbs had a postoperative GMAD of ≥10 mm in spite of thelimb alignment being restored to within 3° of neutral after TKA.Despite accurate restoration of limb alignment after TKA, as a result of persistent hindfoot valgus alignment the groundmechanical axis may pass lateral to the centre of the knee joint - with potential detrimental effects on bone, ligaments andimplants.Thursday, October 7, 2010, 13:30-14:10Session B5: Computer Navigation in TKR 1Computer-Assisted Total Knee Arthroplasty in Arthritis With RecurvatumDeformity*Arun Mullaji - . - Mumbai, IndiaLingaraju AP - The Arthritis Clinic - Mumbai, IndiaGautam Shetty - BREACH CANDY HOSPITAL - Mumbai, INDIA*Email: arunmullaji@hotmail.comGenu recurvatum deformity is uncommon in arthritic knees undergoing total knee arthroplasty (TKA). We retrospectivelyanalysed radiographs and navigation data to determine the clinical and radiographic results of computer-assisted TKA in kneearthritis with recurvatum deformity.Based on alignment data obtained during computer assisted (CAS) TKA, 40 arthritic knees (36 patients) with a recurvatumdeformity of at least 5° were identified. The mean recurvatum deformity was 8.7° (6° to 14°). On preoperative standing hipankleradiographs, 23 limbs (57.5%) had a mean varus deformity of 169.4° (153° to 178°) and 17 limbshad a mean valgusdeformity of 189.2° (182° to 224°). The intraoperative navigation data showed mean tibial resection of 7.5mm (4.6 to 13.4mm)and distal femur resection of 7.5mm (3.3 to 13mm) with a mean final extension gap of 21.2mm and a flexion gap at 90° of21.1mm and on extension. On table, the mean knee deformity in sagittal plane was 3° flexion (1.5° to 4.5° flexion).Postoperatively, the mean HKA angle on standing hip-ankle radiographs was 179.2° (177° to 182°). On postoperative lateralradiographs, joint line in extension was moved distally in 35 limbs by 2.3mm (0.3 to 4mm) and proximally in 5 limbs by 2.2mm(2.2 to 2.4mm); the mean preoperative posterior femoral offset of 28.7 mm changed to 27.9 mmpostoperatively. At a meanfollow up 28 months (14- 48 months) the knee, function, and pain scores improved by 61, 48, and 28 points, respectively andthere was no recurrence of recurvatum deformity at final follow up.Genu recurvatum is a notoriously difficult condition to address at TKA. The challenges are to be able to detect it at surgery andtake appropriate measures in terms of resection and releases to correct it satisfactorily. Computer assisted TKA helps to achieveexcellent deformity correction, limb alignment, gap balancing and function in patients with recurvatum deformity by accuratelyquantifying and helping to modify the amount of bone cuts and titrate soft tissue release.file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]