Genu recurvatum deformity is uncommon in arthritic knees undergoing total knee arthroplasty (TKA). We retrospectively analysed radiographs and navigation data to determine the clinical and radiographic results of computer-assisted TKA in knee arthritis with recurvatum deformity.

Based on alignment data obtained during computer assisted (CAS) TKA, 40 arthritic knees (36 patients) with a recurvatum deformity of at least 5° were identified. The mean recurvatum deformity was 8.7° (6° to 14°). On preoperative standing hip-ankle radiographs, 23 limbs (57.5%) had a mean varus deformity of 169.4° (153° to 178°) and 17 limbs had a mean valgus deformity 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° of 21.1mm 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 lateral radiographs, 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 mm postoperatively. At a mean follow up 28 months (14- 48 months) the knee, function, and pain scores improved by 61, 48, and 28 points, respectively and there 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 and take appropriate measures in terms of resection and releases to correct it satisfactorily. Computer assisted TKA helps to achieve excellent deformity correction, limb alignment, gap balancing and function in patients with recurvatum deformity by accurately quantifying and helping to modify the amount of bone cuts and titrate soft tissue release.