Patient-specific cruciate-retaining total knee replacement with individualized implants and instruments (iTotal™ CR G2).

Abstract

Treatment of tricompartimental osteoarthritis (OA) using customized instruments and implants for cruciate-retaining total knee arthroplasty. Use of patient-specific instruments and implants (ConforMIS iTotalTM CR G2) together with a 3D-planning protocol (iView®). Retropatellar resurfacing is optional. Symptomatic tricompartmental OA of the knee (Kellgren-Lawrence stageIV) with preserved posterior cruciate ligament (PCL) after unsuccessful conservative or joint-preserving surgical treatment. Knee ligament instabilities of the posterior cruciate or collateral ligaments. Infection. Relative contraindication: knee deformities >15° (varus, valgus, flexion); prior partial knee replacement. Midline or parapatellar medial skin incision, medial arthrotomy; distal femoral resection with patient-specific cutting block; tibial resection using either acutting jig for the anatomic slope or afixed 5° slope. Balancing the knee in extension and flexion gap using patient-specific spacer.The final tibial preparation achieved with gap-balanced placement of the femoral cutting jigs. Kinematic testing using anatomic trial components. Final implant components are cemented in extension. Wound layers are sutured. Drainage is optional. Sterile wound dressing; compressive bandage. No limitation of the active and passive range of motion. Optional partial weight bearing during the first 2weeks, then transition to full weight bearing. Follow-up directly after surgery, at 12 and 52weeks, then every 1-2years. Overall 60patients with tricompartmental knee OA and preserved PCL were treated. Mean age was 66 (range 45-76) years. Minimum follow-up was 12months. There was 1septic revision after alow-grade infection, 1reoperation to replace the patellar due to patellar osteoarthritis and 3manipulations under anesthesia (MUAs) to increase range of motion. Radiographic analyses demonstrated an ideal implant fit with less than 2 mm subsidence or overhang. The WOMAC score improved from 154.8points preoperatively to 83.5points at 1 year and 59.3points at 2years postoperatively. The EuroQol-5D Score also improved from 11.1points preoperatively to 7.7points at 1year postoperatively.