Femoral Component Alignment with a New Extramedullary Femoral Cutting Guide Technique

Intramedullary (IM) or extramedullary (EM) mechanical guides are used as alignment tools during total knee arthroplasty (TKA) surgery. The EM guide is less invasive; however, the IM mechanical guide is the preferred option since it has shown superior outcomes in several studies. Picture archive and communication system (PACS) images, if available, are extensively used for preoperative planning and intraoperative guidance. This retrospective study compared TKA outcomes using the conventional IM guide and a new EM technique which uses PACS image for preoperative and intraoperative assessment bone resection. To the best of our knowledge, this is the first study with the new EM technique.

The study was performed on 205 knees (190 patients) for TKA from 2011 to 2013. The perioperative blood loss and the postoperative alignment angles were assessed for both mechanical guides. The angles were measured on the radiographs of the patient. The blood loss was assessed by the blood accumulated in the hemovac drain during the surgery and until 3 days after the surgery.

The new EM guide provided similar postoperative alignment as that obtained with the IM guide.

The EM-guided method for femoral bone cutting using PACS films in TKA is as good as the IM method. The additional advantages of less injury to the bone and less fat emboli load to the cardiopulmonary system with the EM method makes it an attractive choice for routine, especially in the elderly and/or simultaneous bilateral, TKA in hospitals without modern computer-assisted navigation systems.