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*Email: mhafez@msn.comCurrent techniques rely on conventional instrumentation, which result in the violation ofintramedullary canals and their accuracy is questionable. The repeated use of their numerouspieces may lead to disease transmission and contamination. Navigation techniques still rely onconventional instrumentation and both may overload hospital inventory, sterilization services,surgeons’ learning curve and theatre time.A new technique of using computer assisted preoperative planning to produce patient specifictemplates (cutting blocks) for TKR was previously reported by the first author. The techniquecompletely replaced conventional instruments including intramedullary guides and significantlyreduced operative time and the need for surgical assistants. The previous experimental surgeryon 45 cadaveric and plastic knees showed high accuracy and reproducibility that werecomparable to navigational systems without the use of navigation or computer assisted devicesin the operating room.We report the preliminary clinical results of this technique on patients undergoing TKR. Rapidprototyping technology was used to transfer the CT-based virtual preoperative planning ofpatients into physical femoral and tibial cutting blocks that uniquely matched the geometry ofarticular surfaces and allowed bone cutting as planned. The results on straightforward cases ofTKR showed that the most critical step of this technique was the intraoperative positioning ofthe femoral and tibial templates (cutting blocks) on the distal femur and the proximal tibia. Thetemplates were patient specific and their positioning was based on surface matching with theirrespective bones. Malpositioning would most likely result in errors in bone cutting. However,templates could be easily positioned to match the surface geometry of distal femur andproximal tibia and act as cutting blocks. This patient specific positioning accurately maintainedall required angles in coronal, saggital and transverse planes such as femoral valgus, femoralrotation and tibial posterior sloping as shown in postoperative radiographs. No intramedullaryperforation, pin insertion, tracking or registration was required. All operations were successfullyperformed using the templates without resorting to conventional instrumentation. The operativetime was halved and the procedure could be technically performed without surgical assistance.The technique was also proved to be useful for complex cases of extra-articular deformities. Insuch cases the use of conventional TKR techniques including intramedullary guides would notbe technically possible and has high risk of errors and complications.The patient specific templating (custom made cutting guides) for TKR can be routinely used forboth straightforward and complex cases with extra-articular deformities. It also has the potentialto be used as a training tool, allowing complete planning of surgery with 3-D simulation thatfacilitates identification and correction of errors in real time. It appears that this technique hasseveral advantages over conventional instrumentation technique and is a simple and practicalalternative to navigation and robotic techniques for TKR.Reference:Hafez MA, Chelule KL, Seedhom BB, Sherman KP. Computer-assisted Total KneeArthroplasty Using Patient-Specific Templating. Clin Orthop Relat Res. 2006;444:184-192FiguresFigure 1file:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]