9 February 2011 - Study shows 3D planning and patient-specific guides aid in the precise planning and execution of osteotomies around the knee

LEUVEN, Belgium, Feb. 9 /PRNewswire/ - Materialise is proud of its involvement in the successful pilot study conducted by Dr. J. Victor, AZ St Lucas, Brugge, Belgium which evaluated the feasibility of using computer-assisted surgical planning and patient-specific surgical guides in correcting lower limb malalignment. In this study, Materialise's SurgiCase Orthopaedics was used to describe lower limb malalignment and virtually plan multi-planar correction using CT scans. It was proven that planned corrections can be obtained and fixed accurately during surgery with the help of Materialise's patient-specific surgical guides.

Despite recent innovations, lower limb malalignment continues to be corrected using traditional methods and techniques, i.e. relying on 2D plain X-rays and using rulers and protractors, although this can be prone to error and in some cases, inaccurate in multi-planar deformities.Therefore, the aim of this pilot study was to evaluate the feasibility of virtual pre-operative 3D planning and correct execution of osteotomies around the knee with the aid of patient-specific surgical guides.

Eight patients presenting with significant malalignment of the lower limb were included in the study (7 valgus, 1 varus knee). Pre-operative CT scans of the affected limbs and the normal contra-lateral side were obtained and sent to Materialise where 3D models of the patients' anatomy were created. These models made it possible for Dr. Victor to carefully evaluate the three-planar deformity of each patient and identify customized surgical corrections.

After creating the virtual surgical plans with Dr Victor, the Materialise team - in close collaboration with Dr. Victor - continued designing the patient-specific surgical guides used to perform the planar osteotomy and achieve the planned wedge opening and hinge axis orientation. These guides were also used in the drilling of the planned screw holes and thus, determined the position of the plate relative to the bone. Post-operative assessments of the corrections were obtained through AP and Lateral X-rays, and full leg standing X-rays.

The results of the study are promising. All of the patient-specific guides were successfully used during surgery and accurately guided the osteotomy plane and screw holes. The guides fit uniquely onto the patients' bones and it was possible to perform the osteotomies through the guides. The predrilled screw holes matched the locking plates and adequate fixations were obtained. No significant peri-operative complications occurred.

Materialise will be exhibiting at the AAOS 2011 annual meeting in San Diego, CA, Feb. 15-19, booth 1850.

SOURCE Materialise N.V.