Shaw reports that he uses Materialise OrthoView software for all his cases as he finds “pre-operative planning of Primary THR using Materialise OrthoView on scaled x-rays is accurate and helpful.” He also performed a comparison to show his success with the pre-operative templating, demonstrating the following:
- Exact hip stem offset size matches in 100 percent of cases
- Exact hip stem matches in 85 percent of cases
- Exact acetabular size matches in 87 percent of cases
“The resulting images and reports were saved back to the PACS and a copy of the templated sizes printed on what Dr. Shaw refers to as a ‘shopping list’ or list of prostheses required,” states the Materialise team in a recent blog. “This list was used to collect the prostheses most likely to be needed for the surgery that day. In some cases, two optional sizes were recorded when the templating was between two sizes. A clinical decision was then taken at the time of surgery to identify the best option for the patient.
“The component sizes recorded were Stem Size, Stem Offset, Neck length for the 28 mm head, acetabular size and cement restrictor plug size. The neck length and plug sizes were roughly templated and usually two sizes were recorded on the shopping list because Dr. Shaw believes that these component sizes are best judged at the time of surgery.”
An analysis was performed at the completion of the study to see how the templates measured up to the actual prosthesis sizes. (See the table below.)
With the templated Exeter Hip stem offset matching in all 39 cases, Shaw said he only felt he had to ‘hedge his bets’ in two of the cases, thus documenting two different possible sizes while he was templating. The results demonstrate 85 percent accuracy with the Exeter Hip stem size. For the remaining 15 percent, the size was off by one. The acetabular sizing was correct 87 percent of the time, with seven cases reporting two options.
“During surgery, if the surgeon finds a component size is different from the plan then careful examination for technical errors should be undertaken, rather than assuming the templating is wrong.” Dr. Shaw explains. “For example, under-reaming of the femur, resulting in an undersized and mal-positioned femoral component is quite a common technical error. This can be identified in this way and avoided.”
Shaw believes templating can offer other benefits too, such as:
- Leg length correction
- Anticipation of issues with bone loss
- Planning for dysplastic acetabulum
Other surgeons can also find the software helpful for trauma and fracture management, limb deformities in pediatric patients, and spinal deformities. If you are interested in finding out more about Materialise OrthoView, or if your company is interested in requesting a trial of the software, contact Materialise here.
Discuss in the OrthoView forum at 3DPB.com.
