Thermal Effects during Bone Preparation and Insertion of Osseointegrated Transfemoral Implants

Abstract

Background: The preparation of bone for the insertion of an osseointegrated transfemoral implant and the insertion process are performed at very low speeds in order to avoid thermal damages to bone tissue which may potentially jeopardize implant stability. The aim of this study was to quantify the temperature increase in the femur at different sites and insertion depths, relative to the final implant position during the stepwise implantation procedure. Methods: The procedure for installation of the osseointegrated implant was performed on 24 femoral specimens. In one specimen of each pair, the surgery was performed at the clinically practiced speed, while the speed was doubled in the contralateral specimen. Six 0.075 mm K fine gauge thermocouples (RS Components, Sorby, UK) were inserted into the specimen at a distance of 0.5 mm from the final implant surface, and six were inserted at a distance of 1.0 mm. Results: Drilling caused a temperature increase of <2.5 °C and was not statistically significantly different for most drill sizes (0.002 < p < 0.845). The mean increase in temperature during thread tapping and implant insertion was <5.0 °C, whereas the speed had an effect on the temperature increase during thread tapping. Conclusions: Drilling is the most time-consuming part of the surgery. Doubling the clinically practiced speed did not generate more heat during this step, suggesting the speed and thus the time- and cost-effectiveness of the procedure could be increased. The frequent withdrawal of the instruments and removal of the bone chips is beneficial to prevent temperature peaks, especially during thread tapping.

Patient-Specific Guides for Accurate and Precise Positioning of Osseointegrated Implants in Transfemoral Amputations: A Proof-of-Concept In Vitro Study

“…A total of 20 specimens of human femoral specimens (10 female and 10 male or 9 left and 11 right), obtained from 12 donors to the Centre for Anatomy and Cell Biology, Medical University of Vienna were used ( Table 1 ). The specimens belonged to a larger population that was used to assess the thermal effects during bone preparation and insertion of osseointegrated transfemoral implants [ 12 ]. The donors had provided written consent for their bodies to be used for research and education.…”

“…3-Matic Research 13.0 (Materialise NV, Leuven, Belgium) was used to design the specimen-specific positioning guides and experimental setup. The complete setup has been described previously [ 12 ]. Its most relevant parts are illustrated in Figure 2 .…”

“…The surgical procedure has been described in detail previously [ 12 ]. In short, a single senior surgeon (GMH) performed all surgical steps, including drilling, thread tapping and fixture insertion.…”

The application of impantable sensors in the musculoskeletal system: a review

“…Thermistors represent the most common application of thermal sensors, where the resistance varies in response to temperature changes ( Ramanathan and Danielsson, 2001 ). Benca et al (2021) used thermal sensors to measure the amount of heat generated during drilling. The result showed that drilling caused a temperature increase of <2.5°C and the mean increase in temperature during thread tapping and implant insertion was <5.0°C.…”

Implants with Sensing Capabilities

“…Its use offers economical and simple measurement of a wide range of temperatures. 242 As regards implants, thermoelectric sensors can be integrated with dental 223 and transfemoral 243 implants for detecting inflammation and infection. However, both sensor types are associated with challenges such as efficient localized monitoring, flexible sensor design, elimination of additional calibration and long-term safety, 223 which still need to be addressed.…”