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Effect of surgical experience on imageless computer-assisted femoral component positioning in hip resurfacing--a preclinical study.

Stiehler M, Goronzy J, Kirschner S, Hartmann A, Schäfer T, Günther KP - Eur. J. Med. Res. (2015)

Bottom Line: The incidence of either varus or valgus SSA deviations exceeding 5° were 1/27 for CAS and 15/27 for the conventional method, respectively (P < 0.001), corresponding to a reduction by 97%.Using CAS, the rate of notching was reduced by 100%.The accuracy of femoral HR component orientation is significantly increased by use of CAS regardless of the surgeon's level of experience in our preclinical study.

View Article: PubMed Central - PubMed

Affiliation: University Centre for Orthopaedics & Trauma Surgery, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstr. 74, Building 29, D-01307, Dresden, Germany. maik.stiehler@uniklinikum-dresden.de.

ABSTRACT

Background: The clinical outcome of hip resurfacing (HR) as a demanding surgical technique associated with a substantial learning curve depends on the position of the femoral component. The aim of the study was to investigate the effects of the level of surgical experience on computer-assisted imageless navigation concerning precision of femoral component positioning, notching, and oversizing rate, as well as operative time.

Methods: Three surgeons with different levels of experience in both HR and computer-assisted surgery (CAS) prepared the femoral heads of 54 synthetic femurs using the Durom(TM) Hip Resurfacing (Zimmer, Warsaw, IN, USA) system. Each surgeon prepared a total of 18 proximal femurs using the Navitrack® system (ORTHOsoft Inc., Montreal, Canada) or the conventional free-hand Durom(TM) K-wire positioning jig. The differences between planned and postoperative stem shaft angle (SSA) and anteversion angle in standardized x-rays were measured and the operative time, not including the time for calibrating the CAS-system, was documented. Notching was evaluated by the three surgeons in a randomized manner. Oversizing was determined by the difference of the preoperative determined cap and the cap size advised by the CAS-system.

Results: CAS significantly reduced the overall mean deviation between planned and postoperative SSA in comparison with the conventional procedure (mean ± SD, 1 ± 1.7° vs. 7.4 ± 4.4°, P < 0.01) regardless of the surgeon's level of experience. The incidence of either varus or valgus SSA deviations exceeding 5° were 1/27 for CAS and 15/27 for the conventional method, respectively (P < 0.001), corresponding to a reduction by 97%. Using CAS, the rate of notching was reduced by 100%.

Conclusions: The accuracy of femoral HR component orientation is significantly increased by use of CAS regardless of the surgeon's level of experience in our preclinical study. Thus, imageless computer-assisted navigation can be a valuable tool to improve implant positioning in HR for surgeons at any stage of their learning curve.

No MeSH data available.


Related in: MedlinePlus

Notching events in the superior (a) and posterior (b) quadrant (arrows).
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Fig6: Notching events in the superior (a) and posterior (b) quadrant (arrows).

Mentions: As presented in Table 3, notching was reduced by 100% in the CAS group as compared to the conventional group (n = 0, 0% vs. n = 8, 29.6%; P = 0.01). Superior (Figure 6a) notching occurred in 5 (18.5%), whereas posterior, inferior (Figure 6b), and anterior-superior notching was observed in 1 (3.7%) case each. Surgeon A generated most notching events (n = 5, 55.6%), followed by surgeon B (n = 2, 22.2%), and surgeon C (n = 1, 11.1%). A regression analysis demonstrated that only CAS (P <0.01) and the most experienced surgeon (P <0.01) reduced the rate of notching events. Notably, in all operations, the navigation software issued warnings for at least one quadrant when using the planned prosthesis size (Table 4). The software generally recommended a 7 ± 3.6 mm larger femoral component than was planned (Table 5). Surgeon A achieved the least average oversizing recommendation (4.22 ± 1.2 mm) followed by surgeon C (6.9 ± 2.3 mm) and surgeon B (10.0 ± 4.0 mm) as compared to the planned preoperative femoral component size. For the SCFE synthetic femur, the component size recommended by the software was 9.8 ± 4.2 mm larger as compared with the planned size. Similarly, for both other femur types (physiological 5.8 ± 2.3 mm and osteophytes 5.6 ± 2.4 mm) smaller prosthesis sizes were recommended by the CAS system.Figure 6


Effect of surgical experience on imageless computer-assisted femoral component positioning in hip resurfacing--a preclinical study.

Stiehler M, Goronzy J, Kirschner S, Hartmann A, Schäfer T, Günther KP - Eur. J. Med. Res. (2015)

Notching events in the superior (a) and posterior (b) quadrant (arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4355522&req=5

Fig6: Notching events in the superior (a) and posterior (b) quadrant (arrows).
Mentions: As presented in Table 3, notching was reduced by 100% in the CAS group as compared to the conventional group (n = 0, 0% vs. n = 8, 29.6%; P = 0.01). Superior (Figure 6a) notching occurred in 5 (18.5%), whereas posterior, inferior (Figure 6b), and anterior-superior notching was observed in 1 (3.7%) case each. Surgeon A generated most notching events (n = 5, 55.6%), followed by surgeon B (n = 2, 22.2%), and surgeon C (n = 1, 11.1%). A regression analysis demonstrated that only CAS (P <0.01) and the most experienced surgeon (P <0.01) reduced the rate of notching events. Notably, in all operations, the navigation software issued warnings for at least one quadrant when using the planned prosthesis size (Table 4). The software generally recommended a 7 ± 3.6 mm larger femoral component than was planned (Table 5). Surgeon A achieved the least average oversizing recommendation (4.22 ± 1.2 mm) followed by surgeon C (6.9 ± 2.3 mm) and surgeon B (10.0 ± 4.0 mm) as compared to the planned preoperative femoral component size. For the SCFE synthetic femur, the component size recommended by the software was 9.8 ± 4.2 mm larger as compared with the planned size. Similarly, for both other femur types (physiological 5.8 ± 2.3 mm and osteophytes 5.6 ± 2.4 mm) smaller prosthesis sizes were recommended by the CAS system.Figure 6

Bottom Line: The incidence of either varus or valgus SSA deviations exceeding 5° were 1/27 for CAS and 15/27 for the conventional method, respectively (P < 0.001), corresponding to a reduction by 97%.Using CAS, the rate of notching was reduced by 100%.The accuracy of femoral HR component orientation is significantly increased by use of CAS regardless of the surgeon's level of experience in our preclinical study.

View Article: PubMed Central - PubMed

Affiliation: University Centre for Orthopaedics & Trauma Surgery, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstr. 74, Building 29, D-01307, Dresden, Germany. maik.stiehler@uniklinikum-dresden.de.

ABSTRACT

Background: The clinical outcome of hip resurfacing (HR) as a demanding surgical technique associated with a substantial learning curve depends on the position of the femoral component. The aim of the study was to investigate the effects of the level of surgical experience on computer-assisted imageless navigation concerning precision of femoral component positioning, notching, and oversizing rate, as well as operative time.

Methods: Three surgeons with different levels of experience in both HR and computer-assisted surgery (CAS) prepared the femoral heads of 54 synthetic femurs using the Durom(TM) Hip Resurfacing (Zimmer, Warsaw, IN, USA) system. Each surgeon prepared a total of 18 proximal femurs using the Navitrack® system (ORTHOsoft Inc., Montreal, Canada) or the conventional free-hand Durom(TM) K-wire positioning jig. The differences between planned and postoperative stem shaft angle (SSA) and anteversion angle in standardized x-rays were measured and the operative time, not including the time for calibrating the CAS-system, was documented. Notching was evaluated by the three surgeons in a randomized manner. Oversizing was determined by the difference of the preoperative determined cap and the cap size advised by the CAS-system.

Results: CAS significantly reduced the overall mean deviation between planned and postoperative SSA in comparison with the conventional procedure (mean ± SD, 1 ± 1.7° vs. 7.4 ± 4.4°, P < 0.01) regardless of the surgeon's level of experience. The incidence of either varus or valgus SSA deviations exceeding 5° were 1/27 for CAS and 15/27 for the conventional method, respectively (P < 0.001), corresponding to a reduction by 97%. Using CAS, the rate of notching was reduced by 100%.

Conclusions: The accuracy of femoral HR component orientation is significantly increased by use of CAS regardless of the surgeon's level of experience in our preclinical study. Thus, imageless computer-assisted navigation can be a valuable tool to improve implant positioning in HR for surgeons at any stage of their learning curve.

No MeSH data available.


Related in: MedlinePlus