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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

Head/neck morphology of the three types of synthetic femurs used in this study. Anterior (a), top (b), and posterior (c) view: normal configuration, osteophytes, slipped epiphysis (right to left).
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Fig2: Head/neck morphology of the three types of synthetic femurs used in this study. Anterior (a), top (b), and posterior (c) view: normal configuration, osteophytes, slipped epiphysis (right to left).

Mentions: Three morphologically different types of left Sawbone® femurs (“physiological” #1100, “osteoarthritis” #1197, “slipped capital epiphysis (SCFE)” #1161, Figure 2) were used for this study. The proximal halves of the specimens were painted with radiopaque colour (Genius Pro, Germany, Cosefeld) in order to allow an enhanced radiographic evaluation before and after intervention. During intervention the femurs were mounted onto a clamp (Sawbones®: universal bone clamp #1605) and positioned to mimic the intraoperative situation (Figure 3). Furthermore, the femurs were covered by drapes in a standardized manner only leaving the proximal medial part of the specimens (including the lesser trochanter, the piriformis fossa, the femoral neck, and the femoral head) visible to the surgeon, thereby avoiding the risk of orientation along the femoral diaphysis. The surgeons followed the manufacturers’ guidelines for HR and CAS.Figure 2


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)

Head/neck morphology of the three types of synthetic femurs used in this study. Anterior (a), top (b), and posterior (c) view: normal configuration, osteophytes, slipped epiphysis (right to left).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: Head/neck morphology of the three types of synthetic femurs used in this study. Anterior (a), top (b), and posterior (c) view: normal configuration, osteophytes, slipped epiphysis (right to left).
Mentions: Three morphologically different types of left Sawbone® femurs (“physiological” #1100, “osteoarthritis” #1197, “slipped capital epiphysis (SCFE)” #1161, Figure 2) were used for this study. The proximal halves of the specimens were painted with radiopaque colour (Genius Pro, Germany, Cosefeld) in order to allow an enhanced radiographic evaluation before and after intervention. During intervention the femurs were mounted onto a clamp (Sawbones®: universal bone clamp #1605) and positioned to mimic the intraoperative situation (Figure 3). Furthermore, the femurs were covered by drapes in a standardized manner only leaving the proximal medial part of the specimens (including the lesser trochanter, the piriformis fossa, the femoral neck, and the femoral head) visible to the surgeon, thereby avoiding the risk of orientation along the femoral diaphysis. The surgeons followed the manufacturers’ guidelines for HR and CAS.Figure 2

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