Basic Science
Three-dimensional planning and use of patient-specific guides improve glenoid component position: an in vitro study

https://doi.org/10.1016/j.jse.2014.05.029Get rights and content

Background

Glenoid component positioning is a key factor for success in total shoulder arthroplasty. Three-dimensional (3D) measurements of glenoid retroversion, inclination, and humeral head subluxation are helpful tools for preoperative planning. The purpose of this study was to assess the reliability and precision of a novel surgical method for placing the glenoid component with use of patient-specific templates created by preoperative surgical planning and 3D modeling.

Methods

A preoperative computed tomography examination of cadaveric scapulae (N = 18) was performed. The glenoid implants were virtually placed, and patient-specific guides were created to direct the guide pin into the desired orientation and position in the glenoid. The 3D orientation and position of the guide pin were evaluated by performing a postoperative computed tomography scan for each scapula. The differences between the preoperative planning and the achieved result were analyzed.

Results

The mean error in 3D orientation of the guide pin was 2.39°, the mean entry point position error was 1.05 mm, and the mean inclination angle error was 1.42°. The average error in the version angle was 1.64°. There were no technical difficulties or complications related to use of patient-specific guides for guide pin placement. Quantitative analysis of guide pin positioning demonstrated a good correlation between preoperative planning and the achieved position of the guide pin.

Conclusion

This study demonstrates the reliability and precision of preoperative planning software and patient-specific guides for glenoid component placement in total shoulder arthroplasty.

Section snippets

Materials and methods

Eighteen dry cadaveric scapulae (bilateral specimens from 6 women and 3 men) were obtained from our local anatomy laboratory. The average age of the cadaveric specimens was 78 years. A physical examination excluded any previous disease, fracture, or obvious osteoarthritis. A CT scan of each cadaveric scapula was performed on a Siemens machine (Siemens Healthcare, Malvern, PA, USA). The CT parameters were 140 kV, 180 mAs, and image matrix of 512 × 512. The field of view was adapted with a

Results

The mean differences in pin positioning in comparing planned preoperative guide pin position with the pin placement achieved by use of the patient-specific guides are illustrated in Table I. The mean error in 3D orientation of the pin was 2.39° ± 1.16° (range, 0.53°-4.28°). Average entry point position error was 1.05 ± 0.31 mm (range, 0.60-1.53 mm). Mean inclination angle error was 1.42° ± 1.37° (range, 0.09°-4.55°). The average error in version angle was 1.64° ± 1.01° (range, 0.17°-3.21°).

Discussion

This in vitro study has 2 major findings. First, it demonstrates that the use of a new automated software system enables the surgeon to perform 3D reconstruction and preoperative planning of the scapula based on CT scan images without the help of a technician or an engineer. Second, patient-specific guides manufactured by a 3D printer, based on preoperative planning data, enable the surgeon to reliably and precisely insert a guide pin in the desired glenoid location to correct glenoid

Conclusion

This in vitro study validates the use of the Glenosys software for fully automated 3D reconstruction of the scapula and production of patient-specific guides for glenoid component implantation. It demonstrates the reliability and precision of preoperative planning software and patient-specific guides for glenoid component placement in total shoulder arthroplasty.

Disclaimer

This study was supported by a BPI France development grant A1209018 E. The funds were used to pay the salary for one of the authors (Jean Chaoui).

Jean Chaoui, Gilles Walch, and Pascal Boileau own stock equity in Imascap. The other authors, their immediate families, and any research foundations with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article.

References (25)

Cited by (188)

View all citing articles on Scopus

The Institutional Review Board of the ethical committee of the Hôpital Privé Jean Mermoz and the Centre Orthopédique Santy approved this project (Study 2014-01).

View full text