Robotic-Assisted THA Can Achieve Precise Cup Positioning Even in Severe Developmental Dysplasia of Hip

3 pages•Published: September 25, 2020

Abstract

Introduction
We hypothesize robotic-assisted THA can achieve precise cup positioning. The aim of this study is to figure out the accuracy of cup placement of severe DDH cases by using robotic-assisted THA
Methods
This was a prospective cohort study. The study analyzed a consecutive series of 53 hips with robotic-assisted THA between Aug 2018 and Sep 2019. Fifteen patients were DDH cases, and classified Crowe type II- 7 patients, type III- 7 patients, and type IV- 1 patient. All patients underwent robotic assisted-THA (MAKO Rio Robot, Ft. Lauderdale, FL) for osteoarthritis via the Hardinge or posterior approach in the lateral position. TTo analyze the accuracy of intraoperative navigation records for cup inclination and anteversion, we compared the intraoperative cup angles using the navigation records with the postoperative angles using postoperative CT data.
Results
Reproducibility of robotic-assisted THA for preoperative plan
In non DDH cases, the average measurement absolute error (postoperative CT-preoperative target) was 1.9 ± 2.1° (inclination) and 2.0 ± 2.5° (anteversion) (Figure 1). In DDH cases, the average measurement absolute error (postoperative CT- preoperative target) was 2.2 ± 3.1° (inclination) and 2.6 ± 2.4° (anteversion) (Figure 1). There were no differences of the average measurement absolute error between DDH and non DDH cases.
Accuracy of navigation record for cup inclination and anteversion angles
In non DDH cases, the average measurement absolute error (postoperative CT-navigation record) was 2.3 ± 1.9° (inclination) and 2.2 ± 1.5° (anteversion) (Figure 1). In DDH cases, the average measurement absolute error (postoperative CT-navigation record) was 2.0 ± 2.5° (inclination) and 2.3 ± 2.7° (anteversion) (Figure 1). There were no differences of the average measurement absolute error between DDH and non DDH cases. Scatter plots demonstrated the measurement error of both inclination and anteversion within 5° was 89.5% in non DDH cases (Figure 2a) and 80% in DDH cases (Figure 2b).
Discussion
In this study, we demonstrated that no differences of the average measurement absolute navigation record error or the absolute difference between target angle and postoperative cup alignment were found between severe DDH and non-DDH cases. Our results indicate that this robotic-assisted system has high accuracy for cup placement even in severe DDH case.

Keyphrases: 3D alignment, Accuracy, DDH, Navigation, Robotic-assisted total hip arthroplasty

In: Ferdinando Rodriguez Y Baena and Fabio Tatti (editors). CAOS 2020. The 20th Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery, vol 4, pages 108--110

Links:	https://easychair.org/publications/paper/gNNP
	https://doi.org/10.29007/c5p2