To validate a small, easy to use and cost-effective augmented marker-based hybrid navigation system for peri-acetabular osteotomy [PAO] surgery. A cadaver study including 3 pelvises (6 hip joints) undergoing navigated PAO was performed. Inclination and anteversion of two navigation systems for PAO were compared during acetabular reorientation. The hybrid system consists of a tracking unit which is placed on the patient's pelvis and an augmented marker which is attached to the patient's acetabular fragment. The tracking unit sends a video stream of the augmented marker to the host computer. Simultaneously, the augmented marker sends orientation output from an integrated inertial measurement unit (IMU) to the host computer. The host computer then computes the pose of the augmented marker and uses it (if visible) to compute acetabular orientation. If the marker is not visible, the output from the IMU is used to update the orientation. The second system served as ground truth and is a previously developed and validated optical tracking-based navigation system.Purpose
Methods
A new anterior intrapelvic approach for the surgical
management of displaced acetabular fractures involving predominantly
the anterior column and the quadrilateral plate is described. In
order to establish five ‘windows’ for instrumentation, the extraperitoneal
space is entered along the lateral border of the rectus abdominis
muscle. This is the so-called ‘Pararectus’ approach. The feasibility
of safe dissection and optimal instrumentation of the pelvis was
assessed in five cadavers (ten hemipelves) before implementation
in a series of 20 patients with a mean age of 59 years (17 to 90),
of whom 17 were male. The clinical evaluation was undertaken between
December 2009 and December 2010. The quality of reduction was assessed
with post-operative CT scans and the occurrence of intra-operative
complications was noted. In the treatment of acetabular fractures predominantly involving
the anterior column and the quadrilateral plate, the Pararectus
approach allowed anatomical restoration with minimal morbidity related
to the surgical access.