DOS Kongressen 2014 ·
195
Validation of intraoperative reported angle
measurements in periactabular osteotomy
Sepp de Raedt, Inger Mechlenburg, Maiken Stilling, Marleen de Bruijne, Lone
Rømer, Kjeld Søballe
Orthopaedic Research Unit, Aarhus University Hospital; BIGR/DIKU, Erasmus
MC Rotterdam/University of Copenhagen; Department of Radiology, Aarhus
University Hospital
Background:
Periactabular osteotomy (PAO) has become the treatment of
choice for patients with developmental hip dysplasia. However, it is a technically
demanding procedure and achieving an optimal correction can be difficult due
to the lack of three-dimensional (3D) feedback. The biomechanical guidance
system (BGS) provides the surgeon with live 3D feedback.
Purpose / Aim of Study:
To validate measurements obtained with the BGS
against manual measurements.
Materials and Methods:
Patients underwent pre- and post-operative CT
imaging. Manual center-edge (CE), acetabular index (AI), acetabular antever-
sion (AcAV), posterior acetabular sector (PASA) and anterior acetabular sector
(AASA) angle measurements were performed. The lunate surface was manually
delineated and surgical planning was performed. Initial automatic angle mea-
surements were recorded. After the acetabular fragment was repositioned and
fixated, the BGS was used to obtain the final angle measurements. The differ-
ence between the manual and the BGS reported angle measurements were ana-
lyzed by statistical analysis. We report the concordance correlation coefficient
(CCC), average difference, and the 95% limits of agreement (LOA).
Findings / Results:
Initial results for the first five patients included were: CE
angle: CCC: 0.93, Avg. Diff.: 0.40, 95% LOA: -4.52;5.31. AI angle: CCC: 0.98,
Avg. Diff.: 0.17, 95% LOA: -2.59;2.94. AcAV angle: CCC: 0.96, Avg. Diff.: 0.68,
95% LOA: -2.30;3.66. PASA angle: CCC: 0.92, Avg. Diff.: 0.82, 95% LOA:
-4.26;5.90. AASA angle: CCC: 0.98, Avg. Diff.: 0.03, 95% LOA: -4.63;4.69.
Conclusions:
Initial results show a good agreement between manual and BGS
reported angles and are within the variation expected from intra-rater variabili-
ty. With further development and validation, the system may become a valuable
tool to help the surgeon achieve the optimal correction for each patient.
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