Paper #56 - ISHA Annual Scientific Meeting 2016

Accuracy of Navigated Cam Resection in Femoroacetabular Impingement: a Randomized Controlled Trial.

Jan Van Houcke, MD, Gent BELGIUM
Vikas Khanduja, MA (Cantab), MSc, FRCS, FRCS (Tr & Orth), Cambridge, Cambridgeshire UNITED KINGDOM
Louis Sueys, Gent BELGIUM
Klaas Lanszweert, Gent BELGIUM
Peter Krekel, Delft NETHERLANDS
Christophe Pattyn, MD, PhD, Gent BELGIUM
Emmanuel Audenaert, MD, PhD, Ghent BELGIUM

Ghent University Hospital, Ghent, BELGIUM

FDA Status Not Applicable

Summary: Under-resection of the cam lesion occurred mainly at the lateral portion of the cam but the overall risk for incomplete resection was significantly smaller in the computer-assisted group.

Abstract:
Introduction: With the popularization of arthroscopic osteochondroplasty in femoroacetabular impingement (FAI), the number of revisions in hip preservation surgery has steadily increased. Recent studies coin the revision rate to around 5% with the main cause being an incomplete bony resection in up to 80% of these cases. Residual bony FAI after primary hip arthroscopy has been reported to be as high as 60% in isolated pincer lesions. Since a complete resection is paramount in obtaining a good functional outcome, we introduced a computer assisted control of the resection during arthroscopic FAI surgery. The aim of this study was to compare the cam resection accuracy in navigated surgeries compared to the conventional fluoroscopically guided surgeries. Secondly the increase in simulated hip range of motion was evaluated in both groups.
Materials and methods: Prospectively, 29 male cam-type FAI patients were recruited for arthroscopic cam osteochondroplasty. A computer-based blocked randomization was performed in each case resulting in a total of 14 conventional fluoroscopically guided surgeries and 15 navigated surgeries. A preoperative CT scan for alpha angle measurements, range of motion simulation and determination of a 3D surgical resection plan was performed in all patients (Articulis, Clinical Graphics, The Netherlands). In the navigated surgery group, this resection plan was matched to the patient with an image based registration procedure at the beginning of the surgery. By means of a navigated pointer the arthroscopic resection could be verified intra-operatively. All patients underwent MRI imaging 12 weeks postoperatively to evaluate kinematics and resection results by means of clockwise alpha angle.
Results: Significant differences were obtained in the correction of the 12 o’clock alpha angle as well as in post-operative simulated range of internal rotation at 90 degrees of flexion (p < 0.05). The alpha angle correction at the 1,2 and 3 o’ clock position did not differ significantly between the 2 groups.
Conclusion: Under-resection of the cam lesion occurred mainly at the lateral portion of the cam but the overall risk for incomplete resection was significantly smaller in the computer-assisted group.

Note: At the time of abstract submission all 29 patients included in the study had underwent surgery. However, some patients still have to undergo postoperative MRI scans. We expect this to be finished by the 1st of July.