Ivan Jacob1, Jessica Benson2, Kate Shanaghan1, Alejandro Gonzalez Della Valle3. 1. Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA. 2. Intellijoint Surgical Inc., Waterloo, ON, Canada. 3. Department of Orthopaedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY, 10021, USA. gonzaleza@hss.edu.
Abstract
INTRODUCTION: Computer-assisted surgery (CAS) relying on registration of the anterior pelvic plane (APP) allows precise acetabular component placement. We determined the variability of cup placement in patients who underwent THA with and without the use of CAS that does not rely on the registration of APP. METHODS: Fifty-one patients who underwent staged-bilateral THAs, one without CAS (control), and a subsequent one with CAS (study group), were included. Acetabular inclination and anteversion were measured on standardized post-operative radiographs. Variance in cup position and Lewinnek's zone proportionality were compared between the groups. Multiple regressions were performed to identify factors affecting variability in acetabular component placement. RESULTS: The mean inclination for the control and study group was 42.7° (SD 4.5) and 42.5° (SD 2.9), respectively. The inclination variance was 20.5° and 8.2° respectively (p = < 0.001). Cup inclination was more consistent in the study than in the control group (deviation from the mean: 2.3° vs. 3.8°, p < 0.001). The mean anteversion for the control and the study group was 25.5° (SD 7.4) and 26.8° (SD 4.3), respectively. The anteversion variance was 54.2° and 18.2° respectively (p = <0.001). Consistency in cup anteversion was significantly improved with CAS (deviation from the mean: 3.4° vs. 5.8°; p = 0.002). Lewinnek's zone proportionality was not affected by the use of CAS. In the linear regression analysis, CAS significantly increased consistency in cup inclination (p = 0.01). Patient's factors including BMI and laterality affected consistency of cup placement. CONCLUSION: CAS without referencing the APP allows a more consistent orientation of the acetabular component when compared to freehand placement.
INTRODUCTION: Computer-assisted surgery (CAS) relying on registration of the anterior pelvic plane (APP) allows precise acetabular component placement. We determined the variability of cup placement in patients who underwent THA with and without the use of CAS that does not rely on the registration of APP. METHODS: Fifty-one patients who underwent staged-bilateral THAs, one without CAS (control), and a subsequent one with CAS (study group), were included. Acetabular inclination and anteversion were measured on standardized post-operative radiographs. Variance in cup position and Lewinnek's zone proportionality were compared between the groups. Multiple regressions were performed to identify factors affecting variability in acetabular component placement. RESULTS: The mean inclination for the control and study group was 42.7° (SD 4.5) and 42.5° (SD 2.9), respectively. The inclination variance was 20.5° and 8.2° respectively (p = < 0.001). Cup inclination was more consistent in the study than in the control group (deviation from the mean: 2.3° vs. 3.8°, p < 0.001). The mean anteversion for the control and the study group was 25.5° (SD 7.4) and 26.8° (SD 4.3), respectively. The anteversion variance was 54.2° and 18.2° respectively (p = <0.001). Consistency in cup anteversion was significantly improved with CAS (deviation from the mean: 3.4° vs. 5.8°; p = 0.002). Lewinnek's zone proportionality was not affected by the use of CAS. In the linear regression analysis, CAS significantly increased consistency in cup inclination (p = 0.01). Patient's factors including BMI and laterality affected consistency of cup placement. CONCLUSION: CAS without referencing the APP allows a more consistent orientation of the acetabular component when compared to freehand placement.
Entities:
Keywords:
Anterior pelvic plane; Computer-assisted surgery; Cup position; Total hip arthroplasty
Authors: Eli Kamara; Jonathon Robinson; Marcel A Bas; Jose A Rodriguez; Matthew S Hepinstall Journal: J Arthroplasty Date: 2016-06-29 Impact factor: 4.757
Authors: Alejando Gonzalez Della Valle; Kate Shanaghan; Jessica R Benson; Kaitlin Carroll; Michael Cross; Alexander McLawhorn; Peter K Sculco Journal: Int Orthop Date: 2018-09-21 Impact factor: 3.075