BACKGROUND: Femoral stem anteversion during hip arthroplasty is generally estimated by eye intraoperatively and has proven to be different from targeted values. This study aims to determine the accuracy of a novel technique using a digital protractor and a spirit level to improve surgeons' estimation of stem anteversion. METHODS: A prospective non-randomized study was conducted among 93 patients with femoral neck fracture who underwent cemented hemiarthroplasty via posterolateral approach. In the control group (N=62), five experienced surgeons assessed stem anteversion related to the posterior femoral condylar plane using visual estimation with a target angle of 15°-25°. In the study group (N=31), another two surgeons assessed stem anteversion with the same target angle by placing a digital protractor on the femoral stem inserter handle while the assistant held the leg in the truly vertical position, verified by a spirit level that was attached to the shin with cable ties. Stem anteversion was measured blind, postoperatively, on 2D-CT and compared with the intraoperative results. RESULTS: The mean postoperative anteversion was 22.4° (-4.2° to 51.3°, SD 11.1°) in the control group and 23.0° (16.0° to 29.9°, SD 3.6°) in the study group (P=0.810). The study group had more stems positioned in 15°-25° anteversion (71.0% vs 32.3%, P=0.001) and the mean absolute value of surgeon error was -0.2° (-5.4° to 7.0°, SD 3.0°). Twenty-eight stems of the study group (90.3%) had an error within 5°. Surgeon overestimation >5° was found in 1 hip (3.2%) and underestimation >5° was found in 2 hips (6.4%). CONCLUSION: Using a digital protractor and a spirit level was reliable with high accuracy and precision to improve the intraoperative estimation of cemented stem anteversion.
BACKGROUND: Femoral stem anteversion during hip arthroplasty is generally estimated by eye intraoperatively and has proven to be different from targeted values. This study aims to determine the accuracy of a novel technique using a digital protractor and a spirit level to improve surgeons' estimation of stem anteversion. METHODS: A prospective non-randomized study was conducted among 93 patients with femoral neck fracture who underwent cemented hemiarthroplasty via posterolateral approach. In the control group (N=62), five experienced surgeons assessed stem anteversion related to the posterior femoral condylar plane using visual estimation with a target angle of 15°-25°. In the study group (N=31), another two surgeons assessed stem anteversion with the same target angle by placing a digital protractor on the femoral stem inserter handle while the assistant held the leg in the truly vertical position, verified by a spirit level that was attached to the shin with cable ties. Stem anteversion was measured blind, postoperatively, on 2D-CT and compared with the intraoperative results. RESULTS: The mean postoperative anteversion was 22.4° (-4.2° to 51.3°, SD 11.1°) in the control group and 23.0° (16.0° to 29.9°, SD 3.6°) in the study group (P=0.810). The study group had more stems positioned in 15°-25° anteversion (71.0% vs 32.3%, P=0.001) and the mean absolute value of surgeon error was -0.2° (-5.4° to 7.0°, SD 3.0°). Twenty-eight stems of the study group (90.3%) had an error within 5°. Surgeon overestimation >5° was found in 1 hip (3.2%) and underestimation >5° was found in 2 hips (6.4%). CONCLUSION: Using a digital protractor and a spirit level was reliable with high accuracy and precision to improve the intraoperative estimation of cemented stem anteversion.
Entities:
Keywords:
Digital protractor; Femoral stem anteversion; Hip arthroplasty; Spirit level
Authors: Robert A Siston; Aaron C Daub; Nicholas J Giori; Stuart B Goodman; Scott L Delp Journal: Clin Orthop Relat Res Date: 2005-10 Impact factor: 4.176
Authors: Gunnar B Flugsrud; Lars Nordsletten; Birgitte Espehaug; Leif I Havelin; Haakon E Meyer Journal: Acta Orthop Date: 2007-02 Impact factor: 3.717