TY - CONF

T1 - Acetabular QCT in Total Hip Arthroplasty - a reliability study using porcine hips

AU - Mussmann, Bo Redder

AU - Overgaard, Soren

AU - Torfing, Trine

AU - Bøgehøj, Morten

AU - Andersen, Poul Erik

PY - 2017/1/26

Y1 - 2017/1/26

N2 - Introduction Periprosthetic bone loss is considered a predictor of aseptic loosening of the acetabular component in total hip arthroplasty. However, no studies have shown this association. This may be explained by the limitations of imaging methods previously used. Dual energy CT (DECT) has previously shown better delineation of the interface between bone and prosthesis and may be beneficial in quantitative analysis of bone loss close to the implant as compared to single energy computed tomography (SECT). The purpose of this porcine ex-vivo study was to test the intra-observer agreement and reliability of bone mineral density measurements (BMD) in close proximity of the acetabular cup using SECT and DECT images and 3D segmentation software. Materials and methods 22 acetabular cups (12 cemented, 10 un-cemented) were inserted in porcine hip specimens ex vivo. A femoral stem was attached to each specimen and imaging was performed with SECT and DECT. The specimens were repositioned and scans repeated to obtain double measurements. For each scan BMD was measured in a hemispherical volume around the acetabular cup using in-house segmentation software. Results In the uncemented concept mean BMD difference between the double measurements in SECT was 8 mg/cm3 (p=0.64) and 2 mg/cm3 in DECT (p=0.6). In the cemented concept the differences were 33 mg/cm3 (p=0.054) and 11 mg/cm3 (p=0.014), respectively. ICC was >0.90 regardless of scan mode and cup type. In both cup types the Bland-Altman limits of agreement were wider in SECT (uncemented: -95 to 111; cemented: -86 to 153) compared with DECT (uncemented: -28 to 23; cemented: -21 to 44). Conclusion There were no statistically significant reliability differences between SECT and DECT, but results suggest that the agreement of DECT is better than that of SECT, and both scan modes perform better in the un-cemented concept compared with the cemented concept.

AB - Introduction Periprosthetic bone loss is considered a predictor of aseptic loosening of the acetabular component in total hip arthroplasty. However, no studies have shown this association. This may be explained by the limitations of imaging methods previously used. Dual energy CT (DECT) has previously shown better delineation of the interface between bone and prosthesis and may be beneficial in quantitative analysis of bone loss close to the implant as compared to single energy computed tomography (SECT). The purpose of this porcine ex-vivo study was to test the intra-observer agreement and reliability of bone mineral density measurements (BMD) in close proximity of the acetabular cup using SECT and DECT images and 3D segmentation software. Materials and methods 22 acetabular cups (12 cemented, 10 un-cemented) were inserted in porcine hip specimens ex vivo. A femoral stem was attached to each specimen and imaging was performed with SECT and DECT. The specimens were repositioned and scans repeated to obtain double measurements. For each scan BMD was measured in a hemispherical volume around the acetabular cup using in-house segmentation software. Results In the uncemented concept mean BMD difference between the double measurements in SECT was 8 mg/cm3 (p=0.64) and 2 mg/cm3 in DECT (p=0.6). In the cemented concept the differences were 33 mg/cm3 (p=0.054) and 11 mg/cm3 (p=0.014), respectively. ICC was >0.90 regardless of scan mode and cup type. In both cup types the Bland-Altman limits of agreement were wider in SECT (uncemented: -95 to 111; cemented: -86 to 153) compared with DECT (uncemented: -28 to 23; cemented: -21 to 44). Conclusion There were no statistically significant reliability differences between SECT and DECT, but results suggest that the agreement of DECT is better than that of SECT, and both scan modes perform better in the un-cemented concept compared with the cemented concept.

M3 - Poster

Y2 - 25 January 2017 through 27 January 2017

ER -