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A novel standardized algorithm using SPECT/CT evaluating unhappy patients after unicondylar knee arthroplasty--a combined analysis of tracer uptake distribution and component position.

Suter B, Testa E, Stämpfli P, Konala P, Rasch H, Friederich NF, Hirschmann MT - BMC Med Imaging (2015)

Bottom Line: For measurement of component position there was strong agreement between the readings of the two observers; the ICC for the orientation of the femoral component was 0.73-1.00 (intra-observer reliability) and 0.91-1.00 (inter-observer reliability).The ICC for the orientation of the tibial component was 0.75-1.00 (intra-observer reliability) and 0.77-1.00 (inter-observer reliability).Using this standardized approach in clinical studies might be helpful in establishing the diagnosis in patients with pain after UKA.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery and Traumatology, Kantonsspital Baselland (Bruderholz, Liestal, Laifen), CH-4101, Bruderholz, Switzerland. basil.suter@unibas.ch.

ABSTRACT

Background: The introduction of a standardized SPECT/CT algorithm including a localization scheme, which allows accurate identification of specific patterns and thresholds of SPECT/CT tracer uptake, could lead to a better understanding of the bone remodeling and specific failure modes of unicondylar knee arthroplasty (UKA). The purpose of the present study was to introduce a novel standardized SPECT/CT algorithm for patients after UKA and evaluate its clinical applicability, usefulness and inter- and intra-observer reliability.

Methods: Tc-HDP-SPECT/CT images of consecutive patients (median age 65, range 48-84 years) with 21 knees after UKA were prospectively evaluated. The tracer activity on SPECT/CT was localized using a specific standardized UKA localization scheme. For tracer uptake analysis (intensity and anatomical distribution pattern) a 3D volumetric quantification method was used. The maximum intensity values were recorded for each anatomical area. In addition, ratios between the respective value in the measured area and the background tracer activity were calculated. The femoral and tibial component position (varus-valgus, flexion-extension, internal and external rotation) was determined in 3D-CT. The inter- and intraobserver reliability of the localization scheme, grading of the tracer activity and component measurements were determined by calculating the intraclass correlation coefficients (ICC).

Results: The localization scheme, grading of the tracer activity and component measurements showed high inter- and intra-observer reliabilities for all regions (tibia, femur and patella). For measurement of component position there was strong agreement between the readings of the two observers; the ICC for the orientation of the femoral component was 0.73-1.00 (intra-observer reliability) and 0.91-1.00 (inter-observer reliability). The ICC for the orientation of the tibial component was 0.75-1.00 (intra-observer reliability) and 0.77-1.00 (inter-observer reliability).

Conclusions: The SPECT/CT algorithm presented combining the mechanical information on UKA component position, alignment and metabolic data is highly reliable and proved to be a valuable, consistent and useful tool for analysing postoperative knees after UKA. Using this standardized approach in clinical studies might be helpful in establishing the diagnosis in patients with pain after UKA.

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Bone tracer uptake quantification of a SPECT/CT in standardized anatomical areas in an asymptomatic patient one year after UKA.
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Fig3: Bone tracer uptake quantification of a SPECT/CT in standardized anatomical areas in an asymptomatic patient one year after UKA.

Mentions: The position of the femoral and tibial UKA components was assessed using a customized software, which is able to reconstruct three-dimensional images from CT data. These 3D models enabled the observer to perform measurements in terms of angles (in degrees) and distances (in mm). The femoral component position (varus-valgus, flexion-extension, internal and external rotation) was determined in relation to the transepicondylar axis and the mechanical femoral axis. The tibial component position (varus-valgus, anterior-posterior slope, internal and external rotation) was determined with regards to the tibial posterior condylar axis and the anatomical and mechanical femoral shaft axis (Figure 2). In addition, a possible femoral and tibial rotational mismatch was determined (Figure 3). The same observers performed these measurements in random order. Both observers performed the measurements twice and were blinded to results from previous observations.Figure 2


A novel standardized algorithm using SPECT/CT evaluating unhappy patients after unicondylar knee arthroplasty--a combined analysis of tracer uptake distribution and component position.

Suter B, Testa E, Stämpfli P, Konala P, Rasch H, Friederich NF, Hirschmann MT - BMC Med Imaging (2015)

Bone tracer uptake quantification of a SPECT/CT in standardized anatomical areas in an asymptomatic patient one year after UKA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4376158&req=5

Fig3: Bone tracer uptake quantification of a SPECT/CT in standardized anatomical areas in an asymptomatic patient one year after UKA.
Mentions: The position of the femoral and tibial UKA components was assessed using a customized software, which is able to reconstruct three-dimensional images from CT data. These 3D models enabled the observer to perform measurements in terms of angles (in degrees) and distances (in mm). The femoral component position (varus-valgus, flexion-extension, internal and external rotation) was determined in relation to the transepicondylar axis and the mechanical femoral axis. The tibial component position (varus-valgus, anterior-posterior slope, internal and external rotation) was determined with regards to the tibial posterior condylar axis and the anatomical and mechanical femoral shaft axis (Figure 2). In addition, a possible femoral and tibial rotational mismatch was determined (Figure 3). The same observers performed these measurements in random order. Both observers performed the measurements twice and were blinded to results from previous observations.Figure 2

Bottom Line: For measurement of component position there was strong agreement between the readings of the two observers; the ICC for the orientation of the femoral component was 0.73-1.00 (intra-observer reliability) and 0.91-1.00 (inter-observer reliability).The ICC for the orientation of the tibial component was 0.75-1.00 (intra-observer reliability) and 0.77-1.00 (inter-observer reliability).Using this standardized approach in clinical studies might be helpful in establishing the diagnosis in patients with pain after UKA.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery and Traumatology, Kantonsspital Baselland (Bruderholz, Liestal, Laifen), CH-4101, Bruderholz, Switzerland. basil.suter@unibas.ch.

ABSTRACT

Background: The introduction of a standardized SPECT/CT algorithm including a localization scheme, which allows accurate identification of specific patterns and thresholds of SPECT/CT tracer uptake, could lead to a better understanding of the bone remodeling and specific failure modes of unicondylar knee arthroplasty (UKA). The purpose of the present study was to introduce a novel standardized SPECT/CT algorithm for patients after UKA and evaluate its clinical applicability, usefulness and inter- and intra-observer reliability.

Methods: Tc-HDP-SPECT/CT images of consecutive patients (median age 65, range 48-84 years) with 21 knees after UKA were prospectively evaluated. The tracer activity on SPECT/CT was localized using a specific standardized UKA localization scheme. For tracer uptake analysis (intensity and anatomical distribution pattern) a 3D volumetric quantification method was used. The maximum intensity values were recorded for each anatomical area. In addition, ratios between the respective value in the measured area and the background tracer activity were calculated. The femoral and tibial component position (varus-valgus, flexion-extension, internal and external rotation) was determined in 3D-CT. The inter- and intraobserver reliability of the localization scheme, grading of the tracer activity and component measurements were determined by calculating the intraclass correlation coefficients (ICC).

Results: The localization scheme, grading of the tracer activity and component measurements showed high inter- and intra-observer reliabilities for all regions (tibia, femur and patella). For measurement of component position there was strong agreement between the readings of the two observers; the ICC for the orientation of the femoral component was 0.73-1.00 (intra-observer reliability) and 0.91-1.00 (inter-observer reliability). The ICC for the orientation of the tibial component was 0.75-1.00 (intra-observer reliability) and 0.77-1.00 (inter-observer reliability).

Conclusions: The SPECT/CT algorithm presented combining the mechanical information on UKA component position, alignment and metabolic data is highly reliable and proved to be a valuable, consistent and useful tool for analysing postoperative knees after UKA. Using this standardized approach in clinical studies might be helpful in establishing the diagnosis in patients with pain after UKA.

Show MeSH