Non-invasive assessment of lower limb alignment is accurate for pre-operative planning and post-operative follow up

Jon Clarke, Frederic Picard, Philip Riches, Angela Deakin

Research output: Contribution to conferencePaper

Abstract

Knee alignment is a fundamental measurement in the assessment, monitoring and surgical management of patients with OA. In spite of extensive research into the consequences of malalignment, there is a lack of data regarding the potential variation between supine and standing (functional) conditions. The purpose of this study was to explore this relationship in asymptomatic, osteoarthritic and prosthetic knees. Our hypothesis was that the change in alignment of these three groups would be different. Infrared position capture was used to assess knee alignment for 30 asymptomatic controls and 31 patients with OA, before and after TKA. Coronal and sagittal mechanical femorotibial (MFT) angles in extension (negative values varus/hyperextension) were measured supine and in bi-pedal stance and changes analysed using a paired t-test. To quantify this change in 3D, vector plots of ankle centre displacement relative to the knee centre were produced. Alignment in both planes changed significantly from supine to standing for all three groups, most frequently towards relative varus and extension. In the coronal plane, the mean±SD(°) of the supine/standing MFT angles was 0.1±2.5/−1.1±3.7 for asymptomatic (p=0.001), −2.5±5.7/−3.6±6.0 for osteoarthritic (p=0.009) and −0.7±1.4/ −2.5±2.0 for prosthetic knees (p<0.001). In the sagittal plane, the mean±SD(°) of the supine/standing MFT angles was −1.7±3.3/−5.5±4.9 for asymptomatic (p<0.001), 7.7±7.1/1.8±7.7 for osteoarthritic (p<0.001) and 6.8±5.1/1.4±7.6 for prosthetic knees (p<0.001). The vector plots showed that the trend of relative varus and extension in stance was similar in overall magnitude and direction between the groups. The similarities between each group did not support our hypothesis. The consistent kinematic pattern for different knee types suggests that soft tissue restraints rather than underlying joint deformity may be more influential in dynamic control of alignment from lying to standing. This potential change should be considered when positioning TKA components on supine limbs as post-operative functional alignment may be different.
LanguageEnglish
Number of pages3
Publication statusPublished - Apr 2012
EventCAOS UK Conference - Glasgow, United Kingdom
Duration: 19 Apr 201220 Apr 2012

Conference

ConferenceCAOS UK Conference
CountryUnited Kingdom
CityGlasgow
Period19/04/1220/04/12

Fingerprint

Lower Extremity
Knee
Planning
Prosthetics
Biomechanical Phenomena
Ankle
Kinematics
Foot
Tissue
Infrared radiation
Extremities
Joints
Monitoring
Research

Keywords

  • non-invasive assessment
  • lower limb alignment
  • pre-operative planning
  • post-operative follow up
  • knee alignment
  • knee arthroplasty

Cite this

Clarke, J., Picard, F., Riches, P., & Deakin, A. (2012). Non-invasive assessment of lower limb alignment is accurate for pre-operative planning and post-operative follow up. Paper presented at CAOS UK Conference, Glasgow, United Kingdom.
Clarke, Jon ; Picard, Frederic ; Riches, Philip ; Deakin, Angela. / Non-invasive assessment of lower limb alignment is accurate for pre-operative planning and post-operative follow up. Paper presented at CAOS UK Conference, Glasgow, United Kingdom.3 p.
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Clarke, J, Picard, F, Riches, P & Deakin, A 2012, 'Non-invasive assessment of lower limb alignment is accurate for pre-operative planning and post-operative follow up' Paper presented at CAOS UK Conference, Glasgow, United Kingdom, 19/04/12 - 20/04/12, .

Non-invasive assessment of lower limb alignment is accurate for pre-operative planning and post-operative follow up. / Clarke, Jon; Picard, Frederic; Riches, Philip; Deakin, Angela.

2012. Paper presented at CAOS UK Conference, Glasgow, United Kingdom.

Research output: Contribution to conferencePaper

TY - CONF

T1 - Non-invasive assessment of lower limb alignment is accurate for pre-operative planning and post-operative follow up

AU - Clarke, Jon

AU - Picard, Frederic

AU - Riches, Philip

AU - Deakin, Angela

PY - 2012/4

Y1 - 2012/4

N2 - Knee alignment is a fundamental measurement in the assessment, monitoring and surgical management of patients with OA. In spite of extensive research into the consequences of malalignment, there is a lack of data regarding the potential variation between supine and standing (functional) conditions. The purpose of this study was to explore this relationship in asymptomatic, osteoarthritic and prosthetic knees. Our hypothesis was that the change in alignment of these three groups would be different. Infrared position capture was used to assess knee alignment for 30 asymptomatic controls and 31 patients with OA, before and after TKA. Coronal and sagittal mechanical femorotibial (MFT) angles in extension (negative values varus/hyperextension) were measured supine and in bi-pedal stance and changes analysed using a paired t-test. To quantify this change in 3D, vector plots of ankle centre displacement relative to the knee centre were produced. Alignment in both planes changed significantly from supine to standing for all three groups, most frequently towards relative varus and extension. In the coronal plane, the mean±SD(°) of the supine/standing MFT angles was 0.1±2.5/−1.1±3.7 for asymptomatic (p=0.001), −2.5±5.7/−3.6±6.0 for osteoarthritic (p=0.009) and −0.7±1.4/ −2.5±2.0 for prosthetic knees (p<0.001). In the sagittal plane, the mean±SD(°) of the supine/standing MFT angles was −1.7±3.3/−5.5±4.9 for asymptomatic (p<0.001), 7.7±7.1/1.8±7.7 for osteoarthritic (p<0.001) and 6.8±5.1/1.4±7.6 for prosthetic knees (p<0.001). The vector plots showed that the trend of relative varus and extension in stance was similar in overall magnitude and direction between the groups. The similarities between each group did not support our hypothesis. The consistent kinematic pattern for different knee types suggests that soft tissue restraints rather than underlying joint deformity may be more influential in dynamic control of alignment from lying to standing. This potential change should be considered when positioning TKA components on supine limbs as post-operative functional alignment may be different.

AB - Knee alignment is a fundamental measurement in the assessment, monitoring and surgical management of patients with OA. In spite of extensive research into the consequences of malalignment, there is a lack of data regarding the potential variation between supine and standing (functional) conditions. The purpose of this study was to explore this relationship in asymptomatic, osteoarthritic and prosthetic knees. Our hypothesis was that the change in alignment of these three groups would be different. Infrared position capture was used to assess knee alignment for 30 asymptomatic controls and 31 patients with OA, before and after TKA. Coronal and sagittal mechanical femorotibial (MFT) angles in extension (negative values varus/hyperextension) were measured supine and in bi-pedal stance and changes analysed using a paired t-test. To quantify this change in 3D, vector plots of ankle centre displacement relative to the knee centre were produced. Alignment in both planes changed significantly from supine to standing for all three groups, most frequently towards relative varus and extension. In the coronal plane, the mean±SD(°) of the supine/standing MFT angles was 0.1±2.5/−1.1±3.7 for asymptomatic (p=0.001), −2.5±5.7/−3.6±6.0 for osteoarthritic (p=0.009) and −0.7±1.4/ −2.5±2.0 for prosthetic knees (p<0.001). In the sagittal plane, the mean±SD(°) of the supine/standing MFT angles was −1.7±3.3/−5.5±4.9 for asymptomatic (p<0.001), 7.7±7.1/1.8±7.7 for osteoarthritic (p<0.001) and 6.8±5.1/1.4±7.6 for prosthetic knees (p<0.001). The vector plots showed that the trend of relative varus and extension in stance was similar in overall magnitude and direction between the groups. The similarities between each group did not support our hypothesis. The consistent kinematic pattern for different knee types suggests that soft tissue restraints rather than underlying joint deformity may be more influential in dynamic control of alignment from lying to standing. This potential change should be considered when positioning TKA components on supine limbs as post-operative functional alignment may be different.

KW - non-invasive assessment

KW - lower limb alignment

KW - pre-operative planning

KW - post-operative follow up

KW - knee alignment

KW - knee arthroplasty

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M3 - Paper

ER -

Clarke J, Picard F, Riches P, Deakin A. Non-invasive assessment of lower limb alignment is accurate for pre-operative planning and post-operative follow up. 2012. Paper presented at CAOS UK Conference, Glasgow, United Kingdom.