Does Axial Limb Rotation Affect the Alignment Measurements in Deformed Limbs?

Swanson, Kyle E.; Stocks, Gregory W.; Warren, Paul; Hazel, Mark R.; Janssen, Herbert F.

doi:10.1097/00003086-200002000-00029

Cited by 130 publications

(80 citation statements)

References 7 publications

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“…However, this study was conducted in a consecutive series, and the gender proportion of our study population is similar to other TKA series reported from Korea [15][16][17]. Finally, despite our efforts to obtain radiographs of suitable quality, our study is inherently limited by the use of plain radiographs, eg, by issues such as magnification, limb positional variances, and inability to assess three-dimensional features [20,34]. In addition, we assumed the point 1 cm anterior to the end of Blumensaat's line represents a typical registration point for the distal femur center, but the position of this registration point depends on technique.…”

Section: Discussionmentioning

confidence: 71%

Differences between Sagittal Femoral Mechanical and Distal Reference Axes Should Be Considered in Navigated TKA

Chung

Kang

Chang

et al. 2009

Clinical Orthopaedics &Amp; Related Research

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In computer-assisted TKA, surgeons determine positioning of the femoral component in the sagittal plane based on the sagittal mechanical axis identified by the navigation system. We hypothesized mechanical and distal femoral axes may differ on lateral views and these variations are influenced by anteroposterior bowing and length of the femur. We measured angles between the mechanical axis and distal femoral axis on 200 true lateral radiographs of the whole femur from 100 adults. We used multivariate linear regression to identify predictors of differences between the axes. Depending on the method used to define the two axes, the mean angular difference between the axes was as much as 3.8°and as little as 0.0°, with standard differences ranging from 1.7°to 1.9°. Variation between the two axes increased with increased femoral bowing and increased femoral length. Surgeons should consider differences between the mechanical axes and distal femoral axes when they set the sagittal plane position of a femoral component in navigated cases. Our findings also may be relevant when measuring rotation of the femoral component in the sagittal plane from postoperative radiographs or when interpreting femoral component sagittal rotation results reported in other studies.

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Section: Discussionmentioning

confidence: 71%

Differences between Sagittal Femoral Mechanical and Distal Reference Axes Should Be Considered in Navigated TKA

Chung

Kang

Chang

et al. 2009

Clinical Orthopaedics &Amp; Related Research

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“…We chose a deviation range of 3°for all criteria of component orientation and mechanical leg axis assessment. Despite a reported potential error probability of about 2° [32], this protocol is well accepted in the literature and allows for easier comparison [33][34][35]. We note that the specific target values were based on the surgeons' preferences at time of surgery.…”

Section: Discussionmentioning

confidence: 99%

The immediate effect of navigation on implant accuracy in primary mini-invasive unicompartmental knee arthroplasty

Rosenberger

Fink

Quirbach

et al. 2008

Knee Surg Sports Traumatol Arthr

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The success of unicompartmental knee arthroplasty (UKA) is highly dependent on the accuracy of the component alignment. Objective of the present study was to evaluate the immediate effect of image-free computer navigation technology on implant accuracy in primary mini-invasive UKA. This study reviews 40 patients with primary isolated arthritis of the medial compartment of the knee that underwent unicompartmental knee arthroplasty through a minimally invasive approach. A cohort of the 20 most recent consecutive UKA's implanted with standard instrumentation was followed by a cohort of the very first 20 consecutive cases after conversion to the navigated technique. There was no variability regarding implant (Oxford meniscal unicompartmental knee system--Biomet Orthopedics, Inc., Warsaw, Indiana 46580, USA), surgeons and surgical technique, except for the use of the navigation system (Treon plus--Medtronic Inc., Minnesota, MI, USA). The axis alignment and accuracy of implant positioning was measured on postoperative long-leg standing radiographs and standard lateral X-rays with regard to the valgus angle and the coronal and sagittal component angle. In addition, preoperative deformities of the mechanical leg axis, tourniquet time, age, gender, and body mass index were correlated. Statistical analyses were performed using the SPSS 14.0 (SPSS Inc., Chicago, IL, USA) software package. Optimal implant alignment including all measurements in the desired angular range was significantly (P=0.041) higher in the navigated cohort. Navigation eliminated outliers in the frontal mechanical alignment and coronal orientation of the femoral component totally and significantly (P<0.02). Furthermore, navigation narrowed the range of outliers in all other planes of component orientation. There were no statistically significant differences in the mean numerical values between the cohorts, except for the frontal mechanical alignment (P<0.009) and coronal tibial alignment (P<0.037). The average tourniquet time was increased by 10.95 min in the navigated cohort. Our results indicate that navigation immediately improves accuracy of bone cuts and reduces the number of outliers with implementation in UKA.

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“…Malalignment was confirmed from bilateral weight-bearing anteroposterior long cassette radiographs. 27 The weight-bearing line (WBL) ratio was calculated as the perpendicular distance from the WBL to the medial edge of the proximal tibia divided by the full width of the tibial plateau; 28 a ratio less than 50% denotes varus angulation (Fig. 1B).…”

Section: Journal Of Orthopaedic Research January 2009mentioning

confidence: 99%

Proximal gait adaptations in medial knee OA

Briem

Snyder‐Mackler

2008

Journal Orthopaedic Research

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The purpose of this study was to examine interlimb differences in gait kinematics and kinetics in patients with symptomatic medial knee OA. The main objective was to identify hip joint movement strategies that might lower the knee adduction moment and also compensate for decreased knee flexion during weight acceptance. Gait analysis was performed on 32 patients with moderate medial compartment knee OA. Kinetic and kinematic data were calculated and side-to-side comparisons made. Radiographs were used to identify frontal plane alignment. No interlimb difference in the peak knee adduction moment was found (p ¼ 0.512), whereas a greatly reduced hip adduction moment was seen on the involved side (p < 0.001) during the early part of stance. The involved limb flexed significantly less and hip and knee flexion moments were smaller compared to the uninvolved side. Gait adaptations involving a lateral sway of the trunk may successfully lead to relatively lower ipsilateral knee adduction moments, and would further be reflected by a lower adduction moment at the hip. Subjects did not compensate for less knee flexion by any dynamic means, and likely experience a resulting higher joint impact. These gait adaptations may have implications with respect to development of weakness of the ipsilateral hip musculature and progression of multiarticular OA. ß

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Does Axial Limb Rotation Affect the Alignment Measurements in Deformed Limbs?

Cited by 130 publications

References 7 publications

Differences between Sagittal Femoral Mechanical and Distal Reference Axes Should Be Considered in Navigated TKA

Differences between Sagittal Femoral Mechanical and Distal Reference Axes Should Be Considered in Navigated TKA

The immediate effect of navigation on implant accuracy in primary mini-invasive unicompartmental knee arthroplasty

Proximal gait adaptations in medial knee OA

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