The femoral trochlear anterior line is a better alternative intra-operative reference compared to femoral anterior tangent line for femoral rotation in both genders in total knee arthroplasty

Objective: Computer assisted total knee arthroplasty (CA TKA) platforms can provide detailed kinematic data that is presented in various forms including a coronal plane graphic that maps the flexion arc from full extension to deep flexion. Graphics obtained from normal tibiofemoral articulations reveal varied and complex kinematic patterns that have yet to be explained. An understanding of what drives curve variation would allow prediction of how a preoperative curve would be altered by total knee arthroplasty. Implant position could then be tailored to maintain a desirable curve or avoid an undesirable one. Methods: An articulated lower limb saw bone with a stable hip pivot was obtained. Adjustable osteotomies were created so that femoral torsion, femoral varus-valgus and tibial varus-valgus could be altered independently. The saw bone limb was registered with a CA TKA navigation system using the posterior condyles as a rotational axis. Axial and coronal plane morphology of the distal femur and coronal plane morphology of the proximal tibia were systematically altered and a kinematic curve obtained for each morphologic combination. Femoral rotational position was varied from 100 of internal torsion to 100 of external torsion in 20 increments. Similarly, femoral coronal position was varied from 20 of varus to 60 of valgus and tibial coronal position was varied from 5.50 of varus to 10 of valgus. Curves were obtained by manually flexing the joint through a full range of motion with the femoral condyles in contact with proximal tibia at all times. Results: Varying femoral rotation has no effect in full extension but drives the curve away from neutral as the knee flexes. Maximal deviation is seen at around 900 of flexion. Internal torsion drives the curve into valgus as the knee flexes and external torsion has a reciprocal effect. Varying femoral varus-valgus causes maximal deviation from neutral in full extension. Femoral varus drives the curve from varus in extension towards valgus as the knee flexes with the effect peaking in maximal flexion. Femoral valgus has a reciprocal effect. Varying tibial varus-valgus has no effect on curve shape but does move the curve either side of neutral. Complex (parabolic) curves are caused by large rotations or the opposing effects of femoral varus-valgus and femoral rotation. The modal human anatomy of slight femoral internal rotation, slight femoral valgus and slight tibial varus produces a straight neutral curve. Conclusion: Kinematic curve shape is driven by distal femoral anatomy. The typical changes made to distal femoral articular anatomy in TKA by externally rotating a neutrally orientated femoral component will bring many native curves towards neutral. Externally rotating when the preoperative curve begins neutral and drives into varus as the knee flexes will drive the curve harder into varus. Conversely, kinematic femoral placement will reconstitute the premorbid curve morphology. Which outcome is preferable has yet to be determined.

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Accuracy and reliability of distal femoral rotation measurements using the transepicondylar axis in total knee arthroplasty: A cadaver study

Bali Medical Journal ◽

10.15562/bmj.v6i3.683 ◽

2017 ◽

Vol 6 (3) ◽

pp. 491

Author(s):

Seyyed Morteza Kazemi ◽

Reza Minaei ◽

Mohammad Nabi Bahrami

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Cadaver Study ◽

Femoral Rotation ◽

Transepicondylar Axis ◽

Total Knee

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Comparison of Femoral Rotation in Total Knee Arthroplasty with Measured Resection Technique and Balanced Flexion Gap Technique

The Internet Journal of Orthopedic Surgery ◽

10.5580/2b82 ◽

2012 ◽

Vol 19 (2) ◽

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Femoral Rotation ◽

Flexion Gap ◽

Gap Technique ◽

Measured Resection ◽

Total Knee

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Optimized functional femoral rotation in navigated total knee arthroplasty considering ligament tension

The Knee ◽

10.1016/j.knee.2009.12.001 ◽

2010 ◽

Vol 17 (6) ◽

pp. 381-386 ◽

Cited By ~ 20

Author(s):

T.A. Walde ◽

J. Bussert ◽

S. Sehmisch ◽

P. Balcarek ◽

K.M. Stürmer ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Femoral Rotation ◽

Ligament Tension ◽

Total Knee

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Femoral rotation in total knee arthroplasty: a comparison of patient individualized jigs with gap balancing in relation to anatomic landmarks

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-015-3836-9 ◽

2015 ◽

Vol 25 (6) ◽

pp. 1712-1719 ◽

Cited By ~ 7

Author(s):

W. Fitz ◽

S. Jäger ◽

J. S. Rieger ◽

E. Seebach ◽

R. G. Bitsch

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Femoral Rotation ◽

Anatomic Landmarks ◽

Gap Balancing ◽

Total Knee

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Distal Femoral Rotation Correlates With Proximal Tibial Joint Line Obliquity: A Consideration for Kinematic Total Knee Arthroplasty

The Journal of Arthroplasty ◽

10.1016/j.arth.2017.12.025 ◽

2018 ◽

Vol 33 (6) ◽

pp. 1936-1944 ◽

Cited By ~ 3

Author(s):

Chung Kia Ng ◽

Jerry Yongqiang Chen ◽

Jared Ze Yang Yeh ◽

Jade Pei Yuik Ho ◽

Azhar M. Merican ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Joint Line ◽

Femoral Rotation ◽

Joint Line Obliquity ◽

Total Knee

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Anterior referencing versus posterior referencing in total knee arthroplasty: a prospective observational study

International Journal of Research in Orthopaedics ◽

10.18203/issn.2455-4510.intjresorthop20164789 ◽

2016 ◽

Vol 3 (1) ◽

pp. 66 ◽

Cited By ~ 1

Author(s):

Preetesh Choudhary ◽

Skand Bahre ◽

Vinay Tantuway ◽

Ashok Nagla ◽

Avinash Jain ◽

...

Keyword(s):

Total Knee Arthroplasty ◽

Knee Arthroplasty ◽

Prospective Observational Study ◽

Femoral Condyle ◽

Posterior Instrumentation ◽

Medial Femoral Condyle ◽

Femoral Rotation ◽

Inclusion Criteria ◽

Component Rotation ◽

Total Knee

Background: Femoral component rotation in total knee arthroplasty (TKA) is essential for patella-femoral tracking, ﬂexion gap balance and normal kinematic function of the knee. The two referencing techniques used for sizing and adjudging the femoral rotation are anterior referencing (AR) and posterior referencing (PR).The current study was designed so as to identify which referencing system determines the femoral rotation more accurately.Methods: This study involved 34 consecutive patients (22 females and 12 males) with 60 osteoarthritic knees (bilateral=26; unilateral =8) who satisﬁed the inclusion criteria. The trans-epicondylar axis, was taken as gold standard to adjudge the correct femoral rotation and was marked as E. The axis of rotation as per anterior instrumentation (A), and as per posterior instrumentation (P) were marked and compared as to which of the axis (A or P) was parallel to E.Results: A was always parallel to E, however P was parallel to E in 42 knees. In 18 knees (6 with valgoid deformity, 12 with hypertrophic osteoarthritis involving the medial femoral condyle), P and E tend to converge laterally, suggestive of excessive internal rotation. Conclusions: Anterior referencing determines femoral rotation more accurately than posterior referencing for knees with severe valgoid deformity or those with hypertrophic osteoarthritis involving the overgrowth of medial femoral condyle.

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