Posterior Cortical Axis: A New Landmark to Control Femoral Component Rotation in Total Knee Arthroplasty

Matziolis, Doerte; Meiser, Marius; Sieber, Norbert; Teichgräber, Ulf; Matziolis, Georg

doi:10.3928/01477447-20170117-01

Cited by 10 publications

(16 citation statements)

References 19 publications

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“…Theoretically, the TEA is a reliable reference axis for the proper location of the femoral component, but it is challenging to identify the TEA intraoperatively because the geometry has a low profile, and the epicondyles are covered by soft tissue [ 6 , 7 ]. For correct femoral rotation in TKA, preoperative planning using computed tomography (CT) or magnetic resonance imaging (MRI) has been advocated by some surgeons [ 8 , 9 ]. Although the PCA is the most apparent marker during surgery, the posterior condylar cartilage cannot be detected on CT [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of the presence of the articular cartilage on the femoral component rotation in total knee arthroplasty in female and varus osteoarthritis knees

Nam

Koh

Kim³

et al. 2020

J Orthop Surg Res

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Purpose Surgical techniques for total knee arthroplasty (TKA) require femoral rotational corrections that alter the position of the surface of the posterior femoral joint especially in kinematic alignment. However, preoperative planning of TKA based on computed tomography (CT), without knowing the femoral cartilage thickness, may cause post-surgery failures in femoral rotation. Therefore, this study aimed to evaluate the effects of posterior condyle cartilage thickness on rotational alignment in the femoral component. Methods Three-dimensional magnetic resonance imaging (MRI) scans were obtained for 139 male and 531 female osteoarthritis patients. The angles defined by the femoral posterior condylar axis (PCA) and the surgical transepicondylar axis (TEA) were evaluated with respect to the presence of cartilage. Additionally, these effects were evaluated with respect to patient gender and varus/valgus condition. Results In all patients, the angle between the TEA and PCA was significantly greater in the presence of cartilage than in the absence of cartilage. This result was also seen in female patients. However, there was no difference in the TEA/PCA angle in male patients based on the presence of cartilage. The TEA/PCA angle was significantly greater in the presence of cartilage than in the absence of cartilage in the female varus group. However, there were no differences in the TEA/PCA angle based on the presence of cartilage in the male varus/valgus and female valgus groups. Cartilage thickness in the posterior femoral condyle was significantly greater on the lateral side than on the medial side in all and male patients. However, there was no difference between the genders regarding cartilage thickness. Conclusion Surgical planning for TKA based on CT does not consider articular cartilage and could lead to external malrotation of the femoral implant. Therefore, the effect of the remaining posterior condylar cartilage should be considered by surgeons to prevent over-rotation of the femoral component, especially in female varus knees.

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Section: Introductionmentioning

confidence: 99%

Effect of the presence of the articular cartilage on the femoral component rotation in total knee arthroplasty in female and varus osteoarthritis knees

Nam

Koh

Kim³

et al. 2020

J Orthop Surg Res

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“…Regarding the medial/lateral axes, and, in the case of the measured resection technique, adjustment of the femoral component parallel to the surgical epicondylar axis (SEA), which is the line connecting the lateral epicondyle prominence and the sulcus of the medical epicondyle (Fig. ), has become established as the implantation goal (Matziolis et al, ). This is largely because it approximates the flexion‐extension kinematic axis of the knee at various ranges of motion (Asano et al, ; Merican et al, ; Kobayashi et al, ).…”

Section: Introductionmentioning

confidence: 99%

Femoral rotational asymmetry is a common anatomical variant

2018

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The sulcus line (SL) is a three-dimensional landmark that corrects for individual variation in the coronal alignment of the trochlear groove in contrast to the traditional Whiteside's line (WL). Femoral rotational asymmetry (FRA) is an anatomical variation in which the posterior condyles and trochlear groove are not perpendicular to each other. This study aims to measure the SL and assess its reliability relative to WL, in addition to measuring and classifying the FRA. A retrospective analysis of a series of 191 CT scans of nonarthritic knees was performed. Measurements were taken of rotational landmarks in three-dimensional reconstructions. The variability and outlier rate of SL was less than WL (P < 0.05), however, it was also greater than the posterior condylar line (PC) (P < 0.05). Averaging the PC + 3° and the SL did not change the rate of femoral malrotation relative to the surgical epicondylar axis (SEA) (P > 0.05), however it decreased the rate of change of the rotational alignment of the trochlear groove between the native knee and the prosthetic knee from 31% to 5% (P < 0.05). FRA was classified and was >5° in 56/191 (29%) of cases. The SL technique is more accurate than WL for determining the rotational alignment of the trochlear groove. Nonarthritic femora have a high rate of rotational asymmetry. Identifying and classifying FRA in individual cases allows the femoral component to be inserted in a position which gives the best possible match to both the native posterior condyles and trochlear groove. Clin. Anat. 31:551-559, 2018. © 2018 Wiley Periodicals, Inc.

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“…It is difficult to identify the sulcus of the medial epicondyle by palpation, and variations in the shapes of the epicondyles make it difficult for surgeons to recognize the TEA reference points [10]. During the postoperative evaluation of component rotation using computed tomography (CT), Whiteside's line and the posterior condylar axis are unavailable as references; hence, the TEA must be determined directly [11]. However, femoral implants, particularly in implants with femoral boxes, may restrict the determination of TEA [11].…”

Section: Introductionmentioning

confidence: 99%

“…During the postoperative evaluation of component rotation using computed tomography (CT), Whiteside's line and the posterior condylar axis are unavailable as references; hence, the TEA must be determined directly [11]. However, femoral implants, particularly in implants with femoral boxes, may restrict the determination of TEA [11].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, recent studies have suggested two reference axes in the anterior and posterior femur as alternatives to the conventional reference axes in the event of distortion. The trochlear anterior line (TAL) is a line connecting the most anterior points of the medial and lateral femoral condyles [12][13][14][15], whereas the femoral posterior cortical axis (FPCA) is a line parallel to the posterior surface, proximal to the point where the femoral trochlea ends [11]. These studies have provided not only valuable supplementary information for the rotational alignment of the femoral component but also important anthropometric data of the distal femur that can be used for designing implant.…”

Section: Introductionmentioning

confidence: 99%

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The posterior cortical axis as an alternative reference for femoral component placement in total knee arthroplasty

Nam

Koh

Kang³

et al. 2020

J Orthop Surg Res

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Background Although several reference axes have been established for determining femoral rotational alignment during total knee arthroplasty (TKA), the most accurate axis is undetermined. This study determines the relationship between the posterior cortical axis (PCA) and the trochlear anterior line (TAL) of the femur in relation to the epicondylar axis. Methods A total of 341 patients who underwent TKA for osteoarthritis were enrolled. Patients who had undergone previous bony surgery or replacement that might have changed the femoral geometry were excluded. Finally, 336 patients (200 females and 136 males) were included in the study. The angles between the transepicondylar axis (TEA) and TAL and TEA and the femoral PCA (FPCA) were evaluated. We also assessed whether there was any significant differences in variance and gender in these two angles. Student’s t tests were used to determine the significance of coronal alignment and any gender-based differences. The variances between the TAL/TEA and FPCA/TEA angles were compared using F tests. Results The FPCA was externally rotated by 2.6° ± 3.6°, and the trochlear anterior line was internally rotated by 5.2° ± 5.5°, relative to the TEA. Gender-based differences were observed in the comparisons between anatomical references and TEA. Conclusions The FPCA is a more conservative landmark than the TAL for intraoperative or postoperative approximation of the TEA. When conventional reference axes, such as the posterior condylar axis and the anteroposterior axis, are inaccurate, surgeons can refer to this alternative reference. These findings demonstrate that the FPCA may be useful for determining the rotational alignment of the femoral component before and during TKA.

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Posterior Cortical Axis: A New Landmark to Control Femoral Component Rotation in Total Knee Arthroplasty

Cited by 10 publications

References 19 publications

Effect of the presence of the articular cartilage on the femoral component rotation in total knee arthroplasty in female and varus osteoarthritis knees

Effect of the presence of the articular cartilage on the femoral component rotation in total knee arthroplasty in female and varus osteoarthritis knees

Femoral rotational asymmetry is a common anatomical variant

The posterior cortical axis as an alternative reference for femoral component placement in total knee arthroplasty

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