scholarly journals A comparison of femoral component rotation after total knee arthroplasty in Kanekasu radiographs, axial CT slices and 3D reconstructed images

Author(s):  
Emma L. Robertson ◽  
Martin Hengherr ◽  
Felix Amsler ◽  
Michael T. Hirschmann ◽  
Dominic T. Mathis

Abstract Objective To compare the posterior condylar angle measured with Kanekasu radiograph and 2D-CT with the gold standard 3D-CT following primary total knee arthroplasty (TKA). Methods Eighty-two knees with pain following TKA were included in this retrospective study. Two independent raters measured the anatomical and surgical posterior condylar angles twice on each Kanekasu radiograph and 2D-CT. These measurements were compared against the 3D-CT measurement. The intra- and interrater reliability of the Kanekasu radiograph and 2D-CT and the correlation with 3D-CT were calculated. Results The intra- and interrater reliability for measurements of the anatomical posterior condyle angle for the Kanekasu radiograph and the 2D-CT were excellent for both raters (0.85–0.92). For the less experienced rater 1, the intrarater reliability was significantly better for 2D-CT than Kanekasu radiograph for measuring both the surgical (p < 0.01) and anatomical posterior condyle angles (p < 0.05). For the experienced rater 2, the intrarater reliability was significantly better for Kanekasu radiograph than 2D-CT for measurement of the surgical posterior condyle angle (p < 0.05). The correlation with 3D-CT is higher in 2D-CT than in Kanekasu radiograph (p < 0.01). While the Kanekasu radiograph predicts the 3D-CT angle with 65.9%, 2D-CT can measure the true angle with 82.9% certainty. Conclusion Measurements using the anatomical transepicondylar axis are easier to replicate compared to the surgical transepicondylar axis. In comparison with the gold standard 3D-CT, 2D-CT showed a significantly higher correlation with 3D-CT than the Kanekasu measurements. If 3D-CT is available, it should be preferred over 2D-CT and Kanekasu view radiograph for femoral component rotation measurements.

2019 ◽  
Vol 33 (10) ◽  
pp. 971-977
Author(s):  
Diana K. Lee ◽  
Matthew J. Grosso ◽  
David P. Trofa ◽  
Julian J. Sonnenfeld ◽  
H. John Cooper ◽  
...  

AbstractProper femoral component rotation in total knee arthroplasty (TKA) is important, given the prognostic impact of a poorly positioned component. The purpose of this observational study was to determine the incidence of femoral component malrotation using posterior condylar axis (PCA) referencing. A total of 100 knees in 92 patients with varus gonarthritis of the knee undergoing primary TKA using a standard medial parapatellar approach were evaluated intraoperatively. After distal femoral resection, the standard femoral sizing guide referencing the posterior condylar axis was used to set femoral component rotation. This was then compared with both the transepicondylar (TEA) and trochlear anteroposterior axes (TRAx). Disparites were recorded and corrected in line with the epicondylar axis. Rotational adjustment for addition of further external rotation was made in 13 (13.0%) cases. In seven cases, the medial pin sites were raised between 1 and 3 mm, and in six cases, the lateral pin site was lowered between 1 and 3 mm (based on risk of notching the femoral cortex). It is critical to not rely exclusively on the PCA to confirm rotational positioning of the femoral component as predicted by posterior condylar referencing guides. Intraoperative adjustment and confirmation using the TEA and TRAx occurred in 13% of primary TKA cases, which might have, otherwise, had a significant effect on the clinical outcome.


2017 ◽  
Vol 5 (2_suppl2) ◽  
pp. 2325967117S0010
Author(s):  
Zeki Taşdemir ◽  
Hüseyin Bilgehan Çevik ◽  
Nurzat Elmalı ◽  
Özgür Baysal

Objectives: Purpose of this study is to as certain consistency between posterior condylar axis (PCA) + 3˚ external rotation line and clinical transepicondylar axis (cTEA) line in primary total knee arthroplasty cases. Materials-Methods: During surgery, following distal femoral cut PCA +3 degree external rotation line and cTEA line drawn on the distal femoral cutting surface by ruler and pencil. The both lines on distal femur were recorded by digital camera and relationship between lines was ascertained in reference to PCA +3 degree external rotation [parallel (P), Internal rotation (IR) and External Rotation (ER)]. Results: 9 knees of 9 patients [1 men, 8 women; average age 67 (59-80 age)] were constituted the study group. Evaluation results of the photographs revealed that clinical TEA line in comparison PCA +3 degrees external rotation line was ER in 9 knees (100%) whose mean angles 2.7˚ (1-6) and detected external roation with mean angle 4.7˚ (2-7) in 9 knees. Conclusion:: For determination of FC rotation in surgery setting, different results between cTEA and PCA + 3 degrees techniques possibly may due to disadvantages of techniques and anatomic variation of distal femur. Thus, using both techniques for check each other’s results seems unsafe. In custom made prosthesis, which can be done in the future it will be measured by CT. Keywords: Total knee arthroplasty, femoral component, rotational alignment, femoral transepicondylar axis, posterior condylar axis


2018 ◽  
Vol 6 (4_suppl2) ◽  
pp. 2325967118S0002
Author(s):  
Peter Balcarek ◽  
Tobias Brodkorb ◽  
Tim Walde

The femoral posterior condylar offset (PCO) has been viewed with increased significance for knee joint movement patterns and has been discussed for its possible implication for femoral component rotation in total knee arthroplasty (TKA). However, a great inter-individual variability in medial and lateral PCO size has also been demonstrated. Though the medial and lateral PCO seem closely related to the functional flexion axis (fFA), determined by the radius curvature of the medial and lateral femoral condyle, the relationship of both parameters considering their impact on the accuracy of established reference axes for determining femoral component rotation in TKA remains unknown. The objective of this paper was, therefore, to compare the individual fFA with the anatomical and surgical transepicondylar axis (aTEA; sTEA) and with the posterior condylar axis (PCA) considering the medial and lateral PCO size. It was hypothesized that the disparity of the PCO influences the accuracy of the sTEA, aTEA, and PCA for determination of femoral component rotation in TKA. MRI investigations of 56 consecutive non-arthritic knee joints (male/female 28/28; mean age 22.8 years; range 16-59 years) were used for this study. Coronal, sagittal and transverse MRI images were used to measure the medial and lateral PCO and to determine the fFA, aTEA, sTEA, and PCA for each subject as described previously. A paired two-tailed t-test was used to test for differences between the medial and lateral PCO sizes. Deviation of the aTEA, sTEA and PCA from the fFA were analyzed with a one-sample t-test. Correlation analysis (Pearson r) was used to determine the relationship between the PCO ratio (medial-to-lateral PCO) and the deviation of the aTEA, sTEA and PCA from the fFA in each subject. The level of significance was set at 0.05. The mean medial PCO was 34.0 mm (90%CI 28.72-30.55 mm; range 26.3 to 44.7 mm) and the lateral PCO averaged 29.64 mm (90%CI 30.3-31.4 mm; range 14.3 to 39.1 mm) (p<0.0001). The medial-to-lateral PCO ratio was 1.16 (90%CI 1.13 -1.19; range 0.93 to 1.85). The aTEA showed an increased external rotation in relation to the fFA throughout the whole PCO ratio range (mean deviation 4.2°; 95%CI 3.8°-4.6°; range -4.2° to 10.1°; p<0.0001), whereas the sTEA tends towards a slight but significant internal rotation throughout the PCO ratio range (mean deviation -1.6°; 95%CI -2.1°- -1.2°; range -8.1° to 4.8°; p<0.0001). The PCA showed the best conformity with the fFA (mean difference -0.2°; 95%CI -0.5°-0.2°; range -6° to 5.3°; p=0.36) and was most robust against medial-to-lateral PCO variations. A weak but significant positive correlation between the PCO ratio and the deviation from the fFA was solely found for the sTEA (r=0.28; p=0.042). Differences of the medial and lateral PCO size are a common finding. The PCA had the best match with the fFA, regardless of medial-to-lateral PCO disparity. Only the sTEA was influenced to a small extent by variation of the PCO-ratio.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Ji-Hoon Nam ◽  
Yong-Gon Koh ◽  
Kiwon Kang ◽  
Joon-Hee Park ◽  
Kyoung-Tak Kang

Abstract 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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