Anatomy of the epicondyles of the distal femur: MRI analysis of normal knees
Abstract
Knowledge of precise anatomic landmarks and relationships of the distal femur can be helpful in knee surgery, especially primary and revision total knee arthroplasty. We analyzed 104 consecutive routine knee magnetic resonance imaging studies to define useful landmarks and relationships. The epicondyles are described, and the relationship of the epicondyles to the joint line is defined in multiple planes. Some significant gender differences were noted. The distance from the epicondyles to the joint line correlates with the transepicondylar width of the distal femur. This information can be helpful in determining appropriate joint line position intraoperatively. The posterior condylar angle averaged 3.11° for all patients, and a tendency for the posterior condylar angle to increase with age was noted, but further study of this tendency is needed.
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Cited by (208)
Femoral Neck Anteversion: Which Distal Femur Landmark Matters?
2024, Arthroplasty TodayFemoral neck anteversion has traditionally been measured by the angle between the distal femur posterior condylar axis (PCA) and a line drawn through the center of the femoral head and neck. While less common, the transepicondylar axis (TEA) has also been used to reference femoral neck anteversion. The purpose of this study was to compare femoral neck version of the PCA vs the TEA using computerized tomography (CT).
A total of 1507 femoral CTs were included. Precise bony landmarks were established: lateral epicondyle, medial epicondyle, posteromedial condyle, posterolateral condyle, center of the femoral neck, and center of the femoral head. Femoral version was calculated between the head and neck axis and either the PCA or TEA. Differences between sex and ethnicity were evaluated.
The mean femoral anteversion was 12.7° ± 9.1° based on the PCA and 11.5° ± 7.9° based on the TEA (mean difference 1.2° ± 1.9°, P < .001). Males were less anteverted than females (9.8° ± 7.6° vs 13.5° ± 7.8°, P < .001). African Americans had less anteversion than other groups (8.1° ± 9.2° vs 11.5° ± 7.8°, P = .04), while Asians were more anteverted than other groups (12.1° ± 9.0° vs 11.2° ± 7.3°, P = .04). These values were referenced on the TEA.
In this series of over 1500 femoral CT scans, the mean difference between anteversion measurements referencing the PCA and TEA was 1.2°. Native femoral version varied widely between gender and ethnic groups. Extreme femoral version, defined as <0° or >30°, was present in 11.8% of patients referencing the PCA.
[Translated article] Study of femoral component malrotation as a cause of pain after total knee arthroplasty
2024, Revista Espanola de Cirugia Ortopedica y TraumatologiaThe total knee arthroplasty (TKA) has been shown to be a successful and cost-benefit procedure in terms of pain improvement in patient with symptomatic knee osteoarthritis. However, almost a 20% of the patients are not satisfied with the result of the surgery.
We have carried out a transversal unicentric cases controls study with clinical cases of the own hospital, obtained by a clinical records revision. A total of 160 patients with a TKA with at least 1 year of follow-up were selected. Demographic variables, functional scales (WOMAC and VAS) and rotation of the femoral component through the analysis of the images obtained by CT scan were collected.
The total was 133 patients that was divided in two groups. A control group and pain group. The Control group was made up of 70 patients with a mean age of 69.59 years (23 men and 47 women) and the pain group was made up of 63 patients with a mean age of 69.48 years (13 men and 50 women). We didn’t find difference regarding the analysis of the rotation of the femoral component. In addition, we were not found significant differences when applying a stratification by sex. And, the analysis of the malrotation of the femoral component, previously defining limits of value rotation considered as extreme, in any of the case did not show significant differences.
The results of the study confirm that malrotation of the femoral component had no influence on the presence of pain at a minimum of one year of follow-up after TKA implantation.
La artroplastia total de rodilla ha demostrado ser un procedimiento exitoso y coste-efectivo en cuanto a la mejoría del dolor en pacientes con artrosis de rodilla sintomática. Sin embargo, en torno a un 20% de pacientes no está satisfecho con el resultado de la intervención.
Realizamos un estudio transversal de casos y controles, unicéntrico con casos hospitalarios, obtenidos mediante la revisión de historias clínicas. Se seleccionaron 160 pacientes portadores de artroplastia total de rodilla con un seguimiento mínimo de un año. Se registraron variables demográficas, escalas funcionales (WOMAC y EVA) y la rotación del componente femoral mediante análisis de imágenes obtenidas por TC.
La muestra final estuvo compuesta por 133 pacientes divididos en grupo control formado por 70 pacientes, con una edad media de 69,59 años (23 hombres y 47 mujeres) y grupo dolor formado por 63 pacientes, con una edad media 69,48 años (13 hombres y 50 mujeres). No encontramos diferencias en cuanto al análisis de la rotación del componente femoral. Tampoco hubo diferencias significativas al aplicar una estratificación por sexo. El análisis de la malrotación del componente femoral, definiendo unos límites de valor de rotación considerados como extremos, no mostró diferencias significativas en ninguno de los casos.
Los resultados del estudio confirman que la malrotación del componente femoral no tuvo influencia sobre la presencia de dolor a un mínimo de un año de seguimiento tras la implantación de una artroplastia total de rodilla.
ACR Appropriateness Criteria® Imaging After Total Knee Arthroplasty: 2023 Update
2023, Journal of the American College of RadiologyTotal knee arthroplasty is the most commonly performed joint replacement procedure in the United States. This manuscript will discuss the recommended imaging modalities for six clinical variants; 1. follow-up of symptomatic or asymptomatic patients with a total knee arthroplasty. Initial imaging, 2. Suspected infection after total knee arthroplasty. Additional imaging following radiographs, 3. Pain after total knee arthroplasty. Infection excluded. Suspect aseptic loosening or osteolysis or instability. Additional imaging following radiographs, 4. Pain after total knee arthroplasty. Suspect periprosthetic or hardware fracture. Additional imaging following radiographs, 5. Pain after total knee arthroplasty. Measuring component rotation. Additional imaging following radiographs, and 6. Pain after total knee arthroplasty. Suspect periprosthetic soft-tissue abnormality unrelated to infection, including quadriceps or patellar tendinopathy. Additional imaging following radiographs.
The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.
The optimal landmark for setting femoral component rotation in primary TKA remains a debate. This study compares the Anterior-Posterior Axis (APA) versus the Transepicondylar Axis (TEA) in patients undergoing simultaneous bilateral TKA, where one reference line was randomized to each knee. Implant mating was assessed via post-operative CT scans.
The study included 32 patients with osteoarthritis in both knees with similar varus deformities. All patients underwent the same surgical procedure on both knees, aside from the selected femoral rotation axis line: APA randomized to one side and TEA to the contralateral. Post-operative CT scans were performed in extension to assess in-vivo mating.
CT scan analysis showed mean rotation of the femoral implant externally rotated relative to the radiographic TEA with no significant difference between the APA and TEA groups (p = 0.28). Tibial implant rotation was also externally rotated to the radiographic TEA with no significant difference (p = 0.59). Femoral-tibial implant mating showed a mean external rotation of the tibia relative to the femur in both groups: 0.86 ± 4.0° external rotation in the APA group and 0.23 ± 3.7° external rotation in the TEA group. There was no significant difference between groups (p = 0.52). The range of mating mismatch was 15° in the APA group and 16.5° in the TEA group.
When using a measured resection, posterior referencing technique, post-operative femoral-tibial implant mating measured by CT scan showed no superiority comparing the APA method versus the TEA method.
Level OF EVIDENCE: 2
Randomized prospective study.
Study of femoral component malrotation as a cause of pain after total knee arthroplasty
2023, Revista Espanola de Cirugia Ortopedica y TraumatologiaLa artroplastia total de rodilla (ATR) ha demostrado ser un procedimiento exitoso y coste-efectivo en cuanto a la mejoría del dolor en pacientes con artrosis de rodilla sintomática. Sin embargo, en torno a un 20% de pacientes no están satisfechos con el resultado de la intervención.
Realizamos un estudio transversal de casos y controles, unicéntrico con casos hospitalarios, obtenidos mediante la revisión de historias clínicas. Se seleccionaron 160 pacientes portadores de ATR con un seguimiento mínimo de un año. Se registraron variables demográficas, escalas funcionales (WOMAC y EVA) y la rotación del componente femoral mediante análisis de imágenes obtenidas por TC.
La muestra final estuvo compuesta por 133 pacientes divididos en grupo control, formado por 70 pacientes con una edad media de 69,59 años (23 hombres y 47 mujeres), y grupo dolor, formado por 63 pacientes con una edad media 69,48 años (13 hombres y 50 mujeres). No encontramos diferencias en cuanto al análisis de la rotación del componente femoral. Tampoco hubo diferencias significativas al aplicar una estratificación por sexo. El análisis de la malrotación del componente femoral, definiendo unos límites de valor de rotación considerados como extremos, no mostró diferencias significativas en ninguno de los casos.
Los resultados del estudio confirman que la malrotación del componente femoral no tuvo influencia sobre la presencia de dolor a un mínimo de un año de seguimiento tras la implantación de una ATR.
The total knee arthroplasty (TKA) has been shown to be a successful and cost-benefit procedure in terms of pain improvement in patient with symptomatic knee osteoarthritis. However, almost a 20% of the patients are not satisfied with the result of the surgery.
We have carried out a transversal unicentric cases controls study with clinical cases of the own hospital, obtained by a clinical records revision. A total of 160 patients with a TKA with at least 1 year of follow-up were selected. Demographic variables, functional scales (WOMAC and VAS) and rotation of the femoral component through the analysis of the images obtained by CT scan were collected.
The total was 133 patients that was divided in two groups. A control group and pain group. The control group was made up of 70 patients with a mean age of 69.59 years (23 men and 47 women) and the pain group was made up of 63 patients with a mean age of 69.48 years (13 men and 50 women). We did not found difference regarding the analysis of the rotation of the femoral component. In addition, we were not found significant differences when applying a stratification by sex. The analysis of the malrotation of the femoral component, previously defining limits of value rotation considered as extreme, in any of the case did not show significant differences.
The results of the study confirm that malrotation of the femoral component had no influence on the presence of pain at a minimum of one year of follow-up after TKA implantation.
Hybrid curvature-geometrical detection of landmarks for the automatic analysis of the reduction of supracondylar fractures of the femur
2022, Computer Methods and Programs in BiomedicineBackground and objective:The analysis of the features of certain tissues is required by many procedures of modern medicine, allowing the development of more efficient treatments. The recognition of landmarks allows the planning of orthopedic and trauma surgical procedures, such as the design of prostheses or the treatment of fractures. Formerly, their detection has been carried out by hand, making the workflow inaccurate and tedious. In this paper we propose an automatic algorithm for the detection of landmarks of human femurs and an analysis of the quality of the reduction of supracondylar fractures.
Methods:The detection of anatomical landmarks follows a knowledge-based approach, consisting of a hybrid strategy: curvature and spatial decomposition. Prior training is unrequired. The analysis of the reduction quality is performed by a side-to-side comparison between healthy and fractured sides. The pre-clinical validation of the technique consists of a two-stage study: Initially, we tested our algorithm with 14 healthy femurs, comparing the output with ground truth values. Then, a total of 140 virtual fractures was processed to assess the validity of our analysis of the quality of reduction. A two-sample t test and correlation coefficients between metrics and the degree of reduction have been employed to determine the reliability of the algorithm.
Results:The average detection error of landmarks was maintained below 1.7 mm and 2 (p 0.01) for points and axes, respectively. Regarding the contralateral analysis, the resulting P-values reveal the possibility to determine whether a supracondylar fracture is properly reduced or not with a 95% of confidence. Furthermore, the correlation is high between the metrics and the quality of the reduction.
Conclusions:This research concludes that our technique allows to classify supracondylar fracture reductions of the femur by only analyzing the detected anatomical landmarks. A initial training set is not required as input of our algorithm.
No benefits or funds were received in support of this study.