Deciding on the optimal distal femoral cutting angle (DFCA) during a total knee replacement (TKR) is a crucial step that can significantly affect the outcome of the surgery. In recent years, the standard practice of utilizing a fixed distal femoral valgus cutting angle has come under scrutiny. A letter to the editor, published in the “Journal of Clinical Orthopaedics and Trauma” (DOI: 10.1016/j.jcot.2018.11.001), reignites this debate, prompting us to delve into the growing body of research on this topic.

The overarching question is whether the one-size-fits-all approach of a fixed valgus cutting angle can be justified when performing a total knee replacement, given the anatomical variations among individuals and populations. This article provides an exhaustive review of the subject, offering insights from the latest studies and perspectives from leading orthopaedic experts.

Understanding the Fixed Distal Femoral Valgus Cutting Angle

Total knee replacement (TKR) is a highly successful surgical procedure for patients suffering from debilitating knee conditions, particularly osteoarthritis. One of the technical aspects of TKR is determining the DFCA, which is pivotal in ensuring proper alignment and function of the knee joint postoperatively. Traditionally, surgeons have applied a fixed DFCA, typically around 5 to 7 degrees, to counter the natural angle of the femur and achieve mechanical axis alignment.

The Argument for Fixed Angles: Simplicity and Standardization

Proponents of the fixed-angle method believe it simplifies the procedure and provides a standardized approach that can lead to consistently positive results. In a study by Vaishya et al. (PMC5995008), the authors concluded that a fixed DFCA is justifiable in total knee arthroplasty. They suggest that using a standard angle simplifies surgical technique and instrumentation, making it suitable for most patients.

The Challenge: Anatomical Variations and Concerns Over Alignment

However, this one-size-fits-all practice has been challenged by several studies that highlight the considerable anatomical variations in the distal femur among individuals. Research by Mullaji et al. (18701244) demonstrated differences in the axial femoral relationships between Asian patients with varus osteoarthritic knees and healthy knees, implying that a fixed angle may not adequately restore the mechanical axis in certain populations.

Moreover, a radiographic study by Bardakos et al. (17823023) found that a fixed valgus resection angle might not restore the mechanical axis in all cases of TKR. Their findings suggest the need for individualized planning and execution during surgery to cater to a patient’s unique anatomical structure.

Personalized Approach to DFCA: The Current Trend

These concerns have sparked a shift toward a personalized approach in determining the DFCA during TKR. Patient-specific instrumentation (PSI) and computer-aided design and manufacturing have gained popularity, allowing for preoperative planning based on the individual’s anatomy. This patient-tailored strategy aims to improve implant alignment and function, potentially reducing the incidence of postoperative complications.

The Balance Between Standardization and Individualization

In light of these discussions, there is a growing consensus that while fixed angles can be suitable for a broad range of patients, they might not be optimal for everyone. Finding a balance between the ease and efficiency of standardization and the purported benefits of individualized techniques is a key concern for the orthopaedic community.

The Role of Technology in Advancing TKR Precision

Advancements in imaging and surgical technology, such as 3D modeling and computer navigation, are offering new avenues for precision in determining the DFCA tailored to a patient’s knee. These technologies facilitate more accurate assessments of individual anatomy, potentially leading to better outcomes and patient satisfaction.

Impact on Patient Outcomes and Health Economics

The repercussions of these debates on the DFCA extend beyond surgical practice to patient outcomes and the economic aspects of healthcare. Accurate alignment is associated with prolonged implant survival, reduced need for revision surgeries, and improved patient quality of life.

Future Directions in Research and Practice

Further research is needed to solidify the evidence on the efficacy of personalized DFCAs compared to the fixed-angle approach. Studies focusing on long-term outcomes, patient satisfaction, and cost-effectiveness will help guide practice and policy-making.

Conclusion

The debate over whether a fixed distal femoral cutting angle is still justifiable in total knee replacement lingers on, reflecting one of the many challenges in achieving optimal outcomes in orthopaedic surgery. This advocates for a nuanced approach that respects individual anatomical differences while leveraging technological advancements to enhance surgical precision.

Keywords

1. Total Knee Replacement
2. Distal Femoral Cutting Angle
3. Surgical Alignment in TKR
4. Personalized Orthopaedic Surgery
5. Patient-Specific Instrumentation

References:

1. Vaishya, R., Vijay, V., Edomwonyi, E. O., & Agarwal, A. K. (2018). Fixed distal femoral valgus cutting angle is still justifiable in total knee replacement. Journal of Clinical Orthopaedics and Trauma, 9(2), 112–115. https://doi.org/10.1016/j.jcot.2018.11.001
2. Mullaji, A. B., Marawar, S. V., & Mittal, V. (2009). A comparison of coronal plane axial femoral relationships in Asian patients with varus osteoarthritic knees and healthy knees. The Journal of Arthroplasty, 24(6), 861–867. https://doi.org/10.1016/j.arth.2008.07.008
3. Bardakos, N., Cil, A., Thompson, B., & Stocks, G. (2007). Mechanical axis cannot be restored in total knee arthroplasty with a fixed valgus resection angle: a radiographic study. The Journal of Arthroplasty, 22(6 Suppl 2), 85–89. https://doi.org/10.1016/j.arth.2007.04.012
4. Response to: “Is fixed distal femoral cutting angle still justifiable in total knee replacement?” Letter to editor. (2019). Journal of Clinical Orthopaedics and Trauma, 10(3), 635. https://doi.org/10.1016/j.jcot.2018.11.001