Original articleThe Variability of Intramedullary Alignment of the Femoral Component During Total Knee Arthroplasty
Section snippets
Methods and Materials
Seven cadaveric lower extremities were used for the study in 4 cadaveric bodies. One lower extremity could not be used because of the existence of a previous total knee arthroplasty. For each lower extremity, a standard midline incision was made and medial third parapatellar approach to the knee used to attach anchoring pins in the femur and tibia for attachment of infrared emitters, per manufacturer's instructions (Stryker Navigation, Kalamazoo, Mich). A pelvic anchoring pin was also placed 2
Results
A significant difference in flexion of the intramedullary rod was recorded for the anterior and posterior starting points. The anterior starting point on average resulted in −2.2° ± 1.4° (representing recurvatum of the femoral component) compared with the mechanical axis, and the middle starting point resulted in 1.9° ± 2.2° of flexion compared with the calculated femoral mechanical axis by the computer-assisted surgery system (Fig. 2A). The posterior starting point resulted in 3.8° ± 2.6° of
Discussion
A misaligned primary TKA may result in an earlier than expected revision. The use of intramedullary alignment has greatly improved the coronal plane alignment of femoral components and helped to increase the long-term survival of a total knee arthroplasty. However, as the present study showed, the coronal plane is not the only one in which a femoral component alignment problem may occur.
Our data clearly demonstrate that entry point deviation of just 5 mm anteriorly or posteriorly may result in
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Systematic effects of femoral component rotation and tibial slope on the medial and lateral tibiofemoral flexion gaps in total knee arthroplasty
2020, Journal of Orthopaedic TranslationCitation Excerpt :Arthroplasties are typically performed with the goal of reducing pain, correcting deformities and improving functionality, and outcomes are influenced by several factors, including sex, age, body weight, surgical indication, surgical technique, technical equipment and surgeon skills [3,4]. Moreover, the orientation of the prosthetic components plays a critical role in the lifetime of a prosthetic implant [5]. The poorer outcomes of knee arthroplasties compared with hip arthroplasties [6] are presumably related to the greater complexity of the anatomy and consequently the biomechanics of the knee compared to the hip.