The JBJS Quiz of the Month is a collection of 10 relevant questions from each orthopaedic subspecialty. The questions are drawn from JBJS Clinical Classroom, which houses over 4,500 questions and 3,100 learning resources. Take the Quiz to see how you score against your peers!

NOTE: This quiz does not earn users CME credits. The questions must be answered within Clinical Classroom to earn CME credits.

A 59-year-old female patient with varus arthritis with 6 years of antecedent pain undergoes a fixed-bearing medial unicompartmental knee arthroplasty. Which of the following best describes the purpose of slightly undercorrecting her coronal plane deformity when cutting the extension spaces of the femur and the tibia?
    • Improve patellofemoral mechanics of the native joint
    • Overall varus alignment of the limb usually has some degree of medial patellofemoral wear. Straightening out of the limb with the correction usually unloads the medial aspect of the patella. Avoiding overloading the lateral compartment is the primary aim of slight undercorrection of the coronal plane.
    • Mimic the ideal goal of kinematic coronal-plane alignment
    • Avoiding overloading the lateral compartment is the primary aim of slight undercorrection of the coronal plane
    • Increase fixation strength of the tibial component, which is typically the weakest fixation point in cemented unicompartmental knee arthroplasty
    • Aseptic loosening is the most common mode of failure and this more commonly effects the tibial component rather than the femoral component. Avoiding overloading the lateral compartment is the primary aim of slight undercorrection of the coronal plane.
    • Avoid overloading of the lateral compartment
    • To avoid advancement of the lateral compartment and failure of the partial knee replacement, slight undercorrection in the coronal plane will avoid overloading the lateral compartment

     

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