American Board of Internal Medicine (ABIM) Certification Practice Exam

What does lateral joint line tenderness during examination suggest?

1. Patellar tendinitis

2. Complete medial collateral ligament tear

3. Complete lateral collateral ligament tear

4. Quadriceps strain

The correct answer is: Complete lateral collateral ligament tear

Lateral joint line tenderness during an examination is indicative of potential issues with structures located on the lateral aspect of the knee. Specifically, this tenderness often suggests a problem with the lateral collateral ligament (LCL) or injuries to the structures adjacent to the lateral joint line of the knee. In the context of a complete lateral collateral ligament tear, the presence of lateral joint line tenderness would be a direct sign of an injury to this ligament. The LCL supports the outer side of the knee and helps to stabilize the joint against varus forces. When it is torn, patients frequently experience tenderness on the lateral aspect of the joint, along with potential instability and swelling. Additionally, while other conditions, such as patellar tendinitis, complete medial collateral ligament tears, and quadriceps strains, can cause various symptoms and tenderness, they typically do not produce tenderness specifically localized to the lateral joint line as a primary sign. Therefore, the most fitting interpretation of lateral joint line tenderness is that it suggests a complete lateral collateral ligament tear.