What is a typical pattern of knee effusion after a meniscal injury?

What is a typical pattern of knee effusion after a meniscal injury?

• A. Immediate swelling within hours
• B. Delayed effusion 6-24 hours
• C. No effusion
• D. Swelling after 3 days

Answer: (B)

Knee effusion after a meniscal injury is typically delayed rather than immediate. The tear irritates the joint lining and triggers an inflammatory response, leading to fluid accumulation over hours rather than a brisk bleed into the joint. Because the meniscus has limited vascular supply, especially away from the outer edge, there isn’t a rapid, large amount of intra-articular blood unless other structures are injured. As a result, swelling often becomes noticeable around 6 to 24 hours after the injury. Immediate swelling is more characteristic of injuries that cause brisk hemarthrosis, such as ACL tears or fractures, while swelling after several days is less typical. Hence the usual pattern is a delayed effusion within roughly 6–24 hours.

Knee effusion after a meniscal injury is typically delayed rather than immediate. The tear irritates the joint lining and triggers an inflammatory response, leading to fluid accumulation over hours rather than a brisk bleed into the joint. Because the meniscus has limited vascular supply, especially away from the outer edge, there isn’t a rapid, large amount of intra-articular blood unless other structures are injured. As a result, swelling often becomes noticeable around 6 to 24 hours after the injury. Immediate swelling is more characteristic of injuries that cause brisk hemarthrosis, such as ACL tears or fractures, while swelling after several days is less typical. Hence the usual pattern is a delayed effusion within roughly 6–24 hours.