In patients with a complete tear or rupture of a ligament or other soft tissue, the surgeon is able to pass the arthroscope right through the space between bones or joints. This is commonly referred to as the drive-through sign.
In any joint, a positive drive-through sign is diagnostic of multidirectional joint laxity or instability. Surgery is required to repair the damage and restore joint stability and function.
Repair may be possible arthroscopically at the time of the arthroscopic exam. Sometimes the surgeon completes the exam and then performs an open procedure to repair or reconstruct the damaged area.
It sounds like that’s what happened in your daughter’s case. Using arthroscopy to make a definitive diagnosis is important in choosing the right treatment for the problem.