ACL injury

A 36 year old male came in today for evaluation of his left knee. Patient is concerned about preventive care and avoiding future arthritis, surgeries and possible total knee replacement He states about 3 years ago while skiing he had a fall. At that time it was very painful and he needed emergency personnel to bring him down the slopes using stretcher. He had an MRI initially that showed partial tear of his ACL (Anterior Cruciate Ligament). Patient had some physical therapy and he was able to get some self healing subsequently. At this point he says he can not run (knee feels unstable), and at times if he swims a lot he gets some discomfort. He is otherwise healthy and does not take any medications.

Discussion: There are four ligaments holding the knee in its place, one at each side (collateral ligaments) and two crossing over in the middle (Cruciates). The Cruciate ligaments stop the bones sliding forwards and backwards. Typically ACL gets injured through twisting the knee by a forceful motion. Pain and swelling usually are the cardinal manifestations of the tear. The best way to diagnose is doing an MRI. Also the Lachman Test (see above picture) which can be done during physical exam by which, the examiner Bends the knee to about 30 degrees. Then, stabilizing the femur with one hand, placing the other hand behind the proximal tibia (shin bone) at the level of the joint line and then pulling the Tibia forward, noting degree of anterior Tibial displacement, and looking for instability, can help while diagnosing the ACL tear.

The Knee shown from front; Normal anatomy of ACL can be seen at the center of the knee.

Case Study Date: 8/17/2007