The Mechanics of Orthopedic Surgery

Try to make this out: "A guide pin is drilled from medial to lateral exiting at the tibial posterolateral corner and it is then overdrilled with a cannulated 6.5-mm diameter reamer. A Beath needle is passed from medial to lateral, pulling the semitendinosus tendon to the posterolateral aspect of the knee." Knee! Now there's a word we can recognize!

This sounds like a manual for an auto mechanic. But it's really a technical note from a surgeon explaining a new method for knee surgery. Doctors, like mechanics and other workers, report to one another methods that work and how to do them. The above instructions are part of a step-by-step guide for an uncommon knee problem in orthopedics.

Knee injuries that produce too much looseness in the back, outer rim of the knee joint are challenging to repair. This condition is called "posterolateral instability." Injuries to the knee during contact sports are the most common cause of this type of instability. Typically, two ligaments deep within the joint tear. These are the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL). Sometimes only one ligament is torn, along with other supportive structures.

To make this diagnosis, the doctor must carry out a very detailed exam. It is necessary to study the way the patient walks and performs many special tests. Which tests are positive tells the doctor where the injury is located. Imaging studies are needed to make a final diagnosis. These may include X-rays and magnetic resonance imaging (MRI).

Surgery for this type of knee instability is long and complex. Sometimes it isn't possible to finish the job in one operation. The surgeon may repair the PCL, along with the structures around the back of the knee. The ACL is repaired at a later date.

"A guide pin is drilled in the anatomic insertion of the popliteus and lateral collateral ligament, the tendon is folded over itself, and a firm stump with the 2 components of the fold is made with a nonabsorbable suture." Let's leave joint repairs to the experts. At least they can read the manual!



References: Jorge A. Santander, MD, et al. Chronic Posterolateral Instability of the Knee: A New Surgical Approach. In Arthroscopy. February 2002. Vol. 18. No. 2. Pp. 214-217.