While modern surgical procedures can repair or replace a faulty knee joint, some patients may continue to hear cracking or popping noises or feel a “catching” sensation in the knee after recovering from the procedure. These noises or sensations may be a complication from the procedure or a natural part of the new joint function.
As the largest joint in the human body, the knee contains many delicate structures that can easily suffer damage through injury or wear. Popping, clicking or a feeling that the knee is "catching" can indicate the need for knee surgery, especially if the sufferer also feels pain or the knee gives way under weight-bearing conditions.
Knee surgeries vary in complexity and scope. X-rays and a process called magnetic resonance imaging (MRI) can help a surgeon determine which parts of the knee require surgery. Smaller procedures may call for arthroscopic surgery, in which the surgeon works through a small cut while viewing the details on a video monitor. Repair or replacement of a single ligament or cartilage may restore stability and strength to the knee. If the knee is severely damaged, however, the surgeon must replace the joint with a prosthetic (artificial) joint. Arthroscopic surgery patients can usually go home after only one to two hours in the recovery room.
A clicking or cracking sound in the repaired knee may not indicate any problems or surgical failure. In most cases, some noise in the knee continues to occur as a natural result of the procedure. In a knee replacement, for instance, the metal and plastic components of the prosthetic implant may come together or spread apart as weight is transferred to or from the joint, causing a clicking or cracking sound. A rarer condition called patellar clunk syndrome can also cause noise following knee replacement surgery. In this case, scar tissue forms toward the top of the kneecap and then “catches” on a metal groove in the implant whenever the knee bends. Unlike most cases of knee cracking or popping, patellar clunk syndrome also causes pain.