STIFF TOTAL KNEE
The stiff total knee is also a painful total knee, because the tight, unyielding soft tissues are under stress during everyday activities.
What destines the range of movements in the total knee:
There are usually more than one factor that causes that the total knee joint will be stiff after surgery.
A) The most important factor that determines how much you will be able to bend your new total knee is the preoperative range of motion in your knee. If the range of motion in your knee was low before the operation, the range of motion in your new total knee joint will improve, but you cannot expect that you will have normal range of motion after total knee surgery.
B) Another important factor is the correct placement of the total knee prosthesis.
Picture
Stiff total knee - some of the causes
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A: normal knee
In normal knee joint the patella (kneecap) is placed above the joint line;
the stretching (extensor) apparatus has the right tension and lengthens when the knee bends.
the PCL (posterior cruciate ligament has the right tension and allows bending of the knee joint
B: stiff total knee joint
In a stiff total knee joint the prosthesis is placed too high, so that the patella is too low -the new joint line touches the patella.
The faulty position of the total knee prosthesis increases the tension in the extensor apparatus which cannot lengthen during the knee bending. Besides, there is also a tight scar in the extensor musculature, that further hinders the lengthening of the musculature during knee bending.
The PCL is tight and hinders the bending of the new knee joint.
Patients with previous knee surgery are at greater risk for stiffness in their total knee.
If your new total knee is stiff (less than 90 degrees of flexion) although you have had a good range of motion in your knee before the operation and if the X-ray picture shows that the total knee prosthesis is placed correctly, then a manipulation of your knee under narcosis may be considered.
Usually, the total knee joint which bends less than 90 degrees after 2 - 4 weeks of intensive postoperative rehabilitation is the candidate for manipulation in narcosis.
The manipulation under narcosis may be done under the first three postoperative months. Later on, the soft tissue scares have matured and the tissues cannot be stretched passively.
The frequency of the manipulation in narcosis after a total knee operation varies in different reports between 0 % to 20 %. Some reports maintain that the use of CPM apparate diminishes the rates of manipulation in narcosis.
The results of manipulation in narcosis (in one report) demonstrate improvement from 67 degrees of knee flexion before the manipulation to 111 degrees after the manipulation. At one year the knee manipulated in narcosis have had equally good flexion (111 and 114 degrees) as the patients who did not need the manipulation, respectively. The satisfaction of the patients who had knee manipulation was equally high as the the satisfaction of other patients (Maloney 2002).
The manipulation in narcosis carries with it the risk of fracture of the skeleton around the total knee.
It is also possible to remove the scars in the joint capsule and soft tissue by operation. The surgeon may use only a key hole access (arthroscopy) for the operation.
In rare cases, the surgeon may use a broad operative access to the total knee to remove all scared tissues and possibly also exchange the total knee joint if it is in faulty position. (Christensen 2002)
References
Maloney WJ J Arthroplasty 2002;17 (Suppl): 71-3
Christensen et al J Arthroplasty 2002;17 : 409 -15
Kim et al.: Stiffness after total knee arthroplasty J Bone Joint Surg-Am 2004; 86-A:1479 -84
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