Mosaicplasty of the knee joint

One part of the causes of isolated cartilage damage and demise in the knee joint is unknown. The cause may also be induced by a local circulatory issue, or injury. Sometimes develops as a consequence of repeated microtraumas. The abnormality most commonly causes pain, which mainly presents during loading, but pain at rest may develop too. Sometimes the joint swells up, and partial or a complete obstruction (joint lock) may occur during movements. Rarely, the small, demised bit of bone and cartilage is ejected from its place, and as a loose body, it may cause pain or obstruction at different places. The disease can often be visualized well by an X-ray scan only, but sometimes an MRI scan is necessary to accurately detect and locate it.

What are the treatment options?

Non surgical treatment

During the investigation, it is necessary to do an X ray scan in addition to physical examination. An MRI scan may become necessary if no changes are revealed. Once the diagnosis is made, it is important to reduce the loading of the knee, to suspend physical labor or sport activities, especially those which involve movements with change of direction. Taking non steroid anti inflammatory drugs is recommended if the knee is swollen. This may be complemented by various physical therapy treatments. Surgical treatment is selected if the treatment does not improve the symptoms.

Surgical treatment

A closed intervention is performed if the abnormality can be safely accessed and treated by an arthroscope. If this is not an option due to poor accessibility, an open, exploratory surgery is performed. During surgery, small cylinders of cartilage and bones are removed from the non weight bearing areas of the knee joint, which are covered by healthy cartilage, and these are transferred to the defective loading area in a mosaic like manner. Unfortunately, this method is only suitable to replace the cartilage in an area of a certain size, usually of 2x2 cm i.e., 4 cm2. Exercises may already be started on the next day, depending on the instructions of the treating physician, and the physiotherapist. Complete non weight bearing of the operated limb is recommended after the surgery for 4-6 weeks, which is followed by 2-4 weeks of partial weight bearing according to the instructions of the physician, who performed the surgery. However, knee movements must be started immediately after surgery. It is recommended that you do the practiced physiotherapy exercises at home, and you refrain from putting weight on the operated limb, as needed.

In non problematic cases, the patients are discharged home on the first day after surgery.

What happens during the surgery?

During an arthroscopic surgery, 2-3 small incisions with a maximum of 1 cm are made in the knee joint. This is followed by locating the defect and cleansing its edges from the damaged pieces of cartilage. Measurements are taken of the defect, and usually from the patellar femoral joint surface, so from the so called non loading surface, bone cylinders covered with cartilage are removed in an adequate number and size with a special toolkit, then these are placed on the defected area. The size of the bone cylinders or “grafts” are determined in a way that they cover as large an area as possible of the defect in a mosaic-like manner.

In case of an open surgery, skin incisions of a few cm are made usually in those locations, from where it is the easiest to access the defect according to the professional principles. After exploration, the defect is located, and its edges are cleaned from the damaged pieces of cartilage. Measurements are taken of the defect, and from the patellar-femoral joint surface, so from the so called non loading surface, bone cylinders covered with cartilage are removed in an adequate number and size with a special toolkit, then these are placed on the defected area. The size of the bone cylinders or “grafts” are determined in a way that they cover as large an area as possible of the defect in a mosaic-like manner. Surgical hemostasis is performed after the surgery, and the wound is closed in layers. The “areas of bone loss”, from where the removal was done, usually fill up in a few weeks after the surgery, and they will be covered with fibrous cartilage. Although, the loading capacity of these is smaller, but it will not cause any symptoms, because significantly smaller loads affect these surfaces. A drain is inserted into the joint, so that the discharge and residual bleeding which accumulated after the surgery could be removed. Elastic bandage is applied on the patient’s leg from the foot to the thigh.

What happens if the justified surgical treatment is not performed?

The pain will persist causing additional subjective inconveniences, or potential difficulties in movement. Joint wear is typically accelerated, and this process becomes irreversible after a while. Surgical treatment holds out smaller success if it is done after a chronic, long term inflammation.