Injections

The most commonly used injections into the knee are of steroid and of a shock absorbing substance called hyaluronic acid. Biological injections such as PRP and Lipogems can also be used. See this website for more information. Injections into the knee carry a small risk of introducing infection and should therefore be performed in aseptic (very clean) surroundings and with an aseptic technique.

Hyaluronic acid can be used in early arthritis to improve the shock absorbing and health of the cartilage that is still intact. It generally entails a single injection into the knee and the success rate is good but not 100%. The period of relief of symptoms gained is also variable and ranges from days to years.

Steroid is very commonly used as it is a potent anti-inflammatory drug. However there is evidence that steroid increases the risk of infection after joint replacement surgery and increases the speed of progression to a joint replacement.  As such, in Mr Shepard’s opinion, should only be used in inflammatory arthritis or in advanced cases of arthritis when the patient is unfit for joint replacement.

Osteochondral Grafting

Osteochondral grafting is a procedure designed to treat defects in the articular cartilage lining if the knee joint. In this procedure a tunnel of bone is cored out of the base of the defect and a matching core of bone and cartilage is taken from a part of the knee where there is no actual joint between bones. The core of cartilage and bone is then impacted into the tunnel drilled in the base of the defect. The cartilaginous defect may be filled with articular cartilage attached to a bone block that heals to the sides of the tunnel providing support for the cartilage graft. This procedure is performed arthroscopically.

Microfracture

Microfracture chondroplasty is a procedure pioneered by Dr Richard Steadman in the US and is a treatment for defects in the articular cartilage surface of the knee joint. It is an arthroscopic procedure in which small controlled fractures are made in the base of the defect using sharp “picks”. Bleeding then occurs into the defect and a clot forms which over the course of several weeks becomes “organised” into cartilage.

A further advance in this procedure is to combine the procedure with a collagenous matrix which protects the clot allowing earlier mobilization of the knee. This procedure is called AMIC.

Autologous Cartilage Transfer

Autologous chondrocyte transfer is a treatment for defects in the articular cartilage that lines the joint. It involves taking a sample of normal cartilage from inside the knee and sending it to a lab to be cultured. Here the cells are multiplied in the culture before reimplantation into the knee under a flap of membrane that is sutured over the defect. The cells then implant into the area producing a new articular cartilage covering to the bone.