Hip Arthroscopy

Hip arthroscopy is a type of minimally invasive surgery in which the inside of the hip joint can be examined and sometimes treated.

In the early days it was believed that the structure of the joint would mean it was impossible to use this technique on the hip joint. In contrast the knee joint was ideally suited to it. The major problems with accessing the hip joint is that it is deeper and the ball and socket joint make it less accessible then the hinge joint that forms the knee.

The breakthrough came when the significance of the way the joint is held together was understood. The hip is not just held together by its shape and the surrounding soft tissues (muscles and ligaments) but also by suction.

Once access to the joint became possible then arthroscopic surgery of the hip took off.

Arthroscopy Procedure

Hip arthroscopy is usually performed under a general anaesthetic. To start with traction is applied using a tool called a distractor. This pulls the leg (traction) and opens up the hip sufficiently to allow a needle to be inserted into the joint. Once the needle is in place the pressure inside the hip is equalised with the atmospheric pressure and at that point the hip opens up giving access to the central compartment.

The central compartment is the area between the femoral head (the ball) and the acetabulum (the socket). The surgeon may also work in the peripheral compartment which is inside the joint but outside the hip socket. Accessing the peripheral compartment doesn't require traction. The hip can be put back into place and the hip bent slightly to allow the soft tissues on the front to relax. This allows sufficient space to work.The next stage is to make two (possibly three) incisions - one for the arthroscope itself and one (or two) for the surgical instruments.

Arthroscopy instruments are made in smaller sizes then those generally used and include manual cutters, radiofrequency probes and powered shavers and burrs.

An arthroscope is made up of a tube with a group of lenses, a light (to allow the surgeon to see) and a video camera which sends a signal to a monitor. This video stream is the only view the surgeon has of the surgical site.

The arthroscope itself is about 5mm in diameter.

What is it for?

Hip arthroscopy can be used to deal with many different joint problems.

Torn labrum - the ragged edges of a torn labrum can be trimmed back to leave healthy tissue
Loose bodies - any loose bits of cartilage or bone can be removed. Flaps of cartilage (associated with arthritis) can be debrided (removal of dead or damaged tissue) - thus delaying the process of the disease.
Femoracetabular impingement - this is where the head of the femur and/or the acetabulum are misshapen causing damage within the joint. In some cases this can be dealt with arthroscopically.
Biopsy - removal of a small amount of tissue for analysis.
Repair of joint tissues such as ligaments
Diagnosis - sometimes it is necessary to see into the hip joint itself to reach a diagnosis.

Advantages

The minimally invasive approach means the joint doesn't have to be opened up fully.
Recovery times are much quicker
The patient can often mobilise and go home on the same day
There is less trauma involved
There is less damage to surrounding tissue
There is less scaring
The outcome is usually good but does depend on what the problem being treated is

Risks of Arthroscopy

The irrigation fluid used to distend the joint (to allow sufficient surgical space) may leak into the surrounding tissue causing either an oedema (literally swelling caused by fluid in the tissues. or extravasation (leakage of fluid)
There may be some numbness in the perineal area but this will wear off within days - in some cases may last a few weeks.
Despite advances in techniques it is sometimes not possible to open up the hip joint this way

Conclusion

The development of hip arthroscopy has been a real boon for people with hip problems. The procedure is used both for diagnosis and treatment and can delay, or even prevent, the need for more invasive procedures such as a total hip replacement.

The process is a complex one and can take longer than a full blown total hip replacement.

There are a number of arthroscopy videos available on youtube.com which are aimed at medical students and can be difficult to follow. Here's a great one - it focuses on labrum tears but will give you a really good feeling for the procedure.