Hip Arthroscopy

Hip arthroscopy is a surgical procedure used to diagnose and treat problems of the hip joint and surrounding soft tissues.  This is done though small incisions, allowing rapid recovery.  This technique has meant that experienced surgeons can now treat conditions that were not amenable to surgery before without significant risks and rehabilitation.

shutterstock_1319312795.png

Conditions commonly treated

 

Hip Impingement and the treatment of Labral Tears

Removal of Loose bodies

Sometimes early arthritis can respond to hip arthroscopy. 

Acetabulum edited.png

Labrum - a triangular section of cartilage running around the outside of the socket

Ligamentum teres

Hip Impingement

Hip impingement syndrome is caused by unwanted contact between abnormally shaped parts of the femur and the hip socket (acetabulum).   This can result in symptoms of pain, and can lead to arthritis.  Some people have these abnormalities, but have no symptoms or problems.  If you are one of these people, then these abnormalities are unlikely to need treatment.

If you have symptoms, physiotherapy can help in many cases. 

A guided steroid injection is often used to help confirm the diagnosis.

There is now evidence that if you have symptomatic Femoro-Acetabular impingement, that more patients will have better outcomes with surgery than with physio and activity modification alone

https://www.bmj.com/content/bmj/364/bmj.l185.full.pdf                                                                                                                                       

Hip outline
normal flexed.png

Acetabulum

Labrum

Femoral Head    Neck

Normal Hip

This is a representation of a normal hip shape. When the hip flexes the neck of the femur approaches the labrum, but never compresses it.

CAM neutral.png
CAM flexed.png

CAM lesion

CAM impingement

Sometimes there is extra bone around the front and top of the femoral head / neck junction - the CAM lesion

If you follow the contour of the femoral head, you can see it is round, then it becomes straight, just like in the X-ray of the patient below.

When the hip flexes and rotates, the CAM engages the edge of the socket, catching the labrum. This can tear or get damaged.

pincer neutral.png
pincer flexed.png

Pincer lesion

Pincer  impingement

There may also be extra bone around the front of the acetabulum, deepening it's wall

Now, when the hip flexes and rotates, the femoral neck can again damage the labrum

These examples are simplified. Hip impingement can have a mixture of both CAM and pincer, as well as other causes.

Cam x-rays 1.png
Cam x-rays 2.png
CAM lesion

 

This X-ray picture is off patient who had CAM impingement in both of his hips.  If you look at the left hip, (on your right hand side of the picture)  you can see the CAM lesion. If you hover your cursor over the image, the CAM lesion will be highlighted. 

 

This patient had the same problem on their right hip, and underwent surgery on it to remove the CAM.  You can see a more normal / rounder appearance of the femoral head.   

                                                             

 

Does Hip Impingement always need surgery?

No.  Many patients only have minimal symptoms, and don't need any surgery.  Even paients with symptomatic impingement often respond to physiotherapy and lifestyle changes - ie avoiding the movement that causes the pain.

Sometimes a steroid injection can reduce the symptoms of hip impingement.  Usually your surgeon will make sure that everything has been tried before recommending surgery.

What is a Labral Tear?

The labrum is a horseshoe-shaped ring of cartilage that surrounds the acetabulum.  It has many functions, including joint position sense, cartiage nutrition and stability of the hip.  It can be torn through impingement, repetitive stress, trauma, or arthrthritis and ageing. Sometimes abnormally shaped hips  or hypermobility can predispose to labral tears.

acetabulum with tear.png

Labral tear

The labrum can be torn from its attachment, becoming unstable.  This often causes a catching or pinching pain, especially on certain movements.  Sometimes the torn labrum can get stuck in the joint, causing a feeling that the hip is going to give way.  In general, a torn labrum will give pain only when it is stressed.  There will be periods of time when the pain goes completely.

Sometimes the labrum tears as part of osteo-arthritis.  It is usually the arthritic joint, and not the labrum that causes the most pain.  Arthritic pain tends to be more constant.

A labral tear is often diagnosed on an MRI, following a patient consultation.

This MRI scan shows a labral tear. It can be difficult to see, but there is a faint white line between the acetabulum and the labrum

Cam MRI 1.png
Cam MRI highlighted.png

Acetabulum

Labrum

What happens during surgery?

The patient is anaesthetised either by a general anaesthetic or by a spinal.

Some patients who have spinal anaesthetics want to be completely awake, to watch the procedure. Most however, want to be asleep, so they don't know what is going on.

On a special operating table, the feet are placed in boots and a memory foam post is put between the legs.  Traction (a pulling force) is applied until the hip subluxes - which means separates from the joint by around a centimeter.  

Using X-ray, the surgeon firstly inserts needles into the hip, to make sure that they can get in without damaging other structures.

A special long ifibre-optic camera and struments are carefully inserted into the hip. Parts of the hip capsule have to be cut in the front of the joint.  The surgeon will look around the hip, identify problems and treat what they can. 

Bony lumps (such as CAM or pincer lesions) can be removed using high speed burrs.  The labrum can be repaired by stitching it back onto small anchors.  Loose bits of bone / tissue can be removed.  Early arthritis can be cleaned up.  Sometimes , damaged cartilage can be replaced with microfracture or AMIC.

If the labrum is irrepairable, the damaged area can be cut back to healthy tissue.
 

How should I choose a surgeon?

Hip arthroscopy is a difficult procedure.  Surgeons should be performing a minimum of 30 per year to maintain their skills.  They should be reviewing and recording their results in accordance to NICE guidance (ipg408).

 

There is a national rdatabase / registry for these procedures (The Non- Arthroplasty Hip Register) , making sure that the surgeon's results are being recorded and audited. You can check if your surgeon is participating by using this link, and scrolling down to where it says ,'Search Our NAHR Members'. 

 

It is highly recommended to ask your surgeon what proportion of Labral Tears they fix. Many surgeons are able to do a basic hip arthroscopy, but they do not have the skills / experience / instruments required to fix a torn labrum.  E.g. most hip arthroscopists in Sussex (apart from Mr Langdown, Mr Stott and Mr Velayudham) will excise the torn labrum, rather than fixing it.  This is a much quicker and easier procedure than saving the damaged labrum.

NAHR.png
Hip arthroscopy

This image is an  X-ray itaken during the patient above's right hip arthroscopy. You can see the hip has been distratced and the first needle has been inserted/

FAI CAM x-ray

In this image, a small hole is being drilled around the edge of the socket, to insert an anchor to repair the torn labrum.

What is the recovery like?

As you can see, hip arthroscopy procedures vary in complexity and time depending on how much has to be done inside the hip.  Recovery varies from patient to patient, up to 6 weeks if there is microfracture.  Most people are on crutches for around four weeks, although they can put full weight on the leg from day one.. If the labrum has been repaired, the patient should not flex their hip beyond ninety degrees for six weeks.

Driving is usually possible by four weeks.  The surgery can be very painful for the first few days. This usually decreases ater day three.  At six weeks the pain is usually less than it was pre-op.  Most of the recovery has happened by three months, but patients often continue to improve until eighteen months.

What are the results of hip arthroscopy?

This procedure has been proven to be effective in treating labral tears, loose bodies, cartilage damage and hip impingement. It is backed by NICE.  There is a patient information leaflet available here

Generally  80% of patients report good to excellent improvement, 15% of patients say that the procedure has not helped, and 5% of patients get worse.

The patients who have poorer results usually have one or more of

  • more arthritis

  • the problem has been around for a long time,

  • older age group

  • have other problems such as knee or back pain

 

In Mr Stott's experience, nearly every patient that has problems with both hips, has one side done, and comes back for the second side to be treated too.  

What are the risks?

Overall the complication rate of hip arthroscopy is low at around 4%.  Complications can include:

Ongoing symptoms

When there is damage to the joint, this can cause pain even when it is fixed.  Despite repairing the labrum, it is not possible to make it as good as new.  The hip capsule is cut during the procedure, and this can cause an impingement type pain until it heals.  Sometimes people have groin pain from other causes, such as muscle problems (especially hip flexor). These muscle issues can be aggravated by the surgery. 

 

After removing the CAM or pincer lesion, the surgeon can move the hip around to check that there is no further impingement, however, the hip can only be flexed to just past ninety degrees.  Impingement can still occur in extreme flexion / rotation.  Most surgeons (including Mr Stott) are conservative and try and take what they judge is the right amount of bone away.  It is better to take too little, than too much, as taking too much can have disastrous complications - see fracture /  dislocation and avascular necrosis.  Rarely, a patient will come back with ongoing signs of impingement, and need more bone removing.

Nerve damage

The commonest nerve to be damaged in hip arthrosopy is the lateral cutaneous nerve of the thigh. (up to 20% of patients) This nerve supplies the outside of the thigh. It runs very close to the incisions which are made around the hip.  If it gets damaged it usually recovers, but there are reports of it being cut.  Nerves can also be damaged by the post between the legs,  causing damge to the nerves affecting the genitalia (1 to 2% of patients). If this happens it produces numbness in the labia in women, and the tip of the penis or scrotum in men.  It usually recovers in six weeks.  Very rarely, the major nerves to the leg can be damaged by pulling on the leg during distraction (femoral or sciatic).   This is a disastrous complication, but thankfully extremely rare

Pressure damage

Obviously some force is required to distract the hip. This force can cause bruising or damage where the traction boots and groin post are.  Some patients have foot /ankle / knee / groin  pain or swelling following surgery.  This is more common if there are pre-existing conditions affecting that leg, e.g. ligamentous damage in the knee.

Failure

Sometimes it is not possible to safely distract the hip joint.  When this happens, it is not possible to get  into the hip to do the procedure without causing damage.  The surgeon's main objective during the procedure is to do no harm to the patient. Sometimes, it is possible to remove parts of the CAM lesion when the surgeon cannot get into the hip.

Rarely the labral tear does not heal, or the anchors pull out if the hip is subject to trauma.

Cartilage damage / arthritis

It is possible for the surgeon's tools to damage the cartilage within the hip.  This can cause arthritis or pain. However, impingement lesions are often associated with cartilage damage (arthritis).  Once arthritis starts, it often progresses no matter what is tried.  Ironically taking off the impingement lesions can actually speed up arthritis, as the joint will have a greater range of motion.

Recurrence

It is possible to re-tear a labrum.  Bone lumps can grow back. 

Infection

Infection is a rare complication of hip arthroscopy, around 1 in 1,500 .  Infections usually appear around ten days post-operatively, and cause significant pain and a fever.  If this happens, the patient must attend their local emergency department immediately.

General anaesthetic risks, including Deep Venous thrombosis

Fracture and dislocation

If too much bone is removed from the femur or the patient resumes impact activity too soon the femur can fracture (around 1 in  1000). If too much bone is removed from the acetabulum, it is possible to dislocate the hip.

Instability

The hip is a relatively stable ball and socket joint. However, some patients have pain from the hip due to it coming out of its joint. During a hip arthroscopy, some of the hip capsule is cut.  This can cause pain post-operatively, especially in females, patients with hip dysplasia or hypermobility.

 

Avascular Necrosis

Rarely (around 1 in 1000) the blood supply to the hip can be interrupted during the operation.  This can cause the bone in the hip to undergo necrosis (tissue death).  This can be temporary or permanent. If it progresses it will need a hip replacement.

Extra bone growth (Heterotopic ossification)

Islands of bone growth can occur around a treated hip, or in the tracks that the instruments make.  This rarely causes any symptoms or problems.

Further information can be found here