Hip Arthritis

The word arthritis comes from two origins The first is “arthro”, which is Latin for joint, and the second is “itis”, which is Latin for inflammation. Combined, arthritis simply means inflammation of a joint. All joints have the ability to be inflamed and the hip is obviously no exception.

There are many causes of hip arthritis. Whilst the most common is so-called osteoarthritis, a mechanical wearing out of the joint, we also have rheumatoid arthritis, psoriatic arthritis, post-traumatic arthritis and other forms of inflammatory arthritis associated with hemosiderosis, avascular necrosis (death of the ball on the upper end of the thigh bone), ochronosis and other rare maladies. All forms of arthritis do have several common features. Typically, the hip joint becomes painful with most pain being localised to the groin. Sometimes the pain will radiate from the groin down the front of the thigh bone as far as the knee. This is due to the fact that the hip joint is supplied by one branch of the obturator nerve. It is the so-called anterior division. The posterior division runs down the thigh as far as the knee. Whilst the hip joint might be sending the painful messages back to the brain, there are times when the brain can’t tell whether it is the anterior division or the posterior division which is delivering the messages. The brain sometimes is tricked into thinking that the knee is the problem. In fact, there are well-recorded cases where patients have undergone operations on the knee when really the primary problem was in the hip!

Femoro-acetabular impingement (FAI)

The word “femoro” comes from femur or thigh bone.  The word “acetabulum” comes from the socket in the pelvis.  The syndrome arises when the upper end of the thigh bone (the femur) impinges or bangs against the edge of the acetabulum or socket.  One single impingement phenomenon is insufficient to cause serious disease.  Unfortunately, the impingement phenomenon is repetitive and protracted.  It may occur hundreds of thousands or even millions of times over a period of years.  It is the repetitive banging or impingement that causes damage both to the socket and the edge of the thigh bone.  This is a well-accepted and, unfortunately, all too common cause of osteoarthritis of the hip joint.

The symptoms are usually in the form of pain in the groin and occur with full hip joint flexion (bending the thigh up towards the torso) and with internal rotation (turning the affected knee in towards the other knee). Bike riders, hurdlers, rowers and football players often note these symptoms earlier than others not so active. The symptoms will sometimes begin in the patient’s early 20s. As the years pass, so do the symptoms become more noticeable and frequent and, similarly, there are noted restrictions in range of motion of the joint. Typically, the patient loses the ability to fully flex and internally rotate the hip.

Labral Tears

The labrum is a soft cartilaginous flange-like structure which is attached to the edge of the socket or acetabulum in the pelvis.  It would be useful if you read the preceding section dealing with femoroacetabular impingement syndrome.  We deal with the labrum there.

The labrum has several functions in the hip joint.  It does serve to deepen the socket somewhat and thereby make the ball and socket joint more stable.  In addition, it probably has some role in distributing the synovial or lubricant fluid through the joint.  It also softens the edge of the socket such that bumping or impingement may be less dramatic and painful.

When they are symptomatic, usually in the age group between 20 and 45 years, they sometimes require treatment.

Non-operative measures, apart from symptomatic relief with analgesics, are usually ineffective.  From a surgical perspective, arthroscopic re-attachment of the labrum can be very successful.  Alternatively, if the labrum is too severely degenerate, that segment may be excised or trimmed.  There is also a more recent move towards labral reconstruction.  Other tissues from the body can be used or, alternatively, we can use so-called allograft materials from cadaveric donors.  These are issues that you should discuss with us at your next visit.

Abductor Dysfunction

The abductors are muscles which arise from the outer side of the pelvis and converge in tendons down onto the upper end of the thigh bone or greater trochanter.  When the muscle contracts, tension is applied to the tendon and the upper end of the thigh bone is pulled upwards.  This, in turn, has the effect of taking the lower limb out to the side.  This is the movement called abduction.  The converse would be taking the upper limb across the midline of the body towards the other side.  That would be called adduction.  Flexion is where we pull the thigh bone forwards and extension is when the thigh bone is taken backwards.  Rotation speaks for itself.  Internal rotation is towards the other side whereas external rotation is towards the outside.

The most common is in the form of an inflammatory process or degenerative change within the tendons that insert into the upper end of the thigh bone or the greater trochanter.  We calls this abductor tendinopathy.  Sometimes partial or complete tears can occur.  The region over the greater trochanter can become painful.  A secondary bursitis often forms.

Another type of abductor dysfunction occurs when the abductor muscles themselves are weak or even paralysed.  The normal pattern of gait is no longer possible.  Instead, the patient must tilt his or her torso over the top of that hip whilst load bearing on that limb.  This is the so-called abductor or Trendelenburg lurch.

Iliopsoas Tendonitis

The iliopsoas muscle is a complex structure.  The muscular part arises from the so-called transverse processes up in the lumbar spine and they converge downwards and into the pelvis and ultimately form a tendon as the structure passes over the front of the pelvic rim.  That tendon then courses down and medially in the thigh and inserts onto a small bump on the upper end of the medial side of the thigh bone called the lesser trochanter.

Many maladies can befall the iliopsoas construct.  Sometimes the muscle can be torn away from its origins up in the lumbar spine.

Hip pain from the iliopsoas is typically associated with abnormalities of the tendon between the pelvic rim and the lesser trochanter.  The tendon itself can become inflamed.  This is the so-called tendonitis where “itis” is the Latin word for inflammation.  In addition, the tendon rubs over the front of the hip joint halfway between the pelvis and the lesser trochanter.  Whenever we have two tissues rubbing against each other in the body, we form a small fluid-filled sac called a bursa.  An analogy would be to fill a balloon with tap water and tie off the top.  As you hold the balloon between your two outstretched hands and rub backwards and forwards, the movement is almost frictionless.  That is how a bursa works.  We have eight or nine of these bursae around the hip and about sixteen around the knee.  The bursa between the iliopsoas tendon and the front of the hip capsule is just one of those bursae.  It can also become inflamed.