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!
In addition to pain, patients with hip arthritis also note restrictions in range of motion of the joint. Typically, the joint loses the ability to abduct (go out to the side), internally rotate (turn the foot inwards), and fully extend or straighten backwards.
These features combine to limit how far the patient can walk, give rise to difficulties doing up shoes and putting on socks, and give rise to difficulties climbing in or out of a car, ascending or descending steps and engaging in sexual intercourse.
The diagnosis of hip arthritis is made from the clinical symptoms provided by the patient, the features noted at the time of clinical examination (restrictions in movement and pain with specific provocative manoeuvres) and x-ray or radiographic features. Sometimes blood tests can be of assistance, as can more complex scans such as computerised tomographic (CT) scans or MRI (magnetic resonance image) scans.
With all conditions orthopaedic, the treatment programmes can be divided into two groups. The first is the so-called non-operative approach.
This includes pain relief, weight loss, the ingestion of anti-inflammatory analgesic agents, the use of a walking stick, crutches, wheelchair or moped or injections of cortisone or other lubricants into the joint.
The second arm is of an operative nature. There are many operations available. They can include telescopic procedures, laser procedures and even transplantation procedures. Joint replacement, at the end of the surgical line, is often the only option left when patients present with advanced hip arthritis.
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.
The orthopaedic surgeon is able to make the diagnosis often on the basis of the history and on the clinical features noted at the time of examination. X-rays are also very useful. We see what we call a “bump” appearing at the junction between the upper end of the thigh bone (the ball) and the neck to which the ball is attached. Ask your orthopaedic surgeon to point this feature out if you do suffer with FAI. MRI scans are also very useful. Not only can the impingement site be localised, but damage to the other structures within and around the joint can also be identified. Typically, the socket or the acetabulum has a soft flange-like structure surrounding it called the labrum. This labrum can become detached. It can give rise to pain, clicking, clunking and locking. In addition, the very specialised cartilage, or white smooth glistening material that lines the socket, can become damaged. Mechanical attrition can result in the cartilage peeling away. A chemical inflammatory process can also be incited. The cartilage cells (chondrocytes) do not normally have a blood supply. They get their nutrition by fluid being squeezed in and out with joint movement. When the cartilage cells are exposed to the host immune system, and autoimmune reaction can be created. This is how the arthritis from FAI can become quite rapid and severe.
As with all things orthopaedic, the management can be either non-operative or operative. Non-operative measures are simply directed to curtailing the symptoms. This will include weight loss, avoiding the provocative activities and ingesting analgesics or anti-inflammatory agents.
From an operative perspective, if it is caught early enough, the FAI symptoms can be dramatically reduced by arthroscopic or telescopic surgery. The bump can be removed from the femoral neck, the labrum can be re-attached to the edge of the socket, and any spurs that have formed can also be removed.
While this type of arthroscopic surgery may theoretically retard or even prevent the subsequent appearance of osteoarthritis of the hip joint, the research so far is inconclusive. It is to be hoped that longitudinal studies that are currently being performed will provide some evidence (one way or the other) over the next few years. This is a space to be watched.
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.
Labral tears are not uncommon and typically appear more frequently with age. They form part of the age-related degenerative spectrum. Not all labral tears are symptomatic. They can sometimes be incidental findings on MRI scans.
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.
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.
Abductor dysfunction can present in a number of manners.
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.
Not all forms of abductor dysfunction are associated with pain but they do often give rise to ambulatory incapacity. Their diagnosis requires the gleaning of a thorough history, the performing of a complete examination and ancillary investigations including plane radiographs and an MRI scan.
Treatment modalities can be of a non-operative nature and include physiotherapy and muscle exercises in the gym environment, the local installation of hydrocortisone and local anaesthetic, or even the use of splints or supporting devices.
Operative options can include repair of ruptured tendons, the excision of an inflamed bursa, or even reconstruction of the mechanism using artificial material such as meshes and tapes.
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.
Patients with iliopsoas tendonitis or iliopsoas bursopathy usually complain of groin pain. It is made worse by flexing the hip, especially against resistance. Attempting to get into or out of a car is often painful. Other activities which may provoke pain with hip arthritis are usually not so uncomfortable with iliopsoas tendinopathy.
The diagnosis requires the taking of a careful history, the performance of a thorough physical examination, and sometimes ancillary investigation with an ultrasound scan or an MRI scan.
Treatment options can be of a non-operative or operative nature. Those of a non-operative nature usually include rest, the avoidance of provocative activities and sometimes the ultrasound-guided administration of hydrocortisone preparations.
From an operative perspective, a release of the tendon can often be very successful. This is not infrequently performed during the course of a hip replacement and sometimes it is also required following hip replacement surgery.