The importance of enthesopathy in Osteoarthritis has only emerged in recent years.
Many people with generalised osteoarthritis often have bouts of isolated clinically enthesopathy such as tennis elbow, plantar fasciitis or trochantertic bursitis.
On X-ray some types of osteoarthritis and especially a condition called diffuse idiopathic skeletal hyperostosis have prominent new bone formation at spinal and other entheses.
The earliest changes in generalised OA that typically initially manifests in the small joints of the hands shows prominent enthesopathy on high resolution magnetic resonance imaging scanning.
In other joints including knee osteoarthritis where a quarter of cases had changes at the anterior cruciate ligament insertion. The importance of disease in the ligament and enthesis awaits further study.
These and other emerging facts lead to a new classification of Osteoarthritis that proposes and important subgroup of common disease that starts at the enthesis.
Some animal models strong support the primacy of the enthesis and adjacent ligaments in the development of Osteoarthritis
In Osteoarthritis abnormalities at the insertion may have a "knock on" effect and contribute to bone erosion adjacent to the insertion.
Since insertions are ubiquitous throughout the skeleton pain coming from them is probably very common in Osteoarthritis but difficult or clinically impossible to define at some sites.
The commonly recognised sites of enthesopathy in Osteoarthitis include
However, physicians may not appreciate or recognise enthesopathy at other sites including the
It is vital to realise that the insertions are sites of stress, microdamage and wear and tear. This is a normal phenemonon!
However, with age it appears that repair functions sub-optimally. The immune system plays a role in this normal turnover and repair. In Osteoarthritis the initial phases of repair may be associated with inflammation to clear away damaged tissue. Therefore this type of pain may not be bad and may settle.
For the enthesopathy associated with osteoarthritis the following approach can be used.
Where possible eliminate heavy activity e.g. lifting and elbow disease
Weight reduction for lower limb enthesopathy
Physiotherapy including stretching exercises
Podiatry for foot malalignment or soft heel raise for plantar fasciitis.
Simple analgesia taken only when pain is especially bothersome pain
Non-steroidal anti-inflammatory drugs where not contra-indicated
Local enthesis corticosteroid injection
If no response this can be repeated. Some physicians do an ultrasound guided injection in hope that accurate needle placement helps
"Autologous blood patch" - A sample of the patients' blood taken and injected into painful enthesis.
Platelet rich plasma or PRP- contains growth factors but no blood as above. This is fashionable but not proven.
Extra corporeal shock wave lithotripsy (ESWL). This technique breaks up kidney stones. One basis that abnormal calcium and bone formation occurs in some painful enthuses an attempt is made to dissolve these in belief that it will relieve pain. Controversial area and more studies needed.
Radiotherapy - occasionally used for enthesitis in other diseases but not in Osteoarthritis.
For tennis elbow the insertion of the involved muscle can be cut or released.
As the muscle is attached over a wide area of adjacent bone this has no major implications.
For resistant plantar fasciitis cutting the insertion could disrupt the foot arch.
Treatment of Generalised Entheseal Disease in Osteoarthritis - at this time no effective therapy.