What is the difference between Tendonosis and Tendonitis

Physio Kent

Treatments for Tendonosis and Tendonitis

Why you probably have TENDON –OSIS and not TENDON –ITIS, and why anti-inflammatories and rest are unlikely to be helping.

Let us look at INFLAMMATION (ITIS) first :

Inflammation is the dynamic process by which living tissue reacts to injury (cell damage).

Cell damage can occur by chemical damage such as acid, infection such as bacteria or viruses, or it can be the body attacking itself like Rheumatoid Arthritis.  For most of us however with “aches and pains”, visiting the doctor or physiotherapist, the cell damage has occurred due to physical trauma.

So following physical trauma – such as a fall or a twist of the knee or ankle, or even getting a splinter, the damaged cells as they tear open release their contents which triggers the classic signs of inflammation – REDNESS, HEAT, SWELLING, PAIN resulting in loss of function.

ITIS refers to disease/damage characterised by an inflammatory process.  Hence, Tonsilitis, Appendicitis, Bursitis (housemaid’s knee) etc.

The released contents of the cell cause redness due to blood vessels opening to increase flow to the area “vaso dilation”.  It is this that causes the increased heat also.  The increased blood flow is also associated with increased vascular permeability allowing protein rich fluid (exudate) to leak into the surrounding damaged area causing “SWELLING”.

The exudate that is released from the ‘leaky’ blood vessels not only causes swelling which offers protection to the area, it also brings with it an army of anti-bodies and other cells which help fight infection, clear up the debris caused by all the cells that were “killed” during the trauma, and helps to repair the damaged blood vessels to stem any bleeding.

Following an acute trauma such as twisting an ankle or knee or falling and causing bruising, the general advice is certainly along the lines of rest, ice, compression, elevation and gently easy mobilisation if comfortable to do so.  The idea is to minimise the inflammatory process which does tend to work on an overkill basis, so calming it down with the addition of anti-inflammatories is quite acceptable under appropriate supervision.

OSIS – is made in reference to a process, usually an abnormal one.  Most tendon strains/injuries will occur due to either overuse, misuse, disuse new use or abuse.  As the term osis suggests unlike inflammation which follow specific immediate and usually memorable trauma, an osis is a process which drip feeds into the tendon, slowly and without being detected.  The tendon usually due to one of the listed reasons above undergoes – “process” of degeneration because for whatever reason, the intracute balance between rate of wear and rate of repair has been upset in favour of wear!

Tendons have a poor blood supply.  They typically have a good enough supply for their own metabolic requirements, and struggle in situations that require increased cell turn over for unexpected repair and maintenance.

Tendons are made up of connective tissue called collage.  Tendons connect muscle to bone and have the ability to withstand high tensile forces.  Tendons are not just inert pieces of rope that tether muscle to bone, they are living tissues in the same way that skin, muscles and bones are.

Tendons are made up of specialist cells called tenoblasts.  These cells are involved in the synthesis making) of collagen.

The vast majority of people who present to the clinic with a tendon related pain or dysfunction can rarely pinpoint an exact time or place that it occurred.  Unlike those individuals who have herniated a disc or pinched a nerve. Those individuals remember the moment it all went horribly wrong very accurately.

The tendon presentation is much more of a gradual non-specific onset, still able to do all activities but simply slowly get more troublesome.  This is due to the gradual “process” that is an –osis but what this means, is that there is not an underlying inflammatory disorder.  This is why a TENDONOSIS will not settle or get better with anti-inflammatories.  The whole R.I.C.E. is unhelpful with an –osis, and whilst if you rest from any aggravating activity you will feel better, and a tendonosis is no different whether it is an Achilles tendonosis, patella or quadriceps; rotator cuff or even plantar fasciitis which is INCORRECTLY labelled –it is.

Whilst the principle of R.I.C.E.  and +/- anti-inflammatories does alleviate the discomfort, it does nothing to strengthen and restore collagen alignment and health and get it back to being able to cope with those high tensile forces.  In fact the prolonged period of rest has potentially further deconditioned the tendon structure so that on return back to sport or increased activity, within a short period of time you are back to square one and back on R.I.C.E. and even longer time off!  When you do return back to activity, the exact same thing will keep re-occurring, tissue “collagen” breakdown, pain and reduced function.  A tendon –osis and tendon –it is are not only very different in their histopathology, but also in their management.  Tendonosis is associated with loss of collagen continuity and increased “ground substance”.  Ground substance is a gel-like substance surrounding the cells, but in chronic overuse tendinopathies (osis) inflammatory cells are absent.