When a tendon is subjected to an often prolonged strain that exceeds the strength of the tendon, acute ‘inflammation’ of the tendon can occur. In some cases, only a very short-term overload (e.g. one blow) is required. The inflammation contributes to healing and subsides once the tendon has normalised.
In the past, tendonitis was thought to be caused by wear and tear (degeneration) of the tendon and the condition was called tendinosis. Others believed that it was purely a strain-induced inflammation and the condition was therefore called tendinitis. Today, tendonitis is called tendinopathy, which ignores whether it is primarily caused by degeneration or inflammation. However, it is a fact that completely healthy tendons exposed to one relevant trauma can develop severe tendinitis, even though there are most likely no wear and tear (degenerative) changes in the tendon.
If the overload continues, the acute inflammation can turn into chronic inflammation, which is a serious complication. Chronic inflammation causes the tendon to become persistently painful and thicker, but at the same time weaker as the chronic inflammation breaks down the tendon tissue. There is therefore a significantly increased risk of rupture if the overload continues. The pain necessitates a reduced load with the risk of further weakening of muscles, tendons, ligaments and bones if specific rehabilitation to strengthen the tendon (and all other muscles) is not started at the same time.
Muscle injuries often take weeks or months to heal, while tendon injuries often take six months to a year to heal. Chronic tendonitis is therefore one of the longest-lasting and most difficult sports injuries to treat, and in the worst case scenario can make it impossible to return to sport (‘sports disability’).
It is therefore crucial for continued sporting activity to prevent chronic inflammation by reacting as quickly as possible to soreness and pain in the tendon, signalling that ‘something is wrong’. It is therefore highly inadvisable to ‘bite the bullet’.
It is therefore crucial for continued sporting activity to prevent chronic inflammation by reacting as quickly as possible to soreness and pain in the tendon, signalling that ‘something is wrong’. It is therefore highly inadvisable to ‘bite the bullet’.
The overload causes changes in the tendon tissue that initially do not cause symptoms, but can often be seen on ultrasound scans. The soreness and pain usually only occur when the tendon changes are quite pronounced.
Tendon injuries are therefore often compared to an iceberg (the iceberg theory – Fredberg U, Stengaard-Pedersen K. 2008), where only the 10% above the pain threshold (‘above sea level’) can be registered, while the remaining 90% of the injury is symptom-free (below the pain threshold/‘below sea level’).
Therefore, when you become pain-free due to reduced load, you still have 90% of the injury, which requires continued slowly increasing rehabilitation within the pain threshold, often for several months before the tendon is strong enough for full load, even though the pain has subsided. During this period, there is a significant risk of relapse if rehabilitation is rushed.
Adrenal cortex hormone has proven effective in relieving the pain of tendinopathy, but the injections cannot correct training errors (overload) or make tendons stronger – only proper training can do that. Adrenal cortex hormone should therefore always be combined with a reduction from pain-triggering activity and a slowly increasing rehabilitation over several months within the pain threshold to reduce the risk of relapse and tendon ruptures.
Studies have shown that if adrenal cortical hormone injection is not combined with unloading and slow rehabilitation, the effect will only be short-term, but if the injection is combined with proper rehabilitation, there are both short-term and long-term effects compared to rehabilitation alone (Johannsen FE, et al. 2019).
In recent years, there have been various experimental injection treatments such as sclerosing injection therapy (injecting an agent around the tendons to destroy the small vessels (and nerves) that grow into the diseased tendons) and platelet-rich plasma therapy (injecting your own platelets containing a high concentration of growth hormone). There is no clear evidence of the efficacy of these treatments. High Volume treatment involves injecting a small amount of adrenal cortical hormone dissolved in large amounts of local anaesthetic and saline, but the effect is not significantly different from treatment with adrenal cortical hormone alone (Johannsen FE, et al. 2019).
