Tendons are a type of fibrous soft tissue that attach muscles to bone and transmit the forces of the muscles to the bone it attaches to. Tendons may also attach to muscle (eyeball muscles) or skin (facial muscles).
Tendons are mainly composed of collagen (same tissue as ligaments and fascia) fibres that are organised into fascicles, groups of fascicles which are mainly made of fibrils, this is where we find the collagen fibrils, tenocytes and others. The importance of this part is that the structure and the way that the collagen fibres are organised at this level are important for the function of the tendons and will vary according to location. Tendons are enclosed by fascia, and the space between the tendons and fascia is filled by paratendon, that serves as a cushion/lubricant. The blood and nerve supply of tendons is much less than what other structures have such as muscles. This is the reason why pain may not be an indication of injury in tendons and also why tendon injuries can be so persistent.
Tendons main functions are:
- Transmit forces from the muscles to the bone, thus moving the bone;
- Absorb external forces and thus prevent injuries.
It is important to know that tendons have a certain characteristic where when they are loaded optimally they become stronger, while when they are loaded inappropriately (this may be over and even underload) they become weaker and may degenerate. Tendons undergo* tensile, compressive, shear and combination loads, depending on which area they are. It is important to know the kind of load a certain tendon undergoes, in order to load it correctly to keep it healthy, prevent injury or treat injuries when they occur.
Types of tendon Injury
Tendinopathy – this is the general term attributed to pathology in the tendons, this may be because the source or exact mechanism of injury is unknown. In some cases this term is used to describe a chronic tendon injury that failed to heal, such as a chronic tendinitis.
Tendinitis – this condition is marked by acute inflammation of the tendon, caused by micro-tears within the fibres.
Tendinosis – is a more chronic condition, where there is degeneration of the fibres due to overuse and there is no inflammation present. The tendon has an increase in immature collagen fibres that are poorly organised and aligned, therefore having less structural integrity and ability to bear loads. These tendons present decreased strength and increased thickness.
Paratenonitis – this is a collective term for the condition where there is inflammation in the paratenon, where the tendon rubs over a bony protuberance.
Injuries to the tendon are generally caused when the tendon is loaded beyond a capacity that it can bear.
- Pain and stiffness at night or in the morning as you get up;
- Localised pain (pain is 1 or 2 fingers wide in the area of pain) and does not disseminate;
- If there is inflammation pain is combined with warmth, redness and/or swelling;
- Tendon may feel crunchy or squeaky upon use;
- Pain is load dependant, that is, it increases with increase in load
- Symptoms are often worse after loading, especially energy storage and release loads, and may be worse the day after the load;
- Decreased strength and flexibility.
Tendon Specific Symptoms:
- Achilles: Stiff in the morning
- Hamstring: Pain in sitting
The main cause for tendon injury is inappropriate load, this may be due to:
- Increase in load in training (too soon, too heavy and/or too fast);
- Change load in training: history of change in shoes, terrain, season in sporting activities;
- Tendon overuse, especially in repetitive activities. These may be occupational such as hammering, typing, sports related such as tennis elbow or recreational, such as repetitive in playing games.
- Repetitive strains;
- Previous tendon injuries that have not healed correctly.
Diagnosis is made through a physical exam, where the history of the pain or injury is recorded and physical tests are performed. Sometimes ultrasound and MRI scans are requested to see the exact location and extent of the injuries. These are helpful to see the integrity of the tendon, whether or not there is thickening, possible dislocations and tears, etc. The tests are also used to check for and clear other possible concurrent injuries. The practitioner will then use all this information to make a diagnosis and guide the treatment accordingly.
Treatment depends on the type of injury, that is why it is important to identify or distinguish the causes of injury as much as possible. In the inflammatory conditions (Tendinitis and Paratenonitis) the aim is to decrease inflammation while in tendinosis there is no inflammation, and the focus is restoring the structure of the tendon and ability to load.
Inflammatory Tendon Injuries
- Protection – this includes relative rest (resting the injured area), using mobility aids or braces to unload the painful/injured structures.
- Optimal Loading – As discussed, tendons need optimal load to function correctly, your therapist should identify the kinds of loads that specific tendon undergoes and devise a program that is focused on correct progressive loading, at the right time.
- Ice – this is an anti-inflammatory measure, decreases the blood flow and slows down the inflammatory process, as well as helping decrease pain.
- Compression – using pressure garments or bandages to wrap the affected area. The pressure applied helps reduce swelling, while allowing movement.
- Elevation – the affected area or limb is elevated above heart level, to decrease the pooling of fluid in the area caused by the inflammatory response and thus decreasing the swelling.
Average timeframe: Days to 6 weeks
Goals for treatment: break the injury cycle, reduce thickening and optimize collagen production and regain tensile strength.
- Movement – movement is encouraged, within the limits of the injury, as it stimulates blood circulation and provides some load to the tissue.
- Exercise – guided progressive load of the tendons, which as stated above, is key to restoring the structure and health of tendons, so they can be able to bear the loads they are subjected to and function well.
- Analgesia – painkillers are helpful in conditions where the pain levels are too high and hinder even simple movements or daily activities.
- Treatment – other modalities that may be beneficial such as soft tissue and trigger point release, scar tissue breakdown, and others (discussed next).
- Ergonomic and biomechanical correction to help alleviate the pain and load on the tendons.
- RICE principles such as Rest, Ice and Compression may be helpful in decreasing pain and load on the tendon and help with the healing process.
- Nutrition – it may be beneficial to supplement one’s diet with substances such as Vitamin C, manganese and zinc that contribute to collagen production, as well as others that may have positive effects on tendon health. Consider consulting a dietician who would be able to better advise and guide on which supplements, and at what doses you should take to better support your healing and recovery.
Early stage treatment average time frame: 6 – 10 weeks
Chronic tendinosis average timeframe: 3 – 6 months average but may last up to 9 months.
It is important to note that some treatment modalities such as anti-inflammatory medication, antibiotics and corticosteroid injections may hinder healing of the tendon, such as hinder collagen repair, especially important in the proliferation and remodelling stage of healing. There have also been studies where these injections were predisposing factors for a tendon tear (strain).
Progressive load of tendons includes different kinds of load:
- Isometric load: a load where there is a muscle contraction without movement. This is used to decrease pain in the tendon.
- Eccentric load: this is when the muscle is contracting while lengthening (or stretching). Eccentric load has been shown to stimulate collagen production and alignment of the collagen fibres, strengthening the tendon.
- Concentric load: this is when the muscle is contracting while shortening, flexing of muscles. This is often combined with eccentric load for overall tendon strengthening.
Physiotherapy treatments are tailored to according to the specific injury, taking into account location, type of injury, stage and severity of the injury. Your physiotherapist will use a combination of different modalities available in order to best treat your condition and get you back to your daily activities and sport. An effective rehabilitation program will also have a preventative component to help you prevent future injuries where possible. A correct diagnosis is vital to healing and prevention of recurrences.