Modern evidence has shown that there is seldom a need to repair a ruptured Achilles tendon with surgery. Treatment without an operation brings excellent results. Understanding the natural healing processes involved will help you to follow the advice and precautions that are necessary to ensure a great outcome from your injury.

The human body has incredible capacity for repair. Injuries to tendons, ligaments, skin and bones follow broadly similar phases of healing. Although modern medicine is helpful in some specific situations, intervention (especially surgery) must be carefully weighed up. Are there really benefits from surgical repair? If so, do these benefits outweigh the risks of the surgery?

Natural Healing

Skin

Injuries to skin, ligament, tendon or bone all cause bleeding. This is obvious when the skin is involved. For other tissues the bleeding is hidden beneath the skin, resulting in bruising and swelling.

We are all used to seeing how skin heals. The bleeding stops; a scab forms; the skin re-grows beneath the scab; the scab falls away leaving a scar. If a cut is sewn up with stitches, then the skin edges are close together. This may reduce the risk of an infection. However, if the wound is left open it still heals.

Bone

Broken bones (fractures) bleed too, and the “scab” that forms around the bone ends is called callus. Initially this is soft (and flexible) so a splint, cast or sling help to keep the broken bone still and more comfortable. The callus becomes gradually stiffer, as calcium builds up within it, slowly forming new bone. This is like glue or cement setting. When the new bone stiffens, the injury stops hurting. The thick “blob” of new bone slowly reduces in size. Eventually it is impossible to see on an x-ray that there was ever any damage at all.

Tendon

A tendon is tough gristle that connects a muscle to the bone. This allows the muscle to move the bone when it flexes. The tendon is like a puppet string. The Achilles tendon (the largest in the body) joins your calf muscle to the heel bone. When your calf muscle contracts you rise onto tiptoes.

Figure 1. A tendon connects a muscle to a bone.

Tendons are made of fibres (collagen) bound together in small bundles that in turn are bunched together to form the “rope”. If you think of a horse’s tail wrapped in clingfilm then you are pretty close. In between the bundles there are blood vessels as well as other connective tissue to keep the tendon healthy and lubricated.

Figure 2. Structure of the tendon is like a horse’s tail wrapped in cling-film.

When the tendon tears there is bleeding. This blood is contained within the clingfilm (called paratenon) that surrounds the tendon. A blood clot forms around the two ends of the torn tendon (haemostasis). The tendon ends are both very ragged, since the fibres all tear at a different point, giving the appearance of two mop-ends. Inflammation in the area, during the first week, encourages healing cells (fibroblasts and macrophages) to begin their work. As healing progresses, the blood clot becomes stiffer like glue setting. New collagen fibres form and hold the tendon together (proliferation). Initially, the fibres are made of different collagen and are not neatly arranged in bundles. This dis-organised collagen is not as strong as normal tendon and takes about 6 weeks to form. Gradually the healing tendon matures (remodelling). Only then, after 18-24 months, does it reach its maximum strength.

Figure 3: Tendon healing phases

Haemostasis

Inflammation

Consolidation

Remodelling

After Healing

After a few weeks the tendon is healed, but the “glue is still soft”. There is a risk that the tendon will stretches or re-rupture. These risks become smaller with the passage of time. Re-rupture is rare after 6 months.

Once the tendon is fully healed it is tough and strong but contains some permanent scar tissue. In this respect it is more like skin (where a visible scar always remains) than bone (where the healing is nearly perfect).

Implications for your recovery

To ensure a good recovery from your Achilles tendon rupture three conditions must be met:

1. The two ends of the tendon must be securely joined together
2. The length of the tendon must be the same as it was before injury
3. The muscle power must be restored with exercises

Obviously if the tendon does not join (or re-ruptures) then the muscle is not connected to the bone and so (in the case of the Achilles tendon) you lose the ability to stand on tip toes with any strength. You may have a little movement still, because the toe tendons can compensate a little.

If the tendon heals but is stretched and elongated, then the “puppet string” is long and baggy and however hard the muscle tries to pull it cannot lift the heel properly. This is why it is so important that you do not cut any corners when recovering. The foot must remain in a tip-toe position at all times – day and night. One mistake pulls the healing ends apart.

Once strong enough to give up the boot, muscle building exercises begin. These exercises are designed to improve muscle strength without overstretching the tendon. It is important to follow the protocol carefully. Overzealous activity can lead to stretching of the tendon or re-rupture.

Stretching exercises are discouraged for up to a year for fear of the newly healed tendon stretching. Even if your Achilles feels too tight, which is common after weeks in the high-heeled boot, be patient and allow it to gradually adapt with normal use. Engaging in aggressive stretching may cause elongation and loss of power in the ankle. Once the tendon is over-stretched it will not tighten up again.