It is important to distinguish between midportion and insertional Achilles tendinopathy as they differ in their prognosis and response to treatment. We briefly review the pathology of Achilles tendinopathy, list expert opinion of the factors that predispose to injury, and summarize the clinical features of the condition. The subsequent section details the treatment of midportion tendinopathy.
Histopathology and Basic Molecular Biology
When operating on patients with chronic Achilles tendinopathy, the surgeon generally finds a degenerative lesion characterized by an intratendinous, poorly demarcated, dull-grayish discoloration of the tissue with a focal loss of normal fiber structure. The paratendinous structures are either normal or contain edema or scarring. Importantly, when the symptomatic parts of such Achilles tendon tissue are examined under the light microscope, there is collagen fiber disarray. This applies equally to areas of partial tear, which show hypervascularity without signs of tissue repair. This histopathological picture is called 'tendinosis' and is identical in tendons with macroscopically evident partial tears and those without.
Risk Factors of Achilles Tendinopathy
Injury to the Achilles tendon occurs when the load applied to the tendon, either in a single episode or, more often, over a period of time, exceeds the ability of the tendon to withstand that load. Factors that may predispose to Achilles tendinopathy include:
- Years of running
- Increase in activity (distance, speed, gradient)
- Decrease in recovery time between training sessions
- Change of surface
- Change of footwear (e.g. lower heeled spike, shoe with heel tab)
- Excessive pronation (increased load on
- Gastrocnemius-soleus complex to resupinate the foot for toe-off)
- Calf weakness
- Poor muscle flexibility (e.g. tight gastrocnemius)
- Joint range of motion (restricted dorsiflexion)
- Poor footwear (e.g. inadequate heel counter, increased lateral flaring, decreased forefoot flexibility)
- Genetic predisposition
Practise Tips Relating to Imaging Achilles Tendinopathy
There are various appearances of Achilles tendinopathy with imaging. Thus, we recommend that the history and physical examination remain the keys to diagnosis. Until patients become familiar with the concept of tendinosis, imaging may help illustrate that the abnormality is one of collagen disarray and abnormal vasculature; this will help the patient understand the lengthy time course of healing.
Treatment of Midportion Achilles Tendinopathy
- Level2 evidence-based treatments for Achilles tendinopathy include heel-drop exercises, nitric oxide donor therapy (glyceryl trinitrate [GTN] patches), sclerosing injections and microcurrent therapy (see below).
- In addition, experienced clinicians begin conservative treatment by identifying and correcting possible etiological factors.
- This may include relative rest, orthotic treatment (heel lift, change of shoes, corrections of malalignment) and stretching of tight muscles.
- Whether these 'commonsense' interventions contribute to outcome is unlikely to be tested.
- The sequence of management options may need to vary in special cases such as the elite athlete, the person with acute tendon pain unable to fully bear weight, or the elderly patient who may be unable to complete the heel-drops.
1. Adjunct Conservative Treatments
- Biomechanical evaluation of the foot and leg is a clinically important part of Achilles tendon management.
- Although there is little empirical evidence to support the association between static foot posture and Achilles tendinopathy, modification of foot posture in some patients can reduce pain and increase the capacity to load the tendon.
- Similarly, soft tissue therapy of the calf complex can assist rehabilitation, as can tendon mobilization.
- Frictions have been shown to increase the protein output of tendon cells; however, similar to the effect seen with ultrasound, greater amounts of collagen and ground substance may not improve pain or pathology.
2. Surgical Treatment
- Surgical treatment procedures range from simple percutaneous tenotomy to removal of tendon pathology via an open procedure. Percutaneous tenotomy resulted in 75% of patients reporting good or excellent results after 18 months.
- The outcome of open surgery for Achilles tendinopathy was superior among patients whose tendons had diffuse disease compared with those whose tendons had a focal area of tendinopathy. At seven months post-surgery, 88% of those with diffuse disease had returned to physical activity, as had 50% of those with a focal lesion.
- All Achilles tendon surgery requires early post-operative rehabilitation and this needs to continue for six to 12 months as final clinical results rely on the return of strength and functional capacity.
- Wise patients will continue with a maintenance program of physiotherapist-prescribed rehabilitation exercises even after having returned to training and competition.
