Diagnosis of Posterior heel pain & role of eccentric exercise in mid-portion Achilles tendinopathy

Introduction:

Degenerative disorders of tendons present an enormous clinical challenge. They are extremely common, prone to recur and existing medical and surgical treatments are generally unsatisfactory. Posterior heel pain is a common complaint in both athlete and non-athlete. Posterior heel pain is multifactorial and includes paratenonitis, tendinosis, tendinosis with partial rupture, insertional tendinitis, retrocalcaneal bursitis, and subcutaneous tendo-Achilles bursitis. Each of these entities is distinct, but they often occur in combination.

To avoid stereotyped treatment programs and there by failure of treatment, we need to know & classify homogenous appearing clinical entities into it’s own due place. With respect to posterior heel pain we encounter similar appearing entities in the Achilles tendon itself. Hence Van dijk et al in 2011 has sought clear terminology to delineate each of pain syndromes arising out of posterior heel. Following is an outline of new terminology they proposed; the definitions hereof encompass the anatomic location, symptoms, clinical findings and histopathology.

1. Mid-portion Achilles tendinopathy: a clinical syndrome characterized by a combination of pain, swelling and impaired performance. It includes, but is not limited to, the histopathological diagnosis of tendinosis.

Anatomic location: 2–7 cm from the insertion onto the calcaneus.
Symptoms: A combination of pain, swelling and impaired performance.
Signs: Diffuse or localized swelling
Histopathology: Includes, but is not limited to, the histopathological diagnosis of tendinosis: implies histopathological diagnosis of tendon degeneration without clinical or histological signs of intratendinous inflammation, not necessarily symptomatic

2. Achilles paratendinopathy: Achilles tendon is a weight-bearing tendon that lack a true tendon sheath but ia surrounded by paratenon. There is an acute or chronic inflammation and/or degeneration of the thin membrane around the Achilles tendon in this entity. There are clear distinctions between acute paratendinopathy and chronic paratendinopathy, both in symptoms as in histopathology.

Acute Achilles paratendinopathy:
Anatomic location: Around the mid-portion Achilles tendon
Symptoms: Edema and hyperaemia
Signs: Palpable crepitations, swelling
Histopathology: Edema and hyperaemia of paratenon, with infiltration of inflammatory cells, possibly with production of a fibrinous exudate that fills the space between tendon sheath and tendon

Chronic Achilles paratendinopathy:
Anatomic location: Around the mid-portion Achilles tendon
Symptoms: Exercise induced pain
Signs: Crepitations & swelling less pronounced than it’s acute counterpart
Histopathology: Paratenon thickened as a result of fibrinous exudate, prominent and widespread proliferation of (myo)fibroblasts, formation of new connective tissue and adhesions between tendon, paratenon, and crural fascia

3. Insertional Achilles tendinopathy: located at the insertion of the Achilles tendon onto the calcaneus, bone spurs and calcifications in the tendon proper at the insertion site may exist.

Anatomic location: Insertion of Achilles tendon onto calcaneus, most often with formation of bone spurs and calcifications in tendon proper at insertion site
Symptoms: Pain, stiffness, sometimes a (solid) swelling
Signs: Painful tendon insertion at the mid-portion of the posterior aspect of the calcaneus, swelling may be visible and a bony spur may be palpable
Histopathology: Ossification of enthesial fibrocartilage, and sometimes small tendon tears occurring at tendon-bone junction

4. Retrocalcaneal bursitis: an inflammation of the bursa in the recess between the anterior inferior side of the Achilles tendon and the posterosuperior aspect of the calcaneus (retrocalcaneal recess).

Anatomic location: Bursa in the recess between the anterior inferior side of the Achilles tendon and the posterosuperior aspect of the calcaneus (Retrocalcaneal recess)
Symptoms: Painful swelling superior to calcaneus
Signs: Painful soft tissue swelling, medial and lateral to the Achilles tendon at the level of the posterosuperior calcaneus
Histopathology: Fibro-cartilaginous bursal walls show degeneration and/or calcification, with hypertrophy of the synovial infoldings and accumulation of fluid in the bursa. Alternatively, the bursa may be primarily involved by inflammatory or infectious bursitis due to an inflammatory arthropathy

5. Superficial calcaneal bursitis: inflammation of the bursa located between a calcaneal prominence or the Achilles tendon and the skin.

Anatomic location: Bursa located between calcaneal prominence or the Achilles tendon and the skin
Symptoms: Visible, painful, solid swelling postero-lateral calcaneus (often associated with shoes with rigid posterior portion)
Signs: Visible, painful, solid swelling and discoloration of skin. Most often located at posterolateral calcaneus; sometimes posterior or posteromedial

Histopathology: An acquired adventitious bursa, developing in response to friction. When inflamed, lined by hypertrophic synovial tissue and fluid.

Finally, they suggested that previous terms as Haglund's disease; Haglund's syndrome; Haglund's deformity; pump bump (calcaneus altus; high prow heels; knobbly heels; cucumber heel), are no longer used.

Pathology of Achilles tendon disorders:

Tendinopathy is essentially an 'overuse', degenerative condition. Histopathology studies indicate intratendinous failed healing response and neoangiogenesis in achilles tendinopathy. Neovascularisation evident on Doppler ultrasound correlates well with pain and poor function. Power Doppler study shows microvessels arise on the ventral side of the TA tendon. However according to Richards PJ (2005) there is non-linear relationship between tendonopathy, TA size and the amount of microvascularity.
Mid portion achilles tendionopathy: Tendinopathy of the main body of tendo Achillis affects athletic and sedentary patients. Mechanical loading is thought to be a major causative factor. However, the exact mechanical loading conditions which cause tendinopathy are poorly defined. Repetitive mechanical loading induces a non-inflammatory pathology, and repetitive microtrauma ultimately exceeds the healing response.

Diagnostic clues:

A Haglund's deformity or precisely RCB (Retrocalcaneal bursitis) is present in asymptomatic patients & more to that it does not indicate presence of insertional Achilles tendinitis. A vast majority of the insertional Achilles tendinitis patients have calcification at the tendon insertion (Kang , 2012).

On the basis of X-ray Singh R(2008) for diagnosis of etiology of posterior heel pain described certain angles, lines and soft tissue parameters that focus to describe the calcaneal prominence and its relationship to Achilles tendon and its bursae. Following are the points of diagnosis:
Parallel pitch lines, Chauveaux-Liet angle, ill-defined retrocalcaneal recess, superficial tendo-Achilles bursa and anteroposterior diameter of Achilles tendon more than 9 mm about 2 cm above insertion are reliable objective diagnostic indicators of bony deformity of calcaneus and soft tissue affection in patients with posterior heel pain.

Skeletal US imaging:
A study by Richards PJ (2005) reveal that power doppler is more sensitive to reveal tendon microvascularity than colour doppler in TA tendonopathy. Morphologically abnormal adult TAs were larger than 5.9 mm but power doppler flow is only seen in TAs above 6.5 mm.

Treatment of posterior heel pain:

Although most cases of this disorder are successfully treated nonoperatively, a small subgroup of recalcitrant cases may benefit from surgical intervention. (Impact of conservative treatment is discussed below.)

If paratenonitis is present, the paratenon is partially excised, and adhesions are released. Areas of symptomatic tendinosis are excised with repair of the residual defect in the Achilles tendon. An alternative for patients with tendinosis who are at increased risk for wound problems or who do not want a large open incision is percutaneous or endoscopic tenotomy. A symptomatic Haglund's deformity or inflamed retrocalcaneal bursa is excised. Augmentation of the Achilles tendon may be considered if debridement threatens the structural integrity of the tendon, in older patients, and in revision surgery (6).

Complete ruptures in active, athletic persons should be treated operatively in most cases and result in predictably good outcomes. There may be some cases that escape early recognition and require a reconstructive procedure to salvage a potentially severe functional deficit.

Extracorporeal shock wave therapy, Peritendinous injections and eccentric training decrease neovascularity, relieve pain and improve outcome. Although surgery is the last resort in those patients failing conservative management, it is still unclear how the removal of adhesions and excision of affected tendinopathic areas affects healing and vascularity, or resolves pain.

Other options commonly taken:
US therapy with or without phonophoresis, shoe modification (heel raise) & biomechanical correction through shoe, contrast heat, night splintage in TA stretched position.


Impact of conservative treatment:

According to Richard PJ (2005) in patient with conservatively managed tendinopathy of the mid-Achilles tendon over 1 year there was a reduction of MRI enhancement and number of vessels on power Doppler, followed by morphological improvements and a reduction in size. Vessels per se related to the abnormal morphology and size of the tendon rather than symptoms. Symptoms improve before the Achilles size reduces and the restoration of normal imaging over time.

Role of Eccentric exercise in management of posterior heel pain arising out of achilles tendinopathy:
Recently eccentric, but not concentric, exercises have been shown to be highly effective in managing tendinopathy of the Achilles (and other) tendons. The mechanism for the efficacy of these exercises is unknown although it has been speculated that forces generated during eccentric loading are of a greater magnitude.

All portions of TA suffering achilles tendinopathy do not respond equally to eccentric exercises. Eccentric exercises for the calf muscles have been shown to be effective for chronic non-insertional Achilles tendinopathy (AT). However, the relative effectiveness of various dosages is unknown. Study by Rompe JD et al (2008) found eccentric loading show inferior results to low-energy shock wave therapy in chronic recalcitrant insertional tendinopathy assessed at four months of follow-up. Hence the location of the lesion has a profound effect on efficacy of eccentric exercises.

Dose: Relative effectiveness of various dosages of eccentric exercises for AT is still unclear. However, it appears that highly variable compliance rates result in similar positive outcomes (14).
Possible explanation: According to Rees JD et al; oscillations (while eccentrically loaded) provide a mechanism to explain the therapeutic benefit of eccentric loading in Achilles tendinopathy and parallels recent evidence from bone remodelling, where the frequency of the loading cycles is of more significance than the absolute magnitude of the force.

References:

1. van Dijk CN et al; Knee Surg Sports Traumatol Arthrosc. 2011 May;19(5):835-41. Epub 2011 Jan 11. (Terminology for Achilles tendon related disorders.)
2. Kang S et al; Foot Ankle Int. 2012 Jun;33(6):487-91. (Insertional Achilles tendinitis and Haglund's deformity.)
3. Singh R et al; Foot (Edinb). 2008 Jun;18(2):91-8. Epub 2008 Mar 19. (Diagnostic significance of radiologic measurements in posterior heel pain.)
4. Schepsis AA et al; Am J Sports Med. 2002 Mar-Apr;30(2):287-305. (Achilles tendon disorders in athletes.)
5. Tan SC et al; Disabil Rehabil. 2008;30(20-22):1608-15. doi:10.1080/09638280701792268. (Achilles and patellar tendinopathy: current understanding of pathophysiology and management.)
6. Aronow MS; Clin Podiatr Med Surg. 2005 Jan;22(1):19-43. (Posterior heel pain -retrocalcaneal bursitis, insertional and noninsertional Achilles tendinopathy).
7. Rompe JD et al; Disabil Rehabil. 2008;30(20-22):1666-76. doi: 10.1080/09638280701785825. (Mid-portion Achilles tendinopathy--current options for treatment)
8. McShane JM et al; urr Sports Med Rep. 2007 Oct;6(5):288-92. (Noninsertional Achilles tendinopathy: pathology and management.)
9. Solan M et al; Foot Ankle Clin. 2007 Dec;12(4):597-615, vi. (Management of insertional tendinopathy of the Achilles tendon.)
10. Meyer A et al; Scand J Med Sci Sports. 2009 Oct;19(5):609-15. doi: 10.1111/j.1600-0838.2009.00981.x. Epub 2009 Jul 6. (Eccentric exercise protocols for chronic non-insertional Achilles tendinopathy: how much is enough?)
11. Richards PJ et al; Skeletal Radiol. 2010 Jun;39(6):509-21. doi: 10.1007/s00256-009-0772-0. Epub 2009 Aug 27. (Longitudinal microvascularity in Achilles tendinopathy (power Doppler ultrasound, magnetic resonance imaging time-intensity curves and the Victorian Institute of Sport Assessment-Achilles questionnaire): a pilot study.)
12. Rees JD et al; Br J Sports Med. 2009 Apr;43(4):242-6. doi: 10.1136/bjsm.2008.052910. Epub 2008 Nov 3. (Eccentric exercises; why do they work, what are the problems and how can we improve them?)
13. Rees JD et al; Rheumatology (Oxford). 2008 Oct;47(10):1493-7. doi: 10.1093/rheumatology/ken262. Epub 2008 Jul 22. (The mechanism for efficacy of eccentric loading in Achilles tendon injury; an in vivo study in humans.)
14. Meyer A et al; Scand J Med Sci Sports. 2009 Oct;19(5):609-15. doi: 10.1111/j.1600-0838.2009.00981.x. Epub 2009 Jul 6. (Eccentric exercise protocols for chronic non-insertional Achilles tendinopathy: how much is enough?)