Kamis, 22 November 2007

Achilles Tendonitis


Background

The Achilles tendon, named after the seemingly indestructible mythologic Greek warrior, is the largest and strongest tendon in the human body. Achilles tendonitis was the term originally used to describe the spectrum of tendon injuries, ranging from inflammation to tendon rupture. Recently, a histopathologically determined nomenclature has evolved to classify this range of tendon inflammation and degeneration into 3 stages: (1) peritenonitis, (2) peritenonitis with tendinosis, and (3) tendinosis.



Partial or full tendon ruptures may result from end-stage peritenonitis. Causes of tendon ruptures are associated with overuse and host susceptibility with both extrinsic and intrinsic factors playing a role. Athletes who are poorly conditioned, overtrained, or insufficiently prepared are at the highest risk for this disease process. Repetitive stresses to the tendon, such as prolonged jumping or running, result in chronic pain and tightness along the tendon. Tendonitis usually develops insidiously after sudden changes in activity or training level, use of inappropriate footwear, or training on poor running surfaces, especially if high risk factors are present (eg, age, cavus feet, tibia vara, heel and forefoot varus deformities).

Frequency

United States

True incidence of Achilles tendonitis is unknown, although there is a reported incidence of 6.5-18% in runners.

Functional Anatomy

The Achilles tendon (tendo calcaneus) is formed from the tendinous contributions of the gastrocnemius and soleus muscles, coalescing approximately 15 cm proximal to its insertion. Along its course in the posterior aspect of the leg, the tendon spirals 30-150° until inserting into the calcaneal tuberosity. The tendon's ability to glide is facilitated by the presence of a thin paratenon sheath, which is composed of both a visceral layer and parietal layer, rather than simply a true synovial sheath. The tendon's blood supply arises from the osseous insertion, the musculotendinous junction, and multiple infiltrating mesotenon vessels, which cross the layers of the anterior paratenon.

Various injection and nuclear medicine studies have demonstrated a paucity of mesotenon and intratendinous vessels 2-6 cm proximal to the heel insertion known as the watershed area. Due to the relative lack of blood supply in the watershed area, this area of the tendon is less resilient to repetitive microtrauma and has a higher tendency for irritation, degeneration, and possible rupture.

Sport Specific Biomechanics

The entire gastrocnemius/soleus musculotendinous unit spans the knee joint, tibiotalar (ankle) joint, and talocalcaneal (subtalar) joint. Contracture of this complex flexes the knee, plantar flexes the ankle, and supinates the subtalar joint. During running, forces equaling 10 times the body weight have been measured within the tendon.

Treatment

Acute Phase

Rehabilitation Program

Physical Therapy

Peritenonitis

Recommend rest and limitation of activities determined by the severity and duration of pain. Ice compresses can be used for relief of acute pain and inflammation following activities. Recommend nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation. Suggest a heel lift of 1-2 cm on a temporary basis for comfort. Heel lifts on a prolonged basis may result in tendon shortening.

Instruct the patient in stretching, training modification/re-evaluation, and muscle strengthening. Stretching exercises are believed to be the key modality in treatment as they provide better flexibility to the ankle. Stretching of the posterior gastroc-soleus complex should always be slow and deliberate. Each stretch should last for 20-30 seconds, with multiple repetitions in a set.

Three possible methods of stretching the gastroc-soleus complex include 1) incline board, 2) wall leans, and 3) "foot on chair" stretching. An incline board is a fabricated ramp of 15-18° that allows the patient to gradually stretch the heel cord complex. A much simpler method is to have the patient stand and face a wall, while leaning with his knees extended and his heels planted on the ground. The "foot on chair" method requires the athlete to place his foot flat on a chair, and gradually bring his knee forward as far as possible without losing heel contact with the chair. Use orthotics to treat overpronation or heel cups to provide extra support and cushion to the tendon. Return to activities is gradual.

Tendinosis

Tendinosis alone usually is asymptomatic and is noticeable only with palpation of a nodule or fullness along the tendon. Tendinosis becomes symptomatic when coexistent peritenonitis is present and the patient complains of activity-related pain or swelling. Treatment is first conservative with methods similar to simple peritenonitis. Six to eight weeks of activity modification, orthotics (walking boot with a heel lift), anti-inflammatory analgesics, and physical therapy should be prescribed prior to any operative treatment or orthopedic referral.

Certain modalities have been used in physical therapy programs. Therapeutic ultrasound provides silent mechanical vibrations of high frequency that penetrate superficial tissue in order to generate deep heat. Ultrasound has been shown in some studies to increase the rate of collagen synthesis and the breaking strength of the tendon. Ultrasound's effectiveness as an anti-inflammatory technique remains unproven. Both phonophoresis and iontophoresis deliver topically applied anti-inflammatory medications transdermally with the aid of mechanical ultrasound energy or an electrical field gradient, respectively. Typically, because the anti-inflammatory substance is a steroid (known to weaken tendinous tissue), we do not recommend its use.

Medical Issues/Complications

Steroid injections into and around the tendon are not advised because they have been shown to weaken the tendon.

Surgical Intervention

Operative treatment is indicated in athletes with peritonitis and/or tendinosis after a comprehensive conservative treatment program has failed and who are unwilling to modify or stop their activity. Although there are no absolute indications, relative contraindications include noncompliant patients, active infection site, and patients with potential wound healing problems (eg, diabetes mellitus, peripheral vascular disease, smokers).

Lysis of adhesions through release of the Achilles tendon from the inflamed paratenon is the mainstay procedure for unrelieved peritonitis. Release is performed on the dorsal, medial, and lateral aspects of the tendon. Circumferential dissection to include the anterior sheath may jeopardize the vascular supply to the tendon and cause excessive scarring. This surgery is followed immediately with passive range of motion (PROM) and progressive weight bearing and strengthening for 2-3 weeks. When ambulating without pain, the patient may begin closed chain activities, such as biking or stair climbing. Running may begin at 6-10 weeks after surgery. Participation in competitive sports can start after 3-6 months.

For people with tendinosis, failure of nonoperative treatment often requires excision or splitting of the paratenon, debridement, and repair of the degenerated tendon with side-to-side repair. Following the operation, a period of protected weight bearing, ROM, and strengthening is advised until return to full activities is achieved.

Other Treatment

Operative brisement (ie, injection of dilute anesthetic into the paratenon sheath under ultrasound guidance to break up adhesions) may be useful in patients with peritenonitis or tendinosis with peritenonitis.

Recovery Phase

Rehabilitation Program

Physical Therapy

See Physical Therapy above.

Medical Issues/Complications

Tendonitis may go onto rupture. Steroid injections, especially multiple injections, may weaken the tendon leading to tendon rupture.

Maintenance Phase

Rehabilitation Program

Physical Therapy

Achilles tendonitis is best prevented, treated, and maintained by preserving good ROM in the heel cord complex. Such motion can be gained with the use of an incline board, wall leans, or the "foot on chair" stretching exercises as described. Moist heat or compresses prior to workouts and at night are beneficial. Cold modalities should be used following strenuous activities to provide pain relief and anti-inflammatory effects.

Medication

No medical therapy of choice exists. Most patients are treated symptomatically with acetaminophen or NSAIDs as determined by the patient's medical condition and physician's preferences.

Drug Category: Analgesics/antipyretics

Pain control is essential to quality patient care. Analgesics ensure patient comfort and have sedating properties, which are beneficial for patients who have sustained trauma or have sustained injuries.

Drug NameAcetaminophen (Tylenol, Feverall, Tempra)
DescriptionDOC for pain in patients with documented hypersensitivity to aspirin or NSAIDs, with upper GI disease, or who are taking oral anticoagulants.
Adult Dose650 mg PO q4h prn
Pediatric Dose10-15 mg/kg PO q4h prn
ContraindicationsDocumented hypersensitivity
InteractionsRifampin can reduce analgesic effects of acetaminophen; coadministration with barbiturates, carbamazepine, hydantoins, and isoniazid may increase hepatotoxicity
PregnancyB - Usually safe but benefits must outweigh the risks.
PrecautionsHepatotoxicity possible in patients with chronic alcoholism following various dose levels; severe or recurrent pain or high or continued fever may indicate a serious illness; APAP is contained in many OTC products and combined use with these products may result in cumulative APAP doses exceeding recommended maximum dose

Drug Category: Nonsteroidal anti-inflammatory drugs (NSAIDs)

Have analgesic, anti-inflammatory, and antipyretic activities. Their mechanism of action is not known, but may inhibit cyclo-oxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell membrane functions.

Drug NameIbuprofen (Motrin, Advil)
DescriptionDOC for patients with mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.
Adult Dose200-600 mg PO q8h prn
Pediatric Dose10 mg/kg PO q6-8h prn
ContraindicationsDocumented hypersensitivity; peptic ulcer disease, recent GI bleeding or perforation, renal insufficiency, or high risk of bleeding
InteractionsCoadministration with aspirin increases risk of inducing serious NSAID-related side effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; monitor PT closely (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently
PregnancyD - Unsafe in pregnancy
PrecautionsCategory D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy