Description

• Spectrum of disorders involving Achilles tendon, paratenon, and retrocalcaneal bursa
• Painful inflammation of Achilles tendon and its sheath due to chronic degenerative tendinosis and tearing
• Anatomy
  • Tendon is largest and strongest in body, peak loads 6 to 8 times body weight during running.
  • Formed from tendinous contributions of gastrocnemius and soleus muscles
  • Assists in knee flexion, foot plantar flexion, and hindfoot inversion
  • ~15 cm long, inserts on posterior calcaneal tuberosity
  • Surrounded by paratenon
• Definitions
  • Retrocalcaneal bursitis: inflammation of retrocalcaneal bursa, posterior heel pain
  • Paratenonitis: paratenon inflammation associated with warmth, swelling, diffuse tenderness
  • Paratenonitis with tendinosis: diffuse swelling of tendon sheath, nodularity of tendon
  • Tendinosis: intrasubstance degeneration of tendon, typically 2 to 3 cm proximal to insertion
  • Insertional enthesopathy: pain at the insertion of the Achilles tendon onto the calcaneus
  • Tendon rupture: tear in substance of Achilles tendon, usually watershed region
• Tendinopathy locations
  • Midportion (2 to 3 cm proximal to calcaneal insertion): ~55–65% of injuries
  • Insertional: retrocalcaneal bursitis: ~20–25% of injuries

Epidemiology

• Tendinopathy
  • Recreational and competitive athletes
  • Common in active middle-aged individuals
  • Degenerative tendinosis seen in middle-aged to elderly, regardless of sports participation
• Rupture
  • Male-to-female ratio: 1.7:1 to 12:1
  • Left-side injury > right-side injury
  • More common in industrialized countries
  • Healthy men aged 30 to 50 years without previous injury
  • Often no prodromal Achilles pain
  • “Weekend warriors”—minimal weekday activity

Incidence

• Achilles disorders affect ~1 million athletes per year.
• Tendinopathy true incidence unknown
  • Runners, 6.5–18%; dancers, 9%; gymnasts, 5%; tennis, 2%; football, <1%
  • 10 times increase in runners versus age-matched controls
• Rupture
  • Unclear, varies 2 to 37.3 per 100,000
  • Increasing incidence in recent decades with increasing number recreational athletes

Etiology and Pathophysiology

• Achilles tendon blood supply
  • Intrinsic: posterior tibial artery
  • Extrinsic: mesosternal vessels crossing paratenon
  • Watershed zone 2 to 6 cm from posterior calcaneal insertion
  • Supply decreased with age causing degeneration of watershed region.
• Histopathology shows evidence of degenerative changes and chronic tendinosis.
• Disorganized collagen structure, fibrinous exudates, adhesions, increased growth of neurovascular bundles in the paratenon
• Tendinopathy
  • Overuse causing microtrauma and mechanical breakdown of tendon
  • Extrinsic causes: overuse, stairs, hill climbing, improper shoes/training surfaces/stretching, corticosteroid use
  • Intrinsic causes: tight Achilles, varus heel/foot, cavus foot, leg length discrepancy, diabetes
• Rupture
  • Most common: sudden forced plantar flexion, unexpected dorsiflexion, or violent dorsiflexion of a plantar flexed foot
  • Less common: direct trauma

Genetics

• Specific variations of genetic sequence increase susceptibility of injury.
• Environmental factors altering gene expression

Risk Factors

• Tendinopathy/bursitis
  • Haglund process—large posterosuperior calcaneal tuberosity
  • Diabetes, lupus, rheumatoid disease, obesity
  • Hemodialysis or peritoneal dialysis
  • Connective tissue disease
  • Stop and go sports, male gender
• Rupture
  • Medications: corticosteroids, anabolic steroids, fluoroquinolone antibiotics
  • Recreational athletes—abrupt changes in activity level/training/intensity
  • Poorly conditioned, advanced age, overexertion
  • Previous injury or rupture

General Prevention

• Conditioning, stretching, warm-up: thought to produce tendon adaptation and increase cross-sectional area
• Avoid rapid increase in running mileage, training intensity, excessive hill running.

History

• Tendinopathy
  • Pain, swelling, warmth along tendon
  • Noninsertional most common
  • Pain exacerbated by activity, relief with rest
• Peritonitis—localized burning pain accompanies/follows activities
• Rupture
  • Sudden “snap” or “pop,” severe pain, calf swelling, loss of plantar flexion power

Physical Exam

• Retrocalcaneal bursa: swelling, warmth, bogginess anterior to tendon
• Tendinopathy
  • Localized pain—insertional versus noninsertional
  • Swelling of tendon sheath, nodular swelling, or crepitus with motion
  • Evaluate for pes cavus, leg length, scoliosis, and equinus deformity.
• Rupture
  • Pain, swelling, ecchymosis, palpable gap
  • Weak active plantar flexion
  • Knee flexion test (Matles test): prone position, knees flexed to 90 degrees; affected side may reveal excessive dorsiflexion.
  • Thompson test: prone position, leg extended with ankles off edge of table. Squeeze calf with no passive plantar flexion of affected foot.
  • If Thompson test equivocal
  • O’Brien needle test: Insert 25-gauge needle 10 cm proximal to calcaneus along midline of calf. Passive dorsiflexion/plantar flexion reveals movement of needle in opposite direction if tendon intact (needle is still with rupture).
  • Copeland sphygmomanometer test: patient prone with knee flexed to 90 degrees. Inflate BP cuff to 100 mm Hg with ankle plantar flexed. When ankle dorsiflexed, pressure should increase to ~140 mm Hg if tendon intact; no change if rupture

Differential Diagnosis

• Precalcaneal bursitis, peroneal/posterior tibialis tendinitis/rupture
• Inflammatory arthritis
• Ankle fracture or sprain
• Calcaneofibular or talofibular injury
• Calcaneal apophysitis (Sever disease)

Diagnostic Tests & Interpretation

Initial Tests (lab, imaging)

• History and physical examinations yield accurate diagnosis in 90% of cases.
• Labs—only if suspect systemic illness
• Imaging
  • Plain films (anteroposterior [AP]/lateral/oblique) for bony structure and rule out other injuries
  • Ultrasound for tendon thickness, tear
  • Magnetic resonance imaging (MRI) to distinguish paratenonitis, tendinosis, bursitis, incomplete ruptures, degeneration

General Measures

• Tendinopathy
  • Ice, nonsteroidal anti-inflammatory drugs (NSAIDs), rest (LOE: C)
  • Heel lift, orthotics, appropriate footwear (LOE: C)
  • Eccentric exercises/Alfredson protocol for midportion tendinitis (LOE: A)
  • Avoid eccentric exercises, uphill walking in insertional tendinitis (LOE: C).
  • Correct training errors, stretching (LOE: C).
  • Retrocalcaneal bursa: Consider injection for symptom and inflammation relief.
  • If unresponsive—trial of immobilization
  • Noninsertional—conservative treatment
  • Insertional—treat coexisting pathologies
  • Consider surgical referral after 6 months.
• Rupture
  • Immediate, below the knee non–weight-bearing (NWB) splint in equinus position
  • Rest, pain control, ice, elevation
  • Conservative management versus surgical repair (open vs. percutaneous)
    • Case-by-case decision accounting for patient age, general health/comorbidities, activity level, and individual preference
  • Conservative management
    • Conservative treatment using functional rehab/early range of motion with similar rerupture rates of surgery (1)[A]
    • Elongated tendon can cause decreased plantar flexion power and endurance.
    • Preferred in elderly/inactive, poor skin integrity, systemic illness, poor wound healing, smoker
  • Traditional immobilization protocol (up to 40% rerupture rate)
    • Cast immobilization for 6 to 10 weeks
    • Short leg NWB cast in gravity equinus for 4 to 6 weeks
    • Then serial casting, gradually bringing ankle to neutral, weight-bearing allowed
    • Upon cast removal, rehabilitation and 2-cm heel lift in shoe for 2 to 4 months
  • Operative repair (see “Surgery/Other Procedures”)
    • Historically, lower rerupture rates (0–5%), possible increased postoperative muscle strength, power, endurance
    • More recent studies suggest modestly decreased rupture rates operative versus nonoperative.
    • No evidence to support claims of better functional outcome
    • Greater risk—deep infections, fistulae, necrosis of skin or tendon, sural nerve injury (percutaneous)
    • Appropriate for young/athletic patients

Medication

First Line
NSAIDs and analgesics

Issues For Referral

• Immediate surgical referral for complete rupture
• Partial rupture when >50% of tendon is affected
• Failure of conservative management
• Young athletes/surgical candidates

Additional Therapies

• Tendinopathies
  • Eccentric training (mainstay): reduced tendon thickness, decreased pain, restoration of normal architecture for midportion tendinopathies (2)[A]
  • Consider eccentric-concentric loading with eccentric for insertional tendinopathies (3).
  • Steroid injections: controversial, short-term pain relief, can weaken tendon, leading to rupture
  • Platelet-rich plasma (PRP) injections: for refractory tendinosis (4)
  • Injections should be performed under ultrasound guidance to prevent intratendinous deposition.
  • Shock wave therapy: can be helpful in combination with eccentric loading (5)[A]
  • High-volume image-guided injection is at least as effective as extracorporeal shockwave therapy for noninsertional Achilles tendinopathy (6)[B].
  • Topical glyceryl trinitrate may reduce pain with activity at night and has shown improved functional measures in one study. However, another trial did not support of this finding. Common adverse effects of topical glyceryl trinitrate include headache.
  • Short-term heel wedge use: weak evidence, can help with pain
• Rupture
  • Physical therapy after immobilization
    • Several rehabilitation protocols: gentle passive ankle range of motion → progressive resistance exercises at 2 weeks → aggressive gait training at 10 weeks → return to activities at 4 to 6 months

Surgery/Other Procedures

• Tendinopathy/bursitis
  • Surgery an option if patients fail to improve after 6 months of conservative treatment
    • Paratenonitis: removal/release of paratenon
    • Denervate and devascularize paratenon.
    • Achilles tendinosis: intratendinous débridement, retrocalcaneal bursectomy, and Haglund exostectomy
    • Augmentation or local tendon transfer if extensive disease (>50% tendon débridement)
• Rupture
  • Percutaneous: sutures reapproximate tendon, NWB cast for 4 weeks then weight-bearing low-heeled cast for 4 weeks
    • Sural nerve entrapment (up to 16%)
    • More cost-effective than open with comparable outcome
  • Open repair: reapproximate ends, ankle maintained in flexion via cast/rigid orthosis, gradually brought into neutral immobilization for 4 to 6 weeks, return to full activity within 4 months of surgery

Follow-up Recommendations

Routine follow-up until resolution of symptoms

Patient Monitoring
Achilles Tendon Total Rupture Score is the only validated outcome measure.

Patient Education

• Adherence to rehabilitation protocol is key to recovery.
• Healing times 4 to 6 months for rupture
• Stretch/strengthen calf muscles, vary exercises, increase training slowly.

Prognosis

• Tendinopathy
  • Prolonged recovery weeks to months, recurrences common
• Rupture
  • Proper treatment and rehab = good prognosis, months to recover
  • Chronic functional decrease possible but not proven

Complications

Tendinitis

• Tendon degeneration, eventual rupture
• Rupture
• If rerupture after surgical repair, poorer outcomes

ICD-10

• M76.60 Achilles tendinitis, unspecified leg
• M76.61 Achilles tendinitis, right leg
• M76.62 Achilles tendinitis, left leg
• S86.001A Unspecified injury of right Achilles tendon, initial encounter
• S86.002A Unspecified injury of left Achilles tendon, initial encounter
• S86.009A Unspecified injury of unspecified Achilles tendon, initial encounter
• S86.011A Strain of right Achilles tendon, initial encounter
• S86.012A Strain of left Achilles tendon, initial encounter
• S86.019A Strain of unspecified Achilles tendon, initial encounter
• S86.021A Laceration of right Achilles tendon, initial encounter
• S86.022A Laceration of left Achilles tendon, initial encounter
• S86.029A Laceration of unspecified Achilles tendon, initial encounter
• S86.091A Other specified injury of right Achilles tendon, init encntr
• S86.099A Oth injury of unspecified Achilles tendon, init encntr

ICD-9

• 726.71 Achilles bursitis or tendinitis
• 727.67 Nontraumatic rupture of achilles tendon
• 845.09 Other sprains and strains of ankle
• 892.2 Open wound of foot except toe(s) alone, with tendon involvement

SNOMED

• 11654001 Achilles tendinitis (disorder)
• 202917000 Achilles tenosynovitis (disorder)
• 22817005 strain of Achilles tendon (disorder)
• 301453009 tendon laceration (disorder)
• 429513001 rupture of Achilles tendon (disorder)