What is the diagnosis and management for a patient presenting with Achilles tendon tenderness, possibly due to overuse injury or underlying conditions like tendonitis or bursitis?

Diagnosis of Achilles Tendon Tenderness

Achilles tendon tenderness is diagnosed clinically through a focused history revealing insidious onset of load-related posterior heel pain aggravated by activity, combined with physical examination findings of well-localized tenderness on palpation, tendon thickening, and pain reproduction with tendon loading maneuvers. 1

Clinical History

The typical presentation includes:

• Insidious onset of chronic posterior heel pain and swelling that worsens with increased activity and pressure from shoes 1
• Load-related pain that initially occurs during activity but may subside after warm-up in early stages, progressing to constant pain at rest in later stages 2
• Pain described as "sharp" or "stabbing" in quality 2
• History of new activity or increased intensity of current activity preceding symptom onset (though not always present) 2
• Relief when walking barefoot is common in insertional Achilles tendinitis 1

Physical Examination

The diagnosis is primarily clinical and relies on specific examination findings:

Inspection

• Swelling, erythema, and asymmetry are commonly noted with pathologic tendons 2
• Muscle atrophy suggests chronic condition and provides clues to duration 2
• Prominence medially and laterally to the Achilles tendon insertion 1
• Joint effusions are uncommon and suggest intra-articular pathology rather than tendinopathy 2

Palpation

• Well-localized tenderness similar in quality and location to activity-related pain 2
• Central or global tenderness at the tendon 1
• Tendon thickening and palpable nodules 1

Functional Testing

• At least two specific tests should be performed, including Thompson test, assessment of decreased ankle plantar flexion strength, palpation for gaps or defects, and evaluation of increased passive ankle dorsiflexion 1
• Physical maneuvers that simulate tendon loading should predictably reproduce the patient's pain, supporting the diagnosis 2
• Limited range of motion on the symptomatic side 2

Anatomic Assessment

• Evaluate for anatomic deformities such as forefoot and heel varus, excessive pes planus, or foot pronation 1

Imaging Studies

Imaging is reserved for specific situations and is not required for initial diagnosis:

When to Order Imaging

• Diagnosis remains unclear after thorough history and physical examination 2, 1
• Recalcitrant pain despite adequate conservative management 2, 1
• Preoperative evaluation 2, 1

Plain Radiography

• May show calcific tendinosis, calcaneal avulsion fracture, and soft-tissue swelling 2
• Useful to identify spurring or erosion at the Achilles tendon insertion in insertional tendinitis 1
• Can reveal other bony abnormalities that may cause symptoms 1

Ultrasonography

• Demonstrates tendon thickening and heterogeneous echogenicity 2, 1
• Shows decreased echogenicity and calcification of the tendon 1

MRI

• Sensitive (95%) and specific (95%) for detecting chronic degenerative changes, partial tears, and tendon thickening 1
• Useful for showing partial tendon tears, tendon thickening, bursitis, and chronic degenerative changes 2

Differential Diagnoses to Consider

Multiple symptomatic tendons should alert you to consider rheumatic disease or warrant rheumatologic referral 2

Key differential diagnoses include:

• Retrocalcaneal bursitis 1
• Haglund's deformity 1
• Achilles tendon rupture 1
• Neurologic causes of heel pain 1
• Paratenonitis 3
• Insertional tendinitis 3

Critical Diagnostic Terminology

The condition should be labeled as "tendinosis" or "tendinopathy" rather than "tendonitis" because most patients presenting to primary care have chronic symptoms suggesting degenerative changes rather than acute inflammation 2, 4. While acute inflammatory tendinopathies exist, by the time patients present to a family physician, acute inflammation has typically subsided and been replaced by degeneration of the normally arranged collagen fiber structure 2.

Common Diagnostic Pitfalls

• Excessive swelling and pain can limit examination in acute cases, potentially masking the diagnosis 1
• Relying solely on imaging when clinical diagnosis is sufficient wastes resources and delays treatment 2
• Mislabeling as inflammatory "tendonitis" leads to inappropriate anti-inflammatory focused treatment when the underlying pathology is degenerative 2, 4