Clinical Features of Achilles Tendinitis
The hallmark clinical features of Achilles tendinopathy are posterior heel pain proximal to the tendon insertion, palpable tendon thickening with tender nodules, and pain exacerbated by tendon-loading activities. 1
Key Clinical Presentation
Subjective Symptoms
- Pain location: Posterior heel pain, typically 2-6 cm proximal to the calcaneal insertion 1, 2
- Pain pattern: Worse with physical activity and tendon-loading movements 3, 4
- Morning stiffness: Characteristic stiffness that worsens after prolonged rest 3, 5
- Functional limitations: Difficulty with stairs, prolonged sitting discomfort, and reduced sports/work participation 3
- Footwear issues: Discomfort wearing shoes due to heel sensitivity 3
Physical Examination Findings
On palpation, you will find:
- Tendon thickening (visible and palpable) 1, 2
- Tender, palpable nodules within the tendon substance 1
- Localized swelling 2
- Pain on direct palpation of the affected tendon segment 2, 5
On functional testing, look for:
- Pain with single-leg heel raises 2
- Pain with hopping activities 2
- Reduced ankle plantar flexion endurance (fewer heel raise repetitions compared to unaffected side) 6
- Decreased ankle dorsiflexion range of motion, particularly in non-weight bearing with knee bent 6
Associated Biomechanical Findings
Pay special attention to anatomic deformities that commonly accompany this condition 1:
- Forefoot varus
- Heel varus
- Excessive pes planus (flat feet)
- Excessive foot pronation
- Greater Achilles tendon angle 6
- Tibia varus alignment 6
- First ray and midfoot abduction laxity 6
Additional Physical Impairments
Beyond the tendon itself, examine for:
- Hip weakness: Reduced hip extension isometric strength 6
- Gluteal dysfunction: Decreased gluteus medius and maximus activity 7
- Ankle mechanics: Decreased peak ankle dorsiflexion during gait 7
- Impaired jump performance: Reduced hop test results compared to asymptomatic individuals 6
Epidemiological Context
This condition is most common in adult runners, with incidence increasing with age 1. The etiology is multifactorial, involving improper technique, anatomic misalignment, weakness, uneven training surfaces, and improperly fitted footwear 1.
Clinical Diagnosis Approach
Diagnosis is primarily clinical 3, 4. The most reliable diagnostic criteria based on accuracy and reproducibility are 5:
- Patient self-report of morning stiffness and/or pain in the tendon area
- Pain on palpation of the tendon
- Detection of Achilles tendon thickening
Imaging (ultrasound or MRI) can aid in differential diagnosis for difficult cases or when planning interventional procedures, but is not required for straightforward presentations 3, 4.
Important Clinical Distinctions
Distinguish between midportion (noninsertional) and insertional tendinopathy, as they have distinct features and different therapeutic paradigms 4. Midportion tendinopathy presents with pain 2-6 cm proximal to insertion, while insertional involves the calcaneal attachment site.
Common Pitfalls
- Don't overlook biomechanical assessment of the entire lower kinetic chain—hip and knee mechanics significantly influence Achilles loading 6, 7
- Don't miss associated anatomic deformities (pes planus, excessive pronation) that require orthotic correction 1
- Don't rely solely on imaging—this is a clinical diagnosis where imaging findings may not correlate with symptom severity 4