Lower-limb Tendinopathy Diagnosis

Diagnosis

General principles 
Six critical principles determine when the source of symptoms is the tendon. They include:
1.    Provocative activities align with known activities to aggravate the tendon,
2.    There is a clear warm-up phenomenon with exercise,
3.    Symptoms (e.g., stiffness) are worse the day following provocative exercise,
4.    Increased tendon load of exercises is more provocative for symptoms,
5.    Single-leg loading is more provocative than double-leg loading, and 
6.    Pain remains localized when provoked and does not move or spread.

Subjective assessment

The subjective assessment for people with suspected tendinopathy revolves around ruling out inflammatory pathologies masquerading as tendinopathy (e.g., psoriatic arthritis) and ensuring the patient’s symptoms align with the known behaviors of tendinopathy. Clinicians must ensure that: 1) provocative activities align with known activities to aggravate the tendon, 2) there is a clear warm-up phenomenon with exercise, and 3) symptoms (e.g., stiffness) are worse the day following provocative exercise.

1. Provocative activities align with known activities to aggravate the tendon
It is imperative that in the subjective assessment, clinicians must determine the activities that are most likely to aggravate a patient’s tendon (see table 1). In just a few words, the patients can essentially allow the clinician to rule out a diagnosis of tendinopathy. This is possible as only tensile and compressive loading contributes to tendinopathy. Thus, if patients’ primary complaints are provocative loads, most commonly due to shear forces, the clinician can be confident they are unlikely to have tendinopathy. For example, suppose an athlete presented with pain in the Achilles tendon region that was predominantly aggravated by cycling or rowing (shear forces). In that case, the clinician can confidently rule out an Achilles tendinopathy diagnosis. Similarly, suppose a marathon runner presents with anterior knee pain most aggravating during their long, steady-state runs. In that case, the clinician can be confident they are unlikely to have tendinopathy, given that running is not a high-tendon load for the patellar tendon.

Table 1: Provocative loads for lower-limb tendons

2. There is a clear warm-up phenomenon with exercise
One of the hallmark signs of tendinopathy is a warm-up effect with loading. This means that when someone starts exercising, they may have some tendon pain. However, this should be reduced as they continue to perform their exercise. If someone is not experiencing a warm-up phenomenon, and their pain gradually worsens when performing exercise, it is highly unlikely that their primary source of symptoms is the tendon.

3. Symptoms (e.g., stiffness) are worse the day following provocative exercise
The final indicator from a patient’s history that will indicate to the clinician that their tendon is the source of their symptoms is that they will feel worse the day following provocative exercise. Tendinopathy patients often report feeling good the day they perform aggravating exercise as they have warmed up. The next day, particularly when they wake up, they notice their tendon is very stiff. If the patient does not experience a clear increase in the stiffness or tightness of their tendon the day following provocative loading, it is again unlikely that they have tendinopathy.

Objective assessment

The objective assessment for people with tendinopathy revolves around three pain assessments: 1) increased tendon load of exercises is more provocative for symptoms, 2) single-leg loading is more provocative than double-leg loading, and 3) the pain remains localized when provoked and does not move or spread (see figure 2).

1. Increased tendon load of exercises is more provocative for symptoms
The first method to assess whether a patient’s pain is ‘load dependent’ is to have them perform progressively more challenging exercises and assess whether pain worsens as load increases. For example, in the Achilles tendon, a clinician can ask a patient for the severity of their pain with a double-leg calf raise, pain severity with a single-leg calf raise, and then double-leg jumping followed by single-leg hopping (stretch-shorten cycle). In Achilles tendinopathy, jumping and hopping would be expected to be painful.

2. Single-leg loading is more provocative than double-leg loading
The second essential assessment is ensuring that single-leg loading is more provocative than double-leg loading, as single-leg loading increases the load upon the tendon. Using the examples provided above, single-leg calf raises or hopping in the Achilles should be more painful than the double-leg. Meanwhile, in the patellar, single-leg squats and single-leg jumping should be more painful than the pain recorded with double-leg tasks.
 
3. Pain remains localized when provoked and does not move or spread
Once a clinician determines the pain severity, they must also determine the pain location to ensure the pain does not move or spread. Tendon pain is localized. It will not be the source of pain for symptoms that move around or spread. Furthermore, clinicians must determine the pain location during the objective loading task assessment, as a patient’s ability to recall the pain site is unreliable. Researchers at La Trobe University in Australia demonstrated that ~55% of people with Achilles pain report different pain regions on recall compared to when the tendon is actively loaded⁽¹⁰⁾.

The role of palpation and imaging

Clinicians use imaging and palpation in research and clinical practice to assist with the tendinopathy diagnosis^(11,12). However, their specificity is questionable when assessing tendinopathy.

Imaging
Imaging is an invaluable component of our current healthcare system. However, clinicians must recognize the benefits and limitations of musculoskeletal imaging, as asymptomatic pathology on imaging is very common for musculoskeletal diseases (particularly tendons)^(9,13). As tendinopathy is a clinical diagnosis, clinicians do not need imaging to confirm the diagnosis. This also makes sense when the specificity of imaging in tendinopathy is relatively poor (e.g., poor capacity to rule in a diagnosis due to how common asymptomatic pathology can be). However, the sensitivity of imaging in tendinopathy is excellent (e.g., excellent capacity to rule out a diagnosis of tendinopathy if imaging is normal). Therefore, clinicians must view imaging in light of its strengths and limitations so that instead of using it to ‘confirm’ a clinical diagnosis, only use it to rule out a tendinopathy diagnosis when the imaging is normal.

Palpation 
Palpation suffers from the same limitations as musculoskeletal imaging (poor specificity, excellent sensitivity). Unfortunately, tendons often become sensitized in the presence of nearby chronic pain conditions (e.g., the patellar tendon becomes sensitized in knee osteoarthritis), and if relying on palpation tenderness to make a diagnosis, you can often go wrong. For example, less than one-third of people with palpation pain on the inferior patellar pole actually have patellar tendinopathy⁽¹⁴⁾. Instead, due to its excellent sensitivity, clinicians must only use palpation to rule out a diagnosis of tendinopathy⁽¹⁵⁾. For example, tendinopathy is unlikely if the tendon is not painful on palpation.

Diagnosis Essentials

Diagnosing lower-limb tendinopathy can seem complicated, but if clinicians stick to the six essential criteria to confirm the tendinopathy diagnosis (see figure 3), it will be much simpler!

References

1. Br J Sports Med. 2020;54(5):260-62. 
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9. J Orthop Sports Phys Ther. 2021;51(5):232-52. 
10. J Orthop Sports Phys Ther. 2024. Epub Ahead of Print.
11. Sports Med. 2022;52(3):613-641.  
12. BMJ Open Sport Exerc Med 2022. 20;8(2):e001355
13. J Orthop Sports Phys Ther. 2024: Epub Ahead of Print.
14. Clinics. 2009;64(3):199-202. 
15. Foot Ankle Surg 2013;19(2):112-7.