Article Category: review-article
Publié en ligne: 18 juin 2021
Pages: 127 - 133
Reçu: 11 févr. 2021
Accepté: 16 mars 2021
DOI: https://doi.org/10.15557/jou.2021.0021
Mots clés
© 2021 Polish Ultrasound Society. Published by Medical Communications Sp. z o.o.
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.
The Achilles tendon is the strongest and thickest weight-bearing tendon in the human body. Its origin is near the middle of the calf and is the conjoint tendon of the gastrocnemius and soleus muscles(1). The tendon does not have a true synovial sheath; instead, it is enveloped on its dorsal, lateral, and medial aspects by a paratenon composed of connective tissue that allows for approximately 1.5 cm of tendon gliding with activity(2).
Along with the patellar tendon, the Achilles is the commonest lower limb tendon to rupture, but also it is most frequently impaired as a result of overuse leading to tendinopathy(3). Chronic midportion Achilles tendinopathy is a common overuse injury that is often long-standing. Over the past three decades, the incidence has been rising because of greater participation in sports activities. Runners are most at risk of developing symptoms, with a lifetime risk of 52%(4). However, patients with this condition do not always participate in vigorous physical activity(5).
Achilles tendinopathy as a clinical syndrome is characterized by a combination of pain, swelling, and impaired performance(6). Conservative or physical therapies are established as first-line management, with eccentric loading exercises considered as the gold standard in the initial treatment(7). Despite the initiation of therapy, a significant proportion of patients continue to have symptoms even after ten years(8). About one-third of these non-responders eventually require surgery(9). Therefore, effective minimally invasive treatment options are necessary to improve the outcome of patients with chronic Achilles tendinopathy who fail to respond to the initial exercise treatment. The use of injectable substances such as platelet-rich plasma, autologous blood, polidocanol, corticosteroids, and aprotinin in and around tendons is a widespread therapeutic modality; however, there is minimal clinical evidence to support its efficacy(10). High-volume image-guided injection (HVIGI) is a relatively new procedure that has shown good short- to medium-term relief of symptoms in the management of chronic mid-substance Achilles tendinopathy(11).
High-resolution ultrasound (US) is the imaging examination of choice for assessing the Achilles tendon. The superficial location and orientation of the tendon allow excellent evaluation results(12), and the current advances in probe and scanner design enable superior visualization even of the finest anatomical details(13). On US, the normal Achilles tendon is a bright echogenic structure that typically demonstrates a compact fibrillar pattern of parallel hyperechoic lines corresponding to the collagen fiber bundles in the tendon(14). The paratenon surrounding the tendon appears as a thin echogenic line marking the edge of the tendon(15). In the current practice, there are several sonographic findings that may suggest a diagnosis of Achilles tendinopathy, including an increase in tendon caliber (particularly of the mid- and distal portions of the tendon), a disruption of the fibrillar pattern, and an increase in tendon vascularity (Fig. 1). Additional signs include increased Kager’s fat pad echogenicity and associated peritendinous adhesions, seen as thickening of the paratenon(16). Promising results for the diagnosis of Achilles tendinopathy have been demonstrated with US elastography (both compression and shear wave), with comparable or even superior accuracy to standard B mode ultrasound. However large well-designed studies are still needed to establish the suitability of this promising technique in the diagnosis of Achilles tendinopathy(17).
Fig. 1.
It has been shown that microcirculatory blood flow is significantly elevated at the site of pain in insertional and midportion tendinopathy(18). With the technological advances in color and power Doppler ultrasound, small vessel detection in musculoskeletal structures is possible with great accuracy(19). In 2001, Öhberg
Fig. 2.
The assumption behind HVIGI is that with the disruption of neovessels seen in degenerated Achilles tendons, the accompanying nerve supply is also damaged, resulting in pain reduction. Chan
Summary of published evidence for the application of HIVIGI in Achilles tendinopathy
| Author (year) | Study type | Intervention | N | Change in VAS score | Change in VISA-A score | Conclusion |
|---|---|---|---|---|---|---|
| Chan |
Case series | 10 ml 0.5% Bupivacaine |
30 | N = 21 |
30 weeks + 31.4 | HVIGI significantly reduces pain and improves function in patients with resistant Achilles tendinopathy in the short- and long-term |
| Humphrey |
Case series | 10 ml 0.5% Bupivacaine |
11 | – | 3 weeks + 38 | HVIGI for resistant tendinopathy of the main body of the Achilles tendon is effective to improve symptoms, reduce neovascularisation, and decrease maximal tendon thickness at short-term follow-up |
| Restighini and Yeoh (2012)(30) | Case series | 5 ml 1% Lidocaine |
32 | 4 weeks – 34 mm |
4 weeks + 26 |
HVIGI is safe and clinically cost-effective in the treatment of Achilles tendinopathy. Results suggest that baseline neovascularity is relevant to outcome following injection |
| Maffuli |
Case series | 10 ml 0.5% Bupivacaine |
94 | – | 12 months + 32.9 | HVIGI with aprotinin significantly reduces pain and improves function in patients with chronic Achilles tendinopathy in the short-and long-term follow-up |
| Wheeler |
Case series | 10 ml 1% Lidocaine |
16 | 347 days ‒ 6.1/10 | 347 days + 41 | HVIGI without a corticosteroid appears to be an effective procedure for patients with recalcitrant Achilles tendon symptoms. Further work is needed to formally establish benefits from HVIGI for patients with Achilles tendinopathy and to identify optimal injectate |
| Wheeler |
Case series – 2 Groups |
|
34 |
|
|
HVIGI reduces VISA-A scores in both groups. A higher volume without dry needling compared with a lower volume with dry needling resulted in greater improvement in noninsertional Achilles tendinopathy |
| Boesen |
Case series – 3 Groups | All subjects performed eccentric training |
60 |
|
|
Treatment with HVIGI or PRP in combination with eccentric training in chronic AT seems more effective in reducing pain, improving activity level, and reducing tendon thickness and intratendinous vascularity than eccentric training alone. HVIGI may be more effective in improving outcomes of chronic AT than PRP in the short term |
| Boesen |
Case series –2 Groups | All subjects performed eccentric training |
28 |
|
|
High-volume injection with or without corticosteroid in combination with eccentric training seems effective in AT. HVIGI with corticosteroid showed a better short-term improvement than HVIGI without corticosteroid, indicating a short-term effect of corticosteroid in HVIGI treatment of AT |
| Nielsen |
Case series | 10 ml 0.5% Marcaine |
30 | – | 12 months |
In this retrospective case-study, only 10 patients (33%) benefitted from a single HVIGI treatment at 12 months and an 11-point significant improvement was seen on the VISA-A score |
| Edwards and Sivan (2020)(37) | Case series | 2 ml 0.25% Bupivacaine |
18 | Numeric rating scale of pain (NRS) 8 weeks – 5.3 | – | Significant reduction in pain, tendon thickness and neovascularity were observed in 78% of patients. The recurrence rate was 39%. HVIGI with eccentric training is a safe and effective intervention in an outpatient clinic setting |
Through the consent process, it is a standard procedure to discuss with the patient the (low) likelihood of bleeding, infection and injury to adjacent neurovascular structures in addition to the possible adverse effects associated with corticosteroid use: post-injection flare, local tissue atrophy, tendon rupture, flushing, and transient increased blood glucose level(40,41). Coagulation laboratory tests are not usually necessary prior to the injection due to the low risk of bleeding(42).
To ensure patient comfort and optimal visualization of the anatomy, the patient is prone, with the foot hanging over the edge of the table (Fig. 3A). Gentle dorsiflexion of the ankle and the use of sterile transmission gel help optimize imaging(43). A preliminary diagnostic scan using a linear high frequency (7–12 MHz) ultrasound probe should be performed before the procedure to document the baseline appearance of the abnormality, detect areas of increased neovascularity as target areas, locate any adjacent neurovascular structures to be avoided, and plan the optimal needle entry point and route to the target site(44). The ideal injection site is at the level of the thickest portion of the tendon with the most significant degree of neovascularity. Using a skin marker, a dot for the ideal needle entry point may be drawn.
Fig. 3.
The injection area is sterilized using an iodine-based solution. The transducer is also immersed in an iodine-based solution and surrounded by a sterile cover. A sterile gel must be used, if necessary.
The following injectables and dosages are the author’s preferred choice, based on published evidence and experience. A 10 ml syringe is typically used with a 25 G needle (blue), filled with 1% lidocaine for regional anesthesia, a 10 ml syringe with a 21 G needle (green) filled with 1 mL of 40 mg/mL methylprednisolone or an equivalent corticosteroid and 9 ml of a long-acting anesthetic, typically 0.5% bupivacaine, and two 20 ml syringes with an extension tube filled with normal saline 0.9%.
At our institution, the injection is routinely performed using a freehand in-plane technique(45). The ultrasound probe is held transversely relative to the Achilles tendon. A medial approach is used to minimize the risk of injuring the sural nerve(46) (Fig. 3B). First, lidocaine is injected into the skin, and subcutaneous and deep tissues. After local anesthesia is achieved, the 21 G needle with the syringe containing the mixture of methylprednisolone and bupivacaine is inserted parallel to the long axis of the ultrasound probe and – under continuous observation – is guided deep to the tendon between the tendon and the Kager’s fat pad (Fig. 4), targeting the area of maximal neovascularization. Once the first syringe is injected and removed, the extension tube is connected to the needle, and the syringes containing 40 ml of normal saline are injected at the same location. Constant visualization of needle position confirms proper placement, providing continuous monitoring of the distribution of the administered agents, and ensuring that no unwanted structures are injured or injected(47).
Fig. 4.
After the needle is removed, a post-injection scan is performed (Fig. 5). Pressure is applied at the puncture site, and the area is covered with a small bandage. The patient is advised to rest and avoid movements for two days. Paracetamol and ice packs are recommended, if necessary. An eccentric loading exercise program is recommended after three days following the procedure with gradually increasing intensity as pain allows(48).
Fig. 5.
The management of Achilles tendinopathy remains a major challenge. Based on the relative limited published data in conjunction with our department’s experience, HVIGI seems to be a safe, fast, relatively inexpensive, minimally invasive technique with a great potential for the treatment of chronic mid-substance Achilles tendinopathy. This treatment approach has been shown to significantly reduce pain and improve short- and long-term function in patients regardless of the severity of their symptoms(28,34). It works well in combination with conservative treatments, especially eccentric loading exercises(48). It has a very low complication rate and any serious complication has yet to be reported. HVIGI should be considered as an option before surgery when other conservative or minimally invasive methods have failed. Surgery, in addition to an increased rate of complications, is more expensive and requires an extended period of rehabilitation prior to the patient being able to return to sports or routine physical activities. With HVIGI, we can document the abnormality and perform the procedure within one patient visit.
The majority of published studies report positive results, but almost all lack control groups and are limited by the small number of included patients. There are also differences in the duration of follow-up between studies, discrepancies in outcome measurements, and variations in the injectable drugs and doses, making the results of this group of studies challenging to interpret (a detailed presentation of the available literature and the outcomes of existing studies is presented in Tab. 1). Discrepances in study design have led to a great variability in reported treatment efficacy, ranging from 18.1 mm to 61 mm of VAS score reduction(32,34). Nonetheless, irrespective of quantitative data, the majority of published studies report a significant benefit in treated patients.
Work is still needed to optimize the technique and systematically compare to outcomes of conservative and surgical treatments over a long follow-up course. There is still no consensus as to the optimal content and volume of the solution used to achieve desired effects. Therefore, more good-quality randomized controlled trials including a larger number of patients with a non-injected control group matched for age, sex and physical activity with longer-term follow-up are still required to further determine the value of HVIGI in the treatment of Achilles tendinopathy. Other US-guided treatment options for Achilles tendinopathy include sclerotherapy for obliterating the neovessels, corticosteroid injections, and intratendinous hyperosmolar dextrose injections (prolotherapy). However, the need for multiple treatment repeats with sclerotherapy and corticosteroids, the association of corticosteroid intratendinous injections with Achilles ruptures, and the lack of evidence for the efficacy of prolotherapy have significantly limited their clinical use(49,50).
In conclusion, HVIGI presents an effective treatment option for patients with Achilles tendinopathy, potentially offering a significant pain improvement when traditional conservative measures have failed. Work is still required to further optimize the technique and acquire long-term follow-up treatment outcome data. However, existing data already indicate that HVIGI might be the treatment of choice in patients with persistent Achilles tendinopathy as a safe and effective way of delaying or even avoiding surgery.