Introduction
Gait is an essential function for performing daily activities and serves as a key determinant of quality of life1). Among the various conditions that significantly affect gait and overall mobility, Achilles tendinopathy is the most common2). Achilles tendinopathy is clinically defined as a syndrome characterized by activity-induced pain, swelling, and functional impairment. Previous studies have identified repetitive microtrauma, increased mechanical load, and reduced vascular supply as major contributing factors. In particular, individuals subjected to prolonged physical activity or occupational stress are at an increased risk owing to the continuous mechanical strain placed on the Achilles tendon3). This condition occurs not only in athletes but also in the general population4).
Without appropriate treatment, Achilles tendinopathy can progressively worsen, leading to alterations in ankle joint movement patterns. One such alteration is the development of “medial collapse,” a condition in which the ankle fails to maintain proper alignment during activities such as walking or running, resulting in inward deviation5). These changes in the gait mechanics may cause secondary musculoskeletal imbalances and affect the knee, hip, and lumbar spine5). Although not life-threatening, such gait disturbances can lead to significant impairment in mobility and a substantial decline in the quality of life2).
Treatment of Achilles tendinopathy can be broadly categorized into conservative and surgical approaches. However, there is no consensus on the best treatment strategy and there is considerable debate regarding optimal management. Conservative treatments include nonsteroidal anti-inflammatory drugs, cryotherapy, eccentric exercise, extracorporeal shockwave therapy, and injection therapy; however, no single modality has been shown to be definitively superior6). According to previous studies, up to 45.5% of patients who undergo conservative treatment fail to achieve satisfactory outcomes. Surgical intervention may be considered in cases where symptoms persist for approximately six months despite conservative management. However, in patients with long-standing tendinopathy, postoperative outcomes are often suboptimal and the likelihood of requiring revision surgery is relatively high6). These limitations underscore the need for novel treatment approaches based on the pathophysiology of Achilles tendinopathy. To overcome these challenges, a comprehensive management strategy that targets the multifactorial nature of this condition is warranted. Current conservative therapies often focus on a single pathological mechanism—such as inflammation, mechanical load, or neovascularization—resulting in limited efficacy when applied in isolation6). Therefore, combining multiple evidence-based modalities may offer synergistic therapeutic benefits. The approach presented in this study integrates existing techniques into a structured, four-stage treatment sequence designed to address paratenon inflammation, fascial restriction, neovascularization, and tendon degeneration simultaneously. This integrated strategy is particularly relevant for chronic cases that have not responded to standard monotherapies.
Accordingly, we applied this four-stage ultrasound-guided acupuncture approach to a patient with a five-year history of Achilles tendinopathy who had not improved after more than six months of conservative care and was subsequently recommended for surgical intervention. The treatment protocol consists of the following four stages: (1) management of paratenonitis, (2) fascial release between the gastrocnemius and soleus muscles using pharmacopuncture, (3) removal of neovascularization through high-volume injection (HVI), and (4) periosteal pecking technique and high-frequency electroacupuncture targeting the periosteum at Achilles tendon insertion. This case report was prepared in accordance with the CARE guidelines and aimed to highlight the potential of this four-stage protocol as a nonsurgical therapeutic option for chronic Achilles tendinopathy.
Case Presentation
1. Ultrasound-Guided Four-Stage Treatment Procedure
Stage 1: Bee Venom Pharmacopuncture for Paratenonitis
1) Target Tissue and Pathophysiological Rationale
The primary therapeutic target in chronic Achilles tendinopathy is the paratenon, the tissue surrounding the tendon. This is due to the inherent lack of vascular supply and the absence of a synovial sheath in the Achilles tendon, making it less prone to developing a true inflammatory response. While most tendons are enveloped by a synovial sheath, the Achilles tendon lacks this feature because of its straightforward course and structural characteristics. Instead, it is surrounded by a paratenon, a rich vascularized connective tissue layer that supplies oxygen and nutrients to the tendon. In chronic Achilles tendinopathy, pain is thought to originate primarily from the inflammation of the paratenon, which contains abundant nociceptors and blood vessels. Therefore, paratenonitis is the key pathophysiological focus in the management of chronic Achilles tendinopathy3).
2) Anti-inflammatory Mechanism of Bee Venom Pharmacopuncture
The primary active component of bee venom is melittin, which exerts significant anti-inflammatory effects. Its mechanism of action involves modulation of inflammatory signaling pathways, particularly through the inhibition of nuclear factor-kappa B (NF-kB) and mitogen-activated protein kinases (MAPKs). Melittin reduces the expression of pro-inflammatory cytokines by downregulating these pathways7). However, owing to the potential for severe allergic reactions, such as anaphylaxis, it is essential to assess for any previous hypersensitivity to bee venom, as well as relevant family history, before initiating bee venom pharmacopuncture8).
3) Procedure Protocol and Precautions
The patient is placed in the prone position, and a transverse ultrasound scan is performed at the most tender point near the Achilles tendon insertion using a Logiq Fortis ultrasound device (General Electric Co., Seongnam, Korea) with a high-frequency hockey stick L 6-24 probe (24 MHz). A 27gauge-25 mm needle is inserted from the lateral aspect through the Kunlun (BL60) acupoint. The bee venom solution consisted of 0.5 mL of sterile purified sweet bee venom mixed with sterile normal saline (2.5 mL) for a total volume of 3.0 mL. As the needle advances, the solution is gradually injected, and the spread of the bee venom along the paratenon in a reverse U-shaped pattern is visualized under ultrasound guidance (Figure 1).
After the injection, the patient remains in the waiting area for 15 minutes for observation. Before discharge, the patient is educated on the signs of anaphylaxis and appropriate response measures. Approximately 90% of anaphylactic reactions occur within minutes, typically within 2 minutes, after allergen exposure. The early signs include erythema, flushing, pulse loss, impaired lung expansion, decreased end-tidal CO2, and reduced oxygen saturation8).
Stage 2: Polydeoxyribonucleotide Hydrodissection of the Gastrocnemius-Soleus Intermuscular Fascia
1) Target Tissue and Pathophysiological Rationale
The second therapeutic target in the treatment of chronic Achilles tendinopathy is the intermuscular fascia between the gastrocnemius and soleus muscles. As Achilles tendinopathy progresses, the elasticity of the Achilles tendon decreases, resulting in the impaired transmission of mechanical force during walking and daily activities. To compensate for this, hypertonicity and shortening of the gastrocnemius and soleus muscles may occur9).
Because both muscles are inserted into the calcaneus via the Achilles tendon, their shortening can exert continuous tensile stress on the tendon. This mechanical overload may contribute to the development of myofascial pain syndrome (MPS) during tendon insertion10). Previous studies have shown that nociceptors are more densely distributed in the fascia than in muscle tissue and that increased fascial tension is associated with increased pain sensitivity11). Therefore, myofascial pain resulting from fascial hypertonicity in the gastrocnemius-soleus complex is likely to be a significant source of pain in patients with chronic Achilles tendinopathy.
2) Polydeoxyribonucleotide (PDRN)
Although hydrodissection is commonly performed using normal saline or 5% dextrose solutions12), this protocol employs PDRN as an alternative injectate. PDRN binds to adenosine A2 receptors, promoting the synthesis of vascular endothelial growth factor (VEGF) and stimulating fibroblasts to produce collagen fibers. As a result, PDRN facilitates the physical separation of fascial adhesions and enhances the regeneration of damaged fascia and surrounding soft tissues. Importantly, the angiogenic effects of PDRN promote the formation of physiologic microvasculature, which supports tissue repair, and are distinct from the pathologic neovessels associated with chronic tendinopathy. This dual action may offer superior therapeutic benefits compared with conventional hydrodissection agents13).
3) Procedure Protocol and Precautions
The patient is placed in the prone position. Palpation is performed to identify the most tender point between the gastrocnemius and the soleus muscles, which are typically located at the medial head of the gastrocnemius. Once the tender point is identified, the ultrasound probe (ML6-15 probe, 14 MHz) is positioned over the area, and the needle is inserted from the lateral side. A 27 gauge – 38 mm needle is used, and 3.0 mL of PDRN is gradually injected into the intermuscular fascia between the gastrocnemius and soleus to perform controlled hydrodissection (Figure 2). Care must be taken to avoid inadvertent injections into the plantaris tendon, which runs between the two muscles.
Stage 3: Destruction of Neovessels in the Achilles Tendon Using High-Volume Injection
1) Target Tissue and Pathophysiological Rationale
From the third stage onward, the treatment directly targets the pathological changes within the Achilles tendon. Due to the inherently poor vascular supply of the tendon, chronic Achilles tendinopathy often results in ischemic hypoxia3).
As a compensatory response to this hypoxic state, neovascularization occurs frequently and is accompanied by the ingrowth of sensory nerve fibers. The proliferation of these sensory nerves along newly formed blood vessels increases sensitivity to inflammatory stimuli and contributes to mechanical entrapment and persistent pain. This pathophysiological process is referred to as “neurogenic inflammation and is induced by neovascularization”6).
To address this, a HVI of 50 mL of placental pharmacopuncture solution is administered. HVI is a technique that has already been employed in conventional medicine as a conservative treatment for patients with chronic Achilles tendinopathy who do not respond to standard therapies6). This procedure aims to disrupt the intratendinous neovessels and simultaneously release sensitized sensory nerves through hydrorelease, thereby alleviating pain and inflammatory hypersensitivity.
2) Placenta Pharmacopuncture Solution
The primary objective of HVI at this stage is the elimination of neovessels. The placental pharmacopuncture solution contains various growth factors including VEGF, epidermal growth factor (EGF), and fibroblast growth factor (FGF), which facilitate both the removal of abnormally formed neovessels and the promotion of physiological tissue regeneration. Additionally, previous studies have demonstrated that placental extracts promote neuroprotection and myelin repair, contributing to the attenuation of neural sensitization under inflammatory conditions14). Unlike corticosteroids, which may cause tendon degeneration and delayed healing, or local anesthetics, which can induce neurotoxicity or temporary motor impairment, placental pharmacopuncture has a significantly lower risk of such adverse effects6,14). These combined effects make placental pharmacopuncture a suitable agent for the treatment of HVI in patients with chronic Achilles tendinopathy.
3) Procedure Protocol and Precautions
The patient is positioned in the prone position. The Achilles tendon is scanned using an ultrasound probe to identify the region with the most prominent neovascular signals using color Doppler imaging. A high-frequency hockeystick L 6-24 probe (18 MHz) is placed transversely at the identified site, and a 27 gauge – 25 mm needle is inserted in-plane.
Because of the potential obscuration of the needle tip caused by moving Doppler signals during fluid injection, the procedure is performed in dual mode, which allows simultaneous visualization using B-mode and color Doppler. The placental pharmacopuncture solution is injected at a high volume between the deep epitenon of the Achilles tendon and the Kager fat pad. The hydrostatic pressure generated by injection is intended to mechanically disrupt the neovessels.
To minimize procedural discomfort, the injection is initiated at a volume of approximately 12 mL. The volume is gradually increased in subsequent sessions, eventually reaching 50 mL, as tolerated by the patient (Figure 3).
Stage 4: Periosteal Pecking Technique at the Achilles Tendon Insertion Site and High-frequency Electroacupuncture
1) Target Tissue and Pathophysiological Rationale
The fourth stage of treatment involves the stimulation of the periosteum at Achilles tendon insertion to induce localized microbleeding and inflammatory responses, thereby promoting tendon remodeling. The periosteum is a highly vascularized connective tissue with a richer blood supply than the tendon itself15). Periosteum stimulation enhances local blood flow, which may improve the reparative capacity of the tendon, particularly in the context of ischemic hypoxia15,16).
Collagen degeneration is a primary pathological mechanism underlying Achilles tendinopathy16). Mechanical stimulation of the periosteum via periosteal pecking technique induces controlled microtrauma, which activates a local inflammatory cascade and promotes the activity of fibroblasts and osteoblasts17). This process facilitates collagen remodeling, contributing to the structural recovery of tendons and improving their functional integrity.
2) High-frequency Electroacupuncture (100 Hz)
High-frequency electroacupuncture (HFEA) is a widely used nonsurgical intervention for musculoskeletal and tendinous disorders. This technique involves the insertion of acupuncture needles into pathological tissues, followed by the application of alternating electrical stimulation at frequencies typically above 80 Hz. HFEA has been shown to reduce peripheral sensitization and produce analgesic effects through segmental and supraspinal neuromodulation18).
Such stimulation can improve local blood circulation, modulate inflammatory responses, and suppress aberrant nociceptive signaling. Additionally, the mechanical microtrauma caused by needle insertion may activate fibroblasts and promote collagen remodelling and tissue regeneration. These combined effects support the therapeutic potential of HFEA in treating chronic tendinopathy and related musculoskeletal pain syndromes18).
3) Procedure Protocol and Precautions
The patient is placed in the prone position. A longitudinal scan of the Achilles tendon insertion is performed using a hockeystick L 6-24 probe (24 MHz). Under ultrasound guidance, two 27 gauge – 38 mm needles are inserted into the periosteum at the tendon insertion site. Electrical stimulation is applied at a frequency of 100 Hz for 3 s at an intensity sufficient to elicit a needling sensation (deqi). This procedure is repeated thrice (Figure 4).
2. Patient History
A 49-year-old woman, 156 cm tall and weighting 63 kg (body mass index 25.9 kg/m2), presented with a five-year history of left heel pain. She was employed as a restaurant worker, requiring prolonged standing and walking periods throughout the day. She had been diagnosed with Achilles tendinopathy accompanied by calcific tendinitis at an orthopedic clinic and had undergone nine sessions of triamcinolone-lidocaine injections and ten sessions of platelet-rich plasma injections, with minimal clinical improvement. Despite more than six months of conservative management, her symptoms persisted and were accompanied by calcific deposits and significant functional impairment in daily life. Based on these factors, surgical intervention was recommended.
While searching online for alternative treatment options, she encountered a blog article on ultrasound-guided acupuncture and visited our clinic. At the time of presentation, she was not taking any medications. During the initial visit (Day 0), the patient reported the symptoms with the following quote: “The pain is extremely sharp when I take my first step after getting out of bed in the morning. It also catches me off guard when I change posture after standing for a long time. The pain is localized to the left heel and feels like a stabbing sensation. Since I work at a restaurant, I am on my feet all day, either standing or walking. The pain seems to be getting worse over time.”
An Magnetic Resonance Imaging (MRI) scan obtained at the previous hospital is presented in Figure 5, and ultrasound images obtained at our clinic on the day of the initial visit are shown in Figure 6.
Figure 5. MRI Findings of the left ankle in the patient with Achilles tendinopathy and calcific enthesopathy. Proton density-weighted (PD SPIR) sagittal and axial MRI images of the left ankle demonstrate insertional thickening of the Achilles tendon with irregular signal intensities suggestive of chronic tendinosis. Notably, hypointense calcific foci are identified near the tendon’s insertion site on the calcaneus, consistent with calcific enthesopathy. Mild thickening of the surrounding paratenon may indicate associated paratenonitis. These findings are consistent with insertional Achilles tendinopathy with concurrent calcific change.
3. Treatment and Evaluation
The patient underwent 12 treatment sessions over a period of 47 days. Stage 1 and Stage 2 treatments were administered concurrently on days 1, 4, 8, and 13 for a total of four sessions. Stages 2 and 3 treatments were then combined and applied on days 18, 22, 25, 29, 34, and 39 for a total of six sessions. Stage 4 treatment was performed twice: once on day 43 and once on day 47.
The pharmacopuncture solutions used in each stage were as follows: Sweet Bee Venom safe (1%) for Stage 1, PDRN extracted and purified from salmon deoxyribonucleic acid for Stage 2, and human placenta extract for Stage 3.All pharmacopuncture solutions were prepared by AJ External Herbal Dispensary (Republic of Korea).
In all stages, 27-gauge disposable injection needles (Sungshim, Republic of Korea) were used. Stage 4 involved HFEA using the STN-111 device (Stratek, Republic of Korea), a low-frequency electrotherapy stimulator commonly used in Korean medicine clinics. The device delivered alternating pulsed current at a frequency of 100 Hz.
Treatment efficacy was evaluated at five time points: baseline (day 0), upon completion of stages 1 and 2 (day 13), upon completion of stages 2 and 3 (day 39), upon completion of stage 4 (day 47), and at a follow-up visit approximately two months after treatment completion (day 118). Clinical outcomes were assessed using Foot and Ankle Outcome Score (FAOS).
The FAOS is a self-reported questionnaire designed to assess foot and ankle related symptoms and functional limitations. It consists of five subscales: (a) pain, (b) other symptoms, (c) function in daily living, (d) function in sports and recreational activities, and (e) quality of life. Each item is rated on a 5-point Likert scale (0–4), and subscale scores are converted to a 0–100 point scale using an inverted normalization formula, where higher scores indicate better function and fewer symptoms19).
Result
1. Intervention adherence and Adverse events
The patient demonstrated high adherence to the intervention protocol and attended all scheduled treatment sessions without any deviations. Throughout the treatment period, no adverse events or unexpected symptoms were reported, indicating a good overall tolerability.
2. Ultrasound evaluation
Compared to day 0, a marked reduction in the color Doppler signal intensity was observed by day 47 (Figure 7). However, there were no significant changes in Achilles tendon thickness or the size of the calcific deposits.
3. Foot and Ankle Outcome Score
Changes in the FAOS over the course of treatment are presented in Table 1.
5. Patient Perspective
Day 0 (initial visit)
“I had received multiple injection treatments at an orthopedic clinic over the past five years, but none provided meaningful relief. My doctor told me that if the injections were ineffective, surgery would be the next option. Before considering surgery, I wanted to try Korean medical treatment and decided to visit the clinic.”
Day 4 (2nd visit)
“The sharp pain I used to feel when stepping on and off my foot disappeared two days ago. However, since yesterday, I have felt a burning pain around my Achilles tendon again.”
Day 13 (4th visit)
“The pain in my Achilles tendon has decreased significantly. The stinging and prickling sensations in the skin over my heel have also improved.”
Day 39 (11th visit)
“I no longer experience significant pain in daily life. However, when I stand for more than four hours, I still feel tightness and a pulling sensation around the Achilles tendon.”
Discussion
This study presents a case report in which a pathophysiology-based, four-stage, ultrasound-guided acupuncture treatment strategy was applied as a conservative treatment for chronic Achilles tendinopathy. The patient did not respond to over six months of conventional conservative therapies and had been recommended for surgical intervention. Instead, she received the proposed treatment in 12 sessions over a period of 47 days. Following treatment, a marked reduction in the intratendinous color Doppler signal was observed on ultrasonography, and significant improvements were noted across the FAOS subscales, indicating reduced symptoms and enhanced function. At a follow-up visit approximately two months after the final session, the therapeutic effects were maintained without symptom recurrence.
The four-stage treatment approach used in this study was structured based on clearly defined therapeutic goals for each stage. All interventions were performed under ultrasound guidance to ensure precise targeting of the pathological area.
The objective of stage 1 is to control paratenonitis, the primary source of pain in chronic Achilles tendinopathy3). To achieve this, bee venom pharmacopuncture, which is known for its potent anti-inflammatory effects, was used. Bee venom has been reported to exert its anti-inflammatory action by modulating the NF-kB and MAPK signaling pathways7).
In stage 2, the treatment target was MPS caused by the hypertonicity of the gastrocnemius and soleus muscles. In chronic Achilles tendinopathy, shortening and increased tension of these muscles exert continuous tensile stress at their calcaneal insertion, contributing to pain as an additional major factor11). To address this, hydrodissection was performed between the fascial planes of the gastrocnemius and soleus, and PDRN, known for its regenerative properties, was administered to promote healing of the damaged soft tissue. Unlike the pathological neovascularization targeted in Stage 3, the angiogenic effects of PDRN in this stage are intended to support the regeneration of normal microvascular networks within the fascia13).
The objective of stage 3 is to suppress the neurogenic inflammation induced by neovascularization and the accompanying ingrowth of sensory nerve fibers6). To achieve this, HVI using a placental pharmacopuncture solution was administered to mechanically disrupt the intralesional neovessels and hydrorelease the sensitized sensory nerves. Placental pharmacopuncture involves various growth factors, including VEGF, FGF, and EGF, which simultaneously promote tissue repair14).
Stage 4 targeted the enthesis of the Achilles tendon with the aim of promoting tissue regeneration through enhanced local blood flow and facilitating collagen remodeling in the damaged tendon matrix. HFEA is used to achieve this. This technique delivers electrical stimulation via acupuncture needles to induce a controlled local inflammatory response, thereby activating the healing cascade. Although no injectable solution was used in this stage, 27-gauge disposable injection needles were chosen over traditional acupuncture needles to enhance procedural stability and precision. Injection needles offer greater stiffness and improved tactile control during ultrasound-guided insertion into deep structures such as the enthesis, thereby minimizing needle deflection and ensuring accurate targeting for effective HFEA delivery. Recently, this modality has been reported to be effective in the management of various musculoskeletal disorders18).
This four-stage intervention is not intended to be applied uniformly to all cases of chronic Achilles tendinopathy. Rather, it should be tailored to each patient based on individual pathophysiological characteristics and ultrasound findings. For instance, patients without clinical or sonographic evidence of paratenonitis may not require Stage 1 treatment, while those without myofascial hypertonicity may not benefit from Stage 2. The choice of which stages to apply—and in what sequence—should be guided by comprehensive clinical evaluation and diagnostic imaging. Further research is warranted to establish standardized inclusion criteria and stage-specific indications.
In this case, the patient was followed up without additional intervention after completing the four-stage acupuncture treatment. At the two-month follow-up, her FAOS score showed further improvement compared with the score at the final treatment session. This outcome may be associated with the biological mechanism underlying stage 4 of the intervention, namely that periosteal pecking technique and HFEA induce controlled microinflammation within the Achilles tendon, which subsequently triggers a proliferative healing phase that unfolds over several months20). These findings suggest that the therapeutic effects of the treatment may persist and continue to improve even after the cessation of treatment. This highlights a key strength of the approach: its potential to initiate a biologically driven regenerative process with sustained clinical benefits.
This study had several limitations. Notably, ultrasound imaging before and after treatment did not reveal significant changes in the calcification thickness of the Achilles tendon. However, color Doppler examination revealed a clear reduction in neovascularization at the lesion site, which may indicate a favorable therapeutic response from a pathophysiological perspective. Marked improvements in pain and function were objectively confirmed using the FAOS.
Chronic Achilles tendinopathy is characterized by histopathological changes including collagen degeneration, fibrosis, and reduced vascularity. Therefore, anatomical abnormalities may persist even after treatment. The evaluation of treatment efficacy in this condition should prioritize symptom relief and functional improvement over anatomical normalization21). Previous studies have consistently shown a poor correlation between imaging findings and the severity of clinical symptoms of chronic Achilles tendinopathy21).
Conservative therapy for Achilles tendinopathy is generally recommended for 3–6 months22). Moreover, when calcific lesions are present, treatment response tends to be poorer, and recovery time has been reported to be more than twice as long3). Despite these challenges, the patient demonstrated meaningful improvements in both symptoms and function after approximately seven weeks of treatment. Furthermore, the therapeutic effects were maintained at the two-month follow-up after the final session. These findings suggest that the proposed treatment approach offers a nonsurgical approach with the potential to achieve clinically significant outcomes within a shorter timeframe than conventional conservative therapies.
Future studies are warranted to evaluate the applicability and reproducibility of this four-stage ultrasound-guided acupuncture strategy in prospective clinical trials. In particular, multicenter studies involving larger sample sizes across diverse age groups and occupational backgrounds are needed to assess the generalizability of the treatment effects. Long-term follow-up investigations should also be conducted to determine recurrence rates and the sustainability of functional improvements. Additionally, studies aimed at identifying clinical or imaging -based predictors of treatment responses would provide valuable insights. Given the promising results observed in this case, the proposed intervention holds potential as a novel nonsurgical treatment option for chronic Achilles tendinopathy; however, further research is needed to strengthen the level of evidence supporting its clinical use.
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