Acupotomy to Treat Inversion of the Second Toe Combined with Eversion of the First Metatarsophalangeal Toe: A Case Report

Introduction

Hallux valgus (HV) is a common foot deformity characterized by the lateral deviation of the first metatarsophalangeal joint (MJ) and the medial protrusion of the first metatarsal head. It is often accompanied by pain, foot dysfunction, and secondary lesions [1]. According to epidemiological studies, the prevalence of HV can reach 23–35%, and it tends to increase with age and the wearing of certain types of shoes. In severe cases, it can lead to changes in foot biomechanics and difficulties with walking, significantly impacting the quality of life for patients [2]. Recent research [3] has identified foot mechanical imbalance, soft tissue relaxation, and joint stability as important factors in the development of HV. Specifically, abnormal tension in the plantar fascia and uneven mechanical distribution in the MJ are key contributors to the progression of the disease [4].

In Europe and the United States, the treatment of HV adheres to the principle of evidence-based, stepwise management, with personalized regimens formulated according to the severity of the deformity, measured by the hallux valgus angle (HVA), and individual patient conditions. For mild to moderate HV (HVA <20°), non-surgical treatment is the first choice, including the use of orthopedic braces (such as night splints and toe separators), physical therapy (plantar muscle training and gait correction), and non-steroidal anti-inflammatory drugs to relieve symptoms [5]. Studies have shown that these conservative treatment methods can effectively delay the progression of the deformity and improve function [6]. For patients with ineffective conservative treatment or moderate to severe deformity (HVA >20°), surgical treatment should be considered [7]. Commonly used surgical procedures in European and American countries include soft tissue balancing surgeries (eg, the McBride procedure), osteotomy for orthopedic correction (eg, the Chevron, Scarf, and Lapidus procedures), and arthrodesis. Among these, minimally invasive osteotomy has been widely applied in recent years due to its characteristics of minimal trauma and rapid recovery [8]. It is worth noting that European and American treatment guidelines specifically emphasize the need for accurate assessment of the severity of the deformity through imaging examinations before surgery and the implementation of systematic rehabilitation training after surgery to achieve optimal therapeutic effects [9]. However, surgical treatment still has limitations, such as relatively high trauma and long recovery period [10]. In contrast, the small needle-knife technique described in the present study provides a more minimally invasive and cost-effective treatment option for patients with mild to moderate HV.

As a treatment method of integrated traditional Chinese and Western medicine, acupotomy therapy has shown unique advantages in treating HV. Its main mechanism of action is to release the contracted soft tissue in the foot, restore the mechanical balance of the MJ, and improve local blood circulation, so as to relieve pain and correct deformity. Based on the central role of foot mechanical imbalance in the pathogenesis of HV, this article elaborates on the scientific basis for acupotomy therapy in regulating foot mechanical balance and restoring joint stability, and discusses its optimization scheme in the treatment of HV, aiming to provide a safer and more effective treatment option for patients with HV.

Case Report

This case report was written in accordance with the CAse REport (CARE) guidelines [11].

A 52-year-old woman first visited our clinic on October 22, 2024. The chief complaint was “varus of the second toe of the left foot with pain in the first MJ for more than 5 years, which worsened in the past month”. Five years ago, the patient had gradually developed the varus deformity and had been experiencing intermittent pain in the first MJ, especially after long walks. Despite using topical medications and toe splints intermittently, the symptoms continued to recur. One month previous to her visit to our clinic, the patient experienced prolonged exertion which resulted in an increase in the angle of the second toe varus and worsening pain in the first MJ. As a result, she sought treatment at our hospital’s outpatient clinic. Pain was measured in the clinic using the visual analogue scale (VAS).

The patient presented with several symptoms. Video 1 shows the varus deformity of the second toe of the left foot, with a second toe varus angle (TVA) of 25°, mild valgus of the first MJ (HVA 12°), and obvious tenderness (VAS score of 6 points). Additionally, the patient had a flexion contracture of the proximal interphalangeal joint of the second toe and callus formation under the second metatarsal head of the foot, and she had experienced increased pain while walking, without any numbness in the lower limbs or intermittent claudication. Upon physical examination, it was observed that the second toe of the left foot had a varus deformity with a TVA of 25°. Additionally, there was a mild valgus of the first MJ with an HVA of 12°. The dorsal skin folds of the second metatarsophalangeal joint were deeper than normal, and there was a flexion contracture of the proximal interphalangeal joint with limited passive extension. On the medial side of the first metatarsophalangeal joint, there was mild redness and swelling, along with a slightly increased skin temperature and positive tenderness. The range of motion for dorsiflexion and plantarflexion, as well as the muscle strength and sensation in both feet, were normal. The peripheral blood supply was also normal, and there were no pathological signs present.

X-ray showed subluxation of the second MJ of the left foot, valgus of the first MJ (HVA 12°), hyperostosis on the dorsal side of the second metatarsal head, and narrowing of the joint space. A mild osteophyte was formed on the medial side of the first metatarsal head. The diagnosis was varus deformity of the left second toe combined with valgus of the first toe. The treatment plan was: utilization of acupotomy to release contracted tendons and soft tissue adhesions, while manipulation was used to correct imbalances of the force line. The needle-knife used was a disposable 0.8*65 mm Hanzhang needle-knife. After communication with the patient, the patient accepted the treatment plan and signed a written informed consent.

The preparation before the procedure was as follows: First, the patient was placed in the supine position with the left lower limb naturally extended and the affected foot was placed on a soft pad to fully expose the treatment area. The surgeon wore a disposable medical cap, surgical mask, and sterile gloves. Iodophor was used to disinfect the foot skin, with antisepsis done 3 times, covering the dorsum of the foot, the sole, and the ankle joint. The key operation points were marked by palpation combined with imaging localization. Anesthesia was administered at specific points (see Table 1), including the medial part of the first MJ (the site of the medial joint capsule swelling, the attachment point of the medial collateral ligament, and the protruding part of the osteophyte); attachment points of the adductor pollicis and abductor pollicis tendons (the lateral adductor pollicis insertion point on the first metatarsal head and the medial abductor pollicis insertion point); the flexor sheath of the second toe (at the thickening area of the sheath of the palmar flexor tendon of the proximal interphalangeal joint); the medial capsule of the second MJ (in the medial tension area); and the intermetatarsal ligament (at the contracture area of the second and third intermetatarsal head ligament).

The procedure was conducted as seen in Video 2: The surgeon fixed the hallux in the mild varus position with his left hand and held a Hanzhang acupotome (0.8×65 mm) in his right hand. The knife edge was parallel to the fiber direction of the medial collateral ligament. The needle was inserted vertically into the skin at the marking point (the medial side of the first MJ), and was slowly used to penetrate to the bone surface (the depth was about 0.5–1.2 cm). First, the surgeon made 3–5 longitudinal cuts to release the thickened medial capsule and ligaments. Next, the soft tissue adhesion on the osteophyte surface was removed by lifting and shoveling until a sense of loosening was felt. Second, the surgeon focused on releasing the attachment point of the adductor pollicis and abductor pollicis tendons. The needle knife was inserted from the lateral edge of the first metatarsal head and inserted to the aponeurosis layer at the lateral adductor pollicis insertion point. The knife edge line was parallel to the longitudinal axis of the metatarsal bone. The contracture was then released by 2–3 cuts laterally. Third, the needle knife was inserted obliquely into the tendon-bone junction at the medial abductor pollicis insertion point, along the medial edge of the first metatarsal head. This was followed by longitudinal dredging and sectoral stripping to stimulate the recovery of tendon tension. To release the adhesion of the flexor sheath of the second toe, the needle knife was inserted from the palmar side of the proximal interphalangeal joint and penetrated to the tendon sheath layer. The knife edge was kept parallel to the flexor tendon. The adhesion of the tendon sheath was relieved by making 3 longitudinal cuts. The needle knife was then lifted and inserted further until the sliding sensation of the tendon was restored. After that, to treat the medial capsule of the second MJ, the needle knife was inserted obliquely into the capsule from the medial edge of the second metatarsal head, with the knife edge line consistent with the longitudinal axis of the metatarsal bone. The medial contracting fibers were released through a combination of longitudinal dredging and sector-shaped dissection. Finally, to release the intermetatarsal ligament, the needle knife was inserted from the dorsal side of the second and third metatarsal heads, parallel to the transverse arch of the foot, into the superficial layer of the intermetatarsal ligament, and the lateral compression was relieved by swinging and stripping laterally twice.

After the operation, a manual reduction was performed. This involved using a hand to stabilize the second metatarsal bone while the other hand grasped the distal end of the second toe. The toe was pulled and abducted to correct the varus deformity, and then a split-toe orthosis was used to fix the second toe in a neutral position. After that, the thumb was pressed against the lateral side of the first metatarsal head. The patient was then instructed to actively adduct the hallux against resistance for 10 seconds at a time. This procedure was repeated for 5 sets, to strengthen the contraction function of the abductor pollicis muscle. After treatment, there was an obvious therapeutic effect immediately (Figure 1). The TVA had decreased by ≥15°, and the extension range of passive motion increased by >10°. There was also a reduction of ≥5° in the HVA.

Postoperative management included pressing with sterile gauze to stop bleeding after withdrawal of the needle knife, covering the incision with a Band-aid, and applying the affected area on ice for 15 minutes to reduce edema. Weight-bearing walking was avoided for 24 hours after surgery, and the incision was kept dry for 3 days. The patient was instructed to wear a split-toe orthosis, which maintained the force line of the second toe. The patient was instructed to perform passive extension of the second toe and adduction of the first toe in a daily training routine (10 minutes, 3 times/day), and to avoid wearing narrow-toed shoes.

At the 2-month follow-up, there were significant improvements in the patient’s condition. The TVA had decreased by ≥18°, the passive extension range of motion increased by >13°, the first MJ HVA had decreased by ≥5°, her VAS score decreased to 3 points, and her Foot and Ankle Ability Measure (FAAM) increased by >65%.

Discussion

HV is a common foot deformity, and its pathological mechanism involves complex biomechanical imbalance and soft tissue degeneration. According to modern medicine, the core pathological changes are varus of the first metatarsal and HV, often accompanied by thickening of the medial joint capsule, contracture of the adductor pollicis muscle, and abnormal tension of the plantar fascia. Long-term abnormal stress can induce osteophyte hyperplasia and synovitis of the metatarsal head, which further aggravates the pressure and pain of the joint cavity [12]. Currently, the main clinical treatment options are non-surgical interventions, such as orthopedic braces, anti-inflammatory drugs, and physical therapy. However, these methods have limitations, including a high risk of recurrence and an inability to correct deep mechanical abnormalities. While surgery can correct bony deformities, it also carries the risks of major trauma, a long recovery period, and postoperative joint stiffness. Therefore, it is of great clinical value to explore a treatment plan that takes into account both minimally invasive and biomechanical reconstruction.

Based on the theories of off-position sinews and joint semidislocation in Chinese medicine, the essence of HV lies in the vicious cycle of muscle and collateral spasm and bone position disorder. In this case, the patient suffered from long-term strain combined with cold and dampness, resulting in qi stagnation of the 3 Yin foot meridians, and qi and blood stasis in the MJ, forming the syndrome of “water stagnation” and “phlegm and blood stasis”. Through the compound effect of “probing the acupoint with acupuncture and unknotting the knot with knife”, acupotome treatment can accurately release the medial joint capsule, the contracture band of the adductor pollex muscle, and the adhesions around the osteophyte, and directly cut off the pathological tension chain, which is in line with the treatment principle of “eliminating prolonged stagnation” in Miraculous Pivot: Nine Needles and Twelve Yuan. The release effect of the needle-knife can reduce the stress on the medial longitudinal arch and improve the hallux varus and valgus angles [13]. The combination of postoperative dynamic traction and muscle strength training can be used to successfully reconstruct the co-contraction mode of the abductor pollicis and adductor pollicis by activating proprioceptive input, and break the pathological closed loop of “imbalance of force line to aggravation of deformity”.

Globally, research into treatment strategies for HV have developed into a relatively systematic research system. In European and American countries, studies are primarily focused in 2 areas: surgical correction and biomechanical analysis [14]. In surgical treatment, osteotomy procedures such as Chevron, Scarf, and Lapidus are mainstream, emphasizing precise orthopedics and functional recovery [15]. In recent years, minimally invasive surgery has been rapidly adopted due to its minimal trauma and quick recovery [16]. For non-surgical interventions, although orthopedic braces and physical therapy are widely used, their long-term efficacy remains limited [17]. Biomechanical studies, through gait analysis, have revealed associations between abnormal plantar pressure distribution and the progression of deformities [18].

In China, HV treatment is characterized by the integration of traditional Chinese and Western medicine. The small needle-knife technique has shown efficacy in improving mild to moderate HV by releasing the medial joint capsule and tendon insertion points, but research on complex deformities (eg, combined second toe varus) remains scarce. Traditional Chinese orthopedic manipulation has certain therapeutic effects but suffers from insufficient long-term stability [19]. Additionally, while domestic scholars have made progress in modifying Western osteotomy procedures, challenges such as postoperative joint stiffness persist [20].

Against this backdrop, the present study achieves 3 key breakthroughs: First, it is the first to systematically explore the feasibility of using small needle-knife therapy for the complex deformity of HV combined with second toe varus. Second, it innovatively proposes a multi-target release strategy, which addresses key structures such as intermetatarsal ligaments and flexor tendon sheaths simultaneously, better aligning with the biomechanical correction needs for complex deformities. Finally, it adopts an objective evaluation system combining imaging and functional scores (eg, FAAM), providing empirical support for the short-term efficacy of small needle-knife therapy. These innovations not only fill the research gap in treating specific HV subtypes but also offer new insights into the integration of traditional Chinese and Western medicine for foot deformities.

In the clinical application of acupotomology, it is crucial to pay attention to the following issues: 1. The principle of “bone surface as the boundary, releasing layer by layer” must be strictly adhered to in order to prevent any damage to the dorsalis pedis artery and/or the branches of the deep peroneal nerve. 2. In cases of severe deformity (HVA >40°) or when combined with severe osteoarthritis, it is recommended to use combined osteotomy to enhance the effectiveness of treatment. 3. The postoperative rehabilitation system is not yet standardized; therefore it is necessary to develop a personalized training program that takes into account the biomechanical evaluation of the foot and ankle. In the future, it will be important to conduct multi-center randomized clinical trials to clarify and classify the indications for acupotomy treatment. Additionally, the design of the cutting path should be optimized with the assistance of finite element modeling.

Conclusions

In conclusion, acupotomology provides an integrated solution based on “minimally invasive mechanical correction and functional remodeling” for hallux varus and valgus through precise anatomical intervention and overall biomechanical regulation. Its therapeutic mechanism integrates modern biological theory with traditional Chinese medicine’s theory of meridian tendons. This reflects the scientific innovation that can result when combining integrated traditional Chinese and Western medicine to develop new treatment strategies. Further standardization of the operation and improvement of the efficacy evaluation system will promote the wider application of this technique in the field of foot and ankle diseases.