Hallux Valgus

　　1.Genetic The occurrence of hallux valgus deformity is related to congenital factors, about half of the cases have genetic factors. Lake believes that the inward deviation of the first metatarsal bone is the main cause of the deformity. Clinically, many patients have the first cuneiform bone in the shape of a narrow wedge on the inside, causing the metatarsophalangeal joint to tilt inward. However, in the author's group of 76 feet with hallux valgus, only 9 feet have the first metatarsal bone inwards exceeding 12°. According to Carr's standard, the angle between the first and second metatarsal bones is 9°, and only a small part exceeds this standard, indicating that metatarsal varus is not congenital. Among these 76 feet, 11 feet had a reduction of 2° to 4° in the angle between the first and second metatarsal bones after McBride surgery, which is obviously due to the reduction in the bowstring action of the extensor and flexor muscles of the big toe after the correction of hallux valgus, as well as the influence of the adductor muscle moving to the first metatarsal bone. At the same time, after hallux valgus, the bowstring action of the muscles must produce a force to push the metatarsal bone inwards.

　　2.Wearing high-heeled pointed shoes It is one of the main factors for the formation of hallux valgus. The front of the pointed toe shoe is triangular, when standing on high heels, the front part of the foot is pressed into a narrow triangular area, the hard shoe surface forces the big toe to abduct and slightly rotate outward, the little toe to adduct and slightly rotate inward, and the middle three toes to flex the proximal interphalangeal joints strongly, and the metatarsophalangeal joints and distal interphalangeal joints to overextend.

　　3.Various inflammations Especially rheumatoid arthritis, often due to joint destruction forming an outward semi-dislocation, presenting as hallux valgus deformity.

　　1. As the hallux valgus becomes more severe, the first metatarsal bone inwards also becomes more severe, the pressure and friction at the first metatarsal head increases, locally the bursa thickens, and osteophytes proliferate to form a large bone拐. The front foot becomes significantly wider, making it difficult for these people to choose a pair of suitable and beautiful shoes. With the arrival of the hot summer, they also cannot wear sandals because they feel that their feet are not beautiful or even ugly.

　　2. Due to long-term friction, the soft tissue on the inner side of the first metatarsal bone thickens and swells, locally causing aseptic inflammation and forming bursitis (commonly known as 'hallux bursitis' in clinical practice), and severe pain, which affects walking.

　　3. Due to the first toe of the foot being laterally deviated, the second toe is lifted upwards, and the other toes are compressed from the outer side of the shoe, causing deformities in the second to fourth toes resembling chicken claws. This leads to friction on the dorsal side of the toes, which can form corns and calluses, most commonly seen on the dorsal side of the second and fourth toes; at the same time, due to toe deformity, the metatarsal heads are compressed and collapse, forming corns on the sole of the foot, which is most common at the base of the second toe. Corns and calluses can cause severe pain and recurrent attacks, seriously affecting the quality of life and work.

　　4. Due to the widening of the forefoot, the collapse of the transverse arch, the foot will be slightly outwardly flipped when walking, which will change the load-bearing surface of the ankle joint, causing traumatic inflammation of the ankle joint, pain, and even affecting the knee joint, hip joint, and even the waist.

　　5. Due to the widening of the forefoot, the collapse of the transverse arch, the reduction of the shock absorption of the foot, and the decrease of the foot's jumping ability, these people's ability to move is seriously affected. In short, hallux valgus is not only a pathological condition itself but also can produce some complications that affect people's lives.

　　1.Clinical manifestations Common in adults, those with genetic factors may occur in youth, and in old age, due to the weakening of the internal retraction force of the foot, hallux valgus often worsens. Women are more common than men.

　　The most common symptoms of hallux valgus are bursitis and pain. The long axis of the normal big toe forms an angle with the long axis of the first metatarsal, and the shape measurement is 15° to 25°, known as the physiological hallux valgus angle. There is no fixed standard for how much tilting is considered hallux valgus. Clinically, only when the hallux valgus exceeds 25°, squeezing the second toe, and there is bursitis pain at the first metatarsal head, can it be diagnosed as hallux valgus. Pain is the main symptom and also the main basis for treatment. The pain mainly comes from the inside of the first metatarsal head, and the pain worsens when walking. Some patients may have callus pain on the plantar surface of the second and third metatarsals. It is noteworthy that deformity and pain are not proportional, some deformities are very obvious but not painful, and the pain of hammer toe and callus of the second and third toes is also an important sign.

　　2.Staging According to the clinical manifestations, X-ray changes, and treatment options, hallux valgus is divided into 3 stages.

　　(1) Early stage (pre-subluxation stage): The big toe has a mild valgus deformity, the bursitis is mild, the pain is not severe, and X-ray film shows the big toe metatarsophalangeal joint is semi-dislocated outwardly, without hammer toe. At this stage, it can be corrected manually and non-surgical treatment can be used.

　　(2) Middle stage (subluxation stage): The big toe has a significant valgus deformity, the pain of bursitis is severe, and X-ray film shows the base of the proximal phalanx of the big toe is semi-dislocated laterally from the metatarsal head. Because the big toe pushes the second toe outward, this toe may develop a hammer toe deformity, leading to the depression of the metatarsal head below, and the occurrence of callus at the head of the metatarsal. At this stage, although the position can be corrected manually, it cannot be consolidated. For women aged 30 to 50, the valgus angle of the metatarsophalangeal joint is between 15° to 25°, and the metatarsal angle between the metatarsals.

　　(3) Late stage (osteoarthritis stage): In addition to the pain of bursitis, the metatarsophalangeal joint is swollen and painful, and X-ray film shows osteoarthritis in the metatarsophalangeal joint. Surgical treatment is suitable for combined bone and soft tissue surgery at this stage.

　　Hallux valgus exceeds the normal angle, X-ray film shows semi-dislocation of the first metatarsophalangeal joint and内侧bursitis of the first metatarsal bone. The first metatarsal is in varus, hammer toe and callus, which are not necessarily present in every case. In the early stage, the big toe can be passively moved to a normal position, but in the later stage, due to the contraction of the joint capsule and muscle, it cannot be passively moved back to the normal position. At this stage, the occurrence of hallux metatarsophalangeal osteoarthritis has entered the late stage.

　　1. Do not ignore foot pain, as it is not caused by mere fatigue. Once foot pain occurs, seek medical advice.

　　2. Regularly observe your feet and pay attention to changes in the color and temperature of your foot skin. If you find thickening and discoloration of the toenails, this may indicate an infection of athlete's foot.

　　3. Wash your feet often, especially between the toes, and make sure to dry them thoroughly.

　　4. Trim the toenails straight and not too deep, be careful when trimming the edges and corners of the toenails. Improper trimming can lead to ingrown toenails. Especially for diabetic patients or those with poor circulatory and cardiac function, once ingrown toenails occur, they can lead to incurable infections.

　　5. Choose a pair of appropriate shoes, and it is recommended to buy new shoes in the afternoon when the feet are at their largest due to swelling.

　　6. It is recommended to choose different specialized shoes for different types of exercise.

　　7. Generally, do not wear the same pair of shoes continuously for more than two days.

　　8. Avoid walking barefoot to prevent injury or infection. It is recommended to apply sunscreen to the feet like other parts of the body when walking on the beach or wearing sandals in summer.

　　9. Do not self-treat any foot problems to avoid infection or more serious issues.

　　10. If you are a diabetic patient, perform a foot examination at least once a year.

　　The above are common measures to prevent bunions.

　　X-ray manifestations include the lateral subluxation of the first metatarsophalangeal joint, the displacement of the big toe towards the midline, the prominence and ossification of the medial aspect of the first metatarsal head, and the lateral displacement of the sesamoid bones. The first metatarsal is varus, and the angle between the first and second metatarsals is greater than 9°. In the late stage, the first metatarsophalangeal joint undergoes degenerative changes, the joint space narrows, and there are osteophytes around the joint.

　　Bunion is a disease. Although in the early stage, it does not bring too much discomfort to people except for the unattractive appearance, difficulty in choosing shoes, and easy damage to the shoe shape. However, as age increases, the severity of the bunion deformity increases, leading to many serious complications such as bursitis, hammertoes, corns, and calluses; these complications not only affect foot function but also cause pain, seriously affecting daily life and work. Therefore, it is recommended to prevent and treat bunions as soon as possible when bunion deformity is found. In this way, not only can the progression of bunions be delayed, but also the occurrence of some complications can be effectively prevented. The specific preventive and treatment measures are as follows:

　　(1)Choose a pair of appropriate shoes, such as those with not too high heels and a wider toe box. Allow the toes to have some space inside without feeling any pressure, especially avoid wearing pointed and narrow high heels.

　　(2)Engage in barefoot exercises to strengthen the foot sole muscle strength and delay the progression of bunions.

　　(3)Daily, using your fingers to push the big toe inward can also effectively prevent the progression of bunions.

　　(4)Wearing some orthopedic devices, such as bunion splints (including daytime and nighttime splints) for a long time can have a certain therapeutic effect on bunions.

　　(5) When the above conservative treatment cannot effectively correct the deformity, surgical treatment should be adopted, which is the most effective treatment method. Correction of deformity by surgical method is effective, and after surgery, not only can you choose the shoes you want to wear, but you can also return to normal work, especially for those with special professions, such as dancers, who can resume a normal dance career.

　　1.Non-surgical treatment For early lesions with mild pain, non-surgical treatment can be adopted, including wearing shoes with a wide forepart and a heel height not exceeding 2.5 cm, massage, moving the great toe towards the medial side of the foot, walking barefoot on sand and soil, exercising the foot muscles, hot compress, rest, etc. Exercise for correcting hallux valgus also has certain efficacy, that is, to wrap a rubber band on both first toes and perform opposite traction movements, 2 times/day, each time 5-10 minutes (Figure 2).

　　It is also an effective method to reduce the pressure and friction on the bony prominence, such as placing a soft pad around the bony prominence. If the pain is localized to the bursitis or metatarsophalangeal joint, puncture and drainage can be performed at the painful area, and local injection of corticosteroids.

　　2.Surgical treatment The main purpose of surgical treatment is to relieve pain and correct deformities, suitable for patients in the middle and late stages. Some hallux valgus deformities are very severe, but they are not painful, and surgical treatment is not needed.

　　More than 200 surgical methods have been reported, which can be summarized into 5 categories: ①Soft tissue surgery: mainly to cut off the insertion of the adductor hallucis at the proximal phalanx, and relocate it to the lateral side of the first metatarsal head, represented by the McBride operation; ②Osteotomy: resect part of the bone to relax the contracted soft tissue and relieve symptoms, commonly used are Mayo surgery and Keller surgery; ③Osteotomy for correcting the varus deformity of the first metatarsal, or to perform soft tissue surgery and/or osteotomy at the same time; ④Arthrodesis of the first metatarsophalangeal joint; ⑤Mini-incision surgery.

　　The main operations included in various surgeries are: ①Correct the hallux valgus deformity of the proximal phalanx of the great toe; ②Excise the osteophyte of the first metatarsal head, and excise the synovium if necessary; ③Correct the varus deformity of the first metatarsal; ④Correct the tense extensor tendons of the great toe; ⑤Correct other deformities of the forefoot, such as hammertoes, and introduce several commonly used surgical methods:

　　(1) Excision of osteophyte of the first metatarsal head (Mayo operation):

　　①Indications: The bursitis of the great toe is obvious, but the intermetatarsal angle and hallux valgus deformity are not severe, and the pain is localized to the medial side of the first metatarsal head in young patients with bursitis.

　　②Key points of the operation:

　　A. An oblique incision is made on the back of the first metatarsophalangeal joint along the medial side of the extensor tendons of the great toe, avoiding the area compressed and rubbed by the shoe upper. The lateral aspect of the great toe dorsal cutaneous nerve and the accompanying veins are pulled laterally, the joint capsule is incised arched along the dorsal margin of the bursitis, the synovial joint capsule flap is flipped distally, exposing the marginal osteophytes of the metatarsal head, allowing the great toe to sublux laterally, resected proximally from the articular cartilage groove on the medial side of the metatarsal head, the osteophytes on the medial side of the metatarsal head are smoothed, the synovial joint capsule fascia flap is tightened proximally, making the long extensor muscle of the great toe parallel to the long axis of the metatarsal shaft, correcting the hallux valgus, and sutured to the proximal periosteum, but do not suture inwards.

　　B. Apply pressure dressing, fix the metatarsophalangeal joint at an inversion of 5°, and start joint movement of the affected toe joint after 3 weeks postoperatively. The Mayo surgery alone, as it only removes one of the many pathological changes of hallux valgus, cannot consolidate the effect in some cases with complex pathological changes, is prone to recurrence, and should be used with caution.

　　Lu Yupu and others adopted the technique of cutting the adductor pollicis, excising the medial metatarsal head bursa and bone spur and overlapping the tenodesis flap of the medial joint capsule for patients with mild hallux valgus, that is, adductor pollicis sectioning plus Mayo surgery. The treatment of more than 50 cases achieved good results.

　　(2)Modified McBride surgery:

　　①Indications: Young and middle-aged patients with mild deformity, shorter first metatarsal, and hallux valgus without metatarsophalangeal joint osteoarthritis, this operation includes: the adductor pollicis is transferred from the insertion point on the proximal phalanx to the lateral aspect of the first metatarsal head, the lateral joint capsule is incised, the bursitis bone spur is excised, and the medial joint capsule is tightened.

　　②Surgical points: A. A 5cm longitudinal incision is made on the dorsal side between the first and second toes, extending towards the proximal side to the metatarsal heads, the dorsal peroneal nerve and vein of the big toe are pulled towards the tibia side, and the deep dissection is performed along the lateral aspect of the metatarsophalangeal joint capsule, the transverse ligament of the metatarsus is cut, and the transverse and oblique heads of the adductor pollicis are cut from the base of the proximal phalanx and the lateral sesamoid bone, and they are separated bluntly towards the proximal side, and the ends are sutured with thick silk threads, leaving a long thread for reserve. The thick lateral joint capsule is incised along the joint line from the dorsal midline to the plantar side, allowing the big toe to move inward.

　　An arched incision convex to the dorsal aspect is made on the medial side, the operation is the same as the above Mayo surgery. A transverse hole is made at the neck of the first metatarsal, the tendons of the adductor pollicis with thick silk threads are pulled into the bone hole, and the metatarsal head is pushed outward and tied to fix it, thus converting the traction force of hallux valgus into the traction of the metatarsal head outward (midline). The skin is sutured, and pressure dressing is applied. The great toe is fixed in the corrected position with a plaster bandage postoperatively, and the cast is removed after 3 weeks for exercise, and it is allowed to wear shoes and walk.

　　For patients with a first and second metatarsal intermetatarsal angle greater than 10° accompanied by hallux valgus, to prevent recurrence of hallux valgus, simultaneous first metatarsal base osteotomy should be performed. The osteotomy method is determined by the length of the metatarsal; for those with normal metatarsal length, arc osteotomy is used; for those with shorter metatarsals, open wedge osteotomy is preferred, and for those with longer metatarsals, closed wedge osteotomy is preferred. Here, the open wedge osteotomy is illustrated. A straight incision is made near the middle of the proximal shaft of the first metatarsal, the periosteum is incised to expose the metatarsal cuneiform joint beyond 5mm, osteotomy is performed from inside to outside until the lateral cortical bone is broken, but the periosteum is retained. The metatarsal head is pressed outward to open the osteotomy site, and the medial protuberance of the cut metatarsal head is trimmed into a wedge shape and implanted to maintain the corrected position of the metatarsal osteotomy. The incision is sutured, and the cast is applied for 4 to 6 weeks postoperatively.

　　To maintain the transverse arch, postoperative emphasis should be placed on toe flexion exercises and the use of transverse arch insoles.

　　(3) Keller joint excision and reshaping surgery:

　　①Indications: Moderate to severe hallux valgus (30°-45°) with osteoarthritis, age 55-70 years, rigid great toe, and elderly patients with less activity who have hallux valgus, are among the most commonly used surgical procedures for treating hallux valgus. The Keller procedure includes three parts: soft tissue release, excision of the lateral process, and resection of the proximal phalanx. This operation can correct deformity and relieve pain in the great toe, but the great toe may be thick and weak with little power for several months to one year after surgery, and the range of motion of the metatarsophalangeal joint may also be smaller. The patient should be clearly explained before surgery.

　　②Key points of the operation:

　　A. An arched incision is made on the dorsal side of the first metatarsophalangeal joint, curving medially or straight, 4-5 cm in length, with钝性separation, and the most medial branch of the superficial peroneal nerve located near the distal end of the lateral process is protected. The joint capsule of the metatarsophalangeal joint and the periosteum near the proximal half of the proximal phalanx are incised, and the periosteum is separated medially and laterally until they meet on the plantar surface. Alternatively, an arched incision can be made on the dorsal side of the metatarsophalangeal joint, and the periosteum is incised and stripped, allowing the proximal phalanx to dislocate medially from the metatarsal head. The proximal third to half of the phalanx is resected, maintaining a 0.5-1 cm gap between the bone ends after surgery. The medial process of the metatarsal head is then excised at the coronal sulcus, with a width similar to the Mayo operation, but with the joint cartilage preserved. After thorough hemostasis with the tourniquet removed, the remaining periosteum and joint capsule are sutured with 2-0 or 3-0 absorbable suture. To maintain the gap after excision, Kirschner wires can be inserted into the phalanx and metatarsal head to support them. If the extensor tendons are tense, an extension procedure can be performed (Figure 4).

　　B. Postoperative compression bandaging. Starting from the third week, functional activities can be initiated. For patients with Kirschner wire fixation, adhesive strips can be used to traction the affected toe.

　　(4) Oblique interlocked osteotomy of the metatarsal neck:

　　①Indications: This operation mainly involves osteotomy, which can achieve good morphological and functional outcomes after surgery. It is suitable for patients with a longer first metatarsal bone without obvious hallux valgus arthritis and joint stiffness.

　　②Key points of the operation:

　　A. The incision is made on the medial side of the extensor tendons of the great toe, from the proximal phalanx to the middle of the metatarsal shaft, curving towards the dorsal side. After incising the skin, the terminal branches of the superficial peroneal nerve on the medial side should be protected. The bursa and periosteum are longitudinally incised along the incision direction, and the periosteum is separated circumferentially laterally at the neck of the metatarsal. The lateral process of the metatarsal head is removed. An oblique osteotomy is made from the lateral side of the metatarsal head towards the proximal tibial side, stopping near the attachment of the joint capsule. The joint capsule should not be separated from the metatarsal part to avoid ischemic necrosis of the metatarsal head. After osteotomy, the two bone ends are trimmed and pushed outwardly under traction, with the proximal and distal ends interlocking. Generally, the stability is good and internal fixation is not required. In the corrected position, the periosteum and joint capsule on the medial side are sutured overlyingly (Figure 5).

　　B.术后石膏固定4～5周，拆除固定后行功能锻炼。

　　(5)第1跖趾关节融合术：如选择病例正确，第1跖趾关节融合术是治疗拇外翻最适当术式之一。

　　①适应证：

　　A.畸形严重;拇外翻角>45°，伴拇趾严重旋前，趾间角超过20°，特别是在第2、3跖骨头下方存在痛性胼胝，且前足垫萎缩者。

　　B.拇外翻伴骨关节炎。

　　C.拇外翻复发。

　　D.肌力不平衡所致的拇外翻畸形;内侧关节炎全部结构破裂且不能充分修复的创伤后拇外翻。

　　②手术要点：第1跖趾关节融合术的手术方法依截骨的类型和固定种类不同而异，常用的有小钢板固定融合术、截锥融合术、多根螺纹克氏针融合术、球臼融合术。医师可根据病情与个人经验选定。

　　(6)小切口截骨术：小切口截骨术治疗拇外翻的方法在欧美被许多足外科医生所推荐，该方法专业技术要求高，但由于创伤小，不需内固定，病人可以早期下地活动，痛苦小，恢复快。对用大切口有丰富经验的临床医生可以选用。

　　手术可在局麻下进行，首先用小圆刀在拇趾近节趾骨近端内侧做约1cm切口，直达趾骨，骨膜剥离器从远端向近端在拇囊和内侧跖骨头之间分离关节囊，用磨钻磨去跖骨头内侧突，并用骨锉锉平跖骨头内侧。然后在第1跖骨头颈内侧做约O.5cm切口，直达跖骨，用削磨钻从远端向近端做一