Bunion, which is also known as the hallux valgus, refers to a constellation of symptoms including soft tissue swelling over the first metatarsophalangeal (MTP) joint associated with abnormal angulation of the joint that results in a prominent first metatarsal head (Fig. 174.1). Ultimately, the first MTP joint may sublux, and the overlapping of the first and second toes worsens resulting in a painful condition known as the hallux valgus deformity (Fig. 174.2). Frequently, an inflamed adventitious bursa may coexist with the bunion, further exacerbating the pain and cosmetic deformity (Fig. 174.3). Occurring more commonly in women, bunion is most commonly the result of wearing shoes with too tight of toe box, with the wearing of high-heeled shoes exacerbating the problem (Fig. 174.4).

The majority of patients who present with bunion present with the complaint of pain that is localized to the affected first MTP joint and the inability to get shoes to fit. Walking makes the pain worse, with rest and heat providing some relief. The pain is constant and is characterized as aching and may interfere with sleep. Some patients complain of a grating or popping sensation with use of the joint, and crepitus may be present on physical examination. In addition to the just-mentioned pain, patients who suffer with bunions develop the characteristic hallux valgus deformity, which consists of a prominent first metatarsal head and improper angulation of the joint, with overlapping first and second toes.

Functional disability often accompanies the pain of the hallux valgus joint. Patients will often notice increasing difficulty in performing their activities of daily living and tasks that require standing, walking, or weight bearing. If the pathologic process responsible for pain of hallux valgus is not adequately treated, the patient’s functional disability may worsen, and muscle wasting and ultimately a frozen first MTP joint may occur.

Plain radiographs are indicated in all patients who present with pain of the hallux valgus (Fig. 174.5). Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging or ultrasound of the hallux valgus joint is indicated if fracture, effusion, tendinopathy, crystal arthropathy, joint mice, synovitis, foreign body, bursitis, or ligamentous injury is suspected (Fig. 174.6).

The MTP joints are condyloid joints characterized by the articulation of the rounded articular surfaces of the metatarsal heads into the shallow concavities of the articular surfaces of the proximal end of the first phalanges (Fig. 174.7). Each joint is lined with synovium, and the ample synovial space allows for intra-articular placement of needles for injection and aspiration. The MTP joints have a dense joint capsule and strong plantar and collateral ligaments, although fracture and subluxation may still occur. The MTP joints are also susceptible to overuse and misuse injuries with resultant inflammation and arthritis.

The benefits, risks, and alternative treatments are explained to the patient, and informed consent is obtained. The patient is then placed in the supine position with the knee flexed so that the plantar surface of the affected foot rests comfortably on the examination table (Fig. 174.8). With the patient in the above position, the dorsal surface of the MTP joint of the affected toe is identified by palpation (Fig. 174.9). A high-frequency small linear ultrasound transducer is placed in a longitudinal position over the MTP joint of the affected toe, and an ultrasound survey scan is taken (Figs. 174.10 and 174.11). The hypoechoic joint space is identified between the head of the metatarsal and the base of the proximal phalanges. When the joint space is identified, the skin overlying the area beneath the ultrasound transducer as well as the skin covering the lateral portion of the joint is then prepped with antiseptic solution. A sterile syringe containing 1.0 mL of 0.25% preservative-free bupivacaine and 40 mg of methylprednisolone is attached to a 1½-inch, 25-gauge needle using strict aseptic technique. The needle is placed through the skin just below the center of the longitudinally placed transducer and is then advanced using


an out-of-plane approach with the needle trajectory adjusted under real-time ultrasound guidance so that the needle tip ultimately rests within the MTP joint space (Fig. 174.12). When the tip of needle is thought to be in satisfactory position, after careful gentle aspiration, a small amount of local anesthetic and steroid is injected under real-time ultrasound guidance to confirm that the needle tip is in the proper position (Fig. 174.13). After proper needle tip placement is confirmed, the remainder of the contents of the syringe are slowly injected. There should be minimal resistance to injection.