Hallux valgus deformity, colloquially known as a bunion, is a result of medial deviation of the first metatarsal with a resultant increase in the intermetatarsal angle between the first and second metatarsals. In patients who have pain associated with this deformity that precludes normal activity or becomes a limiting problem, surgery is a reasonable option in an effort to correct the bony deformity and thereby decrease the related pain.

Hallux valgus is one of the most common foot deformities seen in orthopaedic clinical practice. This pathology can cause a cascade of events affecting the foot as well as more proximal joints in the lower extremity. It has been linked to foot pain, impaired gait patterns, poor balance, and falls in older adults. It is more common in females, and the incidence increases with age.

A full understanding of foot anatomy, kinesiology and biomechanics is pivotal when treating this patient population. An array of factors can influence the foot and have the potential to compound the deformity. Deficits in talocrural dorsiflexion, increased pronation of the foot, and narrow shoe wear are all factors to consider. Although less common in adolescents, it can be a cause of impairment related to structural defects that predispose to the condition.

An altered plantar pressure pattern is typically seen in bunion patients, with decreased loading of the hallux and increased loading under the second and third metatarsal heads. With surgical intervention and physical therapy, these plantar pressures can be restored close to normal values, and symptoms can be eliminated. Given the multifactorial nature of this problem, it is important for the therapist to assess and address these concerns in the postoperative patient.

In general, bunion operations, of which there are quite literally over a hundred variations, all essentially consist of either cutting bones (metatarsal, phalangeal osteotomies) or fusing joints (tarsometatarsal [TMT], metatarsophalangeal [MTP]) to straighten out the first ray.

Depending on what type of operation is performed, the postoperative protocol can vary significantly. In general, metatarsal osteotomies and phalangeal osteotomies require less time non–weight bearing (NWB) than fusion operations. For the purposes of this chapter, we will talk about one specific type of metatarsal osteotomy, the scarf osteotomy, for which postoperative rehabilitation can be generalized for all metatarsal osteotomies. In addition, we will review one specific type of fusion operation, the Lapidus procedure, or first TMT fusion. Both procedures are typically accompanied by a lateral release and a medial plication of the MTP joint. The lateral release, often called a modified McBride procedure, consists of the release of the tight lateral structures (the adductor hallucis tendon, lateral joint capsule, and transverse metatarsal ligament). This lateral release and medial plication allows for appropriate realignment of the proximal phalanx on the metatarsal head. It is important to note that although rehabilitation protocols are often generalized, there should be an open communication with the surgeon and therapist to customize each individual’s progressions based on age, comorbidities, surgical procedure, tissue quality, expectation, and physical fitness levels. We will not review rehabilitation after MTP fusion, which has a more limited role in bunion treatment.

In general, metatarsal osteotomies are done for less severe deformity, whereas first TMT fusions are done for severe deformity that may include looseness at the metatarsal-cuneiform joint. While the debate over which operation is more appropriate for different types of bunions has existed for many years and has been contentious at times, most would not argue that a Lapidus provides the greatest capacity to correct deformity and keeps the bones straight, whereas a metatarsal osteotomy makes the bone crooked to make it appear straight. However, metatarsal osteotomies typically heal more readily than a first TMT fusion; thus, they usually require NWB for about half the time or less than a Lapidus would, which is not an insignificant consideration.

From a rehabilitation perspective, concerns include regaining full motion at the metatarsophalangeal joint, gait retraining, and
regaining/maintaining full strength. Most of these concerns are frankly secondary to the healing of the osteotomy/fusion. Motion can typically be regained once healing of the bones is assured.