Simple weight-bearing x-rays of the foot with anteroposterior and lateral views are usually sufficient to plan treatment of lesser toe deformities. Most patients with isolated lesser toe deformity can be advised on treatment without further investigation. However, in patients who might have inflammatory arthritis as the underlying cause, a routine full blood count and measurement of erythrocyte sedimentation rate and levels of C-reactive protein and rheumatoid factor may be indicated. Patients with progressive or asymmetrical deformity should be investigated for associated central or peripheral neurological conditions, with spinal and possibly cranial MRI or nerve conduction studies as well as screening for diabetes.
Rapid progression of deformity in an erythematous, hot foot is a red flag, especially in a patient with known or suspected diabetes or other cause for peripheral neuropathy. There should be a high suspicion of Charcot neuroarthropathy, and patients require urgent referral to an orthopaedic foot and ankle specialist or a multidisciplinary ‘at-risk foot’ service.
Most older patients with isolated lesser toe deformity or pain can be treated initially with nonsurgical techniques. General advice on foot care and the involvement of a chiropodist to deal with troublesome callus and corns are sufficient in many cases. This, together with education about appropriate footwear selection (shoes with a broad and deep toe box area and soft uppers), is often all that is required in older people.
If conservative options fail then referral to an orthopaedic surgeon is warranted. Patients should be counselled that surgery to treat lesser toe deformities may include lengthening of extensor tendons, flexor tenotomies, osteotomies of the phalanges and surgical fusion of the affected joints of the small toes. These procedures are simple to perform but often involve insertion of a wire or implant to stabilise the toe. After surgery, patients must wear a stiff-soled ‘postoperative’ shoe for six weeks to protect the fusion site. Patients can then return to normal footwear after removal of any wires in theatre or the clinic. Implants are not removed.
Hallux valgus (bunion)
Bunions are complex deformities that cover a spectrum from true hallux valgus to bony projections associated with arthritis of the first MTP joint, as in hallux rigidus. However, patients often use the term bunion to refer to any deformity of the medial border of the foot with a prominence over the great toe MTP joint. Bunions or hallux valgus have a reported prevalence of up to 35% in patients over the age of 65 years.4
There is a strong family history in up to 90% of patients with hallux valgus.5 The link to use of inappropriate footwear is not clear cut. Hallux valgus occurs in many populations that do not wear shoes, although with a much lower prevalence than in shoe-wearing populations.
Hallux valgus is actually a complex series of deformities that lead to lateral deviation of the big toe. The change in shape of the foot and associated change in the mechanics of weight-bearing cause discomfort when the patient wears enclosed footwear. The lateral deviation and pronation of the great toe cause the normal sesamoid weight-bearing apparatus to lose function and overload the lesser toe MTP joints. This can lead to forefoot pain and often to lesser toe abnormalities such as hammer or claw toes (Figure 2).
In severe cases of hallux valgus the great toe may deviate so far laterally that it causes the second toe to cross or ride over it. The term crossover toe is reserved for a medial deviation of the second toe at the level of the MTP joint, leaving a gap between the second and third toes. This can occur with or without a hallux valgus deformity (Figure 3). Crossover toe is associated with disruption to the plantar plate complex.
It is crucially important to identify the patient’s exact symptoms and whether they have presented because of these symptoms or other reasons. Often an older person has lived with the foot deformity for many years and presents because of fear that it will progress and they will ‘end up like my mother/grandmother/aunt’ rather than specific symptoms. Older patients are also sometimes under pressure from family to have their ‘bunions sorted’. The progression of hallux valgus is slow, and if there is significant deformity then it has probably been present for many years and is likely to have been well tolerated by the patient. If deformity has progressed and is now causing local pressure symptoms or forefoot pain then surgical treatment is an option. Surgery is generally not recommended for people with asymptomatic hallux valgus.
Simply observing the patient when standing and walking provides most of the required information in hallux valgus. Do they have evidence of breakdown of the medial skin over the MTP joint? Do they walk on the lateral border of the foot to avoid weight- bearing on a painful hallux or second metatarsal as with transfer metatarsalgia? The general weight-bearing alignment of the foot should also be inspected. Hallux valgus is often seen in association with flat foot deformity in older patients. When the patient is examined sitting, is there evidence of corns or callus formation? Is the MTP joint of the great toe painful when moved passively? If so then there may be a degree of arthritic change affecting the joint.