Hallux Rigidus Etiology

CHAPTER PREVIEW

CHAPTER SYNOPSIS:

An arthritic disorder of the first metatarsophalangeal joint associated with osteophytes, possible due to cumulative trauma and chronic joint changes. There is limited joint motion and difficulty with shoe-wear plus pain from the underlying process. Hallux rigidus is associated with variations in the shape of the metatarsal head, overuse throughout life, acute joint trauma (e.g., turf toe), or fracture.

IMPORTANT POINTS:

1

Patients present late in the course of the process; with good alignment, there is limited motion and prominent bone at the joint level.
2

Pain is sometimes only related to activity such as walking or running.
3

The metatarsal head often flattens and there is subchondral sclerosis.

CLINICAL PEARLS

1

Higher heels will shift weight toward the distal part of the toe and may cause hyperdorsiflexion of the interphalangeal joint of the toe.
2

The outer soles may show excessive lateral heel-sole wear in patients with hallux rigidus due to supination to avoid dorsiflexion of the affected joint.
3

The lateral radiograph may show a fracture of the dorsal osteophyte or a loose body.

CLINICAL/SURGICAL PITFALLS:

1

Inflammatory arthritis may sometimes present with great toe metatarsophalangeal symptoms and progress to end-stage arthritis with the appearance of hallux rigidus.
2

Gout may present with pain, swelling, and redness in the area of the first metatarsophalangeal joint but does not have the characteristic osteophyte and sclerosis seen on radiographs.

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HISTORY/INTRODUCTION/SCOPE OF THE PROBLEM

Hallux rigidus is characterized by painful restricted motion at the first metatarsophalangeal joint with a particular limitation of dorsiflexion. It is a common disorder of the first metatarsophalangeal joint occurring second only to hallux valgus. This condition has been reported to affect 1 in 40 patients older than 50 years of age.

Hallux rigidus has been recognized clinically for over 100 years. Davies-Colley provided the initial report in 1887 and used the term hallux flexus to describe the relative plantarflexed position of the proximal phalynx in relation to the metatarsal head. In 1888, Cotterill described the same condition but is credited with the phrase hallux rigidus, still the most commonly used expression for the condition. Lambrinudi introduced metatarsus elevatus not only as a descriptive phrase for the condition but also as a pathologic predisposition, a potential theory that still remains unresolved. Numerous other expressions such as dorsal bunion, hallux limitus, hallux dolorosus, and hallux malleus have all been promoted, but the described clinical presentation has all been similar.

The painful restricted motion is often associated with a mechanical block caused by periarticular osteophytes. The exostosis of the first metatarsal head articulates against an osteophyte at the base of the proximal phalynx leading to mechanical impingement. Intraoperative findings reveal periarticular osteophytes extending medially, dorsally, and laterally, often leading to the characteristic horseshoe-shaped collar of bone in this region ( Fig. 33-1 ).

ETIOLOGY

The cause of hallux rigidus has not been determined, although multiple predisposing factors have been revealed. Hallux rigidus has been described in two different populations: a congenital form and an adult acquired degenerative form. The congenital form usually presents in the teenage years through the 20s from a predisposing anatomic factor such as flattening or squaring of the metatarsal. The adult degenerative form typically presents in a relatively older population in their 40s and 50s, usually as a result of predisposing high-impact activities such as running or dancing. The adult form may be a continuation of the congenital form, although in most cases the exact cause is unknown.

The most common cited cause is trauma, which can begin as a single episode such as an acute sprain or turf toe to intra-articular fracture or crush injury. In a patient who sustains an acute injury to the first metatarsophalangeal joint, forced plantarflexion or hyperextension can create compressive forces across the joint. This often initiates or propagates an acute chondral or osteochondral injury. What may begin as an acute sprain or turf toe can evolve into chronic discomfort. A clear traumatic episode is most likely the cause of unilateral hallux rigidus based on long-term follow-up. Chronic repetitive trauma such as running has also been described as a theory for the development of hallux rigidus. The disorder possibly results from repetitive hyperextension of the first metatarsophalangeal joint with chronic gradual attenuation of the plantar plate and subsequent instability leading to arthrosis.

The adolescent can also be associated with an osteochondritis dissecans lesion identified on radiographic examination or verified by magnetic resonance imaging. In 1933, Kingreen reported that osteochondritis dissecans led to development of hallux rigidus. His initial description described fragmentation of the epiphysis of the proximal phalynx initiating the arthritic process. Goodfellow proposed that the osteochondritis dissecans lesion in childhood creates a defect leading to secondary slow-remodeling collapse and subsequent abnormal motion in the forefoot. McMaster described seven adolescent patients with symptoms of hallux rigidus who had a characteristic articular defect of approximately 5 mm located directly beneath the dorsal lip of the proximal phalanx. At times, a family history may suggest a genetic component. Bonney and MacNab noted a 50% incidence of a family history in those with onset in teenage years. Coughlin and Shurnas found in their series that nearly 95% of patients with a positive family history of great toe problems had bilateral hallux rigidus and that nearly 80% of all patients with hallux rigidus had a positive family history.

Other hypotheses have suggested anatomic abnormalities as the primary cause of rigidus. Nilsonne and McMurray in the 1930s both described an abnormally long hallux as a possible cause. They proposed an abnormally long first metatarsal increases stress in the metatarsophalangeal joint during toe-off, predisposing an individual to hallux rigidus. They also suggested that the excessively long toe requires a longer shoe, which in turn requires constant ontraction of the great toe flexors to grip the shoe while the person is walking. This gripping can lead to inflammation and secondary spasm, therefore limiting motion at the metatarsophalangeal joint at the great toe. Jansen in 1921 proposed that a flat or pronated foot similarly caused extra strain on the first metatarsophalangeal joint leading to rigidus.

Lambrinudi proposed the controversial theory of metatarsus primus elevatus in 1938. Theoretically, an abnormally elevated first metatarsal causes excessive flexion of the great toe during gait and subsequent development of flexion contracture at the first metatarsophalangeal joint. These abnormal mechanics cause limitation of motion and hallux rigidus. Others, such as Jack, in 1940, postulated that with the elevated first metatarsal there was a compensatory contracture of the flexor hallucis brevis. This contracture pulls the proximal phalanx inferiorly, impinging its dorsal rim into the metatarsal head and leading to localized degenerative changes in the articular cartilage ( Fig. 33-2 ).