The Aetiological Factors Cited in the Literature for the Development of Hallux Rigidus - Article Example

Discuss the main aetiological factors that have been cited in the literature for the development of hallux rigidus. Hallux rigidus is a degenerativeosteoarthritis process that is typically characterized by the gradual and progressive loss of range of motion in the metatarsophalangeal joint, with clear and observable dorsal or periarticular osteophyte formation. Factors that are found to be associated with hallux rigidus include a flat or chevron shaped joint, hallux valgus interphalangeus, metatarsus adductus, bilaterally in individuals who have a positive family history and unilaterally in individuals with a trauma history. Hallux rigidus shows a definite bias towards the female gender (Shurnas, 2009). There is no universally accepted theory on the cause of hallux rigidus. Essentially there are two schools of thought. One school of thought takes the stand that hallux rigidus starts in adolescence, but clinically presents itself in adulthood while the other school of thought believes that hallux rigidus in adolescence is different from hallux rigidus in adulthood. However, several specific causes have been attributed to the development of hallux rigidus under different categories made up of the traumatic category, iatrogenic category, inflammatory disorders, congenital factors, vascular issues and as an acquired condition (Coleman & Pomeroy, 2007). Table – 1 shows the aetiological factors associated with the development of hallux rigidus. Table -1 Aetiologies of hallux rigidus Category Specific cause Traumatic Single-event trauma and Micro-trauma Iatrogenic Post-bunion surgery and Elevation of first ray Inflammatory Disorders Rheumotoid, Gout and Seronegative arthritis Congenital Long first ray, Irregular ball and socket of the first metatarsophalangeal joint, long and narrow foot, Pronated foot and Hallux elevatus primus Vascular Avascular necrosis of the first metatarsal head Acquired Obesity and Shoe wear (Coleman & Pomeroy, 2007) The theory that is most commonly seen on the aetiology of hallux rigidus is Hallux elevatus primus, but it is also mired in debate. Hallux elevatus primus is the term that for describing the elevation of the first ray in comparison to the second ray. The proposed mechanism in the involvement of hallux elevatus primus in the aetiology of hallux rigidus is that the elevation of the first ray permits the flexor hallucis brevis to subflux the proximal phalanx of the big toe plantarward, when the heel is raised in gait, since the flexor hallucis brevis contracts. Joint mechanics get changed when the first metatarsophalangeal joint is subfluxed towards the plantar, as the joint is unable to completely dorsiflex, since the dorsal lip of the proximal phalanx impinges on the dorsal metatarsal head. This repetitive micro-trauma forms the basis of this theory in the development of hallux rigidus (Coleman & Pomeroy, 2007). Another theory on the aetiology of hallux rigidus suggests that when the first ray is not elevated the proximal phalanx remains reduced, since contraction in the flexor hallucis brevis is counter-balanced by the force exerted back by the floor. In contrast elevation in the first ray is elevated the possible consequence is that the plantar fascia may get tightened to the first toe. This tightening of the plantar fascia leads to limitation in the dorsiflexion of the first toe, when it is attempted and the dorsal articular surface of the phalanx will impinge on the metatarsal head (Coleman & Pomeroy, 2007). In spite of these theories appearing to have a sound basis, the problem that arises in the acceptance of these theories is that they are yet to be proved and in addition evidence from one study suggests to the contrary, with the findings that there is no relation found between first metatarsal mobility and hallux rigidus. The study goes further to suggest that hallux rigidus is associated with hallux valgus interphalangeus, bilateral involvement where there is a family history, unilateral involvement where there is trauma history the female gender, and the presence of a flat or chevron-shaped metatarsophalangeal joint (Coughlin & Shurnas, 2003). The frequent encountering of the condition of flexible pes planovalgus deformity in hallux rigidus has given to rise to its role in the aetiology of hallux rigidus. Pes planovalgus deformity is typified by hypermobility in the first ray and it is generally taken that the flexible pes valgus experiences compensation in all planes of the motion. The predominant plane of compensation influences whether an individual develops hallux valgus or hallux rigidus. Transverse and frontal plane compensation predisposes an individual for hallux vagus deformity, while sagittal plane compensation makes for hallux rigidus deformity. The length of the ossesous segments that constitute the first ray and its relation to the lesser tarsus also finds a place in the aetiology of hallux rigidus. This association stems from the possibility of an elongated first metatarsal causing excessive loading of the joint and the consequent adaptive and degenerative changes. There is also the possibility of a too short first metatarsal playing an indirect role in the development of hallux rigidus. This is based on the possibility that individuals with a short first metarsal are likely to experience lesser metatarsalgia and consequently grip the ground with the hallux to try and reduce the symptoms in the lateral forefoot. This repeated hyperactivity of the flexor hallucis brevis could cause adaptive contracture of the flexor hallucis brevis and subsequent loss of motion. In a similar manner it is possible for any condition that causes lesser metatarsalgia to be involved in the development of hallux rigidus irrespective of the length of the first metatarsal. An example of this is retrograde pressure arising from a long proximal phalanx against the first metatarsophalangeal joint (Chang & Camasta, 2001). Injuries to the first metatarsal or the first metatarsophalangeal joint in adolescence are also believed to be a likely cause of hallux rigidus. This stems from malunited fractures of the first metatarsal bone leading to iatrogenic type of metatarsus primus elevation. Such a belief in the aetiology of hallux rigidus arises from the observation of painful hallux rigidus as a consequence of stubbing or crushing injuries of the hallux or wearing of ill-fitting in adolescent patients. Arthritic conditions like gout can also cause hallux rigidus. Another likely cause of hallux rigidus are post-surgical complications like those arising from bunion surgery, wherein malunion of a first metatarsal osteotomy can cause sagittal plane elevation or excessive shortening of the first metatarsal bone (Chang & Camasta, 2001). While evaluating the several theories on the possible aetiology of hallux rigidus, it must be borne in mind that the involvement of these theories in the aetiology of hallux rigidus including metatarsus elevatus and excessive length are yet to be proved and in addition no accurate manner to diagnose these structural deformities have been given (Haddad, 2000). Bonney and Macnab 1952, evaluating the causes of hallux rigidus in patients at the Royal National Hospital from 1920 to 1950 report a higher proportion in women than men at 2:1. They however condition this finding with the observation this does not mean that there is such a high bias in favour in women, as it is quite likely that with the first symptoms of pain in hallux rigidus men may opt to wear looser shoes, while women continue to wear tight wearing shoes and thereby aggravating the problem. The authors also report that a family history of hallux rigidus is responsible for an early onset of symptoms. In addition they found that primary cause of hallux rigidus is the first metatarsal extension, though other causes are involved (Bonney & Macnab, 1952). Geldwert et al 1992, support the premise that the most important aetiological factor in hallux rigidus as metatarsus primus elevatus, but in addition to the structural cause of elevated first ray or functional cause due to long first metatarsal, also suggests additional functional causes as mid foot and rear foot pathology leading to excess pronation. Goodfellow 1965 is however of the view that osteochondritis dissecans of the head of the first metatarsal is the major contributory factor to hallux rigidus, which develops in early childhood as a result of external causes or injuries or failure of the mechanics of the foot that make the susceptible to recurrent injury or continued strain. It is this accumulation of ill-defined mechanical insults that gradually lead to the degeneration of the joint (Goodfellow, 1965). The history of knowledge on hallux rigidus begins in 1887, when it was first described. Several aetiological factors have been put forward as to the cause of hallux rigidus, but there has been no fully proven scientific evidence to accept any of the aetiological postulations on hallux rigidus. A frequently put forth postulation is that static and dynamic imbalances in the first metatarsophalangeal lead to this condition. Evaluation of a mathematical model of the joint that was subjected to both normal and abnormal physiological loads using finite-element analysis studies provides significant support for increase in tension of the plantar fascia as the reason for abnormal stress on the articular cartilage in place of mismatch in the articular surfaces or sub clinical muscular contracture. Evidence from the study of this mathematical model therefore suggests that it is the abnormal stress on the articular cartilage and not the mismatch of articular surfaces or sub clinical muscular contractures that causes hallux rigidus (Flavin et al, 2008). The full list of aetiological factors involved in the development of hallux rigidus thus consist of many factors. It could be a manifestation of a generalized systemic osteoarthrosis. It may also develop from traumatic events like stubbing of the big toe that causes damage to the articular cartilage or osteochondritic lesions of the first metatarsophalangeal joint in adolescents. Congenital variations like long first ray, irregular ball and socket of the first metatarsophalangeal joint, long and narrow foot, pronated foot and abnormal gait are other possible factors. Ill-fitting foot wear and bad gait have also been implicated in the development of hallux rigidus. Inflammatory disorders of rheumatoid and seronegative arthritis van lead to synovitis in the first metatarsophalangeal joint resulting in hallux rigidus. Metabolic disorders such as gout not only mimic hallux rigidus, but also lead to degenerate patterns that are associated with hallux rigidus (Sherref & Baumhauer, 1998). Literary References Bonney, G. & Macnab, I. 1952, ‘Hallux Vagus and Hallux Rigidus: A Critical Survey of Operative Results’, The Journal of Joint and Bone Surgery, vol.34B, no.3, pp.366-385. Chang, T. J. & Camasta, C. A. 2001, ‘Hallux Limitus and Hallux Rigidus’, in McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery, Volume 1, Third Edition, eds. Alan S. Banks, Michael S. Downey, Dennis E. Martin & Stephen J. Miller, Lippincott Williams & Wilkins, Philadelphia, PA., 679-714. Coleman, A. & Pomeroy, G. C. ‘First Metatarsophalangeal Disorders’’, in Foot and Ankle: Core Knowledge in Orthopaedics, eds. Christopher W. DiGiovanni & Justin Greisberg, Elsevier Mosby, Philadelphia, PA., pp.119-128. Coughlin, M. J. & Shurnas, P. S. 2003, ‘Hallux rigidus: demographics, etiology, and radiographic assessment’, Foot & Ankle International, vol.24, no.10, pp.731-743. Flavin, R., Halpin, T., FitzPatrick, D., Ivankovic, A. & Stephens, M. M. 2008, ‘A finite-element analysis study of the metatarsophalangeal joint of the hallux rigidus’, Journal of Bone and Joint Surgery, vol.90-B, no.10, pp.1334-1340. Geldwert, J. J., Rock, G. D., McGrath, M. P. & Mancuso, J. E. 1992, ‘Cheilectomy: Still a Useful Technique for Grade I and Grade II Hallux Limitus/Rigidus’. The Journal of Foot Surgery, vol.31, no.2, pp.154-159. Goodfellow, J. 1965, ‘Aetiology of Hallux Rigidus’, Proceedings of the Royal Society of Medicine, vol.59, pp.821-824. Haddad, S. L. 2000, ‘The use of osteotomies in the treatment of hallux limitus and hallux rigidus’, Foot and ankle clinics, vol.5, no.3, pp.629-661. Sherref, M. J. & Baumhauer, J. F. 1998, ‘Hallux Rigidus and Osteoarthrosis of the First Metatarsophalangeal Joint’, The Journal of Bone and Joint Surgery, vol.80A, no.6, pp.898-908. Shurnas, P. S. 2009, ‘Hallux rigidus: etiology, biomechanics, and nonoperative treatment’, Foot and ankle clinics, vol.14, no.1, pp.1-8. Read More