The common deformity of the first ray known as a “bunion” is a progressive positional deformity which leads to pain from shoe pressure and biomechanical malfunction of the first metatarsal phalangeal joint. While the medial bump is widely considered the etiology of pain, malalignment results in progressive joint adaptation and degeneration. The exact biomechanical fault and the etiology of the progression of the deformity remain unclear. The origin of the terminologies describing this first ray deformity deserves specific attention due to the common historical misapplications of terms used to describe disorders of the first metatarsophalangeal joint (MTPJ ). Bunion is derived from the Latin term bunio, meaning turnip. This term has been applied to describe any enlargement of the first MTPJ and therefore poorly defines the deformity [7, 22]. It was not until 1870, when Carl Hueter, a German surgeon, coined the term hallux valgus to more accurately describe the condition [28]. Hueter defined this first ray deformity as a subluxation of the first MTPJ in the transverse plane with lateral deviation of the great toe and medial deviation of the first metatarsal. However, the term hallux valgus raised questions on whether the laterally deviated hallux should be the primary focus of the deformity. Therefore, half a century later, Truslow [66] proposed the term metatarsus primus varus to replace hallux valgus in the belief that the medially deviated first metatarsal is the primary level of deformity. This is in fact the first time the primary level of deformity is considered to be located at the first metatarsal cuneiform joint.

It is important to note that valgus and varus are used to describe transverse plane deviations in the aforementioned studies. A later term hallux abducto valgus was developed to incorporate the frontal plane eversion of the great toe in defining this deformity. The term valgus when used in this text describes frontal plane rotation and therefore differs from that used by Hueter who used it to describe the transverse plane position. Likewise, the term varus used by Truslow to describe the transverse plane deviation of the metatarsal is also used to describe frontal plane inversions in the foot. Confusion over the correct terminology to describe this first ray deformity still exists, and a uniformly accepted term is needed to accurately capture the nature of the deformity and to facilitate effective communication among providers. In an effort of achieving this, Dayton and colleagues [18] proposed the term hallux abducto valgus with metatarsus primus adducto valgus to address the multiplanar components of this deformity evident by previous cadaveric and clinical studies [16, 17, 54]. A more detailed description of the anatomy and clarification of the terminology of this first ray deformity will be discussed in Chap. 5.

The true prevalence of HAV in the general population has never been uniformly established in the literature, although a wide range of estimates were presented in multiple reports ranging from 0.9% to 74% [2, 44, 61]. Previous studies demonstrate that HAV may more commonly correlate with the female gender and elderly individuals [51]. A systematic review conducted in 2010 [52] determined the prevalence of HAV to be 23% in adults aged 18–65 years and 35.7% in individuals over 65 years of age. The study also found a higher prevalence rate in females (30%) compared to males (13%), supporting the predilection of HAV in the female population as observed by other studies.

Many attribute this higher prevalence to the high-fashion yet less physiologic footwear worn by the females [14, 34]. It has been long established that HAV is associated with a habitually shod population as the incidence of HAV is very low in unshod people [55, 65]. Therefore, the ill-fitting and constricting footwear may further predispose individuals to the development of HAV deformity [12]. However, what may be more important are the hereditary factors as suggested by more recent literature [11, 58]. Studies report adult males and females have a positive family history with a pattern of maternal transmission. There may be a greater genetic predisposition for HAV in the female population [11, 12, 50]; however, whether this trait is associated with X-linked dominant transmission, autosomal dominant transmission, or polygenic transmission cannot be determined at this time.

The age of onset for HAV is still a topic of debate. In Piggott’s original series of adult patients, 95% of patients recalled the onset of deformity before 20 years of age [57]. A study conducted by Hardy and Clapham proposes an early age of onset of the deformity with 46% of HAV deformities occurring before age 20 [25]. Other studies have suggested the mean onset of deformity to be in the third through fifth decades with an equal incidence rate in the second through fifth decades [13, 14]. A later study suggested that while the mean age of onset may vary, very few HAV deformities developed in the first decade, and therefore most HAV deformities develop and progress after skeletal maturity [12]. The exact age of onset is not agreed upon, and there does not seem to be a correlation between the age of onset and severity of the deformity. This may be because the recognition of the deformity by the patient is in many cases subjective and dependent on the onset of symptoms and not the awareness of the deformity.

HAV deformity has commonly been associated with other global foot deformities and dysfunction. A contracted Achilles tendon can theoretically contribute to the development of HAV deformity due to the repetitive medial stress to the hallux when the foot rolls on the medial aspect and externally rotates during gait. The ankle equinus deformity is typically defined as less than 10 degrees of ankle dorsiflexion [20]. Recent studies show no correlation between ankle dorsiflexion and the magnitude of HAV [12, 13]. In fact, according to one study by Grebing and Coughlin, 81% of individuals without the deformity demonstrate less than 10 degrees of ankle dorsiflexion, whereas this limited ankle dorsiflexion is found in only 67% of those with the deformity, further suggesting that ankle equinus may not be a contributory factor of HAV [24]. Similarly, the literature on the association of pes planus and HAV is unclear. While some authors believe that HAV tends to occur in pronated foot types [30, 67], no data are available to quantify this relationship. In addition, no increased incidence of HAV in patients with pes planus was observed in multiple studies [35, 59, 62], suggesting pes planus may not be a significant factor in the development of HAV. Nonetheless, patients with pes planus may have a more rapid progression of the deformity due to the altered biomechanics [33].

HAV deformity has also been discussed as associated or even caused by first ray hypermobility. This concept is first introduced by Morton [48] and later popularized by Lapidus [38]. However, whether this truly exists is still controversial as the level of the hypermobility, the proper diagnostic exam, and clinical imaging modality to assess the hypermobility cannot be agreed upon among providers [27, 36, 39, 49]. It is beyond the scope of this chapter to discuss the existing schools of thoughts and evidence in the current literature regarding the association of first ray hypermobility and HAV deformity. A more detailed review of the mechanical theories will be presented in Chap. 4. Other associated diseases in HAV include ligamentous laxity such as Ehlers-Danlos and Marfan syndrome, generalized neuromuscular diseases, cystic degeneration of the medial capsule of the first MTPJ , neuroma, and previous amputation of the second metatarsal. Discussion of the many possible etiologies of the bunion deformity is discussed in Chap. 3.

As the most common deformity affecting the hallux, multiple studies have shown that HAV is strongly associated with impaired health-related quality of life (HRQOL ) [1, 10, 40, 70]. Pain is the most common and significant chief complaint in patients with HAV deformity, with 70–75% of pain located over the medial eminence and 40–48% of pain caused by intractable plantar keratosis and metatarsalgia [12, 42]. In addition, HAV is associated with impaired balance, altered gait patterns, and increased risk of falls particularly in the elderly population [45, 46].

Whether the severity of HAV deformity is correlated with pain intensity and reduced quality of life is still unclear at this time. Pain intensity may be influenced by lifestyle, demographic, and cognitive factors [1, 29]. It has been reported that increased HAV deformity leads to increased foot pain and progressive reduction in functional scores of both the general health (SF-36) and foot-specific (FPDI) surveys [46]. In addition, an increasing severity of HAV directly corresponds to a reduction in both general health and foot health among the older adults [40]. However, Hurn et al. [29] found that foot pain associated with HAV was not determined by severity of the structural deformity or first MTPJ osteoarthritis, but rather by a patient’s general health status, educational attainment, and level of physical activity. The authors also concluded that altered foot and ankle biomechanics such as weakness with hallux plantarflexion significantly contributed to increasing foot pain [29]. This flexor weakness of the hallux is also observed in the elderly population with disabling foot pain and reduced HRQOL [47], suggesting the importance of assessing dynamic foot and ankle biomechanics rather than focusing on a static structural deformity. A recent study by Yamamoto et al. [70] found that although quality of life was lower in patients with untreated HAV deformities, this reduction in quality of life was not correlated with severity of the hallux deformity, degree of dislocation of the second MTPJ , age, or BMI. Interestingly, pain severity and impaired foot function are directly correlated with increased HAV angle in the nondominant foot according to one study in the female population [10], further elucidating the need to assess the dynamic biomechanics of the lower extremities.

The impact of HAV is not just limited to pain and alteration of physical function. It has also been shown to affect the mental health and cognitive perception and may lead to detrimental effects on self-esteem [46]. Patients with untreated HAV exhibit significant concerns over foot appearance and difficulty with footwear [53]. In fact, free choice of footwear is significantly associated with improved HRQOL in one study [63], suggesting the importance of evaluating patients’ footwear concerns when treating this deformity. A holistic approach should be employed in the treatment of HAV rather than an isolated correction of the structural deformity. A patient’s chief complaint must be evaluated in the context of occupation, level of physical activity, preferences of footwear, health history, goals, and expectations of seeking the treatment to determine the optimal treatment option and physical rehabilitation for the patient.

A timely question in today’s healthcare reform environment is this: how many corrective surgeries are performed and what is the cost of surgical and nonsurgical care? Hallux abducto valgus surgery is an extremely common occurrence, with reports that more than 200,000 patients have been estimated to undergo hallux valgus surgery in the United States every year [14]. Recent unpublished survey of billing records indicates that there was between 300,000 and 330,000 bunion operations in the United States in 2013 excluding isolated soft tissue corrections (personal investigation). The diversity of insurance products and billing codes for correction as well as the variability in the coding of the deformity and the corrective procedure or procedures makes accurate assessment difficult. Similarly, this diversity of insurance products and nontransparency of billing and coding insulate most patients from the true costs of the healthcare services they consume. Patients are frequently unaware of the overall cost of bunion surgery. A study conducted by Wiley et al. quotes the overall mean bundled price with hospital fees included at $18,332, ranging from $3,542 to 52,207, while the overall mean physician fee quoted was $2,487 and ranges from $800 to 7,934, suggesting an extremely high price variability and a low price transparency for bunion surgeries currently performed in the United States [69]. When reviewing data for Medicare patients, a total of 23,446 procedures for bunion corrections were identified in 2011 with an estimated combined cost of $59.5 million including professional fees and hospital charges and an overall estimated $325.1 million economic burden to the system when indirect factors such as disabilities and workdays lost were considered [6].

There are multiple recent papers identifying recurrence rates of between 25% and 73% based on radiographic evaluation with reported revision rates ranging from 5.56% to 8.19%, thus calling into question our common corrective techniques [21, 32, 56]. The costs of revision or repeat surgeries are not quantifiable with current data, but second or third surgeries certainly increase the overall cost of caring for patients with the deformity. Additionally, there are indirect costs of loss of productivity associated with not only the index procedure but subsequent surgeries as well. It is worth noting that no statistically difference is identified in revision rates among different surgical methods employed for hallux abducto valgus , prompting the necessity to further examine our current practice algorithm for this common deformity [60]. Because complications such as recurrence are common, the cost of bunion surgery has potential to add up for the patient, surgeon, and healthcare system. A more complete understanding of the pathological and normal anatomy will provide a basis for surgeons to design procedures and techniques that will theoretically provide more accurate and durable correction.

Well over 100 procedures have been described for correcting bunions. This variability is based in large part on individual surgeon preference and not necessarily supported by high-level evidence. We have come to accept a very high degree of variability in treating HAV , with surgeons rarely agreeing on the best treatment approach. In fact, differences in the approach to bunion surgery are noted to occur regionally and locally with no semblance of consistency in procedure selection or execution. This extreme variability and lack of consensus calls into question our basic understanding of the problem. As with any problem, we should strive to find the single most efficient and reliable solution, and in situations in which many solutions are perceived to be needed, we should reevaluate the very basis of our thought process. Multiple and repeated minor modifications to any existing technique or system can be defined as a failure of the basic paradigm. Bunion surgery is one area that has such extreme variability that it would suggest that we may indeed need to change our entire foundation for evaluation and management. Using a variety of radiographic algorithms, we attempt to define each bunion as a unique entity based on the degree of positional change, and it is this practice that drives the continued practice of selecting different variations of corrective surgeries.

Treatment variability is one of the factors that has been identified as a potential cause of lower healthcare quality. In fact, much of medicine in the United States remains empirical today as the decision-making process relies more on the medical opinions of the providers and local supply of resources rather than evidence from clinical sciences, thus leading to wide practice variations and healthcare outcomes [68]. One study investigating the quality of care in the United States found that Americans on average received only half of recommended medical care processes [5]. The gap between clinical sciences and bedside medicine is quite substantial. This practice variation, which is characterized by variation in adopting established effective care, variation in choosing preference-sensitive care, and variation in supply-sensitive care, is known as unwarranted variation and has huge implications in both healthcare quality and financial burden to the healthcare system [8, 68]. The abundance of unwarranted variations can be partly attributed to practice algorithms that are not supported by the current medical evidence but rather provider preference [68]. Many providers are more apt to trust their personal experiences and instincts over medical literature. Contrary to popular belief that clinical experience leads to better patient care, a systematic review exploring the relationship between provider experience and quality of care found that providers who have been in practice for more years are less likely to adhere to appropriate standards of care and are correlated with poorer patient outcomes, suggesting the importance of adopting evidence-based medicine and quality assurance strategies in today’s practice environment [9].