A Review of Bunionettes

Introduction

A bunionette is also commonly termed a tailor’s bunion and is typically defined as a lateral prominence of the fifth metatarsal head (8). There are multiple theories as to the etiology of a bunionette. One risk factor for developing a bunionette is pes planus, as it leads to a hindfoot valgus and a compensatory rotation of the fifth metatarsal head laterally (8). Other risk factors for developing a bunionette are a plantarflexed fifth metatarsal shaft, lateral bending of the fifth metatarsal shaft, and a prominent metatarsal head (7). There are other anatomical risk factors for developing a symptomatic bunionette, including a prominent lateral fifth metatarsal head and a “dumbbell” shape fifth metatarsal. Bunionette deformities are seen more commonly in females (5).

Diagnosis

Patients typically complain about lateral sided foot pain with constrictive shoeware (7). Examination should start with the patient standing to evaluate for pes planus or a hindfoot valgus. A concomitant hindfoot valgus with a bunionette is referred to as a “splay foot” (3). Clinical examination typically reveals a callus overlying the fifth metatarsal head on either the lateral, dorsolateral, or plantar surface (5,8). There may also be lateral eminence swelling (7). Hyperkeratotic lesions can also be seen due to continuous pressure over the lateral portion of the metatarsal (5).

Image 1. Lateral eminence swelling (7)

Standard radiographs should be obtained with lateral, AP, and oblique views taken (7,8). Typical angles measured are the metatarsophalangeal angle 5 (MTPA) and the 4-5 intermetatarsal angle (4-5 IM angle).

Image 2. Demonstration of the metatarso-phalangeal-5 angle and 4-5 intermetatarsal angle (8)

Classification is determined based on the radiographs. Type I show enlarged fifth metatarsal head or lateral exostosis. A typical metatarsal head measures less than 13mm (8). Type II shows an increased lateral bend with a normal 4-5 intermetatarsal angle, and type IIIs show an increased 4-5 intermetatarsal angle (8).

Image 3. Coughlin staging – Image A is a Type I, Image B is a Type II, and Image C is a Type III (5)

Treatment

Nonsurgical treatment typically involves starting with the patient wearing a wide based shoe (8). Any keratosis found can be debrided or padded (8). Providers should also correct for any pes planus with orthotics (8). Corticosteroid injections into the fifth MTP joint and/or overlying inflamed bursa can also be done for temporary pain relief (7).

There are multiple surgeries that exist that look to resolve the abnormal MP-5 or 4-5 IM angle. Surgery can be broken down into exosectomy and metatarsal osteotomy (8).

Conclusion

A bunionette deformity is commonly found and is associated with multiple risk factors that lead to the development of lateral forefoot pain. Patients are typically treated with conservative treatment as a first line. Multiple surgeries exist for those patients who continue to have symptoms.

Gregory Rubin, DO

rubinsportsmed.com

– Read More Foot Pain: https://www.sportsmedreview.com/by-joint/foot/

References

1) Ajis, Adam, et al. “Tailor’s Bunion: A Review.” The Journal of Foot and Ankle Surgery: Official Publication of the American College of Foot and Ankle Surgeons, vol. 44, no. 3, 2005, pp. 236–45. PubMed, https://doi.org/10.1053/j.jfas.2005.02.005.

2) Clinical Practice Guideline Forefoot Disorders Panel, et al. “Diagnosis and Treatment of Forefoot Disorders. Section 4. Tailor’s Bunion.” The Journal of Foot and Ankle Surgery: Official Publication of the American College of Foot and Ankle Surgeons, vol. 48, no. 2, 2009, pp. 257–63. PubMed, https://doi.org/10.1053/j.jfas.2008.12.006.

3) Frontera, Walter R., et al., editors. Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, Pain, and Rehabilitation. Fourth edition, Elsevier, 2019.

4) Michels, Frederick, and Stéphane Guillo. “Bunionette: Is There a Minimally Invasive Solution?” Foot and Ankle Clinics, vol. 25, no. 3, Sept. 2020, pp. 425–39. PubMed, https://doi.org/10.1016/j.fcl.2020.05.004.

5) Bertrand, Todd, and Selene G. Parekh. “Bunionette Deformity: Etiology, Nonsurgical Management, and Lateral Exostectomy.” Foot and Ankle Clinics, vol. 16, no. 4, Dec. 2011, pp. 679–88. PubMed, https://doi.org/10.1016/j.fcl.2011.08.003.

6) Shimobayashi, Mikio, et al. “Radiographic Morphologic Characteristics of Bunionette Deformity.” Foot & Ankle International, vol. 37, no. 3, Mar. 2016, pp. 320–26. PubMed, https://doi.org/10.1177/1071100715614923.

7) Shi, Glenn Guangyu, et al. “Management of Bunionette Deformity.” The Journal of the American Academy of Orthopaedic Surgeons, vol. 26, no. 19, Oct. 2018, pp. e396–404. PubMed, https://doi.org/10.5435/JAAOS-D-17-00345.

8) Cohen, Bruce E., and Christopher W. Nicholson. “Bunionette Deformity.” JAAOS – Journal of the American Academy of Orthopaedic Surgeons, vol. 15, no. 5, May 2007, p. 300. journals.lww.com,