Tag Archives: sesamoids

The Clinical Importance of the Os Peroneum: A Dissection of 156 Limbs Comparing the Incidence Rates in Cadavers versus Chronological Roentgenograms

by Brion Benninger, MD 1 , Jessica Kloenne 

The Foot and Ankle Online Journal 4 (2): 2

Introduction: The purpose of this study was to assess radiograph incidence versus cadaver incidence rates of the os perineum (OP) within the fibularis (peroneus) longus tendon (FLT) and to assess why broad variants have occurred in previous radiograph and cadaver studies. The OP or sesamoid bone in the FLT has a history of controversy regarding the terminology and frequency. Recent histological studies have proven sesamoid terminology. Cadaver studies have revealed high incidence rates (IR), yet virtually all texts and atlases exclude it. Clinicians recognize it in routine foot radiographs. No studies have compared IRs between cadavers and injured patients of the general population.
Methods: A literature search of texts, atlases, journals and websites was conducted identifying incidence of OP within the FLT. Dissection of 82 embalmed cadavers (M 52, F 30) identified the IR of the OP. Oblique foot radiographs from 1,025 individuals were examined.
Results: A literature review revealed OP in 20% of atlases, 7.69% in texts, and previous cadaver study results are 46%, 90%, and 14.9%. This study’s cadaver results reported an IR of 88.46% with an average age of 78.1 (45 – 89yrs). Radiographic results revealed 15.12% incidence with an average age 41.97 (10 – 89yrs). The average IR from 10 to 70 years was 13.32%. From 70 onwards it increased to 32.98%. The p value per decade from radiographic analysis was 0.0005.
Conclusion: This study suggests there is a high IR of an OP in cadavers (88.46%). This may be a result of the average age of cadavers 78.1 and the technique used to locate the OP. Radiographic results were significantly lower and may be explained by an age factor. Radiographs reviewed were from an emergency room where the majority of patients receiving foot radiographs were between the ages of 19 – 45. The clinical importance has been understated regarding the area of the os peroneum, which can be mistaken for styloid and Jones’ fractures.

Key words: Os peroneum, incidence, foot injury, sesamoid bone, Jones fracture, styloid process.

Accepted: January, 2011
Published: February, 2011

ISSN 1941-6806
doi: 10.3827/faoj.2011.0402.0002


The purpose of this study was to examine the important clinical relevance of the ‘os peroneum’ (OP) within the fibularis longus (FLT) by investigating the incidence of the OP between cadaveric specimens and radiological images.

The ‘os peroneum’ within the fibularis (peroneus) longus tendon has a history of controversy regarding its incidence in both individual and combined radiographic and cadaver studies. Radiographic and cadaveric studies have reported incidence rates of the OP within the FLT, however, a limited number of anatomical textbooks and atlases used by healthcare professionals and trainees mention or illustrate the OP.

Research to date reports a wide variation of incidence rates (IR), which are different in radiographic and cadaveric research. Previously Cilli, et al., in 2005 conducted a radiographic study on males only reporting 31.8% IR. A cadaveric study was conducted by Muehleman, et al., in 2009 which reported a 46% IR. Despite the various studies conducted thus far, no previous studies have conducted a comparison of incidence rates between radiographs and cadavers from separate populations. The objective of this research project was to assess radiograph incidence versus cadaver incidence rates of OP within the FLT and to assess why broad variants have occurred in previous radiograph and cadaver studies. (Fig. 1 and Fig. 2)

Figure 1 Os peroneum in the fibularis longus tendon. (Reproduced with kind permission from Lippincott Williams & Wilkins, Grant’s Anatomy, 12th edition.)

Figure 2 Location of os peroneum in the foot. (Reproduced with kind permission from Elsevier, Gray’s Anatomy, 40th edition.)

Methods

A literature search was conducted of anatomical texts and atlases, specialty texts, journals and websites regarding the presence or incidence of the OP within the FLT. Oblique foot radiographs from 1,025 individuals (range 10-89) were examined to identify OP within the FLT. (Fig. 3A and 3B) Dissection of 82 (156 sides) embalmed cadavers (52M, 30F) with a mean of 78.1 years (range 45- 89) was performed to identify the incidence rate of the OP within the FLT. A skin incision was made from the fifth toe to the styloid process distal to proximal along the lateral border of the foot. Then an oblique incision was made to the lateral malleolus to expose the FLT. (Fig. 4A)

Figure 3A and 3B Oblique radiographs of the OP in the FLT. (A and B)  (Thanks to the OHSU Radiology Department for radiograph.)

At the styloid process a horizontal incision was made along the surface of the foot to the opposite side, then exposing the FLT within the tunnel it traverses. The FLT was freed from its attachment point distally and reflected back. Palpation of the FLT was performed to identify the OP. A longitudinal incision was performed 2cm proximal and distal to the OP and then opened to reveal the ‘sesamoid bone’s’ existence or not. (Fig. 4B) A second examiner palpated and analyzed the longitudinal incision and reported their findings. A paired t-test was conducted on the radiographic data.

Figure 4A and 4B OP within the FLT in a cadaver.

Results

The literature search revealed the OP within the FLT was discussed in anatomy texts (7.69%), contemporary atlases (20%) and specific imaging texts (16.6%). This study’s radiographic evaluation of OP within the FLT from 1,025 individuals with a mean age of 41.97 years had an incidence rate of 15.12% overall.

Incidence by ten-year increments revealed 12.16% for 10-19 years, 11.31% for 20-29 years, 13.87% for 30-39 years, 16.17% for 40-49 years, 15.15% for 50-59 years, 10% for 60-69 years, 41.38% for 70-79 years, and 19.44% for 80-89 years. The number of radiographs analyzed per ten-year increment was from approximately 100 individuals. (Graphs 1 and 2) The p value for the radiographic images was 0.0005. In this study, the incidence rate of the cadaver dissections was 88.46% with a mean age of 78.1.

Graph 1 Radiographic incidence of the OP within the FLT per ten-year increment.

Graph 2 Identification of the OP within the FLT in educational texts.

Discussion

The OP is a sesamoid bone that is located within the FLT. [12] The shape of the OP can be round, oval, triangular, irregular and can also be found as bipartite or multipartite. [6,7]

The etiology of the OP is unknown; however, it has been thought that it arises from both mechanical and genetic factors. [7,11] A literature search of contemporary anatomical texts, atlases and specialty radiographic texts revealed incidence rates of 7.69%, 20% and 16.6%, respectively. This lack of recognition of the OP in commonly used texts and atlases contradicts radiographic and cadaver evidence from our study.

Our study’s incidence rate of identifying the OP within the FLT from radiographs (15.12%) was consistent with other radiographic studies. (Table 1). Radiographic studies report incidence rates of 31.8%, 4.7%, 14%, 14% and 9%. [3,4,1,11,13] The reason the incidence of the OP within the FLT in the images of our study was less than cadaveric results may be due to the average age of the individuals from the radiographs (41.97 years).

Table 1 Review of OP within the FLT in radiographic and cadaveric studies.

The radiographs reviewed were from an emergency room where on average the majority of patients receiving foot radiographs are between the ages of 19-61. [9] The incidence rate might have been higher if the average age of the individuals was higher. Another study had a mean age of 51 years. [11] Two other studies only provided the range of their subjects and none were greater than 72 years. [3,4] Two other radiographic studies did not provide any information on the mean age or range. [1,13] To collect comprehensive research on the radiographic incidence of the OP within the FLT, further data is required in the age range of 60 and up.

The IR of the OP within the FLT in the cadavers (88.46%) was consistent with one cadaveric study with an incidence rate of 90%.8 This consistency may be related to similar methods of identification of the OP within the FLT. Recent cadaveric studies have reported incidence rates of 46% and 14.9%. [7,10]

One study assessed radiographic imaging from the 33 cadavers dissected, but did not look at separate populations for radiographic and cadaveric data. [7] Furthermore, that study did not report the incidence rate of the OP within the FLT when solely palpating the FLT on cadavers; their incidence rate was reported after radiographic and histologic investigation. A combined radiographic (500 individuals) and cadaveric (20 cadavers) study showed 12.3% incidence rate; this study did not separate incidence rates for radiographic and cadaveric results. [5]

In our study, the average age of the cadavers (78.1 years) is much older than the average age of the individuals in the radiographs, which may contribute to the high incidence rate of the OP within the FLT in the cadavers. Other studies that researched incidence rate of the OP within the FLT in cadavers had mean ages that were consistent with our study (81.0, 75.2 and 77.7 years). [7,8,10] However, the age range (33-97 years) was only given for one of these studies. [8]

The method of identification may also contribute to the high incidence rate of the OP within the FLT because our study palpated and dissected open the OP, but did not use histology or radiology to confirm presence of OP from cadavers.

A conflict between cadaveric and radiographic results is the fact that cadaver incidence can be based on a partially ossified OP. Therefore a partially ossified OP could be recorded as positive. In contrast, an incomplete ossification may not be obvious or present on typical radiographs. A partially ossified OP can be cartilaginous and at times cartilage cannot be recognized on ordinary (not over or under penetrated images) radiographic images. [12]

A possible factor affecting the radiographic results of our study is that we used only those patients who presented to the emergency room with foot pain. It is not common for people over age 60 to present to the emergency room with sprained ankles or fractured 5th metatarsals. The over 60 age group population present acutely with hip fractures or with gout of the great toe. There may have been different results if we had randomly chosen from the general population for OP in the FLT.

Conclusion

The clinical importance has been understated regarding the area of the os peroneum, which can be mistaken for styloid and Jones’ fractures. The radiograph IR was always over 10% regardless the age group while the cadaveric incidence rate was 88.46%. This suggests that teaching the OP in the FLT is clinically relevant because lower limb injuries are common.

References

1. Burman MS, Lapidus PW. The functional disturbance caused by the inconstant bone and sesamoids of the foot. Arch Surg 1931 22: 936.
2. Carter DR, Orr TE, Fyhrie DP, Schurman DJ. Influences of mechanical stress on prenatal and postnatal skeletal development. Clin Orthop Relat Res 1987 219: 237-250.
3. Cilli F, Akcaoglu M. The incidence of accessory bones of the foot and their clinical significance. Acta Orthop Traumatol Turc 2005 39: 243-246.
4. Coskun N, Yuksel M, Cevener M, Arican RY, Ozdemir H, Bircan O, Sindel T, Ilgi S, Sindel M. Incidence of accessory ossicles and sesamoid bones in the feet: a radiographic study of Turkish subjects. Surg Radiol Anat 2009 31: 19-24.
5. Le Minor JM. Comparative anatomy and significance of the sesamoid bone of the peroneus longus muscle (os peroneum). J Anat 1987 151: 85-99.
6. Mellado JM, Ramos A, Salvadó E, Camins A, Danús M, Saurí A. Accessory ossicles and sesamoid bones of the ankle and foot: imaging findings, clinical significance and differential diagnosis. Eur Radiol 2003 13: L164-L177.
7. Muehleman C, Williams J, Bareither ML. A radiologic and histologic study of the os peroneum: prevalence, morphology, and relationship to degenerative joint disease of the foot and ankle in a cadaveric sample. Clin Anat 2009 22: 747-754.
8. Oydele O, Maseko C, Mkasi N, Mashanyana M. High incidence of the os peroneum in a cadaver sample in Johannesburg, South Africa: possible clinical implication? Clin Anat 2006 19: 605-610.
9. Reason for Visits to Emergency Room – National Hospital Ambulatory Medical Care Survey 1998-2006. U.S. Department of Health and Human Services; Centers for Disease Control and Prevention; National Center for Health Statistics.
10. Rühli FJ, Solomon LB, Henneberg M. High prevalence of tarsal coalitions and tarsal joint variants in recent cadavers sample and its possible significance. Clin Anat 2003 16: 411-415.
11. Sarin VK, Erickson GM, Giori NJ, Bergman AG, Carter DR. Coincident development of sesamoid bones and clues to their evolution. Anat Rec 1999 257: 174-180.
12. Stranding, S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 40th ed. Philadelphia: Elsevier 2005, pg 1420.
13. Tsuruta T, Shiokawa Y, Kato A, Matsumoto T, Yamazoe Y, Oike T, Sugiyama T, Saito M. Radiological study of the accessory skeletal elements in the foot and ankle (abstract). J Jap Orthop Assoc 1981 55: 357-370.


Address correspondence to: Oregon Health & Science University
611 SW Campus Drive, Portland, OR 97239.

1 Department of Surgery, Department of Integrative Biosciences, Department of Orthopaedic Surgery & Rehabilitation, Department of Oral Maxillofacial Surgery, Oregon Health & Science University, Portland, OR.
2 Department of Integrative Biosciences, Oregon Health & Science University, Portland, OR.

© The Foot and Ankle Online Journal, 2011

Sesamoid bone interposition in the interphalangeal joint after dislocation of the hallux: A case report

by B. de Hartog, MD1 , P.F. Doorn MD, PhD2 , P.C. Rijk MD, PhD3  

The Foot and Ankle Online Journal 2 (7): 3

A 39 year-old woman injured the big toe of her right foot after a fall down the stairs. Upon examination there was a dislocation of the hallux. A plain radiograph showed a dislocation of the interphalangeal joint of the hallux and interposition of a sesamoid bone in the articular space. An attempt at closed reduction was unsuccessful, after which open reduction and excision of the sesamoid was undertaken. Dislocation of the interphalangeal joint of the hallux with interposition of a sesamoid is a rare injury. It is almost always the result of a hyperextension trauma. The clinical appearance together with a plain radiograph is in most cases sufficient for the diagnosis. Closed reduction should be attempted before open reduction is undertaken. If this is unsuccessful, it is probably due to an invaginated volar plate and sesamoid. Open reduction and removal of the sesamoid is then required followed by reduction of the volar plate plantarward. In general, the recovery is complete and without problems.

Keywords: Dislocation, hallux, interposition, sesamoids, treatment

This is an Open Access article distributed under the terms of the Creative Commons Attribution License.  It permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ©The Foot and Ankle Online Journal (www.faoj.org)

Accepted: June, 2009
Published: July, 2009

ISSN 1941-6806
doi: 10.3827/faoj.2009.0207.0003


A dislocation of the hallux with interposition of the sesamoid bone is a rare injury. [1,2,3,4,5,6] The treatment can consist of a closed reduction or an open repair. We report a 39 year-old woman with a painful hallux after a fall down the stairs. On the initial radiographs interposition in the interphalangeal joint (IPJ) of a sesamoid bone was seen. An attempt at closed reduction was unsuccessful after which the patient was treated with open reduction and excision of the sesamoid.

Case Report

A 39 year-old woman injured her right hallux after a fall down the stairs. She presented at the emergency room with an abnormal configuration of the hallux and in a significant amount of pain. On physical examination there was a dorsal dislocation of the IPJ of the great toe. Marked swelling and tenderness of the hallux was also noted.

Passive movement of the toe was very painful, active movement was not possible. The neurovascular status of the hallux was normal. A plain radiograph of the hallux showed a dislocation of the IPJ of the hallux and an entrapment of a sesamoid bone in the interphalangeal space (Figs. 1A and 1B). After local anaesthesia an attempt at closed reduction was undertaken, but was unsuccessful.

 

Figure 1A and 1B  Radiograph of the right hallux showing the enlarged joint space with the entrapment of the sesamoid in the interphalangeal space. (A) anteroposterior view. Lateral view of the interphalangeal joint. (B)

Following this, surgical removal of the sesamoid and reduction of the hallux was undertaken. Under general anaesthesia, a dorsal S-type incision was made over the IPJ. The extensor tendon was incised longitudinally and the joint capsule was opened. The sesamoid together with the volar plate were found within the articular space. The sesamoid was removed and the volar plate was reduced from the IPJ after which the hallux could be reduced. The joint capsule was closed and the skin was approximated. The patient was treated with 2 days compression bandage and normal mobilisation. The follow up was uneventful and the recovery was complete.

Discussion

Sesamoid bones of the hallux develop in the fetal period and aid the biomechanics of joint function. [7] The prevalence of interphalangeal sesamoids is approximately 13%. [8] The hallux can have one or two interphalangeal sesamoids. They are integrated in the plantar plate, which consist of the flexor hallucis longus tendon and the plantar joint capsule. [1,4,8] Dislocation of the IPJ with entrapment of a sesamoid is a rare injury and has not often been described in the literature. [1,2,3,4] This is partly due to tough soft tissue structures, which prevent hyperextension of the toe. Only when the collateral ligaments, the capsule and the volar plate are injured a dislocation of the IPJ is possible. [5] Often a hyperextension or an acute axial load type injury precedes an IPJ dislocation. [4,9] Muller described this type of injury for the first time in the Lancet in 1944. [10] At first presentation there is often tenderness of the hallux with inability of active movement. Physical examination involves palpation of the hallux, metatarsal phalangeal joint and sesamoid complex. A plain anteroposterior radiograph of the hallux is in most cases sufficient for the diagnosis. A widened interphalangeal space and interposition of a sesamoid has been observed. In some cases an overlapping of the two phalangeal bones with narrowing of the interphalangeal space can be seen. On the other hand, it has to be recognised that an epiphysial injury in adolescents can mimic a sesamoid dislocation. [2] Treatment can consist of closed reduction or surgical treatment. [2,8,11] Closed reduction, which has been successful in some cases, should be attempted by giving longitudinal traction, dorsal flexion follow by fast flexion in the IPJ. However, in several case reports it has been demonstrated that closed reduction is not successful. In these cases open reduction and reflexion or removal of the interphalangeal sesamoid and/or volar plate plantarward is mandatory. Although removal might have a negative effect on the biomechanics of the hallux, in most cases a complete recovery is made. [8]

References

1. Eibel P: Dislocation of the interphalangeal joint of the big toe with interposition of a sesamoid bone. J Bone Joint Surg 36A (4): 880 – 882, 1954.
2. Dave D, Jayaraj VP, James SE: Intra-articular sesamoid dislocation of the interphalangeal joint of the great toe. Injury 24 (3): 198 – 199, 1993
3. Berger JL, LeGeyt MT, Ghobadi R: Incarcerated subhallucal sesamoid of the great toe: Irreducible dislocation of the great toe by an accessory sesamoid bone. Am J Orthop 26: 116 – 228, 1997.
4. Sorene E.D, Regev G: Complex dislocation with double sesamoid entrapment of the interphalangeal joint of the hallux. Foot Ankle Surg 46 (6): 413 – 416, 2006.
5. Miki T, Yamamuro T, Kitai T: An irreducible dislocation of the great toe. Report of two cases and review of the literature. Clin Orthop Relat Res 230 : 200 – 206, 1988
6. Kursunuglu S, Resnick D, Goergen T: Traumatic dislocation with sesamoid entrapment in the interphalangeal joint of the great toe. J Trauma 27 : 959 – 961, 1987.
7. Rodeo SA, Warren RF, O’Brien SJ, Pavlov H: Diastasis of bipartite sesamoids of the first metatarsal phalangeal joint. Foot Ankle 14: 425 – 434, 1993.
8. Davies MB Abdlslam K, Gibson RJ: Interphalangeal sesamoid bones of the great toe: An anatomic variant demanding careful scrutiny on radiographs. Clinical anatomy 16: 520 – 521, 2003.
9. Nelson TL, Uggen W: Irreducible dorsal dislocation of the interphalangeal joint of the great toe. Clin Orthop Relat Res 157: 110 – 112, 1981.
10. Müller G.M: Dislocation of sesamoid of Hallux. Lancet 1: 789, 1944.
11. Szucs R, Hurwitz J: Traumatic subluxation of the interphalangeal joint of the hallux with interposition of the sesamoid bone. Am J Roentgenol 152 : 652 – 653, 1989.


Address correspondence to: P.C. Rijk, P.O. Box 888, 8901 BR Leeuwarden, The Netherlands, Tel: 0031-582867282, Fax: 0031-582867611
Email: P.Rijk@znb.nl

1 ,2,3  Bas de Hartog M.D, Peter F. Doorn M.D, PhD, Paul C. Rijk M.D, PhD
Department of Orthopaedic Surgery, Medical Centre Leeuwarden, Leeuwarden, The Netherlands.

© The Foot and Ankle Online Journal, 2009