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Case Report
Open Access Peer-reviewed

Multipartite Patella: Diagnosis Trap

A. LAGDID , M. Boufettal, RA. Bassir, M. KHARMAZ, MO Lamrani, M. Ouadghiri, A. El Bardouni, M. MAHFOUD, M.S. BERRADA
American Journal of Medical Case Reports. 2018, 6(6), 114-116. DOI: 10.12691/ajmcr-6-6-4
Published online: July 21, 2018

Abstract

Our study reports a case of a multipartite patella that was initially diagnosed as a patellar fracture in a traumatic context but in view of the smooth, regular and dense appearance of the fracture traits, a comparative radiological evaluation of the other knee was necessary, which precluded the diagnosis of fracture in favor of a multipartite patella with knee sprain treated by immobilization and treatment anti-inflammatory with a good evolution, hence the interests of performing a comparative radiological assessment of the contralateral knee in front of any patellar fracture. The multipartite patella is recognized as a developmental anomaly of ossification. Most of them are asymptomatic and are discovered incidentally. The multipartite patella is sometimes misdiagnosed as a patellar fracture, because the x-ray images of both these conditions may appear very similar.

1. Introduction

The patella is located on the anterior part of the knee joint and is the largest sesamoid bone in the human body 1.

The major ossification center appears at the age of 4-6, and accessory ossification centers appear around the age of 12 2. Twenty-three percent of children have two to three accessory ossification centers, and the main center fuses with accessories during childhood and adolescence.

However, in 2% of children, the centers do not coalesce 3, 4. This lack of fusion can cause a bipartite patella, a tripartite patella or a multipartite patella.

It should be noted that the multipartite patella can give the appearance of a comminuted fracture 5.

2. Case Report

This is a 32-year-old man who presented to the emergency department for a closed trauma of the right knee with pain and total functional impotence. The examination found an intra-articular effusion with pain to mobilization and extensive bruising on the anterior aspect of the knee.

Radiographic evaluation of face and profile of the knee demonstrated a multi-fragmented aspect of the right patella initially orienting the diagnosis to a comminuted fracture of the patella (Figure 1).

However, in view of the smooth, regular and dense aspect of the fracture traits, a comparative radiological assessment of the other knee was necessary (Figure 2), which ruled out the diagnosis of a fracture in favor of a multipartite patella with sprained knee that was treated by immobilization and anti-inflammatory treatment with a good evolution. This radiological assessment was completed by a CT scan of both knees with 3D reconstruction (Figure 3); not for a diagnostic purpose but especially for an iconographic complement; and which showed the presence of three ossicles of oval shape (not ossified to the main body of the patella) measuring approximately 1 to 2.5 cm diameter. The ossicles had opposite, smooth, regular surfaces with condensation of cortical margins. The ossicles were located on the supero-lateral edge of the patella.

3. Discussion

The supero-lateral angle of the patella is the privileged site for the development of one of the multipartite forms. It has been speculated that this may be due to the scarcity of vascular supply during developmental stages. This phenomenon is usually bilaterally symmetrical (80%) 6 and asymptomatic.

Some characteristics differentiate a multipartite patella from a fracture and which are 7:

- The site that is usually on the super-lateral part of the patella;

- Bilateral and symmetrical character;

- Generally asymptomatic abnormality;

- The curved, dense and smooth appearance of the cortical margins of the patella.

On the other hand, fracture surfaces are usually irregular, unilateral, have no dense margins and are often related to a traumatic episode 7.

Frequently, fracture fragments move from their host sites 7.

Practitioners should also be prepared to differentiate Larsen-Johansson's disease, which is an osteochondritis from an infrequent accessory ossification center at the lower edge of the patella 8.

There are three main factors that could prevent these ossification centers from fusing. One is the abnormal development of the ossification center of the patella. When ossification in the center appears initially, it is often multifocal and fuses rapidly. A granular or irregular margin may appear in the process of expansion of the ossification center in the cartilage 2. This irregular margin may play an important role in the abnormal development of the ossification center 9. The second factor is the interposed tissue that is observed between the accessory fragment and the main body of the patella. The predominant composition of the interposed tissue is fibrous tissue and fibrocartilage 10, 11. Degeneration and necrosis of the fibrocartilage of the interposed tissue was observed in patients with painful bipartite patella 10 and also an absence of blood vessels in the central region of the interposed tissue was found in all patients. Scapinelli 12 also observed a lack of arterial penetration into the osteochondral fragment. This can decrease the regenerative capacity of the cartilaginous tissues and prevent the accessory fragment from combining with the main body of the patella. The third factor is the tensile forces on the separated fragment. Batten and Menelaus 13 have assumed that quadriceps mechanism traction can lead to separation of fragments, and that continuous traction forces on the accessory fragment can also prevent union.

In conclusion, we diagnosed the patient with a multipartite kneecap with supero-lateral localization instead of a patellar fracture. The multipartite patella is a normal anatomical variant, not a human body injury. Hence the interests of performing a comparative radiological assessment of the contralateral knee in front of any patellar fracture.

References

[1]  Oohashi Y. Developmental anomaly of ossification type patella partita. Knee Surg Sports Traumatol Arthrosc 2015; 23(4): 1071-6.
In article      View Article  PubMed
 
[2]  Ogden JA. Radiology of postnatal skeletal development. X. Patella and tibial tuberosity. Skeletal Radiol 1984; 11(4): 246-57.
In article      View Article  PubMed
 
[3]  Okuno H, Sugita T, Kawamata T, Ohnuma M, Yamada N, Yoshizumi Y. Traumatic separation of a type I bipartite patella: a report of four knees. Clin Orthop 2004; 420(420): 257-60.
In article      View Article
 
[4]  Ireland ML, Chang JL. Acute fracture bipartite patella: case report and literature review. Med Sci Sports Exerc 1995; 27(3): 299-302.
In article      View Article  PubMed
 
[5]  Bowerman JW. Radiology and injury in sport. New York: Appleton Century Crofts, 1977: 129.
In article      View Article
 
[6]  Paul LW, Juhl P. The essentials of roentgen interpretation. 4th ed. New York: Harper and Row, 1976: 70.
In article      
 
[7]  James R Grilliot, BSC, BA, B App SC, DACBR*. Patellar anomaly - a case review of quadripartite patella.The Journal of the CCA/Volume 29 No. 3/September 1985.
In article      View Article
 
[8]  Schultz RJ. The language of fractures. St. Louis: Dreiger Pub Co., 1983: 112.
In article      PubMed
 
[9]  Jingyuan Ma,1 Ph.D.; Fang Shi,1 M.D.; Chongya Huang,1 Ph.D.; and Shanzhi Gu,1 Ph.D. Forensic Identification of Bipartite Patella Misdiagnosed as Patella Fracture. J Forensic Sci, July 2017, Vol. 62, No. 4.
In article      View Article
 
[10]  Oohashi Y, Noriki S, Koshino T, Fukuda M. Histopathological abnormalities in painful bipartite patellae in adolescents. Knee 2006; 13 (3): 189-93.
In article      View Article  PubMed
 
[11]  Atesok K, Doral MN, Lowe J, Finsterbush A. Symptomatic bipartite patella: treatment alternatives. J Am Acad Orthop Surg 2008; 16(8): 455-61.
In article      View Article  PubMed
 
[12]  Scapinelli R. Blood supply of the human patella. Its relation to ischaemic necrosis after fracture. J Bone Joint Surg Br 1967; 49(3): 563-70.
In article      View Article  PubMed
 
[13]  Rosenthal RK, Levine DB. Fragmentation of the distal pole of the patella in spastic cerebral palsy. J Bone Joint Surg Am 1977; 59(7): 934-9.
In article      View Article
 

Published with license by Science and Education Publishing, Copyright © 2018 A. LAGDID, M. Boufettal, RA. Bassir, M. KHARMAZ, MO Lamrani, M. Ouadghiri, A. El Bardouni, M. MAHFOUD and M.S. BERRADA

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

Cite this article:

Normal Style
A. LAGDID, M. Boufettal, RA. Bassir, M. KHARMAZ, MO Lamrani, M. Ouadghiri, A. El Bardouni, M. MAHFOUD, M.S. BERRADA. Multipartite Patella: Diagnosis Trap. American Journal of Medical Case Reports. Vol. 6, No. 6, 2018, pp 114-116. http://pubs.sciepub.com/ajmcr/6/6/4
MLA Style
LAGDID, A., et al. "Multipartite Patella: Diagnosis Trap." American Journal of Medical Case Reports 6.6 (2018): 114-116.
APA Style
LAGDID, A. , Boufettal, M. , Bassir, R. , KHARMAZ, M. , Lamrani, M. , Ouadghiri, M. , Bardouni, A. E. , MAHFOUD, M. , & BERRADA, M. (2018). Multipartite Patella: Diagnosis Trap. American Journal of Medical Case Reports, 6(6), 114-116.
Chicago Style
LAGDID, A., M. Boufettal, RA. Bassir, M. KHARMAZ, MO Lamrani, M. Ouadghiri, A. El Bardouni, M. MAHFOUD, and M.S. BERRADA. "Multipartite Patella: Diagnosis Trap." American Journal of Medical Case Reports 6, no. 6 (2018): 114-116.
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[1]  Oohashi Y. Developmental anomaly of ossification type patella partita. Knee Surg Sports Traumatol Arthrosc 2015; 23(4): 1071-6.
In article      View Article  PubMed
 
[2]  Ogden JA. Radiology of postnatal skeletal development. X. Patella and tibial tuberosity. Skeletal Radiol 1984; 11(4): 246-57.
In article      View Article  PubMed
 
[3]  Okuno H, Sugita T, Kawamata T, Ohnuma M, Yamada N, Yoshizumi Y. Traumatic separation of a type I bipartite patella: a report of four knees. Clin Orthop 2004; 420(420): 257-60.
In article      View Article
 
[4]  Ireland ML, Chang JL. Acute fracture bipartite patella: case report and literature review. Med Sci Sports Exerc 1995; 27(3): 299-302.
In article      View Article  PubMed
 
[5]  Bowerman JW. Radiology and injury in sport. New York: Appleton Century Crofts, 1977: 129.
In article      View Article
 
[6]  Paul LW, Juhl P. The essentials of roentgen interpretation. 4th ed. New York: Harper and Row, 1976: 70.
In article      
 
[7]  James R Grilliot, BSC, BA, B App SC, DACBR*. Patellar anomaly - a case review of quadripartite patella.The Journal of the CCA/Volume 29 No. 3/September 1985.
In article      View Article
 
[8]  Schultz RJ. The language of fractures. St. Louis: Dreiger Pub Co., 1983: 112.
In article      PubMed
 
[9]  Jingyuan Ma,1 Ph.D.; Fang Shi,1 M.D.; Chongya Huang,1 Ph.D.; and Shanzhi Gu,1 Ph.D. Forensic Identification of Bipartite Patella Misdiagnosed as Patella Fracture. J Forensic Sci, July 2017, Vol. 62, No. 4.
In article      View Article
 
[10]  Oohashi Y, Noriki S, Koshino T, Fukuda M. Histopathological abnormalities in painful bipartite patellae in adolescents. Knee 2006; 13 (3): 189-93.
In article      View Article  PubMed
 
[11]  Atesok K, Doral MN, Lowe J, Finsterbush A. Symptomatic bipartite patella: treatment alternatives. J Am Acad Orthop Surg 2008; 16(8): 455-61.
In article      View Article  PubMed
 
[12]  Scapinelli R. Blood supply of the human patella. Its relation to ischaemic necrosis after fracture. J Bone Joint Surg Br 1967; 49(3): 563-70.
In article      View Article  PubMed
 
[13]  Rosenthal RK, Levine DB. Fragmentation of the distal pole of the patella in spastic cerebral palsy. J Bone Joint Surg Am 1977; 59(7): 934-9.
In article      View Article