DOI: 10.1148/radiol.2393032020
(Radiology 2006;239:911-913.)
© RSNA, 2006
Case 95:
Fracture of Double-layered Patella in Multiple Epiphyseal Dysplasia1
Joel D. Rubenstein, MD, FRCPC and
Monique S. Christakis, MD, FRCPC
1 From the Department of Medical Imaging, Sunnybrook and Women's College Health Sciences Center, 2075 Bayview Ave, Toronto, ON, Canada M4N 3M5. Received December 27, 2003; revision requested February 27, 2004; revision received March 15; final version accepted April 16.
Correspondence: Address correspondence to J.D.R. (e-mail: joel.rubenstein{at}sw.ca).
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History
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A 22-year-old man who previously had undergone bilateral hip surgery presented with left knee pain after a fall. Physical examination revealed a flexed knee, with pain and swelling along the anterior aspect of the knee. Radiographs of the knee were obtained. Magnetic resonance (MR) imaging of the knee was performed subsequently.
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Imaging Findings
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Radiography (Fig 1) revealed that the left knee was flexed, with abnormally shaped femoral condyles, and that a double-layered patella (DLP) was present. MR imaging (Fig 2) helped confirm both the abnormal contour of the femoral condyles with cartilage loss and the presence of a fracture in the anterior segment of the DLP.
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Figure 1a: (a) Anterposterior radiograph shows the knee is flexed with flattening of the femoral condyles, particularly the medial condyle. (b) Lateral radiograph shows abnormal femoral condyles and two patellae. A = anterior, P = posterior. (c) Tangential patellar radiograph shows two patellae; note the midline fracture (arrow) in the anterior patella.
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Figure 1b: (a) Anterposterior radiograph shows the knee is flexed with flattening of the femoral condyles, particularly the medial condyle. (b) Lateral radiograph shows abnormal femoral condyles and two patellae. A = anterior, P = posterior. (c) Tangential patellar radiograph shows two patellae; note the midline fracture (arrow) in the anterior patella.
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Figure 1c: (a) Anterposterior radiograph shows the knee is flexed with flattening of the femoral condyles, particularly the medial condyle. (b) Lateral radiograph shows abnormal femoral condyles and two patellae. A = anterior, P = posterior. (c) Tangential patellar radiograph shows two patellae; note the midline fracture (arrow) in the anterior patella.
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Figure 2a: (a) Coronal fat-suppressed intermediate-weighted (repetition time msec/echo time msec, 2867/21) MR image shows flattening of the femoral condyles with cartilage loss and joint space narrowing. (b) Sagittal intermediate-weighted (2100/21) MR image enabled confirmation of the morphologic changes apparent in a. (c) Coronal fat-suppressed intermediate-weighted (2867/21) MR image shows a fracture (arrow) in the anterior (A) patellar segment with associated marrow edema; no edema is seen in the posterior (P) patellar segment, which is not fractured.
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Figure 2b: (a) Coronal fat-suppressed intermediate-weighted (repetition time msec/echo time msec, 2867/21) MR image shows flattening of the femoral condyles with cartilage loss and joint space narrowing. (b) Sagittal intermediate-weighted (2100/21) MR image enabled confirmation of the morphologic changes apparent in a. (c) Coronal fat-suppressed intermediate-weighted (2867/21) MR image shows a fracture (arrow) in the anterior (A) patellar segment with associated marrow edema; no edema is seen in the posterior (P) patellar segment, which is not fractured.
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Figure 2c: (a) Coronal fat-suppressed intermediate-weighted (repetition time msec/echo time msec, 2867/21) MR image shows flattening of the femoral condyles with cartilage loss and joint space narrowing. (b) Sagittal intermediate-weighted (2100/21) MR image enabled confirmation of the morphologic changes apparent in a. (c) Coronal fat-suppressed intermediate-weighted (2867/21) MR image shows a fracture (arrow) in the anterior (A) patellar segment with associated marrow edema; no edema is seen in the posterior (P) patellar segment, which is not fractured.
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Discussion
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Multiple epiphyseal dysplasia (MED) is a type of chondrodysplasia caused by a disturbance of endochondral ossification associated with hypoplasia of the epiphyseal cartilage of tubular bones; the vertebrae are essentially normal (1). Epiphyseal ossification alterations are bilateral, symmetrical, and more marked in the lower extremities.
At birth, clinical and radiographic features of MED are absent. The clinical presentation is variable and may occur either in childhood, with evidence of a waddling gait and difficulty running and climbing stairs, or in adolescence, with joint pain or a limp due to premature osteoarthritis (2). Individuals with MED are of short stature, but the growth retardation associated with MED is mild relative to that associated with other dysplasias. MED affects individuals equally, regardless of sex; intelligence is normal. The hips and knees tend to be the most severely affected articulations; however, the ankles, shoulders, elbows, and wrists are also involved.
Radiographic features depend on the age of the patient at the time of presentation (3,4). Early in childhood, the epiphyseal growth centers are delayed and ultimately show an irregular fragmented appearance when they do begin to ossify. As children with MED age, a coxa vara deformity develops and the incidence of slipped capital femoral epiphyses increases. Ultimately, premature osteoarthritic changes become apparent, particularly in the hips and knees.
Historically, MED has been divided into congenital and tardive forms of disease (5); however, recent advances in molecular genetics and gene mapping have shown that MED is a heterogeneous skeletal dysplasia that is more appropriately classified on the basis of gene mutations and their products (1). These mutations are found in genes responsible for coding cartilage oligomeric matrix protein, type IX collagen, and matrilin-3 (2,6–9).
MED with autosomal dominant transmission was described first and has been divided into two types: Type I MED is caused by a mutation in gene coding for cartilage oligomeric matrix protein (10). Type II MED is produced by a mutation in the gene coding for the 
2 polypeptide chain of type IX collagen (2).
DLP, which represents one of five types of partite patella (11), has been previously described in association with MED (12,13) and is caused by a coronal septum that divides the patella into anterior and posterior segments (11). Further investigation shows that MED associated with DLP is caused by mutations in the diastrophic dysplasia sulfate transporter gene and that the transmission is autosomal recessive (14). Clubfoot deformity, brachydactyly, scoliosis, cleft palate, joint contracture, and patellar subluxation or dislocation are additional features that may be associated with recessive MED (15,16).
A DLP may cause a variety of clinical problems, including clicking or locking of the knee and patellar dislocation. As a result, a variety of surgical treatments, including patellectomy of both segments (11), resection of the posterior segment (12), and surgical fusion of the two patellar segments (17), have been attempted.
According to Makitie et al (14), a DLP—when present—appears to be specific for recessive MED and distinguishes recessive MED from the autosomal dominant types of MED. In terms of differential diagnosis, it has been proposed that identification of a DLP is highly diagnostic, if not pathognomonic, for MED because DLP has not been described in association with any other skeletal dysplasia or as an isolated abnormality (4).
In summary, MED is a heterogeneous group of skeletal dysplasias that may show an autosomal dominant or recessive pattern of inheritance; a DLP, when present, is considered diagnostic for recessive MED.
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FOOTNOTES
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| Part one of this case appeared 4 months previously and may contain larger images.
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References
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- Brown RR, Monsell F. Understanding the skeletal dysplasias. Curr Orthop 2003;17:44–55.[CrossRef]
- Briggs MD, Hoffman SM, King LM, et al. Pseudoachondroplasia and multiple epiphyseal dysplasia due to mutations in the cartilage oligomeric matrix protein gene. Nat Genet 1995;10:330–336.[CrossRef][Medline]
- Mansoor IA. Dysplasia epiphysealis multiplex. Clin Orthop Relat Res 1970;72:287–292.[Medline]
- Goldman AB. Collagen disease, epiphyseal dysplasias, and related conditions. In: Resnick D, ed. Diagnosis of bone and joint disorders. Philadelphia, Pa: Saunders, 2002; 4421–4429.
- Greenfield GB. Radiology of bone diseases. Philadelphia, Pa: Lippincott, 1975; 198–202.
- Muragaki Y, Mariman EC, van Beersum SE, et al. A mutation in the gene encoding the alpha 2 chain of the fibril-associated collagen IX, COL9A2, causes multiple epiphyseal dysplasia (EDM2). Nat Genet 1996;12:103–105.[CrossRef][Medline]
- Paassilta P, Lohiniva J, Annunen S, et al. COL9A3: a third locus for multiple epiphyseal dysplasia. Am J Hum Genet 1999;64:1036–1044.[CrossRef][Medline]
- Chapman KL, Mortier GR, Chapman K, Loughlin J, Grant ME, Briggs MD. Mutations in the region encoding the von Willebrand factor A domain of matrilin-3 are associated with multiple epiphyseal dysplasia. Nat Genet 2001;28:393–396.[CrossRef][Medline]
- Czarny-Ratajczak M, Lohiniva J, Rogala P, et al. A mutation in COL9A1 causes multiple epiphyseal dysplasia: further evidence for locus heterogeneity. Am J Hum Genet 2001;69:969–980.[CrossRef][Medline]
- Dietz FR, Mathews KD. Update on the genetic bases of disorders with orthopaedic manifestations. J Bone Joint Surg Am 1996;78:1583–1598.[Free Full Text]
- Sheffield EG. Double-layered patella in multiple epiphyseal dysplasia: a valuable clue in the diagnosis. J Pediatr Orthop 1998;18:123–128.[CrossRef][Medline]
- Dahners LE, Francisco WD, Halleran WJ. Findings at arthrotomy in a case of double layered patellae associated with multiple epiphyseal dysplasia. J Pediatr Orthop 1982;2:67–70.[Medline]
- Hodkinson HM. Double patellae in multiple epiphyseal dysplasia. J Bone Joint Surg Br 1962;44:569–572.
- Makitie O, Savarirayan R, Bonafe L, et al. Autosomal recessive multiple epiphyseal dysplasia with homozygosity for c653s in the DTDST gene: double-layer patella as a reliable sign. Am J Med Genet A 2003;122:187–192.[Medline]
- Superti-Furga A, Neumann L, Riebel T, et al. Recessively inherited multiple epiphyseal dysplasia with normal stature, club foot, and double layered patella caused by a DTDST mutation. J Med Genet 1999;36:621–624.[Abstract/Free Full Text]
- Ballhausen D, Bonafe L, Terhal P, et al. Recessive multiple epiphyseal dysplasia (rMED): phenotype delineation in eighteen homozygotes for DTDST mutation R279W. J Med Genet 2003;40:65–71.[Free Full Text]
- Gardner J, Woods D, Williamson D. Management of double-layered patellae by compression screw fixation. J Pediatr Orthop B 1999;8:39–41.[Medline]
Congratulations to the 60 individuals who submitted the most likely diagnosis (fracture of double-layered patella in multiple epiphyseal dysplasia) for Diagnosis Please, Case 95. The names and locations of the individuals, as submitted, are as follows:
Individual responses
- Gholamali Afshang, MD, Tinley Park, Ill
- Okan Akinci, MD, Istanbul, Turkey
- Matthew Allen, La Grande, Ore
- Canan Altay, MD, Izmir, Turkey
- Albert J. Alter, Madison, Wis
- Javier Arnaiz, MD, Santander, Spain
- Gregory J. Balmforth, MD, Tucson, Ariz
- Eric L. Bressler, MD, Minnetonka, Minn
- Ghislain Brousseau, MD, Charlesbourg, Quebec, Canada
- Douglas C. Brown, MD, Virginia Beach, Va
- Y. S. Cordoliani, MD, Paris, France
- Marc G. de Baets, MD, Lugano, Switzerland
- J. F. K. de Villiers, Gisborne, New Zealand
- Mustafa Kemal Demir, MD, Istanbul, Turkey
- John Michael Ellis, MD, Clinton, NY
- Seyed Emamian, MD, PhD, Rockville, Md
- Bill Gallmann, MD, Shreveport, La
- Douglas Gardner, MD, Windsor, Ontario, Canada
- William Gawman, Waterloo, Ontario, Canada
- Yves Goël, MD, Lausanne, Switzerland
- Mark Goldshein, MD, Andover, Mass
- Francisco J. Gonzalez, MD, Cantabria, Spain
- Rajapandian Ilangovan, MD, FRCR, London, United Kingdom
- Jacobo Kirsch, MD, Cleveland, Ohio
- Mario Laguna, West Allis, Wis
- Donald R. Lewis, Jr, MD, Huntington, WV
- David A. Lisle, Brisbane, Australia
- Michael B. Martin, MD, Austin, Tex
- Walter P. Maynard, MD, Inglewood, Calif
- Koen Mermuys, MD, Heverlee, Belgium
- Jonathan Meyer, MD, Chicago, Ill
- Stephen F. Miller, MD, Toronto, Ontario, Canada
- Docteur Thomas Moser, Strasbourg, France
- Tammam Nehme, East Wenatchee, Wash
- Edward S. Oh, MD, Tucson, Ariz
- Sanford M. Ornstein, MD, Phoenix, Ariz
- Dr Klaus Orth, Aachen, Germany
- Ann B. Owen, MD, Murfreesboro, Tenn
- Narendrakumar P. Patel, MD, Newburgh, NY
- Hilton W. Pittman, Pensacola, Fla
- Dr Pieter M. Pretorius, Oxford, United Kingdom
- Shawn P. Quillin, MD, Charlotte, NC
- Prashant Raghavan, MD, Charlottesville, Va
- Mathieu H. Rodallec, Paris, France
- Javier Rodríguez Lucero, MD, Rosario, Argentina
- Steven Schepers, Herent, Belgium
- Steven M. Schultz, MD, Fort Worth, Tex
- Anthony J. Scuderi, MD, Johnstown, Pa
- Dr Vinod A. Shenoy, Norwich, United Kingdom
- Alberto Simoncini, Buenos Aires, Argentina
- Stephen Horatio Slawson, MD, Joplin, Mo
- Amit Suri, MD, Kings Lynn, Norfolk, United Kingdom
- Rogério Teles de Melo, Belo Horizonte, Brazil
- William C. Torreggiani, Dublin, Ireland
- Dr Muhammad Umar Islam, FRCR, Sydney, Nova Scotia, Canada
- Piet K. Vanhoenacker, MD, Aalst, Belgium
- Joan C. (Kai) Vilanova, MD, Girona, Spain
- Christopher Vittore, MD, Rockford, Ill
- Joe Yut, Olathe, Kan
- Yu Zhang, San Francisco, Calif
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History
Imaging Findings
