BIYANI AND KOTWAL : BILATERAL DOUBLE PATELLAE
knees revealed double layered patellae, larger and thicker anterior layers in close relationship with bipartite smaller and thick posterior layers (Fig 1). Lateral films in flexion and extension of the knees did not show movement of one layer on the other. Tibiofemoral epiphysis were not involved. Axial skeleton was normal. Hip deformity was corrected by traction and stretching programme. Gait could be improved in this way. Lateral subluxation of patella did not warrant surgery at this time. Double layered patella is an uncommon accompaniment of multiple epiphyseal dysplasia and dwarfism. Lodes 5 had erroneously suggested that these cases represent Morquio disease. Subsequent studies 4 have shown that this disorder is a distinct entity. Patellar abnormality may not be apparent before patella has significantly ossified. Habitual lateral subluxation of patella in patients with multiple epiphyseal dysplasia should arouse strong suspicion of double layered patellae. Lateral radiographs of the knee should be routinely ineluded in the skeletal survey of epiphyeal dysplasia. One or both layers may be multipartite. Dahners et aF noted synovial joint lined by hyaline cartilage in their case and the two layers of patella glided over each other during movement of the knee joint. Lateral subluxation of the patella often requires surgery for patellar tendon realignment.
A. Biyani and P.P. Kotwal, Department of Orthopaedics All India Institute of Medical Sciences New Delhi 110 029.
REV~NCES 1. Beaupore A, Nausib PAD. One dysplasia
2.
3. 4.
5.
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and four patellae (Proceedings). J Bone Joint Surg. 1982; 64B : 261-262. 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. Ficat P, Hungerford D. Disorders of the Patellofemoml joint. Baltimore : Williams and Wilkins, 1977 : 58-62. Hodkinson HM. Double patellae in multiple epiphyseal dysplasia. J Bone Joint Surg 1%2; 44B : 569-572. Lodes R. Familiares Vorkommen habitu, ellar bilateraler Luxation zweigeteilter Kniescheiben hie Chondrodystrophic. Z Orthop 1949; 78 : 506-523.
Down Syndrome in Dubai Sir - Dubai known as the pearl of the Gulf is one of the seven Emirates in the United Arab Emirates (UAE). In Dubai there are four major hospitals which come under the Department of Health and Medical Sciences ( D O H M S ) in the Government of Dubai. Over a three year period from 1987 to 1989, 1630 cultures were received for chromosomal analysis. Of this 56% were in the pediatric age group and referred as patients with multiple congenital abnormalities, the remaining cases were patients affected with habitual abortions or infertility (Table 1). In the pediatric age group 11.2% of the cases were found to be affected with a gross chromosomal aberration ranging from deletions, duplications, inversions,
276
THE INDIAN JOURNAL OF PEDIATRICS
TABLE2. Incidence of Down syndrome at DOH & MS
TABLE1. Cytogenetic Analysis at DOH & MS Year
No. of Chromosomal chromo- aberrations sorlaal analyses No. %
Down syndrome
No.
%
1987
460
62
13.5
35
7.6
1988
553
52
9.4
30
5.4
1989
617
69
11.18
40
6.5
Total
1630
183
11.23 105
6.4
D
ring chromosomes and various trisomies. The largest group (6.4%) of chromosomal aberrations was that of trisomy 21. Of the 105 registered cases of Down syndrome, 85 patients have been born in DOHMS over these three years (Table 2). Seven patients were found to be cases of 13/21 translocation. None of the parents were found to be translocation carriers. There is an ongoing program, both by maternal serum AFP screening and amniotic fluid cultures, to prenatally detect cases of Down syndrome. Due to the
Vol. 57, No. 2
Year
Total no.of livebirths
Total no. of Down syndrome cases
1987
10,183
21 (9F, 12M) 1 in 485
1988
11,615
23 (llF, 12M) 1 in 505
1989
12,640
27 (17F, 10M) 1 in 485
Total
34,438
71
Incidence DOHMS
1 in 485
cosmopolitan nature of the population it is difficult to categorize various ethnic groups for any meaningful analysis. The problem of Down syndrome in Dubai is an enormous one. T o our knowledge this is the first report from the UAE.
S. EI-Kalla and A.R. Mathews Genetic Unit, Pediatric Department, Department of Hea/th and Medica/ Services, P.O. Box 9115, Dubai, U.A.E.