Trochlear dysplasia and patellar instability in patients with Down syndrome

Eleven knees with stable patellae and thirteen with unstable patellae in patients with Down syndrome were compared. Radiographs were produced to evaluate patellar height, trochlear angle and femoropatellar congruence angle.

RESULTS:

The prevalence ratio for a high patella between the unstable and the stable patients was 1.01 using the Insall-Salvati index and 0.68 using the Caton-Deschamps index. For an abnormal congruence angle, the prevalence ratio was 2.04. An increased congruence angle was only found in four cases, all presenting instability.

CONCLUSIONS:

Trochlear dysplasia was only found in cases of instability. The trochlear groove angle and the femoropatellar congruence angle correlated with the presence of patellar instability.

Patellar dislocation; Down syndrome; Knee

Number	Sex	Date of birth	Age (a)	Weight (kg)	Height (m)	BMI
1	M	01/10/95	14	52	1.54	21.9
2	F	7/25/00	9	26	1.26	16.4
3	M	5/25/99	10	31	1.4	15.8
4	M	5/9/00	9	44	1.32	25.2
5	M	7/10/92	17	90	1.6	35.2
6	F	4/11/89	21	52	1.52	22.5
7	F	4/8/99	11	45	1.48	20.6
8	M	7/7/87	22	59	1.53	25.2
9	F	9/19/87	22	65	1.4	33.2
10	M	4/29/74	36	74	1.73	24.7
11	F	11/3/03	6	23	1.12	18.3
12	F	5/5/90	20	68	1.4	34.7
Mean			16.4	52.4	1.44	24.5
Standard deviation			8.4	20.2	0.16	6.75
Minimum			6	23	1.12	15.8
Maximum			36	90	1.73	35.2

Radiographic criterion	Clinical criterion
	Stable	Unstable
High patella (Caton–Deschamps)	5	4
Trochlear groove >150°	0	4
Patellar congruence >11°	4	9

Sociedade Brasileira de Ortopedia e Traumatologia Al. Lorena, 427 14º andar, 01424-000 São Paulo - SP - Brasil, Tel.: 55 11 2137-5400 - São Paulo - SP - Brazil
E-mail: rbo@sbot.org.br

Acompanhe os números deste periódico no seu leitor de RSS

[1] * Corresponding author. E-mail: demange@me.com (M.K. Demange).

Brasil

Brasil

Trochlear dysplasia and patellar instability in patients with Down syndrome☆ ☆ Work developed in the Knee Group, Institute of Orthopedics and Traumatology, Hospital das Clínicas, School of Medicine, Universidade de São Paulo (HC/FMUSP), São Paulo, SP, Brazil.

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSIONS:

Trochlear dysplasia and patellar instability in patients with Down syndrome^☆ ☆ Work developed in the Knee Group, Institute of Orthopedics and Traumatology, Hospital das Clínicas, School of Medicine, Universidade de São Paulo (HC/FMUSP), São Paulo, SP, Brazil.