Volume 4 | Issue 1 | January-June 2018 | Page: 07-11 | Sandeep Vijayan, Dhiren Ganjwala, Hitesh Shah
Authors: Sandeep Vijayan, Dhiren Ganjwala , Hitesh Shah
Department of Orthopaedics, Paediatric Orthopaedic Service, Kasturba Medical College, Manipal, Karnataka,
 Paediatric Orthopaedic Service, Ganjwala Orthopaedic Hospital, Ahmedabad, Gujarat, India.
Address of Correspondence
Dr. Hitesh Shah,
Department of Orthopaedics, Kasturba Medical College, Manipal – 576 104, Karnataka, India.
Introduction: Acetabular index (AI) is a commonly used quantitative measurement of acetabular inclination in plain radiographs. Repeated measurements of this index are used to determine dysplasia in children and for decision making about surgical management. Persistent acetabular dysplasia may be an indication for performing an acetabuloplasty. AI is commonly measured between the Hilgenreiner’s line (line that connects both triradiate cartilages) and the line joining lateral most ossified margin of the acetabulum and triradiate cartilage. Two different methods for measurement of AI with two different medial reference points at the triradiate cartilage have appeared in the literature. Aim: The specific aim of the study was to investigate the difference between AI measurements with two different methods and report on intraobserver and interobserver reliability of both the methods. Materials and Methods: Ninety-eight children with developmental dysplasia of the hip (DDH) (treated and untreated), younger than 9 years, were included in the study. Anteroposterior radiographs of the pelvis having acceptable pelvic rotation and pelvic tilt were included in the study. AI was measured using two different reference points for the affected and normal sides. AI was measured twice at 1-month interval by two investigators. The difference between the two measurement techniques was compared by the paired “t” test. Pearson’s correlation coefficient was calculated to test associations between the two measurement techniques. Results: The reproducibility of measurements of both the techniques was found satisfactory [intraclass correlation (ICC)-0.90 and 0.87]. Statistically significant difference (P value < 0.001) (5.7° for affected and 5.3° for normal side) between the indices measured by two techniques was noted. This difference was noted for all age groups. Significant positive correlations between both the techniques were noted in normal as well as dysplastic hips. Conclusion: Acetabular indices measured with two different medial points gave significantly different values. All subsequent assessment should be consistently carried out by the same method.
Keywords: Acetabular index, Acetabuloplasty, Developmental dysplasia of hip, Medial reference point
1. Weinstein SL. Natural history of congenital hip dislocation (CDH) and hip dysplasia. Clin Orthop Relat Res 1987;(225):62-76.
2. Tonnis D. Normal values of the hip joint for the evaluation of X-rays in children and adults. Clin Orthop Relat Res 1976;(119):39-47.
3. Salter RB. Role of innominate osteotomy in the treatment of congenital dislocation and subluxation of the hip in the older child. J Bone Joint Surg Am 1966;48:1413-39.
4. Brougham DI, Broughton NS, Cole WG, Menelaus MB. The predictability of acetabular development after closed reduction for congenital dislocation of the hip. J Bone Joint Surg Br 1988;70:733-6.
5. Boniforti FG, Fujii G, Angliss RD, Benson MK. The reliability of measurements of pelvic radiographs in infants. J Bone Joint Surg Br 1997;79:570-5.
6. Broughton NS, Brougham DI, Cole WG, Menelaus MB. Reliability of radiological measurements in the assessment of the child’s hip. J Bone Joint Surg Br 1989;71:6-8.
7. Kay RM, Watts HG, Dorey FJ. Variability in the assessment of acetabular index. J Pediatr Orthop 1997;17:170-3.
8. Skaggs DL, Kaminsky C, Tolo VT, Kay RM, Reynolds RA. Variability in measurement of acetabular index in normal and dysplastic hips, before and after reduction. J Pediatr Orthop 1998;18:799-801.
9. Kim HT, Kim JI, Yoo CI. Diagnosing childhood acetabular dysplasia using the lateral margin of the sourcil. J Pediatr Orthop 2000;20:709-17.
10. Pirpiris M, Payman KR, Otsuka NY. The assessment of acetabular index: Is there still a place for plain radiography? J Pediatr Orthop 2006;26:310-5.
11. Halanski MA, Noonan KJ, Hebert M, Nemeth BA, Mann DC, Leverson G. Manual versus digital radiographic measurements in acetabular dysplasia. Orthopedics 2006;29:724-6.
12. Race C, Herring JA. Congenital dislocation of the hip: An evaluation of closed reduction. J Pediatr Orthop 1983;3:166-72.
13. van der Bom MJ, Groote ME, Vincken KL, Beek FJ, Bartels LW. Pelvic rotation and tilt can cause misinterpretation of the acetabular index measured on radiographs. Clin Orthop Relat Res 2011;469:1743-9.
14. Upasani VV, Bomar JD, Parikh G, Hosalkar H. Reliability of plain radiographic parameters for developmental dysplasia of the hip in children. J Child Orthop 2012;6:173-6.
15. Spatz DK, Reiger M, Klaumann M, Miller F, Stanton RP, Lipton GE. Measurement of acetabular index intraobserver and interobserver variation. J Pediatr Orthop 1997;17:174-5.
|How to Cite this Article: Vijayan S, Ganjwala D, Shah H | Comparison of two different medial reference points for measurements of the acetabular index| International Journal of Paediatric Orthopaedics | January-June 2018; 4(1): 07-11.