A STUDY OF MEASUREMENT OF ACETABULAR DIAMETER RADIOLOGICALLY IN NORTHERN INDIAN POPULATION OF JAMMU REGION

Dr.Jawahar Mehmood Khan 1 , Dr.Mohd Irfan Banday 2 and Dr.Jabreel Muzaffar 3 . 1. JR Department of orthopaedics GMC Jammmu. 2. Orthopaedic surgeon J&K health services. 3. SR department of orthopaedics Shri Mahant Indresh Hospital Dehradun. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

The acetabulum is a cup-shaped socket of the hipbone that derives its name from its resemblance to a shallow Roman vinegar cup. In clinical medicine, measurements of the acetabulum are crucial in diagnosis, monitoring patient recovery, determining stability of the hip joint and in assessment of acetabular dysplasia. The decision for operative treatment is often based on different radiographic measurements and scores for which normal values are defined. Therefore orthopaedic surgeons often use combinations of measurements when assessing acetabular parameter. A number of authors have also shown that geometrical measurements of acetabulam differ with respect to age, sex, and race and even within regions. The size, shape and depth of the acetabulum are variable as reported by Govsa F et al., Therefore, the knowledge of various parameters of acetabulum would be helpful in performing surgical procedures such as acetabular reconstruction and planning reorientation procedures using spikes and screws for fixation.

…………………………………………………………………………………………………….... Introduction:-
The acetabulum is a cup-shaped socket of the hipbone that derives its name from its resemblance to a shallow Roman vinegar cup. The acetabulum forms from the coalescence of three ossification centers (collectively called the 'triradiate cartilage'): ilium, pubis and ischium. The triradiate cartilage gives rise to the anterior wall, posterior wall and the dome of the acetabulum. The triradiate cartilage subsequently closes between ages 14 to 16 .The acetabulum has an average diameter of 52 ± 4 mm. Men tend to have larger diameters compared to women. Average anteversion of the native acetabulum measures 16 to 21 degrees with an average inclination of 48 degrees . Men tend to have less anteversion than females. The transverse acetabular ligament, located inferiorly, connects the anterior and posterior walls of the acetabulum forming a tension band against deformation of the wall from force transmission. The acetabulum is supported by two strong columns of bone. The anterior and posterior columns connect the acetabulum to the pelvis and allow force transmission between the trunk and the lower extremity.
The acetabular fossa is a central cavity containing the ligamentum teres and a fat pad called pulvinar. The ligamentum teres connects the acetabulum to the fovea of the femoral head. It has been hypothesized to be a pain generator and instrumental in synovial fluid distribution and stability. The labrum, which arises from the limbus, is a ring of connective tissue surrounding the outer edge of the acetabulum.

Materials And Methods:-
The study was conducted in Government Medical College Jammu from October 2016 to November 2017 on the pelvic radiographs of 300 patients. All age groups of the patients who had undergone for pelvic x-ray AP view routinely for their clinical indication with radiologically normal xrays were included in the study. These pelvic radiographs were obtained using the standardised protocol: in 15-30 degrees of internal rotation of the hips in the supine position with a film-focus distance of 100 cm and the beam centered on the symphysis pubis. The magnification power of x ray machine was kept 54%.The values were calculated by multiplying by factor 1.85.
The observations and measurements were made with regards to acetabular diameter. All other data like age, sex, presenting complaints were being collected from available records at the Medical records department. This collected data was tabulated and analysed. Appropriate stastical technique was applied and help of statistician was sought to find out prevalence and significance of any apparent association based on type of data available. Data was distributed normally with the help of statistician of our medical college for comparison of genders.
Acetabular size:-Inclusion Criteria:-All age groups who had gone to get an x-ray of pelvis for any clinical indication on routine basis in OPD/EMERGENCY/WARD in the Department of Orthopaedics of Govt.Medical College Jammu were included in the study.
Exclusion Criteria:-Radiographs of patients with osteoarthritis, metabolic diseases, hip fractures and pathological (metastatic) hip fracture were excluded from the study .
Stastistical Analysis:-Appropriate stastical technique was applied to find out prevalence and significance of any apparent association based on type of data available.

N=no of observations Sd=standard deviation
The mean acetabular size in males was 59.94± 0.85 mm (40-74). The mean acetabular size in females was 59.72± 1.15 mm (52-70). The difference in the mean acetabular size of males and females was found to be statistically insignificant (p value is 0.05).

Discussion:-
The studies on acetabular diameter have been done in different authors in different parts of the world. Variations in acetabular diameter has been found and this can be attributed to varying level of activity, genetics, race, diet and lifestyle. Despite lot of research in the anatomic and biomechanical factors which influence the modality of treatment of orthopaedics conditions, consideration of acetabular diameter has gained less importance in assessment of hip biomechanics and preoperative planning and templating of hip surgeries. Present study was aimed to measure hip joint anthropometry radiologically in our region and compare it to the studies available and to find if any difference exists. We measured acetabular size on standard AP view radiograph of people attending our hospital who required pelvis radiograph with otherwise normal hip joints.
It is necessary to evaluate the diameter of the acetabulum as part of the preoperative planning in order to estimate the size of the acetabular cup in the surgical procedure of the acetabulum, especially in total hip arthroplasty. The measurement of the acetabular diameter was performed in the anteroposterior view of the pelvic radiograph, and the commercial template is routinely used to solve the magnification problem and to estimate the size of the acetabulum and the prosthesis.