European Journal of Cardiovascular Medicine

The acetabulum, a vital component of the hip joint, is a cup-shaped cavity located on the lateral aspect of the hip bone. Its name, derived from Latin, translates to "shallow vinegar cup," reflecting its concave morphology. Functionally, it plays a crucial role in hip mobility by articulating with the femoral head, forming a ball-and-socket type of synovial joint that facilitates a wide range of movements while ensuring stability. Anatomically, the acetabulum consists of two distinct regions: the lunate articular surface and the central non-articular fossa. The lunate surface, covered in hyaline cartilage, serves as the primary weight-bearing region, allowing seamless articulation with the femoral head. In contrast, the acetabular fossa, located at the center of the cavity floor, is filled with fibroelastic fat and lined with a synovial membrane, contributing to cushioning and joint lubrication. Structurally, the acetabulum is formed by the fusion of three pelvic bones—the ilium, ischium, and pubis—each contributing to different sections of the cavity. The pubis constitutes the anterior one-fifth, the ilium forms the posterosuperior two-fifths, and the ischium makes up the posteroinferior two-fifths. Inferiorly, the articular surface is interrupted by the acetabular notch, a gap bridged by the transverse acetabular ligament, which reinforces joint integrity. The depth of the acetabulum (DH) is further enhanced by the acetabular labrum, a fibrocartilaginous rim that surrounds the cavity. This labrum plays a critical role in securing the femoral head within the acetabulum, thereby improving joint stability, optimizing load distribution, and reducing friction during movement. Thus, the acetabulum, an essential component of the hip joint, plays a crucial role in providing stability and enabling a wide range of motion necessary for daily activities such as walking, running, and sitting. As a key articulating structure in the hip, it bears significant biomechanical loads and distributes forces efficiently between the pelvis and femur. Given its fundamental importance, any pathological or structural alterations within the acetabulum can severely affect joint function and overall mobility. Total Hip Arthroplasty (THA) has emerged as one of the most widely accepted and effective surgical interventions for patients suffering from debilitating hip conditions such as osteoarthritis, avascular necrosis, and fractures. The primary goal of Total Hip Arthroplasty (THA) is to restore pain-free mobility while ensuring the longevity of the prosthetic components. The successful outcome of Total Hip Arthroplasty (THA) is highly dependent on precise implant positioning within the acetabulum, as improper placement can lead to a range of postoperative complications. These complications include hip joint instability, impingement, dislocation, and accelerated wear of the prosthetic components, ultimately affecting the long-term functionality of the hip joint. One of the most vital load-bearing joints in the human body is the hip joint, which enables efficient locomotion and weight distribution. Previously classified as a ball-and-socket synovial joint, the hip joint is now frequently described using the term "rotating conchoids," which more accurately conveys its complex range of motion and biomechanical properties [1]. The acetabulum itself, often referred to as the "shallow vinegar cup," is a deep, cup-shaped cavity positioned laterally on the hip bone and formed by the fusion of three major pelvic bones—the ilium, ischium, and pubis. This anatomical confluence contributes to the strength and resilience of the hip joint, supporting various dynamic movements. The acetabulum is encircled by a prominent ridge known as the acetabular rim, which serves as a structural boundary and plays a significant role in maintaining joint integrity [2]. Anatomically, the acetabulum consists of both articular and non-articular regions. The non-articular portion, termed the acetabular fossa, is a rough central depression that forms the acetabular floor. In contrast, the articular region, referred to as the lunate surface, is the primary weight-transmitting area responsible for accommodating the femoral head during movement and weight-bearing activities [3]. Proper acetabular development is crucial for optimal hip biomechanics, ensuring that forces are evenly distributed and preventing abnormal joint loading. The formation of the acetabular cavity begins between the fourth and sixth weeks of intrauterine life, with the pre-cartilaginous template appearing by the seventh week of gestation. By the eighth week, the acetabulum is fully developed and structurally capable of supporting the femoral head. However, congenital anomalies, such as hip joint displacement, can disrupt normal articulation, leading to severe functional impairments. One of the most frequently observed congenital conditions, developmental dysplasia of the hip (DDH), results in improper positioning of the femoral head within a shallow acetabular cavity. Early diagnosis and intervention, including hip arthroscopy and corrective procedures, are necessary to manage such cases effectively and prevent long-term complications [4]. Morphometric analysis of the acetabulum involves a detailed quantitative assessment of its anatomical characteristics, which have a profound influence on surgical decision-making, implant design, and the overall postoperative outcomes of hip arthroplasty procedures. Accurate measurements of acetabular parameters serve as essential references in clinical practice, aiding orthopedic surgeons in selecting appropriate prosthetic components and optimizing surgical techniques [5, 6]. Several morphometric indicators, including acetabular angles and Centre Edge (CE) angles, play a significant role in evaluating hip dysplasia and guiding patient rehabilitation strategies [7]. Furthermore, a comprehensive understanding of acetabular anatomy contributes to the investigation of the underlying etiopathogenesis of hip disorders such as primary osteoarthritis, thereby facilitating improved treatment approaches and patient care.

Aim and Objectives: The aim of this study was to conduct a morphometric analysis of the acetabulum that belonged to the East Indian population and investigate its clinical significance in total hip arthroplasty.

In this cross-sectional study, 50 adult dry hip bones (among which 25 belong to the right side and 25 belong to the left side) of unknown gender and age were studied in the Department of Anatomy, Indira Gandhi Institute of Medical Sciences, Patna, Bihar (India).

Inclusion criteria:

• Hip bone with the intact acetabulum: Only well-preserved bones that were suitable for accurate morphometric measurements were taken.
• Age and Sex:
• Bones from adult individuals of various age groups were included.
• Both male and female bones were considered.
• Specimen Quality:
• Bones that were free from significant deformities, fractures, or pathological conditions affecting the acetabulum were taken.

Proper handling and care were exercised to maintain the integrity of the specimens throughout the study.

Exclusion criteria:

• Severely Damaged or Fragmented Bones:
• Bones that were extensively damaged, fragmented, or showed significant deformities affecting the acetabulum.
• Pathological Conditions:
• Bones exhibiting pathological conditions such as tumors, infections, or systemic diseases affecting the acetabulum.
• Bones with evidence of previous surgical interventions or orthopedic procedures that may alter the natural morphology of the acetabulum.
• Non-human Specimens:
  • Exclusion of non-human bones or specimens from the study.

Linear measurements were taken with the help of a digital vernier caliper, which had a sensitivity of 0.01 mm, and the least count observed was 0.01 mm. Measurements were taken twice, and the average was included in the analysis. The obtained data is expressed in terms of Mean and standard deviation. A p-value less than 0.05 was considered significant in this study for the analysis. The findings were tabulated and analyzed statistically by using the GraphPad Prism version 9 software.

The following parameters were observed:

1. Diameter of the acetabulum: The maximum anteroposterior distance of the acetabulum, measured by the digital vernier caliper (from point A to B) (Figure 1).
2. Depth of the acetabulum: The maximum vertical distance from the brim of the acetabulum to the center deepest point in the acetabular fossa. It was measured by placing a metallic scale across the brim of the acetabular cavity (from point C to D) (Figure 1).
3. Width of the acetabular notch: The distance between the two ends of the lunate-shaped articular part of the acetabulum (from point E to F) (Figure 1).

Figure 1: Showing different points used for the measurement of the acetabulum.

P. Diameter of the acetabulum (from point A to B),

Q. Depth of the acetabulum (from point C to D);

R. Width of the acetabular notch (from point E to F).

Our morphometric analysis demonstrated that the mean acetabular diameter measured 48.42 ± 3.40 mm on the right side and 47.05 ± 5.55 mm on the left side, while the acetabular depth was 24.16 ± 2.59 mm on the right side and 24.96 ± 3.14 mm on the left side. The width of the acetabular notch showed similar dimensions between sides, measuring 22.55 ± 3.07 mm on the right and 22.82 ± 3.06 mm on the left. Statistical comparison revealed no significant differences between the right and left sides for any of these acetabular parameters (p > 0.05), indicating bilateral symmetry in the anatomical dimensions of the acetabulum within our study population, as detailed in Table 1. These findings suggest consistent morphometric characteristics between both hips, which may have important implications for surgical planning and prosthesis design in total hip arthroplasty procedures.

Table 1: Showing different parameters of the acetabulum.

All measurements were taken in mm.

The morphometric study of the acetabulum presented in this research highlights the importance of understanding individual variations in hip joint anatomy. By establishing correlations between acetabular dimensions, orthopedic surgeons can improve their decision-making process during total hip arthroplasty. Accurate preoperative planning, aided by these insights, can lead to optimized implant positioning, reduced complications, and enhanced patient outcomes. In diverse populations around the world, researchers have looked at different variations of the morphometry of the acetabulum of the hip bone. We compared the observations of different researchers from around the world with our observations, as shown in Table No. 02.

Table 2: Showing comparison of the measurements of different parameters of the acetabulum.

In the present study, the mean diameter of the acetabulum on the right side was 48.42 ± 3.4 mm, and on the left side was 47.05 ± 5.55 mm, which was much nearer to the findings of Yugesh and Kumar [14] and Singh A et al. [19], while Aksu F et al. [9], Ukoha UU et al. [13], and Indurjeeth K et al. [17] reported much larger values than our observations. For the hip to function normally and to have a wide range of motion, acetabular depth is crucial. It acts as one of the contributing factors in component dislocation [16]. Many researchers believe that the acetabular depth is a critical indicator of acetabular dysplasia. Acetabular dysplasia is defined as an acetabulum with less than a 9 mm depth [10]. In the present study, the depth of the acetabulum on the right side was 24.16 ± 2.59 mm, and on the left side was 24.96 ± 3.14 mm, which was much nearer to the findings of Saikia et al [10], Gangavarapu and Muralidhar [15] and Sreedevi G and Sangam MR [15], while Aksu F et al. [9], Ukoha UU et al. [13] and Yugesh and Kumar [14] were reported much larger value than our observations. These differences in the results may be due to racial variations and different geographical distributions.

We observed the width of the acetabular notch was 22.55 ± 3.07 mm on the right side and 22.82 ± 3.06 mm on the left side, while Sreedevi G and Sangam MR [15] reported that the width of the acetabular notch on the right and left sides was 22.25±2.97 mm and 22.82 ± 3.06 mm respectively and Yugesh and Kumar [14] observed that width of the acetabular notch was 30.8±0.42mm and 31.1±0.72mm in right and left side respectively.

The clinical significance of these findings is complex and multifaceted. The documented symmetry in normal acetabular anatomy supports the idea of standardized surgical approaches for uncomplicated total hip arthroplasty cases. However, the variations observed in this study, compared to other research, highlight the importance of considering population-specific factors when it comes to prosthetic design and placement. Accurate preoperative assessment of acetabular dimensions is particularly crucial in populations that exhibit significant anatomical differences from Western norms, which have traditionally informed implant design. The theoretical implications of these findings contribute to the ongoing discussion regarding the balance between anatomical standardization and the need for population-specific customization in orthopedic implant design. The demonstrated variations support the notion of regional morphological patterns in pelvic anatomy, challenging the universal applicability of implant systems developed primarily for Western populations. This is significant for the global orthopedic industry, suggesting that achieving optimal patient outcomes may require more nuanced approaches to implant design that take ethnic variations in skeletal anatomy into account. Practically, these insights are important for clinical practice. The consistent symmetry noted in normal hips supports the use of standardized implant sizes, while the population-specific variations emphasize the need for adaptable prosthetic systems. Surgeons treating patients from our demographic may find it beneficial to be aware of the typical acetabular dimensions identified in this study when selecting components and planning their surgical approaches. The finding that the acetabular characteristics of our population differ from those reported in some other studies reinforces the importance of region-specific anatomical research to guide clinical decision-making. The broader implications of this research extend to several facets of orthopedic care. For implant manufacturers, these findings suggest the potential value of developing region-specific component designs that align more closely with the anatomical characteristics of various populations. For surgical educators, the results underscore the need to incorporate population-specific anatomical knowledge into training programs. For clinical researchers, this study highlights the importance of continuing to investigate anatomical variations across different demographic groups to refine surgical techniques and improve patient outcomes.

Limitations: Limitations of this study were that the age and sex of the hip bones were not studied, as it was not available.

A precise understanding of acetabular morphology is fundamental in the development of optimized prosthetic components for total hip arthroplasty. The present study identified key morphometric parameters that can significantly enhance preoperative planning by enabling accurate assessment of the acetabulum. These insights provide biomedical engineers with essential data to design prostheses that align seamlessly with individual anatomical variations, improving implant stability, longevity, and functional outcomes. By integrating these findings into prosthesis development and surgical approaches, the study contributes to advancements in personalized orthopaedic interventions, ultimately enhancing patient mobility and quality of life.

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