Example Of Term Paper On Radiological Assessment Of Hip Dislocation Injury

Introduction

Hip dislocation injury is the displacement of the head of the thighbone from its socket from the pelvis (Martinoli, et. al., 2012). This displacement occurs when a lot of pressure impacts the site, which could be from accidents and falls. According to Khanna, Harris, Farrojhyar, Choudur & Wong (2014), older people are more predisposed to this condition compared to the younger people, although the condition is as prevalent among the older as it is among the younger adults. Adults may have to sustain a large amount of trauma for a hip dislocation to occur, although children may suffer from the condition from minor trauma.
Hip dislocation can either be posterior, anterior, or central dislocation. Posterior hip dislocation occurs when there is a major trauma to the joint while the muscles of the leg are flexed. Anterior hip dislocation occurs when there is an extended rotation to the hip during trauma. On the other hand, central dislocation of the hip occurs when the head of the femur is driven into the length of the femur by major force, resulting to an abducted foot (Khanna, et al, 2014). This paper will explore hip dislocation injury, with radiological assessment as the main focus.

Review of Related Imaging Based on the Diagnostic Validity of Each Modality

Radiological assessments are ways of obtaining the internal pictures of the body for clinical analysis and medical intervention (Maak, Fabricant & Kelly, 2014). The unique feature of radiological assessment compare to other recording techniques such as electrocardiography is that radiological assessment produces images of the internal organs (Wright, Chong, Kielar, Hallstrom & Jacobson, 2014). These pictures display any abnormalities in the body. Hip dislocation injury can be diagnosed using various radiological assessment techniques as discussed below:

X-rays

Also commonly known as radiographs, x-rays machines (Fig 4) are probably the oldest forms of imaging in the medical field (WHO, 2015). X-rays make use of small doses of electromagnetic radiation that penetrate the bone and tissue matter of the body and produce a visual image of the bony part and the body tissues (WHO, 2015). The images from an x-ray differ with the density of the bone or tissues, hence, able to detect fractures by how the light travels along the affected part (Hussain, et al 2014). X-rays are non-invasive diagnostic methods that can detect fractures, dislocations, and other changes in the bones and tissues of a human being (Hussain, et al, 2014). To obtain the best images from an x-ray, the radiologist may need to take the images from varying positions. This enhances the diagnostic validity of x-rays, ensuring that there are no false-positives or false-negatives during the diagnosis (Maak, Fabricant & Kelly, 2014). However, to improve the diagnostic validity of radiographs, a later imaging should be carried out since its validity increases as the bone density reduces along the fracture, or as the fracture becomes denser (Mallee, et al, 2012).

Radionuclide Bone Scan (RNS)

An RNS, (Fig 2) is a diagnostic method for hip bone fractures and dislocations that uses radio-isotopes and methylene diphosphonate, which is absorbed into the density of the bone to form hotspots (Wright, et al, 2014). Isotopes are intravenously injected into the body, followed by a three hour delay before the scan is performed (Wright, et al, 2014). The scan is done using a gamma camera which shows an increase in the absorption of the isotopes where there is a fracture (WHO, 2015). However, this method produces the same results for fractures as it would in people with arthritis and synovitis diseases. Therefore, to ensure the validity of this diagnostic modality, it is best to wait for 72 hours to avoid false-negatives (Hussain, et al, 2014). Hip dislocation injury, however, is a painful injury and diagnosing it as soon as possible is critical in not only avoiding more pain, but also in avoiding more damage to the damaged hip bone. However, the more modern three-phase method is argued to produce good results within 24 hours (Wright, et al, 2014). The diagnostic validity of RNS has been proven to be low by studies, indicating a sensitivity of 78%-98%. This implies that 2%-25% of fractures diagnosed using RNS can actually be missed.

Ultra Sounds

Unlike other the RNS and the x-rays, ultra sound imaging (Fig 3) produces imagery through the ultrasound waves which are deflected off a surface and onto a recording form (Martinoli et. al., 2012). To produce good and quality images using ultra sounds, the probe and the skin are required to be in good contact, also known as coupling. Coupling in ultrasounds is achieved by use of a special gel which is massaged onto the site of injury. However, this can be challenging when the site is too painful or swollen, as could be the case in a hip dislocation injury (Hussain, et al 2014). Ultrasounds are the preferred choice of many because they present no chances of ionizing radiation, and are also relatively cheap and widely available. A study comparing the specificity and the sensitivity of ultrasound showed that its diagnostic validity in terms of sensitivity is 100%, although specificity was 75% (Martinoli et. al., 2012).

Computed Tomography Scans (CT scans)

A CT scanner (Fig 5) utilizes an x-ray tube and sensitive detectors to obtain imagery from the affected site (Mallee, et al, 2012). CT scans usually acquired traverse axial images, which makes fractures running parallel to the axial plane elusive to capture. To curb this limitation, modern innovations have brought about multi-detectors that make it possible to obtain 2D images. The acquisition of images from a CT scan is very rapid, and further enhances the creation of 3D images which can be displayed from various dimensions (Hussain, et al, 2014). One limitation to the use of CT scans in diagnosing hip dislocations is that it doesn’t detect changes in the marrow of the bone, which is a common symptom in hip fractures. CT scans are rapid procedures, making them most preferred for diagnosis of hip fractures, which is a very painful condition (Wright, et al, 2014). According to WHO (2015), CT scans are not as safe as other methods due to the high exposure to radiation.

Magnetic Resonance Imaging (MRI)

An MRI machine (Fig 1) is a diagnostic modality that produces imagery by use of magnetic radiation (WHO, 2015). The images from MRIs are real time and in 3D, with a clear contrast of the body tissues, which makes its visualizations perfect for diagnosis of hip dislocations and fractures. MRIs can capture images from various dimension of the body without mobilizing the body, a feature that makes it preferred for people with multiple injuries which might be worsened by mobilization (Hussain, et al, 2014). In some cases, some contrast medium may be used together with MRIs to enhance the images. Since it uses magnetic resonance, any implants and metallic objects that a patient may have on them must be removed or carefully evaluated (Maak, Fabricant & Kelly, 2014). MRIs are relatively safe since there is no great exposure to radiation compare to the CT scans. Also, MRIs, unlike other diagnostic radiological assessments, is safe for use in pregnant women. The diagnostic validity for this excellent compared to other radiological assessments.

Nuclear Medicine

Nuclear medicine is a modern diagnostic modality that involves the inhalation or injection of radioactive tracers that enhance the visualization of the internal organs of the body by emitting gamma radiations that are captured by a gamma camera (Naal, Miozzari, Schar, Hesper & Notzli, 2012). The radioactive agent is usually added to a pharmaceutical product which is specific to the site being imaged. For example, if it is a hip dislocation, the radioactive agent can be added to painkillers given to the patient to reduce the pain (Mallee, et al, 2012). Distribution of the tracer is detected in the body by the gamma camera, which then projects 3D images onto a screen in digital format. However, this radiological assessment is not recommended for pregnant and breastfeeding women.

Conclusion

In conclusion, this paper discussed radiological assessments of hip dislocation injury and identified six imaging modalities that can be used to diagnose a hip dislocation. Although these modalities are widely used by radiologists, they have their benefits and drawbacks as well. There are those modalities that expose the patient to radiation, like x-rays, but are cheap and readily available; while there are other modalities that are safe even for pregnant and breastfeeding women, but they are expensive and not readily available, like the MRIs. While all these modalities are necessary in diagnosing hip dislocations, some of them have a higher diagnostic validity than others. Literature reviews on the various radiological assessments of hip dislocation reveal that the MRIs are not only safe, but they also have a high diagnostic validity compared to other modalities (Hussain, et al, 2014).
Appendices

References

Hussain, A. M., Packota, G., Major, P. W., & Flores-Mir, C. (2014). Role of Different
Imaging Modalities in Assessment of Temporomandibular Joint Erosions and
Osteophytes: A Systematic Review.
Khanna, V., Harris, A., Farrokhyar, F., Choudur, H. N., & Wong, I. H. (2014). Hip
Arthroscopy: Prevalence of Intra-articular Pathologic Findings After Traumatic Injury
of the Hip. Arthroscopy: The Journal of Arthroscopic & Related Surgery,
30(3), 299-304.
Maak, T., Fabricant, P., & Kelly, B. T. (2014). Sports Specific Injuries of the Hip Joint. In
The Young Adult Hip in Sport (pp. 87-106). Springer London.
Mallee, W. H., Doornberg, J. N., Poolman, R. W., Kloen, P., Maas, M., & de Vet, H. C.
(2012). Computed Tomography versus Magnetic Resonance Imaging versus Bone
Scintigraphy for Clinically Suspected Scaphoid Fractures in Patients with
Negative Plain Radiographs. The Cochrane Library.
Martinoli, C., et. al. (2012). Hip ultrasound. European Journal of Radiology, 81(12), 3824
3831.
Naal, F. D., Miozzari, H. H., Schär, M., Hesper, T., & Nötzli, H. P. (2012). Midterm Results
of Surgical Hip Dislocation for the Treatment of Femoroacetabular Impingement. The
American Journal of Sports Medicine, 40(7), 1501-1510.
World Health Organisation, WHO. (2015). Diagnostic Imaging. Retrieved March 17, 2015,
Wright, A. T., Chong, S. T., Kielar, A. Z., Hallstrom, B. R., & Jacobson, J. A. (2014).
Emergency Evaluation of Acute Hip Fractures: Role of MRI and Orthopedic
Intervention. Contemporary Diagnostic Radiology, 37(12), 1-5.