Sonography of the hip joint is a proven and widely used procedure for differential diagnostic clarification of pathologic (pathological) changes or symptoms in the area of the hip joint. As a noninvasive diagnostic procedure that does not require X-rays, sonography of the hip joint is a cost-effective and repeatable method. Sonography of the infant hip, for example, is used successfully as a screening procedure (see Sonography of the Infant Hip). Typical indications for sonographic diagnosis are íntraarticular volume increase (within a joint), e.g., when a joint effusion is suspected, or the evaluation of periarticular (surrounding the joint) and bony structures of the hip joint. If joint puncture is necessary, sonography precedes this procedure and provides additional guidance.
Indications (areas of application)
Sonography of the hip joint is performed when the following pathologic findings or clinical pictures are suspected:
- Bursitis (inflammation of the bursa).
- Coxarthrosis (arthritis of the hip joint)
- Coxitis (inflammation of the hip joint), different cause.
- Coxitis fugax – Sterile (germ-free) inflammation of the hip joint that is transient and classified as Reiter’s disease (synonyms: Reiter’s syndrome; Reiter’s disease; arthritis dysenterica; polyarthritis enterica; postenteritic arthritis; posturethritic arthritis; undifferentiated oligoarthritis; urethro-oculo-synovial syndrome; Fiessinger-Leroy syndrome; Engl. Sexually acquired reactive arthritis (SARA)) is classified (joint inflammation as a remote response to infection in the body).
- Coxa saltans – The so-called fasting hip consists of a jerky painful sliding of various anatomical structures over the greater trochanter (“large rolling mound of the femur”) during extension and flexion in the hip joint.
- Epiphysiolysis capitis femoris – disease of the child’s hip joint, which results in a solution of the epiphysis (growth plate) of the femoral head.
- Diseases of the rheumatic type
- Free joint body – foreign body within the joint capsule, which can lead to pain and restrictions of mobility in the joint.
- Fracture (bone fracture)
- Gluteal abscess – Encapsulated accumulation of pus in a newly formed tissue cavity in the gluteal region (buttock region).
- Hip maturation disorders – e.g. hip dysplasia, it is a congenital or acquired malposition of the hip joint in the newborn.
- Femoral head necrosis – death of the femoral head.
- Intra-articular volume increase (within a joint) – Eg. E.g., due to an articular effusion or synovitis (synovitis).
- Perthes disease – Aseptic bone necrosis of the femoral head (head of the femur) in childhood, the etiology (cause) of which is not definitively clear.
- Muscular changes
- Osseous destruction/ usurpation – local loss of bone or cartilage.
- Osteophyte – Bony growth that can cause pain and limit mobility in the joint.
- Periarticular ossification – Ossification of tissue surrounding the joint.
- Subsidence abscess – abscess at a site on the body distant from the site of origin, the subsidence or displacement of inflammation is based on anatomical structures.
- Alteration of the femoral neck torsion angle – anomaly of the femur, which can lead to malalignment of the affected leg.
- Follow-up after endoprosthesis implantation (artificial hip joint).
- Tumor – Benign or malignant neoplasm of the bone or other structures of the hip joint.
Contraindications
There are no contraindications to performing sonography of the hip when the indications are followed.
The procedure
Sonography of the hip joint is performed with the patient in the supine position. The hip joint should be in neutral zero position (anatomic normal position); if this is not possible, the rotational position of the joint should be lateral. Sonography is always performed in lateral comparison to the healthy hip joint in order to better assess anatomical conditions. A so-called B-mode ultrasound device (commercially available ultrasound device) is used for the examination.Standard slice planes are recommended for sonography of the hip joint to facilitate comparability of results and interpretations:
- Ventral region (anterior region) – transverse section and longitudinal section (section plane that is transverse (transverse) and longitudinal (longitudinal)).
- Lateral region (lateral region) – two longitudinal sections.
In the longitudinal section of the ventral region, effusion formation (intra-articular volume increase) or synovitis (synovial inflammation) can be easily identified, as the extent of the joint capsule (capsular distension) can be assessed. Furthermore, changes in the contour of the femoral head of bony origin can be visualized in this section. In the infantile hip joint, the epiphysis (growth area of the bones) of the femur (thigh bone) can be recorded. The transverse section allows visualization of the femoral artery and vein (large femoral artery and vein), which are located medial (toward the center) of the femoral head. Sonography of the lateral region is used to assess the contour of the femoral head and its acetabular roof (position in the acetabulum), and longitudinal section is used to assess the acetabular roof, e.g., in infantile hip dysplasia (malformation of the joint with reduced acetabular roof). In individual cases (e.g. Perthes’ disease), dynamic examination of the hip joint can be performed: In this case, the joint is sonographed in the adduction or abduction position (flexion and extension).
Possible complications
No complications are expected when performing sonography of the hip joint in compliance with the indications.
