Hip pathology
Hip Effusion
Joint effusion is diagnosed when fluid (either anechoic or hypoechoic) is evident between the anterior layer of the synovium and the femoral neck. The presence of a hip effusion is found frequently in adults suffering from hip pain.
Inflammatory joint diseases such as rheumatoid arthritis (RA) and septic arthritis are often seen with a joint effusion.
Hip Effusion
This is anechoic fluid bordered by the red marker.
There is fluid along the femoral neck.
Scan the patient supine with the leg slightly externally rotated and run the transducer along the neck of femur (NOF).
Iliopsoas Bursitis, Tendonitis or Abscess
The iliopsoas tendon is the common tendon of the iliacus and psoas muscles of the lateral pelvis and spine. It is a hip flexor and external rotator.
As it crosses the tendon tendon passes immediately anterior to the medial edge of the hip joint. It then curves and dives to insert onto the lesser trochanter of the femur.
The iliopsoas bursa is the largest bursa in the body.
A normal iliopsoas tendon.
Ultrasound showing an oedematous iliopsoas tendon and bursal thickening/fluid.
Iliopsoas abscess
The fluid is heterogeneous, with internal septations.
Iliopsoas Bursitis
An enlarged iliopsoas bursa
The bursa was easily aspirated with a 22G 2″ needle (red arrow).
A comparison image showing a normal right iliopsoas tendon insertion and the abnormal left side.
Iliopsoas tendon insertional tear
Trochanteric Bursitis
The trochanteric bursa is the most superficial and posterolateral of the many bursae that surround the hip joint.
It lies just below the level of the superior greater trochanter and deep to the gluteus maximus and iliotibial band.
It is a large bursa and can extend significantly laterally and inferiorly.
Importantly, absence of fluid on ultrasound, DOES NOT exclude trochanteric bursitis
Trochanteric bursitis is visualised as a linear anechoic line coursing along the gluteus medius.
This is often only a thin layer of fluid and is often best visualised initially with the patient supine and scanning in a transverse plane postero-laterally.
Superficial Trochanteric bursitis
The following patient experienced relief from a cortico-steroid injection along with an aspiration of 10cc of purulent fluid.
An example of marked trochanteric bursal fluid (>15cc).
Axial view of the same superficial trochanteric bursitis.
Haematoma
This patient sustained a fall 3 weeks before a lump had formed on the lateral hip. It was only painful on palpation.
The haematoma tracks over the iliotibial band at the level of the greater trochanter.
Gluteal Pathology
Gluteal Tendinopathy
Tendinopathy is caused by the inability of a tendon to adapt to loading. There is microtrauma and attempted healing.
Tendinopathy and bursitis of the gluteal insertions is another common disorder of the middle aged and elderly. It may also occur in younger more athletic patients possibly because there is a core imbalance.
The gluteus medius tendon inserts onto the greater trochanter, with two insertions one to the superior facet and one to the lateral. Deep to the tendon is the sub gluteus medius bursa. Gluteus minimus inserts anteriorly and also has its own bursa.
Gluteus Medius Tendinopathy.
There is a loss of normal architecture. There is often an increase in vascularity. Often it is chronic so enthesopathy will be seen ie intrasubstance calcification within the tendon, often at the insertion.
Gluteus Medius Tendon Tear
Transverse view of the gluteus medius tear.
Coronal view of the tear in the gluteus medius tendon.
There is fluid in the region and the tendon has retracted.
Enthesopathy
This is usually seen in patients with chronic lateral hip pain and tenderness on palpation. Generally over the tip of the greater trochanter at the gluteus minimus and medius tendons.
Enthesopathy is a process rather than a disease. It is a disorder at the site of the insertion of ligaments, tendons, fascia, or articular capsule into bone (enthesis) .This process also may promote abnormal calcification or ossification of the tendon or ligament at the insertion into the bone.
Tears of the tendon may also be seen. Gluteus medius and minimus enthesopathy is a distinct clinical entity.
Enthesopathy
Calcification at the gluteus minimus and medius tendon insertions.
Snapping Hip
Snapping can have intra-articular causes such as osteo-arthritis, labral tears or cysts. These may not be visible on ultrasound.
The 2 most likely forms of snapping hip encountered with ultrasound are:
- Lateral Snapping hip syndrome.
This involves the ilio-tibial band catching on the greater trochanter or gluteal tendon insertions. To evaluate this, roll the patient onto the unaffected side and scan transversely over the greater trochanter. With the leg flexed, ask the patent to lift their feet apart, whilst keeping their knees together. Watch the ITB. It should slide smoothly over the trochanter and gluteals. (see normal video here)
- Anterior Snapping hip syndrome.
This occurs less commonly. It involves the ilio-psoas musculo-tendinous junction catching on ilio-pectineal ridge. This occurs during movement from hip flexion to extension.
With the patient supine, ask the patient to flex, then aBduct the hip (frog-leg position). Then return to full extension so the feet are side-by-side. It is on this return to extension that the click will occur.
To observe this on ultrasound, scan the iliopsoas tendon in transverse at the level of the pubis.
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Vastus Lateralis Lipoma
This patient was sent for an ultrasound because he felt a lump in his leg and had pain overnight.
An intramuscular echogenic well circumbscribed mass was present within the vastus lateralis muscle belly of the quadricep group.
When a fatty tumour is seen in a muscle a liposarcoma should be considered . They are malignant and can metastasize.
Within the central muscle belly of the vastus lateralis muscle in the mid thigh , there is a well defined ovoid shape hyperechoic lesion. It measures 7.6×2.7×10.4 cm. There was no significant internal vasculature seen.
Due to the size and the intramuscular position a CT was performed with and without contrast. It showed that the lesion was a intramuscular lipoma with no aggressive features detected.
Labral Pathology
Labral tears and labral cysts.
Labral cysts are generally the sequelae from labral tears, with synovial fluid extending through the defect.
Complicated , chronic labral cysts.
The labral cysts are swelling the labrum. The patient had groin pain, but also muscular thigh pain, likely due to the combination of altered gait and pressure on the muscle origins by the thickened labrum.
Femoro-Acetabular Impingement (FAI) CAM lesions
Involves entrapment of the anterior labrum and capsule of the hip, secondary to boney irregularity of the acetabular margin, and or femoral neck reducing the natural range of movement.
Subtypes :
Cam: Where there is loss of the femoral head/neck concavity.
Pincer: Where there is bossing of the actetabular margin.
Mixed: A combination of Cam and Pincer types
The sub-types of Femoro-Acetabular Impingement.
REF: Lavine Et Al 2004
This image shows a PINCER type CAM lesion. The arrows indicate the irregular neck of femur. The loss of head-neck shape is also evident.
Osteophytic lipping of the acetabulum and the cam-lesion on the anterior femoral neck (red arrow) support the diagnosis of femoro-acetabular impingement (FAI).
The normal right hip and abnormal left hip.
Osteophyte off acetabulum (blue arrow) and the cam-lesion on the anterior femoral neck (red arrow).
Tensor Fasciae Latae
Lymph Nodes
The same principles apply to lymph nodes anywhere:
- Height should be less than length.
- An echogenic fatty hilum should be present.
- Should have a homogeneous, smooth hypoechoic cortex.
- Only subtle vascularity with a single hilum.
This lymph node has lost its fatty hilum. It has become rounded and not elongated like a normal lymph node. It is heterogeneous and hypoechoic. Abnormal lymph nodes can become anechoic and appear cystic.
Increased Vascularity in an abnormal Lymph node.
Fibromatosis
This patient felt a lump in her groin which was growing .The overlying skin is normal. It was painful.
A biopsy was done and the diagnosis was as follows:
“This may represent reactive
fibroblastic proliferation at the periphery of an old haematoma, but
also raises consideration of the possibility of old haemorrhage into a
spindle cell lesion, a form of fasciitis or fibromatosis.”
These tumours often appear as infiltrative, usually well-differentiated, firm overgrowths of fibrous tissue, and they are locally aggressive. They may recur after excision. They commonly arise from the rectus abdominis muscle in postpartum women and in scars due to abdominal surgery, they may arise in any skeletal muscle.
Inguinal ligament is adjacent to the groin lump. The lump lies within the aponeurosis of the rectus abdominis muscle distally.
Fibromatosis is hyperaemic.Infiltration of the adjacent muscle bundles to entrap them and cause degeneration is commonly seen. .
Myositis Ossificans Vastus Intermedius
This patient is 17 years old and sustained trauma during a rugby match 6 weeks ago.
A lump had formed and it was still painful. Under ultrasound a large 12cm long heterogeneous mass with calcification was present in the vastus intermedius. This is consistent with the growth of bone and cartilage within the skeletal muscle after a contusion injury from blunt trauma. Myositis ossificans traumatica makes up 65-75% of all cases.
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References
Sonographic Findings of Groin Masses J Ultrasound Med May 1, 2007 26:605-614
Imaging of abdominal wall hernias Imaging December 1, 2006 18:268-277
van den Berg JC, Rutten MJ, de Valois JC, Jansen JB, Rosenbusch G. Masses and pain in the groin: a review of imaging findings. Eur Radiol 1998; 8:911-921.
Ovary-Containing Hernia in a Premature Infant: Sonographic Diagnosis J Ultrasound Med July 1, 2007 26:985-987