Paralabral cyst of the hip
Paralabral cysts of the hip joint are a location-specific subtype of paralabral cysts. They are predominantly small, sometimes septate, well-defined multiloculated fluid intensity lesions. They are closely associated with acetabular labral tears. Their presence requires a thorough search for a labral tear which may be missed as non-arthrographic MRI imaging may look deceivingly normal.
Some authors have divided these into cysts that directly communicate with the synovial fluid of hip joint (true paralabral cysts) and those that do not (perilabral cyst). They may be confused with small bursal fluid collections around the hip joint, however, 90% of cystic lesions lateral to the iliopsoas are paralabral cysts.
Epidemiology
Usually seen in 1-4% of the asymptomatic population and in 50-70% of patients with labral tears. They are more common in males.
Clinical presentation
- anterior hip pain
- restriction of rotatory movements
- painful flexion at the hip
- snapping sensation
Pathology
There is a close association with acetabular labral tears. Common underlying etiologies include:
- developmentally dysplastic hips
- trauma (including overuse: e.g. sports injuries)
- degenerative arthrosis
It is thought that incongruity of the femoral head with acetabulum causes increased intraarticular pressure especially during flexion and rotatory movements of the hip joint, which forces the synovial fluid through the pathological labrum into the periarticular soft tissues.
Size
Usual size range is around 3-30 mm.
Location
- anterosuperiorly: the majority ~ 56%
- anteriorly: ~ 22%
- posterosuperiorly: ~ 17%
- anteroinferiorly: ~ 6%
Radiographic features
Plain radiograph
Plain radiographs have limited value for the diagnosis of labral pathology but an underlying cause (e.g. osteoarthritis or evidence of congenital hip disease) may be seen.
Ultrasound
Ultrasound is helpful in cysts larger than 1.5 cm but gives little information about the labrum.
MRI
MRI with MRI arthrography is the modality of choice to detect paralabral cysts and delineate labral tears, hip dysplasia, signs of trauma, and degenerative changes. The vast majority are seen as multilocular cysts.
- T2 / STIR: high signal
- arthrography: fill with intra-articular contrast medium.
Treatment and prognosis
Cysts may be aspirated but recur commonly. The definitive treatment is to surgically excise the cyst with an arthroscopic labral repair. Arthroscopic cyst decompression and debridement of the degenerative labral tissues were performed using an arthroscopic thermal probe and a shaver is an effective surgical method of management.
Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu paralabrale Zysten des Hüftgelenks:
