by The Case: 71 yr old female (on Coumadin) presents to the ED after a slip and fall. Pt is laying on the stretcher complaining of left hip pain. What you see when you walk up to the bed is the patient laying like this:
Patient had distal pedal pulses, sensation and movement intact and with make shift measurement, it looked as though the malleoli were lined up (no real length discrepancy)
After addressing that this little lady was not bleeding in her head, she received x-rays of her left extremity and
pelvis:
ANTERIOR HIP DISLOCATION IN A NATIVE HIP The Hip
-The stability in the hip comes from the ball-and-socket type joint where the acetabulum covers about 40% of the femoral head along with the labrum, capsule and ligamentum teres
-Important structures to remember include blood supply from the medial and lateral femoral circumflex arteries (note: femoral head necrosis as a complication in reduction as well in delay in reduction). The sciatic nerve exits infero-posterior to the hip joint and femoral nerve anterior to the hip joint.
-Majority of hip dislocation are posterior (90%) usually caused by an axial load through a flexed knee (think: knee hitting the dashboard) and mostly associated with femoral head fractures, osteonecrosis, sciatic nerve injuries. Pt’s leg appears flex and adducted
-Anterior hip dislocations occur when the hip is in forced abduction with external rotation (think: MVC or fall). This can be further broken down into inferior “obturator” (hip is in extension and external rotation) and superior “pubic” (hip is in flexion, abduction, and external rotation).
Imaging
-AP and cross-table lateral. Cross-table lateral helps to distinguish between the anterior vs. posterior dislocation (xray below)
-Any traumatic hip dislocations need to be followed by a post reduction CT to help rule out femoral head fx, loose bodies, acetabular fractures
References:
https://www.orthobullets.com/trauma/1035/hip-dislocation https://radiopaedia.org/articles/anterior-dislocation-of-the-hip?lang=us https://pubs.rsna.org/doi/full/10.1148/rg.2017170012 https://www.ncbi.nlm.nih.gov/books/NBK507814/
