What did the study look at?
In hip arthroscopy (keyhole surgery on the hip joint using a camera), fluoroscopy, a form of live X-ray imaging used during surgery, is the current gold standard. The authors note its drawbacks: exposure to ionising radiation, the need for extra staff in theatre and the burden of a heavy lead shield. Ultrasound uses no radiation and could be an alternative, but there is little evidence on how safe and effective it is during the operation itself.
The study had two aims: to compare joint distraction measured on ultrasound with joint space width measured on fluoroscopy, and to find out whether placing the arthroscopy portal under ultrasound guidance is as safe and effective as fluoroscopic guidance.
How was it done?
This was a cadaveric study, carried out on donated human bodies rather than on patients. Whole-body specimens were placed on their backs and traction was applied to one leg through a pin inserted into the lower end of the thigh bone.
- Distraction cohort: joint space width was measured at three points (lateral, apical and medial) on fluoroscopy and in a single plane on ultrasound.
- Portal cohort: each hip was randomly assigned to have its anterolateral portal created under either fluoroscopic or ultrasound guidance. All procedures were done by a single surgeon with ultrasound experience.
- Procedure time, the number of times the needle passed through the joint capsule, and any damage caused to the cartilage or labrum (the ring of tissue around the socket rim) were recorded.
What did it find?
- Distraction was measured in 20 hips from 12 specimens. On fluoroscopy, mean joint space width was 13.0 mm laterally, 16.7 mm apically and 17.9 mm medially, compared with 9.2 mm on ultrasound. The difference was statistically significant at all three points (P < .001).
- Portals were created in 17 hips from 9 specimens: 8 under fluoroscopy and 9 under ultrasound. The joint was entered successfully in every hip.
- Mean procedure time was 133 ± 51 seconds with fluoroscopy and 371 ± 260 seconds with ultrasound.
- The number of needle attempts through the capsule was 1.25 ± 0.46 with fluoroscopy and 3.33 ± 2.40 with ultrasound.
- Labral damage occurred in 6 of 9 ultrasound-guided hips (66.67%) and 1 of 8 fluoroscopy-guided hips (12.50%). There was no significant difference between the groups in cartilage damage.
The authors' conclusion
The authors conclude that ultrasound can be used to judge subjectively whether the hip is adequately distracted during arthroscopy. Ultrasound-guided portal placement, however, was associated with more needle attempts, more labral injury and a longer procedure than fluoroscopic guidance. Alternatives to fluoroscopy are still needed, but ultrasound was not shown to be superior in this cadaveric model.
Limitations
- Cadaveric tissue differs from living tissue in quality and mobility, and the model does not reproduce inflammation or bleeding, which can obscure the ultrasound image during surgery.
- Because a bony edge does not appear as a sharp line on ultrasound, joint distraction may have been underestimated.
- The authors describe the user-dependence of ultrasound as the main limitation. The surgeon was trained mainly in fluoroscopic techniques, so the results reflect the early learning curve and may not apply to surgeons experienced with ultrasound.
Reference
Trasolini NA, Sivasundaram L, Rice MW, Gürsoy S, Clapp IM, Alter TD, Gaggiotti S, Nho SJ. 2022. Ultrasound Can Determine Joint Distraction During Hip Arthroscopy but Fluoroscopic-Guided Portal Placement Is Superior. Arthroscopy, Sports Medicine, and Rehabilitation. 4(3):e1083–e1089. Licence: CC BY-NC-ND 4.0.
DOI: 10.1016/j.asmr.2022.03.005
Free full text: PubMed Central PMC9210467
This article summarises a published scientific paper for general information; it does not replace an examination or a personal medical assessment. Please consult your doctor about your symptoms.
