- This prospective, blinded study compared the accuracy, sensitivity and specificity of a diagnostic needle arthroscopy device and MRI in 50 patients with suspected intra-articular shoulder pathologies
- Needle arthroscopy had diagnostic accuracy similar or superior to that of MRI when both were compared with the gold standard of surgical diagnostic arthroscopy
- The accuracy of needle arthroscopy was better for ruling in various diagnoses (rotator cuff tears, glenoid and humeral articular cartilage lesions, biceps pathology and anterior labral tears) than for ruling out diagnoses
- There were no complications of needle arthroscopy (performed just prior to surgical arthroscopy) over a six-week follow-up period
- In this study, shoulder needle arthroscopy was performed in an operating room; its safety, accuracy and feasibility in the clinic setting is unknown
Minimally invasive needle arthroscopy, an emerging approach to arthroscopic and endoscopic diagnosis, can be performed with Mi-Eye, an FDA-approved device. A 14-gauge needle is attached to a single-use camera with a direct line of sight, which is then attached to a tablet computer that has most functions disabled. A syringe is connected for irrigation.
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If proven comparable to MRI, needle arthroscopy would be an appealing alternative because of its lower cost, immediate results and potential for in-office use. Jon J.P. Warner, MD, chief of the Shoulder Service and co-director of the Harvard Shoulder & Elbow Fellowship in the Department of Orthopaedics at Massachusetts General Hospital, working with fellows and other colleagues, conducted an initial comparison of needle arthroscopy in a prospective, blinded trial.
In Arthroscopy, they report that needle arthroscopy was accurate in diagnosing most intra-articular shoulder pathologies when compared with both MRI and surgical arthroscopy.
The 50 subjects presented to the clinic of a single fellowship-trained surgeon between January and July 2018 with shoulder pathology that had not responded to nonoperative management. Each underwent a physical evaluation, noncontrast 1.5-T MRI (or magnetic resonance arthrography for suspected labral tear) and needle arthroscopy under anesthesia, followed immediately by surgical arthroscopy. The article describes the needle arthroscopic procedure in detail.
Each patient's MRI was evaluated by a musculoskeletal radiologist. Videos of the arthroscopies were reviewed by three orthopedic surgeons (other than the surgeon who performed the procedures). They were blinded to the MRI and physical examination results.
- Needle arthroscopy vs. surgical arthroscopy: sensitivity 74%, specificity 97%, positive predictive value (PPV) 93%, negative predictive value (NPV) 85% (κ, 0.73)
- MRI vs. surgical arthroscopy: 74%, 86%, 78%, 83% (κ, 0.60)
Rotator Cuff Tears
- Needle arthroscopy: sensitivity 89%, specificity 100%, PPV 100%, NPV 94% (κ, 0.91)
- MRI: 100%, 72%, 70%, 100% (κ, 0.68)
- Needle arthroscopy: sensitivity 82%, specificity 95%, PPV 96%, NPV 80% (κ, 0.76)
- MRI: 89%, 80%, 86%, 84% (κ, 0.70)
Interestingly, for Buford complexes, all performance results were 100% with needle arthroscopy.
Of all pathologies, needle arthroscopy and MRI were least accurate in diagnosing labral tears:
- Needle arthroscopy: sensitivity 63%, specificity 88%, PPV 83%, NPV 71% (κ, 0.51)
- MRI: 84%, 57%, 68%, 76% (κ, 0.41)
"Ruling In" vs. "Ruling Out"
Needle arthroscopy was most accurate when used to rule in certain diagnoses, with the highest specificities and PPVs for rotator cuff tears of the supraspinatus and infraspinatus, glenoid and humeral articular cartilage lesions, biceps pathology and anterior labral tears. The number of false negatives for each of these pathologies, listed in the article, demonstrated that needle arthroscopy was slightly less accurate at ruling out intra-articular pathologies.
No complications of the arthroscopic procedures were reported over a six-week follow-up period.
Continued Scrutiny Needed
This study assessed shoulder needle arthroscopy in the controlled environment of an operating room. The accuracy and safety results should not be extrapolated to the clinic setting. It also remains to be seen how needle arthroscopy in the shoulder would perform against 3-T MRI.
Note: The authors report the following potential conflicts of interest or sources of funding: E.R.W. reports consulting fees from Stryker and research support from Arthrex, Konica Minolta, and DJO, outside the submitted work. J.J.P.W. reports other from Trice Medical, during the conduct of the study; and consultant and royalties from Smith & Nephew and Wright Medical. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
Learn more about the Shoulder Service
Learn more about the Harvard Shoulder & Elbow Fellowship at Mass General