Recognition of stifle disease appears to be increasing, and estimates put the incidence in some athletic disciplines as high as 40%. While treatment options are expanding, definitive diagnosis of slight to moderate stifle pathology has long been limited, for a number of reasons:
- Traditional diagnostic arthroscopy (using scopes from 2.7mm and up), while it allows for both diagnosis and therapy, requires general anesthesia, rehabilitation time, and significant cost…all of which factor in to difficulty securing owner/trainer buy-in.
- Many practitioners are uncomfortable performing diagnostic anesthesia of the stifle.
- Many lesions (particularly soft tissue lesions) go undetected with radiography.
- Ultrasonography has helped, but use of this modality to examine cruciate ligaments remains difficult because of the orientation and deep anatomic location of these structures.
- CT using contrast arthrography has been used to image the stifle, but limitations exist to its availability and the availability of MRI.
But not since the introduction of the needleoscopy modality and the NeedleView® 1.2mm arthroscope. With it, standing diagnostic arthroscopy is an outpatient standing procedure that offers:
- Early detection and conclusive diagnosis of joint problems
- Timely intervention
- Shortened rehab and better patient outcomes
- Higher owner/trainer compliance
Standing diagnostic arthroscopy with the NeedleView Arthroscope Suite does have some limitations, however, in that the size of the scope allows for only certain therapeutic interventions, and there is the potential for additional procedures (for example, when standing diagnostic arthroscopy indicates a definitive need for a more invasive surgery).
Capabilities Proven By Both Research And Practice
In a seminal peer-reviewed study1 published in 2014, researchers confirmed:
- The 18-gauge NeedleView arthroscope can be used to perform complete diagnostic examination of the three compartments of the stifle joint in standing horses.
- In areas of the joint where space was limited, the small diameter of the scope was an advantage despite the smaller field of view.
Since publication, one of the study’s lead authors (David Frisbie, DVM, PhD, MS, DACVS, DACVSMR, Professor of Equine Surgery, Colorado State University, Fort Collins, CO) has successfully used the needleoscopy modality and NeedleView arthroscope to diagnose injuries in hundreds of stifles, including:
- Meniscal tears and lesions
- Cartilage damage
- Cruciate ligament tears and lesions
- Floating joint fragments
- Subchondral bone cysts
Needleoscopy can also be used to confirm the presence of a lesion identified by either x-rays or ultrasound and confirm that no additional lesions are present.
Another study2 in 2015 concluded: “When combined, arthroscopy and ultrasound can provide a more global assessment of pathological changes within the equine stifle.”
Capabilities Beyond the Stifle
And it’s not limited to the stifle. Recently-published studies have found novel applications for the needleoscopy modality and NeedleView, including:
- Navicular bursa: A 2015 study³ explored direct and transthecal approaches to the navicular bursa using Biovision’s NeedleView scope. Among its conclusions: “Needle endoscopy offers a reliable technique to evaluate the navicular bursa and may complement or replace other diagnostic modalities in horses with lameness localized to the navicular region.”
- Paranasal sinus: A 2020 study4 explored the use of Biovision’s NeedleView camera in conjunction with a 2mm flexible endoscope for standing, conscious evaluation of the paranasal sinus. The conclusion: “Minimally invasive sinuscopy was readily performed without relevant complications in standing horses. A thorough evaluation of most sinus structures was obtained only using the frontal and the rostral maxillary portals.”
- Fetlock: This 2019 prospective clinical study5 described the technique, experience and outcome of standing, conscious arthroscopic removal of dorsal osteochondral fragmentation of the metacarpophalangeal and metatarsophalangeal joint using Biovision’s 1.2-mm NeedleView arthroscope. The conclusion: “All fragments were successfully removed and needle arthroscopy allowed a thorough evaluation of the dorsal aspect of the joint. The technique offers an alternative for standing fetlock arthroscopy for surgeons concerned about equipment damage or portability.”
- Caudal cervical articular process joints: In this 2020 prospective experimental case series6, six adult horses were left standing and sedated in stocks. The trocar and cannula assembly under ultrasound guidance without joint distention and the NeedleView was introduced. Researchers explored bilateral C5-6 vertebral articular process joints in three of the horses; in the other three, bilateral C6-7 joints were examined. As reported in the paper:
- All 12 articular process joints were successfully explored.
- Entering the joint on the first attempt was achieved in 10 of 12 joints.
- A craniodorsal approach for arthroscope insertion allowed evaluation of the most cranial aspect of the articular cartilage surface.
As for limitations, researchers reported, “Triangulation with a spinal needle was determined to be difficult and resulted in a limited space for movement.” They concluded that needle arthroscopy of the caudal cervical facet joints can be performed safely and efficiently in standing sedated horses. The clinical significance, then, is that “Standing cervical articular process needle arthroscopy is a minimal morbidity technique with the potential to be an advantageous technique for the diagnosis and treatment of cervical articular process pathology.”
- Tarsocrural joint: In this 2020 experimental study7, researchers used cadaveric hind limbs in Phase 1 and six healthy horses in Phase 2, examining each tarsocrural joint (TCj) with the NeedleView scope and the use of a custom-made splint and base to maintain joint flexion during the procedure. As reported in the paper, “Thorough evaluation of the dorsal intra-articular structures of the TCj via dorsomedial and dorsolateral approaches was possible in both phases. The procedure was feasible, quickly performed, and well tolerated by all horses.” Dr. Bonilla and his coauthors concluded that “Diagnostic standing needle arthroscopy of the TCj allowed thorough evaluation of the dorsal aspect of the joint while avoiding the cost and risks associated with general anesthesia,” and “Needle arthroscopy of the TCj offers an alternative diagnostic tool when traditional imaging techniques (radiography and ultrasonography) are unrewarding or nondiagnostic.”
- Carpal sheath: Using six cadaveric limbs (forelimbs) in Phase 1 of this 2020 study8, the researchers performed carpal sheath tenoscopy with NeedleView using both the 65mm and 100mm scopes. This was followed by tenoscopy with a 4-mm arthroscope through a standard proximolateral approach. Using six healthy horses in Phase 2, they performed unilateral standing carpal sheath tenoscopy with the 65mm NeedleView scope, maintaining the limbs in flexion with a custom-made splint and base. As reported in the paper, “Visibility at the most distal aspect of the sheath was absent for the needle arthroscopes vs a standard arthroscope. The maneuverability with a 65-mm needle arthroscope was excellent and allowed exhaustive visualization of the proximal region of the carpal sheath in cadaveric limbs and standing horses (six of six). However, visualization of the intertendinous recess was partial in most horses (four of six) vs cadavers (complete in six of six) because of remaining flexor tendon tension in standing horses. No major complications were encountered.” The researchers concluded, “Standing carpal sheath tenoscopy allowed a safe and thorough evaluation of most structures in the proximal region of the sheath and offers an alternative diagnostic technique,” and “Horses with unrewarding results after traditional imaging or that require an accurate diagnosis before treatment may benefit from this alternative procedure.”
- Radiocarpal and middle carpal joints: Replicating the methods of the preceding two studies, Dr. Bonilla and his coauthors used NeedleView in cadaveric forelimbs as well as in healthy sedated standing horses to evaluate the radiocarpal and middle carpal joints in this 2020 study9. In Phase 1 (cadaveric), they were able to thoroughly evaluate the dorsal and palmar recesses of both joints with NeedleView. In phase 2 (standing sedated healthy horses), “…joint evaluation was also thorough but only dorsal approaches were performed. All horses underwent radiocarpal joint arthroscopy, whereas the middle carpal joint was evaluated in only three of six horses because of limb movement.” The researchers noted, “The technique was quickly performed and well tolerated by all horses. Complications included moderate movement, mild iatrogenic cartilage damage, and mild hemarthrosis.” They concluded, “Standing needle arthroscopy allowed thorough evaluation of the dorsal aspect of both joints, although only three of six middle carpal joints were assessed because of movement limitations,” and “The proposed technique offers an alternative diagnostic tool for radiographically silent intra-articular lesions of the carpus while initially avoiding the cost and risks associated with general anesthesia. Arthroscopy of a single joint is recommended to minimize risks associated with movement during the procedure.”
- Scapulohumeral joint: In this 2020 study10, the researchers sought to describe the technique for using needle arthroscopy to perform diagnostic standing scapulohumeral joint needle arthroscopy in horses. Using eight cadaveric thoracic limbs in Phase 1, they assessed the feasibility of the technique by using a craniolateral arthroscopic approach, performing an evaluation of the visible structures of the scapulohumeral joint with both NeedleView and a 4-mm arthroscope. In Phase 2, they performed the technique in six healthy sedated standing horses. As reported in the paper, “In phase 1, joint evaluation was similar between arthroscopes and allowed complete evaluation of approximately the lateral half of the humeral head and the lateral glenoid rim. In phase 2, all joints were successfully accessed, and fluid extravasation was mild. Arthroscopic visualization was complete for the centrolateral aspect of the joint in all horses and either complete (3/6) or partial (3/6) for the craniolateral and caudolateral structures, respectively. The procedure was rapidly performed and well tolerated, and no postoperative complications occurred.” The researchers concluded “The described technique was simple and allowed direct inspection of the scapulohumeral joint. Nonetheless, the standing nature of the technique prevents evaluation of the medial aspect of the humeral head and most of the glenoid cavity.” They added, “Needle arthroscopy of the scapulohumeral joint is feasible in horses and offers a diagnostic technique that may improve the surgeon's diagnostic ability for certain shoulder pathologies.”
1 Frisbie DD, Barrett MF, McIlwraith CW, and Ullmer J. Diagnostic stifle joint arthroscopy using a needle arthroscope in standing horses. Vet Surg. 2014 Jan;43(1):12-8. doi: 10.1111/j.1532-950X.2013.12068.x. Epub 2013 Oct 31.
2 Adrian AM, Barrett MF, Werpy NM, et al. A comparison of arthroscopy to ultrasonography for identification of pathology of the equine stifle. Equine Vet J. 2015 Nov 18. doi: 10.1111/evj.12541. [Epub ahead of print]
3 Mahlmann K, Koch C, and Bodo G. Diagnostic endoscopy of the navicular bursa using a needle endoscope by direct or transthecal approach: a comparative cadaver study. Vet Surg. 2015;44:816-824.
4 Pouyet M and Bonilla A. Validation of a 2-mm videoendoscope for the evaluation of the paranasal sinuses with a minimally invasive technique. Vet Surg. 2020 Jun;49 Suppl 1:O60-O70.
5 Bonilla, Alvaro G. Standing Needle Arthroscopy of the Metacarpophalangeal and Metatarsophalangeal Joint for Removal of Dorsal Osteochondral Fragmentation in 21 Horses. Veterinary and Comparative Orthopaedics and Traumatology, 2019, doi:10.1055/s-0039-1688984.
6 Evaluation of the caudal cervical articular process joints by using a needle arthroscope in standing horses. Vet. Surg. 2020; 49: 463-471. https://doi.org/10.1111/vsu.13388, , , .
7 Kadic DTN, Bonilla AG. Diagnostic needle arthroscopy of the tarsocrural joint in standing sedated horses. Vet Surg. 2020 Apr;49(3):445-454. doi: 10.1111/vsu.13375. Epub 2020 Jan 13.
8 Miagkoff L, Bonilla AG. Diagnostic tenoscopy of the carpal sheath with a needle arthroscope in standing sedated horses. Vet Surg. 2020 Jun;49 Suppl 1:O38-O44. doi: 10.1111/vsu.13381. Epub 2020 Jan 25.
9 Kadic DTN, Miagkoff L, Bonilla AG. Needle arthroscopy of the radiocarpal and middle carpal joints in standing sedated horses. Vet Surg. 2020 Jul;49(5):894-904. doi: 10.1111/vsu.13430. Epub 2020 Apr 25. PMID: 32333682
10 Pouyet M, Bonilla AG. Diagnostic needle arthroscopy of the scapulohumeral joint in standing sedated horses. Vet Surg. 2020 Oct 19. doi: 10.1111/vsu.13529. Online ahead of print.
From David Frisbie, DVM, PhD, MS, DACVS, DACVSMR, pioneer of standing stifle needle arthroscopy:
“Because of the NeedleView scope’s small size, we can ‘drive it around’ the stifle and image everything. No other technology gives us that ability. Traditional imaging modalities typically require transporting the animal and then putting it under general anesthesia and handling the subsequent recovery…all of which can be costly and may require significant lead time. The NeedleView Arthroscope Suite is so small and portable, we can perform diagnostic arthroscopy in our trailer at equine events. It truly lets us get an instant answer anywhere. We like that NeedleView gives us a way to diagnose mild to moderate stifle disease earlier in the process, before it has progressed too far to be amenable to treatment.”
One of the pioneers of therapeutic intervention using the NeedleView scope is Shane Miller, DVM, DACVS of Comstock Equine Hospital (Reno, NV), who says:
“I do a lot of stifle diagnostics, primarily because of my practice’s population and caseload. I also use it for exploration in areas like the tendon sheath, coffin, fetlock, and carpus. I even use it for sinuses to see masses, tumors, and fluid. I recently started using the NeedleView on horses that present with septic arthritis. The typical approach is to lay the horse down with general anesthesia and use a standard 4mm arthroscope to lavage or flush the joint. With the NeedleView, I can leave the horse standing and conscious but sedated, I can flush the joint, and I can generally get further into the joint than with a 4mm scope. If I see lots of fibrin deposition, I can put an instrument in from the other side – using the NeedleView to guide me – and pull it out. Whenever I can do an effective procedure without laying a horse down, it’s a win for the animal, the client, and me. When there’s no general anesthesia, there’s typically less morbidity and it’s almost always more cost-effective for the client. I’ve found that clients are more willing to move forward with the procedures – even if they are more expensive – if it means the horse can remain standing and conscious.”
In their own words: Equine Practitioners
- NeedleView Pioneer: David Frisbie, DVM, PhD, MS, DACVS, DACVSMR, Colorado State University Equine Orthopedic Research Center (Fort Collins, CO)
- NeedleView Researcher: Christoph Koch, Dr. Med. Vet., DACVS, DECVS, Swiss Institute of Equine Medicine (Bern, Switzerland)
- NeedleView Researcher: Barrie Grant, DVM, MS, DACVS, MRCVS, Barrie Grant Equine Consultant (Bonsall, CA)