Visualization of Volar Plate of the First Metatarsophalangeal Joint In Donor Cadavers and Healthy Volunteers using High-Resolution Musculoskeletal Probe

LAVERDIERE Cody1, Robert MOUSSELLI1, Brion BENNINGER1-9. Medical Anatomy Center1, Departments of Medical Anatomical Sciences2, Neuromuscular Medicine3, Family Practice4, Western University of Health Sciences, COMP–Northwest,... [ view full abstract ]

LAVERDIERE Cody1, Robert MOUSSELLI1, Brion BENNINGER1-9. Medical Anatomy Center1, Departments of Medical Anatomical Sciences2, Neuromuscular Medicine3, Family Practice4, Western University of Health Sciences, COMP–Northwest, Lebanon, OR. USA. Departments of Orthopaedics5, General Surgery6 and Sports Medicine7, Samaritan Health Services, Corvallis, OR. USA. Departments of Surgery8, Orthopaedics & Rehabilitation9, Oregon Health & Science University, Portland, OR. USA.

INTRODUCTION. First metatarsophalangeal (MTP) joint injuries significantly affect the standard and longevity of play by professional and aspiring amateur athletes. Work-related injuries affecting the 1st MTP joint causes significant debilitation and loss in work hours. The anatomy of this injury is not understood as well as it could be. The objective of this study was to assess whether the volar plate of the 1st MTP could be identified in cadavers and healthy volunteers using ultrasound (US) for volar plate anatomy. METHODS. Literature search was conducted to evaluate texts, atlases and journals regarding 1st MTP anatomy and ultrasound thereof. Classic 5-12 MHz, 18 MHz and SonicEye finger probes were used with Fukuda-Denshi and eSoate systems. Unembalmed (n=4sides), embalmed (n=20sides) and young healthy volunteers (n=68sides) were assessed. Ultrasound protocol consisted of palpating MTP joint, placing probe transversely, identify sesamoids, fan probe to identify joint space and volar plate. RESULTS. Literature search revealed no known studies. 2 medical students averaged 17/20 volar plate US acquisitions using a classic 5-12 MHz probe, 18/20 with SonicEye finger probe followed by dissection and 18/20 with 18 MHz probes (64/68 seen in live subjects). All volar plates were identified on unembalmed donors. DISCUSSION. Search revealed inconsistent anatomy and one study from one of the above authors using 5-12 MHz probe to identify volar plate. It was positive for a few studies using US to view the volar plate, however, no cadaver studies using 18 MHz probes. We understand the mechanism of injury resulting in turf toe or a hyperextended 1st MTP. Unfortunately, the anatomy is not well delineated around the great toe. CT/MRI scans are prohibitively expensive. This study successfully used variable US probes to identify the volar plate. An 18 MHz high resolution MSK probe and a finger probe appeared most successful. This may have been due to the shorter footplate crystal layout versus the longer footplate of the classic 5-12 MHz probe. CONCLUSION. This study demonstrated volar plate anatomy of the 1st MTP can be identified on cadavers and healthy volunteers using variable probes. This could lead to improved diagnosis and management.