Poster 157 Anatomical Relationship Between the Distal Transverse Carpal Ligament and the Hook of the Hamate: Implications for Ultrasound Guided Carpal Tunnel Release

Abstracts / PM R 8 (2016) S151-S332 RTP time (in days) by 17% (for males and females combined, IRR 1.17 , CI 1.00- 1.37). Conclusions: Risk assessment tools based on female athlete triad risk factors, and on similar risk factors in males, can predict RTP in collegiate distance runners who have sustained BSI. This is the first prospective outcome study assessing the TRIAD R-A for RTP, and a piloted risk assessment for male athletes with BSI. Further research assessing risk factors by incorporating a risk assessment tool into the RTP protocol in athletes is needed. Level of Evidence: Level III Poster 156 Synovial Osteochondromatosis as a Rare Cause of Hip Pain: A Case Report Melissa Pun, MD (Stanford, Sunnyvale, CA, United States), Eugene Y. Roh, MD Disclosures: Melissa Pun: I Have No Relevant Financial Relationships To Disclose Case/Program Description: A 49-year-old man presented to our clinic with chronic right hip pain for 15 years. Previously he was treated with analgesic medications, physical therapy, and corticosteroid injections without significant improvement. He had no history of trauma. Setting: Outpatient Musculoskeletal Clinic. Results: Physical examination showed tenderness to palpation over the right greater trochanter and iliopsoas muscle. He had decreased range of motion of the right hip with internal and external rotation. Radiography of the right hip joint revealed mild narrowing of the joint space and multiple small calcified bodies of different sizes. Magnetic resonance imaging (MRI) arthrogram of the right hip revealed multiple low signal loose bodies within the joint space, the largest measuring up to 2.1 centimeters. A limited bedside ultrasound showed multiple hyperechoic lesions with acoustic shadowing consistent with calcified nodules. These findings were consistent with synovial osteochondromatosis. The patient was then referred to an orthopedic surgeon for arthroscopic removal of the lesions. 15 days post-operatively, he had complete resolution of his right hip pain. Discussion: Symptoms of synovial osteochondromatosis in the hip are generally nonspecific, which makes diagnosis difficult in the early stages. Pain, swelling, and restricted range of motion are most commonly seen. Restriction of hip joint range of motion is associated with the mechanical effects of loose bodies in the joint space. Arthroscopic removal of the loose bodies properly treated synovial osteochondromatosis. Although this case was diagnosed radiographically, if our patient had presented with ambiguous findings, arthroscopy would have been useful to accurately diagnose synovial osteochondromatosis. Conclusions: Synovial osteochondromatosis can be difficult to diagnose as symptoms are often nonspecific. In advanced stages, the synovium may form osseous loose bodies that are detectable with advanced imaging. This makes early diagnosis difficult. It is important to keep synovial osteochondromatosis in mind during the evaluation of a patient with chronic and intractable hip pain. Level of Evidence: Level V Poster 157 Anatomical Relationship Between the Distal Transverse Carpal Ligament and the Hook of the Hamate: Implications for Ultrasound Guided Carpal Tunnel Release Jay Smith, MD (Mayo Clinic, Rochester, MN, United States), Terin Sytsma, MD, Holly Ryan, BA, Sanjeev Kakar, MD Disclosures: Jay Smith: Receipt of royalties - Tenex Health, Stock options or bond holdings - Tenex Health, Stock options or bond holdings - Sonex Health, Ownership or partnership - Sonex Health

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Objective: Ultrasound guided carpal tunnel release (UGCTR) may be a safe and effective alternative to traditional surgical approaches for refractory carpal tunnel syndrome. However, sonographic identification of the distal transverse carpal ligament (TCL) can be challenging. In comparison, the hook of the hamate (HH) is easily identifiable, but the relationship between the HH and the distal TCL has not been defined within the transverse safe zone (TSZ), where UGCTR is performed. The primary purpose of this study was to determine the anatomical relationships between the apex of the HH, distal TCL, and superficial palmar arch (SPA) at the ulnar and radial limits of the TSZ (ie, the ulnar and radial corridors). Design: Cadaveric study. Setting: Anatomy laboratory of an academic medical center. Participants: 20 un-embalmed cadaveric specimens ages 47 to 95 years. Interventions: Following dissection by a fellowship trained hand surgeon, electronic digital calipers were used to measure anatomical relationships with the wrist positioned for UGCTR. Main Outcome Measures: Distances between the apex of the HH and the distal TCL (HH-TCL) and the SPA (HH-SPA) within the ulnar and radial corridors of the TSZ. Results: HH-TCL averaged 11.1 mm (6.8-15.6 mm) in the ulnar corridor and 11.6 mm (7.3-18.2 mm) in the radial corridor (P ¼ .26), whereas HH-SPA averaged 13.4 mm (6.2-22.8 mm) in the ulnar corridor and 22.6 mm (18.0-28.4 mm) the radial corridor (P < .0001). Conclusions: During UGCTR, the HH may serve as a useful osseous landmark to identify the distal TCL, which is located an average of 11-12 mm (upper limit 18.2 mm) distally. UGCTR at the ulnar corridor of the TSZ may be more technically challenging due to a relatively small TCL-SPA distance. Level of Evidence: Level IV Poster 158 New-Onset Gout in a Young Adult Diagnosed Via Sonography: A Case Report Jonathan N. Finney, MD (University of Pittsburgh Medical Center, Glenshaw, PA, United States), Kentaro Onishi, DO Disclosures: Jonathan Finney: I Have No Relevant Financial Relationships To Disclose Case/Program Description: The patient presented to an emergency room (ER) with three days of acute-onset, atraumatic left lateral knee pain and swelling. He had no associated fever, chills, or malaise. Landmark-guided aspiration was attempted seven times by ER physicians, but was unsuccessful. Orthopedic consultants recovered hemorrhagic joint aspirate. Fluid studies and left knee MRI were ordered. MRI revealed extensive enhancement of subcutaneous area overlying the anterolateral knee. An infectious disease physician was subsequently consulted and deemed the enhancement not to be infectious. He was eventually discharged with diagnosis of spontaneous hemarthrosis. Pain persisted for weeks, and he was referred for diagnostic ultrasound. Examination revealed a limp, tenderness and swelling over lateral proximal patellar tendon. Sonography did not reveal joint effusion, but did identify a non-compressible, hyperemic subcutaneous mass with heterogenic consistency at proximal, lateral edge of patellar tendon. Using sonography, two milliliters of buffered 1% lidocaine were delivered to this hyperemic mass, which was then aspirated, recovering blood-tinged yellow fluid. Setting: Outpatient musculoskeletal clinic. Results: Studies of this subcutaneous fluid revealed uric acid crystals. Subsequent follow-up with a rheumatologist confirmed the diagnosis of gout. After anesthetic period, he noted marked improvement in pain, and he remained asymptomatic. Discussion: Subcutaneous tophus is a rare initial presentation of gout. Atraumatic knee swelling can be easily assumed to be intra-articular in nature. However, clinicians must recognize that subcutaneous swelling can clinically mimic joint effusion. Musculoskeletal ultrasound allows