Imaging evaluation of extraarticular posterior loose bodies in varus ankle osteoarthritis

• Published in: Journal of orthopaedic surgery (Hong Kong) Vol. 32; no. 3; p. 10225536241284507
• Main Authors: Song, Tae Hun, Choi, Jun Young, Suh, Jin Soo, Suh, Yu Min, Chun, Kyung Ah
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.09.2024; Sage Publications Ltd; SAGE Publishing
• Subjects: Adult; Aged; Ankle; Ankle Joint - diagnostic imaging; Ankle Joint - pathology; Ankle Joint - surgery; Female; Humans; Joint Loose Bodies - diagnostic imaging; Joint Loose Bodies - surgery; Magnetic Resonance Imaging; Male; Middle Aged; Osteoarthritis; Osteoarthritis - diagnostic imaging; Osteoarthritis - surgery; Retrospective Studies; Tomography, X-Ray Computed; osteochondral fragment; arthritis; synovial chondromatosis; loose body; ankle
• ISSN: 1022-5536; 2309-4990; 2309-4990
• DOI: 10.1177/10225536241284507

Purpose: Multiple loose bodies (LBs) are often found in patients with varus ankle osteoarthritis (OA). This study aimed to investigate the characteristics of extra-articular posterior ankle LBs in patients with varus ankle OA. We also sought to determine whether there were variations in the characteristics of LBs according to the degree of ankle OA. Methods: We retrospectively reviewed 50 patients who had appeared posterior extraarticular LBs on preoperative ankle imaging among the patients who underwent operative treatment for varus ankle OA from March 2011 to February 2023. We categorized the entire patient cohort into four groups according to the degree of ankle arthritis (Takakura stage II, IIIA, IIIB, and IV). Size, number, and location of LBs were evaluated using preoperative computed tomography and magnetic resonance imaging. Results: 142 LBs were identified (mean size: 11.5 mm); 76.8% were located within the flexor hallucis longus (FHL) tendon sheath, 20.4% in the posterior recess, and 2.8% in the flexor digitorum longus tendon sheath. Average LB size was significantly larger in Takakura stage IIIB and IV patients (p < .05), and the LB number was significantly lower in stage II patients (p = .013). Conclusion: Extra-articular posterior LBs in varus ankle OA are predominantly located within the FHL tendon sheath and were larger in Takakura stages IIIB and IV patients. Level of Evidence: Level III. Retrospective comparative study.