MRI analysis of subtalar ligaments in the tarsal sinus has not been well performed. We retrospectively investigated the appearance of subtalar ligaments using 3D isotropic MRI and compared imaging findings of subtalar ligaments between patients with subtalar instability (STI) and controls. Preoperative MRIs of 23 STI patients treated with arthroscopic subtalar reconstruction were compared to MRIs of 23 age- and sex-matched control subjects without STI. Thickness and width of anterior capsular ligament (ACL) and interosseous talocalcaneal ligament (ITCL) as well as thickness of calcaneofibular ligament (CFL) and anterior talofibular ligament (ATFL) were measured. Abnormalities in ACL, ITCL, CFL, ATFL, cervical ligament, and inferior extensor retinaculum were analyzed. STI patients had significantly smaller ACL thickness and ACL width than controls (ACL thickness: 1.73 mm vs. 2.22 mm, p = 0.007; ACL width: 7.21 mm vs. 8.80 mm, p = 0.004). ACL thickness of ≤2.1 mm had a sensitivity of 66.7% and a specificity of 66.7% for diagnosis of STI. ACL width of ≤7.9 mm had a sensitivity of 80.0% and a specificity of 76.2% for the diagnosis of STI. However, thickness and width of ITCL, thickness of CFL, or thickness of ATFL was not significantly different between the two groups. Absence or complete tear of ACL was significantly more frequent in STI patients than that in controls (34.8% vs. 8.7%, p = 0.035). Complete tear of CFL and ATFL was more common in STI patients than that in controls, although the difference between the two groups was not statistically significant. Abnormalities of ITCL, cervical ligament, or inferior extensor retinaculum were not significantly different between the two groups. MRI features of thin or narrow ACLs may suggest STI. Absence or complete tear of ACL was significantly more common in STI patients than that in controls.

Objective: The purpose of this study was to assess the differences between subtalar instability (STI) and lateral ankle instability (LAI) focusing on subtalar ligaments using 3-dimensional (3D) isotropic magnetic resonance imaging (MRI).Methods: Preoperative MRIs of 10 patients with STI who failed nonoperative treatment and consequently underwent arthroscopic subtalar reconstruction were compared with preoperative MRIs of 23 patients with LAI who underwent ligament repair or reconstruction. Dimensions of anterior capsular ligament (ACL), interosseous talocalcaneal ligament (ITCL), calcaneofibular ligament (CFL), and anterior talofibular ligament (ATFL) were measured. Tears of ACL, ITCL, CFL, ATFL, cervical ligament, and inferior extensor retinaculum were analyzed.Results: Patients with subtalar instability had significantly lower ACL thickness and width than patients with LAI (thickness: 1.48 vs 2.12 mm,P= 0.045; width: 7.30 vs 8.64 mm,P= 0.029). An ACL thickness of 1.8 mm or less had sensitivity and specificity both at 75.0%, and an ACL width of 8 mm or less had sensitivity of 75.0% and specificity of 85.0% for discriminating STI from LAI. Absence or complete tear of ACL was more frequent in patients with STI than in patients with LAI (60.0% vs 13.0%,P= 0.010). The ATFL thickness was significantly greater in patients with LAI (P= 0.001). Complete tear of ATFL was more common in patients with LAI (P= 0.008). Complete tear of CFL was common in both the STI and LAI groups without significant difference (20.0% vs 21.7%). There was no significant difference in thickness and width of ITCL and in CFL thickness. Complete tear of ITCL, cervical ligament, and inferior extensor retinaculum were rare without significant difference.Conclusion: In patients with STI, the ACL is thin and narrow and more commonly absent or torn compared with patients with LAI. Complete tear of ATFL was more common in patients with LAI. Complete tear of CFL was commonly encountered in both the STI and LAI groups.

Objective: Primary frozen shoulder causes significant pain and progressively restricts shoulder movements. Diagnosis is primarily clinically based on patient history and physical examination. Management is mainly non-invasive owing to its self-limiting clinical course. However, clinical practice guidelines for frozen shoulder have not yet been developed in Korea. The developed guidelines aim to provide evidence-based recommendations for the diagnosis and treatment of frozen shoulder.Methods: A guideline development committee reviewed the literature from four databases (PubMed, Embase, Cochrane Library, and KMbase). Using the PICO (Population, Intervention, Comparator, and Outcome) framework, the committee formulated two backgrounds and 16 key questions to address common clinical concerns. Recommendations were made using the Grading of Recommendations, Assessment, Development, and Evaluation framework.Results: Diabetes, thyroid disease, and dyslipidemia significantly increase the risk of developing a frozen shoulder. Although frozen shoulder is often self-limiting, some patients may experience long-term disabilities. Ultrasound and magnetic resonance imaging should be used as adjunctive tools alongside clinical diagnosis, and not as independent diagnostic methods. Noninvasive approaches, such as medications, physical modalities, exercises, electrical stimulation, and manual therapy, may reduce pain and improve shoulder function. Other noninvasive interventions have limited evidence, and their application should be based on clinical judgment. Intra-articular steroid injections are recommended for treatment, and physiotherapy or hydrodilatation with steroid injections can also be beneficial.Conclusion: These guidelines provide evidence-based recommendations for diagnosing and treating primary frozen shoulder.

Background and Objectives: The aim of this study is to investigate the femoral tunnel geometry (femoral tunsnel location, femoral graft bending angle, and femoral tunnel length) on three-dimensional (3D) computed tomography (CT) and graft inclination on magnetic resonance imaging (MRI) after anatomic anterior cruciate ligament (ACL) reconstruction using a flexible reamer system. Materials and Methods: A total of 60 patients who underwent anatomical ACL reconstruction (ACLR) using a flexible reamer system were retrospectively reviewed. One day after the ACLR procedure was performed, all patients underwent three-dimensional computed tomography (3D-CT) and magnetic resonance imaging (MRI). The femoral tunnel location, femoral graft bending angle, femoral tunnel length, and graft inclination were assessed. Results: In the 3D-CTs, the femoral tunnel was located at 29.7 ± 4.4% in the posterior to anterior (deep to shallow) direction and at 24.1 ± 5.9% in the proximal to distal (high to low) direction. The mean femoral graft bending angle was 113.9 ± 5.7°, and the mean femoral tunnel length was 35.2 ± 3.1 mm. Posterior wall breakage was observed in five patients (8.3%). In the MRIs, the mean coronal graft inclination was 69.2 ± 4.7°, and the mean sagittal graft inclination was 52.4 ± 4.6°. The results of this study demonstrated that a comparable femoral graft bending angle and longer femoral tunnel length were observed compared with the reported outcomes from previous studies that used the rigid reamer system. Conclusions: ACLR using a flexible reamer system allowed for an anatomic femoral tunnel location and a comparable graft inclination to that of the native ACL. In addition, it achieved a tolerable femoral graft bending angle and femoral tunnel length.