Purpose: Segmental instability guides surgical decision-making in isthmic lumbar spondylolisthesis (ILS). Despite concerns regarding radiation exposure, reproducibility and applicability in patients with pain or limited mobility, flexion–extension (FE) radiographs remain the standard for instability assessment. Combining upright radiographs with supine magnetic resonance imaging (MRI), both routinely obtained in clinical practice, may offer a comparable, lower-radiation alternative. This study aimed to compare segmental motion at L5/S1 between FE and upright–supine (US) imaging and to evaluate their ability to detect radiographic instability. Methods: In this retrospective cross-sectional study, consecutive patients surgically treated for isolated L5/S1 ILS were screened for eligibility. Segmental motion was assessed using FE radiographs and US imaging, including measurements of dynamic sagittal translation and the proportion of patients identified with radiographic signs of instability. Preoperative pain intensity was assessed using the Numeric Rating Scale (NRS). Results: Of 126 screened patients, 78 met inclusion criteria (59% female; median age 48.5 years; median BMI 26.4 kg/m²). Dynamic sagittal translation was significantly greater on US than on FE ( p < 0.001). US imaging identified more cases of radiographic instability ( p < 0.001). Only US-measured translation was associated with preoperative low back pain intensity ( p = 0.025) and was inversely associated with intervertebral disc degeneration ( p = 0.014). Conclusions: US imaging detected a higher proportion of radiographically unstable ILS cases than FE radiographs. Furthermore, only US-derived translation was associated with pain intensity, suggesting greater clinical relevance. Combining upright radiographs with supine MRI may offer a practical, low-radiation alternative for preoperative instability assessment.

Degenerative lumbar spondylolisthesis (DLS) is a major indication for lumbar surgery. Surgical decision-making, particularly regarding the need for fusion, often depends on radiographic detection of segmental instability. Flexion–extension (FE) radiographs remain the reference standard but are limited by radiation exposure, motion-related discomfort, and poor reproducibility, whereas upright–supine (US) imaging - combining upright lateral radiographs with supine MRI - may offer a comparable, low-radiation alternative using routinely acquired images. To compare segmental motion at L4/5 between FE and US imaging and evaluate their respective abilities to identify patients with radiographic signs of instability. In this retrospective cross-sectional study, 128 patients surgically treated for isolated L4/5 DLS were included. Segmental motion was analyzed using FE and US imaging by determining relative slippage, dynamic slip angle, and radiographic instability, defined as sagittal translation ≥8% and/or a dynamic slip angle ≥10°. Relative slippage was comparable between US and FE imaging (US: 7.43 ± 5.10%; FE: 7.29 ± 4.57%; p = 0.994). The dynamic slip angle was significantly higher in US imaging compared to FE imaging (US: 6.42 ± 4.20°; FE: 4.03 ± 2.98°; p < 0.001). US imaging identified more patients with radiographic signs of instability compared to FE imaging (US: n = 68, 53.1%; FE: n = 42, 32.8%; p < 0.001). US imaging identified a higher proportion of patients meeting established thresholds for radiographic instability compared to FE radiographs. Although FE imaging remains the diagnostic standard, US imaging may offer a practical, low-radiation alternative for preoperative assessment. Prospective investigations are warranted to confirm its clinical utility.

Social media has become a major source of health information. TikTok, a rapidly expanding global platform that enables broad dissemination of medical content, yet the accuracy and reliability of such information remain uncertain. In this context, assessing the educational quality of videos on spondylolisthesis is of increasing clinical relevance. To evaluate the quality, reliability, and educational value of TikTok videos on spondylolisthesis and identify factors associated with higher-quality content. TikTok was searched in August 2025 using the keyword “spondylolisthesis.” Video metrics, uploader type and content category were recorded. Two orthopedic surgeons independently assessed reliability and quality using the DISCERN tool, Journal of the American Medical Association (JAMA) benchmarks, and Global Quality Score (GQS). A total of 254 TikTok videos were screened, of which 82 met inclusion criteria, totaling 4.15 million views and 55,967 likes. Private users uploaded 46.3%, surgeons 28.0%, physiotherapists 23.2%, and researchers 2.4%. Overall quality was poor (DISCERN 34.1 ± 17.6; JAMA 1.8 ± 1.1; GQS 2.6 ± 1.1). Videos by surgeons and physiotherapists scored significantly higher (p < 0.001), and educational content outperformed patient experiences (p < 0.001). Longer videos correlated with higher quality scores, while engagement metrics were not predictive. Most TikTok videos on spondylolisthesis showed low quality and limited reliability. Educational content produced by healthcare professionals performed better, while popularity metrics were not indicative of quality. Spine specialists should recognize TikTok's growing role in patient education and contribute accurate, evidence-based content to improve information quality.

Purpose: The posterior tibial plateau offset (PTPO) is a parameter of sagittal plane bony tibia morphology with high variability and clinical relevance, particularly in cases involving stemmed tibial implants, where posterior tibial cortex interference may occur. However, its change during total knee arthroplasty (TKA), and its relationship to tibial component positioning remain unknown. Methods: Pre- and postoperative sagittal radiographs of 98 patients undergoing primary, mechanically aligned TKA using a single implant system were retrospectively analyzed. PTPO was measured as the distance between the tibial anatomical axis and the center of the tibial plateau or tibial component. Tibial component placement (TCP) was assessed anteriorly and posteriorly and categorized as anatomical (0–1 mm), mild (1–3 mm), or moderate (>3 mm) underhang (TCU) or overhang (TCO). Pre- and postoperative changes in PTPO were analyzed, preoperative PTPO was compared across TCP categories. Correlations with absolute anterior and posterior deviation from anatomical component placements were calculated. Results: PTPO showed high preoperative variability (mean 6.89 ± 3.69 mm) and was significantly reduced after TKA (5.89 ± 3.44 mm; mean change −1.06 ± 3.44 mm; p < 0.001). Higher preoperative PTPO was associated with anterior (p = 0.01) and posterior TCU (p = 0.02). PTPO showed a moderate correlation with anterior (r = 0.53, p < 0.01) and a strong correlation with posterior implant deviation (r = 0.68, p < 0.01). Conclusions: PTPO shows high variability among patients undergoing TKA, is significantly altered through surgery and correlates with tibial component malposition, particularly TCU. Surgeons should consider PTPO during preoperative planning to optimize tibial component positioning and reduce the risk of implant-to-bone conflict, especially when using stemmed implants. In patients with a high preoperative PTPO, accuracy-enhancing techniques such as computer navigation or robotic assistance may be considered.

Introduction: Isthmic lumbar spondylolisthesis (ILS) results from a defect of the pars interarticularis, leading to anterior vertebral displacement. We hypothesize that paraspinal muscle atrophy contributes to the degree of vertebral slippage in symptomatic ILS. Methods: This retrospective cross-sectional study included 78 patients (46 females, 32 males). Fat infiltration (FI) and height-adjusted functional cross-sectional area (HI) of the multifidus (MF), erector spinae (ES), and psoas (PS) muscles were quantified applying the Otsu thresholding method. Multivariable linear regression was used to analysis the association between the paraspinal musculature and vertebral slippage. Confounding variables such as sex, age, body mass index (BMI), disc (Pfirrmann classification) and facet joints degeneration (Weishaupt classification) were included. Results: The median age was 48.5 (interquartile range [IQR]: 31.5–55) years, median BMI was 26.4 (IQR: 22.8–29.4) kg/m², and the median translation was 33 (IQR: 24–47) %. After adjustment for demographic confounders and degeneration, the MF atrophy showed significant association with vertebral slippage (FI: η² = 0.164, p < 0.001; HI: η² = 0.052, p = 0.028). In contrast, no significant associations were observed for the ES (FI: η² = 0.012, p = 0.315; HI: η² = 0.000, p = 0.936) or PS (FI: η² = 0.001, p = 0.742; HI: η² = 0.000, p = 0.979) muscles. Conclusion: The degree of vertebral slippage in isthmic lumbar spondylolisthesis was specifically associated with multifidus atrophy, while other paraspinal muscles showed no such relationship. These results support the distinct biomechanical role of the multifidus in segmental stability.