In anatomic total shoulder arthroplasty (aTSA) research, postoperative anatomical measurements are often referenced to the reamed glenoid bone surface because the glenoid component is not fully visible on CT. However, the reliability of measurements based directly on the implant (implant-based method) and their agreement with the commonly used bone-based method remain unclear. In this study, CT scans from 29 patients undergoing primary aTSA were used to calculate postoperative glenoid positioning (translations, version, inclination) and HHS in the anterior-posterior (HHSAP) and superior-inferior (HHSSI) directions using both methods. The bone-based method referenced measurements to 3D postoperative scapular bone reconstructions, whereas the implant-based method used CT-registered digital glenoid component models. Inter- and intra-rater reliability of implant-based measurements were assessed using intraclass correlation coefficients (ICCs), and agreement between methods was evaluated using ICCs and Bland-Altman analyses. The implant-based approach demonstrated high inter- and intra-rater reliability (ICCs > 0.88), with minimal detectable changes below commonly cited clinical thresholds. The agreement between implant- and bone-based methods was moderate-to-excellent overall (ICC > 0.52), although significant bias and/or wide limits of agreement were observed for version, inclination, superior-inferior implant positioning, and HHSSI. Compared to implant-based measures, bone-based estimates showed a bias toward more superior implant positioning and superior HHSSI, greater retroversion, and more medialized implant positioning. In conclusion, direct implant-to-CT registration is a reliable method for 3D postoperative measurements after aTSA. Implant- and bone-based measurements can be used interchangeably for anterior-posterior implant positioning and HHSAP, but not for other measures when high precision is required. LEVEL OF EVIDENCE: Basic science study.

Two-stage temporomandibular joint (TMJ) arthroplasty may involve the placement of a spacer until a final prosthesis is placed. In cases where a patient is not immobilized via intermaxillary fixation (IMF), the spacer is considered to be articulating, and the patient can open their mouth and function more normally during this interval. This study was designed to retrospectively assess the volumetric changes of the spacer within the temporomandibular joint following the use of an articulating bone cement spacer in a two-stage reconstruction. Fourteen patients (thirteen females, one male with mean ± SD age of 58.1 ± 13.0 years underwent two-stage TMJ reconstruction with an articulating spacer. The mean duration of the spacer retention was 142.1 ± 58.4 days. The median volume change of the temporomandibular joint spacer was quantified. Longer retention of the spacer was significantly associated with greater volume change (P = 0.011). There was no impact on prosthesis fit or occlusion at the time of surgery, and prosthesis outcomes were good. This study indicates that the duration of retention of the articulating bone cement spacer in the TMJ influences the amount of spacer volumetric changes, although the amount of change does not appear to be clinically significant.

Fear-related psychological barriers are increasingly recognized contributors to persistent pain, functional limitation, and dissatisfaction following total hip and knee arthroplasty. This systematic review synthesizes evidence on fear-related constructs and postoperative recovery and introduces the FEAR Framework as a structured model for clinical interpretation. This review (1) summarizes associations between fear-related constructs and postoperative outcomes; (2) organizes these constructs into four domains: Fall Confidence, Exposure Avoidance, Anticipatory Anxiety, and Reinjury Fear; (3) reviews validated patient-reported outcome measures; and (4) discusses clinical applications of FEAR-based assessment. Fear-related factors, particularly kinesiophobia and pain catastrophizing, are consistently associated with worse outcomes after arthroplasty. The FEAR Framework may provide a practical method for identifying modifiable psychological barriers and may help distinguish non-mechanical contributors to discordant recovery.

Total knee arthroplasty (TKA) success is highly dependent on accurate implant alignment, however, 80% of procedures globally are performed manually. Manual procedures have higher alignment errors compared to robotic platforms and patient-specific instrumentation, yet these have limitations of high cost and intraoperative inflexibility, respectively. This study aimed to evaluate the intraoperative pin positioning accuracy and flexibility of a smartphone-assisted navigation system using CT-derived surgical plans. Three participants used the navigation system to perform 108 guide pin insertions (54 femoral, 54 tibial) on surrogate bone models based on CT-derived surgical plans. Testing included both default mechanical axis targets (0°) and user-selected navigated targets ranging from -3° to 3°. Accuracy was assessed by comparing achieved pin trajectories with the preoperative surgical plan. Median absolute angular deviations achieved ranged from 0.9° to 1.6° across all component-plane combinations, with an overall median deviation of 1.3° (IQR 0.6-2.1°). The proportion of insertions within a predefined ±3° clinical accuracy threshold ranged from 83.3% to 100%, and all component-plane combinations demonstrated deviations significantly within this threshold (p < 0.00001). These findings support the technical feasibility of the smartphone-assisted navigation system for surgical pin positioning under controlled pre-clinical conditions. Further studies will evaluate the navigation system in cadaveric models with experienced orthopaedic surgeon participants.

Osteoarthritis (OA) is a leading cause of joint pain and functional limitations in the elderly. Conventional imaging methods, including weight-bearing radiography (WB-XR), non-weight-bearing CT, and MRI, provide valuable structural information but cannot fully characterize three-dimensional joint morphology and biomechanical changes under physiological loading conditions. Weight-bearing cone-beam computed tomography (WBCT) has emerged as a functional imaging modality that integrates three-dimensional imaging with weight-bearing acquisition, enabling comprehensive evaluation of lower-limb alignment, rotational relationships, joint congruity, and joint space distribution. By combining the advantages of WB-XR and three-dimensional CT assessment in a single examination, WBCT provides a potential single-stop imaging workflow with improved efficiency and reduced need for multiple imaging procedures. Recent advances in quantitative analysis, including three-dimensional biometrics, distance and coverage mapping, and bone density assessment, have further expanded its applications in hip, knee, and foot/ankle osteoarthritis, as well as perioperative evaluation of alignment-correcting procedures and joint arthroplasty. Although WBCT demonstrates substantial value for osseous and biomechanical assessment, further studies are required to optimize acquisition protocols, validate quantitative biomarkers, and establish its role in longitudinal disease monitoring and personalized management of osteoarthritis.

The aim of this study was to analyze the risk factors of postoperative delirium in elderly hip arthroplasty patients and to construct and validate a nomogram model. The clinical data of elderly patients with hip arthroplasty admitted to our hospital from January 2022 to December 2023 were retrospectively collected. Univariate and multivariate logistic regression analyses were used to determine the independent risk factors for delirium risk after hip arthroplasty in elderly patients, and the corresponding nomogram was established. Receiver operating characteristic curves and calibration curves were plotted to assess model performance. To further improve the reliability of the validation results, internal validation was performed using Bootstrap combined with 10-fold cross-validation rows to assess the clinical utility of the model using decision curve analysis. A total of 427 elderly hip replacement patients were enrolled in the study, and 74 patients experienced postoperative delirium, with an incidence rate of 17.33%. After univariate and multivariate logistic regression analyses, a total of 5 variables were identified as independent risk factors for postoperative delirium in elderly patients with hip arthroplasty: age >75 years (odds ratio [OR], 4.042; 95% confidence interval [CI], 2.129-8.244), cardiovascular disease (OR, 2.887; 95% CI, 1.584-5.347), duration of surgery >90 minutes (OR, 3.112; 95% CI, 1.118-6.839), resuscitation time >60 minutes (OR, 5.099; 95% CI, 2.632-9.837) and postoperative hypoxemia (OR, 4.244; 95% CI, 1.633-7.986). The nomogram constructed in this study for the risk of postoperative delirium in elderly patients with hip arthroplasty has good predictive accuracy and helps physicians to intervene in advance in elderly patients at high risk of postoperative delirium after hip arthroplasty.