Journal of Orthopaedic Research®最新文献

Calcific tendinopathy is a common musculoskeletal disorder marked by calcium deposition within tendons, often accompanied by pain, impaired mobility, and in severe cases, ossification. However, the mechanisms underlying tendon mineralization remain poorly understood. In contrast to pathological human calcification, turkeys naturally develop tendon mineralization during growth without signs of inflammation or ossification. This study had two phases: an observational phase to assess onset and progression of calcification, and an interventional phase to evaluate the role of mechanical loading. In the observational phase, flexor tendons were collected from turkeys aged 1–16 weeks in a serial sacrifice study and analyzed by Von Kossa staining and biomechanical testing. Calcification began at 7 weeks, localized within organized collagen matrices, progressed through Weeks 8–14, and peaked by 16 weeks. In the interventional phase, nine female turkeys were randomized at 4 weeks into a transection group (n = 3), sham group (n = 3), and control group (n = 3). Transection at the muscle–tendon junction eliminated mechanical loading. At 16 weeks, tendons were analyzed by histology, quantitative RT-PCR, ICP-MS, and biomechanical testing. Transected tendons showed a near-complete absence of mineralization, reduced expression of osteogenic markers (osteopontin, osteocalcin, Runx-2), and significantly lower calcium, magnesium, and phosphorus levels. Biomechanical testing indicated reduced stress relaxation, stiffness, and Young's modulus in the transected group. Tendon calcification in turkeys functioned as a mechanically regulated, nonpathological process. The study established a relevant model for early tendon mineralization and offered a basis for developing load-dependent therapies for human tendon disease.

Raman spectroscopy is a molecular fingerprinting technique that uses inelastic light scattering to characterize material composition and has been widely applied to bone quality assessment. In this ex vivo feasibility study, we tested whether Raman spectroscopy could predict femoral neck T-scores (n = 58) from specimens obtained during elective total hip arthroplasty and classify them as normal, osteopenic, or osteoporotic. Bone samples were excited using a near-infrared, multiple spatial mode, semiconductor laser (830 nm, 150 mW), and scattered light was collected for spectral analysis. Custom MATLAB code calculated Raman outcomes. T-scores were determined from bone mineral density acquired from dual-energy X-ray absorptiometry. Raman components were correlated with T-score using simple linear or partial least squares regressions (PLSR). Bone health classifications were assessed through receiver operating characteristic curves (ROC), area under the ROC curves (AUC), and descriptive statistics. Simple linear regression models identified mineral maturity/crystallinity (MMC) as the strongest single-variable predictor of T-score in males (R² = 0.20, 95% CI 0.00–0.43) and females (R² = 0.22, 95% CI 0.00–0.46). MMC showed fair discrimination between normal and osteopenic or osteoporotic groups in males (AUC = 0.76, 95% CI 0.56–0.97; 0.77, 95% CI 0.55–0.99) and females (AUC = 0.73, 95% CI 0.52–0.95; 0.70, 95% CI 0.47–0.92). PLSR (including mineral-to-matrix ratio, carbonate-to-phosphate ratio, MMC, and pyridinoline) slightly improved combined sex T-score correlation (R² = 0.28, 95% CI 0.05–0.55) and male normal versus osteoporotic classification (AUC = 0.89, 95% CI 0.75–1.00). This ex vivo feasibility study demonstrates the potential of Raman spectroscopy to differentiate bone quality.

This prospective study evaluated the long-term efficacy, radiographic progression, and predictors of deterioration in patients with knee osteoarthritis (KOA) treated with intra-articular platelet-rich plasma (PRP) injections. Seventy-eight patients (118 knees) with Kellgren–Lawrence (KL) grade I–III KOA received 3 monthly PRP injections and were followed at 4 and 6 years. Pain and function were assessed with the Visual Analogue Scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Radiographic progression, analgesic use, and predictors of clinical worsening were analysed using linear mixed-effects modeling and survival analysis. At 4 years, significant improvements were observed in VAS (6.72 ± 1.82 to 4.47 ± 1.32, p < 0.0001) and WOMAC (58.32 ± 17.58 to 39.67 ± 10.37, p < 0.0001). By 6 years, outcomes regressed toward baseline (VAS 6.31 ± 1.47, p = 0.079; WOMAC 56.45 ± 14.35, p = 0.41). Benefits were more sustained in KL I–II compared with KL III, who showed earlier decline and greater analgesic use. KL progression was the strongest predictor of worsening (β = +14.2 WOMAC points, p < 0.001), with each baseline KL grade increase adding +6.5 WOMAC points (p = 0.002); BMI also contributed modestly (p = 0.018). Survival analysis showed KL III had a 3.1-fold higher failure risk than KL I (median 3.5 vs. 5.1 years, p < 0.001). PRP provides meaningful symptom relief and functional improvement for up to 4 years in mild-to-moderate KOA, but benefits decline by 6 years, particularly in advanced disease.

Short-stem humeral implants in reverse total shoulder arthroplasty (rTSA) are increasingly adopted because they preserve bone stock and reduce stress shielding. However, their shorter length raises the risk of malalignment, and outcomes may be further affected by osteoporosis, which is common in rTSA patients. This study investigated how humeral stem alignment (neutral, varus, valgus) and bone mineral density simultaneously influence stress distribution in the proximal humerus using finite element (FE) analysis. FE models were developed from computed tomography scans of one normal and one osteoporotic humerus. A curved short stem was virtually implanted in three alignments, and physiological loading was applied. Von Mises stress was examined in cortical and trabecular bone, subdivided into medial/lateral and proximal/distal regions. Varus alignment produced the largest stress reduction in the proximal-lateral region, particularly in osteoporotic bone (up to −55.5%). Valgus alignment reduced stress primarily in the proximal-medial region (up to −55.9%) but also affected the proximal-lateral region. These results confirm that malalignment induces stress shielding patterns consistent with clinically observed bone resorption. Specifically, varus alignment was associated with shielding in the proximal-lateral region, whereas valgus alignment contributed to reductions in both proximal-medial and lateral regions. In osteoporotic bone, malalignment exacerbated stress shielding, with varus demonstrating the most detrimental effect.

Clinical Significance: These findings highlight the importance of stem alignment to minimize proximal stress shielding, especially in osteoporotic patients. Careful intraoperative positioning may reduce adverse mechanical outcomes, though further clinical studies are required to establish definitive surgical guidelines.

Achieving acetabular cup stability following revision total hip arthroplasty (rTHA) involving acetabular defects is challenging. Current computational modeling approaches to investigate implant stability under physiological loading are time consuming to implement and, to date, have been based on low sample sizes across limited defect classifications. This study had two aims. First, to develop an automated rTHA simulation framework to estimate postoperative implant response to physiological loading across the range of Paprosky acetabular defects; and second, to use this framework to estimate regional implant stability and osseointegration potential of rTHA implants augmented with four different screw configurations: (i) superior fixation only (ii) superior and infero-posterior fixation (iii) superior and infero-anterior fixation, and (iv) superior, infero-posterior, and infero-anterior fixation. A modeling pipeline employing artificial neural networks and statistical shape modeling was developed to convert patient computed tomography (CT) images to finite element models for automated surgical planning and simulation of rTHA involving acetabular defects. Computed tomography images from sixty subjects were used as input to the framework resulting in 214 completed simulations. An infero-posterior screw when used with a superior screw was associated with a significant reduction in posterior acetabular micromotion compared to using a superior screw alone (mean reduction: 129 μm, p < 0.001). Use of an infero-posterior screw improved overall implant stability more than that of an infero-anterior screw. The results suggest that screw holes allowing inferior fixation ought to be made standard in revision acetabular components. The findings of this study may be useful in surgical planning for rTHA.