Murine iPSC-Loaded Scaffold Grafts Improve Bone Regeneration in Critical-Size Bone Defects.

In certain situations, bones do not heal completely after fracturing. One of these situations is a critical-size bone defect where the bone cannot heal spontaneously. In such a case, complex fracture treatment over a long period of time is required, which carries a relevant risk of complications. The common methods used, such as autologous and allogeneic grafts, do not always lead to successful treatment results. Current approaches to increasing bone formation to bridge the gap include the application of stem cells on the fracture side. While most studies investigated the use of mesenchymal stromal cells, less evidence exists about induced pluripotent stem cells (iPSC). In this study, we investigated the potential of mouse iPSC-loaded scaffolds and decellularized scaffolds containing extracellular matrix from iPSCs for treating critical-size bone defects in a mouse model. In vitro differentiation followed by Alizarin Red staining and quantitative reverse transcription polymerase chain reaction confirmed the osteogenic differentiation potential of the iPSCs lines. Subsequently, an in vivo trial using a mouse model (n = 12) for critical-size bone defect was conducted, in which a PLGA/aCaP osteoconductive scaffold was transplanted into the bone defect for 9 weeks. Three groups (each n = 4) were defined as (1) osteoconductive scaffold only (control), (2) iPSC-derived extracellular matrix seeded on a scaffold and (3) iPSC seeded on a scaffold. Micro-CT and histological analysis show that iPSCs grafted onto an osteoconductive scaffold followed by induction of osteogenic differentiation resulted in significantly higher bone volume 9 weeks after implantation than an osteoconductive scaffold alone. Transplantation of iPSC-seeded PLGA/aCaP scaffolds may improve bone regeneration in critical-size bone defects in mice.

A novel radiological classification for displaced os coccyx: the Benditz-König classification.

BACKGROUND: Treatment of coccygodynia is still a challenging entity. Clear surgical selection criteria are still lacking. The aim of the investigation was to establish a novel radiological classification for surgical decision-making in coccygodynia cases. MATERIAL AND METHODS: Retrospective analysis of standing and sitting X-rays of coccygodynia patients referred to a single centre from 2018 to 2020. The sacro-coccygeal angle (SCA), the intra-coccygeal angle (ICA) and the difference of the intervertebral disc height (∆IDH) were measured. All coccyges were distributed in subtypes and correlated with the patients' treatment. RESULTS: In total, 138 patients (female/male: 103/35) with a mean age of 45.6 ± 15.4 years were included in the study. In total, 49 patients underwent coccygectomy. Four different subtypes of displaced coccyges were identified: Type I with a non-segmented coccyx, anterior pivot, increased SCA and ICA from standing to sitting, ∆IDH = 1.0 ± 1.5 mm. Type II with a multisegmented coccyx, anterior pivot, increased SCA and ICA standing/sitting, ∆IDH = 1.1 ± 1.6 mm. Type III showed a posterior pivoted coccyx, negative SCA and ICA, ∆IDH = 0.6 ± 1.6 mm. Type IV is characterized by an anterior-posterior dissociation of the tail bone with a positive SCA, and the ICA shifted from a posterior to an anterior orientation. ∆IDH was - 0.6 ± 1.8 mm. CONCLUSION: The presented radiological classification could help to facilitate the surgical decision-making for patients with displaced os coccyx. In addition, lateral and sitting X-rays were easy to perform and did not need unnecessary ionizing radiation like in CT scans and were more cost-effective than MRI investigations. The subtypes III and especially IV were more likely leading to surgery.

Hollow modular anchorage (HMA) screws for anterior transvertebral fixation in high-grade spondylolisthesis cases requiring 360 degrees in-situ fusion.

OBJECTIVE: 360 degrees in-situ fusion for high-grade spondylolisthesis showed satisfying clinical long-term results. Combining anterior with posterior surgery increases fusion rates. Anteriorly inserted transvertebral HMA screws could be an alternative to strut graft constructs or cages, avoiding donor site complications. In addition, complete posterior muscle detachment is avoided and the injury risk of neural structures is minimized. This study investigates the use of HMA screws in this context. MATERIAL AND METHODS: Five consecutive patients requiring L4-S1 in-situ fusion for isthmic spondylolisthesis (four Grade 3 and one Grade 4) were included. The L5/S1 level was fused with an HMA screw filled with local bone and bone morphogenic protein (BMP2), inserted via the L4/5 disc space level. An L4/5 stand-alone interbody fusion with additional minimal invasive posterior screw fixation was added. RESULTS: Transvertebral insertion of the HMA device was accomplished via a retroperitoneal approach to L4/L5 in all cases without exposure of L5/S1. Blood loss ranged from 150 ml-350 ml. No intraoperative complication occurred. One patient developed posterior wound infection requiring debridement. Solid fusion was confirmed with a CT scan after 6 months in all patients. All patients improved to unrestricted activities of daily living with two being limited by occasional back pain. CONCLUSIONS: HMA screws allow for effective lumbosacral fusion via a limited anterior exposure. This is technically easier than posterior exposure of the lumbosacral junction in high-grade spondylolisthesis requiring 360 degrees fusion.

The safe use of long screws in L5/S1 stand-alone anterior interbody fusion for olisthesis cases.

BACKGROUND: Stand-alone anterior interbody fusion (STALIF) with poly-ether-ether-ketone (PEEK) cages could offer a treatment option in olisthesis cases. The fixation of the PEEK-cage at the L5/S1 inferior endplate with long divergent screws however might endanger neural sacral structures, especially the S1 nerve root. If shorter screws are used, the achieved bony purchase might not be sufficient to resist the pull out and shear forces at the lumbosacral junction. The aim of the present investigation was to evaluate the use of long screws in PEEK-cages for olisthesis cases at the L5/S1 segment and its neurological complications. MATERIAL AND METHODS: 11 Patients (6 males) with a mean age of 47(± 15.1) years between 2013-2015 designated for an STALIF at the L5/S1 level were consecutively included in the present study. All patients had a Grade 1 or 2 slippage according to Meyerding. PEEK cages (SynFix-LR®, Depuy Synthes) were implanted with 30mm screws at the baseplate of L5/S1 in all patients. Perioperative and postoperative long-term complications were evaluated. Furthermore, radiological follow-up was performed (CT-scan at 6 months, X-ray at 6, 12 and 24 months). RESULTS: 6 patients suffered from an isthmic, 1 from a degenerative olisthesis. 4 patients with iatrogenic spondylolisthesis were included. Pre-operative radiculopathy was noted in 10 patients. 9 patients with pre-operative radiculopathy showed relief of symptoms until the last follow-up after 24 months. Fusion was achieved in all patients after 6 months. No screw-displacement, breakage or violation of the neural foramen was noted. Furthermore, no implant failure or pull-out fractures were seen. CONCLUSION: In this investigation, no complication due to the use of long divergent locking screws was noted. In addition, the majority of patients showed permanent relief of radiculopathy symptoms at the 2 years follow-up. This study demonstrates the safe usage of long divergent locking screws in the baseplate of L5/S1 in anterior interbody fusion at the L5/S1 level.

Direct transplantation of native pericytes from adipose tissue: A new perspective to stimulate healing in critical size bone defects.

BACKGROUND AIMS: Fractures with a critical size bone defect (e.g., open fracture with segmental bone loss) are associated with high rates of delayed union and non-union. The prevention and treatment of these complications remain a serious issue in trauma and orthopaedic surgery. Autologous cancellous bone grafting is a well-established and widely used technique. However, it has drawbacks related to availability, increased morbidity and insufficient efficacy. Mesenchymal stromal cells can potentially be used to improve fracture healing. In particular, human fat tissue has been identified as a good source of multilineage adipose-derived stem cells, which can be differentiated into osteoblasts. The main issue is that mesenchymal stromal cells are a heterogeneous population of progenitors and lineage-committed cells harboring a broad range of regenerative properties. This heterogeneity is also mirrored in the differentiation potential of these cells. In the present study, we sought to test the possibility to enrich defined subpopulations of stem/progenitor cells for direct therapeutic application without requiring an in vitro expansion. METHODS: We enriched a CD146+NG2+CD45- population of pericytes from freshly isolated stromal vascular fraction from mouse fat tissue and tested their osteogenic differentiation capacity in vitro and in vivo in a mouse model for critical size bone injury. RESULTS: Our results confirm the ability of enriched CD146+NG2+CD45- cells to efficiently generate osteoblasts in vitro, to colonize cancellous bone scaffolds and to successfully contribute to regeneration of large bone defects in vivo. CONCLUSIONS: This study represents proof of principle for the direct use of enriched populations of cells with stem/progenitor identity for therapeutic applications.

Distraction test of the posterior superior iliac spine (PSIS) in the diagnosis of sacroiliac joint arthropathy.

BACKGROUND: The sacroiliac joint (SIJ) is a frequently underestimated cause of lower back (LBP). A simple clinical test of sufficient validity would be desirable. The aim of this study was to evaluate the diagnostic value of a new PSIS distraction test for the clinical detection of SIJ arthropathy and to compare it to several commonly used clinical tests. METHODS: Consecutive patients, where a SIJ pathology had been confirmed by an SIJ infiltration were enrolled (case group, 61 SIJs in 46 patients). Before infiltration, patients were tested for pain with PSIS distraction by a punctual force on the PSIS in medial-to-lateral direction (PSIS distraction test), pain with pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber (or Patrick's) test. In addition, these clinical tests were applied to both SIJs of a population of individuals without history of LBP (control group, 64 SIJs in 32 patients). RESULTS: Within the investigated cohort, the PSIS distraction test showed a sensitivity of 100% and a specificity of 89% for SIJ pathology. The accuracy of the test was 94%, the positive predictive value (PPV) was 90% and the negative predictive value (NPV) was 100%. Pelvic compression, pelvic distraction, Gaenslen test, Thigh Thrust, and Faber test were associated with a good specificity (> 90%) but a poor sensitivity (< 35%). CONCLUSIONS: Within our population of patients with confirmed SIJ arthropathy the PSIS distraction test was found to be of high sensitivity, specificity and accuracy. In contrast, common clinical tests showed a poor sensitivity. The PSIS distraction test seems to be an easy-to-perform and clinically valuable test for SIJ arthropathy.

Kyphoplasty for lytic tumour lesions of the spine: prospective follow-up of 11 cases from procedure to death.

BACKGROUND: The life span of cancer patients has improved due to advancements in cancer management. With long survival periods, more patients show metastatic disease. Osteolytic tumours of spine are generated by metastatic deposits or primary tumours of the spine. A prospective study was performed to evaluate the efficacy and safety of percutaneous kyphoplasty in patients with osteolytic tumours of the thoracic and lumbar spine. MATERIALS AND METHODS: Eleven patients (age range 52-77/average 65 years; 7 female, 4 male) with osteolytic tumours of the spine were treated with kyphoplasty. The main Tokuhashi score was registered preoperatively. Outcome was assessed prospectively by visual analogue scale (VAS) for pain, ECOG performance status, walking distance, standing and sitting time. RESULTS: Preoperative VAS (average 7.5; range 2.6-10) dropped to 3.0, 5 days postoperatively and remained below 5 for follow-up. Main Tokuhashi score was 6.3, ranging from 3 to 9. Survival time ranged from 2 to 293 (average 74.4) weeks. Average walking distance, standing and sitting time and ECOG performance score showed improvement. All patients returned home and no patient required re-operation or readmission due to local disease progression or recurrence. CONCLUSION: Kyphoplasty is a suitable palliative treatment option for patients with advanced metastatic disease of the spine even with low Tokuhashi scores allowing rapid pain relief and mobilisation to increase the quality of life.

Curcumin-primed human BMSC-derived extracellular vesicles reverse IL-1ß-induced catabolic responses of OA chondrocytes by upregulating miR-126-3p.

BACKGROUND: Curcumin has anti-inflammatory effects and qualifies as a potential candidate for the treatment of osteoarthritis (OA). However, curcumin has limited bioavailability. Extracellular vesicles (EVs) are released by multiple cell types and act as molecule carrier during intercellular communication. We assume that EVs can maintain bioavailability and stability of curcumin after encapsulation. Here, we evaluated modulatory effects of curcumin-primed human (h)BMSC-derived EVs (Cur-EVs) on IL-1ß stimulated human osteoarthritic chondrocytes (OA-CH). METHODS: CellTiter-Blue Viability- (CTB), Caspase 3/7-, and live/dead assays were used to determine range of cytotoxic curcumin concentrations for hBMSC and OA-CH. Cur-EVs and control EVs were harvested from cell culture supernatants of hBMSC by ultracentrifugation. Western blotting (WB), transmission electron microscopy, and nanoparticle tracking analysis were performed to characterize the EVs. The intracellular incorporation of EVs derived from PHK26 labeled and curcumin-primed or control hBMSC was tested by adding the labeled EVs to OA-CH cultures. OA-CH were pre-stimulated with IL-1ß, followed by Cur-EV and control EV treatment for 24 h and subsequent analysis of viability, apoptosis, and migration (scratch assay). Relative expression of selected anabolic and catabolic genes was assessed with qRT-PCR. Furthermore, WB was performed to evaluate phosphorylation of Erk1/2, PI3K/Akt, and p38MAPK in OA-CH. The effect of hsa-miR-126-3p expression on IL-1ß-induced OA-CH was determined using CTB-, Caspase 3/7-, live/dead assays, and WB. RESULTS: Cur-EVs promoted viability and reduced apoptosis of IL-1ß-stimulated OA-CH and attenuated IL-1ß-induced inhibition of migration. Furthermore, Cur-EVs increased gene expression of BCL2, ACAN, SOX9, and COL2A1 and decreased gene expression of IL1B, IL6, MMP13, and COL10A1 in IL-1ß-stimulated OA-CH. In addition, phosphorylation of Erk1/2, PI3K/Akt, and p38 MAPK, induced by IL-1ß, is prevented by Cur-EVs. Cur-EVs increased IL-1ß-reduced expression of hsa-miR-126-3p and hsa-miR-126-3p mimic reversed the effects of IL-1ß. CONCLUSION: Cur-EVs alleviated IL-1ß-induced catabolic effects on OA-CH by promoting viability and migration, reducing apoptosis and phosphorylation of Erk1/2, PI3K/Akt, and p38 MAPK thereby modulating pro-inflammatory signaling pathways. Treatment of OA-CH with Cur-EVs is followed by upregulation of expression of hsa-miR-126-3p which is involved in modulation of anabolic response of OA-CH. EVs may be considered as promising drug delivery vehicles of curcumin helping to alleviate OA.

Hyperlordosis is Associated With Facet Joint Pathology at the Lower Lumbar Spine.

STUDY DESIGN: A retrospective study. OBJECTIVE: Our study opted to clarify the remaining issues of lumbar lordosis (LL) with regard to (1) its physiological values, (2) age, (3) sex, and (4) facet joint (FJ) arthritis and orientation using computed tomography (CT) scans. SUMMARY OF BACKGROUND DATA: Recent studies have questioned whether LL really decreases with age, but study sample sizes have been rather small and mostly been based on x-rays. As hyperlordosis increases the load transferred through the FJs, it seems plausible that hyperlordosis may lead to FJ arthritis at the lower lumbar spine. METHODS: We retrospectively analyzed the CT scans of 620 individuals, with a mean age of 42.5 (range, 14-94) years, who presented to our traumatology department and underwent a whole-body CT scan, between 2008 and 2010. LL was evaluated between the superior endplates of L1 and S1. FJs of the lumbar spine were evaluated for arthritis and orientation between L2 and S1. RESULTS: (1) The mean LL was 49.0 degrees (SD 11.1 degrees; range, 11.4-80.1 degrees). (2) LL increased with age and there was a significant difference in LL in our age groups (30 y and below, 31-50, 51-70, and ≥71 y and above) (P=0.02). (3) There was no significant difference in LL between females and males (50 and 49 degrees) (P=0.17). (4) LL showed a significant linear association with FJ arthritis [P=0.0026, OR=1.022 (1.008-1.036)] and sagittal FJ orientation at L5/S1 (P=0.001). In a logistic regression analysis, the cutoff point for LL was 49.4 degrees. CONCLUSIONS: This is the largest CT-based study on LL and FJs. LL significantly increases with age. As a novelty finding, hyperlordosis is significantly associated with FJ arthritis and sagittal FJ orientation at the lower lumbar spine. Thus, hyperlordosis may present with back pain and patients may benefit from surgical correction, for example, in the setting of trauma.

Influence of Vanadium 4+ and 5+ Ions on the Differentiation and Activation of Human Osteoclasts.

BACKGROUND: In the pathophysiology of implant failure, metal ions and inflammation-driven osteoclasts (OC) play a crucial role. The aim of this study was to investigate whether vanadium (V) ions induce differentiation of monocytic OC precursors into osteoresorptive multinucleated cells. In addition, the influence of V ions on the activation and function of in vitro generated OC was observed. METHODS: Human monocytes and osteoclasts were isolated from peripheral blood monocytic cells (PBMCs). Exposition with increasing concentrations (0-3 µM) of V4+/V5+ ions for 7 days followed. Assessment of OC differentiation, cell viability, and resorptional ability was performed by standard colorimetric cell viability assay 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenil)-2H-tetrazolium (MTS), tartrate-resistant acid phosphatase (TRAP) expression, and functional resorption assays on bone slides during a period of 21 days. RESULTS: No significant differences were noted between V4+/V5+ ions (p > 0.05). MTS showed significant reduction in cellular viability by V concentrations above 3 µM (p < 0.05). V concentrations above 0.5 µM showed negative effects on OC activation/differentiation. Higher V concentrations showed negative effects on resorptive function (all p < 0.05) without affecting cell viability. V4+/V5+ concentrations below 3 µM have negative effects on OC differentiation/function without affecting cell survival. CONCLUSION: Vanadium-containing implants may reduce implant failure rate by influencing osteoclast activity at the bone-implant interface. V-ligand complexes might offer new treatment options by accumulating in the bone.