Bone marrow in orthopaedics (part II): a three hundred and seventy million-year saga from the Devonian to the coronavirus disease 2019 pandemic-osteonecrosis; transplantation; "human chimera"; stem cells, bioreactors, and coronavirus disease

Mesenchymal Stem Cell Therapy for Bone Repair of Human Hip Osteonecrosis with Bilateral Match-Control Evaluation: Impact of Tissue Source, Cell Count, Disease Stage, and Volume Size on 908 Hips

We investigated the impact of mesenchymal stem cell (MSC) therapy on treating bilateral human hip osteonecrosis, analyzing 908 cases. This study assesses factors such as tissue source and cell count, comparing core decompression with various cell therapies. This research emphasizes bone repair according to pre-treatment conditions and the specificities of cell therapy in osteonecrosis repair, indicating a potential for improved bone repair strategies in hips without femoral head collapse. This study utilized a single-center retrospective analysis to investigate the efficacy of cellular approaches in the bone repair of osteonecrosis. It examined the impact on bone repair of tissue source (autologous bone marrow concentrate, allogeneic expanded, autologous expanded), cell quantity (from none in core decompression alone to millions in cell therapy), and osteonecrosis stage and volume. Excluding hips with femoral head collapse, it focused on patients who had bilateral hip osteonecrosis, both pre-operative and post-operative MRIs, and a follow-up of over five years. The analysis divided these patients into seven groups based on match control treatment variations in bilateral hip osteonecrosis, primarily investigating the outcomes between core decompression, washing effect, and different tissue sources of MSCs. Younger patients (<30 years) demonstrated significantly better repair volumes, particularly in stage II lesions, than older counterparts. Additionally, bone repair volume increased with the number of implanted MSCs up to 1,000,000, beyond which no additional benefits were observed. No significant difference was observed in repair outcomes between different sources of MSCs (BMAC, allogenic, or expanded cells). The study also highlighted that a 'washing effect' was beneficial, particularly for larger-volume osteonecrosis when combined with core decompression. Partial bone repair was the more frequent event observed, while total bone repair of osteonecrosis was rare. The volume and stage of osteonecrosis, alongside the number of injected cells, significantly affected treatment outcomes. In summary, this study provides comprehensive insights into the effectiveness and variables influencing the use of mesenchymal stem cells in treating human hip osteonecrosis. It emphasizes the potential of cell therapy while acknowledging the complexity and variability of results based on factors such as age, cell count, and disease stage.

Detection of SARS-CoV-2 in Cancellous Bone of Patients with COVID-19 Disease Undergoing Orthopedic Surgery: Laboratory Findings and Clinical Applications

An emerging issue for orthopedic surgeons is how to manage patients with active or previous COVID-19 disease, avoiding any major risks for the surgeons and the O.R. personnel. This monocentric prospective observational study aims to assess the prevalence of SARS-CoV-2 viral RT-PCR RNA in cancellous bone samples in patients with active or previous COVID-19 disease. We collected data about 30 consecutive patients from our institution from January 2021 to March 2021 with active or previous COVID-19 disease. The presence of SARS-CoV-2 in the samples was determined using two different PCR-based assays. Eighteen of the thirty patients included in the study had a positive nasopharyngeal swab at the time of surgery. Twelve patients had a negative nasopharyngeal swab with a mean days since negativization of 138 ± 104 days, ranging from 23 to 331 days. Mean days of positivity to the nasal swab were 17 ± 17. Twenty-nine out of thirty (96.7%) samples were negative for the presence of SARS-CoV-2 RNA. In one sample, low SARS-CoV-2 load (Cycle threshold (Ct) 36.6.) was detected but not confirmed using an additional confirmatory assay. The conducted study demonstrates the absence of the viral genome within the analyzed cancellous bone. We think that the use of personal protection equipment (PPE) to only protect from aerosol produced during surgery, both in active and recovered patients, is not strictly necessary. We think that the use of PPE should not be employed by surgeons and the O.R. personnel to protect themselves from aerosols produced from the respiratory tract. Moreover, we think that our results could represent a valid basis for further studies related to the possibility of bone donation in patients that suffered and recovered from COVID-19.

Subchondral and intra-articular injections of bone marrow concentrate are a safe and effective treatment for knee osteoarthritis: a prospective, multi-center pilot study

PURPOSE

Subchondral bone is becoming a treatment target for knee OA patients, with promising early findings on the use of bone marrow aspirate concentrate (BMAC). The aim of this prospective, multi-centric pilot study was to evaluate safety as well as clinical and MRI outcomes of a combined approach of intra-articular and subchondral BMAC injections.

METHODS

Thirty patients (19 men, 11 women, 56.4 ± 8.1 years) with symptomatic knee OA were treated with a combination of an intra-articular and two subchondral BMAC injections (femoral condyle and tibial plateau). Patients were evaluated at baseline and at 1-3-6-12 months of follow-up with the IKDC subjective, VAS, KOOS, and EQ-VAS scores. The MRI evaluation was performed with the WORMS score.

RESULTS

No major complications were reported and only two patients were considered treatment failures, requiring a new injective or surgical treatment. The IKDC subjective score improved significantly from 40.5 ± 12.5 to 59.9 ± 16.1 at 3 months, 59.1 ± 12.2 at 6 months, and 62.6 ± 19.4 at 12 months (p < 0.0005). A similar improvement was reported for VAS pain and all KOOS subscales at all follow-ups, while EQ-VAS did not show any significant improvement. The MRI analysis showed a significant bone marrow edema reduction (p = 0.003), while the remaining WORMS parameters did not show any significant changes.

CONCLUSION

The pilot evaluation of this combined BMAC injective treatment showed safety and positive outcome up to 12 months of follow-up in patients with symptomatic knee OA associated with subchondral bone alterations. These findings suggest that targeting both subchondral bone and joint environment can provide promising results, and that BMAC can be a valid option for this combined approach to treat knee OA.

Decreased volume of hip fractures observed during COVID-19 lockdown

INTRODUCTION

The aim was to study the incidence and characteristics of fragility hip fractures admitted during COVID-19 lockdown.

MATERIALS AND METHODS

We analysed socio-demographic and baseline characteristics of patients suffering fragility hip fractures between March 1st and May 1st 2020, period most affected by COVID-19 confinement measures. Cases (n = 64) were compared with controls (n = 172) from corresponding periods in 2018 and 2019. Poisson Generalised Linear Model regression analysis was performed to compare daily case counts, and LOESS curves compared time series.

RESULTS

No differences were found regarding age or gender distributions, pre-fracture living, ambulatory, functional or cognitive status. More patients in 2020 had a high-risk ASA score. Fewer cases [Reduction = 26% (95% CI 1-44%)] were admitted in 2020. The reduction seemed to correspond with confinement.

CONCLUSIONS

Approximately, one quarter less fragility hip fractures were admitted to our hospital during lockdown. Patients' baseline status and socio-demographic characteristics were similar.

Ankle osteonecrosis in fifty-one children and adolescent's leukemia survivors: a prospective randomized study on percutaneous mesenchymal stem cells treatment

PURPOSE

Corticoid treatment associated with haematologic treatments can lead to ankle osteonecrosis in children's survivors of acute leukemia (ALL). Based on the efficiency of mesenchymal stem cells (MSCs) in hip osteonecrosis, we performed an evaluation of this treatment in 51 children and adolescents who had symptomatic ankle osteonecrosis after therapy for haematologic cancer.

MATERIAL AND METHODS

The 51 patients had a total of 79 osteonecrosis sites on MRI, with 29 talus sites, 18 metaphyseal tibia sites, 12 epiphyseal tibia sites, eight calcaneus sites, six fibula sites, four navicular sites, and two cuboid sites. In this prospective randomized trial, 37 ankles were addressed for cell therapy, 37 others for core decompression alone, and 20 were considered as a control group without treatment. We analyzed the outcome of this treatment osteonecrosis, the number and characteristics of bone marrow mesenchymal cells (MSCs) that could be transplanted, and the risks of tumorigenesis in these patients with haematologic cancers. The patients were operated on over a period of ten years from 2000 to 2010 and were monitored through December 31, 2019.

RESULTS

Despite a normal systemic blood cells count, MSCs in the iliac crest (counted as CFU-F) were in low number (1021 MSCs/mL; range 314-3015) and were of host origin after even allogeneic bone marrow transplantation. Better clinical outcomes (pain, foot and ankle deformity) and osteonecrosis repair on MRI with absence of collapse were obtained in ankles that received cell therapy as compared with those with core decompression alone or those without initial surgery. No tumour was found on MRI at the sites of injection and this study found no increased risk of recurrence or of new cancer in this population after an average follow-up of 15 years.

CONCLUSIONS

These results suggest that autologous MSCs can improve the quality of life of leukemia survivors with ankle osteonecrosis.

Cemented stems in healthy elderly patients result in higher hypoxia despite a paradoxical lower femoral increase of intramedullary pressure

PURPOSE

Hypoxia is a well-known complication in cemented arthroplasty; however, it is not known whether the level of hypoxia is related to the intramedullary pressure or to the age of the patient; therefore, we studied the intramedullary pressure and level of hypoxia in patients undergoing cemented arthroplasty.

METHODS

A prospective study was performed during cemented arthroplasties in 25 patients with an average age of 66.2 ± 12.1 years old. The intramedullary pressure (IMP) was measured by placing a pressure transducer within the bone while simultaneously measuring the pulse oximetry arterial oxygen saturation (SpO2), pulse, and blood pressure. These variables were obtained immediately after spinal anaesthesia, five minutes after cementation, and 15 minutes after prosthesis insertion.

RESULTS

One hundred percent of patients had hypoxia at some level, but 83% of elderly patients (older than 66.5 years) had hypoxia (SpO2 <94%) as compared to only 23% of younger patients (p = 0.006). In the group of young patients, IMP was roughly increased 32 times as compared with baseline level, with as consequences a decrease of 4% of SpO2 (from 98.3 to 94.15%); in the elderly group, the IMP was only increased 20 times, but a decrease of 6% of SpO2 (from 97.25 to 91%) was observed.

CONCLUSIONS

This series demonstrated higher hypoxia in elderly healthy patients despite a paradoxical lower femoral increase of intramedullary pressure as compared with younger patients. This hypoxia is probably not only related to the cement but also to the patient's age with decline of maximum oxygen uptake capacity and increase bone porosity.

CLINICAL TRIALS

ClinicalTrials.gov Identifier: NCT03930537 https://clinicaltrials.gov/ct2/show/NCT03930537.