Collection and reconstruction after harvesting donor tissues from the musculoskeletal system: Technique specific to the lower limbs

No Detectable Alteration of Inorganic Allogeneic Bone Matrix Colonizing Mesenchymal Cells: A Step Towards Personalized Bone Grafts

Background

During major bone substance loss, secured allogeneic bone matrix (ABM) is normally utilized for bone repair. Here, we propose a method to colonize ABM using autologous mesenchymal cells (MCs) to improve their integration. Moreover, in this study, the consequences of in vitro colonization on MCs have been evaluated.

Methods

After in vitro propagation of MCs, their proliferation kinetics on ABM pre-coated with gelatin, fibronectin, collagen IV and human serum (HS) was monitored, and they were compared with cells cultured without ABM for 8 weeks. The effect of ABM on cell phenotype was also assessed. Lastly, the ability of ABM-colonizing MCs to perform hematopoiesis, a function normally preserved in selected culture conditions, and their differentiation towards osteoblastic lineage were evaluated.

Results

MC and colony-forming unit-fibroblast proliferated 930- and 590-fold, respectively. The proliferation rate of the expanded MCs was higher, forming a 3-dimensional structure in all ABMs. Pre-coating with HS was the most efficient treatment of ABMs to increase the initial adherence of MCs, and it partly explains the reason for the higher propagation of MCs. Flow cytometry analyses revealed subtle alterations in ABM-colonizing cells; however, the ability of MCs to maintain long-term culture initiating cells proliferation and differentiate into osteoblastic lineage was preserved.

Conclusions

In this study, the in vitro biocompatibility of bone marrow (BM) MCs with ABMs, the role of HS in scaffold coating, and the possibility of initially using a small BM sample for this approach were demonstrated.

Use of morselized allografts for acetabular reconstruction during THA revision: French multicenter study of 508 cases with 8 years' average follow-up

BACKGROUND

In the context of acetabular reconstruction, bone defects can be filled with processed or unprocessed bone allografts. Published data are often contradictory on this topic and few studies have been done comparing processed allografts to fresh-frozen ones. This led us to conduct a large study to measure the factors impacting the survival of THA revision: (1) type of allograft and cup, (2) technical factors or patient-related factors.

HYPOTHESIS

Acetabular reconstruction can be performed equally well with frozen or processed morselized allografts.

MATERIALS AND METHODS

This retrospective, multicenter study of acetabular reconstruction included 508 cases with a minimum follow-up of 5 years. The follow-up for the frozen grafts was shorter (7.86 years±1.89 [5-12.32]) than that of the processed grafts (8.22 years±1.77 [5.05-15.48]) (p=0.029). However, the patients were younger at the time of the primary THA procedure in the frozen allograft group (51.5 years±14.2 [17-80]) than in the processed group (57.5 years±13.0 [12-94]) (p<0.001) and were also younger at the time of THA revision (67.8 years±12.2 [36.9-89.3] versus 70 years±11.7 [25-94.5]) (p=0.041).

RESULTS

There were more complications overall in the frozen allograft group (46/242=19.0%) than the processed allograft group (35/256=13.2%) (p=0.044) with more instances of loosening in the frozen group (20/242 [8.2%]) than in the processed group (6/266 [3.3%])(p=0.001). Conversely, the dislocation rate (16/242=6.6% vs. 17/266=6.4%) (p=0.844) and infection rate (18/242=7.4% vs. 15/266=5.7%) (p=0.264) did not differ between groups. The subgroup analysis reveal a correlation between the occurrence of a complication and higher body mass index (BMI) (p=0.037) with a higher overall risk of complications in patients with a BMI above 30 or under 20 (p=0.006) and a relative risk of 1.95 (95% CI: 1.26-2.93). Being overweight was associated with a higher risk of dislocation (relative risk of 2.46; 95% CI: 1.23-4.70) (p=0.007). Loosening was more likely to occur in younger patients at the time of the procedure (relative risk of 2.77; 95% CI: 1.52-6.51) (p=0.040) before 60 years during the revision. Lastly, patients who were less active preoperatively based on the Devane scale had an increased risk of dislocation (relative risk of 2.51; 95% CI: 1.26-8.26) (p=0.022).

DISCUSSION

Our hypothesis was not confirmed. The groups were not comparable initially, which may explain the differences found since the larger number of loosening cases in the frozen allograft group can be attributed to group heterogeneity. Nevertheless, morselized allografts appear to be suitable for acetabular bone defect reconstruction. A randomized study would be needed to determine whether frozen or processed allografts are superior.

LEVEL OF EVIDENCE

III, comparative retrospective study.

Update on the supply and use of allografts in locomotor system pathologies in France

Allografts are increasingly used in orthopedics. The main aim of the present study was to map the use of locomotor system allografts in France between 2012 and 2016. The study hypothesis was that there are great differences in the distribution and activity of tissue banks and graft preservation procedure quality, failing to meet national requirements.

MATERIAL AND METHODS

Data from activity reports of the French Biomedicine Agency (ABM) were collected for the period 2012-2016. Existing viral inactivation procedures were described. Preliminary results from a study of allograft requirements by the French Society of Arthroscopy (SFA) were reported.

RESULTS

Nineteen tissue banks were located. Four dealt exclusively with cryopreserved tissue, 3 exclusively with virus-inactivated bone, and 12 with both. Distribution analysis found wide disparities in geographic location and in type of activity. Viral inactivation is presently implemented only for femoral heads derived from hip replacement. Stocks of long bones, femoral heads and ligaments/tendons increased constantly over the study period, by 8.3%, 50.8% and 316.2% respectively. The SFA questionnaire confirmed a serious shortage of tissues, necessitating importation of allografts.

DISCUSSION

Each tissue bank had its own specificities and specialization. They should probably be coalesced, so as to centralize both supply and demand and improve nationwide response to requirements. Locomotor system tissue harvesting also needs to be expanded to meet increasing demand.