Infra-patellar fat pad-derived mesenchymal stem cells maintain their chondrogenic differentiation potential after arthroscopic harvest with blood-product supplementation.

PURPOSE: Mesenchymal stem cells/medicinal signaling cells (MSCs) possess therapeutic potential and are used in regenerative orthopaedics. The infra-patellar fat pad (IFP) is partially resected during knee arthroscopy (KASC) and contains MSCs. Heat, irrigation, and mechanical stress during KASC may decrease MSC's therapeutic potential. This study assessed MSCs' regenerative potential after arthroscopic IFP harvest and potential effects of two blood products (BP) (platelet-rich plasma (PRP), hyperacute serum (HAS)) on MSCs' viability and chondrogenic differentiation capacity. METHODS: IFP was arthroscopically harvested, isolated, and counted (n = 5). Flow cytometry was used to assess cell viability via staining with annexin V/7-AAD and stemness markers via staining for CD90, CD73, and CD105. MSCs were incubated with blood products, and metabolic activity was determined via an XTT assay. Deposition of cartilage extracellular matrix was determined in histologic sections of chondrogenically differentiated 3D pellet cultures via staining with Alcian Blue. Expression of cartilage-specific genes (SOX9, MMP3/13, ACAN, COL1/2) was analyzed via quantitative PCR. RESULTS: MSC isolation from IFP yielded 2.66*106 ± 1.49*106 viable cells from 2.7 (0.748) g of tissue. MSC markers (CD 90/105/73) were successfully detected and annexin V staining showed 81.5% viable cells. XTT showed increased metabolic activity. Within the BP groups, this increase was significant (days 0-14, p < 0.05). PCR showed expression of cartilage-specific genes in each group. COL2 (p < 0.01) as well as ACAN (p < 0.001) expression levels were significantly higher in the HAS group. Histology showed successful differentiation. CONCLUSION: Arthroscopic harvest of IFP-MSCs yields sufficient cells with maintained regenerative potential and viability. Blood products further enhance MSCs' viability.

Extensor Mechanism Reconstruction Using Allograft Following Total Knee Arthroplasty: A Review of Current Practice.

The disruption of the extensor mechanism/apparatus of the knee is a dreaded complication following Total Knee Arthroplasty (TKA). Fresh frozen allograft containing the patella, and peripatellar musculotendinous attachments has emerged as an ideal alternative or salvageable option for the efficient reconstruction of extensor mechanism disrupted following TKA, where repair is almost impossible. However, any allograft implantation is associated with certain complications and extensor apparatus allograft is not the exception. Despite being allogenic, reconstruction of the extensor mechanism of the knee using allograft has given promising results. This narrative review aims to elaborate on the current application of allograft in the reconstruction of the disrupted extensor mechanism following TKA.

The Effect of Blood-Derived Products on the Chondrogenic and Osteogenic Differentiation Potential of Adipose-Derived Mesenchymal Stem Cells Originated from Three Different Locations.

BACKGROUND: Adipose-derived mesenchymal stem cells (AD-MSCs) from fat tissue considered "surgical waste" during joint surgery may provide a potent source for regenerative medicine. Intra-articular, homologous fat tissue (Hoffa's fat pad, pouch fat) might possess a superior chondrogenic and osteogenic differentiation potential in comparison to extra-articular, nonhomologous fat. Blood products might further enhance this potential. METHODS: AD-MSCs were isolated from fat tissue of 3 donors from 3 locations each, during total knee replacement. Isolated cells were analyzed via flow cytometry. Cells were supplemented with blood products: two types of platelet-rich plasma (EPRP-PRP prepared in the presence of EDTA; CPRP-PRP prepared in the presence of citrate), hyperacute serum (hypACT), and standard fetal calf serum (FCS) as a positive control. The viability of the cells was determined by XTT assay, and the progress of differentiation was tested via histological staining and monitoring of specific gene expression. RESULTS: Blood products enhance ex vivo cell metabolism. Chondrogenesis is enhanced by EDTA-PRP and osteogenesis by citrate PRP, whereas hyperacute serum enhances both differentiations comparably. This finding was consistent in histological analysis as well as in gene expression. Lower blood product concentrations and shorter differentiation periods lead to superior histological results for chondrogenesis. Both PRP types had a different biological effect depending upon concentration, whereas hyperacute serum seemed to have a more consistent effect, independent of the used concentration. CONCLUSION: (i) Blood product preparation method, (ii) type of anticoagulant, (iii) differentiation time, and (iv) blood product concentration have a significant influence on stem cell viability and the differentiation potential, favouring no use of anticoagulation, shorter differentiation time, and lower blood product concentrations. Cell-free blood products like hyperacute serum may be considered as an alternative supplementation in regenerative medicine, especially for stem cell therapies.

Grade III Distal Medial Collateral Ligament Tear Missed by Magnetic Resonance Imaging: A Report of Two Cases.

Medial collateral ligament (MCL) injuries are the most common knee ligament injuries. Magnetic resonance imaging (MRI) is the investigation of choice for detecting such injuries. We report two cases of acute grade 3 MCL tears in young adults in which the injury was suspected clinically and was later confirmed by surgical exploration. However, the MRI failed to pick up the exact nature of injury. This report signifies the importance of an appropriate clinical examination for MCL injuries and stresses that decision-making for treatment should be based on the clinical examination rather than the MRI.

Proximal hamstring reconstruction using semitendinosus and gracilis autograft: a novel technique.

The complete proximal hamstring avulsion is relatively uncommon injury and predominantly occurs in young athletes but causes significant functional impairment. In chronic cases, the muscle mass is so much retracted that primary repair is not possible. A surgical technique for reconstruction of chronic proximal hamstring avulsion using contralateral semitendinosus and gracilis autograft is described in this case report. LEVEL OF EVIDENCE: V.

Effects of a femoral shaft fracture on multiply injured patients with a head injury.

To study the effects of a femoral shaft fracture and its early stabilization on the morbidity, mortality, and outcome of patients with multiple injuries and a concomitant head injury, we analyzed the clinical course of patients using a prospectively gathered database. A series of 42 patients with multiple injuries, including head injuries and femoral fractures, formed the study group. A series of 133 patients with multiple injuries and head injuries but without femoral fractures formed the control group. The parameters examined included injury severity, injury pattern, hemodynamics at admission, mortality, duration of ventilation, length of intensive care unit (ICU) stay, and outcome. There were no significant differences regarding the demographics, injury severity score (ISS), injury pattern except the extremity Abbreviated Injury Scale (AIS) between the study and control groups. No significant differences were found in terms of mortality, duration of ventilation/ICU stay, and outcome. Injury severity (ISS), severity of the head injury (AIS), and hemodynamics at admission were shown to have a significant effect on the examined parameters. The present study suggests that a femoral fracture and its early stabilization in a multitrauma patient with a concomitant head injury do not adversely affect mortality and outcome and supports aggressive surgical management for these patients.