A Biomechanical and Ease of Learning Comparison Study of Arthroscopic Sliding Knots.

INTRODUCTION: This study aims to compare the biomechanical properties and ease of learning and tying of our novel knot (UM Knot) with other commonly used arthroscopic sliding knots. MATERIALS AND METHODS: The Duncan, HU, SMC, Pretzel, Nicky's and square knots were selected for comparisons with UM knot. All knots were prepared with size 2 HiFi® suture by a single experienced surgeon and tested with cyclic loading and load to failure tests. The ease of learning was assessed objectively by recording the time to learn the first correct knot and the total number of knots completed in 5 min by surgeons and trainees. RESULTS: The UM knot average failure load is significantly superior to the HU knot (p < 0.05) and comparable to Duncan, SMC, Pretzel and Nicky's knots. According to the ease of learning assessment, UM, Duncan, SMC, Pretzel and Nicky's knots took statistically less time to learn than the HU knot. Although not significant, the failure count due to slippage is fewer in UM knot compared with other knots. CONCLUSIONS: This study showed that UM knot is among the easiest knot to learn and tie, along with Duncan, SMC, Pretzel and Nicky's knots. Their biomechanical properties are comparable and their loads to failure were superior to the HU knot.

Low-Cost Self-Made Arthroscopic Training Camera Is Equally as Effective as Commercial Camera: A Comparison Study.

PURPOSE: To assess the effectiveness of a low-cost self-made arthroscopic camera (LAC) in basic arthroscopic skills training compared with a commercial arthroscopic camera (CAC). METHODS: One hundred fifty-three orthopaedic residents were recruited and randomly assigned to either the LAC or CAC. They were allocated 2 practice sessions, with 20 minutes each, to practice 4 given arthroscopic tasks: task 1, transferring objects; task 2, stacking objects; task 3, probing numbers; and task 4, stretching rubber bands. The time taken for participants to complete the given tasks was recorded in 3 separate tests; before practice, immediately after practice, and after a period of 3 months. A comparison of the time taken between both groups to complete the given tasks in each test was measured as the primary outcome. RESULTS: Significant improvements in time completion were seen in the post-practice test for both groups in all given arthroscopic tasks, each with P < .001. However, there was no significant difference between the groups for task 1 (P = .743), task 2 (P = .940), task 3 (P = .932), task 4 (P = .929), and total (P = .944). The outcomes of the tests (before practice, after practice, and at 3 months) according to repeated measures analysis of variance did not differ significantly between the groups in task 1 (P = .475), task 2 (P = .558), task 3 (P = .850), task 4 (P = .965), and total (P = .865). CONCLUSIONS: The LAC is equally as effective as the CAC in basic arthroscopic skills training with the advantage of being cost-effective. CLINICAL RELEVANCE: In view of the scarcity in commercial arthroscopic devices for trainees, this low-cost device, which trainees can personally own and use, may provide a less expensive and easily available way for trainees to improve their arthroscopic skills. This might also cultivate more interest in arthroscopic surgery among junior surgeons.

Correlation between Focal Nodular Low Signal Changes in Hoffa's Fat Pad Adjacent to Anterior Femoral Cartilage and Focal Cartilage Defect Underlying This Region and Its Possible Implication.

Purpose. This study investigates the association between focal nodular mass with low signal in Hoffa's fat pad adjacent to anterior femoral cartilage of the knee (FNMHF) and focal cartilage abnormality in this region. Method. The magnetic resonance fast imaging employing steady-state acquisition sequence (MR FIESTA) sagittal and axial images of the B1 and C1 region (described later) of 148 patients were independently evaluated by two reviewers and categorized into four categories: normal, FNMHF with underlying focal cartilage abnormality, FNMHF with normal cartilage, and cartilage abnormality with no FNMHF. Results. There was a significant association (p = 0.00) between FNMHF and immediate adjacent focal cartilage abnormality with high interobserver agreement. The absence of focal nodular lesions next to the anterior femoral cartilage has a very high negative predictive value for chondral injury (97.8%). Synovial biopsy of focal nodular lesion done during arthroscopy revealed some fibrocollagenous tissue and no inflammatory cells. Conclusion. We postulate that the FNMHF adjacent to the cartilage defects is a form of normal healing response to the cartilage damage. One patient with FHMHF and underlying cartilage abnormality was rescanned six months later. In this patient, the FNMHF disappeared and normal cartilage was observed in the adjacent region which may support this theory.

Identification of Pathways Mediating Growth Differentiation Factor5-Induced Tenogenic Differentiation in Human Bone Marrow Stromal Cells.

To date, the molecular signalling mechanisms which regulate growth factors-induced MSCs tenogenic differentiation remain largely unknown. Therefore, a study to determine the global gene expression profile of tenogenic differentiation in human bone marrow stromal cells (hMSCs) using growth differentiation factor 5 (GDF5) was conducted. Microarray analyses were conducted on hMSCs cultures supplemented with 100 ng/ml of GDF5 and compared to undifferentiated hMSCs and adult tenocytes. Results of QuantiGene® Plex assay support the use and interpretation of the inferred gene expression profiles and pathways information. From the 27,216 genes assessed, 873 genes (3.21% of the overall human transcriptome) were significantly altered during the tenogenic differentiation process (corrected p<0.05). The genes identified as potentially associated with tenogenic differentiation were ARHGAP29, CCL2, integrin alpha 8 and neurofilament medium polypeptides. These genes, were mainly associated with cytoskeleton reorganization (stress fibers formation) signaling. Pathway analysis demonstrated the potential molecular pathways involved in tenogenic differentiation were: cytoskeleton reorganization related i.e. keratin filament signaling and activin A signaling; cell adhesion related i.e. chemokine and adhesion signaling; and extracellular matrix related i.e. arachidonic acid production signaling. Further investigation using atomic force microscopy and confocal laser scanning microscopy demonstrated apparent cytoskeleton reorganization in GDF5-induced hMSCs suggesting that cytoskeleton reorganization signaling is an important event involved in tenogenic differentiation. Besides, a reduced nucleostemin expression observed suggested a lower cell proliferation rate in hMSCs undergoing tenogenic differentiation. Understanding and elucidating the tenogenic differentiation signalling pathways are important for future optimization of tenogenic hMSCs for functional tendon cell-based therapy and tissue engineering.

Effect of growth differentiation factor 5 on the proliferation and tenogenic differentiation potential of human mesenchymal stem cells in vitro.

The use of growth differentiation factor 5 (GDF-5) in damaged tendons has been shown to improve tendon repair. It has been hypothesized that further improvements may be achieved when GDF-5 is used to promote cell proliferation and induce tenogenic differentiation in human bone marrow-derived mesenchymal stem cells (hMSCs). However, the optimal conditions required to produce these effects on hMSCs have not been demonstrated in previous studies. A study to determine cell proliferation and tenogenic differentiation in hMSCs exposed to different concentrations of GDF-5 (0, 5, 25, 50, 100 and 500 ng/ml) was thus conducted. No significant changes were observed in the cell proliferation rate in hMSCs treated at different concentrations of GDF-5. GDF-5 appeared to induce tenogenic differentiation at 100 ng/ml, as reflected by (1) a significant increase in total collagen expression, similar to that of the primary native human tenocyte culture; (2) a significant upregulation in candidate tenogenic marker gene expression, i.e. scleraxis, tenascin-C and type-I collagen; (3) the ratio of type-I collagen to type-III collagen expression was elevated to levels similar to that of human tenocyte cultures, and (4) a significant downregulation of the non-tenogenic marker genes runt-related transcription factor 2 and sex determining region Y (SRY)-box 9 at day 7 of GDF-5 induction, further excluding hMSC differentiation into other lineages. In conclusion, GDF-5 does not alter the proliferation rates of hMSCs, but, instead, induces an optimal tenogenic differentiation response at 100 ng/ml.