PRP is widely used in the clinical management of chronic tendinopathy. However, the clinical results are ambiguous. It is imperative to understand the influence of leukocytes on PRP-mediated tissue healing in vivo, which could facilitate the better clinical management of chronic tendinopathy. Further studies are needed to translate our findings to the clinical setting.

Nestin defines a novel tendon stem/progenitor cell subpopulation with high tenogenesis potential.

a b s t r a c tRotator cuff tear is one of the most common types of shoulder injuries, often resulting in pain and physical debilitation. Allogeneic tendon-derived decellularized matrices do not have appropriate pore size and porosity to facilitate cell infiltration, while commercially-available synthetic scaffolds are often inadequate at inducing tenogenic differentiation. The aim of this study is to develop an advanced 3D aligned collagen/silk scaffold (ACS) and investigate its efficacy in a rabbit massive rotator cuff tear model. ACS has similar 3D alignment of collagen fibers as natural tendon with superior mechanical characteristics. Based on ectopic transplantation studies, the optimal collagen concentration (10 mg/ml), pore diameter (108.43 ± 7.25 lm) and porosity (97.94 ± 0.08%) required for sustaining a stable macro-structure conducive for cellular infiltration was determined. Within in vitro culture, tendon stem/progenitor cells (TSPCs) displayed spindle-shaped morphology, and were well-aligned on ACS as early as 24 h. TSPCs formed intercellular contacts and deposited extracellular matrix after 7 days. With the in vivo rotator cuff repair model, the regenerative tendon of the ACS group displayed more conspicuous native microstructures with larger diameter collagen fibrils (48.72 ± 3.75 vs. 44.26 ± 5.03 nm) that had better alignment and mechanical properties (139.85 ± 49.36 vs. 99.09 ± 33.98 N) at 12 weeks post-implantation. In conclusion, these findings demonstrate the positive efficacy of the macroporous 3D aligned scaffold in facilitating rotator cuff tendon regeneration, and its practical applications for rotator cuff tendon tissue engineering. Statement of SignificanceMassive rotator cuff tear is one of the most common shoulder injuries, and poses a formidable clinical challenge to the orthopedic surgeon. Tissue engineering of tendon can potentially overcome the problem. However, more efficacious scaffolds with good biocompatibility, appropriate pore size, favorable inductivity and sufficient mechanical strength for repairing massive rotator cuff tendon injuries need to be developed. In this study, we developed a novel macroporous 3D aligned collagen/silk scaffold, and demonstrated that this novel scaffold enhanced the efficacy of rotator cuff tendon regeneration by inducing aligned supracellular structures similar to natural tendon, which in turn enhanced http://dx

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BackgroundLumbar disc removal is currently the standard treatment for lumbar disc herniation. No consensus has been achieved whether aggressive disc resection with curettage (discectomy) versus conservative removal of the offending disc fragment alone (sequestrectomy) provides better outcomes. This study aims to compare the reherniation rate and clinical outcomes between discectomy and sequestrectomy by literature review and a meta-analysis.MethodsA systematic search of PubMed, Medline, Embase and the Cochrane Library was performed up to June 1, 2014. Outcomes of interest assessing the two techniques included demographic and clinical baseline characteristics, perioperative variables, complications, recurrent herniation rate and post-operative functional outcomes.ResultsTwelve eligible trials evaluating discectomy vs sequestrectomy were identified including one randomized controlled study, five prospective and six retrospective comparative studies. By contrast to discectomy, sequestrectomy was associated with significantly less operative time (p<0.001), lower visual analogue scale (VAS) for low back pain (p<0.05), less post-operative analgesic usage (p<0.05) and better patients’ satisfaction (p<0.05). Recurrent herniation rate, reoperation rate, intraoperative blood loss, hospitalization duration and VAS for sciatica were without significant difference.ConclusionsAccording to our pooled data, sequestrectomy entails equivalent reherniation rate and complications compared with discectomy but maintains a lower incidence of recurrent low back pain and higher satisfactory rate. High-quality prospective randomized controlled trials are needed to firmly assess these two procedures.

BackgroundThe study aimed to develop a novel orthopedic surgical scaffold made of collagen and silk to repair the tendon and bone interface, and to investigate its influence on tendon and bone healing in a rabbit model.Material/MethodsFour types of surgical scaffold were prepared, including a random collagen scaffold (RCS), an aligned collagen scaffold (ACS), a random collagen scaffold combined with knitted silk (RCSS), and an aligned collagen scaffold combined with knitted silk (ACSS). Rabbit bone marrow stem cells (BMSCs) were cultured and seeded onto the RCS and ACS scaffold. The animal model included four-month-old female New Zealand White rabbits (N=20) that underwent drilling into the rotator cuff of the left supraspinatus muscle tendon, randomized into the ACSS and RCSS groups.ResultsRabbit BMSCs adhered to and proliferated on the RCS and ACS in vitro. Transcription levels of the COL I, COL III, and tenascin (TCN) genes were significantly increased in the ACS group compared with the RCS group. Transcription levels of COL I, runt-related transcription factor-2 (RUNX-2) and bone morphogenetic protein-2 (BMP-2) were significantly increased in the RCS group compared with the ACS group. RCSS and ACSS implanted in the rabbit models for eight weeks resulted in more regenerative tissue in the RCSS group compared with the ACSS group, with new cartilage at the tendon and bone interface at 12 weeks.ConclusionsA collagen and silk scaffold improved healing of the tendon and bone interface in a rabbit model.