Eitan Melamed

Rabin Medical Center, Tell Afif, Tel Aviv, Israel

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Publications (12)68.88 Total impact

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    ABSTRACT: INTRODUCTION: Many disorders in clinical orthopedics present tissue degeneration and lack of repair due to lack of a scaffold., Chitosan is a sugar polymer that is produced from chitin., The current abstract describes our experience with chitosan as a tissue regeneration supporting scaffold. MATERIALS AND METHODS:, Several models were evaluated including the rat acute rotator cuff model, the lapine Masuda's disc degeneration model and, the medial menisectomy rat model., RESULTS: The use of chitosan enhances tendon repair in the rat rotator cuff model and prevents muscle atrophy., The use of chitosan gel appears to prevent disc degeneration in the masuda model., In the osteoarthritis model the use of chitosan leads to better cartilage preservation and less osteophyte formation., Animal pain is reduced as measured using an in capacitance meter. DISCUSSION:, The use of chitosan gel allows repair of several difficult animal models simulating common orthopedic maladies.
  • Ilan Cohen, Eitan Melamed, Dror Robinson, Zvi Nevo
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    ABSTRACT: The potential of fresh whole chick epiphyses of embryonic origin to serve as implant material for cartilage defects of aged chicken was tested. Fresh epiphyses of 11-day-old embryos were collected from 24 animals and transplanted into defects created in the weight-bearing areas of tibiotarsal joint cartilage of 2-year-old chicks. Upon sacrifice, samples were examined macroscopically and microsections were prepared for histology. Macroscopically, control defects remained empty at all the time intervals. Defects of the experimental group were, on the other hand, filled with cartilaginous tissue as early as 2 weeks posttransplantation, although individual epiphyses could still be noted in the implant tissue. At 4 weeks and later, defects were filled with cartilaginous material indistinguishable from hyaline cartilage. Histologically, all grafts remained within the defect's pits, showing mitotic and metabolic activity typical to proliferating hyaline cartilage. The engrafted epiphyses showed a partial incorporation and integration with the surrounding host tissues already at 2 weeks. At 4 weeks and later, the integration was complete. It is concluded that a chick embryonic epiphyseal cartilage is suitable as a graft source for articular cartilage transplantation. The embryonic epiphyses provide immediate inherent stability to the graft and supply a good mix of mesenchymal progenitor cells responsible for the high rate of cell proliferation and adhesion to the differentiated committed chondrocytes of the host that create the typical favorable chondrogenic milieu. Based on the present findings, it is postulated that human embryonic epiphyses may, in the future, represent an alternative source to the commonly used techniques of hyaline cartilage repair.
    Archives of Orthopaedic and Trauma Surgery 12/2007; 127(9):763-8. · 1.31 Impact Factor
  • The Journal of trauma 06/2007; 62(5):1281-3. · 2.96 Impact Factor
  • E Melamed, A Garti, D Robinson
    Injury 03/2007; 38(2):256. · 2.46 Impact Factor
  • Eitan Melamed, Dror Robinson
    The Journal of trauma 06/2006; 60(5):1150-1. · 2.96 Impact Factor
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    ABSTRACT: We report a case of chondroma of the heel causing chronic heel pain. At the initial examination, the case was misdiagnosed as proximal plantar fasciitis and was treated as such for 6 months prior to operative treatment. Soft tissue tumours in the foot can easily be overlooked and misdiagnosed as plantar fasciitis because of the rarity and similarity of symptoms to those of other frequently encountered foot disorders. In the present case surgical excision of the tumour resulted in immediate and complete relief of chronic heel pain. Awareness that persistent heel pain may be caused not only by plantar fasciitis is prudent for establishing a suitable differential diagnosis in these cases.
    The Foot 01/2006; 16(3):175-177.
  • Eitan Melamed, Ilan Cohen, Dror Robinson
    New England Journal of Medicine 02/2005; 352(1):95-7; author reply 95-7. · 54.42 Impact Factor
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    Ilan Cohen, Dror Robinson, Eitan Melamed, Zvi Nevo
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    ABSTRACT: A method for growth and maintenance of vital cartilaginous tissue is necessary for cartilage repair by in-vitro produced biologic implants. A previously tested perfusion system simulating joint activity was used. Whole epiphyses collected from thirty 11-day-old chick embryos were divided into two groups. One group was grown in a tissue culture dish for 10 days. The other group was placed in a perfusion system termed a joint-simulating device (JSD). After a period of 10 days, histology and immunohistochemistry were performed on five epiphyses from each group. Histologically, epiphyses grown in the device coalesced into a homogenous three-dimensional mass. The bridging tissue between individual epiphyses was highly cellular (PCNA staining positive) and was composed of mesenchymal stem cells as shown by expression of FGF receptor 3. No such tissue formed between epiphyses in the tissue culture dish and the epiphyseal cores were shown to be necrotic. The rest of the epiphyses were evaluated for radioactive sulfate incorporation into glycosaminoglycans (GAGs). A tenfold increase in sulfate incorporation occurred in epiphyses grown within the JSD as compared to the traditional culture method. In conclusion, embryonic epiphyses could be a suitable source for the ex-vivo growth of tissue-engineered cartilage constructs that might later be used as an in-vivo cartilage implant. The joint simulating device effectively maintains cartilage viability and bioactivity for as long as 10 days.
    The Iowa orthopaedic journal 02/2005; 25:102-7.
  • Eitan Melamed, Dror Robinson
    Clinical Orthopaedics and Related Research 01/2005; · 2.88 Impact Factor
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    ABSTRACT: A prospective, controlled cohort study was conducted to assess the anatomic transverse location and clinical presentation of L3-L4 disc herniation compared with lower lumbar levels. This study prospectively identified 37 patients diagnosed with L3-L4 disc herniation (study group) and 52 patients diagnosed with L4-L5 and L5-S1 herniation (control group). The following clinical data were collected: age, femoral stretch test, motor strength, sensation, and deep tendon reflexes. The anatomic transverse location of the disc fragments was assessed by computed tomography or magnetic resonance imaging and was classified as either central, posterolateral, foraminal, or far lateral. The patients in the study group were older than the patients in the control group, and neurologic deficit was more common. The transverse location was foraminal and extraforaminal in 59% of the study group compared with 27% of the control group. These differences were statistically significant. The incidence of foraminal and far lateral disc herniation is significantly higher at the L3-L4 level compared with lower lumbar levels. When examining an older patient complaining of thigh pain, special attention should be given to the quadriceps strength, patellar reflex, and femoral stretch test. The L3-L4 foraminal and extraforaminal area should be assessed carefully.
    Journal of Spinal Disorders & Techniques 01/2005; 17(6):467-9. · 1.89 Impact Factor
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    ABSTRACT: This study compared the articular cartilage repair potential of cultured chondrocytes transplantation with bone-cartilage paste-graft in the resurfacing of full-thickness defects without breaching of the subchondral bone plate in rabbit knees. A 5 x 5-mm articular cartilage defect was created in the patellar groove of the femur. Three months following creation, the defect was filled with cultured autologous chondrocytes (group 1) or bone-cartilage paste (group 2). A control group of untreated defects was followed for 1 year. The reparative tissue was analyzed macroscopically, histologically, and by immunohistochemistry 3-12 months post-transplantation. The surfaces of the reparative tissue in group 1 were smooth, and the defects were filled with reparative tissue that resembled hyaline cartilage. The composition of the repair tissue more closely resembled cartilage, as demonstrated by cartilage-specific stains. In contrast, the reparative tissue in group 2 was fibrous and exhibited markers of mesenchymal stem cells and bone formation. Transplantation of cultured chondrocytes into a full-thickness defect in the rabbit generates a biologic substitute tissue that resembles native articular cartilage with living cells capable of synthesizing the surrounding cartilage matrix. In contrast, analysis of the healing response to the paste-graft technique failed to show cartilage-like characteristics. This information may be clinically applicable to direct the use of these treatments in chondral injuries.
    The journal of knee surgery 02/2004; 17(1):6-12.
  • Eitan Melamed, Dror Robinson
    Clinical Orthopaedics and Related Research 01/2004; 429:348-349. · 2.88 Impact Factor