Identification and distribution of synthetic ligament wear particles in sheep

Abstract

After one year, wear of medial collateral ligament replacements in sheep resulted in the presence of large numbers of wear particles and fibers in the joint space. This study examined the frequency of transport of these particles to the regional lymph nodes and to the liver and spleen. Inguinal, iliac, and paraaortic nodes were examined with regular and polarized light for the presence of particles presumably originating from polyethylene, aramid, polytetrafluoroethylene, polyesterterephthalate, polylacticacid, and carbon ligaments. Lymph nodes from sheep that had received tendon autograft replacements were also evaluated. Particles were observed in 33% of all nodes and in at least one node in 84% of all sheep. Particles were found in contralateral nodes, but not in the spleen or liver. Particles were observed usually as intracellular in foamy histiocytes, although extracellular carbon fibers and extracellular aramid fibers were also seen. Giant cells were occasionally detected in the polytetrafluoroethylene, polyethylene, and aramid nodes. In the polytetrafluoroethylene nodes and in the autograft nodes particles containing Mg, Si, and Fe were identified by elemental analysis. The morphological similarities between various birefringent particles and the particles indirectly identified as talc have led us to question the identification of wear debris solely on the basis of birefringence.

Tissue response to partially in vitro predegraded poly-L-lactide implants

“…In a clinical setting using poly L-DL lactide pins (70/30, Polypin s ) intra-articularly in sheep also an increase in time was observed for draining lymph node involvement [34], although the polarizing material could not be unequivocally attributed to the implants. The suggestion was made that talc could be involved as well [34,35]. In this respect crystalline remnants of degradable materials may resemble and thus behave similarly to wear particles as long as complete degradation and tissue restoration is not obtained.…”

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“…Only in a few cases are fibrous particles with a size of >5-10 µm identifiable in lymph nodes and are then probably transported outside cells by means of other mecha-nisms (material, type of wear, overburdened transport system) [2,5,6]. The larger particles were surrounded by multinucleated giant cells; smaller fragments were inside macrophages or eosinophile granulocytes.…”

“…The extent of this transport is discussed in connection with toxic effects in the form of inflammatory processes, dermatitis, eosinophilia, vasculitis, aseptic bone necrosis and formation of pseudotumors [1,2]. It is one of the main causes of failure of these implants and at the same time an unavoidable phenomenon when bearing surfaces come into contact.…”

“…Particles of different types in the liver and spleen of patients with hip prostheses could not be conclusively attributed to the implant [2,[3][4][5][6][7][8][9][10][11]. In studies on patients with total hip prostheses, evidence was found in the regional lymph nodes of the presence of particles which were birefringent under polarised light and metal, ceramic and carbon particles revealed by energy dispersive radiograph analysis (EDX).…”

Augmentation in anterior cruciate ligament reconstruction—a histological and biomechanical study on goats

“…During the incorporation and remodeling of the transplant, a mechanical weakening occurs [1,17,21], and to avoid this, synthetic ligaments are used as augmentation. The initial favorable short-term results were, however, followed by a high failure rate [7,12].…”