Aim of this study is the investigation of lower limbs biomechanics before and after meniscectomy.

Materials and methods: Ten volunteers candidate to partial medial meniscectomy underwent motion analysis before surgery, six months and one year after. Ten healthy volunteers acted as a control group

Data were acquired by means of Vicon motion analysis system

Results: In gait patterns investigation, joint kinematics does not show significant modifications before and 6 months after surgery, 12 months after surgery hip and knee show a greater flexion.

The dynamic analysis stresses alterations in knee sagittal moment. Before surgery the knee flexion moment is reduced. After partial meniscectomy the knee flexion moment increases in both the limbs. In squatting investigation, main focus was on repeatability. Before surgery high inter subjects variability affects knee joint angle; while after surgery high variability affects also hip and ankle.

Conclusions: After meniscectomy, gait and squatting patterns are still altered. Before surgery, the joint mechanical structure is not highly altered and modifications are mainly due to pain avoidance schemas; after partial meniscectomy, pain disappears and the new joint behaviours are probably caused by the new mechanical asset and/or proprioceptive mechanisms.

Biomaterial porosity is considered one of most important proprieties required to obtain fixation of bone ingrowth and ongrowth in prostheses.

Since 1998 in the USA and from in Europe a new highly porous biomaterial, Trabecular Metal Technology (TMT, ©Zimmer, USA) has been used in orthopaedic surgery.

This study evaluates the short-term morphological findings of porous tantalum screws implanted in three patients with osteonecrosis of a femoral head. Tantalum trabecular metal offers several advantages over conventional materials. Its regular porosity is considered one of most important properties in bone ingrowth and ongrowth and high biocompatibility and osteoconductivity. The biomechanical properties of tantalum are sufficient to withstand physiological load.

Our study disclosed a good integration. The bone penetrated the porous metal completely and many characteristics of good bio-integration were evident such as new formation of lamellae, presence of calcium and phosphorus elements, absence of fracture and signs of implant metallosis. The presence of peri-implant medullary cisternae confirmed the functional sites of new bone formation.

We conclude that the porous tantalum material is an optimal osteoinductor and osteoconductor even in critical conditions.

Collagen meniscus implant (CMI) is a tissue engineering technique for the management of irreparable meniscal lesions. In this study we evaluate morphological and biochemical changes occurring in CMI after implantation. Gene expression technique was also adopted to characterise the phenotype of the invading cells.

Light microscopy, immunohistochemistry (type I and II collagen), SEM and TEM analysis were performed on five biopsy specimens harvested from five different patients (range, 6 to 16 months after surgery). Fluorophore-assisted carbohydrate electrophoresis (FACE) and real-time PCR evaluation were carried out on two biopsy specimens harvested 6 and 16 months, respectively, after implantation. All these investigations were also applied on non-implanted scaffolds for comparison.

Scaffold sections appeared to be composed of parallel connective laminae, connected by smaller connective bundles surrounding elongated lacunae. In the biopsy specimens, the lacunae were filled by connective tissue with newly formed vessels and fibroblast-like cells. Immunohistochemistry revealed exclusively type I collagen in the scaffold, while type II collagen appeared in the biopsy specimens. FACE analysis carried out in the scaffold did not detect any GAG disaccharides. Conversely, disaccharides were detected in the implants. Real-time PCR showed a signal only for collagen type I. In the scaffolds no gene expression was recorded.

The morphological findings demonstrate that CMI is a biocompatible scaffold available for colonisation by connective cells and vessels. Biochemical data show a specific production of extracellular matrix after implantation. The absence of signal for type II collagen gene can be attributed to different maturation stages of the in-growing tissue.

Aim: Collagen meniscus implant (CMI) is a tissue engineering technique for the management of irreparable meniscal lesions. In this study we evaluate morphological and biochemical changes occurring in CMI after implantation, in order to better define tissue ingrowth inside the scaffold. Gene expression technique was also adopted to characterize the phenotype of the invading cells. Methods and materials: Morphological analysis was performed by light microscopy, immunohistochemistry (type I and II collagen), SEM and TEM on 5 biopsy specimens, harvested from 5 different patients (range, 6 to 16 months after surgery). Biochemical evaluation was carried out using Flurophore Assisted Carbohydrate Electrophoresis (FACE): this assay allowed to measure glycosaminoglycans (GAG) production in extracellular matrix of 2 biopsy specimens, harvested respectively 6 and 16 months after implantation. Real Time PCR was performed on the same 2 biopsy samples for detecting tissue-specific gene expression (collagen); RNAaseP gene expression was used as housekeeping gene. All these investigations were also applied on non implanted scaffolds for comparison.

Results: Scaffold sections appeared composed by parallel connective laminae of 10-30B5m, connected by smaller (5-10B5m) connective bundles, surrounding elongated lacunae of 40-60B5m in diameter. In the biopsies specimens, the lacunae were filled by connective tissue with newly formed vessels and fibroblast-like cells. In the extracellular matrix, the collagen fibrils showed uniform diameters. The original structure of CMI was still recognizable and no inflammatory cells were detected inside the implant. A more organized architecture of the fibrillar network was evident in specimens with longer follow-up. Immunohistochemistry revealed exclusively type I collagen in the scaffold, while type II collagen appeared and was predominant in the biopsies specimens. FACE analysis carried out in the scaffold did not detect any GAG disaccharides. Conversely, high amount of disaccharides (unsulphated chondroitin, 4 and 6 sulphated chondroitin) were detected, together with hyaluronan, in the implants. Real Time PCR showed signal for Collagen type I alpha 1 and no signal for Collagen type II alpha 1. In the scaffolds used for comparison, no gene expression was recorded.

Conclusions: The morphological findings of this study demonstrate that CMI acts as a biocompatible scaffold which provide a three-dimensional structure available for colonization by connective cells and vessels. Biochemical data are consistent with an active and specific production of extracellular matrix in the scaffold after implantation. The absence of signal for type II collagen gene in biopsies specimens can be attributed to different maturation stages of the ingrowing tissue.