Polyethylene wear is the main factor leading to periprosthetic osteolysis, aseptic loosening and long-term failure of the implant in total hip arthroplasty (THA). The present study compares the clinical and radiographic outcomes of 88 patients who underwent primary THA with either conventional polyethylene or cross-linked polyethylene (XLPE) from the same manufacturer (Zimmer®, Warsaw, IN, USA). There were no significant differences between the two sub-populations in average age, gender, side affected and prosthetic stem and cup size. The average follow-up was 104 months, ranging from 55 to 131 months: to our knowledge this is the longest follow-up for this particular insert. Clinical and x-ray evaluation was obtained at 1, 3, 6 and 12 months and yearly thereafter. Our results showed that cross-linked polyethylene has a significantly greater wear reduction than that of standard polyethylene.

Femoral fracture non-unions are considered to be rare, and are usually treated successfully with exchange nailing. However, recalcitrant aseptic cases often require additional bone grafting. The efficacy of BMP-7 in the treatment of recalcitrant aseptic femoral non-unions was studied.

Since 2003 a multicenter registry (bmpusergroup.co.uk) was created collecting details of BMP7 application in general, between different university hospitals across Europe. Demographic data, intraoperative details, complications, clinical outcome parameters, radiological healing, VAS pain score, EuroQol-5D, and return-to-work were prospectively recorded. Radiological healing was defined as the presence of callous in two planes over 3 cortices. The minimum follow up was 12 months.

Seventeen patients, who had undergone a median of 1(1 to 4) prior revision operations, over a median period from the injury of 17 months(9 to 42), were included in this observational study. In 76.4%(13/17) the BMP7 was combined with revision of the fixation. Non-union healing was verified in 14/17 cases(82.3%) in a median period of 6.5 months(3–15). Over 80% of these patients returned to their pre-injury level of activities, the median overall health state score was 82.5(35 to 100). No adverse events or complications were associated with the BMP7 application over the median follow-up of 24 months(12–68).

Purpose: Femoral fracture non-unions are considered to be rare, and are usually treated successfully with exchange nailing. However, recalcitrant aseptic cases often require additional bone grafting procedures. The purpose of this study was to investigate the efficacy of BMP-7 (biological enhancement) in the treatment of recalcitrant aseptic femoral non-unions.

Material & Methods: Since 2003 a multicenter registry (bmpusergroup.co.uk) was created to collect details of BMP7 application in general, between different university hospitals across Europe. Demographic data, intraoperative details, complications, clinical outcome parameters, radiological healing, VAS pain score, EuroQol-5D, and return-to-work were prospectively recorded. Radiological healing was defined as the presence of callous in two planes over 3 cortices. The minimum follow up was 12 months.

Results: Thirty patients, who had undergone a median of 1 (1 to 5) prior revision operations, over a median period from the injury of 24 months (9 to 65), were included in this observational study. In 76.7% (23/30) the application of BMP7 was combined with a revision of the fixation. Non-union was verified in 26/30 cases (86.7%) in a median period of 6 months (range 4–10). Over 70% of these patients returned to their preinjury level of activities, the median overall health state score was 82.5 (45 to 95). No adverse events or complications were associated with the BMP7 application over the median follow-up of 30 months (12–68).

Discussion/Conclusion: This case series has verified the safety and efficacy of the use of BMP7 in a manner comparable to the scarce existing evidence on femoral non-unions. The establishment of multicenter networks and the systematic and long-term follow-up of these patients are expected to provide further information and significantly improve our understanding on this promising osteoinductive bone substitute.

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.

Introduction: In the two-stage revision procedure for infected total hip arthroplasty (THA), healing of the infection can be enhanced by using an antibiotic-loaded acrylic cement (ALAC) spacer. The spacer also acts as a temporary implant, preserving the gap between bone segments and a certain degree of joint motion.

Materials and methods: Between 1995 and 2003, 19 infected THAs were surgically treated by two-stage revision procedures, using gentamicin-loaded spacers. The infections were sustained by Staph. aureus in 7 cases, Staph. aureus + Enterococcus faecalis in 1 case, Staph. epidermidis in 4 cases, Strept, agalactiae in 1 case and Strept, β-haemoliticus in 1 case. In 5 hips presenting with secreting fistulae, no causative microrganisms were isolated.

Average interval between the two surgical stages was 5.5 months (range, 2 weeks to 13 months). Systemic antibiotics were administered to all patients for a minimum period of 6 weeks after removal of the infected implant. The revision stem was cemented in 5 patients and not cemented in 13 patients. All the acetabular components were uncemented. In one patient, the second stage procedure consisted exclusively in removal of the spacer and debridement, owing to persisting infection sustained by Staph. aureus + Staph. epidermidis.

Results: Seventeen patients were evaluated at an average follow up of 42.3 months (range, 6 to 92 months).

Recurrence of infection (Staph. aureus) occurred in 1 patient and was treated by resection-arthroplasty. Aseptic loosening of the stem was observed in 1 patient, who was subsequently treated by stem revision. Average Harris Hip Score was 78 points (range, 65 to 90 points).

Conclusions: The low incidence and the pathophysiologic heterogeneity of THA infections do not allow to identify standardised protocols for their treatment. Two-stage revision is one available option and several authors demonstrated higher rates of success when compared to one-stage revision. The use of ALAC spacers increases the efficacy of the procedure and in our experience positively influenced the clinical-functional outcome.

Non-union of the radius and/or ulna is comparatively common in the treatment of forearm fractures. Bone graft from the iliac crest secured by rigid plate fixation under compression is indicated in non-unions with a bone defect longer than 2 cm. The aim of the study is to compare the results with the current literature.

Thirteen patients (female: 1; males: 12), mean age 44 years (23–75 years), were treated in our department between 1993 and 2003. In 10 patients the original injury involved both radius and ulna; in the remaining three only the ulna was affected. All the fractures had been internally fixed, except for a radius fracture. Non-unions involved the ulna in eight cases, the radius in one case and both radius and ulna in four cases. A cortico-cancellous graft was used to fill a defect of the ulna in 11 cases and of the radius in two cases. In the non-unions of both bones only one bone was operated (one radius and three ulna); a different treatment was performed in the other bone. The mean time between the original injury and the indexed procedure was 7 months (3–14 months). The mean bone defect was 4 cm (2–6 cm). A T-shaped cortico-cancellous graft was always used. All the patients were evaluated clinically and radiographically with a mean follow-up of 4 years (1–10 years).

Bony union was achieved in all the patients at an average time of 4 months (3–6 months). At the follow-up the mean elbow flexion was 130°, the mean extension lag 4°, the mean pronation 71° and the mean supination 61°. The mean grip strength was 38 kg, 81% of the contralateral side.

Cortico-cancellous bone graft from the iliac crest is an effective technique to fill a bone defect of between 2 and 6 cm. Up to this length the mechanical properties of the graft are optimal for a rigid plate fixation under compression; moreover, biological conditions allow ready integration of the graft. Rigid fixation with cortico-cancellous bone graft from the iliac crest is a useful technique for forearm non-unions with a bone defect of between 2 and 6 cm.

Matrix-induced autologous chondrocyte implantation (MACI) is a tissue engineering technique which requires the use of a collagen membrane on which the cultured chondrocytes are seeded. We report on the arthroscopic MACI technique for the treatment of chondral defects in the lateral tibial plate of the knee.

The implantation procedure was performed on two male patients affected by traumatic chondral lesions, 2.5 and 2 cm² in size, respectively. The procedures were performed through traditional artrhoscopic portals and the seeded membrane was fixed with fibrin glue. Clinical-functional evaluation was performed according to ICRS score, modified Cincinnati knee score, IKDC, Lysholm II and Tegner scales. MRIs were taken 6, 12 and 24 months postoperatively.

After 2 years all the clinical scores were improved in both patients. MRI showed filling of the defects with hyaline-like tissue with reduction of subchondral bone oedema and restoration of a regular articular surface.

Even though the MACI technique is mostly performed with an open procedure, the site of these lesions could not be reached without sacrifying tendinous and ligamentous structures of the knee. With the arthroscopic approach an optimal view of the lesion could be achieved and appeared to be the best solution for these patients. The size of these defects was too large for bone marrow stimulation techniques and/or osteochondral grafts to be successful. By using fibrin glue for fixating the seeded membrane the procedure could be performed arthroscopically in a simple and safe way. No specifically designed instruments were used in these cases.

We prospectively evaluate clinical results and MRI findings on a series of 47 patients, with an average age of 31.7 years, treated by matrix-induced autologous chondrocyte implantation (MACI) for knee and ankle chondral defects.

As isolated lesions, the joints affected were 37 knees and five ankles. As combined lesions, there were four knees and one kissing lesion in the ankle. The average size of the defects was 3.5 cm². Clinical-functional evaluation was carried out according to ICRS, modified Cincinnati knee, Lysholm II and Tegner scales. The AOFAS score was used for the evaluation of the ankle. MRIs were taken before the operation as well as at 6, 12 and 24 months postoperatively. Among 10 second arthroscopic studies (four knees, six ankles), two biopsies were carried out after 2 years, from the medial femoral condyle and the patella, respectively. These specimens were evaluated by light microscopy, immunohistochemistry (type I and II collagen), SEM and TEM analysis.

Follow-up averaged 25.6 months. At the latest follow-up, knee scores improved after surgery. AOFAS did not improve in the patient with the kissing lesion. MRIs showed hyaline-like cartilage at the site of implantation in all treated joints with exception of the kissing lesion; four knees showed recurrence of subchondral bone oedema 1 year after surgery. Histological analysis on the biopsies revealed good definition of the tidemark and presence of type II collagen.

Clinical results and MRI findings support the efficacy of the MACI technique. Morphological findings are indicative for hyaline-like tissue formation in the implant site.

We report the clinical results and MRI findings observed in 50 patients who underwent collagen meniscus implant (CMI) between March 2001 and October 2003. Fifty patients affected by irreparable meniscal lesions or who had previously undergone partial medial meniscectomy were arthroscopically treated with CMI, a tissue engineering technique designed to promote meniscal regeneration. Average age at the time of surgery was 38.4 years. The average size of the lesion/defect was 4.3 cm. Additional procedures included 16 ACL reconstructions, eight high tibial osteotomies and two autologous chondrocyte implantations. All knees were evaluated according to the Lysholm II and Tegner activity scales. MRI was performed 6, 12 and 24 months postoperatively. Six arthroscopic examinations of the implant were performed at different times (6 to 16 months postoperatively).

Postoperative complications included saphenus neuroapraxia in three patients and CMI rupture in one patient who presented with persistent knee swelling. Follow-up averaged 16.5 months, with a minimum of 6 months. At the most recent evaluation, 46 patients showed an improvement in the clinical scores. A progressive, uniform signal was evident by MRI. At the second arthroscopic study, free fragments of the implant were observed in cases of CMI rupture. In another patient, partial resorption of CMI was observed at the posterior horn. The remaining four arthroscopic examinations demonstrated regeneration of meniscal-like tissue.

Clinical results achieved with CMI are promising. MRI proved to be an effective tool for monitoring the evolution of the implant and showed good correlation with clinical outcomes and arthroscopic findings at follow-up.

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.

Aims: Collagen meniscus implant (CMI) is a tissue engineering technique for the management of irreparable meniscal lesions. We report early clinical results achieved on 30 patients. The implant was also investigated by ultrastructural and biochemical analysis. Methods: Thirty patients, affected by irreparable meniscal lesions, were arthroscopically treated. Average age at the time of surgery was 38.6 years. Additional procedures included 8 ACL reconstruction, 2 high tibial osteotomy and 1 autologous chondrocyte implantation. All knees were evaluated according to the Lysholm II and Tegner activity scales. MRI was performed 6 and 12 months postoperatively. A biopsy of the implant was performed in occasion of a second arthroscopic look in two patients 6 months after surgery. The specimens, as well as the scaffold before implantation, were studied by light microscopy, TEM, SEM, EDAX microanalysis, HPLC and FACE analysis. Results: Follow up averaged 9.3 months. At 3 months, 27 patients showed an increase in the clinical scores. A progressive uniform signal was evident by MRI. Morphological analysis of the speciments showed hyaline tissue inþltrated by cells and vessels, surrounded by the scaffold þbers. At EDAX microanalysis no calciþcations were detected inside the speciments. Biochemical assays demonstrated the presence of GAG molecules of hyaluronic acid and chondroitinsulphate, that were not present in the scaffold before implantation. Conclusions: Early CMI results are promising and are supported by morphological and biochemical þndings, that indicate enhancement of new meniscal tissue by the scaffold.

Methods: The implantation procedure was performed on two male patients affected by traumatic chondral lesions, sized respectly 2.5 and 2 cm². The operations were performed through traditional artrhoscopic portals and the seeded membrane was þxed with þbrin glue. Clinical-functional evaluation was performed acc. Aims: Matrix-induced autologous chondrocyte implantation (MACÏ) is a tissue engineering technique which requires the use of a collagen membrane on which the cultured chondrocytes are seeded. We report the arthroscopic MACÏ technique for the treatment of chondral defects interesting the lateral tibial ording to ICRS score, modiþed Cincinnati knee score, IKDC, Lysholm II and Tegner scales. MRIs were taken 6 and 12 months postoperatively. Results: After one year all the clinical scores were improved in both patients. MRI showed þlling of the defects with hyaline-like tissue with reduction of subchondral bone edema. Conclusions: Even though the MACÏ technique is mostly performed with an open procedure, the site of these lesions could not be reached without sacrifying tendinous and ligamentous structures of the knee. The arthroscopic approach allowed to achieve an optimal view of the lesion and appeared the best solution for these patients. The size of these defects was too large for bone marrow stimulation techniques and/or osteochondral grafts to be successful. The development of dedicated instruments for arthroscopic MACÏ will allow to improve and simplify the surgical procedure.

During the last decade there has been an increasing interest in the management of cartilage lesions, owing to the introduction of new therapeutic options. Beside the improvement of the classical vascular techniques (mosaicplasty, microfractures, etc.), cell therapy and tissue engineering have opened new perspectives in this field. One of the most recent tissue engineering techniques is represented by the MACI‚ (Matrix-induced Autologous Chondrocyte Implantation). This method requires seeding of autologous chondrocytes on a type I-III collagene membrane, after their arthroscopy harvesting from the knee and subsequent in vitro expansion of the cellular population using autologous serum. The seeded membrane is implanted in the chondral defect using exclusively fibrin glue, through a limited exposure joint approach.

Membrane structure and its cellular population were investigated by light microscopy, SEM and electrophoresis (SDS PAGE 7%) before implantation. There was evidence of chondroblasts and type II collagen inside the seeded membrane.

Clinical series. At the Institute of Orthopaedics and Traumatology of the University of Insubria in Varese (Italy), the MACI‚ technique was used for the treatment of 13 patients, affected by chondral defects, between December 1999 and January 2001. There were 9 males and 4 females with an average age of 35 years (range, 18 to 49 years). The sites of the defects were the following: 8 medial femoral condyle, 2 lateral femoral condyle, 1 femoral trochlea, 2 talar dome. The average size of the defects was 3.5 cm2 (range, 2 to 4.5 cm2).

The clinical and functional evaluation was performed using the ICRS (International Cartilage Repair Society) rating scale, the modified Cincinnati rating system, Lysholm II and Tegner scores for the knee, while the AOFAS (American Orthopaedic Foot and Ankle Society) score was used for the ankle. MRIs were taken before the operation as well as at 6 and 12 months postoperatively.

The average follow-up was 6.5 months (range, 2 to 15 months). No complications were observed in the postoperative period. The six patients with a minimum follow-up of 6 months showed an improvement in the clinical and functional status after the operation, as testified by the scores reached with the different rating systems used. MRIs showed the presence of hyaline-like cartilage at the site of implantation.

Conclusions. According to our preliminary experience, the MACI‚ technique offers several advantages (technical simplicity, short operating times, minimal invasivity and easier access to difficult sites) and appears a reliable method for the repair of deep cartilage defects.