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.

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 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.

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.

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.