Aim

The use of megaprostheses for knee reconstruction after distal femur resection in young bone sarcoma patients has become popular since early ′80. The authors reviewed their experience with different distal femur megaprostheses in children.

Short intense electrical pulses transiently increase the permeability of the cell membrane, an effect known as electroporation. This can be combined with antiblastic drugs for ablation of tumours of the skin and subcutaneous tissue. The aim of this study was to test the efficacy of electroporation when applied to bone and to understand whether the presence of mineralised trabeculae would affect the capability of the electric field to porate the membrane of bone cells.

Different levels of electrical field were applied to the femoral bone of rabbits. The field distribution and modelling were simulated by computer. Specimens of bone from treated and control rabbits were obtained for histology, histomorphometry and biomechanical testing.

After seven days, the area of ablation had increased in line with the number of pulses and/or with the amplitude of the electrical field applied. The osteogenic activity in the ablated area had recovered by 30 days. Biomechanical testing showed structural integrity of the bone at both times.

Electroporation using the appropriate combination of voltage and pulses induced ablation of bone cells without affecting the recovery of osteogenic activity. It can be an effective treatment in bone and when used in combination with drugs, an option for the treatment of metastases.

Aims: A serious problem in orthopedic surgery is the development of infections. The realization of antibacterial and biocompatible/bioactive surfaces represents a challenge. In this study antibacterial behavior has been conferred to surfaces of glasses and glass-caramics, with different degrees of bioactivity, by the introduction of silver through ion exchange.

Methods: Materials have been studied both in bulk form, and as coatings. All samples have been analyzed by means of XRD, SEM and EDS before and after the treatment. Coatings’ roughness, porosity and adhesion resistance have been also analyzed. In vitro reactivity and silver release were carried out soaking samples in SBF. Samples have been analyzed by means of SEM/ EDS and XRD; silver has been quantified in solution by GFAAS. Cellular tests have been performed in order to evaluate materials biocompatibility before and after the treatment. Antibacterial behavior has been tested against S.Aureus.

Results: Characterization analyses show that glassy or crystalline structure and morphology are maintained after the ion-exchange. As well the coating adhesion resistance is higher then the limit provided by ISO standard for hydroxyapatite coatings. GFAAS analysis determined that silver is gradually released in solution. Cellular tests demonstrate that biocompatibility is generally maintained after treatment but it is closely connected to the amount of silver released. Microbiological tests show antibacterial behavior for silver-doped samples.

Conclusions: Ion-exchange technique permits the introduction of controlled silver amount without modifying materials’ structural and morphological properties. Comparing cellular and microbiological tests it is possible to design process parameters to confer, antibacterial properties but not cytotoxic behavior.

Long-term clinical study to explore the curative effect and mechanism of the treatment of adult chronic osteomyelitis by implant Osteoset T.

The study object were 65 case adult chronic osteomyelitis patient from November 1977 to April 2003 in a University-based hospital. Age ranged from 18 to 69 years old. 40 cases were treated by general debridement (Method I); 25 cases were treated by general debridement and implant Osteoset T in dead space (Methods II). Stage IA(The UTMB Staging System) osteomyelitis 39 cases; The Organism was Staphylococcus Aureus 28 cases. In all cases (group A), 40 cases were treated with Method I (group AI), 25 cases were treated with Method II (group AII). The majority of the patients, 39 resulted as Stage IA (group B); 22 were treated with Method I (group BI) and 17 cases were treated with Method II (groupBII). Finally, 28 patients were chronic Staph Aureus osteomyelitis (Group C); 13 were treated with Method I (group CI) and 15 cases with Method II (group CII); Followed from 36 to 334 months, mean 75.0 months. Then respectively evaluate and analysis analyze the success rate of different method with standard.

The success rate of group BI was 59.09%, group BII was 94.12%, contrast the success rate there was significant difference (p< 0.05). The success rate of group AI was 60.00%, group AII was 80.00%. The success rate of group CI was 46.15%, group CII was 80.00%.

The use of Osteoset T has demostrated better healing rate than left the empty cavity there after debridement and irrigation. Osteoset T can local delivery antibiotic, filler of the dead space, It can be mixed with different antibiotics, reduces the hospitalization time, reduces the number of operation. Unfortunately, Osteoset dos not help with the bone growth.

Introduction: The use of allograft prosthetic composite (APC) of the proximal tibia offers advantages over prosthetic replacement or osteoarticular graft with a better functional outcome since the possibility of a careful soft tissue reconstruction;

Materials and Methods: From 1994 to 2002, 62 APC of the proximal tibia were performed in our department after bone tumor resection (56 malignant bone tumors, 4 cases of previously failed knee implant and 2 stage 3 benign tumors). The patients median age was 18 yrs (range: 11–77 yrs) and the mean resected length was 13.2 cm (range: 8.5–28 cm). The median follow up was 59 months (range: 13–137 months)

Results: In three patients (4,8%) a recurrence was reported at 22, 33 an 40 months and amputation was performed.

Infection was reported in 15 patients (24.2%): 2 early infections (healed with surgical debridment), 1 femoral stem septic loosening (treated with early revision with cemented stem); in 8 cases removal of the infected APC was required followed by implant of a new prosthetic device after cement spacer; two infections did not healed and patient underwent amputation; in two cases a good functional result was achieved removing the infected graft and covering the proximal tibia with cement and no other surgery was required.

Non union of the graft was observed in 8 patients (12.9%): in 4 patients autologous bone grafting was necessary to heal the osteotomy line. In other 3 cases non union was associated with graft fracture. In one case non union was associated with tibial stem loosening and revision of the whole implant was done.

Polyethylene wear was assessed in 5 patients (8%) and revision of the polyethylene components was always required.

Nine patellar tendon rupture (14.5%) were assessed and repaired was performed in seven cases.

The functional outcome of 42 patients with more than two years of follow up was excellent in 25 cases, good in 13, fair in 2 and poor in 2.

Discussion: APC of the proximal tibia is an effective alternative to osteoarticular graft and modular prosthesis because it allows good to excellent results in most of the patients (90.4%). The major concern is infection rate (24.2%) that usually lead to amputation (80%). Non union does not usually represent a problem because it’s tendency to spontaneous or bone grafting induced healing. Aseptic loosening of the tibial or femoral stem is rare. Patellar tendon rupture rate (14.5%) is similar to modular prosthetis rate and can be lowered using a femoral component with patellar groove.

Purpose of this study is to examine the long-term follow-up in prosthesis reconstruction after proximal humerus resections.

Material and methods From February 1975 to December 1990, 144 patients have been operated for a musculoskeletal tumor of the shoulder girdle with resection and reconstruction using a modular cemented prosthesis. The MRS prosthesis is assembled in three parts with a ball shaped rotating head stitched to the glenoid and acromium. Seventy patients died and 3 patients were lost to follow-up: 71 achieved a follow-up more than 10 years (123–259, av 175 mo). Age ranged from 9 to 73 years (mean 29.7). The resection was intrarticular in 44 cases, in 12 more the glenoid was resected along with the proximal humerus (extrarticular resection) and in 15 cases we performed a Tikhoff –Lindberg procedure.

Infection occurred in 7 patients (10%) from 1 to 144 months (median 12 mo): in 6 patients prosthesis removal was needed to achieve healing.

Mechanical complications were present in 19 patients (27%): 15 (21%) had prosthetic head instability (5 surgically treated), 2 breakage of the prosthetic stem and 2 prosthetic disassembly.

Results: A detailed roentgen graphic analysis has been developed to better define the long-term course of the cement bone interface. Only 3 aseptic stem loosening were detected at 1, 3 and 11 years (after a supercondylar fracture occurred 8 months before). Eighteen patients were reoperated (25%); in 4 cases with minor surgery. Failure of the system occurred in 11 cases (15%).

Conclusion: The long durability of this cemented prosthesis has been demonstrated with very few cases of stem loosening in the early follow-up time. The problem of a good prosthetic head suture is still under concerning particularly in Tikhoff-Lindberg procedure.