Impact of topography and added TiN-coating on adult human dermal fibroblasts after seeding on titanium surface in-vitro.

Complications of transcutaneous osseointegrated prosthetic systems (TOPS) focus on the metal-cutaneous interface at the stoma. Besides pain due to scare tissue as well as undefined neuropathic disorders, there is high evidence that the stoma presents the main risk causing hypergranulation and ascending infection. To restore the cutaneous barrier function in this functional area, soft-tissue on- or in-growth providing a vital and mechanically stable bio-artificial conjunction is considered a promising approach. In this study we assessed viability and proliferation of adult human dermal fibroblasts (HDFa) on modifications of a standard prosthetic titanium surface. Un-coated (TiAl6V4) as well as a titanium-nitrite (TiN) coated additive manufactured porous three-dimensional surface structures (EPORE®) were seeded with HDFa and compared to plain TiAl6V4 and polystyrene surfaces as control. Cell viability and proliferation were assessed at 24 h and 7 days after seeding with a fluorescence-based live-dead assay. Adhesion and cell morphology were analyzed by scanning electron microscopy at the respective measurements. Both EPORE® surface specifications revealed a homogenous cell distribution with flat and spread cell morphology forming filopodia at both measurements. Proliferation and trend to confluence was seen on un-coated EPORE® surfaces with ongoing incubation but appeared substantially lower on the TiN-coated EPORE® specification. While cell viability on both EPORE® specifications was comparable to plain TiAL6V4 and polystyrene controls, cell proliferation and confluence were less pronounced when compared to controls. The EPORE® topography allows for fibroblast adhesion and viability in both standard TiAl6V4 and - to a minor degree - TiN-coated specifications as a proof of principle.

Endoprosthetic replacement after extra-articular resection of bone and soft-tissue tumours around the knee.

We evaluated the clinical results and complications after extra-articular resection of the distal femur and/or proximal tibia and reconstruction with a tumour endoprosthesis (MUTARS) in 59 patients (mean age 33 years (11 to 74)) with malignant bone or soft-tissue tumours. According to a Kaplan-Meier analysis, limb survival was 76% (95% confidence interval (CI) 64.1 to 88.5) after a mean follow-up of 4.7 years (one month to 17 years). Peri-prosthetic infection was the most common indication for subsequent amputation (eight patients). Survival of the prosthesis without revision was 48% (95% CI 34.8 to 62.0) at two years and 25% (95% CI 11.1 to 39.9) at five years post-operatively. Failure of the prosthesis was due to deep infection in 22 patients (37%), aseptic loosening in ten patients (17%), and peri-prosthetic fracture in six patients (10%). Wear of the bearings made a minor revision necessary in 12 patients (20%). The mean Musculoskeletal Tumor Society score was 23 (10 to 29). An extensor lag > 10° was noted in ten patients (17%). These results suggest that limb salvage after extra-articular resection with a tumour prosthesis can achieve good functional results in most patients, although the rates of complications and subsequent amputation are higher than in patients treated with intra-articular resection.

Comparison of computed tomography and microradiography for graft evaluation after reconstruction of critical size bone defects using beta-tricalcium phosphate.

INTRODUCTION: The aim of the study was to evaluate the accuracy of computed tomography (CT) for in vivo follow up after mandibular reconstruction. MATERIAL AND METHODS: Unilateral mandibular defects were surgically created in ten sheep and either reconstructed using blood soaked beta-tricalcium phosphate (beta-TCP) cylinders (group A, n=5) or blood soaked beta-TCP cylinders that were additionally loaded with autologous bone marrow (group B, n=5). The two graft designs resulted in different stages of graft ossification representative of different stages of healing. CT datasets were fused with microradiographs and measurements of ceramic area based on both methods were compared. RESULTS: Two animals (groups A (n=1) and B (n=1)) presented infection and graft dislocation that was visible on CT and were excluded from statistical evaluation. Group A grafts underwent moderate degradation (53.55%+/-9.7) and incomplete bony incorporation representing an intermediate state of healing while ceramic grafts within group B developed a high grade of osseointegration and degradation (94.2%+/-3.3) consistent with progressive healing. Statistical comparison of measurements based on both methods revealed a significant bias (p<0.05) and a non-significant variance for group A and a significant variance (p<0.05) and non-significant bias for group B. CONCLUSION: Our results indicate that conventional CT is not suitable to objectively evaluate ossification and degradation of a beta-TCP graft in vivo and further attempts to improve clinical visualization of beta-TCP need to be undertaken.

Cartilage replacement in dogs -- A preliminary investigation of colonization of ceramic matrices.

The objective of this study was to examine the behaviour of canine chondrocytes following colonisation of a beta-tricalcium phosphate (beta-TCP, Cerasorbâ, Curasan) matrix. In total, five of these cylinders were inoculated with 1.5 ml of cell suspension and subsequently incubated for about one week. In the second part of the experiment, another five Cerasorbâ cylinders were each studded with two cartilage chips of variable size and then incubated for about one week. The series of experiments were analyzed using cell staining and imaging techniques that included scanning electron microscopy. Cell migration onto the matrix was proven for both colonisation methods. It was observed that colonising the cylinders by pipetting cell suspension on them produced far better results, with respect to both growth rate and spreading of the cells, than did colonisation by studding with cartilage chips. A homogenous, surface-covering colonisation with predominantly living cells was demonstrated by scanning electron microscopy in the chondrocyte morphology. In comparison to cell-culture controls, there was a clearly better colonisation, with cells attached to both the material's primary grains and its micropores. The ceramic studied is well accepted by canine chondrocytes, and appears to be fundamentally well-suited as a matrix for bio-artificial bone-cartilage replacement. Additional qualitative analyses and a series of experiments aiming to accelerate cell proliferation are planned for subsequent studies.

Comparison of two beta-tricalcium phosphate composite grafts used for reconstruction of mandibular critical size bone defects.

OBJECTIVE: The aim was to compare osseointegration of blood perfused beta-tricalcium phosphate cylinders (beta-TCPB) with similar composites that were additionally loaded with cancellous bone and bone marrow (beta-TCPB/BM/CB) for mandibular reconstruction. METHODS: Twelve German Black-Headed sheep with an average weight of 72.5 +/- 10 kg underwent segmental resection of the right hemi-mandible. The animals that were assigned to group A (n = 6) were reconstructed using beta-TCPB while the sheep that were assigned to group B received beta-TCPB/BM/CB grafts. Tissue quality was histologically assessed and bone-, scaffold-, cartilage- and fibrous-tissue area were estimated using semiautomated histomorphometrical software. RESULTS: Composite grafts that were loaded with bone marrow and cancellous bone (beta-TCPB/BM/CB) exhibited significant (p<0.01) higher amounts of bone formation than beta-TCPB. The patients that were assigned to group B achieved defect union and a high grade of bone maturation. Residual ceramic remnants were rare and disconnected. Bone maturity within group A was inferior and none of the specimens showed defect union. The defect centre was still occupied by a ceramic core. CLINICAL SIGNIFICANCE: Bone and bone marrow augmented beta-tricalcium phosphate composites may qualify as a promising alternative to autograft bone for mandibular reconstruction in human and veterinary medicine.

[Proximal femur replacement in revision arthroplasty]. / Der proximale Femurersatz in der Revisionsalloarthroplastik.

AIM: Today, megaendoprostheses--which were originally designed for osseous defect reconstructions in tumour surgery--are being more frequently used for extensive bone defects in revision arthroplasty. The purpose of this study was to assess the complication rate and the functional results associated with megaendoprosthesis reconstruction of the proximal femur in a non-oncological patient group. METHOD: 28 patients (average age 72; SD 10 years) with a proximal femur replacement were retrospectively (mean follow-up 43 months) evaluated regarding the complication rate. The Harris hip score was used to assess the outcome. The revision surgery was indicated because of large bone defects caused by implant-associated infection (n = 16), periprosthetic fracture (n = 8) or aseptic loosening (n = 4). RESULTS: Overall 8 patients (28.6 %) had to undergo 1 (n = 5) or more (2 n = 2, 4 n = 1) revision surgeries because of dislocation (n = 4), aseptic loosening of the stem (n = 2) and periprosthetic infection (n = 2). A significant pain relief could be achieved from on average 9.0 to 38.7 (according to the Harris hip score). All patients could be mobilised postoperatively, but walking aids were necessary for the majority of patients. CONCLUSION: A proximal femur replacement in revision arthroplasty should be regarded as a salvage procedure for restoration of extremity function. With this procedure it is possible to achieve a--limited--walking ability for patients who were immobilised preoperatively in most cases. Furthermore, pain relief can be achieved. However, the--mostly multimorbid--patients must be informed preoperatively about restrictions in daily life in order to avoid exorbitant expectations.

Frequency-specific electric response audiometry (ERA) and its clinical application in the diagnosis of hearing defects in the dog.

Reference values were established for frequency-specific electric response audiometry (ERA) in dogs on the basis of the results of ERA examinations of 200 animals with normal hearing. Air-conducting acoustic tubes with foam stoppers were used in the determination of the following: the latencies of waves I, III and V; interpeak latencies (IPL) I-III, III-V and I-V; amplitudes I and V; and the amplitude difference I-V. A frequency-specific stimulus (tone pip) was used for frequency-specific examination (1 to 4 kHz) over the entire frequency range indicated. These reference values were then used for the clinical examination of 50 dogs with hearing defects. A frequency-specific ERA was conducted and the results evaluated. These findings made it possible to draw objective conclusions about the degree, type and site of the hearing defects. Frequency-specific electric response audiometry was shown to be an important diagnostic tool for the detection of partial high- and low-frequency hearing loss and for the characterisation of hearing defects of otological, otoneurological and neurological origin.

Bioartificial bone grafting: Tarsal joint fusion in a dog using a bioartificial composite bone graft consisting of beta-tricalciumphosphate and platelet rich plasma--a case report.

Grafting of large bone defects caused by trauma or tumor resection still remains a problem to solve. In experimental studies as well as in human dentistry, osteoconduction and biodegradation of the beta-tricalciumphosphate Cerasorb as well as osteoinductive capabilities of platelet rich plasma have been proven. In case of luxation of the right tarsal joint, including a compressive fracture of the forth tarsal bone, the recommended use of autologous cancellous bone to support osseous fusion was replaced by the use of a bioartificial bone graft. Biodegradation of the bone graft was proven clinically and radiographically. Complete osseous fusion of the intertarsal joint occurred. The use of the beta-tricalciumphosphate Cerasorb in combination with platelet rich plasma to support a partial arthrodesis of the tarsal joint in a dog did not impede the healing process but led to full recovery of the patient, indicating that this concept of bioartificial bone grafting could support bone healing.

[Measurements of tibio-femoral contact area after experimental partial and subtotal meniscectomie (author's transl)]. / Tibio-femorale Kontaktflächenmessungen nach experimentellen partiellen und subtotalen Meniskektomien.

By means of section material, 24 partial and 58 subtotal meniscectomies were performed and the loss of tibio-femoral contact was evaluated by the Touchier-method planimetrically. In cases of partial resection this loss was 12% only, where as in subtotal resection 46%, where by the remaining contact zones lay in the central-, anyway meniscusfree area. The diagram of the chondral splitting lines showed a maximum of compression here, consecutively the remaining contact zone is reduced to the in earlier times most affected cartilage areas. The result correlates to the appearance of chondromalacies of the central tibial plateau in our own section cases and of postoperative osteoarthritis after subtotal meniscectomies in literature. Subtotal meniscectomies lead to incongruence and increased pressure. a pseudo-regeneration seems not to compensate the meniscus function sufficiently. A result for the clinic one should, when possible, resect menisci only partially.