Controversies in orthopaedic oncology

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

The Megaendoprosthesis in Revision Arthroplasty - a Cost-revenue Analysis in the aG-DRG System

Megaendoprosthesis offer a viable treatment in complex revision arthroplasty cases with good functional outcome. In the context of a neoplastic indication, the diagnosis-related group (DRG) I95A is usually assigned with a relative weight of 4.906 (2021). In contrast, in revision arthroplasty, the appropriate DRG is assigned, depending on the joint replacement. The additional costs compared to the invoiced DRG are to be compensated by agreeing on hospital-specific individual fees. These complex revision arthroplasties set high technical and operative demands and are mainly performed in specialised departments. We conducted a cost-benefit analysis of the use of the megaendoprosthesis in revision cases in a specialised orthopaedic clinic, as a single centre study. The question we sought to answer was: Is cost recovery possible in the modified German DRG system (aG-DRG)?A retrospective single centre analysis of treatment costs was performed. From 2018 to 2020, 113 patients treated with a megaendoprosthesis reconstruction in a referral centre due to extensive bone loss after aseptic or septic revision of a hip or knee prosthesis were included in the study. Relevant case-related cost drivers of the aG-DRG matrix (including staff and material costs of the operating theatre area and the ward) were taken into account. The actual costs were determined according to the specifications of the calculation manual published by the German institute for the remuneration system in hospitals (InEK). For each case, the contribution margin was calculated by relating the hospital's internal costs to the corresponding cost pool of the aG-DRG matrix.According to the DRG system 2021, 17 different DRGs were used for billing - in 70% based on a patient clinical complexity level (PCCL) ≥ 4. Compared with the InEK calculation, there is a deficit of -2,901 € per case in the examined parameters. The costs of physicians show a shortfall in both the operating theatre and on the ward. Implant costs, which were supposed to be compensated by hospital-specific additional charges, show a hospital-specific shortage of -2,181 €. When analysing the risk factors for cost recovery, only these showed a significant difference.Implantation of the megaendoprosthesis in revision arthroplasty is often the last option to preserve limb function. At present, despite a high degree of specialisation and process optimisation, this treatment cannot be provided cost-effectively even in tertiary care. The politically desired specialised department structure requires sufficient reimbursement for complex cases. The economic outcome of each treatment case is often unpredictable, however the surgeon is confronted with these cases and is expected to treat them. The high standard deviation indicates large differences in the cost/revenue situation of each individual case. Our results show for the first time a realistic cost analysis for megaprosthesis in revision arthroplasty and underline the importance of an adequate hospital-specific charge, individually agreed by the funding units. The calculation should include not only the implant costs, but also the increased staff costs (increased, complex planning effort, quality management, surgery time, etc.).

[Customized partial pelvis replacement: three-dimensional planning and management concepts]

The planning and implantation of a customized partial pelvis replacement places high demands on both the surgeon and the entire team (engineer, assistants, surgical team). Thanks to careful preoperative planning and meticulous perioperative execution, customized partial pelvic replacement represents a complex but reliable procedure for defect reconstruction even with highly complex acetabular bone defects or after multiple previous surgeries.

Beyond type III Paprosky acetabular defects: are partial pelvic replacements with iliosacral fixation successful?

PURPOSE

Supra-acetabular bone loss close beyond the sciatic notch is one of the most challenging defect types for stable anatomical reconstruction in revision arthroplasty. Using reconstruction strategies from tumour orthopaedic surgery, we adapted tricortical trans-iliosacral fixation options for custom-made implants in revision arthroplasty. The aim of the present study was to present the clinical and radiological results of this extraordinary pelvic defect reconstruction.

METHODS

Between 2016 and 2021, 10 patients with a custom-made pelvic construct using tricortical iliosacral fixation (see Fig. 1) were included in the study. Follow-up was 34 (SD 10; range 15-49) months. Postoperatively CT scans evaluating the implant position were performed. Functional outcome and the clinical results were recorded.

RESULTS

Implantation was possible as planned in all cases in 236 (SD 64: range 170-378) min. Correct centre of rotation (COR) reconstruction was possible in nine cases. One sacrum screw crossed a neuroforamen in one case without clinical symptoms. During the follow-up period, four further operations were required in two patients. There were no individual implant revisions or aseptic loosening recorded. The Harris Hip Score increased significantly from 27 Pts. to 67 Pts. with a mean improvement of 37 (p < 0.005). EQ-5D developed from 0.562 to 0.725 (p = 0.038) as a clear improvement in quality of life.

CONCLUSION

Custom-made partial pelvis replacement with iliosacral fixation offers a safe solution in "beyond Paprosky type III defects" for hip revision arthroplasty. Due to meticulous planning, precise implantation with good clinical outcome can be achieved. Furthermore, the functional outcome and patient satisfaction increased significantly showing promising early results with a relatively low complication rate.

Custom-Made Metaphyseal Sleeves in "Beyond" AORI III Defects for Revision Knee Arthroplasty-Proof of Concept and Short-Term Results of a New Technique

BACKGROUND

While off-the-shelf cones and sleeves yield good results in AORI type 2 and 3 defects in revision knee surgery, massive longitudinal defects may require a proximal tibia replacement. To achieve the best anatomical as well as biomechanical reconstruction and preserve the tibial tuberosity, we developed custom-made metaphyseal sleeves (CMSs) to reconstruct massive defects with a hinge knee replacement.

METHODS

Between 2019 and 2022, 10 patients were treated in a single-center study. The indication for revision was aseptic loosening in five cases and periprosthetic joint infection in five cases. The mean number of previous revisions after the index operations was 7 (SD: 2; 4-12). A postoperative analysis was conducted to evaluate the functional outcome as well as the osteointegrative potential.

RESULTS

Implantation of the CMS in rTKA was carried out in all cases, with a mean operation time of 155 ± 48 (108-256) min. During the follow-up of 23 ± 7 (7-31) months, no CMS was revised and revisions due to other causes were conducted in five cases. Early radiographic evidence of osseointegration was recorded using a validated method. The postoperative OKS showed a significant increase (p < 0.001), with a mean score of 24 (SD: 4; range: 14-31).

CONCLUSION

Custom-made metaphyseal sleeves show acceptable results in extreme cases. As custom-made components become more and more common, this treatment algorithm presents a viable alternative in complex rTKA.

Reconstruction of Paprosky III defects with custom-made implants: do we get them in the correct position? : short-term radiological results

AIMS

The aim of this study was to examine the implant accuracy of custom-made partial pelvis replacements (PPRs) in revision total hip arthroplasty (rTHA). Custom-made implants offer an option to achieve a reconstruction in cases with severe acetabular bone loss. By analyzing implant deviation in CT and radiograph imaging and correlating early clinical complications, we aimed to optimize the usage of custom-made implants.

METHODS

A consecutive series of 45 (2014 to 2019) PPRs for Paprosky III defects at rTHA were analyzed comparing the preoperative planning CT scans used to manufacture the implants with postoperative CT scans and radiographs. The anteversion (AV), inclination (IC), deviation from the preoperatively planned implant position, and deviation of the centre of rotation (COR) were explored. Early postoperative complications were recorded, and factors for malpositioning were sought. The mean follow-up was 30 months (SD 19; 6 to 74), with four patients lost to follow-up.

RESULTS

Mean CT defined discrepancy (Δ) between planned and achieved AV and IC was 4.5° (SD 3°; 0° to 12°) and 4° (SD 3.5°; 1° to 12°), respectively. Malpositioning (Δ > 10°) occurred in five hips (10.6%). Native COR reconstruction was planned in 42 cases (93%), and the mean 3D deviation vector was 15.5 mm (SD 8.5; 4 to 35). There was no significant influence in malpositioning found for femoral stem retention, surgical approach, or fixation method.

CONCLUSION

At short-term follow-up, we found that PPR offers a viable solution for rTHA in cases with massive acetabular bone loss, as highly accurate positioning can be accomplished with meticulous planning, achieving anatomical reconstruction. Accuracy of achieved placement contributed to reduced complications with no injury to vital structures by screw fixation.Cite this article: Bone Joint J 2022;104-B(10):1110-1117.

[Quality in Revision Arthroplasty: A Comparison between Claims Data Analysis and External Quality Assurance]

BACKGROUND

External quality assurance for revisions of total knee arthroplasty (TKA) and total hip arthroplasty (THA) are carried out through the AQUA institute in Germany. Data are collected by the providers and are analyzed based on predefined quality indicators from the hospital stay in which the revision was performed. The present study explores the possibility to add routine data analysis to the existing external quality assurance (EQS). Differences between methods are displayed. The study aims to quantify the benefit of an additional analysis that allows patients to be followed up beyond the hospitalization itself.

MATERIAL AND METHODS

All persons insured in an AOK sickness fund formed the population for analysis. Revisions were identified using the same algorithm as the existing external quality assurance. Adverse events were defined according to the AQUA indicators for the years 2008 to 2011.The hospital stay in which the revision took place and a follow-up of 30 days were included. For re-operation and dislocation we also defined a 365 days interval for additional follow-up. The results were compared to the external quality control reports.

RESULTS

Almost all indicators showed higher events in claims data analysis than in external quality control. Major differences are seen for dislocation (EQS SD: 1.87 vs. claims data [cd] SD: 2.06 %, cd+30 d: 2.91 %, cd+365 d: 7.27 %) and reoperation (hip revision: EQS SD: 5.88 % vs. claims data SD: 8.79 % cd+30 d: 9.82 %, cd+365 d: 15.0 %/knee revision: EQS SD: 3.21 % vs. claims data SD: 4.07 %, cd+30 d: 4.6 %, cd+365 d: 15.43 %). Claims data could show additional adverse events for all indicators after the initial hospital stay, rising to 77 % of all events.

CONCLUSIONS

The number of adverse events differs between the existing external quality control and our claims data analysis. Claims data give the opportunity to complement existing methods of quality control though a longer follow-up, when many complications become evident.

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.

Pelvic reconstruction with compound osteosynthesis following hemipelvectomy: A clinical study

To date, all surgical techniques used for reconstruction of the pelvic ring following supra-acetabular tumour resection produce high complication rates. We evaluated the clinical, oncological and functional outcomes of a cohort of 35 patients (15 men and 20 women), including 21 Ewing's sarcomas, six chondrosarcomas, three sarcomas not otherwise specified, one osteosarcoma, two osseous malignant fibrous histiocytomas, one synovial cell sarcoma and one metastasis. The mean age of the patients was 31 years (8 to 79) and the latest follow-up was carried out at a mean of 46 months (1.9 to 139.5) post-operatively. We undertook a functional reconstruction of the pelvic ring using polyaxial screws and titanium rods. In 31 patients (89%) the construct was encased in antibiotic-impregnated polymethylmethacrylate. Preservation of the extremities was possible for all patients. The survival rate at three years was 93.9% (95% confidence interval (CI) 77.9 to 98.4), at five years it was 82.4% (95% CI 57.6 to 93.4). For the 21 patients with Ewing's sarcoma it was 95.2% (95% CI 70.7 to 99.3) and 81.5% (95% CI 52.0 to 93.8), respectively. Wound healing problems were observed in eight patients, deep infection in five and clinically asymptomatic breakage of the screws in six. The five-year implant survival was 93.3% (95% CI 57.8 to 95.7). Patients were mobilised at a mean of 3.5 weeks (1 to 7) post-operatively. A post-operative neurological defect occurred in 12 patients. The mean Musculoskeletal Tumor Society score at last available follow-up was 21.2 (10 to 27). This reconstruction technique is characterised by simple and oncologically appropriate applicability, achieving high primary stability that allows early mobilisation, good functional results and relatively low complication rates.

The influence of elementary silver versus titanium on osteoblasts behaviour in vitro using human osteosarcoma cell lines

Purpose. The antimicrobial effect of a silver-coated tumor endoprosthesis has been proven in clinical and experimental trials. However, in the literature there are no reports concerning the effect of elementary silver on osteoblast behaviour. Therefore, the prosthetic stem was not silver-coated because of concerns regarding a possible inhibition of the osseointegration. The aim of the present study was to investigate the effect of 5–25 mg of elementary silver in comparison to Ti-6Al-4V on human osteosarcoma cell lines (HOS-58, SAOS). Methods. Cell viability was determined by measuring the MTT proliferation rate. Cell function was studied by measuring alkaline phosphatase (AP) activity and osteocalcine production. Results. In the HOS-58 cells, the AP activity was statistically significant (P < 0.05) higher at a supplement of 5–10 mg of silver than of Ti-6 Al-4V at the same doses. For both cell lines, a supplement above 10 mg of silver resulted in a reduced AP activity in comparision to the Ti-6 Al-4V group, but a statistically significant difference (P < 0.05) was observed at a dose of 25 mg for the SAOS cells only. At doses of 20–25 mg in the HOS-58 cells and 10–25 mg in the SAOS cells, the reduction of the proliferation rate by silver was statistically significant (P < 0.05) compared to the Ti-6 Al-4V supplement. Discussion. In conclusion, elementary silver exhibits no cytotoxicity at low concentrations. In contrast, it seems to be superior to Ti-6 Al-4V concerning the stimulation of osteogenic maturation at these concentrations, whereas at higher doses it causes the known cytotoxic properties.

Bisphosphonate treatment of aggressive primary, recurrent and metastatic Giant Cell Tumour of Bone

Background

Giant cell tumour of bone (GCTB) is an expansile osteolytic tumour which contains numerous osteoclast-like giant cells. GCTB frequently recurs and can produce metastatic lesions in the lungs. Bisphosphonates are anti-resorptive drugs which act mainly on osteoclasts.

Method

In this study, we have examined clinical and radiological outcomes of treatment with aminobisphosphonates on 25 cases of aggressive primary, recurrent and metastatic GCTB derived from four European centres. We also analysed in vitro the inhibitory effect of zoledronic acid on osteoclasts isolated from GCTBs.

Results

Treatment protocols differed with several different aminobisphosphonates being employed, but stabilisation of disease was achieved in most of these cases which were refractory to conventional treatment. Most inoperable sacral/pelvic tumours did not increase in size and no further recurrence was seen in GCTBs that had repeatedly recurred in bone and soft tissues. Lung metastases did not increase in size or number following treatment. Zoledronic acid markedly inhibited lacunar resorption by GCTB-derived osteoclasts in vitro.

Conclusion

Our findings suggest that bisphosphonates may be useful in controlling disease progression in GCTB and that these agents directly inhibit GCTB - derived osteoclast resorption. These studies highlight the need for the establishment of standardised protocols to assess the efficacy of bisphosphonate treatment of GCTB.

Morphologic characterization of osteosarcoma growth on the chick chorioallantoic membrane

Background

The chick chorio-allantoic membrane (CAM) assay is a commonly used method for studying angiogenic or anti-angiogenic activities in vivo. The ease of access allows direct monitoring of tumour growth by biomicroscopy and the possibility to screen many samples in an inexpensive way. The CAM model provides a powerful tool to study effects of molecules, which interfere with physiological angiogenesis, or experimental tumours derived from cancer cell lines. We therefore screened eight osteosarcoma cell lines for their ability to form vascularized tumours on the CAM.

Findings

We implanted 3-5 million cells of human osteosarcoma lines (HOS, MG63, MNNG-HOS, OST, SAOS, SJSA1, U2OS, ZK58) on the CAM at day 10 of embryonic development. Tumour growth was monitored by in vivo biomicroscopy at different time points and tumours were fixed in paraformaldehyde seven days after cell grafting. The tissue was observed, photographed and selected cases were further analyzed using standard histology.

From the eight cell lines the MNNG-HOS, U2OS and SAOS were able to form solid tumours when grafted on the CAM. The MNNG-HOS tumours showed the most reliable and consistent growth and were able to penetrate the chorionic epithelium, grow in the CAM stroma and induce a strong angiogenic response.

Conclusions

Our results show that the CAM assay is a useful tool for studying osteosarcoma growth. The model provides an excellent alternative to current rodent models and could serve as a preclinical screening assay for anticancer molecules. It might increase the speed and efficacy of the development of new drugs for the treatment of osteosarcoma.

Improvement of the soft socket after rotationplasty: a single case study

Rotationplasty is established as a functionally improving and partially ablative method of tumour surgery, but good clinical and functional results do not only depend on a successful surgery. Due to the changed biomechanical situation the activity level is limited by the weight bearing capacity of the rotated foot. Painful blisters and callosities may limit the use of the exo-prosthesis, because the skin is overstressed in the soft socket. A 28-year-old patient with a rotationplasty type A2 suffered from painful callosities of the rotated foot. Capacitive pressure measurements were performed as well as a gait analysis for kinematics and kinetic characteristics. Clinically a decrease of the callosities and a pain relieve was obvious and the patient learned skiing without prior knowledge. Biomechanically a decrease of the peak pressure (from 240.6-135.0 kPa) and the mean pressure (from 83.2-66.2 kPa), was observed with an increased weight bearing area. The study has shown that a modification of the heel bench can considerably improve pressure distribution. An increase of the load bearing area appears to enable the skin to compensate even intensive strain during athletic activities.

Biological importance of a polymorphic CA sequence within intron 1 of the epidermal growth factor receptor gene (EGFR) in high grade central osteosarcomas

Expression of EGFR in high grade osteosarcomas has been observed to be correlated with an improved prognosis. Yet, the underlying mechanism remained unclear since amplifications of EGFR have rarely been described. Recently, the length of a polymorphic CA repeat located at a 5'-regulatory sequence in the intron 1 of the EGFR gene (SSR I) has been shown to be associated with its basal transcriptional activity. We therefore determined the allelic length of CA SSR-I in 219 cases of high grade osteosarcoma and correlated the results with EGFR expression in 34 cases, the presence of amplifications within the CA SSR-I repeat in 59 cases, and clinical follow-up. Our results confirm that in osteosarcoma patients short alleles are more frequent than longer ones, 16 CA repeats being the most frequent. The allele composition differed significantly from the one recently described in a healthy control population (P < 0.01). Short alleles tended to be associated with increased expression of EGFR. Amplifications of the EGFR gene were seen in 13.5% of cases. Significant correlations between allele length composition and neoadjuvant chemotherapy response or long term clinical outcome could not be established. While we were able to show that high frequency of EGFR expression in osteosarcomas is associated with predominantly short alleles of EGFR-CA SSR I, persisting shortcomings in the correspondence with clinical data point toward the existence of additional, putatively more important transcription control mechanisms for EGFR in osteosarcomas which might account for the good prognostic value of EGFR expression.

Giant cell tumor of bone: treatment and outcome of 214 cases

BACKGROUND

Two hundred and fourteen patients with benign giant cell tumor of bone (GCTB), treated from 1980 to 2007 at the Department of Orthopedics of the University of Muenster (Germany), were analyzed in a retrospective study.

PATIENTS AND METHODS

The mean age was 33.3 years with a female-to-male ratio of 1.2 : 1. The mean follow up was 59.8 months. The recurrence rate of patients who received first treatment at our institution was 16.6%. The most common primary treatment was curettage (188 patients) usually followed by adjuvant local therapy. The effects of bone cement (PMMA), burring and hydrogen peroxide (H(2)O(2)) were statistically analyzed and the influence of a subchondral bone graft on the recurrence rate was evaluated.

RESULTS

PMMA alone (n = 52) reduces the likelihood of recurrence by the factor 8.2, additional high-speed burring (n = 39) by the factor 3.9 (compared to PMMA only). H(2)O(2) (n = 42) seems to have an additional effect comparable to that of phenol although it did not reach statistical significance.

CONCLUSION

The combination of all adjuncts (PMMA, burring, H(2)O(2) - n = 42) reduces the likelihood of recurrence by the factor 28.2 compared to curettage only and therefore should be recommended as a standard treatment. If the tumor reaches close to the articulating surface a subchondral bone graft (n = 42) can be performed without risking a higher recurrence rate. We add seven cases of pulmonary metastases and two cases of multicentricity to the literature. Bisphosphonates and interferon alpha may have a beneficial effect.

Epidermal growth factor receptor expression in high-grade osteosarcomas is associated with a good clinical outcome

PURPOSE

The expression of the epidermal growth factor receptor (EGFR) in osteosarcomas has repeatedly been described. With the introduction of anti-EGFR-targeted therapies in clinical practice, these findings regain increased attention. Experience with anti-EGFR-targeted therapies in other cancers has made clear that besides the expression status of EGFR, a detailed knowledge about gene mutations is of major predictive power. We therefore aimed to explore the EGFR expression and gene mutation status in high-grade osteosarcomas.

EXPERIMENTAL DESIGN

We investigated tumor samples of osteosarcoma patients of all age groups by means of immunohistochemistry (n=111) and egfr fluorescence in situ hybridization (n=39). Sixty-three patients were treated according to the Cooperative Osteosarcoma Study Group protocols and complete clinical follow-up was available in these cases.

RESULTS

Ninety-one of 111 (81%) of osteosarcomas revealed an expression of EGFR. EGFR expression showed a dose-response relation with improved event-free and overall survival. This was independent of the degree of tumor regression due to neoadjuvant chemotherapy. Nine of 39 (23%) osteosarcomas showed egfr amplifications by means of fluorescence in situ hybridization. All these cases expressed EGFR. When comparing EGFR expression between primary biopsy and resection specimen (n=19), viable residual tumor cells in resection specimens revealed a lower EGFR expression and a tendency toward membranous staining compared with the initial biopsy.

CONCLUSIONS

In conclusion, expression and amplification of EGFR are frequently observed in high-grade osteosarcomas and are associated with improved prognosis in a dose-responsive way. This implies that low EGFR expression possibly predicts lack of response to conventional treatment in high-grade osteosarcomas and may warrant a more intensive therapeutic approach, although not based on EGFR targeting.

Expression of beta-catenin and p53 are prognostic factors in deep aggressive fibromatosis

AIMS

To determine the prognostic significance of beta-catenin in aggressive fibromatosis and to identify potential molecular markers for new targeted therapies.

METHODS AND RESULTS

A tissue microarray of 37 cases of deep aggressive fibromatosis was constructed and subjected to immunohistochemical analysis for beta-catenin, p53, smooth muscle actin (SMA), desmin, Ki67, c-erbB2, epidermal growth factor receptor (EGFR), c-kit, CD34 and S100. Complete clinical follow-up was available for 23 patients. Nuclear beta-catenin expression was associated with an increased rate of local tumour recurrence (60.0% 1-year and 0% 5-year event-free survival; P < 0.05). Furthermore, p53 expression was associated with an increased risk of tumour recurrence (50% 1-year event-free survival rate and 0% 5-years event-free survival rate, P < 0.05). The coexpression of p53 and beta-catenin was significantly correlated (P < 0.05). No statistically significant association was seen between MIB1 and p53 or beta-catenin expression, respectively. No expression of EGFR, c-erbB2 or c-kit was seen.

CONCLUSIONS

The overexpression of beta-catenin and p53 is associated with a decreased event-free survival in deep aggressive fibromatosis. Further studies are required to establish whether these findings can lead to an improvement in the treatment of this rare neoplasm.

Lack of toxicological side-effects in silver-coated megaprostheses in humans

Deep infection of megaprostheses remains a serious complication in orthopedic tumor surgery. Furthermore, reinfection gets a raising problem in revision surgery of patients suffering from infections associated with primary endoprosthetic replacement of the knee and hip joint. These patients will need many revision surgeries and in some cases even an amputation is inevitable. Silver-coated medical devices proved their effectiveness on reducing infections, but toxic side-effects concerning some silver applications have been described as well. Our study reports about a silver-coated megaprosthesis for the first time and can exclude side-effects of silver-coated orthopedic implants in humans. The silver-levels in the blood did not exceed 56.4 parts per billion (ppb) and can be considered as non-toxic. Additionally we could exclude significant changes in liver and kidney functions measured by laboratory values. Histopathologic examination of the periprosthetic environment in two patients showed no signs of foreign body granulomas or chronic inflammation, despite distant effective silver concentrations up to 1626 ppb directly related to the prosthetic surface. In conclusion the silver-coated megaprosthesis allowed a release of silver without showing any local or systemic side-effects.

The effect of rotationplasty on the ankle joint: long-term results

In patients with rotationplasty the biomechanical conditions in the ankle joint are altered dramatically. By displacement and reduction of the weight-bearing area of the joint, the stress affecting its cartilage is increased. The use of an exoprothesis results in skin and soft tissue irritation. Due to these biomechanical changes, a prearthrotic deformity or skin problems could be expected. The current study examines changes in 21 patients treated with rotationplasty (mean follow-up 13.5 years) because of a malignant bone tumour or a femoral segmental defect. Local tenderness, skin and soft tissue changes, problems with exoprostheses, and pain was assessed by clinical examination and documented. Osseous changes were evaluated by plain X-ray. A MRI-scan was also obtained in five patients. Hardened skin and blisters were located at the main loading areas of the rotated foot. These changes could be reduced by optimizing the exoprosthetic fit. Radiographically, a slight asymptomatic attenuation of the articular space was observed in four patients and a slight coexistent subchondral sclerosis with small osteophytes in one patient. No degenerative changes were observed on X-ray and no cartilaginous changes were observed on MRI. The results suggest that the foot is able to adapt to the load changes after this procedure and that rotationplasty does not cause an inevitable arthrosis in the ankle joint.

[Cartilage tumours of the bone. Diagnosis and therapy]

Primary malignant bone tumours are rare. The annual incidence of these tumours is 10 per 1 million. Nearly 30% of the primary malignant bone tumours are malignant cartilage tumours. The frequency of benign cartilage tumours cannot be definitely estimated because these tumours are normally clinically inapparent and therefore often diagnosed as an incidental finding. The cartilage tumours appear as benign lesions (e.g. chondroma), as borderline tumours (proliferative chondroma vs grade I chondrosarcoma) or as highly malignant chondrosarcoma (e.g. dedifferentiated chondrosarcoma). Commensurate with the different clinical and oncological manifestations of the cartilage tumours, there are wide differences in the treatment and clinical course of the individual tumour. This article discusses the problems in the diagnosis and treatment of cartilage tumours from an orthopaedic point of view.

The potential of comparative genomic hybridization as a tool in the differential diagnosis of matrix-producing bone lesions

Matrix-producing bone lesions consist of a wide variety of benign and malignant conditions. With respect to morphology, an overlap exists between benign and malignant bone tumors that causes difficulties in the final determination of the tumor. This study was conducted to show the potential of comparative genomic hybridization as a tool in the differential diagnosis of matrix-producing bone lesions. Thirty benign bone tumors were evaluated by conventional comparative genomic hybridization. To test its diagnostic reliability, 5 additional cases were analyzed, all with differential diagnostic difficulties related to morphology and radiology. All were ultimately diagnosed as malignant sarcomas, and unbalanced alterations were detected. In contrast benign tumors or tumor-like lesions did not reveal any chromosomal alterations. Comparative genomic hybridization is a useful adjunct in the complicated differential diagnostic algorithms of matrix-producing bone tumors.

Endoprosthetic reconstruction in 250 patients with sarcoma

We assessed the clinical results and complications associated with a new endoprosthetic replacement system (Mutars) used in 250 patients with a malignant bone or soft tissue tumor. The key features of the system are its cementless, hexagonal-shaped stem (titanium alloy), the possibility of torsion adjustments in 5 degrees -increments, and the Trevira tube for soft tissue attachment. The mean age of the patients was 30.7 years, and the mean followup was 45 months. Prosthetic survival at 5 years was 89.7% for the upper extremity and 68.5% for the lower extremity. Prosthetic survival without any reoperation was 73.4% at 3 years postoperatively and 60.4% at 5 years postoperatively. Prosthetic failure was caused by deep infection in 12% (30 patients) of patients and aseptic loosening in 8% (20 patients) of patients. Stem fracture occurred in only 1.6% (four patients) of patients. Dislocation rates were reduced by using the Trevira tube. Limb survival was achieved in 82.6% to 93.1% of patients depending on the endoprosthetic replacement site, and functional results ranged between 63% to 83% according to the Tumor Society score. Our results suggest limb salvage with the Mutars endoprosthesis is successful with good functional results.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series).

Free vascularized fibular grafting for reconstruction after tumor resection in the upper extremity

BACKGROUND

Limb salvage is viable in the majority of patients with malignant bone tumors, but especially in case of extensive tumors and bad soft tissue conditions, it is challenging in upper extremity.

OBJECTIVES/METHOD

The clinical and radiological results of 21 patients, who had free vascularized fibular grafts (VFG), for diaphyseal (14), and epipyseal (7) defect reconstruction of the upper extremity, are presented. The indications for VFG were resection after osteosarcoma (9 cases), Ewings sarcoma (9 cases), chondrosarcoma (1 case), rhabdomyosarcoma (1 case), and 1 case of fibrous dysplasia. The 20 malignant tumors were staged as follows: 2a (1), 2b (18), 3 (1). The mean follow-up was 43.6 months (min 6.0-max 131.9). Functional results were described and graded quantitatively according to the MSTS-score.

RESULTS

Results were satisfactory with regard to pain, emotional acceptance, manual dexterity, and function. Lifting ability was decreased in two patients. Hypertrophy index was 31% (min 13%-max 71%). Main complications were fracture (5), pseudoarthrosis (4), prolonged wound healing (4), temporary nerve irritation (2), and deep infection (1). Re-operation was required in eight patients (12 operations).

CONCLUSION

VFG offers a good possibility for biological reconstruction of large skeletal defects, with an acceptable complication and re-operation rate. When conservative treatment of complications was not successful, further surgery led to recovery in the majority of cases.

Characteristics and outcome of infections associated with tumor endoprostheses

INTRODUCTION

Infection associated with prosthesis used after tumor resection is a common and serious complication. The purpose of the current retrospective study was to describe the course of infection in patients with a tumor endoprosthesis and the determination of risk factors associated with failed limb salvage.

MATERIAL AND METHODS

30 patients with an infection associated with a tumor endoprosthesis were investigated with regard to treatment strategies, number and type of revision operations, duration of hospital stay, determination of risk factors associated with failed limb salvage and final outcome.

RESULTS

Limb salvage related to the complication infection was achieved in 19 patients (63.3%). Two-stage reimplantation of an endoprosthesis was successful in 14 patients but subsequently failed in one patient. Out of 11 patients where limb salvage failed, an amputation was performed in 6 patients, a rotationplasty in 4, and stump lengthening procedure in 1 patient. A poor soft tissue condition was a significant (P<0.05) risk factor for failed limb salvage. No patient receiving chemotherapy with a poor soft tissue condition had limb salvage surgery. The mean number of revision operations per patients was 2.6. The mean duration of hospital stay was 68 days.

CONCLUSION

Infection associated with prosthesis is a serious complication and is involved with long hospitalization. Limb salvage failed mostly in the case of a poor soft tissue condition. In these cases repeated revision surgery should be avoided and ablative surgery recommended at an early stage. Rotationplasty is an alternative to amputation in the case of an infection of the proximal or distal part of the femur.

Functional results and quality of life after treatment of pelvic sarcomas involving the acetabulum

BACKGROUND

Limb salvage after resection of a pelvic sarcoma that involves the acetabulum represents a surgical challenge. The ideal method of reconstruction after acetabular resection remains a subject of controversy, and the outcome in terms of the impact of therapy is still unknown. The purpose of this study was to determine the impact of surgery on health-related quality of life and function after acetabular resection.

METHODS

Eighty-one patients with a pelvic sarcoma underwent acetabular resection at a single institution. Functional evaluation and quality-of-life examination were performed in forty-five patients, and these patients comprised the study group. Quality of life was assessed with use of the European Organization for Research and Treatment of Cancer core quality-of-life questionnaire. Function was assessed with use of the Musculoskeletal Tumor Society system.

RESULTS

The median age of the patients was 30.4 years at the time of the acetabular resection and 35.7 years at the time of follow-up. The median time interval from the index operation to the latest follow-up was sixty-nine months. At the latest follow-up evaluation, the mean functional status score was 14.5 points of a maximum of 30 points. In a comparison of endoprosthetic replacement and hip transposition following resection, significantly better functional results (p = 0.017) and a lower number of complications were found in patients who had a hip transposition. Quality-of-life assessment results were also better in patients with a hip transposition, especially in role functioning (p = 0.043).

CONCLUSIONS

On the basis of the low complication rate and the good functional and quality-of-life results, hip transposition after acetabular resection seems to be the optimal technique for treating patients with a pelvic sarcoma involving the acetabulum.

Sonographic findings of hibernoma. A report of two cases

We present 2 cases of hibernoma, a rare lipomatous tumor arising from brown fat tissue. In each case, a hyperechoic mass in comparison to surrounding musculature combined with elevated vascularization was highly suggestive of a liposarcoma. As a rule, malignancy cannot be excluded safely by imaging modalities, and a preoperative biopsy should be performed. Although rare, hibernomas should be considered in the differential diagnosis of lipomatous soft-tissue tumors.

Treatment of primary malignant bone tumours of the distal tibia

We treated 15 patients with primary malignant bone tumours of the distal tibia of which 14 were treated by limb salvage surgery. Reconstructions were done by allografts with or without microvascular fibula transfer, by bone transport, by fibula transfer alone or by endoprosthetic replacement. The most successful methods were bone transport and endoprosthetic replacement. However, serious complications with deep infections leading to secondary amputation occurred in four patients and in all reconstruction groups. After a mean follow up of 7 years, no local recurrence occurred, and all patients were alive and free of disease. After radical resection, bone transport in defects less than 15 cm is a viable option. In larger defects in children, allograft with vascularised fibula is an acceptable alternative, but amputation still has a role in this group. In adults, endoprosthetic replacement with proper soft tissue coverage is a viable option in cases with large bony defects.

Endoprosthetic replacement of the humerus combined with trapezius and latissimus dorsi transfer: a report of three patients

INTRODUCTION

To improve the functional outcome after proximal and/or total humerus replacement, we combined the surgical procedures described by Bateman and Gerber.

MATERIALS AND METHODS

In three patients after wide tumor resection, endoprosthetic replacement with a modular tumor endoprosthesis (MUTARS System) was performed. In addition to a capsular and muscular reconstruction using the Trevira tube, a trapezius transfer onto the Trevira tube in combination with a latissimus dorsi transfer onto the Trevira tube was performed. The patients were immobilized for 6 weeks after surgery with an abductor cast.

RESULTS

After a follow-up of 1 year, there was no significant improvement of the shoulder function in comparison with patients who did not undergo the combined muscle transfer (control group n=16: mean abduction 37.5 degrees ; mean anteversion 35.0 degrees ; mean internal rotation 15.2 degrees ; mean external rotation 25.2 degrees ).

CONCLUSION

In our patients, the combination of the Gerber and the Bateman procedures did not improve the shoulder function in patients with proximal and/or total humerus replacements. Therefore, the functional results do not justify two separate approaches and a prolonged operation time.

219 METHYLATION STATUS OF A DIFFERENTIALLY METHYLATED REGION (DMR) WITHIN THE BOVINE Igf2 GENE IN PREIMPLANTATION EMBRYOS

Specific DNA regions within imprinted genes become differentially methylated on the maternal and paternal chromosomes during germ cell development. These DMRs play a crucial role in the regulation of imprinted gene expression. The murine insulin-like growth factor2 gene (Igf2) is imprinted and contains an intragenic DMR within the last exon. Recently it became known that the bovine Igf2 gene is also imprinted (Dindot et al. 2004 Biol. Reprod. 71, 470–478) where we have now identified an intragenic DMR in the last exon with the paternal allele being methylated. Aberrant methylation patterns within the bovine Igf2 gene could result in deregulated gene expression and could therefore be involved in the development of fetal abnormalities such as the large offspring syndrome (LOS) in cattle. We have studied the methylation status of 27 CG dinucleotides within this DMR in bovine pre-implantation embryos of different origin by bisulfite sequencing. DNA was isolated from expanded blastocysts collected in vivo and generated by in vitro fertilization (IVF), somatic nuclear transfer (NT), and parthenogenesis (PA). Additionally, DNA was obtained from fibroblasts derived from a female and a male adult animal and used as donor cells for NT and from zygotes and 4-cell embryos both produced by IVF. After PCR amplification of the bisulfite-treated DNA, PCR products were cloned and sequenced. Methylation percentages were calculated for each individual clone by division of the 27 CpGs with the number of methylated CpGs per sample. The methylation levels (%) from each sample were then used to obtain the global methylation levels of the analyzed region. Methylation decreased during the transition from the zygote (28.4% ± 3.8 SEM) to the 4-cell embryo (6.3% ± 2.2 SEM) indicating that the DMR is demethylated after fertilization. An increased methylation level was observed in expanded blastocysts (in vivo: 10.2% ± 1.2 SEM; IVF: 10.1% ± 0.7 SEM; female NT: 12.4% ± 1.4 SEM). Thus, remethylation starts before the blastocyst stage. The higher methylation level of male NT blastocysts (22% ± 1.9 SEM) in comparison to their in vivo and IVF counterparts could be due to an insufficient reprogramming of the donor cells after nuclear transfer. Female and male donor cells were both heavily methylated (77% ± 2.2 SEM; 72% ± 2.9 SEM, respectively). Parthenogenetic expanded blastocysts were less methylated (2.3% ± 1 SEM), probably due to their diploid maternal genome. Results show for the first time that the methylation status at this DMR is associated with the origin of the embryo. Analysis of methylation patterns in pre-implantation embryos could provide a diagnostic tool to unravel mechanisms involved in fetal malformations often observed after the use of in vitro fertilization and/or nuclear transfer.

Primary multifocal osseous Hodgkin disease: a case report and review of the literature

PURPOSE

Hodgkin disease (HD) typically involves the lymphatic system at one or more sites. Rarely, Hodgkin disease presents as an osseous lesion without involvement of lymph nodes. Therefore, the histologic diagnosis of osseous HD can be problematic. We present a rare case of multifocal osseous HD and a review the literature with special emphasis on treatment and prognosis.

METHODS

Osteomyelitis and lymphoma are the main differential diagnoses and can only be excluded histologically by the presence of Sternberg Reed cells or by immunohistochemical examinations. This case reports a 21-year old man with a Hodgkin lymphoma located at the proximal femur and the proximal tibia.

RESULTS

Staging studies revealed no other tumor manifestations. Regarding the Ann Arbor classification, the presented case should be a stage IV disease. The patient is without evidence of disease 4 years after curettage, local radiation therapy, and systemic chemotherapy despite the poor prognosis considering the Ann Arbor classification.

CONCLUSION

Reviewing the few reported cases, osseous HD must be distinguished from systemic HD with diffuse bone marrow involvement and from osseous metastases in advanced stage of disease because it seems to have a better prognosis.

Chondroblastoma of the acromion mimicking fibrous dysplasia

The authors report the case of a 65-year-old man who presented with an expansive osteolytic lesion in the right acromion, mimicking cystic fibrous dysplasia. Magnetic resonance imaging showed a lesion with intermediate-signal intensity on T1-weighted images and a high-signal intensity on fat suppressed T2-weighted images. The biopsy led to the diagnosis of chondroblastoma. This tumour is rare in flat bones, and may mimic other benign or malignant lesions. It is therefore essential to perform a biopsy in order to obtain a definite diagnosis. The acromion was excised, and replaced with an iliac crest graft.

245RELATIVE ABUNDANCE OF HSP 70 MRNA IN BOVINE EMBRYOS PRODUCED IN VITRO USING DIFFERENT EMBRYO/VOLUME RATIOS IN CULTURE

In spite of in vitro embryo production systems having been greatly improved over recent years, employing a variety of culture conditions (media, protein sources, gas atmosphere, etc.), we still do not know much about the real necessity of embryos to develop under the same conditions as occur in vivo. These differences between in vivo and in vitro culture at preimplantation embryonic stages can produce deviations in gene expression and in normal fetal development (large offspring syndrome). Heat shock proteins (Hsp) are engaged in cell response to regulatory signals or perturbations in the microenviroment and can be used as a sensitive indicator of stress caused by suboptimal culture conditions (Wrenzycki et al., 2001Hum. Reprod. 16, 893–901). Hsp act as chaperones in facilitating protein folding and assembly and stabilize damaged proteins to prevent aggregation of fragments, thereby allowing repair or degradation. The aim of the present study was to investigate the effects of different embryo/volume ratios on bovine embryo development and the relative abundance of Hsp 70.1 gene transcripts. In this experiment, oocytes were isolated from slaugterhouse ovaries and matured, fertilized and cultured in groups of 5, 10, 20 or 30 per each drop of 100μL. The oocytes were matured in TCM 199 supplemented with 0.4% BSA. After maturation, oocytes were fertilized in TALP medium, using frozen/thawed sperm, selected using a percoll density gradient. The zygotes were cultured to the morula or Day 7 blastocyst stage employing SOF supplemented with 0.4 % BSA. Developmental check points were cleavage rate (Day 3pi), blastocyst formation (Day 8pi) and hatching (Day 11pi). A semi-quantitative RT-PCR assay was used to determine the relative levels of gene transcripts in single embryos at morula (Day 6) and blastocyst (Day 7) stages (Wrenzycki et al., 2001 Biol. Reprod. 65, 309–317). Data of cleavage, blastocyst formation and hatching rates were analyzed using chi-square test. Relative abundance (RA) of Hsp 70.1mRNA were compared in tested groups using ANOVA followed a Tukey test. Differences at P&lt;0.05 were considered significant. Results show that no significative difference in hatching rate per blastocyst produced was detected among the four groups. Cleavage rate and blastocyst formation were significantly higher in groups with 5, 10 and 20 embryos compared with drops containing 30 embryos. Hsp transcripts were detected in morula and blastocyst stages in all groups. In morula stage, no differences were observed in the RA of Hsp 70.1mRNA among groups with 5, 10, 20 and 30 embryos cultured per drop. However, in blastocyst stage, the RA was significantly increased in the group with 20 embryos per drop as compared to the group with 5 embryos. The results show that different embryo/volume ratios in culture influence not only cleavage rate, blastocyst formation and hatching rate, but also expression of Hsp 70.1 gene. Further studies changing other culture conditions and using in vivo-derived bovine embryos will aid in elucidating which culture systems are ideal to produce bovine embryos in vitro. This research was supported by CAPES/DAAD program and CNPq.

234IMPRINTING STATUS OF DEVELOPMENTALLY IMPORTANT GENES IN BOVINE PREIMPLANTATION EMBRYOS

Several imprinted genes have been identified in different species such as mouse and man but in cattle imprinting has only been confirmed for the Insulin-like growth factor 2 receptor gene (Igf2r). DNA methylation is one of the most common mechanisms of imprinting. Imprinting is correlated with the methylation of normally unmethylated CpG islands, and aberrations in methylation are thought to be involved in the Large Offspring Syndrome (LOS) which is frequently observed in offspring derived from in vitro-produced and/or cloned embryos. The imprinting of the bovine Insulin-like growth factor 2 gene (Igf2), the Igf2r gene and the Mammalian achaete scute homologue 2 gene (Mash2) was analyzed in bovine preimplantation blastocysts cultured in SOF+BSA. mRNA levels of the Igf2r gene and the Mash2 gene in in vitro-produced (IVP) and parthenogenetic expanded single blastocysts were analyzed by semi-quantitative RT-PCR (Wrenzycki C et al., 2001 Biol. Reprod. 65, 309–317). Genes expressed exclusively from the maternal allele (i.e. paternally methylated) should be represented by a higher relative abundance of transcriptional products in parthenogenetic embryos whereas paternally expressed genes (i.e. maternally methylated) should be correlated with a higher gene expression in IVP embryos carrying one paternal and one maternal allele. For determination of methylation patterns by bisulfite sequencing, sequences of several DNA fragments from the bovine Igf2 gene were identified in samples from bovine uterus and kidney. The primer pairs were generated from the ovine and bovine Igf2 sequences available in the Genebank database (accession number U00664/X53553). DNA fragments identified were from the 5′ untranslated region and the 3′ translated region of the bovine Igf2 gene. All fragments consist of a high number of CG dinucleotides, and computer analysis using the CpGwin program (Anbazhagan R et al., 2001 BioTechniques 30, 110–114) revealed CpG islands within these fragments. Relative abundances of transcriptional products were statistically analyzed using the SigmaStat 2.0 (Jandel Scientific, San Rafael, CA, USA) software package. After testing for normality, an ANOVA followed by multiple pairwise comparisons using the Tukey test was employed. Results from the semi-quantitative RT-PCR analyses revealed no difference (P&gt;0.05) in gene expression pattern of the Igf2r gene, suggesting that the Igf2r gene is biallelically expressed during bovine preimplantation development. In contrast, there was a significant difference (P&lt;0.05) in the relative abundance of mRNA of the Mash2 gene, with a lower relative abundance of transcriptional products in parthenogenetic expanded blastocysts. Thus, in cattle as reported in mice (Guillemot F et al., 1995 Nat. Genet. 9, 235–242), the paternal allele of the Mash2 gene seems to participate in the expression of the gene prior to implantation.

Umkehrplastik im operativen Behandlungsplan der prim�r malignen Knochentumoren

Long-term survival of patients with a malignant bone tumor increased with a combined therapeutic approach using chemotherapy and possibly radiation therapy. Today up to 80% of patients with an osteosarcoma or Ewing's sarcoma survive. Therefore, it is important that the functional outcome and the quality of life are good after resection of the tumor. Before the era of endoprosthetic devices, rotationplasty, which was introduced in 1974 by Salzer for surgery of malignant bone tumors and modified by Winkelmann, protected many patients from an amputation. Although many authors favor limb-saving procedures today, rotationplasty obtained excellent functional and psychosocial results. Rotationplasty can be recommended in tumors with a large soft tissue component, in tumors located in the proximal femur and proximal tibia, and in children under 10 years of age. Furthermore, rotationplasty can be used in patients in whom a limb-salvage procedure failed because of infection or repeated changes of the endoprosthesis.

[Options for surgical treatment of malignant bone tumors]

Beside the susceptibility to a (neo-) adjuvant therapy, the surgical margin is the most important prognostic factor in the treatment of primary malignant bone tumors. If adjuvant therapy is not possible, the outcome of the disease depends on the selected surgical treatment. Limb salvage has proven to be a safe procedure for local tumor control and provides good functional results. The surgeon has to consider the best surgical option depending on the site and size of the tumor but also depending on the patient's age and the overall prognosis. Surgical techniques and possible complications of the most common procedures in tumor surgery are described.

Reconstruction of the proximal humerus after wide resection of tumours

In 45 patients we assessed the functional results and complications for three different reconstructive procedures after resection of primary tumors of the proximal humerus. An osteoarticular allograft was used in 11, a clavicula pro humero operation in 15 and a tumour prosthesis in 19. The glenoid was resected with the proximal humerus in 25 patients. The axillary nerve was resected in 42 patients.

The complication rate was lowest after reconstruction with a tumour prosthesis. The clavicula pro humero operation resulted in the most revisions. Cumulative survival rates for all the reconstructive procedures were similar.

At follow-up at two years the functional results for the three reconstructive procedures were the same with a mean functional rating of 79% (Musculoskeletal Tumor Society). Excision of the glenoid had no influence on the functional result.

Our findings indicate that the use of a tumour prosthesis is the most reliable limb-salvage procedure for the proximal humerus. The clavicula pro humero is an appropriate procedure if a prosthesis cannot be used.

Reconstruction of the proximal humerus after wide resection of tumours

In 45 patients we assessed the functional results and complications for three different reconstructive procedures after resection of primary tumours of the proximal humerus. An osteoarticular allograft was used in 11, a clavicula pro humero operation in 15 and a tumour prosthesis in 19. The glenoid was resected with the proximal humerus in 25 patients. The axillary nerve was resected in 42 patients. The complication rate was lowest after reconstruction with a tumour prosthesis. The clavicula pro humero operation resulted in the most revisions. Cumulative survival rates for all the reconstructive procedures were similar. At follow-up at two years the functional results for the three reconstructive procedures were the same with a mean functional rating of 79% (Musculoskeletal Tumor Society). Excision of the glenoid had no influence on the functional result. Our findings indicate that the use of a tumour prosthesis is the most reliable limb-salvage procedure for the proximal humerus. The clavicula pro humero is an appropriate procedure if a prosthesis cannot be used.

Stump lengthening after hip disarticulation using a modular endoprosthesis in 5 patients

To reduce the disability after hip disarticulation, we developed a special surgical procedure in patients having a proximal femoral tumor with a large tumor involving the sciatic nerve or neoplasms involving the tibia and femur. The hip was disarticulated, but we preserved a musculocutaneous flap. A modular endoprosthesis was then placed in the acetabulum or, in case of an extraarticular resection of the hip joint, it was placed in the iliac bone. A trevira tube was used for reconstruction of the joint capsule and fixation of soft tissues. We performed this procedure in 5 patients who had a good functional outcome.

Mechanical quality of tissue engineered cartilage: results after 6 and 12 weeks in vivo

Traumatic events are a primary cause for local lesions of articular cartilage. If treated early, restoration of the initial joint geometry and integrity may be achieved. In large defects, sufficient material is not available to bridge the affected area. Heterologeous transplantation is not well accepted due to the risk of infection and immune response. Alternatives are cartilage-like structures, which may be cultured in vitro and transplanted into the defect site. Critical to the success of these new tissues are their mechanical properties. Goals of this study were to generate a hyaline-like cartilage structure, to evaluate its performance in vivo and to verify that its cellular and material properties meet those of native cartilage. Hyaline-like cartilage specimens were generated in vitro and implanted in the backs of nude mice. Specimens were explanted after 6 and 12 weeks, mechanically tested using an indentation test and histologically examined. In mechanical testing, stiffness and failure load significantly increased between weeks 6 and 12. At 12 weeks, mechanical properties of the hyaline-like cartilage were comparable to those of native nasal septal cartilage. Compared to native articular cartilage, the engineered tissue achieved up to 30-50% in strength and mechanical stiffness. In histological examination, specimens showed neocartilage formation. The mechanical testing procedure proved to be sufficiently sensitive to identify differences in properties between cartilage specimens of different origin and at different stages of healing. As an adjunct to histological analysis, mechanical testing may be a valuable tool for judging the utility of engineered cartilage prior to a broad clinical usage.

Examination of cognitive variables relevant to sunscreen use

The present study is an examination of the underlying psychological variables relevant to a sun-damage preventive behavior, sunscreen use. The focus of the research was to examine cognitive predictors of sunscreen use, utilizing a decision theoretic framework. Two hundred thirty subjects were recruited from psychology classes and administered questionnaires assessing sunscreen behavioral tendencies, attitudes toward sunscreen use, and internal- and external-based cognitions relevant toward sunscreen use. In contrast to previous work that had examined only one or two of these predictor variables in isolation, the present study evaluated the relative impact of these variables on sunscreen use tendencies. The findings revealed evidence of a multivariate model (using structural equation modeling; LISREL VIII) relating perceived need for, perceived efficacy of, perceived consequences of, and social normative influences on sunscreen use. The findings are discussed with respect to improving the effectiveness of short-term education efforts to increase sunscreen use.

Examination of cognitive variables relevant to sunbathing

This study examined cognitions relevant to sunbathing decision-making in college-aged subjects. Using Jaccard's (1981) theory of alternative behavior as a guiding model, 263 subjects were recruited from psychology classes and administered questionnaires assessing their sunbathing behavioural tendencies, attitudes toward sunbathing, attitudes toward reasonable behavioral alternatives to sunbathing, and cognitive variables underlying these attitudinal variables. The fits of models predicting sunbathing attitudes and sunbathing behavioural tendencies (evaluated using covariate structural equations modeling techniques; LIS-REL VIII) were good for all models tested. In contrast to previous work, the results of this study support the notion that young people will make their decisions regarding sunbathing based on the behavioral alternatives available to them (i.e., generally the one that they prefer most). Furthermore, the multivariate approach used clearly delineates the specific cognitive beliefs and orientations that might be targeted to change these attitudes. The relevance of these findings to skin cancer prevention interventions is discussed.