Aim

The aim of this study was to analyze our results using a modular endoprosthetic replacement system (MUTARS) for bone tumours of the proximal humerus.

Introduction: Following intralesional resection of giant cell tumour local recurrence happens in up to 40% depending on type of treatment. Common plain radiography or Magnetic resonance tomography (MRI) often has the problem not to discriminate between scar and recurrent tumour.

Materials and Methods: In 19 patients with giant cell tumour dynamic PET using F18-Fluordeoxyglucose (FDG) for estimation of FDG turnover was carried out. PET was performed before surgery and as follow up. In case of evidence in x-ray or MRI of recurrent giant cell tumour PET was performed again. results of histologic evaluation after reoperation then were compared to results of PET.

Results: All giant cell tumours showed a specific PET pattern with a very high standard uptake value (SUV) of 4.8 in median. In one case pulmonary metastases could be found. In follow up after surgery this value dropped to 0.3. Recurrence was suspected in the follow up in 5 patients by MRI or plain radiography. In all these patients PET could show an elevated SUV above 4.0. In these 5 patients surgery was performed and recurrence could be proven by histology. In one patient MRI was negative but PET showed a SUV of 5.2 indicating re-recurrent tumour which could be demonstrated by histology.

Conclusion: We conclude that PET is a very helpful tool not only in the first line diagnosis of giant cell tumour but also in diagnosis of metastatic disease and especially for detection of recurrent tumour.

Introduction: Periprosthetic infection remains a main complication in arthroplasty. In case of a possible infection the surgeon has to have a concept of treatment which can be individually adjusted.

Materials and Methods: To increase the success of implant retaining surgery VAC Instill therapy combining instillation of an antiseptic solution and VAC therapy was performed in 23 patients with periprosthetic hip infections. 19 patients had an early and 4 a late infection of the arthroplasty. Lavasept was used for irrigation.

Results: Definitive wound closure was possible in all patients following 2.1 VAC exchange operations in average. The follow up was 19 months in average. In five of the 23 patients (22%) there was recurrent infection which made the explantation of the implant necessary. In early infection the success rate was 84%, in late infection 50%.

Conclusion: VAC Instill therapy can be successfully used for salvage of infected endoprosthesis especially in case of early infection. The success rate seems to be higher than irrigation alone or suction drainage.

Following intralesional resection of giant cell tumour local recurrence happens in up to 40% depending on type of treatment. Common plain radiography or Magnetic resonance tomography (MRI) often has the problem not to discriminate between scar and recurrent tumour tissue in the cement-tissue border of lesions treated with cement packing. The value of Positron emission tomography (PET) for diagnosis of tumour and recurrence was investigated in these patients.

In 19 patients with giant cell tumour dynamic PET using F18-Fluordeoxyglucose for estimation of FDG turnover was carried out. PET was performed before surgery and as follow up. In all patients giant cell tumour was treated by curettage followed by burring and cement packing. Giant cell tumour was shown by histology in all patients.

All giant cell tumours showed a specific PET pattern with a very high standard uptake value (SUV) of 4.8 in median. In follow up after surgery this value dropped to 0.3. In one case also pulmonary metastasis could be demonstrated. Recurrence was suspected in the follow up in 5 patients by MRI or plain radiography. In all these patients PET could show an elevated SUV above 4.0. In these 5 patients surgery was performed and recurrence could be proven by histology. In one patient MRI showed signs of recurrence but PET showed a SUV of 1.3. In the revision surgery no tumour could be found. In one patient MRI was negative but PET showed a SUV of 5.2 indicating re-recurrent tumour which could be demonstrated by histology.

We conclude that PET is a very helpful tool not only in the first line diagnosis of giant cell tumour but also in diagnosis of metastatic disease and especially for detection of recurrent tumour.

Following resection of primary malignant bone tumours of the humerus, limb salvage can be performed by vascularized fibula graft for reconstruction of large segmental defects.

In 12 patients with malignant bone tumour of the proximal humerus, tumour was resected and the bone defect reconstructed by vascularized fibula graft. Median age of the patients was 23 years. Median follow up was 114 months.

In 10 patients humeral head had to be resected and was replaced by fibular transplant including head and shaft of the ipsilateral fibula. Humeral head could be left in place in 2 patients. Median length of transplant was 17.2 cm. Radiographic union could be seen after 8 months in median. In 7 patients partial necrosis of the fibular head occurred, in 4 patients fracture of the transplant happened following trauma. In these 4 cases revision surgery was required. Partial necrosis of the head of fibula had no significant influence on shoulder function. One patient died of disease, the others are disease free. Enneking Index was 61% in median at time of last follow up. At donor side 3 cases of transient peroneal palsy could be seen.

We conclude that vascularized fibula graft is a successful surgical procedure for upper limb salvage especially for preservation of joint function also in long term follow up.

Chondrosarcomas are hyaline cartilage-forming tumours which can be classified according to malignancy through histological grading. Grade I chondrosarcomas rarely metastasize whereas in grade III chondrosarcoma metastasis is observed in 71% of cases. There is, so far, no clear molecular marker allowing an objective classification of chondrosarcoma. The aim of this project was to identify such marker genes through the comparison of gene expression of chondrosarcoma and normal hyaline cartilage and through the correlation of expression profiles to histological grading.

The mRNA of 19 chondrosarcomas with different histological grades and of eight normal cartilage samples was analysed. Gene expression profiles were assessed on a customised cDNA array including 230 cartilage- and stem cell-relevant genes. Data were analysed by hierarchical clustering and significance analysis of microarrays. Results were confirmed by real-time RT-PCR.

Gene expression profiles clearly discriminated between normal and neoplastic cartilage. Between them, 73 differentially expressed genes were identified. The genes higher expressed in cartilage included several genes encoding matrix proteins. Among the genes higher expressed in chondrosarcoma, molecules involved in PTH and BMP signalling were found. Genes differentially expressed between tumours of different grade were identified. Among others, galectin 1 was significantly higher expressed in highly malignant tumours compared to grade I tumours. This correlation could be confirmed at protein level by immunohistological analysis.

The comparative analysis of normal cartilage and chondrosarcoma gene expression showed that there are important molecular differences between the matrix of normal and neoplastic cartilage. Our results furthermore confirm that genes implicated in the regulation of the growth plate were expressed in chondrosarcoma. Remarkably, we identified galectin 1 as a marker correlating to malignancy on the level of gene and protein expression. More extended studies on this functionally polyvalent molecule would be necessary to establish it as a marker for malignancy in chondrosarcoma.

The aim of the study was to compare mortalitiy and complication rate after operative treatment of pertrochanteric fractures with primary cemented arthroplasty, dynamic hip screw (DHS) or proximal femoral nail (PFN).

283 patients, which were treated betwen 1992 and 2005 for pertrochanteric femoral fractures, except pathologic fractures and a minimum age of sixty years were included. 132 of these 283 patients were treated by primary arthroplasty.

Up to the end of 1999 all unstable fractures were treated by primary total hip replacement. In the year 2000 the PFN was introduced and only patients with severe osteoarthritis and osteoporosis received primary arthroplasty. I possible, more stable fractures were treated with a DHS.

One year mortality was chosen as main indicator as it depends on the surgical trauma as well as the rapid return to preinjury activity and further complications. A one year period was chosen as the mortality ratio approaches that of an age matched reference population after this interval. Influencing cofactors were eliminated by stepwise logistic regression analysis.

It was shown that restoration of the preoperative ambulatory level correlated with survival rate after one year. As elderly patients are often unable to cooperate with partial weight bearing, the primary stability of the device is crucial to allow early mobilisation

Mortality was significantly influenced by age, gender and comorbidities but not by fracture classification. One-year mortality was significantly higher for primary total hip replacement (34.2 %) than for internal fixation (DHS: 18.4 %; PFN 21.4 %) and hemiarthroplasty (13.3 %). Since the PFN and hemiarthroplasty were introduced the over all mortality was reduced from 29 % to 18 %.

Conclusion: For stable fractures a Dynamic Hip Screw (DHS) and for unstable fractures a short proximal femoral nail (PFN) can be recommended. Primary cemented hemiarthroplasty is a viable option for treatment of intertrochanteric fractures if osteoporosis prevents from full weight bearing or if osteoarthritis makes further operations likely. Primary total hip replacement should be avoided, due to the fact that dislocation and mortality were significantly higher than in the other groups.