Monoflange custom-made partial pelvis replacements offer a viable solution in extensive Paprosky III defects.

Aims: Custom-made partial pelvis replacements (PPRs) are increasingly used in the reconstruction of large acetabular defects and have mainly been designed using a triflange approach, requiring extensive soft-tissue dissection. The monoflange design, where primary intramedullary fixation within the ilium combined with a monoflange for rotational stability, was anticipated to overcome this obstacle. The aim of this study was to evaluate the design with regard to functional outcome, complications, and acetabular reconstruction. Methods: Between 2014 and 2023, 79 patients with a mean follow-up of 33 months (SD 22; 9 to 103) were included. Functional outcome was measured using the Harris Hip Score and EuroQol five-dimension questionnaire (EQ-5D). PPR revisions were defined as an endpoint, and subgroups were analyzed to determine risk factors. Results: Implantation was possible in all cases with a 2D centre of rotation deviation of 10 mm (SD 5.8; 1 to 29). PPR revision was necessary in eight (10%) patients. HHS increased significantly from 33 to 72 postoperatively, with a mean increase of 39 points (p < 0.001). Postoperative EQ-5D score was 0.7 (SD 0.3; -0.3 to 1). Risk factor analysis showed significant revision rates for septic indications (p ≤ 0.001) as well as femoral defect size (p = 0.001). Conclusion: Since large acetabular defects are being treated surgically more often, custom-made PPR should be integrated as an option in treatment algorithms. Monoflange PPR, with primary iliac fixation, offers a viable treatment option for Paprosky III defects with promising functional results, while requiring less soft-tissue exposure and allowing immediate full weightbearing.

The Modified Harrington Procedure for Metastatic Peri-Acetabular Bone Lesion Using a Novel Highly Porous Titanium Revision Shell with Long Lever Arm Screw.

Background and Objectives: Peri-acetabular metastases often lead to significant pain and functional impairment. Surgical interventions, including the Harrington procedure, aim to address these challenges. This study evaluates a modified Harrington procedure using the MUTARS® PRS® (Pelvic Revision Shell) with an 8 mm fixation screw for severe acetabular defects resulting from metastatic lesions. Materials and Methods: Retrospective analysis of 12 patients treated between January 2020 and December 2023 was conducted. The procedure involved using the novel MUTARS® PRS® with an 8 mm in diameter dome screw (length 70-100 mm). Outcome measures included implant positioning changes, complication rates, functional outcomes, implant longevity, and patient survival. Radiological assessments were performed postoperatively, with follow-ups at 3, 6, 12 months, and annually thereafter. Results: Average follow-up was 15 ± 11 months, with 67% patient survival at 1 year and 44% at 2 years. Implant survivorship remained 100%. Harris Hip Score improved significantly from 37 ± 22 preoperatively to 75 ± 15 at the last follow-up. No revisions involving implant components were reported. Complications occurred in 5 of 12 patients. Overall, PRS® demonstrates effective osseous ingrowth, high primary stability, immediate full weight-bearing, and low complication rates. Conclusions: PRS® integrates facilitating osseous ingrowth for preferable long-term outcomes, while efficiently transmitting the weight-bearing load to the intact aspect of the pelvis using a long 8 mm lever screw, enhancing the primary stability of the construct. It proves to be an effective and reproducible technique for managing destructive metastatic lesions of the acetabulum and peri-acetabular region, even in irradiated bone.

Mouldable Collagen-Tricalciumphosphate Is a Safe Carrier for Local Antibiotics-Short-Term Results in Revision Hip Arthroplasty.

BACKGROUND: Improving local antibiotic delivery is a promising approach to improve infection control and potentially shorten systemic treatment in periprosthetic joint infection (PJI). This study investigates the use of an antibiotic-loaded, mouldable collagen-tricalciumphosphate composite in treatment of hip PJI. METHODS: 124 application cases in 79 patients were included from a referral centre; systemic adverse infects, local complications, and infection control were analysed. RESULTS: In most cases, either vancomycin or meropenem were used. Pathogens were previously known in 82 (66%) cases with polymicrobial infection in 20 (25%) patients. There were no cases of hypercalcaemia. Acute kidney injure was present in 14 (11%) cases. Chronic kidney failure persisted in two cases. During a mean follow-up of 12 (SD 9.3; range 3-35) months, implant survival was achieved in 73 (92%) patients; revision due to PJI was performed in 19 cases. CONCLUSION: Mouldable collagen-tricalciumphosphate composite bone substitute as a local antibiotic carrier in revision hip arthroplasty appears to be a valid option for local antibiotic delivery without systemic complications. Implant survival of 92% supports the hypothesis that local antibiotic therapy is an important component in the treatment of PJI.

The Megaendoprosthesis in Revision Arthroplasty - a Cost-revenue Analysis in the aG-DRG System. / Die Megaendoprothese im Revisionsfall ­ eine Kosten-Erlös-Analyse im 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]. / Individuelle Beckenteilersatz-Implantate: 3-D-Planung und Versorgungskonzepte.

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.

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.

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.

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.

The primary stability of pelvic reconstruction after partial supraacetabular pelvic resection due to malignant tumours of the human pelvis: a biomechanical in vitro study.

BACKGROUND: Up until now, reconstructions after partial supraacetabular pelvic resection have been done with the use of megaprostheses or allo-/autografs, including screws. The literature states complications in up to 100%. Therefore, the university hospital of Muenster has successfully established a reconstruction using poly-axial screws and titanium rods in combination with a Palacos(®) shroud. The aim of this study was to gather data on primary stability of five different types of reconstruction. METHODS: Using a biomechanical model Load (N), displacement (mm) and stiffness (N/mm) were recorded in load cycles from 100N up to 1050N. FINDINGS: The data shows that reconstructions with poly-axial screws, titanium rods and Palacos(®) can bear a load of up to 1050N without structural damages. The same is valid with an additional bone graft and for a full metal prosthesis. Referring to reconstructions with just bone graft or without graft and Palacos(®) the load-bearing capacity is significantly worse. Additionally, structural damages were recorded in those reconstructions from 700N onwards. INTERPRETATION: Due to the biomechanical results and the save and easy handling, reconstructions with poly-axial screws, titanium rods and Palacos(®) (and, if necessary, bone graft) can be recommended achieving high primary stability for pelvic ring reconstruction after partial supraacetabular pelvic resection.

Hip transposition as a limb salvage procedure following the resection of periacetabular tumors.

BACKGROUND AND OBJECTIVES: One of the most difficult problems in tumor surgery is the treatment of pelvic tumors, particularly those in the periacetabular region. This retrospective study serves to analyze clinical and functional outcome of the new surgical technique of hip transposition. PATIENTS AND METHODS: Sixty-two patients were analyzed (chondrosarcoma 15, Ewing's sarcoma or PNET 26, osteosarcoma 14, synovial cell sarcoma 2, others 5) and clinical, oncological, and functional outcome were evaluated. RESULTS: The surgical procedure focused on hip transpositions Type I (n = 9), Type IIa using the MUTARS attachment tube (n = 36), and Type IIb using the MUTARS attachment tube with a proximal femur endoprosthesis and bipolar cup (n = 17). In 53 patients (85.5%), wide margins were achieved. The 1- and 5-year overall survival rates were 96.4% and 80.5%, respectively. The 5-year (10 years) overall survival was 82.1% (82.1%) for Ewing's sarcoma, 60.1% (40.6%) for osteosarcoma, and 92.3% (46.2%) for chondrosarcoma. Wound healing problems were observed in 14 cases, deep infection in 20 cases. The mean Musculoskeletal Tumor Society (MSTS) score was 62% (18.6 Pts ± 3.73). CONCLUSION: Hip transposition can be considered as an easy and safe surgical procedure to employ in order to achieve good functional outcome in periacetabular tumors.

Proximal fibula resection in the treatment of bone tumours.

BACKGROUND AND OBJECTIVES: We present a large study of patients with proximal fibula resection. Moreover we describe a new classification system for tumour resection of the proximal fibula independent of the tumour differentiation. METHODS: In 57 patients the functional and clinical outcomes were evaluated. The follow-up ranged between six months and 22.2 years (median 7.2 years). The indication for surgery was benign tumours in ten cases and malignant tumours in 47 cases. In 13 of 45 patients, where a resection of the lateral ligament complex was done, knee instability occurred. In 32 patients a resection of the peroneal nerve with resulting peroneal palsy was necessary. RESULTS: Patients with peroneal resection had significantly worse functional outcome than patients without peroneal resection. An ankle foot orthosis was tolerated well by these patients. Three of four patients with pathological tibia fracture had local radiation therapy. There was no higher risk of tibia fracture in patients with partial tibial resection. CONCLUSIONS: Resection of tumours in the proximal fibula can cause knee instability, peroneal palsy and in cases of local radiation therapy, a higher risk of delayed wound healing and fracture. Despite the risks of proximal fibula resection, good functional results can be achieved.

Reconstruction after wide resection of the entire distal fibula in malignant bone tumours.

In this study we present a series of patients (n = 11) with resection of the entire distal fibula in the case of sarcoma or metastasis. Moreover, we describe a new method to restore ankle stability with a tibiotalocalcaneal arthrodesis using a retrograde hindfoot nail (n = 4) in contrast to tibiotalar arthrodesis with screws (n = 5). The screw fixation failed in two patients due to osteopoenic bone. The crucial benefits of an arthrodesis with a retrograde nail are a stable arthrodesis, intramedullary stabilisation of the tibia and avoidance of extrinsic material in the wound area. An arthrodesis with a retrograde nail is a good alternative for reconstruction after a wide distal fibula resection. The additional arthrodesis of the subtalar joint was not associated with worse functional results in the MSTS and TESS scores.

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.

The Modular Universal Tumour And Revision System (MUTARS®) in endoprosthetic revision surgery.

The aim of this study was to present the clinical and functional results of revision surgery after failed hip endoprostheses using the Modular Universal Tumour And Revision System (MUTARS®). Functional results of the hip endoprostheses were recorded by applying the Harris hip score. The extent of the presurgical radiological bone defect was measured according to the classification system of the German orthopaedic association (DGOOC). Indications for revision surgery on 45 patients (21 female, 24 male) were aseptic loosening (19 patients), infection (16 patients), or periprosthetic fracture (Vancouver classification B2, B3 and C, in nine patients). Revision surgery was performed after 8.6 years on average (min. 0.6; max. 14.25 years). Large defects of the proximal femur (80% medial or lateral diaphysis; 20% meta-diaphysis according to DGOOC classification) were adequately reconstructed. The average follow-up was 38.6 months. Complications occurred in eight patients: one luxation, two aseptic loosenings, and five reinfections were diagnosed. The Harris hip score (presurgical 30; postsurgical 78) showed significant improvement after revision surgery. Regarding the extent of the patients' bone defects, good functional results were achieved. The comparatively low number of luxations and loosenings is due to the high modularity of the prosthesis with arbitrary antetorsion in the hip joint. However, high reinfection rates in mega-implants still constitute a problem and should be the subject of further studies.

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.

The primary stability of the hip transposition type IIb: a biomechanical in vitro study.

BACKGROUND: The hip transposition is firmly established in pelvic sarcoma surgery. However, the primary stability of the hip transposition has not been tested yet so that the mobilisation, respectively the immobilisation of the patient so far solely relied on the experience of the surgeon. The aim of this study was to test the primary stability reliably with the help of a model and to reveal possible differences in stability between currently used anchor systems (TwinFix 6.5 and MITEK SuperAnchor). METHODS: A biomechanical model of porcine sacra was developed to document the maximum load capacity (load to failure test) and the performance under cyclic load (100 N, 200 N, 350 N, 700 N, 1400 N, each with 1000 cycles), 28 sacra were tested in total. Macroscopic damages, displacement, yield load, stiffness and F(max) were recorded as well. FINDINGS: The load to failure test results showed a 3.9 times higher maximum load capacity for the TwinFix 6.5 anchor (1307 N) compared to the MITEK SuperAnchor (334N). The cyclical test revealed that nearly all MITEK SuperAnchors failed at a load of 350 N. In contrast, the TwinFix 6.5 anchors resisted 4000 cycles up to a load of 1400 N. INTERPRETATION: The TwinFix 6.5 anchor proved to be clearly superior to the MITEK SuperAnchor, resulting in the adjustment of the reconstruction technique. Therefore, the immobilisation period of a patient after a hip transposition type IIb could be shortened according to the results of the primary stability test.

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.

Hip transposition as a universal surgical procedure for periacetabular tumors of the pelvis.

Surgical treatment of pelvic tumors represents one of the most challenging problems in musculoskeletal oncology, especially in the periacetabular region. Because of the complex anatomy and demanding biomechanical situation, surgery leads to a considerable disability while all possible types of reconstruction are often associated with high complication rates. Nevertheless, it is known that wide resection of the tumor is one of the key points for long-term survival in sarcoma therapy. Therefore, hip transposition was established in our clinic as a universal tool for periacetabular tumors excelling in small foreign parts and resulting in acceptable complication rates with good functional outcome. The following article gives an overview of the technique and the indications of different types of hip transposition, which were developed from the first procedure, described and published by Winkelmann in 1988.

Rotationplasty in the elderly.

Purpose. Rotationplasty has proven its efficacy in the treatment of malignant bone tumors of the lower extremity in predominantly young patients. To our knowledge this procedure has not been reported in patients over 60 years before. Materials and Methods. 3 patients over 60 years with an A1-rotationplasty because of a sarcoma were included in this study. Complications and functional results were recorded. In one patient an electromyography was done. Results. Despite electromyography showing good adaptation of the muscles to the altered function, the functional results of these three patients were limited. two out of three patients needed a cane for walking distances over 200 meters. No secondary amputation was necessary. Discussion. Our study demonstrates that rotationplasty is an alternative to an above-knee amputation in older patients but with poorer functional results in comparison to younger patients. However, limb-salvage surgery should be preferred whenever possible.

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.