Introduction

Coronal malalignment and leg length discrepancies (LLD) are frequently associated. Temporary hemiepiphysiodesis (tHED) is commonly employed for the correction of limb malalignment in skeletally immature patients. For treatment of LLD greater than 2 cm, lengthening with intramedullary legnthening nails is a safe and reliable technique. However, the combined application of these approaches in skeletally immature patients has not yet been investigated.

Aims

Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model.

Aims

The microbiological detection of microorganisms plays a crucial role in the diagnosis as well as in the targeted systemic and local antibiotic therapy of periprosthetic infections (PJI). Despite extensive efforts to improve the sensitivity of current culture methods, the rate of culture-negative infections is approximately 10–20% of all PJI. This study investigates an preanalytical algorithm (culture collection and direct processing in the OR) to potentially increasing culture yield in patients with PJI.

Aim

The time to onset of symptoms after fracture fixation is still commonly used to classify fracture-related infections (FRI). Early infections (<2 weeks) can often be treated with debridement, systemic antibiotics, irrigation, and implant preservation (DAIR). Late infections (>10 weeks) typically require implant removal as mature, antibiotic-tolerant biofilms have formed. However, the recommendations for delayed infections (2–10 weeks) are not clearly defined. Here, infection healing and bone healing in early and delayed FRI is investigated in a rabbit model with a standardized DAIR procedure.

Aim

A novel anti-infective biopolymer implant coating was developed to prevent bacterial biofilm formation and allow on-demand burst release of anti-infective silver (Ag) into the surrounding of the implant at any time after surgery via focused high-energy extracorporeal shock waves (fhESW).

Aim

Repeat revision surgery of total hip or knee replacement may lead to massive bone loss of the femur. If these defects exceed a critical amount a stable fixation of a proximal or distal femur replacement may not be possible. In these extraordinary cases a total femur replacement (TFR) may be used as an option for limb salvage. In this retrospective study we examined complications, revision free survival (RFS), amputation free survival (AFS) and risk factors for decreased RFS and AFS following a TRF in cases of revision arthroplasty with a special focus on periprosthetic joint infection (PJI).

Aim

Periprosthetic joint infection (PJI) is a devastating complication in revision total hip arthroplasty (THA). As preoperative diagnosis can be difficult, some patients who undergo planned aseptic revision surgery might have positive intraoperative cultures and later be classified as infected. In this retrospective study we analyzed the influence of intraoperative positive cultures and possible underlying risk factors in patients undergoing planned aseptic THA revision.

Aim

Due to medical and organizational factors, it occurs in everyday practice that spacers are left in place longer than originally planned during a two-stage prosthesis exchange in the case of prosthetic joint infections. Patients are severely restricted in their mobility and, after initial antibiotic administration, the spacer itself only acts as a foreign body. The aim of this study is to analyze whether the duration of the spacer in situ has an influence on the long-term success of treatment and mortality.

Aims

Periprosthetic fungal infections are rare and account for 1–2% of all periprosthetic joint infections (PJI). This study aims at presenting treatment details, clinical and microbiological results in a large single centre cohort.

Aim

Diagnosis and isolation of a causative organism is imperative for successful treatment of periprosthetic joint infections (PJI). While there are several diagnostic algorithms using microbiology, serum and synovial markers, the preoperative diagnosis of a low-grade infection remains a challenge, particularly in patients with unsuccessful aspiration. An incisional biopsy may be used in these cases as additional diagnostic tool. In this retrospective study we evaluated microbiological findings, sensitivity, and specificity of open synovial biopsies in cases of inconclusive preoperative diagnostics.

Aims

Temporary epiphysiodesis (ED) is commonly applied in children and adolescents to treat leg length discrepancies (LLDs) and tall stature. Traditional Blount staples or modern two-hole plates are used in clinical practice. However, they require accurate planning, precise surgical techniques, and attentive follow-up to achieve the desired outcome without complications. This study reports the results of ED using a novel rigid staple (RigidTack) incorporating safety, as well as technical and procedural success according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework.

Aims

This study aims to enhance understanding of clinical and radiological consequences and involved mechanisms that led to corrosion of the Precice Stryde (Stryde) intramedullary lengthening nail in the post market surveillance era of the device. Between 2018 and 2021 more than 2,000 Stryde nails have been implanted worldwide. However, the outcome of treatment with the Stryde system is insufficiently reported.

Aim

We present the greatest 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 dignity.

Introduction: It is noted that infections make up the most feared complications of prostheses’ surgery in orthopaedic implants after resection of primary or secondary cancer of limb bones. The causes must be attributed to the entity of the skeletal resection and of surrounding soft tissues sacrifice, to the duration of surgery and to the pre-operative cycle of chemotherapy or radiotherapy. Infections of prostheses in oncology are caused mainly by bacteria present either in isolated strains or in poly-microbic associations, and most recently fungus infections have begun to be found, in immunodepressed patients. Candidemia makes up an important cause of systemic infections in immuno-compromised oncological patients, who received high doses of chemotherapy; moreover candidemia represents a high risk of hospital sepsis. It is noted that the behaviour of the Candida is interpreted through the production of a biofilm and then the inhibition of the production of the biofilm itself is translated into a potential antifungal effect. From the analysis of the literature a protective role carried out by the silver coating of the tumoural prostheses towards the bacterial infections is deduced. It is noted, in fact, the antimicrobiotic effect of medical devices coated in silver; in particular in studies conducted in animals favourable results were demonstrated on bacterial adherence of titanium devices coated with silver. The aim of the study was to evaluate in vitro the inhibition of the production of biofilm by different strains of Candida in the presence of titanium and titanium coated with silver.

Materials and Methods: Six strains of Candida were analyzed: 2 strains of C. albicans, 2 of C. tropicalis and 2 of C. parapsilosis. The fungal strains were stratified on discs of pure titanium, a material in which implants of tumoural prostheses are made, and furthermore on discs of titanium coated in silver, and the ability of the fungus to produce protective biofilm on different substratum was evaluated. All of the studies were conducted 3 times. The adherence to the biofilm was measured by semi-quantitative, colormetric and spettrophotometric methods according to standardized protocols.

Results: The spettrophotometric analysis demonstrated a statistically significant reduction of the production of biofilm by fungus strains that came in contact with titanium coated in silver compared to pure titanium in all of the strains that were examined, attested by the fact that the silver creates a micro-environment unfavourable for fungus growth.

Conclusion: The analysis of the results demonstrated that the Silver coating of the oncological prosthesis made an unfavourable micro-environment not only for bacteria, as has already been widely established, but also for fungus. For this reason we maintain that this coating constitutes a valid opportunity in oncological resections for those patients who, being treated with chemotherapy, radiotherapy and to long hospitalitations present an elevated risk of fungal infection in oncological resections. From the studies we conducted it appeared how fundamental the use of silver in tumoural prosthesis is in order to prevent contamination by fungal strains and how this use must be taken more and more into consideration to improve life expectancy of a particular and sensitive category of patients, especially oncological.

Early and late infections are the most uneventfull complications after tumor resection and implantation of a maegaendoprosthesis. Therefore, silver-coating was introduced by our department years ago with successful reduction in infection rates. After promising results in animal and Phase exclusion of side effects in our Phase I trial, we would like to share our knowledge about latest research, especially the actual results of the Phase II study. We included the results off all implanted silver-coated Megaendoprosthesis since introduction in our department. Implantation had to be more than 12 months ago to guarantee a acceptable minimum follow up for calculation of the infection rate. Actually our infection rate lies at 3,1% (N=131) in the prevention group (no previous infection in medical history) and at 19% (N=36) in our “Highest-Risk” and previous infection group. Still no side-effects could be noticed. In one case we examined retrieved samples of three silver-coated Megaendoprosthesis. Macroscopically a leopard shaped figures could be noticed on the silver-coated surface in shiny and dark areas after being implanted in an infected region. Electron microscopy pictures show still intact surface and remaining silver with dark staining. Biofilm formation coulod not be noticed, though some few dead single bacteria could be found without any signs of proliferation or matrix production after adhesion. Signs of biofilm couldn’t be seen anywhere. Despite the discoloration silver is still intact in these areas without any loss of antibacterial properties. Blisterings or even flaking off the silver coating cannot be noticed. The thickness of the silver was not thinned in a significant way leading to a breakdown after a few years.

Up to these days we have no experience in covering the whole prosthesis including the stem in human beings. Concerning osteointegration of silver-coated stems, our animal trial could not prove their effectiveness in comparison to titanium. Pull-out tests showed high significant discrepancies in osteointegration between titanium and silver coated stems in a dog model after a period of 12 months after implantation.

Summarizing we recommend silver as a safe adjuvant therapy in patients undergoing endoprosthetic reconstruction after tumor resection. Intramedullary use of silver can be done only in experimental cases and needs further changes in the technical design of the coating.

Although the recurrence rate of giant cell tumors of bone (GCTB) is relatively high exact data on treatment options for the recurrent cases is lacking. The possible surgical procedures range from repeated intralesional curettage to wide resection.

214 patients with histologically certified GCTB have been treated at the authors department from 1980 to 2007. 67 patients with at least one local recurrence were included in this study. The mean follow-up was 77.3 months. The data was evaluated according the re-recurrence rate with regard to the surgical procedure for the recurrence.

The mean time until the first local recurrence was 22.0 months; the mean number of recurrences per patient was 1.4. The recurrence occurred in 69.7 % (46 out of 66 patients) within the first two years. If after intralesional procedures (curettage or intralesional resection) no adjunct was used the re-recurrence rate was 58.8 % (10 out of 17 patients) and decreased to 21.7 % (5 out of 23 patients) if a combination of all adjuncts (PMMA + burring) was used. The likelihood of re-recurrence was reduced by the factor 5.508 which was clearly significant (p = 0.016). In case of wide resection no re-recurrence occurred. Seven patients (10.5 %) developed pulmonary metastases. Fourteen patients (20.9 %) finally received an endoprosthesis; 12 due to tumor recurrence, 2 due to secondary arthritis.

Recurrent GCTB can be treated by further curettage with additional burring and cementing with an acceptable re-recurrence rate of 21.7 %. The rate of patients finally needing an endoprosthesis is 20.9 %. Due to the high rate of pulmonary metastases recurrent GCTB may be considered as a severe disease.

Megaendoprotheses are widely used in the reconstruction of large bone defects in orthopaedic tumour surgery. The major complications (up to 36%) are periprosthetic infections. Persisting periprosthetic infections lead to secondary amputation up to 37% of the cases. One underestimated reason for persisting infections are subpopulations of S. aureus called “small colony variants” (SCVs). Aim of this study was to evaluate that silver ions might prevent or cure a periprosthetic infection caused by SCVs.

For testing the antimicrobial activity of silver-coated titanium we used a technique introduced by Bechert et al. Therefore an adhesion and proliferation assay was performed with clinical isolates of S. aureus SCV (A22616/3). We tested the adhesion and proliferation properties of S aureus SCV on stainless steel (steel), Cobalt-Chrome-Molybdenum-alloy (CoCrMo), Titan-Aluminium-Vanadium-alloy (TiAlVa) and silver-coated Titan-Aluminium-Vanadium-alloy (scTiAlVa).

Adhesion of S. aureus SCV is significantly reduced on scTiAlVa vs. steel (p> 0001). We could also demonstrate that the proliferation rate of scTiAlVa vs. all tested materials is significant (p> 0001) lower.

We concluded that silver-coating has an effective antimicrobial activity against S. aureus SCVs. Thus silver-coated megaendoprostheses are a good prophylaxis against persisting infections caused by S. aureus SCVs.

Several studies report a diminished BMD as a consequence of childhood cancer treatment. The aim of this study was to investigate the effects of an exercise intervention on BMD during treatment, since limited mobility is characteristic for cancer therapy and is a major determinant for bone loss.

We analysed DXA scans (Lunar Prodigy, GE Healthcare) of 53 patients (range 8 to 21 years at time of diagnosis) perioperatively (n=49), six (n=38) and twelve months (n=18) after surgery. Scans were performed for the established sites of the lumbar spine and both femora, as well as experimentally for both calcanei. Areal BMD was corrected to obtain volumetric BMD using the model of Kröger.

For both groups, areal and calculated volumetric BMD values were similar at the lumbar spine at time of surgery, as were the differences between affected and not affected femur and calcaneus. The six and twelve months postoperative measurements revealed higher volumetric and areal BMD at the lumbar spine for the intervention group, although significant differences were only found for volumetric BMD values six months postoperatively.

Furthermore, a comparison of both groups showed that the loss in bone density of the affected lower extremity was less pronounced for the intervention group: differences between affected and not affected femur were 9% to 73% higher in the femur and 20% to 29% higher in the calcaneus for the control group.

Previous reports dealing with diminished BMD in pediatric cancer patients were confirmed in this study. However, differences found in BMD between both groups indicate that an exercise intervention during treatment, consisting primarily of strength and endurance training, may inhibit bone loss in pediatric sarcoma patients. Furthermore, the calcaneal site may be an alternative when the determination of femur BMD is not feasible.

A revision of a first generation KMFTR prosthesis due to stem breakage is a problem oncologic surgeons are regularly faced with. We designed an adapter which allows us to connect new MUTARS components to the original KMFTR devices. Thus it is possible to bypass an exchange of the whole prosthesis.

We used this adapter in 10 patients. Time of revision was in average 16.6 years after primary implantation of the KMFTR prostheses. Reasons for revision were femoral stem breakage (n = 5), breakage of the tibial component (n = 3) and periprosthetic fracture (n = 2, one femoral, one tibial).

The femoral stem (3 cases) and the tibial stem (2 cases) as well as the tibial plateau and body (2 cases) could be replaced by MUTARS parts and conjoined with the remaining KMFTR devices. Three cases were converted to MUTARS total femur.

Postoperative complications were one aseptic loosening and one cone-dislocation. Pre-incidence function was restored in all cases. The average Musculoskeletal-Tumour-Society-Score was 82.9% of normal function.

The results show that the new adapter facilitates to restore pre-incidental extremity function by performing a relatively modest revision.

Infections are the most uneventfull complications after tumor resection and implantation of a maegaendopros-thesis.Silver-coating of megaendoprosthesis has become a regular procedure in our department since last year in tumor cases. Especially in revision cases with high risk of infection they play a major role in preventing adhesion of bacteria. The successful reduction in infection rates show the effectiveness of the coating but still leave the question “how much coating do we need?” and “how much coating can be tolerated.

Latest research concentrated on the coating of the stems, since they can still be the source of the infection if everything else is coated by silver already.

Summarised so far, our experience in a rabbit model, a phase I Trial in humans and prelimnary results in Phase II Trials in humans showed no toxic side effects.

Driven so far it seems to be sensible to extent the silver coating. So far, the coating is limited to all areas without joint movement or bone contact. An Animal trial was performed anylising the osteointegrative properties of an silver-coated stem versus an regular Titanium stem in 17 dogs. After 12 months of regular X-Ray Analysis a Pull-out test and a concentration analysis has been done.

Results showed high significantly (p< 0.001) an osteointegration in 8 out of 8 titanium stems with an average pull-out force of 3764 Newton (Range 1755– 5967 Newton). Silver-coated stems showed no signs of Osteointegration in all 9 out of 9 femurs. The average pull-out force was 21 Newton (Range 0– 186 Newton). A cemented control could resist a pull out force of 350 Newton. Analysis of the silver concentration directly in the first millimeter of the bone-implant interface and the second millimeter showed highly elevated silver levels.

The silver concentration in the bone-implant interface at Titanium stems ranged from 0.3 to 3502 parts per Billion (ng/g) compared to silver-coated stems ranging from 303 to 2.418.800 ppb parts per Billion (ng/g).

Discussion: Sharing the histologic picture and reactions of the osteoblasts to the silver-coating there are several possible reasons for failed osteointegration. We want o discuss wether these has to be considered as a toxic response or just an adverse reaction.

In summary, surgeons have to decide in the future how much silver they need in each individual case concerning intramedullary infection prophylaxis. The balance between loosening or infection should be based on long term expectations, taking into account that even after successful resection of a tumor an ongoning infection can lead to loosening of a limb or even life. Apart from intramedullary use, we recommend silver as a safe adjuvant therapy in all suited patients undergoing endoprosthetic reconstruction after tumor resection.