Aims. The aim of this study was to investigate the feasibility of application of a 3D-printed megaprosthesis with hemiarthroplasty design for defects of the distal humerus or proximal ulna following tumour resection. Methods. From June 2018 to January 2020, 13 patients with aggressive or malignant tumours involving the distal humerus (n = 8) or proximal ulna (n = 5) were treated by en bloc resection and reconstruction with a 3D-printed megaprosthesis with hemiarthroplasty, designed in our centre. In this paper, we summarize the baseline and operative data, oncological outcome, complication profiles, and functional status of these patients. Results. Preparation of the prosthesis was a mean of 8.0 days (SD 1.5), during which time no patients experienced tumour progression. The mean operating time and intraoperative blood loss were 158.1 minutes (SD 67.6) and 176.9 ml (SD 187.8), respectively. All of the prostheses were implanted successfully. During a mean follow-up of 25.7 months (SD 7.8), no patients died, but four had complications (two superficial wound problems, one temporary palsy of radial nerve, and one dislocation). No aseptic loosening, structural failure, infection, heterotopic ossification, or degenerative arthritis was seen in this study. The mean flexion of the elbow was 119.6° (SD 15.9°) and the mean extension lag was 11.9° (SD 13.8°). The mean Musculoskeletal Tumor Society 93 score and Mayo Elbow Performance Score were 28.4 (SD 0.9) and 97.7 (SD 4.4), respectively. Conclusion. The custom-made, 3D-printed megaprosthesis with hemiarthroplasty is a feasible option for functional reconstruction after resection of a tumour in the distal humerus or proximal ulna. Cite this article: Bone Joint J 2022;104-B(6):747–757

The February 2024 Research Roundup. 360. looks at: If you use a surgical helmet, you should seal your gown-glove interface; The use of iodophor-impregnated drapes in patients with iodine-related allergies: a case series and review of the literature; Location of the ovaries in children and efficacy of gonadal shielding in hip and pelvis radiography; Prehospital tranexamic acid administration does not improve outcomes in severe trauma patients; Silver-coated distal femur megaprosthesis in chronic infections with severe bone loss: a multicentre case series

Aims

The proximal tibia (PT) is the anatomical site most frequently affected by primary bone tumours after the distal femur. Reconstruction of the PT remains challenging because of the poor soft-tissue cover and the need to reconstruct the extensor mechanism. Reconstructive techniques include implantation of massive endoprosthesis (megaprosthesis), osteoarticular allografts (OAs), or allograft-prosthesis composites (APCs).

To analyse bone stresses in humerus-megaprosthesis construct in response to axial loading under varying implant lengths in proximal humeral replacement following tumour excision. CT scans of 10 cadaveric humeri were processed in 3D Slicer to obtain three-dimensional (3D) models of the cortical and cancellous bone. Megaprostheses of varying body lengths (L) were modelled in FreeCAD to obtain the 3D geometry. Four FE models: group A consisting of intact bone; groups B (L=40mm), C (L=100mm) and D (L=120mm) comprising of humerus-megaprosthesis constructs were created. Isotropic linear elastic behaviour was assigned for all materials. A tensile load of 200N was applied to the elbow joint surface with the glenohumeral joint fixed with fully bonded contact interfaces. Static analysis was performed in Abaqus. The bone was divided at every 5% bone length beginning distally. Statistical analysis was performed on maximum von Mises stresses in cortical and cancellous bone across each slice using one-way ANOVA (0-45% bone length) and paired t-tests (45-70% bone length). To quantify extent of stress shielding, average percentage change in stress from intact bone was also computed. Maximum stress was seen to occur distally and anteriorly above the coronoid fossa. Results indicated statistically significant differences between intact state and shorter megaprostheses relative to longer megaprostheses and proximally between intact and implanted bones. Varying levels of stress shielding were recorded across multiple slices for all megaprosthesis lengths. The degree of stress shielding increased with implant lengthening being 2-4 times in C and D compared to B. Axial loading of the humerus can occur with direct loading on outstretched upper limbs or indirectly through the elbow. Resultant stress shielding effect predicted in longer megaprosthesis models may become clinically relevant in repetitive axial loading during activities of daily living. It is recommended to use shorter megaprosthesis to prevent failure

Resection of the proximal femur raises several challenges to the orthopedic oncology surgeon. Among these is the re-establishment of the abductor mechanism that might impacts on hip function. Extent of tumor resection and surgeons’ preferences dictate the reconstruction method of the abductors. While some surgeons advocate the necessity of greater trochanter (GT) preservation whenever possible, others attempt direct soft tissues reattachment to the prosthesis. Sparse data in the literature evaluated the outcomes of greater trochanter fixation to the proximal femur megaprosthesis. This is a retrospective monocentric study. All patients who received a proximal femoral replacement after tumor resection between 2005 and 2021 with a minimum follow-up of three months were included. Patients were divided into two groups: (1) those with preserved GT reattached to the megaprosthesis and (2) those with direct or indirect (tenodesis to fascia lata) abductor muscles reattachment. Both groups were compared for surgical outcomes (dislocation and revision rates) and functional outcomes (Trendelenburg gait, use of walking-assistive device and abductor muscle strength). Additionally patients in group 1 were subdivided into patients who received GT reinsertion using a grip and cables and those who got direct GT reinsertion using suture materials and studied for GT displacement at three, six and 12 months. Time to cable rupture was recorded and analyzed through a survival analysis. Fifty-six patients were included in this study with a mean follow-up of 45 months (3-180). There were 23 patients with reinserted GT (group 1) and 33 patients with soft tissue repair (group 2). Revision rate was comparable between both groups(p=0.23); however, there were more dislocations in group 2 (0/23 vs 6/33; p=0.037). Functional outcomes were comparable, with 78% of patients in group 1 (18/23) and 73% of patients in group 2 (24/33) that displayed a Trendelenburg gait (p=0.76). In group 1, 70% (16/23) used walking aids compared to 79% of group 2 (27/33) (p=0.34). Mean abductor strength reached 2.7 in group 1 compared to 2.3 in group 2 (p=0.06). In group 1, 16 of the 23 patients had GT reinsertion with grip and cables. Median survival of cables for these 16 patients reached 13 months in our series. GT displacement reached a mean of two mm, three mm, and 11 mm respectively at three, six and 12 months of follow-up in patients with grip and cables compared to 12 mm, 24 mm and 26 mm respectively at the same follow-up intervals in patients with GT stand-alone suture reinsertion(p<0.05). Although GT preservation and reinsertion did not improve functional outcomes after proximal femur resection and reconstruction with a megaprosthesis, it was significantly associated with lower dislocation rate despite frequent cable failure and secondary GT migration. No cable or grip revision or removal was recorded. Significantly less displacement was observed in patients for whom GT reattachment used plate and cables rather than sutures only. Therefore we suggest that GT should be preserved and reattached whenever possible and that GT reinsertion benefits from strong materials such as grip and cables

Aim. Megaprosthesis have become a standard option in limb preserving surgery after bone resection in musculoskeletal tumors. Recently they have also been used in complex revision arthroplasty in cases with massive bone loss. The aim of this study was to analyze the incidence of periprosthetic joint infection (PJI) both in primary oncology cases and aseptic revision cases and analyze which are the significant risk factors for PJI with a special interest on the use of prophylactic antibiotic loaded calcium sulfate beads. Method. All patients undergoing surgery with the use of megaprosthesis in our institution between January/2012 and December/2022 were retrospectively reviewed. Data was collected from electronic medical records. We identified 108 procedures involving megaprosthesis in 90 patients with an average follow-up of 37 months. Indications were 79 primary musculoskeletal tumors and 29 aseptic complex revision arthroplasty. Results. Table 1 shows relevant clinical information. No significant risk factor was found either in uni or multivariate analysis. PJI rate was 15% (12/79) for primary musculoskeletal surgery and 31% (9/29) for complex revision surgery. The use of antibiotic loaded calcium sulfate beads did not show an advantage – 22% (9/41) with vs. 18% (12/67) without. Conclusions. In this relatively small series it was not possible to show a significal association between PJI and certain known risk factors such as gender, ASA score, site of surgery (knee) and revision surgery. The use of antibiotic loaded calcium sulfate beads as prophylaxis was not beneficial in reducing PJI rates in our cohort. We acknowledge the limitations of our study: a small sample group, in a single institution with heterogeneity in terms of diagnosis and surgical site. We recognize the need for a multicentric study with a larger cohort to validate these findings. For any tables or figures, please contact the authors directly

Aim. Periprosthetic joint infections are a devastating complication after modular endoprosthetic reconstruction following resection of a musculoskeletal tumour. Due to long operating times, soft tissue dissection and immunosuppression, the infection rate after limb salvage is high and ranges between 8% and 15%. The aim of this retrospective single centre study was to assess the reinfection and re-reinfection rate after septic complications of megaprostheses. Method. In this retrospective study, 627 patients with a primary replacement of a musculoskeletal tumour of the lower limb and reconstruction by a megaprosthesis were recorded from 1983 – 2016. 83 out of 621 patients available for follow-up experienced an infection (13.4%). Two patients were treated with debridement and removal of the mobile parts, 61 patients with a one-stage revision, 16 patients with a two-stage revision, and 4 patients with an amputation. The mean follow up was 133 months (range: 2 – 423 months). Results. The reinfection rates after debridement, one-stage revision, two-stage revision, and amputation were 100% (CI 95%: 20 −100%), 49% (CI 95%: 36 – 62%), 38% (CI 95%: 6 – 76%), and 0%, respectively. A reinfection occurred after a mean of 38,7 months (range: 0 to 201 months). The most commonly isolated microorganisms were coagulase negative Staphylococci, followed by Staphylococcus aureus. A re-reinfection occurred in 100% after debridement, in 44% (CI 95%: 22 – 69%) after one-stage revision, in 55% (CI 95%: 31 – 91%) after two-stage revision, and 0% after amputation. Regarding two-stage revision, there was a statistically significant difference in infection rates between patients treated with complete removal of the megaprosthesis and patients with at least one retained component (Fisher's exact test, p = 0.027). Conclusions. Septic failures after megaprosthesis reconstruction of a musculoskeletal tumour of the lower limb are difficult to treat and show high reinfection and re-reinfection rates. A two-stage revision with removal of all components showed the best results among limb salvage procedures for periprosthetic megaprosthesis infection

Abstract. Introduction. Patients presenting with loosening or a fracture between ipsilateral hip and knee replacements provide a unique reconstructive challenge. We present mid-term results of the cement-over megaprosthesis (COM) when managing these complex cases. A COM is cement-linked to the stem of a well-fixed existing implant. We report the largest series to date and show that this may be preferable to total femoral replacement in a cohort of patients who often have significant co-morbidities. Methodology. A retrospective analysis of patients undergoing COM between 2002–2022 was performed. Primary outcomes were defined as implant survival, displayed with survival analysis. Secondary outcomes included mortality and surgical complications. Functional outcomes included Visual Analogue Score (VAS), EuroQol-5D-3L and Musculoskeletal Tumour Society (MSTS) score at one year post operatively. Results. 34 patients underwent reconstructive cement-over technique. There were 20 custom distal femur replacements and 10 custom proximal femoral replacements. Two patients were revised, with a ten year implant survival of 94%. Fifteen patients died during the study period with an mean time to death of 66 months (25–109). The mean follow up was 75 months. 11 patients (32%) developed surgical complications. Mean VAS score was 4.9 (1–10), EuroQol-5D-3L index 0.45 (−0.59 – 0.88) and MSTS score was 16.8 (2–27) in 29 patients. Conclusion. The COM technique provides good implant survivorship in complex cases with compromised bone stock and this series confirms this as an established alternative to total femoral replacement in these cases

Introduction. The development of new megaprosthesis for the treatment of large bone defects has offered important opportunities to orthopedic oncologic surgeons for the replacement of skeletal segments such as the long bones of the upper and lower limbs and the relative joints. Our experience, treating non union and severe bone loss, has brought us, sometimes, to be confronted with the reality of some failures after unsuccessful attempts to reconstruct. Faced with certain radiological and / or clinical drastic situations we wanted to apply the principles of Biological Chamber and oncologic surgery with megaprosthetic replacement solutions. We implanted megaprosthesis with either 1 step or 2 steps (previous antibiotated spacer) technique depending on the septic patient conditions. The aim of this study is to retrospectively evaluate both clinical and radiological outcomes in patients underwented to a lower limb megaprosthesis implant and complications were recorded. Materials and Methods. In total, we treated 58 patients with megaprosthesis mono-and bi-articular subdivided as follows: proximal femur, distal femur, proximal tibia and total femur. The mean follow-up of patients is about 24 months (5 yrs max, min 6 months) with clinical and serial radiographic revaluations with standard methods (X-ray in 45 days, 3–6-12-18-24 months) as well as monitoring of blood parameters of inflammation for at least 2 months. Results. Despite the follow up average is not so long, the first patients have now reached five years of monitoring and in all cases we have had encouraging clinical results with good articulation of the segments, no somato-sensory or motorial defict and acceptable functional recovery. During surgery and, even more, in the pre-operative planning much attention should be given to the evaluation of the extensor apparatus preserving it and, when necessary, reinforcing it with tendon substitutes. Discussion. Megaprosthesis in traumatic and prosthetic failures can therefore be considered, in extreme cases appropriately selected, as a solution available to the orthopedic surgeon? In oncological surgery the opportunity to regive a function, although not ad integrum, to the patient is certainly an element of great fascination for the surgeon and an opportunity for the patient. Unfortunately, the high mortality associated with this disease does not allow us to have long-term follow-up. This then creates a lack of certainty about the survival of this type of prosthesis and the medium and long-term complications that may occur. Nevertheless, the patients treated by us should be considered as a oncologic patient, not because of the disease but for the limited therapeutic options available. Conclusions. We can consider megaprosthesis as a valuable opportunity to restore functionality to patients who are, despite themselves, to deal with highly disabling diseases

Aim. Rifampicin and fluoroquinolone based therapy is generally considered as first-choice targeted oral antimicrobial therapy for staphylococcal prosthetic joint infections (PJI) treated with debridement, antibiotics and implant retention (DAIR). Alternative equally effective antimicrobial strategies are urgently needed due to toxicity and drug-drug interactions that frequently occur with this strategy. Data from recent clinical studies suggests equipoise for other antimicrobial treatment regimens. The objective of the Rifampicin Combination Therapy versus Targeted Antimicrobial Monotherapy in the Oral Antimicrobial Treatment Phase of Staphylococcal Prosthetic Joint Infection (RiCOTTA)-trial is to evaluate whether monotherapy with clindamycin is non-inferior to rifampicin/fluoroquinolone combination therapy in patients with staphylococcal PJI that are treated with DAIR. Method. The RiCOTTA-trial is a multicenter, non-inferiority, open-label, randomized controlled trial evaluating clindamycin versus rifampicin/fluoroquinolone combination therapy in the oral treatment phase in patients with staphylococcal PJI managed with DAIR. The trial is performed in 16 hospitals in the Netherlands. Eligible patients are adults with staphylococcal knee or hip PJI managed by DAIR. Patients are included one to six days before antibiotic treatment is switched from intravenous to oral therapy. Patients with a contraindication for rifampicin, with a megaprosthesis or who receive intravenous antibiotics for more than three weeks after initial debridement are excluded. Primary outcome is treatment success one year after finishing antimicrobial treatment. Success is defined as the absence of: i. Infection related re-surgery, ii. New episode of antibiotic treatment for infection of the index joint after the initial treatment phase of 12 weeks, iii. Ongoing use of antibiotics for the index joint at the end of follow-up, iv. Death. The estimated treatment success of rifampicin combination therapy is 85% and the monotherapy strategy is considered not inferior when the difference in treatment success will be less than 10%. Enrolment of 158 patients per group (316 in total) is needed to confirm non-inferiority of monotherapy with a power of 80%. The trial is currently open for enrolment. The study is approved by the Medical Ethics Committee Leiden, the Hague, Delft, the Netherlands and registered under EU trial number 2022-501620-26-00 in Clinical Trial Information System. Conclusions. Currently, the RiCOTTTA study is the largest randomised clinical trial that compares targeted oral monotherapy with rifampicin combination treatment for staphylococcal PJI. Noninferiority of monotherapy would result in a change in national PJI guidelines and enable clinicians to use a more patient-tailored approach when considering antibiotics for patients during the oral treatment phase of PJI

INTRODUCTION. Recently the evolution of prosthesis technology allows the surgeon to replace entire limbs. These special prostheses or megaprostheses were born for the treatment of severe oncological bone loss. Recently, however, the indications and applications of these devices are expanding to other orthopaedic and trauma situations. Since some years we are implanting megaprostheses in non-oncological conditions such as septic post-traumatic failures represented by complex non-unions and critical size bone defects. The purpose of this study is to retrospectively evaluate the clinical outcome of this treatment and register all the complications and infection recurrence. MATERIAL AND METHOD. Between January 2008 and January 2016 we have treated 55 patients with septic post-traumatic bone defects In 48/55 cases we perform a 2 steps procedure: 1° step: resection, debridment, devices removal and antibiotic spacer implantation; 2° step: spacer removal and megaprosthesis implantation. In 7/55 patients in whom all the femur was infected, we performed a one step procedure by the complete removal of the femur and a megaprosthesis (Total Femur) implantation. RESULTS. We obtained good results from a clinical, laboratory and radiological point of view with restoration of the function of the affected limb. Only in 5/55 cases the infection recurred. All the Total Femur megaprosthesis implanted in a one step procedure healed without recurrence of infection. CONCLUSION. Megaprosthesis in severe septic bone loss can be considered, in extreme cases appropriately selected, as an available solution for the orthopedic surgeon. The two steps procedure gives the best results with safety and lower infection recurrence creating a membrane (Chamber Induction Technique) that can protect the prosthesis in a safe environment. We can perform a one step procedure only when all the infected segment is entirely removed. This type of complex surgery must be performed in specialized centers where knowledge and technologies are present

The use of new megaprosthesis for massive bone loss is an option for the replacement of skeletal segments. There are several clinical scenarios that can be associated with this situation including severe trauma with multiple failed osteosynthesis with a non union or with a previous prosthetic replacement of a neighbouring joint; multiple revision of arthroplasty with or without infections or large resections of tumours. The aim of this work is to evaluate retrospectively both clinical and radiological outcomes and any complications in patients treated with megaprosthesis in SEPTIC BONE DEFECTS in our Hospital from February 2012 to January 2015. From February 2012 to January 2014 a total of 20 patients were treated with mono-and bi-articular megaprosthesis subdivided as follows: 4 proximal femur, 11 distal femur, 3 total femur, 1 total humerus and 1 proximal humerus. Clinical and serial radiographic evaluations were performed at 6 weeks, 3, 6, 12, 18 and 24 months. Blood parameters with CRP and ESR were monitored for at least 2 months. The mean follow-up of patients was about 24.4 months (range 5 months to 31 months). The mean age of the patients was 53 years (range 37–80years). Of the patients 20, 9 were female and 11 were male. The aetiology was: 11 septic non unions, 3 infected TKA, 4 infected THR and 2 infected tumor prostheses. We have evaluated retrospectively both clinical and radiological outcomes of 20 patients. They had large bone defects that threatened the viability of the limb. They were treated with megaprosthesis. Although the mean length of follow-up was only 24.4 months they showed encouraging clinical results, with good articulation of the segments, no somato-sensory or motor deficit and acceptable functional recovery. There were three cases of dislocation, one case with rifampicin toxicity, one case with acute prosthetic infection (case that needed debridement and one case with chronic oral antimicrobial. Megaprosthesis provides a valuable opportunity to restore functionality to patients with highly disabling diseases. The number of complications is not depreciable

We reviewed 25 patients in whom a MUTARS megaprosthesis with a conical fluted stem had been implanted. There were three types of stem: a standard stem was used in 17 cases (three in the proximal femur, nine in the distal femur and five proximal tibia), a custom-made proximal femoral stem in four cases and a custom-made distal femoral stem in four cases. The mean age of the patients was 40.1 years (17 to 70) and the mean follow-up was for 2.5 years (0.9 to 7.4). At follow-up two patients had died from their disease: one was alive with disease and 22 were disease-free. One of 23 prostheses had been removed for infection and another revised to a cemented stem. The mean Musculoskeletal Tumor Society score was 24.9 (12 to 30) and the mean Karnofsky index was 82% (60% to 100%). There was no radiological evidence of loosening or subsidence. Stem stress shielding was seen in 11 patients and was marked in five of these. There were five complications, rupture of the extensor mechanism of the knee after extra-articular resection in two patients, deep venous thrombosis in one, septic loosening in one, and dislocation of the hip in one. The survival rate after seven years was 87% (95% confidence interval (CI) 83 to 91) for the patients and 95% (95% CI 91 to 99) for the megaprosthesis. A longer follow-up is needed to confirm these encouraging results

The reconstruction of lower limb defects after oncological reconstructions is still a problem in limb salvage surgery. Large bony defects need to be treated with sound and durable reconstructions. During recent decades, the life expectancy of patients affected with cancer has improved considerably because of advances in chemotherapy, immunotherapy, hormonal treatment and radiotherapy. This improvement requires greater reliability in the reconstructive procedure in order to avoid mechanical failure during prolonged survival of the patient. The author experience with modular megaprosthesis by Link (megasystem C) allowed us to present a rapid, effective and functional solution. From June 2001 to December 2007 225 patients have been operated with a megaprosthesis C for tumoral resection. The new megaprosthesis C by Link represents a wide-ranging system that can afford a large variety of reconstructions in the inferior limb, from very short replacement of 5 cm in proximal femur, to a total femur and proximal tibia replacement. Modularity is represented by 1 cm increase in length. The different options of cemented and not cemented stem may be used with intraoperative decision. In cemented stem a rough collar seals the osteotomy and prevents polyethylene debris from entering the femoral canal by inducing a scar tissue around the stem entrance (so-called purse-string effect). Moreover in patients with solitary lesions and very good prognosis an allograft-prosthesis composite can be performed with improved clinical results on walking and function. Of the 225 patients that underwent tumoral resection and reconstruction with a modular megaprosthesis approximately 43% (97 cases) were operated for metastatic disease. Among these cases 55 cases were proximal femoral recontructions, 39 cases were distal femoral reconstructions and 3 cases were proximal tibial reconstructions. All cases were performed with cemented stems. We experienced a 7% of postoperative infections, 2% of dislocations of proximal femoral prosthesis and 3% of mechanical failures. While infections and dislocation rates were in the average for this surgery, mechanical failures were relatively high. We should consider that in patients with relatively long resections and muscle deficiency the mechanical stress exerted on the prosthesis can explain this kind of mechanical failure. However the new design of morse tapers have annulled these problems

Introduction:. The development of new prostheses due to large resections has offered important opportunities to orthopedic surgeons mainly in oncology. A medline research can easily underline how poor is the international experience about this cases in nonunion: 75 results for megaprosthesis just 7 works in nonunion. It is proposed the experience of our department, which deals specifically with the treatment of nonunion, in cases of repeated failures to treatment. One of the most significant problems in the treatment of relapsing nonunion is the consequent worsening of joint function. Critical bone defects, sepsis, joint fractures and unclear relapsing nonunions are the most common cases for a megaprosthesis treatment. In these cases, even if it obtains the healing of nonunion the functional result would be presumptively poor. This radiological or clinical situation drove us, in such cases, to drastic solutions following the principles of cancer cases. We implanted megaprosthesis with either techniques: 1 stage or 2 stages depending on the clinical findings. In nonunion the main decision making was the septic or aseptic status. Materials and Methods:. we treated 32 patients with megaprosthesis replacing the nearest joint to the nonunion segment or both the proximal e distal one as follows: proximal femur, distal femur, proximal tibia, and total femur. The mean follow-up of patients is 12 months (2 yrs max, min 3 months). Clinical and serial radiographic evaluations with standard methods (RX in 45 days, 3-6-12-24 months) was performed; as well as monitoring of blood parameters for 2 months. Results:. Despite the average follow-up is not high, we do not aspect main differences to oncologic survival of the device, so our expectations and main interest to our experience is faced to the functional status of these patients and clinical evaluation in septic cases. In all cases, however, we get encouraging clinical results with such prosthesis. Complications: no neurologic defect was observed. The main surgical difficulty was the chronic reducing of the range of motion of the extending mechanism of the knee, usually not involved in such a way in oncologic cases. In these cases we were forced to reinforce mainly the patellar tendon with tendon substitutes. Discussion:. mega-prosthesis in post-traumatic cases can be considered, in extreme cases, as an available solution to the orthopedic surgeon. In oncological surgery the opportunity to get back to a good function although not a “restitution ad integrum” is a success, if it is possible to eradicate the tumor. Unfortunately, the high mortality associated with this disease does not allow us to have long-term follow-up due to the big amount of cases lost at the follow up. This situation creates a lack of certainty about the survival of this type of prosthesis and the medium-and long-term complications that may occur. Nevertheless, the patients treated by us should be considered oncological patients, not because of the disease but for the limited therapeutic options available. Conclusions:. We have to consider not mega-prosthesis more like a pipe dream, but rather, as a viable opportunity

Systemic metal ion monitoring (Co;Cr) has proven to be a useful screening tool for implant performance to detect failure at an early stage in metal-on-metal hip arthroplasty. Several clinical studies have reported elevated metal ion levels after total knee arthroplasty (TKA), with fairly high levels associated with rotating hinge knees (RHK) and megaprostheses. 1. In a knee simulator study, Kretzer. 2. , demonstrated volumetric wear and corrosion of metallic surfaces. However, prospective in vivo data are scarce, resulting in a lack of knowledge of how levels evolve over time. The goal of this study was to measure serum Co and Cr levels in several types TKA patients prospectively, evaluate the evolution in time and investigate whether elevated levels could be used as an indicator for implant failure. The study was conducted at Ghent University hospital. 130 patients undergoing knee arthroplasty were included in the study, 35 patients were lost due to logistic problems. 95 patients with 124 knee prostheses had received either a TKA (primary or revision) (69 in 55 patients), a unicompartimental knee arthroplasty (7 UKA), a RHK (revision −7 in 6 patients) or a megaprosthesis (malignant bone tumours − 28 in 27 patients). The TKA, UKA and RHK groups were followed prospectively, with serum Co and Cr ions measured preoperatively, at 3,6 and 12 months postoperatively. In patients with a megaprosthesis, metal ions were measured at follow-up (cross-sectional study design). In primary knees, we did not observe an increase in serum metal ion levels at 3, 6 or 12 months. Two patients with a hip arthroplasty had elevated preTKA Co and Cr levels. There was no difference between unilateral and bilateral knee prostheses. In the revision group, elevated pre-revision levels were found in 2 failures for implant loosening. In both cases, ion levels decreased postoperatively. In revisions with a standard TKA, there was no significant increase in metal ions compared to primary knee arthroplasty. RHK were associated with a significant increase in Co levels even at short-term (3–12 months). The megaprosthesis group had the highest metal ion levels and showed a significant increase in Co and Cr with time in patients followed prospectively. With the current data, we could not demonstrate a correlation between metal ion levels, size of the implant or length of time in situ. In primary knee arthroplasty with a standard TKA or UKA, metal ion levels were not elevated till one year postoperatively. This suggests a different mechanism of metal ion release in comparison to metal-on-metal hip arthroplasties. In two cases of revision for implant loosening, pre-revision levels were elevated, possibly associated with component wear, and decreased after revision. With RHK, slightly elevated ion levels were found prospectively. Megaprostheses had significantly elevated Co and Cr levels, due to corrosion of large metallic surfaces and/or wear of components which were not perfectly aligned during difficult reconstruction after tumour resection. Further research is needed to assess the clinical relevance of metal ion levels in knee arthroplasty

Introduction. Systemic metal ion monitoring (Co;Cr) has proven to be a useful screening tool for implant performance to detect failure at an early stage in metal-on-metal hip arthroplasty. Several clinical studies have reported elevated metal ion levels after total knee arthroplasty (TKA), with fairly high levels associated with rotating hinge knees (RHK) and megaprostheses. 1. In a knee simulator study, Kretzer. 2. , demonstrated volumetric wear and corrosion of metallic surfaces. However, prospective in vivo data are scarce, resulting in a lack of knowledge of how levels evolve over time. The goal of this study was to measure serum Co and Cr levels in several types TKA patients prospectively, evaluate the evolution in time and investigate whether elevated levels could be used as an indicator for implant failure. Patients and Methods. The study was conducted at Ghent University hospital. 130 patients undergoing knee arthroplasty were included in the study, 35 patients were lost due to logistic problems. 95 patients with 124 knee prostheses had received either a TKA (primary or revision) (69 in 55 patients), a unicompartimental knee arthroplasty (7 UKA), a RHK (revision −7 in 6 patients) or a megaprosthesis (malignant bone tumours − 28 in 27 patients) (Fig 1). The TKA, UKA and RHK groups were followed prospectively, with serum Co and Cr ions measured preoperatively, at 3,6 and 12 months postoperatively. In patients with a megaprosthesis, metal ions were measured at follow-up (cross-sectional study design). Results (Fig 2 and 3). In primary knees, we did not observe an increase in serum metal ion levels at 3, 6 or 12 months. Two patients with a hip arthroplasty had elevated preTKA Co and Cr levels. There was no difference between unilateral and bilateral knee prostheses. In the revision group, elevated pre-revision levels were found in 2 failures for implant loosening. In both cases, ion levels decreased postoperatively. In revisions with a standard TKA, there was no significant increase in metal ions compared to primary knee arthroplasty. RHK were associated with a significant increase in Co levels even at short-term (3–12 months). The megaprosthesis group had the highest metal ion levels and showed a significant increase in Co and Cr with time in patients followed prospectively. With the current data, we could not demonstrate a correlation between metal ion levels, size of the implant or length of time in situ. Discussion. In primary knee arthroplasty with a standard TKA or UKA, metal ion levels were not elevated till one year postoperatively. This suggests a different mechanism of metal ion release in comparison to metal-on-metal hip arthroplasties. In two cases of revision for implant loosening, pre-revision levels were elevated, possibly associated with component wear, and decreased after revision. With RHK, slightly elevated ion levels were found prospectively. Megaprostheses had significantly elevated Co and Cr levels, due to corrosion of large metallic surfaces and/or wear of components which were not perfectly aligned during difficult reconstruction after tumour resection. Further research is needed to assess the clinical relevance of metal ion levels in knee arthroplasty. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

The use of megaprosthesis presents a major advancement in orthopaedic oncology in the treatment of malignant bone and soft tissue tumours. In the present study, we retrospectively analyse the complication rate of limb salvage surgery with megaprosthesis due to malignant tumours treated in our unit. From 1997 until 2006, 64 patients (37 men, 27 women), aged between 16–78 years old (mean 43.3), have been treated with megaprosthesis insertion. The diagnosis was metastatic bone lesions in 26 patients, osteosarcoma in 14, chondrosarcoma in 14, soft tissue sarcoma with osseous involvement in 3 (2 synovial sarcoma and 1 MPNST), malignant giant cell tumour in 3, angiosarcoma in 2, Ewing sarcoma in 1, and revision of a failed reconstruction in 1 patient. Lower extremity reconstruction included proximal femur (30 patients), distal femur (19), proximal tibia (3) and total femur replacement (4). Upper extremity procedures were proximal humerus (7 patients) and distal humerus reconstruction (1). Sixty patients were available for follow-up (minimum 1 year, mean 4.2 years). The following complications were encountered: periprosthetic fracture (1 patient), deep infection (4), superficial wound infection (6), local recurrences (2), hip dislocation (3), knee extensor apparatus failure (2), skin necrosis, (3) unsuccessful vascular reconstruction (1). The deep infection led to hip disarticulation in 1 patient and Tikhoff-Linberg resection in 1 patient with proximal humerus prosthesis. A rare case of bone leismaniasis was also encountered (treated conservatively). Limb salvage surgery is the mainstay of treatment in malignant musculoskeletal tumours. Special megaprosthesis has been developed for this purpose. Survival rate is substantially less than common prosthesis; the complication rate is increased, especially regarding wound healing complications and infection. Adverse prognostic factors are:. a) advanced age,. b) the amount of soft tissues that need to be excised,. c) prolonged surgical time, and. d) reconstruction about the knee

The treatment of bone metastases is usually palliative and aims to achieve adequate control of pain, to prevent and resolve compression of the cord in lesions of the spine and to anticipate or stabilise pathological fractures in the appendicular skeleton. In selected cases the complete resection of an isolated bone metastasis may improve the survival of the patient. During recent decades, the life expectancy of patients affected with metastatic carcinoma has improved considerably because of advances in chemotherapy, immunotherapy, hormonal treatment and radiotherapy. This improvement requires greater reliability in the reconstructive procedure in order to avoid mechanical failure during prolonged survival of the patient. The author experience with modular megaprosthesis by Link (megasystem C) allowed us to present a rapid, effective and functional solution. From June 2001 to December 2007 225 patients have been operated with a megaprosthesis C for tumoral resection. The new megaprosthesis C by Link represents a wide-ranging system that can afford a large variety of reconstructions in the inferior limb, from very short replacement of 5 cm in proximal femur, to a total femur and proximal tibia replacement. Modularity is represented by 1 cm increase in length. The different options of cemented and not cemented stem may be used with intraoperative decision. In cemented stem a rough collar seals the osteotomy and prevents polyethylene debris from entering the femoral canal by inducing a scar tissue around the stem entrance (so-called purse-string effect). Moreover in patients with solitary lesions and very good prognosis an allograft-prosthesis composite can be performed with improved clinical results on walking and function. Of the 225 patients that underwent tumoral resection and reconstruction with a modular megaprosthesis approximately 43% (97 cases) were operated for metastatic disease. Among these cases 55 cases were proximal femoral recontructions, 39 cases were distal femoral reconstructions and 3 cases were proximal tibial reconstructions. All cases were performed with cemented stems. We experienced a 7% of postoperative infections, 2% of dislocations of proximal femoral prosthesis and 3% of mechanical failures. While infections and dislocation rates were in the average for this surgery, mechanical failures seemed relatively high. However in patients with relatively long resections and muscle deficiency the mechanical stress exerted on the prosthesis can explain this kind of mechanical failure

The June 2015 Oncology Roundup. 360 . looks at: Infection in megaprosthesis; Impressive results for mid femoral reconstruction; Revered teaching or old myth? Femoral neck protection in metastatic disease; Megaprosthesis about the knee; Malignant transformation in multiple hereditary exostoses; Fracture of intercalary bone allograft; Comorbidity and outcomes in sarcoma; A worrying turn? Use of denosumab for giant cell tumour of bone