We present our mid-term results with the use of structural allografts in cases of revision of failed THA due to infection. Eighteen patients with a deep infection at the site of a THA were treated with a two-stage revision, which included reconstruction with massive allografts. All the allografts were frozen and sterilised by gamma-irradiation. The mean age at the time of the revision was 65.9 years. A cement spacer containing 1 g of Gentamicin was used during the interval period. Parenteral antibiotics were administrated for a period of three to four weeks. Oral antibiotics were given for an average of 18 weeks. The patients were followed for a mean of 8.9 years (5.4–14.2). Definite deep wound infection developed in one patient (5.6%), who underwent resection arthroplasty. An additional patient underwent re-revision of an acetabular component for mechanical loosening. The mean HHS improved from 34.2 points preoperatively to 70.7 points at the last review. Sixteen of the patients (88.9%) had a successful outcome. Kaplan-Meier survivorship analysis predicted 80.95% rate of survival at 14 years. Radiographicly, all allografts were found to be united to host bone. There were no signs of definite loosening of any of the implants. The complications include one fracture and two postoperative recurrent dislocations. The use of massive allografts in a two-stage reconstruction for infected THA gives satisfactory results and should be considered in cases complicated with severe bone stock loss, where standard revision techniques are not an option

Management of severe bone loss in total knee arthroplasty presents a formidable challenge. This situation may arise in neglected primary knee arthroplasty with large deformities and attritional bone loss, in revision situations where osteolysis and loosening have caused large areas of bone loss and in tumor situations. Another area of large bone loss is frequently seen in periprosthetic fractures. Trabecular metal (TM) with its dodecahedron configuration and modulus of elasticity between cortical and cancellous bone offers an excellent bail out option in the management of these very difficult situations. Severe bone loss in the distal femur and proximal tibia lend themselves to receiving the TM cones. The host bone surfaces need to be prepared to receive these cones using a high speed burr. The cones acts as a filler with an interference fit through which the stemmed implant can be introduced and cemented. All areas of bone void is filled with morselised cancellous bone fragments. We present our experience of 64 TM cones (28 femoral, 36 tibial cones) over a 10-year period and our results and outcomes for the same. We have had to revise only one patient for recurrence of the tumor for which the cone was implanted in the first place. We also describe our technique of using two stacked cones for massive distal femoral bone loss and its outcomes. We found excellent osteointegration and new host bone formation around the TM construct. The purported role of possible resistance to infection in situations using the TM cones is also discussed. In summary we believe that the use of the TM cones offers an excellent alternative to massive allografts, custom and/or tumor implants in the management of massive bone loss situations

Prior to the 1970s, almost all bone sarcomas were treated by amputation. The first distal femoral resection and reconstruction was performed in 1973 by Dr Kenneth C Francis at the Memorial Sloan-Kettering Cancer Centre in New York. Since that time, limb-sparing surgery for primary sarcoma has become the mainstay of sarcoma surgery throughout the world. Initially, the use of mega-prostheses of increasing complexity, involving all the major long bones and both pelvic and shoulder girdles, was popularised. In the early 1980s, wide use of massive allograft reconstructions became widespread in both Europe and in multiple centres in the USA and UK. Since that time, increasing complexity in the design of prostheses has allowed for increasing functional reconstructions to occur, but the use of allograft has become less popular due to the development of late graft failures of patients survive past ten years. Fracture rates approaching 50% at 10 years are reported, and thus, other forms of reconstruction are being sought. Techniques of leg lengthening, and bone docking procedures to replace segmental bone loss to tumour are now employed, but the use of biological vascularised reconstructions are becoming more common as patient survivorship increases with children surviving their disease. The use of vascularised fibular graft, composite grafts and re-implantation of extra-corporeally irradiated bone segments are becoming more popular. The improvement in survivorship brought about the use of chemotherapy is producing a population of patients with at least a 65% ten year survivorship, and as many of these patients are children, limb salvage procedures have to survive for many decades. The use of growing prostheses for children have been available for some 25 years, first commencing in Stanmore, UK, with mechanical lengthening prostheses. Non-invasive electro-magnetic induction coil mechanisms are now available to produce leg lengthening, with out the need for open surgery. Whilst many of these techniques have great success, the area of soft tissue attachment to metallic prostheses has not been solved, and reattachment of muscles is of great importance, of course, for return of function. There are great problems in the shoulder joints where sacrifice of rotator cuff muscles is necessary in obtaining adequate disease clearance at the time of primary resection, and a stable shoulder construct, with good movement, has yet to emerge. Similar areas of great difficultly remain the peri-acetabular and sacro-iliac resections in the pelvis. Perhaps the real future of the art of limb salvage will be in the reconstruction of failed major joint replacements where there is great loss of bone stock, and already massive tumour prostheses are providing a salvage pathway for failed standard joint replacement. The final future for limb salvage, however, may not rest with increasing surgical complexity and innovation, but with the development of molecular biology and specific targeted treatments, according to the cytogenetics of a particular tumour. We are on the threshold of yet another quantum change in the approach to cancer management; just as chemotherapy brought a tremendous change in the 1970s, molecular biology is the frontier to make much of the current limb salvage surgery that is performed redundant

When is revision surgery contraindicated in the face of a failed total hip? Surgically indicated can be interpreted as a situation where the patient will benefit from a specific intervention, with sufficient likelihood, to warrant the risks of intervention. Contraindication connotes the opposite; the risks, or likelihood of the intervention's failure to achieve the desired results outweigh the expected extent and likelihood of benefit. Contraindicated actually represents the end point of a complex decision making process which must be carried out by the practitioner in conjunction with the patient and may require the full range of the surgeons analytical, technical and communication skills. Most commonly the term means that the surgeon's thinking has led to a belief that the patient will be better off without further surgery. Deciding to forego another revision usually means leaving the patient with a resection arthroplasty. Relative indications for resection, or even avoiding revision of a failed arthroplasty, are most commonly biological. In a healthy host, with a sterile but anatomically deficient bed with adequate soft tissue coverage, mechanical reconstruction capabilities and massive bulk allograft may allow reconstruction of almost any amount of tissue loss. Severe osteomyelitis or soft tissue infection, unmanageable for reasons, including but not limited to: chronic immune-suppression, mixed or resistant organisms or a life threatening sensitivity to antibiotics which may be required to treat the sepsis. More subjective factors, such as adequacy of soft tissue and bone stock, comorbid medical conditions or a patient's desire to avoid additional surgery as well as costs must be considered. This decision may include dozens of other considerations, some of which may be considered pre-operatively and some which may only arise intra-operatively

Treatment of Paprosky type 3A and 3B defects in revision surgery of a hip arthroplasty is challenging. In previous cases such acetabular defects were treated with massive structural allograft bone reconstructions using cemented all-polyethylene cups. In our department we started using custom made triflanged cups to restore the articulation of the hip. The triflanged cups were designed on the basis of CT-image analysis. We are using a new type of implant construction technique with additive technology. This is a production process consisting of ion beam sintering joining metal powder particles layer upon layer on the basis of a 3D model data. The production technique is similar to rapid prototyping manufacturing. 7 Patients have been treated with this new technique. The case studies will be presented with their clinical and radiographic follow-up. We think that additive technology is a breakthrough in treating this kind of severe acetabular defects

In the revision situation, there are times where larger heads are just not enough to obtain and maintain stability. The two most relevant times that this is the case is in patients with very lax tissues, or in patients with insufficient or absent soft tissues, especially abductor mechanisms. In addition, in cases where a revision is being performed for dislocation and components looked well-positioned, constrained liners have been extremely beneficial in our hands. Constrained acetabular liners have been available for close to two decades. Two basic types of liners are available. The type first developed by Joint Medical Products was the SROM constrained liner which captured the femoral head with a locking ring in the polyethylene. These liners may have better results with larger head sizes because the hip can be taken through a larger range of motion (with larger head sizes) before the locking ring is stressed. The second type of constraining liner was developed by Osteonics (Stryker). It consisted of a tripolar replacement which is constrained by a locking ring in the outer polyethylene of the device. Indications for constrained liners include patients undergoing primary arthroplasty who are low demand and have dementia or hip muscle weakness or spasticity. Indications for constrained liners in the revision situation include cases with previously failed operations for instability, elderly low demand patients with instability, cases with poor or absent hip musculature, and cases with well positioned acetabular and femoral components and with hip instability. In this last scenario we cement the liners into fixed shells. Our results at average 10-year follow-up in 101 hips, demonstrate a 6% failure of the device. Four hips were revised for acetabular loosening and four hips for femoral loosening. One additional hip was revised for acetabular osteolysis. Considering the difficulty of the cases we consider these results to be quite encouraging. At average 3.9 year follow-up of 31 cases where the liner was cemented into the secure shell only one case failed by dislodgement of the liner and one case by fracture of the locking mechanism. Our experience has led to the following technical recommendation: (1) if cementing the component score the liner and make sure it is contained within the shell (2) avoid inserting the liner into a grossly malpositioned shell (3) avoid positioning the elevated rim of the liner into a position where impingement might occur and (4) avoid placing the shell and constrained liner in cases with massive acetabular allografts unless additional fixation, i.e. cages, are utilized. Especially in the elderly, these liners are our components of choice for many pre-operative and intra-operative cases of instability

Primary malignant bone tumor often requires a surgical treatment to remove the tumor and sometimes restore the anatomy using a frozen allograft. During the removal, there is a need for a highest possible accuracy to obtain a wide safe margin from the bone tumour. In case of reconstruction using a bone allograft, an intimate and precise contact at each host-graft junction must be obtained (Enneking 2001). The conventional freehand technique does not guarantee a wide safe margin nor a satisfying reconstruction (Cartiaux 2008). The emergence of navigation systems has procured a significant improvement in accuracy (Cartiaux 2010). However, their use implies some constraints that overcome their benefits, specifically for long bones. Patient-specific cutting guides become now available for a clinical use and drastically simplify the intra-operative set-up. We present the use of pre-operative assistances to produce patient-specific cutting guides for tumor resection and allograft adjustment. We also report their use in the operative room. We have developed technical tools to assist the surgeon during both pre-operative planning and surgery. First, the tumor extension is delineated on MRI images. These MRI images are then merged with Computed Tomography scans of the patient. The tumor and the CTscan are loaded in custom software that enables the surgeon to define target (desired) cutting planes around the tumor (Paul 2009) including a user-defined safe margin. Finally, cutting guides are designed on the virtual model of the patient as a mould of the bone surface surrounding the tumor, materialising the desired cutting planes. When required, a massive bone allograft is selected by comparing shapes of the considered patient's bone and available allografts. The resection planes are transferred onto the selected allograft and a second guide is designed for the allograft cutting. The virtually-designed cutting guides are then manufactured by a rapid prototyping machine using biocompatible material. This procedure has been used to excise a local recurrence of a tibial sarcoma and reconstruct the anatomy using a frozen tibial allograft. The pre-operative planning using virtual models of the patient's bone, tumor and the available allografts enabled the surgeon to localise the tumor, define the desired cutting planes and select the optimal allograft. Patient- and allograft-specific guides have been designed and manufactured. A stable and accurate positioning of guide onto the patient's tibia was made easier thanks to the plate formerly put in place during the previous surgery. An accurate positioning of the allograft cutting guide has been obtained thanks to its design. The obtained reconstruction was optimal with a adjusted allograft that was perfectly fitting the bone defect. The leg alignment was also optimally restored. Computer assistances for tumor surgery are progressively appearing. We have presented at CAOS 2010 an optical navigation system for tumor resection in the pelvis that was promising. However, such a tool is not well adapted for long bones. We have used patient-specific guides on a clinical case to assess the feasibility of the technique and check its accuracy in the resection and reconstruction. The surgeon has benefited from the 3D planning to define his strategy. He had the opportunity to select the optimal transplant for his patient and plan the same cuttings for the allograft and the patient. During the surgery, guide positioning was straightforward and accurate. The bone cuttings were very easy to perform. The use of custom guides decreases the operating time when compared to the conventional procedure since there is no need for measurements between cutting trajectories and anatomical landmarks. Furthermore, the same cutting planes were performed around the tumor and onto the allograft to obtain a transplant that optimally fills the defect. We recommend the use of such an intra-operative assistance for tumor surgery