Aims. The purpose of this study was to evaluate the biological fixation of a 3D printed porous implant, with and without different hydroxyapatite (HA) coatings, in a canine model. Materials and Methods. A canine transcortical model was used to evaluate the characteristics of bone ingrowth of Ti6Al4V cylindrical implants fabricated using laser rapid manufacturing (LRM). At four and 12 weeks post-implantation, we performed histological analysis and mechanical push-out testing on three groups of implants: a HA-free control (LRM), LRM with precipitated HA (LRM-PA), and LRM with plasma-sprayed HA (LRM-PSHA). Results. Substantial bone ingrowth was observed in all LRM implants, with and without HA, at both time periods. Bone ingrowth increased from 42% to 52% at four weeks, to 60% to 65% at 12 weeks. Mechanical tests indicated a minimum shear fixation strength of 20 MPa to 24 MPa at four weeks, and 34 MPa to 40 MPa at 12 weeks. There was no significant difference in the amount of bone ingrowth or in the shear strength between the three implant types at either time period. Conclusion. At four and 12 weeks, the 3D printed porous implants exhibited consistent bone ingrowth and high mechanical shear strength. Based on the results of this study, we confirmed the suitability of this novel new additive manufacturing porous material for biological fixation by bone ingrowth. Cite this article: Bone Joint J 2019;101-B(6 Supple B):62–67

Aims. The use of a porous metal shell supported by two augments with the ‘footing’ technique is one solution to manage Paprosky IIIB acetabular defects in revision total hip arthroplasty. The aim of this study was to assess the medium-term implant survival and radiological and clinical outcomes of this technique. Methods. We undertook a retrospective, two-centre series of 39 hips in 39 patients (15 male, 24 female) treated with the ‘footing’ technique for Paprosky IIIB acetabular defects between 2007 and 2020. The median age at the time of surgery was 64.4 years (interquartile range (IQR) 54.4 to 71.0). The median follow-up was 3.9 years (IQR 3.1 to 7.0). Results. The cumulative medium-term survival of the acetabular construct was 89%. Two hips (5.1%) required further revision due to shell loosening, one hip (2.6%) due to shell dislocation, and one hip (2.6%) due to infection. The median Harris Hip Score improved significantly from 47 points (IQR 41.5 to 54.9) preoperatively to 80 points (IQR 73.5 to 88.6) at the latest follow-up (p < 0.001). Conclusion. The reconstruction of Paprosky IIIB acetabular defects with porous tantalum shells and two augments using the ‘footing’ technique showed excellent medium-term results. It is a viable option for treating these challenging defects. Cite this article: Bone Joint J 2024;106-B(5 Supple B):54–58

Aims. BoneMaster is a thin electrochemically applied hydroxyapatite (HA) coating for orthopaedic implants that is quickly resorbed during osseointegration. Early stabilization is a surrogacy marker of good survival of femoral stems. The hypothesis of this study was that a BoneMaster coating yields a fast early and lasting fixation of stems. Methods. A total of 53 patients were randomized to be treated using Bi-Metric cementless femoral stems with either only a porous titanium plasma-sprayed coating (P group) or a porous titanium plasma-sprayed coating with an additional BoneMaster coating (PBM group). The patients were examined with radiostereometry until five years after surgery. Results. At three months, the mean total translation (TT) was 0.95 mm (95% confidence interval (CI) 0.68 to 1.22) in the P group and 0.57 mm (95% CI 0.31 to 0.83) in the PBM group (p = 0.047). From two to five years, the TT increased by a mean of 0.14 mm (95% CI 0.03 to 0.25) more in the P group than in the PBM group (p = 0.021). In osteopenic patients (n = 20), the mean TT after three months was 1.61 mm (95% CI 1.03 to 2.20) in the P group and 0.73 mm (95% CI 0.25 to 1.21) in the PBM group (p = 0.023). After 60 months, the mean TT in osteopenic patients was 1.87 mm (95% CI 1.24 to 2.50) in the P group and 0.82 mm (95% CI 0.30 to 1.33) in the PBM group (p = 0.011). Conclusion. There was less early and midterm migration of cementless stems with BoneMaster coating compared with those with only a porous titanium plasma-sprayed coating. Although a BoneMaster coating seems to be important for stem fixation, especially in osteopenic patients, further research is warranted. Cite this article: Bone Joint J 2022;104-B(6):647–656

The advent of modular porous metal augments has ushered in a new form of treatment for acetabular bone loss. The function of an augment can be seen as reducing the size of a defect or reconstituting the anterosuperior/posteroinferior columns and/or allowing supplementary fixation. Depending on the function of the augment, the surgeon can decide on the sequence of introduction of the hemispherical shell, before or after the augment. Augments should always, however, be used with cement to form a unit with the acetabular component. Given their versatility, augments also allow the use of a hemispherical shell in a position that restores the centre of rotation and biomechanics of the hip. Progressive shedding or the appearance of metal debris is a particular finding with augments and, with other radiological signs of failure, should be recognized on serial radiographs. Mid- to long-term outcomes in studies reporting the use of augments with hemispherical shells in revision total hip arthroplasty have shown rates of survival of > 90%. However, a higher risk of failure has been reported when augments have been used for patients with chronic pelvic discontinuity. Cite this article: Bone Joint J 2024;106-B(4):312–318

Aims. Massive endoprostheses rely on extra-cortical bone bridging (ECBB) to enhance fixation. The aim of this study was to investigate the role of selective laser sintered (SLS) porous collars in augmenting the osseointegration of these prostheses. Materials and Methods. The two novel designs of porous SLS collars, one with small pores (Ø700 μm, SP) and one with large pores (Ø1500 μm, LP), were compared in an ovine tibial diaphyseal model. Osseointegration of these collars was compared with that of a clinically used solid, grooved design (G). At six months post-operatively, the ovine tibias were retrieved and underwent radiological and histological analysis. Results. Porous collars provided a significantly greater surface (p < 0.001) for the ingrowth of bone than the standard grooved design. Significantly greater extracortical pedicle formation was seen radiologically around the grooved design (length p = 0.002, thickness p < 0.001, surface area p = 0.002) than around the porous collars. However, the ingrowth of bone occurred from the transection site into the porous structure of both types of collar. A fivefold increase in integration was seen with the SP and a threefold increase in the LP design when compared with G (p < 0.001). Conclusion. SLS porous collars allow the direct ingrowth of more bone and are better than current designs which rely on surface ongrowth and ECBB. Cite this article: Bone Joint J 2017;99-B:276–82

The conventional method for reconstructing acetabular bone loss at revision surgery includes using structural bone allograft. The disadvantages of this technique promoted the advent of metallic but biocompatible porous implants to fill bone defects enhancing initial and long-term stability of the acetabular component. This paper presents the indications, surgical technique and the outcome of using porous metal acetabular augments for reconstructing acetabular defects. . Cite this article: Bone Joint J 2013;95-B, Supple A:103–8

Aims. Reconstruction of the acetabulum after failed total hip arthroplasty (THA) can be a surgical challenge in the presence of severe bone loss. We report the long-term survival of a porous tantalum revision acetabular component, its radiological appearance and quality of life outcomes. Patients and Methods. We reviewed the results of 46 patients who had undergone revision of a failed acetabular component with a Paprosky II or III bone defect and reconstruction with a hemispherical, tantalum acetabular component, supplementary screws and a cemented polyethylene liner. Results. After a minimum follow-up of ten years (ten to 12), the survivorship of the porous tantalum acetabular component was 96%, with further revision of the acetabular component as the end point. The ten-year survivorship, with hip revision for any reason as the end point, was 92%. We noted excellent pain relief (mean Western Ontario and McMaster Universities Arthritis Index (WOMAC) score pain 92.6, (40 to 100)) and good functional outcomes (mean WOMAC function 90.3 (30.9 to 100), mean University of California Los Angeles activity scale 5 (2 to 10)) and generic quality of life measures (mean Short Form-12 (SF-12) physical component 48.3 (18.1 to 56.8), mean SF-12 mental component 56.7 (32.9 to 70.3)). Patient satisfaction with pain relief, function and return to recreational activities were excellent. Take home message: Uncemented acetabular reconstruction using a tantalum acetabular component gives excellent clinical and quality of life outcomes at a minimum follow-up of ten years. Cite this article: Bone Joint J 2016;98-B:767–71

Metaphyseal bone loss is common with revision total knee replacement (RTKR). Using the Anderson Orthopaedic Research Institute (AORI) classification, type 2-B and type 3 defects usually require large metal blocks, bulk structural allograft or highly porous metal cones. Tibial and femoral trabecular metal metaphyseal cones are a unique solution for large bone defects. These cones substitute for bone loss, improve metaphyseal fixation, help correct malalignment, restore the joint line and may permit use of a shorter stem. The technique for insertion involves sculpturing of the remaining bone with a high speed burr and rasp, followed by press-fit of the cone into the metaphysis. The fixation and osteoconductive properties of the porous cone outer surface allow ingrowth and encourage long-term biological fixation. The revision knee component is then cemented into the porous cone inner surface, which provides superior fixation compared with cementing into native but deficient metaphyseal bone. The advantages of the cone compared with allograft include: technical ease, biological fixation, no resorption, and possibly a lower risk of infection. The disadvantages include: difficult extraction and relatively short-term follow-up. Several studies using cones report promising short-term results for the reconstruction of large bone defects in RTKR. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):118–21

Aims. The Intraosseous Transcutaneous Amputation Prosthesis (ITAP) may improve quality of life for amputees by avoiding soft-tissue complications associated with socket prostheses and by improving sensory feedback and function. It relies on the formation of a seal between the soft tissues and the implant and currently has a flange with drilled holes to promote dermal attachment. Despite this, infection remains a significant risk. This study explored alternative strategies to enhance soft-tissue integration. Materials and Methods. The effect of ITAP pins with a fully porous titanium alloy flange with interconnected pores on soft-tissue integration was investigated. The flanges were coated with fibronectin-functionalised hydroxyapatite and silver coatings, which have been shown to have an antibacterial effect, while also promoting viable fibroblast growth in vitro. The ITAP pins were implanted along the length of ovine tibias, and histological assessment was undertaken four weeks post-operatively. Results. The porous titanium alloy flange reduced epithelial downgrowth and increased soft-tissue integration compared with the current drilled flange. The addition of coatings did not enhance these effects. Conclusion. These results indicate that a fully porous titanium alloy flange has the potential to increase the soft-tissue seal around ITAP and reduce susceptibility to infection compared with the current design. Cite this article: Bone Joint J 2017;99-B:393–400

We evaluated the efficacy and biocompatibility of porous apatite-wollastonite glass ceramic (AW-GC) as an intramedullary plug in total hip replacement (THR) for up to two years in 22 adult beagle dogs. Cylindrical porous AW-GC rods (70% porosity, mean pore size 200 3m) were prepared. Four dogs were killed at 1, 3, 6 and 12 months each and six at 24 months after implantation. Radiological evaluation confirmed the efficacy of porous AW-CG as an intramedullary plug. Histological evaluation showed osteoconduction at one month and resorption of the porous AW-GC, which was replaced by newly-formed bone, at 24 months. Our findings indicate that porous AW-GC can be used clinically as an intramedullary plug in THR

We developed a new porous scaffold made from a synthetic polymer, poly(DL-lactide-co-glycolide) (PLG), and evaluated its use in the repair of cartilage. Osteochondral defects made on the femoral trochlear of rabbits were treated by transplantation of the PLG scaffold, examined histologically and compared with an untreated control group. Fibrous tissue was initially organised in an arcade array with poor cellularity at the articular surface of the scaffold. The tissue regenerated to cartilage at the articular surface. In the subchondral area, new bone formed and the scaffold was absorbed. The histological scores were significantly higher in the defects treated by the scaffold than in the control group (p < 0.05). Our findings suggest that in an animal model the new porous PLG scaffold is effective for repairing full-thickness osteochondral defects without cultured cells and growth factors

Several bisphosphonates are now available for the treatment of osteoporosis. Porous hydroxyapatite/collagen (HA/Col) composite is an osteoconductive bone substitute which is resorbed by osteoclasts. The effects of the bisphosphonate alendronate on the formation of bone in porous HA/Col and its resorption by osteoclasts were evaluated using a rabbit model. Porous HA/Col cylinders measuring 6 mm in diameter and 8 mm in length, with a pore size of 100 μm to 500 μm and 95% porosity, were inserted into a defect produced in the lateral femoral condyles of 72 rabbits. The rabbits were divided into four groups based on the protocol of alendronate administration: the control group did not receive any alendronate, the pre group had alendronate treatment for three weeks prior to the implantation of the HA/Col, the post group had alendronate treatment following implantation until euthanasia, and the pre+post group had continuous alendronate treatment from three weeks prior to surgery until euthanasia. All rabbits were injected intravenously with either saline or alendronate (7.5 μg/kg) once a week. Each group had 18 rabbits, six in each group being killed at three, six and 12 weeks post-operatively. Alendronate administration suppressed the resorption of the implants. Additionally, the mineral densities of newly formed bone in the alendronate-treated groups were lower than those in the control group at 12 weeks post-operatively. Interestingly, the number of osteoclasts attached to the implant correlated with the extent of bone formation at three weeks. In conclusion, the systemic administration of alendronate in our rabbit model at a dose-for-weight equivalent to the clinical dose used in the treatment of osteoporosis in Japan affected the mineral density and remodelling of bone tissue in implanted porous HA/Col composites

We report the use of porous metal acetabular revision shells in the treatment of contained bone loss. The outcomes of 53 patients with ≤ 50% acetabular bleeding host bone contact were compared with a control group of 49 patients with > 50% to 85% bleeding host bone contact. All patients were treated with the same type of trabecular metal acetabular revision shell. The mean age at revision was 62.4 years (42 to 80) and the mean follow-up of both groups was 72.4 months (60 to 102). Clinical, radiological and functional outcomes were assessed. There were four (7.5%) mechanical failures in the ≤ 50% host bone contact group and no failures in the > 50% host bone contact group (p = 0.068). Out of both groups combined there were four infections (3.9%) and five recurrent dislocations (4.9%) with a stable acetabular component construct that were revised to a constrained liner. Given the complexity of the reconstructive challenge, porous metal revision acetabular shells show acceptable failure rates at five to ten years’ follow-up in the setting of significant contained bone defects. This favourable outcome might be due to the improved initial stability achieved by a high coefficient of friction between the acetabular implant and the host bone, and the high porosity, which affords good bone ingrowth

Aternatives to autogenous bone graft for spinal fusion have been investigated for many years. It has been shown that osteoconductive materials alone do not give a rate of fusion which is comparable to that of autogenous bone graft. We analysed the effectiveness of porous ceramic loaded with cultured mesenchymal stem cells as a new graft material for spinal fusion in an animal model. Posterolateral fusion was carried out at the L4/L5 level in 40 White New Zealand rabbits using one of the following graft materials: porous ceramic granules plus cultured mesenchymal stem cells (group I); ceramic granules plus fresh autogenous bone marrow (group II); ceramic granules alone (group III); and autogenous bone graft (group IV). The animals were killed eight weeks after surgery and the spines were evaluated radiographically, by a manual palpation test and by histological analysis. The rate of fusion was significantly higher in group I compared with group III and higher, but not significantly, in group I compared with groups II and IV. In group I histological analysis showed newly formed bone in contact with the implanted granules and highly cellular bone marrow between the newly formed trabecular bone. In group II, thin trabeculae of newly formed bone were present in the peripheral portion of the fusion mass. In group III, there was a reduced mount of newly formed bone and abundant fibrous tissue. In group IV, there were thin trabeculae of newly formed bone close to the decorticated transverse processes and dead trabecular bone in the central portion of the fusion mass. In vitro cultured mesenchymal stem cells may be loaded into porous ceramic to make a graft material for spinal fusion which appears to be more effective than porous ceramic alone. Further studies are needed to investigate the medium- to long-term results of this procedure, its feasibility in the clinical setting and the most appropriate carrier for mesenchymal stem cells

In a single-blind, randomised series of knee replacements in 116 patients, we used radiostereometric analysis (RSA) to measure micromotion in three types of tibial implant fixation for two years after knee replacement. We compared hydroxyapatite-augmented porous coating, porous coating, and cemented fixation of the same design of tibial component. At one to two years, porous-coated implants migrated at a statistically significantly higher rate than hydroxyapatite-augmented or cemented implants. There was no significant difference between hydroxyapatite-coated and cemented implants. We conclude that hydroxyapatite augmentation may offer a clinically relevant advantage over a simple porous coating for tibial component fixation, but is no better than cemented fixation

We have studied the characteristics of bone ingrowth of a new porous tantalum biomaterial in a simple transcortical canine model using cylindrical implants 5 × 10 mm in size. The material was 75% to 80% porous by volume and had a repeating arrangement of slender interconnecting struts which formed a regular array of dodecahedron-shaped pores. We performed histological studies on two types of material, one with a smaller pore size averaging 430 μm at 4, 16 and 52 weeks and the other with a larger pore size averaging 650 μm at 2, 3, 4, 16 and 52 weeks. Mechanical push-out tests at 4 and 16 weeks were used to assess the shear strength of the bone-implant interface on implants of the smaller pore size. The extent of filling of the pores of the tantalum material with new bone increased from 13% at two weeks to between 42% and 53% at four weeks. By 16 and 52 weeks the average extent of bone ingrowth ranged from 63% to 80%. The tissue response to the small and large pore sizes was similar, with regions of contact between bone and implant increasing with time and with evidence of Haversian remodelling within the pores at later periods. Mechanical tests at four weeks indicated a minimum shear fixation strength of 18.5 MPa, substantially higher than has been obtained with other porous materials with less volumetric porosity. This porous tantalum biomaterial has desirable characteristics for bone ingrowth; further studies are warranted to ascertain its potential for clinical reconstructive orthopaedics

We investigated the early results of modular porous metal components used in 23 acetabular reconstructions associated with major bone loss. The series included seven men and 15 women with a mean age of 67 years (38 to 81), who had undergone a mean of two previous revisions (1 to 7). Based on Paprosky’s classification, there were 17 type 3A and six type 3B defects. Pelvic discontinuity was noted in one case. Augments were used in 21 hips to support the shell and an acetabular component-cage construct was implanted in one case. At a mean follow-up of 41 months (24 to 62), 22 components remained well fixed. Two patients required rerevision of the liners for prosthetic joint instability. Clinically, the mean Harris Hip Score improved from 43.0 pre-operatively (14 to 86) to 75.7 post-operatively (53 to 100). The mean pre-operative Merle d’Aubigné score was 8.2 (3 to 15) and improved to a mean of 13.7 (11 to 18) post-operatively. These short-term results suggest that modular porous metal components are a viable option in the reconstruction of Paprosky type 3 acetabular defects. More data are needed to determine whether the system yields greater long-term success than more traditional methods, such as reconstruction cages and structural allografts

We used radiostereometric analysis to compare wear rates between uncemented porous sockets and cemented all-polyethylene sockets in a series of 102 hips randomised for either a Harris-Galante or a Charnley cup. Wear was evaluated in 95 hips at a mean of five years (2 to 7). All hips had a cemented, 22 mm head mono-bloc Charnley stem. The mean annual wear rate was 0.09 mm in the Charnley sockets and 0.10 mm in the Harris-Galante sockets, with no statistically significant differences in wear, migration or rotation. We conclude that, up to five years, the wear characteristics of the modular and porous Harris-Galante socket resemble that of the Charnley socket

Aims. It may not be possible to undertake revision total hip arthroplasty (THA) in the presence of massive loss of acetabular bone stock using standard cementless hemispherical acetabular components and metal augments, as satisfactory stability cannot always be achieved. We aimed to study the outcome using a reconstruction cage and a porous metal augment in these patients. Patients and Methods. A total of 22 acetabular revisions in 19 patients were performed using a combination of a reconstruction cage and porous metal augments. The augments were used in place of structural allografts. The mean age of the patients at the time of surgery was 70 years (27 to 85) and the mean follow-up was 39 months (27 to 58). The mean number of previous THAs was 1.9 (1 to 3). All patients had segmental defects involving more than 50% of the acetabulum and seven hips had an associated pelvic discontinuity. . Results. Three failures were observed in two hips, both of which had undergone a previous resection of a tumour affecting the acetabulum. Other complications included a late arterial injury, a sciatic nerve palsy, a dislocation treated with a femoral revision, a deep infection treated with irrigation and debridement and a fracture of the greater trochanter treated conservatively. The mean Oxford Hip Score significantly increased from 13.9 (2 to 23) to 28.7 (13 to 38) (p < 0.00001). The mean vertical distance between the centre of rotation of the hip and its normal location decreased from 30 mm to 10 mm. Conclusions. Acceptable early survivorship can be achieved using this novel technique, but it may be unsuitable for use in patients who have previously undergone the resection of a tumour involving the acetabulum. Cite this article: Bone Joint J 2017;99-B:607–13

We have developed a new drug delivery system using porous apatite-wollastonite glass ceramic (A-W GC) to treat osteomyelitis. A-W GC (porosity, 70% and 20% to 30%), or porous hydroxyapatite (HA) blocks (porosity 35% to 48%) used as controls, were soaked in mixtures of two antibiotics, isepamicin sulphate (ISP) and cefmetazole (CMZ) under high vacuum. We evaluated the release concentrations of the antibiotics from the blocks. The bactericidal concentration of ISP from A-W GC was maintained for more than 42 days, but that from HA decreased to below the detection limit after 28 days. The concentrations of CMZ from both materials were lower than those of ISP. An in vivo study using rabbit femora showed that an osseous concentration of ISP was maintained at eight weeks after implantation. Osteoconduction of the A-W GC block was good. Four patients with infected hip arthroplasties and one with osteomyelitis of the tibia have been treated with the new delivery system with excellent results

The effect of zoledronic acid on bone ingrowth was examined in an animal model in which porous tantalum implants were placed bilaterally within the ulnae of seven dogs. Zoledronic acid in saline was administered via a single post-operative intravenous injection at a dose of 0.1 mg/kg. The ulnae were harvested six weeks after surgery. Undecalcified transverse histological sections of the implant-bone interfaces were imaged with backscattered scanning electron microscopy and the percentage of available pore space that was filled with new bone was calculated. The mean extent of bone ingrowth was 6.6% for the control implants and 12.2% for the zoledronic acid-treated implants, an absolute difference of 5.6% (95% confidence interval, 1.2 to 10.1) and a relative difference of 85% which was statistically significant. Individual islands of new bone formation within the implant pores were similar in number in both groups but were 69% larger in the zoledronic acid-treated group. The bisphosphonate zoledronic acid should be further investigated for use in accelerating or enhancing the biological fixation of implants to bone

A total of 20 patients with a depressed fracture of the lateral tibial plateau (Schatzker II or III) who would undergo open reduction and internal fixation were randomised to have the metaphyseal void in the bone filled with either porous titanium granules or autograft bone. Radiographs were undertaken within one week, after six weeks, three months, six months, and after 12 months. The primary outcome measure was recurrent depression of the joint surface: a secondary outcome was the duration of surgery. The risk of recurrent depression of the joint surface was lower (p < 0.001) and the operating time less (p < 0.002) when titanium granules were used. The indication is that it is therefore beneficial to use porous titanium granules than autograft bone to fill the void created by reducing a depressed fracture of the lateral tibial plateau. There is no donor site morbidity, the operating time is shorter and the risk of recurrent depression of the articular surface is less. . Cite this article: Bone Joint J 2015; 97-B:836–41

Aims

The aim of this study was to compare the biomechanical models of two frequently used techniques for reconstructing severe acetabular defects with pelvic discontinuity in revision total hip arthroplasty (THA) – the Trabecular Metal Acetabular Revision System (TMARS) and custom triflange acetabular components (CTACs) – using virtual modelling.

Ceramics have many properties which might make them suitable alternatives to bone grafts. This present study was done to find a suitable biodegradable porous ceramic for human bone replacement. Three different porous ceramics (calcium aluminate, calcium hydroxyapatite and tricalcium phosphate), with interlinked pores of two size ranges (150 to 210 micron), were implanted into the skulls of rats and rabbits for up to six months; the interaction with surrounding bone, which is virtually devoid of bone marrow, was then assessed. The ceramics caused no adverse biological response. Tissue ingrowth into pores throughout the implant was seen in all three types and in both pore sizes of ceramic, but the density of the penetrating tissue was far less for calcium aluminate than for calcium hydroxyapatite or tricalcium phosphate. For each type of ceramic, the soft-tissue ingrowth was more dense with the larger pore size, and with a longer period of implantation. Bone ingrowth was not usually seen within the pores of any ceramic. There were no differences in the histological findings between the rats and the rabbits. The results demonstrate that it is possible to produce ceramic materials with a porous structure which allows ingrowth of tissue and biological fluids

We have investigated the effectiveness of the transplantation of bone-marrow-derived mononuclear cells (BMMNCs) with interconnected porous calcium hydroxyapatite (IP-CHA) on early bone repair for osteonecrosis of the femoral head. We studied 22 patients (30 hips) who had osteonecrosis with a minimum follow-up of one year after implantation of BMMNCs. The mean age at surgery was 41 years (18 to 64) and the mean period of follow-up was 29 months (19 to 48). In a control group, cell-free IP-CHA was implanted into a further eight patients (9 hips) with osteonecrosis of the femoral head and the outcomes were compared. A reduction in the size of the osteonecrotic lesion was observed subsequent to hypertrophy of the bone in the transition zone in the BMMNC group. In three patients in the treatment group progression to extensive collapse was detected. In the control group subtle bone hypertrophy was observed, but severe collapse of the femoral head occurred in six of eight hips. In this limited study the implantation of BMMNCs and IP-CHA appears to confer benefit in the repair of osteonecrosis and in the prevention of collapse

Aims. Vitamin E-diffused, highly crosslinked polyethylene (VEPE) and porous titanium-coated (PTC) shells were introduced in total hip arthroplasty (THA) to reduce the risk of aseptic loosening. The purpose of this study was: 1) to compare the wear properties of VEPE to moderately crosslinked polyethylene; 2) to assess the stability of PTC shells; and 3) to report their clinical outcomes at seven years. Patients and Methods. A total of 89 patients were enrolled into a prospective study. All patients received a PTC shell and were randomized to receive a VEPE liner (n = 44) or a moderately crosslinked polyethylene (ModXLPE) liner (n = 45). Radiostereometric analysis (RSA) was used to measure polyethylene wear and component migration. Differences in wear were assessed while adjusting for body mass index, activity level, acetabular inclination, anteversion, and head size. Plain radiographs were assessed for radiolucency and patient-reported outcome measures (PROMs) were administered at each follow-up. Results. In total, 73 patients (82%) completed the seven-year visit. Mean seven-year linear proximal penetration was -0.07 mm (. sd. 0.16) and 0.00 mm (. sd. 0.22) for the VEPE and ModXLPE cohorts, respectively (p = 0.116). PROMs (p = 0.310 to 0.807) and radiolucency incidence (p = 0.330) were not different between the polyethylene cohorts. The mean proximal shell migration rate was 0.04 mm per year (. sd. 0.09). At seven years, patients with radiolucency (34%) demonstrated greater migration (mean difference: 0.6 mm (. sd. 0.2); p < 0.001). PROMs were lower for patients with radiolucency and greater proximal migration (p = 0.009 to p = 0.045). No implants were revised for aseptic loosening. Conclusion. This is the first randomized controlled trial to report seven-year RSA results for VEPE. All wear rates were below the previously reported osteolysis threshold (0.1 mm per year). PTC shells demonstrated acceptable primary stability through seven years, as indicated by low migration and lack of aseptic loosening. However, patients with acetabular radiolucency were associated with higher shell migration and lower PROM scores. Cite this article: Bone Joint J 2019;101-B:760–767

We have evaluated the use of a synthetic porous ceramic (Triosite) as a substitute for bone graft in posterior spinal fusion for idiopathic scoliosis. In a prospective, randomised study 341 patients at five hospitals in the UK and France were randomly allocated either to autograft from the iliac crest or rib segments (171) or to receive Triosite blocks (170). All patients were assessed after operation and at 3, 6, 12 and 18 months. The two groups were similar with regard to all demographic and baseline variables, but the 184 treated in France (54%) had Cotrel-Dubouset instrumentation and the 157 treated in the UK usually had Harrington-Luque implants. In the Triosite group the average Cobb angle of the upper curve was 56°, corrected to 24° (57%). At 18 months, the average was 26° (3% loss). In the autograft group the average preoperative upper curve of 53° was corrected to 21° (60%). At 18 months the mean curve was 25° (8% loss). Pain levels after operation were similar in the two groups, being mild in most cases. In the Triosite group only three patients had problems of wound healing, but in the autograft group, 14 patients had delayed healing, infection or haematoma in the spinal wound. In addition, 15 autograft patients had pain at the donor site at three months. Seven had infections, two had haematoma and four had delayed healing. The haematological and serum biochemistry results showed no abnormal trends and no significant differences between the groups. There were no adverse events related to the graft material and no evidence of allergenicity. Our results suggest that Triosite synthetic porous ceramic is a safe and effective substitute for autograft in these patients. Histological findings on biopsy indicate that Triosite provides a favourable scaffolding for the formation of new bone and is gradually incorporated into the fusion mass

We reviewed 40 cementless Porous Coated Anatomic knee replacements in 34 consecutive patients. The average follow-up was 12.9 months (range 6 to 36 months). At review, loose beads were identified in 23 knees, in 11 on the femoral side and in 16 on the tibial side (in five knees on both sides). One loose bead was adjacent to the patella. In four knees there were intra-articular beads. Radiolucent lines at the interface between bone and prosthesis were seen in 19 knees, in six on the femoral side and in 16 on the tibial side (in three knees on both sides). In relation to the tibial component loose beads were associated with a radiolucent line in all except one case. Progressive loosening with an increasing number of loose beads was seen in three knees. At this early stage of follow-up there was no correlation between the clinical results and the presence of loose beads

The aim of this prospective randomised study was to compare the clinical and radiological results of a cemented all-polyethylene Ultima acetabular component with those of a cementless porous-coated acetabular component (PFC) following total hip replacement (THR). A total of 287 patients received either a polyethylene acetabular component (group A) or a cobalt–chromium porous-coated component (group B) with an identical cemented femoral component and 28 mm cobalt-chromium head, thus making it the largest study of its type. Patients were evaluated radiologically and clinically using the Harris hip score (HHS). Group A comprised 183 patients (73 male, 110 female) with a mean age of 71.3 years (55 to 89). Group B comprised 104 patients (48 male, 56 female) with a mean age of 69.8 years (56 to 89). A total of 16 patients (13 in Group A, three in Group B) did not have post-operative data for analysis. The mean follow-up in group A was 7.52 years (0.4 to 15.0) and in Group B 7.87 years (0.5 to 14.0).

At final follow-up the mean HHS was similar between groups A and B (74.5 (25 to 100) and 78.0 (37 to 100), respectively; p = 0.068). The total number of revisions for any cause was 28, 17 of which were in group A and 11 in group B. The ten-year survivorship was 86.8% (95% confidence interval (CI) 78.4 to 92.1) and 89.2% (95% CI 78.3 to 94.8) for groups A and B, respectively (log-rank p-value = 0.938). A total of 20 cemented and two cementless acetabular components had evidence of acetabular radiolucencies or acetabular component migration at last follow-up (p = 0.001).

These results indicate that patients with a cemented all-polyethylene and cementless porous-coated polyethylene lined acetabular component have similar long-term clinical outcomes.

In rabbits and goats, test implants with a porous surface of two layers of Tl-6A;-4V beads were examined at intervals for bond strength with bone. Half of the implants were coated with hydroxyapatite by plasma spray. The bonding strength with bone in the coated specimens was about four times greater than that of the uncoated specimens at two weeks, and twice as strong at six weeks. Twelve weeks after implantation, the strengths were similar. The hydroxyapatite coating of the beads provided earlier and stronger fixation

Animal experiments are reported in which porous titanium plugs were used to secure a prosthetic tendon to bone. The plugs remained fixed under functional load and were colonised by healthy lamellar bone. These results suggest that such plugs form reliable anchorages

Aims

The use of trabecular metal (TM) shells supported by augments has provided good mid-term results after revision total hip arthroplasty (THA) in patients with a bony defect of the acetabulum. The aim of this study was to assess the long-term implant survivorship and radiological and clinical outcomes after acetabular revision using this technique.

Between January 1998 and December 1998, 82 consecutive patients (86 hips) underwent total hip arthroplasty using a trabecular metal monoblock acetabular component. All patients had a clinical and radiological follow-up evaluation at six, 12 and 24 weeks, 12 months, and then annually thereafter. On the initial post-operative radiograph 25 hips had a gap between the outer surface of the component and the acetabular host bed which ranged from 1 to 5 mm. All patients were followed up clinically and radiologically for a mean of 7.3 years (7 to 7.5). The 25 hips with the 1 to 5 mm gaps were studied for component migration at two years using the Einzel-Bild-Roentgen-Analyse (EBRA) digital measurement method. At 24 weeks all the post-operative gaps were filled with bone and no acetabular component had migrated. The radiographic outcome of all 86 components showed no radiolucent lines and no evidence of lysis. No acetabular implant was revised. There were no dislocations or other complications. The bridging of the interface gaps (up to 5 mm) by the trabecular metal monoblock acetabular component indicates the strong osteoconductive, and possibly osteoinductive, properties of trabecular metal.

The clinical and radiological results of 50 consecutive acetabular reconstructions in 48 patients using impaction grafting have been retrospectively reviewed. A 1:1 mixture of frozen, ground irradiated bone graft and Apapore 60, a synthetic bone graft substitute, was used in all cases. There were 13 complex primary and 37 revision procedures with a mean follow-up of five years (3.4 to 7.6). The clinical survival rate was 100%, with improvements in the mean Harris Hip Scores for pain and function. Radiologically, 30 acetabular grafts showed evidence of incorporation, ten had radiolucent lines and two acetabular components migrated initially before stabilising.

Acetabular reconstruction in both primary and revision surgery using a 1:1 mixture of frozen, ground, irriadiated bone and Apapore 60 appears to be a reliable method of managing acetabular defects. Longer follow-up will be required to establish whether this technique is as effective as using fresh-frozen allograft.

Aims. The aim of this study was to compare the ability of tantalum, 3D porous titanium, antibiotic-loaded bone cement, and smooth titanium alloy to inhibit staphylococci in an in vitro environment, based on the evaluation of the zone of inhibition (ZOI). The hypothesis was that there would be no significant difference in the inhibition of methicillin-sensitive or methicillin-resistant Staphylococcus aureus (MSSA/MRSA) between the two groups. Methods. A total of 30 beads made of three different materials (tantalum/3D porous titanium and smooth titanium alloy) were bathed for one hour in a solution of 1 g vancomycin in 20 ml of sterile water for injection (bath concentration: 50 mg/mL). Ten 1 cm. 3. cylinders of antibiotic-loaded cement were also created by mixing standard surgical cement with 1 g of vancomycin in standardized sterile moulds. The cylinders were then placed on agar plates inoculated with MSSA and MRSA. The ZOIs were measured each day and the cylinders were transferred onto a new inoculated plate. Results. For MSSA and MRSA, no inhibitory effect was found in the control group, and antibiotic-loaded smooth titanium alloy beads showed a short inhibitory effect until day 2. For MSSA, both tantalum and 3D porous titanium beads showed significantly larger mean ZOIs than cement beads (all p < 0.01) each day until day 7 for tantalum and until day 3 for 3D porous titanium. After six days, antibiotic-loaded cement had significantly larger mean ZOIs than the 3D porous titanium (p = 0.027), but no significant difference was found with tantalum (p = 0.082). For MRSA, both tantalum and 3D porous titanium beads had significantly larger mean ZOIs than antibiotic-loaded cement each day until day 6 for tantalum (all p < 0.01) and until day 3 for 3D porous titanium (all p < 0.04). Antibiotic-loaded cement had significantly larger mean ZOIs than tantalum and 3D porous titanium from day 7 to 9 (all p < 0.042). Conclusion. These results show that porous metal implants can deliver local antibiotics over slightly varying time frames based on in vitro analysis. Cite this article: Bone Joint J 2020;102-B(6 Supple A):158–162

Aims. The aims of this study were to determine the success of a reconstruction algorithm used in major acetabular bone loss, and to further define the indications for custom-made implants in major acetabular bone loss. Methods. We reviewed a consecutive series of Paprosky type III acetabular defects treated according to a reconstruction algorithm. IIIA defects were planned to use a superior augment and hemispherical acetabular component. IIIB defects were planned to receive either a hemispherical acetabular component plus augments, a cup-cage reconstruction, or a custom-made implant. We used national digital health records and registry reports to identify any reoperation or re-revision procedure and Oxford Hip Score (OHS) for patient-reported outcomes. Implant survival was determined via Kaplan-Meier analysis. Results. A total of 105 procedures were carried out in 100 patients (five bilateral) with a mean age of 73 years (42 to 94). In the IIIA defects treated, 72.0% (36 of 50) required a porous metal augment; the remaining 14 patients were treated with a hemispherical acetabular component alone. In the IIIB defects, 63.6% (35 of 55) underwent reconstruction as planned with 20 patients who actually required a hemispherical acetabular component alone. At mean follow-up of 7.6 years, survival was 94.3% (95% confidence interval 97.4 to 88.1) for all-cause revision and the overall dislocation rate was 3.8% (4 of 105). There was no difference observed in survival between type IIIA and type IIIB defects and whether a hemispherical implant alone was used for the reconstruction or not. The mean gain in OHS was 16 points. Custom-made implants were only used in six cases, in patients with either a mega-defect in which the anteroposterior diameter > 80 mm, complex pelvic discontinuity, and massive bone loss in a small pelvis. Conclusion. Our findings suggest that a reconstruction algorithm can provide a successful approach to reconstruction in major acetabular bone loss. The use of custom implants has been defined in this series and accounts for < 5% of cases. Cite this article: Bone Joint J 2024;106-B(5 Supple B):47–53

Aims. The aims of this study were to compare the mean duration of antibiotic release and the mean zone of inhibition between vancomycin-loaded porous tantalum cylinders and antibiotic-loaded bone cement at intervals, and to evaluate potential intrinsic antimicrobial properties of tantalum in an in vitro medium environment against methicillin-sensitive Staphylococcus aureus (MSSA). Materials and Methods. Ten porous tantalum cylinders and ten cylinders of cement were used. The tantalum cylinders were impregnated with vancomycin, which was also added during preparation of the cylinders of cement. The cylinders were then placed on agar plates inoculated with MSSA. The diameter of the inhibition zone was measured each day, and the cylinders were transferred to a new inoculated plate. Inhibition zones were measured with a Vernier caliper and using an automated computed evaluation, and the intra- and interobserver reproducibility were measured. The mean inhibition zones between the two groups were compared with Wilcoxon’s test. Results. MSSA was inhibited for 12 days by the tantalum cylinders and for nine days by the cement cylinders. At day one, the mean zone of inhibition was 28.6 mm for the tantalum and 19.8 mm for the cement group (p < 0.001). At day ten, the mean zone of inhibition was 3.8 mm for the tantalum and 0 mm for the cement group (p < 0.001). The porous tantalum cylinders soaked only with phosphate buffered solution showed no zone of inhibition. Conclusion. Compared with cement, tantalum could release antibiotics for longer. Further studies should assess the advantages of using antibiotic-loaded porous tantalum implants at revision arthroplasty. Cite this article: Bone Joint J 2019;101-B:848–851

Aims. Porous metaphyseal cones can be used for fixation in revision total knee arthroplasty (rTKA) and complex TKAs. This metaphyseal fixation has led to some surgeons using shorter cemented stems instead of diaphyseal engaging cementless stems with a potential benefit of ease of obtaining proper alignment without being beholden to the diaphysis. The purpose of this study was to evaluate short term clinical and radiographic outcomes of a series of TKA cases performed using 3D-printed metaphyseal cones. Methods. A retrospective review of 86 rTKAs and nine complex primary TKAs, with an average age of 63.2 years (SD 8.2) and BMI of 34.0 kg/m. 2. (SD 8.7), in which metaphyseal cones were used for both femoral and tibial fixation were compared for their knee alignment based on the type of stem used. Overall, 22 knees had cementless stems on both sides, 52 had cemented stems on both sides, and 15 had mixed stems. Postoperative long-standing radiographs were evaluated for coronal and sagittal plane alignment. Adjusted logistic regression models were run to assess malalignment hip-knee-ankle (HKA) alignment beyond ± 3° and sagittal alignment of the tibial and femoral components ± 3° by stem type. Results. No patients had a revision of a cone due to aseptic loosening; however, two had revision surgery due to infection. In all, 26 (27%) patients had HKA malalignment; nine (9.5%) patients had sagittal plane malalignment, five (5.6%) of the tibia, and four (10.8%) of the femur. After adjusting for age, sex, and BMI, there was a significantly increased risk for malalignment when a cone was used and both the femur and tibia had cementless compared to cemented stems (odds ratio 3.19, 95% confidence interval 1.01 to 10.05). Conclusion. Porous 3D-printed cones provide excellent metaphyseal fixation. However, these central cones make the use of offset couplers difficult and may generate malalignment with cementless stems. We found 3.19-times higher odds of malalignment in our TKAs performed with metaphyseal cones and both femoral and tibial cementless stems. Cite this article: Bone Joint J 2021;103-B(6 Supple A):150–157

Aims. Our intention was to investigate if the highly porous biological fixation surfaces of a new 3D-printed total knee arthroplasty (TKA) achieved adequate fixation of the tibial and patellar components to the underlying bone. Patients and Methods. A total of 29 patients undergoing primary TKA consented to participate in this prospective cohort study. All patients received a highly porous tibial baseplate and metal-backed patella. Patient-reported outcomes measures were recorded and implant migration was assessed using radiostereometric analysis. Results. Patient function significantly improved by three months postoperatively (p < 0.001). Mean difference in maximum total point motion between 12 and 24 months was 0.021 mm (-0.265 to 0.572) for the tibial implant and 0.089 mm (-0.337 to 0.758) for the patellar implant. The rate of tibial and patellar migration was largest over the first six postoperative weeks, with no changes in mean tibia migration occurring after six months, and no changes in mean patellar migration occurring after six weeks. One patellar component showed a rapid rate of migration between 12 and 24 months. Conclusion. Biological fixation appears to occur reliably on the highly porous implant surface of the tibial baseplate and metal-backed patellar component. Rapid migration after 12 months was measured for one patellar component. Further investigation is required to assess the long-term stability of the 3D-printed components and to determine if the high-migrating components achieve fixation. Cite this article: Bone Joint J 2019;101-B(7 Supple C):40–47

Aims. Tibial cones are often utilized in revision total knee arthroplasty (TKA) with metaphyseal defects. Because there are few studies evaluating mid-term outcomes with a sufficient cohort, the purpose of this study was to evaluate tibial cone survival and complications in revision TKAs with tibial cones at minimum follow-up of five years. Methods. A retrospective review was completed from September 2006 to March 2015, evaluating 67 revision TKAs (64 patients) that received one specific porous tibial cone during revision TKA. The final cohort was composed of 62 knees (59 patients) with five years of clinical follow-up or reoperation. The mean clinical follow-up of the TKAs with minimum five-year clinical follow-up was 7.6 years (5.0 to 13.3). Survivorship analysis was performed with the endpoints of tibial cone revision for aseptic loosening, tibial cone revision for any reason, and reoperation. We also evaluated periprosthetic joint infection (PJI), risk factors for failure, and performed a radiological review. Results. The rate of cone revision for aseptic loosening was 6.5%, with an eight-year survival of 95%. Significant bone loss (Anderson Orthopaedic Research Institute grade 3) was associated with cone revision for aseptic loosening (p = 0.002). The rate of cone revision for any reason was 17.7%, with an eight-year survival of 84%. Sixteen percent of knees developed PJI following revision. A pre-revision diagnosis of reimplantation as part of a two-stage exchange protocol for infection was associated with both PJI (p < 0.001) and tibial cone revision (p = 0.001). Conclusion. Mid-term results of tibial cones showed a survivorship free of cone revision for aseptic loosening of 95%. Patients with significant bone loss were more likely to have re-revision for tibial cone failure. Infection was common, and patients receiving cones at reimplantation were more likely to develop PJI and undergo cone revision. Cite this article: Bone Joint J 2021;103-B(6 Supple A):158–164

Aims. Although bone cement is the primary mode of fixation in total knee arthroplasty (TKA), cementless fixation is gaining interest as it has the potential of achieving lasting biological fixation. By 3D printing an implant, highly porous structures can be manufactured, promoting osseointegration into the implant to prevent aseptic loosening. This study compares the migration of cementless, 3D-printed TKA to cemented TKA of a similar design up to two years of follow-up using radiostereometric analysis (RSA) known for its ability to predict aseptic loosening. Methods. A total of 72 patients were randomized to either cementless 3D-printed or a cemented cruciate retaining TKA. RSA and clinical scores were evaluated at baseline and postoperatively at three, 12, and 24 months. A mixed model was used to analyze the repeated measurements. Results. The mean maximum total point motion (MTPM) at three, 12, and 24 months was 0.33 mm (95% confidence interval (CI) 0.25 to 0.42), 0.42 mm (95% CI 0.33 to 0.51), and 0.47 mm (95% CI 0.38 to 0.57) respectively in the cemented group, versus 0.52 mm (95% CI 0.43 to 0.63), 0.62 mm (95% CI 0.52 to 0.73), and 0.64 mm (95% CI 0.53 to 0.75) in the cementless group (p = 0.003). However, using three months as baseline, no difference in mean migration between groups was found (p = 0.497). Three implants in the cemented group showed a > 0.2 mm increase in MTPM between one and two years of follow-up. In the cementless group, one implant was revised due to pain and progressive migration, and one patient had a liner-exchange due to a deep infection. Conclusion. The cementless TKA migrated more than the cemented TKA in the first two-year period. This difference was mainly due to a higher initial migration of the cementless TKA in the first three postoperative months after which stabilization was observed in all but one malaligned and early revised TKA. Whether the biological fixation of the cementless implants will result in an increased long-term survivorship requires a longer follow-up. Cite this article: Bone Joint J 2020;102-B(8):1016–1024

Aims. Metaphyseal fixation during revision total knee arthroplasty (TKA) is important, but potentially difficult when using historical designs of cone. Material and manufacturing innovations have improved the size and shape of the cones which are available, and simplified the required bone preparation. In a large series, we assessed the implant survivorship, radiological results, and clinical outcomes of new porous 3D-printed titanium metaphyseal cones featuring a reamer-based system. Methods. We reviewed 142 revision TKAs in 139 patients using 202 cones (134 tibial, 68 femoral) which were undertaken between 2015 and 2016. A total of 60 involved tibial and femoral cones. Most cones (149 of 202; 74%) were used for Type 2B or 3 bone loss. The mean age of the patients was 66 years (44 to 88), and 76 (55 %) were female. The mean body mass index (BMI) was 34 kg/m. 2. (18 to 60). The patients had a mean of 2.4 (1 to 8) previous operations on the knee, and 68 (48%) had a history of prosthetic infection. The mean follow-up was 2.4 years (2 to 3.6). Results. Survivorship free of cone revision for aseptic loosening was 100% and survivorship free of any cone revision was 98%. Survivorships free of any revision and any reoperation were 90% and 83%, respectively. Five cones were revised: three for infection, one for periprosthetic fracture, and one for aseptic tibial loosening. Radiologically, three unrevised femoral cones appeared loose in the presence of hinged implants, while the remaining cones appeared stable. All cases of cone loosening occurred in patients with Type 2B or 3 defects. The mean Knee Society score (KSS) improved significantly from 50 (0 to 94) preoperatively to 87 (72 to 94) (p < 0.001). Three intraoperative fractures with cone impaction (two femoral, one tibial) healed uneventfully. Conclusion. Novel 3D-printed titanium cones, with a reamer-based system, yielded excellent early survivorship and few complications in patients with severe bone loss undergoing difficult revision TKA. The diversity of cone options, relative ease of preparation, and outcomes rivalling those of previous designs of cone support their continued use. Cite this article: Bone Joint J 2020;102-B(6 Supple A):107–115

Aims. Reconstruction of the acetabulum after resection of a periacetabular malignancy is technically challenging and many different techniques have been used with varying success. Our aim was to prepare a systematic review of the literature dealing with these techniques in order to clarify the management, the rate of complications and the outcomes. Patients and Methods. A search of PubMed and MEDLINE was conducted for English language articles published between January 1990 and February 2017 with combinations of key search terms to identify studies dealing with periacetabular resection with reconstruction in patients with a malignancy. Studies in English that reported radiographic or clinical outcomes were included. Data collected from each study included: the number and type of reconstructions, the pathological diagnosis of the lesions, the mean age and follow-up, gender distribution, implant survivorship, complications, functional outcome, and mortality. The results from individual studies were combined for the general analysis, and then grouped according to the type of reconstruction. . Results. A total of 57 studies met the inclusion criteria and included 1700 patients. Most lesions were metastatic (41%), followed by chondrosarcoma (29%), osteosarcoma (10%), Ewing’s sarcoma (7%), and multiple myeloma (2%). The techniques of reconstruction were divided into seven types for analysis: those involving a Harrington reconstruction, a saddle prosthesis, an allograft and allograft prosthesis composite, a pasteurised autograft, a porous tantalum implant, a custom-made prosthesis and a modular hemipelvic reconstruction. The rate of complications was 50%, with infection (14%) and instability (8%) being the most common. Mortality data were available for 1427 patients (84%); 50% had died of disease progression, 23% were alive with disease, and 27% had no evidence of disease at a mean follow-up of 3.4 years (0 to 34). . Conclusion. Both the rate of complications and mortality are high following resection of oncological periacetabular lesions and reconstruction. Many types of reconstruction have been used with unique challenges and complications for each technique. Newer prostheses, including custom-made prostheses and porous tantalum implants and augments, have shown promising early functional and radiographic outcomes. . Cite this article: Bone Joint J 2018;100-B(1 Supple A):22–30

Aims. The aim of this study was to compare early functional and health related quality of life outcomes (HRQoL) in patients who have undergone total hip arthroplasty (THA) using a bone conserving short stem femoral component and those in whom a conventional length uncemented component was used. Outcome was assessed using a validated performance based outcome instrument as well as patient reported outcome measures (PROMs). Patients and Methods. We prospectively analysed 33 patients whose THA involved a contemporary proximally porous coated tapered short stem femoral component and 53 patients with a standard conventional femoral component, at a minimum follow-up of two years. The mean follow-up was 31.4 months (24 to 39). Patients with poor proximal femoral bone quality were excluded. The mean age of the patients was 66.6 years (59 to 77) and the mean body mass index was 30.2 kg/m. 2. (24.1 to 41.0). Outcome was assessed using the Oxford Hip Score (OHS) and the University College Hospital (UCH) hip score which is a validated performance based instrument. HRQoL was assessed using the EuroQol 5D (EQ-5D). Results. There were no major peri-operative complications. There was no difference in the mean post-operative OHS, EQ-5D or function subscale of the UCH hip scores between the two groups. The mean pre-operative OHS and EQ-5D scores improved significantly (all p <  0.001). The mean functional component of the UCH hip score at final follow-up was 42.5 and 40.6 in the short stem and conventional stem groups, respectively. There was no statistically significant difference between the groups (p = 0.42). A total of seven patients (21.2%) in the short stem group and nine (16.98%) in the conventional group achieved a ceiling effect using the OHS; none did using the function subscale of the UCH hip score. Conclusion. The proximally porous coated tapered short stem femoral component achieves comparable short-term functional outcomes when compared with a conventional longer stem uncemented femoral component when THA is undertaken in patients with good bone quality. Cite this article: Bone Joint J 2017;99-B(4 Supple B):49–55

A pelvic discontinuity occurs when the superior and inferior parts of the hemi-pelvis are no longer connected, which is difficult to manage when associated with a failed total hip replacement. Chronic pelvic discontinuity is found in 0.9% to 2.1% of hip revision cases with risk factors including severe pelvic bone loss, female gender, prior pelvic radiation and rheumatoid arthritis. Common treatment options include: pelvic plating with allograft, cage reconstruction, custom triflange implants, and porous tantalum implants with modular augments. The optimal technique is dependent upon the degree of the discontinuity, the amount of available bone stock and the likelihood of achieving stable healing between the two segments. A method of treating pelvic discontinuity using porous tantalum components with a distraction technique that achieves both initial stability and subsequent long-term biological fixation is described. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):73–7

Aims. The aim of this study was to assess the effects of transferring patients to a specialized arthroplasty centre between the first and second stages (interstage) of prosthetic joint infection (PJI) of the knee. Patients and Methods. A search of our institutional database was performed to identify patients having undergone two-stage revision total knee arthroplasty (TKA) for PJI. Two cohorts were created: continuous care (CC) and transferred care (TC). Baseline characteristics and outcomes were collected and compared between cohorts. Results. A total of 137 patients were identified: 105 in the CC cohort (56 men, 49 women; mean age 67.9) and 32 in the TC cohort (17 men, 15 women; mean age 67.8 years). PJI organism virulence was greater in the CC cohort (36.2% vs 15.6%; p = 0.030). TC patients had a higher rate of persisting or recurrent infection (53.6% vs 13.4%; p < 0.001), soft-tissue complications (31.3 vs 14.3%; p = 0.030), and reduced requirement for porous metal augments (78.1% vs 94.3%; p = 0.006). Repeat first stage debridement after transfer led to greater need for plastic surgical procedures (58.3% vs 0.0%; p < 0.001). Conclusion. Patient transfer during the interstage of treatment for infected TKA leads to poorer outcomes compared with patients receiving all their treatment at a specialized arthroplasty centre. Cite this article: Bone Joint J 2019;101-B:1087–1092

Aims

Dislocation remains a leading cause of failure following revision total hip arthroplasty (THA). While dual-mobility (DM) bearings have been shown to mitigate this risk, options are limited when retaining or implanting an uncemented shell without modular DM options. In these circumstances, a monoblock DM cup, designed for cementing, can be cemented into an uncemented acetabular shell. The goal of this study was to describe the implant survival, complications, and radiological outcomes of this construct.