Introduction. To evaluate the effect of hydroxyapatite coating, two same shape cementless stems were compared in this randomized control trial study. Methods. Between May 2003 and February 2010, 88 patients had a primary cementless total hip arthroplasty with two different types of cementless stems. Forty-three patients had Proarc stems (P group) (Kyocera Medical, Osaka, Japan), and Forty-five patients had Proarc HA stems (HA group) (Kyocera Medical, Osaka, Japan) which was coated with thin (20 micrometer) hydroxyapatite on Proarc rough porous coating. Gender distribution, average age at surgery, average weight and average follow-up period were same in the two groups. The average follow-up period was 8.5 years (range, 5 to 13 years). The average age at the time of surgery was 63 years. Porous acetabular shells and highly crosslinked polyethylene liners made by Kyocera Medical corporation were implanted into all hips. Stems were implanted with a modified Hardinge surgical approach without trochanteric osteotomy. Harris Hip Score was used for clinical evaluation. Post-op radiographs of these patients were evaluated. Fisher's exact probability test was used for statistical analysis. P values of less than 0.05 were considered to be significant. Results. The mean preoperative score and postoperative score of P group were 39 points and 86 points, respectively. The mean preoperative score and postoperative score of HA group were 46 points and 87 points, respectively. All stems were evaluated as bone-ingrown fixation in both groups. The rate of varus inclination was not different between two groups. The rate of severe stress shielding was not different. Discussion. However hydroxyapatite coating is useful for early fixation, the adverse effect, such as delamination for long-term in vivo situation is questionable. There was no significant difference between P-group and HA group in the present study. Longer follow-up is required to evaluate hydroxyapatite coating

Aim. Treatment principles of chronic osteomyelitis include debridement, clean sampling, excision of dead bone, stabilization, dead space management, soft tissue closure and systemic antibiotic therapy. Dead space management becomes very complicated, if the bone infection is caused by multi-resistant bacteria. The aim of this investigation was to evaluate the effect of a new vancomycin-loaded hydroxyapatite / calcium sulfate composite. *. in the treatment of chronic osteomyelitis (OM) caused by multi-resistant bacteria. Method. From June 2015 to November 2015, 7 patients (4 males, 3 females, average age 52.6y) were treated according to the above mentioned principles using the new vancomycin-loaded hydroxyapatite / calcium sulfate composite. *. Infections were caused by methicillin-resistant Staphylococcus aureus (MRSA), multi-resistant Staphylococcus epidermidis (MRSE) and polymicrobial, vancomycin-sensitive bacteria. We used a two-stage protocol with debridement, excision of bone and external stabilization in the first stage, followed by bone defect reconstruction. To fill the residual bone defects, in 3 patients the new vancomycin-loaded hydroxyapatite / calcium sulfate composite. *. (10mL) was used on its own and in 4 patients combined with 18mL of an unloaded calcium sulfate / hydroxyapatite composite. **. Post-operative follow-up was evaluated clinically and by radiographs and CT scans at 6, 14 and 24 weeks. Results. In 6 of 7 patients rapid control of infection was achieved. Soft tissue reactions and prolonged white wound drainage (caused by calcium sulfate dissolution) was seen in 3 of 7 patients. In 6 of 7 patients recurrence of infection has not been observed so far. Radiographs showed different elution intervals of the radiocontrast agent (Iohexol), depending on anatomical location. Bone remodelling or replacement of the composite by new bone was not uniform in the patients and showed specific radiographic signs. In addition to the so-called „puddle sign“, we found septae, membranes, vacuoles and sometimes arc-like structures. Therefore, we suggest the name “arc-sign” for these formations. Conclusions. During the follow-up of the first 7 patients treated with the unloaded calcium sulfate / hydroxyapatite composite. **. in 6 of 7 cases no recurrence of infection was observed. This is very promising in the difficult situation of bone infections caused by multi-resistant bacteria. Follow-up radiographs and CT-scans showed specific patterns during the resorption of the composite and the formation of new bone, which have not been described in other bone graft substitutes so far. The bone defects are not completely filled yet, but the affected bones are clinically stable and patients can ambulate with full weight bearing

Surgical failure, mainly caused by loosening implants, causes great mental and physical trauma to patients. Improving the physicochemical properties of implants to achieve favourable osseointegration will continue to be the focus of future research. Strontium (Sr), a trace element, is often incorporated into hydroxyapatite (HA) to improve its osteogenic activity. Our previous studies have shown that miR-21 can promote the osteogenic differentiation of mesenchymal stem cells by the PI3K/β-catenin pathway. The aim of this study is to fabricate a SrHA and miR-21 composite coating and it is expected to have a favorable bone healing capability. Ti discs (20 mm diameter and one mm thickness for the in vitro section) and rods (four mm diameter and seven mm length for the in vivo section) were prepared by machining pure Ti. The Ti cylinders were placed in a Teflon-lined stainless-steel autoclave for treating at 150°C for 24 h to form SrHA layer. The miR-21 was encapsulated in nanocapsules. The miR-21 nanocapsules were mixed with CMCS powder to form a gel-like sample and uniformly coated on the SrHA modifed Ti. Osteoblast-like MG63 cells were cultured on SrHA and miR-21 modified Ti, Cell proliferation activity and osteogenesis-related gene expression were evaluated. A bone defect model was established with mature New Zealand to evaluate the osseointegration. Cylindrical holes (four mm in diameter) were created at the distal femur and tibial plateau. Each rabbit was implanted with four of the aforementioned rods (distal femur and tibial plateau of the hind legs). After implantation for one, two and three months, the rabbits were observed by X-ray and scanned using u-CT. Histological and Immunohistochemical analysis were performed to examine the osteogenic markers. A biomechanical push-in test was used to assess the bone-implant bonding strength. Both SrHA nanoparticles with good superhydrophilicity and miR-21 nanocapsules with uniform sizes were distributed evenly on the surface of the Ti. In vitro experiments revealed that the composite coating was beneficial to osteoblast proliferation, differentiation and mineralization. In vivo evaluations demonstrated that this coating could not only promote the expression of angiogenic factor CD31 but also enhance the expression of osteoblastic genes to facilitate angio-osteogenesis. In addition, the composite coating also showed a decreased RANKL expression compared with the miR-21 coating. As a result, the SrHA/miR-21 composite coating promoted new bone formation and mineralization and thus enhanced osseointegration and bone-implant bonding strength. A homogeneous SrHA and miR-21 composite coating was fabricated by generating pure Ti through a hydrothermal process, followed by adhering miR-21 nanocapsules. This coating combined the favorable physicochemical properties of SrHA and miR-21 that synergistically promoted angiogenesis, osteogenesis, osseointegration, bone mineralization and thus bone-implant bonding strength. This study provided a new strategy for surface modification of biomedical implants

Aim. Bone and implant-associated infections caused by microorganisms that grow in biofilm are difficult to treat because of persistence and recurrence. Systemic administration of antibiotics is often inefficient because the poor vascularization of the site of infection. This issue has led to the development of biomaterials capable to locally deliver high doses of therapeutic agents to the injured bone with minimal systemic effects. In this context, calcium sulphate/hydroxyapatite (CS/HA) bone graft substitutes are widely used being safe, osteoconductive and resorbable biomaterials that can be easily enriched with consistent amounts of antibiotics. In this in vitro study, the capability of the eluted antibiotics to select the tested bacterial strains for antibiotic resistance was evaluated to confirm the safe use of the product. Method. S. aureus, S. epidermidis and P. aeruginosa isolated in our Institute from bone and joint infection with different resistance phenotypes were used. 6 × 2.5 mm CS/HA discs were generated by pouring the antibiotic loaded formulations in a mold and were used as a modified disk diffusion test. The resistance selection was evaluated by subculturing cells growing on the edge of the zone of inhibition (ZOI) for seven days. Minimum inhibitory concentrations (MICs) of gentamicin and vancomycin were determined by broth microdilution method before and after the selection of resistance assay. In addition, MICs were assessed after seven day passage on antibiotic free agar plates to evaluate if eventual decrease of antibiotic susceptibility was stable or only transient. Results. Commonly, no adaptation in presence of both CS/HA formulations was observed by analysing ZOI on agar medium. The kinetic of decrease of the ZOI was similar between the strains, with the exception of gentamicin resistant staphylococci in presence of gentamicin loaded CS/HA, which was faster with respect to the susceptible strains. Conclusions. The present study shows that elution of gentamicin and vancomycin from CS/HA bone graft substitutes did not induce a decrease in susceptibility to these antibiotics in an in vitro setting, suggesting the safe use of the product

Introduction. We have investigated middle-term clinical results of total hip arthroplasty (THA) cemented socket with improved technique using hydroxyapatite (HA) granules. IBBC (interfacial bioactive bone cement method, Oonishi) (1) is an excellent technique for augmenting cement-bone fixation in the long term. However, the technique is difficult and there are concerns over some points, such as bleeding control, disturbance of cement intrusion to anchoring holes by granules, difficulty of the uniform granular dispersion to the acetabular bone. To improve the original technique, we have modified IBBC (M-IBBC), and investigated the middle-term clinical results and radiographic changes. Materials and Methods. K-MAX HS-3 THA (Kyocera, Japan), with tapered cemented stem with small collar and all polyethylene cemented socket, was used for THA implants (Fig.1). Basically the third generation cementing technique was used for THA using bone cement. The socket fixation was performed with bone cement (Endurance, DePuy) and HA granules (Ca10(PO4)6(OH)2, Boneceram P; G-2, 0.3–0.6mm in size, Olympus, Japan) (Fig.2). In original IBBC technique, HA granules were dispersed on reamed acetabulum before cementing. In M-IBBC technique, HA granules were attached to bone cement on plastic plate, then inserted to reamed acetabulum and pressurized (Fig.3). 112 hip joints (95 cases) were operated between June 2010 and March 2014, and followed. The average follow-up period was 6.5 years, and average age at operation was 66.5 years. The clinical results were evaluated by Japan Orthopaedic Association Hip Score (JOA score), and X-p findings were evaluated using antero-posterior radiographs. The locations of radiolucent lines were identified according to the zones described by Delee and Charnley for acetabular components, and Zone 1 was divided into two parts, outer Zone 1a and inner Zone 1b. Results and Discussion. Revision was not performed. JOA score improved from 47 to 88. Socket and stem loosening was not observed. X-p findings of sockets demonstrated radiolucent line in Zone 1a/1b/2/3 in 0.9/0/0/0% immediately after the operation, 6.3/1.8/0/0.9% at 2 years postoperatively. After 2 years there was no progressive change, however, improvement of radiolucent line in Zone 1a was observed in two cases after 3 years postoperatively. Accordingly, at 5 years radiolucent line in Zone 1a/1b was observed in 4.4/1.8%. Oonish has reported excellent clinical results of THA with IBBC (1). To easily perform IBBC, we have modified the technique, improving the problems of IBBC. In this study, radiolucent line was observed at the margin of the socket in a small number of cases, and there was no progressive change. In addition, improvement of radiolucent line was observed in M-IBBC in this study, which was not observed in conventional cementing technique. Conclusions. It is demonstrated that M-IBBC provides stable socket cement fixation for THA. The interesting finding in M-IBBC cases was the improvement of radiolucent line, suggesting osteoconductive property of hydroxyapatite granules at the interface after the operations. The promising long-term clinical results of M-IBBC method, were expected. For any figures or tables, please contact the authors directly

Introduction. Aseptic loosening is the most common mode of failure of massive endoprostheses. Introduction of Hydroxyapatite coated collars have reduced the incidence of aseptic loosening. However bone growth is not always seen on these collars. Objectives. The aims of our study were to determine the extent of osseous integration of Hydroxyapatite coated collars, attempt a grading system for bone growth and to determine the effect of diagnosis, surgical technique and adjuvant therapy on bone growth. Methods. We reviewed the records and radiographs of 58 patients who had a massive endoprosthesis implanted by two surgeons in our unit over the last five years. Revision surgeries were recorded separately. Bone growth was graded 1–4 based on appearance in antero-posterior and lateral radiographs. Results. Three groups were identified. Group 1-Resections for primary bone tumours (33 patients), Group 2-resections for metastatic bone disease (22 patients) and Group 3- Resections for non tumour indications (3 patients). Overall, 60% of patients had grade 1, 12% had grade 2, 19% had grade 3 and 9% had grade 4 osteointegration. Grade 3 or 4 Collar osteointegration was found in 37% of patients in Group 1, 9% in group 2 and 67% in group 3. 5% of patients with grade 1 integration, 100% patients with grade 2 integration and none of the patients with grade 3 or 4 integration underwent revision for aseptic loosening. Appearance or widening of a gap between the resected bone end and the collar indicated loosening and impending revision. Proximal humeral replacements had the lowest rate of osteointegration (12%). Adjuvant therapy did not affect osteointegration. Conclusion. Osteointegration of collars is seen more often after resection of primary bone tumours. The role of collars in metastatic tumour surgery is questionable. Our radiographic grading system of bone growth predicted aseptic loosening

Introduction. Management of open fractures is challenging and requires a multidisciplinary team approach. Gustilo Anderson Type IIIB fractures reportedly have a higher infection rate (up to 52%) and up to 16% amputation rate. This study aims to evaluate outcomes of using Adjuvant Local Antibiotic Hydroxyapatite Bio-Composite in management of Open Gustilo-Anderson IIIB fractures. Materials and Methods. We reviewed a prospective data of 80 patients who presented with Gustilo Anderson Type IIIB Open Fracture to a single ortho-plastic centre. Only patients who were managed with single-stage “Fix and Flap” along with intra-operative Adjuvant Local Antibiotic Bio-Composite were included. Results. Mean follow-up time was 22 months. The mean time from injury until definitive surgery was 7.73 days (1–30 days). Primary union achieved in 88.3% within 32 weeks on average. The delayed union reported in 7.8% of patients, for the bone healing stimulated by injecting the fracture site with Autologous Bone Marrow Aspirate Concentrate. Subsequent follow-up showed signs of successful fracture healing at 60 weeks post-injury. Three patients (3.9%) had non-union. Limb salvage rate was 96.25%, and only 1.25% deep infection rate. Conclusions. Our results highlight that low infection rates, high limb salvage rates and high union rates can be achieved in these complex injuries with a combined OrthoPlastic approach, MDT input, meticulous technique and the use of adjuvant local antibiotic bio-composite. Delay in definitive surgery, gentamicin resistance and smoking were not associated with any increased deep infection or non-union in our series. At 22 months of follow-up, deep infection rate was 1.25%, limbs salvage rate was 96.25%, fracture union rate was 96.1%, and reoperation rate 18.75%

Statement of purpose. Cement fixation of total knee replacement (TKR) is commonly cited as being the gold standard, with better long-term survival rates when compared to uncemented fixation so the authors set out to analyse the longterm survivorship without aseptic loosening in a series of 471 uncemented TKR. Methods. A consecutive single surgeon series of patients undergoing routine follow up after a hydroxyapatite coated, uncemented and cruciate retaining TKR performed from 1992 to 1995 were analysed. All patients were invited for clinical review and radiological assessment. Revision of the TKR for aseptic loosening was the primary outcome. Secondary outcomes included Knee Society Score (0–200), range of movement, secondary surgical interventions and the presence of polyethylene wear or osteolysis on plain radiography. Results. 471 TKRs were performed in 356 patients (115 bilateral). 432 TKRs were accounted for through follow up. 39 TKRs in 31 pts were lost to follow-up representing 8% who had a mean KSS of 176 at 10 yr f/u. Mean f/u time period was 16.4 yrs (range 15.1–18.5 yrs). Average age at f/u was 81 yrs. 11 TKR had been revised for aseptic loosening. 19 TKRs in 19 patients had had revision of femoral/tibial components for any reason. A further 7 TKRs had undergone polyethylene insert exchange leaving an overall revision rate of 9% or 91% survival without revision. Survivorship without aseptic loosening was 96% (95%CI of 91.9–98.1%) at up to 18 years. A competing risks analysis was undertaken in order to avoid overestimation of survivorship adjusted for the competing risk of death within the study group. This analysis estimated a cumulative risk of revision for aseptic loosening at 18 years of 4.5%. Mean KSS was 176 (SD 21.5). Mean range of movement was 113 degrees of flexion. Conclusion. Uncemented hydroxyapatite coated total knee replacement can achieve favourable long-term survivorship at least as good as that of cemented designs

Purpose. The purpose of this study is to compare using a novel cementing technique with hydroxyapatite granules at bone-cement interface with using the 3. rd. cementing technique on the acetabular component. Patients and Methods. Between 2005 and 2007, we performed 54 primary cemented THAs using the 3. rd. generation cementing technique with hydroxyapatite granules at bone-cement interface (Group A: 21 hips) or without them (Group B: 33 hips) in 49 patients with dysplastic hip (6 males, 43 female; mean age at operation, 67 years; age range, 48–84 years). Mean follow up was 5.3 years (range, 2.3–7.1 years), with none of the patients lost to follow up. According to Crowe's classification, subluxation was Group I in 31 hips, group II in 11 hips, group III in 8 hips, and group IV in 4 hips. We used Exeter flanged cup, Exeter stem with a 22-mm diameter metal head (Stryker, Benoist Girard, France) and Simplex-P bone cement (Stryker, Limerick, Ireland) in all hips. A posterolateral approach was performed for all patients. Bone graft was performed 25 hips (block bone graft: 11 hips; impaction bone grafting with a metal mesh: 13 hips) from autogeneic femoral head. Our 3. rd. cementing technique is to make multiple 6-mm anchor holes, to clean the the host acetabular bed with pulse lavage, to dry it with hydrogen peroxide and to use Exeter balloon pressurizer and Exeter flanged cup. Results. The outcomes showed no aseptic loosening and radiological loosening at final follow up. Radiolucent line around the acetabular component was present 14% in Group A and 42% in Group B at 4 years after operation. Kaplan-Meier survivorship analysis of appearance of a radioluent line around the acetabuler component as the end point was 85.7% on group A was significant higher than 57.6% on group B at 4 years. Conclusion. Radiolucent line around cemented acetabular component in total hip arthroplasty using the 3. rd. cementing technique with hydroxyapatite granules at bone-cement interface was significant higher survivorship than them of the 3. rd. cementing technique at 4 years after operation. We suggest that improved novel cementing technique will lead to greater long-term success outcomes of the acetabular component

Cemented Total Hip Arthroplasty gives good results for 10 or more years, but is too often complicated by a combination of mechanical loosening, wear debris and osteolysis. Patients require an implant which will last the rest of their life. Cemented hips may not survive and a better alternative is needed. Furlong hydroxyapatite ceramic coated (HAC) implants have been used for more than 19 years and to date there are 2248 primary hip arthroplasties. Fixation of the implants with HA ceramic is entirely satisfactory; histological studies from post-mortem specimens have confirmed that there is good cancellous bone fixation to the HA. The hydroxyapatite behaves like bone and is replaced by creeping substitution. This results in a Perfect Fit with no intervening fibrous tissue. Fixation is therefore maintained. Aseptic loosening is rare; eleven components. Polythene wear is a problem. Those patients with ceramic/polythene couples who have now reached about 15 years since surgery are showing wear of the liner evidenced by eccentricity of the ceramic head in the liner. Three of these have completely destroyed the liner and the titanium shell. Ceramic/ceramic bearings do not seem to wear, although there have been occasional fractures of alumina. For the last two years Biolox Delta, a stronger compound ceramic material, has been available from Ceramtec. There are no reports of any fractures. Patients who have a life expectancy of more than 10 or 15 years should be fitted with an HA coated implant with ceramic bearing surfaces. This may provide the answer for the long-lasting hip prosthesis

Introduction. Core decompression is used in precollapse lesions to forestall disease progression in avascular necrosis (AVN) of femoral head (FH). The author reports a new technique using reverse bone graft technique to effectuate core decompression. Aim. To prevent precollapse in Ficat Type 1&2 and revascularization using synthetic bone graft material. Methods. A 18 year female police trainee with Magnetic Resonance Imaging (MRI) confirming AVN Stage 2 Ficat, clinically painful hip not evident in x-rays consented to undergo this new technique. Reverse bone graft technique with a Coring reamer – Patent 5423823. A minimally invasive technique with lateral 2 cm incision introducing 8.5 mm core reamer to remove a core of bone up to the subchondral bone. The subchondral cyst decompressed and curetted under video recorded Image Intensifier (II). Demarcated avascular bone segment excised and bone graft reversed and inserted with cortical bone acting as a support to prevent collapse and the distal segment augmented using 5 grams of osteoconductive granular synthetic bone graft material based on calcium phosphate hydroxyapatite (HA 2500–5000 μm). Avascular segment histopathologically confirmed AVN. The metaphyseal entry was extrapoliated at the lateral cortex using the combined necrotic angle described by Kerboul in the anteroposterior and lateral views under II. Protected weight bearing for 2 months to prevent stress riser. Biomaterials. HA granules named as GranuMas™ developed under Intensified Research in Priority Areas (IRPA) Research Project (No. 03-01-03-0000-PR0026/05) and invented by the Advance Materials Research Centre (AMREC) and manufactured by GranuLab –Patent P1 20040748 fulfilling the criteria for American Society for Testing and Materials (ASTM) F1185-88(1993) Standards which is ‘Standard Specification for Composition of Ceramic Hydroxyapatite for Surgical Implants’. Derived from Malaysian limestone, ranging from 200–5000 μm gamma sterilized. Results. After 6 months, there was no collapse of subchondral bone and the FH showed revascularization along bone grafted site with viable graft and increased radiotracer activity using 99-Tc MDP Bone Planar Scintigraphy. Clinical analysis follow up at 2 years was descriptive rather than statistical with a x-ray evident incorporated graft and with pain free full range of movement. Discussion. Reduction in intraosseous pressure is achieved by using large bore 8.5 mm coupled with HA granules promoting revascularization. The core tract entering through the metaphyseal region reduces risk of subtrochanteric fracture a potential complication of vascularized fibular grafts and with less morbidity with other treatment methods for osteonecrosis of the femoral head. The concept can be extended in introducing stem cell and biologic material to treat AVN. Conclusion. This technique is minimally invasive and effective in young patients with early stage of FH AVN and has shown revascularization along the bone grafted site

Diabetic foot problems are a common cause for hospitalisation in this group and up to 25% of diabetic patients will be affected. Prevalence of diabetes is rising, currently affecting 680000000 people worldwide. The enormity of this problem mandates any strategy that shortens therapeutic period and enhances success rates. Cerament G has been used in our unit as a treatment adjunct in diabetic foot treatment. Successful treatment is viewed as eradication of infection and a functional foot.

Retrospective review of 40 months practice with 115 patients. Inclusion: all diabetic feet requiring surgery Cerament G used, protocol driven Microbiology pathway. Exclusion: Primary closure not possible. Cerament G not used. Outcome assessed in three groups: Total failure (further surgery required); slow to heal (healing by secondary intention); healed without problems.

Healed 99 (eradication of infection and return to function), failure to heal 16 (success rate: 86.1%). Infection was the cause of failure in only in 2.6% (13 failures due to patient noncompliance or poor vascularity). Accepted success rate in treating osteomyelitis in diabetic feet is 68% (medical treatment only), combination of surgery and medical is 86%. Eradication of infection is the only end point return to function is not addressed. This study shows Cerament G with surgery/systemic antibiotics provides a 97.4% success rate.

Therapeutic drivers in this field have been determined traditionally by Physicians and Vascular Surgeons (resection rather than reconstructive surgery.) Our assertion is that eradicating infection in a functionally useless foot is a waste of health resources. Our strategy is always the delivery of an intact functional foot residuum. Cerament G as an adjunct allows this goal in a cost-effective manner.

Purpose. We have compared the short-term clinical results of total hip arthroplasty (THA) using PMMA bone cement and hydroxyapatite (HA) granules (interfacial bioactive bone cement method; IBBC) with the results of conventional method using PMMA bone cement. Materials and Methods. K-MAX HS-3 THA (JMM, Japan), with cemented titanium alloy stem and all polyethylene cemented socket, was used for THA implants. The third generation cement technique was used for the conventional THA (Group C) using bone cement (Endurance, DePuy). In the IBBC group (Group BC), the socket fixation was performed by the third generation cement technique with HA granules (Boneceram P; G-2, Olympus, Japan) according to the Ohnishi's method. In both groups, the stems were fixed by conventional cementing technique using cement gun. 76 hip joins (69 cases) were operated between April 2005 and August 2007, and followed. The group C (22 hips, 19 cases, average follow-up; 5.6 years, average age at operation; 64 years) and the group BC (54 hips, 50 cases, 5.4 years, 65 years) were investigated. Results. One revision was performed in BC group due to late infection. Japanese orthopaedic association (JOA) score improved from 42/48 to 85/87 in Group C/BC. Socket loosening was not observed radiographically. X-p findings of Group C/BC demonstrated radiolucent line in the outer part of Zone 1 in 18%/16% immediately after operation, 24%/23% at 2 years postoperatively. After 2 years there was no change in Group C, however, improvement of radiolucent line (gap filling) with bone remodeling was observed in two cases in Group BC at 3 years postoperatively. Conclusions. The short-term clinical results of Group BC using IBBC method and Group C using conventional method were equally satisfactory. The interesting finding in Group BC case was the improvement of radiolucent line (gap filling), suggesting osteoconductive property of hydroxyapatite granules at the interface after the operations. The promising clinical results of IBBC method in the long term were expected

Background. KAR™ prosthesis was introduced following the success of Corail® femoral stem to tackle difficult revision cases (Paprosky type1, 2a, 2b and 3a). The ARTO group reported a success rate of 94% at 17 years follow-up. Only two independent studies reported similar success rate to date. Purpose. To analyse the short-term performance of the KAR™ prosthesis used in our unit. Methods. This was a retrospective study of all KAR™ prosthesis between 2005 and 2013. Basic demographic, stem size, indications, failures and complications were recorded. X-rays were analysed for evidence of implant failure and distal cortical hypertrophy. Results. A total of 83 cases were analysed. The mean age was 68 (range 38–88 years) with an average follow-up was 3 years (range 1–8 years). The main indications for revision were aseptic loosening (83.7%), and periprosthetic fractures (7%). Kaplan-Meier Survival Rate for ‘all reasons of failure’ and ‘stem loosening’ was 93.83% and 100% respectively at 3 years follow-up. The most common reason for failure following KAR™ revision was periprosthetic fracture (3 cases). All three cases had radiographic evidence of proximal bone loss prior to index revision. Two patients developed deep infection and one patient had stem subsidence requiring revision. One patient sustained dislocation but revision surgery was not required. When comparing the effect of cortical hypertrophy, there were no significant differences in the measured distal canal/cortical diameter over the entire period of follow-up. Discussion. KAR™ prosthesis offers respectable clinical performance over a short-term period. Revision rate for this system was comparable to other ‘independent non-designer’ study. The three patients that sustained periprosthetic fracture may have been better served with a distally locked stem revision system. We believe that this HA coated implant encourages consistent osseointegration around the metaphysis region when there is evidence of a sound distal fixation. Conclusion. This study confirms that this fully coated hydroxyapatite titanium stem offers reliable clinical performance in revision arthroplasty

Introduction. Hydroxyapatite and poly-L-lactide (HA/PLLA) composites are osteoconductive and biodegradable. They have already been used clinically to treat fractured bones by inducing osteosynthesis and serving as the bone filling material. During revision of total hip arthroplasty, we have grafted bone onto the bone defect and covered it with an HA/PLLA mesh instead of using a metal mesh on the non-load bearing portion of the cup (Figure 1). However, whether the interface between the HA/PLLA and the titanium alloy cup was stable remains unclear. Objectives. The purpose of this study was to determine and compare the histological osteoconductivity and osteoinductivity of HA/PLLA and titanium alloy. Methods. Semicylindrical samples (diameter: 3 mm; height: 5 mm) were fabricated from a composite unsintered-HA/PLLA containing 40% fine HA particles and from titanium alloy (Ti-6AL-4V). These two samples were combined to form one cylinder (Figure 2). Defects 3 mm in diameter were drilled into both femoral condyles of nine Japanese white rabbits, and the samples were implanted by press fitting. The rabbits were euthanized at 2, 4, 8, and 25 weeks after implantation, and undecalcified ground samples were prepared. New bone formation was examined histologically using Toluidine blue and Villanueva Goldner stains. Results. New bone formation was observed around the sample at 4 weeks, and the amount increased by 8 weeks. In addition, partial remodeling of the trabecular bones and absorption of the HA/PLLA were found at 25 weeks. Small amounts of new bone formation were found at 4 weeks between the HA/PLLA and titanium alloy materials (Figure 3: Toluidine blue stain), and the amount increased at 8 and 25 weeks. The HA/PLLA had been slightly absorbed and new bone was formed in the gap, which was close to the border between the materials, at 25 weeks. However, the amount of absorption was limited, and no new bone was found in samples where the materials were firmly in contact. Conclusions. HA/PLLA was only slight absorbed at 25 weeks, suggesting that it was stable in vivo and has good osteoconductive and osteoinductive properties. No new bone was found in the regions where the sample was stable and had no gaps between the HA/PLLA and titanium alloy, probably because there was no space for new bone to form in those regions. In contrast, new bone formation was found in gaps of more than 20 μm. Clinically, many gaps likely exist, allowing new bone formation to occur even in a stable implant. This may stabilize the HA/PLLA and titanium alloy materials for longer times. As expected, the HA/PLLA and titanium alloy were mostly stablein vivo

Aim. Since July 2013 our group has been using an antibiotic bone substitute, composed of calcium sulphate, hydroxyapatite and gentamicin sulphate (CSH + HA + GS), in the treatment of osteomyelitis (OM) in diabetic foot. The aim of this work was to evaluate the mid-term efficacy of this treatment regime on outcomes. A favourable outcome in diabetic foot includes no recurrence of OM, healed soft tissues and the ability to weight-bear. Method. To date we have used the CSH + HA + GS bone substitute in 24 diabetic patients with OM. In this study we reviewed patients treated from July 2013 to December 2014, in which we used CSH + HA + GS to treat OM of the forefoot, midfoot and hind foot, and evaluated how many patients are able to walk and fully weight-bear at present. We identified 11 pts treated during this time period; 1 with bilateral 1. St. metatarsal-head OM due to plantar ulcers, 5 with midfoot OM secondary to Charcot deformities and ulcers, 5 with hind foot OM due to pressure ulcers or Charcot deformity. We continuously monitored the patients for recurrence of OM, ulcers and soft tissue inflammation in our outpatient department. Results. Of the 11 patients, two died during follow up (both patients had calcaneal ulcers; one died in the 1. st. month and one in the 2. nd. month after treatment, both due to cardiovascular disease). For the remaining nine patients, we had an average of 25 (17–33) months follow-up. One patient did not heal, presenting with a persistent mid-foot lesion in a Charcot foot. Another patient with bilateral forefoot ulcers had a plantar ulcer recurrence under the left 1. st. metatarsal foot, 19 months after bone substitute application and primary healing. This patient is still weight-bearing on the right foot, as are the remaining 6 patients. In 7 patients (1 with bilateral forefoot, 4 with mid-foot and 3 with hind foot OM) no recurrence of OM or ulcers was observed. Conclusions. This study suggests that a CSH + HA + GS bone substitute can be used to treat diabetic foot OM. Our mid-term results show good clinical outcomes in terms of ulcer healing, no recurrence of OM and weight-bearing

Aim. Cementless prosthesis is one of the major bone-implant interface fixation methods in total joint replacement. Grit blasted surface, hydroxyapatite coated surface and plasma sprayed metallic porous coating have been popularly used. The latter has demonstrated higher bone implant mechanical stability in previous laboratory study in early and middle stages. However, question remains what the mechanism is to make it performing better and how to improve them further. This study is designed to examine the mode of failure in bone-implant interface in a sheep model. Method. Plasma sprayed porous coated (TiPL); hydroxyapatite (HA) coated and and grit blasted (TiGB) titanium implants were examined in the study. Each type has 36 specimens. Implants were inserted into cortical bones in a press-fit fashion in a total of 22 sheep bilateral hind limbs. Specimens were retrieved at 4 weeks and 12 weeks. Push- out testing was performed to just reach ultimate failure. Failed bone-implant interface were investigated by histology and BSEM. The percentage of failure at bone-coating interface, bone itself fracture, coating itself failure, and coating-substrate dissociation were measured by BSEM. Results. In TiPL group, failure occurred mainly at new bone itself on ingrowing new bone and adjacent bone, with 74% at 4 weeks, and 82% at 12 weeks. The percentages were significantly higher than that of the failure at bone-porous coating dissociation. Furthermore, the percentage of failure occurred at bone was also higher in TiPS group than in the other groups at both time points. In HA group, the main proportion of failure, 69%, occurred at bone-HA dissociation at 4 weeks, higher than the 25% at bone itself fracture. 57% of failure occurred at HA-substrate dissociation at 12 weeks, which was followed by HA coating itself breakage (Figure 1). Bone itself fracture has the lowest proportion of only 4% breakage at 12 weeks. HA coating revealed micro cracks at some area although not all of them were failed. In TiGB group, failure mainly occurred at bone-implant surface dissociation at both time points. Conclusion. The failure mode at the HA and TiGB groups demonstrate that new bone was less likely to break, or stronger, than bone-implant surface interface at early stage, and new bone at middle stage was stronger than the other interfaces. The bone ingrowth to metallic porous coating results in that major proportion failure has to occur at bone anchorage, either at the entry level or at adjacent bone. The anchorage is the reason why TiPS has higher mechanical shear strength in previous study. Improving bone itself remodelling or maturing process may increase the porous coated implant in vivo mechanical strength; improving HA quality and HA-substrate adhesion may enhance HA coated implant performance; and improving bone implant surface bonding may strengthen grit blasted implant mechanical stability

The aim of our project is to develop resorbable nanostructured composite layer with controlled elution of antibiotics for implants survival rate enhancement. The nanostructured layers are expected to be used especially in the case of known systemic or local (joint) inflammation. This layer can provide a bone tissue/implant (titanium alloy) bioactive interface improving the physiological healing process and eliminating the risk of bacterial orthopedic infections. The main aim of this study was to verify whether the local concentration of released vancomycin exceeded the minimum inhibitory concentration (MIC) for vancomycin-resistant Staphylococcus aureus (VRSA, >16 mg/l). The layer is composed of collagen (type I, isolated form calf skin), hydroxyapatite nanoparticles and vancomycin hydrochloride (10 wt%). The stability of collagen was enhanced by EDC/NHS cross-linking. The in vitro release of vancomycin and crystalline degradation products from optimally cross-linked layers was investigated. An elution method and a high performance liquid chromatographic assay were employed to characterize the in vitro release rates of the vancomycin and its crystalline degradation antibacterial inactive products over a 21-day period. During the whole experimental period, the level of released vancomycin was high above the MIC for VRSA. The maximum average concentration was obtained between day 4 and day 8 and it reached 265 mg/l. At the end of the experiment (day 21), an average concentration of 104 mg/l was detected. Our study confirmed the prophylactic effects of studied vancomycin-loaded nanostructured layers

Aims. Will Hydroxyapatite ceramic coated (HAC) arthroplasty perform well in patients under the age of fifty?. Methods. This is a study of 269 Hydroxyapatite ceramic coated (HAC) hip arthroplasties in patients under, the age of fifty with annual review using Harris Hip Score (HHS) and plain X-rays. Assessments were over a maximum of 19 years. Early patients (46) had implants with ceramic/plastic bearings. Later patients (223) all had ceramic on ceramic bearings. Results. HHS showed 90.3% scoring over 90 or 100. Lower scores mostly relate to other joint and medical problems. Aseptic loosening and thigh pain has not been a problem. Osteolysis and debris disease have only been seen rarely in hips with ceramic on polythene bearings. Fractured alumina components have been encountered (6 heads and 3 acetabular liners, 2.1%). Ceramic/ceramic hips have otherwise remained successful. Wear in polythene liners developed in 21 patients followed up more than 15 years (45.7%). 3 have been revised. The others are currently asymptomatic. Other complications include one post operative death and 14 dislocations (5.2%). Conclusions. HAC hip arthroplasty in patients under the age of fifty does well. Hydroxyapatite bonding provides lasting implant/bone stability. No patients have thigh pain. Considering bearing surfaces, polythene will wear out and contribute to osteolysis and debris disease. Alumina bearings occasionally fracture. Zirconia Toughened Alumina has superseded Alumina which should reduce or eliminate the incidence of ceramic failure. HAC hip arthroplasty with ceramic bearings is advocated for patients under the age of fifty

Bacterial infection related to prosthetic replacement is one of the serious types of complications. Recently, there has been a greater interest in antibacterial biomaterials. In order to reduce the incidence of replacement-associated infections, we developed a novel coating technology of Hydroxyapatite (HA) containing silver (Ag). We reported the Ag-HA coating showed high antibacterial activity against E. coli, S. aureus and methicillin-resistant S. aureus (MRSA) under static condition. However, human bodies have a circulating body fluid, which is not a static condition. And the growth and the maturation of biofilm, which is said that a common course of persistent infections at a surgical site, are enhanced by the flow of broth in culture environment. Therefore, we evaluated whether the Ag-HA coating inhibits the biofilm formation on its surface or not by a biofilm-forming test under flow condition in this study. Ag-HA or HA powder was sprayed onto the commercial pure titanium disks using a flame spraying system. The HA coating disks were used as negative control. The biofilm-forming methicillin sensitive S. aureus (BF-MSSA; Seattle 1945) strain and the BF-MRSA (UOEH6) strain were used. The pre-culture bacterial suspension (about 10. 5. colony forming units; CFU) was inoculated onto the Ag-HA and HA coating disks. After cultivation at 37 °C for 1 h, the disks were rinsed twice with 500 μL sterile PBS (-) to eliminate the non-adherent bacteria. The number of the adherent bacteria on these disks was counted using culture method. After rinsing, the disks were transferred into petri-dish containing Trypto–Soy Broth (TSB) + 0.25% glucose with a stirring bar on the magnetic stirrer and they were cultured at 37°C for 7 days. In the meantime, the stirring bar was spun at 60 rounds per minute. Then, the disks were immersed in a fluorescent reagent to stain the biofilm. Finally, the biofilm on each disk was observed by a fluorescence microscope and the biofilm-covered rate on the surfaces of them was calculated using the NIH image software. The number of the bacteria on these disks was not so different between Ag-HA and HA coating after rinsing. After biofilm-forming test, the coverage of the biofilm of BF-MSSA was 2.1% and 81.0% on the Ag-HA and HA coatings, respectively. Similarly, in the case of BF-MRSA, it was 7.7% and 72.0% on the Ag-HA and HA coatings, respectively. Though bacteria slightly adhered, biofilm was hardly observed on the Ag-HA coating. The biofilm on the HA coating was extensive and mature. The inhibition effect of biofilm formation on the Ag-HA coating might be ascribed to the antibacterial effect by Ag ions released from the coating. Because Ag ions have a broad spectrum of antibacterial activity against pathogens, including biofilm forming bacteria, they inhibited the biofilm formation on the Ag-HA coating by killing adherent bacteria. Even in a flow condition, it was suggested that the AgHA shows the antibacterial activity, though the conditions in this work are different from those in living body