Periprosthetic joint infection (PJI) in geriatric and/or multimorbid patients is an enormous challenge for orthopaedic surgeons. Revision procedures have also been demonstrated to expose patients to higher infection risks. Prior patient stratification according to presumed infection risks, followed by a more potent local antibiotic prophylaxis protocol with selective use of DALBC, is an interesting strategy to decrease the burden of PJI in high risk patients. The PubMed & EMBASE databases were screened for publications pertaining to the utilization of DALBC in cement for infection prophylaxis & prosthesis fixation. 6 preclinical & 7 clinical studies were identified which met the inclusion criteria and were stratified by level of clinical evidence. Only those studies were considered which compared the PJI outcome in the DALBC vs the SALBC group. (1). DALBC have been shown to exert a much stronger and longer lasting inhibition of biofilm formation on many PJI relevant bacteria (gram-positive and gram-negative pathogens) than single gentamicin-only containing cements. (2). DALBC use (COPAL G+C) in the intervention arm of 7 clinical studies has led to a significant reduction of PJI cases in a) cemented hemiarthroplasty procedures (3 studies, evidence level I and III), in b) cemented septic revision surgeries (2 studies, evidence level III), in c) cemented aseptic knee revisions (1 study, evidence level III) and in d) cemented primary arthroplasties in multi-morbid patients (1 study, evidence level III-IV). These benefits were not associated with more systemic side effects or a higher prevalence of broad antimicrobial resistancies. Use of DALBC is likely to be more effective in preventing PJI in high risk patients. The preliminar findings so far may encourage clinicians to consolidate this hypothesis on a wider clinical range

Background. In recent years, ‘Get It Right First Time (GIRFT)’ have advocated cemented replacements in femoral part of Total hip arthroplasty (THA) especially in older patients. However, many studies were unable to show any difference in outcomes and although cemented prostheses may be associated with better short-term pain outcomes there is no clear advantage in the longer term. It is not clear when and why to do cemented instead of cementless. Aim. To assess differences in patient reported outcomes in uncemented THAs based on patient demographics in order to decide when cementless THA can be done safely. Method. Prospective data collection of consecutive 1079 uncemented THAs performed for 954 patients in single trust between 2010 and 2020. Oxford Hip Score (OHS) and complications were analysed against demographic variables (age, sex, BMI, ASA) and prosthesis features (femoral and acetabular size, offset and acetabular screws). Results. The mean pre-operative OHS was 14.6 which improved to 39.0 at 1 year follow up (P Value=0.000). There was no statistically significant difference between OHS outcome in patients aged over 70 versus younger groups. With a small number of revisable complications increase with age from 50s upwards. Male patients’ OHS score was on average 2.4 points higher than women. Men, however were 2.9 times more likely to experience fractures and high offset hips were 2.5 times more likely to experience dislocations. DAIR, intraoperative calcar fractures, post-operative fractures and dislocations were not associated with worse OHS. Patients with increased BMI had worse pre and post-operative hip functions yet, there was a significant multivariate association between increased BMI and increased improvement in OHS from pre-op to 1 year in women aged 55–80 and men under the age of 60. Femoral stem size increases with age but decreases in male patients over 80. There was no difference found in OHS between bilateral hip replacements and unilateral, nor was there any change found with laterality side of the replacement. Conclusions. This study suggests that ageing >70 is not associated with poorer outcomes despite small number of revisable complication rates that increase with age from 50 upwards. Men had marginally higher average OHS than women At 1 year. Higher BMI or ASA scores are associated with worse pre-operative hips and worse final outcome score. Despite this, the Delta OHS increases with increased BMI shown in the 55–80 year old female patients and male patients under 60. Key Words: THR, Uncemented, Oxford hip score, outcome

Introduction. Although total hip arthroplasty (THA) has been one of the most successful, reliable and common prosthetic techniques since the introduction of cemented low-friction arthroplasty by Charnley in the early 1960s, aseptic loosening due to stem-cement and cement-bone interface failures as well as cement fractures have been known to occur. To overcome this loosening, the stem should be mechanically retentive and stable for long term repetitive loading. Migration studies have shown that all stems migrate within their cement mantle, sometimes leading to the stem being debonded from the cement [1]. If we adopt the hypothesis that the stems debond from the cement mantle, the stem surface should be polished. For the polished stem, the concept of a double taper design, which is tapered in the anteroposterior (AP) and mediolateral (ML) planes, and a triple-tapered design, which has trapezoidal cross-section with the double tapered, have been popularized. Both concepts performed equally well clinically [2]. In this study, we aimed to analyze stress patterns for both models in detail using the finite element (FE) method. Methods. An ideal cemented stem with bone was made using three dimensional FE analyses (ANSYS 13). The cortical bone was 105 mm long and 7 mm thick and the PMMA cement mantle was 5 mm in thickness surrounding the stem. Young's modulus was set at 200 GPa for the bone and 2.2 GPa for the cement. Poisson's ratio was 0.3 for both materials. The bone-cement interface was completely bonded and cement-stem interface was not bonded in cases where a polished stem surface was used. The two types of stems were compared. One being the double tapered (Fig 1 left) and the other the triple tapered (Fig 1 right). The coefficient of friction (μ) at the stem-cement interface was set at 0 for both models. The distal ends of the stems were not capsulated by the PMMA and therefore the stems were free to subside. All materials were assumed to be linearly isotropic and homogeneous. The distal ends of the bone were completely constrained against any movements and rotations. An axial load of 1200 N and a transverse load of 600 N were applied at the same time simulating the bending condition [3]. Results. Although the stress distribution differences between the designs were minor, the positions where higher stresses and absolute values in the cement were observed varied. For double tapered model, the highest maximum principal stress was 1.98 MPa observed around the corner of the stem at the proximal region. For the triple tapered model, the highest maximum principal stress was 1.67 MPa observed at more medial side than the double tapered model

There has been an evolution in revision hip arthroplasty towards cementless reconstruction. Whilst cemented arthroplasty works well in the primary setting, the difficulty with achieving cement fixation in femoral revisions has led to a move towards removal of cement, where it was present, and the use of ingrowth components. These have included proximally loading or, more commonly, distally fixed stems. We have been through various iterations of these, notably with extensively porous coated cobalt chrome stems and recently with taper-fluted titanium stems. As a result of this, cemented stems have become much less popular in the revision setting. Allied to concerns about fixation and longevity of cemented fixation revision, there were also worries in relation to bone cement implantation syndrome when large cement loads were pressurised into the femoral canal at the time of stem cementation. This was particularly the case with longer stems. Technical measures are available to reduce that risk but the fear is nevertheless there. In spite of this direction of travel and these concerns, there is, however, still a role for cemented stems in revision hip arthroplasty. This role is indeed expanding. First and foremost, the use of cement allows for local antibiotic delivery using a variety of drugs both instilled in the cement at the time of manufacture or added by the surgeon when the cement is mixed. This has advantages when dealing with periprosthetic infection. Thus, cement can be used both as interval spacers but also for definitive fixation when dealing with periprosthetic hip infection. The reconstitution of bone stock is always attractive, particularly in younger patients or those with stove pipe canals. This is achieved well using impaction grafting with cement and is another extremely good use of cement. In the very elderly or those in whom proximal femoral resection is needed at the time of revision surgery, distal fixation with cement provides a good solution for immediate weight bearing and does not have the high a risk of fracture seen with large cementless stems. Cement is also useful in cases of proximal femoral deformity or where cement has been used in a primary arthroplasty previously. We have learnt that if the cement is well-fixed then the bond of cement-to-cement is excellent and therefore retention of the cement mantle and recementation into that previous mantle is a great advantage. This avoids the risks of cement removal and allows for much easier fixation. Stems have been designed specifically to allow this cement-in-cement technique. It can be used most readily with polished tapered stems - tap out a stem, gain access at the time of revision surgery and reinsert it. It is, however, now increasingly used when any cemented stems are removed provided that the cement mantle is well fixed. The existing mantle is either wide enough to accommodate the cement-in-cement revision or can be expanded using manual instruments or ultrasonic tools. The cement interface is then dried and a new stem cemented in place. Whilst the direction of travel in revision hip arthroplasty has been towards cementless fixation, particularly with tapered distally fixed designs, the reality is that there is still a role for cement for its properties of immediate fixation, reduced fracture risk, local antibiotic delivery, impaction grafting and cement-in-cement revision

Negative remodelling of the femoral cortex in the form of calcar resorption due to stress-shielding, and femoral cortical hypertrophy at the level of the tip of the implant due to distal load transfer, is frequenly noted following cemented total hip replacement, most commonly with composite beam implants, but also with polished double tapered components. The C-stem polished femoral component was designed with a third taper running from lateral to medial across and along the entire length of the implant, with the aim of achieving more proximal and therefore more natural loading of the femur. The implant is designed to subside within the femoral cement mantle utilising the cement property of creep, generating hoop stresses, which are transferred more proximally to the femoral bone, starting at the level of the medial calcar. The intention is to load the proximal femur minimising stress-shielding and calcar resorption, as well as reducing distal load transfer as signified by the lack of distal femoral cortical hypertrophy. We present the results of a consecutive series of 500 total hip replacements using C-stem femoral components, performed between March 2000 and December 2005 at a single institution. Data was collected prospectively and all patients remain under annual follow-up by a Specialist Arthroplasty Practitioner. The operations were performed using a standard surgical technique with third generation cementing using Palacos-R antibiotic loaded cement. 500 arthroplasties were performed on 455 patients with an average age at the time of surgery of 68.3 years (23-92). There were 282 (62%) female and 173 (38%) male patients with osteoarthritis being the predominant diagnosis. 77 patients have died (73 hips) and the average duration of follow-up for the entire series is 81 months (52-124). Only 2 femoral implants have been revised - one for deep sepsis and the other as part of a revision procedure for a loose acetabulum, although the femoral component itself was not loose. One implant is currently loose following a periprosthetic fracture treated by internal fixation, but none of the remaining implants demonstrates any progressive radiolucencies in any Gruen zones or any features suggestive of current or future loosening. Calcar rounding has been observed, but there have been no cases with obvious loss of calcar height and no cases of distal femoral cortical hypertrophy. The C-stem femoral component has therefore performed well in clinical practice and the objective of eradicating negative bone remodelling has been achieved. The study is ongoing

Introduction. Damage development in cemented acetabular replacements has been studied in bovine pelvic bones under long-term physiological. 1. loading, albeit dry, conditions, using a specially designed hip simulator. 2. In this work we report further experimental results from testing in wet condition in a new custom designed environmental chamber. Damage was detected and monitored using mCT scanning at regular intervals of the experiments. Two dimensional projections in the axial, sagittal and coronal planes were extracted from the 3D data for fatigue damage identification. The simulated mechanical and biological effects on the initiation and evolution of the damage of cemented acetabular reconstructs were examined and compared with those under dry condition. Materials and methods. Bovine bones were treated and reamed to receive a cemented polyethylene cup (Charnley ogee, Depuy Int) in the standard position. Standard cementing technique was utilised to apply the cement (CMW1, DePuy CMW) into the socket, with an average cement mantle thickness of 2–3 mm. The combined loading block included four routine activities, as measured by Bergmann et al. 1. , was programmed into a specially designed 4-station hip simulator for endurance testing of cement fixation. 2. A body weight of 125 kg was assumed to represent an upper bound load case and to accelerate the tests. A custom made environmental chamber (Fig. 1) was designed and built to accommodate saline solution (0.9% NaCl), where the temperature was kept constantly at 37°C. The implanted bone samples were removed from the test rig at regular intervals (100,000 and 200,000 cycles) and examined using a mCT scanner. Results and discussion. For the tests under dry condition. 2. , μCT images showed progressive development of radiolucent lines, usually in the superior-posterior quadrant near the dome region which led to gross failure; and the number of cycles to failure seems to be related to the type of physiological loadings in that the worst case was found to be descending stairs, followed by combined loading and normal walking. For the tests conducted under wet condition, debonding was detected at the bone-cement interface along the rim of the acetabulum (Fig. 2), as opposed to near the dome in the cases under dry condition. Under the same load magnitude, the survival life in cycles under wet condition is also drastically reduced (∼200,000) compared to ∼ 2,000,000 in dry condition. Conclusion. Preliminary endurance testing in physiological wet condition seems to suggest that interfacial debonding at the bone-cement interface near the rim is responsible for earlier crack initiation and failure of the acetabular fixation, as opposed to debonding near the dome region in dry condition

Purpose. We evaluated the clinical and radiographic outcomes of cementless bipolar hemiarthroplasty using rectangular cross-section stem for femoral neck fracture in elderly patients more than 80 years of age with osteoporosis. Material and Methods. 76(cemented 46, cementless 30) bipolar hemiarthroplasties for femur neck fracture were performed in elderly patients more than 80 years old. The mean follow-up period was 4.3 years (2 to 7 years). The Harris hip score at last follow-up and pre-postoperative daily living activity scale according to Kitamura methods were analyzed clinically. The radiological results were assessed using stability of femoral stem and other complications were evaluated. Results: At last follow-up, there were no significant differences of Harris hip score and daily living activity between two groups. Stem loosening and instability were not observed in cementless arthroplasty. There were 18 cases of osseous fixation in radiologic study. There were 1 case of dislocation and 1 case of superficial infection in cemented arthroplasty and 1 case of deep infection in cementless arthroplasty. Conclusion. Cementless bipolar hemiarthroplasty using rectangular cross-section stem for elderly patients with a femoral neck fracture showed satisfactory short-term clinical and radiological results compared to using cement stem

Introduction. The use of cementless TKA's has been gradually increasing over the past several years given the increasing life expectancy of our patient population. Cementless TKA's have not been rapidly adopted due to the challenges and uncertainty of tibial fixation especially in elderly patients. With the advent of new technologies, the results of cementless TKA's with the potential for long term biologic fixation may now be equivalent or better than cemented TKA's. A highly porous tibial baseplate was developed based on proximal tibial anatomy using CT scans using 3D printing technology with focus on length, location and design of press-fit pegs. Objectives. The purpose of this study was to review the early results with respect to fixation and complications using a new, highly porous cementless tibial baseplate designed for biologic fixation. Methods. One hundred primary cementless TKAs were retrospectively reviewed using a highly porous titanium tibial baseplate. The femoral and patella components were also press-fit using peri-apetite beaded technology. Patients were evaluated at 2 weeks, 3 months, 1 and 2 year for clinical and radiographic outcomes along with any early (within 90 day) and 2 year complications. Postoperative protocol consisted of immediate full weightbearing, as tolerated. Radiographs were evaluated for biological fixation and radiolucent lines. Results. There were 68 females and 32 males with 7 undergoing bilateral TKA. The mean age was 63.8 yrs (range 40–84). The mean BMI was 33.7. Diagnosis in all patients was osteoarthritis. The mean follow up was 24.8 months (range 15 to 33). The mean hospital length of stay was 3.2 days (range 2–7). The mean pre operative flexion was 105.8 degrees which improved to 117.9 degrees at latest follow up. KSS scores improved significantly in all patients. There were no postoperative transfusions in this group. All patients developed good radiographic fixation and stability of the tibial baseplate (Figure 1). There were no cases of loosening of the baseplate or infections in this series. Within 90 days, one patient developed a non fatal DVT and one patient was revised due to instability from a CR to a PS femur with the baseplate intact. At 8 months post-op, one patient had a liner exchange for MPFL rupture with a subluxating patella. At 18 months post-op, one patient had a liner exchange due to instability and extensor mechanism rupture. In both cases the baseplate was not revised. Conclusions. Study results indicate cementless fixation using this baseplate is a viable option with good short term clinical results and no cases of aseptic loosening at 2 years. Early stability, pain relief and good ROM were shown. Long term data will be required to determine the overall benefits of this highly porous TKA with biologic fixation versus cemented arthroplasty

Antibiotic-loaded bone cements are used to decrease occurrence of bone infections in cemented arthroplasties and actually being considered as a more cost-effective procedure when compared to cementless implants [1]. However, considering the challenge of treating device-associated infections there is a reduced number of formulations in the market. Response from the industry to medical need is still slow considering the rapid change in the infecting microbial profile and the emergence of multiresistant strains [2]. In this context, the aim of the work is to evaluate the role of lactose (L), as a porogen, on the antibiotic release from bone cement (BC). Levofloxacin (Lev) and minocycline (M) were the selected antibiotics to be individually loaded into BC due to their low cost and potential application in bone infections [3,4]. Two types of matrices were prepared: 1) Loaded with 2.5% of antibiotics (controls) and 2) Loaded with 10% lactose and 2.5% antibiotic. In vitro drug release and microbiological tests against representative strains causative of bone infections were assessed. Lactose significantly increased the release of both antibiotics. Complete minocycline release after one-week was observed (Fig.1A). Also, lactose increased 3.5-fold the levofloxacin released from BC (Fig.1B). Furthermore, microbiological studies showed that no interaction was observed between lactose and antibiotic as no decrease in drugs antimicrobial activity was observed (Table 1). Considering the results, L-BC matrix appears to be a valuable alternative to available formulations. Future work will include testing other antibiotics as well as mixtures of drugs. Fundação para a Ciência e Tecnologia (Portuguese government) for financial support: EXCL/CTM-NAN/0166/2012 and strategic project PEst-OE/SAU/UI4013/2011

To report our experience with the use of local antibiotic co-delivery with a synthetic bone graft substitute during a second stage re-implantation of an infected proximal humeral replacement. A 72 year old man was admitted to our department with a pathological fracture through an osteolytic lesion in the left proximal humerus, due to IgG Myelomatosis. He was initially treated with a cemented proximal humerus replacement hemiarthroplasty. Peri-prosthetic joint infection (PJI) with significant joint distention was evident three weeks post operatively. Revision surgery confirmed presence of a large collection of pus and revealed disruption of the soft tissue reattachment tube, as well as complete retraction of rotator cuff and residual capsule. All modular components were removed and an antibiotic-laden cement spacer (1.8g of Clindamycin and Gentamycin, respectively) was implanted onto the well-fixed cemented humeral stem. Initial treatment with i.v. Amoxicillin/Clavulanic acid was changed to Rifampicin and Fusidic Acid during a further 8 weeks after cultures revealed growth of S. epidermidis. During second stage revision, a hybrid inverse prosthesis with silver coating was implanted, with a total of 20 ml Cerament ™G (injected into the glenoid cavity prior to insertion of the base plate and around the humeral implant-bone interface) and again stabilized with a Trevira tube. Unfortunately, this prosthesis remained unstable, ultimately requiring re-revision to a completely new constrained reverse prosthesis with a custom glenoid shell and silver-coated proximal humeral component. 18 months postoperatively, the patient's shoulder remains pain free and stable, without signs of persistent or reinfection since the initial second stage revision. The function however, unfortunately remains poor. This case report illustrates the application of an antibiotic-eluting bone graft substitute in a specific clinical situation, where co-delivery of an antibiotic together with a bone remodeling agent may be beneficial to simultaneously address PJI as well as poor residual bone quality

Femoral component fracture is a rarely reported but devastating complication of total knee arthroplasty. It has occurred most frequently with Whiteside Ortholoc II replacements uncemented knee replacements. Presentation may be with acute pain, progressive pain or returning deformity. It occurs more commonly in the medial condyle of the femoral component. It is rarely seen in cemented replacements. All currently available literature describing fractures of condylar replacements, both cemented and uncemented. Predisposing factors include varus deformity either pre or post operatively. The mechanism of failure is thought to be failure of the infiltration of bone into the replacement. This is often due to polyethylene wear or metallosis causing abnormal tissue reaction with or without osteolysis. We present the case of a fractured Press Fit Condylar (PFC) cemented implant (DePuy, Johnson&Johnson, Raynham, Massachusettes, USA) affecting the medial condyle. To our knowledge this is only the third reported case of fracture in a PFC implant, and the first in a cemented PFC implant. Our patient was a 64 year old male who presented with unresolving knee pain post total knee arthroplasty, caused by fatigue fracture of the medial condyle of the femoral component. This was identified as loosening on plain radiographs and replaced with a revision prosthesis with a good post operative result. Given our aging population and with the increase of joint arthroplasty, this case sheds light on a potentially under recognised and increasingly important cause of knee pain following arthroplasty

The C-Stem in its design as a triple tapered stem, is the logical development of the original Charnley flat-back polished stem. The concept, design and the surgical technique cater for a limited slip of the stem within the cement mantle transferring the load more proximally. Five thousand two hundred and thirty three primary procedures using a C-stem have been carried out since 1993. We reviewed all 621 cases that had their total hip arthroplasty before 1998. Sixty nine patients (70 hips) had died and 101 hips had not reached a ten-year clinical and radiological follow-up and had not been revised. Thirty-two hips had been revised before 10 years, none were revised for aseptic stem loosening and no stems. The indications for revision were Infection in 4, dislocation in 3, aseptic cup loosening in 24 and unexplained pain in 1. The remaining 418 hips had a mean follow-up of 12 years (range 10–15 years). There were 216 women and 173 men, and 34 patients had bilateral LFAs. The patients' mean age at surgery was 53 years (range 16–83 years). Thirty four hips had been revised at the time of review. The reasons for revision were infection in 5, dislocation in 2, aseptic cup loosening in 24 and 1 for neuralgia paraesthetica where the stem was well fixed. Two hips were revised for stem fracture. There were no revisions for stem loosening but 2 stems were revised for fracture - both with a defective cement mantle proximally. The clinical results are very encouraging and they support the concept of the Charnley cemented low friction arthroplasty, but place a demand on the understanding of the technique and its execution at surgery

This study utilised NJR primary hip data from the 6. th. Annual Report to determine the rate and indication for revision between cemented, uncemented, hybrid and resurfacing prosthetic groups. Regression analysis was performed to identify the influence of gender and ASA grade on these revision rates. Validity of the data was interrogated by exploring for episodes of misclassification. Results. We identified 2,264 misclassified episodes within the four groups (Misclassification rate 2.7% primary, 4.3% revision procedures). Analysis was performed using the “reclassified dataset”. The Kaplan-Meier revision rates at 3 years were 0.9% (95%CI: 0.8%-1.0%) for cemented prostheses, 1.9% (95%CI: 1.8%-2.0%) for uncemented hips, 1.2% (95%CI: 1.0%-1.4%) for hybrids and 3.0%, (95%CI: 2.7%-3.3%) in the resurfacing group. The trends in revision rates were comparable to those published in the NJR (6. th. Ed. n. ) with significant differences across all groups (p< 0.0001). Revision rates in the under 55 year age group showed an identical hierarchy with cemented and hybrid arthroplasty having the lowest revision rates. Cox Regression analysis indicated that both the prosthesis group in isolation and the interaction between prosthesis group and ASA grade significantly influenced the rate of failure (p< 0.001). Indications for revision showed significant differences in rates for, pain, aseptic loosening, dislocation and malalignment between prosthesis types (p< 0.001). The indications including Aseptic loosening, pain, malalignment and dislocation all demonstrated similar trends in revision rates between prosthetic groups with cemented hips having the lowest rates followed by ascending rates for hybrid, uncemented and resurfacing groups. The exception being dislocation with resurfacings having the lowest revision rates. Discussion. This study provides important baseline revision rates by indication for each prosthetic group from which future comparisons can be made. Areas of misclassification within the NJR dataset have been reported back for future annual analysis

Thermal damage to bone related to the exothermic polymerisation of bone cement (PMMA) remains a concern. A series of studies were conducted to examine PMMA bone interface during cemented arthroplasty. In vitro and in vivo temperature distributions were performed in the laboratory and human and animal surgery. In vivo (10 patients) measurements of cement temperature during cementing of BHR femoral prosthesis using thermocouples. Intra-operative measurement of cement temperature in BHR in the presence of femoral head cysts was examined in patients. The BHR femoral heads were sectioned to assess cement mantle as well as position of thermocouples. An additional study was performed in sheep with PMMA implanted into cancellous defects. Thermocouples were used to monitor temperature in the cement as well as adjacent bone. Histology and CT was used to assess any thermal damage. The exothermic reaction of PMMA during polymerization does indeed result in an increase in temperature at the interface with bone. The in vivo study recorded a maximum temperature of 49.12C for approximately three minutes in the cancellous bone underneath the BHR prosthesis. This exposure is probably not sufficient to cause significant injury to the femoral head. The maximum temperature of the cement on the surface of the bone was 54.12C, whereas the maximum recorded in the cement in the mixing bowl was 110.2C. In the presence of artificial cysts within the bone, however, temperatures generated within the larger cysts, and even at the bone-cement interface of these cysts, reached levels greater than those previously shown to be harmful to bone. This occurred in one case even in the 1 cc cyst. Routine histology revealed a fibrous layer at the cement bone interface in the sheep study. Fluorescent microscopy demonstrated bone label uptake adjacent to the defect site. Histology did not reveal thermal necrosis in the defects in terms of bony necrosis. CT data was used to measure the amount of PMMA placed into each defect. This analysis revealed a range of volumes that did not seem to influence the histology. The heat of cement polymerisation in resurfacing as performed in our study is not sufficient to cause necrosis. This may reflect the ability of the body to rapidly conduct heat away by acting as a heat sink. The temperature-conducting properties of the metal prosthesis are also likely to be important

INTRODUCTION. Uncemented total hip replacement is on the rise worldwide. Latest studies from various European and other developed country joint registers are clearly showing that it is taking preference over the cemented joint replacements. These figures were discussed most recently at the London hip meeting. Our study is related to one single make of implant the Exceed hip (Biomet) at two hospitals in Northamptonshire, Kettering UK. MATERIAL & METHODS. Our series includes 256 cases of Exceed uncemented total hip replacement done in 236 patients with a minimum follow up of 6 months and maximum of 5 years. The study included 126 female and 110 male patients. Out of this number 121 cases were done at Kettering General Hospital and 135 cases were performed at Woodlands Hospital private limited in Kettering. The cases were performed by 2 senior consultants and one junior consultant. The total number of cases was 317 but 73 cases were lost to follow up and 2 patients had expired at the time of the study. In all cases pre operative and post operative Harris hip scores were measured. Patients were asked to fill up the scores in retrospect through post. The range of motion parameter and range of motion scale were measured and added from clinical notes. The average age of patients in our study was 71.2 years with the oldest patient being 90 years old and the youngest being 34 years old. Most common cause for replacement was primary osteoarthritis in 202 cases. In 52 cases it was done for secondary osteoarthritis due to rheumatoid arthritis or post traumatic osteoarthritis following dislocation and acetabular fractures. In 2 cases it was done for fracture neck of femur. All the cases were done through posterior approach. One senior surgeon used bone grafts in the acetabular floor harvested from the femoral head at time of surgery in all of his cases. The ABT ringloc shell, polyethylene liner was used in all cases. The average pre operative Harris hip score was 43.15 and average post operative Harris hip score was 78.32. In 4 cases peri prosthetic fractures occurred per operatively and needed fixation. In 3 cases dislocation occurred but only one case needed revision due to recurrent dislocation. DISCUSSION. Our early results are showing encouraging results with the Exceed uncemented total hip replacement prosthesis. The Harris hip score post operatively shows good improvement and satisfaction. In two cases there was unexplained pain along the thigh and groin. One of these cases was post dislocation. The dislocation rate was around 1.2% and periprosthetic fracture rate was 1.6%. Longer follow up is needed to evaluate and compare the results of this particular implant with the other studies on uncemented total hip replacement that have been published in literature