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

Introduction

Uncemented press-fit cups provide bone fixation in primary total hip replacement (THR). However, sometimes screws are needed to achieve primary stability of the socket. We analyzed biomechanical factors related to press-fit in seven cup designs and assessed whether screw use provides similar loosening rates to those of the press-fit technique.

Introduction

Dislocation is one of the most important complications after primary total hip replacement (THR). The low incidence of this finding makes it difficult to analyse the possible risk factors. The surgical technique can also influence this rate through cup position or an adequate reconstruction of the hip.

We assessed the demographic data and radiological reconstruction of the hip related to the appearance of dislocation after primary THR.

Introduction

Hydroxyapatite (HA) coated femoral stems require a press fit for initial stability prior to osteointegration occurring. However this technique can lead to perioperative femoral fracture.

Although cemented fixation provides excellent results in primary total hip replacement (THR), particularly in patients older than 75 years, uncemented implants are most commonly used nowadays. We compare the rate of complications, clinical and radiological results of three different designs over 75-years-old patients.

Objectives. To examine mortality and revision rates among patients with osteoarthritis undergoing hip arthroplasty and to compare these rates between patients undergoing cemented or uncemented procedures and to compare outcomes between men undergoing stemmed total hip replacements and Birmingham hip resurfacing. Main outcome measures. Hip arthroplasty procedures were linked to the time to any subsequent mortality or revision (implant failure). Flexible parametric survival analysis methods were used to analyse time to mortality and also time to revision. Comparisons between procedure groups were adjusted for age, sex, American Society of Anesthesiologists (ASA) grade, and complexity. Results. Multivariable survival analyses identified a higher mortality rate for patients undergoing cemented compared with uncemented total hip replacement (adjusted hazard ratio 1.11, 95% confidence interval 1.07 to 1.16); conversely, there was a lower revision rate with cemented procedures (0.53, 0.50 to 0.57). These translate to small predicted differences in population averaged absolute survival probability at all time points. For example, compared with the uncemented group, at eight years after surgery the predicted probability of death in the cemented group was 0.013 higher (0.007 to 0.019) and the predicted probability of revision was 0.015 lower (0.012 to 0.017). In multivariable analyses restricted to men, there was a higher mortality rate in the cemented group and the uncemented group compared with the Birmingham hip resurfacing group. In terms of revision, the Birmingham hip resurfacings had a similar revision rate to uncemented total hip replacements. Discussion. There is a small but significant increased risk of revision with uncemented rather than cemented total hip replacement, and a small but significant increased risk of death with cemented procedures. It is not known whether these are causal relations or caused by residual confounding. Compared with uncemented and cemented total hip replacements, Birmingham hip resurfacing has a significantly lower risk of death in men of all ages. Previously, only adjusted analyses of hip implant revision rates have been used to recommend and justify use of cheaper cemented total hip implants. Our investigations additionally consider mortality rates and suggest a potentially higher mortality rate with cemented total hip replacements, which merits further investigation. These results have now been confirmed by other Centres as well. [1,2] Our findings agree with those of Kendal et al who confirm that those undergoing metal-on-metal hip resurfacing have reduced mortality in the long term (up to 10 years) compared with those undergoing total hip replacement and that this difference persisted after extensive adjustment for confounding factors. Although residual confounding is possible, the observed effect size is large

Introduction. Dislocation of an uncemented total hip replacement (THR) can cause damage to the femoral hear, when it passes through the rim of metal acetabular shell. This can lead to metal transfer on the surface of the head or chipping of bulk head material. Although dislocation is one of most common complications in total hip arthroplasty (THA), little is known if causes any further damage to the articulating surface of ceramic heads in long term observations. Aim of the study. To evaluate, if dislocations of THR with ceramic on polyethylene bearing causes structural damage to the articulating surface of the femoral head in a follow-up of minium 10 years. Materials and methods. MATERIAL. This study included four groups of third generation (CeramTec Biolox forte) ceramic femoral heads with a diameter of 28 mm:. 8 heads dislocated in the first year(managed nonsurgically) where implants functioned for at least 10 years. 9 heads removed within 12 months after implantation because of recurrent dislocations. 11 heads retrieved after a minimum of 10 years from hips where no dislocation occurred. 8 unused heads. METHODS. Surface topography of retrieved heads was evaluated using Scanning Electron Microscopy with Energy – Dispersive X-ray Spectroscopy; roughness measurements were performed in three directions (0, 45,90 degrees) over a distance of 1,5 mm using a contact profilometer. Results. On the dislocated heads dark stained scratches were present in the lower, non weight-bearing part; SEM studies demonstrated presence of multidirectional smear-like metal deposits (Fig 1) with a small number of chipped ceramic grains. EDS analysis of scratches indicated presence of Ti or Ti,Al,V - dependant on construction alloy of the acetabular component. There were no differences in morphology of scratched areas between heads removed within a few months after dislocation and components retrieved after at least 10 years. Interestingly SEM findings within the weight-bearing part of dislocated heads were identical within corresponding areas of femoral heads articulating for 10 or more years as well as unused components (Fig 2). In these areas we observed a small number of pinholes and scratches, which we believe resulted from machining and subsequent polishing. Roughness measurements were consistent with SEM findings (Table 1). Areas covered by metal deposits had a significantly higher roughness compared to undamaged area. We did not observe statistical differences between roughness of weight-bearing area in all examined groups. Conclusions. Our study indicates, that dislocation of femoral head in a uncemented total hip replacement with ceramic on polyethylene bearing results in contained damage in the area which contacted the metal acetabular shell. Dislocation does not affect the weight-bearing surface of the head, even in a long-term follow-up. This study was financed by a National Science Centre grant No. 2012/05/D/NZ5/01840

Introduction. Durable bone fixation of uncemented porous-coated acetabular cups can be observed at a long-term, however, polyethylene (PE) wear and osteolysis may affect survivorship. Accurate wear measurements correlated with clinical data may offer unique research information of clinical interest about this highly debated issue. Objetive. We assessed the clinical and radiological outcome of a single uncemented total hip replacement (THR) after twenty years analysing polyethylene wear and the appearance of osteolysis. Materials and Methods. 82 hips implanted between 1992 and 1995 were prospectively evaluated with a mean follow-up of 20.6 years (range, 18 to 23). A hemispherical porous-coated acetabular cup matched to a proximally hydroxyapatite-coated anatomic stem and a 28 mm standard PE liner, sterilised by gamma irradiation in air, was used in all hips. Radiological position and the possible appearance of loosening and osteolysis were recorded over time. Penetration of the prosthetic head into the liner was measured by the Roentgen Monographic Analysis (ROMAN) Tool at 6 weeks, 6 months, one year and yearly thereafter. Results. Six cups were revised due to wear and four due to late dislocation. All cups were radiographically well-fixed and all stems showed radiographic ingrowth. Six un-revised hips showed osteolysis on the acetabular side and two on the proximal femoral side. Creep at one year was 0.30 (±0.23) mm. Mean total femoral head penetration was 1.23 mm at 10 years, 1.52 mm at 15 years and 1.92 mm at 23 years. Overall mean wear was 0.12 (± 0.1) mm/year and 0.09 (±0.06) mm/year after the creep period. Mean wear was 0.08 (± 0.06) mm/year in hips without osteolysis and 0.14 (±0.03) mm/year in revised hips or with osteolysis (p<0.001). Conclusions. Although continued durable fixation can be observed with a porous-coated cups and a proximally hydroxyapatite-coated anatomic stem, true wear continues to increase at a constant level over time. PE wear remains as the main reason for revision surgery and osteolysis in uncemented THR after twenty years

Introduction. The use of screws is frequent for additional fixation, however, since some disadvantages have been reported a cup press-fit is desirable, although this can not always be obtained. Cup primary intraoperative fixation in uncemented total hip replacement (THR) depends on sex, acetabular shape, and surgical technique. We analyzed different factors related to primary bone fixation of five different designs in patients only diagnosed with osteoarthritis, excluding severe congenital hip disease and inflammatory arthritis, and their clinical and radiological outcome. Materials y Methods. 791 hips operated in our Institution between 2002 and 2012 were included for the analysis. All cases were operated with the same press-fit technique, and screws were used according to the pull-out test. Two screws were used if there was any movement after the mentioned manoeuvres. Acetabular and femoral radiological shapes were classified according to Dorr et al. We analyzed radiological postoperative cup position for acetabular abduction angle, the horizontal distance and the vertical distance. Cup anteversion was evaluated according to Widmer and the hip rotation centre according to Ranawat. Results. Screws were required in 155 hips (19.6%) and were more frequently used in women and patients with a type A acetabulum (p<0.001, p=0.021, respectively). There were no differences among the different cups evaluated. The need for screws was more frequent in hips with a smaller version of the cup and with a distance greater than 2 mm to the approximate femoral head centre from the centre of the prosthetic femoral head (p=0.022, 0.012, respectively). Adjusted multivariate analysis revealed that female patients (p<0.001, Odds Ratio (OR): 2.063; 95% Confidence Interval (CI) 1.409–3.020), cups with a smaller version (p=0.012, OR: 0.966, 95% CI 0.94–0.992), and a greater distance to the rotation hip center (p<0.005, OR: 1.695; 95% CI 1.173–2.450) had a higher risk for screw use. No hips needed revision for aseptic loosening. Conclusions. Cup press-fit depends on gender and surgical technique in hips without significant acetabular abnormalities or inflammatory arthritis. Contemporary uncemented cups provide similar primary fixation and mid-term outcome

Introduction. Proper femoral reaming is a key factor for a successful outcome in cementless hip arthroplasty. Good quality reaming minimizes risks of intra-operative femoral fracture during reaming and prevents poor fitting of the implant which can lead to subsidance of the stem postoperativly. Determining the quality of reaming is largely a subjective skill and dependant on the surgeon's experience with no documented intraoprative method to assess it objectively. Method. We recorded and analysed the frequencies of sound signals recorded via a bone conduction microphone during reaming of the femoral canal in a series of 28 consecutive patients undergoing uncemented total hip replacement performed by same surgeon. Hammaring sound frequencies and intensity were analysed by mean of computer software. The relationship between the patterns of the recorded reaming sound frequencies compared with surgeon judgment of the reaming quality intraoparativly and post operative x rays. All patients were followed up clinically and radiologically for 2 years after surgery to determine the integrity of the fix and to evaluate the stability of the prosthesis. Results. There was a consistent pattern of frequency changes detected in all cases regardless of gender, age, bone density size of reamer etc. Our results showed that the resonances in the femur can be accurately recorded during canal reaming and proved that there is a definite increase in the amplitude of sound frequencies between 600 and 1000 Hz when the tension of the reamer moves from loose to tight during hammering. Adding all of the dB values between 600 to 1000 Hz for the loose tension sound and comparing this to the total for the tight tension sound showed an average of 449.6% increase. Our Analysis of the sound signals changes was comparable to the adequacy of the reaming postoperatively. Conclusion. There are identifiable audio frequency patterns changes associated with satisfactory reaming of the femoral canal. Our findings may pave the way for the development of a real-time intraoperative reaming audio analyser which can guide the surgeon to the optimal reaming tension

Purpose. The purpose of this study was to determine the functional outcome, imaging and complications of conversion of hip fusion to uncemented total hip replacement. Method. The study group comprised eighteen patients who had undergone conversion of unilateral hip fusion to total hip replacement between 1996 and 2007. There were five men and 13 women. The diagnosis prior to fusion was traumatic injury in eight patients, developmental dysplasia in three patients, and septic arthritis in seven patients. Four of the patient who had septic arthritis in childhood had spontaneous hips fusion while the other underwent surgical arthrodesis. The mean age at the time of conversion was 53 years (range, 21–77) and the mean time between fusion and conversion to hip replacement was 33 years (range, 11–60). Mean follow up was five years (range 2–15 years). Data was collected by retrospective review of a prospective database. Uncemented acetabular components were used in all cases and uncemented femoral components were used in all but two patients. In three patients with abductor and soft tissue deficiency an intraoperative decision was made to use a constrained acetabular liner. Results. The Harris hip score increased from a mean of 49 pre operatively to 75 at a mean of five years p<0.001. There was poor correlation between patient age, duration of hip fusion and hip scores at six months, 12 months and at final follow-up at a mean of five years. Heterotopic ossification developed in seven of the 18 (39%) patients. It was grade one in four patients, grade two in one patient, grade three in one patient and grade four in one patient. Four complications occurred in four of the 18 (22%) patients. Two patients (11%) had neurological injury in the common peroneal nerve distribution. In one patient heterotopic ossification resulted in joint ankylosis. This patient underwent reoperation to excise the heterotopic ossification 16 months after the initial hip replacement procedure. One patient developed a deep venous thrombosis. There were no hip dislocations. One acetabular component was loose and had migrated at 15 years follow up. Conclusion. Conversion of hip fusion to hip replacement carries an increased risk of heterotopic ossification and neurological injury. We advise prophylaxis against heterotopic ossification. When there is concern about hip stability we suggest that the use of a constrained acetabular liner is considered. Despite the potential for complications, this procedure had a high success rate and was effective in restoring hip function

Pseudotumour formation is being reported with increasing frequency in failing metal-on-metal hip resurfacings and replacements. This mode of failure complication has also been reported with metal-on-polyethylene bearing bearings when it is usually associated with evidence of surface corrosion and no apparent wear at the head–neck taper. We present a case with evidence of taper wear and damage secondary to corrosion in an uncemented total hip replacement with a metal on polyethylene articulation (TMZF (Titanium, Molybdenum, Zirconium and Ferrous) Accolade® stem, Trident® HA coated acetabular shell, Low Friction Ion Treatment (LFIT™) Cobalt-Chrome anatomic head (40 mm), X3® polyethylene liner). Case. A 69 year old woman had a THR in 2008. A year later she started to complain of lateral based hip pain. Clinical examination and initial imaging indicated trochanteric bursitis and heterotopic bone formation. The symptoms became worse over the next 3 years and the patient was listed for exploration and excision of heterotopic bone. Surgical findings. Extensive pseudotumour was encountered deep to bursa and adherent to capsule. Abductors, external rotators and vastus lateralis were spared. There was minimal calcar osteolysis and marginal erosion in superior acetabulum. There was no obvious wear on the articulating surfaces of the femoral head and polyethylene inlay of the socket nor was there any evidence of neck-to-rim impingement or edge loading. There was visible blackening of both the taper and trunnion after femoral head removal. Results. Peripheral blood samples taken at the time of surgery recorded Cobalt 107 nmol/L, Chromium 9 nmol/L. Wear Measurements. These were performed on the articulating surfaces and the head taper using the RedLux Artificial Hip Profiler. No discernable wear was noted at the articulating surfaces. Qualitative 3-D surface mapping demonstrated a trunnion imprint on head taper of 10.1 mm in length. At the distal end of the taper this was incomplete indicating possible taper/trunnion incongruity. The majority of the material loss was demonstrated at the proximal end on the polar opposite side to incomplete imprint (Figure 1). Corrosion analysis. The head was sectioned for more detailed surface analysis of areas of interest. This demonstrated a polished region just inside the taper (G), followed by a deep pit (F), a region of extensive pitting (E) and running along the taper length were longitudinal needle like pits (D) indicative of a path of fluid ingress (D-G ref Fig 2.). These findings were more suggestive of crevice corrosion than mechanical wear. Histology. There was evidence of aseptic lymphocytic vasculitis-associated lesion (ALVAL) scoring 8 out of 10 (as per Campbell et al). With the continuing increase in the use of larger head sizes the findings of pseudotumour formation and taper damage in a commonly used hip replacement raises considerable concern. Wear analysis has highlighted that although there is evidence of motion occurring at the taper / trunnion interface, corrosion appears to be the dominant mechanism of damage to the taper. In addition to the use of larger head sizes this case also raise concerns about the compatibility of certain metal alloy combinations

Uncemented metal-on-polyethylene total hip arthroplasties (THAs) have had a modular cobalt-chrome alloy head since their introduction in the early 1980's. Retrieval analysis studies and case reports in the early 1990's first reported corrosion between the femoral stem trunnion (usually titanium alloy) and cobalt-chrome alloy femoral head. However, then this condition seemed to disappear for about two decades? There are now numerous recent case series of this problem after metal-on-polyethylene THA, with a single taper or dual taper modular femoral component. Metal ion elevation, corrosion debris, and effusion are caused by mechanically assisted crevice corrosion (MACC). These patients present with diffuse hip pain, simulating trochanteric bursitis, iliopsoas tendinitis, or even deep infection. Trunnion corrosion, with adverse local tissue reaction, is a diagnosis of exclusion, after infection, loosening, or fracture. The initial lab tests recommended are: ESR, CRP, and serum cobalt and chromium ions. With a metal-on-polyethylene THA, a cobalt level > 1ppb is abnormal. Plain radiographs are usually negative, but may show calcar osteolysis or acetabular erosion or cyst. MARS MRI may be the best imaging study to confirm the diagnosis. Hip aspiration for culture and cell-count may be necessary. The operative treatment is empiric, with debridement, and head exchange with a ceramic head-titanium sleeve (or oxidised zirconium head) placed on the cleaned trunnion. The femoral component may have to be removed if there is “whole trunnion failure”. This usually relieves the symptoms, but the complication rate of this procedure may be high