Juvenile idiopathic arthritis (JIA) affecting the hip can cause debilitating pain and walking disability in children. Total hip replacement offers the potential of a pain free joint and a significant improvement in function. There remains the concern regarding the high rates of aseptic loosening of cemented total hip replacements in this group of patients, and there is evidence that younger patients have higher failure rates. The aim of this study was to look at the results of uncemented total hip replacement in children with Juvenile Idiopathic Arthritis and in particular to assess any problems associated with performing this surgery in the presence of open growth plates in the acetabular and trochanteric regions. Between 1995 and 2005, 56 uncemented total hip replacements were carried out in 37 children with JIA with a mean follow up of 7.5 years (range 3 to 12.5). 25 of the hips had ceramic on ceramic bearings. The mean age at surgery was 13.9 years (range 11–16). 19 patients underwent bilateral procedures. All patients showed a significant improvement in their HSS Hip scores (p< 0.01). Two CAD CAM femoral stems were revised for gross subsidence and three acetabular components were revised for loosening. Four polyethylene liners were exchanged due to wear. 51 of 53 (96%) femoral stems and 50 (94%) acetabular components remain well fixed at latest follow up with no signs of loosening. There were no dislocations or infections. Uncemented fixation appears to work well in this challenging group of patients even in the presence of open growth plates. Implant choice is important to avoid problems of subsidence and loosening. Ceramic bearings available for small implant sizes give promise of improved performance compared to polyethylene over the long term

Introduction: The benefits of total hip replacement in patients with juvenile idiopathic arthritis are well documented. However only few results of uncemented total replacement with subsequent problems of loosening and revision surgery have been published. We report a minimum 2 year follow-up of uncemented total hip replacement in this group of patients. Material s& Methods: Between 1995 and 2003, 56 patients under the age of 29 years underwent 81 uncemented total hip replacements. 41 were females and 15 were males.1 patient died and 1 lost for follow -up. The average length of follow up was 6 years (range 2 to 10 yrs). In 67% of the patients the follow up period was 5 yrs or longer. The average age of onset of the disease was 5 yrs (range 1 to 19 yrs). The mean age at surgery was 18 yrs (range 11 to 29 yrs). Both hips were involved in 25 patients of which 18 were women and 7 were men. The mean interval between the onset of arthritis and surgery was 11 yrs. The mean interval between symptoms of hip involvement and hip replacement was 4.7 yrs. In 49% of patients the onset of arthritis was systemic, 22.6% polyarticular, 15.09% pauciarticular and 13.21% seronegative. Prior soft tissue release was performed in 6 hips(4).2 patients had previous supra-condylar femoral osteotomy for deformity correction.2 patients had total knee replacements(bilateral 1, unilateral 1). Usually a posterior approach was employed. A variety of prosthesis were used, Furlong HAC stem in 40 patients, SROM in 23 patients and CAD CAM in 17 patients. On the acetabular side, Furlong CSFHDP in 31 patients, Furlong ceramic in 15 patients, SROM cup in 21 patients, Duraloc cup in 9 patients and Muller support ring in 4 patients. The hips were graded before surgery and at follow-up using the scoring system of the Hospital for Special Surgery (Salvati and Wilson 1973). Results: The mean improvement of HSS score for pain, ROM, mobility and function are 6.3, 3.1, 3.5 and 4.1 respectively. There was a mean improvement of 17.0 in the total HSS score. One patient had subsidence of both the CAD CAM stems at present waiting for revision. Radiolucent zones around the proximal sleeve SROM stem was noted in one patient requiring stem revision. Stress shielding of calcar was noted in 3 patients (CAD CAM 2, Furlong 1) and osteolysis around the cup in 1 patient. All patients with Furlong stem had very good osseointegration and there was no need of any revision. All patients with SROM stems also had very good osseointegration except one for which stem revision was done. Conclusion: This study shows a lower revision rate and better radiographic appearance compared to previous reports with similar follow up of THA in Juvenile Idiopathic Arthritis

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

During revision THR, the surgery is often difficult and compromised due to lack of patient's bone especially in the pelvis. Any extra bone in the acetabulum is expected to be of advantage to the patient and the surgeon. The aim of this study was to see if preservation of medial acetabular osteophyte in uncemented total hip replacement had any adverse effect on the prosthesis survival or patient satisfaction. Conventional acetabular preparation involves reaming down to the true floor. This not only medialises the centre of rotation of the hip but also reduces the acetabular offset. In contrast the main surgeon preserved the acetabular offset by preserving some osteophytic bone between the true floor of the acetabulum and the acetabular cup. This is achieved by reaming the acetabular cavity conservatively while achieving secure primary fixation of the prosthesis. We report the outcome of a single surgeon series of such cases. The endpoint was assessed as the need for revision of the acetabular cup. A total of 106 consecutive patients were identified who underwent uncemented THR from 2005 to 2010. The medial osteophyte was measured on immediate post-operative x-rays, from the “teardrop” to the nearest point of the acetabular cup, by 3 surgeons (one consultant and 2 registrars). The patients were contacted for a telephone interview and their clinical notes, including x-rays, were reviewed. Outcome was available for 79 patients. 74 patients were available for follow-up and 5 patients died unrelated to THR. Average follow-up was for 8.3 years (range 5.5–10.8). Average age was 62 years. The average medial osteophyte was 1.98 mm (range 0–14mm). One patient had late infection and one had dislocation. There was not a single failure of the acetabular component. The patient satisfaction was high at 8.8 out of 10. Preservation of medial osteophyte in the acetabulum whilst doing uncemented THR has the advantage of retaining the patient's own bone stock which can be of great advantage to the surgeon as well as the patient should revision THR be required in future. Our study has shown that this can be achieved without compromising the survival of the prosthesis or the patient satisfaction. This technique may increase the range of motion of the hip by reducing the risk of bony or soft tissue impingement, and also reduce the risk of dislocation. Furthermore, not recreating the native centre of rotation of the hip does not seem to have any adverse effect for the patients, who are very happy with the outcome. We recommend that whilst doing uncemented THR, the acetabulum should not be reamed to the true floor as has been the conventional teaching, but attempt should be made to preserve some medial osteophyte where possible, at the same ensuring that good primary fixation of the cup is achieved. This is to give the patient and surgeon the advantage of extra available bone should revision surgery be required in the future

Aims: To establish the frequency of achieving the desired prosthesis position in an uncemented total hip replacement and the effect of the position on outcome. Methods: We reviewed the earliest and most recent available post-operative pelvic x-rays of 96 patients who had undergone a total hip replacement between March 1992 and December 1995. A press þt hydroxyapatite coated cup and stem were used in all cases (CSF & JRI respectively). We assessed the following parameters: Centre of rotation, off set, cup angle, leg length and insert wear. We then established the clinical outcome at 5–9 years of 88 patients using the MDP scoring systems and correlated this with the radiological study to establish the effect of prosthesis placement on the clinical outcome. Results: There was an acceptable centre of rotation in 53.6% of the patients, 44% of the patients had a cup angle of 40–49 degrees, 73% had an adequate off set and 71.7% had equal leg lengths. There was no correlation between the MDP and the centre of rotation, cup angle, off set or leg length. There was also no correlation between these parameters and wear of the liner. Conclusion: It is evident that the desired position of the prosthesis is not achieved in a signiþcant number of patients. This does not seem to correlate with the clinical outcome and wear. Extreme deviation from the anatomical position is likely to be detrimental

Polyethylene wear in total hip arthroplasty Is associated with generation of particulate wear debris and component failure. Wear has both mechanical and biological consequences with one of the most important of these being the stimulation of immune medicated periprosthetic osteolysis in response to polyethylene particles. It has been shown that the amouont of wear debris generated correlates with the degree of osteolysis encountered. Unfortunately, the assessment of wear of components remains difficult and we wished to apply a new digitised technique of measuring wear using engineering computer softwear on a population of uncemented total hip replacement (THR) patients. Forty patients having primary uncemented THR (ABG 1 prosthesis) for osteoarthritis were enrolled in the study. Seventeen had a 28mm femoral head implanted and 23 had a 32mm head. There were 28 females and 12 males concerned, all having standardised (120 cm hip to x-ray tube) ;weight bearing antero-posterior plain radiographs of the hip performed in the immediate post-operative period and again at a mean of 6 years post-operatively (range 54 – 96 months). The x-rays were then scanned to computer and analysed using Autocad software. The analysis essentially involved 4 steps, namely assessing sphericity of the cup, sphericity of the head, superimposition of the post-operative and 6 year radiographs an.d obtaining computer generated analysis of both the amount and direction of wear. The results of our analysis demonstrated that there was an overall mean wear of 0.157mm per year (range 0.08 – 0.27mm). Of the 17 patients with a 28mm head the mean wear was 0.143mm per year, whereas the 32mm heads were associated with a mean wear rate of 0.188mm per year, with the difference reaching statistical significance (p=0.004). Analysis of the direction of wear demonstrated that as expected wear typically occurred in a superolateral direction with a mean vector of 9° lateral to the vertical axis of the hip. These results primarily demonstrate the usefulness of appropriate computer software in determining wear of components in THR. This allows for assessment of rate and degree of wear which may be important in identifying patients at particular risk of developing significant osteolysis, loosening and ultimately component failure. The results are also consistent with previous reports of increased volumetric wear with large diameter heads and direction of wear in retrieval studies. It is therefore promising as an investigative tool for the in vivo assessment of inovations in THR design in the future

Aim: To compare the difference in periprosthetic bone density between cemented and uncemented total hip replacement at a minimum follow up of 10 years. Patients and methods: We looked at a cohort of 17 patients who have had bilateral total hip replacement with cemented Charnley total hip on one side and uncemented Furlong total hip on the other side between 1984 and 1994 (minimum follow up 10 years). Harris and Oxford hip scores were used to determine the function, SF 36 was used to measure quality of life and Dual energy X-Ray absorptiometry (DEXA) scan was used to quantify bone mineral density adjacent to the prosthesis. The results from the DEXA scan for cemented and the uncemented hips were analysed using Paired samples two tailed t-tests. To compare the Harris hip scores, a non-parametric Wilcoxon test was used. Pearson correlations were carried out to examine the relationship between the bone density measures (averaged for each zone) and the quality of life measures. Results: Bone mineral density was higher on the Furlong side in Gruen Zones 2, 3, 5 and 6 of the proximal femur and DeLee Charnley Zone 1 of the acetabulum. In all other zones there was no statistical difference. Comparison of Harris hip scores and Oxford hip scores showed no statistically significant difference between the two hips (p = 0.108). Age is negatively correlated with bone density in Gruen zones 6 and 7 and acetabular zones 2 and 3. Conclusion: Bone density is better preserved around the uncemented HAC coated stem compared to the Charnley cemented stem

Introduction: Since 2000 all total hip replacements have been subjected to a continuous quality control. We report an increasing rate of postoperative fractures around uncemented femoral components after minimal or no trauma.

Methods: Four to 6 weeks after the THR all patient files and radiographs are evaluated and demographic data, complications and radiographic position of the implant registered. Surgery was performed according to the manufacturer’s instructions, and full weight bearing was allowed. If a fracture occurred during the first postoperative weeks a further analysis of the case was performed.

Results: During the 9 years 3.295 primary total hip replacements were performed. In the period the use of uncemented THR increased from 41% to 99%. Totally 69 fractures in 2.408 uncemented THR’s (2.9%) were registered, and 28 of these were of the proksimal split fracture type occurring without any previous trauma. The fractures occurred after a few days up to 4 weeks after surgery and were characterised by a vertical femoral fracture from the calcar to the medial femoral region 5 to 7 cm below the lesser trochanter. All cases were seen in women, but were not correlated to age, BMI or previous femoral neck fracture. In most cases treatment was internal fixation with a trochanteric grip and cables and insertion of a new uncemented femoral component.

Conclusion: The increased use of uncemented femoral components implies a substantial risk of subtrochanteric femoral fracture. The cause of these fractures is unknown, but probably multifactorial. It could be due to a mismatch between the instruments and the prosthesis, to undiagnosed weakness of the bone, or to the vigorous mobilisation made possible by the effective modern treatment of postoperative pain.

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.

The aim of this study was to investigate the use of large diameter head THR to treat fractured neck of femur, and to demonstrate if this conferred greater stability.

46 independent, mentally alert patients with displaced intracapsular fractures underwent THR. Mean age was 72.1 years. Outcome measures were dislocation, reoperation/ revision rate, Oxford hip score (OHS), Euroqol (EQ-5D) and residential status. Data was collected prospectively, with review being carried out at 3 months and 1 year.

At mean follow-up (12.5 months) there were no dislocations. Reoperation, revision and infection rate were all 0%. Two patients died (4.3%). Mean pre-injury and postoperative OHS were 12.1 and 17.9 respectively. Mean pre-injury and postoperative EQ-5D index scores were 0.97 and 0.83 respectively. Mean postoperative walking distance was 2.5 miles. There were no changes in residential status.

This is the first published series utilising 36-mm diameter metal-on-metal THR for the treatment of fractured neck of femur. We have demonstrated that it affords patients excellent stability with no recorded dislocations.

Dislocation is a major concern following total hip replacement (THR) for fractured neck of femur. The aim of this prospective study was to investigate the use of large diameter femoral head uncemented THR to treat fractured neck of femur, and to demonstrate if the improved stability seen in previous clinical situations with these designs, can be used to benefit this difficult subgroup of patients that are particularly prone to dislocation.

Forty-six consecutive independent, active and mentally alert patients with displaced intracapsular fractured neck of femur underwent large diameter head uncemented THR. The mean age of patients was 72.1 years. The outcome measures used were the dislocation rate, reoperation and revision rate, Oxford hip score (OHS), Euroqol (EQ-5D) and residential status.

Clinical and radiological data were available on all 46 patients. At a mean follow-up of 12.5 months there were no dislocations. The reoperation, revision and infection rate were all 0%. Two patients died (4.3%) from unrelated causes. Mean pre- and postoperative OHS were 12.1 and 17.9 respectively. The mean pre- and postoperative EQ-5D index scores were 0.97 and 0.83 respectively. The mean postoperative walking distance was 2.5 miles and there were no changes in residential status.

This is the first published series utilising a 36-mm diameter metal-on-metal THR for the treatment of fractured neck of femur in mobile, independent patients. We have demonstrated that it affords patients excellent stability with no recorded dislocations.

Dislocation is a major concern following THR for fractured neck of femur. The aim of this prospective study was to investigate the use of large diameter femoral head uncemented THR to treat fractured neck of femur, and to demonstrate if the improved stability seen in previous clinical situations with these designs, can be used to benefit this difficult subgroup of patients that are particularly prone to dislocation.

Forty-six consecutive independent, active and mentally alert patients with displaced intracapsular fractured neck of femur underwent large diameter head uncemented THR. The mean age of patients was 72.1 years. The outcome measures used were the dislocation rate, reoperation and revision rate, Oxford hip score (OHS), EuroQol (EQ-5D) and residential status.

Clinical and radiological data were available on all 46 patients. At a mean follow-up of 12.5 months there were no dislocations. There were no reoperations, revisions or infections. Two patients died (4.3%) from unrelated causes. Mean pre- and postoperative OHS were 12.1 and 17.9 respectively. The mean pre- and postoperative EQ-5D index scores were 0.97 and 0.83 respectively. The mean postoperative walking distance was 2.5 miles and there were no changes in residential status.

This is the first published series utilising a 36-mm diameter metal-on-metal THR for the treatment of fractured neck of femur in mobile, independent patients. We have demonstrated that it affords patients excellent stability with no recorded dislocations.

The aim of this study was to investigate the use of large diameter head THR to treat fractured neck of femur, and to demonstrate if this conferred greater stability.

Forty-six (46) independent, mentally alert patients with displaced intracapsular fractures underwent THR. Mean age was 72.1 years. Outcome measures were dislocation, reoperation/ revision rate, Oxford hip score (OHS), Euroqol (EQ-5D) and residential status. Data was collected prospectively, with review being carried out at 3 months and 1 year.

At mean follow-up (12.5 months) there were no dislocations. Reoperation, revision and infection rate were all 0%. Two patients died (4.3%). Mean pre-injury and postoperative OHS were 12.1 and 17.9 respectively. Mean pre-injury and postoperative EQ-5D index scores were 0.97 and 0.83 respectively. Mean postoperative walking distance was 2.5 miles. There were no changes in residential status.

This is the first published series utilizing 36-mm diameter metal-on-metal THR for the treatment of fractured neck of femur. We have demonstrated that it affords patients excellent stability with no recorded dislocations.

Previously ankylosed or surgically arthrodesed hip joints can be converted successfully to a total hip replacement (THR) in order to improve patient mobility and function. We present a long term prospective cohort study of cementless revisions of previously ankylosed hips.

Sixteen hips (15 patients) with a mean age of 52 years (range 16 to 75) had ankylosed hips for a mean of 36 years (range 3.5 to 65 years). They all received a cementless THR between August 1988 and January 2003 and were prospectively followed-up for a mean of 11 years (range 5.0 to 19 years). Two patients died during the study period of unrelated causes and none were lost to follow-up.

All patients showed improved mobility and function following the conversion of their ankylosed hips. The Harris Hip Score improved from a pre-operative mean value of 70 (Standard Error of Mean (SEM) 3.4) to a post-operative value of 83 (SEM 4.4) at the latest review, which was statistically significant (p < 0.05).

There was one acetabular cup revision at 5 years post implantation for aseptic loosening. At a mean of 11 years post THR, all other femoral and acetabular components remained clinically and radiographically well fixed. One patient with systemic ankylosing spondylitis and spontaneous bilateral bony hip ankylosis developed the unusual complication of Paget’s disease of the left hemipelvis and proximal femur two years after successful bilateral THR surgery. His symptoms resolved following medical therapy for Paget’s disease.

We conclude that a previously ankylosed hip can be effectively converted to a cementless total hip replacement with good long term results.

We evaluated the clinical, radiographic, and functional outcome of uncemented total hip arthroplasty (THA) following vascularized fibular grafting for avascular necrosis (AVN) of the femoral head. A group of twenty-two patients who had been converted from a vascularized fibular graft to THA was compared to a similar group of twenty-two patients who had received a THA with no prior graft. The graft group was found to have worse outcomes than the control group as measured by SF-36, and WOMAC scores, as well as a hip score.

These results show that vascularized fibular grafting complicates future THA.

The Purpose of this study was to evaluate the clinical, radiographic, and functional outcome of uncemented total hip arthroplasty (THA) following vascularized fibular grafting for avascular necrosis (AVN) of the femoral head. These results indicate that functional and clinical outcome following post-graft THA is worse than outcome following THA performed as a primary intervention.

Judicious use of the vascularized fibular graft procedure is critical in order to minimize the number of graft failures and avoid the negative outcomes associated with THA after failed vascularized fibular grafting.

Twenty-six hips in twenty-two patients who had a THA following a failed vascularized fibular graft were compared to a group of twenty-three hips in twenty-two age and sex-matched patients who had received a THA with no prior graft (combined mean age: 39.0 yrs). Primary outcome measures included the SF-36 (patient-based general health assessment – total score and physical sub-component) and WOMAC (patient-based arthritis specific score) scores at matched follow up times (mean: 6.2years, range: two to fourteen years). An objective hip score was also used, as were several radiographic variables. The post-graft group had lower SF-36 final scores (p< 0.006), lower SF-36: physical function scores (p< 0.001), and lower WOMAC scores (p< 0.045) than the control group. Post-graft THA was complicated by longer operative time (p< 0.025) and greater subsidence of the femoral prosthesis (p< 0.004) compared to controls. Additionally, the post-graft group had worse hip score values (p< 0.05) than controls.

Vascularized fibular grafting is a commonly used procedure to cure or delay progression of AVN in the hip. Currently this procedure is used for young (< 40 years) patients with hip AVN who are in an early, pre-collapse stage of the disease. Although the efficacy of vascularized fibular grafting has been proven, up to 29% of grafts fail at five years and need to be converted to THA (Urbaniak et al., 1995). This study shows that THA after failed vascularized fibular grafting has a worse outcome than THA as a primary intervention. Therefore judicious use of the graft procedure is critical in order to minimize the number of graft failures and avoid the negative outcomes associated with it.

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.

Introduction: The use of custom made CAD-CAM femoral stems in primary Total Hip Replacement allows preservation of valuable bone stock in anatomically challenging femora whilst optimising biomechanics and improving function. The custom prosthesis design and manufacturing process is carried out with the aid of computed tomography (CT), a system of tomographic image processing, a Computer–Aided Design (CAD) system and a Computer–Aided Manufacturing (CAM) system.

Aim: To report seven year minimum follow up of a custom made and designed femoral component used in total hip replacement, focusing on clinical and radiographic evidence of failure.

Methods: Patients who had an uncemented total hip arthroplasty, by one of the two senior authors, with a CAD-CAM hip between February 1993 and February 2000 were retrospectively studied. An independent observer evaluated all patients radiologically using Engh’s criteria of osteointegration and clinically using Harris and Oxford Hip Scores.

Results: 85 patients (47 male, 38 female) (102hips) underwent THA for a variety of reasons between February 1993 and February 2000. Average age was 53.7 (25.4–91.5). Average follow up was 9.3 years (7–15). The aetiologies for THA were: Developmental Dysplasia of Hip (22 hips), Osteoarthritis (25), Slipped Upper Femoral Epiphysis (3), Skeletal Dysplasia (11), Trauma (9), Perthe’s Disease (6), Avascular Necrosis (14), Tumour (4) and other (8). At last follow up 4 hips had been revised: 2 for aseptic loosening, 1 for deep infection and 1 for excessive acetabular cup liner wear. 84 patients were evaluated (one deceased from unrelated causes). Average Harris Hip Score was 81 (range 53–96). Average Oxford Hip Score was 24 (range15–43). A full set of x-rays was available for 73 patients and when evaluated all were radiographically stable. Endosteal bone formation or spots welds were present on all 73 of the x-rays. Radiolucent lines at the bone-implant interface were present on 7/73 x-rays but did not correlate with clinical problems. There was no evidence of bone pedestal formation.

Conclusions: Clinical results are good to excellent with little radiographic evidence of failure. CAD-CAM hips can be safely and reliably used for a variety of aetiologies with predictable result at least up to seven years postoperatively.

Introduction: One of the most important factors, to improve the primary prosthesis stability is the bearing surface between the femoral head and the cup. The connection metal-metal and ceramic-ceramic seems to be one of the best to reduce the loosening rate. The purpose of the study is to evaluate the long-term results of uncemented total hip replacement using the ceramic Mittelmeier enoprosthesis (ceramic cup – ceramic head). Material and Methods: In the last twenty years, 258 primary ceramic, Mittelmeier type hip endoprosthesis were implanted in our Institution. This surgery was performed in 222 patients (116 women and 106 men), at the average age at the surgery of 45,6 years (range from 18 years to 70 years). In 36 patients the surgery was performed on both hips. The means follow-up was 10,2 years ( range from 4 years to 18,6 years). The most frequent indication for surgery was: in 105 cases idiopathic, in 81 dyspalstic and in 25 posttraumatic coxarthrosis. All patients were evaluated clinically and radiological. For clinical evaluation the classification system proposed by Merle d’Aubigne and Postel with Charnley modification was used. For radiological evaluation the classification system proposed by De Lee and Charnley ( steam) and system by Gruen and Moreland (cup) was used. Results: Based on above mentioned criteria in 87 hips (33,7%) the final result was graded as very good, in 96 cases (37,3%) as good, in 47 hips (18,2%) as satisfactory and in the remaining 28 cases (10,9%) the final result was poor. The very good and good results were noted in patients older than 50 years with idiopathic coxarthrosis. The poor results were observed in young patients with dysplastic coxarthrosis, especially in cases with poor developed hip joint after the previous hip surgery in the childhood, because of DDH (type III and IV according to Crowe at all. classification system). Only 13 hips (5%) required revision procedures. In 2 cases (0,8%) revision was directed only to the cup, in 6 hips (2,3%) to the steam and in 5 cases (1,9%) it was necessary to exchange both elements. Conclusion: The long term results and our experience with ceramic uncemented hip endoprosthesis type Mittelmeier are promising. This type of hip prosthesis should be indicated in young patients with idiopathic or posttraumatic coxarthrosis. This indication could give long lasting good clinical and functional results

Background

Although the tribological characteristics are excellent, cup fixation has been one of the limitations in alumina-on-alumina total hip replacement (THR), so different types of materials and surfaces have been developing. We analysed the clinical and radiological outcome of two different uncemented cups for the same alumina-on-alumina THR.