This study presents the clinical and radiological results of 62 consecutive acetabular revisions in 58 patients, at a mean of 16.5 years follow-up (15 to 20). The Kaplan-Meier survivorship for the cup with end-point revisions for any reason, was 79% at 15 years (95% confidence interval (CI); 67 to 91). Excluding two revisions for septic loosening at three and six years, and one revision of a well-fixed cup after 12 years in the course of a femoral revision, the survivorship was 84% at 15 years (95% CI; 73 to 95). At review there were no additional cases of loosening, although seven acetabular reconstructions showed radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.7 cm to 1.0 cm) and a cemented cup, is a reliable technique of reconstruction, when assessed at more than 15 years

Introduction. Acetabular cup lucency predicts cup survival. The relationship of subchondral plate removal and cup survival is unclear. Using data from a prospective study conducted between January 1999 and January 2002 we investigated the role of subchondral plate removal in cemented acetabular cup survival at five years. Methods. A number of cemented cups were implanted using antero-lateral and posterior approaches.1400 cups were inserted. 935 cups (67%) were followed up at 5 years and acetabular radiolucency (AR) recorded. Results. F: M ratio was 1.88. The mean age was 66 (range 23–94). 325 cups had AR. AR was commonest in zone 1 (274). 126 cups has AR isolated to zone 1 only. AR ranged from 1–3 mm. Bone surface was clean and dry in 780 cases. High viscosity cement was used in 1391cases. Simplex was the commonest cement used (749) followed by CMW1 (347). Conventional UHMWPE acetabular liner was used in 755 and “Duration” in 644 patients. 719 Exeter cups and 363 flanged cups were inserted. Acetabular roof was decorticated in 844 and cement pressurised in 1269 cups. AR was more common if cement was not pressurised (52/78 not pressurised vs 268/850 pressurised, p=0.000), if subchondral plate was removed (219/561, p=0.002), and if Simplex or CMW1 was used instead of Palacos (p=0.000). AR after subchondral plate removal was equally common in the young and the older patients (>65 years). There was no difference in cup (p=0.55) or pressuriser type (p= 0.45) between those with or without AR. In a logistic regression model only cement pressurisation and type of cement used were predictive of AR (n=895, p=0.000). Subchondral bone removal became insignificant (p=0.443). Discussion. AR was only affected by cement pressurisation and type of cement used. Subchondral plate removal did not prove likely to affect 5 year cup survival

Most published randomised controlled trials which compare the rates of wear of conventional and cross-linked (XL) polyethylene (PE) in total hip arthroplasty (THA) have described their use with a cementless acetabular component.

We conducted a prospective randomised study to assess the rates of penetration of two distinct types of PE in otherwise identical cemented all-PE acetabular components.

A total of 100 consecutive patients for THA were randomised to receive an acetabular component which had been either highly XL then remelted or moderately XL then annealed.

After a minimum of eight years follow-up, 38 hips in the XL group and 30 hips in the annealed group had complete data (mean follow-up of 9.1 years (7.6 to 10.7) and 8.7 years (7.2 to 10.2), respectively). In the XL group, the steady state rate of penetration from one year onwards was -0.0002 mm/year (sd 0.108): in the annealed group it was 0.1382 mm/year (sd 0.129) (Mann–Whitney U test, p < 0.001). No complication specific to either material was recorded.

These results show that the yearly linear rate of femoral head penetration can be significantly reduced by using a highly XLPE cemented acetabular component.

Cite this article: Bone Joint J 2015;97-B:1458–62.

The aims of this study were to examine the repeatability of measurements of bone mineral density (BMD) around a cemented polyethylene Charnley acetabular component using dual-energy x-ray absorptiometry and to determine the longitudinal pattern of change in BMD during the first 24 months after surgery.

The precision of measurements of BMD in 19 subjects ranged from 7.7% to 10.8% between regions, using a four-region-of-interest model. A longitudinal study of 27 patients demonstrated a transient decrease in net pelvic BMD during the first 12 months, which recovered to baseline at 24 months. The BMD in the region medial to the dome of the component reduced by between 7% and 10% during the first three months, but recovered to approximately baseline values by two years.

Changes in BMD in the pelvis around cemented acetabular components may be measured using dual-energy x-ray absorptiometry. Bone loss after insertion of a cemented Charnley acetabular component is small, transient and occurs mainly at the medial wall of the acetabulum. After two years, bone mass returns to baseline values, with a pattern suggesting a uniform transmission of load to the acetabulum.

In 2022, approximately 60% of inserted cups and stems in Sweden utilized cemented fixation. Two predominant brands, Refobacin Bone Cement R and Palacos R+G, both incorporating gentamicin, were employed in over 90% of primary cemented Total Hip Arthroplasties (THAs) between 2012 and 2022. This study investigates whether the choice between these cement types affects the risk of revision. The five most frequently used cemented cups and the three most common stems were studied. Inclusion criteria encompassed hips with non-tumour diagnoses, operated through a direct lateral or posterior incision, featuring a 28–36 mm metal or ceramic head. Outcomes were assessed for cup revisions (n=55,457 Refobacin, 37,210 Palacos), stem revisions (n=51,732 Refobacin, 30,018 Palacos), and all-cemented THAs with either brand (n=45,265 Refobacin, 26,347 Palacos). Kaplan-Meier life tables and hazard ratios (HR) utilizing Cox regression were computed, adjusting for age, sex, diagnosis, implant type, femoral head size, and material. Over a 10-year period, the cumulative percent revision with Refobacin was consistently higher than Palacos in all three analyses (cups: Refobacin 2.4 (2.3–2.5), Palacos 2.1 (2.0–2.2); stems: Refobacin 2.6 (2.5–2.7), Palacos 2.1 (2,0–2,2); all-cemented: Refobacin 3.2 (2.9–3.5), Palacos 2.9 (2.6–3.2)). Both unadjusted and adjusted HR were 13–25% lower with Palacos. In the analysis of all-cemented THAs, the adjusted HR for Palacos was 0.85 (0.76–0.95). Separating revisions into infectious and non-infectious reasons revealed a lower risk of infectious revisions with Palacos in all three analyses (all-cemented: adjusted HR infection 0.66 (0.56–0.78); non-infectious 1.10 (0.94–1.28)). Hips cemented with Refobacin may face an increased risk of infection, potentially due to a smaller release of antibiotics into surrounding tissues. Unaccounted factors like different mixing systems or unknown biases could also influence outcomes, emphasizing the need for further investigation

Total hip arthroplasty (THA) is one of the preferable solutions for regaining ambulatory activity for patients with end-stage osteoarthritis, and the procedure is well developed technically and large numbers of patients benefit from THA worldwide. However, despite the improvements in implant designs and surgical techniques, revision rates remain high, and the number of revisions is expected to increase in the future as a result of the increase in the volume of primary THA and the increase in the proportion of younger, more active patients who are likely to survive longer than their prosthetic implants. In revision THA, associated loss of bone stock in the acetabulum presents one of the major challenges. The aim of the present study was to analyze the clinical and radiographic outcomes and Kaplan-Meier survivorship of patients underwent revision surgeries of the acetabular cup sustaining aseptic loosening. We reviewed consecutive 101 patients (120 hips; 10 men 11 hips; 91 women 109 hips; age at surgery, 66 years, range, 45–85) who underwent acetabular component revision surgery, at a follow-up period of 14.6 years (range, 10–30). For the evaluation of the state of the acebtabulum, acetabular bony defects were classified according to the classification of the AAOS based on the intraoperative findings as follows; type I [segmental deficiencies] in 24 hips, type II [cavity deficiency] in 48 hips, type III [combined deficiency] in 46, and type IV [pelvic discontinuity] in 2. Basically, we used the implant for acetabular revision surgery that cement or cementless cups were for the AAOS type I acetabular defects, cementless cup, or cemented cup with reinforcement device were for type II, cemented cup with reinforcement device were for type III. Follow-up examination revealed that Harris Hip score improved from 42.5±7.8 points before surgery to 76±16.2 points (p<0.05). The survival rates of the acetabular revision surgery with cemented cups, cementless cups, and cemented cups with reinforcement devices were 65.1%, 72.8%, and 79.8%, respectively, however, there was no significant differences between the groups. There were nine cases, which failed in the early stage in the groups of cementless cups and cemented cups with reinforcement devices, because of the instability of the cementless cups or breakage of reinforcement plates caused by inadequate bone grafting. We conclude that the usage of the cementless cups for type I and II acetabular bony defects, and the cemented cups with reinforcement devices for type III bony defects will demonstrate durable long-term fixation in case of adequate contact between acetabular components and host-bone with restoration of bone stock by impaction bone grafting

Introduction. Acetabular revision surgery is challenging due to severe bone defects. Burch-Schneider anti-protrusion cages (BS cage: Zimmer-Biomet) is one of the options for acetabular revision, however higher dislocation rate was reported. A computed tomography (CT)-based navigation system indicates us the planned direction for implantation of a cemented acetabular cup during surgery. A large diameter femoral head is also expected to reduce the dislocation rate. The purpose of this study is to investigate short-term results of BS cage in acetabular revision surgery combined with the CT-based navigation system and the use of large diameter femoral head. Methods. Sixteen hips of fifteen patients who underwent revision THA using allografts and BS cage between September 2013 and December 2017 were included in this study with the follow-up of 2.7 (0.1–5.0) years. There were 12 women and three men with a mean age of 78.6 years (range, 59–61 years). The cause of acetabular revision was aseptic loosening in all hips. The failed acetabular cup was carefully removed, and acetabular bone defect was graded using the Paprosky classification. Structural allografts were morselized and packed for all medial or contained defects. In some cases, solid allograft was implanted for segmental defects. BS cage was molded to optimize stability and congruity to the acetabulum and fixed with 6.5 mm titanium screws to the iliac bone. The inferior flange was slotted into the ischium. The upside-down trial cup was attached to a straight handle cup positioner with instrumental tracker (Figure 1) and placed on the rim of the BS cage to confirm the direction of the target angle for cement cup implantation under the CT-based navigation system (Stryker). After removing the cement spacer around the X3 RimFit cup (Stryker) onto the BS cage for available maximum large femoral head, the cement cup was implanted with confirming the direction of targeting angle. Japanese Orthopedic Association score (JOA score) of the hip was used for clinical assessment. Implant position, loosening, and consolidation of allograft were assessed using anterior and lateral radiographies of the pelvis. Results. Fifteen hips had a Paprosky IIIB defect, and one hip had a pelvic discontinuity. JOA score significantly improved postoperatively. No radiolucent lines and no displacement of BS cage could be found in 9 of 15 hips. Consolidation of allografts above the protrusion cage was observed in these patients. Displacement of BS cage (>5mm) was observed in 6 hips and displacement was stopped with allograft consolidation in 5 of 6 hips. The other patient showed lateral displacement of BS cage and underwent revision surgery. Average cup inclination and anteversion angles were 37.7±5.0 degree and 24.6±7.2 degree, respectively. 12 of 16 patients were included in Lewinnek's safe zone. One patient with 32 mm diameter of the femoral head had dislocation at 17 days postoperatively. All patients who received ≥36mm diameter of femoral head showed no dislocation. Conclusions. CT-based navigation system and the use of large femoral head may influence the prevention of dislocation in the acetabular revision surgery with BS cage for severe acetabular bone defects

Introduction. Biological repair of acetabular bone defects after impaction bone grafting (IBG) in total hip arthroplasty could facilitate future re-revisions in case of failure of the reconstruction again using the same technique. Few studies have analysed the outcome of these acetabular re-revisions. Patients and Methods. We analysed 34 consecutive acetabular re-revisions that repeated IBG and a cemented cup in a cohort of 330 acetabular IBG revisions. Fresh-frozen femoral head allografts were morselized manually. All data were prospectively collected. Kaplan-Meier survivorship analysis was performed. The mean follow-up after re-revision was 7.2 years (2–17). Intraoperative bone defect had lessened after the first failed revision. At the first revision there were 14 hips with Paprosky 3A and 20 with Paprosky type 3B. At the re-revision there were 5 hips with Paproky 2B, 21 with Paprosky type 3A and 8 with type 3B. Lateral mesh was used in 19 hips. Results. The mean Harris Hip Score improved from 45.4 (6.7) to 77.1 (15.6) at final follow-up. The radiological analysis showed cup migration in 11 hips. The mean appearance time was 25 months (3–72). Of these, migration in three cups was progressive and painful requiring re-revision. Cup tilt was found in all migrated hips. There were one dislocation requiring a cemented dual mobility cup associated with IBG and one infection resolved with resection-arthroplasty. Survival with further cup revision for aseptic loosening was 80.7% (95% Confidence Interval 57.4–100) at 11 years. In all surviving re-revisions trabecular incorporation was observed without radiolucent lines. Conclusion. Biological repair can be obtained by restoring the bone stock, even after successive acetabular reconstructions using IBG and a cemented cup

Introduction. Acetabular component loosening has been one of the factors of revision of total hip arthroplasty (THA). Inadequate mechanical fixation or load transfer may contribute to this loosening process. Several reports showed the load transfer in the acetabulum by metal components. However, there is no report about the influence of the joint surface on the load transfer. We developed a novel acetabular cross-linked polyethylene (CLPE) liner with graft biocompatible phospholipid polymer(MPC) on the surface. The MPC polymer surface had high lubricity and low friction. We hypothesized the acetabular component with MPC polymer surface (MPC-CLPE) may reduce load transfer in the acetabulum compared to that of the by CLPE acetabular component without MPC. Methods. We fixed the three cement cup with MPC-CLPE (Group M; sample No.1–3) and three cement cup with CLPE (Group C; sample No.4–6) placed in the synthetic bone block with bone cement with a 0.10mm thick arc-shaped piezoresistive force sensor, which can measure the dynamic load transfer(Tekscan K-scan 4400; Boston). (Fig 1) A hip simulator (MTS Systems Corp., Eden Prairie, MN) was used for the load transfer test performed according to the ISO Standard 14242-1. Both groups had same inner and outer diameter s of 28 and 50mm, respectively. A Co–Cr alloy femoral head with a diameter of 28 mm (K-MAXs HH-02; KYOCERA Medical Corp.) was used as the femoral component. A biaxial rocking motion was applied to the head/cup interface via an offset bearing assembly with an inclined angle of +20. Both the loading and motion were synchronized at 1 Hz. According to the double-peaked Paul-type physiologic hip load, the applied peak loads were 1793 and 2744 N described in a previous study. The simulator was run 3 cycles. We recorded both the peak of the contact force and the accumulation of the six times load in total. Secondly, we calculated the mean change of the load transfer. We used the Student t-test. P value < 0.05 was used to determine statistical significance. We used EZR for statistical analysis. Results. The mean of total accumulation of the load transfer in the group M is significantly lower than that of in the group C. (7037±508 N vs 11019±1290 N, P<0.0001). The peak of load in the group M was also significantly lower than that in the group C. (1024±166 N vs 1557±395 N) (Fig 2)The mean of the change of the load transfer in the group M is significantly lower than that of in the group C. (2913±112 N vs 4182±306 N) (Fig 3). Conclusion. The acetabular component with MPC surface could reduce and prevent the radical load transfer change toward to the acetabulum compared to CLPE acetabular component without MPC. For any figures or tables, please contact the authors directly

Trabecular metal (TM) augments are designed to support an uncemented socket in revision surgery when adequate rim fit is not possible. We have used TM augments in an alternative arrangement, to contain segmental defects to facilitate impaction bone grafting (IBG) and cementation of a cemented socket. However, there is a paucity of literature supporting the use of this technique. We present one of the largest studies to date, reporting early outcomes of patients from a tertiary centre. A single-centre retrospective analytical study of prospectively collected data was performed on patients who had undergone complex acetabular reconstruction using TM augments, IBG and a cemented cup. All patients operated between 2015 and 2019 were included. We identified 105 patients with a mean age of 74yrs. The mean follow-up was 2.3 years(1–5.5yrs). Our primary outcome measure was all-cause revision of the construct. The secondary outcome measures were, Oxford hip score (OHS), radiographic evidence of cup migration/loosening and post-op complications. Eighty-four out of 105 patients belonged to Paprosky grade IIb, IIc or IIIa. Kaplan-Meier survivorship for all-cause revision was 96.36% (CI, 90.58–100.00) at 2 years with 3 failures. Two were due to early infection which required two-stage re-revision. The third was due to post-operative acetabular fracture which was then re-revised with TM augment, bone graft and large uncemented cup. Pre-op and post-op matched OHS scores were available for 60 hips(57%) with a mean improvement of 13 points. Radiographic analysis showed graft incorporation in all cases with no evidence of cup loosening. The mean vertical cup migration was 0.5mm (Range −5 to 7mm). No other complications were recorded. This study shows that reconstruction of large acetabular defects during revision THA using a combination of TM augments to contain the acetabulum along with IBG to preserve the bone stock and a cemented socket is a reliable and safe technique with low revision rates and satisfactory clinical and radiographic results. Long term studies are needed to assess the possibility of preservation and regeneration of bone stock

We assessed polyethylene wear and osteolysis in 15 patients (30 hips) undergoing staged bilateral total hip arthroplasty, who had a cemented hip arthroplasty on one side and a hybrid arthroplasty on the other. All factors apart from mode of acetabular component fixation were matched. Wear was measured radiographically using Livermore’s technique. The mean clinical and radiological follow-up was 11.2 years for the cemented arthroplasties and 10.7 years for the hybrid arthroplasties. Mean annual linear wear rate for the cemented cups was 0.09mm/year, and 0.14mm/year for the uncemented cups. This difference was statistically significant (p=0.03), confirming previous reports that polyethylene wear in uncemented cups is greater than in cemented cups. Polyethylene wear in the uncemented cup exceeded wear in the cemented cup by more than > 0.1mm/year in 5 patients, 4 of whom had a BMI of greater than 30. No periacetabular osteolysis was noted. Femoral osteolysis was present in 5 hybrid arthroplasties and 2 cemented arthroplasties. Zone 7 femoral osteolysis occurred in 3 patients on the side of the hybrid arthroplasty, multifocal femoral osteolysis not involving zone 7 was seen in 2 patients in both hips

Introduction and Aims: To determine whether polyethylene wear is different comparing cemented polyethylene cups with metal-backed cups and a polyethylene insert. Method: A sample of patients who had hip replacements between February 1995 and July 2002 have been studied. They were randomly allocated to either a cemented polyethylene cup or a metal-backed press-fit cup and polyethylene insert. All patients had a cemented stem and a 28mm ceramic head inserted. Ninety-one patients were treated, and 83 are available for analysis. The pre-operative diagnosis in all was unilateral osteoarthritis. The trial is a prospective randomised one and patients have been assessed clinically and radiologically annually. Twenty-eight patients with cemented polyethylene cups and 55 patients with uncemented metal-backed cups have been analysed. The polyethylene thickness of the cemented cups is 9.6mm on average, and the metal-backed cups had an average liner thickness of 8.9mm. Wear measurements were done using the Martell computer system. Results: Based on measurements done on acetabular cups with the longest follow-up, the metal-backed cups have an average wear of 0.65mm, with an annual wear rate of 0.14mm. The cemented cups have an average wear of 0.64mm, with an annual average of 0.12mm. The study is ongoing and data will be updated. Conclusion: Wear measurements were done using the three-month post-operative x-ray as the baseline and the most recent follow-up x-ray. Based on measurements done on cups with the longest follow-up, there is very little difference between the two groups. The study is ongoing and data will be updated

Reconstruction and revision of the acetabulum component in loose hip implants may be conducted with several techniques, depending on the entity of the defects and of the surgeon’s experience. Impaction grafting with cemented cups or associated to rings or non cemented cups with flanges are some of the options. Rings or cages may have a containment effect but usually do not osteo-integrate. Since 2001 we performed 28 acetabular revisionswith trabecular tantalum metal cups (Zimmer) for Paprosky type II and IIId efects. All the patients but three needed fresh frozen morcellized allograft. Eight patients had less than 50 years; twelve had a previous acetabular fracture that ended in an improper reduction or an infection.Three had a previous infected joint implant, one an infected non-union; this group before the definitive reconstruction had one to three débridement procedures. Six patients without infection had three to six previous surgeries including hip reconstruction. Medial containment disks were used in six patients, to contain bone defects. All patients had a trabecular metal cup fixed with screws or stabilized with press fit alone , associated to a cemented poly cup. Dislocations were not observed. The cemented cup was oriented to overcorrect the head coverage only in four cases. Three patients had a high hip center, but only one has shorter limb. At short follow up no lyseswere observed with adequate osteointegration. Infection did not recurred in any patient. TMT cups simplify complex reconstructive procedures, and in spite of cementing a poly cup, osteointegration occurred in all patients. Lysis was readable in three patients but it was marginal and restricted. Great attention should be kept when an additional hole is done in the cup to confine metal dissemination to the soft tissues

The advantages of high viscosity Simplex AF cement (PMMA) compared to low viscosity Simplex P are the low porosity, the high fatigue strength, the lower polymerization time, and the lower maximum polymerization temperature. A prospective, randomized, double-blind clinical study was conducted to assess the in vivo effects of viscosity of bone cement on the micromotion of a polished tapered stem and UHMWP-cup (Exeter, Stryker-Howmedica). Roentgen Stereophotogrammetric Analysis (RSA-CMS, Medis, The Netherlands) was used to measure micromotion. Twenty patients were included in a Simplex AF group (70 ± 4.3 years), and twenty patients were included in a Simplex P group (71 ± 7.3 years). No significant differences in body mass index and clinical hip scores were observed between the two studied groups. There was no significant difference of the subsidence of both high and low viscosity cemented Exeter stems. The subsidence was according to the literature and showed that the viscosity of the bone cement did not influence the cement-implant bond of this polished tapered stem design. The total migration of the cups and the migration along the medial-lateral axis were significantly larger for the Simplex AF cemented cups compared to the Simplex P cemented cups (p=0.037). This can be explained by the higher cement mantle thickness in acetabular Gruen zone 2 (p=0.003) and 3 (p=0.004) of the Simplex AF cemented cups. We conclude from this study that the viscosity of the bone cement has no effect on the subsidence of polished tapered stems and that a high cement mantle thickness around an UHMWP-cup has a negative effect on fixation

Introduction. There is sparse evidence regarding the survivorship beyond 20 years of both uncemented and cemented hip replacements in patients 50 years and under. We report a unique series reviewing 20–26 year follow-up of patients ≤50 years with cemented Exeter THR. Materials and Methods. We reviewed the survivorship with clinical and radiological outcomes of 138 consecutive cemented THR's in 113 patients ≤50 years. The pre-op diagnoses included Osteoarthritis (30%), DDH (25%), RA (9%) and Post traumatic OA (5%), and 31% of patients had previous surgery to the hip. All patients were followed up at 5 year intervals and there was no patient lost to follow up. Results. Mean age of the patients at the time of surgery was 41.6 (18–50) years. Mean follow up time was 21.6 (20–26) years. There were 93 survivors and 14 deceased patients, with 31 patients needing revision THR. The reasons for revision surgery included 28 cases revised for aseptic loosening of the cup, one patient with Gaucher's disease who developed localised lysis around the stem, one broken stem, and one case with infection. There were no cases of aseptic loosening of the Exeter stem. There were no radiologically loose stems in the surviving or deceased patients at the time of follow-up although 2 patients had radiological evidence of loosening of the cemented cup. Survivorship at 22 years was 75% at for revision for all causes and 98 % for revision of the stem aseptic loosening or lysis. Conclusion. The Exeter cemented THR performs very well in the young patient population, with very favourable survivorship of the Exeter stem in particular, though with less favourable survivorship of these historic cemented cups. This study provides good evidence for the increased use of the cemented Exeter stem in this population group

Introduction. The THR is the second most successful and cost-effective surgical procedure of all time. Data shows that hip cup failure is a significant problem. The aim of this study is to improve methods of cemented cup fixation through validation experiments and FEA. Methods. Five Sawbones composite pelves with cemented UHMWPE cups were tested. Each pelvis was instrumented with triaxial strain gauges at four locations of predicted high strain. Each sample (n = 5) was bolted at the sacroiliac joint in a uniaxial testing machine. A load of 500 N was applied in the direction of the peak force during normal walking, for five repetitions. The directional surface strains were used to evaluate the equivalent strain. Specimen specific finite element models were developed based on CT scan data using ScanIP. Each mesh consisted of an average of 2.5 million linear tetrahedral elements and was solved in ANSYS. Results. The experimentally measured strains were compared against the finite element predictions. The mean linear gradients and SD of the mean at each gauge location were: 1.00 (16%), 0.78 (17%), 0.90 (13%) and 1.05 (4%). Discussion. The agreement between the predicted and experimental equivalent strains was good, but varied across the population. This was caused by the variation in mechanical properties between specimens, and the sensitivity of the gauges to location (steep surface strain gradients). This is most evident with the second strain gauge (0.78, 17%), which is at a suboptimal location. This specific methodology of conducting finite element analyses of the pelvis based on CT image data has been validated. The same methodology has been used to develop a patient specific FEA model, including a bone remodelling algorithm and muscle forces, based on the CT images from the Virtual Human Project. This model is currently being used to optimize the cemented fixation and will be verified experimentally using composite pelves. This research is aimed at informing clinical practice and enhancing long-term cemented fixation. Reducing the need for revision surgery will greatly improve patient quality of life, whilst also reducing the burden on the healthcare delivery system

Introduction. Despite evidence of long term survival of cemented femoral stem prostheses, studies have shown concerns in the longevity of the cemented sockets. This has led to a rise in the use of uncemented and hybrid implants (with uncemented cup and cemented stem) without long term studies to determine evidence for their use. We aimed to assess whether there is any difference in clinical outcome between cemented and non-cemented acetabular fixation in elderly patients. Patients and Methods. Between February 2001 and August 2006 186 patients over 72 years of age were prospectively randomised to receive either a cemented Exeter cup or a HA coated press fit cementless cup. Both groups received a cemented Exeter stem. The patients were assessed pre-operatively and reviewed at 6 weeks, 6 months and yearly in a research clinic, by an independent observer. Outcome measures were the Merle D'Aubigné, Postel, Oxford Hip and Visual analogue pain scores. The implants were also assessed radiographically and all complications were recorded. Results. During the trial 97 patients (mean age 79.13, range 72-90) were randomised to receive a cemented cup (60 right: 37 left) and 89 (mean age 77.65, range 72-95) an uncemented ABG II cup. There was a mean follow-up of 57.6 months (max 9 years) . Statistically there was no significant difference between the two methods of acetabular fixation in outcome measures but radiologically there was a significant difference in wear and loosening (p< 0.001) with cemented cups wearing at a mean of 0.35mm/yr and uncemented cups 0.08mm/yr. Conclusion. Both methods of fixation were demonstrated to have a good outcome with low complication rates. There would appear to be a significant difference in wear rate and osteolysis in this age group between the methods of fixation up to 9 years

Although cement in cement acetabular revision is a recognised option in the presence of a well-fixed cement mantle, partial cement mantle retention is not normally recommended or practiced. However, when revising a cemented acetabular cup it is not infrequent to be faced with loose superolateral cement but well-fixed medial cement. Removal of the well-fixed cement can be time consuming and destructive. An alternative would be to retain this cement and incorporate it into the reconstruction. This study assesses the practice and results of partial cement mantle retention (PCR) at acetabular revision. We retrospectively identified a cohort of 28 hips in 26 patients using the PCR technique from 1. st. January 2000 to 1. st. January 2013. This represented 3.3% of cup revisions where a cemented cup was used. The area of cement loss was reconstructed in one of three ways: re-cementing into drill holes (6 cases); impaction grafting of the defect (8 cases); or use of a trabecular metal wedge (14 cases). 24 hips had a minimum 2-year follow up (mean 6 years). There were no subsequent revisions for aseptic loosening. One acetabulum was later revised for dislocation and X-rays were lost in one patient leaving 22 patients with x-ray available and retained implants. Two of these cases showed progression of lucent lines, which were not clinically significant. Retaining well-fixed medial cement during socket revision appears to be a reasonable reconstruction option in carefully selected cases

We selected randomly a consecutive series of 162 patients requiring hip replacement to receive either a cementless, hemispherical, modular, titanium acetabular cup or a cemented, all-polyethylene cup. These replacements were performed by two surgeons in four general hospitals. The same surgical technique was used and a 26 mm metal-head femoral component was used in every case. After exclusions, 115 hips were studied for differences in rates of wear and osteolysis. The mean clinical follow-up was eight years and the mean radiological follow-up, 6.5 years. The cementless cups wore at a mean rate of 0.15 mm per year and the cemented cups at 0.07 mm per year. This difference was significant (p < 0.0001). Our findings in this mid-term study suggest that cementless cups wear more than cemented cups

Background: According to the mid-term results obtained from the previous registry-based studies, survival of cementless stems for aseptic loosening in younger patients with primary osteoarthritis has been better than the survival of cemented stems. However, it has not been clear if the endurance against aseptic loosening of cementless cups is comparable to that of cemented cups. The aim of the present study was to analyze population-based long-term survival rates of the cemented and cementless total hip replacements in patients under the age of fifty-five years with primary osteoarthritis in Finland. Patients and Methods: Between 1980 and 2006, a total of 7310 primary total hip replacements performed for primary osteoarthritis in patients under the age of fifty-five years were entered in the Finnish Arthroplasty Registry. 4,032 of them fulfilled our inclusion criteria and were subjected to analysis. The implants included were classified in one of the three following groups: implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group #1); implants with a cementless, anatomic, proximally circumferentially porous-coated and/ or hydroxyapatite-coated stem with a porous-coated and/or hydroxyapatite-coated press-fit cup (cementless group #2); and a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Results: Cementless total hip replacements, as well as cementless stems and cups analyzed separately, had a significantly reduced risk of revision for aseptic loosening compared with cemented hip replacements. The 15-year survivorship of cementless stem groups for aseptic loosening was higher than that of cemented stems (89% and 90% vs. 72%). The 15-year survivorship of cementless press-fit porous-coated cups for aseptic loosening was higher than that of cemented cups (80% vs. 71%). When revision for any reason was the end point in survival analyses, however, there were no significant differences among the groups. Conclusions: Both cementless stems and cementless cups have better resistance to aseptic loosening than cemented implants in long term follow-up in younger patients. Even if liner-exchange revisions are taken into account, the long-term survival of cementless total hip replacements is comparable to that of cemented implants