The objective of this study was to determine whether the bearing surface is a risk factor for revision after late dislocation in total hip arthroplasty (THA). Data from primary THAs were extracted from the New Zealand Joint Registry over a 13-year period. The mean age of patients was 68.9 years; 53.2% were female. The surgical approach used was posterior in 66% of THAs, lateral in 29% and anterior in 5%. There were 53,331 (65.1%) metal-on-polyethylene THAs, 14,093 (17.2%) ceramic-on-polyethylene, 8,177 (10.0%) ceramic-on-ceramic, 461 (0.5%) ceramic-on-metal, 5910, and (7.2%) metal-on-metal. The primary endpoint was late revision for dislocation, with ‘late’ defined as greater than one year post-operatively. 73,386 hips were available for analysis. The overall revision rate was 4.3% (3,130 THAs), 1.1% (836) were revised for dislocation. Only 0.65% (470) hips were revised for dislocation after the first post-operative year. The unadjusted hazard ratios (HR) showed significantly higher rates of revision for dislocation in ceramic-on-polyethylene (HR 2.48; p=0.001) and metal-on-polyethylene (HR 2.00; 95% p =0.007) compared to ceramic-on-ceramic. However, when adjusted for head size, age and surgical approach, only ceramic-on-polyethylene (HR 2.10; p=0.021) maintained a significantly higher rate of revision, whereas metal-on-polyethylene approached significance (HR 1.76; 95% p = 0.075). In New Zealand, dislocation is the most common reason for revision, ahead of aseptic loosening of the acetabular component. The relationships between bearing materials and risk of revision for late dislocation is controversial. However, in this study ceramic-on-ceramic shows lower risk rates for revision than other bearing surface combinations. Low wear and less debris, limited peri-articular inflammatory reaction and an healthy fibrotic pseudo-capsule are potential factors determining long-term stability of the hip joint

Introduction

Taper corrosion at modular junctions can cause a spectrum of adverse local tissue reactions (ALTR) in the periprosthetic soft tissues in patients who have undergone total hip arthroplasty (THA). Because these reactions are usually painful, taper corrosion has become part of the differential diagnosis of hip pain following THA. However these destructive lesions may not always cause pain, and can occasionally result in other atypical presentations. The purpose of this study is to describe a cohort of patients presenting with late and recurrent instability following THA due to underlying ALTR and taper corrosion.

The number one reason to consider large heads in total hip arthroplasty (THA) is for increased stability. Large diameter femoral heads substantially increase stability by virtue of increased range of motion and increased jump distance, which is the amount of displacement required to sublux the head out of the socket. Prevention is the best means for reducing dislocation, with requisites for stability being appropriate component position, restoration of leg length, and restoration of offset. In a review from our center studying the frequency of dislocation with small diameter femoral heads (≤32 mm) in 1262 patients (1518 hips) who underwent primary THA performed via a direct lateral approach, we observed a dislocation rate of 0.8% (12 of 1518). In a subsequent study of 1748 patients (2020 hips) who underwent primary THA at our center with large diameter heads (mean 43 mm, range 36–60 mm), we observed a substantially lower 0.04% frequency of dislocation (one of 2010) at a mean followup of 2.6 years. Our findings have been echoed in studies from several other centers. Howie et al. reported a prospective controlled trial of 644 low risk patients undergoing primary or revision THA randomised to receive either a 36 mm or 28 mm metal head articulated on highly crosslinked polyethylene. They observed significantly lower frequency of frequency of dislocation with 36 mm heads both overall (1.3%, 4 of 299 versus 5.4%, 17 of 216 with 28 mm heads, p=0.012) and in primary use (0.8%, 2 of 258 versus 4.4%, 12 of 275 with 28 mm heads, p=0.024), and a similar trend in their smaller groups of revision patients (5%, 2 of 41, versus 12%, 5 of 41 with 28 mm heads, p=0.273). Lachiewicz and Soileau reported on early and late dislocation with 36- and 40 mm heads in 112 patients (122 hips) at presumed high risk for dislocation who underwent primary THA. Risk factors were age >75 for 80 hips, proximal femur fracture for 18, history of contralateral dislocation for 2, history of alcohol abuse in 2, large acetabulum (>60 mm) in 6, and other reasons in 14. Early dislocation (<1 year) occurred in 4% (5 of 122), all with 36 mm heads. Late dislocation (>5 years) did not occur in any of the 74 patients with followup beyond 5 years. Stroh et al. compared 225 patients (248 hips) treated with THA using small diameter heads (<36 mm) to 501 patients (559 hips) treated with THA using large diameter heads (≥36 mm). There were no dislocations with large diameter heads compared with 1.8% (10 of 559) with small diameter heads. Allen et al. studied whether or not large femoral heads improve functional outcome after primary THA via the posterior approach in 726 patients. There were 399 done with small heads (<36 mm), 254 with medium heads (36 mm), and 73 with large heads (>36 mm), analyzed pre-operatively, at 6 months, and at 12 months. The authors could not find a correlation between increasing head size and improved function at one year, but observed that dislocation was reduced with large diameter heads. Optimization of hip biomechanics via proper surgical technique, component position, and restoration of leg length and offset are mandatory in total hip arthroplasty. Large heads enhance stability by increasing range of motion prior to impingement and enhancing jump stability

Introduction. Dislocation is one of the leading causes of revision after primary total hip arthroplasty (THA). Polyethylene wear is one of the risk factors for late dislocations (>2 years). It can induce an inflammatory response resulting in distension and thinning of the pseudocapsule, predisposing the hip to dislocation. Alternatively, eccentric seating of the femoral head in a worn out socket may result in an asymmetric excursion arc predisposing the hip to impingement, levering out and dislocation. Highly cross linked polyethylene has a significantly lower wear rate as compared to conventional polyethylene. Incidence of late dislocations has been shown to be significantly greater with conventional polyethylene bearings as compared to ceramic bearings. However, there is no literature comparing the risk of dislocation between ceramic- on- ceramic (CoC) bearings with metal/ceramic- on- cross linked polyethylene (M/CoP) bearings and this was the aim our study. Methods. Data regarding revision for dislocation after primary THA for osteoarthritis (OA) between September 1999 and December 2013 was obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOA NJRR). Revision risk for dislocation was compared between CoC, CoP, and MoP bearings. Only those THAs with 28 mm, 32 mm, or 36 mm heads were included in the study. Results. The numbers at risk (0 years) in the CoC, CoP, and MoP groups were 53,648; 23,746; and 90,040 THAs respectively. The overall revision (dislocation)/100 observed years was 0.13. Revision rate/100 observed years in the CoC, CoP, and MoP groups was 0.12, 0.12, and 0.16 respectively. The cumulative percentage revision for dislocation (CPRD) for the three bearing types is shown in figure 1. The CPRD at 12 years in the CoC, CoP, and MoP groups was 0.9, 1.0 and 1.2 respectively. The rise in CPRD between 2 and 12 years (late dislocations) was 0.4, 0.6, and 0.6 in the CoC, CoP, and MoP groups respectively (Figure 1). The age and gender adjusted hazards ratio (HR) for revision for dislocation in CoC vs. CoP groups was 1.05 (p=0.684, 1month+); in MoP vs. CoP group was 1.45 (p<0.001, entire period) and MoP vs. CoC group was 1.55 (p<0.001, 6 month+). Computation of age and gender adjusted HR comparing the three bearing groups after stratification according to head sizes (28 mm, 32 mm and 36 mm) showed no significant difference in HR after 3 months (p≥0.061). Conclusion. The revision (dislocation)/100 observed years was greater in the MoP group as compared to CoC and CoP groups (MoP > CoC = CoP). The age and gender adjusted HR (revision for dislocation) was significantly greater in the MoP group as compared to CoC and CoP groups after 6 months. However, when the data was stratified according to head sizes, the age and gender adjusted HR was similar between the three bearing groups after 3 months. In conclusion, there is no significant difference in the risk of revision for dislocation between CoC, CoP, and MoP bearings after adjusting for age, gender, and head size after 3 months

The number one reason to consider large heads in total hip arthroplasty (THA) is for increased stability. Large diameter femoral heads substantially increase stability by virtue of increased range of motion and increased jump distance, which is the amount of displacement required to sublux the head out of the socket. Prevention is the best means for reducing dislocation, with requisites for stability being appropriate component position, restoration of leg length, and restoration of offset. In a review from our center studying the frequency of dislocation with small diameter femoral heads (≤32 mm) in 1262 patients (1518 hips) who underwent primary THA performed via a direct lateral approach, we observed a dislocation rate of 0.8% (12 of 1518). In a subsequent study of 1748 patients (2020 hips) who underwent primary THA at our center with large diameter heads (mean 43 mm, range 36–60 mm), we observed a substantially lower 0.04% frequency of dislocation (one of 2010) at a mean followup of 2.6 years. Our findings have been echoed in studies from several other centers. Howie et al. reported a prospective controlled trial of 644 low risk patients undergoing primary or revision THA randomised to receive either a 36 mm or 28 mm metal head articulated on highly crosslinked polyethylene. They observed significantly lower frequency of frequency of dislocation with 36 mm heads both overall (1.3%, 4 of 299 versus 5.4%, 17 of 216 with 28 mm heads, p=0.012) and in primary use (0.8%, 2 of 258 versus 4.4%, 12 of 275 with 28 mm heads, p=0.024), and a similar trend in their smaller groups of revision patients (5%, 2 of 41 versus 12%, 5 of 41 with 28 mm heads, p=0.273). Lachiewicz and Soileau reported on early and late dislocation with 36- and 40 mm heads in 112 patients (122 hips) at presumed high risk for dislocation who underwent primary THA. Risk factors were age >75 for 80 hips, proximal femur fracture for 18, history of contralateral dislocation for 2, history of alcohol abuse in 2, large acetabulum (>60 mm) in 6, and other reasons in 14. Early dislocation (<1 year) occurred in 4% (5 of 122), all with 36 mm heads. Late dislocation (>5 years) did not occur in any of the 74 patients with follow up beyond 5 years. Stroh et al. compared 225 patients (248 hips) treated with THA using small diameter heads (<36 mm) to 501 patients (559 hips) treated with THA using large diameter heads (≥36 mm). There were no dislocations with large diameter heads compared with 1.8% (10 of 559) with small diameter heads. Allen et al. studied whether or not large femoral heads improve functional outcome after primary THA via the posterior approach in 726 patients. There were 399 done with small heads (<36 mm), 254 with medium heads (36 mm), and 73 with large heads (>36 mm), analyzed preoperatively, at 6 months, and at 12 months. The authors could not find a correlation between increasing head size and improved function at one year, but observed that dislocation was reduced with large diameter heads. Optimization of hip biomechanics via proper surgical technique, component position, and restoration of leg length and offset are mandatory in total hip arthroplasty. Large heads enhance stability by increasing range of motion prior to impingement and enhancing jump stability

Purpose. The purpose of this study was to evaluate the complications related to the prosthesis design in patients managed with cemented total knee arthroplasty (TKA) with the anterior-posterior glide (APG) mobile bearing prosthesis. Materials and Methods. One hundred eighty three total knee arthroplasties were performed using APG Low Contact Stress mobile bearing prosthesis (Depuy, Warsaw, IN) on 146 patients with an average of 8.4 years follow-up (range, 7 to 10 years). Patients were evaluated clinically and radiologically according to the American Knee Society clinical scoring system. The anteroposterior translation, anterior soft tissue impingements, and complications were assessed at the follow-up periods. Results. No knee had loosening and measurable polyethylene wear on radiographs. There were late dislocations of bearing in 2 knees (1.1%), anterior soft tissue impingements in 6 knees (3.3%) at an earlier follow-up, abnormal anteroposterior translation in 5 knees (2.7%), and a fracture of the femoral component induced by osteolysis in 1 knee. Two patients with late dislocation of bearing had preoperative varus deformity more than 15° angulations and 20° flexion contracture. Conclusion. An improvement in a restraint mechanism of the APG mobile bearing prosthesis is needed to minimize the development of complications with regard to a combination of this design and patient factors

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

The main causes of total hip arthroplasty (THA) revisions are loosening and instability. Use of a dual mobility cup cemented in a acetabular reconstruction cage device limits the risk of instability and does not hinder the acetabular fixation during THA revisions. The objective of this study was to analyse a retrospective series of 123 THA revisions with antiprotusio cage and dual mobility socket. Patients and methods: At a mean follow-up of 10 years, we analysed a continuous series of 123 revisions using a reconstruction device (87 Kerboull cross-plates, 12 Burch-Schneider antiprotrusio cages, 24 custom-fit Novae ARM cages associated in all cases with a Novae Stick dual mobility cup cemented into the cage). There were 80 women and 43 males. The mean age at the surgery was 69.2 years old. PMA score increased from 9.6 +/− 3.06 preoperatively to 14.2 +/− 2. at the follow-up. 9 early dislocations occurred and one late dislocation. At the last follow-up, the X-rays showed nine hardware failures, including one cross-plate fracture, one hook fracture, and one flange fracture. Analysis of the radiological position of the cup showed a mean lowering of 13 mm and a 7 mm lateralisation compared to the preoperative position. 2 revisions for aseptic loosening and 3 for septic loosening were performed. This study confirms the advantage of dual mobility cups during acetabular reconstruction cemented in antiprotrusio cages as a way to limit, without eliminating, the risk of dislocation. Therefore cemented fixation of dual mobility cups in cages appears to be a reliable short-term option

Introduction. Total hip arthroplasty (THA) instability is well documented to be more common in specific demographic groups. We report a retrospective analysis of the use of a dual mobility implant for primary hip replacements in selected patients at risk for dislocation. The aim of this study was to assess the long-term clinical and radiologic features associated with the dual mobility cup in case of primary THA. Materials and Methods. At our institution 119 primary THA were performed in 114 patients (74 females and 40 males) at high risk of instability between January 2000 and December 2002. 84% of the patients had at least two risk factors for dislocation. The mean age was 71 years old (range, 21.4 to 93.2 years) at the time of the arthroplasty. A dual mobility cup was used in all cases. Clinical result was assessed using Harris Hip Score, and complications were determined by detailed review of the patient's records. Radiographs of the involved joint were reviewed to assess the position of the prosthesis and to look for osteolysis and signs of loosening of the implant. Results. During the study period, 56 patients (47%) died of unrelated causes. 17 patients (15%) were lost to follow-up. For the remaining 41 patients (46 hips, 38%), the minimal follow-up was 10 years (119 to 154 months, mean 133 months). Harris hip score improved from 39.6 to 82.4 (p<0.05). Only one late dislocation was observed, 7 years after the surgery, in a 35-year old female with Mannosidosis. Two hips were revised at latest follow-up, for deep infections. No aseptic loosening of the cup or osteolysis was observed at latest follow-up. Conclusion. The dual mobility system was extremely successful in achieving stability in this continuous series of patients with increased risk for dislocation. In addition, no mechanical failure, and no osteolysis or aseptic loosening of the cup has been reported. The use of dual mobility cup to prevent instability in selected patients is a reliable option at long term follow-up

Different bearing surfaces, including alumina-on-alumina have been used to avoid osteolysis. We ask if the use of modern ceramics matched with metal-backed sockets improves clinical results avoiding aseptic loosening, osteolysis and late dislocations. We prospectively analysed 315 Cerafit cups in two different generations: First generation implanted between 1999 and 2005 (124 cups) and second generation (191 cups) all implanted with a 5-year minimum follow-up, and associated with a Multicone-HAP stem using alumina-on-alumina bearings. Patients' mean age was 48.7+13.6 years. There were three dislocations within the first postoperative month and one early recurrent dislocation requiring reoperation using a double mobility cup. There were four intraoperative fractures, two in rheumatoid juvenile arthritis cases solved with a cerclage, and one postoperative fracture solved using a femoral long-stem. No fractures were seen in the alumina components in this series. Also, there have been no infections. There were 4 patients reporting non-reproducible squeaking. Survivorship analysis for cup loosening for any cause was 93% for group 1 (11 cups) and 99.2% for group 2 (1 cup in a patient with severe developmental dysplasia). The cumulative probability of not having a revision of one or both components for any cause was 96.9% (CI 95%:9.47–99.1%), All unrevised cases showed good clinical and radiographic results at the end of follow-up. No stem loosening, osteolysis nor stress shielding were found in any case by the end of follow-up. Changes in linear femoral head penetration were not seen in any hip. These data suggest that Cerafit alumina-on-alumina prostheses show excellent results after fiften years. Cup loosening was more frequent in the cups of first generation, but not currently. Continued follow-up will be required to determine if reduction in wear between the alumina-on alumina bearings results in less osteolysis and loosening

Dual mobility components for total hip arthroplasty provide for an additional articular surface, with the goals of improving range of motion, jump distance, and overall stability of the prosthetic hip joint. A large polyethylene head articulates with a polished metal acetabular component, and an additional smaller metal head is snap-fit into the large polyethylene. New components have been released for use in North America over the past four years. In some European centers, these components are routinely used for primary total hip arthroplasty. Some surgeons in USA suggest routine use in primary hip arthroplasty. However, their greatest utility is to manage recurrent dislocation in the setting of revision total hip arthroplasty. Recent biomechanical data suggests that, in a 3D CT scan-cadaver hip model, there is no difference in range of motion between a 36mm head and an ADM dual mobility component sizes 50–56mm. There is little wear data on dual mobility components, except from one implant manufacturer. It is feared that there is a “3rd articulation” in dual mobility components—the routine impingement of the femoral neck against the polyethylene femoral head. Several retrospective series have shown satisfactory results for these dual mobility components at short- to medium-term follow-up times. There are important concerns with polyethylene wear, late intra-prosthetic dislocation, and the lack of long-term follow-up data. Big femoral heads (36mm and 40mm) articulating with highly cross-linked, e-beam, remelted, polyethylene are a better choice in primary total hip arthroplasty, to decrease the frequency of dislocation in “high risk” patients. Although the risk of early dislocation was 4% in “high risk” patients, there was no recurrence, no revision, and no late first dislocation. Until further long-term results are available, caution is advised in the routine use of dual mobility components in primary total hip arthroplasty

Hip dislocation is one of the most common causes of patient and surgeon dissatisfaction following hip replacement. To correctly treat dislocation, the causes must first be understood. Patient factors included age greater than 70, medical co-morbidities, female gender, musculo-ligamentous laxity, revision surgery, issues with the abductors and trochanter and education. Issues related to the surgeon and technique are surgical volume and experience, the surgical approach and repair, adequate restoration of femoral offset and leg length, correct component position, and avoidance of soft tissue or bony impingement. There are also implant-related factors. Chief among these is the design of the head and neck region. Is the femoral head diameter sufficient, and in concert with the prosthetic neck is there an adequate head-neck ratio? Skirts on longer neck lengths greatly reduce the head-neck ratio and should be avoided if possible. There must be available offset choices in order to restore soft tissue tension. Lipped liners aid in gaining stability, yet if improperly placed may result in impingement and dislocation. Late dislocation may result from polyethylene wear, soft tissue destruction, trochanteric or abductor disruption and weakness, or infection. Understanding the causes of hip dislocation allow prevention in a majority of instances. Proper pre-operative planning includes the identification of high-offset patients in whom inadequate restoration of offset will reduce soft tissue tension and abductor efficiency. Component position must be accurate to achieve stability without impingement. Finally, patient education cannot be over-emphasised, as most dislocations occur early, and are preventable with proper instructions

Background:. Historically, performing a successful hip joint replacement in patients aged fewer than 30 years has been an orthopedic challenge. The newer generation of prostheses and surgical techniques has the potential to increase the longevity of implants. The purpose of this study was to evaluate the outcomes of cementless hip arthroplasty in patients aged fewer than 30 years. Materials and Methods:. In this cross-sectional study, 41 patients (46 hips) were studied with a mean age of 24, 4 (from 17 to 30 years) of whom underwent cementless metal – polyethylene hip arthroplasty from 2004 to 2007. The Harris hip score (HHS) was used to assess the functional consequences. Patients were followed up in terms of early complications (thrombophlebitis of the lower limbs, dislocation, hematoma and infection) and late complications (aseptic loosening, dislocation, and reoperation) at weeks 3 and 6, at 3 and 6 months, one year after surgery and annually thereafter. Results:. Patients were followed for an average of 5 years and 2 months (from 51 to 82 months). One early complication (symptomatic thrombophlebitis) and one late dislocation (2.2%) were observed. There were no cases of aseptic loosening or osteolysis at the end of follow-up. The preoperative HHS was 59.6 (from 41 to 76), which rose to 82 and 83.5 after the one-year and final follow-up, respectively, which was a significantly increase. Conclusions:. Hip arthroplasty using a new generation of cementless proximal porous prosthesis with resistant polyethylene to cover the joint surfaces in patients aged fewer than 30 years is satisfactory and is accompanied by low complications. Keywords: Total hip replacement, hip arthroplasty, cementless Prosthesis, Hip osteoarthritis, osteonecrosis

Introduction. Alumina-on-alumina in total hip replacement has been used for avoiding osteolysis and loosening. Published series report no ceramic wear and low rates for fractures and noises, but report poor results because of acetabular fixation failure. From 1999 to 2005, we used the “first generation” of a cementless cup, tri-radius relatively-smoothed HA coated (group 1), and from 2006 we have used a “second-generation” of this same cementless cup design with a macrotextured surface (group 2). We compare the perioperative conditions of two groups of patients using these two different cups and the clinical and radiological results. Material and Methods. We analysed 679 (612 patients) consecutive and non-selected primary cementless alumina-on-alumina prostheses. There were 342 hips in group 1 and 337 in group 2. The stem used for all patients in this series was the same and fitted with an Al2O3 liner and femoral head. The use of screws were according to the intraoperative stability of the cup (pull-out test). Patients’ mean age was 48.7+13.6 years and the average follow-up until revision or the last evaluation was 11.7 years for group 1 and 5.4 years for group 2. Results. Group 1, osteopenic and dysplastic acetabulae and women had a higher risk of screw use (p=0.004, p<0.001, p<0.001, p=0.011, respectively). Although the pre-operative clinical score was worse in group 2, the post-operative results were better (p<0.001).). No squeaking was found in any case. No alumina fractures occurred in this series. There was malseating of the liner in three hips, spontaneously resolved at six monthpostsurgery in all cases. No stem loosening, osteolysis or stress shielding were found in any case by the end of follow-up. Changes in linear femoral head penetration were not seen in any hip. There were 17 revised cups due to aseptic loosening, 15 were group 1 and two group 2. The probability of not having cup loosening was 93.3% (95% CI: 89.7 to 96.9) in group 1 and 97.5% (95% CI: 93.5 to 100) in group 2. Cup loosening was more frequent for severe congenital dysplasia of the hip (p<0.001) and in acetabular Dorr’ type C than in other types (p=0.0004). Of the hips revised for aseptic loosening, 6 were inside Lewinnek's safe zone versus 11 cups which was outside this zone (p<0.0001). Multivariate analysis showed that acetabular type C and cups outside Lewinnek´s safe zone had a higher risk for aseptic loosening (p<0.001, HR: 8.088, 95% CI 3.121–20.961; and p=0.003, HR: 5.128, 95% CI 1.773–14.829, respectively). Conclusions. Although the follow-up of this series is too short in the new Cerafit cup to allow definite conclusions, our data suggest that Cerafit alumina-on-alumina prostheses show excellent results after fifteen years. The macrotextured surface of the cup improved fixation compared to the early group Cup loosening was more frequent in severe congenital dysplasia, acetabular Dorr type C and in cups implanted outside of the Lewinnek's safe zone. Continued follow-up is required to determine if reduction in wear between the alumina-on alumina bearings results in less osteolysis, loosening, and late dislocations

Massive proximal femoral bone loss can be a complex problem, despite various modern technical and implant solutions. Due to inadequate bone stock and missing proximal fixation possibilities, including larger segmental osseous defects, the use of a mega prosthesis might become necessary. Coverage of the segmental bone loss in combination with distal fixation, can be achieved in either cemented or non-cemented techniques. Some implant types allow for additional fixation of the gluteal muscles, attached with non-absorbable sutures or synthetic mesh grafts. Although first reports about partial or even complete femoral replacement are available since the 1960's, larger case series or technical reports are rare within the literature and limited to some specialised centers. Most series are reported by oncologic centers, with necessary larger osseous resections of the femur. The final implantation of any mega prosthesis system requires meticulous planning, especially to calculate the appropriate leg length of the implant and resulting leg length. Combination of a posterior hip with a lateral knee approach allows for the enlargement to a total femur replacement, if necessary. The lateral vastus muscle is detached and the entire soft tissues envelope can be displaced medially. After implant and cement removal, non-structural bone might be resected. Trial insertion is important, due to the variation of overall muscle tension intraoperatively and prevention of early or late dislocation. Currently the use of proximal modular systems, including length, offset and anteversion adaption, became the technique of choice for these implant systems. However, just very few companies offer yet such a complete system, which might also be expanded to a total femur solution. We were able to evaluate our Endo-Klinik results of total-femur replacements within 100 consecutive patients in non-infected cases, after a mean follow up time of five years. There we “only” 68% patients without complications, main complications included: 13% revealed a deep infection; dislocation was found in 6%, material failure and consequent breakage in 3%, persistent patellar problems in 2% and finally 1% with peroneal nerve palsy. These results show that a total-femur replacement is associated with a high complication rate, even in non-infected patient cohorts

Introduction. Although pelvic tilt does not significantly change after primary total hip arthroplasty (THA) at a short term, can vary over time due to aging and the possible appearence of sagittal spine disorders. Cup positioning relative to the stem can be influenced due to these changes. Purpose. We assessed the evolution of pelvic tilt and cup position after THA for a minimum follow-up of five years and the possible appearence of complications. Materials and methods. 47 patients underwent same single THA between 2008 and 2012. All were diagnosed with primary osteoarthritis and their mean age was 70.2 years (range, 63 to 75). There were 28 male patients, 19 had a contralateral THA, 17 were studied for lumbar pathology and three were operated for lumbo-sacral fusion. Radiological analysis included sacro- femoral-pubic and acetabular abduction angles on the anteroposterior pelvic view; and cup anteversion angle on the lateral cross-table hip view according to Woo and Morrey. All assessments were done pre-operatively and at 6 weeks, one, two and five years post-operatively. Three measurements were recorded and mean was obtained at all intervals All radiographs were evaluated by the same author, who was not involved in surgery. Results. There were four dislocations: one early and two contralateral dislocations which were solved wiith closed reduction, and one late recurrent dislocation five years after surgery which required cup revision. No other revision surgeries were performed. Mean sacro-femoral pubic angle decreased at all intervals from 60.6º preoperatively, to 60.0º at one year and 58.8 º at five years. This decrease was more significant in female, 63.3º preoperatively to 59.3º, than in male patients, 58.7º to 58.3º at five years. Mean acetabular abduction angle increased from 47.3º at 6 weeks to 48.2º at five years. Mean cup anteversion increased from 24.3º at 6 weeks to 26.4º at one year and 34.3º at five years. Conclusions. Posterior pelvic tilt increased with aging over time, particularly in women. These changes increased cup inclination and anteversion which may result in more dislocations after primary THA

Dual mobility components for total hip arthroplasty provide for an additional articular surface, with the goals of improving range of motion, jump distance, and overall stability of the prosthetic hip joint. A large polyethylene head articulates with a polished metal acetabular component, and an additional smaller metal head is snap-fit into the large polyethylene. New components have been released for use in North America over the past three years. In some European centers, these components are routinely used for primary total hip arthroplasty. However, their greatest utility may be to manage recurrent dislocation in the setting of revision total hip arthroplasty. Several small retrospective series have shown satisfactory results for this indication at short- to medium-term follow-up times. However, there are important concerns with polyethylene wear, late intra-prosthetic dislocation, and the lack of long-term follow-up data. These components are an important option in the treatment of recurrent dislocation in younger patients, revision of failed metal-metal resurfacing, and salvage of failed constrained liners. Until further long-term results are available, caution is advised in the routine use of dual mobility components in primary or revision total hip arthroplasty