Background. A few patients undergoing a total hip replacement need a subsequent revision of the cup. In some of these cases, the treating surgeon may be confronted with Unexpected Positive Intraoperative Cultures (UPIC). The exact incidence of this finding is unclear. Moreover, it is unknown what the clinical outcome of these patients is when the stem is left in situ. The aim of our study was to describe the incidence of UPIC in patients undergoing cup revision and to determine the need for total revision in this patient group during follow-up. Methods/design. In this retrospective multicenter cohort study, we included all consecutive patients that underwent a cup revision between 2015–2017 and had a minimal follow-up of 2 years. Patients were divided in 3 cohorts: i) no positive intra operative cultures; ii) one UPIC; iii) two or more UPIC. Cases in whom 2 or fewer cultures were obtained during cup revision were excluded from the analysis. Results. From the 334 evaluated cases, 77 were excluded because an inadequate number of cultures were obtained. From the total of 257 included cases, the incidence of UPIC was 16% (n=39). 21 cases had one (8%), and 18 cases had two or more UPIC (7%). After two years of follow up, implant survival in the no UPIC group was 88% (95% CI 0.83 – 0.93), in the one UPIC group 95% (95% CI 0.86 – 1.0), and in the two or more UPIC group 77% (95% CI 0.57 – 0.97). Survival analysis showed no statistically significant differences between the cohorts as determined by cox regressive analysis and log rank test (P = 0.19). Conclusion. The incidence of UPIC in patients who undergo cup revision is relatively high but does not seem to have a major influence on the need for total revision of the hip during a follow-up of 2 years

Purpose. Cementless cup with structural allograft is one of option for acetabular revision in the cases which has severe bone loss. This study was performed to verify that the structural allograft with cementless cup could be one of good options for revision of acetabular cup with severe bone defect and to verify that the allograft resorption affect the stability of cementless acetabular cup. Materials and Methods. We reviewed 25 cases of 25 patients who underwent acetabular cup rvision using cementless porous coated hemispherical cup with structural allograft from May 1992 to July 2011 July 2011. There were nine males and sixteen females with an average age of 50.0 years. The average follow-up period was 76.7(28∼212) months. The clinical evaluation was performed using Harris Hip Score(HHS) and UCLA activity score. Radiologically, the degree of resorption of grafted bone, incorporation of allograft bone with normal bone, osteolysis and cup loosening were evaluated. Results. Clinically, the average Harris hip score was improved from 54 preoperatively to 93.4 at the last follow-up. The average UCLA activity score was also improved from 4.3 preoperatively to 6.4 at the last follow-up. Radiologically, the incorporation of allograft was accomplished in 11.4 months and the resorption of grafted bone was noted in 3 cases(12%), but the allograft resorption had not progressed to moderate degree even in long term follow-up. There was no cup loosening and average survivor rate was 100% in 6 years. There was no infection, allograft nonunion, osteolysis. Conclusion. Cementless cup with structural allograft in acetabular cup reconstruction can provide excellent mi-term results in both clinical and radiological aspects. Structural allograft can provide strong mechanical support for the bone ingrowth of cementless cup. The clinical result of this study auggest that cementless cup with structural allograft can be a good option for acetabular cup revision with severe bone defect. Resorption of structural allograft rarely occurred, and the resorption of structural allograft does not affect stablility of cup even in long term follow-up

Purpose

To assess acetabular component fixation by bone ongrowth onto a titanium plasma sprayed surface as used in revision total hip arthroplasty. Acetabular bone defects, a common finding in revision surgery, and their relation to outcome were also investigated.

Introduction

To report the short to medium term results of acetabular reconstruction using reinforcement/reconstruction ring, morcellised femoral head allograft and cemented metal on metal cup.

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

Objectives. Total hip replacement is increasingly being conducted in younger and more active patients, so surgeons often use bearing surfaces with improved wear characteristics, such as ceramic on ceramic. The primary objective of this study was to determine if survivorship for a BIOLOX® delta ceramic on delta ceramic couple used with the PROCOTYL® L acetabular cup is significantly different from all other cementless cups in a large arthroplasty registry. The secondary objective of this study was to analyze patient reported outcomes measures (PROMs) of the subject cup with a minimum five year follow-up. Methods. Patient demographics and survivorship data was collected from the National Joint Registry of England, Wales, Northern Ireland, and the Isle of Man (NJR) database for all total hip replacements performed with the PROCOTYL® L cup used in combination with a delta-on-delta articulation, as well as for all other cementless cups. Survivorship data was compared for all revisions and cup revisions only and data was adjusted to exclude metal on metal articulations. The hazard ratio of the subject system to all cementless cups was also calculated with the Cox Proportional Hazards model. Patients with the subject components implanted for a minimum of five years completed Oxford Hip, EQ-5D, and EQ VAS score questionnaires. Results. The patient demographic data collected for the subject components and all cementless cups is provided in Figure 1. Six-year survivorship for the subject cup (98.6%) was similar to survivorship for all cementless cup revisions in the NJR database (98.5%), as seen in Figure 2. When the cup alone was revised, six-year survivorship of the subject cup (98.6%) and all NJR cementless cups (98.5%) was also similar. However, the subject cup survivorship remained at 98.6% from 4 to 6 years post-implantation, while survivorship for all cementless cups decreased slightly from years 4 to 6. The similarities between the revision risk of the subject system and all cementless cups in the NJR can be seen in the Cox Proportional Hazards model for revision risk ratios provided in Figure 3. Patients with the subject cup implanted for an average of 5.88 years reported Oxford Hip, EQ-5D, and EQ VAS scores of 39.60 ± 10.78, 0.801 ± 0.259, and 75.49 ± 19.25, respectively. Conclusions. The subject acetabular cup with a ceramic on ceramic articulation exhibited similar survivorship to all other cementless acetabular cups, excluding those with metal on metal bearings, in the NJR. Patients implanted with the subject system for an average of 5.88 years reported what are considered satisfactory Oxford Hip, EQ-5D, and EQ VAS scores. This survivorship and PROMs data is the first report of mid-term outcomes with the subject components

Introduction. Pelvic tilt can vary over time due to aging and the possible appearance of sagittal spine disorders. Cup position in total hip arthroplasty (THA) can be influenced due to these changes. We assessed the evolution of pelvic tilt and cup position after THA and the possible appearance of complications for a minimum follow-up of ten years. Materials and methods. 343 patients received a cementless THA between 2006 and 2009. All were diagnosed with primary osteoarthritis and their mean age was 63.3 years (range, 56 to 80). 168 were women and 175 men. 250 had no significant lumbar pathology, 76 had significant lumbar pathology and 16 had lumbar fusion. Radiological analysis included sacro-femoral-pubic (SFP), acetabular abduction (AA) and anteversion cup (AV) angles. Measurements were done pre-operatively and at 6 weeks, and at five and ten years post-operatively. Three measurements were recorded and the mean obtained at all intervals. All radiographs were evaluated by the same author, who was not involved in the surgery. Results. There were nine dislocations: six were solved with closed reduction, and three required cup revision. All the mean angles changed over time; the SFP angle from 59.2º to 60º (p=0.249), the AA angle from 44.5º to 46.8º (p=0.218), and the AV angle from 14.7º to 16.2º (p=0.002). The SFP angle was lower in older patients at all intervals (p<0.001). The SFP angle changed from 63.8 to 60.4º in women and from 59.4º to 59.3º in men, from 58.6º to 59.6º (p=0.012). The SFP angle changed from 62.7º to 60.9º in patients without lumbar pathology, from 58.6º to 57.4º in patients with lumbar pathology, and from 57.0º to 56.4º in patients with a lumbar fusion (p=0.919). The SFP cup angle was higher in patients without lumbar pathology than in the other groups (p<0.001), however, it changed more than in patients with lumbar pathology or fusion at ten years after THA (p=0.04). Conclusions. Posterior pelvic tilt changed with aging, influencing the cup position in patients after a THA. Changes due to lumbar pathology could influence the appearance of complications at mid and long-term

Hemispheric, porous-ingrowth revision acetabular components (generally with multiple screw fixation) have demonstrated versatility and durability over 25 years. Jumbo cups (minimum diameter of 62mm in women, 66mm in men, or 10mm larger than the normal contralateral acetabulum) are utilised in the majority of revisions with acetabular bone loss, with or without bone grafting, or other augmentation. The popularity of jumbo cups is due to their relative ease of use and the reliability of the result. With up to 20-year follow-up, and failure defined as cup revision for aseptic loosening or radiographic evidence of loosening, implant survival was 97.3% (95% confidence interval, 89.6% to 99.3%) at ten years and 82.8% (95% CI, 59% to 97.6%) at fifteen years. Twenty-year survivorship with 88% free from aseptic loosening of the metal acetabular component has been reported. Instability is decreased in association with larger diameter bearings. Revisions associated with wear of non-crosslinked polyethylene increased in the second decade. Crosslinked polyethylene and ultra-porous materials will likely increase both the durability and the utility of jumbo cups

Introduction. Rottinger published a description of an anterior muscle sparing approach to the hip. It utilizes the same muscle interval as the classic WatsonJones approach between the gluteus medius laterally and tensor fascia lata medially. However, this technique has the disadvantage of needing asplit table and a sterile bag to mobilize the operative leg as extension, adduction and external rotation are the key points for femoral preparation. This study describes our experience for an equivalent of the Watson Jones approach with a simplified technique for the femoral preparation. Material and Methods. Incision starts 1cm distal and 3cm posterior to the ASIS and continues distally for about 8–10 cm along the straightline joining the lateral edge of the patella. It can be extended proximally or distally if necessary. The surgeon is placed posteriorly and the assistant anteriorly. The hip is dislocated with extension and external rotation to osteotomize the femoral neck. During the preparation of the acetabulum the femur is pushed posteriorly with internal rotation. Steinman pins are placed around the acetabulum to improve visualization for reaming and implanting theacetabular components. The femur is then exposed in a simplified way. The operated limb remains on the table. It is adducted above the contralateral limb and rotated outward to allow the femoral metaphysis to protrude. The foot is placed on the edge of the table beside the assistant, the knee is maintained with 45° flexion. The hip capsule is released postero-laterally to improve the femur exposure using Hohman retractors without cutting the short external rotator muscles. Femoral preparation is performed in this position. Once the appropriate implant is selected, the desired head trials are placed. The hip is reduced and the length and stability can be checked with the leg free. In case of isolated cup revision, the femoral head can be conserved. In case of femoral revision, a femorotomy can be easily performed due to the possibility of extended and stable exposure of the femur. Table 1 summarizes the main data of the series. Results. Mean operative duration was 57mn for primary THP (SD 10mn) and 124mn for revisions (SD 28mn). Table 2 summarizes the main complications according to the time line after the first implantation. High BMI patients and exposure of the acetabulum were never a problem; moreover this technique is very attractive for isolated cup revisions. Complications were mainly focused on femoral preparation due to a suboptimal use of the retractors for the exposure (4/13 fracture cases). Poor bone quality (old patients) was responsible for the 9 additional fractures. False route were observed in 4 curved femurs. 3 nerve compressions were due to excessive pressure on the knee by the assistant. Using short stems facilitates femoral exposure and reduces operative time. Conclusions. Hip approaches have been modified throughout the years in attempts to improve patient outcomes. This simplified technique did not induceunusual morbidity or mechanical problems. The benefit in terms of operative time and complications is significant in comparison with our previous experience using a fracture table. To view tables/figures, please contact authors directly

Introduction. During revision surgery, the active electrode of an electrocautery device may get close to the implant, potentially provoking a flashover. Incidents have been reported, where in situ retained hip stems failed after isolated cup revision. Different sizes of discoloured areas, probably induced by electrocautery contact, were found at the starting point of the fracture. The effect of the flashover on the implant material is yet not fully understood. The aim of this study was to investigate the fatigue strength reduction of Ti-6Al-4V titanium alloy after electrocautery contact. Material and Methods. 16 titanium rods (Ti-6Al-4V, extra low interstitial elements, according to DIN 17851, ⊘ 5 mm, 120 mm length) were stress-relief annealed (normal atmosphere, holding temperature 622 °C, holding time 2 h) and cooled in air. An implant specific surface roughness was achieved by chemical and electrolytic polishing (Ra = 0.307, Rz = 1.910). Dry (n = 6) and wet (n = 6, 5 µl phosphate buffered saline) flashovers were applied with a hand-held electrode of a high-frequency generator (Aesculap AG, GN 640, monopolar cut mode, output power 300 W, modelled patient resistance 500 Ω). The size of the generated discoloured area on the rod's surface - representative for the heat affected zone (HAZ) - was determined using laser microscopy (VK-150x, Keyence, Japan). Rods without flashover (n = 4) served as control. The fatigue strength of the rods was determined under dynamic (10 Hz, load ratio R = 0.1), force-controlled four-point bending (FGB Steinbach GmbH, Germany) with swelling load (numerical bending stress 852 MPa with a bending moment of 17.8 Nm) until failure of the rods. The applied bending stress was estimated using a finite-element-model of a hip stem during stumbling. Metallurgical cuts were made to analyse the microstructure. Results. The control rods failed at the pushers of the setup (median: 94,550, range: 194,000 cycles). The rods with flashover failed directly at the HAZ significantly earlier than the control rods (p = 0.018). The analysis of the microstructure showed a transformation of the equiaxed α+β microstructure to a bimodal state. The size of the HAZs were equal for the dry (median: 1.51 mm. 2. , range: 5.68 mm. 2. ) and wet flashovers (median: 0.92 mm. 2. , range: 2.50 mm. 2. , p = 0.792). The cycles to failure were smaller for the dry flashover (median: 22,650 cycles, range: 5,700) than the wet flashover but not reaching statistical significance (median: 32,200, range: 57,900; p = 0.052). No correlation between the dimension of the HAZs and the cycles to failure was found (dry: r. 2. = 0.019, p = 0.8; wet: r. 2. = 0.015, p = 0.721). Discussion. Flashovers induced by an electrocautery device reduce the fatigue strength of Ti-6Al-4V. Since no correlation between the size of the HAZs and the cycles to failure was found, every contact between electrocautery devices and metal implants should be avoided. For any figures or tables, please contact authors directly

Introduction. Impaction bone grafting (IBG) is a reliable technique for acetabular revision surgery with large segmental defects. However, bone graft resorption and cup migration are some of the limitations of this tecnique. We assess frequency and outcome of these complications in a large acetabular IBG series. Patients and Methods. We analysed 330 consecutive hips that received acetabular IBG and a cemented cup in revision surgery with large bone defects (Paprosky types 3A and 3B). Fresh-frozen femoral head allograft was morselized manually. The mean follow-up was 17 years (3–26). All data were prospectively collected. Kaplan-Meier survivorship analysis was performed. Changes in different paremeters regarding cup position were assessed pre- and postoperatively and at the follow- up controls. Only variations greater than 5º and 3 mm were considered. Results. The mean Harris Hip Score improved from 48.3+8.5 to 84.6+12.8 at final follow-up. The radiological analysis showed cup migration in 42 hips. The mean appearance time was 4.3 years (range, 1–25). Migration was progressive and painful in 27 hips (67.5%) requiring cup revision. Lateral mesh was more frequently associated with migrated cups (p=0.034). Cup tilt was found in 37 out 42 migrated cups, however cranial migration was more frequent in progressive migrated cups (p=0.02). There were 34 re-revisions, 27 due to aseptic cup loosening, 6 due to dislocation and one due to infection. The survival rate for any cause at 16 years was 81.2% (95% Confidence Interval (CI): 74.0 to 88.4) and for aseptic cup loosening was 83.4% (95% CI: 76.2–90.6). In all surviving hips trabecular incorporation was observed without radiolucent lines. Conclusions. IBG continues to be a reliable technique for large defects in acetabular revision surgery. Bone graft resorption and cup migration was not frequent in this large series and one-third of cases were not progressive. Cup migration was more frequent in cases with a segmental roof defect in which a lateral mesh was used

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

THA continues to improve but complications still occur. Improper restoration of hip mechanics can lead to a number of clinical problems: increase in leg length, soft tissue laxity, weakness of the abductors, mechanical impingement, increase of wear and improper implant sizing can lead to thigh pain, subsidence and hip dislocation. Six-hundred-and-fifty-five primary cementless THA were performed over the past twenty-four years by the senior author at two hospitals. Three different stems were used, two being modular and one being monoblock. A variety of cups head sizes and bearing material were used. All cups were implanted cementless. All surgeries were performed with the posterior approach. Sixty percent of patients were female forty percent males. Majority of cases were for OA. Cup revisions have been the biggest problem to-date with excessive wear of the poly material. This is more than likely due to the first and second generation designs that had poor locking mechanics. Over the last four years since going to MOM technology cup revisions have not been seen. On the femoral side there have been no femoral lysis, five dislocations two treated closed and three open reductions treated with constrained sockets. Four stem revisions, all for late sepsis. There has been two recent aseptic loosening, and only one traumatic dislocation since going to large MOM heads. One was one post-op with an ASR MOM cup that had spun out of position of function and the second a week later that was only six weeks post-op and came in for her first post-operative visit. Routine use of intra-operative x-rays has resulted in +80% decision on fine-tuning of implant sizing by either increasing stem size and or femoral offset. Intra- operative x-rays provide valuable assistance and allow full advantage of the features and benefits of stem modularity reducing post-operative complications

The authors entered patients into a randomised trial to compare the results of the use of cemented and cementless acetabular prostheses between 1993 and 1995. The results of mid-term wear studies at average follow up of eight years were reported in the journal in 2004. We now present long-term results to show the eventual fate of the hip replacements under study. The initial study group of 162 patients was randomly assigned to a modular titanium cup with a polyethylene liner or an all polyethylene cemented cup. All patients received a cemented stem with a 26 mm head and a standardised surgical technique. The polyethylene wear was estimated via head penetration measurement and the mid-term results showed a significantly higher wear rate in the cementless cups compared to the cemented cups (0.15mm/yr vs. 0.07mm/yr p<0.0001). The prediction was that this would lead to a higher rate of aseptic loosening in the cementless group. Patients have now been re-examined at an average of 15 years with the main emphasis on prosthesis survival. Wear studies were also performed. There were exclusions from the initial study because of death and reoperation for reasons other than aseptic loosening. The number of patients in this longer-term study had decreased as a result of death and loss to follow up. Revisions for aseptic loosening did not follow the path as suggested by the mid term wear studies. There were five cup revisions in the cemented group and one cup revision in the cementless group for aseptic loosening. No femoral stem was revised for aseptic loosening. Details of the long-term wear studies will be presented and osteolysis rates and extent documented. Despite the statistically significant difference in wear rates at the mid term, an incorrect prediction of eventual loosening rates was made. The authors believe that there are many factors other than wear rates involved in longevity of fixation. We also believe there are many weaknesses in long term prospective, randomised trials in joint replacement and question whether they are, in fact, level 1 evidence in the age of evidence based medicine

Introduction. Acetabular fractures management is controversial since, despite a good anatomical reduction, clinical outcome is not satisfactory very often and the probability of a total hip arthroplasty (THA) is high. Surgical treatment include long operating times, large approach, blood loss, neural and muscle damage, and a high risk of failure and secondary osteoarthritis related to bone necrosis, cartilage damage, and bone loss. We hypothesized that the acetabular fracture management affected the clinical and radiological outcome of THA after posttraumatic arthritis. Materials and Methods. We compared 49 patients (49 hips) initially treated conservatively followed some months later by THA in conjunction with acetabular reconstruction (group 1); and 29 patients (29 hips) who had undergone THA after a failed osteosynthesis (group 2). There were more associated fractures according to Letournel in group 2. The mean age was 59.3±15.8 years for group 1 and 52.9±15.2 years for group 2. The mean delay between fracture and THA was 75.4±5 months for group 1 and 59.4±5 for group 2. The mean follow-up was 11.7 in group 1 and 10.2 in group 2. Preoperative bone defect was similar. We used bone autograft in 13 hips (26.5%) in group 1 and four (13.6%) in group 2. We used acetabular reconstruction plates in 2 hips with a pelvic discontinuity in group 1. Complications, clinical outcome according to Harris Hip Score, and radiological reconstruction were compared. Two-way ANOVA with repeated measures were used for comparison. Results. There were 5 cups revised for aseptic loosening in group 1 and 2 in group 2. The cumulative probability of not having a cup revision at 16 years was 90.6% (95% confidence interval (CI) 78,1 to 100) for group 1 and 94.1% (95% CI 86.5 to 100) for group 2 (p=0.76). There were 4 sciatic palsies in group 2, 4 of which developed after trauma and 2 after osteosynthesis. There were no infections. Although pre-operative clinical score was better in group 1, post-operatively at latest follow-up there were no differences. The radiological reconstruction was better in group 1 for version angle (p=0.03) and abductor lever arm (p=0.02). The change from the pre- to post-operative situation was greater in group 2 for the latter (Delta value, p=0.002). The rate of post-operative heterotopic ossifications was greater in group 2 (p=0.04). Conclusions. Long-term clinical and radiograph results are good in patients who underwent THA after a complex acetabular fracture, however, primary THA in conjunction with acetabular reconstruction had a lower number of complications and a better radiographic acetabular reconstruction than a THA after failed osteosynthesis

In primary total hip replacements there are numerous options available for providing hip stability in difficult situations (i.e. Down's syndrome, Parkinson's disease). We have considered constrained liners in some of these cases. However, in the revision situation in general and in revision for recurrent dislocation situation specifically it is important to have all options available including tripolar constrained liners in order to optimise the potential for hip stability as well as function of the arthroplasty. Even with the newer options available dislocation rates of higher than 10–15% have been reported following revision surgery at institutions where high volumes of revision surgery are performed. Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups revision cases will always have more potential for dislocation. In these situations in the lower demand patient, constraint has provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate- term follow-up. Hence in these situations tripolar constrained liners remains the option we utilise. We are also confident in using this device in cases with instability or laxity where there is a secure well- positioned acetabular shell. We cement a dual mobility constrained liner in these situations using the technique described below. Present indication for tripolar constrained liners: low demand patient, large outer diameter cups, instability with well-fixed shells that are adequately positioned, abductor muscle deficiency or soft tissue laxity, multiple operations for instability. Technique of cementing liner into shell: score acetabular shell if no holes, score liner in spider web configuration, all one or two millimeters of cement mantle. Results. Constrained Dual Mobility Liner. For Dislocation: 56 Hips, 10 yr average f/u, 7% failure of device, 5% femoral loosening, 4% acetabular loosening. For Difficult Revisions:101 hips, 10 yr average f/u, 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips, 3.6 yr average f/u (2–10 years), 2 of 31 failures

Introduction. Iliopsoas impingement is a well described cause of groin pain after direct anterior total hip arthroplasty (THA). We proposed to evaluate the incidence, natural history and response to treatment of iliopsoas impingement after direct anterior total hip arthroplasty. Methods. A retrospective chart review of 725 consecutive patients who underwent anterior approach total hip arthroplasty between 2009 and 2014 was conducted. All surgeries were performed by one of two surgeons. Patients were included if they underwent primary anterior approach THA and had a minimum of 2 years of follow up. Patients who had a posterior approach, revision surgery or had less than 2 years of follow up were excluded. Iliopsoas impingement was identified if patients reported groin pain at greater than 6 weeks of postoperative follow up and in association with pain with resisted seated hip flexion. The natural history and response to treatment was recorded for patients identified as having iliopsoas impingement. Results. 900 patients met inclusion criteria. Of these, 120 (13.4%) developed groin pain following direct anterior total hip arthroplasty. The average time of onset was at 21 months postoperatively. At 2 years postoperatively, 16% of patients had symptoms, whereas 84% had resolution. 28% of patients responded to structured physical therapy, 22% improved with home stretching, 19% improved after arthroscopic psoas release, 9% after psoas sheath injection, and 6% required acetabular component revision. Conclusion. In our study population, iliopsoas impingement is not an uncommon finding after direct anterior total hip arthroplasty, but nearly half of these patients responded well to home stretching or physical therapy. In some cases, psoas injection and arthroscopic release was necessary. Rarely, cup revision was required for symptomatic relief

Revision of total hip arthroplasty (THA) is being performed with increasing frequency. However, outcomes of repeated revisions have been rarely reported in the literature, especially for severe defects. Cup revision can be a highly complex operation depending on the bone defect. In acetabular defects like Paprosky types 1 and 2 porous cementless cups fixed with screws give good results. Modern trabecular metal designs improve these good results. Allografts are useful for filling cavitary defects. In acetabular defects Paprosky types 3A and 3B, especially the use of trabecular metal cups, wedges, buttresses and cup-cage systems can produce good results. Difficult cases in combination with pelvic discontinuity require reconstruction of the acetabulum with acetabular plates or large cup-cages to solve these difficult problems. However, there is still no consensus regarding the best option for reconstructing hips with bone loss. Although the introduction of ultraporous metals has significantly increased the surgeon's ability to reconstruct severely compromised hips, there remain some that cannot be managed readily using cups, augments, or cages. In such situations custom acetabular components may be required. Individual implants represent yet another tool for the reconstructive surgeon. These devices can be helpful in situations of catastrophic bone loss. Ensuring long-term outcome, mechanical stability has a greater impact than restoring an ideal center of rotation. However, despite our consecutive case series there are no mid- to long-term results available so far. Re-revision for failed revision THA acetabular components is a technically very challenging condition

Revision of total hip arthroplasty (THA) is being performed with increasing frequency. However, outcomes of repeated revisions have been rarely reported in the literature, especially for severe defects. Cup revision can be a highly complex operation depending on the bone defect. In acetabular defects like Paprosky types 1 and 2 porous cementless cups maybe fixed with screws give good results. Modern trabecular metal designs improve these good results. Allografts are useful for filling cavitary defects. In acetabular defects Paprosky types 3A and 3B, impacted morselised allografts with a cemented cup technique produce good results. Difficult cases with pelvic discontinuity require reconstruction of the acetabulum with acetabular plates or large cup-cages to solve these difficult problems. However, there is still no consensus regarding the best option for reconstructing hips with bone loss. Although the introduction of ultraporous metals has significantly increased the surgeon's ability to reconstruct severely compromised hips, there remain some that cannot be managed readily using cups, augments, or cages. In such situations custom acetabular components may be required. Individual implants represent yet another tool for the reconstructive surgeon. These devices can be helpful in situations of catastrophic bone loss. Ensuring long-term outcome mechanical stability has a greater impact than restoring an ideal center of rotation. We have done so far 15 3D Printed Individual Implants. All of them where Paprosky Type 3B defects, 10 with a additional pelvis discontinuity. The mean follow-up is 18 months. All implanted devices are still in place, no infection, no loosening. However, despite our consecutive case series, there are no mid- to long-term results available so far. Re-revision for failed revision THA acetabular components is a technically very challenging condition. The 3D Printed Individual Implants have a lot of advantages, like excellent surgical planning and a very simple technique (operative time, blood loss, instruments). They are a very stable construct for extensive acetabular defects and pelvic discontinuity

In the revision situation in general and for recurrent dislocation specifically, it is important to have all options available including tripolar constrained liners in order to optimise the potential for hip stability as well as function. Even with the newer options available, dislocation rates of higher than 5% have been reported in the first two years following revision surgery at institutions where high volumes of revision surgery are performed (Wera et al). Because of the deficient abductors, other soft tissue laxity and the requirement for large diameter cups, revision cases will always have more potential for dislocation. In these situations, in the lower demand patient, tripolar constrained liners provided excellent success in terms of preventing dislocation and maintaining implant construct fixation to bone at intermediate term follow-up. Hence in these situations, tripolar with constraint remains the option we utilise in many cases. We are also confident in using this device in cases with instability or laxity where there is a secure well positioned acetabular shell. We cement a tripolar constrained liner in these situations using the technique described below. Present indication for tripolar constrained liners: low demand patient, abductor muscle deficiency or soft tissue laxity, large outer diameter cups, multiple operations for instability, instability with well-fixed shells that are adequately positioned. Technique of cementing liner into shell: score acetabular shell if no holes, score liner in spider web configuration, all one or two millimeters of cement mantle. Results: Constrained Tripolar Liner - For Dislocation: 56 Hips; 10 year average f/u; 7% failure of device, 5% femoral loosening, 4% acetabular loosening. Constrained Tripolar Liner - For Difficult Revisions: 101 hips; 10 year average f/u; 6% failure of device, 4% femoral loosening, 4% acetabular loosening. Cementing Liner into Shell: 31 hips; 3.6 year average f/u (2–10 years); 2 of 31 failures. We, like others, are trying to define cases where dual mobility will be as successful or more successful than tripolar constrained liners