Cemented total hip arthroplasty yields reliable results in short to medium term studies, but aseptic loosening remains a problem in long-term follow up, especially in young and active patients. Aseptic loosening has been related to wear, and in order to minimize wear various alternatives to the traditional metal on polyethylene have been proposed. Both ceramic on polyethylene (COP) and metal on metal (MOM) have been shown to produce less wear than metal on polyethylene (MOP). In order to study the effect of the bearing, we have utilized identical stems and cups while comparing the different bearings. Methods and material. 396 hips were randomized to MOP, COP or MOM using a cemented triple tapered polished stem (MS-30; Sulzer Orthopedics) with a cemented polyethylene cup (Weber; Sulzer, Orthopedics) and a 28 millimeter head. For the MOP and COP articulations, a all-polyethylene cup was used with a Protasul™ metal head or a Sulox™ alumina head, whereas a polyethylene cup with metal insert was used for the MOM articulations (Weber Polyethylene Cup with Metasul™ Insert) with a Metasul™ metal head. Harris Hip Score (HHS) and radiological evaluation was performed after two, five and seven years. Ethical approval was obtained. Results. HHS was available for 338 hips after seven years. The HHS in the MOP group (116 hips) was 93.7 (SD 9.0), 93.5 in the COP group (112 hips) (SD 8.8), and 91.0 (SD 13.4) in the MOM group (110 hips). Radiographic evaluation was available for 335 hips. Radiolucencies around the stem larger than one millimeter were found in five of 115 MOP hips, seven of 111 COP hips and in seven of 110 MOM hips. Periacetabular radiolucencies identified as larger than one millimeter were found in none of the 116 MOP hips, five of the 112 COP hips and in 19 of the 110 MOM hips. Ten revisions were performed. In the MOP group there were three revisions (infection, dislocation, pain); one in the COM group (infection), and six in the MOM group (three infections, two aseptic loosening and one septic loosening). Discussion. Clinically, the three bearing types perform equally well at seven years, and there are few signs of impending failure for the stem. However, there are an alarmingly high proportion of cups showing signs of loosening. Two hips have been revised in the MOM group for aseptic loosening as opposed to none in the two other groups, which adds to the concern. The MOM articulation used in this study should be monitored closely for signs of aseptic loosening

The Thompson hemiarthroplasty is a common treatment option for acute neck of femur fractures in the elderly population. Our department noted a significant number of patients returning with thigh pain, radiographic loosening and femoral osteolysis following cemented implantation of the titanium alloy version of the Thompson hemiarthroplasty. We are not aware of any previous reports documenting complications specific to the titanium Thompson implant and a retrospective cohort study was therefore initiated following clinical governance approval. 366 titanium alloy Thompson prostheses were implanted for hip fracture treatment between 2017 and 2020. As of February 2023, 6 of these have been revised at our hospital. 5 were revised for symptomatic femoral osteolysis and 1 presented with an acute periprosthetic fracture. All revised cases were determined to be aseptic. 32 living patients were excluded from recall on compassionate grounds due to permanent nursing home residence. 47 living patients were identified of which 33 attended for xray. 28 deceased and/or nursing home resident patients who had pelvis x-rays in the previous 12 months were also included in the analysis. Including the 6 index hips already revised, a total of 61 hip xrays were analysed, of which 19 hips (31.1%) showed radiographic evidence of femoral osteolysis or loosening. We conclude that there is a concerning incidence of femoral osteolysis and implant loosening associated with the titanium Thompson implant. We have discontinued use of the implant and reported our experience to the MHRA. We encourage other Scottish Health-Boards who use this implant to consider enhanced follow-up

Aims. Despite multiple trials and case series on hip hemiarthroplasty designs, guidance is still lacking on which implant to use. One particularly deficient area is long-term outcomes. We present over 1,000 consecutive cemented Thompson’s hemiarthroplasties over a ten-year period, recording all accessible patient and implant outcomes. Methods. Patient identifiers for a consecutive cohort treated between 1 January 2003 and 31 December 2011 were linked to radiographs, surgical notes, clinic letters, and mortality data from a national dataset. This allowed charting of their postoperative course, complications, readmissions, returns to theatre, revisions, and deaths. We also identified all postoperative attendances at the Emergency and Outpatient Departments, and recorded any subsequent skeletal injuries. Results. In total, 1,312 Thompson’s hemiarthroplasties were analyzed (mean age at surgery 82.8 years); 125 complications were recorded, necessitating 82 returns to theatre. These included 14 patients undergoing aspiration or manipulation under anaesthesia, 68 reoperations (5.2%) for debridement and implant retention (n = 12), haematoma evacuation (n = 2), open reduction for dislocation (n = 1), fixation of periprosthetic fracture (n = 5), and 48 revised stems (3.7%), for infection (n = 13), dislocation (n = 12), aseptic loosening (n = 9), persistent pain (n = 6), periprosthetic fracture (n = 4), acetabular erosion (n = 3), and metastatic bone disease (n = 1). Their status at ten years is summarized as follows: 1,180 (89.9%) dead without revision, 34 (2.6%) dead having had revision, 84 (6.6%) alive with the stem unrevised, and 14 (1.1%) alive having had revision. Cumulative implant survivorship was 90.3% at ten years; patient survivorship was 7.4%. Conclusion. The Thompson’s stem demonstrates very low rates of complications requiring reoperation and revision, up to ten years after the index procedure. Fewer than one in ten patients live for ten years after fracture. This study supports the use of a cemented Thompson’s implant as a cost-effective option for frail hip fracture patients. Cite this article: Bone Jt Open 2022;3(9):710–715

Aims. The aim of this study was to investigate the rate of revision for distal femoral arthroplasty (DFA) performed as a primary procedure for native knee fractures using data from the Australian Orthopaedic Association National Joint Arthroplasty Registry (AOANJRR). Methods. Data from the AOANJRR were obtained for DFA performed as primary procedures for native knee fractures from 1 September 1999 to 31 December 2020. Pathological fractures and revision for failed internal fixation were excluded. The five prostheses identified were the Global Modular Arthroplasty System, the Modular Arthroplasty System, the Modular Universal Tumour And Revision System, the Orthopaedic Salvage System, and the Segmental System. Patient demographic data (age, sex, and American Society of Anesthesiologists grade) were obtained, where available. Kaplan-Meier estimates of survival were used to determine the rate of revision, and the reasons for revision and mortality data were examined. Results. The AOANJRR identified 153 primary DFAs performed for native knee fractures in 151 patients during the study period, with 63.3% of these (n = 97) performed within the last five years. The median follow-up was 2.1 years (interquartile range 0.8 to 4.4). The patient population was 84.8% female (n = 128), with a mean age of 76.1 years (SD 11.9). The cumulative percent revision rate at three years was 10%. The most common reason for revision was loosening, followed by infection. Patient survival at one year was 87.5%, decreasing to 72.8% at three years postoperatively. Conclusion. The use of DFA to treat native knee fractures is increasing, with 63.3% of cases performed within the last five years. While long-term data are not available, the results of this study suggest that DFA may be a reasonable option for elderly patients with native knee fractures where fixation is not feasible, or for whom prolonged non-weightbearing may be detrimental. Cite this article: Bone Joint J 2022;104-B(7):894–901

The Olympia femoral stem is a stainless steel, anatomically shaped, polished and three-dimensionally tapered implant designed for use in cemented total hip arthroplasty (THA). The primary aim of this study was to determine the long-term survivorship, radiographic outcome, and patient reported outcome measures (PROMs) of the Olympia stem. Between May 2003 and December 2005, 239 patients (264 THAs) underwent a THA with an Olympia stem in our institution. PROMs were assessed using the Oxford Hip Score (OHS), EuroQol-5 dimensions (EQ-5D) score and patient satisfaction at mean 10-years following THA. Patient records and radiographs were then reviewed at a mean of 16.5 years (SD 0.7, 15.3 to 17.8) following THA to identify occurrence of complications or revision surgery for any cause. Mean patient age at surgery was 68.0 years (SD 10.9, 31–93 years). There were 156 women (65%, 176 THAs). Osteoarthritis was the indication for THA in 204 patients (85%). Stem survivorship at 10 years was 99.2% (95 % confidence interval [CI], 97.9%-100%) and at 15 years was 97.5% (94.6%–100%). The 15-year stem survival for aseptic loosening was 100%. Only one occurrence of peri-prosthetic fracture was identified, with no episodes of dislocation found. At a mean of 10 (SD 0.8, 8.7 –11.3) years follow-up, mean OHS was 39 (SD 10.3, range 7 – 48) and 94% of patients reported being very satisfied or satisfied. The Olympia stem demonstrated excellent 10-year PROMs, very high rates of stem survivorship and negligible peri-prosthetic fracture and dislocation rate at final follow-up beyond 15 years

Aims

Femoral periprosthetic fractures are rising in incidence. Their management is complex and carries a high associated mortality. Unlike native hip fractures, there are no guidelines advising on time to theatre in this group. We aim to determine whether delaying surgical intervention influences morbidity or mortality in femoral periprosthetic fractures.

Aims

To assess the feasibility of a randomized controlled trial (RCT) that compares three treatments for acetabular fractures in older patients: surgical fixation, surgical fixation and hip arthroplasty (fix-and-replace), and non-surgical treatment.

Aims

Periprosthetic fractures (PPFs) following hip arthroplasty are complex injuries. This study evaluates patient demographic characteristics, management, outcomes, and risk factors associated with PPF subtypes over a decade.

The purpose of this study was to describe the radiological characteristics of a previously unreported finding: posterior iliac offset at the sacroiliac joint and to assess its association with pelvic instability as measured by initial displacement and early implant loosening or failure. Radiographs from 42 consecutive patients with a mean age of 42 years (18 to 77; 38 men, four women) and mean follow-up of 38 months (3 to 96) with Anteroposterior Compression II injuries, were retrospectively reviewed. Standardised measurements were recorded for the extent of any diastasis of the pubic symphysis, widening of the sacroiliac joint, static vertical ramus offset and a novel measurement (posterior offset of the ilium at the sacroiliac joint identified on axial CT scan). Pelvic fractures with posterior iliac offset exhibited greater levels of initial displacement of the anterior pelvis (anterior sacroiliac widening, pubic symphysis diastasis and static vertical ramus offset, p < 0.001,0.034 and 0.028, respectively). Pelvic fractures with posterior ilium offset also demonstrated higher rates of implant loosening regardless of fixation method (p = 0.05). Posterior offset of the ilium was found to be a reliable and reproducible measurement with substantial inter-observer agreement (kappa = 0.70). Posterior offset of the ilium on axial CT scan is associated with greater levels of initial pelvic displacement and early implant loosening. Cite this article: Bone Joint J 2014;96-B:1535–9

Aims

Minimally invasive fixation of pelvic fragility fractures is recommended to reduce pain and allow early mobilization. The purpose of this study was to evaluate the outcome of two different stabilization techniques in bilateral fragility fractures of the sacrum (BFFS).

Aims. Will Hydroxyapatite hip (HA) arthroplasty associated with ceramic bearings produce uncomplicated function in younger, active patients’ The incidence of aseptic loosening, dislocation and broken implants has been particularly investigated. Debris disease from plastic debris contributes to aseptic loosening. Hard-Hard bearings should obviate this problem. Metal-metal will release ions which might be deleterious. Experience with metal-metal resurfacing has high lighted problems including pseudo-tumours. Ceramic bearings may fracture but otherwise appear free of complications. Methods. This is a study extending over 19 years of 626 HA hip arthroplasties with ceramic bearings. Annual review using Harris Hip Score to assess pain and function and X-rays to check osseointegration has been performed. Alumina ceramic was inserted in 467 hips. The newer Zirconia Toughened Alumina (ZTA) has been inserted in 169 hips. There are 118 hips still under review at 10 or more years. Results. Aseptic loosening is unusual (one stem, two acetabulae (3 of 1252 components, 0.24%) Failure from mal-orientation with repeated dislocation occurred in six hips (0.96%). Three alumina heads (0.48%) and two alumina liners (0.32%) broke. There has been no failure of ZTA ceramic. No patients have thigh pain. Osteolysis and debris disease have not arisen. Harris Hip Scores show 91.2% scoring over 90 or 100. Lower scores mostly relate to other joint and medical problems. Conclusions. Assessments confirm that patients remain well. Aseptic loosening of HA hips is rare at 0.24%. Failure from broken alumina components is unusual. Alumina has now been superseded by ZTA for implantation. Ceramic on ceramic is a reliable selection for bearing surfaces in patients of any age and either sex

Background. Both from experimental studies and the large arthroplasty registries there is evidence that bacteria are more often involved in implant loosening then is currently reported. To further elucidate this potential problem, the current study investigated the hypothesis that many total hip arthroplasty revisions, classified as aseptic, are in fact low-grade infections missed with routine diagnostics. Methods. In 7 Dutch hospitals, 176 patients with the preoperative diagnosis of aseptic loosening of their total hip arthroplasty were enrolled. From each patient, the preoperative history was obtained. During surgery, between 14 and 20 tissue samples were obtained for routine culture, pathology analysis and broad range 16S rRNA PCR with reverse line blot hybridization (PCR-RLB). Samples were taken from the (neo-) capsule and acetabular and femoral interface tissue. Cultures were performed locally according to similar protocols. One specialized pathologist, blinded for all other results, analyzed all pathology samples. The PCR-RLB analysis was performed centrally, using a technique previously validated for orthopedic use. Patients were classified as not infected, suspect for infection or infected, according to strict, predefined criteria. Each patient had a follow-up visit after 1 year. Results. Seven patients were classified as infected, of whom 4 were not identified by routine culture. In these patients, positive PCR-RLB results were supported by pathology analyses suspect for infection as well. An additional 15 patients were suspect for infection as well. The microorganisms identified were low virulent bacteria, like coagulase negative staphylococci and Proprionibacterium acnes, in most cases. Twenty of these 22 patients received a cemented prosthesis, fixated with antibiotic-loaded bone cement. All patients received prophylactic systemic antibiotics, after obtaining the tissue samples. Seven of the 22 patients reported complaints one year post-surgery, only one showing signs of early loosening. However, in none of the patients additional surgery was performed. Discussion. Although percentages were not as high as previously reported in literature, between 4 and 13 percent of patients with the preoperative diagnosis of aseptic loosening were infected. However, as thorough debridement was performed during surgery and prophylactic antibiotics were used, it did not have many clinical consequences, as most patients performed well at the 1-year follow-up. Whether it has implications for long-term implant survival remains to be seen

Introduction. The options for the treatment of the young active patient with unicompartmental symptomatic osteoarthritis and pre-existing Anterior Cruciate Ligament (ACL) deficiency are limited. Patients with ACL deficiency and end-stage medial compartment osteoarthritis are usually young and active. The Oxford Unicompartmental Knee Replacement (UKA) is a well established treatment option in the management of symptomatic end-stage medial compartmental osteoarthritis, but a functionally intact ACL is a pre-requisite for its satisfactory outcome. If absent, high failure rates have been reported, primarily due to tibial loosening. Previously, we have reported results on a consecutive series of 15 such patients in whom the ACL was reconstructed and patients underwent a staged or simultaneous UKA. The aim of the current study is to provide an update on the clinical and radiological outcomes of a large, consecutive cohort of patients with ACL reconstruction and UKA for the treatment of end-stage medial compartment osteoarthritis and to evaluate, particularly, the outcome of those patients under 50. Methods. This study presents a consecutive series of 52 patients with ACL reconstruction and Oxford UKA performed over the past 10 years (mean follow-up 3.4 years). The mean age was 51 years (range: 36–67). Procedures were either carried out as Simultaneous (n=34) or Staged (n=18). Changes in clinical outcomes were measured using the Oxford Knee Score (OKS), the change in OKS (OKS=Post-op − Pre-op) and the American Knee Society Score (AKSS). Fluoroscopy assisted radiographs were taken at each review to assess for evidence of loosening, radiolucency progression, (if present), and component subsidence. Results. Five year survival was 90%. At last follow-up, the mean outcome scores for the group were: OKS 40 (SD: 8.3), objective AKSS 77 (SD: 16.1), functional AKSS 93 (SD: 13.7) and OKS of 11. Complications were recorded in three patients, (one early infection requiring a two-stage revision, a bearing dislocation and progression of OA in the lateral compartment). 25 patients, whose procedure occurred under the age of 50, had mean outcome scores of: OKS 38 (SD: 7.7), objective AKSS 73 (SD: 20.2), functional AKSS 93 (SD: 11.9) and OKS 12. No patients had radiological evidence of component loosening. Discussion and Conclusion. This study has demonstrated that combined ACL reconstruction and Oxford UKA provide good medium-term clinical and radiological results. The mobile bearing used in the Oxford knee minimises wear and our radiographic study has seen no suggestions of loosening

In rheumatoid arthritis (RA), non constrained or semi-constrained prostheses can be used. The authors used the Kudo III, IV or V or iBP prostheses 54 times from 1994 to 2003. After initial satisfactory results, they had to change one or both implants for several reasons: humeral stem fracture (5 cases), unipolar humeral loosening (1 case), ulnar loosening without laxity (8 cases), polyethylene wear (11 cases), due to progressive ulnar collateral ligament lengthening and progressive valgus deformity, without or with metallosis, due to contact between Cr-Co humeral component and titanium alloy ulnar component, chronic infection (1 case). When the local conditions were satisfactory (bone stock, ligament balance), the fractured or loosened component was changed. When the conditions were bad (poor bone stock, ligament misbalance, metallosis), both implants were removed; posterior humeral and/or medial or lateral ulnar window were used to removed the uncemented stems still osteointegrated. All the bipolar operations used the Coonrad-Morrey prosthesis, but the last case a Discovery prosthesis. The operative tricks are described, the management of the extensor apparatus is discussed, the clinical outcomes (especially the extensor apparatus function, most often weak) and the radiographic outcomes are presented

The Low Contact Stress (LCS) mobile-bearing total knee replacement (TKR) was designed to minimize polyethylene wear, aseptic loosening and osteolysis. However, registry data suggests there is a significantly greater revision rate associated with the LCS TKR. The primary aim of this study was to assess long-term survivorship of the LCS implant. Secondary aims were to assess survival according to mechanism of failure and identify predictors of revision. We retrospectively identified 1091 LCS TKRs that were performed between 1993 and 2006. There was incomplete data available 33 who were excluded. The mean age of the cohort was 69 (SD 9.2) years and there were 577 TKRs performed in females and 481 in males. Mean follow up was 14 years (SD 4.3). There were 59 revisions during the study period: 14 for infection, 18 for instability, and 27 for polyethylene wear. 392 patients died during follow up. All cause survival at 10-year was 95% (95%CI 91.7–98.3) and at 15-year was 93% (95%CI 88.6–97.8). Survival at 10-years according to mechanism of failure was: infection 99% (95%CI 94–100%), instability 98% (95%CI 94–100%), and polyethylene wear 98% (95%CI92–100). Of the 27 with polyethylene wear only 19 had associated osteolysis requiring component revision, the other 8 had simple polyethylene exchanges. Cox regression analysis, adjusting for confounding variables, identified younger age was the only predictor of revision (hazard ratio 0.96, 95%CI 0.94–0.99, p=0.003). The LCS TKR demonstrates excellent long-term survivorship with a low rate of revision for osteolysis, however the risk is increased in younger patients

Introduction. Alternative bearings – metal-on-metal and ceramic-on-ceramic bearings have been introduced in the last decade with the aim to diminish wear and, subsequently, aseptic loosening and osteolysis. These bearings were aimed for younger, more active patients. Clinical results which would compare the performance of various alternative and traditional bearings are scarce. Methods. Between January 2000 and December 2002, we performed 487 total hip replacements in 474 patients using three types of bearings: metal-on-metal (MOM), metal-on-polyethylene (MOP), and ceramic-on-ceramic (COC). All patients received the same type of acetabular cup (Bicon-Plus, Plus Orthopedics) and same type of femoral component (SL-Plus, Plus Orthopedics). We used the hospital computer database for the evaluation of patient data and data on revision operations. Results. At a mean follow-up of 8.5 years (range, 6.8 to 9.9 years), eighteen hips were revised. Seventeen revisions were aseptic, and one was septic. The percentage of revision in the whole group was 3.7%. The percentage of revisions for individual groups of bearings varied and ranged from 1.5% in the MOP group, 4.1% in the COC group to 8.7% in the MOM group. Reasons for revisions were analyzed in details. We noticed that the percentage of aseptic loosening differed among the groups, with the MOM group having the highest percentage of revisions due to aseptic loosening. Conclusions. The results obtained for this large series of THRs with the same type of acetabular and femoral components, and differing only in the type of bearing, indicate that the combination of material of acetabular cup and femoral head affect the performance of the hip prosthesis

Aim. In the last years, many short hip stem variants were developed, almost always sharing the principle of metaphyseal and proximal diaphyseal anchorage. In this study, we analyzed the midterm results after implanting short cementless hip stem of ESKA. Methods. A total of 380 total hip replacements using the ESKA-short cementless stems were performed in a series of 340 patients between November 2002 till May 2008. The clinical and radiological evaluation of the patients was done in September 2008. The mean follow up was 37 months (3–54 months). Results. The mean age of the patients was 65 years (35–85 years). The indications varied between osteoarthritis (n=342), avascular necrosis (n=23) and aseptic loosening of stem (n=15). Good clinical and radiological outcome without complications was observed in 361 cases. However, complications were recorded in 19 cases. Aseptic loosening was noted in 4 cases and was treated with stem exchange. Deep infection occurred in 5 cases, 3 of which had direct exchange and 2 had two-stage delayed reconstruction. Dislocation was noted in 2 cases, which were revisions after aseptic loosening. 8 patients suffered intraoperative femur fissures, 7 of which healed completely after prolonged partial weight bearing postoperatively (n=4 without osteosynthesis, n=3 needed adjunctive cerclage around the proximal femur). Only 1 spiral fracture was recorded and needed a periprosthetic NCB-plate. Conclusion. Our own experience with cementless short hip stems is, in accordance with other studies, also encouraging. Based on the metaphyseal and proximal diaphyseal anchorage, short stems established themselves as a surgical option in the hip replacement surgery. There was no increase in the postoperative complication rate compared with standard total hip arthoplasty. It is also an option for elderly population. However, long-term outcome is still to be investigated

Background. Second-generation high-carbon CoCrMo-alloy metal-on-metal total hip arthroplasty (THA) was introduced in the late 1980s following reports of early loosening, impingement, pronounced wear, and hypersensitivity in the first-generation metal-on-metal articulations. There has been inconsistent data that specifically addresses the clinical performance and longevity of second-generation metal-on-metal THA. The purpose of this study was to evaluate the survival of second-generation metal-on-metal primary THA and to assess the influence of demographic factors on implant survival in a large patient cohort. Methods. One thousand two hundred and seventy second-generation 28 mm metal-on-metal primary THA in 1121 patients were performed at one institution from 1994 to 2004. According to the International Documentation and Evaluation System patients were followed routinely at one year, two years and every five years thereafter. Clinical and radiographic outcome data was prospectively recorded using a hospital joint registry. At a mean follow-up of 6.8 years postoperatively, the probability of survival of THA was estimated using the method of Kaplan and Meier. Relative risk factors for implant failure that included age, gender, BMI, type of implant fixation and size of implant components were calculated using the Cox proportional-hazards model. Results. Sixty three (5%) hips were revised because of aseptic loosening (28 hips), infection (8 hips), periprosthetic fracture (8 hips), recurrent dislocation (8 hips), pain without implant loosening (7 hips) and breakage of the cup (4 hips). The probability of survival at ten years, with revision for any reason as the endpoint, for the THA as a whole was 0.90 (95% confidence interval, 0.87 to 0.94). The probability of survival for the cup was 0.90 (95% confidence interval, 0.86 to 0.93) and for the stem 0.94 (95% confidence interval, 0.91 to 0.97). No demographic factors or covariates were found to significantly affect survivorship. Conclusion. Second-generation metal-on-metal primary THA did not demonstrate a superior probability of survival at ten years compared with previous reports on other weight-bearing surfaces. Based on these findings and with consideration of concerns that relate to putative local and systemic toxicity of metal debris, the use of second-generation metal-on-metal articulations for primary THA remains moot

Background. Wear particles are considered to be the major culprit for the aseptic loosening. Their characterization is thus crucial for the understanding of their bioreactivity and contribution to the development of aseptic loosening. Methods. Metal wear debris particles were analyzed directly in periprosthetic tissue resins by scanning electron microscopy (SEM) combined with back-scattered electron imaging (BSE) and energy dispersive X-ray spectroscopy (EDS). Four groups of tissue samples retrieved at revision operations of loosened hip implants with different bearing surfaces (metal-on-metal, ceramic-on-polyethylene and metal-on-polyethylene), and different material of the femoral stem (Ti alloy, CoCrMo and polymer combined with stainless steel) were investigated. Tissue samples were first analyzed histologicaly. Sections from the same paraffin blocks were then carbon coated and analyzed using SEM/BSE/EDS method. Results. Metal particles were detected in all samples. Their composition corresponded to the composition of the implant components. The gradation of metal particles ranged from +1 to +3. A considerable number of big metal particles were actually agglomerates of submicron particles visible only at higher magnification. The clustering of particles was observed primarily for CoCrMo and, to a lesser extent, for stainless steels particles. The median sizes of CoCrMo clusters in two groups of samples were 2.9 1.8 m (range, 0.5 to 7.6 m) and 3.2 1.0 m (range, 1.9 to 5.4 m). The effect of clustering was not observed for Ti particles. The median sizes of individual Ti particles determined in two groups of samples were 2.5 3.6 m (range, 0.4 to 17.3 m) and 4.3 2.8 m (range, 0.8 to 11.0 m). Conclusion. Scanning electron microscopy combined with back-scattered electron imaging is an appropriate and selective method to recognize metal particles in tissue sections, without being destructive to specimens. When the size of the particles is considered, however, it should be differed between the size of individual particles and size of clusters of particles. Besides its benefits, this study has some limitations: the detection of particles smaller than 0.4 m is difficult, and this method cannot be used to identify polyethylene particles

Understanding the cause of failure of total knee arthroplasties (TKA) is essential in guiding clinical decision making and adjusting treatment concepts for revision surgery. The purpose of the study was to determine current mechanisms of failure of TKA and to describe changes and trends in revision surgery over the last 10 years. A retrospective review was done on all patients who had revision total knee arthroplasty during a 10-year period (2000–2009) at one institution. The preoperative evaluation in conjunction with the intraoperative findings was used to determine causes of failure. All procedures were categorizes as Sharkey et al. described previously. The data was analyzed regarding the cause of failure and displaying the incidence and trends over the last 10 years. 1225 surgeries were done in the time period with a steady increase of procedures per year (34 procedures in 2000 to 196 in 2009). The most common cause of revision TKA was aseptic failure in 65% and septic failure in 31% of the reviewed cases. However, we could observe a steady proportional increase of the septic classified revisions over the time. Both categories could be subdivided to specific causes of failure including aseptic loosening (24%), anterior knee pain (20%), instability (6,4%), arthrofibrosis (4,9%), PE wear (3,6%), malpositioning/malrotation (2,7%) periprosthetic fracture (2,0%) and other (4,6%), or in early (12,9%), late (15,4%) or low-grade infection (3,3%), respectively. Complementary to the classification Sharkey et al. described in 2002 we identified new subcategories of failure: malrotation (since 2003), Low-Grade-Infection (since 2006), allergic failure/loosening (since 2006), Mid-Flexion-Instability (since 2007), soft tissue impingement (since 2009). The incidence of the classic aseptic loosening due to PE wear shows a clear decrease in the last 10 years whereas we could observe an increase of the new diagnosis of instability, malrotation or low-grade-infection as determined cause of failure. The detailed analysis of the failure mechanism in total knee arthroplasty is important to understand the clinical problem and to adjust treatment strategies. We were able to complement present classifications and give a first overview on the incidence for specific causes of failure. Our data shows changes in the indication for surgery over the time and compared to the collective of Sharkey et al. from 1997–2000. This might be due to new diagnostic methods and better implant materials as well as to a generally increased awareness of the specific mechanism of TKA failure