Pathological assessment of periprosthetic tissues is important, not only for diagnosis, but also for understanding the pathobiology of implant failure. The host response to wear particle deposition in periprosthetic tissues is characterised by cell and tissue injury, and a reparative and inflammatory response in which there is an innate and adaptive immune response to the material components of implant wear. Physical and chemical characteristics of implant wear influence the nature of the response in periprosthetic tissues and account for the development of particular complications that lead to implant failure, such as osteolysis which leads to aseptic loosening, and soft-tissue necrosis/inflammation, which can result in pseudotumour formation. The innate response involves phagocytosis of implant-derived wear particles by macrophages; this is determined by pattern recognition receptors and results in expression of cytokines, chemokines and growth factors promoting inflammation and osteoclastogenesis; phagocytosed particles can also be cytotoxic and cause cell and tissue necrosis. The adaptive immune response to wear debris is characterised by the presence of lymphoid cells and most likely occurs as a result of a cell-mediated hypersensitivity reaction to cell and tissue components altered by interaction with the material components of particulate wear, particularly metal ions released from cobalt-chrome wear particles. Cite this article: Professor N. A. Athanasou. The pathobiology and pathology of aseptic implant failure. Bone Joint Res 2016;5:162–168. DOI: 10.1302/2046-3758.55.BJR-2016-0086

Introduction. Mechanical or corrosive failure of total knee arthroplasties (TKAs) is difficult to diagnose with current laboratory and radiographic analyses. As such, the goal of this study was to determine the mean blood concentration of cobalt, chromium, and titanium in a series of revision TKAs with mechanical implant failure and evaluate whether they facilitated identification of the underlying TKA failure mechanism. Methods. Serum cobalt, chromium, and titanium levels and synovial fluid characteristics were evaluated in 12 patients (13 aseptic revision TKAs) who underwent revision TKA between 2000 and 2020 at a single academic institution for mechanical implant failure or corrosion. Seventy-five percent were re-revisions of previously revised TKAs. Mean time to revision was 6 years. Modular metallic junctions were present in 100%. Twenty-five percent did not have another in situ total joint arthroplasty, and the remaining patients did not have a metal-on-metal articulation that could lead to elevation in serum metal ion levels. Mean follow-up after the revision TKA was 8 months. Results. Mean serum cobalt, chromium, and titanium concentrations were 11 ng/mL, 6 ng/mL, and 3 ng/mL, respectively. Serum metal ion levels facilitated failure mechanism identification in 75%, which included modular junction failure (6 cases), constraint locking mechanism failure (3 cases), corrosion of modular metallic interfaces (2 cases), and implant fracture (1 case). Arthrocentesis was performed in 75%. Mean synovial fluid cell count was 950 cells/mcL. Monocytes were the predominant mean cell type (41%), followed by neutrophils (35%), and lymphocytes (22%). Conclusion. Serum metal ion assessment should be considered when the etiology of painful primary or revision TKAs, particularly those with modular metallic junctions, remains elusive after routine evaluation

To determine the outcome of subtrochanteric fractures treated by intramedullary (IM) nailing and identify causes for implant failure. We performed a retrospective analysis of all subtrochanteric fractures treated by intramedullary nailing in Belfast trauma units between February 2006 and 2009. This subgroup of patients was identified using the Fractures Outcome Research Database (FORD). Demographic data, implant type, operative details, duration of surgery and level of operator were collected and presented. Post-operative X-rays were assessed for accuracy of reduction. One hundred and twenty two (122) patients were identified as having a subtrochanteric fracture treated by IM nailing. There were 79 females and 43 males. Age range was 16 to 93 (mean 78). 95 (78%) cases were performed by training grades and 27 (22%) by consultants. Duration of surgery ranged from 73–129mins (mean 87mins). 47 patients (38.5%) were found to have a suboptimal reduction and 75 patients (61.5%) had an anatomical reduction on immediate post-operative x-ray. One year from surgery 73/122 patients were available for follow up. Of those patients with suboptimal reduction, 13/47 (27.7%) required further surgery. 8 required complete revision with bone grafting, and 5 underwent dynamisation. A further 6 patients had incomplete union. In the anatomical group, 4 patients underwent further surgery (5%). 3 required dynamisation and one had exchange nailing for an infected non-union. 3 patients had incomplete union at last follow up. 5/47 (10.6%) had open reduction in the suboptimal group compared to 25/75 (33.3%) in the anatomical group. Of the 27 cases performed by consultants, 13 (48%) were open reduction, compared to 17/93 (18%) by training grades. This study has shown that inadequate reduction of subtrochanteric fractures, leads to increased rates of non union and ultimately implant failure. We recommend a low threshold for performing open reduction to ensure anatomical reduction is achieved in all cases

Background. The management of non-unions of subtrochanteric femoral fractures with associated implant failure is challenging. This study assessed the outcome of a cohort of patients treated according to the diamond concept. Methods. Between 2005–2010 all patients with subtrochanteric aseptic non-unions presented post implant failure (Gamma Nail breakage) were eligible in the absence of severe systemic pathologies and comorbidities. Demographics, initial fracture pattern, method of stabilisation, mode of failure of metal work, time to revision of fixation, complications, time to union, and functional outcome were recorded over a minimum period of follow-up of 12 months. The revision strategy was based on the “diamond concept;” optimising the mechanical and biological environment (revision of fixation, osteoinduction/BMP-7, osteoconduction/RIA harvested graft, and osteogenicity/concentrate of bone marrow aspirate). Results. Out of 280 nailing procedures 12 (4.3%) cases met the inclusion criteria. A consistent mode of metalwork failure was recorded with initial breakage of the proximal distal locking screw followed by nail breakage at the lag screw level. Biomechanical SEM analysis of the nails revealed no structural damage besides the standard fatigue striation. Varus mal-reduction was present in all cases, with an average of 7.3 degrees (5–11). The average time to screw failure was 4.3 months (2–6) and nail failure was 5.9 months (4–10). All but one of the cases were revised to a 95 degrees blade plate and one to an Affixus nail. Time to union was 6.5 months (5–10). All but one of the cases by 12 months have returned to their preinjury level of mobilisation. Conclusion. Varus mal-reduction must be avoided in the initial stabilisation of subtrochanteric fractures. Proximal distal screw failure is predictive of future fracture non-union and subsequent nail breakage. The diamond concept for optimising mechanics and bone biology is a successful method for managing complex sub-trochanteric non-unions with failed metalwork

We examined the association between patient-related factors and the risk of initial, short- and long-term implant failure after primary total hip replacement. We used data from the Danish Hip Arthroplasty Registry between 1 January 1995 and 31 December 2002, which gave us a total of 36 984 patients. Separate analyses were carried out for three follow-up periods: 0 to 30 days, 31 days to six months (short term), and six months to 8.6 years after primary total hip replacement (long term). The outcome measure was defined as time to failure, which included re-operation with open surgery for any reason. Male gender and a high Charlson co-morbidity index score were strongly predictive for failure, irrespective of the period of follow-up. Age and diagnosis at primary total hip replacement were identified as time-dependent predictive factors of failure. During the first 30 days after primary total hip replacement, an age of 80 years or more and hip replacement undertaken as a sequela of trauma, for avascular necrosis or paediatric conditions, were associated with an increased risk of failure. However, during six months to 8.6 years after surgery, being less than 60 years old was associated with an increased risk of failure, whereas none of the diagnoses for primary total hip replacement appeared to be independent predictors

Aims. The aims of this study were to validate the outcome of total elbow arthroplasty (TEA) in patients with rheumatoid arthritis (RA), and to identify factors that affect the outcome. Methods. We searched PubMed, MEDLINE, Cochrane Reviews, and Embase from between January 2003 and March 2019. The primary aim was to determine the implant failure rate, the mode of failure, and risk factors predisposing to failure. A secondary aim was to identify the overall complication rate, associated risk factors, and clinical performance. A meta-regression analysis was completed to identify the association between each parameter with the outcome. Results. A total of 38 studies including 2,118 TEAs were included in the study. The mean follow-up was 80.9 months (8.2 to 156). The implant failure and complication rates were 16.1% (95% confidence interval (CI) 0.128 to 0.200) and 24.5% (95% CI 0.203 to 0.293), respectively. Aseptic loosening was the most common mode of failure (9.5%; 95% CI 0.071 to 0.124). The mean postoperative ranges of motion (ROMs) were: flexion 131.5° (124.2° to 138.8°), extension 29.3° (26.8° to 31.9°), pronation 74.0° (67.8° to 80.2°), and supination 72.5° (69.5° to 75.5°), and the mean postoperative Mayo Elbow Performance Score (MEPS) was 89.3 (95% CI 86.9 to 91.6). The meta-regression analysis identified that younger patients and implants with an unlinked design correlated with higher failure rates. Younger patients were associated with increased complications, while female patients and an unlinked prosthesis were associated with aseptic loosening. Conclusion. TEA continues to provide satisfactory results for patients with RA. However, it is associated with a substantially higher implant failure and complication rates compared with hip and knee arthroplasties. The patient’s age, sex, and whether cemented fixation and unlinked prosthesis were used can influence the outcome. Level of Evidence: Therapeutic Level IV. Cite this article: Bone Joint J 2020;102-B(8):967–980

Total hip replacement procedures provide a very effective treatment modality for a wide range of diseases and injures to joints. The annual number of primary and surgeries has been increasing. In Region Emilia Romagna, 4000000 inhabitants, 4587 total hip replacements (THA) were performed in 1997 and the number raised up to 5410 in 2002 ( + 18%). Emiarthoplasties were respectively 1914 and 2215 (+ 16%). Parallely number of revision raised from 550 to 938 (+71%). In 2003 incidence of primary THAs in Emilia-Romagna is 107/100.000 inhabitants, higher than mean national value (76/100000). Data of both primary and revision surgeries are collected by RIPO (Register for Orthopaedic Prosthetic Implantology) that started its activity in Rizzoli Institute on January 1990 and in Regione Emilia-Romagna on January 2000. The recording of data is done for each joint replacement operation and it consists on the identification of the patient, information about diagnosis or reason for re-operation, surgical approach, antibiotic and antithromboembolic prophylaxis, perioperative complications. Acetabular, femoral and head components are separately registered, on the basis of stickers with catalogue numbers provided by manufacturers with the implants. Fixation of the components is recorded as well. Among the purposes of the Register there are the identification of early prosthesis failures, the information of surgeons on the outcome of their patients, the creation of a benchmarking tool for consultants and the speedy identification of relevant patients if a particular prosthesis or a particular batch gives cause for concern. As for Scandinavian registers, revision is used as an end-point in the analyses. On this basis it is possible to calculate survival curves either aggregated or stratified. By Cox multivariate analysis it has been ascertained that risk factors in total hip arthroplasties are represented by sex (females have lower risk than males), by age (younger than 40 are more at risk than 40–70s, and older than 70 are less at risk than 40–70s) and by pathology (fracture, coxites and Paget diseases have higher risk than coxarthrosis). Basing on these data, survival analysis was normalized and the influence of articular coupling and fixation of the components on prosthesis outcome have been evaluated. It resulted that failures are more likely to occur when metal on metal, or metal on polyethylene or ceramic on polyethylene devices rather than ceramic on ceramic implants are implanted. Similarly cemented and hybrid THAs fail at higher rate than uncemented ones. All data are referred to a 11 years follow-up. At present time Kaplan Meier analysis indicates a survival rate of total hip arthroplasties performed at Istituto Rizzoli of nearly 90% at ten years follow-up (9717 primary implants, 435 failures). Main reasons for revisions are aseptic loosening of the cup (33%),aseptic loosening of both components (18%), aseptic loosening of the stem (17%), deep infection (7.9%),dislocation (7.6%),prosthesis fracture (3%) etc. Aseptic loosening represent, therefore, the most frequent cause for revision. Results obtained at Istituto Rizzoli fit in the benchmarking set by the British NICE (National Institute for Clinical Excellence) that states that the revision rate should be of 10% or less at 10 years. To improve these results attention should be pointed on new models: hip prosthesis technology is continually changing, with new designs and techniques being introduced. There is a need to strike a balance between using prostheses with published long-term performance data, and the need to develop and improve hip prosthesis. A solution to this problem could be to entrust reference clinical centers the evaluation of the effectiveness of any new prosthesis for at least three years, before opening free distribution in standard orthopaedic units,as suggested by NICE. Only models that reach the ‘entry benchmark’ in adequately sized, well conducted observational studies, can be implanted with a good safety. At present time it is unlikely that clinical evaluation data on long term effectiveness is required by Notified Body for ‘CE’ marking, unless new materials are involved in the manufacture. This happens despite the fact that even small changes to existing prostheses can have a significant impact on implant performance and revision rate. Other factors than the already discussed can influence the surgery outcome, and among these the volume of operations performed in the hospital, the ability of the surgeon and its confidence with the technique, the compliance of the patient. Only an overall view of the situation will allow to reach the goal of reduction of need for revision of total hip arthroplasties

We studied 12 patients (13 elbows) who underwent total elbow replacement (TER) using the Kudo Mk IV or V prosthesis between 1989 and 1997. There were eight females and four males (mean age: 61 years, range: 38–74 years). The diagnosis was Rheumatoid arthritis in 10 patients and osteoarthritis in two patients. In each patient the initial result was classified as either excellent or good. All these patients then reported the recurrence of severe pain at a mean of four years from the time of the primary operation. Radiographic examination demonstrated fracture of the humeral stem in 10 elbows and subluxation of the joint in three elbows. The fractured humeral components were exchanged for long stem components. The three subluxated elbows were found to have undergone delamination and loosening of the ulnar components which were revised. One of these required revision to a linked prosthesis due to bone loss. In each case metallosis was found involving principally the synovial tissues which were as far as possible excised. Each patient regained a similar range of movement to that following the primary arthroplasty but continues to experience episodes of pain requiring anti-inflammatory medication. This is in contrast to our patients requiring revision procedures for implant loosening or instability who have become pain free. We conclude that the development of metallosis complicating mechanical implant failure predisposes to persisting symptoms following revision arthroplasty and recommend that this should be undertaken sooner rather than later when mechanical failure is detected

Aims. We evaluated a large database with mechanical failure of a single uncemented modular femoral component, used in revision hip arthroplasty, as the end point and compared them to a control group treated with the same implant. Patient- and implant-specific risk factors for implant failure were analyzed. . Methods. All cases of a fractured uncemented modular revision femoral component from one manufacturer until April 2017 were identified and the total number of implants sold until April 2017 was used to calculate the fracture rate. The manufacturer provided data on patient demographics, time to failure, and implant details for all notified fractured devices. Patient- and implant-specific risk factors were evaluated using a logistic regression model with multiple imputations and compared to data from a previously published reference group, where no fractures had been observed. The results of a retrieval analysis of the fractured implants, performed by the manufacturer, were available for evaluation. Results. There were 113 recorded cases with fracture at the modular junction, resulting in a calculated fracture rate of 0.30% (113/37,600). The fracture rate of the implant without signs of improper use was 0.11% (41/37,600). In 79% (89/113) of cases with a failed implant, either a lateralized (high offset) neck segment, an extralong head, or the combination of both were used. Logistic regression analysis revealed male sex, high body mass index (BMI), straight component design, and small neck segments were significant risk factors for failure. Investigation of the implants (76/113) showed at least one sign of improper use in 72 cases. Conclusion. Implant failure at the modular junction is associated with patient- and implant-specific risk factors as well as technical errors during implantation. Whenever possible, the use of short and lateralized neck segments should be avoided with this revision system. Implantation instructions and contraindications need to be adhered to and respected. Cite this article: Bone Joint J 2020;102-B(5):573–579

Aim: The aim of our retrospective study was to evaluate the precision of implantation of two different resurfacing systems and if incorrect positioning is a risk factor for implant failure. Method:. We started with the Birmingham Hip Resurfacing system (MMT,UK) and later introduced the Durom resurfacing system (Zimmer). We analysed the follow-up rx of all patients operated in our clinic. We measured the inclination of the cup, the CCD-angle of the head component, the alignement in respect to the neck axis, if the component had an eccentric position or if superior or inferior notching had occured. We compared the rate of failure of the two systems. Patients: In 90 patients a Mc Minn hip resurfacing system was implanted. The mean age in this group was 52 years (range 29 – 68 years). There were 64 male and 26 female patients. In 75 patients we implanted a Durom resurfacing system. The mean age in this group was 53 years (range 20 – 72 years). There were 55 male and 20 female patients. Results: In both groups the mean CCD angle was higher than before surgery, indicating that the head component was usually implanted in a slight valgus position. In 20 % of the cases component alignement was not ideal in both systems. There were four revisions of patients with the Durom system and three revision of patients with the McMinn system. The main reason for failure was weakening of the superior neck portion. Conclusion: As we were in the learning curve in hip resurfacing in a high number of cases positioning of the implant was not as it should be. This remained in most cases without clinical consequences but weakening of the superior neck portion seems to be the main reason leading to failure

Despite great progress in implant design, materials and new implantation techniques aseptic loosening is still the most frequent cause of implant failure in THA, which was found to be increased especially in patients with osteonecrosis of the femoral head (ON-FH). While a direct link between aseptic loosening and periprosthetic bone loss still remains elusive, there is plentiful evidence for a close association with early migration of implant components. Although the beneficial effect of bisphonates on periprosthetic bone mass is well established, little is known to date about their effects on implant migration. This is an important issue, because successful prevention of early implant migration would provide strong evidence of a beneficial effect on the survival rate of THA. Previously, Krismer et al. found that a total migration of the cup of ≥ 1mm and a subsidence of ≥ 1.5mm 2 years after surgery was highly predictive for aseptic implant failure of THA within 8 to 10 years. Fifty patients with end-stage ON-FH were consecutively enrolled to receive either 4mg of ZOL or saline solution (CTR) in a double-blind fashion. Radiographs standardized for EBRA-digital analysis were performed at each follow-up exam at 7 weeks, 6 months, 1 year, and yearly thereafter. The minimum follow-up period was 2 years (median follow-up: 2.8 years). Migration of the acetabular and femoral components was analyzed with the EBRA-digital software (University of Inns-bruck, Austria) independently by 3 investigators fully blinded to randomization. Within the placebo group, distal migration of the stem (subsidence) steadily increased up to −1.2mm ± 0.6 SD at 2 years after THA without reaching a plateau phase (P< 0.001, Friedman ANOVA). Less but a nearly curvilinear migration pattern was found for the acetabular components, with a transverse migration of 0.6mm ± 1.0 SD and a vertical migration of 0.6mm ± 0.8 SD at 2 years (P< 0.001, Friedman ANOVA). Treatment with ZOL effectively minimized the migration of cups in both the transverse and vertical direction (0.15 mm ± 0.6 SD and 0.06 mm ± 0.6 SD, respectively, P< 0.05, ANOVA), and a trend to a decreased subsidence was also found for stem migration (−0.91 mm ± 0.51 SD; P=0.11, ANOVA). In addition, total cup migration exceeding 1mm at 2 years was significantly reduced by ZOL in 8 patients (12 vs 4 in CTR vs ZOL, respectively) as was also found in 6 patients for subsidence (≥ 1.5mm in 9 vs 3 patients in CTR vs ZOL, respectively) (P< 0.05, Fisher’s exact). This is the first clinical trial reporting that a single infusion of ZOL suffices to improve initial implant fixation in THA. Based on best evidence available to date, this new concept shows great promise of improving the long-term outcome in THA and should be given attention in long-term trial

355 non-cemented MOM arthroplasties, of a single surgeon, with a follow up of 3–16 years (avg. 7.5 years) were retrospectively reviewed for evidence of pseudotumor and aseptic mechanical failure. There were 186 with 28 mm heads, 126 with 34 mm heads, 47 with 38 mm heads, from a single manufacturer.

There were 5 revisions of 38 mm heads for atraumatic painful “metalosis” 4–8 years after implantation (10.7%).

There were 4 revisions of 34 mm heads for post-traumatic instability (dislocation) with secondary metalosis 4–7 years after implantation (3.1%)

There were 2 revisions of 28 mm heads for post-traumatic instability (dislocation) with secondary metalosis 6–12 years after implantation (1.1%).

There were 5 patients, all with 38 mm heads, with asymptomatic “psoas bursae” with elevated serum CR and Co levels (1.0–3.0).

All of the failed THR's had acetabular components with lateral tilt <50 degrees (35–50), and anteversion angles <15 degrees (0–15). 2 of the 34 mm and both 28 mm instabilities were the consequence of injuries sustained in motor vehicle accidents. The remaining 2 instabilities with 34 mm implants were the result of mechanical falls.

Particulate debris, whether secondary to polyethylene, ceramic or metal articulations has been well documented as a cause of synovitis and damage to bony and soft tissues adjacent to a THR. This debris appears to be the result of material wear and mechanical failure with use over time. Unlike native articular cartilage, these materials are incapable of self-lubrication. Therefore THR articulations are dependent upon the penetration of ambient synovial fluid to provide lubrication of the replacement surfaces. This study suggests that increase in head diameter may reduce penetration of synovial fluid between the articulating surfaces of a THR, compromising the lubrication of bearing surfaces; thereby contributing to accelerated wear and premature failure of larger MOM arthroplasties.

Tissues from five patients who underwent revision operations for failed total hip replacements were found to contain large quantities of particulate titanium. In four cases this metal must have come from titanium alloy screws used to fix the acetabular component; in the fifth case it may also have originated from a titanium alloy femoral head. Monoclonal antibody labelling showed abundant macrophages and T-lymphocytes, in the absence of B-lymphocytes, suggesting sensitisation to titanium. Skin patch testing with dilute solutions of titanium salts gave negative results in all five patients. However, two of them had a positive skin test to a titanium-containing ointment.

The aim of this study was to establish any association between implant cut-out and a Tip Apex Distance (TAD), ≥25mm, in proximal femoral fractures, following closed reduction and stabilisation, with either a Dynamic Hip Screw (DHS) or Intramedullary Hip Screw (IMHS) device. Furthermore, we investigated whether any difference in cut-out rate was related to fracture configuration or implant type.

WE conducted a retrospective review of the full clinical records and radiographs of 65 consecutive patients, who underwent either DHS or IMHS fixation of proximal femoral fractures. The TAD was measured in the standard fashion using the combined measured AP and lateral radiograph distances. Fractures were classified according to the Muller AO classification.

35 patients underwent DHS fixation and 30 patients had IMHS fixation. 5 in each group had a TAD≥25mm. There were no cut-outs in the DHS group and 3 in the IMHS group. 2 of the cut-outs had a TAD≥25mm. The 3 cut-outs in the IMHS group had a fracture classification of 31-A2, 31-A3 and 32-A3.1 respectively. In addition, the fractures were inadequately reduced and fixed into a varus position.

A TAD<25mm would appear to be associated with a lower rate of cut-out. The cut-out rate in the IMHS group was higher than the DHS group. Contributing factors may have included an unstable fracture configuration and inadequate closed fracture reduction at the time of surgery.

Objectives

Taper junctions between modular hip arthroplasty femoral heads and stems fail by wear or corrosion which can be caused by relative motion at their interface. Increasing the assembly force can reduce relative motion and corrosion but may also damage surrounding tissues. The purpose of this study was to determine the effects of increasing the impaction energy and the stiffness of the impactor tool on the stability of the taper junction and on the forces transmitted through the patient’s surrounding tissues.

The popularity of cementless total hip replacement (THR) has surpassed cemented THR in England and Wales. This retrospective cohort study records survival time to revision following primary cementless THR with the most common combination (accounting for almost a third of all cementless THRs), and explores risk factors independently associated with failure, using data from the National Joint Registry for England and Wales. Patients with osteoarthritis who had a DePuy Corail/Pinnacle THR implanted between the establishment of the registry in 2003 and 31 December 2010 were included within analyses. There were 35 386 procedures. Cox proportional hazard models were used to analyse the extent to which the risk of revision was related to patient, surgeon and implant covariates. The overall rate of revision at five years was 2.4% (99% confidence interval 2.02 to 2.79). In the final adjusted model, we found that the risk of revision was significantly higher in patients receiving metal-on-metal (MoM: hazard ratio (HR) 1.93, p < 0.001) and ceramic-on-ceramic bearings (CoC: HR 1.55, p = 0.003) compared with the best performing bearing (metal-on-polyethylene). The risk of revision was also greater for smaller femoral stems (sizes 8 to 10: HR 1.82, p < 0.001) compared with mid-range sizes. In a secondary analysis of only patients where body mass index (BMI) data were available (n = 17 166), BMI ≥ 30 kg/m² significantly increased the risk of revision (HR 1.55, p = 0.002). The influence of the bearing on the risk of revision remained significant (MoM: HR 2.19, p < 0.001; CoC: HR 2.09, p = 0.001). The risk of revision was independent of age, gender, head size and offset, shell, liner and stem type, and surgeon characteristics.

We found significant differences in failure between bearing surfaces and femoral stem size after adjustment for a range of covariates in a large cohort of single-brand cementless THRs. In this study of procedures performed since 2003, hard bearings had significantly higher rates of revision, but we found no evidence that head size had an effect. Patient characteristics, such as BMI and American Society of Anesthesiologists grade, also influence the survival of cementless components.

Cite this article: Bone Joint J 2013;95-B:747–57.

We report the outcome of 39 patients who underwent a modified Pauwels’ intertrochanteric osteotomy for nonunion of a femoral neck fracture following failed osteosynthesis. There were 31 men and eight women with a mean age of 47.2 years (34 to 59). By Pauwels’ classification, there were 11 Type II fractures and 28 Type III fractures. The mean follow-up was 7.9 years (2 to 19). In the 11 patients whose initial treatment had been osteotomy, union was achieved in nine (81.8%). In 28 patients whose initial treatment had been with a lag screw or a dynamic hip screw, union was achieved in 27 (96.4%). Limb lengths were equalised in 14 of 16 patients (87.5%) with pre-operative shortening. The mean neck-shaft angle improved significantly from 100.5° (80° to 120°) to 131.6° (120° to 155°) (p = 0.004). The mean modified Harris hip score was 85.6 points (70 to 97) and the mean modified Merle d’Aubigné score was 14.3 (11 to 18). Good to excellent functional outcomes were achieved in 32 patients (88.8%). A modified Pauwels’ intertrochanteric osteotomy is a reliable method of treating ununited fractures of the femoral neck following failed osteosynthesis: coxa vara and shortening can also simultaneously be addressed.

Cite this article: Bone Joint J 2014;96-B:1198–1201.

Aims. Safety concerns surrounding osseointegration are a significant barrier to replacing socket prosthesis as the standard of care following limb amputation. While implanted osseointegrated prostheses traditionally occur in two stages, a one-stage approach has emerged. Currently, there is no existing comparison of the outcomes of these different approaches. To address safety concerns, this study sought to determine whether a one-stage osseointegration procedure is associated with fewer adverse events than the two-staged approach. Methods. A comprehensive electronic search and quantitative data analysis from eligible studies were performed. Inclusion criteria were adults with a limb amputation managed with a one- or two-stage osseointegration procedure with follow-up reporting of complications. Results. A total of 19 studies were included: four one-stage, 14 two-stage, and one article with both one- and two-stage groups. Superficial infection was the most common complication (one-stage: 38% vs two-stage: 52%). There was a notable difference in the incidence of osteomyelitis (one-stage: nil vs two-stage: 10%) and implant failure (one-stage: 1% vs two-stage: 9%). Fracture incidence was equivocal (one-stage: 13% vs two-stage: 12%), and comparison of soft-tissue, stoma, and mechanical related complications was not possible. Conclusion. This review suggests that the one-stage approach is favourable compared to the two-stage, because the incidence of complications was slightly lower in the one-stage cohort, with a pertinent difference in the incidence of osteomyelitis and implant failure. Cite this article: Bone Jt Open 2023;4(7):539–550

Aims. Implant failure has become more common as the number of primary total ankle arthroplasties (TAAs) performed has increased. Although revision arthroplasty has gained attention for functional preservation, the long-term results remain unclear. This study aimed to assess the long-term outcomes of revision TAA using a mobile-bearing prosthesis in a considerably large cohort; the risk factors for failure were also determined. Methods. This single-centre retrospective cohort study included 116 patients (117 ankles) who underwent revision TAA for failed primary TAA between July 2000 and March 2010. Survival analysis and risk factor assessment were performed, and clinical performance and patient satisfaction were evaluated preoperatively and at last follow-up. Results. The mean duration from initial revision TAA to last follow-up was 15.0 years (SD 3.0; 11.2 to 20.5). The cumulative survival rates of the revised ankles were 81% (95% confidence interval (CI) 74% to 88%), 74% (65% to 82%), and 70% (61% to 79%) at five, ten, and 15 years, respectively. Comorbidities prior to primary TAA, aseptic loosening, instability, or grafting of cysts were found to be the most common risk factors for secondary revision. The median value for preoperative pain, as assessed using the visual analogue scale, declined from 6 (interquartile range (IQR) 5 to 8) to 2 (IQR 0 to 5) (p < 0.001) and the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 43 (SD 17) preoperatively to 70 (SD 20) (p < 0.001) at last follow-up. Conclusion. Revision TAA offers acceptable survival rates after 15 years; it therefore offers a valuable option for treatment of implant failure in carefully selected cases. Although patient-reported outcomes improve substantially, the degree of improvement reported following primary TAA is not achieved. Cite this article: Bone Joint J 2024;106-B(1):46–52

Aims. Proximal femoral endoprosthetic replacements (PFEPRs) are the most common reconstruction option for osseous defects following primary and metastatic tumour resection. This study aimed to compare the rate of implant failure between PFEPRs with monopolar and bipolar hemiarthroplasties and acetabular arthroplasties, and determine the optimum articulation for revision PFEPRs. Methods. This is a retrospective review of 233 patients who underwent PFEPR. The mean age was 54.7 years (SD 18.2), and 99 (42.5%) were male. There were 90 patients with primary bone tumours (38.6%), 122 with metastatic bone disease (52.4%), and 21 with haematological malignancy (9.0%). A total of 128 patients had monopolar (54.9%), 74 had bipolar hemiarthroplasty heads (31.8%), and 31 underwent acetabular arthroplasty (13.3%). Results. At a mean 74.4 months follow-up, the overall revision rate was 15.0%. Primary malignancy (p < 0.001) and age < 50 years (p < 0.001) were risk factors for revision. The risks of death and implant failure were similar in patients with primary disease (p = 0.872), but the risk of death was significantly greater for patients who had metastatic bone disease (p < 0.001). Acetabular-related implant failures comprised 74.3% of revisions; however, no difference between hemiarthroplasty or arthroplasty groups (p = 0.209), or between monopolar or bipolar hemiarthroplasties (p = 0.307), was observed. There was greater radiological wear in patients with longer follow-up and primary bone malignancy. Re-revision rates following a revision PFEPR was 34.3%, with dual-mobility bearings having the lowest rate of instability and re-revision (15.4%). Conclusion. Hemiarthroplasty and arthroplasty PFEPRs carry the same risk of revision in the medium term, and is primarily due to acetabular complications. There is no difference in revision rates or erosion between monopolar and bipolar hemiarthroplasties. The main causes of failure were acetabular wear in the hemiarthroplasty group and instability in the arthroplasty group. These risks should be balanced and patient prognosis considered when contemplating the bearing choice. Dual-mobility, constrained bearings, or large diameter heads (> 32 mm) are recommended in all revision PFEPRs. Cite this article: Bone Joint J 2021;103-B(10):1633–1640