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Background: The mode of femoral fixation for primary total hip arthroplasty (THA) is undetermined, with reported outcomes favoring different fixation methods. This study aimed to compare postoperative complications between cemented and cementless fixation at 90 days, 1 year, and 2 years in patients aged 65 years of age and older undergoing THA for osteoarthritis., Methods: Using an all-payer, national database, patients 65 years and older undergoing primary THA, either with cementless (n = 56,701) or cemented (n = 6,283) femoral fixation for osteoarthritis were identified. A 1:1 propensity-matched analysis for age, sex, comorbidity index, alcohol abuse, tobacco use, obesity, and diabetes was performed, resulting in n = 6,283 patients in each cohort. Postoperative outcomes, including postoperative periprosthetic joint infection, aseptic revision, surgical site infection, pulmonary embolism, venous thromboembolism, wound complications, dislocation, periprosthetic fracture, and aseptic loosening were assessed., Results: The cemented cohort had higher rates of infection (4.5 versus 0.8%, odds ratio [OR] 5.9, 95% confidence interval [CI] 4.33 to 7.93, P < .001), aseptic revision (2.9 versus 2.0%, OR 1.47, 95% CI 1.17 to 1.85, P = .001), venous thromboembolism (1.8 versus 1.3%, OR 1.40, 95% CI 1.05 to 1.87, P < .001), and aseptic loosening (1.5 versus 0.7%, OR 2.31, 95% CI 1.60 to 3.32, P < .001) at 90-days. At 1 and 2 years, the cemented cohort had higher rates of infection, aseptic revision, and aseptic loosening (all P < .001). Rates of periprosthetic fracture were similar at all time points (all P < .001)., Conclusions: Cemented fixation had higher rates of infection, aseptic loosening, and aseptic revision. This finding supports the current use of cementless fixation, but the ultimate decision regarding fixation type should be based on the proper optimization of the patient's comorbidities and bone quality., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Aims: Total hip arthroplasty (THA) is a very successful and cost-effective operation, yet debate continues about the optimum fixation philosophy in different age groups. The concept of the 'cementless paradox' and the UK 'Getting it Right First Time' initiative encourage increased use of cemented fixation due to purported lower revision rates, especially in elderly patients, and decreased cost., Methods: In a high-volume, tertiary referral centre, we identified 10,112 THAs from a prospectively collected database, including 1,699 cemented THAs, 5,782 hybrid THAs, and 2,631 cementless THAs. The endpoint was revision for any reason. Secondary analysis included examination of implant survivorship in patients aged over 70 years, over 75 years, and over 80 years at primary THA., Results: Cemented fixation had the lowest implant survival in all age groups, with a total ten-year survivorship of 97.0% (95% confidence interval (CI) 95.8 to 97.8) in the cemented group, 97.6% (95% CI 96.9 to 98.1) in the hybrid group, and 97.9% (95% CI 96.9 to 98.6) in the cementless group. This was not statistically significant (p = 0.092). There was no age group where cemented fixation outperformed hybrid or cementless fixation., Conclusion: While all fixation techniques performed well at long-term follow-up, cemented fixation was associated with the lowest implant survival in all age groups, including in more elderly patients. We recommend that surgeons should carefully monitor their own outcomes and use fixation techniques that they are familiar with, and deliver the best outcomes in their own hands. Cite this article: Bone Joint J  2022;104-B(2):206-211.

Aims: The aim of this study was to determine if uncemented acetabular polyethylene (PE) liner geometry, and lip size, influenced the risk of revision for instability or loosening., Methods: A total of 202,511 primary total hip arthroplasties (THAs) with uncemented acetabular components were identified from the National Joint Registry (NJR) dataset between 2003 and 2017. The effect of liner geometry on the risk of revision for instability or loosening was investigated using competing risk regression analyses adjusting for age, sex, American Society of Anesthesiologists grade, indication, side, institution type, surgeon grade, surgical approach, head size, and polyethylene crosslinking. Stratified analyses by surgical approach were performed, including pairwise comparisons of liner geometries., Results: The distribution of liner geometries were neutral (39.4%; 79,822), 10° (34.5%; 69,894), 15° (21.6%; 43,722), offset reorientating (2.8%; 5705), offset neutral (0.9%; 1,767), and 20° (0.8%; 1,601). There were 690 (0.34%) revisions for instability. Compared to neutral liners, the adjusted subhazard ratios of revision for instability were: 10°, 0.64 (p < 0.001); 15°, 0.48 (p < 0.001); and offset reorientating, 1.6 (p = 0.010). No association was found with other geometries. 10° and 15° liners had a time-dependent lower risk of revision for instability within the first 1.2 years. In posterior approaches, 10° and 15° liners had a lower risk of revision for instability, with no significant difference between them. The protective effect of lipped over neutral liners was not observed in laterally approached THAs. There were 604 (0.3%) revisions for loosening, but no association between liner geometry and revision for loosening was found., Conclusion: This registry-based study confirms a lower risk of revision for instability in posterior approach THAs with 10° or 15° lipped liners compared to neutral liners, but no significant difference between these lip sizes. A higher revision risk is seen with offset reorientating liners. The benefit of lipped geometries against revision for instability was not seen in laterally approached THAs. Liner geometry does not seem to influence the risk of revision for loosening. Cite this article: Bone Joint J  2021;103-B(12):1774-1782.

Aims: We aimed to evaluate the long-term outcome of highly cross-linked polyethylene (HXLPE) cemented acetabular components and assess whether any radiolucent lines (RLLs) which arose were progressive., Methods: We retrospectively reviewed 170 patients who underwent 187 total hip arthroplasties at two hospitals with a minimum follow-up of ten years. All interventions were performed using the same combination of HXLPE cemented acetabular components with femoral stems made of titanium alloy. Kaplan-Meier survival analysis was performed for the primary endpoint of acetabular component revision surgery for any reason and secondary endpoint of the appearance of RLLs. RLLs that had appeared once were observed over time. We statistically assessed potential relationships between RLLs and a number of factors, including the technique of femoral head autografting and the Japanese Orthopaedic Association score., Results: The mean follow-up period was 13.0 years (10.0 to 16.3). Femoral head autografting was performed on 135 hips (72.2%). One acetabular component was retrieved because of deep infection. No revision was performed for the aseptic acetabular loosening. The Kaplan-Meier survival curve for the primary and secondary endpoints were 98.2% (95% confidence interval (CI) 88.6% to 99.8%) and 79.3% (95% CI 72.8% to 84.6%), respectively. RLLs were detected in 38 hips (21.2%), at a mean of 1.7 years (1 month to 6 years) postoperatively. None of the RLLs were progressive, and the presence of RLLs did not show a significant association with the survival and clinical score. RLLs were more frequently observed in hips without femoral head autografts than in those with autografts., Conclusion: The use of HXLPE cemented acetabular components in total hip arthroplasty demonstrated excellent clinical outcomes after ten years, and no RLLs were progressive, and their presence did not affect the outcome. Femoral head autografting did not negatively impact the acetabular component survival or the appearance of RLLs. Cite this article: Bone Joint J  2021;103-B(10):1604-1610.

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.

Importance: The worldwide population is aging and includes more female individuals than male individuals, with higher rates of total hip arthroplasty (THA) among female individuals. Although research on this topic has been limited to date, several studies are currently under way., Objectives: To evaluate the association between sex and 2-year revision after THA., Design, Setting, and Participants: This cohort study used data from statewide databases in New York and California between October 1, 2015, and December 31, 2018. Patients 18 years or older with osteoarthritis who underwent THA and had sex recorded in the database were included in the analysis., Exposure: Total hip arthroplasty., Main Outcomes and Measures: The outcome of interest was the difference in early, all-cause revision surgery rates after primary THA between women and men. The association of sex with the revision rate was examined using Cox proportional hazards regression analysis., Results: Of 132 826 patients included in the study, 74 002 (55.7%) were women; the mean (SD) age was 65.9 (11.0) years, and the median follow-up time was 1.3 years (range, 0.0-3.0 years). The 2-year revision rate was 2.5% (95% CI, 2.4%-2.6%) among women and 2.1% (95% CI, 2.0%-2.2%) among men. After adjusting for demographic characteristics, comorbidities, and facility volume, a minimal clinically meaningful difference was observed in revision rates despite women having a higher risk of all-cause revision compared with men (hazard ratio, 1.16; 95% CI, 1.07-1.26; P < .001). The risk of revision was increased among women compared with men in the subgroup of patients who were younger than 55 years (hazard ratio, 1.47; 95% CI, 1.20-1.81; P < .001)., Conclusions and Relevance: In this cohort study, no clinically meaningful difference in all-cause revision rates after primary THA was found between men and women at 2-year follow-up. The modest difference in the risk of revision between men and women in a small subgroup of patients younger than 55 years suggests that the risk of revision in this population should be studied further.

We evaluated the clinical and radiographic outcomes of femoral head penetration and total hip arthroplasties with untreated and poly (2-methacryloyloxyethyl phosphorylcholine) (PMPC)-grafted highly cross-linked polyethylene (HXLPE) acetabular liners against 26-, 28-, and 32-mm cobalt-chromium alloy femoral heads 3 years after the index surgery. Three combinations of the articulating surfaces were evaluated in the present study: untreated or PMPC-grafted HXLPE liner against 26- or 28-mm femoral heads (n = 16, 24) [control (26 or 28 mm) and PMPC (26 or 28 mm)] and PMPC-grafted HXLPE liner against 32-mm femoral heads (n = 64) [PMPC (32 mm)]. The clinical outcomes improved at 3 years postoperatively for the groups. No periprosthetic osteolysis or acetabular component migration was detected, and no revision surgery was performed among the groups. The steady-state wear rate of the PMPC (26 or 28 mm) group (0.021 mm/year) was lower than that of the control (26 or 28 mm) group (- 0.015 mm/year); the steady-state wear was under the clinical threshold. In contrast, the steady-state wear rate of the PMPC (32 mm) group (-0.006 mm/year) showed no significant difference when compared to that of the PMPC (26 or 28 mm) group (p < 0.01). The results obtained in the present study clearly demonstrate that PMPC-grafting onto an HXLPE surface improved the wear resistance of acetabular liners, even when coupled with larger femoral heads. Although further follow-up evaluations are required, PMPC-grafted HXLPE acetabular liners may be a promising approach to extend the longevity of artificial joints.

Background: Soft tissue tension is treated as a crucial factor influencing the post-THA dislocation. The femoral offset is regarded as one of the major parameters responsible for the stabilization of the prosthesis. It is unclear which soft tissue is mostly affected by the offset changes., Methods: A finite element model of the hip was created. The model comprised muscles, bones, a stem, the acetabular component and a liner. The muscles were modelled as a Hill-type musculo-tendon nonlinear springs. Nonlinear analyses of the hip flexion and internal rotation were performed for the two values of the femoral stem offset., Results: We observed that the quadratus femoris and gluteus medius produce the largest resisting moment opposing the external load excreted by the surgeon during the intraoperative hip dislocation test., Conclusions: An increased femoral offset increases the stretching of the quadratus femoris muscle significantly and provides the growth of its initial passive force. This muscle serves as a stiff band, providing stabilisation of the hip prosthesis, measured during the simulated intraoperative test., Competing Interests: The authors have declared that no competing interests exist.

Background: This study compared the incidence of osteolysis, aseptic loosening, and revision following use of highly cross-linked polyethylene (HXLPE) or conventional polyethylene (CPE) at medium to long-term (>5 to 15 years) follow-up in primary total hip arthroplasty (THA). Incidences were quantified and compared with regard to age and method of implant fixation., Methods: Using the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines, 12 randomized controlled trials and 18 cohort studies were investigated for evidence-based outcomes following HXPLE and CPE use in 2,539 hips over a 5 to 15-year follow-up., Results: Lower rates of osteolysis, aseptic loosening, and implant revision were reported following use of HXLPE liners. Osteolysis was reduced from 25.4% with CPE to 4.05% with HXLPE in young patients, and from 29.7% to 6.6% in the older patient cohort. Similarities in osteolysis rates were observed when cemented (24.9% for CPE and 6.5% for HXLPE) and uncemented components (32.8% for CPE and 7.1% for HXLPE) were compared. No clear advantage in the type of HXLPE used was observed., Conclusions: Over a follow-up period of up to 15 years, when compared with CPE, use of HXLPE liners reduced the incidence of osteolysis, aseptic loosening, and implant revision, regardless of the fixation method and including in younger and potentially more active patients., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The authors indicated that no external funding was received for any aspect of this work. The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/G272)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Background and purpose - Dislocation of total hip arthroplasties (THA) is often treated with closed reduction and traditionally not registered in orthopedic registers. This study aimed to create an algorithm designed to identify cases of dislocations of THAs with high sensitivity, specificity, and positive predictive value (PPV) based on codes from the Danish National Patient Register (DNPR).Patients and methods - All patients (n = 31,762) with primary osteoarthritis undergoing THA from January 1, 2010 to December 31, 2014 were included from the Danish Hip Arthroplasty Register (DHR). We extracted available data for every hospital contact in the DNPR during a 2-year follow-up period, then conducted a comprehensive nationwide review of 5,096 patient files to register all dislocations and applied codes.Results - We identified 1,890 hip dislocations among 1,094 of the included 31,762 THAs. More than 70 different diagnoses and 55 procedural codes were coupled to the hospital contacts with dislocation. A combination of the correct codes produced a sensitivity of 63% and a PPV of 98%. Adding alternative and often applied codes increased the sensitivity to 91%, while the PPV was maintained at 93%. Additional steps increased sensitivity to 95% but at the expense of an unacceptable decrease in the PPV to 82%. Specificity was, in all steps, greater than 99%.Interpretation - The developed algorithm achieved high and acceptable values for sensitivity, specificity, and predictive values. We found that surgeons in most cases coded correctly. However, the codes were not always transferred to the discharge summary. In perspective, this kind of algorithm may be used in Danish quality registers.

Broken stems are particularly challenging in revision hip arthroplasty, as no standard extraction instruments fit anymore. Well-integrated uncemented stem remnants can be particularly arduous to remove. Stem fatigue failure is not rare with modular stems. Since these are particularly useful in revision hip arthroplasty, increasing numbers of broken stems are to be expected. Usually applied techniques using cortical fenestration distally to the tip of the stem or using an extended transfemoral approach cause supplementary bone defects impairing reconstruction. We present a relatively simple and reproducible revision technique, using a limited standard approach and only regular orthopedic instruments, to extract the remnants of broken uncemented femoral stems in hip arthroplasty. This technique was applied successfully and without complications in 6 cases, permitting eventually the reimplantation of even shorter stems.

Background: Some propitious mid- and long-term studies had been reported for MoM bearings; however, most studies have addressed specific patient groups rather than younger, active patients, who probably represent the most suitable population for investigations on wear and osteolysis. The purpose of this study to evaluate the long-term results of second-generation metal-on-metal cementless total hip arthroplasty (THA) in patients aged <50 years., Methods: From December 1997 to January 2004, primary THA using a metal-on-metal bearing cementless implant was performed in 63 patients (72 hips) aged <50 years. The mean follow-up duration was 18.6 (range, 15.9-22.1) years, and the mean age at initial operation was 39 (range, 22-49) years. Clinical results, complications, survivorship, osteolysis, and aseptic loosening were evaluated., Results: The mean Harris hip score and Western Ontario and McMaster Universities Arthritis Index scores were improved from 57.8 (range, 28-69) points and 73.4 (range, 63-94) points preoperatively to 91.7 (range, 80-100) points and 25.5 points (range, 17-38) points, respectively, at the last follow-up. Osteolysis lesions were found in 12 hips (acetabulum, 6 and femur, 6). The notching occurred on the femoral stem neck occurred in 12 hips. The mean serum cobalt and chromium concentrations were 2.3 (range, 0.2-10.6) μg/L and 1.7 (range, 0.4-8.1) μg/L, respectively, at a mean follow-up of 12.7 years in 32 patients (50.1%). The Kaplan-Meier survivorship curve analysis with revision for any reason as the endpoint revealed that 93.1% survived at 18.6 years' follow-up., Conclusions: Second-generation metal-on-metal cementless THA was found to produce satisfactory clinical and radiographic results with a low revision rate for osteolysis and aseptic loosening in patients aged less than 50 years.

BACKGROUND Patients with hip joint infections in childhood often have many aftereffects of different degrees, regardless of the kind of treatment or natural course. Total hip arthroplasty is currently the most effective treatment for sequelae of childhood hip septic or tuberculous infection. This is a mid-term follow-up study of treatment results of patients who had undergone total hip arthroplasty (THA) with cementless prostheses. MATERIAL AND METHODS We retrospectively analyzed and followed 45 patients (45 hips) who underwent THA with cementless prostheses between 2010 and 2017. There were 45 patients, including 17 men and 28 women. The average age of the patients was 46 years (range, 18-67 years). All hip infections occurred in early childhood or adolescence, and the mean interval between initial infection and THA was 38.2 years (range, 15-60 years). The mean follow-up was 6.1 years (range, 2.7-9.5 years). RESULTS Two patients underwent revision surgery because of loosening of the prosthesis, and 1 patient underwent revision surgery because of a new infection with no relationship with childhood infection during the follow-up. The average Harris hip scores significantly increased from 43.1 to 86.4 (P<0.01), and the average visual analog scale significantly increased from 4.6 to 1.7 (P<0.01). The hip dysfunction and osteoarthritis outcome scores were also significantly changed (P<0.01) at the final follow-up. There were 2 cases of transient sciatic nerve palsy and intraoperative periprosthetic fractures in 3 cases. During follow-up, single revision was performed after 6 years of primary arthroplasty because of aseptic loosening in 2 cases and prosthesis infection in 1 case, which was not related to childhood pathogens. CONCLUSIONS THA for patients with sequelae of hip joint infection has a satisfactory effect that can effectively relieve joint pain and improve hip function. The recurrence rate of infection after either pyogenic infection or tuberculous is very low. The mid-term outcomes of THA in this setting were satisfactory, with high prosthesis survivorship and hip function scores.

Aims: Previous studies have already shown early proximal ingrowth, fast osseous integration, and a stable fit of the uncemented Symax hip stem, with excellent clinical and radiographic performance. Aims were to evaluate cumulative revision rates and reasons for revision of the Symax hip stem using Dutch Arthroplasty Register (LROI) data and to assess possible associations between patient characteristics and revision rate of the Symax hip stem., Patients and Methods: All total hip arthroplasties with the uncemented Symax hip stem registered in the LROI between 2007 and 2017 were included (n = 5,013). Kaplan-Meier survival analysis was performed to assess the cumulative 1, 5 and 7-year revision percentages. Cox proportional hazard regression analysis was performed to assess the association between patient and procedural characteristics, and revision arthroplasty of the stem., Results: Cumulative 1, 5, and 7-year revision rates (with 95% confidence interval (CI)) for revision of any component were 1.5% (CI 1.2%-1.8%), 3.2% (CI 2.7%-3.7%), and 3.8% (CI 3.1%-4.4%) respectively. Cumulative 1, 5, and 7-year stem revision rates of the Symax hip stem were 0.9% (CI 0.6%-1.1%), 1.5% (CI 1.1%-1.9%), and 1.7% (CI 1.3%-2.1%) respectively. Periprosthetic fractures (n = 35) and loosening of the stem (n = 30) were the most common reasons for revision of the stem. Revision of the stem was associated with acute fracture as primary diagnosis (Hazard Ratio (HR) 2.4 (CI 1.3-4.3)), or history of a previous surgery to the affected hip (HR 2.7 (CI 1.4-5.2))., Conclusion: This population-based registry study shows revision rates for the Symax hip stem comparable to those for best performing uncemented total hip arthroplasties in the Netherlands. Primary diagnosis of an acute fracture, and history of previous surgery on the affected hip, were significantly associated risk factors for revision of the Symax hip stem, and we discourage the use of the Symax hip stem in these patients., Competing Interests: The authors have declared that no competing interests exist.

The biological mechanisms involved in aseptic loosening include inflammation-associated and bone resorption-associated processes. Coordinated cellular actions result in biochemical imbalances with devastating consequences for the joint. Given that this condition is not known for showing systemic signs, we investigated whether circulating levels of inflammation-related proteins are altered in patients with aseptic loosening. Our study included 37 patients who underwent revision surgery due to hip osteolysis and aseptic loosening and 31 patients who underwent primary total hip arthroplasty. Using antibody arrays, we evaluated the serum levels of 320 proteins in four patients from each group. The results showed differences in insulin-like growth factor-binding protein 1 (IGFBP-1) concentrations, which we then quantified using enzyme-linked immunosorbent assay tests in all study patients. The results confirmed that serum IGFBP-1 concentrations were higher in the revision surgery patients than in the hip arthroplasty patients. In vitro studies showed that exposure of human osteoblasts to titanium particles induced an IGFBP-1 release that further increased when exposure to particles was performed in media conditioned by human M1 macrophages. These findings suggest that elevated serum IGFBP-1 levels in patients with aseptic loosening can arise from increased local IGFBP-1 production in the inflammatory environment of the periprosthetic bed.

Background and purpose - Little is known about the long-term migration pattern of cementless stems in total hip arthroplasty (THA). Furthermore, the role of bioactive coatings in fixation, and thus migration, remains uncertain. Hydroxyapatite (HA) is the most commonly used bioactive coating. However, delamination of the coating might induce loosening. Alternatively, fluorapatite (FA) has proved to be more thermostable than HA, thereby potentially increasing longevity. We assessed the long-term migration of cementless stems with different coatings using radiostereometric analysis (RSA), thereby establishing a reference for acceptable migration. Patients and methods - 61 THAs in 53 patients were randomized to receive either a HA, FA, or uncoated Mallory-Head Porous stem during the years 1992 to 1994. Primary outcome was stem migration measured using RSA and secondary outcome was the Harris Hip Score (HHS). Evaluation took place preoperatively and postoperatively on the second day, at 6, 12, 25 and 52 weeks, and annually thereafter. At the 25-year follow-up, 12 patients (17 THAs) had died and 1 patient (1 THA) was lost to follow-up. Due to the high number of missing second-day postoperative RSA radiographs, the 1-year postoperative RSA radiograph was used as baseline for the comparative analyses. Results - Mean follow-up was 17 years (SD 6.6). All stems showed initial rapid migration with median subsidence of 0.2 mm (-0.1 to 0.6) and median retroversion of 0.9° (-3.2 to 2) at 12 months, followed by stable migration reaching a plateau phase. No stem was revised, albeit 1 stem showed continuous subsidence up to 1.5 mm. Comparing the different coatings, we could not find a statistically significant difference in overall 25-year migration (p-values > 0.05). Median subsidence at 15-year follow-up was for HA -0.1 mm (-0.4 to 0.2), for FA 0 mm (-0.1 to 0.2), and for uncoated stems 0.2 mm (-0.1 to 0.5). Median internal rotation at 15-year follow-up was for HA not available, for FA 1.1° (-0.5 to 2.6), and for uncoated stems 0° (-0.5 to 0.4). HHS were also comparable (p-values > 0.05), with at 15-year follow-up for HA 85 points (41-99), for FA 76 points (61-90), and for uncoated stems 79 points (74-90). Interpretation - The long-term migration pattern of cementless stems using different bioactive coatings has not previously been described. No beneficial effect, or side effect at long-term follow-up of bioactive coatings, was found. The provided migration data can be used in future research to establish thresholds for acceptable migration patterns cementless stem designs.

Background and purpose - The use of trabecular metal cups in primary total hip arthroplasty (THA) is increasing, despite the survival of Continuum cups being slightly inferior compared with other uncemented cups in registries. This difference is mainly explained by a higher rate of dislocation revisions. Cup malpositioning is a risk factor for dislocation and, being made of a highly porous material, Continuum cups might be more difficult to position. We evaluated whether Continuum cups had worse cup positioning compared with other uncemented cups. Patients and methods - Based on power calculation, 150 Continuum cups from 1 center were propensity score matched with 150 other uncemented cups from 4 centers. All patients had an uncemented stem, femoral head size of 32 mm or 36 mm, and BMI between 19 and 35. All operations were done for primary osteoarthrosis through a posterior approach. Patients were matched using age, sex, and BMI. Cup positioning was measured from anteroposterior pelvic radiograph using the Martell Hip Analysis Suite software. Results - There was no clinically relevant difference in mean inclination angle between the study group and the control group (43° [95% CI 41-44] and 43° [CI 42-45], respectively). The study group had a larger mean anteversion angle compared with the control group, 19° (CI 18-20) and 17° (CI 15-18) respectively. Interpretation - Continuum cups had a greater anteversion compared with the other uncemented cups. However, the median anteversion was acceptable in both groups and this difference does not explain the larger dislocation rate in the Continuum cups observed in earlier studies.

Background and purpose - Despite the good results after total hip arthroplasty (THA), new implants are continuously being developed to improve durability. The Echo Bi-Metric (EBM) THA stem is the successor to the Bi-Metric (BM) THA stem. The EBM stem includes many of the features of the BM stem, but minor changes in the design might improve the clinical performance. We compared the migration behavior with radiostereometric analysis (RSA) of the EBM stem and the BM stem at 24 months and evaluated the clinical outcome. Patients and methods - We randomized 62 patients with osteoarthritis (mean age 64 years, female/male 28/34) scheduled for an uncemented THA to receive either an EBM or a BM THA stem. We performed RSA within 1 week after surgery and at 3, 6, 12, and 24 months. The clinical outcome was evaluated using Harris Hip Score (HHS) and Oxford Hip Score (OHS). Results - At 24 months, we found no statistically significant differences in migration between the two implants. During the first 3 months both the EBM and the BM stems showed visible subsidence (2.5 mm and 2.2 mm respectively), and retroversion (2.5° and 2.2° respectively), but after 3 months this stabilized. The expected increase in HHS and OHS was similar between the groups. Interpretation - The EBM stem showed a migration at 24 months not different from the BM stem, and both stems display satisfying clinical results.

Background and purpose - Survivorship of total hip arthroplasty (THA) with the ultra-high molecular weight polyethylene (UHMWPE) monoblock cup has been limited due to periprosthetic osteolysis and aseptic loosening, secondary to wear of the UHMWPE. In response, a vitamin E blended highly cross-linked polyethylene (HXLPE) cup was developed. This study set out to compare the wear and clinical 6-year outcomes of vitamin E blended HXLPE with UHMWPE in an isoelastic monoblock cup in patients with hip osteoarthritis who underwent uncemented THA. The 2-year results have been reported previously. Patients and methods - For this randomized controlled trial 199 patients were included. 102 patients received the vitamin E blended HXLPE uncemented acetabular cup and 97 patients the uncemented UHMWPE monoblock cup. Clinical and radiographic parameters were obtained preoperatively, directly postoperatively, and at 3, 12, 24, and 72 months. Wear rates were compared using the femoral head penetration (FHP) rate. Results - 173 patients (87%) completed the 6-year follow-up. The mean NRS scores for rest pain, load pain, and patient satisfaction were 0.3 (SD 1), 0.6 (SD 1), and 8.6 (SD 1) respectively. The mean Harris Hip Score was 93 (SD 12). The FHP rate was lower in the vitamin E blended HXLPE cup (0.028 mm/year) compared with the UHMWPE cup (0.035 mm/year) (p = 0.002). No adverse reactions associated with the clinical application of vitamin E blended HXLPE were observed. 15 complications occurred, equally distributed between the two cups. The 6-year survival to revision rate was 98% for both cups. There was no aseptic loosening. Interpretation - This study shows the superior performance of the HXLPE blended with vitamin E acetabular cup with clinical and radiographic results similar to the UHMWPE acetabular cup.

Purpose: Although a cementless modular prosthesis has shown reliable results, cases of unstable fixation and revision due to aseptic loosening were observed in our institute. The purpose of this study was to clarify the causes of unstable fixation of the prosthesis., Methods: A total of 144 patients (154 hips) who underwent total hip arthroplasty using the modular prosthesis were retrospectively investigated. For the cohort study, 97 patients (104 hips) were included. The femoral component survival rate and sleeve fixation were assessed at a minimum follow-up of 5 years. Patients were divided into 2 groups, including stable and unstable fixation groups, by sleeve fixation. Clinical and radiographic outcomes were compared., Results: The Kaplan-Meier survival rate at 9 years was 93% with revision for any reason as the endpoint in study cohort. The reasons for revision were recurrent dislocation (1 hip) and aseptic loosening of the stem (5 hips). A total of 88 hips (84.6%) showed stable fixation, and 16 hips (15.4%) showed unstable fixation at final follow-up. There was no significant difference in clinical outcomes between the 2 groups at final follow-up. The canal flare index was significantly higher, and the canal filling ratio was significantly lower in the unstable fixation group., Conclusion: Although the modified modular prosthesis was useful for treating anatomically difficult patients, we need to pay attention to both proximal/distal mismatch of the intramedullary canal and the canal filling ratio to achieve stable fixation and good long-term results.

Selective supplementation of acetabular component fixation with a screw during primary total hip arthroplasty (THA) assumes that the surgeon can detect when an acetabular component needs additional stability. In contrast, nonselective screw users do not alter their practice based on their interpretation of stability and either use screws all or none of the time. We aimed to determine the effect of selective screw use on aseptic acetabular component loosening. We retrospectively reviewed aseptic failures of acetabular components after primaty THA. We compared the survivorship of selective and nonselective supplementation of acetabular fixation with respect to time to revision, obesity, and screw use. Selective screw use (n = 16) was associated with earlier acetabular component aseptic loosening (median: 1.9 years; interquartile range [IQR]: 1.1-5.0) compared to nonselective screw use (n = 22; median: 5.6 years; IQR: 2.0-15.3; P = .010). Selective screw use was independently associated with earlier revision after adjusting for patient obesity. Obesity was associated with selective screw use in 50% of the cases vs 14% of nonselective cases (odds ratio: 6.3; confidence interval: 1.2-25.2; P = .028), possibly reflecting the increased difficulty in achieving acetabular component stability in this and other settings with compromised bone. Surgeons should carefully assess component stability at time of primary THA. If the acetabulum is not stable, the addition of screws alone may not be sufficient for acetabular component stability., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Introduction: Little is known about the association between well-fixed polished tapered cemented stems (PTCS) implanted by the line-to-line technique and changes of stem migration, or the change of functional anteversion of the femur after total hip arthroplasty (THA)., Materials and Methods: This retrospective study included 422 two-stage bilateral primary THAs performed using PTCS implanted by the line-to-line technique. CT scans were made on both the target side (first postoperative CT) and on the contralateral side (second postoperative CT) 1 week postoperatively. The mean follow-up was 7.8 months. CT data for each scan were transferred to 3D template software (Zed hip, Lexi, Japan). The postoperative changes of anatomical stem anteversion (ASA), functional femoral anteversion (FFA), and stem subsidence were evaluated., Results: A total of 20 THAs with CT scans were available on 3D template software. The ASA and the FFA had migrated - 0.68° ± 0.62° and - 5.5° ± 9.7°, respectively, over the follow-up period. A significant positive correlation was observed between the change of subsidence and ASA (r 2  = 0.34, p = 0.007), between the FFA on the second postoperative CT and ASA on the first postoperative CT (r 2  = 0.26, p = 0.02) and between the FFA on the second postoperative CT and FFA on the first postoperative CT (r 2  = 0.52, p = 0.0003)., Conclusion: This study indicates that the change in axial rotation of a PTCS implanted by the line-to-line technique was less than that reported by other studies and the preoperative external rotation contracture was substantially improved after THA.

Background: Numerous quantitatively biomechanical studies measuring the fixation stability of femoral stem using micromotions at the bone-implant interfaces in different directions and levels remain inconclusive. This network meta-analysis performed systematically aims to explore the rank probability of micromotions at the bone-implant interfaces based on biomechanical data from studies published., Methods: Two electronic databases, PubMed/MEDLINE and Embase, were utilized to retrieve biomechanical studies providing the data of micromotions at the bone-stem interfaces. After screening and diluting out, the studies that met inclusion criteria will be utilized for statistical analysis. In order to contrast the stability of commonness and differences of the different parts of the femoral stem, the horizontal and vertical comparison of micromotions at the bone-implant interfaces were conducted using the pooled evaluation indexes including the mean difference (MD) and the surface under the cumulative ranking (SUCRA) curve, while inconsistency analysis, sensitivity analysis, subgroup analyses, and publication bias were performed for the stability evaluation of outcomes., Results: Screening determined that 20 studies involving a total of 249 samples were deemed viable for inclusion in the network meta-analysis. Tip point registered the highest micromotions of 13 measurement points. In the horizontal level, the arrangements of 4 measurement points at the proximal (P1-P4), middle (P5-P8) and distal part of the stem (P9-P12) were P1 = P2 = P3 = P4, P7 > P8 > P6 = P5 and P10 ≥ P12 = P9 = P11, respectively. In the vertical level, the arrangements of 3 measurement points at the anterior, posterior, medial, and lateral directions was P9 > P5 = P1, P10 > P6 > P2, P11 > P7 > P3, and P12 > P8 > P4, respectively., Conclusion: The network meta-analysis seems to reveal that the distal part of the femoral stem is easier to register higher micromotion, and tip point of femoral stem registers the highest micromotions.

The direct anterior approach (DAA) for total hip arthroplasty (THA) is a technique popular among some arthroplasty surgeons. There is currently a paucity of data regarding reasons for failure of THA using the DAA. The authors conducted a retrospective review of prospectively collected data on 56 patients who underwent revision THA at their institution after failing primary THA that was performed through a DAA either at their institution (n=8) or elsewhere (n=48) from January 1, 2010, to June 1, 2017. Patients were grouped by modes of failure and compared using patient characteristics, surgical factors, and radiographic outcomes. Total hip arthroplasties performed through the DAA failed due to infection in 21 (38%) patients, aseptic/mechanical loosening in 14 (25%) patients, intraoperative fracture in 6 (11%) patients, postoperative fracture in 6 (11%) patients, tendinitis or pain of unknown etiology in 3 (5%) patients, metallosis in 3 (5%) patients, instability/dislocation in 2 (4%) patients, and leg length discrepancy in 1 (2%) patient. Patients who underwent revision due to unrecognized intraoperative fracture had a lower body mass index (BMI) and weight than patients who had failure due to postoperative fracture, aseptic loosening, or infection. The 4 most common modes of failure included infection, aseptic loosening, unrecognized intraoperative fracture, and postoperative fracture. Together, these made up 84% of failed DAA THAs. Patients with a lower BMI are more likely to have failure due to intraoperative fractures. Patients with a higher BMI are more likely to have failure due to postoperative fracture, aseptic loosening, or infection. [Orthopedics. 2020;43(4);239-244.]., (Copyright 2020, SLACK Incorporated.)

Background: Both cylindrical and tapered stems are commonly used in revision total hip arthroplasty. However, whether the geometry of prosthesis stem has an effect on patient prognosis is unclear. We assume that the tapered stem results in better clinical outcome than the cylindrical stem., Methods: A multicenter review of 120 femoral revisions with Paprosky I, II, and III defects using cobalt chrome cylindrical stem (54 hips) or titanium tapered stem (66 hips) was performed with an average follow-up of 6 years. Demographic data were comparable between groups., Results: No significant group differences were found in surgery time, bleeding volume, postoperative Harris Hip Score, level of overall satisfaction, and 8-year cumulative survival. However, intraoperative fractures occurred significantly less in the tapered group (4.5%) than in the cylindrical group (14.8%), and stem subsidence was significantly less in the tapered group (2.17 mm) than in the cylindrical group (4.17 mm). A higher ratio of bone repair and lower bone loss were observed in the tapered group compared with the cylindrical group. The postoperative thigh pain rate was higher in the cylindrical group (12.9%) than in the tapered group (4.5%)., Conclusion: Both cylindrical stem and tapered stem can achieve satisfactory mid-term clinical results in revision total hip arthroplasty. The tapered stem has better bone restoration of proximal femur, lower incidence of intraoperative fractures, and lower postoperative thigh pain rate compared with the cylindrical stem.

Rationale: Dislocation, wear, metallosis, and implant loosening are well-known complications of a failed total-hip arthroplasty (THA), and acetabular liner dissociation is an uncommon but catastrophic complication. To our knowledge, this is the first description of metallosis due to acetabular liner dissociation, but not presenting as a result of wear of a metal-on-metal articulation and a polyethylene liner of other articulation., Patient Concerns: We described a 61-year-old man who had a 2-year history of pain in the right groin region after THA. Postoperative period of primary THA was uneventful. However, he did not undergo postoperative follow-up, and often participated in strenuous sports activities including mountain climbing and long-distance running., Diagnosis: Radiographs demonstrated superior subluxation of the femoral head and direct articulation and abrasion wear of the ceramic femoral head on the cup. Preoperative laboratory data revealed no signs of infection., Interventions: We performed revision THA using a direct lateral approach with ceramic-on-ceramic hip prosthesis., Outcomes: Postoperatively, the patient wore a hip orthosis for 6 weeks to prevent dislocation but was allowed full weight bearing. At 1-year follow-up, there was no recurrence of hip pain., Lessons: Wear of THA components can result in catastrophic failure of the implants and significant soft-tissue metallosis. Therefore, regular postoperative follow-up is necessary for early intervention, even in those with asymptomatic hips.

Background and purpose - The introduction of new total hip replacements (THRs) is known to be associated with an increased risk for complications. On completion of a competitive procurement process, a new uncemented cup system was introduced into general use at our institution in 2016. We launched this study after the introduction to assess (1) the incidence of early dislocations of the old (Pinnacle) and the new (Continuum) cup systems, and (2) whether the cup design would affect the risk for dislocation.Patients and methods - We assessed the incidence of dislocations after 1,381 primary THRs performed at our institution during 2016. Also, the effect of the cup system (Pinnacle, Continuum with neutral liner, Continuum with elevated rim liner) on dislocation rates was analyzed using a multivariable regression model.Results - 47 (3.4%) early dislocations were identified. The incidence of dislocations was 1.3% for the Pinnacle, 5.1% for the Continuum with neutral liner, and 1.2% for the Continuum with elevated rim liner. The Continuum with neutral liner was found to have an increased risk for dislocations compared with the Pinnacle (aOR 5, 95% CI 1.4-17). However, when an elevated rim liner was used with the Continuum, the risk for dislocation between the Continuum and the Pinnacle was similar.Interpretation - Our results emphasize the need for both careful consideration before the introduction of new implants and the systematic monitoring of early outcomes thereafter. The elevated rim liner should be preferred for use with the Continuum cup because of the poor coverage of the neutral liner that may result in dislocations.

Aims: The aim of this study was to determine if a three-month course of microorganism-directed oral antibiotics reduces the rate of failure due to further infection following two-stage revision for chronic prosthetic joint infection (PJI) of the hip and knee., Methods: A total of 185 patients undergoing a two-stage revision in seven different centres were prospectively enrolled. Of these patients, 93 were randomized to receive microorganism-directed oral antibiotics for three months following reimplantation; 88 were randomized to receive no antibiotics, and four were withdrawn before randomization. Of the 181 randomized patients, 28 were lost to follow-up, six died before two years follow-up, and five with culture negative infections were excluded. The remaining 142 patients were followed for a mean of 3.3 years (2.0 to 7.6) with failure due to a further infection as the primary endpoint. Patients who were treated with antibiotics were also assessed for their adherence to the medication regime and for side effects to antibiotics., Results: Nine of 72 patients (12.5%) who received antibiotics failed due to further infection compared with 20 of 70 patients (28.6%) who did not receive antibiotics (p = 0.012). Five patients (6.9%) in the treatment group experienced adverse effects related to the administered antibiotics severe enough to warrant discontinuation., Conclusion: This multicentre randomized controlled trial showed that a three-month course of microorganism-directed, oral antibiotics significantly reduced the rate of failure due to further infection following a two-stage revision of total hip or knee arthroplasty for chronic PJI. Cite this article: Bone Joint J 2020;102-B(6 Supple A):3-9.

Background and purpose - The uncemented Symax hip stem has shown early proximal ingrowth as result of the BONIT-hydroxyapatite (HA) coating and the distal DOTIZE surface treatment. We evaluated 2-year postoperative radiostereometric analysis (RSA) migration of the Symax hip stem in THA patients. We also investigated the correlation between migration at 4 weeks and clinical outcomes after 2 years.Patients and methods - Patients in a 2-year clinical follow-up single-centre RSA randomized controlled trial were randomized to 2 different cup designs. All 45 patients received a Symax hip stem. RSA migration patterns of the Symax hip stem is presented here as a single cohort. RSA examinations were performed postoperatively, but before weight-bearing, and subsequently after 1, 3, 6, 12, and 24 months. Clinical outcomes and radiographic evaluations were assessed 3, 6, 12, and 24 months postoperatively.Results - During the first 4 weeks, the Symax hip stem subsided, rotated into retroversion, and translated posteriorly, after which the migration ceased and the prosthesis stabilized. All clinical outcomes improved from preoperatively to 2 years. There was no clinically or statistically significant correlation between subsidence and retroversion at 4 weeks and clinical outcomes after 2 years.Interpretation - RSA evaluation of the uncemented Symax hip stem confirms that the design principles and coating properties lead to early stabilization of the stem, as early as 4 weeks postoperatively. There was no correlation between subsidence and retroversion at 4 weeks and clinical outcomes after 2 years. Based on the predictive potential of the RSA technique, we anticipate excellent long-term survival of this hip stem.

Aims: Dislocation remains a significant complication after total hip arthroplasty (THA), being the third leading indication for revision. We present a series of acetabular revision using a dual mobility cup (DMC) and compare this with our previous series using the posterior lip augmentation device (PLAD)., Methods: A retrospective review of patients treated with either a DMC or PLAD for dislocation in patients with a Charnley THA was performed. They were identified using electronic patient records (EPR). EPR data and radiographs were evaluated to determine operating time, length of stay, and the incidence of complications and recurrent dislocation postoperatively., Results: A total of 28 patients underwent revision using a DMC for dislocation following Charnley THA between 2013 and 2017. The rate of recurrent dislocation and overall complications were compared with those of a previous series of 54 patients who underwent revision for dislocation using a PLAD, between 2007 and 2013. There was no statistically significant difference in the mean distribution of sex or age between the groups. The mean operating time was 71 mins (45 to 113) for DMCs and 43 mins (21 to 84) for PLADs (p = 0.001). There were no redislocations or revisions in the DMC group at a mean follow-up of 55 months (21 to 76), compared with our previous series of PLAD which had a redislocation rate of 16% (n = 9) and an overall revision rate of 25% (n = 14, p = 0.001) at a mean follow-up of 86 months (45 to 128)., Conclusion: These results indicate that DMC outperforms PLAD as a treatment for dislocation in patients with a Charnley THA. This should therefore be the preferred form of treatment for these patients despite a slightly longer operating time. Work is currently ongoing to review outcomes of DMC over a longer follow-up period. PLAD should be used with caution in this patient group with preference given to acetabular revision to DMC. Cite this article: Bone Joint J 2020;102-B(4):423-425.

Background and purpose - The increasing use of hip arthroplasties in young patients will inevitably lead to more revision procedures at younger ages, especially as the outcome of their primary procedures is inferior compared with older patients. However, data on the outcome of revision hip arthroplasty in young patients are limited. We determined the failure rates of revised hip prostheses performed in patients under 55 years using Dutch Arthroplasty Register (LROI) data.Patients and methods - All 1,037 revised hip arthroplasty procedures in patients under 55 years at the moment of revision registered in the LROI during the years 2007-2018 were included. Kaplan-Meier survival analyses were used to calculate failure rates of revised hip arthroplasties with endpoint re-revision for any reason. Competing risk analyses were used to determine the probability of re-revision for the endpoints infection, dislocation, acetabular and femoral loosening, while other reasons for revisions and death were considered as competing risks.Results - Mean follow-up of revision procedures was 3.9 years (0.1-12). 214 re-revisions were registered. The most common reason for the index revision was dislocation (20%); the most common reason for re-revision was infection (35%). The 5-year failure rate of revised hip prostheses was 22% (95% CI 19-25), and the 10-year failure rate was 28% (CI 24-33). The 10-year cumulative failure rates of index revisions with endpoint re-revision for infection was 7.8% (CI 6.1-9.7), acetabular loosening 7.0% (CI 4.1-11), dislocation 3.8% (CI 2.6-5.2), and femoral loosening 2.7% (CI 1.6-4.1). The 10-year implant failure rate of index revisions for infection was 45% (CI 37-55) with endpoint re-revision for any reason.Interpretation - Failure rate of revised hip prostheses in patients under 55 years is worrisome, especially regarding index revisions due to infection. This information facilitates realistic expectations for these young patients at the time of primary THA.

Background and purpose - Total hip arthroplasty (THA) is increasing as treatment of displaced femoral neck fractures. Several studies compare hemiarthroplasty (HA) with THA, but results vary and few studies report on medical complications. We examined the outcome of THA and HA with a focus on medical complications, hip complications, and death.Patients and methods - Data from the Swedish Hip Arthroplasty Register on 30,953 acute hip fracture patients treated with cemented THA or HA in 2005-2011 were cross-matched with Statistics Sweden for socioeconomic data and with the National Patient Register for diagnostic codes representing medical complications within 180 days or hip complications within the study period. Propensity score matching was used to create comparable groups based on age, sex, income, level of education, marital status, Elixhauser index, and year of surgery. Logistic regression models were created for each outcome.Results - 81% were treated with HA, 73% and 71% were female (HA and THA respectively). Matching resulted in 2 groups of 5,815 patients each. THA was associated with fewer medical complications (OR = 0.83; 95% CI 0.76-0.91) and lower 1-year mortality (OR = 0.42; CI 0.38-0.48), but more hip complications (OR = 1.31; CI 1.20-1.43).Interpretation - THA as treatment of hip fracture was associated with more hip-related complications than HA. The results on mortality and medical complications are, rather, influenced by residual confounding than by the implant design per se. An expansive use of THAs for hip fracture treatment, at the expense of HAs, is not recommended based on our findings if hip complications are to be avoided.

Aims: To compare long-term survival of all-cemented and hybrid total hip arthroplasty (THA) using the Exeter Universal stem., Methods: Details of 1,086 THAs performed between 1999 and 2005 using the Exeter stem and either a cemented (632) or uncemented acetabular component (454) were collected from local records and the New Zealand Joint Registry. A competing risks regression survival analysis was performed with death as the competing risk with adjustments made for age, sex, approach, and bearing., Results: There were 61 revisions (9.7%; 0.82 revisions/100 observed component years, (OCYs)) in the all-cemented group and 18 (4.0%; 0.30/100 OCYs) in the hybrid group. The cumulative incidence of revision at 18 years was 12.1% for cemented and 5.2% for hybrids. There was a significantly greater risk of revision for all-cemented compared with hybrids (unadjusted sub-hazard ratio (SHR) 2.44; p = 0.001), and of revision for loosening, wear, or osteolysis (unadjusted SHR 3.77; p < 0.001). After adjustment, the increased risk of all-cause revision did not reach significance at age 70 years and above. The advantage for revision for loosening, wear, and osteolysis remained at all ages., Conclusion: This study supports the use of uncemented acetabular fixation when used in combination with the Exeter stem with improved survivorship for revision for aseptic loosening, wear, and osteolysis at all ages and for all-cause revision in patients less than 70 years. Cite this article: Bone Joint J 2020;102-B(4):414-422.

Our aim was to investigate the association of inflammasome polymorphisms NLRP3 rs35829419 (p. Q705K) and CARD8 rs2043211 (p. C10X) with aseptic loosening of total hip endoprostheses. We asked whether patients with the loosening of total hip arthroplasty earlier than 15 years after primary implantation had a higher proportion of the polymorphisms Q705K and C10X in comparison to subjects without loosening. A retrospective case-control study compared 36 patients with total hip endoprosthesis loosening earlier than 15 years after primary implantation and 51 control subjects with unloosened total hip endoprostheses, matched for gender, age, and follow-up period. Buccal mucosa samples were used for genomic DNA analysis and genotyped for NLRP3 rs35829419 and CARD8 rs2043211 using a fluorescence-based competitive allele-specific real-time polymerase chain reaction. The proportion of subjects with both wild-type NLRP3 and CARD8 (i.e., without Q705K or C10X) was considerably higher in the control group when compared with patients with early total hip arthroplasty loosening (49% vs. 28%; p = 0.05). After adjustment for gender, age, and follow-up, patients with combined wild type of both NLRP3 and CARD8 had significantly smaller odds for early implant loosening (odds ratio 0.33, p = 0.02). Investigated polymorphisms may influence several inflammatory pathways and contribute to the loosening of artificial implants with potential clinical significance for the appropriate selection of patients and endoprostheses when planning elective total hip arthroplasty. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:417-421, 2020., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Ceramic acetabular liner fracture is a rare complication and requires early revision surgery to avoid abrasive damaging of metal components by ceramic particles. Chromium-cobalt femoral head can be used in revision surgery if only fractured ceramic particles are completely removed because the abrasive effect of ceramic debris is more pronounced on metal head compared to ceramic head. In this article, we report a 50-year-old male patient of delayed acetabular liner fracture in which we used a ceramic head that is more resistant to residue ceramic particles. We assessed the patient by using computed tomography (CT) to locate the ceramic particles. By using CT imaging, we can detect which ceramic particles pose high morbidity risk for debridement.

Objectives: This study aims to present our experience in the management of fractured femoral stems after primary and revision hip replacements by evaluating the clinical and radiographic characteristics and determining the effectiveness of the extraction methods., Patients and Methods: A total of 15 patients (5 males, 10 females; mean age 65.9 years; range, 49 to 87 years) who underwent revision hip replacement due to a fractured femoral stem between January 2005 and December 2019 were included in this retrospective study. The mechanisms and risk factors for failure as well as methods applied to extract fractured stem were analyzed through clinical and radiographic data., Results: Nine patients had fractured cemented femoral stems, while six patients had fractured fully porous coated cementless revision stems. Lack of proximal buttress in distally fixed femoral stems was detected in 11 patients and identified as the predominant mechanism resulting in fracture. The proximal extraction method with conventional revision instrumentation, the cortical window technique, and extended trochanteric osteotomy (ETO) were used in three, seven, and five cases, respectively., Conclusion: Our results demonstrated that the lack of proximal buttress is the most common reason for femoral stem fracture. Moreover, the proximal extraction method was mostly ineffective in fully porous femoral stems. A step-by-step approach should be considered for the extraction of a broken stem. The cortical window method can be considered as the second step if proximal extraction methods fail, and ETO should be considered at the last step if all techniques fail.

Background: Unrecognized periprosthetic joint infections are a concern in revision surgery for aseptic failure (AF) after total hip (THA) or knee (TKA) arthroplasties. A gold diagnostic standard does not exist. The aim of the current study was to determine the prevalence of unrecognized periprosthetic joint infection (PJI) in a cohort of revision for AF, using an experimental diagnostic algorithm., Methods: The surgeons' suspicion of AF was based primarily on patient history and clinical evaluation. X-ray imaging was used to reveal mechanical problems. To rule out an infectious aetiology standard blood biochemical tests were ordered in most patients. Evaluation followed the existing practice in the institute. Cases were included if revision surgery was planned for suspected AF. Intraoperatively, five synovial tissue biopsies were obtained routinely. PJI was defined as ≥3 positive cultures with the same microorganism(s). Patients were followed for 1 year postoperatively. Protocol samples included joint fluid, additional synovial tissue biopsies, bone biopsy, swabs from the implant surface, and sonication of retrieved components. Routine and protocol samples were cultured with extended incubation (14 days) and preserved for batchwise 16S rRNA gene amplification. Patients were stratified based on culture results and a clinical status was obtained at study end., Results: A total of 72 revisions were performed on 71 patients (35 THA and 37 TKA). We found five of 72 cases of unrecognized PJI. Extended culture and protocol samples accounted for two of these. One patient diagnosed with AF was treated for a PJI during follow-up. The remaining patients did not change status from AF during follow-up., Conclusions: We found a low prevalence of unrecognized periprosthetic joint infections in patients with an AF diagnosis. The algorithm strengthens the surgeons' preoperative diagnosis of a non-infective condition. Evaluation for a failing TKA or THA is complex. Distinguishing between AF and PJI pre-operatively was a clinical decision. Our data did not support additional testing in routine revision surgery for AF.

Background: Early femoral stem subsidence following a cementless THA is correlated with aseptic loosening of the femoral component. The short femoral stems allow bone sparing and implantation through a minimally invasive approach; however, due to their metaphyseal anchoring, they might demonstrate different subsidence pattern than the conventional stems., Methods: In this prospective single-center study, a total of 68 consecutive patients with an average age of 63 years, and a minimum follow-up of 5 years following a cementless THA with a metaphyseal-anchored short femoral stem were included. The femoral stem subsidence was evaluated using "Ein Bild Roentgen Analyse" (EBRA)., Results: Average stem migration was 0.96 +/- 0.76 mm at 3 months, 1.71 +/- 1.26 mm at 24 months, and 2.04+/- 1.42 mm at last follow-up 60 months postoperative. The only factor that affected migration was a stem size of 6 or more (r 2  = 5.74; p = 0.039). Subdivision analysis revealed, that only in females migration appeared to be affected by stem size irrespective of weight but not in men (female stem size of 6 or more vs. less (Difference = - 1.48 mm, R 2  = 37.5; p = 0.001). Migration did not have an impact on clinical outcome measures., Conclusions: The examined metaphyseal-anchored short femoral stem showed the highest subsidence within the first 3 months postoperative, the implant began to stabilize at about 24 months but continued to slowly migrate with average total subsidence of 2.04 mm at 5 years following the THA. The amount of stem subsidence was not associated with worse clinical outcomes such as HHS, patient satisfaction, or pain.

Total hip arthroplasty (THA) alleviates hip pain and improves joint function. Current implant design permits long-term survivorship of THAs, but certain metal-on-metal (MoM) articulations can portend catastrophic failure due to adverse local tissue reactions (ALTR). Here, we identified biological and molecular differences between periacetabular synovial tissues of patients with MoM THA failure undergoing revision THA compared to patients undergoing primary THA for routine osteoarthritis (OA). Analysis of tissue biopsies by RNA-sequencing (RNA-seq) revealed that MoM patient samples exhibit significantly increased expression of immune response genes but decreased expression of genes related to extracellular matrix (ECM) remodeling. Thus, interplay between local tissue inflammation and ECM degradation may account for the pathology and compromised clinical outcomes in select patients with MoM implants. We conclude that adverse responses of host tissues to implant materials result in transcriptomic modifications in patients with MoM implants that permit consideration of strategies that could mitigate ECM damage., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background and purpose - Previous small studies have suggested that delivery does not adversely affect the survivorship of total hip replacement (THR). We investigated whether delivery after primary THR affects hip implant survivorship in a large population-based study sample Patients and methods - In this register-based nationwide cohort study, all women aged 15-45 who underwent primary THR in Finland from 1987 to 2007 were included from the Finnish Arthroplasty Register. Data on deliveries were obtained from the medical birth register. After primary THR, 111 women (133 THRs) delivered and formed the delivery group. In the reference group, 1,878 women (2,343 THRs) had no deliveries. We used Kaplan-Meier analysis with 95% confidence intervals (CI) to study implant survivorship at 6 and 13 years, and Cox multiple regression to assess survival and hazard ratios (HRs), with revision for any reason as an endpoint with adjustment for age, rheumatoid arthritis, and stem and cup fixation. Results - 51 (38%) revisions were recorded in the delivery group and 645 (28%) revisions in the reference group. The 6-year implant survivorship was 91% (CI 85-96) in the delivery group and 88% (CI 87-90) in the reference group. The 13-year survival rates were 50% (CI 39-62) and 61% (CI 59-64). The adjusted HR for revision after delivery was 0.7 (CI 0.4-1.2) in ≤ 6.8 years' follow-up and 1.1 (CI 0.8-1.6) in > 6.8 years' follow-up. Interpretation - Based on the findings in this nationwide study of hip replacement in fertile-aged women, delivery does not seem to decrease THR implant survivorship; women should not be afraid of or avoid becoming pregnant after THR.

Background and purpose - Uncemented stems are increasingly used in revision hip arthroplasty, but only a few studies have analyzed the outcomes of uncemented and cemented revision stems in large cohorts of patients. We compared the results of uncemented and cemented revision stems. Patients and methods - 1,668 uncemented and 1,328 cemented revision stems used in first-time revisions due to aseptic loosening between 1999 and 2016 were identified in the Swedish Hip Arthroplasty Register. Kaplan-Meier analysis was used to investigate unadjusted implant survival with re-revision for any reason as the primary outcome. Hazard ratios (HR) for the risk of re-revision were calculated using a Cox regression model adjusted for sex, age, head size, concomitant cup revision, surgical approach at primary and at index revision surgery, and indication for primary total hip arthroplasty. Results - Unadjusted 10-year survival was 85% (95% CI 83-87) for uncemented and 88% (CI 86-90) for cemented revision stems. The adjusted HR for re-revision of uncemented revision stems during the first year after surgery was 1.3 (CI 1.0-1.6), from the second year the HR was 1.1 (CI 0.8-1.4). Uncemented stems were most often re-revised early due to infection and dislocation, whereas cemented stems were mostly re-revised later due to aseptic loosening. Interpretation - Both uncemented and cemented revision stems had satisfactory long-term survival but they differed in their modes of failure. Our conclusions are limited by the fact that femoral bone defect size could not be investigated within the setting of the current study.

Background and purpose - Little is known about the role of retained trunnions in revision hip arthroplasties, i.e., when only the femoral head is substituted. Wear (fretting corrosion) and ceramic head fractures are 2 poorly understood concerns related to use, and the role of adapter sleeves has not been defined. In this registry study we assessed the influence of sleeve interposition on re-revision rates in revision hip arthroplasties with retained stems. Confounding factors (demographics, implant-related features) and failures were also analyzed. Patients and methods - We conducted a registry study on 1,127 revised implants (retained trunnion and head exchange). In 26% of implants an adapter sleeve was interposed; in 74% no adapter sleeve was implanted. Demographic and implant-related features were investigated including a descriptive analysis of failures. Results - The mean follow-up of revised implants with and without the use of an adapter sleeve was 3.3 and 5.1 years, respectively. The implant survival without an adapter sleeve was significantly higher, 98.4% (95% CI 96.9-99.8) vs. 95.2% (CI 93.2-96.6) with an adapter sleeve at 5 years. No re-revisions due to adverse local tissue reactions or ceramic head fractures were reported. In order to overcome the different distribution of head materials and head sizes in the two cohorts, only Delta balls were investigated. Interpretation - Adapter sleeve interposition had a minor influence on the revision rates. No adverse local tissue reactions or head fractures occurred.

Background and purpose - To date, there is not a single clinical or mechanical study directly comparing a cemented and a cementless version of the same stem. We investigated the load-to-failure force of a cementless and a cemented version of a double tapered stem. Material and methods - 10 femurs from 5 human cadaveric specimens, mean age 74 years (68-79) were extracted. Bone mineral density (BMD) was measured using peripheral quantitative computed tomography. None of the specimens had a compromised quality (average T value 0.0, -1.0 to 1.4). Each specimen from a pair randomly received a cemented or a cementless version of the same stem. A material testing machine was used for lateral load-to-failure test of up to a maximal load of 5.0 kN. Results - Average load-to-failure of the cemented stem was 2.8 kN (2.3-3.2) and 2.2 kN (1.8-2.8) for the cementless stem (p = 0.002). The cemented version of the stem sustained a higher load than its cementless counterpart in all cases. Failure force was not statistically significantly correlated to BMD (p = 0.07). Interpretation - Implanting a cemented version of the stem increases the load-to-failure force by 25%.

Background: Pelvic discontinuity is a rare condition that is treated with a range of implant constructs. However, surgical failure rates are high, and outcome data are inconsistent. It is therefore difficult to gain a clear picture of whether recently developed constructs (antiprotrusio cage [APC], cup-cage, custom triflange, and porous metal) provide better outcomes in terms of mechanical failure and complications in the short to long terms. This study investigated the failure and complication rates associated with cage constructs and porous metal technologies., Methods: A systematic review and meta-analysis were performed according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines to evaluate the studies showing pelvic discontinuity in revision total hip arthroplasty. Data retrieved included the intervention performed, length of follow-up, mechanical failure, and other complication rates (dislocation, infection, neurological, loosening, migration). Study quality was assessed with the Methodological Index for Non-Randomized Studies (MINORS) instrument. Pooled mechanical failure and complication rates were calculated using MetaXL 5.3., Results: None of the included 30 articles (n = 585 hips) were of high quality. The meta-analyses revealed a mechanical failure rate of 14% for all constructs combined. Custom triflange (5%) and cup-cage (7%) had the lowest mechanical failure rates compared with the commonly used APC (25%) and porous metal (12%). The overall other complication rate was 28%, with cup-cage lower at 21% compared with APC (34%) and custom triflange (28%). Long-term evidence investigating both interventions and porous metal technology is limited., Conclusions: Mechanical failure rates for cup-cage and custom triflange were lowest. The other complication rate for cup-cage was lower than the pooled average. The study quality was limited, indicating a need for better studies and/or a registry., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: The isolated liner and head exchange procedure has been an established treatment method for polyethylene wear and osteolysis when the acetabular component remains well fixed. In this study, the mid-term results of this procedure were evaluated retrospectively., Methods: Among the consecutive patients operated on from September 1995, two patients (three hips) were excluded because of inadequate follow-up, and the results of remaining 34 patients (34 hips) were evaluated. There were 20 men and 14 women with a mean age of 49 years. A conventional polyethylene liner was used in 26 cases and a highly cross-linked polyethylene liner was used in eight cases. In three cases, the liner was cemented in a metal shell because a compatible liner could not be used., Results: After a follow-up of 5 to 20.2 years, re-revision surgery was necessary in 10 cases (29.4%): in eight for wear and osteolysis at 55 to 101 months after liner exchange and in two for acetabular loosening at 1 and 1.5 years after liner exchange. Re-revision surgery included all component revision (four cases), cup revision (four cases), and liner exchange (two cases). In all re-revision cases, a conventional polyethylene liner was used initially. There was no failure in the cases in which a highly cross-linked polyethylene liner was used., Conclusions: The results of this study suggest that isolated acetabular liner exchange is a reasonable option for wear and osteolysis when the metal shell is well fixed. More promising long-term results are expected with the use of highly cross-linked polyethylene liners., Competing Interests: CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported.

Aims: The aim of this study was to give estimates of the incidence of component incompatibility in hip and knee arthroplasty and to test the effect of an online, real-time compatibility check., Materials and Methods: Intraoperative barcode registration of arthroplasty implants was introduced in Denmark in 2013. We developed a compatibility database and, from May 2017, real-time compatibility checking was implemented and became part of the registration. We defined four classes of component incompatibility: A-I, A-II, B-I, and B-II, depending on an assessment of the level of risk to the patient (A/B), and on whether incompatibility was knowingly accepted (I/II)., Results: A total of 26 524 arthroplasties were analyzed. From 12 307 procedures that were undertaken before implementation of the compatibility check, 21 class A incompatibilities were identified (real- or high-risk combinations; 0.17%; 95% confidence interval (CI) 0.11 to 0.26). From 5692 hip and 6615 knee procedures prior to implementation of the compatibility check, we found rates of class A-I incompatibility (real- or high-risk combinations unknowingly inserted) of 0.14% (95% CI 0.06 to 0.28) and 0.17% (95% CI 0.08 to 0.30), respectively. From 14 217 procedures after the introduction of compatibility checking (7187 hips and 7030 knees), eight class A incompatibilities (0.06%; 95% CI 0.02 to 0.11) were identified. This difference was statistically significant (p = 0.008)., Conclusion: Our data presents validated estimates of the baseline incidence of incompatibility events for hip and knee arthroplasty procedures and shows that a significant reduction in class A incompatibility events is possible using a web-based recording system. Cite this article: Bone Joint J 2019;101-B:960-969.

Introduction: The ideal method and implant to perform total hip arthroplasty (THA) is still a debated topic. Ceramic on ceramic (CoC) bearings have favourable wear properties, but squeaking has been reported as an unwanted side effect. We aimed to determine the rate of noise generation from CoC hips and investigate whether there is a relationship with patient satisfaction., Methods: A total of 246 consecutive CoC bearing uncemented THA were retrospectively identified in a single institution. Post-operatively patients were sent a postal questionnaire to evaluate their reported sounds and satisfaction with their THA. Uni- and multi-variate analyses were performed to identify potential predictor variables for reported post-operative sounds., Results: Questionnaires were returned by 172 patients (70% return rate). 24% reported sounds from their hips with 11% reporting a squeak. Median satisfaction levels were minimally, but significantly less for "noisy" (9/10) than "quiet" hips (10/10) (median difference = - 1, 95% CI - 2 to 0, p < 0.001). Compared to those with "noisy" hips, patients with "quiet" hips were 1.7 times (95% CI 1.3-2.5, p = 0.0002) more likely to report a "forgotten" hip. Younger age (p < 0.043) and increased anteversion (p < 0.021) were predictors for reported sounds., Conclusion: We have identified a high rate of "noisy" hips in this series of CoC THA with a significant inverse relationship between "noisy" hips and patient satisfaction levels. In our unit, we are moving towards the use of ceramic on cross-linked polyethylene bearings as a result of these findings and the excellent survivorship of this bearing combination.

Ceramic bearings have several desirable properties, such as resistance to wear, hardness, and biocompatibility, that favour it as an articulating surface in hip arthroplasty. However, ceramic fracture remains a concern. We have reviewed the contemporary literature, addressing the factors that can influence the incidence of ceramic bearing surface fracture. Cite this article: Bone Joint J 2019;101-B:897-901.

Background: The aim of this study is to determine the influence of crosslinking and addition of 0.3 wt% vitamin E in a polyethylene rim on its mechanical damage and oxidation caused by impingement., Methods: Six ultrahigh-molecular weight polyethylene samples were studied (control; crosslinked; vitamin-E containing; crosslinked and vitamin-E containing; aged control; and aged crosslinked and vitamin-E containing). Crosslinking was attained by irradiation with a 300 kGy electron beam; vitamin E incorporation was at 0.3 wt%; and aging was performed through forced oxidation for 14 days. Resistance to impingement was evaluated by stereoscopic observations, three-dimensional measurements, and oxidation measurements by Fourier transform infrared spectroscopy., Findings: Rim breakage (delamination and fracture) due to impingement was observed only for the aged control specimen. In contrast, crosslinked specimens containing vitamin E showed no failure of the rim after aging. The addition of vitamin E to polyethylene suppressed its oxidation and reduced the oxidation caused by crosslinking or impingement. The impingement resistance of the control sample deteriorated upon oxidation, whereas that of vitamin E-containing crosslinked polyethylene remained high due to the antioxidant property of vitamin E., Interpretation: Vitamin E-containing polyethylene showed a reduced risk of wear/breakage of polyethylene rims by impingement., (Copyright © 2019 Elsevier Ltd. All rights reserved.)