Total hip replacement is a common and highly effective operation. All hip replacements would eventually fail if in situ long enough and it is important that patients understand when this might happen. We aimed to answer the question: how long does a hip replacement last? We did a systematic review and meta-analysis with a search of MEDLINE and Embase from the start of records to Sept 12, 2017. We included articles reporting 15-year survival of primary, conventional total hip replacement constructs in patients with osteoarthritis. We extracted survival and implant data and used all-cause construct survival as the primary outcome. We also reviewed reports of national joint replacement registries, and extracted data for a separate analysis. In the meta-analyses, we weighted each series and calculated a pooled survival estimate for each source of data. This study was registered with PROSPERO (CRD42018085642). We identified 140 eligible articles reporting 150 series, and included 44 of these series (13 212 total hip placements). National joint replacement registries from Australia and Finland provided data for 92 series (215 676 total hip replacements). The 25-year pooled survival of hip replacements from case series was 77·6% (95% CI 76·0-79·2) and from joint replacement registries was 57·9% (95% CI 57·1-58·7). Assuming that estimates from national registries are less likely to be biased, patients and surgeons can expect a hip replacement to last 25 years in around 58% of patients. National Institute for Health Research, National Joint Registry for England, Wales, Northern Ireland and Isle of Man, and The Royal College of Surgeons of England.

Periprosthetic joint infection (PJI) is a serious complication of total knee arthroplasty. Two-stage revision is the most widely used technique and considered as the most effective for treating periprosthetic knee infection. The one-stage revision strategy is an emerging alternative option, however, its performance in comparison to the two-stage strategy is unclear. We therefore sought to ask if there was a difference in re-infection rates and other clinical outcomes when comparing the one-stage to the two-stage revision strategy. Our first objective was to compare re-infection (new and recurrent infections) rates for one- and two-stage revision surgery for periprosthetic knee infection. Our second objective was to compare between the two revision strategies, clinical outcomes as measured by postoperative Knee Society Knee score, Knee Society Function score, Hospital for Special Surgery knee score, WOMAC score, and range of motion. Systematic review and meta-analysis. MEDLINE, EMBASE, Web of Science, Cochrane Library, reference lists of relevant studies to August 2015, and correspondence with investigators. Longitudinal (prospective or retrospective cohort) studies conducted in generally unselected patients with periprosthetic knee infection treated exclusively by one- or two-stage revision and with re-infection outcomes reported within two years of revision surgery. No clinical trials comparing both revision strategies were identified. Two independent investigators extracted data and discrepancies were resolved by consensus with a third investigator. Re-infection rates from 10 one-stage studies (423 participants) and 108 two-stage studies (5,129 participants) were meta-analysed using random-effect models after arcsine transformation. The rate (95% confidence intervals) of re-infection was 7.6% (3.4–13.1) in one-stage studies. The corresponding re-infection rate for two-stage revision was 8.8% (7.2–10.6). In subgroup analyses, re-infection rates remained generally similar for several study-level and clinically relevant characteristics. Postoperative clinical outcomes of knee scores and range of motion were similar for both revision strategies. Potential bias owing to the limited number of one-stage revision studies and inability to explore heterogeneity in greater detail. Available evidence from aggregate published data suggest the one-stage revision strategy may be as effective as the two-stage revision strategy in treating infected knee prostheses in generally unselected patients. Further investigation is warranted. PROSPERO 2015: CRD42015017327

Total hip replacement (THR) and total knee replacement (TKR) are common and effective interventions for degenerative joint conditions, such as osteoarthritis.¹ Venous thromboembolism (VTE) (deep vein thrombosis [DVT] and pulmonary embolism [PE]) is an important cause of long-term morbidity, represents a preventable cause of mortality, and has substantial health care costs.² All patients undergoing joint replacement are at risk of VTE because of the duration of surgery and reduced perioperative mobility. To reduce VTE risk, almost all patients receive up to 35 days of anticoagulation after surgery.³ Rates of VTE at 90 days after THR and TKR are variable (up to 5% for DVT and up to 2% for PE in anticoagulated patients).⁴

Prosthetic joint infection is a devastating complication of knee replacement. The risk of developing a prosthetic joint infection is affected by patient, surgical, and health-care system factors. Existing evidence is limited by heterogeneity in populations studied, short follow-up, inadequate power, and does not differentiate early prosthetic joint infection, most likely related to the intervention, from late infection, more likely to occur due to haematogenous bacterial spread. We aimed to assess the overall and time-specific associations of these factors with the risk of revision due to prosthetic joint infection following primary knee replacement. In this cohort study, we analysed primary knee replacements done between 2003 and 2013 in England and Wales and the procedures subsequently revised for prosthetic joint infection between 2003 and 2014. Data were obtained from the National Joint Registry linked to the Hospital Episode Statistics data in England and the Patient Episode Database for Wales. Each primary replacement was followed for a minimum of 12 months until the end of the observation period (Dec 31, 2014) or until the date of revision for prosthetic joint infection, revision for another indication, or death (whichever occurred first). We analysed the data using Poisson and piecewise exponential multilevel models to assess the associations between patient, surgical, and health-care system factors and risk of revision for prosthetic joint infection. Of 679 010 primary knee replacements done between 2003 and 2013 in England and Wales, 3659 were subsequently revised for an indication of prosthetic joint infection between 2003 and 2014, after a median follow-up of 4·6 years (IQR 2·6-6·9). Male sex (rate ratio [RR] for male vs female patients 1·8 [95% CI 1·7-2·0]), younger age (RR for age ≥80 years vs <60 years 0·5 [0·4-0·6]), higher American Society of Anaesthesiologists [ASA] grade (RR for ASA grade 3-5 vs 1, 1·8 [1·6-2·1]), elevated body-mass index (BMI; RR for BMI ≥30 kg/m2vs <25 kg/m2 1·5 [1·3-1·6]), chronic pulmonary disease (RR 1·2 [1·1-1·3]), diabetes (RR 1·4 [1·2-1·5]), liver disease (RR 2·2 [1·6-2·9]), connective tissue and rheumatic diseases (RR 1·5 [1·3-1·7]), peripheral vascular disease (RR 1·4 [1·1-1·7]), surgery for trauma (RR 1·9 [1·4-2·6]), previous septic arthritis (RR 4·9 [2·7-7·6]) or inflammatory arthropathy (RR 1·4 [1·2-1·7]), operation under general anaesthesia (RR 1·1 [1·0-1·2]), requirement for tibial bone graft (RR 2·0 [1·3-2·7]), use of posterior stabilised fixed bearing prostheses (RR for posterior stabilised fixed bearing prostheses vs unconstrained fixed bearing prostheses 1·4 [1·3-1·5]) or constrained condylar prostheses (3·5 [2·5-4·7]) were associated with a higher risk of revision for prosthetic joint infection. However, uncemented total, patellofemoral, or unicondylar knee replacement (RR for uncemented vs cemented total knee replacement 0·7 [95% CI 0·6-0·8], RR for patellofemoral vs cemented total knee replacement 0·3 [0·2-0·5], and RR for unicondylar vs cemented total knee replacement 0·5 [0·5-0·6]) were associated with lower risk of revision for prosthetic joint infection. Most of these factors had time-specific effects, depending on the time period post-surgery. We have identified several risk factors for revision for prosthetic joint infection following knee replacement. Some of these factors are modifiable, and the use of targeted interventions or strategies could lead to a reduced risk of revision for prosthetic joint infection. Non-modifiable factors and the time-specific nature of the effects we have observed will allow clinicians to appropriately counsel patients preoperatively and tailor follow-up regimens. National Institute for Health Research.

The risk of prosthetic joint infection (PJI) is influenced by patient, surgical, and health-care factors. Existing evidence is based on short-term follow-up. It does not differentiate between factors associated with early onset caused by the primary intervention from those associated with later onset more likely to result from haematogenous spread. We aimed to assess the overall and time-specific associations of these factors with the risk of revision due to PJI after primary total hip replacement. We did a prospective observational cohort study analysing 623 253 primary hip procedures performed between April 1, 2003, and Dec 31, 2013, in England and Wales and recorded the number of procedures revised because of PJI. We investigated the associations between risk factors and risk of revision for PJI across the overall follow-up period using Poisson multilevel models. We reinvestigated the associations by post-operative time periods (0-3 months, 3-6 months, 6-12 months, 12-24 months, >24 months) using piece-wise exponential multilevel models with period-specific effects. Data were obtained from the National Joint Registry linked to the Hospital Episode Statistics data. 2705 primary procedures were subsequently revised for an indication of PJI between 2003 and 2014, after a median (IQR) follow up of 4·6 years (2·6-7·0). Among the factors associated with an increased revision due to PJI there were male sex (1462 [1·2‰] of 1 237 170 male-years vs 1243 [0·7‰] of 1 849 691 female-years; rate ratio [RR] 1·7 [95% CI 1·6-1·8]), younger age (739 [1·1‰] of 688 000 person-years <60 years vs 242 [0·6‰] of 387 049 person-years ≥80 years; 0·7 [0·6-0·8]), elevated body-mass index (BMI; 941 [1·8‰] 517 278 person-years with a BMI ≥30 kg/m2vs 272 [0·9‰] of 297 686 person-years with a BMI <25 kg/m2; 1·9 [1·7-2·2]), diabetes (245 [1·4‰] 178 381 person-years with diabetes vs 2120 [1·0‰] of 2 209 507 person-years without diabetes; 1·4 [1·2-1·5]), dementia (5 [10·1‰] of 497 person-years with dementia at 3 months vs 311 [2·6‰] of 120 850 person-years without dementia; 3·8 [1·2-7·8]), previous septic arthritis (22 [7·2‰] of 3055 person-years with previous infection vs 2683 [0·9‰] of 3 083 806 person-years without previous infection; 6·7 [4·2-9·8]), fractured neck of femur (66 [1·5‰] of 43 378 person-years operated for a fractured neck of femur vs 2639 [0·9‰] of 3 043 483 person-years without a fractured neck of femur; 1·8 [1·4-2·3]); and use of the lateral surgical approach (1334 [1·0‰] of 1 399 287 person-years for lateral vs 1242 [0·8 ‰] of 1 565 913 person-years for posterior; 1·3 [1·2-1·4]). Use of ceramic rather than metal bearings was associated with a decreased risk of revision for PJI (94 [0·4‰] of 239 512 person-years with ceramic-on-ceramic bearings vs 602 [0·5‰] of 1 114 239 peron-years with metal-on-polyethylene bearings at ≥24 months; RR 0·6 [0·4-0·7]; and 82 [0·4‰] of 190 884 person-years with ceramic-on-polyethyene bearings vs metal-on-polyethylene bearings at ≥24 months; 0·7 [0·5-0·9]). Most of these factors had time-specific effects. The risk of revision for PJI was marginally or not influenced by the grade of the operating surgeon, the absence of a consultant surgeon during surgey, and the volume of procedures performed by hospital or surgeon. Several modifiable and non-modifiable factors are associated with the risk of revision for PJI after primary hip replacement. Identification of modifiable factors, use of targeted interventions, and beneficial modulation of some of these factors could be effective in reducing the incidence of PJI. It is important for clinicians to consider non-modifiable factors and factors that exhibit time-specific effects on the risk of PJI to counsel patients appropriately preoperatively. National Institute for Health Research.

Dislocation following total hip replacement (THR) is associated with repeated hospitalisations and substantial costs to the health system. Factors influencing dislocation following primary THR are not well understood. We aimed to assess the associations of patient-, surgery-, implant- and hospital-related factors with dislocation risk following primary THR. We did a systematic review and meta-analysis of all longitudinal studies reporting these associations. We searched MEDLINE, Embase, Web of Science, and Cochrane Library to March 8, 2019. Summary measures of association were calculated using relative risks (RRs) (with 95% confidence intervals, CIs). The review is registered on PROSPERO, number CRD42019121378. We identified 149 articles based on 125 unique studies with data on 4 633 935 primary THRs and 35 264 dislocations. The incidence rates of dislocation ranged from 0·12% to 16·13%, with an overall pooled rate of 2·10% (1·83-2·38) over a weighted mean follow-up duration of 6 years. Using median year of data collection, there was a significant decline in dislocation rates from 1971 to 2015. Comparing males vs females, age ≥70 vs <70 years, and high vs low income, RRs (95% CIs) for dislocation were 0·97 (0·88-1·08), 1·27 (1·02-1·57), and 0·79 (0·74-0·85) respectively. White ethnicity, drug use disorder, and social deprivation were each associated with an increased dislocation risk. Comparing body mass index (BMI) ≥30 vs. <30 kg/m², the RR (95% CI) for dislocation was 1·38 (1·03-1·85). Medical and surgical history-related factors associated with dislocation risk included neurological disorder, psychiatric disease, comorbidity indices, previous surgery including spinal fusion, and surgical indications including avascular necrosis, rheumatoid arthritis, inflammatory arthritis, and osteonecrosis. Surgical factors such as the anterolateral, direct anterior, or lateral approach and posterior with short external rotator and capsule repair were each associated with reduced dislocation risk. At the implant level, larger femoral head diameters, elevated acetabular liners, dual mobility cups, cemented fixations and standard femoral neck lengths reduced the risk of dislocation. Hospital-related factors such as experienced surgeons and high surgeon procedure volume each reduced the risk of dislocation. Dislocation following primary THR is on a temporal decline. Surgical approaches that reduce dislocation risk can be used by clinicians when performing primary THR. Alternative bearings such as dual mobility can be used in individuals at high risk of dislocation. Modifiable risk factors such as high BMI and comorbidities may be amenable to optimisation prior to surgery. National Institute for Health Research