How to manage treatment failure in prosthetic joint infection.

BACKGROUND: Management for prosthetic joint infections remains a challenging area for both infectious diseases and orthopaedic surgery, particularly in the setting of treatment failure. This is compounded by a lack of level 1 evidence to guide approaches. The optimal management of prosthetic joint infections requires a multi-disciplinary approach combined with shared decision making with the patient. AIMS: This article describes the approach to prosthetic joint infections in the setting of treatment failure. SOURCES: Narrative review based on literature review from PubMed. There was no time limit on the studies included. In addition, the reference list for included studies were reviewed for literature saturation with manual searching of clinical guidelines. Management approaches described incorporate evidence- and eminence-based recommendations from expert guidelines and clinical studies, where applicable. CONTENT: The surgical and antimicrobial approaches for prosthetic joint infections are described for first-line treatment of prosthetic joint infections and approaches in the event of treatment failure. Management approaches are based on an understanding of the role the biofilm plays in the pathogenesis of prosthetic joint infections. The management of these infections aims to fulfil two key goals: to eradicate the biofilm-associated microorganisms and, to maintain a functional joint and quality of life. In treatment failure, these goals are not always feasible, and the role of the multi-disciplinary team and shared-decision making are prominent. IMPLICATIONS: Prosthetic joint surgery is a high-volume surgery, and the demand for this surgery is continually increasing. With this, the number of infections requiring expert care will also increase. Eminence-based management approaches have been established to guide treatment failure until knowledge gaps in optimal management are addressed by well-designed, clinical trials.

What Is the Risk of THA Revision for ARMD in Patients with Non-metal-on-metal Bearings? A Study from the Australian National Joint Replacement Registry.

BACKGROUND: There are increasing reports of corrosion between the femoral head and trunnion in primary conventional THA, resulting in metal particulate release often termed trunnionosis. There may be heightened awareness of this condition because of severe soft-tissue reactions initially thought to be solely attributable to prostheses with a metal-on-metal (MoM) bearing surface. It is unclear what percentage of revisions for THA with non-MoM bearing surfaces can be attributed to trunnionosis and to what extent adverse reaction to metal debris (ARMD) seen with MoM bearings may also be seen with other bearing surfaces in THA. QUESTIONS/PURPOSES: We analyzed data from a large national registry to ask: (1) What is the revision risk for the indication of ARMD in patients with conventional THA and modern non-MoM bearing surfaces such as metal or ceramic-on-cross-linked polyethylene (XLPE) or ceramic-on-ceramic? (2) What prosthesis factors are associated with an increased risk of such revision? (3) What is the relative revision risk for ARMD in THAs with large-head MoM bearings, small-head MoM bearings, and non-MoM modern bearing surfaces? METHODS: The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) longitudinally maintains data on all primary and revision joint arthroplasties, with nearly 100% capture. The study population included all THAs using modern bearing surfaces (defined as metal or ceramic heads-on-XLPE and ceramic-on-ceramic bearing couples) revised because of ARMD between September 1999 and December 2018. Prostheses with modular necks were excluded. The cumulative percent revision (CPR) because of ARMD was determined. The study group consisted of 350,027 THAs with a modern bearing surface, 15,184 THAs with a large-head MoM bearing (≥ 36 mm), and 5474 THAs with a small head MoM bearing (≤ 32 mm). The patients in the group who received the modern bearing surfaces were slightly older than the patients in the groups who received the large- and small-head bearing surfaces, with a mean age 68 years (SD 12) versus a mean age 63 years (SD 12), and a mean age 62 years (SD 11), respectively. There was a higher proportion of women in the modern bearing surface group; 55% (193,312 of 350,027), compared with 43% (6497 of 15,184) in the large-head MoM group and 50% (2716 of 5474) in the small-head MoM group. The outcome measure was the CPR, which was defined using Kaplan-Meier estimates of survivorship to describe the time to the first revision for ARMD at 17 years. Hazard ratios (HR) from Cox proportional hazards models, adjusting for age and sex, were performed to compare the revision rates among groups. The registry defines a revision as a reoperation of a previous hip arthroplasty in which one or more of the prosthetic components is replaced or removed, or one or more components is added. RESULTS: The CPR for ARMD for patients with a modern bearing surface at 17 years was 0.1% (95% confidence interval 0.0 to 0.1). After controlling for age and sex, we found that cobalt chrome heads, two specific prostheses (Accolade® I and M/L Taper), and head sizes ≥ 36 mm were associated with an increased risk of revision for ARMD. Metal-on-XLPE had a higher risk of revision for ARMD than ceramic-on-ceramic or ceramic-on-XLPE (HR 3.4 [95% CI 1.9 to 6.0]; p < 0.001). The Accolade 1 and the M/L Taper stems had a higher risk of revision than all other stems (HR, 8.3 [95% CI 4.7 to 14.7]; p < 0.001 and HR 14.4 [95% CI 6.0 to 34.6]; p < 0.001, respectively). Femoral stems with head sizes ≥ 36 mm had a higher rate of revision for ARMD than stems with head sizes ≤ 32 mm (HR 3.2 [95% CI 1.9 to 5.3]; p < 0.001).Large-head MoM bearings had a greater increase in revision for ARMD compared with modern bearing surfaces. The CPR for patients with a large-head MoM bearing at 17 years for ARMD was 15.5% (95% CI 14.5 to 16.6) and it was 0.1% for modern bearing surfaces (HR 340 [95% CI 264.2 to 438.0]; p < 0.001). Modern bearing surfaces likewise had a lower HR for revision for ARMD than did THAs with small-head MoM bearings, which had a 0.9% (95% CI 0.7 to 1.4) CPR compared with modern bearings from 0 to 9 years (HR 10.5 [95% CI 6.2 to 17.7]; p < 0.001). CONCLUSIONS: The revision risk for ARMD with modern bearing surfaces in THA is low. The Accolade 1 and the M/L Taper stem have a higher risk of revision for ARMD and cobalt-chrome heads, and head sizes ≥ 36 mm have a higher rate of revision than ≤ 32 mm head sizes. ARMD is a rare failure mode for THA with non-MoM bearings, but in patients presenting with unexplained pain with no other obvious cause, this diagnosis should be considered and investigated further. LEVEL OF EVIDENCE: Level III, therapeutic study.

Greater risks of complications, infections, and revisions in the obese versus non-obese total hip arthroplasty population of 2,190,824 patients: a meta-analysis and systematic review.

BACKGROUND: Obesity is an epidemic, especially in developed countries. This affects the general health of these patients, especially when they are having a major surgical procedure such as total hip arthroplasty (THA). Several articles have described the effects of obesity on THA with varying conclusions. This meta-analysis aims to compare the outcomes, complications, and peri-operative parameters of THA in the obese (BMI≥30 kg/m2) vs non-obese (BMI<30 kg/m2) population as well as a subgroup analysis of morbidly obese (BMI≥40 kg/m2) vs non-obese population. METHODS: A multi-database search was performed according to PRISMA guidelines. Data from studies assessing the outcomes and complications of THA in the obese and non-obese population were extracted and analyzed. RESULTS: Sixty-seven studies were included in this meta-analysis, consisting of 581,012 obese and 1,609,812 non-obese patients. Meta-analysis could not be performed on patient reported outcome measures due to heterogeneous reporting methods. Obese patients had a higher risk of all complications (OR = 1.53, 95%CI: 1.30-1.80, P < 0.001), deep infections (OR = 2.71, 95%CI: 2.08-3.53, P < 0.001), superficial infections (OR = 1.99, 95%CI: 1.55-2.55, P < 0.001), dislocations (OR = 1.72, 95%CI: 1.66-1.79, P < 0.001), reoperations (OR = 1.61, 95%CI: 1.40-1.85, P < 0.001), revisions (OR = 1.44, 95%CI: 1.32-1.57, P < 0.001), and readmissions (OR = 1.37, 95%CI: 1.15-1.63, P < 0.001). When sub-group analysis of morbidly obese (BMI≥40 kg/m2) patients was performed, the risks of all these parameters were even greater. CONCLUSION: Obese and morbidly obese patients are at higher risks of complications post THA than non-obese patients. Surgeons should be aware of these risks in order to counsel patients and adopt prophylactic strategies to reduce these risks where applicable.

Practice variation in total hip arthroplasty versus hemiarthroplasty for treatment of fractured neck of femur in Australia.

AIMS: Displaced femoral neck fractures (FNF) may be treated with partial (hemiarthroplasty, HA) or total hip arthroplasty (THA), with recent recommendations advising that THA be used in community-ambulant patients. This study aims to determine the association between the proportion of FNF treated with THA and year of surgery, day of the week, surgeon practice, and private versus public hospitals, adjusting for known confounders. PATIENTS AND METHODS: Data from 67 620 patients in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 1999 to 2016 inclusive were used to generate unadjusted and adjusted analyses of the associations between patient, time, surgeon and institution factors, and the proportion of FNF treated with THA. RESULTS: Overall, THA was used in 23.7% of patients. THA was more frequently used over time, in younger patients, in healthier patients, in cases performed on weekdays (adjusted odds ratio (OR) 1.27; 95% confidence interval (CI) 1.14 to 1.41), in private hospitals (adjusted OR 4.34; 95% CI 3.94 to 4.79) and by surgeons whose hip arthroplasty practice has a relatively higher proportion of elective patients (adjusted OR 1.65; 95% CI 1.49 to 1.83). CONCLUSION: Practice variation exists in the proportion of FNF patients treated with THA due to variables other than patient factors. This may reflect variation in resources available and surgeon preference, and uncertainty regarding the relative indication.

Cross-Linked Polyethylene for Total Hip Arthroplasty Markedly Reduces Revision Surgery at 16 Years.

BACKGROUND: Total hip arthroplasty (THA) is an effective operation for the management of end-stage hip osteoarthritis, but long-term success can be limited by wear of the polyethylene bearing surface. Cross-linking conventional polyethylene has resulted in lower wear rates and a reduction in bone lysis in both laboratory and clinical studies. The aim of this study was to compare the rates of revision between cross-linked polyethylene (XLPE) and conventional non-cross-linked polyethylene (CPE) at 16 years after THAs performed for the treatment of osteoarthritis. METHODS: We performed an observational study of data, from a national registry, on all patients who underwent THA for osteoarthritis in Australia from 1999 through December 31, 2016. The outcomes of THAs performed with CPE were compared with those of THAs performed with XLPE, along with an analysis of the effect of age, sex, femoral head size, the method of acetabular and femoral component fixation, and the reasons and types of revision. The principal outcome measure was the time to the first revision, determined using Kaplan-Meier estimates of survivorship. RESULTS: CPE was used in 41,171 procedures, and XLPE was used in 199,131. The mean ages of the men and women treated with CPE were 70.0 years (standard deviation [SD] = 9.9 years) and 72.5 years (SD = 9.7 years), respectively, whereas the men and women who received XLPE were slightly younger (mean age, 68.6 years [SD = 10.3 years] and 70.7 years [SD = 9.9 years], respectively. XLPE was associated with a lower rate of revision than CPE at 6 months, and this difference became more apparent with time. The 16-year cumulative percentage of revisions of the primary THAs was 11.7% (95% confidence interval [CI] = 11.1% to 12.3%]) in the CPE group and 6.2% (95% CI = 5.7% to 6.7%) in the XLPE group. The hazard ratio at 9 years was 3.02 (p = 0.001). CONCLUSIONS: The use of XLPE has resulted in a significant reduction in the rate of revision at 16 years following THA for osteoarthritis. This evidence suggests that the longevity of THA is likely to be improved, which may enable younger patients to undergo surgery, confident of a reduced need for revision in the long term. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The use of femoral stems with exchangeable necks in primary total hip arthroplasty increases the rate of revision.

AIMS: Femoral stems with exchangeable (modular) necks were introduced to offer surgeons an increased choice when determining the version, offset and length of the femoral neck during total hip arthroplasty (THA). It was hoped that this would improve outcomes and reduce complications, particularly dislocation. In 2010, the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) first reported an increased rate of revision after primary THA using femoral stems with an exchangeable neck. The aim of this study was to provide a more comprehensive up-to-date analysis of primary THA using femoral stems with exchangeable and fixed necks. MATERIALS AND METHODS: The data included all primary THA procedures performed for osteoarthritis (OA), reported to the AOANJRR between 01 September 1999 and 31 December 2014. There were 9289 femoral stems with an exchangeable neck and 253 165 femoral stems with a fixed neck. The characteristics of the patients and prostheses including the bearing surface and stem/neck metal combinations were examined using Cox proportional hazard ratios (HRs) and Kaplan-Meier estimates of survivorship. RESULTS: It was found that prostheses with an exchangeable neck had a higher rate of revision and this was evident regardless of the bearing surface or the size of the femoral head. Exchangeable neck prostheses with a titanium stem and a cobalt-chromium neck had a significantly higher rate of revision compared with titanium stem/titanium neck combinations (HR 1.83, 95% confidence interval 1.49 to 2.23, p < 0.001). Revisions were higher for these combinations compared with femoral stems with a fixed neck. CONCLUSION: There appears to be little evidence to support the continued use of prostheses with an exchangeable neck in primary THA undertaken for OA. Cite this article: Bone Joint J 2017;99-B:766-73.

Substantial rise in the lifetime risk of primary total knee replacement surgery for osteoarthritis from 2003 to 2013: an international, population-level analysis.

OBJECTIVE: To estimate and compare the lifetime risk of total knee replacement surgery (TKR) for osteoarthritis (OA) between countries, and over time. METHOD: Data on primary TKR procedures performed for OA in 2003 and 2013 were extracted from national arthroplasty registries in Australia, Denmark, Finland, Norway and Sweden. Life tables and population data were also obtained for each country. Lifetime risk of TKR was calculated for 2003 and 2013 using registry, life table and population data. RESULTS: Marked international variation in lifetime risk of TKR was evident, with females consistently demonstrating the greatest risk. In 2013, Finland had the highest lifetime risk for females (22.8%, 95%CI 22.5-23.1%) and Australia had the highest risk for males (15.4%, 95%CI 15.1-15.6%). Norway had the lowest lifetime risk for females (9.7%, 95%CI 9.5-9.9%) and males (5.8%, 95%CI 5.6-5.9%) in 2013. All countries showed a significant rise in lifetime risk of TKR for both sexes over the 10-year study period, with the largest increases observed in Australia (females: from 13.6% to 21.1%; males: from 9.8% to 15.4%). CONCLUSIONS: Using population-based data, this study identified significant increases in the lifetime risk of TKR in all five countries from 2003 to 2013. Lifetime risk of TKR was as high as 1 in 5 women in Finland, and 1 in 7 males in Australia. These risk estimates quantify the healthcare resource burden of knee OA at the population level, providing an important resource for public health policy development and healthcare planning.

Twelve-month mortality and functional outcomes in hip fracture patients under 65 years of age.

INTRODUCTION: There has been a recent call for improved functional outcome reporting in younger hip fracture patients. Younger hip fracture patients represent a different population with different functional goals to their older counterparts. Therefore, previous research on mortality and functional outcomes in hip fracture patients may not be generalisable to the younger population. The aims of this study were to report 12-month survival and functional outcomes in hip fracture patients aged <65 years and predictors of functional outcome. METHODS: Hip fracture patients aged <65years (range 17-64) registered by the Victorian Orthopaedic Trauma Outcomes Registry over four years were included and their 12-month survival and functional outcomes (Extended Glasgow Outcome Scale) reported. Ordered multivariable logistic regression was used to identify predictors of higher function. RESULTS: There were 507 patients enrolled in the study and of the 447 patients (88%) with 12-month outcomes, 24 (5%) had died. The majority of patients had no comorbidities or pre-injury disability and were injured via road trauma or low falls. 40% of patients sustained additional injuries to their hip fracture. 23% of patients had fully recovered at 12 months and 39% reported ongoing moderate disability. After adjusting for all key variables, odds of better function 12-months post-fracture were reduced for patients with co-morbidities, previous disability or additional injuries, those receiving compensation or injured via low falls. CONCLUSIONS: While 12-month survival rates were satisfactory in hip fracture patients aged under 65 years, their functional outcomes were poor, with less than one quarter having fully recovered 12 months following injury. This study provides new information about which patients may have difficulty returning to their pre-injury level of function. These patients may require additional or more intensive post-discharge care in order to fulfil their functional goals and continue to contribute productively to society.

Geographical variation in incidence of knee arthroscopy for patients with osteoarthritis: a population-based analysis of Victorian hospital separations data.

BACKGROUND/AIM: To evaluate the frequency and geographical variation in knee arthroscopy for adults (>25 years) with a concomitant diagnosis of osteoarthritis. METHODS: This was a retrospective cohort study of hospital separations involving an elective knee arthroscopy in public and private hospitals in Victoria, Australia. Participants included patients receiving knee arthroscopies with a diagnosis code indicating osteoarthritis (OA) from 1 July 2008 to 30 June 2009. Records were excluded if the patient was under 25 years or their arthroscopy involved a ligament reconstruction. Crude rates per 100 000 population and negative binomial regression offset by total knee arthroscopy volume were used to analyse differences by region. RESULTS: There were 9620 arthroscopic procedures meeting the inclusion criteria. There were 5500 (57.2%) admissions where the principal diagnosis was knee OA (gonarthrosis) and 3510 (36.5%) where the principal diagnosis indicated a mechanical derangement and there was a primary or associated diagnosis of OA. When we examined the incidence rate ratios (IRR) by region, after adjustment for relevant factors and accounting for the total knee arthroscopy volume within each region, we identified significant variation in knee arthroscopy rates for patients with OA. The region with the highest adjusted IRR was Barwon South Western (IRR: 1.26, 95% confidence interval (CI): 1.16-1.36) and the region with lowest adjusted incidence rate ratio was the Gippsland region (IRR: 0.89, 95% CI: 0.80-0.98). CONCLUSIONS: We identified considerable geographical variation in arthroscopies for people with OA across Victoria. Further investigation is needed to understand whether this variation is a reflection of differences in OA prevalence, clinical decision-making or access.