The outcomes of conversion of hemiarthroplasty to total hip arthroplasty, a systematic review and meta-analysis.

INTRODUCTION: Acetabular erosion is an important complication in hemiarthroplasty and may lead to total hip arthroplasty as a conversion. The results of total hip arthroplasty as a conversion remain unclear. We performed a systematic review and meta-analysis to compare the outcome of total hip arthroplasty as a conversion with primary total hip arthroplasty. MATERIALS AND METHODS: PRISMA guidelines were used and Pubmed, Embase and the Cochrane libraries were searched. Both, studies comparing the outcome of total hip arthroplasty as a conversion with the outcome of primary total hip arthroplasty and the outcome of cohort studies limited to total hip arthroplasty as a conversion, were included. Risk of bias was assessed using the Methodological Index for Non Randomized Studies checklist. Meta-analysis was performed concerning pooled annual revision, dislocation and infection rates. RESULTS: A total of 27 studies were available for analysis; four comparative studies and 23 cohort studies. Comparative studies were defined as high quality and cohort studies as medium quality. Analysis revealed a significantly higher overall revision risk (Hazard Ratio 1.72, 95% confidence interval 1.39 to 2.14) after total hip arthroplasty as a conversion compared to primary total hip arthroplasty. The annual revision rate of total hip arthroplasty as a conversion was 1.63% (95% confidence interval 1.14 to 2.33) in the comparative studies and 1.40% (95% confidence interval 1.17 to 1.66) in the cohort studies. A pooled infection rate of 4.34% (95% confidence interval 2.66 to 7.01) and dislocation rate of 4.79% (95% confidence interval 3.02 to 7.53), was found. CONCLUSIONS: Literature concerning the results of total hip arthroplasty as a conversion is limited. The risk of revision after conversion of hemiarthroplasty is higher compared to primary total hip arthroplasty.

Revision risk of salvage compared with acute total hip arthroplasty following femoral neck fracture: an analysis from the Dutch Arthroplasty Register.

BACKGROUND AND PURPOSE: There is no consensus on the treatment of patients with femoral neck fractures between internal fixation (IF) or directly treated with a total hip arthroplasty (fracture-THA) in particular for the age group 60-70 years. Failure of IF is not uncommon, resulting in salvage total hip arthroplasty (salvage-THA). The aim of our study was to compare revision rates of salvage-THA with fracture-THA and osteoarthritis (OA)-THA. PATIENTS AND METHODS: Revision rates and reasons for revision were compared. Data collected in the Dutch Arthroplasty Register (LROI) between 2007 and 2018 was used. The study included 4,310 salvage-THAs, 12,159 fracture-THAs, and 274,147 OA-THAs. We performed Kaplan-Meier survival analyses and Cox regression to evaluate THA survival. RESULTS: No statistically significant difference in revision rates between salvage-THAs and fracture-THAs was found (HR 1.0, 95% CI 0.7-1.3) whereas the revision rate was higher compared with OA-THAs (HR 1.3, CI 1.0-1.5). The 5-year revision rate was 5.0% (CI 4.4-5.8) in salvage-THAs, 4.5% (CI 4.1-5.0) in fracture-THAs, and 3.1% (CI 3.0-3.2) in OA-THAs. A higher revision rate for infection was found in salvage-THAs in comparison with fracture-THAs (HR 1.6, CI 1.0-2.3). CONCLUSION: We found no difference in revision rates for salvage-THAs compared with fracture-THAs. The risk of revision for infection was higher for salvage-THA.

Empiric antibiotic therapy in early periprosthetic joint infection: a retrospective cohort study.

PURPOSE: Periprosthetic joint infection (PJI) is a devastating complication following total knee or total hip arthroplasty (TKA/THA). Appropriate empiric antibiotic treatment, initiated directly after debridement and implant retention (DAIR), is suggested to contribute to treatment success. The aim of this study was to describe the microbiology and the antibiotic susceptibility in early PJI to guide future empiric treatment in a region with a low incidence of methicillin-resistant Staphylococcus aureus (MRSA). METHODS: Consecutive patients who underwent DAIR within 3 months after primary unilateral TKA or THA between January 2011 and December 2018 were retrospectively identified from the hospital electronic health records. Data on causative pathogens, antimicrobial susceptibility and the number of post-operative days until cultures demonstrated bacterial growth were collected. RESULTS: One hundred and eleven early PJIs were identified of which 65 (59%) were monomicrobial and 46 (41%) polymicrobial. Among all isolated pathogens, Staphylococcus aureus (n = 53; 29%) was the most commonly identified pathogen in early PJI without any involvement of MRSA. 72% of PJIs were susceptible to vancomycin which could be increased to around 90% by adding gram-negative coverage. On the 5th postoperative day, bacterial growth was observed in 98% of cases. All gram-negative bacteria demonstrated positive tissue cultures on the 4th postoperative day. CONCLUSION: Vancomycin combined with ciprofloxacin or a third generation cephalosporin provided the highest antimicrobial coverage of all responsible pathogens identified in early PJI. Empiric treatment of gram-negative treatment can be safely terminated in the absence of gram-negative pathogens after 4 days of culturing in cases without preoperative antibiotic treatment.

Cost-effectiveness of full endoscopic versus open discectomy for sciatica.

OBJECTIVE: To assess the costs and cost-effectiveness of percutaneous transforaminal endoscopic discectomy (PTED) compared with open microdiscectomy among patients with sciatica. METHODS: This economic evaluation was conducted alongside a 12-month multicentre randomised controlled trial with a non-inferiority design, in which patients were randomised to PTED or open microdiscectomy. Patients were aged from 18 to 70 years and had at least 6 weeks of radiating leg pain caused by lumbar disc herniation. Effect measures included leg pain and quality-adjusted life years (QALYs), as derived using the EQ-5D-5L. Costs were measured from a societal perspective. Missing data were multiply imputed, bootstrapping was used to estimate statistical uncertainty, and various sensitivity analyses were conducted to determine the robustness. RESULTS: Of the 613 patients enrolled, 304 were randomised to PTED and 309 to open microdiscectomy. Statistically significant differences in leg pain and QALYs were found in favour of PTED at 12 months follow-up (leg pain: 6.9; 95% CI 1.3 to 12.6; QALYs: 0.040; 95% CI 0.007 to 0.074). Surgery costs were higher for PTED than for open microdiscectomy (ie, €4500/patient vs €4095/patient). All other disaggregate costs as well as total societal costs were lower for PTED than for open microdiscectomy. Cost-effectiveness acceptability curves indicated that the probability of PTED being less costly and more effective (ie, dominant) compared with open microdiscectomy was 99.4% for leg pain and 99.2% for QALYs. CONCLUSIONS: Our results suggest that PTED is more cost-effective from the societal perspective compared with open microdiscectomy for patients with sciatica. TRIAL REGISTRATION NUMBER: NCT02602093.

Increased failure rates after the introduction of the TFNA proximal femoral nail for trochanteric fractures: implant related or learning curve effect?

Background and purpose - Trochanteric fractures are often treated using intramedullary fixation. In our institution, the TFN-Advanced Proximal Femoral Nailing System (TFNA) was introduced as replacement for the Gamma Trochanteric Nail (GTN3) for the treatment of these fractures as a result of a hospital-driven change of trauma implant supplier. We compared trochanteric fracture fixation failure rate between these 2 intramedullary nails. Patients and methods - All trochanteric fractures treated surgically from 2011 to 2019 were retrospectively reviewed for fixation failure. From 2016 only the TFNA was used. Fixation failure was defined as implant cut-out, implant breakage, non-union, malpositioning of the screw/blade requiring reoperation, new fracture around the nail, or miscellaneous. Propensity score matching was used to balance distribution of covariates and to compare failure rates between TFNA and GTN3 groups. Learning curve analyses were performed. Results - After exclusion, 797 GTN3s (779 patients) and 542 (536 patients) TFNAs were available for analysis. A higher risk of fixation failure was found in the TFNA group (14%) compared with the GTN3 group (7.0%) (hazard ratio [HR] 2.0, 95% confidence interval [CI] 1.2-3.5). This was mainly attributed to a higher risk of cut-out (HR 2.2; CI 0.9-5.7), malpositioning (HR 4.7; CI 0.7-34), and new fracture around the nail (HR 4.0; CI 1.0-16). Learning curve analyses indicated no clear learning curve effect. Interpretation - Failure of fixation increased after a switch from the GTN3 to the TFNA proximal femoral nail for the treatment of trochanteric fractures. Cut-out and malpositioning of the calcar screw or blade appeared to be the most dominant failure mechanisms. Modifications in implant design may have played a role in this increased risk of failure of fixation. In our institution a new implant device was introduced without solid clinical evidence behind it. This study may help to underline the need for medical doctors with a critical and scientific background to be involved in implant choices.

Nonoperative management of hip fractures in very frail elderly patients may lead to a predictable short survival as part of advance care planning.

Background and purpose - Surgical treatment is still the mainstay of care even in very frail elderly hip fracture patients. However, one may argue whether surgery is in the best interest of all patients. We elucidated mortality rates of nonoperative management (NOM) of a hip fracture after shared decision-making in a cohort of very frail elderly patients.Patients and methods - Orthogeriatric patients (age > 70 years) admitted with a hip fracture between 2011 and 2019 were included. In the presence of fragility features the motivation for surgery or NOM was supported by advance care planning (ACP) and shared decision-making through geriatric assessment. Mortality rates after NOM were assessed and also presented for the remaining surgical group for reference.Results - In 1,279 out of 3,467 patients, geriatric assessment was indicated and subsequently 1,188 (93%) had surgery versus 91 (7%) NOM. The motivation for NOM was based on patient and family preferences in only 20% of patients, medical grounds in 54%, and a combination of both in 26%. The 30-day and 1-year mortality in the frail NOM group was 87% and 99% respectively, whereas this was 7% and 28% in the surgery group. No statistical comparison between groups was performed due to profound bias by indication.Interpretation - This study provides further insight into the predictable and high short-term mortality after NOM in carefully selected very frail elderly hip fracture patients. This information may help to consider NOM as an alternative treatment option to surgery when no significant gain from surgery is anticipated.

High incidence of early periprosthetic joint infection following total hip arthroplasty with concomitant or previous hardware removal.

INTRODUCTION: Hardware removal preceding total hip arthroplasty may increase the risk of prosthetic joint infection (PJI). Whether hardware removal and total hip arthroplasty (THA) should be performed in a single- or two-stage procedure remains controversial. In this comparative retrospective study, the incidence of PJI following either single- or two-stage THA with hardware removal was assessed in a consecutive series. PATIENTS AND METHODS: All patients that underwent THA preceded by hardware removal from January 2006 until March 2018 were retrospectively reviewed and checked for the occurrence of early PJI. Recognized risk factors for PJI at the time of surgery were evaluated and the incidence of early PJI was compared between one- and two-stage THA regarding hardware removal. RESULTS: 145 patients underwent THA and hardware removal (52 two-stage surgery and 93 single-stage surgery). There were no significant differences between both groups regarding pre-operative hemoglobulin levels, time interval between internal fixation and THA, antibiotic-loaded-cement use, BMI and ASA classification. Overall the incidence of early PJI was 6.9%. The incidence of PJI was 8.6% in the single-stage group versus 3.8% in the two-stage group (P = 0.234). CONCLUSION: Irrespective of single- or two-stage procedures, a high incidence of PJI was encountered. Despite non-significance, a trend towards a higher proportion of patients developing PJI after single-stage surgery was encountered. We recommend a two-stage surgical procedure regarding hardware removal and THA in patients that are expected to tolerate this surgical strategy. When considering a one-stage procedure, it should be preceded by a thorough pre-operative workup including joint aspiration and serum determination of inflammatory parameters. Multiple tissue samples should be obtained during hardware removal in either one- or two-stage procedures since the risk for development of PJI is relevant.

General anesthesia might be associated with early periprosthetic joint infection: an observational study of 3,909 arthroplasties.

Background and purpose - Periprosthetic joint infection (PJI) remains a devastating complication following total knee or total hip arthroplasty (TKA/THA). Nowadays, many studies focus on preventive strategies regarding PJI; however, the potential role of anesthesia in the development of PJI remains unclear.Patients and methods - All consecutive patients undergoing elective primary unilateral TKA or THA from January 2014 through December 2017 were included. Exclusion criteria included femoral fractures as the indication for surgery and previously performed osteosynthesis or hardware removal on the affected joint. Age, sex, BMI, ASA classification, type of arthroplasty surgery, type of anesthesia, duration of surgery, smoking status, and intraoperative hypothermia were recorded. Propensity score-matched univariable logistic regression analysis was used to control for allocation bias.Results - 3,909 procedures consisting of 54% THAs and 46% TKAs were available for analysis. 42% arthroplasties were performed under general anesthesia and 58% under spinal anesthesia. Early PJIs were observed in 1.7% of the general anesthesia group and in 0.8% in the spinal anesthesia group. The multivariable logistic regression model demonstrated an odds ratio for PJI of 2.0 (95% CI 1.0-3.7) after general anesthesia relative to the propensity score-matched patients who received spinal anesthesia.Interpretation - These results suggest a potential association between general anesthesia and early PJI. Future research using large-scale data is required to further elucidate this clinically relevant association.

Resurfacing hip arthroplasty better preserves a normal gait pattern at increasing walking speeds compared to total hip arthroplasty.

Background and purpose - Gait analysis performed under increased physical demand may detect differences in gait between total (THA) versus resurfacing hip arthroplasty (RHA), which are not measured at normal walking speed. We hypothesized that patients after RHA would reach higher walking speeds and inclines compared with THA. Additionally, an RHA would enable a more natural gait when comparing the operated with the healthy contralateral hip. Patients and methods - From a randomized controlled trial comparing THA with RHA with at least 5 years' follow-up patients with a UCLA score of more than 3 points (n = 34) were included for an instrumented treadmill gait analysis. 25 patients with a unilateral implant (primary analysis-16 THA versus 9 RHA) and 9 patients with a bilateral implant (sub-analysis-n = 5 RHA + THA; n = 4 THA + THA). Spatiotemporal parameters, ground reaction forces, and range of motion were recorded at increasing walking speeds and inclines. Functional outcome scores were obtained. Results - At a normal walking speed of 1.1 m/s and at increasing inclines no differences were recorded in gait between the 2 groups with a unilateral hip implant. With increasing walking speed the RHA group reached a higher top walking speed (TWS) (adjusted difference 0.07 m/s, 95% CI -0.11 to 0.25) compared with THA. Additionally, RHA patients tolerated more weight on the operated side at TWS (155 N, CI 49-261) and as such weight-bearing approached the unaffected contralateral side. For the RHA group a "between leg difference" of 8 N (CI 3-245) was measured versus -129 N (CI -138 to -29) for THA (adjusted difference 144 N, CI 20-261). Hip flexion of the operated side at TWS was higher after RHA compared with THA (adjusted difference 8°, CI 1.7-14). Interpretation - In this study RHA patients reached a higher walking speed, and preserved a more normal weight acceptance and a greater range of hip flexion against their contralateral healthy leg as compared with patients with a THA.

Low sensitivity of a-defensin (Synovasure) test for intra-operative exclusion of prosthetic joint infection.

Background and purpose - The Synovasure lateral flow test was developed as a rapid test for the detection or exclusion of periprosthetic joint infection (PJI). 3 studies have reported promising results on its diagnostic value in total joint revision surgery. We aimed to assess the sensitivity and specificity of the Synovasure test to exclude infection in patients undergoing revision surgery for suspected early aseptic loosening of a total hip or knee arthroplasty. Patients and methods - In a prospective study design, 37 patients who underwent revision surgery for suspected early aseptic loosening (< 3 years after primary arthroplasty) were included. The Synovasure test was used intraoperatively to confirm the aseptic nature of the loosening and 6 tissue cultures were obtained in all cases. Exclusion criteria were patients with a preoperatively confirmed PJI, acute revisions (< 90 days after primary arthroplasty) and cases with malpositioning, wear, or instability of the prosthesis. Results - 5 of the 37 patients were diagnosed with a PJI based on the intraoperative tissue cultures. In only 1 out of these 5 cases this was confirmed by the intraoperative Synovasure test. No tests were falsely positive. Interpretation - In this case series the Synovasure lateral flow test had a low sensitivity to exclude PJI in patients with suspected aseptic loosening. The role of the Synovasure lateral flow test in the intraoperative exclusion of PJI during revision surgery for suspected early aseptic loosening appears to be more limited than previously indicated.

Lessons learnt from early failure of a patient trial with a polymer-on-polymer resurfacing hip arthroplasty.

Background and purpose - Hip resurfacing (HR) is a treatment option promoted for hip arthritis in young and active patients. However, adverse reactions to metal are a concern and the search for non-metallic bearing options proceeds. We present the first clinical study performed in patients using a newly developed hydrophilic polymer-on-polymer hip resurfacing device. Patients and methods - After performing extensive hip simulator tests, biocompatibility testing and animal tests (ISO 14242-1,3; 10993-3,4,5,10,11), approval was obtained from the IRB committee to enroll 15 patients in the first clinical study in humans using this experimental polymer-on-polymer hip resurfacing device. All surgeries were done by 2 experienced hip resurfacing surgeons. Clinical scores and standard radiographs as well as routine MRIs were obtained at regular intervals. Results - The surgical technique proved feasible with successful implantation of the new device using PMMA cement fixation on both sides without complications. Postoperative imaging revealed a well-positioned and well-fixed polymer resurfacing hip arthroplasty in all 4 initial cases. All 4 patients were free of pain and had good function for the first 2 months. However, in all 4 cases early cup loosening occurred between 8 and 11 weeks after surgery, necessitating immediate closure of the study. All 4 patients had a reoperation and were revised to a conventional THA. Retrieval analyses confirmed early cup loosening at the implant-cement interface in all 4 cases. The femoral components remained well attached to the cement. The periprosthetic tissues showed only small amounts of polymeric wear debris and there was only a very mild inflammatory reaction to this. Interpretation - Early cup loosening mandated a premature arrest of this study. After additional laboratory testing this failure mode was found to be the result of a small, yet measurable contraction in the cup size after exposing these implants to biological fluid divalent ion fluctuations in vivo. Currently used preclinical tests had failed to detect this failure mechanism. Modification of the polymer is essential to overcome these problems and before the potential of a polymer-on-polymer resurfacing arthroplasty may be further evaluated in patients.

Bone mineral density changes in the graft after acetabular impaction bone grafting in primary and revision hip surgery.

Background and purpose - Impaction bone grafting (IBG) is an established method in hip revision surgery to reconstruct loss of bone stock. There is limited knowledge concerning the actual bone remodelling process within the allograft. We investigated with repeated bone mineral density (BMD) measurements the biological process of bone remodelling in the allograft in vivo. We hypothesized that an initial decrease in BMD would be followed by an increase towards baseline values. Patients and methods - Dual-energy X-ray absorptiometry (DXA) was used to measure BMD values in 3 regions of interest (ROI) in 20 patients (average age at surgery 70 years, 11 males) after an acetabular reconstruction with IBG and a cemented cup. A postoperative DXA was used as baseline and DXA was repeated at 3 and 6 months and at 1 and 2 years. The Oxford Hip Score (OHS), the 12-Item Short Form Health Survey (SF12), and a 0 to 100 mm visual analogue scale (VAS) for pain and satisfaction were obtained simultaneously. Results - The overall mean BMD in the IBG regions increased significantly by 9% (95% CI 2-15) at 2 years' follow-up. In the cranial ROI BMD increased 14% (CI 6-22), whereas the BMD in the medial and caudal ROI showed an increase of 10% (CI 1-18) and 4% (CI -6-16), respectively. The OHS, SF12-mental, and VAS for pain all improved statistically significantly 2 years after surgery, with a mean VAS for satisfaction of 77 (CI 63-90) out of 100 points. The SF12-physical showed non-significant improvement. Interpretation - The BMD in the allograft gradually increased after IBG for acetabular reconstruction arthroplasties, particularly in the cranial ROI. An initial decrease in the BMD was not encountered. These BMD changes, as proxy measurements for bone remodeling, may indicate progressive apposition of vital new host bone in the grafted area.

High incidence of intraoperative calcar fractures with the cementless CLS Spotorno stem.

INTRODUCTION: This study reports on the incidence of intraoperative calcar fractures with the cementless Spotorno (CLS) stem, and the potential role of a learning curve and implant positioning is investigated. METHODS: After introduction of the CLS stem, 800 consecutive cementless total hip arthroplasties (THA) were analyzed. The incidence of calcar fracture in the first 400 THA was compared with the second 400 THA, in order to study a potential learning curve effect. According to the instruction for users, varus positioning of the stem was avoided and a femoral neck osteotomy was aimed relatively close to the lesser trochanter since these are assumed to be correlated with calcar fractures. Implant positioning (neck-shaft angle, femoral offset and osteotomy-lesser trochanter distance) was measured on postoperative pelvic radiographs of all THA with calcar fractures and 100 randomly selected uncomplicated control cases. RESULTS: Seventeen (2.1%) intraoperative calcar fractures were recorded. The incidence of calcar fracture differed between the first 400 THA (n = 11) and the second 400 THA (n = 6). This difference was not statistically significant (p = 0.220); however, these numbers indicate a trend toward a learning effect. No significant difference in stem positioning nor the height of the femoral neck osteotomy was measured between THA with a calcar fracture (n = 17) and the control cases (n = 100). CONCLUSIONS: We report on a high incidence of intraoperative calcar fractures with the use of a CLS stem. The risk for calcar fractures remains clinically significant even after adequate implant positioning in the hands of experienced hip surgeons. Surgeons should be aware of this implant related phenomenon and be alert on this phenomenon intraoperatively.

Metal ion levels and functional results following resurfacing hip arthroplasty versus conventional small-diameter metal-on-metal total hip arthroplasty; a 3 to 5year follow-up of a randomized controlled trial.

We present an update of a randomized controlled trial on 71 patients (<65 years) who received either a resurfacing hip arthroplasty (RHA) (n=38) or cementless 28-mm metal-on-metal (MoM) total hip arthroplasty (THA) (n=33). Metal ion levels and functional outcome scores were analyzed with a mean follow-up of 58 months (SD 8.1). No clear shifts in relatively good outcome was encountered between RHA and THA. Metal ion levels appear to equalize between groups after 3 years. Median cobalt and chromium remained below 1.3 µg/L throughout follow-up in both groups. Six revisions were performed, of which three for pseudotumor formation (one THA, two RHA). In conclusion there were no clinical differences between the two groups and metal ion levels were lower than other series remained low, however, pseudotumor formation was not eliminated.

Changes in bone mineral density and femoral neck narrowing in the proximal femur three to five years after hip resurfacing versus conventional total hip arthroplasty.

We studied whether bone mineral density (BMD) is preserved without significant femoral neck narrowing (FNN) after hip resurfacing (RHA) (n=42) versus small diameter metal-on-metal total hip arthroplasty (MoM THA) (n=40). In this three to five year randomized trial BMD was measured in the calcar with dual energy absorptiometry (DXA) preoperatively, at three and six months, one, two, three and five years postoperatively. Four additional BMD regions of interest (ROIs) and femoral neck narrowing (FNN) were measured after RHA. BMD in the calcar increased to 107% (P<0.001) at one year and remained stable. Additional ROIs in the femoral neck and trochanter-area BMD changes fluctuated between 99.9% and 104.1%. FNN was minimal with a mean of 1.3% at three years. After THA BMD decreased in the calcar to 80% at one year (P<0.001) and stabilized. This bone stock preserving nature of RHA must be weighed against potential disadvantages caused by specific metal-on-metal bearing problems.

Modular necks in primary hip arthroplasty without anatomical deformity: no clear benefit on restoration of hip geometry and dislocation rate. An exploratory study.

Modular necks were introduced in total hip arthroplasty (THA) to improve restoration of hip-geometry and reduce dislocation-rates. This presumed advantage was evaluated retrospectively for patients with arthritis in otherwise anatomically normal hips. Restoration of hip-geometry was assessed on preoperative and postoperative calibrated radiographs in 95 consecutive primary THAs with a modular neck design and compared with 95 match controlled THAs with a similar monoblock stem. No significant differences were seen in restoration of body moment arm, leg length and cupangle. Offset restoration revealed a borderline significant difference (P = 0.48) with higher values for the monoblock stem. In both groups 4 dislocations within one year were encountered. In this study modular necks did not reveal a clear benefit in restoring hip geometry and dislocation rate after straightforward THA.

Excessive polyethylene wear and acetabular bone defects from standard use of a hooded acetabular insert in total hip arthroplasty.

PURPOSE: In total hip arthroplasty (THA) the use of a polyethylene (PE) insert with a hooded rim can be considered to reduce dislocation risks. This benefit has to be balanced against the potential introduction of impingement of the femoral component on this rim. We present a case series of early acetabular revisions for excessive PE wear and acetabular bone defects from overuse of such a hooded rim insert. MATERIAL AND METHODS: Twenty-eight patients with 34 consecutive early acetabular revisions were evaluated on failure mechanism. One type of implant was used in all cases. Standard pelvic radiographs and pre-operative CT scans were used to quantify PE wear, implant positioning and acetabular bone defects. RESULTS: An acetabular revision with impaction grafting was performed in all cases with a mean cup survival of ten years (range 1.3-19.3). No concurrent stem revisions were necessary. Overall implant positioning was adequate with a mean cup inclination of 45° (range 39-57) and anteversion of 25° (range eight to 45). The mean PE wear was 0.24 mm/year (range 0.00-1.17). The mean acetabular bone defect on pelvic CT scans was calculated as 352 mm² (range zero to 1107) and 369 mm² (range zero to 1300) in the coronal and transversal planes, respectively. A hooded acetabular insert was retrieved in all cases and profound PE wear, typically from the posterior hooded rim, was encountered. CONCLUSION: The use of hooded acetabular inserts may be considered to improve implant stability intra-operatively. This case series clearly presents that together with these devices, component impingement with concordant complications such as accelerated PE wear may be introduced. Standard use of these stabilizing inserts should thus be avoided.

Controversies around hip fracture treatment: clinical evidence versus trends from national registries.

PURPOSE: Several controversies in the optimal treatment of femoral neck fractures persist, together with large variations in clinical practice. METHODS: A narrative literature review covering 4 current controversies in the surgical management of femoral neck fractures (total hip arthroplasty (THA) versus hemiarthroplasty (HA), cemented versus uncemented HA, internal fixation versus arthroplasty, operative versus non-operative) was performed. Available literature was balanced against annual trends in the management of femoral neck fractures from the public domain of several national registries (Sweden, Norway, The Netherlands, Australia and New Zealand). RESULTS: For most controversies, the literature provides stronger evidence than is reflected by variations encountered in daily practice. Implementation of clinical evidence tends to lag behind and important differences exist between countries. CONCLUSIONS: Trends of clinical practice from national registries indicate that implementation of available clinical evidence needs to be improved.

Multiplex PCR test as an intra-operative diagnostic tool for periprosthetic joint infection in presumed aseptic revision hip and knee arthroplasty: a 1-year follow-up study of 200 cases.

Automated custom-made multiplex PCR techniques (mPCR) have become commercially available and are designed for intra-operative screening of concurrent periprosthetic joint infections (PJIs). The purpose of this study was to evaluate the value of a positive mPCR test in presumed aseptic revision total hip (THA) and knee (TKA) arthroplasties after a 1-year follow-up. In an earlier study, such an automated mPCR technique (Unyvero ITI G2; Curetis, Holzgerlingen, Germany) was tested on intra-operatively obtained synovial fluid in 200 patients with a presumed aseptic TKA or THA revision. At the time of revision, no therapeutic consequences were attached to a positive test result since treating personnel were blinded for the test results. We retrospectively reviewed the outcome of cases with respect to the occurrence of PJIs using the European Bone and Joint Infection Society (EBJIS) criteria during a 1-year follow-up postoperatively. A total of 10 out of 200 patients had a positive mPCR test result at the time of revision. Of these 10 cases, none encountered outcome parameters fulfilling the criteria to diagnose PJIs in the first year after surgery, and one required re-revision surgery for reasons other than infection. Of the other 190 negative mPCR cases, none developed a PJI. A positive mPCR test at the time of presumed aseptic revision surgery did not correspond with intra-operatively obtained tissue cultures, and none of the encountered positive mPCR tests had developed a PJI at the 1-year follow-up. We recommend careful evaluation and monitoring of modern diagnostic tests before widespread use.