Optimized decision algorithm for the microbiological diagnosis of osteoarticular infections in adults using synovial fluid samples: a prospective study in two French hospitals including 423 samples of synovial fluid.

No consensus exists about the techniques to use for microbiological diagnosis of bone and joint infections (BJIs). The objective herein was to define an algorithm to optimize BJI diagnosis in adults using various bacteriological methods on synovial fluid samples. This prospective multi-center study included 423 synovial fluids collected from adult patients with suspected BJIs. Culture (using five solid media, an enrichment broth, and blood culture bottles), universal 16S rRNA PCR followed by Sanger sequencing, and seven specific bacterial PCRs were systematically performed. Combinations of methods were compared to arrive at the optimized algorithm. Among 423 synovial fluids, 242 infections were diagnosed (57.2 %): 213 mono- and 29 poly-microbial for a total of 284 bacteria (staphylococci at 54.6 %, streptococci-enterococci at 16.5 %, Gram-negative bacilli at 15.5 %, anaerobic species at 8.8 %). Comparing culture techniques, blood culture bottles had the highest sensitivity (67.6 % for pediatric and 63.9 % for anaerobic bottles) but are not sufficient alone and require being combined with solid media. The 16S rDNA PCR detected only 52.3 % of the bacteria, whereas specific PCRs had a higher sensitivity (Staphylococcus spp. at 66.2 %, S. aureus at 85.2 %, Streptococcus spp. at 91.2 %). Based on these results, an algorithm was proposed associating three solid media; inoculation into blood culture bottles; and 16S, Staphylococcus spp., and Streptococcus spp. PCRs, which would have detected 90.5 % of bacteria in the present cohort versus 79.2 % using all culture techniques on synovial fluid. This prospective study shows that a combination of culture and molecular methods on synovial fluids allows the optimization of bacterial detection.

Antibiotic Prophylaxis in One-Stage Revision of Septic Total Knee Arthroplasty: A Scoping Review.

BACKGROUND: Total knee replacement (TKA) is becoming a routine procedure in orthopedic surgery. One of the possible complications of this surgery is periprosthetic joint infection (PJI). The purpose of this study is to identify, through a literature review, which antibiotic is used as prophylaxis for septic one-stage revision TKA and what is the rationale for its use. METHODS: We searched: MEDLINE, Embase, PsycINFO on Ovid, the Cochrane Library, and the Google Scholar Database. The searches were limited by date (January 2005 to September 2022) and to the English language. All types of original research were considered, including prospective or retrospective longitudinal studies, cross-sectional studies, and randomized trials. The specific search terms were ((antibiotic [MeSH]) AND (prophylaxis)) and (TKA OR TKR OR "Arthroplasty, Replacement, Knee" [MeSH] OR ((knee) adj2 (replace* OR arthroplasty* OR prosthe*))). RESULTS: Despite our research efforts, we found no article capable of answering the question of which antibiotic to use as surgical prophylaxis for a septic revision one-stage TKA. CONCLUSIONS: Although the research results are inconclusive, we would recommend using the same antibiotic prophylaxis as for primary joint replacement, i.e., cefazolin, as it was recommended for its low side effect rate and relative effectiveness.

Masquelet's induced membrane technique associated with Reamer Irrigation Aspiration grafting and intramedullary Nailing (MaRIAN) for chronic diaphyseal osteomyelitis of the lower limb.

INTRODUCTION: Masquelet's induced membrane technique offers a definitive contribution to the treatment of diaphyseal osteomyelitis. To overcome its drawbacks while maintaining its principles, technical modifications have been proposed: antibiotic cement, femoral intramedullary autograft harvested by RIA (Reamer Irrigation Aspiration) and interlocking nails. MATERIAL AND METHOD: This retrospective study gathered patients with chronic osteomyelitis of the femur or tibia. The first surgical stage consisted of bone resection in the healthy zone and use of a gentamicin cement spacer to fill the bone defect. The second stage consisted of the placement of a statically locked intramedullary nail associated with a bone autograft using the RIA technique. RESULTS: Among this group of 12 men with diaphyseal osteomyelitis; 9 tibial and 2 femoral, and 1 knee nonunion, the mean bone defect was 7.3cm (±6.7). The mean time between the 2 stages was 2.7months (±3) with a mean antibiotic period of 3.25weeks (±3). There was a femoral diaphyseal fracture at the donor site, and a wrong trajectory intraoperatively during the RIA. Two patients with tibial nonunion presented with nail rupture without septic recurrence. A septic recurrence was healed by removal of the nail. At a minimum follow-up of 18months, with an average of 5years, consolidation was complete without infectious recurrence. Despite the statistical weakness related to the size of the cohort, the resumption of early weight bearing (OR=-7.68 95% CI [-13.33 to -2.08] (p=0.01)) and nail dynamization seemed to have an impact on the formation of complete consolidation (OR=-0.86 95% CI [-1.39 to -0.33] (p=0.007)). DISCUSSION AND CONCLUSION: This short series, compared to the literature, demonstrated that the proposed technical modifications improved the overall management of this rare and challenging condition while maintaining the reliability of the original technique. Dynamization was also seen to be of particular interest. LEVEL OF EVIDENCE: IV, retrospective study.

Optimal Combination of Femoral Tunnel Orientation in Anterior Cruciate Ligament Reconstruction Using an Inside-out Femoral Technique Combined With an Anterolateral Extra-articular Reconstruction.

BACKGROUND: The optimal orientation of the anterolateral extra-articular reconstruction (ALLR) femoral tunnel to avoid collision with the anterior cruciate ligament reconstruction (ACLR) femoral tunnel is not clearly defined in the literature. PURPOSE: To define the optimal combination of orientations of the ALLR femoral tunnel and the ACLR femoral tunnel using an inside-out technique to minimize risk of collision between these tunnels. STUDY DESIGN: Descriptive laboratory study. METHODS: Three-dimensional reconstruction of magnetic resonance imaging scans of 40 knees after an isolated ACLR with an inside-out femoral technique was used to assess the collision risk between ACLR and virtual ALLR tunnels. The optimal ACLR tunnel orientation was defined as having the safest distance from the ALLR tunnel. A second collision analysis was performed on all patients presenting with an optimal orientation of the ACLR tunnel to then define the optimal ALLR tunnel orientation. The potential for trochlear damage was also studied. A collision risk of 0% to 5% was considered acceptable and referred to as "low risk." RESULTS: The only ALLR tunnel orientation presenting a low risk of collision with the ACLR tunnel was with an axial angle of 40° anteriorly and a coronal angle of 0°. This orientation presented a 48% risk of trochlear damage with the guide wire of the ALLR tunnel. The more posterior the orientation of the ACLR, the larger the distance from the ALLR tunnel. Among the 22 patients presenting with an optimal ACLR tunnel (alpha angle superior to 40°), the ALLR tunnels aimed with 1 of these 3 orientations presented a low risk of tunnel collision and trochlear damage: 40° axial and 10° coronal, 35° axial and 5° coronal, or 30° axial and 0° coronal. CONCLUSION/CLINICAL RELEVANCE: To minimize risk of tunnel collision or trochlear damage when combining an inside-out ACLR with an ALLR, the ACLR tunnel should be performed with a posterior orientation (alpha angle >40°), and the ALLR tunnel should be aimed with 1 of 3 orientations: 40° axial and 10° coronal, 35° axial and 5° coronal, or 30° axial and 0° coronal.

Survival and complications of total hip arthroplasty using third-generation dual-mobility cups with non-cross-linked polyethylene liners in patients younger than 55years.

BACKGROUND: In younger patients, total hip prostheses are subjected to wide motion ranges and wear-inducing forces. Dual-mobility cups (DMCs) are effective in decreasing the risk of dislocation. However, wear and osteolysis have been reported with first-generation DMCs. These complications have not been assessed in younger patients managed with third-generation DMCs associated with a lower risk of intra-prosthetic dislocation (IPD). We therefore designed a retrospective study of patients younger than 55years at THA with third-generation DMCs. Our objectives were to evaluate (1) the complication rate, and (2) the survival rate. HYPOTHESIS: The rate of complications of THA with third-generation DMCs in patients younger than 55years of age is comparable to that in the general population of THA patients. MATERIAL AND METHODS: This retrospective study included 79 consecutive patients (91 hips) who had total hip arthroplasty (THA) between 2007 and 2012. We included all patients younger than 55years who underwent primary THA with a third-generation DMC and a liner made of non-cross-linked polyethylene. The patients were evaluated clinically and radiologically. RESULTS: Mean follow-up was 9.8years (range: 2-13years). At last follow-up, no patient had experienced prosthetic dislocation or IPD. Aseptic and septic cup loosening each occurred in 1 patient. In all, 7 (7.7%) patients required revision surgery with exchange of at least one component (cup loosening, n=2; neck fracture with a short stem fixed to the neck, n=1; peri-prosthetic femoral fracture, n=1; infection, n=1; and femoral-stem loosening, n=2). Peri-acetabular osteolysis developed in 2 (2.2%) hips. Cup survival to aseptic loosening was 98.9% (95% confidence interval, 97%-100%) and survival to revision for any reason except infection was 95.6% (95% confidence interval, 82%-100%). DISCUSSION: In patients younger than 55years, third-generation DMCs were associated with absence of prosthetic dislocation, absence of IPD, and a low revision rate for cup loosening, in the medium term. These implants therefore constitute a viable treatment option in younger patients requiring THA. LEVEL OF EVIDENCE: IV, retrospective study.

What Are the Sonographic Outcomes of Acute Achilles Tendon Rupture? Nonoperative Versus Surgical Repair?

INTRODUCTION: The objective was to compare the two-year ultrasonographic outcomes in a consecutive series of patients with acute Achilles tendon rupture (ATr), either treated surgically or nonoperatively. MATERIALS AND METHODS: This is a prospective, single-center, consecutive series. All patients presenting with acute ATr were included and divided into two groups: surgical or nonoperative groups. At two years, patients were evaluated clinically and sonographically. The parameters studied were length of the tendon on the rupture side (LTCR) and on the contralateral side (LTCS), ratio LTCR/LTCS, maximum anteroposterior diameter on the rupture side (DAPMR), maximum surface area on the rupture side (SMR), maximum anteroposterior diameter on the contralateral side (DAPMS), and maximum surface area on the contralateral side (SMS). Morphological changes in tendon structure were reported. RESULTS: Thirty patients were included. No difference in functional score was observed between both groups. In the nonoperative group, there is a significant difference between: LTCR and LTCS; DAPMR and DAPMS. In the surgical group, there is a significant difference between: LTCR and LTCS; DAPMR and DAPMS; SMR and SMS. There is a significant difference when comparing SMR/SMS between both groups. In terms of morphological changes in tendon structure, there were differences. CONCLUSION: At two years, there was no difference in functional outcomes between the two groups. In both groups, AT were lengthened and thickened without differences between groups. There was a significant difference when comparing the ratio SMR/SMS between groups. Ultrasound examination demonstrated different morphological changes in tendon structure depending on the treatment performed.

Salmonella infection after anterior cruciate ligament reconstruction: A case report.

BACKGROUND: Infections after anterior cruciate ligament reconstruction (ACLR) are rare. No cases of Salmonella infection have been described to our knowledge. CASE SUMMARY: We describe a rare case of Salmonella infection in a 23-year-old patient following an ACLR. The patient presented with subacute septic arthritis, 26 d after a hamstring autograft ACLR. The pathogen, Salmonella enterica typhimurium was isolated by bacteriological sampling of the first arthroscopic lavage. Two arthroscopic lavages were required, with intravenous antibiotic therapy for two weeks with cefotaxime and ciprofloxacin, followed by oral antibiotics with amoxicillin and ciprofloxacin for a total duration of three months. This approach treated the infection but two years after the septic arthritis, faced with ongoing knee instability due to graft damage, a revision ACLR with a bone-tendon-bone graft was performed. At the last follow-up, full range of knee motion had been achieved and sports activities resumed. CONCLUSION: Infection after ACLR is rare and requires an early diagnosis and management in order to treat the infection and prevent arthritis-related joint cartilage destruction and damage to the graft.

Methods and probability of success after early revision of prosthetic joint infections with debridement, antibiotics and implant retention.

Prosthetic joint infection (PJI) is a rare-and dreaded-complication of arthroplasty requiring multidisciplinary care. Given the dual goal of treating the infection and maintaining satisfactory function, it is preferable to determine how and when the implanted components can be retained. Bacteria and fungi organize themselves into biofilms that shield them from antibiotics and the immune system. This biofilm is in place after 15 days of active infection. Some antibiotics have a better activity on biofilms. The following factors have a negative impact on the probability of a successful debridement, antibiotics and implant retention (DAIR) intervention: fracture or revision, use of cement, bacteremia, kidney and/or liver failure, immunosuppression and elevated CRP. Hematogenous infections have a worse prognosis than early postoperative infections. Using a decision algorithm increases the chances of DAIR being successful. The KLIC score applies to early postoperative infections (<4 weeks postoperative and<3 weeks from the first signs) while the CRIME-80 score applies to hematogenous infections (<3 weeks from the first signs). Arthroscopic treatments have no role here, whereas DAIR through an arthrotomy is well standardized. Wide spectrum antibiotic therapy, secondarily adapted to the causative microorganism, is indicated for a total of 3 months. The results against the infection are mixed, although following a decision algorithm resolves the infection in about 75% of cases. The functional outcomes and quality of life are close to those of patients who have undergone primary joint replacement. It is not recommended to carry out a second DAIR if the first one fails. It is logical to apply the principles set out for the hip and knee to other joint replacements, and to use the same algorithm. For the upper limb, and especially for reverse shoulder arthroplasty, one must be careful about Cutibacterium acnes infections as they are hard to diagnose. Surgeons should not hesitate to contact a referral center for any PJI, although it is preferable that early infections be treated at the facility that performed the implantation.

Dual mobility cups for total hip arthroplasty: tips and tricks.

Since its creation in 1974, the Dual Mobility Cup (DMC) has been gaining in popularity, especially in the past decade. This intensive use could lead to inappropriate use and consequently to an increased complication rate. Compliance with conceptual requirements and surgical techniques will prevent the occurrence of complications that can be wrongly attributed to implants. In this context, we feel that it is essential to share our tips and tricks as well as an overview and an explanation of common errors, based on more than 45 years of clinical and research experience. From basic principles, including indications, implant choice and implant compatibility, to surgical tips, in this article orthopedic surgeons will find a practical overview of DMC in order to use it safely and with confidence.

Low Revision Rates at More Than 10 Years for Dual-Mobility Cups Cemented Into Cages in Complex Revision Total Hip Arthroplasty.

BACKGROUND: Instability and aseptic loosening are the two main complications after revision total hip arthroplasty (rTHA). Dual-mobility (DM) cups were shown to counteract implant instability during rTHA. To our knowledge, no study evaluated the 10-year outcomes of rTHA using DM cups, cemented into a metal reinforcement ring, in cases of severe acetabular bone loss. We hypothesized that using a DM cup cemented into a metal ring is a reliable technique for rTHA at 10 years, with few revisions for acetabular loosening and/or instability. METHODS: This is a retrospective study of 77 rTHA cases with severe acetabular bone loss (Paprosky ≥ 2C) treated exclusively with a DM cup (NOVAE STICK; Serf, Décines-Charpieu, France) cemented into a cage (Kerboull cross, Burch-Schneider, or ARM rings). Clinical scores and radiological assessments were performed preoperatively and at the last follow-up. The main endpoints were revision surgery for aseptic loosening or recurring dislocation. RESULTS: With a mean follow-up of 10.7 years [2.1-16.2], 3 patients were reoperated because of aseptic acetabular loosening (3.9%) at 9.6 years [7-12]. Seven patients (9.45%) dislocated their hip implant, only 1 suffered from chronic instability (1.3%). Cup survivorship was 96.1% at 10 years. No sign of progressive radiolucent lines were found and bone graft integration was satisfactory for 91% of the patients. CONCLUSION: The use of a DM cup cemented into a metal ring during rTHA with complex acetabular bone loss was associated with low revision rates for either acetabular loosening or chronic instability at 10 years.

Contemporary rotating hinge arthroplasty can safely be recommended in complex primary surgery.

PURPOSE: The objective was to evaluate clinical and radiological outcomes, survival rate and complications of primary contemporary rotating hinged total knee arthroplasty (CRH-TKA). METHODS: Through a national multicenter retrospective study (14 centers), 112 primary CRH-TKA performed between 2006 and 2011 were included. Indications were: severe frontal plane deformity (55%), inflammatory, constitutional, congenital or post-trauma arthritis (26%), ligament laxity (10%), primary osteoarthritis (9%). Population was elderly (68 ± 13), sedentary (37.5% with a Devane score ≥ 3) and with important comorbidities (87% with ASA score ≥ 2). A clinical (KSS, Oxford scores) and radiological evaluation (implant loosening), as well as survival and reoperation rates assessment, were performed. RESULTS: At last follow-up (7 ± 3 years), KSS and Oxford scores were 64 ± 43 and 33 ± 10 each with a significant improvement of both scores overtime (respectively, p = 0.047 and p < 0.001). Twenty-eight complications (25%) were reported: 12 infections, 6 stiffness, 5 aseptic loosening and 5 patellofemoral instabilities. All in all, 91% (n = 102) of implants were still sealed and in place, 6% (n = 7) required revision and 3% (n = 3) were loose but could not undergo revision due to weak general health status. Mortality rate (18%, n = 20), linked to comorbidities, was high. CONCLUSION: Clinical outcomes and survival of primary CRH-TKA are acceptable given the difficult and complex clinical situations it faced, but with high infection rate. In primary surgery, for patients with severe deformity, bone loss or ligament laxity, the use of CRH-TKA can be recommended. The choice of these implants must remain cautious and limited to situations not allowing the use of less constrained implants. LEVEL OF EVIDENCE: Retrospective therapeutic and cohort study, Level III; retrospective case series, Level IV.

What are the influencing factors on hip and knee arthroplasty survival? Prospective cohort study on 63619 arthroplasties.

BACKGROUND: Body mass index is used by the World Health Organization to classify obesity. While obesity influences the onset of arthritis and type-2 diabetes, its effect on implant survival is still open to debate, with conflicting results from clinical and registry studies, as well as meta-analyses. Other known factors such as gender or diabetes status could ponderate or mask the effect of BMI on implant survival. HYPOTHESIS: Our hypothesis was BMI influenced hip and knee arthroplasty survival, when results were made independent of gender and diabetes status. PATIENT AND METHODS: A registry study was designed on 30733 Total Hip Arthroplasties (THA), 28483 Total Knee Arthroplasties (TKA), 3754 Uni compartmental Knee Arthroplasties (UKA) and 649 Hinged Knee arthroplasties (HK), from 01/01/2003 to 31/12/2015. Mean follow-up was 5.5 years. Diabetes status was added to the model. Each arthroplasty survival was tested for age at implantation, gender, diabetes status, implant characteristics and specifically BMI, taking into account gender and diabetes status. RESULTS: Gender had a strong influence on arthroplasty results. Age also influenced arthroplasty survival, especially aseptic loosening; a young age would lower implant survival. Diabetes had an influence in hip survival, but its influence on septic loosenings in TKA wasn't proven (p=0.065). A mobile liner and/or a cruciate retaining knee were factors increasing the risk of revision. Weight influenced THA survival, especially aseptic loosening, but didn't have a measurable effect in any other arthroplasty. BMI was not found to influence any arthroplasty survival, whatever the endpoint, when diabetes and gender were taken into account. DISCUSSION: Gender, age and diabetes influenced survival of the lower limb arthroplasties, whereas BMI did not. Only weight did influence THA results and should be used instead of BMI. CONCLUSION: Studies on arthroplasty survival should systematically mention gender and diabetes status and beware of potential group incomparability. LEVEL OF EVIDENCE: III, cohort study.

Outcomes of Augmented Dual Mobility Acetabular Cups.

INTRODUCTION: Total hip arthroplasty (THA) in patients with acetabular bone defects is associated with a high risk of dislocation and aseptic loosening. No studies to date have examined the use of uncemented and augmented dual mobility cups (DMC) in patients with acetabular defects. We hypothesized that the use of augmented DMC under these conditions would reduce the dislocation rate and lead to satisfactory bone integration in the medium term despite acetabular bone defects. MATERIALS AND METHODS: This continuous multicenter study included all cases of augmented DMC performed between 2010 and 2017 in patients with acetabular bone loss (Paprosky 2A: 46%, 2B: 32%, 2C: 15% and 3A: 6%). The indications for implantation were revisions for cup aseptic loosening (AL) (n=45), femoral stem AL (n=3), bipolar AL (n=11), septic loosening (n=10), periprosthetic fracture (n=5), chronic dislocation (n=4), intraprosthetic dislocation (n=2), cup impingement (n=1), primary posttraumatic arthroplasty (n=8), and acetabular dysplasia (n=4). The clinical assessment consisted of the Harris hip score (HHS) and Merle d'Aubigné Postel score (MDP), along with preoperative and final follow-up radiographs. The primary endpoint was surgical revision for aseptic acetabular loosening or the occurrence of dislocation. RESULTS: Overall, 93 patients were reviewed at a mean follow-up of 5.3 ± 2.3 years [0, 10]. As of the last follow-up, the acetabular cup had been changed in five cases: 3 AL (3.2%) and 2 infections (2.1%). Thus the overall survivorship of the cup was 94.6% and the survivorship for AL was 96.8%. Three patients (3%) suffered a dislocation. At the last follow-up visit, the mean MDP and HHS scores were 14.75 and 72.15, respectively, which reflected significant improvements relative to the preoperative scores (p < 0.05). CONCLUSION: Use of an uncemented and augmented DMC in cases of acetabular bone defect leads to satisfactory medium-term results with low dislocation and loosening rates. We recommend its use in these cases.

Use of morselized allografts for acetabular reconstruction during THA revision: French multicenter study of 508 cases with 8 years' average follow-up.

BACKGROUND: In the context of acetabular reconstruction, bone defects can be filled with processed or unprocessed bone allografts. Published data are often contradictory on this topic and few studies have been done comparing processed allografts to fresh-frozen ones. This led us to conduct a large study to measure the factors impacting the survival of THA revision: (1) type of allograft and cup, (2) technical factors or patient-related factors. HYPOTHESIS: Acetabular reconstruction can be performed equally well with frozen or processed morselized allografts. MATERIALS AND METHODS: This retrospective, multicenter study of acetabular reconstruction included 508 cases with a minimum follow-up of 5 years. The follow-up for the frozen grafts was shorter (7.86 years±1.89 [5-12.32]) than that of the processed grafts (8.22 years±1.77 [5.05-15.48]) (p=0.029). However, the patients were younger at the time of the primary THA procedure in the frozen allograft group (51.5 years±14.2 [17-80]) than in the processed group (57.5 years±13.0 [12-94]) (p<0.001) and were also younger at the time of THA revision (67.8 years±12.2 [36.9-89.3] versus 70 years±11.7 [25-94.5]) (p=0.041). RESULTS: There were more complications overall in the frozen allograft group (46/242=19.0%) than the processed allograft group (35/256=13.2%) (p=0.044) with more instances of loosening in the frozen group (20/242 [8.2%]) than in the processed group (6/266 [3.3%])(p=0.001). Conversely, the dislocation rate (16/242=6.6% vs. 17/266=6.4%) (p=0.844) and infection rate (18/242=7.4% vs. 15/266=5.7%) (p=0.264) did not differ between groups. The subgroup analysis reveal a correlation between the occurrence of a complication and higher body mass index (BMI) (p=0.037) with a higher overall risk of complications in patients with a BMI above 30 or under 20 (p=0.006) and a relative risk of 1.95 (95% CI: 1.26-2.93). Being overweight was associated with a higher risk of dislocation (relative risk of 2.46; 95% CI: 1.23-4.70) (p=0.007). Loosening was more likely to occur in younger patients at the time of the procedure (relative risk of 2.77; 95% CI: 1.52-6.51) (p=0.040) before 60 years during the revision. Lastly, patients who were less active preoperatively based on the Devane scale had an increased risk of dislocation (relative risk of 2.51; 95% CI: 1.26-8.26) (p=0.022). DISCUSSION: Our hypothesis was not confirmed. The groups were not comparable initially, which may explain the differences found since the larger number of loosening cases in the frozen allograft group can be attributed to group heterogeneity. Nevertheless, morselized allografts appear to be suitable for acetabular bone defect reconstruction. A randomized study would be needed to determine whether frozen or processed allografts are superior. LEVEL OF EVIDENCE: III, comparative retrospective study.

Unilateral versus bilateral total knee arthroplasty: A registry study on survival and risk factors.

BACKGROUND: Bilateral cases, representing at least 25% of total knee arthroplasties (TKA), could convey a statistical bias linked to dependency. Registries allow exploring this issue, susceptible to question surgeon validated protocols. Do bilateral total knee arthroplasties behave differently than unilateral knees in terms of implant survival? HYPOTHESIS: Bilateral TKA have a better survival than unilateral TKA. PATIENTS AND METHODS: A number of 14,652 bilateral and 27,440 unilateral TKAs were compared. Influencing factors were tested with hazard ratios applied on bilateral knees. RESULTS: Bilateral knees had a better survival (p<0.001). Delay between first and second side surgeries had an influence on survival of the first knee: if below a year, the first knee survival was superior to the second knee; more than three years between both arthroplasties significantly decreased the survival of the first implant. If the first knee was revised, the hazard ratio for revision of the second implant was 3.5. DISCUSSION: Series should include separate evaluations of bilateral cases, because they have a better survival than unilateral knees. A long delay between both knee replacements could impact both implant survivals. Level of Evidence III, Cohort Comparative Study.

Dual mobility cups in total hip arthroplasty after failed internal fixation of proximal femoral fractures.

INTRODUCTION: Performing total hip arthroplasty (THA) following failed internal fixation of proximal femur fractures is associated with an elevated risk of implant dislocation. We hypothesized that using a dual mobility (DM) cup will help to reduce the risk of postoperative instability in this specific context. MATERIAL AND METHODS: This was a retrospective study of 33 consecutive patients who underwent DM THA following failed internal fixation of a proximal femur fracture. The clinical assessment consisted of the Postel-Merle d'Aubigné and HHS scores along with an analysis of preoperative and follow-up radiographs. The primary outcome was the occurrence of implant dislocation. RESULTS: At the last follow-up (44±24 months), 7 patients had died and 0 were lost to follow-up. Only one dislocation had occurred (3%). The mean PMA and HSS scores of 14.8 and 80 respectively were significantly better than the preoperative scores. There were no cases of aseptic loosening. CONCLUSION: The use of DM cups in the context of THA following failed internal fixation of proximal femur fractures helps to reduce the risk of dislocation. Thus DM cups are recommended in this indication with high risk of postoperative instability.

Medial patellofemoral ligament reconstruction with or without tibial tubercle transfer is an effective treatment for patellofemoral instability.

PURPOSE: The hypotheses were that medial patellofemoral ligament reconstruction (MPFLr) would improve the long-term symptoms of patellofemoral Instability (PFI) and control patellar tilt, based on computed tomography (CT), and that the addition of a TT transfer, when it is necessary, would not deteriorate the outcome. The purpose of this study was to evaluate the long-term clinical and radiographic outcomes of a large series of MPFLr, either isolated or associated with a TT transfer. METHODS: From 133 MPFLr with a minimum of 4 years postoperatively, three groups were defined: isolated MPFLr, MPFLr with tibial tubercle (TT) medialisation or MPFLr with TT medialisation and distalisation. IKDC and Kujala scores were evaluated. Patellar tilt was evaluated on the patient's preoperative and the last available radiograph, and on CT scan measurements performed preoperatively and at 6-month postoperatively. RESULTS: The mean follow-up was 6.3 ± 1.7 years [4.1-10.3] and four patients reported recurrent patellar dislocation. Between pre and postoperative at last follow-up a significant improvement in IKDC and Kujala functional scores was observed (P < 0.01), with no difference between the three groups. Regarding patellar tilt, there were significant decreases in Laurin and Merchant angles and an improvement of the Maldague stage (P < 0.01). The CT analysis of patellar tilt also demonstrates a significant improvement of the patella tilt (P < 0.01). The control of the patella tilt was correlated with a good functional result (P < 0.01). CONCLUSION: The MPFLr, whether isolated or associated with a TT transfer, provides good long-term clinical and radiological outcomes with a low rate of recurrence. The addition of a TT transfer, when necessary, results in the same good outcomes. This article provides a guide for surgeons evaluating PFI to choose the most appropriate procedure. LEVEL OF EVIDENCE: IV.

Intraprosthetic dislocation of dual mobility total hip arthroplasty: still occurring?

PURPOSE: The objective was to identify predictive factors for intraprosthetic dislocation (IPD) and to understand how improvements in dual mobility cups (DMC) have helped to reduce dramatically the occurrence of this complication. METHODS: DM mobile inserts retrieved from 93 hips were divided into three groups: first-generation DMC with IPD ("firstDMC-IPD"), first-generation DMC with over 15 years of implantation without IPD ("firstDMC-noIPD"), and latest-generation DMC ("newDMC"). The predictive factors for IPD based on clinical, prosthetic, radiological and intraoperative characteristics were analysed by multivariate analysis. The surface of each retrieved mobile insert was analysed using three-dimensional CT scan in order to compare their rim wear. RESULTS: Three predictive factors for IPD were found: a high BMI, a wide rough stem neck and a large cup size. Wear of the firstDMC-noIPD inserts was significantly less than those of firstDMC-IPD inserts and significantly more than those of newDMC inserts. For the firstDMC-IPD inserts, the rim's outer surface wear was significantly greater than the rim's inner surface wear. CONCLUSIONS: IPD is a specific complication related to wear of the DM mobile insert due to failure of the liner's retaining rim, especially from the rim's outer surface. This long-term issue is different to the early traumatic complication, which can happen after an attempt at closed reduction of a DM THA dislocation. Recent modifications in the design and the coating of contemporary DMC and femoral stems, as well as improvements in the mobile insert itself, seem to corroborate our assumptions about the IPD mechanism and contribute to the quasi-disappearance of this complication.