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.

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.

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.

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.

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.

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.

Under-corrected knees do not fail more than aligned knees at 8 years in fixed severe valgus total knee replacement.

PURPOSES: A fixed severe valgus knee is a surgical challenge. A safe post-operative Hip-Knee-Ankle angle (HKA) range of 180° ± 4 was recommended, but recent studies mentioned equal results from outliers of this range. Nevertheless, no distinction was made between varus and valgus knees, as well as over-corrected or under-corrected knees. Did post-operative nonaligned total knee replacements (TKR) from fixed severe valgus knees behave differently from the properly aligned population? Did over-corrected knees behave differently from under-corrected knees? METHODS: Through a multi-center retrospective cohort study, we provided 557 knees of at least 10° of minimal pre-operative valgus; in this population 75 presented a post-operative Hip-Knee-Ankle angle (HKA) outside of the 180° ± 4 range; 23 of them had at least 5° of varus; 52 of them had at least 5° of valgus. Median pre-operative HKA of the entire cohort was 194° (range 190-198). Median follow-up was 8 years (range 5-11); Knee Society Score (KSS) results, HKA, Femoral and Tibial Mechanical Angles (FMA, TMA) and complication rates were obtained. The outlier group (HKA ≤ 175 or ≥ 185) was compared to the control group (HKA 180 ± 4); over-corrected (HKA ≤ 175) and under-corrected (HKA ≥ 185) sub-groups were individually tested against the control group. RESULTS: The outlier group had a lower Final Knee Score than the aligned group (p = 0.023). In the over-corrected sub-group, median post-operative FMA was 88° (SD 4°) and median TMA was 87° (SD 4°). The complication rate was higher (p = 0.019). Knee (p = 0.018), Function (p = 0.034) and Final Knee Scores (p = 0.03) were statistically lower than in the control group. In the under-corrected sub-group, mean post-operative FMA was 93° (SD 2°) and mean TMA was 91° (SD 2°). The complication rate was lower (p = 0.019) and there was no difference with the control group concerning KSS. CONCLUSIONS: In case of pre-operative fixed severe valgus knee, one should avoid over-correcting HKA angle and especially the TMA. Over-correction of a severe preoperative valgus in a post-operative varus was prejudicial for TKA survival. Keeping a severe valgus knee in low valgus to avoid using a more constrained implant and/or ligament releases will not decrease the 5-10 year implant survival and functional scores. LEVEL OF EVIDENCE: Level IV-Case series.

Is Cross-Linked Polyethylene an Improvement Over Conventional Ultra-High Molecular Weight Polyethylene in Total Knee Arthroplasty?

BACKGROUND: Reducing polyethylene (PE) wear by increasing the cross-linking encouraged surgeons to hope for increased total knee arthroplasty (TKA) survival rates. Different methods of manufacturing cross-linked polyethylene (XLPE) were introduced, following promising in vitro results. Is there a measurable effect of cross-linking on TKA survival? METHODS: A registry study was conducted, focusing on fixed tibial inserts in primary TKA. Conventional PE represented 87% of the liners, 10% were cross-linked and 2% were antioxidant PE. Sixty-four percent of the liners were posterior-stabilized (PS). Survival of the different PE groups and survival of the main XLPE available were successively compared. We also looked for differences in the same brand implant groups with regard to PE type, as well as differences between cruciate retaining and PS knees. RESULTS: No differences were found when looking at survival for any cause or for aseptic loosening only (P = .96). When comparing the XLPE available, X3 was found to have a better survival than Prolong or Smith & Nephew XLPE (P = .036). When the same implants and X3 or conventional PE were used, no difference could reach a statistical significance. With Zimmer LPS Flex, Prolong XLPE was even associated with a lower survival compared with conventional PE. On Stryker implants, only the Cox regression model allowed highlighting a difference between X3 XLPE and conventional PE, only in PS knees. CONCLUSION: Increasing the cross-linking seems to only have a low effect, if any, on knee arthroplasty survival. Differences between brands could be found; the manufacturing process could play a role.

Ten-Year Clinical and Radiological Outcomes of 100 Total Hip Arthroplasty Cases with a Modern Cementless Dual Mobility Cup.

INTRODUCTION: The original cementless Sunfit® dual mobility cup (SERF, Décines, France) exhibited limited osseointegration due to its hydroxyapatite and alumina coating. We hypothesized that replacement of the alumina with plasma-sprayed titanium + hydroxyapatite and improvement of the external geometry (Sunfit TH®) would not increase the risk of aseptic loosening. The primary goal of this study was to determine the survivorship and clinical and radiological outcomes among patients with the Sunfit TH® implant. MATERIAL AND METHODS: This was a single-center, prospective study of the first 100 consecutive total hip arthroplasty (THA) cases performed using the combination of a press-fit Sunfit TH® dual mobility cup and a cementless straight stem. All of the cases were primary THA and the posterolateral approach was used. The patients underwent regular clinical and radiological monitoring. Radiological measurements were carried out using OsiriX® software (Pixmeo, Geneva, Switzerland). RESULTS: As of the final follow-up, 19 patients had died and 4 could not be contacted. Of the remaining patients, there were zero cases of aseptic loosening, dislocation or intraprosthetic dislocation (IPD). The survivorship was 100% at 10.03 years of follow-up. No significant implant migration was measured on radiographs. CONCLUSION: The excellent long-term outcomes with the Sunfit TH® cup are likely due to the use of plasma-sprayed titanium + hydroxyapatite in the coating and the addition of supplementary ridges and grooves to the outside of the cup. The absence of aseptic loosening, dislocation and IPD further confirms the high stability and good survivorship that can be achieved with these implants. We believe dual mobility cups should be used in patients above 60 years of age and in those below 60 years of age with a high risk of postoperative instability.

Anterolateral Ligament of the Knee: What we Know About its Anatomy, Histology, Biomechanical Properties and Function.

To better control anterolateral rotational instability (ALRI) after anterior cruciate ligament reconstruction (ACLR), many recent studies have examined the anterolateral ligament (ALL). Although some inconsistencies have been reported, anatomic studies demonstrated that the ALL runs on the lateral side of the knee from the femoral lateral epicondyle area to the proximal tibia, between Gerdy's tubercle and the fibula head. Histologic research has characterized the ALL structure, which is more than a simple capsular thickening; it shows a dense collagen core, typical bony insertions and mechanoreceptor function. An analysis of biomechanical properties suggests that the ALL is weaker than other knee ligaments. While its contributions to tibial anterior translation control and to a high grade on the Pivot-Shift test are still unclear, there is a consensus that the ALL controls tibial internal rotation. Further research will be needed to clarify the significance of ALL injuries and to gauge the value of combined ACL and ALL reconstructions.

Long-term wear of dual mobility total hip replacement cups: explant study.

PURPOSE: Dual mobility THA implantations are increasing. THA survival of more than 15 years is considered long-term survival based on the Charnley prosthesis, which has a median wear rate of 39 to 98 mm3/year. What is the median wear rate of dual mobility THA cups and its repartition on the liner volume? What are the factors influencing dual mobility wear? METHODS: Thirty-five explants were analysed. The liners were entirely mapped with a fully automatic stripe light scanner that uses green LED light. RESULTS: The liners had a median wear rate of 38 mm3/year. The distribution of the wear between the two bearings varied greatly. No factor was found influencing wear volumes. CONCLUSIONS: The median annual wear of dual mobility liners is at least as low as the wear of cemented polyethylene liners and lower than equivalent cementless liners. The two articulations of the dual mobility THA do not cause more wear. LEVEL OF EVIDENCE: Level IV - case series.

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

The published online version contains mistake in the author list for the author name "Di Iorio Alexandre" was incorrectly presented.

Bousquet dual mobility socket for patient under fifty years old. More than twenty year follow-up of one hundred and thirty one hips.

PURPOSE: The aim of this study was to analyze dual mobility cup survival rate on young patients under 50 years old at more than 20 years of follow up. METHODS: One hundred thirty seven hips with a first generation of dual mobility Bousquet cup (Serf) were included. The mean age at the time of the surgery was 41 years and the mean follow-up was 21.9 years. RESULTS: Twenty year follow-up cup survival rate was 77%. No dislocation occurred, 44 hips were revised (including 21 cup aseptic loosenings isolated, 15 Intra Prosthetic Dislocations), seven hips were lost to follow-up, 11 patients died, and 75 hips were still in situ. CONCLUSION: First generation dual mobility cup survival on young patient was comparable with literature results. The main complications, cup aseptic loosening and intra prosthetic dislocation, were wear-related. With improvements of the defects of first generation dual mobility, we might expect an even better survival rate with contemporary DM cups.

Results of primary total hip replacement with first generation Bousquet dual mobility socket with more than twenty five years follow up. About a series of two hundred and twelve hips.

PURPOSE: The aim of our study was to evaluate long-term survival and dislocation rate of this concept. METHODS: It was a retrospective study, on 212 hips using a Bousquet dual mobility Novae® tripodal socket (SERF). Mean follow-up was 25.3 years (95 to 372 months). Mean age at the time of the surgery was 53 years. RESULTS: Pre-operative mean Harris and PMA scores were respectively 54.14 and 11.2. Their respective last follow-up counterparts were 83.6 and 16.9; 25 year follow-up cup survival rate was 90.6%. No dislocation occurred, 45 hips were revised (including 17 cup aseptic loosenings, ten intra prosthetic dislocations, nine liner changes, seven stem failures, two sepsis). CONCLUSION: Dual mobility socket global long term survival rate was comparable to similar cemented or uncemented series. The absence of dislocations proved the interest of dual mobility concept in hip stability. Implant improvements might widen DM socket indication.

The linear penetration rate is not relevant for evaluating wear of dual mobility cups: an explant study.

PURPOSE: The linear penetration rate (LPR) has been used to estimate volumetric wear ever since metal-on-polyethylene bearings were first introduced. Annual volumetric wear and osteolysis are interrelated. The use of dual mobility cups has increased; however, the presence of two bearings needs paraclinical monitoring of wear to anticipate potential wear-related complications. Is LPR correlated to volumetric wear? METHODS: Ninety-eight dual mobility liner retrievals were mapped in three-dimensions (3D) with a fully automatic stripe light scanner. Martell's method was applied to 3D maps of the explants to determine how much the centres of the inner and outer bearings had shifted in the three planes, and in particular, penetration of the femoral head in the "z" axis. The total, inner and outer wear volumes were then compared to the shift in the centres of rotation (COR) and the pre-operative X-rays. RESULTS: There was no relationship between wear and head penetration into the liner. There was a statistically significant relationship between the 3D centre of rotation shift and inner wear or total wear. Wear was multidirectional. CONCLUSIONS: LPR is ineffective for estimating wear of dual mobility inserts, since its wear not two-dimensional. In the future, a 3D imaging method with very thin slices could be used to monitor the wear of dual mobility inserts by measuring the shift in the centres of rotation, once artifacts are overcome.

Understanding wear in dual mobility total hip replacement: first generation explant wear patterns.

PURPOSE: Dual mobility was introduced by Pr. G. Bousquet to improve the dislocation risk of total hip arthroplasty (THR). The wear mechanisms of this implant remain to be understood. Could enhanced explant wear analysis explain liner wear behaviour? METHODS: Sixty-six explanted liners were selected. Non-destructive 3D scanning and heat colour treatment allowed reporting wear patterns on both convex and concave sides of the liners. RESULTS: For many liners, liner convexity wear was found to be homogeneous, and linked to a longer implantation time. A few liners had signs of blocking of the convexity, leading to excessive internal damage. Intra prosthetic dislocations were found to only have internal circular wear without liner penetration. CONCLUSION: Heat colour treatment showed its effectiveness for highlighting wear patterns. Optimal convexity mobility seemed to be leading to a longer implantation time, with decreased contact stresses on concavity. The retentive rim should have a distinct wear analysis.

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.

Perioperative Patient Blood Management (excluding obstetrics): Guidelines from the French National Authority for Health.

The French National Authority for Health (HAS) recently issued guidelines for patient blood management (PBM) in surgical procedures. These recommendations are based on three usual pillars of PBM: optimizing red cell mass, minimizing blood loss and optimizing anemia tolerance. In the preoperative period, these guidelines recommend detecting anemia and iron deficiency and taking corrective measures well in advance of surgery, when possible, in case of surgery with moderate to high bleeding risk or known preoperative anemia. In the intraoperative period, the use of tranexamic acid and some surgical techniques are recommended to limit bleeding in case of high bleeding risk or in case of hemorrhage, and the use of cell salvage is recommended in some surgeries with a major risk of transfusion. In the postoperative period, the limitation of blood samples is recommended but the monitoring of postoperative anemia must be carried out and may lead to corrective measures (intravenous iron in particular) or more precise diagnostic assessment of this anemia. A "restrictive" transfusion threshold considering comorbidities and, most importantly, the tolerance of the patient is recommended postoperatively. The implementation of a strategy and a program for patient blood management is recommended throughout the perioperative period in healthcare establishments in order to reduce blood transfusion and length of stay. This article presents an English translation of the HAS recommendations and a summary of the rationale underlying these recommendations.

Intraprosthetic dislocation: a specific complication of the dual-mobility system.

BACKGROUND: The dual-mobility concept was proposed as an alternative to prevent postoperative dislocation events. However, intraprosthetic dislocation (IPD) is a troublesome and specific complication induced by the loss of the polyethylene retentive rim and escape of the femoral head from the polyethylene liner. The factors associated with IPD are unknown as only isolated cases have been reported and do not provide a clear understanding of the mechanisms of failure. QUESTIONS/PURPOSES: We therefore (1) identified features related to different types of IPD and (2) determined factors related to the timing of IPD. METHODS: We identified 81 cases (80 patients) with IPD from among 1960 primary THAs performed between January 1985 and December 1998. To classify the types of IPD we considered perioperative (presence of arthrofibrosis, cup loosening, and type of liner wear) and radiographic (radiographic cup loosening or migration, and ossification) features. RESULTS: We identified three types of IPD with the following causal mechanisms: Type 1 was pure IPD without arthrofibrosis and without cup loosening (n = 26), Type 2 was IPD secondary to blocking of the liner (n = 41), and Type 3 was IPD associated with a cup loosening (n = 14). The mean times of onset were, 11, 8, and 9 years after THA, respectively. We found no difference according to the stem design regarding timing of the IPD. CONCLUSIONS: This new IPD classification allows clinicians to anticipate the possible conditions they will encounter with revision surgery and plan surgery (cup removal, liner exchange, synovectomy). The implant characteristics and this new classification accounted for the differences in the timing of occurrence. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.