Five to thirteen year results of a cemented dual mobility socket to treat recurrent dislocation.

PURPOSE: Dual mobility (DM) socket has been associated with a low rate of dislocation following both primary and revision total hip arthroplasty (THA). However, little is known about the long-term efficiency of DM in the treatment of THA instability. The purpose of this retrospective study was to evaluate the outcome of a cemented DM socket to treat recurrent dislocation after a minimum of five year follow-up. METHODS: The series included 51 patients with a mean age of 71.3 ± 11.5 (range, 41-98) years presenting with recurrent dislocation (mean 3.3). A single DM socket design was used consisting of a stainless steel outer shell with grooves with a highly polished inner surface articulating with a mobile polyethylene component. The femoral head was captured in the polyethylene component using a snap-fit type mechanism, the latter acting as a large unconstrained head inside the metal cup. RESULTS: At the minimum five year follow-up evaluation, 18 of the 51 patients deceased at a mean of 4.8 ± 2.3 years, three were lost to follow-up at a mean of 1.4 years, seven had been revised at a mean of 4.7 ± 3.1 years (range, 1.5-9.1), and the remaining 23 were still alive and did not have revision at a mean of 8.2 ± 2.4 years (range, 5-13 years). Of the seven revision, three were performed for further episodes of dislocation (at the large bearing for one patient and intra-prosthetic for two patients) after a mean 5.9 ± 2.9 years (range, 2.7-9.1), whereas two were performed for late sepsis and two for aseptic loosening of the acetabular component. Radiographic analysis did not reveal any further loosening on the acetabular side. The survival rate of the cup at ten years, using re-dislocation as the end-point, was 86.1 ± 8.4% (95% confidence interval, 69.7-100%). The survival rate of the cup at ten years, using revision for any reason as the end-point, was 75.2 ± 9.3% (95% confidence interval, 56.9-93.5%). CONCLUSION: A cemented dual mobility cup was able to restore hip stability in 94% of patients presenting with recurrent dislocating hips up to 13-year follow-up with none of the complications associated with constrained devices, as mechanical failure occurred in only 3.9% of the patients of this series. The overall reduced survival using revision for any reason as the end-point at ten years was related to this specific patients population that had various co-morbidities.

Is tibial cut navigation alone sufficient in medial unicompartmental knee arthroplasty? Continuous series of fifty nine procedures.

PURPOSE: Our purpose was to assess medial unicompartmental knee arthroplasty with navigation alone for the tibial cut and limb alignment. We hypothesised that this technique could be used routinely in practice. METHODS: Outcome measures were tibial cut orientation and residual varus. Six-month post-operative radiographs of 59 knees were assessed. RESULTS: Tibial cut orientation was within 2° of planned in 70.2 and 76.3 % of knees in the coronal and sagittal planes, respectively (49.1 % in both), within 4° in 91.2 and 91.5 %, respectively (82.5 % in both). All coronal-plane errors were in varus. Excessive planed tibial slope was at risk of excessive varus of the tibial cut. The hip-knee-ankle angle was ≤179° in 81.4 % and the mechanical axis through Kennedy Zone 2 in 59.3 % of knees. Risk factors for inadequate varus were pre-operative hip-knee-ankle angle >176° and strictly articular varus. CONCLUSIONS: Our results are not as good as previously reported with this technique, but taking into account the factors of failure identified, we could enhance the results.

How can we optimize anterior iliac crest bone harvesting? An anatomical and radiological study.

PURPOSE: Anterior iliac crest bone is a widely used donor site for bone harvesting. It provides an autologous bone graft consisting of cancellous bone that can be packed or cortical bone with greater structural support. Uses include spinal fusion and fracture non-union surgery. Although its use is common, dedicated anatomical and radiological studies analysing graft dimensions and optimal harvesting site in relation to local anatomical landmarks [anterior superior iliac spine (ASIS), anterior iliac tubercle (AIT) and lateral femoral cutaneous nerve (LFCN)] have not been described. METHODS: Twenty-eight female hemipelvises were dissected for this study. The LFCN, ASIS and AIT were identified. Calliper measurements and CT scan analysis were undertaken to determine the optimum positions in obtaining a 5-mm-thickness tricortical graft whilst remaining safe for the LFCN. RESULTS: According to our measurements, the optimal location for harvesting a 5-mm-thick tricortical graft with 35-mm height and 47-mm width is situated anterior to a line passing at the level of the thickest point of the AIT. This thickest point was situated at a mean 67 mm from the centre of the EIAS in our study. CONCLUSION: This anatomical and radiographic study determined the anatomical iliac crest landmarks to avoid neurological injury when taking an optimal 5-mm-width tricortical bone graft.

Should trochanteric fractures in elderly patients be treated by arthroplasty or internal fixation?

Most trochanteric fractures are treated by fixation, most often intramedullary. Nevertheless, the desire to have patients walk as soon as possible and the fear of fixation failure has driven some surgeons to carry out an arthroplasty instead, especially for unstable fractures and/or in patients with severe osteoporosis, in order to avoid the difficult conversion to arthroplasty later on if the fixation fails. The aim of this review was to specify the role, technique and results of performing arthroplasty in this context. In which fractures? Unstable fractures (A2.2, A2.3 and A3), especially in osteoporotic bone, which are the most difficult to reduce and fix, and in cases with associated osteoarthritis. For which patients? Arthroplasty should not be done in patients who have ASA≤3 due to greater blood loss and longer operative time. Since the postoperative Parker score often drops, arthroplasty should not be done in patients having a Parker score<6. What are the technical problems? Arthroplasty must be done by an experienced surgeon because of the lack of anatomical landmarks, although fracture fixation has its own demands (satisfactory reduction, appropriate length and position of cervicocephalic screw). What are the results and complications? Despite several comparative studies (randomized trials, meta-analysis and prospective studies), it is difficult to draw any conclusions. These studies show worse performance of dynamic hip screws relative to intramedullary nails. The complication and revision rates were higher for nails than arthroplasty, but not in every study, while the functional outcomes with nails (with or without immediate weightbearing) were better than those of arthroplasty beyond 6 months. What is the mortality rate? It was lower after nailing in a few studies but was mainly determined by the patient's comorbidities and preoperative Parker score. The best indication for arthroplasty may be self-sufficient patients over 70 years of age who have an unstable fracture with severe osteoporosis. Nevertheless, new studies should be done to compare arthroplasty to nailing with immediate return to weightbearing in patients having the same type of fracture, defined using 3D CT scan. Level of evidence: Expert advice.

Management of fixed flexion contracture in primary total knee arthroplasty: recent systematic review.

INTRODUCTION: This study aimed to systematically review the literature and identify the surgical management strategy for fixed flexion contracture in primary total knee arthroplasty (TKA) surgery, pre-, intra-, and post-operatively. Secondary endpoints were etiologies and factors favoring flexion contracture. MATERIALS AND METHODS: Searches were carried out in November 2023 in several databases (Pubmed, Scopus, Cochrane, and Google Scholar) using the following keywords: "flexion contracture AND TKA", "fixed flexion deformity AND TKA", "posterior capsular release AND TKA", "posterior capsulotomy in TKA", "distal femoral resection AND TKA". Study quality was assessed using the STROBE checklist and the Downs and Black score. Data concerning factors or strategies leading to the development or prevention of flexion contracture after TKA were extracted from the text, figures, and tables of the included references. The effect of each predictive factor on flexion contracture after TKA was recorded. RESULTS: Thirty-one studies were identified to meet the inclusion and exclusion criteria. These studies described a variety of preoperative and intraoperative factors that contribute to the development or correction of postoperative flexion contracture. The only clearly identified predictor of postoperative flexion contracture was preoperative flexion contracture. Intraoperative steps described to correct flexion contracture were: soft-tissue balancing (in posterior and medial compartments), distal femoral resection, flexion of the femoral component, and posterior condylar resection. However, no study has investigated these factors in a global model. DISCUSSION: This review identified various pre-, intra-, and post-operative factors predictive of post-operative flexion contracture. In practice, these factors are likely to interact, and it is therefore crucial to further investigate them in a comprehensive model to develop an algorithm for the management of flexion contracture. LEVEL OF EVIDENCE: IV.

Is hybrid fixation in revision TKA using LCCK prostheses reliable?

INTRODUCTION: The optimal technique for component fixation in revision total knee arthroplasty (rTKA) remains controversial: full cementation (FC) versus hybrid fixation (HF), which involves press-fit stem with cement fixation in the metaphyseal and epiphyseal zones. Previous series have either demonstrated the superiority of one or the other of these techniques or their equivalence. However, few studies have compared these 2 methods for rTKA using the Legacy® Constrained Condylar Knee (LCCK) prosthesis (Zimmer, Warsaw, Indiana, USA). HYPOTHESIS: Our hypothesis was that HF of LCCK components is associated with a higher rate of aseptic loosening (AL) than FC. MATERIALS AND METHODS: This was a single-center, multi-surgeon, retrospective study. Primary revisions between January 2010 and December 2014 were included for all indications. The only exclusion criterion was death without revision before the 5-year follow-up. The primary objective of this study was to compare the survivorship of 2 groups of LCCK components (femoral or tibial), depending on whether their stems had been cemented (HF versus FC), taking AL, revised or not, as the endpoint. The secondary objective was to look for other predictive factors of AL. RESULTS: A total of 75 rTKAs (150 components) were included. The FC group (51 components) had more Anderson Orthopedic Research Institute (AORI) type 2B and type 3 bone defects (BDs) (p<0.001), more reconstructions using trabecular metal (TM) cones (19 FCs and 5 HFs; p<0.001), and bone allografts (p<0.001). At more than 5 years, none of the FC components were loose compared to 10 HF components (9.4%), with 4 of these stems revised. The only significant difference was survivorship without radiographic AL at 9 years (FC=100%; HF=78.6%; p=0.04). The only predictive factor of AL in the HF group was the filling of the diaphyseal canal (p<0.01). The detrimental effect of BD severity (p=0.78) and the protective effect of TM cones were not demonstrated (p=0.21). DISCUSSION: Other series studying revisions using the same type of prosthesis also concluded the superiority of FC, not found for other revision prostheses. Despite this study's limitations (retrospective, multi-surgeon, limited sample size, and limited follow-up), all patient outcomes were known, and the difference in survivorship between the groups was very significant. CONCLUSION: HF has not been proven effective for the LCCK prosthesis. Better diaphyseal filling, wider metaphyseal bone tunnels enabling better cement injections, and stem designs more appropriate for press-fit fixation could improve these results. TM cones are an interesting avenue for further research. LEVEL OF EVIDENCE: III; retrospective comparative study.

Preoperative flexion contracture does not affect outcome in total knee arthroplasty: A case-control study of 2,634 TKAs.

BACKGROUND: One issue in total knee arthroplasty (TKA) is management of preoperative flexion contracture, which may be associated with poor functional outcome. AIM: The aim of this study was to compare functional results in TKA with or without preoperative flexion contracture, treated according to a standardized algorithm of tissue release and bone cut. PATIENTS AND METHOD: A single-center retrospective case-control study was performed on prospectively collected data for the period 1987-2016. Patients with >10̊ flexion contracture were assigned to the "contracture" group and associated to a selected control group at a ratio of 1:4. Clinical analysis used pre and post-operative International Knee Society (IKS) scores. The significance threshold was set at p<0.05. RESULTS: Eight hundred and forty-nine cases and 3,304 controls were included, comprising a total of 2,838 male and 1,315 female participants. Mean preoperative extension deficit was 13̊±6̊ in the contracture group and 1̊±2̊ in controls. Preoperative IKS total and functional scores were significantly poorer in the contracture group (38±18 and 54±20) than in controls (52±16 and 59±19) (p<0.001). Postoperatively, the two groups did not significantly differ in IKS functional score (77±22 vs. 79±21, p=0.143). There were differences in IKS knee score (87±12 vs. 88±13, p=0.006) and maximal flexion (114̊±14̊ vs. 119̊±13̊, p<0.0001) that were statistically, but not clinically, significant. DISCUSSION: A systematic standardized algorithm for surgical treatment of flexion contracture during primary total knee arthroplasty provided clinical outcomes similar to those of patients without preoperative flexion contracture. LEVEL OF EVIDENCE: III; case-control study.

Techniques for filling tibiofemoral bone defects during revision total knee arthroplasty.

There are a variety of options for filling defects during revision total knee arthroplasty: cement with or without screws, structural or morselized allograft, highly porous cones and sleeves, massive bone allograft or megaprostheses. Our goal is to describe the techniques for these procedures and their indications. Any necrotic bone, fibrous tissue or granulomas must be excised, and the bone freshened. The height of the joint line must be restored using trial components stabilized by stems. The defect is the space between the bone and each of the two components. Whether contained or not, it can be evaluated using the AORI classification. Cement alone or supplemented with screws, which is pressurized to penetrate the bone, is now only used in small defects less than 10mm in diameter, especially contained one. It is preferable to use morselized compacted bone graft instead. Augments are used to fill AORI type 2 defects less than 10 mm deep in a condyle. They can also be used to position the femoral component and sometimes the tibial one. For type 2 and 3 defects, bone allografts aim to reconstruct the skeleton. They can be used as trimmed fragments, as described by Engh who did hemispheric reaming to embed a femoral head into the defect. One can also compact or pack morselized bone graft around a stem. These reconstruction procedures are long and difficult. They are being done less and less since porous cones and sleeves were introduced, which are impacted after bone preparation. These sterile components are secured to the stem either mechanically or with cement, saving time. Once in place, bone grows into them. They provide metaphyseal anchoring that helps to reduce the stem's length. When the epiphysis is nearly all gone, the choices are a massive bone allograft or a megaprosthesis, although both have a high risk of infection and mechanical failure. The allograft must be trimmed to restore the height of the joint line and achieve a stable connection with the host bone. A long stem, always cemented into the allograft, is essential. In older patients, a megaprothesis is simpler to use and faster. The femur is better suited to massive reconstruction than the tibia, where coverage must be ensured along with extensor mechanism continuity. LEVEL OF EVIDENCE: V; expert opinion.

Techniques and outcomes of hip abductor reconstruction following tumor resection in adults.

The function of the abductor mechanism (AM) of the hip can be disturbed, or even compromised, following tumor resection in the hip area. The consequences are instability (limping, dislocation), pain and altered walking ability. Several reconstruction techniques can be used for the same AM sacrifice. After defining the AM, this lecture will discuss the best technique for a given type of bone and muscle resection. These reconstruction techniques depend on exactly where the AM was sacrificed. For zone 1 resections of the ilium and/or iliac gluteal insertions, reconstruction is often optional. When muscle from the AM is resected, especially when the gluteal tendon is detached from its trochanteric insertion, isolated reconstruction can be done or reconstruction in combination with a tendon allograft or an allograft and/or tendon transfer from the surrounding area. This sacrifice, whether followed by reconstruction or not, in most cases leads to a good functional outcome, except when a complete musculotendinous unit or the superior gluteal nerve is sacrificed. Isolated resection of the greater trochanter is rare; however, this completely disrupts the continuity of the AM and justifies reconstruction, often using a bone-tendon allograft. Proximal femur resection is the most common scenario. The extent of the trochanteric resection and the gluteal tendon attachments drives the type of prosthesis used. The two most used techniques consist in an allograft sleeve over a long cemented femoral stem (allograft prosthesis composite - APC) or a modular proximal femoral endoprosthesis (megaprosthesis) with a specific AM fixation system (small plate or wire cerclage, resorbable or metal wire, synthetic reattachment tube). These two techniques yield nearly identical long-term functional outcomes with complications specific to each: osteolysis and fracture for APC, failure of tendon reattachment for megaprosthesis. Beyond these technical considerations, one must consider the poor availability of massive bone allografts. This is a highly relevant issue in France, and partially explains the shift to reconstruction with a megaprosthesis. Lastly, we will look at the different clinical and diagnostic tests used to evaluate the function of the AM in an oncology context and the outcomes of the various types of reconstruction.

Development of a dosing-adjustment tool for fluoroquinolones in osteoarticular infections: The Fluo-pop study.

Fluoroquinolones efficacy depend on both the drug exposure and the level of drug resistance of the bacteria responsible for the infection. Specifically for the Staphylococcus species, which is the microorganism mainly involved in osteoarticular infections (OAI), in-vitro data reported that an AUC/MIC ratio above 115 h maximizes drug efficacy. However, data on OAI patients are lacking and a simple approach to access AUCs is still a clinical issue. We conducted a prospective, single-center study in 30 OAI patients hospitalized in the Rennes University Hospital to model ofloxacin pharmacokinetics and to define a limited sampling strategy (LSS) suitable for ofloxacin and levofloxacin treatments. Modeling was conducted with the Monolix software. The final model was externally validated using levofloxacin data. Monte-Carlo simulations were used to evaluate the probability of target attainment (PTA) of different dosing regimens. Two hundred and ninety-seven (297) ofloxacin concentrations were available for the pharmacokinetic modeling. Ofloxacin pharmacokinetics was best described using a bicompartmental model with a first order elimination, and a transit compartment model absorption. CKD-EPI and sex explained half of ofloxacin pharmacokinetic variability. For LSS, the 0, 1 h and 3 h sampling scheme resulted in the best approach both for BID and TID dosages (R2 adjusted = 91.1% and 95.0%, outliers = 4.8% and 5.0%, respectively). PTA allows choosing the best drug and dosage according to various hypotheses. A simple 3-sample protocol (pre-dose, 1 h after intake and 3 h after intake) to estimate ofloxacin and levofloxacin AUC allows optimal drug dosage for the treatment of osteoarticular infections.

The use of a cemented dual mobility socket to treat recurrent dislocation.

BACKGROUND: The treatment of recurrent dislocation after total hip arthroplasty remains challenging. Dual mobility sockets have been associated with a low rate of dislocation but it is not known whether they are useful for treating recurrent dislocation. QUESTIONS/PURPOSES: We therefore asked whether a cemented dual mobility socket would (1) restore hip stability following recurrent dislocation; (2) provide a pain-free and mobile hip; and (3) show durable radiographic fixation. METHODS: We retrospectively reviewed 51 patients treated with a cemented dual mobility socket for recurrent dislocation after total hip arthroplasty between August 2002 and June 2005. The mean age at the time of the index procedure of was 71.3 years. Of the 51 patients, 47 have had complete clinical and radiographic evaluation data at a mean followup of 51.4 months (range, 25-76.3 months). RESULTS: The cemented dual mobility socket restored complete stability of the hip in 45 of the 47 patients (96%). The mean Merle d'Aubigné hip score was 16 ± 2 at the latest followup. Radiographic analysis revealed no or radiolucent lines less than 1 mm thick located in a single acetabular zone in 43 of 47 hips (91.5%). The cumulative survival rate of the acetabular component at 72 months using revision for dislocation and/or mechanical failure as the end point was 96% ± 4% (95% confidence interval, 90%-100%). CONCLUSIONS: A cemented dual mobility socket was able to restore hip stability in 96% of recurrent dislocating hips. However, longer-term followup is needed to ensure that dislocation and loosening rates will not increase.

Tantalum implants for posterior lumbar interbody fusion: A safe method at medium-term follow-up?

INTRODUCTION: Intervertebral implants increase stability and improve results in lumbar interbody fusion (LIF). The aim of the present study was to assess clinical and radiological results of posterior lumbar interbody fusion (PLIF) using a tantalum intervertebral implant without associated interbody bone graft. MATERIEL AND METHODS: A single-center retrospective study included 52 cases of single-level PLIF, using 2 tantalum intervertebral cages, without interbody bone graft: 42 for degenerative disc disease, 10 for isthmic spondylolisthesis. Minimum follow-up was 2 years. Clinical assessment used a visual analog (pain) scale (VAS), the Oswestry Disability Index (ODI) and the Roland Morris (RM) scale. Tantalum osseointegration and intersegment mobility were assessed on static and dynamic X-ray. RESULTS: Forty-nine patients were included, with a mean 55months' follow-up (range, 25-74months). VAS, ODI and RM scores showed significant improvement at last-follow-up, at 4, 30 and 28 points respectively. There was no mechanical failure on static X-ray; all patients had less than 5° mobility on dynamic X-ray at last follow-up. DISCUSSION: PLIF with tantalum intervertebral implant without interbody bone graft provided satisfactory clinical and radiological results at medium-term follow-up. The present findings showed reliable primary stability and osseointegration of the tantalum implant. LEVEL OF EVIDENCE: IV.

Role of MRI in the assessment of interbody fusion with tantalum intervertebral implant.

INTRODUCTION: Radiologic assessment of interbody fusion (IF) is controversial; thin-slice CT is the present gold standard despite artifacts due to the metal implant that hinder interpretation. The present study aimed to assess the contribution of MRI in IF assessment after instrumented posterior lumbar interbody fusion (PLIF) using tantalum intervertebral implants. The study hypothesis was that fusion following PLIF can be assessed on MRI. MATERIALS AND METHOD: A single-center retrospective study included 52 single-level PLIF procedures (42 for degenerative disc disease and 10 for isthmic spondylolisthesis) using 2 tantalum intervertebral cages without interbody bone graft. Fusion was assessed at 1 year on static and dynamic X-ray and on MRI with a dedicated protocol. Two senior osteoarticular radiologists screened frontal and sagittal MRI slices for continuous cancellous interbody bridges. Consolidation was considered acquired (grade I) in case of continuous bridges on at least 2 successive frontal or sagittal slices, possible (grade II) in case of continuous bridge on just 1 slice, or absent (grade III) in case of no or discontinuous bridge. RESULTS: Forty-eight patients were included, with a mean 55 months' follow-up (range, 25-74 months). There were no hardware failures. Intervertebral mobility on dynamic X-ray was systematically less than 5°. Fusion on MRI was grade I in 71% of cases, grade II in 8% and grade III in 21%. Interobserver agreement was 100% on X-ray and 81% on MRI, with kappa coefficient=0.56 (range, 0.35-0.77). DISCUSSION: Tantalum implants without bone autograft enabled satisfactory standard radiographic study. MRI provided imperfect assessment of fusion, being contributive only in case of positive findings (71% in the present study); when no bridge is detected on MRI, no conclusion can be drawn. Progress in CT to reduce artifacts may improve fusion assessment, unless bone integration on both sides of the implant is considered to be sufficient for interbody continuity, without a continuous bone bridge between endplates being a requirement. LEVEL OF EVIDENCE: IV.

Extraction of total knee arthroplasty intramedullary stem extensions.

Intramedullary stem extensions will need to be extracted during total knee arthroplasty (TKA) revisions, especially repeated ones. These stems have various designs and lengths, can be straight or offset, cemented (partially or totally) or cementless, smooth or rough. This diversity adds to the difficult of extracting them, which the surgeon must anticipate before starting the revision procedure. Porous metaphyseal metal components (cones, sleeves) are being used increasingly during revision TKA. They pose specific extraction challenges and complicate the extraction of the stems with which they are often associated. The maneuvers used during extraction have a direct impact on the subsequent joint reconstruction methods. These procedures are always long and difficult, with an increased risk of bone-related complications (perforation, fracture) or infection. They must always be carried out at specialized centers by experienced surgeons. The reasons for re-revision are the same as those for TKA revision, mainly aseptic loosening, instability and infection-only the latter requires that all components be removed. The local conditions are often unfavorable: epiphyseal-metaphyseal bone defect, thin cortices, osteoporosis, and in some cases, stiffness. The type of implant to extract and its characteristics must be identified beforehand in case special instruments are needed. An imaging workup is done to specify the relationship of the stem with bone, quality of its fixation, bone lesions and gaps between stem and bone, knowing that extraction is harder when the gaps are smaller. A combination of extended radiolucent lines, purely metaphyseal fixation, and a thin smooth stem may mean that intramedullary extraction is feasible. The extensor mechanism must be released to achieve sufficient exposure. If a tibial tubercle osteotomy is needed, it must be sized to match the extraction. After disassembly of femoral and tibial components-which can be challenging-the epiphyseal components must be released. High performance instruments for cement extraction and metal cutting are essential. Other than simple cases (loosened or partially fixed implants), intramedullary extraction can be dangerous especially when the stem extension is well-fixed, whether cemented or not. A diaphyseal window may be sufficient, but in most cases, an extended osteotomy is needed. This includes detaching the tibial tubercle at the tibia. At the femur, this may require an anterior midline window, an anterior extended ostéotomy or an anterolateral oblique distal femoral osteotomy with fibrous hinge. The extraction of metaphyseal porous components is difficult. Their connection with the bone must be broken - which can be long and risky - before the associated stem is removed. While it is easier to extract when the stem can be removed first, it is not always feasible. Reconstruction depends intimately on the methods used to extract the existing implants. Any diaphyseal discontinuity must be bridged (long stem or plate). The extent of the resulting bone defect after extraction drives the revision methods, which are simplified by using porous metaphyseal metal components and shorter stems when possible.

Acetabular reconstruction using porous metallic material in complex revision total hip arthroplasty: A systematic review.

Bone defects during acetabular revision of total hip arthroplasty raise a problem of primary fixation and of durable reconstruction. Bone graft with direct cemented fixation or in a reinforcement cage was long considered to be the gold standard; however, failures were reported after 10 years' follow-up, especially in segmental defect of the roof or pelvic discontinuity. In such cases, metallic materials were proposed, to ensure primary fixation by a roughness effect with added screws, and especially to avoid failure due to bone resorption in the medium term. We report a systematic literature analysis, addressing the following questions: (1) What materials are available and can be used with dual mobility (DM) designs? Apart from Trabecular Metal™ (TM), in which a DM cup can be cemented for sizes≥56mm, 4 other porous metals are available (Tritanium™, Trabecular Titanium™, Conceloc™, Regenerex™ and Gription™) although only the first 3 can be associated to DM. (2) Can the cost of these materials be estimated and compared to allograft with reinforcement cage? Considering simply the cost of the implant itself, compared to reconstruction by graft+cage+cemented cup (€2100), TM incurs an extra cost of €534, but with €1434 not covered by the French healthcare insurance. The cost of custom implants (apart from hemi-pelvis) ranges between €4200 and €8500, with only €4749 cover. (3) Do metallic materials ensure better survival than allograft+cage, according to severity of bone loss? Metallic reconstruction is claimed (with a low level of evidence) to reduce the risk of iterative loosening, but with a higher rate of dislocation, probably due to the lack of DM in many series. (4) What are the advantages and drawbacks of modular and custom metallic reconstructions? Modular reconstructions do not require 3D preoperative planning, but incur the risks of complications inherent to modularity. Custom implants can deal with more extensive defects, but require 5 to 8 weeks' production and are difficult to implant for the larger ones and/or when revision is limited to the acetabulum. (5) In what indications are these materials irreplaceable? Prior failure of allograft+cage in Paprosky type III defect with or without pelvic discontinuity shows the greatest benefit from metallic reconstruction, conditional on certain technical tricks. Only reconstructions using TM have more than 10 years' follow-up; other materials will need close monitoring. Failures in allograft with reinforcement cages occurred after about 10 years, and TM will need longer follow-up to prove its effectiveness. The high risk of dislocation should enable DM to be used, especially for small-diameter metallic reconstructions.

Risk factors for dislocation after revision total hip arthroplasty with a dual-mobility cup. Matched case-control study (16 cases vs. 48 controls).

BACKGROUND: Reports of high dislocation rates after revision total hip arthroplasty (THA) have encouraged the widespread use of dual-mobility cups. Dislocation has been less common but not fully abolished with dual-mobility cups, and its causes have remained unidentified. The objectives of this retrospective matched case-control study were: 1) to identify risk factors for dislocation, 2) and to assess dislocation outcomes. HYPOTHESIS: The causes of dislocation after revision THA with a dual-mobility cup can be identified. MATERIAL AND METHOD: Among 653 consecutive patients identified retrospectively as having undergone revision THA with a dual-mobility cup (Medial Cup, Aston, Saint-Étienne, France) between January 2007 and December 2017, 16 (2.45%) subsequently experienced dislocation, after a mean of 3.6 months (range, 0.9-19 months). For each of these 16 patients, we collected the main patient characteristics (age, sex, body mass index [BMI], ASA score, and reason for the initial arthroplasty procedure), local history (number of previous surgical procedures, reason for revision, femoral and acetabular bony defects classified according to Paprosky, and status of the abductor apparatus), and characteristics of the revision (approach, diameters of the cup and femoral head, cup inclination, femoral offset, lower limb length, and implant anteversion). Controls were patients without dislocation after revision dual-mobility THA. Each of the 16 patients was matched to 3 controls on age (±10 years), sex, year of revision, and whether revision was only acetabular or bipolar. Univariate and multivariate analyses were done to compare the cases and controls, and dislocation outcomes in the cases were evaluated. RESULTS: By univariate analyses, factors associated with dislocation were BMI>30 (cases, 37.5%; controls, 10.4%; p=0.02), larger number of previous surgical procedures on the same hip (cases, 2.8; controls, 1.8; p=0.004), larger number of arthroplasties (cases, 2.3; controls, 1.5; p=0.004), history of instability (cases, 31% with chronic dislocation and 13% with recurrent dislocation; controls, 6.25% and 2.1%, respectively; p=0.004), and compromised abductor apparatus (cases, 56.25%; controls, 14.6%; p=0.002). Independent risk factors for dislocation identified by multivariate analysis were instability (odds ratio [OR], 14.5; 95% confidence interval [95%CI], 1.5-149.9) and, most importantly, abductor apparatus compromise (OR, 43.1; 95%CI, 3.18-586.3). Of the 16 cases, 1 was lost to follow-up, 1 had contra-indications to anaesthesia, 1 died after several dislocation episodes, and 1 died 3 months after surgical reduction. In 5 cases, there was a single dislocation episode. Further surgery was performed in 8 cases (surgical reduction, n=1; constrained cup, n=3; trochanteric internal fixation, n=1; exchange of the dual-mobility cup, n=2, including 1 with subsequent dislocation episodes; and femoral component exchange followed by a retentive cup due to further dislocation episodes, n=1). CONCLUSION: Risk factors for dislocation consisted of a history of instability and, most importantly, abductor apparatus compromise. A constrained cup should be considererd in patients with impaired abductor apparatus. No further dislocations occurred after reduction of the first episode in 31.25% of cases. Recurrent dislocation should prompt measures to correct impaired abductor apparatus whenever possible, as well as correction of any component malposition. Whether a retentive cup should be implanted routinely remains unclear. LEVEL OF EVIDENCE: III, matched case-control study.

Inability of 99mTc-ciprofloxacin scintigraphy to discriminate between septic and sterile osteoarticular diseases.

UNLABELLED: Ciprofloxacin labeled with (99m)Tc specifically binds to various bacteria. Thus, it potentially constitutes a specific marker allowing discrimination between septic arthritis/osteomyelitis and aseptic osteoarticular diseases. The aim of this prospective study was to evaluate such properties in patients with skeletal diseases. METHODS: We prospectively investigated 2 groups of patients: patients with suspected osteoarticular infections (G1, n = 16) and a control group of patients with a presentation of osteoarticular diseases and no sign suggestive of infection (G2, n = 11). All had clinical, biologic, and radiologic evaluations and had 1-, 4-, and 24-h images from (99m)Tc-ciprofloxacin scintigraphy (370 MBq) before planned biopsy or surgery. For 23 patients, the scintigraphic results were compared with histologic and bacteriologic analyses of biopsy tissue samples; for 4 patients, the scintigraphic results were compared with the findings from 23 +/- 5 mo of follow-up. RESULTS: In G1, (99m)Tc-ciprofloxacin findings were true-positive in all 11 infected sites, true-negative in 2 cases, and false-positive in 3. In G2, (99m)Tc-ciprofloxacin was true-negative in 4 cases and false-positive in 7. Neither the location of (99m)Tc-ciprofloxacin activity nor its intensity or kinetics between 1, 4, and 24 h allowed discrimination between infection and aseptic diseases (sterile loosened joint replacement, pseudoarthrosis, or arthrosis). Sensitivity, specificity, and accuracy were 100%, 37.5%, and 63%. CONCLUSION: (99m)Tc-Ciprofloxacin scintigraphy showed good sensitivity and a high negative predictive value for the detection of bone and joint infection, but it did not discriminate between infected and aseptic osteoarticular diseases in symptomatic patients referred for surgery.

Lumboradiculopathy due to epidural varices: two case reports and a review of the literature.

Lumbar radicular pain caused by epidural varices is rare. Its incidence is evaluated at 4.5% of operations for disc herniation. We report 2 cases which were only diagnosed during surgery for a herniated disk as is usually observed in the literature. The mechanism behind radicular pain is not fully understood. It may be compression by the varix itself but it may also be secondary to diffculty in venous return. Several anatomical types are described: thrombosed varix (type 1), non thrombosed varix (type 2), localized hematoma (type 3). Our 2 cases corresponded to type 2. The diagnosis can established by MRI at the pre-operative stage. The images vary according to the anatomical type and the age of the lesions. Treatment is by surgery.

Anatomical study of the lateral femoral cutaneous nerve with special reference to minimally invasive anterior approach for total hip replacement.

BACKGROUND: Lesion of the lateral femoral cutaneous nerve (LFCN) represents the main complication during minimally invasive anterior approach dissection to the hip joint. The aim of this anatomical study was to describe the different presentation features of the LFCN at the thigh and particularly to determine the potential location of damage during minimally invasive anterior approach for total hip replacement. METHODS: The LFCN was dissected bilaterally at the thigh under the inguinal ligament in 17 formalin-preserved cadavers. Branching patterns of the nerve were recorded and distances from the LFCN to the anterior superior iliac spine (ASIS) and the anterior margin of the tensor fascia lata (TFL) were measured to clarify skin incision positioning during minimally invasive anterior approach for total hip replacement. RESULTS: The LFCN divided proximal to the inguinal ligament in 13 cases and distal to it in 21 cases. In the distal group the mean distance from the ASIS to the nerve division was 34.5 mm (10-72 mm). The gluteal branch crossed the anterior margin of the TFL 44.5 mm (24-92 mm) distally to the ASIS. In 18 cases the femoral branch did not cross the TFL and was located in the intermuscular space between TFL and sartorius. In the remaining 16 cases, this branch crossed the anterior margin of the TFL 46 mm (27-92 mm) distally to the ASIS. During minimally invasive anterior approach along the anterior border of the TFL, the LFCN was found to be potentially at risk between 27 and 92 mm below the ASIS. We used those informations to describe a map of "danger zones" for the LFCN or its two main branches. CONCLUSION: According to this study, numerous anatomical variations of the LFCN at the thigh should be considered when performing anterior approach to the hip joint. Different mechanisms of injury during surgery should be considered especially during minimally invasive total hip replacement, such as section of the gluteal or the femoral branch where it crosses the anterior margin of the TFL or stretching of the femoral branch due to retractors positioned into the intermuscular space between sartorius and TFL. According to the map of "danger zones" reported, the author policy consists of positioning the skin incision as lateral and distal to the ASIS as possible.