A new ex vivo human model of osteoarthritis cartilage calcification.

OBJECTIVE: Cartilage pathologic calcification is a hallmark of osteoarthritis (OA). Here, we aimed to describe a new ex vivo human model to study the progression of cartilage calcification. METHOD: Cartilage explants (n = 11), as well as primary chondrocytes (n = 3), were obtained from OA patients undergoing knee replacement. Explants and chondrocytes were cultured in control (NT) or calcification (CM) medium (supplemented with ascorbic acid and ß-glycerophosphate). Calcification was evaluated by micro-CT scan at day 0 and 21 in explants, and by Alizarin red staining in chondrocyte monolayers. Raman spectrometry allowed characterization of the crystal type. Interleukin-6 (IL-6) secretion in explant and cell supernatants was measured by ELISA. Finally, matrix degradation was evaluated by Safranin-O staining of explant sections and by glycosaminoglycans (GAG) release in supernatants. RESULTS: Micro-CT scan showed calcifications in all explants at baseline (day 0), which in the CM group increased significantly in number and size after 21 days compared with the NT group. Raman spectrometry revealed that crystals were exclusively basic calcium phosphate crystals (carbonated hydroxyapatite) both in NT and CM. IL-6 secretion was significantly increased in calcifying conditions. Finally, CM significantly increased cartilage catabolism as assessed by decreased Safranin-O staining of tissue explants and increased GAG release in supernatants. CM effects (enhanced calcification, IL-6 secretion and proteoglycans turn-over) were recapitulated in vitro in OA chondrocytes. CONCLUSIONS: We have described a new ex vivo human model of cartilage calcification that can summurize the triad of events seen during osteoarthritis progression, i.e. calcification, inflammation, and cartilage degradation. This model will allow the identification of new anti-calcification compounds.

The relationship between bone strain index, bone mass, microarchitecture and mechanical behavior in human vertebrae: an ex vivo study.

The aim of this study was to determine whether the Bone Strain Index (BSI), a recent DXA-based bone index, is related to bone mechanical behavior, microarchitecture and finally, to determine whether BSI improves the prediction of bone strength and the predictive role of BMD in clinical practice. PURPOSE: Bone Strain Index (BSI) is a new DXA-based bone index that represents the finite element analysis of the bone deformation under load. The current study aimed to assess whether the BSI is associated with 3D microarchitecture and the mechanical behavior of human lumbar vertebrae. METHODS: Lumbar vertebrae (L3) were harvested fresh from 31 human donors. The anteroposterior BMC (g) and aBMD (g/cm2) of the vertebral body were measured using DXA, and then the BSI was automatically derived. The trabecular bone volume (Tb.BV/TV), trabecular thickness (Tb.Th), degree of anisotropy (DA), and structure model index (SMI) were measured using µCT with a 35-µm isotropic voxel size. Quasi-static uniaxial compressive testing was performed on L3 vertebral bodies under displacement control to assess failure load and stiffness. RESULTS: The BSI was significantly correlated with failure load and stiffness (r = -0.60 and -0.59; p < 0.0001), aBMD and BMC (r = -0.93 and -0.86; p < 0.0001); Tb.BV/TV and SMI (r = -0.58 and 0.51; p = 0.001 and 0.004 respectively). After adjustment for aBMD, the association between BSI and stiffness, BSI and SMI remained significant (r = -0.51; p = 0.004 and r = -0.39; p = 0.03 respectively, partial correlations) and the relation between BSI and failure load was close to significance (r = -0.35; p = 0.06). CONCLUSION: The BSI was significantly correlated with the microarchitecture and mechanical behavior of L3 vertebrae, and these associations remained statistically significant regardless of aBMD.

Impact of spinal versus general anaesthesia on perioperative obstructive sleep apnoea severity in patients undergoing hip arthroplasty: a post hoc analysis of two randomised controlled trials.

BACKGROUND: Recommendations suggest favouring regional over general anaesthesia to reduce impact on postoperative sleep apnoea severity, but there is currently no evidence to support this. We compared the impact of general vs spinal anaesthesia on postoperative sleep apnoea severity and assessed the evolution of sleep apnoea severity up to the third postoperative night. METHODS: This post hoc analysis used pooled data from two previous randomised controlled trials in patients undergoing total hip arthroplasty under general or spinal anaesthesia (n=96), without performing a preliminary power analysis. All participants underwent respiratory polygraphy before surgery and on the first and third postoperative nights. The primary outcomes were the supine apnoea-hypopnea index on the first postoperative night and the evolution of the supine apnoea-hypopnea index up to the third postoperative night. Secondary outcomes included the oxygen desaturation index on the first and third postoperative nights. RESULTS: In the general and spinal anaesthesia groups, mean (95% confidence interval) values for the supine apnoea-hypopnoea index on the first postoperative night were 20 (16-25) and 21 (16-26) events h-1 (P=0.82), respectively; corresponding values on the third postoperative night were 34 (22-45) and 35 (20-49) events h-1 (P=0.91). The generalised estimating equations model showed a significant time effect. Secondary outcomes were similar in the two groups. CONCLUSIONS: Use of spinal anaesthesia compared with general anaesthesia was not associated with a reduction in postoperative sleep apnoea severity, which was worse on the third postoperative night. CLINICAL TRIAL REGISTRATION: NCT02717780 and NCT02566226.

The use of dual mobility cups in revision total hip arthroplasty for failed large head metal-on-metal bearings.

PURPOSE: Revision of failed large head metal-on-metal (MoM) total hip arthroplasty (THA) is a challenging procedure particularly to reconstruct acetabular bone defect due to osteolysis and to achieve hip stability due to soft tissue damages, both potentially caused by adverse reaction to metal debris (ARMD). This study aimed to evaluate the outcome of dual mobility cup (DMC) constructs in revision THA for failed large head MoM bearings with a special attention to the occurrence of dislocation or re-revision. METHODS: Between 2015 and 2019, 57 patients (64 THAs, 41 men, mean age = 65 ± 10 years) underwent revision for MoM THA with the use of DMC were prospectively included in our total joint registry. Mean time to revision was 11 ± 2.5 years. The causes for revision were adverse reaction to metal debris (ARMD) in 49 THAs (76%), painful hip with elevated blood cobalt-chromium ions in seven (11%), and acetabular aseptic loosening in eight (13%). The revision was complete in 22 THAs (34%) and acetabular only in 42 (66%). Clinical and radiographic outcomes, complications, and re-revisions were evaluated at most recent follow-up. RESULTS: At mean follow-up of six ± 1.5 years, the pre- to postoperative Harris Hip Score improved from 74 ± 19 to 92 ± 4 (p = 0.004). Complications occurred in 11 cases (17%): five dislocations (8%), three periprosthetic infections (5%), two aseptic loosening of the acetabular component (3%), and two periprosthetic fractures (3%). Re-revision was required in six cases (9%). CONCLUSION: The use of DMC is a reliable option to prevent instability and ensure a stable acetabular reconstruction in revision THA for failed large head MoM bearings. However, dislocation after revision remains a concern, particularly in cases of severe soft tissue damage related to ARMD.

Direct Cementation of Dual Mobility Cups Into the Bony Acetabulum in Primary Total Hip Arthroplasty: Clinical and Radiographic Outcomes at a Minimum 5-Year Follow-Up.

BACKGROUND: Cemented dual mobility cups (DMCs) are commonly used in combination with acetabular reinforcement devices. Indeed, according to literature, direct cementation of metal-backed acetabular components into the bony acetabulum remains controversial as this technique is potentially associated with increased rates of aseptic loosening. Therefore, this study aimed to evaluate the clinical and radiographic outcomes of DMC cemented into the bony acetabulum in primary total hip arthroplasty (THA). METHODS: A total of 49 THA (48 patients, mean age 78 years [range, 51 to 91]) performed with direct cementation of a DMC into the bony acetabulum were prospectively included in our total joint registry and retrospectively reviewed. The clinical outcome was assessed using the Harris hip score (HHS). The radiographic outcome included measurement of component positioning and occurrence and progression of demarcation around the cemented DMC. Complications were reported with a particular attention to cemented fixation failure and aseptic loosening. RESULTS: At a 7-year mean follow-up (range, 5 to 8), the pre-to postoperative HHS improved from 47 (range, 30 to 58) to 92 points (range, 80 to 98) (P < .01). Nonprogressive and focalized demarcations were observed in 7 THA (14%). Importantly, no progressive demarcation or DMC aseptic loosening was observed. CONCLUSION: Direct cementation of DMC into the bony acetabulum ensured a stable fixation with no progressive demarcation or aseptic loosening at midterm follow-up. Therefore, this technique can be selectively considered in primary THA, especially in elderly or frail patients to avoid potential mechanical failure of press-fit fixation due to altered bone quality or additional morbidity related to the use of acetabular reinforcement devices.

Which femoral neck for a dual mobility cup? A biomechanical evaluation.

PURPOSE: This study aimed to evaluate polyethylene (PE) damage and wear lesions to the chamfer of mobile components under mobile and fixed femoral neck impingement at the third articulation, and to determine which femoral neck characteristics should be considered with a dual mobility cup to limit those lesions. METHODS: Two femoral neck geometries (cylindrical and quadrangular) with two surface finishing roughness (rough and polished), and two head-to-neck ratios (28- and 22.2-mm diameter femoral heads) were evaluated in a hip simulator testing. For each characteristic, six femoral necks were tested with six dual mobility cups under fixed and mobile femoral neck impingement conditions. Chamfer PE damage and volumetric wear were evaluated and compared for each femoral neck characteristic and impingement condition. RESULTS: Under mobile impingement condition, femoral neck characteristics did not significantly affect PE damage and wear lesions to the chamfer (p = 0.283 to 0.810). However, under fixed impingement condition, significantly higher PE damage and wear lesions to the chamfer were produced by the quadrangular geometry compared to the cylindrical geometry (p = 0.004 to 0.025). In addition, with the quadrangular geometry, rough surface finishing was demonstrated to increase volumetric wear of the chamfer (p = 0.009). No significant influence of head-to-neck ratio was observed on PE damage and wear lesions to the chamfer (p = 0.244 to 0.714). DISCUSSION: This biomechanical study emphasized that femoral neck characteristics are critical with dual mobility cup and tend to favor a cylindrical geometry particularly whether fixed impingement at the third articulation occurs.

Polyethylene wear of dual mobility cups: a comparative analysis based on patient-specific finite element modeling.

PURPOSE: Concerns remain about potential increased wear with dual mobility cups related to the multiple articulations involved in this specific design of implant. This finite element analysis study aimed to compare polyethylene (PE) wear between dual mobility cup and conventional acetabular component, and between the use of conventional ultra-high molecular weight PE (UHMWPE) and highly cross-linked PE (XPLE). METHODS: Patient-specific finite element modeling was developed for 15 patients undergoing primary total hip arthroplasty (THA). Five acetabular components were 3D modeled and compared in THA constructs replicating existing implants: a dual mobility cup with a 22.2-mm-diameter femoral head against UHMWPE or XLPE (DM22PE or DM22XL), a conventional cup with a 22.2-mm-diameter femoral head against UHMWPE (SD22PE) and a conventional cup with a 32-mm-diameter femoral head against UHMWPE or XLPE (SD32PE or SD32XL). RESULTS: DM22PE produced 4.6 times and 5.1 times more volumetric wear than SD32XL and DM22XL (p < 0.0001, Cohen's d = 6.97 and 7.11; respectively). However, even if significant, the differences in volumetric wear between DM22XL and SD32XL as well as between DM22PE and SD22PE or SD32PE were small according to their effect size (p < 0.0001, Cohen's |d|= 0.48 to 0.65) and could be therefore considered as clinically negligible. CONCLUSION: When using XLPE instead of UHMWPE, dual mobility cup with a 22.2-mm-diameter femoral head produced a similar amount of volumetric wear than conventional acetabular component with a 32-mm-diameter femoral head against XLPE. Therefore, XLPE is advocated in dual mobility cup to improve its wear performance.

[Partial knee arthroplasty - Which parameters to consider for the correct indication and to achieve an optimal result?] / Prothèse unicompartimentale du genou - Quels paramètres considérer pour poser la bonne indication et obtenir un résultat optimal ?

Unicompartmental knee arthroplasty (UKA) is considered an excellent alternative to total knee arthroplasty (TKA) in the treatment of unicompartmental femoro-tibial degeneration with superior functional scores, reduced morbidity and fewer complications. However, revision rates are higher, mainly during the early postoperative period. Failures are attributed to incorrect indications, surgical technical errors and to the low threshold to revision. Several clinical and radiological parameters have to be considered for a correct indication. A high surgical volume is mandatory to assure optimal outcome and survivorship.

La prothèse unicompartimentale du genou (PUC) est considérée comme une excellente alternative à la prothèse totale du genou (PTG) dans le traitement de l'arthrose monocompartimentale avec des scores fonctionnels supérieurs, une morbidité réduite et des taux de complications plus faibles. Cependant, les taux de révision sont plus élevés et se produisent principalement durant la période postopératoire précoce. Ils sont attribués à des indications incorrectes, à des erreurs chirurgicales et au fait que le seuil de révision est plus bas que pour une PTG. Plusieurs paramètres cliniques et radiologiques doivent être pris en considération afin de poser la bonne indication. Un volume chirurgical suffisant est nécessaire pour obtenir un résultat optimal et une survie prolongée de la PUC.

Total knee arthroplasty improves the quality-adjusted life years in patients who exceeded their estimated life expectancy.

PURPOSE: Total knee arthroplasty (TKA) is the treatment of choice for end-stage osteoarthritis though its risk-benefit ratio in elderly patients remains debated. This study aimed to evaluate the functional outcome, rates of complication and mortality, and quality-adjusted life years (QALY) in patients who exceeded their estimated life expectancy. METHODS: Ninety-seven TKA implanted in 86 patients who exceeded their estimated life expectancy at the time of TKA were prospectively included in our institutional joint registry and retrospectively analyzed. At latest follow-up, the functional outcome with the Knee Society Score (KSS), rates of complication and mortality, and QALY with utility value of EuroQol-5D score were evaluated. RESULTS: At a mean follow-up of three ± one years, the pre- to post-operative KSS improved significantly (p < 0.01). The rates of surgical and major medical complications related to TKA were 3% and 10%, respectively. The re-operation rate with readmission was 3% while no TKA was revised. The 30-day and one year mortality was 1% and 3%, respectively. The pre- to one year post-operative QALY improved significantly (p < 0.01). The cumulative QALY five years after TKA was four years. Assuming that these patients did not undergo TKA, their cumulative QALY at five years would have been only two years. CONCLUSION: TKA is an effective procedure for the treatment of end-stage osteoarthritis in patients who exceeded their estimated life expectancy. TKA provided significant improvement in function and quality of life without adversely affecting overall morbidity and mortality. Therefore, TKA should not be contra-indicated in elderly patients based on their advanced age alone.

Comparison of the long-term cause of failure and survivorship of four hundred and twenty seven metal-on-metal hip arthroplasties: resurfacing versus large head total hip arthroplasty.

INTRODUCTION: Comparison of mid- to long-term cause of failure and survivorship of metal-on-metal (MoM) resurfacing hip arthroplasty (RHA) and large head total hip arthroplasty (THA) remains sparse. This study aimed to identify and compare the cause of failure and survivorship of MoM RHA and THA at a minimum ten year follow-up. METHODS: Four hundred twenty-seven MoM hip arthroplasties (286 THA and 141 RHA) were retrospectively analyzed at a mean follow-up of 13 ± three years. Causes of failure were reported as MoM specific (i.e., adverse reaction to metal debris (ARMD) and painful hip with ion elevation) or MoM non-specific (i.e., fracture, infection, and dislocation). Chromium (Cr) and cobalt (Co) ion levels and Co/Cr ratio were compared. Survivorship was compared according to the cause of failure with revision as the endpoint. RESULTS: The rate of ARMD was significantly higher in THA (OR = 2.9 [95%-CI: 1-7]; p = 0.02). No significant difference was detected in failure rate due to other causes between the two groups (p = 0.2-0.9). Ion levels and Co/Cr ratio were both significantly higher in THA (p < 0.01). Survivorship was significantly lower in THA compared to RHA at ten years [89% (95%-CI: 85%-91%) vs 96% (95%-CI: 91%-98%); p = 0.01] and 15 years [73% (95%-CI: 67%-78%) vs 83% (95%-CI: 73%-90%); p = 0.01]. CONCLUSION: RHA survivorship was significantly higher at any time point. Failure rate due to ARMD was significantly higher in THA while no significant difference in other causes of failure was observed between the two groups. This result emphasizes the role of fretting corrosion at the head-neck junction (i.e., trunnionosis) with significantly higher ion levels and Co/Cr ratio dissociation in THA.

Hospital Length of Stay Reduction Over Time and Patient Readmission for Severe Adverse Events Following Surgery.

OBJECTIVE: The aim of the study was to investigate whether patients who undergo surgery in hospitals experiencing significant length of stay (LOS) reductions over time are exposed to a higher risk of severe adverse events in the postoperative period. SUMMARY BACKGROUND DATA: Surgical care innovation has encouraged hospitals to shorten LOS under financial pressures with uncertain impact on patient outcomes. METHODS: We selected all patients who underwent elective colectomy or urgent hip fracture repair in French hospitals between 2013 and 2016. For each procedure, hospitals were categorized into 3 groups according to variations in their median LOS as follows: major decrease, moderate decrease, and no decrease. These groups were matched using propensity scores based on patients' and hospitals' potential confounders. Potentially avoidable readmission for severe adverse events and death at 6 months were compared between groups using Cox regressions. RESULTS: We considered 98,713 patients in 540 hospitals for colectomy and 206,812 patients in 414 hospitals for hip fracture repair before matching. After colectomy, patient outcomes were not negatively impacted when hospitals reduced their LOS [hazard ratio (95% confidence interval): 0.93 (0.78-1.10)]. After hip fracture repair, patients in hospitals with major decreases in LOS had a higher risk of severe adverse events [1.22 (1.11-1.34)] and death [1.17 (1.04-1.32)]. CONCLUSIONS: Patients who underwent surgical procedures in hospitals experiencing major decreases in LOS were demonstrated worse postoperative outcomes after urgent hip fracture repair and not after elective colectomy. Development of care bundles to enhance recovery after emergency surgeries may allow better control of LOS reduction and patient outcomes.

Is Isolated Mobile Component Exchange an Option in the Management of Intraprosthetic Dislocation of a Dual Mobility Cup?

BACKGROUND: Intraprosthetic dislocation is a specific complication of dual mobility cups, although it occurs less frequently with the latest generations of implants. Intraprosthetic dislocation is related to long-term polyethylene wear of the mobile component chamfer and retentive area, leading to a snap-out of the femoral head. With the increased use of dual mobility cups, even in younger and active patients, the management of intraprosthetic dislocation should be defined according to its type. However, no previous studies, except for case reports, have described the strategy to manage long-term wear-related intraprosthetic dislocation, particularly when a dual mobility cup is not loose. QUESTIONS/PURPOSES: This study aimed to (1) determine the prevalence of intraprosthetic dislocation in this patient population and the macroscopic findings at the time of surgical revision and (2) evaluate whether isolated mobile component exchange could be an option to manage intraprosthetic dislocation occurring with a well-fixed dual mobility cup metal shell. METHODS: From January 1991 to December 2009, a continuous series of 5274 THAs with dual mobility cups (4546 patients; 2773 women; mean [range] age 58 years [22-87]; bilateral THA = 728) were prospectively enrolled in our institutional total joint registry. A cementless, hemispherical dual mobility cup was systematically implanted, regardless of the patient's age or indication for THA. At the latest follow-up examination, the registry was queried to isolate each occurrence of intraprosthetic dislocation, which was retrospectively analyzed regarding the patient's demographics, indication for THA, radiographs, intraoperative findings (polyethylene wear and lesion patterns on the mobile component, periarticular metallosis, and implant damage because of intraprosthetic impingement of the femoral neck), management of intraprosthetic dislocation (isolated exchange of the mobile component or revision of the dual mobility cup), and outcome. RESULTS: At a mean (range) follow-up duration of 14 years (3-26), 3% of intraprosthetic dislocations (169 of 5274) were reported, with a mean (range) time from THA of 18 years (13-22). Intraprosthetic dislocation occurred predominantly in younger men (mean [range] age at THA, 42 years [22-64] versus 61 years [46-87]; p < 0.001, and sex ratio (male to female, 1:32 [96 male and 73 female] versus 0.62 [1677 male and 2700 female]; p < 0.001) in patients with intraprosthetic dislocation and those without, respectively, but was not influenced by the indication for THA (105 patients with intraprosthetic dislocation who underwent THA for primary hip osteoarthritis and 64 with other diagnoses versus 3146 patients without who underwent THA for primary hip osteoarthritis and 1959 for other diagnoses (p = 0.9)). In all patients with intraprosthetic dislocation, a macroscopic analysis of the explanted mobile component revealed circumferential polyethylene wear and damage to the chamfer and retentive area, with subsequent loss of retaining power for the femoral head. Nine percent of intraprosthetic dislocations (16 of 169 patients with intraprosthetic dislocations) were associated with aseptic loosening of the dual mobility cup and were managed with acetabular revision without recurrence at a mean (range) follow-up duration of 7.5 years (5-11). Ninety-one percent of intraprosthetic dislocations (153 of 169) were pure, related to wear of the mobile component chamfer and retentive area without aseptic loosening of the dual mobility cup, and managed with isolated mobile component exchange. Intraprosthetic dislocation recurred in 6% (nine of 153) at a mean (range) follow-up interval of 3 years (2-4.5). Additionally, severe premature polyethylene wear of the mobile component with loosening of the dual mobility cup occurred in 12% of patients (19 of 153) at a mean (range) follow-up duration of 1.5 years (0.5-3). CONCLUSIONS: A failure rate of 18% (28 of 153 patients undergoing isolated mobile component exchange) was reported within 5 years after isolated mobile component exchange to manage intraprosthetic dislocation occurring with a well-fixed dual mobility cup metal shell. The two modes of failure were early recurrence of intraprosthetic dislocation or severe premature metallosis-related polyethylene wear of the mobile component with loosening of the dual mobility cup. Acetabular revision with synovectomy should remain the standard procedure to manage intraprosthetic dislocation, particularly if periarticular metallosis is present. The exception is intraprosthetic dislocation occurring in elderly or frail patients, for whom a conventional acetabular revision procedure would be associated with an unjustified surgical or anesthetic risk. LEVEL OF EVIDENCE: Level II, prognostic study.

Cementation of a Dual Mobility Cup Into an Existing Well-Fixed Metal Shell: A Reliable Option to Manage Wear-Related Recurrent Dislocation in Patients With High Surgical Risk.

BACKGROUND: During revision total hip arthroplasty (THA), the "double-socket" technique has been proposed as a straightforward solution in order to reduce the overall perioperative morbidity in patients with high surgical risk. However, the option of cementing a dual mobility cup into an existing well-fixed metal shell was sparsely reported. Therefore, this study aimed to evaluate the outcome of a "double-socket" technique performed with a cemented dual mobility cup in revision THA for late instability. METHODS: Twenty-eight revision THAs (28 patients) were performed for wear-related recurrent dislocation using a "double-socket" technique with a cemented dual mobility cup and retrospectively reviewed. The age at revision averaged 82 years (range 74-93). According to the American Society of Anesthesiologists (ASA) physical status classification, 12 patients (43%) were ASA II and 16 patients (57%) were ASA III before revision. RESULTS: At a mean follow-up of 3.5 years (range 2-5), the mean preoperative to postoperative functional outcome improved significantly (P < .01). The mean operative time was 107 minutes (range 75-140). The mean intraoperative bleeding was 200 mL (range 110-420). No postoperative complication, reoperation, or re-revision was reported. Importantly, no dislocation, dissociation of the cemented dual mobility cup construct, or aseptic loosening of the retained metal shell was observed. CONCLUSION: The "double-socket" technique with a dual mobility cup cemented into an existing well-fixed and well-positioned metal shell ensured a straightforward and blood-sparing revision technique that was efficient to restore stability and provide a secure acetabular construct in frail patients with high surgical risk and/or older than their natural life expectancy.

Total Hip Arthroplasty for Periacetabular Metastatic Disease. An Original Technique of Reconstruction According to the Harrington Classification.

BACKGROUND: Periacetabular metastatic disease requires complex acetabular reconstruction. The complication rate for these frail patients is high. Various cement-rebar reinforced techniques allowing cemented total hip arthroplasty (THA) have been described. The optimal procedure has not yet been identified. METHODS: A continuous series of 131 THAs performed in 126 patients with periacetabular metastatic disease was prospectively included in this study. After bone metastasis curettage and cementation, an original technique of acetabular reconstruction was performed using a dual mobility cup cemented into an acetabular reinforcement device (ie, Kerboull cross-plate or Burch-Schneider antiprotrusio cage) according to the Harrington classification. Functional outcome for independent ambulation in the community, pain relief, and occurrence of dislocation or mechanical failure of the acetabular reconstruction were assessed. RESULTS: At a mean follow-up of 33 ± 17 months, the improvement in the preoperative to postoperative functional outcome and pain relief was significant (P < .001). The dislocation rate was 2%. Two of the 3 cases of dislocation occurred in acetabular reconstructions associated with a proximal femoral arthroplasty. No mechanical failure or aseptic loosening of the acetabular reconstruction was observed. CONCLUSION: This study emphasized that our original technique combining bone metastasis curettage and cementation, acetabular reinforcement device and cemented dual mobility cup was effective to restore a painless functional independence and ensure a durable acetabular reconstruction able to face to adjuvant radiation therapy and mechanical solicitations for long survivors. In addition, dual mobility cup limited the risk of dislocation in patients undergoing THA for periacetabular metastatic disease.

The predictive factors of secondary patellar resurfacing in computer-assisted total knee arthroplasty. A prospective cohort study.

PURPOSE: The decision to resurface the patella during total knee arthroplasty (TKA) remains controversial. This prospective cohort study aimed to evaluate the outcome and survivorship of the native patella in computer-assisted TKA (CAS TKA) implanted for primary knee osteoarthritis, and to determine the predictive factors of secondary patellar resurfacing (SPR). METHODS: A prospective cohort of 273 cementless ultra-congruent mobile-bearing CAS TKA implanted without patellar resurfacing was included in our total joint registry. Patients were evaluated with the International Knee Society (IKS) and Hospital for Special Surgery Patellar (HSSP) scores. Radiographic evaluation was focused on the patellofemoral (PF) compartment to assess: the patellar dysplasia (Wiberg classification), PF osteoarthritis (Iwano classification), femoral trochlear dysplasia (femoral sulcus angle), patellar maltracking (patellar tilt and lateralization), and patella height (Blackburne-Peel ratio). RESULTS: At a six-year median follow-up, the CAS TKA survivorship using SPR as end-point was 95% (range, 91-99%). The IKS and HSSP improved significantly after SPR (p = 0.001 and 0.004, respectively). No significant difference in the IKS and HSSP was detected between TKA with native patella and SPR-TKA at latest follow-up. Importantly, four pre-operative radiographic PF parameters were significantly associated with SPR: higher stages of patellar dysplasia and PF osteoarthritis, and higher sulcus angle and patellar lateralization (hazard ratios = 5.1 to 11.6, p = 0.009 to 0.04). CONCLUSION: When preserving the native patella, surgeons should be aware of pre-operative PF radiographic parameters that could influence the outcome and survivorship of CAS TKA leading to SPR. Particularly, evidence of PF dysplasia, osteoarthritis and maltracking should be determined pre-operatively to resurface the patella at the time of TKA. LEVEL OF EVIDENCE: Therapeutic Level II (prospective cohort study).

The tridimensional geometry of the proximal femur should determine the design of cementless femoral stem in total hip arthroplasty.

PURPOSE: Using a cementless femoral stem in total hip arthroplasty (THA), optimal filling of the proximal femoral metaphyseal volume (PFMV) and restoration of the extramedullary proximal femoral (PF) parameters (i.e., femoral offset (FO), neck length (FNL), and head height (FHH)) constitute key goals for optimal hip biomechanics, functional outcome, and THA survivorship. However, almost 30% of mismatch between the PF anatomy and implant geometry of the most widely implanted non-modular cementless femoral stem has been demonstrated in a computed tomography scan (CT scan) study. Therefore, this anatomic study aimed to evaluate the relationship between the intra- and extramedullary PF parameters using tridimensional CT scan reconstructions. METHODS: One hundred fifty-one CT scans of adult healthy hips were obtained from 151 male Caucasian patients (mean age = 66 ± 11 years) undergoing lower limb CT scan arteriography. Tridimensional PF reconstructions and parameter measurements were performed using a corrected PF coronal plane-defined by the femoral neck and diaphyseal canal longitudinal axes-to avoid influence of PF helitorsion and femoral neck version on extramedullary PF parameters. RESULTS: Independently of the femoral neck-shaft angle, the PFMV was significantly and positively correlated with the FO, FNL, and FHH (r = 0.407 to 0.420; p < 0.0001). CONCLUSION: This study emphasized that the tridimensional PF geometry measurement in the corrected coronal plane of the femoral neck can be useful to determine and optimize the design of a non-modular cementless femoral stem. Particularly, continuous homothetic size progression of the intra- and extramedullary PF parameters should be achieved to assure stem fixation and restore anatomic hip biomechanics.

Highly crosslinked polyethylene: a safe alternative to conventional polyethylene for dual mobility cup mobile component. A biomechanical validation.

PURPOSE: Dual mobility cup (DMC) consists of a cobalt-chromium (CoCr) alloy cup articulated with a polyethylene (PE) mobile component capturing the femoral head in force using a snap-fit technique. This biomechanical study was the first to evaluate and compare the generation of cracks in the retentive area of DMC mobile components made of highly crosslinked PE (XLPE) or conventional ultra-high molecular weight PE (UHMWPE). METHODS: Eighty mobile components designed for a 52-mm diameter Symbol® DMC (Dedienne Santé, Mauguio, France) and a 28-mm diameter femoral head were analyzed. Four groups of 20 mobile components were constituted according to the PE material: raw UHMWPE, sterilized UHMWPE, annealed XLPE and remelted XLPE. Ten mobile components in each group were impacted with a 28-mm diameter CoCr femoral head using a snap-fit technique. The occurrence, location and area of the cracks in the retentive area were investigated using micro-CT (Skyscan 1176®, Bruker, Aarsellar, Belgium) with a 35 µm nominal isotropic voxel size by two observers blinded to the PE material and impaction or not of the mobile components. RESULTS: Compared to conventional UHMWPE, the femoral head snap-fit did not generate more or wider cracks in the retentive area of annealed or remelted XLPE mobile components. CONCLUSION: This biomechanical study suggests that XLPE in DMC could be a safe alternative to conventional UHMWPE regarding the generation of cracks in the retentive area related to the femoral head snap-fit.

Does computer-assisted surgery influence survivorship of cementless total knee arthroplasty in patients with primary osteoarthritis? A 10-year follow-up study.

PURPOSE: Computer-assisted surgery (CAS) has been proposed to improve the performance of total knee arthroplasty (TKA) by reducing implant mal-position and mechanical axis mal-alignment. However, no clinical study has been performed to evaluate whether CAS improves survivorship of cementless TKA at long-term follow-up. This prospective and comparative study evaluated the outcome and survivorship of a cementless rotating mobile-bearing TKA performed with or without CAS at a minimum 10-year follow-up. METHODS: A continuous series of 138 TKA (SCORE®, Amplitude, Valence, France) comparing 87 CAS TKA versus 51 conventional mechanical technique (MECA) TKA was prospectively included in our total joint registry. RESULTS: At 10.5 years after implantation, 95 TKA (59 CAS and 36 MECA TKA) were evaluated. No significant difference was detected in the clinical outcome and mechanical axis between the two groups. The overall 10-year survivorship using revision for any reason as end-point was 91 ± 5 % without significant difference detected between the two groups [86 ± 10 % in the MECA group and 94 ± 5 % in the CAS group (n.s.)]. Using aseptic loosening as end-point, the 10-year survivorship was 100 % in both groups. Using secondary patellar resurfacing as end-point, the 10-year survivorship was significantly higher in the CAS than in MECA group (100 and 85 ± 15 %, respectively; p = 0.0039). CONCLUSION: With no implant aseptic loosening or mechanical failure at 10.5 years after implantation, the cementless rotating mobile-bearing SCORE® TKA demonstrated favourable survivorship without influence of CAS. However, CAS might influence TKA survivorship by limiting secondary patellar resurfacing. LEVEL OF EVIDENCE: Therapeutic, Level II.

Fungaemia caused by Fusarium proliferatum in a patient without definite immunodeficiency.

Recent literature has shown the growing importance of opportunistic fungal infections due to Fusarium spp. However, disseminated fusariosis remains rare in patients without neutropenia. We report a case of fungaemia in a 78-year-old French woman without definite immunodeficiency. Fusarium proliferatum grew from both central and peripheral blood cultures. Fever was the only clinical sign of the infection. An appropriate antifungal therapy with voriconazole led to the recovery of the patient. An environmental investigation was undertaken but failed to find a reservoir of Fusarium spores. A contaminated central venous catheter might have been the source of fungaemia.