Revision for stiff knee after knee replacement.

Stiffness following total knee replacement is defined as >15° flexion contracture and/or flexion <75° or, for other authors, arc of motion <70° or 45° or 50°. Alternatively, it could be defined as a range of motion less than the patient needs in order to be able to do what they wish. The first step in management is to determine the causes: preoperative (history of stiffness, patient-related risk factors, etc.

Performance of the GeneXpert® MRSA/SA SSTI test in periprosthetic joint infections: rate of failure, outcomes and risk factors.

Background: The GeneXpert® MRSA/SA SSTI test allows early detection of methicillin-resistant staphylococci in intraoperative samples of prosthetic joint infections (PJI) in order to stop early broad-spectrum antibiotics.

Questions/purpose: (1) What is the rate of false-negative GeneXpert® MRSA/SA SSTI test results? (2) Does a false-negative GeneXpert® MRSA/SA SSTI test result increase the risk of treatment failure for the patient with a PJI? (3) What are the risk factors of a false-negative result?

Method: A retrospective study was carried out to compare all GeneXpert® assays to conventional cultures in prosthetic joint infections from April 1st, 2012 to October 1st, 2016. False-negative (FN) results (absence of methicillin-resistant staphylococci (MRS) with GeneXpert® test, but presence in the culture) were identified.

Can the minimal clinically important difference (MCID) for the Oxford score, KOOS and its derivatives be identified in a French sample of total knee arthroplasties?

Context: To assess the effect of a surgical procedure on a patient, it is conventional to use clinical scores before and after the procedure, but it is increasingly common and recommended to weight the results of these scores with the notion of minimal clinically important difference ("MCID"). This MCID should be determined using either the data distribution method based on score variation, or the anchor method, which uses an external question to categorize the results. MCIDs vary from one population to another, and to our knowledge there has been no investigation in France for total knee arthroplasties (TKAs).

Long-term results (after a mean 11.3years, and up to 22years, of follow-up) of the Legacy Constrained Condylar Knee (LCCK™) in primary total knee arthroplasty.

Introduction: The use of a sliding prosthesis in total knee arthroplasty (TKA) with increased stress is an intermediate solution in primary surgery, between posteriorly stabilized prostheses and hinged prostheses, in cases of ligamentous laxity and/or loss of bone substance. Favorable results have been reported in the medium term but to our knowledge, this type of prosthesis has not been evaluated in Europe beyond 10 years of follow-up. We therefore conducted a retrospective study in order to carry out: 1) the study of the survival of the Legacy Constrained Condylar Knee (LCCK™) prosthesis in primary surgery, 2) the analysis of complications, functional scores and radiographic data, 3) the analysis of the link between the diaphyseal filling rate and prosthetic loosening.

Management of medial femorotibial osteoarthritis: Epidemiology, and survival of unicompartmental knee arthroplasty versus valgus high tibial osteotomy in France. Study of 108,007 cases from the French National Hospitals Database.

Introduction: Unicompartmental knee arthroplasty (UKA) and valgus high tibial osteotomy (HTO) are two options for isolated medial femorotibial osteoarthritis in genu varum. In the absence of registries for osteotomies and for arthroplasty in the knee, epidemiological data are hard to obtain in France. We therefore performed a retrospective study, with the aims of: 1) estimating UKA and HTO survival without revision by total knee arthroplasty (TKA), and 2) assessing risk factors for revision according to treatment group.

Should microbiological samples be taken routinely when performing revision surgery for post-surgical hematoma after hip or knee replacement? Retrospective study of 78 cases of surgically drained hematoma with a minimum follow-up of 2 years.

Introduction: The relationship between the occurrence of a periprosthetic hip or knee joint infection, a post-surgical hematoma and the time to surgical revision, along with the need to take samples for microbiology analysis has not been clearly defined. This led us to perform a retrospective study to: 1) define the rate of infected hematoma and subsequent infection after surgical revision for hematoma and 2) analyze in which time frame the hematoma was likely to be infected.

Hypothesis: The more time elapsed before the postoperative hematoma is drained surgically after hip or knee replacement, the higher the hematoma infection rate and the late infection rate.

Trajectory of chronic and neuropathic pain, anxiety and depressive symptoms and pain catastrophizing after total knee replacement. Results of a prospective, single-center study at a mean follow-up of 7.5 years.

Introduction: A considerable number of patients are not satisfied after total knee replacement (TKR) because of persistent pain. This pain can also be neuropathic in origin. Both types of pain have a large impact on function and quality of life.

Tibiofemoral lift-off and resulting laxity following total knee arthroplasty: Frequency in a series of 906 continuous cases and functional consequences at 4 years' follow-up in a case-control study.

Background: Tibiofemoral instability is one reason for early revision of total knee arthroplasty. It can be the consequence of tibiofemoral laxity, especially in the coronal plane with tibiofemoral lift-off. But does femoral condyle lift-off on conventional postoperative radiographs suggest the presence of laxity or potential instability? To our knowledge, this question has not yet been answered.

The extracellular matrix of human bone marrow adipocytes and glucose concentration differentially alter mineralization quality without impairing osteoblastogenesis.

Bone marrow adipocytes (BMAds) accrue in various states of osteoporosis and interfere with bone remodeling through the secretion of various factors. However, involvement of the extracellular matrix (ECM) produced by BMAds in the impairment of bone marrow mesenchymal stromal cell (BM-MSC) osteoblastogenesis has received little attention. In type 2 diabetes (T2D), skeletal fragility is associated with several changes in bone quality that are incompletely understood, and BMAd quantity increases in relationship to poor glycemic control.

Complications and outcomes of trochleoplasty for patellofemoral instability: A systematic review and meta-analysis of 1000 trochleoplasties.

Background: Trochleoplasty is an effective patellar stabilization procedure; however, it is associated with a risk of complications that cannot be ignored. Prior systematic reviews on this topic did not include more recent studies reporting important outcomes, particularly the long-term results of lateral elevation trochleoplasty. This led us to carry out a new meta-analysis of the various trochleoplasty procedures to specify: (1) the recurrence rate of patellofemoral dislocation; (2) the complication rates and; (3) the clinical outcomes.

Does the alpha-defensin lateral flow test conserve its diagnostic properties in a larger population of chronic complex periprosthetic infections? Enlargement to 112 tests, from 42 tests in a preliminary study, in a reference center.

Background: Diagnosis of periprosthetic infection (PPI) is crucial for management of bone and joint infection. The preoperative gold-standard is joint aspiration, providing results after 2-14 days' culture, with non-negligible false negative rates due to the fragility of certain micro-organisms and/or prior antibiotic treatment. The Synovasure™ alpha-defensin lateral flow test (Zimmer, Warsaw, IN, USA) contributes within minutes to joint fluid diagnosis of almost all infectious agents, including in case of concomitant antibiotic therapy.

Above-the-knee amputation versus knee arthrodesis for revision of infected total knee arthroplasty: Recurrent infection rates and functional outcomes of 43 patients at a mean follow-up of 6.7 years.

Introduction: In cases of repeated treatment failure of periprosthetic joint infections (PJI) of the knee, above-the-knee amputation (AKA) or knee arthrodesis can be proposed to reduce the risk of recurrent infection, especially in cases with major bone defects or irreparable damage to the extensor mechanism of the knee. Since AKA versus knee arthrodesis results have been rarely assessed for these indications, we conducted a retrospective case-control study to compare both the rates of recurrent infection and functional outcomes. Hypothesis Patients who underwent AKA had fewer recurrent infections than those who had arthrodesis.

Complications and failures of non-tumoral hinged total knee arthroplasty in primary and aseptic revision surgery: A review of 290 cases.

Introduction: Hinged total knee arthroplasty (TKA) implants are a commonly used option during revision or even primary surgery, but their complications are not as well known, due to the rapid adoption of gliding implants. The literature is inconsistent on this topic, with studies having a small sample size, varied follow-up duration and very different indications. This led us to carry out a large multicentre study with a minimum follow-up of 5 years to evaluate the complications after hinged TKA in a non-tumoral context based on the indications of primary arthroplasty, aseptic surgical revision or fracture treatment around the knee.

The advantages of cone-beam computerised tomography (CT) in pain management following total knee arthroplasty, in comparison with conventional multi-detector CT.

Background: Revision of total knee arthroplasty (TKA) requires preoperative assessment to identify the causes of failure. Multidetector computerised tomography (MDCT) is a commonly used imaging technique, but is sensitive to certain artifacts, such as metal implants, limiting its use. Cone-beam CT (CBCT) is a new technique dedicated to musculoskeletal imaging that is less sensitive to artifacts and could be utilised in knee implantation surgery.

A retrospective comparison of central and posterior hinge joints in 53 total knee arthroplasties.

Introduction: The number of hinged total knee arthroplasty (HTKA) procedures is constantly increasing. There are two hinge types: central (CHTKA) and posterior (PHTKA). The primary purpose of the study was to compare implant survival in patients with CHTKA versus PHTKA.

Rotating-hinge prosthesis for aseptic revision knee arthroplasty: A multicentre retrospective study of 127 cases with a mean follow-up of five years.

Background: The use of third-generation rotating-hinge knee prostheses has increased considerably in recent years. The more anatomical design of these prostheses, together with their controlled rotation system that reduces constraints generated by the single degree of liberty, have produced better outcomes. The objective of this study was to evaluate the clinical and radiological outcomes of revision knee arthroplasty for aseptic failure using rotating-hinge prostheses.

Can the minimal clinically important difference be determined in a French-speaking population with primary hip replacement using one PROM item and the Anchor strategy?

Background: The impact of surgery on the patient is classically assessed on pre- and post-treatment scores. However, it is increasingly recommended to rank these results according to the minimal clinically important difference (MCID), using either the data distribution method or the anchor method, latter consisting in an extra question specifically targeting the patient's improvement. MCIDs vary between populations and, to the best of our knowledge; there have been no investigations in France regarding this in the context of total hip replacement (THR).

Does change in language change the properties of a shortened score previously validated in its complete version? Validation of the French versions of the HOOS-12 and KOOS-12 scores in primary knee and hip arthroplasties.

Background: The HOOS and KOOS scoring questionnaires comprise respectively 40 and 42 items; a shorter 12-item version was recently developed, but remains to be validated in a French-speaking population. We therefore conducted a prospective study: 1) to determine whether the new 12-item versions in French are equivalent to the longer HOOS and KOOS versions, and 2) to validate the French-language HOOS-12 and KOOS-12 patient-reported outcome measures in a population of primary total hip and knee arthroplasty: validity, reliability, and responsiveness.

Hypothesis: The change in language in a score already validated in its long version does not alter its properties in the short version.

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.

Survival and complications in hinged knee reconstruction prostheses after distal femoral or proximal tibial tumor resection: A retrospective study of 161 cases.

Introduction: Hinged knee megaprostheses are mainly used for reconstruction after tumor resection. They may incur complications, but this has not been assessed in the French literature, except in small series at short follow-up. We therefore conducted a large-scale nationwide multicenter retrospective study with a minimum 5 years' follow-up.

Hinged total knee arthroplasty for fracture cases: Retrospective study of 52 patients with a mean follow-up of 5 years.

Introduction: Hinged total knee arthroplasty (hTKA) is one of the treatment options available for complex fractures around an intact knee or an existing implant. The primary objective of this multicenter study was to evaluate the medium-term outcomes of hTKA for fractures. The secondary objective was to analyze the complications and risk factors based on fracture type, predisposition and time to surgery.

Prospective randomized study using EBRA-FCA to compare bone fixation between cementless SL-PLUS Zweymüller versus SL-PLUS MIA femoral implants in primary total hip arthroplasty with clinical assessment at a minimum 5years' follow-up.

Introduction: Sometimes the slightest changes in implant design can lead to failure, even for a validated prosthesis. A minimally invasive cementless model, the SL-PLUS MIA™, in which the lateral shoulder is eliminated, was developed from the Zweymüller SL-PLUS™ implant. After satisfactory in-vitro tests, it required in-vivo assessment to ensure that bone fixation is good.

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.