• The use of modular total knee arthroplasty (TKA) implants allows surgeons to perform isolated tibial polyethylene insert exchange (IPE) while retaining well-fixed and stable components.

• The purported advantages of IPE include preservation of bone stock, shorter operating time, less blood loss, faster rehabilitation and lower cost. However, the indications for IPE are limited.

• IPE for wear and osteolysis has moderate success in the medium term but should be avoided in cases of accelerated wear. In selected cases, debridement and IPE for early infection can result in low morbidity with high success rates in the short term. IPE for arthrofibrosis has poor results.

• IPE should be undertaken with caution and an institutional algorithm should be followed.

Cite this article: EFORT Open Rev 2017;2:66–71 DOI: 10.1302/2058-5241.2.160049

• Knee osteoarthritis (OA) is a painful and incapacitating disease affecting a large portion of the elderly population, for which no cure exists. There is a critical need to enhance our understanding of OA pathogenesis, as a means to improve therapeutic options.

• Knee OA is a complex disease influenced by many factors, including the loading environment. Analysing knee biomechanics during walking - the primary cyclic load-bearing activity - is therefore particularly relevant.

• There is evidence of meaningful differences in the knee adduction moment, flexion moment and flexion angle during walking between non-OA individuals and patients with medial knee OA. Furthermore, these kinetic and kinematic gait variables have been associated with OA progression.

• Gait analysis provides the critical information needed to understand the role of ambulatory biomechanics in OA development, and to design therapeutic interventions. Multidisciplinary research is necessary to relate the biomechanical alterations to the structural and biological components of OA.

Cite this article: Favre J, Jolles BM. Analysis of gait, knee biomechanics and the physiopathology of knee osteoarthritis in the development of therapeutic interventions. EFORT Open Rev 2016;1:368-374. DOI: 10.1302/2058-5241.1.000051.

• Total joint arthroplasty (TJA) is one of the most common orthopaedic procedures. Nevertheless, several complications can lead to implant failure.

• Peri-prosthetic joint infections (PJI) certainly represent a significant challenge in TJA, constituting a major cause of prosthetic revision. The surgeon may have an important role in reducing the PJI rate by limiting the impact of significant risk factors associated to either the patient, the operative environment or the post-operative care.

• In the pre-operative period, several preventive measures may be adopted to manage reversible medical comorbidities. Other recognised pre-operative risk factors are urinary tract infections, intra-articular corticosteroid injections and nasal colonisation with Staphylococcus (S.) aureus, particularly the methicillin-resistant strain (MRSA).

• In the intra-operative setting, protective measures for PJI include antibiotic prophylaxis, surgical-site antisepsis and use of pre-admission chlorhexidine washing and pulsed lavage during surgery. In this setting, the use of plastic adhesive drapes and sterile stockinette, as well as using personal protection systems, do not clearly reduce the risk of infection. On the contrary, using sterile theatre light handles and splash basins as well as an increased traffic in the operating room are all associated with an increased risk for PJI.

• In the post-operative period, other infections causing transient bacteraemia, blood transfusion and poor wound care are considered as risk factors for PJI.

Cite this article: Ratto N, Arrigoni C, Rosso F, Bruzzone M, Dettoni F, Bonasia DE, Rossi R. Total knee arthroplasty and infection: how surgeons can reduce the risks. EFORT Open Rev 2016;1: 339-344 DOI: 10.1302/2058-5241.1.000032.

• Bone marrow lesions (BML) of the knee are a frequent MRI finding, present in many different pathologies including trauma, post-cartilage surgery, osteoarthritis, transient BML syndromes, spontaneous insufficiency fractures, and true osteonecrosis.

• Osteonecrosis (ON) is in turn divided into spontaneous osteonecrosis (SONK), which is considered to be correlated to subchondral insufficiency fractures (SIFK), and avascular necrosis (AVN) which is mainly ascribable to ischaemic events.

• Every condition has a MRI pattern, a different clinical presentation, and specific histological features which are important in the differential diagnosis.

• The current evidence supports an overall correlation between BML and patient symptoms, although literature findings are variable, and very little is known about the natural history and the progression of these lesions.

• A full understanding of BML will be mandatory in the future to better address the different pathologies and develop appropriately-targeted treatments.

Cite this article: Marcacci M, Andriolo L, Kon E, Shabshin N, Filardo G. Aetiology and pathogenesis of bone marrow lesions and osteonecrosis of the knee. EFORT Open Rev 2016;1:219-224. DOI: 10.1302/2058-5241.1.000044.

• Post-traumatic knee arthritis is a challenging condition. Prosthetic surgery is demanding and the risk of complications is relatively high.

• Planning is an essential element of this surgery; correct diagnosis (to exclude latent infection) and adequate considerations regarding approach, axis, bone loss, choice of implant and level of constraint are indispensable.

• There are two main categories of post-traumatic arthritis: extra-articular deformities and articular deformities.

• Use of an algorithms can support the surgeon’s choice of implant.

• Correct implant positioning and limb alignment restoration is associated with very good results, similar to those achieved with standard total knee arthroplasty.

Cite this article: Benazzo F, Rossi SMP, Combi A, Meena S, Ghiara M. Knee replacement in chronic post-traumatic cases. EFORT Open Rev 2016:1:211-218. DOI: 10.1302/2058-5241.1.000025.

• Revision total knee arthroplasty (rTKA) is a challenging, complex procedure. A comprehensive understanding of the anatomy, challenges and pitfalls is essential to achieve a good outcome for the patient.

• This review discusses the determinants of good outcomes of rTKA. These include, among other factors, the choice of the surgical approach, removal of the components, adequate reconstruction of the joint line and posterior condylar offset and the use of offset stems, as well as choosing the appropriate level of constraint.

• The modularity of many modern knee revision systems can help to address such issues as anatomical mismatch, gap balancing and malalignment.

• A well-planned surgical approach must be used in rTKA. A thorough understanding of related knee anatomy is essential.

• The incidence of joint-line elevation after rTKA is high. Contralateral radiographs, as well as algorithms based on the relationship between bony landmarks and the joint line, can help to reconstruct a physiological joint line during rTKA.

• Modularity added to systems, such as offset stems, are useful enhancements that may further improve the reconstruction of the anatomy.

• There are several options for managing the patella, with the best choice depending on the status of the patellar component and residual bone stock.

Cite this article: Thienpont E. Revision knee surgery techniques. EFORT Open Rev 2016;1: 233-238. DOI: 10.1302/2058-5241.1.000024.

• Tibial plateau fractures are complex injuries produced by high- or low-energy trauma. They principally affect young adults or the ‘third age’ population.

• These fractures usually have associated soft-tissue lesions that will affect their treatment. Sequential (staged) treatment (external fixation followed by definitive osteosynthesis) is recommended in more complex fracture patterns. But one should remember that any type of tibial plateau fracture can present with soft-tissue complications.

• Typically the Schatzker or AO/OTA classification is used, but the concept of the proximal tibia as a three-column structure and the detailed study of the posteromedial and posterolateral fragment morphology has changed its treatment strategy.

• Limb alignment and articular surface restoration, allowing early knee motion, are the main goals of surgical treatment. Partially articular factures can be treated by minimally-invasive methods and arthroscopy is useful to assist and control the fracture reduction and to treat intra-articular soft-tissue injuries.

• Open reduction and internal fixation (ORIF) is the gold standard treatment for these fractures. Complex articular fractures can be treated by ring external fixators and minimally-invasive osteosynthesis (EFMO) or by ORIF. EFMO can be related to suboptimal articular reduction; however, outcome analysis shows results that are equal to, or even superior to, ORIF. The ORIF strategy should also include the optimal reduction of the articular surface.

• Anterolateral and anteromedial surgical approaches do not permit adequate reduction and fixation of posterolateral and posteromedial fragments. To achieve this, it is necessary to reduce and fix them through specific posterolateral or posteromedial approaches that allow optimal reduction and plate/screw placement.

• Some authors have also suggested that primary total knee arthroplasty could be an option in specific patients and with specific fracture patterns.

Cite this article: Prat-Fabregat S, Camacho-Carrasco P. Treatment strategy for tibial plateau fractures: an update. EFORT Open Rev 2016;1:225-232. DOI: 10.1302/2058-5241.1.000031.

• Recent studies have challenged the long-held notion that neutral mechanical alignment after total knee arthroplasty leads to optimal function and survivorship.

• The ideal alignment for function and survivorship may actually be different.

• Kinematic alignment, where components are implanted to re-create the natural flexion/extension axis of the knee, may lead to improved functional results.

• Residual varus alignment may not adversely impact survivorship provided the tibial component is implanted in neutral alignment.

Cite this article: Lording T, Lustig S, Neyret P. Coronal alignment after total knee arthroplasty. EFORT Open Rev 2016;1:12-17. doi: 10.1302/2058-5241.1.000002.

• Patients with unstable, malaligned knees often present a challenging management scenario, and careful attention must be paid to the clinical history and examination to determine the priorities of treatment.

• Isolated knee instability treated with ligament reconstruction and isolated knee malalignment treated with periarticular osteotomy have both been well studied in the past. More recently, the effects of high tibial osteotomy on knee instability have been studied.

• Lateral closing-wedge high tibial osteotomy tends to reduce the posterior tibial slope, which has a stabilising effect on anterior tibial instability that occurs with ACL deficiency.

• Medial opening-wedge high tibial osteotomy tends to increase the posterior tibia slope, which has a stabilising effect in posterior tibial instability that occurs with PCL deficiency.

• Overall results from recent studies indicate that there is a role for combined ligament reconstruction and periarticular knee osteotomy.

• The use of high tibial osteotomy has been able to extend the indication for ligament reconstruction which, when combined, may ultimately halt the evolution of arthritis and preserve their natural knee joint for a longer period of time.

Cite this article: Robin JG, Neyret P. High tibial osteotomy in knee laxities: Concepts review and results. EFORT Open Rev 2016;1:3-11. doi: 10.1302/2058-5241.1.000001.