The role of isolated polyethylene exchange in total knee arthroplasty

IPE should be undertaken with caution and an institutional algorithm should be followed based on current literature. To our knowledge, there is no randomised clinical trial that compares different revision surgery for failed TKA. The purpose of this article is to review the current literature and registry results, and outline an algorithm for the role of IPE in revision TKA. Non-fluorinated anion exchange polymers with sufficient ion exchange capacity, mechanical integrity and hydroxide-ion stability are required for the progression of alkaline electrochemical energy conversion devices.

Polyethylene Exchange Only for Prosthetic Knee Instability

Patients may be asymptomatic early in the disease, but most will present with pain, swelling or acute synovitis. Serial radiographs, including oblique views,14 will be necessary to monitor the progression of the disease. how to buy polymath If the patient becomes symptomatic or the osteolysis is progressive, surgery is considered. Existing short and midterm studies demonstrate no differences in revision rates between XLPE and CPE in TKA [32,34].

Polyethylene Exchange Only for Prosthetic Knee Instability : Clinical Orthopaedics and Related Research®

• A humidity cycling degradation protocol, exposing the polymers to as low as 10 % relative humidity at 80 °C was implemented to reveal the relative chemical (in)stabilities of the polymers in extreme caustic conditions under accelerated timeframes.
• The symptoms of prosthetic knee instability include catching, giving way, anterior knee pain, pes bursitis, and the inability to trust the knee in daily activities.
• In patients with a stemmed implant, an anterior femoral cortex osteotomy or a complete window may be created to allow component loosening or to remove residual cement.15 The last step is to remove the tibial component.
• Results should follow the validated criteria of the International Consensus Meeting.6 Do not hesitate to retry intraarticular aspiration in ‘dry tap’ knees.
• This classification is based on the presence of impurities such as titanium, aluminum, chlorine, calcium, as well as storage and handling properties.
• For these reasons, some manufacturers prefer the preservation of mechanical properties to wear properties in an attempt to avoid such delamination.

The manufacturers have utilized different PE processing methods, which can influence PE’s long-term performance. Surgeons are encouraged to critically look for specific failure mechanisms based on these processing techniques. Of the 29 patients revised with a type 3 instability pattern (global instability), 6 (21%) were re-revised and 4 declined to answer questions concerning pain and stability. Only 11 patients of the 19 (58%) revised for global instability were satisfied with their pain relief, whereas 8 (42%) were dissatisfied. Therefore, of the 29 patients, 12 (41%) were either re-revised or remained unstable after PE only for global instability.

Alkaline stability of pendant C2-protected poly(imidazolium)s†

The patient is then placed on weekly follow-up until satisfactory motion is achieved. If the movement is still limited at six weeks, we discuss the option of manipulation under anaesthesia. In patients who present later than three months, https://www.tokenexus.com/ we may consider open arthrolysis with liner exchange if the components are well-aligned and well-fixed. Post-operatively, patients are placed on epidural anaesthesia, continuous passive motion and aggressive physiotherapy.

IPE for wear and osteolysis

The tibial keel can be manually re-prepared in appropriated rotation using a bone nibbler or reciprocating saw. If a medial or a lateral peripherical bone defect is present a trial augment is added under the plastic tibia on the corresponding side and the varus-valgus alignment is re-checked. The use of a porous metal cones or sleeves revision system is mandatory in the presence of central defects in this area. The metaphysis (zone 2) is considered as the most important zone for a long-term implant fixation, as it avoids stress shielding phenomena correlated with a diaphyseal-only fixation. A closer fixation to the joint line also provides a better restoration of joint line and axial/rotational stability, and it is possible to remove in case of re-revision, much more easily than extensive cemented or osteo-integrated stems. The epiphyseal region (zone 1) is partially or completely compromised in every revision by the failure process or the hardware removal.

• A variety of modular polyethylene inserts were used depending on the type of instability pattern present and the available inserts to match the existing implant (Table ​(Table11).
• A type 2 instability pattern is probably the most common type of periprosthetic knee instability, that is, flexion-extension mismatch.
• Before performing bony resection, a soft-tissue release should be done by stripping the posterior capsule and soft tissue off the posterior distal femur.
• Of the six patients revised with a type 1A instability pattern (coronal instability with competent ligaments), three (50%) remained unstable and one required re-revision.
• Spacer blocks placed in full extension must match a spacer block placed at 90° of flexion to stabilize the knee.