Post-meniscectomy syndrome is broadly characterised by intractable pain following the partial or total removal of a meniscus. There is a large treatment gap between the first knee pain after meniscectomy and the eligibility for a TKA. Hence, there is a strong unmet need for a solution that will relieve this post-meniscectomy pain. Goal of this first-in-man study was to evaluate the safety and performance of an anatomically shaped artificial medial meniscus prosthesis and the accompanying surgical technique. A first-in-man, prospective, multi-centre, single arm clinical investigation was intended to be performed on 18 post-medial meniscectomy syndrome patients with limited underlying cartilage damage (Kellgren Lawrence scale 0–3) in the medial compartment and having a normal lateral compartment. Eventually 5 patients received a polycarbonate urethane mediale meniscus prosthesis (Trammpolin® medial meniscus prosthesis; ATRO Medical B.V., the Netherlands) which was clicked onto two titanium screws fixated at the native horn attachments on the tibia. PROMs were collected at baseline and at 6 weeks, 3, 6, 12 and 24 months following the intervention including X-rays at 6, 12 and 24 Months. MRI scans were repeated after 12 and 24 months.Introduction
Methods
A bicruciate retaining (BCR) TKA is thought to maintain a closer resemblance to the native knee kinematics compared to a posterior cruciate retaining (CR) TKA. With BCR TKAs retainment of the anterior cruciate ligament (ACL) facilitates proprioception and balance which is thought to lead to more natural knee kinematics and increased functional outcome. The aim of this study was to quantify and compare the kinematics of a BCR and CR TKA during functional tests. In this patient-blinded randomized controlled trial, a total of 40 patients with knee osteoarthritis were included, 18 of them received a BCR TKA (Vanguard XP, Zimmer-Biomet) and 22 received a CR TKA (Vanguard CR, Zimmer-Biomet). Fluoroscopic analysis was done 1 year post-operatively. The main outcome was posterior femoral rollback (i.e. translation of the femorotibial contact point (CP)) of the BCR and CR TKA during a step-up test. Secondary, the kinematics during a lunge test were quantified as anterior-posterior (AP) translation of the femorotibial CP. Independent student t-tests (or non-parametric equivalent) were used to analyze the effect of BCR versus CR TKA on these measures, to correct for the multiple testing problem post-hoc Bonferroni-Holm corrections were applied.Introduction
Materials and Methods
To improve implant positioning in total knee arthroplasty (TKA) patient-specific instrumentation (PSI) has been introduced as alternative for conventional instrumentation (CI). Though the PSI technique offers interesting opportunities in TKA, there is no consensus about the effectiveness of PSI in comparison with CI and results concerning soft-tissue balancing remain unclear. Therefore, the primary aim of the present study was to investigate the varus-valgus laxity in extension and flexion in patients receiving a TKA using PSI compared with CI. Additionally, radiological, clinical and functional outcomes were assessed. In this prospective randomization controlled trial, 42 patients with osteoarthritis received a Genesis II PS (Smith & Nephew, Memphis, Tennessee), with either PSI (Visionaire, Smith & Nephew) or CI (Smith & Nephew). Patients visited the hospital preoperative and postoperative after 6 weeks, 3 and 12 months. One-year postoperative varus-valgus laxity was measured in extension and flexion on stress radiographs. Additional assessments included: the hip-knee-ankle angle on long-leg radiographs, femoral and tibia component rotation on CT-scans, radiolucency, the Knee Society Score (KSS), VAS pain, VAS Satisfaction, Knee injury and Osteoarthritis Outcome score (KOOS), Patella score (Kujala), the University of California Los Angeles activity score (UCLA), the anterior-posterior laxity in 20° and 90° knee flexion, adverse events and complications. The outcome measures were compared using independent t-tests, non-parametric alternatives and repeated measurements, with a significance level of p<0.05.Background
Methods
An important factor in the functional results after total knee arthroplasty (TKA) is the achieved maximal flexion. To date, a TKA still provides dissimilar flexion capabilities compared to the healthy knee, which could be due to the mismatch between the normal knee geometry and the implant geometry. The implant design of the Journey (Smith&Nephew) aims to replicate the normal knee function. According to the manufacturer of the Journey system, it intends to replicate PCL and ACL function, accommodates deep flexion, induces normal tibiofemoral axial rotation and provides proper patellar tracking throughout the entire range of flexion (‘guided motion’). The objective of this study is to investigate the maximal knee flexion one year after surgery of the Journey and its predecessor the Genesis II (Smith&Nephew). In addition, clinical and functional outcomes will be evaluated. A total of 124 patients presenting with noninflammatory osteoarthritis received the Journey or the Genesis II prosthesis, by randomization. The primary outcome was defined as the maximum flexion angle on a lateral X-ray performed with the patient lying on a bench and using manual force on bending the knee. Secondary outcomes were: active flexion (lying and standing), Knee Society System score (KSS), Patella Scoring System (PSS), number of adverse events (AE) and satisfaction. The changes in KSS and PSS between the pre-operative situation and 1 year after surgery were calculated as: δKSS = KSS1 year – KSSpre-op, and δPSS = PSS1 year – PSSpre-op. Two-sided t-tests and non-parametric alternatives were performed in order to test for differences between the Journey and the Genesis II group.Introduction
Methods
Highly cross-linked polyethylene (XLPE) has been introduced in total hip arthroplasty in an effort to reduce polyethylene wear and the associated periprohetic osteolysis. Cross-linking is a procedure in which irradiation and subsequent heating stabilize the internal structure of PE. Most of the conventional PE’s used, are gamma irradiated in air or an inert environment with a dose level of no more than 25 to 50 kGy. By irradiating PE at a higher dose, optimally around 95–100 kGy, a definite reduction in wear rate has been achieved. History already provided us some mixed in vivo results regarding altered PE. Therefore, present time surgeons are cautious when it comes down to using a new PE. Some short follow up in vivo studies already suggested reduced wear rates with XLPE in comparison to conventional PE. Our aim was to demonstrate these reduced wear rates in a 2-dimensional head penetration model using the DICOMeasure™ computerized edge detection method (GreyStone, France) and to perform a clinical comparison of both groups using the Harris Hip Score and SF-36 questionnaire. Sixty hips with a Trilogy XLPE liner (Zimmer Co.) were age and BMI matched with a control group of twenty conventional Trilogy PE liners (Zimmer Co.). No differences in clinical performance were seen, but a statistically significant reduction of 67% in steady state wear rate was observed in the XLPE group. It is clear that, due to the reduction and stabilization of free radicals in polyethylene, a reduction in annual wear can be achieved.
