Experience with Metal on Metal (MoM) hip resurfacing devices has shown adequate cementation of the femoral head is critical for implant survival. Bone necrosis can be caused by the temperature change in the peri-prosthetic bone whilst the cement cures during implantation. This can lead to implant loosening, head/neck fracture and implant failure. During the implantation it is known that implants change shape potentially altering joint clearance and causing loosening. Given the history of Metal on Metal implant failure due adverse tissue reactions from Cobalt and Chromium particles we sought to test a novel Ceramic on Ceramic (CoC) bearing which may mitigate such problems. We set out to compare the behaviour of a novel ceramic femoral head component to a standard metal component in a hip resurfacing system after cemented implantation in a physiological warmed cadaveric model. Our first aim was to perform heat transfer analysis: To document time to, and extent of, maximum temperature change on the metal/ceramic surface and inside the resurfaced femoral head bone. Our second aim was to perform a dimensional analysis: To document any resulting deformation in the metal/ceramic femoral head bearing diameter during cementation.INTRODUCTION
AIM
The cup component of modern resurfacing systems are often coated creating a cementless press-fit fixation in the acetabulum based on surgical under-reaming, also enabling osseoconduction/integration. Due to the higher density of cortical bone along the antero-superior and postero-inferior regions of the acetabulum, the greatest forces occur between the anterior and posterior columns of the pelvis. This produces pinching of the implant that can result in deformation of the cup. Metal shell/modularpress-fit acetabular cups are susceptible to substantial deformation immediately after implantation. This deformation may affect the lubrication, producing point loading and high friction torques between the head and the cup that increase wear and may lead to head clamping and subsequent cup loosening. We sought to test a novel ceramic on ceramic (CoC) hip resurfacing system that should allay any concerns with the Adverse Reaction to Metal Debris associated with metal on metal (MoM) resurfacing devices. We sought to quantify the deformation of a novel CoC hip-resurfacing cup after implantation, using a standard surgical technique in a cadaveric model, and compare to the MoM standard. We also assessed if the design clearances proposed for this CoC hip resurfacing implant are compatible with the measured deformations, allowing for an adequate motion of the joint.INTRODUCTION
AIM
There is little information available to surgeons regarding how the lateral soft-tissue structures prevent instability in knees implanted with total knee arthroplasty (TKA). The aim of this study was to quantify the lateral soft-tissue contributions to stability following cruciate retaining (CR) TKA. Nine cadaveric knees with CR TKA implants (PFC Sigma; DePuy Synthes Joint Reconstruction) were tested in a robotic system (Fig. 1) at full extension, 30°, 60°, and 90° flexion angles. ±90 N anterior-posterior force, ±8 Nm varus-valgus and ±5 Nm internal-external torque were applied at each flexion angle. The anterolateral structures (ALS, including the iliotibial band, anterolateral ligament and anterolateral capsule), the lateral collateral ligament (LCL), the popliteus tendon complex (Pop T) and the posterior cruciate ligament (PCL) were then sequentially transected. After each transection the kinematics obtained from the original loads were replayed, and the decrease in force / moment equated to the relative contributions of each soft-tissue to stabilising the applied loads.Introduction
Methods
Arthroplasty requires an interdisciplinary multimodal approach with anaesthetists playing a key role; providing stable intra-operative conditions, allowing rapid patient recovery, optimising analgeisa and minimizing side-effects. The incidence of post-operative urinary retention (POUR) varies significantly in joint arthroplasty (10–84%). Current literature quotes lower doses of opioids have been shown to reduce POUR, however studies consistently show spinal opioids influence bladder function causing urinary retention. Existing literature fails to comment upon the rate of POUR following joint arthroplasty comparing intrathecal diamorphine against intrathecal local anaesthetic (ITLA) within a modern fast track arthroplasty system (FTA). A two-year (2009–11) retrospective analysis was conducted encompassing a multi-surgeon duel-centre review. Rates of POUR were compared when utilising ITLA and multimodal analgesia including local anaesthetic infiltration (LIA) (site A) against ITLA in combination with intrathecal diamorphine (site B) for joint arthroplasty under spinal analgesia. Outcomes were analysed using 30-day POUR rates coding data and cross-referenced against patient records. Information was collected on patient co-morbidity, age, gender, surgery duration and renal function. Patients were excluded for previous POUR, prostate pathology, postoperative PCA, and conversion to general anaesthetic.Background
Methods
To evaluate the volume of cases, causes of failure, complications in patients with a failed Thompson hemiarthroplasty. A retrospective review was undertaken between 2005–11, of all Thompson implant revised in the trust. Patients were identified by clinical coding. All case notes were reviewed. Data collection included patients demographic, time to revision, reason for revision, type of revision implant, surgical time and technique, transfusion, complications, HDU stay, mobility pre and post revision,Objective
Methods
