Patellofemoral complications are common after
total
Unicompartmental knee arthroplasty (UKA) is an alternative to total knee arthroplasty with isolated medial or lateral compartment osteoarthritis. However, polyethylene wear can significantly reduce the lifespan of UKA. Different bearing designs and materials for UKA have been developed to change the rate of polyethylene wear. Therefore, the objective of this study is to investigate the effect of insert conformity and material on the predicted wear in mobile-bearing UKA using a previously developed computational wear method. Two different designs were tested with the same femoral component under identical kinematic input: anatomy mimetic design (AMD) and conforming design inserts with different conformity levels. The insert materials were standard or crosslinked ultra-high-molecular-weight polyethylene (UHMWPE). We evaluated the contact pressure, contact area, wear rate, wear depth, and volumetric wear under gait cycle loading conditions.Objectives
Methods
We randomised 120 patients who were undergoing either primary total hip or
Continuous technical improvement in spinal surgical procedures, with the aim of enhancing patient outcomes, can be assisted by the deployment of advanced technologies including navigation, intraoperative CT imaging, and surgical robots. The latest generation of robotic surgical systems allows the simultaneous application of a range of digital features that provide the surgeon with an improved view of the surgical field, often through a narrow portal. There is emerging evidence that procedure-related complications and intraoperative blood loss can be reduced if the new technologies are used by appropriately trained surgeons. Acceptance of the role of surgical robots has increased in recent years among a number of surgical specialities including general surgery, neurosurgery, and orthopaedic surgeons performing major joint arthroplasty. However, ethical challenges have emerged with the rollout of these innovations, such as ensuring surgeon competence in the use of surgical robotics and avoiding financial conflicts of interest. Therefore, it is essential that trainees aspiring to become spinal surgeons as well as established spinal specialists should develop the necessary skills to use robotic technology safely and effectively and understand the ethical framework within which the technology is introduced. Traditional and more recently developed platforms exist to aid skill acquisition and surgical training which are described. The aim of this narrative review is to describe the role of surgical robotics in spinal surgery, describe measures of proficiency, and present the range of training platforms that institutions can use to ensure they employ confident spine surgeons adequately prepared for the era of robotic spinal surgery. Cite this article:
The role of computer-assisted surgery in maintaining the level of the joint in primary
To establish the utility of adding the laboratory-based synovial alpha-defensin immunoassay to the traditional diagnostic work-up of a prosthetic joint infection (PJI). A group of four physicians evaluated 158 consecutive patients who were worked up for PJI, of which 94 underwent revision arthroplasty. Each physician reviewed the diagnostic data and decided on the presence of PJI according to the 2014 Musculoskeletal Infection Society (MSIS) criteria (yes, no, or undetermined). Their initial randomized review of the available data before or after surgery was blinded to each alpha-defensin result and a subsequent randomized review was conducted with each result. Multilevel logistic regression analysis assessed the effect of having the alpha-defensin result on the ability to diagnose PJI. Alpha-defensin was correlated to the number of synovial white blood cells (WBCs) and percentage of polymorphonuclear cells (%PMN).Aims
Methods
Maquet's line passes from the centre of the femoral head to the centre of the body of the talus. The distance of this line from the centre of the knee on a long-leg radiograph provides the most accurate measure of coronal alignment. Malalignment causes abnormal forces which may lead to loosening after
Objectives. Lower limb muscle power is thought to influence outcome following
total
This pilot study tested the performance of a rapid assay for diagnosing prosthetic joint infection (PJI), which measures synovial fluid calprotectin from total hip and knee revision patients. A convenience series of 69 synovial fluid samples from revision patients at the Norfolk and Norwich University Hospital were collected intraoperatively (52 hips, 17 knees) and frozen. Synovial fluid calprotectin was measured retrospectively using a new commercially available lateral flow assay for PJI diagnosis (Lyfstone AS) and compared to International Consensus Meeting (ICM) 2018 criteria and clinical case review (ICM-CR) gold standards.Aims
Methods
The Unispacer knee system is a cobalt-chrome self-centring tibial hemiarthroplasty device for use in the treatment of isolated medial compartment osteoarthritis of the knee. The indications for use are similar to those for high tibial osteotomy, but insertion does not require bone cuts or component fixation, and does not compromise future
Systemic emboli released during total knee replacement have been implicated as a cause of peri-operative morbidity and neurological dysfunction. We undertook a prospective, double-blind, randomised study to compare the cardiac embolic load sustained during computer-assisted and conventional, intramedullary-aligned, total knee replacement, as measured by transoesophageal echocardiography. There were 26 consecutive procedures performed by a single surgeon at a single hospital. The embolic load was scored using the modified Mayo grading system for echogenic emboli. Fourteen patients undergoing computer-assisted total knee replacement had a mean embolic score of 4.89 (3 to 7) and 12 undergoing conventional total knee replacement had a mean embolic score of 6.15 (4 to 8) on release of the tourniquet. Comparison of the groups using a two-tailed t-test confirmed a highly significant difference (p = 0.004). This study demonstrates that computer-assisted
We identified 148 patients who had undergone a revision total knee replacement using a single implant system between 1990 and 2000. Of these 18 patients had died, six had developed a peri-prosthetic fracture and ten had incomplete records or radiographs. This left 114 with prospectively-collected radiographs and Bristol knee scores available for study. The height of the joint line before and after revision total knee replacement was measured and classified as either restored to within 5 mm of the pre-operative height or elevated if it was positioned more than 5 mm above the pre-operative height. The joint line was elevated in 41 knees (36%) and restored in 73 (64%). Revision surgery significantly improved the mean Bristol knee score from 41.1 (. sd. 15.9) pre-operatively to 80.5 (. sd. 15) post-operatively (p <
0.001). At one year post-operatively both the total Bristol knee score and its functional component were significantly better in the restored group than in the elevated group (p <
0.01). Overall, revision from a unicondylar
We have studied the long-term outcome of 408 primary medial St George Sled unicompartmental arthroplasties of the knee and 531 primary Kinematic total knee arthroplasties using survivorship analysis. The operations were performed by a number of surgeons under the supervision of two consultants at one orthopaedic centre. Prospective clinical assessment was carried out before and at 2, 5, 8, 10, 12 and 15 years after operation. Failure was defined as follows: revision or removal of the implant; the presence of moderate or severe pain; or ‘worst-case’ with all patients lost to follow-up. Cumulative survival rates at ten years were calculated using life tables. The follow-up rate was 97%. At ten years, 25 medial sled arthroplasties and 20 Kinematic
Second-generation metal-on-metal (MoM) articulations in total hip arthroplasty (THA) were introduced in order to reduce wear-related complications. The current study reports on the serum cobalt levels and the clinical outcome at a minimum of 20 years following THA with a MoM (Metasul) or a ceramic-on-polyethylene (CoP) bearing. The present study provides an update of a previously published prospective randomized controlled study, evaluating the serum cobalt levels of a consecutive cohort of 100 patients following THA with a MoM or a CoP articulation. A total of 31 patients were available for clinical and radiological follow-up examination. After exclusion of 11 patients because of other cobalt-containing implants, 20 patients (MoM (n = 11); CoP (n = 9)) with a mean age of 69 years (42 to 97) were analyzed. Serum cobalt levels were compared to serum cobalt levels five years out of surgery.Aims
Methods
We scanned 25 left knees in healthy human subjects
using MRI. Multiplanar reconstruction software was used to take
measurements of the inferior and posterior facets of the femoral
condyles and the trochlea. A ‘basic circle’ can be defined which, in the sagittal plane,
fits the posterior and inferior facets of the lateral condyle, the
posterior facet of the medial condyle and the floor of the groove
of the trochlea. It also approximately fits both condyles in the
coronal plane (inferior facets) and the axial plane (posterior facets).
The circle fitting the inferior facet of the medial condyle in the
sagittal plane was consistently 35% larger than the other circles
and was termed the ‘medial inferior circle’. There were strong correlations
between the radii of the circles, the relative positions of the
centres of the condyles, the width of the condyles, the total knee
width and skeletal measurements including height. There was poor
correlation between the radii of the circles and the position of
the trochlea relative to the condyles. In summary, the condyles are approximately spherical except for
the inferior facet medially, which has a larger radius in the sagittal
plane. The size and position of the condyles are consistent and
change with the size of the person. However, the position of the
trochlea is variable even though its radius is similar to that of
the condyles. This information has implications for understanding
anterior knee pain and for the design of