The primary stability of the cementless Oxford Unicompartmental Knee Replacement (OUKR) relies on interference fit (or press fit). Insufficient interference may cause implant loosening, whilst excessive interference could cause bone damage and fracture. The aim of this study was to identify the optimal interference fit by measuring the force required to seat the tibial component of the cementless OUKR (push-in force) and the force required to remove the component (pull-out force). Six cementless OUKR tibial components were implanted in 12 new slots prepared on blocks of solid polyurethane foam (20 pounds per cubic foot (PCF), Sawbones, Malmo, Sweden) with a range of interference of 0.1 mm to 1.9 mm using a Dartec materials testing machine HC10 (Zwick Ltd, Herefordshire, United Kingdom) . The experiment was repeated with cellular polyurethane foam (15 PCF), which is a more porous analogue for trabecular bone.Objectives
Materials and Methods
The objectives of this study were to compare postoperative pain, analgesia requirements, inpatient functional rehabilitation, time to hospital discharge, and complications in patients undergoing conventional jig-based unicompartmental knee arthroplasty (UKA) This prospective cohort study included 146 patients with symptomatic medial compartment knee osteoarthritis undergoing primary UKA performed by a single surgeon. This included 73 consecutive patients undergoing conventional jig-based mobile bearing UKA, followed by 73 consecutive patients receiving robotic-arm assisted fixed bearing UKA. All surgical procedures were performed using the standard medial parapatellar approach for UKA, and all patients underwent the same postoperative rehabilitation programme. Postoperative pain scores on the numerical rating scale and opiate analgesia consumption were recorded until discharge. Time to attainment of predefined functional rehabilitation outcomes, hospital discharge, and postoperative complications were recorded by independent observers.Aims
Patients and Methods
Posterior condylar offset (PCO) and posterior tibial slope (PTS) are critical factors in total knee arthroplasty (TKA). A computational simulation was performed to evaluate the biomechanical effect of PCO and PTS on cruciate retaining TKA. We generated a subject-specific computational model followed by the development of ± 1 mm, ± 2 mm and ± 3 mm PCO models in the posterior direction, and -3°, 0°, 3° and 6° PTS models with each of the PCO models. Using a validated finite element (FE) model, we investigated the influence of the changes in PCO and PTS on the contact stress in the patellar button and the forces on the posterior cruciate ligament (PCL), patellar tendon and quadriceps muscles under the deep knee-bend loading conditions.Objectives
Methods
The aims of this systematic review were to describe the quantity and methodological quality of meta-analyses in orthopaedic surgery published during the last 17 years. MEDLINE, EMBASE, and PubMed, between 1 January 2000 and 31 December 2016, were searched for meta-analyses in orthopaedic surgery dealing with at least one surgical intervention. Meta-analyses were included if the interventions involved a human muscle, ligament, bone or joint.Aims
Materials and Methods
The purpose of this study was to evaluate spinopelvic mechanics from standing and sitting positions in subjects with and without femoroacetabular impingement (FAI). We hypothesize that FAI patients will experience less flexion at the lumbar spine and more flexion at the hip whilst changing from standing to sitting positions than subjects without FAI. This increase in hip flexion may contribute to symptomatology in FAI. Male subjects were prospectively enrolled to the study (n = 20). Mean age was 31 years old (22 to 41). All underwent clinical examination, plain radiographs, and dynamic imaging using EOS. Subjects were categorized into three groups: non-FAI (no radiographic or clinical FAI or pain), asymptomatic FAI (radiographic and clinical FAI but no pain), and symptomatic FAI (patients with both pain and radiographic FAI). FAI was defined as internal rotation less than 15° and alpha angle greater than 60°. Subjects underwent standing and sitting radiographs in order to measure spine and femoroacetabular flexion.Aims
Patients and Methods
The objective of this study was to quantify the relative movement between the articular surfaces in the tibiotalar and subtalar joints during normal walking in asymptomatic individuals. 3D movement data of the ankle joint complex were acquired from 18 subjects using a biplanar fluoroscopic system and 3D-to-2D registration of bone models obtained from CT images. Surface relative velocity vectors (SRVVs) of the articular surfaces of the tibiotalar and subtalar joints were calculated. The relative movement of the articulating surfaces was quantified as the mean relative speed (RS) and synchronization index (SIENT) of the SRVVs.Objectives
Methods
Plating displaced proximal humeral fractures is associated with a high rate of screw perforation. Dynamization of the proximal screws might prevent these complications. The aim of this study was to develop and evaluate a new gliding screw concept for plating proximal humeral fractures biomechanically. Eight pairs of three-part humeral fractures were randomly assigned for pairwise instrumentation using either a prototype gliding plate or a standard PHILOS plate, and four pairs were fixed using the gliding plate with bone cement augmentation of its proximal screws. The specimens were cyclically tested under progressively increasing loading until perforation of a screw. Telescoping of a screw, varus tilting and screw migration were recorded using optical motion tracking.Aims
Methods
Positive ulnar variance is an established risk factor for idiopathic
ulnar impaction syndrome (UIS). However, not all patients with positive
ulnar variance develop symptomatic UIS and other factors, including
the morphology of the lunate, may be involved. The aim of this study
was to clarify the relationship between lunate morphology and idiopathic
UIS. A cohort of 95 patients with idiopathic UIS (UIS group) was compared
with 95 asymptomatic controls with positive ulnar variance. The
shape of the lunate was measured using the capitate-triquetrum distance
(CTD), ulnar coverage ratio (UCR), radiolunate distance and radiolunate
angle. The association of radiographic parameters and lunate types
with the development of UIS was investigated in univariable and
multivariable analyses. Receiver operating characteristic curves
were used to estimate a cutoff for any statistically significant
variables.Aims
Patients and Methods
The aim of this study was to assess hypertrophy of the extra-articular
tendon of the long head of biceps (LHB) in patients with a rotator
cuff tear. The study involved 638 shoulders in 334 patients (175 men, 159
women, mean age 62.6 years; 25 to 81) with unilateral symptomatic
rotator cuff tears. The cross-sectional area (CSA) of the LHB tendon
in the bicipital groove was measured pre-operatively in both shoulders
using ultrasound. There were 154 asymptomatic rotator cuff tears
in the contralateral shoulder. Comparisons were made between those
with a symptomatic tear, an asymptomatic tear and those with no
rotator cuff tear. In the affected shoulders, the CSAs were compared
in relation to the location and size of the rotator cuff tear. Aims
Patients and Methods
Stable fractures of the ankle can be safely treated
non-operatively. It is also gradually being recognised that the integrity
of the ‘medial column’ is essential for the stability of the fracture.
It is generally thought that bi- and tri-malleolar fractures are
unstable, as are pronation external rotation injuries resulting
in an isolated high fibular fracture (Weber type-C), where the deltoid
ligament is damaged or the medial malleolus fractured. However,
how best to identify unstable, isolated, trans-syndesmotic Weber
type-B supination external rotation (SER) fractures of the lateral
malleolus remains controversial. We provide a rationale as to how to classify SER distal fibular
fractures using weight-bearing radiographs, and how this can help
guide the management of these common injuries. Cite this article:
The aim of this retrospective study was to compare the functional
and radiological outcomes of bridge plating, screw fixation, and
a combination of both methods for the treatment of Lisfranc fracture
dislocations. A total of 108 patients were treated for a Lisfranc fracture
dislocation over a period of nine years. Of these, 38 underwent
transarticular screw fixation, 45 dorsal bridge plating, and 25
a combination technique. Injuries were assessed preoperatively according
to the Myerson classification system. The outcome measures included
the American Orthopaedic Foot and Ankle Society (AOFAS) score, the
validated Manchester Oxford Foot Questionnaire (MOXFQ) functional
tool, and the radiological Wilppula classification of anatomical
reduction.Aims
Patients and Methods
The purpose of this study was to evaluate the existing literature from 2005 to 2016 reporting on the efficacy of surgical management of patients with femoroacetabular impingement (FAI) secondary to slipped capital femoral epiphysis (SCFE). The electronic databases MEDLINE, EMBASE, and PubMed were searched and screened in duplicate. Data such as patient demographics, surgical technique, surgical outcomes and complications were retrieved from eligible studies.Objectives
Methods
There is not adequate evidence to establish whether external
fixation (EF) of pelvic fractures leads to a reduced mortality.
We used the Japan Trauma Data Bank database to identify isolated
unstable pelvic ring fractures to exclude the possibility of blood
loss from other injuries, and analyzed the effectiveness of EF on
mortality in this group of patients. This was a registry-based comparison of 1163 patients who had
been treated for an isolated unstable pelvic ring fracture with
(386 patients) or without (777 patients) EF. An isolated pelvic
ring fracture was defined by an Abbreviated Injury Score (AIS) for
other injuries of <
3. An unstable pelvic ring fracture was defined
as having an AIS ≥ 4. The primary outcome of this study was mortality.
A subgroup analysis was carried out for patients who required blood
transfusion within 24 hours of arrival in the Emergency Department
and those who had massive blood loss (AIS code: 852610.5). Propensity-score
matching was used to identify a cohort like the EF and non-EF groups.Aim
Patients and Methods
Loss of motion following spine segment fusion results in increased strain in the adjacent motion segments. However, to date, studies on the biomechanics of the cervical spine have not assessed the role of coupled motions in the lumbar spine. Accordingly, we investigated the biomechanics of the cervical spine following cervical fusion and lumbar fusion during simulated whiplash using a whole-human finite element (FE) model to simulate coupled motions of the spine. A previously validated FE model of the human body in the driver-occupant position was used to investigate cervical hyperextension injury. The cervical spine was subjected to simulated whiplash exposure in accordance with Euro NCAP (the European New Car Assessment Programme) testing using the whole human FE model. The coupled motions between the cervical spine and lumbar spine were assessed by evaluating the biomechanical effects of simulated cervical fusion and lumbar fusion.Objectives
Methods
