Aims
Materials and Methods
The optimal correction of the weight bearing line during High Tibial Osteotomy has not been determined. We used finite element modelling to simulate the effect that increasing opening wedge HTO has on the distribution of stress and pressure through the knee joint during normal gait. Subject-specific models were developed by combining geometry from 7T MRI scans and applied joint loads from ground reaction forces measured during level walking. Baseline stresses and pressures on the articulating proximal tibial cartilage and menisci were calculated. Progressive osteotomies were then simulated to shift the weight-bearing line from the native alignment towards/into the lateral compartment (between 40 – 80% of medial-lateral tibial width). Changes in calculated stresses and pressures were recorded. Both stress and pressure decreased in the medial compartment and increased in the lateral compartment as increasingly valgus osteotomies were simulated. The models demonstrated a consistent “safe zone” for weight bearing line position at 50%-65% medial-lateral tibial width, outside of which compartment stresses and pressures substantial increased. This study suggests a safe correction zone within which a medial opening wedge HTO can be performed correcting the WBL to 55% medio-lateral width of the tibia.
Endoprosthetic replacement (EPR) is an available option for the management of massive bone loss around failed knee implants. The aim of this study was to determine the results of knee EPRs performed for non-tumour indications. Since 2007, 85 EPRs were performed for in a single tertiary centre by seven surgeons. Mean age at surgery was 73.5 years (range:35–95) with infection as the most common indication (49%), followed by aseptic loosening (18%), complex primary replacement (16%), fracture (15%) and mechanical failure (2%). Mean follow up was 4 years (range:1–9). Functional outcome was determined using the Oxford Knee Score (OKS). At follow-up, 21 patients were deceased and 2 lost to follow-up. Complication rate was 19%. Of the 7 infected cases, 6 were treated with DAIR (debridement, antibiotics, and implant retention) and one underwent above knee amputation. Four of the patients undergoing DAIR were cleared of infection and 2 are on long-term antibiotics. Accounting for implant revision, loss to follow-up and those on long-term antibiotics as failures, 5-year survival was 89% with an average OKS of 25 (SD=10). This mid-term study shows that distal femur EPR is a valuable option for the increasing burden of complex revision knee surgery
Next-generation sequencing (NGS) is a well-established technique for amplification and sequencing of DNA and has recently gained much attention in many fields of medicine. Our aim was to evaluate the ability of NGS in identifying the causative organism(s) in patients with periprosthetic joint infection (PJI). In this prospective study samples were collected from 78 revision total hip arthroplasties. Synovial fluid, deep tissue and swabs were obtained at the time of surgery and shipped to the laboratory for NGS analysis. Deep tissue specimens were also sent to the institutional lab for culture. PJI was diagnosed using the Musculoskeletal infection society (MSIS) definition of PJI. Thirty-four revisions were considered infected; culture was positive in 25 of these (25/34, 73.5%), while NGS was positive in 26 (26/34, 76.4%). Among the positive cultures, complete concordance between NGS and culture in 21 cases (21/25, 84.0%). 4 cases were discordant. Among these cases, 3 cases were culture-positive and NGS-negative, while 1 was both positive on NGS and culture for disparate organisms. Among the 9 cases of culture-negative PJI(CN-PJI), NGS was able to identify an organism in 4 cases (4/9, 44.4%). The remaining 5 cases were negative on both NGS and culture (5/9, 55.6%). Forty-four revisions were considered to be aseptic; NGS exclusively identified microbes in 7 of 44 “aseptic” revisions (15.9%) and culture exclusively isolated an organism in 3 of 44 cases (6.8%). Both NGS and culture were positive in 1 of case however the result was discordant. The remaining cases (33/44, 75.0%) were both NGS and culture negative. NGS detected several organisms in most positive samples, with a greater number of organisms detected in aseptic compared to septic cases (7 vs. 3.7, respectively). NGS may be a promising technique for identifying the infecting organism in PJI. Our findings suggest that some cases of PJI may be polymicrobial that escape detection using conventional culture.
To assess the influence of route of antibiotic administration on patient-reported outcome measures (PROMS) of individuals treated for hip and knee infections in the OVIVA multi-centre randomised controlled trial. This study was designed to determine whether oral antibiotic therapy is non-inferior to intravenous (IV) therapy when given for the first six weeks of treatment for bone and joint infections. Of the 1054 participants recruited from 26 centres, 462 were treated for periprosthetic or native joint infections of the hip or knee. There were 243 participants in the IV antibiotic cohort and 219 in the oral cohort. Functional outcome was determined at baseline through to one year using the Oxford Hip/Knee Score (OHS/OKS) as joint-specific measures (0 the worse and 48 the best). An adjusted quantile regression model was used to compare functional outcome scores.Aim
Method
Advocates of Debridement-Antibiotics-and-Implant-Retention (DAIR) in hip peri-prosthetic joint infection (PJI) argue that a procedure not disturbing a sound prosthesis-bone interface is likely to lead to better survival and functional outcome compared to revision. However, no evidence supports this. This case-control study's aims were to compare outcome of DAIRs for infected 1° total hip arthroplasty (THA) with outcomes following 1° THA and 2-stage revisions of infected 1° THAs. We retrospectively reviewed all DAIRs, performed for confirmed infected 1° THR (DAIR-Group, n=80), in our unit between 1997–2013. Data recorded included patient demographics, medical history, type of surgery and organism identified. Outcome measures included complications, mortality, implant survivorship and functional outcome using the Oxford Hip Score (OHS). Outcome was compared with 2 control groups matched for gender and age; a cohort of 1° THA (1°-THA-Group, n=120) and a cohort of 2-stage revisions for infection (2-Stage-Revision-Group, n=66).Aim
Method
The burden of peri-prosthetic joint infection (PJI) following hip and knee surgery is increasing. Endoprosthetic replacement (EPR) is an option for management of massive bone loss resulting from infection around failed lower limb implants. To determine clinical outcome of EPRs for treatment of PJI around the hip and knee joint.Introduction
Aims
A possible solution for the management of proximal femoral bone
loss is a modular femoral endoprosthesis (EPR). Although the outcome
of EPRs in tumour surgery has been well described, the outcome of
their use in revision hip surgery has received less attention. The
aim of this study was to describe the outcome of using EPR for non-neoplastic
indications. A retrospective review of 79 patients who underwent 80 EPRs for
non-neoplastic indications was performed, including the rates of
complication and survival and the mean Oxford Hip Scores (OHS),
at a mean of five years post-operatively. The mean age at the time
of surgery was 69 years (28 to 93) and the mean number of previous operations
on the hip was 2.4 (0 to 17). The most common indications for EPR
implantation were periprosthetic joint infection (PJI) (n = 40),
periprosthetic fracture (n = 12) and failed osteosynthesis of a
proximal femoral fracture or complex trauma (n = 11).Objectives
Methods
The aim of this to study was to compare the previously unreported
long-term survival outcome of the Oxford medial unicompartmental
knee arthroplasty (UKA) performed by trainee surgeons and consultants. We therefore identified a previously unreported cohort of 1084
knees in 947 patients who had a UKA inserted for anteromedial knee
arthritis by consultants and surgeons in training, at a tertiary
arthroplasty centre and performed survival analysis on the group
with revision as the endpoint.Aims
Patients and Methods
The management of proximal femoral bone loss is a significant challenge in revision hip arthroplasty. A possible solution is the use of a modular proximal femur endoprosthesis (EPR). Although the survivorship and functional outcome of megaprostheses used in tumour surgery has been well described, outcome of EPRs used in revision hip surgery has received less attention. The aim of this study was to determine the 5-year outcome following proximal femur EPR and determine factors that influence it. This was a retrospective consecutive case series of all EPRs (n=80) performed for non-neoplastic indications, by 6 surgeons, in our tertiary referral centre, between 2005–2014. Patient demographics and relevant clinical details were determined from notes. The most common indications for the use of EPRs included infection (n=40), peri-prosthetic fracture (n=12) and failed osteosynthesis of proximal femoral fractures/complex trauma (n=11). Outcome measures included complication and re-operation rates, implant survival and assessment of functional outcome using the Oxford-Hip-Score (OHS). The mean age at surgery was 69 years and mean follow-up was 4 (0 – 11) years. The mean number of previous hip operations was 2.4 (range: 0 – 17). Twenty-five patients sustained a complication (31%), the most common being infection (n=9) and dislocation (n=4). By follow-up, further surgery was required in 18 (22%) hips, 9 of which were EPR revisions. 5-yr implant survivorship was 87% (95%CI: 76 – 98%). Mean OHS was 28 (range: 4 – 48). Inferior survival and outcome were seen in EPRs performed for the treatment of infection. Infection eradication was achieved in 34/41 with the index EPR procedure and in 40/41 hips by follow-up. Limb salvage was achieved in all cases and acceptable complication- and re-operation rates were seen. EPRs for periprosthetic fractures and failed osteosynthesis had best outcome. We recommend the continued use of proximal femur EPR in complex revision surgery.
Despite being one of the most common orthopaedic
operations, it is still not known how many arthroscopies of the knee
must be performed during training in order to develop the skills
required to become a Consultant. A total of 54 subjects were divided
into five groups according to clinical experience: Novices (n =
10), Junior trainees (n = 10), Registrars (n = 18), Fellows (n =
10) and Consultants (n = 6). After viewing an instructional presentation,
each subject performed a simple diagnostic arthroscopy of the knee
on a simulator with visualisation and probing of ten anatomical
landmarks. Performance was assessed using a validated global rating
scale (GRS). Comparisons were made against clinical experience measured
by the number of arthroscopies which had been undertaken, and ROC
curve analysis was used to determine the number of procedures needed
to perform at the level of the Consultants. There were marked differences between the groups. There was significant
improvement in performance with increasing experience (p <
0.05). ROC curve analysis identified that approximately 170 procedures
were required to achieve the level of skills of a Consultant. We suggest that this approach to identify what represents the
level of surgical skills of a Consultant should be used more widely
so that standards of training are maintained through the development
of an evidenced-based curriculum. Cite this article:
Current work-hour restrictions and cost pressures have highlighted the limitations of apprenticeship-based learning, and led to the development of alternative methods to improve the skills of orthopaedic trainees outside of the clinical environment. These methods include using synthetic bones and simulators in the laboratory setting. Educational theory highlights the importance of context for effective learning, yet full-immersion simulation facilities are prohibitively expensive. This study explored the concept of contextualised training day in trauma & orthopaedics. Fifteen novice surgeons provided feedback after completing three teaching modules: OSCE-style Problem-based Learning of Orthopaedic Trauma in the Fracture Clinic Setting, utilising an actor and radiographs to teach history, examination, diagnostic and management skills The positioning, preparing and draping of a patient, and Examination under anaesthesia (EUA) for arthroscopic knee surgery, utilising an operating table and theatre equipment to teach procedural and examination skills Simulator based training for diagnostic shoulder and knee arthroscopy; and Bankart repair, utilising arthroscopic stack and synthetic joint models to develop arthroscopic motor skill and procedural knowledgeIntroduction
Methods
Restrictions placed on the working hours of doctors have led to increasing time-pressures on surgical training. Consequently, there has been growing interest in developing new techniques to teach and assess technical skills. The primary aim of this study was to determine whether a novel set of visual parameters assessing visuospatial ability, fine motor dexterity and gaze control could objectively distinguish between varying levels of arthroscopic experience. The secondary aim was to evaluate the correlations between these new parameters and previously established technical skill assessment methods. 27 subjects were divided into a “novice” group (n=7), “trainee” group (n=15) and expert group (n=5) based on previous arthroscopic experience. All subjects performed a diagnostic knee arthroscopy task on a simulator. Their performance was assessed using new simple visual parameters that included “prevalence of instrument loss,” “triangulation time” and “prevalence of look downs”. In addition, performance was also evaluated using previously validated technical skill assessment methods (a global rating scale and motion analysis).Introduction
Methods
Motion analysis is a validated method of assessing technical dexterity within surgical skills centers. A more accessible and cost-effective method of skills assessment is to use a global rating scale (GRS). We aimed to perform a validation experiment to compare an arthroscopic GRS against motion analysis for monitoring orthopaedic trainees learning simulated arthroscopic meniscal repairs. An arthroscopic meniscal repair task on a knee simulator was set up in a bioskills laboratory. Nineteen orthopaedic trainees with no experience of meniscal repair were recruited and their performance assessed whilst undertaking a standardized meniscal repair on 12 occasions. An arthroscopic GRS, assessing parameters such as “depth perception,” “bimanual dexterity,” “instrument handling,” and “final product analysis” was used to evaluate technical skill. Performance was assessed blindly by watching video recordings of the arthroscopic tasks. Dexterity analysis was performed using a motion analysis tracking system which measured “time taken,” “total path length of the subject's hands,” and “number of hand movements”.Introduction
Methods
Technical skill is an essential domain of surgical competency. Arthroscopic surgery forms a particularly challenging subset of these skills. The innate ability to acquire these skills is not fully understood. The aim of this study was to investigate the innate arthroscopic skills and learning curve patterns of medical students - our future surgeons. Two arthroscopic tasks (one shoulder and one knee) were set up in a bioskills laboratory to represent core skills required for arthroscopic training. Twenty medical students with no previous arthroscopic surgery experience were recruited and their performance assessed whilst undertaking each task on 30 occasions. The primary outcome variable was success or failure. Individuals were assessed as ‘competent’ if they stabilised their learning curve within 20 episodes. The secondary outcome measure was an objective assessment of technical dexterity using a validated Motion Analysis system (time taken to complete tasks, total path length of the subject's hands, and number of hand movements).Background
Methods
The ability to learn arthroscopic surgery is an important aspect of modern day orthopaedic surgery. Knowing that variation in innate ability exists amongst medical students, the aim of this study was to investigate the effect of training on the arthroscopic surgical performance of our future orthopaedic surgeons (medical students). Two arthroscopic tasks (one shoulder and one knee) were set up in a bioskills laboratory to represent core skills required for arthroscopic training. Thirty three medical students with no previous arthroscopic surgery experience were randomised to a ‘Trained’ (n=16) and ‘Non-trained’ (n=17) cohort. Both groups watched an instructional video. The Trained cohort also received specific training on the tasks prior to their first episode. Thirty episodes of each task were then undertaken. The primary outcome variable was success or failure. Individuals were assessed as ‘competent’ if they stabilised their learning curve within 20 episodes. The secondary outcome measure was an objective assessment of technical dexterity using a validated Motion Analysis system (time taken to complete tasks, total path length of the subject's hands, and number of hand movements).Background
Methods
Rheumatology and Musculoskeletal Sciences, NIHR Biomedical Research Unit, University of Oxford and the Nuffield Orthopaedic Hospital, Oxford The aim of this study was to use motion analysis to objectively study the learning curve of surgical trainees performing arthroscopic meniscal repair on a training model in a skills laboratory. With improving technology and an appreciation of its likely chondroprotective effects, meniscal repair surgery is becoming more common. It remains a difficult procedure and is not routinely learnt during surgical training.Purpose
Background
The aim of this study was to investigate the
effect of training on the arthroscopic performance of a group of
medical students and to determine whether all students could be
trained to competence. Thirty-three medical students with no previous
experience of arthroscopy were randomised to a ‘Trained’ or an ‘Untrained’
cohort. They were required to carry out 30 episodes of two simulated
arthroscopic tasks (one shoulder and one knee). The primary outcome variable
was task success at each episode. Individuals achieved competence
when their learning curve stabilised. The secondary outcome was
technical dexterity, assessed objectively using a validated motion
analysis system. Six subjects in the ‘Untrained’ cohort failed to
achieve competence in the shoulder task, compared with one in the ‘Trained’
cohort. During the knee task, two subjects in each cohort failed
to achieve competence. Based on the objective motion analysis parameters,
the ‘Trained’ cohort performed better on the shoulder task (p <
0.05) but there was no significant difference for the knee task
(p >
0.05). Although