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Up to 20% of patients are not satisfied with the outcome following total knee replacement (TKR), but little is known about the predictors of this dissatisfaction. This study investigated the pre- and post-operative predictors of dissatisfaction in a large cohort of patients undergoing TKR. We assessed 1217 consecutive patients undergoing TKR between 2006 and 2008 both preoperatively and six months after surgery, using the Short-form (SF)-12 health questionnaire and the Oxford Knee Score.
Detailed co-morbidity information was also gathered. Satisfaction was measured at one year and 18.6% (226 of 1217) of patients were unsure or dissatisfied with their replacement, 81.4% (911 of 1217) were satisfied or very satisfied. Multivariate regression analysis was performed to identify independent predictors of dissatisfaction. Significant (p < 0.001) predictors of dissatisfaction at one year included the pre-operative SF-12 mental component score, the co-morbidities of depression and pain in other joints, and the six-month SF-12 score. The most significant independent predictor of dissatisfaction at 1 year was poor improvement in Oxford Knee Score pain element at 6 months. Patient expectations were highly correlated with satisfaction.
Satisfaction following TKR is multifactorial. Managing patient expectations and mental health may reduce dissatisfaction rates. However, the most significant predictor of dissatisfaction is a painful total knee replacement.
Purpose
To establish the reliability of reporting and recording revision hip and knee arthroplasties by comparing data in the National Joint Registry (NJR), Hospital Episode Statistics (HES) and our local theatre records.
Methods
The paper theatre registers for all orthopaedic theatres in the Royal Derby Hospitals NHS Trust were examined for details of revision hip and knee replacements carried out in 2007 and 2008. This was then cross-checked and merged with the local electronic theatre data to obtain a definitive local record of all revision hip and knee arthroplasties. Data for the same period was requested from the NJR and HES and these data were checked against our definitive local record for discrepancies. The HES codes used were the same codes used to compile the recent NJR annual reports.
Purpose of the Study
To identify trends in patient satisfaction of their knee arthroplasty, total and unicompartmental, one year post primary knee arthroplasty surgery, with reference to age, gender and primary diagnosis, from 1990 to 2008.
Methods & Results
The Trent Arthroplasty Register was established in 1990 to collect prospective data on knee arthroplasty surgery Data has been recorded relating to 48,929 knee arthroplasties in the period 1990-2008. Self-administered questionnaires were mailed to patients 1 year after their surgery. This PROMS data has been analysed to identify trends in 25,521 patients
62% (24,648) of knee arthroplasties were performed for osteoarthritis and 32% (1,233) for rheumatoid arthritis. 83.6% of osteoarthritic patients (20,244) were satisfied with their knee 1 yr post surgery, 8.5% (2055) unsure and 7.9% dissatisfied. Comparable figures for patients with rheumatoid arthritis were 81.3% (1,028) satisfied, 10.3% (130) unsure and 8.4% dissatisfied. Overall, there was no significant difference in satisfaction rates between different diagnostic groups of patients. In osteoarthritic patients, satisfaction rates have remained the same throughout the last 18 years, in different time periods. The satisfaction rate was 83.2% for the period 1990-1994, 80.9% for 1995-1999, 86.5% for 2000-2004 and 84.1% for 2005-2007. There was no statistically significant difference between the levels of satisfaction for these time periods. The age of the patient did not affect the satisfaction rate.
The aim of this study was to explore the pre-operative predictors of the function component of the WOMAC one year after total knee arthroplasty (TKA) using a hierarchical regression model.
The pre-operative and one year post-operative results of 71 patients with knee osteoarthritis who underwent TKA were analysed. First the correlation between the post-operative function component of the WOMAC and a range of pre-operative measures were calculated to determine the independent variables for the hierarchical regression model. Independent pre-operative measures which showed a significant correlation with post-operative function were then entered in the model. Pre-operative measures were divided into three types according to International Classification of Health: (i) Personal characteristics, (ii) body structures and function and (iii) Psychosocial variables.
The following pre-operative measures were correlated with post-operative function: Knee flexion (r=-0.254), extensor strength (r=-0.338), flexor strength (r=-0.257), mental health component of the SF36 (r=-0.304), Tampa scale (fear of movement), (r=0.261), the sense of helplessness due to pain (r=0.264) and Stanford arthritis Self-Efficacy Pain Scale (r=-0.343). This scale is a measure of the person's belief in their capability to cope with their arthritis pain. The higher the score the better the person's self-efficacy.
Only independent pre-operative measures were entered in the models. In step 0, we controlled for age and Body Mass Index (BMI), in step 1 we entered knee flexion and extensor strength (model 1) and in step 2 Self-Efficacy was entered in the model (model2). In model1 extensor strength was a significant predictor of post-operative function (beta =-0.242, p=0.028). In the final model (model3) pre-operative extensor strength (beta =-0.242, p=0.07) and Self-Efficacy (beta -0.266, p=0.046) were the strongest predictors of post-operative function.
Conclusions
We found that pre-operative muscle strength and psychosocial measures such as the perceived ability to cope with the effects of arthritis pain (Pain Self-Efficacy) were the most meaningful predictors of outcome one year after total knee arthroplasty.
Aim
We aim to compare revision rates and functional outcome scores in between two contemporary total knee arthoplasty systems.
Methods
A search was carried out of a prospectively maintained outcomes database to identify all patients receiving total knee replacement (TKR) in the department between 2005 and 2006, when evaluation of different knee arthroplasty systems was being undertaken. Data on the first 93 consecutive patients receiving a Scorpio (Stryker, Allendale, NJ) implant and the first 93 consecutively receiving a PFC (DePuy, Warsaw, IN) implant were reviewed. Four year revision rates and functional scores were recorded.
PURPOSE OF STUDY
Periprosthetic fractures after total knee arthroplasty is a potentially serious and challenging complication and the incidence is continuously rising. The purpose of this study was to analyse the prevalence and analyse effectiveness of the various treatment methods for management of periprosthetic fracture of the distal femur after total knee arthroplasty, and to determine the clinical and radiographic results of patients following surgical treatment of these injuries.
METHODS
We reviewed all patients with periprosthetic fractures after total knee arthroplasty treated surgically between 2003 and 2008 from the prospective hospital database. Medical and radiographic records were reviewed for patient characteristics, fracture characteristics, implant details, healing, and complications.
Antero-posterior and lateral radiographs were reviewed at the time of admission, post-operatively and at follow up visits. Fractures were classified according to the Lewis and Rorabeck, Orthopaedic Trauma Association and the methods of Su and DeWal.
Introduction
A common complication whilst harvesting the hamstring tendon in ACL reconstruction is injury to the infra-patellar branch of the saphenous nerve (IPBSN), resulting in altered sensation to the anterior and lateral aspects of the knee and leg.
Aim
The aim of this study was to understand the course of IPBSN in relation to tendon harvest in ACL reconstruction.
This study was performed to evaluate the results of transphyseal anterior cruciate ligament (ACL) reconstruction in children with open physes.
Between 2001 and 2009, 31 knees in 29 patients with a mean age of 14.1 years (10-16) underwent transphyseal, arthroscopic ACL reconstruction using an autogenous four-strand hamstrings graft. The technique was identical to that used in the adult population in our unit, except that care was taken to ensure fixation did not cross the physes. The patients were followed up to the point of physeal closure at skeletal maturity. The mean length of follow up was 25 months. The primary outcome measure was graft survival. Functional outcome was measured using Lysolm scores, International Knee Documentation Committee (IKDC) scores and the Tegner activity scale. Post-operative clinical examination and radiological findings were also recorded.
There were two cases of re-rupture following a further sports injury, one 12 months post-operative and one at six years. Both patients later had successful revision ACL reconstructive surgery. The re-rupture rate in this case series was 6%. Two patients underwent repair of a concomitant lateral meniscal tear at the time of surgery. The mean post-operative Lysolm score was 88 and the mean IKDC score was 88.1. The mean Tegner activity scale was 7.95. There was no evidence of growth disturbance radiologically or leg length inequality clinically. There was one case of deep infection which was successfully treated with two subsequent arthroscopic washouts.
This study demonstrates that transphyseal arthroscopic ACL reconstruction using hamstrings graft and an ‘adult’ technique, in skeletally immature patients, provides good functional outcomes, has a low revision rate and is not associated with physeal growth arrest or disturbance.
The early surgical management of the anterior cruciate ligament (ACL) tears in children remains controversial. The argument for nonoperative treatment is driven by concerns about the risk of growth arrest caused by a transphyseal procedure. On the other hand, early surgical reconstruction is favoured because of poor compliance with conservative treatment and increased risk of secondary damage due to instability. This paper reports a series of 39 very young children who had an ACL reconstruction using a transphyseal procedure with a hamstring graft. Patients were followed to skeletal maturity or for a minimum of three years. Only those patients with either a chronological age less than 14 years or with a Tanner stage of 1 and 2 of puberty were included in the study. Thirty children were Tanner 1 or 2 and nine were Tanner 3-4 but were younger than 14. The mean age at operation was 12.2 years (Range 9.5-14.2, Median 12.4). The mean follow up was 60.7 months (range 36-129, median: 51) months. Thirty four patients had attained skeletal maturity at the last follow up. The mean Lysholm score improved from 72.4 pre-operatively to 95.86 postoperatively (p<0.0001). The mean Tegner activity scale was 4.23 after injury and it improved to 7.52 after operation (p<0.0001)) which was a reasonable comparison to the pre- injury score of 8.0. One patient had a mild valgus deformity with no functional disturbance. No other growth related abnormalities including limb length discrepancy were noted. There has been one re-rupture but all others had good or excellent outcome. This is one of the largest series reporting the long term results of ACL reconstruction in very young children. Most other studies include children up to the age of 16. Based on our results we can conclude that transphyseal ACL reconstruction modified for very young patients is a safe procedure.
Purpose
The purpose of this study was to determine whether intra-operative identification of osseous ridge anatomy (lateral intercondylar “residents” ridge and lateral bifurcate ridge) could be used to reliably define and reconstruct individuals' native femoral ACL attachments in both single-bundle (SB) and double-bundle (DB) cases.
Methods
Pre-and Post-operative 3D, surface rendered, CT reconstructions of the lateral intercondylar notch were obtained for 15 patients undergoing ACL reconstruction (11 Single bundle, 4 Double-bundle or Isolated bundle augmentations). Morphology of native ACL femoral attachment was defined from ridge anatomy on the pre-operative scans. Centre's of the ACL attachment, AM and PL bundles were recorded using the Bernard grid and Amis' circle methods. During reconstruction soft tissue was carefully removed from the lateral notch wall with RF coblation to preserve and visualise osseous ridge anatomy. For SB reconstructions the femoral tunnel was sited centrally on the lateral bifurcate ridge, equidistant between the lateral intercondylar ridge and posterior cartilage margin. For DB reconstructions tunnels were located either side of the bifurcate ridge, leaving a 2mm bony bridge. Post-operative 3D CTs were obtained within 6 weeks post-op to correlate tunnel positions with pre-op native morphology.
Introduction
Unlike the NJR, no surgeon driven national database currently exists for ligament surgery in the UK and therefore information on outcome and adverse event is limited to case series.
Methods
Prospectively collected Hospital episode statistics (HES) data for England was analysed so as to determine national rates of 90-day symptomatic deep venous thrombosis (DVT), pulmonary thromboembolism (PTE) rate, significant wound infection and 30-day readmission rates with cause following anterior cruciate ligament (ACL) reconstruction. This diagnostic and operative codes information is routinely collected on every patient admitted to hospital in England NHS.
Objective
To compare the clinical outcomes of bone-patellar tendon-bone (BTB) allografts sterilised through a novel sterilisation system with aseptically processed BTB allografts for Anterior Cruciate Ligament (ACL) reconstruction. The following hypotheses were also tested: (1) the cumulative score of the IKDC is not significantly different in the sterilised treatment group than in the aseptic control group, (2) the proportion of normal laxity in patients, as measured by the KT 2000 arthrometer, is not significantly different in the sterilised group than in the aseptic control group.
Methods
A total of 76 patients undergoing ACL reconstruction were randomised into one of two intervention groups, BioCleanse¯-sterilised or Aseptic BTB allografts, at 6 independent investigation sites. Post-op examiners and patients were blinded to graft type. Patients were evaluated at 6 months (44 of the 76), 12 months (20 of the 76), and 24 months (27 of the 76) with KT-2000, IKDC scores, and Flexion and Extension Range of Motion (ROM) analysis. Inclusion criteria included an acute, isolated, unilateral ACL tear and exclusion criteria included prior ACL injury, multiligament reconstruction, and signs of degenerative joint disease.
Aim
To assess the ten year subjective knee function and activity level following four-strand semitendinosis and gracilis (STG) anterior cruciate ligament reconstruction.
Methods
86 patients underwent anterior cruciate reconstruction by two knee surgeons in the year 1999. 80 patients meet the inclusion criteria of STG reconstruction by a standard operative technique. Patient evaluation was by completion of a Lysholm Knee Score and Tegner Activity Level Scale at a minimum of ten years from reconstructive surgery. This was by initial postal questionnaire and subsequent telephone follow-up.
Purpose
The aim of the present study was to investigate the relationship between generalised ligament laxity and requirement for revision ACL reconstruction.
Materials and methods
126 patients undergoing primary ACL reconstruction were included in the study along with 35 patients undergoing revision ACL surgery. 62 patients without any knee ligament injury formed an age and sex matched the control group.
The Beighton score was used to quantify the ligamentous laxity in all cases with a score more than 4 classified as having generalised ligamentous laxity. The revision ACL patients were evaluated to identify technical errors at the time of the primary procedure or subsequent traumatic injury that could have contributed to primary graft failure.
This study evaluates high power low frequency ultrasound transmitted via a flat vibrating probe tip as an alternative technology for meniscal debridement in the knee. A limitation of this technology is thermal damage in residual meniscal tissue.
An experimental force controlled testing rig was constructed using a 20kHz ultrasonic probe suspended vertically from a load cell. Ex-vivo bovine meniscus samples were harvested from knee joints and cut into uniform 16mm discs. Effect of variation in force (2.5-4.5N) and amplitude of distal tip displacement (242-494μm peak-peak) settings on tissue removal rate (TRR) and penetration rate (PR) was analysed. Temperature elevation in the residual meniscus was measured by embedded thermocouples and residual meniscus histological analysis. The experiment was designed using a response surface quadratic model with input variables treated as continuous, using Design-Expert v.8.0 (Stat-Ease Inc., Minneapolis, MN). Statistical analysis was conducted using PASW Statistics v.18.0 (IBM SPSS Inc., Chicago, IL).
As either force or amplitude increases, there is a linear increase in TRR (Mean±SD: 0.9±0.4 to 11.2±4.9mg/s). A corresponding increase is observed in PR (Mean±SD: 0.08±0.04 to 0.73±0.18mm/s). Maximum mean temperatures of 84.6±12.1°C and 52.3±10.9°C were recorded in residual tissue at 2mm and 4mm from the ultrasound probe-tissue interface. Minimum depth of the zone of thermal alteration in residual tissue was 177.4μm.
There is an inverse relationship between both amplitude and force, and temperature elevation, with higher amplitude and force settings resulting in less thermal damage. Ultrasonic debridement shows comparable thermal damage to existing meniscal debridement technologies.
Purpose
To assess performance of a polyurethane scaffold designed to facilitate regrowth of tissue after irreparable partial meniscus tissue loss.
Methods
Fifty-two subjects with irreparable medial or lateral meniscus tissue lesions with intact rim, presence of both horns and stable, well aligned knees, were treated with the scaffold. Tissue ingrowth was assessed using dynamic contrast enhanced MRI (DCE-MRI) at 3 months (n=43), and by histological examination of biopsies (n=44) at 12 months relook arthroscopy. Cartilage status on MRI at 1week, 3, 12 and 24 months, and clinical outcomes were assessed from baseline to 24 months using Visual Analogue Scale (VAS), Knee and Osteoarthritis Outcome Score (KOOS), Lysholm and International Knee Documentation Committee (IKDC).
Background
Patellofemoral replacement is an established intervention in selected patients with severe isolated patellofemoral osteoarthritis. FPV (Wright Medical, UK) is a third generation patellofemoral arthroplasty implant and is the second most used after AVON in National Joint Registry for England and Wales. Reports of survivorship and functional of this implant are scarce in literature.
Aim
Evaluation of functional outcome and survivorship following FPV patellofemoral arthroplasty.
Purpose of Study
To identify the degree of morphological change achievable following the Bereiter trochleoplasty and to establish whether these results are comparable with functional outcomes.
Methods
Seventeen consecutive patients (19 knees) with patellar instability secondary to trochlear dysplasia underwent trochleoplasty, of which 12 knees (12 patients) were radiologically evaluated pre- and post surgery using axial CT and MRI imaging. Their mean age at time of surgery was 28.1 years (15 to 44). The mean follow-up was 2.2 years (0.5 to 5). The following four radiological outcomes were used: trochlear depth (TD), transverse patellar shift (TPS), lateral patellar inclination angle (LPIA) and sulcus angle (SA). All knees were assessed post-operatively using MRI. The axial CT images were reformatted which allowed for direct comparison with MRI. Each knee was radiologically evaluated twice by a senior musculoskeletal radiology consultant to increase data accuracy and assess for intra-observer reliability using the intraclass correlation coefficient (ICC). Functional outcomes consisted of the KOOS, Lysholm, Kujala and Tegner scores.
Background
The management of chondral lesions in the knee, especially in young fit patients, remains an area of considerable controversy. Articular cartilage repair or reconstruction techniques may offer these patients alternatives to arthroplasty or realignment osteotomy. The TruFit plug (Smith & Nephew, London, UK) is a synthetic biphasic polymer scaffold that is designed for implantation at the site of a focal chondral defect. It is intended to resorb and allow tissue ingrowth 6-9 months following implantation and may be placed either arthroscopically or via an open approach depending on the site of the lesion.
Methods
11 patients with focal chondral defects in the knee underwent TruFit plug implantation. Postoperative management entailed a period of 6 weeks of restricted weight bearing or restricted knee flexion according to implantation site. Radiological evaluation with MRI or CT arthrogram (or both) was conducted at various time points postoperatively according to clinical indication. Functional scoring with the Oxford knee score (OKS), Tegner activity scale and Lysholm score were completed.
Aims
The primary aim of this study was to determine the long-term survival of OATS (Osteochondral Autograft Transfer System) (Arthrex, Florida, USA) grafting in our centre and evaluate the reasons for failure, the secondary aim was to ascertain if age, gender, BMI, site or size of OATS graft had any influence on outcome.
Methods
Details of patients undergoing an OATS procedure from 1999 to 2008 were collected. Loosening, graft degeneration or subsequent surgery in the form of arthroplasty, revision OATS¯ or any other osteochondral procedure was considered as failure. Oxford knee score and UCLA activity score evaluated outcome.
Introduction
Infection after total joint arthroplasty is a challenging problem. Clinical symptoms, Erythrocyte sedimentation rate, C-reactive protein level, and cultures of synovial fluid obtained by means of percutaneous aspiration are commonly used to rule out the possibility of persistent infection before reimplantation. However, the sensitivity and specificity of the tests are low. Some authors have suggested that frozen-section analysis should always be performed during the reimplantation in order to rule out persistent infection.
Methods
Retrospective review of 126 revision hip and knee arthroplasty procedure performed from 2002 - 2007 in Derriford Hospital, Plymouth NHS truts, UK. Frozen section was performed in 86 procedures out of the 126 procedures reviewed(68.2 %). A positive frozen section with more than 10 PNLs per HPF was compared with intra operative cultures results. The preoperative CRP results were recorded as well.
Introduction
Peri-prosthetic infections due to P. acnes may present as Prosthesis dysfunction without any obvious sepsis. We present our experience of efficient management of total knee prosthesis infection secondary to P. acnes which is one of the biggest case series.
Materials and methods
From 2008 to 2009, 9 patients diagnosed with P. acnes infection after knee arthroplasty were retrospectively reviewed and analysed for clinical diagnosis; laboratory data (ESR, CRP); Radiological Imaging; number of days for culture growth of P acnes; organism sensitivities; antibiotic regimen and length of treatment and surgical management. Infection was diagnosed by 2 positive cultures.
Aim
To determine the effect of the use of radial extracorporeal shockwave therapy (rESWT) in the treatment of patellar tendinopathy.
Methods
Between 2005 and 2010, twenty eight patients (34 knees), who showed poor or no result from conservative management, had rESWT for patellar tendinopathy. The device used is Swiss Dolorclast¯(EMS, Switzerland). All patients received three weekly sessions of 2000 impulses at 3.0 bar (energy flux density = 0.14 mJ/mm2) and a frequency of 15 Hz. We assessed pain, function and activity and quality of life of the patient before and three months after treatment using KOOS (Knee Injury and Osteoarthritis Outcome Score).
This study aimed to answer the following two questions. Firstly, which activities do people waiting for a total knee arthroplasty rate as important? Secondly, does their self-rated performance of these activities improve after surgery?
Methods
The Canadian Occupational Performance Measure (COPM) was originally designed for use by occupational therapists in order to assess the level of occupational performance and the change in self-perception of their performance over time. COPM is now widely being used as a tool for outcome measurement in a variety of studies such as before and after total hip replacement. However, no reports have been published regarding the outcome of TKA.
Fifty five participants underwent a semi-structured interview in which they were asked to list the activities which they felt were most problematic because of their knee osteoarthritis. For the five most important activities they were asked to rate their performance on a scale of 1-10 (1 =unable, 10 = perfectly able). Other outcome measures included the WOMAC, the Knee Society Score (KSS) and the SF36.
Result
All outcome measures showed a significant improvement after surgery (all p<0.001). Average COPM score improved from 3.8 before to 6.4 one year after surgery.
The change in the COPM demonstrated a moderate correlation with SF-36 physical component, a fair correlation with all three WOMAC scores and a fair correlation with the KSS function scores.
The five most reported activities were ascending and descending stairs (93%), walking, (89%) gardening (35%), playing golf (24%) and kneeling.(18%). The subjective performance of the first four activities improved significantly. However, participants reported a decrease in kneeling ability.
Aims
The purpose of our study was three fold; firstly to assess the survival of closing wedge high tibial osteotomies (CWHTO), secondly to assess any clinical factors or radiological alignment which may affect survival and thirdly to assess the change in tibial inclination and patella height.
Methods
Details of 51 patients undergoing CWHTO for varus gonarthrosis between 1999 and 2007 were assessed for age, BMI, gender, range of movement, meniscal integrity and grade of arthritis. Radiological evaluation included pre and post-operative femoro-tibial axis, tibial slope and patella height. Outcome was also evaluated by Oxford knee score and UCLA activity score. Failure was considered as conversion to arthroplasty.
Introduction
The management of young patients with painful medial compartment osteoarthritis remains controversial. Opening wedge medial high-tibial osteotomy using a locking plate has shown good results in selected patients. This cohort of patients has high physical demands and previous studies have warned against operating on patients with increased body mass index (BMI).
Patients and Methods
Thirty-five patients undergoing valgus high tibial osteotomy between Oct 2004 and Feb 2010. Surgical outcome was assessed using Oxford Knee score, pre- and post-operative pain scores, change in employment and patient satisfaction.
Background
Dual compartment knee replacement has been introduced to allow sparing of the cruciate ligaments and lateral compartment and preserve some biomechanics of knee function.
Aim
To study the early clinical and radiographic results of this new prosthesis.
Background
Unicompartmental knee arthroplasty provides a good alternative to total knee arthroplasty in patients with isolated medial compartment osteoarthritis. There has been variable reporting in the literature as to whether age and sex affect the survival of unicompartmental knee arthroplasty.
Study aims
The aims of this study were to determine whether age and sex were predictors of failure for the Oxford unicompartmental knee arthroplasty.
Purpose
The aim of this study was to compare the short-term and mid-term outcome of lateral UKRs using a single prosthesis, the AMC Uniglide knee implant.
Methods
Between 2003 and 2010, seventy lateral unicompartmental knee replacements (mean patient age 63.6±12.7 years) were performed at our unit for isolated lateral compartmental disease. Range of knee motion and functional outcome measures including the American Knee Society (AKSS), Oxford (OKS) and WOMAC scores were recorded from 19 knees at five years' post-operatively and compared to 35 knees at two-years and 53 knees at one-year post-op.
The conventional Knee arthroplasty jigs, while being usually accurate, often result in prostheses being inserted in an undesired alignment resulting in poor postoperative outcome. This is especially true about unicompartmental knee replacement. Computer navigation and roboticaly assisted unicompartmental knee replacement were introduced in order to improve surgical accuracy of the femoral and tibial bone cuts.
The aim of this study was to assess accuracy and reliability of robotic assisted, unicondylar knee surgery (Makoplasty) in producing reported bony alignment. Two hundred and twenty consecutive patients who underwent medial robotic assisted unicondylar knee surgery (Makoplasty) performed by two surgeons (RJ & GP) were retrospectively identified and included in the study. Femoral and tibial sagittal and coronal alignments and posterior slope of the tibial component were measured in the post-operative radiographs. These measurements were compared with the equivalent measurements collected during intra-operative period by the navigation to study the reliability and accuracy of femoral and tibial cuts.
Results
We found an average difference of 2.2 to 3.6 degrees between the intra-operatively planned and post-operative radiological equivalent measurements.
In conclusion
assuming appropriate planning, robotically assisted surgery in unicondylar knee replacement will result in reliably accurate positioning of component and reduce early component failures caused by malpositioning. Mismatch between preplanning and post-op radiography is caused by poor cementing technique of the prosthesis rather than wrong bony cuts.
Purpose
To identify if the age of the patient was related to satisfaction rates 1 year following unicompartmental knee replacement, in a generalist setting in the U.K.
Methods & Results
Unicompartmental knee replacement (UKR) is a treatment option for patients presenting with isolated medial compartmental osteoarthritis. In many cases, such patients are aged 65 years or younger. The Trent Arthroplasty Register was established in 1990 collecting prospective data on knee arthroplasties performed in this region of the U.K. Self completed questionnaires were sent to 1081 patients who had had a unicompartmental knee arthroplasty 1 year post surgery.
Completed questionnaires were received from 648 patients (60% return rate). Of these patients, 80.2% (451) reported being satisfied, 6.6% (37) unsure of their satisfaction and 13.2% (74) dissatisfied. 78% of those in the 55 or under group (n=92) were satisfied relative to 77.6% in 56-65 yr group (n=264), 90.6% for 66-75 yrs (n=202) and 87.6% for 75+ yrs (73).
Increasing age appears to correlate with increased satisfaction rates. Of those who were dissatisfied, severe pain was the primary reason given as a cause for dissatisfaction. In comparison, patients undergoing total knee arthroplasty (TKA), who were sent identical questionnaires, demonstrated no difference in satisfaction rates in each of the different age groups. The overall satisfaction rate in such patients was 90%.
Laboratory experiments and computational models were used to predict bone-implant micromotion and bone strains induced by the cemented and cementless Biomet Oxford medial Unicompartmental Knee Replacement (UKR) tibial implants.
Methods
Ten fresh frozen cadaveric knees were implanted with cementless medial mobile UKRs, the tibias were separated and all the soft tissues were resected. Five strain gauge rosettes were attached to each tibia. Four Linear Transducers were used to measure the superior-inferior and transverse bone-implant micromotions. The cementless UKRs were assessed with 10 cycles of 1kN compressive load at 4 different bearing positions. The bone-constructs were re-assessed following cementation of the equivalent UKR. The cemented bone-implant constructs were also assessed for strain and micromotion under 10000 cycles of 10mm anterior-posterior bearing movement at 2Hz and 1kN load.
The cadaveric specimens were scanned using Computed Tomography, and 3D computer models were developed using Finite Element method to predict strain and micromotion under various daily loads.
Results and Discussion
Results verify computer model predictions and show bone strain pattern differences, with cemented implants distributing the loads more evenly through the bone than cementless implants. Although cementless implants showed micromotions which were greater than computer predictions, the micromotions were as expected significantly greater than those of cemented implants.
The computer models reveal that bone strains approach 70% of their failure limit at the posterior and anterior corners adjoining the sagittal and transverse cuts (less pronounced in cemented implants). The base of the keel also develops high strains which can approach failure depending on the amount the implant press-fit. The contributions of the anterior cruciate and patellar tendon forces exacerbate the strains in these regions. This may explain why fractures emanate from the base of the keel and the sagittal cut.
STUDY PURPOSES
To evaluate the role of “top up” intra-articular local anaesthetic injection in patients who have had UKR.
METHOD AND RESULTS
43 patients scheduled to have a cemented Oxford UKR were prospectively recruited and randomised. All patients had the same initial anaesthetic regime of general anaesthesia, femoral nerve block and intra-operative intra-articular infiltration. All patients had a multi-holed epidural catheter placed intra-articularly prior to wound closure. Patients had the same operative technique, post operative rehabilitation and rescue analgesia.
An independent, blinded observer recorded post-operative pain scores using a visual analogue score every 6 hours and any rescue analgesia. On the morning after surgery, 22 patients, (Group I), received 20 mls of 0.5% bupivicaine through the catheter whilst 21, (Group II), patients had 20 mls of normal saline by the same observer, after which the catheter was removed.
No statistical difference was found in pain scores on the day of operation between the groups. However, patients in Group I had a significantly better pain score initially post top up and at 6 hours (2.4 (0-8) vs 5.7 (2-9), p<0.001). This cohort of patients required less rescue analgesia (p<0.001). In addition, Group I had statistically significant higher patient satisfaction outcome scores after the infiltration, (p<0.001).
This study was designed to evaluate the performance of a new patient specific interpositional knee device. Treatment of osteoarthritis is evolving, allowing surgical treatment options at an earlier stage. The interpositional knee device is a recently developed patient specific implant used for the treatment of mild to moderate uni-compartmental osteoarthritis. The benefits over traditional methods of surgical management are: it's less invasive, can be a day procedure and does not limit future options. Young Adults with early uni-compartmental arthritis are suitable. A MRI scan of the patient's knee is reviewed by local and US radiologists to decide if the patient is suitable for the implant. A bespoke implant is produced. Prior to insertion an arthroscopic procedure is undertaken to allow proper positioning of the implant.
We treated 27 patients with the iForma Conformis interpositional knee implant in South Wales at the Princess of Wales Hospital, Bridgend and the Royal Glamorgan Hospital, Llantrisant since November 2007. The pre- and post-operative WOMAC scores were recorded. The average age was 54.7 years, BMI 32; 10 females and 20 males. The average pre-operative WOMAC score was 42.2 improving to 62.9 post-operatively. 35 implants were used. 7 patients experienced post-operative problems. No dislocations were reported. Average follow-up was 12.6 months.
Our early experience suggests patient selection plays a role in the outcome following surgery. It indicates that this device is a viable and safe alternative to a uni-compartmental knee replacement.
Introduction
The Signature system has been hailed as a new way to perform arthroplasty of the knee. It combines the accuracy in restoring mechanical axes of navigation with the convenience and familiarity of classical surgical techniques. With this comes the expectation that they should produce better functional results. In the literature, thus far, there is little data to corroborate this. The aim of this paper is to compare the early functional outcomes of this with the cemented AGC knee replacement system.
Methods
Since April 2010, based on requirement, 25 patients underwent Signature knee replacements during this period for symptomatic degenerative or inflammatory arthritis with varying levels of deformity. Oxford functional scores were taken pre-operatively, at 6 weeks, 3 months and 6 months. These were then matched to an equal number of patients that had undergone an AGC knee replacement by the same surgeon. They were matched by pre-operative functional Oxford scores, age and gender.
OBJECTIVE
To examine the short term patient assessed functional results of the Journey BCS ¯(Smith & Nephew) and Triathlon ¯(Stryker Orthopaedics, Mahwah, NJ) total knee replacements when compared to the Scorpio ¯(Stryker) total knee replacement using a multi-surgeon case control design in a single centre.
METHODS
From September 2006 to August 2008 a total of 135 Journey and 97 Triathlon total knee replacements (TKR) were performed. 105 patients with Journey and 90 patients with Triathlon implants were available for follow-up at a minimum of 1 year, with an average of 2 years. Age and sex matched controls were obtained from our pool of patients who had had Scorpio TKR's. The same surgeons using the same approach operated on patients in both groups. All implants were posterior stabilised and all underwent patella resurfacing. All patients were seen pre-operatively and followed up post operatively in a physiotherapist led joint review clinic to assess range of motion (ROM) as well as function using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Oxford Knee Score (OKS) and the High Activity Arthroplasty Score (HAAS - used post operatively only).
Introduction
There is conflicting evidence about the merits of using mobile bearings at total knee replacement (TKR), partly because most randomised controlled trials (RCTs) have not been adequately powered.
Methods
A pragmatic multicentre RCT involving 116 surgeons in 34 UK centres was begun in 1999. Within a partial factorial design, 539 patients were randomly allocated to mobile or fixed bearings. The primary outcome measure was the Oxford Knee Score (OKS); secondary measures included SF-12, EQ-5D, costs, cost-effectiveness and need for further surgery.
Zirconium total knee replacements theoretically have a low incidence of failure as they are low friction, hard wearing and hypo allergenic; we present the five year survival data.
Data was collected prospectively from 212 patients who underwent
There were 92 male and 120 female patients with a median age of 63 years, range 25 to 87. 188 implants were for osteoarthritis and 24 were for rheumatoid arthritis. Eight patients died and six were lost to follow up, the remaining 198 patients reached a minimum of five year follow-up.
At five years, the mean WOMAC score improved from 56 to 35 and the mean SF12 physical component score improved from 28 to 34. The mean SF12 mental component score remained unchanged at 51.
The five year survival with failure due to implant related reasons was 99.5% (95% CI 97.3 - 100). This was due to one tibial component becoming aseptically loose in the first year.
Reoperations excluded from this analysis were downsizing of the tibial component for stiffness and patella resurfacing. When these were included the five year survival was 98.1% (95% CI 95.1 - 99.3).
Our results demonstrate that the Profix zirconium total knee replacement has a low medium term failure rate comparable to the best implants. Further research is needed to establish if the beneficial properties of zirconium improve long term implant survival.
Purpose of Study
In this review, we present the data of one of the largest non-designer, mid- to long-term follow-ups of the AGC carried out by surgeons of differing grades and sub-specialty.
Summary of methods and Results
We present a total of 1538 AGC knees during a 15 year period, of which 902 were followed up by postal or telephone questionnaire focused on Oxford Knee Scores, Visual analogues of function and pain and survival analyses performed. 85.7% of patients had an Oxford knee score of between 0 and 40, with 71.2% scoring between 0 - 30.
65.6% of patients responded with a Visual Analogue Score (VAS) of 0 or 1 at rest (minimum pain = 0) and 53.9% reporting VA scores of 0 or 1 while walking.
87.5% of patients reported Excellent or good functional reports at final follow up and 90.3% reporting excellent or good pain control compared to per-operative levels.
There is a survivorship of 95.88% at 15years.
This large cohort and multi-surgeon & multi-experience level trial reproduces the excellent results as demonstrated by the designer centre (Ritter et al.) and is better than most others in the literature. Mid to long term outcome shows excellent function and analgesia. Complication rates are low and the necessity for revision remains low.
This study reports the first 10-year clinical and radiological follow-up data for the Sigma PFC. The DuPuy Sigma total knee arthroplasty (TKA) is a modification of the well established Press Fit Condylar (PFC) TKA and is used extensively in the UK and worldwide. It is the most commonly used TKA in England and Wales, where it accounts for 34% of all primary TKA.
A total of 235 consecutive Sigma TKAs were performed in 203 patients between October 1998 and October 1999, in our unit. Patients were seen at a specialist nurse led clinic 7 to 10 days before admission and at 6 months, 18 months, 3 years, 5 years and 7-10 years after surgery. Data was recorded prospectively at each clinic visit. Radiographs were obtained at the 5 year and 8-10 year follow-up appointment.
Of 235 knees 171 (147 patients) were alive at 10 years. Twelve were lost to follow up. Nine knees (3.8%) were revised; five for infection and four underwent change of polyethylene insert. Ten-year survival with and end point of revision for any reason was 95.9%, and with and endpoint of revision for aseptic failure was 98.7%. The mean American Knee Society score was 62 at 8-10 years compared with 31 out of 100 pre-operatively. Of 109 radiographs, 47 knees had radiolucent lines but none showed radiological evidence of loosening.
Our results show that the PFC Sigma knee arthroplasty performs well over the first 10 years post implantation.
Statement of Purpose
The UK and Australian clinical experience of an implantable load absorber was reviewed for knee OA patients who have exhausted conservative care, but are not ideal candidates for HTO or arthroplasty due to age, activity level, obesity, or disinclination.
Methods and Results
The load absorber was implanted in 58 patients, with the longest duration exceeding two years. Patients included younger OA sufferers (31-68 years), and had a mean BMI > 30kg/m2. Early surgical experience and adverse events with the device were recorded and clinical outcomes using validated patient reported outcomes tools were collected at baseline, post-op, 2 and 6 weeks, and 3, 6, 12 and 24 month timepoints.
All patients were successfully implanted with a mean surgical time of 76.4 minutes (range 54-153). After a mean hospital stay of 1.7 days (range 1-3), patients resumed full weight bearing within 1-2 weeks and achieved normal range of motion by 6 weeks. Mean WOMAC pain (0-100 scale) improved from 42.4 to 16.1 (p<0.001); mean WOMAC function (0-100 scale) improved from 42.0 to 14.7 (p<0.001). Most patients reported “no or mild” pain (85%) or “no or mild” functional impairment (90%) at last follow-up (9.5 ± 3.5 months). Patients reported high satisfaction with the implant. Initial UK results mirror the positive Australian experience: reduced pain, improved function, and high satisfaction.
Complications arising in the early surgical experience were effectively resolved through revised surgical technique and minor design modifications.
Introduction
Kneeling ability is better in unicompartmental than total knee arthroplasty. There is also an impression that mobile bearing knees achieve better functional outcome than their fixed bearing cousins in unicompartmental and to a lesser extent total joint arthroplasty. In the UK, the market leading unicompartmental replacement is mobile bearing.
Aim
To analyse kneeling ability after total and unicompartmental knee replacement using mobile and fixed bearing inserts.
Purpose
The Oxford Knee Score (OKS) is a validated and widely used PROM that has been successfully used in assessing the outcome of knee arthroplasty (KA). It has been adopted as the nationally agreed outcome measure for this procedure and is now routinely collected. Increasingly, it is being used on an individual patient basis as a pre-operative measure of osteoarthritis and the need for joint replacement, despite not being validated for this use. The aim of this paper is to present evidence that challenges this new role for the OKS.
Method
We have analysed pre-operative and post-operative OKS data from 3 large cohorts all undergoing KA, totalling over 3000 patients. In addition we have correlated the OKS to patient satisfaction scores. We have validated our findings using data published from the UK NJR.
Recent advancements in optical navigated TKA have shown improved overall limb alignment, implant placement and reduced outliers compared to conventional TKA. This study represents the first RCT comparing EM navigation and conventional TKA. 3D alignment was analysed from CT scans. Clinical scores (Oxford Knee Score (OKS) and American Knee Society Score (AKSS)) were recorded at pre-op, 3 and 12 months post-op. Data presented includes 180 patients (n=90 per group) at 3 months and 140 (n=70 per group) at 12 months.
The groups had similar mean mechanical axis alignments (EM 0.31° valgus; conventional 0.15° valgus). Mechanical axis alignment however was improved in the EM group with 92% within +/−3° of neutral compared to 84% of the conventional group (p=0.90). The EM group showed improved coronal and sagittal femoral alignment and improved coronal, sagittal and rotational tibial alignment, which was significant for sagittal femoral alignment (p=0.04). The OKS and AKSS scores were significantly better for the EM group at 3 months post-op (OKS p=0.02, AKSS p=0.04), but there was no difference between groups at 12 months. The mean pre-op range of motion (ROM) for both groups was 105°. This decreased at 3 months to 102° in the EM group and 99° in the conventional group, but there was a significant improvement by 12 months: EM=113° (p=0.012) and conventional=112° (p=0.026). ROM was statistically similar between groups at all assessment phases.
Knee alignment was better restored following EM navigated TKA relative to conventional TKA, but the difference was not significant. The EM group showed greater clinical improvements at early follow-up; however this difference was not sustained at 12 months. ROM was seen to decrease at 3 months but then significantly improve by 12 month post-op. Proving cost-effectiveness for navigation systems in TKA remains a challenge.
The aim of this study was to compare the efficacy of a hyaluronic acid (HA) supplement and a local anaesthetic (Bupivacaine) at providing early and short-term post-operative anagesic control following knee arthroscopy.
Patients were randomised to receive either 10mls of 0.5% Bupivacaine or 10mls of HA into the joint immediately after completion of surgery. WOMAC and Tegner-Lysholm scores were obtained at baseline then at 1, 2, and 6-weeks post surgery. VAS pain scores were obtained at baseline; 1 and 24-hours; and 1, 2 and 6 weeks following surgery.
49 patients received intra-articular Bupivacaine and 49 HA. There was no statistical difference in any of the outcome measures (WOMAC, Tegner-Lysholm, VAS pain scores) at any time point between the groups overall. Patients with grade III-IV chondral defects that received HA reported significantly lower VAS pain scores at rest and movement at all time points.
Use of Bupivacaine and HA intra-articular injection results in equivalent analgesic control in the immediate post-operative period and first six-weeks following surgery when administered immediately at the end of knee arthroscopy. Utilizing HA following knee arthroscopy does not sacrifice analgesic control and minimises exposure to chondrotoxic agents. Selective use of HA may improve pain-control in those with advanced chondral defects.
The aim of this study was to describe the epidemiology of elite youth soccer knee injuries from prospective data collected from forty-one English FA Football Academies over a 5 year period. 12306 players were registered from U9 to the U16 age category.
We studied the incidence of injuries around the knee with particular emphasis upon those causing greater than 28 days time off sport.
There were 609 knee injuries with a mean incidence of 0.71 knee injuries per player per year and a median of 17 training days and 2 matches missed per knee injury. Increased injury rates were seen in older players, in competitive situations and in the latter stages of each half of play. Peaks in injury numbers were seen in early season and subsequent to the winter break. Sprain was the most common diagnosis with the Medial Collateral ligament affected in 23.2% of cases. 609 injuries met the UEFA Model criteria for major injury. In total 60,091 training days and 5,272 match appearances were lost through knee injury.
Knee injuries are common in elite level youth footballers and are often severe in nature, resulting in large amounts of training time lost to injury. Diagnosis of ligament sprain is common leading to prolonged time off, and may mask more serious pathology or inappropriate management.
Introduction
The National Institute for Health and Clinical Effectiveness recommends both low molecular weight heparin (LMWH) and Rivaroxaban for venous thromboembolic (VTE) prophylaxis following lower limb arthroplasty. Despite evidence in the literature that suggests Rivaroxaban reduces VTE events, there are emerging concerns from the orthopaedic community regarding an increase in wound complications following its use.
Methods
Through the orthopaedic clinical directors forum, Trusts replacing LMWH with Rivaroxaban for lower limb arthroplasty thromboprophylaxis during 2009 were identified. Prospectively collected Hospital episode statistics (HES) data was then analysed for these units so as to determine rates of 90-day symptomatic deep venous thrombosis (DVT), pulmonary thromboembolism (PTE), major bleed (cerebrovascular accident or gastrointestinal haemorrhage), all-cause mortality, and 30-day wound infection and readmission rates before and after the change to Rivaroxaban. 2752 patients prescribed Rivaroxaban following TKR or THR were compared to 10358 patients prescribed LMWH. Data was analysed using odds ratios (OR).
Objective
Assess patient compliance with self-administration of subcutaneous low-molecular-weight-heparin (enoxaparin) injections for 14 days following knee replacement surgery.
Methods
Consecutive patients undergoing knee replacement surgery during a 4-month period were identified from a database. All patients had been taught to self administer enoxaparin injections during their in patient stay and asked to self administer the remaining injections after discharge if feasible. Patients were then sent questionnaires designed to assess compliance.
NICE guidelines state patients undergoing elective TKR receive post-operative chemical prophylaxis unless contraindicated, following guideline implementation our aim was to determine VTE incidence and wound complication outcomes related to administration of Rivaroxaban or Enoxaparin.
From April to October 2010 we prospectively studied 294 patients having primary or revision TKR. Each received either Rivaroxoban (n=219), Enoxaparin (n=68), UHF 5000 units (n=4) or no thromboprohylaxis (n=3) post-operatively. Primary outcome was identification of symptomatic post-operative VTE incidence and compared incidence over the same period in 2009 when aspirin was the standard chemical prophylaxis for VTE. Secondary outcomes were prolonged wound oozing rates and wound washout.
VTE occurred in 3 of 219 patients (2 PE, 1 DVT) receiving Rivaroxaban, and 1 PE in a patient who did not receive any thromboprophylaxis. No patients prescribed Enoxaparin developed VTE. In the same period 2009 there were 21 confirmed PEs in 512 patients undergoing TKR. This was statistically significant (Chi squared test p=0.02).
Prolonged oozing was noted in 3 patients receiving Enoxaparin, and 17 patients receiving Rivaroxaban. 6 patients treated with Rivaroxaban returned to theatre, 3 for continuous ooze, 2 for wound dehiscence and 1 for infection. During the same period in 2009, there was only 1 return to theatre for haematoma washout. (Chi squared test; p=0.02).
Following the NICE guidelines, there is a reduction in the PE rate following TKR but there is an increase in the overall return to theatre rate.
Deep vein thrombosis remains a significant and common complication following joint replacement and debate exists over which contributing factors are important. This study investigates the effect of a number of variables on the incidence of symptomatic deep vein thrombosis in knee arthroplasty surgery. Data was collected prospectively on 3449 knee replacements including procedure type, tourniquet time, surgeon, patient age, and gender. These variables were assessed by the use of generalised linear modelling against the presence or absence of symptomatic deep vein thrombosis demonstrated on duplex ultrasonography. The overall deep vein thrombosis rate was 1.6%. The only variable which had an association with confirmed symptomatic DVT was operation type with total knee replacements having a higher incidence than unicompartmental knee replacements (2.2% vs 0.3% p=0.0003). Tourniquet time did not exhibit a statistically significant effect (p=0.63) These data show that the DVT rate in unicompartmental knee replacement is statistically significantly lower than that of total knee replacement. They do not support the notion that increased tourniquet time is associated with an increased risk of DVT.
Purpose of the study
To determine the effectiveness, complications and side effects of Rivaroxaban when used for extended thromboprophylaxis in patients undergoing primary and revision knee arthroplasty.
Methods
Venous Thromboembolism (VTE) prophylaxis following knee arthroplasty remains controversial. As an Orthopaedic Unit, in July 2009 we developed guidelines to help ensure that our patient management was fully compliant with National Institute for Health and Clinical Excellence (NICE) guidelines regarding risk assessment and extended oral prophylaxis following primary and revision knee arthroplasty. We opted to trial the oral anticoagulant drug Rivaroxaban for an initial period of 12 months. All patients undergoing primary or revision knee arthroplasty between 1st July 2009 and 30th June 2010 and who had no contraindications to the prescription of Rivaroxaban were included in a prospective audit aimed at determining compliance with the newly developed unit guidelines as well as the effectiveness and possible side effects/complications associated with the drug therapy. All patients were monitored for a period of 90 days post operatively.
Aim
To evaluate safety and efficacy of performing a total knee arthroplasty (TKA) on patients receiving continuous Warfarin therapy
Methods
We identified 24 consecutive patients receiving long term warfarin therapy who underwent total knee arthroplasty between 2006 and 2008. As a control, we collected the same data from a group of age and sex matched patients not on warfarin. Primary observations were changes in haemoglobin, transfusion rates and complications. Secondary observations were fluctuations in the INR and post operative range of motion (ROM). All procedures were performed by the senior author in a single centre using the same TKA technique.
INTRODUCTION
Tranexamic Acid (TA) has been shown to decrease peri-operative bleeding in primary Total Knee Replacement (TKR) surgery. There are still concerns with regards to the increased risk of thromboembolic events with the use of TA. The aim of this study was to assess whether the use of pre-operative TA increased the incidence of Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) in TKR.
METHODS
Patients who underwent primary TKR between August 2007 and August 2009 were identified from the databases of three surgeons within the lower limb arthroplasty unit. A retrospective case notes analysis was performed. DVT was diagnosed on Duplex Ultrasound Scan and PE on CT Pulmonary Angiogram. A positive result was a diagnosis of DVT or PE within 3 months of surgery.
Background
A number of studies have reported on the early failure of the Oxford unicompartmental knee arthroplasty. However, less evidence is available regarding the outcome following revision of failed unicompartmental knee prostheses to total knee arthroplasty.
Study aims
The study aims were to determine the time to failure and mode of failure for the Oxford unicompartmental knee arthroplasty and to assess the short-term outcome following revision surgery.
Introduction
Revision knee arthroplasty is an increasingly common procedure and can be challenging in the presence of bone defects, ligament instability and soft-tissue deficiencies. Current treatment options in addressing tibial and femoral bone loss in the revision setting include cement, morselised or structural allograft, metal wedges and augments and custom or hinge prosthesis. The aim of this study is to describe our early experience using unique femoral and tibial metaphyseal sleeves as an alternate for dealing with significant tibial and femoral bone loss.
Methods
Porous stepped metaphyseal sleeves were implanted during twenty revision total knee replacements in eleven men and nine women who had an average age of 73.3 years at the time of the procedure. The indications included aseptic loosening in nineteen cases and second stage reimplantation in one case. Bone defects in tibia and femur were classified intra operatively according to AORI classification. All patients were prospectively followed clinically and radiographically for a mean follow up of sixteen months (range 12-26 months).
Purpose of the study
This study was undertaken to evaluate the early results of a new implant system - the metaphyseal sleeve - in revision total knee replacement. The femoral and tibial metaphyseal sleeves are a modular option designed to deal with metaphyseal bone loss and achieve cementless fixation over a relatively wide area in the metaphysis.
Methods
Over three years, femoral and/or tibial metaphyseal sleeves were implanted in 104 knees in 103 patients (54 male and 49 female). The clinical notes and radiographs of these patients were reviewed retrospectively. Thirty one patients had revision for infection, 42 for aseptic loosening, and 31 for instability, pain or stiffness. Eighty nine knees were revised as a single stage and 15 were done as two stage procedure. Minimum follow up is 12 months (average 18.5 months).
Introduction
We wished to quantify the influence of constraint and various principal indications upon functional outcome following aseptic first time revision knee arthroplasty.
Methods
In this single centre, prospective study we have looked into the outcome of 175 total revision knee replacement performed between 2003 and 2008 at a minimum follow-up of 1 year. Data was refined to allow for examination exclusively of those cases where the level of constraint was increased from cruciate retaining or cruciate sacrificing knee replacement to either non linked constrained implant (condylar constrained) or linked constrained (rotating hinge) prosthesis.
Deep joint infection is one of the most dreaded complications of total joint arthroplasty, and urinary tract infections (UTI) are generally believed to be a source for haematogenous seeding of the prosthetic joint. Although patients are often screened for UTI there appears to be minimal evidence on the management of asymptomatic bacteriuria, or for those patients who perform intermittent self-catheterisation prior to joint arthroplasty. This study aims to address this.
We performed an online and postal survey of the British Association for the Surgery of the Knee membership to provide a consensus from a body of professionals. Of the respondents 75% performed 50 or more joint arthroplasty surgery over a 12 month period. For all surgeons, 71.4% provided antibiotic cover for the insertion and withdrawal of urinary catheters. However, only 19% were aware of National guidelines, compared to 76.2% for local guidelines which were more likely to be followed. Two thirds of surgeons would treat asymptomatic bacteriuria prior to surgery, yet 70% of these surgeons were unable to cite evidence for this decision. Similarly, the management of patients requiring intermittent self-catherisation produced a heterogenous response.
Our study suggests there is a lack of consensus and/or awareness amongst specialist knee surgeons for the management of asymptomatic urinary bacteriuria in patients prior to knee surgery. We believe a minimum standard of care be defined by the society to protect both patient and surgeon.
Introduction
In complex primary and revision total knee replacement (TKR) the operating surgeon may encounter proximal tibial bone defects. The correct management of such defects is fundamental to both the initial stability and long-term survival of the prosthesis. Block or wedge-shaped metal augments are used to address some such type II unconstrained defects.
Aim
The aim of this finite element (FE) study was to assess the effects of block and wedge-shaped metal augments upon the shear stresses in the cement mantle at the bone-implant interface of an augmented TKR.
Purpose
This study investigates the effect of early tourniquet release on range of flexion following total knee replacement, and the influence of anticoagulation with Rivaroxaban and Clexane (Enoxaparin).
Method
78 patients were included in the study, who underwent unilateral primary total knee replacement (TKR) in our department under the care of two specialist knee surgeons over a 12 month period. 27 patients underwent TKR with early release of the tourniquet and haemostasis, prior to closure of quadriceps layer: 22 were anticoagulated with Rivaroxaban (GROUP ER), 15 with the low molecular weight heparin Clexane (GROUP EC). Over the same time period, 41 patients TKR with late release of the tourniquet, following closure and bandaging: 13 were anticoagulated with Rivaroxaban (GROUP LR), 28 with Clexane (GROUP LC). A standardised operative technique was employed, and all patients received an AGC (Biomet) PCL-retaining prostheses. Outcome was assessed with range of flexion at 12 weeks postoperatively.
The purpose of this study was to determine the accuracy of MRI scan for the detection of meniscal pathology in our unit. There are published data which show that both sensitivity and specificity can approach 90% when compared to arthroscopic findings.
We retrospectively analysed a single surgeon series of 240 scopes for all indications The arthroscopic reports included an outline diagram of the meniscus upon which the surgeon recorded operative findings. 112 of these patients had also had recent MRI.
We looked at whether the MRI report showed a tear, and this was graded Y/N. The arthroscopic report was graded for tear: Y/N. 66 patients had a positive scan. 64 of these were found to have a tear at surgery. 37 scans were reported as “no tear”, of which 4 were found to have a tear at surgery. Nine scans were not easy to classify as they were descriptive.
In our series of 112 knees, MRI was 90.5% sensitive, 89.5% specific and 90.1% accurate.
When a definite diagnosis of “tear”, or “no tear” was made at scan, there were two false positives and four false negatives. False positives may be unnecessarily exposed to the risks of surgery. Patients with negative scans had a mean delay to surgery of 33 weeks compared to 18 weeks for patients with positive scans. False negatives may wait longer for their surgery. Two of the false negative scans clearly showed meniscus tears which were missed by the reporting radiographer. In our series the scan itself was more accurate than the reporting. It is important to have an experienced musculoskeletal radiologist to minimise the number of missed tears. It is also important for surgeon to check the scan as well as the report.
PURPOSE OF STUDY
We investigated the effect of weekend knee arthroplasty surgery on length of inpatient stay.
METHODS
341 consecutive patients undergoing primary total knee replacement were retrospectively identified. Of these 62 underwent surgery during the weekend. Length of inpatient stay, age, sex, pre-operative haemoglobin, ASA rating, and day of surgery were recorded. Multiple regression analysis was used to determine the effect of these preoperative factors on length of post-operative inpatient stay.
Aim
We aim to compare post-operative length of stay and cardiopulmonary morbidity in patients randomised to either navigated or conventional total knee arthroplasty (TKA).
Method
Patients undergoing primary TKA for osteoarthritis were prospectively assigned randomly to either navigation-guided or control groups and blinded to this.
All patients received a PFC implant (DePuy, Warsaw, IN). In the control group the standard femoral intramedullary and tibial extramedullary alignment rod was used. In the navigation group, the BrainLab (Munich, Germany) navigation system was used. All operations were carried out by one of two consultant orthopaedic knee surgeons.
Length of post operative hospital stay and the development of cardiopulmonary complication were recorded and groups compared.
Purpose
The purpose was to determine if the use of cold irrigation fluid in routine knee arthroscopy leads to a reduction in post operative pain.
Background
Some surgeons use cooled irrigation fluid in knee arthroscopy in the hope that it may lead to a reduction in post operative pain and swelling. There is currently no evidence for this, although there is some evidence to support the use of cold therapy post operatively in knee surgery.
Purpose of the Study
This study aims at investigating the effect of application time of bone cement on the cement-bone interface strength in two types of commercially available bone cements, Cement-A and Cement-B.
Materials and methods
Cement-A and Cement-B were applied to cancellous bone specimens at two different times; 2 and 4 minutes (min). The bone specimens were formulated from bovine bone. Specimens were loaded to failure and the force at which the cement-bone interface failed was recorded. The shear strength of the cement-bone interface was calculated by dividing the force at failure by the cross-sectional surface area of the cement-bone interface.
Purpose
We conducted a prospective study to investigate the role of the LARS ligament system to reconstruct the posterior cruciate ligament and the postero-lateral corner of the knee.
We present a prospective single surgeon case series to evaluate early clinical and functional outcomes of postero-lateral corner and posterior cruciate ligament reconstruction in the knee using the LARS (ligament Augmentation and Reconstruction System) artificial ligament. 23 patients with multi-ligament knee injuries or isolated PCL injuries were treated with a mean follow up of 8 months (range: 2-37 months). Outcomes were assessed using the modified International Knee Documentation Committee score, and a modified Tegner- Lysholm score. 2 patients had acute reconstructive surgery within 7 days of injury, 5 patients within 3 months (semi-acute) and 16 were chronic cases that were operated on after three months from the date of injury.
The LARS ligament reconstruction achieved a significant improvement between preoperative and postoperative assessment in relation to knee stability, function and patient satisfaction. The sooner the patients were treated the greater the improvements in functional scores were noted. Most patients achieved a full functional range of movement within six months. We had 2 complications, one superficial wound infection and one stiff knee requiring a manipulation. To date we have had no LARS ligament failures.
In the short term the LARS functions well, with high clinical patient satisfaction, no signs of progressive laxity, synovitis or failure. We found no significant difference in functional score post reconstruction between the isolated PCL reconstructions and the multi ligament reconstructions. Our results show no early signs of the problems associated with synthetic grafts used in the past. Such grafts appear to be an attractive alternative to the use of autografts and allografts.
INTRODUCTION
We examined whether the introduction of an oral factor Xa inhibitor, increased total blood loss in patients undergoing primary total knee arthroplasty surgery.
METHODS
Two groups were studied. The intervention group were prescribed a factor Xa inhibitor 6-10 hours post-surgery, and the control group were prescribed low molecular weight heparin (LMWH) 6-10 hours post-surgery. All other factors were kept constant.
Pre- and post-operative haemoglobin levels (post-operative on day 2) were recorded. Any requirement for transfusion was also documented. Actual drop in haemoglobin levels was compared between the two groups.
Purpose
The traditional use of pneumatic tourniquets and reinfusion drains in total knee replacement (TKR) has recently been challenged and the aim of our study was to compare the outcomes of three different blood management techniques in primary TKR.
Methods
We prospectively conducted a study of 87 patients with mean age of 71 (44-91) years old. They were randomised into three groups: Group A: 29 patients without the use of tourniquet and reinfusion drain, Group B: 27 patients without the use of tourniquet and reinfusion drain but application of intraoperative cell salvage system and Group C: 31 patients with the use of tourniquet and reinfusion drain. All groups were well matched and all patients were reassessed at the 2nd postoperative day.
Aims
The aim of our study was to determine the prevalence of total knee arthroplasty in different ethnic groups and compare pre-operative and post-operative function using the Oxford Knee Score (OKS).
Background
King's College Hospital serves one of the most ethnically diverse areas of the UK. The prevalence of TKR differs between different ethnic and demographic groups.
A feasibility study of the use of an MRI based patient specific knee arthroplasty system within the NHS.
Introducing new technologies within a public funded health system can be challenging. We assess the use and potential benefit of customised jigs for knee arthroplasty. Outcomes assessed were safety and accuracy of implantation.
Eight knee replacements using custom jigs were compared to 11 conventionally instrumented replacements matched to surgeon and operative day. Parameters measured include tourniquet time; drain output; hospital stay; adjusted change in haemoglobin; complications; and component position on post-operative long-leg alignment films
None of the parameters observed demonstrated a statistically significant difference from the conventional arthroplasty group. No complications were seen in either group. No significant differences were seen in alignment.
Our early experiences show that this technology appears safe and allows accurate implantation of the prosthesis. There was a trend for decreased stay and blood loss. The health economic benefits of navigational arthroplasty have been demonstrated in other studies and come from the lack of instrumentation of the intramedullary canal. MRI based patient specific instrumentation is considered technically easier and more convenient than intra-operative navigation. A larger study is planned to assess the health economic implications of adopting this new technology.
Purpose
Late stage medial unicompartmental osteoarthritic disease of the knee can be treated by either Total Knee Replacement (TKR) or Unicompartmental Replacement (UKR). As a precursor to the TOPKAT study this work tested the postulate that individual surgeons show high variation in the choice of treatment for individual patients.
Method
Four surgeons representing four different levels of expertise or familiarity with partial knee replacement (UKR design centre knee surgeon, specialist knee surgeon, arthroplasty surgeon and a year six trainee) made a forced choice decision of whether they would perform a TKR or UKR based on the same pre-operative radiographic and clinical data in 140 individual patients. Consistency of decision was also evaluated for each surgeon 3 months later and the effect of additional clinical data was also evaluated. The sample consisted of the 100 patients who had subsequently undergone UKR and 40 who had undergone TKR.
Introduction
Patients with knee osteoarthritis frequently complain that they develop pain in other joints due to over-loading during gait. However, there have been no previous studies examining the effect of knee arthritis on the other weight bearing joints. The aim of this study was to examine the loading of the hips and contra-lateral knee during gait in a cohort of patients pre- and post knee replacement.
Methods
Twenty patients with single joint osteoarthritis awaiting knee replacement and 20 healthy volunteers were recruited. Gait analysis during level gait and at self selected speed was performed using a 12 camera Vicon motion analysis system. The ground reaction force was collected using EMG electrodes attached to the medial and lateral hamstrings and quadriceps bilaterally. Patients were invited to return 12 months post-operatively. Data was analysed using the Vicon plug-in-gait model and statistical testing was performed with SPSS v16.0 using ANCOVA to account for gait speed.
Orthopaedic practice is increasingly guided by conclusions drawn from analysis of Joint Registry Data. Analysis of the England and Wales National Joint Registry (NJR) led Sibanda et al to conclude that UKR should be reserved for more elderly patients due to higher revision rates in younger patients. To determine our UKR revision rates at the Great Western Hospital we requested knee arthroplasty data from the NJR, Hospital Episode Statistics (HES) data submitted by our centre to the Primary Care Trust, and interrogated our internal theatre implant database. This revealed significant discrepancies between different data sources.
We collected data from each source for 2005, 2006, and 2007. Operations were classified as TKR, UKR, Other or Unspecified. Results are illustrated in the attached table:
Key findings: Our theatre implant database appears most accurate and includes a greater number of joint replacement operations than NJR or HES data and fewer ‘unspecified’ procedures. On average 15% NJR, 0% HES and 0.3% theatre data procedures were ‘unspecified’. NJR data comprises an average 17 fewer, and HES data an average 36 fewer procedures each year compared with our theatre data. Up to 80% UKRs performed are recorded as TKR in HES data.
In summary there is significant inaccuracy in our NJR data which may affect the validity of conclusions drawn from NJR data analysis. HES data is even less accurate with implications for hospital funding. We strongly advise other centres to continue to maintain accurate implant data and to perform a similar audit to calculate error rates for NJR and HES data. Further analysis is required to identify at which stage of data collection inaccuracies occur so that solutions can be devised. We are currently analysing data from 2008 and 2009.
Rheumatology and Musculoskeletal Sciences, NIHR Biomedical Research Unit, University of Oxford and the Nuffield Orthopaedic Hospital, Oxford
Purpose
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.
Background
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
To critically evaluate exciting new technology to reconstruct menisci for the treatment of post menisectomy pain and relate results to indication and surgical technique in a non-inventor's general knee practice.
Methods
We present our early experience of two non-comparative series with different meniscal implants.
Series 1: Thirteen patients received a Menaflex implant (Regen Bio, USA). Mean age 30, male/female 11/2, mean length of implant 44mm, mean chondral grade 1.9 (Outerbridge). At 24 months clinical scores showed improvement in 12. Second look arthroscopy in 5 however showed disappointing amounts of regenerative tissue. One patient has been revised.
Series 2: Twelve patients received an Actifit implant (Orteq, UK). Mean age 38, male/female 8/4, mean length implant 43 mm, mean chondral grade 1.3. At 12 months all have improved clinical scores. We have performed two second looks, one of these showed excellent integration. However one showed only 50% regeneration. Critical review of the initial implantation shows that there may not have been adequate preparation of the host meniscus tissue.
Introduction
We examined the effect on blood loss of two standardised intravenous bolus doses of 500 mg of Tranexamic Acid, a fibrinolytic inhibitor that reduces blood loss following Knee Arthroplasty (KA).
Materials and Methods
Our study included one hundred consecutive patients undergoing primary cemented KA, who received two standarised bolus doses of 500 mg of Tranexamic Acid. The first dose was administered at induction to anaesthetic and the second dose was administered just before the closure. Data, which included Haemoglobin (Hb), Haematocrit (Hct), Length of Hospital Stay (LOS) and complications, was collected prospectively by an independent observer. Routine blood tests were done on the 1st or 2nd post-operative day.
PURPOSE
The aim of this study was to study the short-term outcome of a contemporary modular revision knee system used in our centre for managing Knee revision arthroplasty
METHODS
Preoperative, one and two years follow up scores and radiographic analysis were recorded from 72 consecutive knee revision cases performed between 2006 and 2008. Outcome measures included the American Knee Society (AKSS), Oxford (OKS) and WOMAC scores and range of motion. The radiographic assessment included review of standing AP, lateral and skyline views. Figgie's method was used to measure the joint line reproduction. A difference of 5 mm (pre=op/post-op) was deemed satisfactory.
Introduction
As intra-operative fluoroscopic identification of the isometric MPFL attachment to the femur can be imprecise and laborious in a surgical setting, we used clinical criteria to identify the isometric point and then studied post-operative radiographs to find out whether it was achieved and compared it with functional outcome.
Materials and Methods
Sixteen patients underwent 17 MPFL reconstructions using autologous semi-tendinosis tendon graft. Clinical judgement was used to identify the optimal point for femoral attachment of the MPFL without fluoroscopy control. Post-operative radiographs at 2 weeks were analysed to confirm whether an isometric point for the reconstructed MPFL was achieved by dividing the distal femur into 4 quadrants by 2 lines on the lateral radiograph. Telephonic interview was conducted to assess functional scores using the Kujala score at a mean follow-up of 13 months.
Statement of purpose
To determine whether the Q-angle, measured in a defined and reproducible manner, correlates with the TT-TG distance in patients with patellar instability.
Methods and results
The Q-angle represents the angle between the vector of action of the quadriceps and patellar tendon. The normal angle is 14+/−3° in males and 17+/−3° in females. An increased Q-angle is associated with an increased risk of patellar instability, although there is disagreement on its reliability and validity. It can be affected by the anatomical points used to record the measurement, the position of the limb and whether the quadriceps are relaxed or contracted. TT-TG is ascertained by axial CT scanning, with a value exceeding 20mm associated with patellar instability.
Q-angles were measured in patients presenting to the patella clinic who had previously undergone Lyon protocol CT scanning for patellar instability. Patients were positioned supine with both feet in neutral rotation taped to a specially designed wooden board (the same position used for CT scanning). The anatomical landmarks were the anterior superior iliac spine, the centre of the patella and the centre of the tibial tuberosity. Both knees were measured with the quadriceps relaxed (relaxed Q-angle) and contracted (contracted Q-angle).
Thirty-four knees were measured, 24 pathological and 10 non-pathological. Pearson moment correlation demonstrated a significant correlation between relaxed Q-angle and TT-TG in all knees (R=-0.377; p=0.028). In pathological knees, contracted Q-angle also demonstrated a significant correlation with TT-TG but to a lesser extent than relaxed Q-angle (R=-0.428; p=0.037, R=-0.578; p=0.003 respectively). Linear regression analysis demonstrated relaxed Q-angle as a significant predictor of TT-TG distance in pathological knees. Contracted Q-angle was not significant.
PURPOSES
Previous studies on patella-femoral morphology have suggested patella maltracking plays an important part in the aetiology but there had been no studies correlating maltracking with articular cartilage change.
METHODS
We studied 147 consecutive patients (294 knees) aged between 10 and 63 presenting with anterior knee pain. All underwent MRI tracking scan of their knees as part of the routine investigations. We analysed the prevalence of maltracking with respect to gender, laterality and age groups, as well as patello-femoral articular cartilage changes.
Purpose
Investigate the functional outcome of medial patellofemoral ligament (MPFL) surgery for patella instability.
Compare functional outcome of direct MPFL repair and reconstruction using hamstring graft.
Methods
All patients that underwent MPFL surgery for patella instability between 2007-2010 were retrospectively identified from operative records. Patients were divided based on whether they underwent direct repair of MPFL, or reconstruction using hamstring graft. The Kujala scoring questionnaire for patellofemoral disorders (max score 100) was used to assess their functional outcome following surgery.
Purpose
Little information is available relating to patient demographics, reasons for failure and types of implants used at time of revision following failure of patellofemoral joint (PFJ) replacement.
Methods and Results
Using data extracted from the NJR a series of 128 PFJ revisions in whom the index primary procedure was also recorded in the NJR were identified. This cohort therefore represents early failures of PFJ replacements revised over a 2 year period which were implanted after April 2003 and included revisions of 11 different brands of PFJ replacement from 6 different manufacturers.
The median age at primary procedure was 59.0 (Range 21.1 to 83.2) of which 43 patients were <55 years old (31 males, 97 females). 19% of the revisions were performed in the first year after implantation, in the second year in 33 cases (26%), in the third year in 39 cases (31%) and between years 4 to 7 in 32 patients (25%).
The commonest reasons for revision were pain (35%), aseptic loosening (18%), subluxation, dislocation or instability (11%), PE wear (7%) and component malalignment (6%). No reason for revision was stated in 30% and only 2 cases were revised for infection. Reason for revision differed according to year of failure but was consistent with respect to age at primary surgery. PFJ revision reason differed from those stated for revisions of primary UKR and TKR from the same period with pain being more prevalent and aseptic loosening and infection being less prevalent in the PFJ group. Single stage revision was performed in 124 cases and 118 underwent cemented revision.
The dysplastic Trochlear is a developmental condition characterised by an abnormally flat or dome-shaped trochlea and it is recognised as a significant cause of patella instability, with the increased sulcus angle being is the most common finding. Surgical correction of the shape of the Trochlear Groove is frequently performed. The described methods in the literature involve open arthrotomy to normalise and maintain the trochlear morphology achieving normal alignment and tracking of the patella.
Open procedures carries a significant risk of arthrofibrosis. The technique was developed in human cadaveric knees at the Donjoy Clinical Education and Research Facility (CERF) in Vista California. We describe an arthroscopic procedure to create a neo-trochlea using gouges, spherical and conical hooded burrs. We studied prospectively a series of 4 consecutive patients with patello-femoral instability secondary to trochlear dysplasia, who were treated by an Arthroscopic trochleoplasty by a single surgeon between 2007 and 2008. Postoperatively the patients were rehabilitated in accordance with our routine Patello-Femoral microfracture Protocol, allowing weight bearing and ROM 0-20 degrees in a long lever brace for 6 weeks. CT scanning at one year showed a complete neo-cortex and cartilage sequenced MRI at 12 months showed complete fill with fibro cartilage.
Pre- and post-operative scores (KOOS, Kujala) were assessed by the patients and a satisfaction questionnaire was completed. The results showed a statistical improvement in the outcome at the 2 year follow up.
Overall, patients (100%) were satisfied with the outcome of their procedure and there have been no adverse events. To our knowledge this technique has not been described before in the English literature and the early results of arthroscopic trochleoplasty are encouraging and offer an alternative to open approaches. Larger numbers and longer follow ups are needed to confirm the long term benefit.
Aim
This study looks for correlation between pre-operative MRI and intra-operative surgical findings regarding the site of medial patellofemoral ligament (MPFL) rupture in first time patella dislocaters with the aim of confirming the reliability of this modality of imaging.
Methods
A retrospective analysis of all patients who were referred for MRI following patella dislocation was performed. The surgical and MRI findings of those who subsequently underwent MPFL repair were compared to look for any correlation.
Aim
To determine the tensile forces across the knee extensor mechanism during walking, in simulated conditions of treatment.
Methods
Gait analysis of six normal subjects was performed, with full weight bearing unilateral immobilisation of the knee during walking. Measurements were taken without then with a brace, unlocked then locked at 0°, 0-10°, 0-20° and 0-30° of flexion. Mean and maximum knee flexion angles were measured, followed by calculation of the mean and maximum forces across the extensor mechanism during loading, supporting and propulsion phases of gait.
Introduction
The role of porosity in the longevity of polymethylmethacrylate (PMMA) bone cement mantles remains unclear, although porosity reduction is probably desirable. It is not known whether pore patterns, pore distribution or pore morphology contribute to failure, since it is difficult to assess these features with traditional techniques. We used a novel microtomographic technique to quantitatively and qualitatively assess porosity in PMMA cements of differing viscosities to establish whether pore distribution can be effectively assessed and to document any differences in porosity (in both quantity, distribution and morphology). Each cement was also examined with and without the addition of vacuum, since this is thought to reduce porosity.
Methods and materials
Four PMMA bone cements of different viscosities (three of the same brand and the fourth chosen due to its popularity) were prepared and moulded according to established protocols (ASTM F451-99a), with and without the addition of vacuum. 25 samples per group (200 total) were prepared and densities for each sample calculated using Archimedes' principle. Four samples per group (total 32) were randomly selected for further analysis. These samples underwent micro-computer tomography (micro-CT) at a magnification of 20× and slice thickness of 13.67μm and reconstructed images were analysed with in-house developed software to measure pore size and volume. Results were analysed and compared with the two-sample T-test assuming significance at P<0.05. Qualitative assessment of pore character and distribution was made using three dimensional (3D) reconstruction.
Hyaline cartilage defects are a significant clinical problem for which a plethora of cartilage repair techniques are used. One such technique is cartilage replacement therapy using autologous chondrocyte or mesenchymal stem cell (MSC) implantation (ACI). Mesenchymal stem cells are increasingly being used for these types of repair technique because they are relatively easy to obtain and can be expanded to generate millions of cells. However, implanted MSCs can terminally differentiate and produce osteogenic tissue which is highly undesirable, also, MSCs generally only produce fibrocartilage which does not make biomechanically resilient repair tissue, an attribute that is crucial in high weight-bearing areas. Tissue-specific adult stem cells would be ideal candidates to fill the void, and as we have shown previously in animal model systems [
At present, research focused on isolating tissue-specific stem cells from articular cartilage has met with modest success. Our results demonstrate that using differential adhesion it is possible to easily isolate articular cartilage progenitor populations from human hyaline cartilage and that these cells can be subsequently expanded
In conclusion, we propose the identification and characterisation of a novel articular cartilage progenitor population, resident in human cartilage, which will greatly benefit future cell-based cartilage repair therapies.
The purpose of this paper was to investigate the predictability of outcome of a consecutive series of cemented unicompartmental or total knee replacements in a single surgeon series.
Between September 2006 and February 2009, ninety-nine cemented, fixed bearing TKR were performed with patellar resurfacing. 52 cemented Miller Galante (Zimmer) Tibio-femoral UKR were performed in the same time interval. The minimum follow up was 6 months. Oxford and AKSS knee scores were collected prospectively at pre-operative and at routine follow up appointments.
Pre-operative mean AKSS Knee score for TKR group was 33.9 and improved to 84.2 at 1 year. Mean scores for Tibiofemoral UKR were 40.4 improving to 84.3 at 1 year.
Pre-operative mean Oxford knee score for TKR group was 34.6 (28%) and improved to 16.6 (65%) at 1 year. Mean scores for UKR were 28.5 (41%) improving to 14.0 (71%) at 1 year. These data would suggest that unicompartmental replacement performs as well as TKR.
However, in the TKR group, 59% achieved a knee score >85 and 23% an Oxford score >80%. In the UKR group, 67% achieved knee score >85 and 45% an Oxford score >80%. Conversely, only 5% of TKR achieved knee score <50 and 20% Oxford score <50% whilst 10% of UKR had a knee score <50 and 26% and Oxford score <50%.
These data show that whilst mean outcomes for TKR and UKR look similar, TKR offers a more predictable outcome with fewer clinical failures but also fewer excellent results. UKR offers a more polarised set of outcomes with far more clinically excellent results but also more clinical failures. These data can inform the ongoing debate regarding the role of unicompartmental arthroplasty. Patient selection is clearly critical but remains an inexact process.
Purpose
The aim of the present study was to look at survivorship and patient satisfaction of a fixed bearing unicompartmental knee arthroplasty with an all-polyethylene tibial component.
Materials and Methods
We report the survivorship of 91 fixed bearing unicompartmental arthroplasties with all-polyethylene tibial components (Preservation DePuy UK), which were used for medial compartment osteoarthritis in 79 patients between 2004 and 2007. The satisfaction level of patients who had not undergone revision of the implant was also recorded. For comparison, we reviewed 49 mobile bearing unicompartmental arthroplasties (Oxford UKA Biomet UK Ltd), which had been used in 44 patients between 1998 and 2007.
The aim of this study is to assess the accuracy of patients' shoe size as a predictor of femoral component size of Oxford unicompartmental knee replacement (UKR).
A retrospective study was conducted to identify the correlation between patients' shoe size (British system) and the femoral component size. After excluding patients who died (n=2) and patients in whom the implanted femoral component size was inaccurate (n=13), the remaining cases (93 UKR in 88 patients) formed the study sample. Postoperative radiographs were reviewed to determine femoral component fit. We found positive correlation between shoe size and femoral component size. In females; a shoe size from 2.5 to 6 predicted a small femoral component and shoe size from 6.5 to 8.0 predicted a medium femoral component. In males, a shoe size from 6 to 9.5 predicted a medium femoral component and a shoe size from 10 to 13 predicted a large femoral component. This relation predicted the femoral component size accurately in 80% of cases. In the rest of cases, the prediction was only one size smaller or larger than the ideal size. A subgroup analysis, after excluding patients who changed their shoe size during adulthood after foot surgery or pathology (n=20), showed an accuracy rate of 81%.
Shoe size is a simple method that predicts femoral component size more accurately than other methods currently used such as templating, tibial component size and height based on gender.
The outcome and survivorship of osteotomy for medial compartment osteoarthritis are closely correlated to the changes in the weight bearing axis. Questions remain over the optimal correction when undertaking medial unicompartmental knee replacement (UKR).
Prospective data was collected on 50 patients (30F:20M) undergoing fixed bearing medial UKR which included pre-operative and 12 month Oxford Knee Scores and pre and post-operative weight-bearing long-leg radiographs.
The weight bearing axis was measured from the centre of the femoral head to the mid-point of the talus. The point at which this axis crossed the tibial plateau was expressed as a percentage of the width of that plateau - 0 (medial cortex) to 100% (lateral cortex).
Regression method and correlation coefficients were used to assess the relationship between the response and variables.
A significant correlation was seen between the 12 month score and the change in axis, which was maintained when the pre-operative score was adjusted for (p = 0.043 and 0.046 respectively). Larger changes in scores were seen with larger changes in axis (p = 0.046) when the pre-operative axis was adjusted for.
Higher BMIs reported worse scores at 12 months (p = 0.022) and a smaller overall change in score one year post-operatively (p = 0.037). This significance was improved when the pre-operative scores were adjusted (p = 0.017 and 0.017 respectively).
Proximity of correction of axis to the assumed contralateral normal was weakly correlated (p = 0.049) to the 12 month score, especially when BMI was corrected for.
These results suggest that the weight bearing axis and BMI do play a significant role in early patient outcomes following fixed bearing unicompartmental knee replacement.
INTRODUCTION
Establishing a full-thickness cartilage in the lateral compartment and functionally intact ACL is vital before proceeding with unicompartmental knee replacement (UKR). The aim of this study is to assess whether MRI is a useful adjunct in predicting suitability for UKR, as compared to standard and stress radiographs.
METHODS
We identified 50 patients with a knee found suitable for UKR based on their standard and stress radiographs (full-thickness cartilage on lateral side). These patients underwent an additional cartilage-specific MRI scan to identify the status of ACL and the lateral compartment. The final decision regarding the suitability for UKR was based on the intra-operative observation.
Aims
Wales in collaboration with the Welsh Assembly Government, has attempted to start a national ligament register.
Introduction
Norway is the lead in Europe for running a successful national quality knee ligament registry. As yet there is no UK wide registry encompassing all forms of knee ligament surgery. The issue has been discussed at previous society meetings, but no consensus has been reached.
Purpose
The purpose of this study was to assess radiologically the absorption of a poly L-lactide bioabsorbable interference screw used in anterior ligament reconstruction.
Methods
A case series of ten sequential patients undergoing anterior ligament reconstruction with a four-strand hamstrings technique were assessed with MRI scans at one, two, four, seven and ten years postoperatively. The scans were reported by an independent radiologist, with respect to resorption of the screw and post resorption changes in the bone. Fixation of the graft in ACL surgery is varied from metal interference screw, resorbable screws made of PLLA, and staple fixation. The advantage of resorbable screws allow imaging of the knee postoperatively, and the perceive benefit of screw resorption and replacement with host bone.
Purpose
To review the Five year survivorship of Kinnemax TKA performed at the NHS Treatment Cantre, Weston-Super-Mare (WSM), and compare it to a similar cohort from our institution.
Introduction
As part of the government's initiative to reduce waiting times for major joint surgery in Wales, the Cardiff and Vale NHS Trust (CAVOC) sent 224 patients (258 knees) to the NHS Treatment Centre in Weston-Super-Mare (WSM) for total knee arthroplasty. Controversy remains as to the unexpectedly high revision rates previously seen.
In this study we evaluate whether a single dose of intravenous Tranexamic acid on wound closure leads to a significant reduction in both blood loss and transfusion rates following primary total knee arthroplasty.
We recruited patients prospectively who were undergoing primary total knee replacement over an 11 month period from 1st January to 12th November 2009. Patients were divided into two groups. Group A were given a single 500mg dose of intravenous Tranexamic acid on wound closure and group B did not receive Tranexamic acid. 282 were eligible for the study, but 59 were excluded. There were 81 patients in group A and 142 patients in group B. The group populations were matched for age, sex, body mass index, ASA (American Society of Anaesthesiologists) grade, and pre-operative haemoglobin. The average post-operative haemoglobin drop was 1.76 g/dl in group A, compared with 2.37 g/dl in group B. The transfusion rate was 1.2% in group A, compared with 12% in group B.
After taking into account the possible confounding factors, post-operative haemoglobin drop (p< 0.001), transfusion rate (p=0.026) and length of hospital stay (p=0.014) were shown to have a significant difference between the two groups (using multiple linear, logistic or ordinal logistic regression). From our results, the use of 500mg of intravenous tranexamic acid during closure of the wound during total knee replacement significantly reduces the post-operative haemoglobin drop, reducing the need for transfusion, and may reduce the length of hospital stay.
Allogeneic blood transfusion is associated with complications and significant cost. The RD&E has looked at the use of autologous drains to decrease the frequency of allogeneic transfusion after our study of 100 cases showed an improved post-operative haemoglobin and reduced length of stay. In 2007 a protocol to identify those patients of increased need for an autologous drain was made using a study of 191 cases showed an average haemoglobin drop post-operatively of 3.05g/dl and average intra-operative blood loss of 285 ml. This protocol gave triggers for autologous drain use; preoperative haemoglobin of <13g/dl, intra-operative blood loss >400ml, tourniquet use, patient weight <50kg and patients refusing donated blood.
In 2007-08, 65% of a further 275 cases analysed met the triggers for use of an autologous system. The remaining patients received low vacuum drains. Of the 275 patients, only 2 (<1%) of those who did not fulfil the criteria for an autologous drain required allogeneic blood, compared with 43 patients (24%) of those deemed high risk of transfusion, and assigned autologous drains. The protocol was successful in identifying those patients who required additional support and expenditure to minimise allogeneic blood transfusion.
Analysis of this data led to recommended changes to the protocol in order to maximise the efficiency of the autologous drain use.
Due to the increased cost of autologous drains (£68) compared with the low vacuum systems (£32), and the cost of allogeneic units at £141, the expenditure per patient was calculated and shown to fall from £92 in 2007 to £78 in a further patient cohort in 2010.
In conclusion, this protocol allows the clinician to appropriately target the use of the more expensive autologous drains to those of increased risk of transfusion. This helps to minimise unnecessary allogeneic transfusion, and this has been shown to be cost effective.
Purpose of the study
Release of tight lateral structures is an integral part of balancing the valgus knee during knee replacement surgery. The posterolateral capsule is released through an inside-out technique. The common peroneal nerve is in close proximity to the capsule during this step. This study was undertaken to determine the distance of the nerve and the safe level for the posterolateral release.
Methods
MR scans of the knee of 100 patients were evaluated. The age range of selected patients was 50 to 70 years. The distance of the nerve was measured to the closest point on the posterolateral capsule. Two separate measurements were taken - one 9mm above the joint line indicating the distal femoral resection level and the other 9mm distal to the joint line indicating the level of tibial resection. A third point was at the joint line level. The position of the nerve was also recorded in relation to the cross section of the femur/tibia on a ‘clock-like’ reference.
Introduction
It is now widely accepted that acute knee dislocations should be managed operatively. Most published studies are from outside the UK and from major trauma or specialist centres. The aim of the study is to report the functional outcomes of all patients presenting with an acute knee dislocation at our institution all of whom were surgically managed. The results were then compared to other published series. The hypothesis being that there would be no significant difference in the functional outcome scores between the groups.
Methods
All patients presenting with an acute knee dislocation over the last 15 years were included in the study. The patients were followed up using functional assessment scores: Knee outcome score (ADL), Knee outcome score (sports), Tegner Lysholm Scores and overall Patient Satisfaction. The patients were classified according to the Schecnk classification of knee dislocations.
Purpose
To highlight the cardiovascular responses of a trainee and supervising consultant while performing Total Knee Arthroplasty (TKA) and to demonstrate the impact that supervision has on both their responses.
Methods
A third year orthopaedic trainee and his consultant underwent non-invasive, continuous cardiac monitoring while performing three primary TKAs. The consultant performed one TKA with the trainee assisting. The trainee then performed two TKAs as primary surgeon. The consultant supervised one TKA scrubbed and the other un-scrubbed.
A third person noted the timing of each distinct intra-operative step. A significant peak was defined as an increase in heart rate (HR) of >10%.
High flexion designs are intended to provide a greater range of knee flexion and possibly improve flexion in stiff knees. This study assessed the effects of two implant designs. A posterior stabilised high flexion mobile bearing (MB) design vs a cruciate retaining standard fixed bearing (FB) design.
The aim of this study was to assess whether implant design has an effect on the functional outcome one year after total knee arthroplasty (TKA).
Methods
Ninety patients with knee osteoarthritis on the waiting list for unilateral TKA were recruited and randomly allocated to either the MB or FB group. Patients were assessed between one and four weeks before, and one year after TKA. Primary outcome was knee flexion during high flexion activities of daily living such as stair ascending and descending and squatting as measured using gait analysis. Knee flexion in long sitting using a manual goniometer and the WOMAC were also recorded. Two sample t-tests were used to investigate statistical differences between the two groups pre- and postoperatively.
Results
Average age was 69 years. Thirty-three received the MB design and 39 the FB design. Age, gender balance and pre-operative flexion (112 and 113 degrees in the FB and MB groups respectively) were the same in both groups. There were no statistically significant differences in post-operative knee flexion during functional activities. Knee flexion in sitting and the stiffness and function components of the WOMAC were also similar between the two groups (p>0.05). However, post-operatively the WOMAC pain component was slightly higher in the MB group (4.2 vs 2.4 points, p<0.05).
Introduction
Traditional TKR designs exhibit abnormal and unpredictable kinematics: with posterior subluxation in extension and anterior slide with flexion. These can contribute to restricted knee flexion and reduced quadriceps efficiency. Newer designs attempt to provide “guided motion” with the aim of mimicking normal knee kinematics. The Journey (Smith & Nephew) BCS TKR incorporates both an anterior and a posterior cam/post mechanism while Triathlon PS TKR (Stryker) incorporates a posterior cam/post mechanism. This study compares the in-vivo kinematics of these two designs and compares it with normal knee.
Methods
Knee kinematics of 10 patients with Journey-BCS TKR and 11 patients with Triathlon PS TKR; all with excellent clinical outcome (average age: 65) were analysed. Patients underwent fluoroscopic assessment of the knee during a step-up and deep knee bend exercise. 2D fluoroscopic images were recorded. Data was analysed for patella tendon angle (PTA) and contact points using a 3D model fitting technique. This data was compared to normal knee kinematics (n=20).
In recent years tribological development of knee replacement impants has beeen introduced with several benefits. However, concomitant problems were noticed following widespread use.
High-flexion total knee replacement (PFC RPF DePuy) has been developed with a view to improve flexion and the design is expected to have a better patello-femoral biomechanics. However, high secondary patella resurfacing rate has been noticed in the current series.
We have retrospectively reviewed 119 knees in 96 patients who underwent RPF knee replacement with selective patellar resurfacing from 2006 to 2010 by the senior author. 71 were performed without primary resurfacing while 48 in knees patella was resurfaced primarily due to significant symptomatic arthritic changes. Majority were females (57 versus 39 males). Average follow-up period was 37 (12-62) months.
Twelve (16.9%) knees were subjected to secondary resurfacing due to continuing anterior knee pain. Average time from primary total knee replacement to secondary resurfacing was 18 months (8-35). Most of the patients were satisfied following the secondary resurfacing.
Mean Oxford Knee Score in the group where the patella was resurfaced primarily was 33.1 (9-48), in the group where the patella was not resurfaced 32.8 (11-47), in the secondary resurfacing group 31.8 (14-43) and in the revision group 20.5 (16-25).
RPF knee replacements in our series have a considerably higher rate of secondary patellar resurfacing as compared with published literature. We recommend primary patellar resurfacing of all RPF knee replacements to avoid this problem. Further analysis of the prosthetic design would be beneficial in relation to clinical outcome.
No of patients-96
Total no of knee-118
Av age-66.5
Females-57
Males-39
Patella not resurfaced- 73
Resurfaced-45
Revised-10(13.7%)
Revision to TKR (TC3) for different reason-3(2.54%)
Average time from primary to secondary resurfacing-
Introduction
This study investigates the effect of Rivaroxaban (Bayer HealthCare) on early post-operative stiffness in primary total knee replacement.
Methods
The anticoagulant of choice for total knee arthroplasty in our Department was changed from Enoxaparin to Rivaroxaban in September 2009. We reviewed a consecutive, multi-surgeon, multi-implant series of primary total knee replacements for a 6 month period prior to (group A) and after (group B) the treatment change. All patients were reviewed by an independent Clinical Specialist Physiotherapist at 6 weeks post-surgery, where the range of movement was recorded prospectively using a goniometer. A stiff knee replacement was defined as one with 15 degrees of extension deficit or flexion to less than 75 degrees at 6 week follow up. All data was analysed on an intention to treat basis.
Aim
The aim of this FE study was to analyse the comparative behaviour of cement and metal based augments in TKR and quantify the stresses within these different augments and underlying cancellous bone.
Materials and methods
A three-dimensional FE model was constructed from a CT scan of the proximal tibia using SIMPLEWARE v3.2 image processing software. The tibial component of a TKR was implanted with either a block or wedge-shaped augment made of either metal or cement. The model was axially loaded with a force of 3600N and testing was conducted with both evenly and eccentrically distributed loads.
Purpose
To review the outcomes of patients undergoing manipulation under anaesthetic (MUA) after primary total knee arthroplasty (TKA) and predict those that may require such a procedure.
Methods
We prospectively analysed all patients who required MUA post TKA performed by 2 surgeons using the same prosthesis from 2003 to 2008 and compared them to a control group of primary TKA matched for age, gender and surgeon. All patients in both groups had pre- and post-operative measurements of range of movement. In addition risk factors were identified including warfarin and statin use, diabetes and body mass index.
Purpose
To examine the clinical characteristics of patients undergoing knee arthroplasty with a pre-operative Oxford Knee Score >34 (‘good’/‘excellent’), and assess the appropriateness of surgical intervention for this group.
Background
In the current cost-constrained health economy, justification of surgical intervention is increasingly sought. As a validated disease-specific outcome measure, the pre-operative Oxford Knee Score (OKS) has been suggested as a possible threshold measurement in knee arthroplasty. However, contrary to expectations, analysis of pre-operative OKS in the joint registry population demonstrates a normal distribution curve with a sub-group of high-scoring patients. This suggests that either the baseline OKS does not accurately define surgical threshold, or that patients with a high OKS are inappropriately having knee replacements.
We set out to demonstrate the 10-year survivorship of the PFC sigma TKA in a young patient group.
Demographic and clinical outcome data were collected prospectively at 6 months, 18 months, 3 years, 5 years and 8-10 years post surgery.
The data were analysed using Kaplan Meier survival statistics with end point being regarded as death or revision for any reason.
203 patients were found to be ≤55 years at the time of surgery. Four patients required revision and four patients died. Another four patients moved away from the region and were excluded from the study.
A total of 224 knees in 199 patients (101 male and 98 females.) 168 patients had a diagnosis of Osteoarthritis and 28 with inflammatory arthritis. Average age 50.6 years range 28-55 years (median 51).
Ten-year survivorship in terms of revision 98.2% at ten years 95% confidence interval.
Our results demonstrate that the PFC Sigma knee has an excellent survival rate in young patients over the first 10 years.
TKR should not be withheld from patients on the basis of age.
The aim of this study was to compare the long-term outcome from total knee replacement (TKR) in young versus old patients in terms of pain and functional outcome.
We used our arthroplasty database which recorded prospectively pain and American Knee Society scores at regular intervals over ten years after TKR. The procedures used a modern, cemented resurfacing type cruciate retaining prosthesis. A cohort of young patients (≤55 years) were identified. A control group of patients > 56 was identified, matching for ASA, body mass index and underlying condition. Change over time was analysed using a factorial repeated measures ANOVA test, which allowed for investigation of difference between groups.
40 Knees in 26 patients were identified. 2 patients died prior to follow up, 2 were revised within the study period. (1 for infection at 2 years and one for change of poly at 7 years) and a further 4 were lost to follow up. 7 knees could not be matched and were excluded. This left a study group of 24 young and 24 older knees.
Pain scores (p=0.025) and American Knee Society “Knee” (p<0.001) and “Function” (p<0.001) scores changed significantly over time. There were however no statistical differences over the 10 year period in pain (p=0.436) and knee performance (0.618) but overall function was higher throughout the period in the younger group (=0.004).
Knee replacement in younger patients produces similar outcomes in terms of pain and function compared with older patients and TKR should not be withheld purely on account of age.
