Revision knee arthroplasty is a complex procedure with the number and cost of knee revision procedures performed per year expected to rise. Few studies have examined adverse events following revision arthroplasty. The objective of this study was to determine rates of serious adverse events in patients undergoing revision knee arthroplasty with consideration of the indication for revision (urgent versus elective indications) and to compare these with primary arthroplasty and re-revision arthroplasty. Patients undergoing primary knee arthroplasty were identified in the UK Hospital Episode Statistics. Subsequent revision and re-revision arthroplasty procedures in the same patients and same knee were identified. The primary outcome was 90-day mortality and a logistic regression model was used to investigate factors associated with 90-day mortality and secondary adverse outcomes including infection (undergoing surgery), pulmonary embolism, myocardial infarction, stroke. Urgent indications for revision arthroplasty were defined as infection or fracture, and all other indications were included in the elective indications cohort. 939,021 primary knee arthroplasty cases were included of which 40,854 underwent subsequent revision arthroplasty, and 9,100 underwent re-revision arthroplasty. Revision surgery for elective indications was associated with a 90-day rate of mortality of 0.44% (135/30,826; 95% CI 0.37-0.52) which was comparable to primary knee arthroplasty (0.46%; 4,292/939,021; 95% CI 0.44-0.47). Revision arthroplasty for infection, however, was associated with a much higher mortality of 2.04% (184/9037; 95% CI 1.75-2.35; odds ratio [OR] 3.54; 95% CI 2.81-4.46), as was revision for periprosthetic fracture at 5.25% (52/991; 95% CI 3.94-6.82; OR 6.23; 95% CI 4.39-8.85). Higher rates of pulmonary embolism, myocardial infarction, and stroke were also observed in the infection and fracture cohort. These findings highlight the burden of complications associated with revision knee arthroplasty. They will inform shared decision-making for patients considering revision knee arthroplasty for elective indications. Patients presenting with infection of a knee arthroplasty or a periprosthetic fracture are at very high risk of adverse events. It is important that acute hospital services and tertiary referral centres caring for these patients are appropriately supported to ensure appropriate urgency and an anticipation for increased care requirements

Abstract. Introduction. In revision knee arthroplasty, rotating hinge implants (RHK) have been considered to result in higher complication rates and lower survivorship when compared to constrained condylar implants (CCK). The aims of this study were to compare patient reported outcome measures (PROMs), complication rates and survivorship of RHK and CCK used in revision arthroplasty at a single, high volume elective orthopaedic centre with previously validated bespoke database. Methodology. One hundred and eight patients who underwent revision knee arthroplasty with either CCK or RHK and matched our inclusion criteria were identified. EQ5D, Health State and Oxford Knee Scores were collected pre-operatively and at 1 year post-operatively. Complication data was collected at 6 weeks, 6 months, 1 year and 2 years post-operatively. NJR data was interrogated, in addition to our own database, to investigate implant survival. Results. There was no statistically significant difference between RHK and CCK in implant survival at two to twelve years of follow up. In addition, we observed no statistically significant difference in the PROMs scores and complication rates of the two implants. Conclusion. This study shows that both the RHK and CCK remain viable options in revision arthroplasty, the implant survival and complication rate were comparable. We recommend prospective randomised control trials with long-term follow up to further investigate the use of CCK and RHK implants in revision knee arthroplasty

Abstract. Multidisciplinary team (MDT) meetings in orthopaedic surgery are evolving. The goals include patient optimisation, surgical planning and discharge arrangements, individually on a patient specific basis. In line with British Association Surgery of the Knee and GIRFT guidelines, we report our regional experience on the implementation and evolution of our regional Revision Knee Arthroplasty MDT. We undertook a retrospective review of the process, cases discussed and quality assurance conducted in the weekly MDT. Since implementation of the MDT meeting in January 2019, 550 patients with painful joint replacements have been discussed. In May 2021, we formalised our ‘terms of reference’ and ‘standard operating procedures’ which are adhered to by the consultants operating within the network, all of whom attend the meeting. A proforma has been developed and is completed for all cases capturing all pertinent information. All cases are graded according to R1, R2, or R3 complexity scale. Since its inception, the MDT has looked at all post-operative imaging, we now describe a new classification system for grading the appearances. Confirmation of the pre-operative plan and actual surgical intervention is reviewed and audited. In addition, confirmation of indication of revision at the time of operation is reviewed and validated for accuracy with benefits to the unit, individual surgeon and the NJR. In conclusion, the implementation of the revision MDT facilitating pre-operative revision arthroplasty discussion and post-operative quality assurance processes enable surgeons to educate, reflect on their practice and ensure that the highest standards of care are being provided

Abstract. Introduction. The objective of this study was to determine rates of serious adverse events in patients undergoing revision knee arthroplasty with consideration of the indication for revision and compare these with primary knee arthroplasty. Methodology. Primary and revision arthroplasty procedures were identified in the national Hospital Episode Statistics and were linked by patient and side. A logistic regression model was used to investigate factors associated with 90-day mortality (primary outcome) and secondary serious adverse outcomes. Urgent indications for revision arthroplasty were defined as infection or fracture; other indications (e.g. loosening, instability, wear) were included in the elective cohort. Results. 939,021 primary knee arthroplasty and 40,584 revision cases were included. Revision surgery for elective indications was associated with a 90-day rate of mortality of 0.44% (95% CI 0.37-0.52) which was comparable to primary knee arthroplasty (0.46%; 95% CI 0.44-0.47). Revision arthroplasty for infection, however, was associated with a much higher mortality of 2.04% (95% CI 1.75-2.35; odds ratio [OR] 3.54; 95% CI 2.81-4.46), as was revision for periprosthetic fracture at 5.25% (95% CI 3.94-6.82; OR 6.23; 95% CI 4.39-8.85). Higher rates of PE, MI, and stroke were observed in the infection and fracture cohort. Conclusion. Patients presenting with infection of a knee arthroplasty or a periprosthetic fracture are at very high risk of adverse events. It is important that acute hospital services and tertiary referral centres caring for these patients are appropriately supported to ensure appropriate urgency with an anticipation for increased care requirements

Abstract. Introduction. Anxiety and depression are risk factors for poor outcome following knee replacement surgery. The aim of this study was to investigate the prevalence of anxiety and depression before and after primary (pKR) and revision knee replacement (rKR). Methodology. Retrospective cohort study. 315,720 pKR and 12,727 rKR recruited from the NHS Patient Reported Outcome Measures (PROMs) programme from 2013–2021. Anxiety and depression were defined using: (i) Survey question: “Have you been told by a doctor that you have depression? Yes/No”; (ii) EQ-5D anxiety/depression domain. Rates of EQ-5D anxiety/depression were investigated at baseline and at 6-months following surgery. The prevalence of depression was investigated by patient age and gender. Results. Overall, 28,434/315,720 (9.0%) pKR and 1,536/12,727 (12.0%) rKR reported pre-operative depression. For all age groups, depression was more common in female than male patients. Prevalence of depression reduced with age (<60 years: 16.8% pKR, 22.7% rKR; 80+ years: 5.3% pKR, 5.2% rKR). Depression was most prevalent in female patients, under 60 years undergoing rKR (25.6%). Pre-operation, 109,000/303,998 (35.9%) pKR and 5,433/12,216 rKR (44.5%) reported moderate or extreme EQ-5D anxiety/depression. Post-operation, 65,351/308,914 (21.2%) pKR and 4,176/12,409 rKR (33.7%) reported moderate or extreme EQ-5D anxiety/depression. Conclusion. Anxiety and depression were prevalent in patients undergoing knee replacement surgery. Patients undergoing revision procedures, female patients and younger patients had the highest rates of depression. Large improvements in anxiety/depression were observed at early follow-up after pKR and rKR

We identified 26 tibial tubercle osteotomies (TTOs) performed in 23 revision knee arthroplasties between 2009 and 2013. Average age at last operation was 66 (33–92). Mean follow-up period was 14 months (3–33). Eleven TTOs were performed in 10 knees for single stage revisions and 15 TTOs were performed in 13 knees for 2 stage revisions in the setting of deep infection. In this infected subset 11 patients had a TTO performed at the first stage. This osteotomy was left unfixed to avoid leaving metalwork in a potentially contaminated wound, reopened, and then definitively secured with screws at the second stage. Our technique involves fashioning a long 7×1cm tibial tuberosity osteotomy without a proximal step-cut. All osteotomies united with no fractures. Minor proximal migration was noted in one case associated with screw loosening. There was no proximal migration noted in the 2 stage cases where the osteotomy had been left initially unfixed. There were no extensor lags. We conclude that TTO is a safe and reproducible procedure when adequate exposure cannot be obtained in revision knee arthroplasty. In 2 stage revisions sequential osteotomies does not decrease union rates and leaving the osteotomy unfixed after the first stage does not cause any issues

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 1. st. July 2009 and 30. th. 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. Results. A total of 415 patients were included in the audit (336 primary knee arthroplasty, 27 revision knee arthroplasty, 6 patello-femoral resurfacing, 46 medial unicompartmental knee arthroplasty). Of this group eight had a confirmed VTE (six deep vein thrombosis, two pulmonary embolism). A further 29 patients had post-operative complications which may be attributed in part to the action of Rivaroxaban. The drug was discontinued prematurely for 22 patients. Conclusions. Our results indicate that Rivaroxaban is effective in providing extended VTE prophylaxis to patients undergoing knee arthroplasty surgery. However, as anticipated, anticoagulation therapy does cause associated wound problems

Purpose: To examine the outcome of primary and revision knee arthroplasty in very elderly patients. Methods and Results: Patients in their 90th year of life who underwent primary or revision knee arthroplasty between January 2000 and September 2007 were identified. Data was collected regarding demographics, ASA grade, co-morbid factors, complications, length of inpatient stay, the need for transfusion and discharge destination. Thirty day, 1 year and current mortality figures were calculated. Twenty one procedures were performed on 18 patients with a mean follow up of 18.8 months (3–57.9). There were 14 primary total knee replacements and 7 revision procedures. The mean age at the time of surgery was 90 years and 10 months (89 years 1 month to 94 years 4 months). The majority of patients were female (15). All patients were ASA grade 2 or 3. The average orthopaedic inpatient stay was 17 days. Thirty percent of patients required a period of further inpatient rehabilitation or convalescence after discharge from our institution. Nine patients experienced a post-operative complication. Mortality at 30 days was 0%, at 1 year 6% (1/16), and is currently 17% (3/18). Conclusion: Very elderly patients are able to tolerate primary and revision knee arthroplasty although there is a high rate of peri-operative complications. We propose that there should be a different tariff for arthroplasty procedures in extremely elderly patients to reflect the increased rate of complications and prolonged postoperative hospital stay

Purpose. Although classic teaching holds that the least amount of constraint should be implanted, there is very little in the literature to substantiate this. This study attempts to quantify the influence of constraint and various indications upon functional outcome following aseptic first time revision knee arthroplasty. The null hypothesis was that the level of constraint and indication for surgery would not influence the functional outcome following revision knee replacement. Methods. A single centre prospective study was performed to examine the outcome for 175 consecutive total revision knee replacements performed between 2003 and 2008 with a minimum follow-up of two years. Patient reported outcome data was used to determine the influence of final level of component constraint and its relationship with primary indication for surgery. Results. All patients were found to have a significant improvement for WOMAC pain, function and stiffness score (p< 0.001) and physical functioning, role physical, bodily pain and social functioning components of SF-36 score (p< 0.05). 69% were satisfied with the overall procedure. WOMAC function, pain and stiffness score was significantly worse for patients revised for instability (27%) compared to that for aseptic loosening (46%). A significantly higher proportion of patients were satisfied with the procedure (p< 0.001), had a better quality of life (p=0.004) and would have the surgery (p=0.005) again in the aseptic loosening group as compared to the instability group. Revision to a higher level of constraint did not improve knee function irrespective of the primary indication for surgery. Conclusion. Revision for an instability pattern irrespective of choice of new device was met with significantly poorer functional outcome

Purpose: Total knee arthroplasty is one of the most successful modern surgical interventions with excellent clinical outcomes and implant survivorship. Nevertheless, with the increasing numbers of primary knee replacements being performed and increasing life expectancy, the need for revision arthroplasty continues to grow and is expected to grow considerably in to the future. Stemmed implants are commonly used in revision knee arthroplasty to provide adequate support for the joint interfaces. Controversy exists amongst surgeons as to the relative merits of cemented versus uncemented stems in revision knee arthroplasty. Cementing stemmed components in revision knee arthroplasty surgery is well established, and has well documented success rates. Though in widespread use, there is little data published regarding the technique of cementing short stubby tibial stems in revision TKA. We describe modes of failure in knee arthroplasty, our technique for revision, and early outcomes for this patient cohort. Method: This was a retrospective analysis of a cohort of patients who have undergone revision knee arthroplasty. We evaluated the early clinical results looking for early failure in patients who have undergone revision knee arthroplasty using a short cemented tibial stem. All patients were operated on by a single surgeon in a single hospital. Baseline data was collected on all patients (age, gender, BMI, reason for revision, preoperative knee scores, details of surgery). Latest follow up clinical data, knee scores, and x-rays were evaluated to determine early patient outcomes and identify any implant or technical failure. Results: Between 2003 and 2009, 77 of 241(32%) revision knee arthroplasty surgeries were performed using a short cemented tibial stem. This cohort of 77 patients included 49 females and 27 males. Eight knees (10%) were operated in two stages in the setting of deep infection. Average follow up for this group was 17 months (range 4 to 60 months). One patient developed a deep prosthetic infection requiring further revision surgery. No other patients to our knowledge have undergone further surgery and none have further surgery planned for mechanical failure or significant malalignment of the tibial prosthesis. No failure or early mechanical complication of using a short cemented tibial stem was identified clinically or radiographically. Conclusion: We surmise the use of short cemented tibial stems in revision knee arthroplasty surgery is a safe and effective technique with potential advantages over longer cemented or uncemented stems. We have recorded satisfactory early outcomes, and continue to use this technique

Abstract. Introduction. Our aim was to investigate trends in the incidence rate and main indication for revision knee replacement (rKR) over the past 15 years in the UK. Methodology. Cross-sectional study from 2006 - 2020 using data from the National Joint Registry (NJR). Crude incidence rates were calculated using population statistics from the Office for National Statistics. Results. Annual total counts of rKR increased from 2743 procedures in 2006 to 6819 procedures in 2019 (149% increase). The incidence rate of rKR increased from 6.3 per 100,000 adults in 2006 (95% CI 6.1 to 6.5) to 14 per 100,000 adults in 2019 (95% CI 14 to 14). Annual increases in the incidence rate of rKR became smaller over the study period. The incidence of rKR was highest in patients aged 70–79 years (50 per 100,000 adults [95% CI 48 to 52]). Aseptic loosening was the most frequent indication for rKR overall (20.5% procedures). However, rKR for aseptic loosening peaked in 2012 and subsequently decreased. rKR for infection increased incrementally over the study period to become the most frequent indication for rKR in 2019 (2.7 per 100,000 adults [95% CI 2.6 to 2.9]). Infection accounted for 17.2% first linked rKR, 36.7% second linked rKR and 50.7% third or more linked rKR. Conclusion. Recent trends suggest slowing of the rate of increase in the incidence of rKR. Infection is now the most common indication for rKR, following recent decreases in rKR for aseptic loosening. Infection was prevalent in re-revision KR procedures

Aim: The purpose of this study was to report our experience mid to long-term results of hybrid cement fixation in revision total knee arthroplasty. Methods: Patients who underwent revision total knee arthroplasty using a hybrid cement technique (press-fit diaphyseal fixation and cemented metaphyseal fixation) with a titanium fluted revision knee implant were reviewed. There were 127 patients. Mean age at surgery was 71 years (range 41–94 years). There were 56 males and 71 females. Mean follow-up was 5 years (range, 2–12 years). A Kaplan-Meier survivorship analysis using an end-point of revision surgery or radiographic loosening was employed to determine probability of survival at 5 and 10 years. Results: 127 patients (135 knees), 31 patients (36 knees) died and 2 patients (2 knees) were lost to follow-up. Six patients (six knees) were revised at a mean of 3.5 years (range 1–8 yrs). Of the 6 revisions, two were for re-infection, two were for (MCL) instability, and two were for aseptic loosening. Mean Knee Society clinical and functional scores were 86 and 55 points, respectively. The mean range of motion was 108 degrees. End of stem pain was not reported in this group of patients. Kaplan-Meier survivorship analysis revealed a probability of survival free of revision for aseptic loosening of 98% at 12 years. Discussion: The results of this study suggest that the use of a hybrid cement technique in revision knee arthroplasty can provide good mid to long-term results. Radiographic analysis has shown continued satisfactory appearances regardless of constraint, stem size and augments. Our experience has shown that the survivorship of a hybrid fixation technique for revision knee arthroplasty is comparable to reported long-term survivorship of cemented revision knee arthroplasty

Objectives. The purpose of this study was to develop an accurate, reliable and easily applicable method for determining the anatomical location of the joint line during revision knee arthroplasty. Methods. The transepicondylar width (TEW), the perpendicular distance between the medial and lateral epicondyles and the distal articular surfaces (DMAD, DLAD) and the distance between the medial and lateral epicondyles and the posterior articular surfaces (PMAD, DLAD) were measured in 40 knees from 20 formalin-fixed adult cadavers (11 male and nine female; mean age at death 56.9 years, . sd. 9.4; 34 to 69). The ratios of the DMAD, PMAD, DLAD and PLAD to TEW were calculated. Results. The mean TEW, DMAD, PMAD, DLAD and PLAD were 82.76 mm (standard deviation (. sd. ) 7.74), 28.95 mm (. sd. 3.3), 28.57 mm (. sd. 3), 23.97 mm (. sd. 3.27) and 24.42 mm (. sd. 3.14), respectively. The ratios between the TEW and the articular distances (DMAD/TEW, DLAD/TEW, PMAD/TEW and PLAD/TEW) were calculated and their means were 0.35 (. sd. 0.02), 0.34 (. sd. 0.02), 0.28 (. sd. 0.03) and 0.29 (. sd. 0.03), respectively. Conclusion. This method provides a simple, reproducible and reliable technique enabling accurate anatomical joint line restoration during revision total knee arthroplasty. Cite this article: B. Ozkurt, T. Sen, D. Cankaya, S. Kendir, K. Basarır, Y. Tabak. The medial and lateral epicondyle as a reliable landmark for intra-operative joint line determination in revision knee arthroplasty. Bone Joint Res 2016;5:280–286. DOI: 10.1302/2046-3758.57.BJR-2016-0002.R1

Introduction. Bone loss in the distal femur and proximal tibia is frequently encountered with both complex primary and revision knee replacement surgery. Metaphyseal sleeves provide a good option for enhanced fixation in managing such defects on both the tibia and femur. We present our results in 48 patients (50 knees) with a minimum 12 month follow up (range 12 to 45). Methods. 48 patients (50 knees) who had revision knee arthroplasty for either septic or aseptic loosening. All were graded Type II or III using the Anderson Orthopaedic Research Institute (AORI) grading system of both femoral and tibial defects. A large portion of aseptic loosening revisions were for extreme osteolysis of a bicondylar knee prosthesis. Results. 52% had tibial sleeves only, 38% had both tibial and femoral sleeves and the remainder had only femoral sleeves inserted. All knee radiographs at final follow-up showed well-fixed osteointegrated components without component migration or clinically significant osteolysis. Two knees were treated with multiple arthroscopic washouts for infection. Two knees subsequently underwent manipulation under anaesthesia with good improvement in range of movement. One subsequently developed Complex Regional Pain Syndrome. No femoral or tibial components were revised. The average pre-operative Oxford Knee Score was 22 (12 to 38) and subsequently improved to 38 (12 to 45) post-operatively. Discussion and conclusions. Our early results show encouraging signs that porous titanium sleeves are a good option when managing large metaphyseal bone loss in both femur and tibia especially in revision arthroplasty. Post operative complications were low and functional outcome scores were comparable with more traditional knee revision arthroplasty techniques in the presence of bone loss

Authors have been using kinematic computer navigation for a total knee replacement surgery since 2003. A contribution and advantage of computer navigation is well recognized. Exact guidance of both tibial and femoral osteotomy along with precise soft tissue balance respecting individual anatomic constitution is achieved by exact collection and computer evaluation of data by a use of special sensors and probes. Use of kinematic navigation in experienced hands minimizes deviation from physiological mechanical Mikulicz axis. This is considered the most important step to achieve a good long term outcome after total knee arthroplasty. We have been recently using Brain Lab kinematic navigation system in both primary and revision knee arthroplasties. 200 primary and 20 revision knee arthroplasties are included in the retrospective 3 year follow up study. A navigated revision surgery is recently performed only in cases where the axial deformity does not exceed 10 degrees and where no significant bone loss is presented (bone defects less that ½ cm). Standard cemented components are used in both primary and revision cases. A primary navigated knee arthroplasty had no exclusion criteria in the above study. Technique: Medial patellar approach technique is used, navigation probes are placed in standard distal femoral and proximal tibial position. Data are collected using navigation probes and sensors. Loosen components and cement are removed next. Navigated proximal tibial osteotomy, distal femoral osteotomy and soft tissue balance are performed. Gentamycin cementing of standard components (tibia first) is performed at the end. A final verification of component balance and data storage terminates the procedure. No need for conversion to a revision knee system using stem and wedges was noticed in the above series. Following the above inclusion criteria standard cemented implants were used only. We conclude that the use of navigation in cases of relatively uncomplicated knee revision arthroplasty guaranties good mid term outcome, good soft tissue balance, saves money on expensive knee revision systems and guaranties an alternative of second stage revision surgery with a use of extensive revision systems. Standard implant selection does not apply for those with deep bone defects and axial deformation higher than 10 degrees

The aim of this study was to ascertain if a correlation exists between the indication for revision and the clinical outcome in revision total knee replacement. Methods: We analysed the data of 81 revision knee arthroplasty patients performed at Wrightington Hospital with an average follow-up of 31 months (1yr – 6yrs). All patients had semi-constrained prosthesis implanted (PS-PFC or TC3, Depuy). The indications for revising the total knee arthroplasty in each patient were noted and the clinical outcome was determined using a patient satisfaction questionnaire. Results: Of the 81 patients, 18 were enthusiastic with the clinical outcome, 38 were satisfied, eight were non-committal and 17 were disappointed. Indications for revision in our series were aseptic loosening (31 patients), implant failure (21 patients), instability (14 patients), pain (eight patients) and infection (seven patients). Correlation between the indication for revision and the clinical outcome are detailed in the table below. Sixteen per cent of patients revised for aseptic loosening were non-committal or disappointed with the outcome in comparison with 33.3% revised for implant failure, 21.4% revised for instability, 62.5% revised for pain and 71.4% revised for infection. Conclusion: The indication for revision does affect the clinical outcome in revision knee arthroplasty. Patients undergoing revision knee arthroplasty for infection and pain are less likely to be satisfied with the clinical outcome of revision surgery

It is usually assumed that there is a correlation between the number of previous operations and the clinical outcome of revision knee arthroplasty though it has not been studied and published. We reviewed our series of 81 revision knee arthroplasty patients to ascertain if a correlation exists. All patients had a semi-constrained prosthesis implanted. Methods: We analysed the data of 81 revision knee arthroplasty patients performed at Wrightington Hospital with an average follow-up of 31 months (1yr – 6yrs). The number of previous operations on each knee were noted and the clinical outcome was determined using a patient satisfaction questionnaire. Results: Of the 81 patients; 18 were enthusiastic with the clinical outcome; 38 were satisfied; eight were non-committal; 17 were disappointed. Seventy four per cent of patients with one previous operation were enthusiastic or satisfied with the revision surgery outcome in comparison to 55.5% and 0% of patients with two and three previous surgery respectively. Conclusion: The trend from the above figures suggests that as the number of previous operations increases the likelihood of satisfactory clinical outcome decreases, in revision total knee replacement using semi-constrained prosthesis

The prospective evaluation of two hundred and seven symptomatic total knee arthroplasties presenting for revision total knee arthroplasty is reported. On univariate analysis patients who had infection differed significantly (p< .001) from those without infection with regards to: elevated ESR, CRP, positive aspiration, and history of; revision procedure less than two years since last surgery, early wound problems, ongoing pain since index procedure, and discharging wound. On multivariate analysis elevated ESR or CRP, positive aspiration, pain since index procedure and early wound complications were significant predictors of infection (p< .05). These variables were then used to formulate an evidence-based multivariate predictive algorithm to assist the clinician in decision making prior to surgery. Differentiating septic from aseptic failure of total knee arthroplasty on the basis of clinical features and diagnostic tests can be troublesome for the clinician. The purpose of this paper is to describe significant differences between cases of septic and aseptic failure of total knee arthroplasty. The incorporation of these variables into a practical multivariate clinical prediction algorithm can provide assistance in establishing the diagnosis of infection prior to revision knee arthroplasty. A simple clinical prediction algorithm can assist in the diagnosis of infection in patients with painful total knee arthroplasty. Patients with five of five criteria have a 99% probability of infection whereas patients with zero of five criteria have a 1% probability of infection. This is the first multivariate evidence-based clinical prediction algorithm presented for use in decision making prior to revision total knee arthroplasty. The surgeon can use the information derived from clinical and laboratory assessment to compute an approximate pre-operative probability of infection prior to surgery (see table). On multivariate analysis elevated ESR or CRP, positive aspiration, pain since index procedure and early wound complications were significant predictors of infection (p< .05). These variables were then used to formulate an evidence-based multivariate predictive algorithm to assist in clinical decision making. Prospective data was collected on two hundred and seven symptomatic knee arthroplasties presenting for revision arthroplasty. A multivariate logistic regression model was used to determine the probability of infection using five significant variables. Combinations of these five variables can provide the clinician with an estimate of the probability of infection prior to revision knee arthroplasty. Please contact author for tables and/or charts

Aims: To determine the kneeling ability in 3 groups of patients who have undergone either Unicondylar, Primary, or Revision knee arthroplasty. Methods: A questionnaire was designed to determine the kneeling ability of patients who have undergone knee arthroplasty surgery. The ‘Kneeling’ questionnaire along with a Western Ontario and MacMaster Osteoarthritis Index (WOMAC) questionnaire was sent to 191 patients of whom, 27 have had Unicondylar, 105 had Primary and 59 Revision knee arthroplasty. Results: The mean follow-up time for assessment for each of the 3 groups of patients were; Unicondylar = 3.32 years, Primary = 5.30 years and Revision = 5.06 years. The mean total WOMAC scores for the 3 groups were; Unicondylar = 13.96, Primary = 22.10, and Revision = 38.67. The percentage of patients who underwent knee arthroplasty that found it impossible to kneel were; Unicondylar = 18%, Primary = 36% and Revision = 66%. The commonest reasons why patients found kneeling difficult were; pain and stiffness around the knee prosthesis, fear of harming the prosthesis and sensory deficit around the knee. Visual Analogue Pain scores for kneeling in the 3 patient groups were, Unicondylar = 5.6, Primary = 7.12, Revision = 9.18. A minimum of 30% of patients in each of the 3 groups reported their daily lives were moderately-severely affected due to their difficulty in kneeling following knee arthroplasty. At least 60% of the patients in each group reported they would like to have better kneeling ability. Conclusion: Unicondylar knee arthroplasty patients have better WOMAC scores and find kneeling easier than patients who have undergone Primary knee arthroplasty (p< 0.01). The Primary group have better WOMAC scores and find kneeling easier than the Revision group (p< 0.001). Kneeling is considered important in patients who have undergone knee arthroplasty. Poor kneeling ability in patients may restrict their daily activities

Aim: To report our experience of revision knee arthroplasty with respect to surgical technique, joint line restoration and clinical outcome. Methods: A clinical and radiological review was made of 45 knee revisions performed between 1996 to1998 using the Kinemax system. The reasons for revisions were infection (19), wear (11), loosening (seven), base-plate fracture (four) and instability (five). A primary prosthesis was used in 10 (22%), a posterior stabiliser in 24 (53%) and a superstabiliser in 11 (24%). WOMAC pain and function scores, arc of motion and measurements of joint line and patellar height were made. Results: Three patients had died. Three knees had been revised a second time for instability and one had been arthrodesed for infection. The mean joint line elevation was 1.3mm compared with the primary and depressed 1.6mm when compared with the natural knee. Twenty-seven percent had patella infera and 13% had patella alta. A significant correlation was found between the change in patellar tendon length and the change in the joint line. The flexion arc was significantly improved from 83 degrees to 95 degrees. No relationship was found between the clinical outcomes and the changes in the joint-line. There were two deep infections (4.4%) and five knees were unstable. The three cases of flexion instability were due to failure to reconstruct adequately the antero-posterior (AP) diameter of the femur. Conclusions: By restoring the level of the joint-line, a less constrained prostheses can be used in revision surgery with good functional results. The AP diameter of the femur must also be reconstructed to avoid flexion instability