Revision Total Knee Replacement Research Articles

Is constraint implant with metaphyseal sleeve a viable option for revision TKR with preoperative coronal plane instability and bone defect?

Metaphyseal sleeves have been used as metaphyseal filling implants to address bone loss during revision total knee replacements (TKRs). This study aims to compare the 2-year clinical and radiological outcomes of constraint implant with bone defect and constraint implant without or minimal bone defect in revisions TKR with preoperative coronal plane instability. Seventeen cases of constraint implants with metaphyseal sleeve matched paired with 34 cases of constrained condylar knee (CCK) prosthesis. Age, gender, body mass index and aetiology for revision surgery were recorded. Clinical outcome measures included Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), Oxford Knee Score (OKS), physical component summary (PCS) and mental component summary (MCS). Radiological outcome measures included joint line changes, hip-knee-ankle angle (HKA), coronal femoral angle (CFA) and coronal tibial angle (CTA). Patients in sleeve group showed significant improvement in KSKS, KSFS and OKS (38 ± 7, 35 ± 6 and 20 ± 2 points, respectively, p < 0.001), while they were 19 ± 3 and 6 ± 2 points for PCS and MCS, respectively (p < 0.001 and p = 0.021). These postoperative scores after surgery were similar between the two groups at 6 months and 2 years. The sleeve provides comparable result in joint line restoration; the postoperative HKA, CFA and CTA were all comparable between the two groups. Metaphyseal sleeve with constraint implant is a viable option for revision TKR with preoperative coronal plane instability and significant bone defect. It is able to achieve similar clinical outcomes and joint line restoration compared to CCK prosthesis at 2-year follow-up.

Is it Possible to Treat Insert Dislocation With a Fixed Insert Tibial Component After Primary Oxford Phase 3 Mobile Unicompartmental Knee Arthroplasty?

Background: The aim of this study was to investigate the clinical and radiologic outcomes of patients who underwent the revision surgery of tibial component replacement using fix-insert in the cases of Oxford phase 3 medial unicompartmental knee arthroplasty with insert dislocation after initial insert replacement. Materials and Methods: Nine patients who experienced insert dislocation after insert replacement and who underwent partial replacement revision (tibial component revision) were included in this study. Demographic data and complications of these patients were evaluated. Clinical outcomes were determined through Knee Society Score and Functional Knee Society Score. Results: Insert redislocation happened in 11 of 17 patients whose insert was already replaced after initial insert dislocation. Among 11 patients, 2 patients underwent primer and revision total knee replacement revision surgery due to gap inequality and medial collateral ligament deficiency. In the other 9 patients, partial tibal component revision was performed. The mean follow-up time for the patients was 44.4 (21 to 76) months. The mean Knee Society Score/Functional Knee Society Score scores were 80.1 (72 to 95)/78.6 (70 to 90) and 79.5 (72 to 90)/77.5 (68 to 90) at the final follow-up after partial revision and before the insert dislocation, respectively. There was no decline in clinical scores and no revision was required in the mid-term follow-up. Conclusions: In this study, we found that there was no worsening in the clinical scores of the patients in the mid-term and no revision was required following the treatment of redislocation through tibial component revision. It was concluded that partial revision treatment with a fixed insert tibial component in the case of insert redislocation does not increase morbidity and could be an ideal treatment option. However, this conclusion should be further supported by multicenter studies along with the high number of cases. Level of Evidence: Level IV—retrospective case-control study.

Tranexamic acid decreases the risk of revision for acute and delayed periprosthetic joint infection after total knee replacement.

Objectives This study aims to analyze the effect of intravenous administration of tranexamic acid (TA) on reducing the risk of revision for acute and delayed periprosthetic joint infection (PJI) after primary total knee replacement (TKR).Patients and methods This prospective observational cohort study included 1,529 TKRs (396 males, 1,133 females; mean age 67.8 years; range, 44 to 85.1 years) performed between January 2003 and October 2017. We analyzed the revision rate for acute and delayed PJI in a group of 787 TKRs with preoperatively intravenously administered TA (TA group) in comparison with a group of 742 TKRs without administration of TA (non-TA group). Multiple logistic regression analysis was used to evaluate significant predictors of TKR revision for acute and delayed PJI.Results Revision surgery due to PJI was recorded in one patient in the TA group and eight patients in the non-TA group. Cumulative revision rate of TKR was significantly lower in the TA group (0.13% vs. 1.08%, hazard ratio 0.113; 95% confidence interval [CI] 0.0147-0.937; p=0.043). Multivariate logistic regression analysis confirmed two predictors of revision: being aged over 75 years at the time of primary surgery (odds ratio [OR] 8.464; 95% CI: 2.016-35.54; p=0.004) and male gender (OR: 7.9; 95% CI: 1.879-33.26; p=0.005). The use of TA was shown as the significant protective factor (OR: 0.109; 95% CI: 0.0128-0.929; p=0.043).ConclusionWe have found a lower cumulative revision rate of TKR for acute and delayed PJI when TA was used. We think that the preoperative intravenous use of TA may be an effective, safe and inexpensive method for the prevention of PJI.

Racial Disparities in Total Knee Replacement Failure As Related to Poverty.

To determine whether racial disparities in total knee replacement (TKR) failure are explained by poverty. Black and white New York state residents, enrolled in a prospective single-institution TKR registry January 1, 2008 to February 6, 2012, who underwent primary unilateral TKR (n = 4,062) were linked to the New York Statewide Planning and Research Cooperative System database (January 1, 2008 to December 31, 2014) to capture revisions performed at outside institutions. Patients were linked by geocoded addresses to residential census tracts. Multivariable Cox regression was used to assess predictors of TKR revision. Multivariable logistic regression was used to analyze predictors of TKR failure, defined as TKR revision in New York state ≤2 years after surgery, or as Hospital for Special Surgery (HSS) TKR quality of life score "not improved" or "worsened" 2 years after surgery. The mean ± SD age was 68.4 ± 10 years, 64% of patients were female, 8% lived in census tracts with >20% of the population under the poverty line, and 9% were black. Median follow-up time was 5.3 years. A total of 3% of patients (122 of 4,062) required revision a median 454 days (interquartile range 215-829) after surgery. TKR revision risk was higher in blacks than whites, with a hazard ratio of 1.69 (95% confidence interval 1.01-2.81), but in multivariable analysis, only younger age, male sex, and constrained prosthesis were predictors of TKR revision. TKR failure occurred in 200 of 2,832 cases (7%) with 2-year surveys. Risk factors for TKR failure were non-osteoarthritis TKR indication, low surgeon volume, and low HSS Expectations Survey score, but not black race. Community poverty was not associated with TKR revision or failure. There was a trend toward higher TKR revision risk in blacks, but poverty did not modify the relationship between race and TKR revision or failure.

Résultats du traitement chirurgical des fractures interprothétiques

IntroductionInterprosthetic fractures occur between a total knee replacement and a femoral stem of either a hemiarthroplasty or total hip replacement. The number of interprosthetic fractures will increase as the number of joint replacements rises. There is currently a paucity of literature looking at the outcomes of interprosthetic fractures. Therefore, we performed a retrospective study to: (1) Determine fracture union in patients following surgical treatment of a femoral interprosthetic fracture, (2) measure outcomes included mortality and complications. HypothesisFavouring bone fixation instead of prosthetic revision gives an acceptable rate of re-operation. Materials and MethodsA retrospective case note review of all interprosthetic femoral fractures admitted to a tertiary trauma centre over a 7-year period. There were 24 patients (4 males and 20 females) with a mean age of 82.3 (65–98). The initial operative procedure was a total hip replacement (THR) and a total knee replacement (TKR) in 19 patients, one THR and revision TKR, four hip hemiarthroplasty and TKR. There were 23-cemented femoral stems, and 1 uncemented femoral stem. The median time to surgery was 84hours. The median length of hospital stay was 16 days. Nineteen patients underwent open reduction internal fixation and 1 of these used a strut graft. Two patients underwent revision knee replacements and 3 underwent a revision hip replacement. All patients had at least 2 years clinical follow-up. ResultsOne patient died within 30 days of fracture, leaving 23 patients to assess bone union. Another patient died within 1 year of fracture. Three out of 24 patients (12.5%) suffered a complication that required further surgery. The fracture united in 19/23 (82.6%) of patients and the two-year mortality rate was 5/24 (20.8%). DiscussionInterprosthetic fractures are complex fractures occurring in elderly patients with multiple medical comorbidities. Whenever possible bone fixation instead of prosthetic revision give a low rate of complication and re-operation. The surgical treatments are complex, but with a well-performed surgical technique and an adequate rehabilitation program can result in satisfactory outcomes. Level of evidenceIV, Retrospective Case series.

Impact of patient comorbidities on surgical site infection within 90 days of primary and revision joint (hip and knee) replacement

The frequency of primary and revision total knee and hip replacements (pTKRs, rTKRs, pTHRs, and rTHRs, respectively) is increasing in the United States due to demographic changes. This study evaluated the impact of preoperative patient and clinical factors on the risk of surgical site infection (SSI) within the 90-day period after primary and revision total joint replacements (TJR). A retrospective observational cohort study was designed using the IBM MarketScan and Medicare databases, 2009-2015. Thirty-four comorbidities were assessed for all patients, and multivariable logistic regression models were used to evaluate factors associated with higher odds of SSI after adjusting for other patient and clinical preoperative conditions. The study included a total of 335,134 TKRs and 163,547 THRs. SSI rates were 15.6% and 8.6% after rTKR and rTHR, respectively, compared with 2.1% and 2.1% for pTKR and pTHR, respectively. Comorbidities with the greatest adjusted effect on SSI across all TJRs were acquired immunodeficiency syndrome (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.06-2.34; P = .0232), paralysis (OR, 1.56; 95% CI, 1.26-1.94; P < .0001), coagulopathy (OR, 1.48; 95% CI, 1.36-1.62; P < .0001), metastatic cancer (1.48; 95% CI, 1.24-1.76; P < .0001), and congestive heart failure (OR, 1.39; 95% CI, 1.30-1.49; P < .0001). SSI occurred most commonly among patients after revision TJR and were related to many patient comorbidities, including diabetes, congestive heart failure, and coagulopathy, which were significantly associated with a higher risk of SSI after TJR.

PSU35 TOTAL KNEE REPLACEMENT: RISK AND BURDEN OF POST-SURGICAL DEEP AND SUPERFICIAL INFECTION

Primary total knee replacement (P_TKR) is a common procedure with low complication rates. However, revision TKR (R_TKR) is associated with significantly greater risks. This study was thus designed to understand risk of infection (deep and superficial) and associated costs for patients presenting with either P_TKR or R_TKR. A retrospective study of patients undergoing P_TKR or R_TKR between 2014 and 2017 was conducted using IBM® MarketScan® Commercial, Multi-State Medicaid and Medicare Supplemental databases. Patients were categorized by demographic and clinical comorbidities as per the 31 domains of the Elixhauser Comorbidity Index. The outcome were new diagnoses of infection, categorized as deep and superficial within 6 months of surgery. Logistic regression models were evaluated to determine variables associated with infection. Generalized linear regression models were built and adjusted total payments due to infection by category were estimated using least squares means. All payments were adjusted to 2017 consumer price-index. A total of 153,335 P_TKR and 10,429 R_TKR patients were included in the analysis. Mean age and percentage female was 63 years (SD: 9.7), 62 years (SD: 10.6) and 62.6%, 63.0% in the P_TKR and R_TKR cohorts, respectively. Overall 5.9% P_TKR and 16.4% R_TKR patients presented with any infection (deep infection: 2.2% in P_TKR and 11.4% in R_TKR). Adjusted total payments in patients with commercial insurance ranged from $97,014 (95% CI: $93,466- $100,697) for superficial to $121,805 (95% CI: $116,103-$127,787) for deep infection in P_TKR. For R_TKR, payments ranged from $126,527 (95%CI: $109,495-$146-208) to $137,270 (95%CI: $126,180-$149-334). Key variables associated with infection included age and psychoses for P_TKR and; metastatic cancer and drug abuse for R_TKR. Revision TKR patients face a nearly 5-fold greater risk of deep infection than primary TKR. Strategies such as SSI prevention bundle to help address the risk of infections should be considered.

Severe metallosis-related osteolysis as a cause of failure after total knee replacement

BackgroundMetallosis is a syndrome of metal-induced synovitis caused by friction between two metal surfaces. In contrast to the hip joint after resurfacing arthroplasty or metal-on-metal (MoM) total hip replacement, metallosis of the knee is extremely rare. MaterialsWe describe 4 patients who underwent revision total knee replacement because of disabling pain and implant loosening after a mean time of 21 (range: 13–30) years of knee replacement surgery. They were all females with a mean age of 79 (range: 75–82) years. Septic loosening was excluded through microbiological examination and synovial fluid analysis. ResultsDirect metal-on-metal contact at the tibiofemoral interface was confirmed intraoperatively in all cases. All knees showed severe metallosis with advanced osteolysis and pseudotumor formation. In one knee there was a complete fracture of the tibial tray. All patients had a one-stage revision surgery with implant removal, profound synovectomy and implantation of a constrained modular revision knee system. Long modular stems with offset adapters, wedges and/or blocks were used in all cases. ConclusionMetallosis-associated osteolysis should be suspected in cases with radiologically evident polyethylene wear after knee replacement. Recognizing that revision arthroplasty is very technically demanding in such cases, surgeons should have a back-up with modular revision components and a ready access to reconstructive options at this revision setting.

Influence of stems and metaphyseal sleeve on primary stability of cementless revision tibial trays used to reconstruct AORI IIB defects.

Metaphyseal augments, such as sleeves, have been introduced to augment the fixation of revision total knee replacement (rTKR) components, and can be used with or without a stem. The effect of sleeve size in combination with stems on the primary stability and load transfer of a rTKR implant in AORI type IIB defects where the defect involves both condyles are poorly understood. The aim of this study was to examine the primary stability of revision tibial tray augmented with a sleeve in an AORI type IIB defect which involves both condyles with loss of cortical and cancellous bone. Finite element models were generated from computed tomography (CT) scans of nine individuals. All the bones used in the study had an AORI type IIB defect. The cohort included eight females (mean weight: 64 kg, height: 1.6 m). Material properties were sampled from CT data and assigned to the FE model. Joint contact forces for level gait, stair descent, and squat were applied. Stemless sleeved implants under various loading conditions were shown to have adequate primary stability in all AORI type IIB defects investigated. Adding a stem only marginally improved the primary stability of the implant but reduced the strain in the metaphysis compared to stemless implants. Once good initial mechanical stability was established with a sleeve, there was no benefit, in terms of primary stability or bone strains, from increasing sleeve size. This study suggests that metaphyseal sleeves, without a stem, can provide the required primary stability required by a rTKR tibial implant, to reconstruct an AORI type IIB defect. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Projecting the healthcare burden of knee osteoarthritis in New Zealand: results from a computer simulation model

Purpose: To forecast the demand for total knee replacement (TKR) surgery and total healthcare expenditure due to knee osteoarthritis (OA) in the New Zealand (NZ) population over the period 2013 to 2043. Methods: We projected the incidence and progression of knee OA, utilization of TKR, and total knee OA-related healthcare expenditure in NZ over 30 years using the Osteoarthritis Policy (OAPol) model. The OAPol model is a computer-based, state-transition, Monte Carlo simulation model that can be used to estimate the projected rates of TKR, health loss, and healthcare spending associated with knee OA.The starting population cohorts in the model were defined by five-year age groups (from 25-29 years up to 75-79 years, and 80 years and over), stratified by ethnicity (Māori or non-Māori), BMI (obese or non-obese), and sex, based on the 2013 NZ population distribution (Census data). Simulated individuals with knee OA pass through up to four regimens in the standard treatment sequence in the model: NSAIDs and physical therapy, corticosteroid injections, TKR, and revision TKR. Data for the costs and utilization of these treatment regimens were obtained from a variety of NZ and international sources. The rate at which patients were offered and accepted TKR was calibrated to TKR provision rates drawn from the New Zealand Joint Registry, by running the model for 5 years and varying the offer and acceptance rates to match actual provision for each cohort.The OAPol model was used to project the proportion of individuals receiving TKR and per-capita OA-related healthcare costs for each five-year period from 2013-2018 to 2038-2043, within the population cohorts stratified by age, sex, obesity, and ethnicity. These rates were then applied to projected population sizes, obtained from Statistics New Zealand population projections and previously-published projections of obesity prevalence rates, to forecast the total burden of OA in each five-year period. As the youngest (25-29 years) cohort would be aged 50-54 at the start of the final (2038-2043) period, we have analysed TKR provision projections for those aged 50 years and over at the start of each period (to ensure an equivalent cohort in each period). Results: The total provision of TKR was projected to increase rapidly from 5400 per year in 2013-2018 to 6800 per year in 2018-2023, and then more slowly to 7300 per year in 2038-2043 (Figure 1). These increases largely reflected projected growth in the size of the older population, with the annual rate of TKR provision in those aged 50 years and over peaking at 410 per 100,000 population in 2018-2023, before falling to 330 per 100,000 in 2038-2042. This trend occurs because the number of TKRs received by those with initial prevalent knee OA (at baseline) rapidly falls away after 2018-2023, as many people in this cohort are by then projected to have either already had a TKR or died.OA-related treatment costs were estimated to be NZ$156 million per year in 2013-2018 (1 NZD ≈ 0.82 USD in 2013), and NZ$8.0 billion (in present-value terms, discounted at 3% per annum) over the 30-year time horizon.After adjusting for differences in the baseline age distribution, Māori had a substantially higher burden of OA, in terms of both TKR utilization and OA healthcare costs (Figure 2). Conclusions: Knee OA inflicts a growing cost to the NZ healthcare system. The projected rapid increase in demand for TKR over the next decade will require additional healthcare resources, to an environment in which the provision of joint replacement within the public healthcare sector is already constrained by capacity limitations.Our estimates of the treatment costs associated with OA, while substantial, represent underestimates of the true cost to the health system and society. Only costs associated with the four treatment regimens (NSAIDs and physical therapy, corticosteroid injections, TKR, and revision TKR) have been modelled, and only for the index knee (the model does not capture contralateral TKRs). Furthermore, indirect and non-healthcare costs (such as lost earnings, informal sector care, and community care) have not been considered. These projections indicate a need for a comprehensive national OA strategy in NZ to manage the demands that an ageing population, with increasing OA prevalence and obesity, will place on the NZ healthcare system.Figure 2Healthcare cost and total joint replacement provision in New Zealand, by age and ethnicity, 2013-20432View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Three-phase Technetium-99m bone scanning in patients with pain in the knee region after cemented total knee arthroplasty.

Our aim was to question the usefulness of a three-phase bone scan in the evaluation of pain in the knee region after TKR. Our hypothesis was that an abnormal investigation had a poor association with the presence of infection or loosening, and did not provide any additional diagnostic information above that already available through other standard investigations. A retrospective study over a 24-month period was performed comprising 118 patients investigated with a TPBS. Investigations were summarised and analysed, and were classified as entirely normal, possibly abnormal, and definitely abnormal. Thirty-three per cent (39/118) of TPBSs were reported as being entirely normal, 59% (69/118) as possibly abnormal, and 8% (10/118) as definitely abnormal. During the 24-month study period, 131 revision TKR procedures were performed at our institution; 9% (12/131) were investigated with TPBS and 91% (119/131) were not. No patient with an entirely normal pre-operative TPBS underwent revision TKR surgery. Eighty-five per cent (67/79) with an abnormal TPBS were managed conservatively. In our series, a TPBS had a positive predictive value of 2.53%, a negative predictive value of 100%, with an overall accuracy of 34.75% with 100% sensitivity (97.5% one-sided confidence interval 0-24.71%), and 33.62% specificity (95% confidence interval 53.29-72.37%), in the diagnosis of infection, or loosening with concurrent infection in determining the indication for revision surgery. A TPBS should only be considered following clinical evaluation, serological investigation, diagnostic imaging, and microbiological analysis of fluid obtained from arthrocentesis by a specialist revision arthroplasty surgeon. A TPBS may be useful in the situation where abnormal serology is present, but where repeated joint aspirations samples are inconclusive.

Revision knee complexity classification-RKCC: a common-sense guide for surgeons to support regional clinical networking in revision knee surgery.

There is considerable variation in practice throughout Europe in both the services provided and in the outcomes of Revision Knee Surgery. In the UK, a recent report published called get it right first time (GIRFT) aims to improve patient outcomes through providing high quality, cost-effective care, and reducing complications. This has led to the development of a classification system that attempts to classify the complexity of revision knee surgery, aiming to encourage and support regional clinical networking. The revision knee classification system (RKCC) incorporates not only complexity, but also patient factors, the presence of infection, the integrity of the extensor mechanism, and the soft tissues. It then provides guidance for clinical network discussion. Reliability and reproducibility testing have been performed to establish the inter- and intra-observer variabilities using this classification. Good correlation between first attempt non-expert and experts, good intra-observer variability of non-expert, and an excellent correlation between second attempt non-expert and experts has been achieved. This supports the use of RKCC by both inexperienced and experienced surgeons. The revision knee complexity classification has been proposed that offers a common-sense approach to recognize the increasing complexity in revision TKR cases. It provides a methodological assessment of revision knee cases and support regional clinical networking and triage of appropriate cases to revision units or specialist centres. Expert opinion, Level V.

Computer-assisted Surgery in Revision Total Knee Replacement: A Description of the Technique

Revision total knee replacement is an increasing problem worldwide. The technical challenges involved in revision surgery, especially with component placement, have drawn attention to computer navigation techniques which have been shown to improve outcomes in the primary setting. We present a detailed description of our preoperative planning and operative technique, and results of our prospective case series.

Outcome of revision UKR to TKR when compared to a matched group of TKR of same total arthroplasty lifespan

AimTo compare outcomes of revision uni-compartmental knee replacement (UKR) with a defined revision cause with a matched group of primary total knee replacements (TKR). BackgroundUKR accounts for 8.7% of knee arthroplasty in the UK each year. It has better functional outcome than total knee replacement for isolated single compartment arthritis but can result in complex surgery when revision is required. This is feared to result in poorer patient reported outcomes when compared to primary TKR. We aim to compare the clinical results of revised UKR with primary TKR, taking into account the survival length of the UKR. Patients and methodsForty-five patients (27 female) were retrospectively identified from our arthroplasty database that had undergone revision from UKR to TKR (1999–2014) and had a minimum of two years of follow-up post-revision. These patients were then matched with regards to age at primary procedure, sex, BMI and total arthroplasty life (UKR + Revision TKR) up to point of follow-up. ResultsIn the UKR revision group (mean arthroplasty life 8.6 years) the mean Oxford knee score (OKS) was 31.8. In the primary knee group (mean arthroplasty life 8.4 years) the mean OKS was 32.8. This difference was not statistically significant. Fifteen out of 45 patients undergoing revision surgery required stemmed components. ConclusionUKR provides comparable clinical outcome even after revision surgery to TKR as primary TKRs and should be considered in all patients meeting the selection criteria. Revision is complex and revision components should be available.

Outcome of surgical treatment of inter prosthetic fractures: A case series

IntroductionInterprosthetic fractures occur between a total knee replacement and a femoral stem of either a hemiarthroplasty or total hip replacement. The number of interprosthetic fractures will increase as the number of joint replacements rises. There is currently a paucity of literature looking at the outcomes of interprosthetic fractures. Therefore, we performed a retrospective study to: (1) determine fracture union in patients following surgical treatment of a femoral interprosthetic fracture, (2) measure outcomes included mortality and complications. HypothesisFavoring bone fixation instead of prosthetic revision gives an acceptable rate of reoperation. Materials and methodsA retrospective case note review of all interprosthetic femoral fractures admitted to a tertiary trauma centre over a 7-year period. There were 24 patients (4 males and 20 females) with a mean age of 82.3 (65–98). The initial operative procedure was a total hip replacement (THR) and a total knee replacement (TKR) in 19 patients, one THR and revision TKR, four hip hemiarthroplasty and TKR. There were 23 cemented femoral stems, and 1 uncemented femoral stem. The median time to surgery was 84hours. The median length of hospital stay was 16 days. Nineteen patients underwent open reduction internal fixation and 1 of these used a strut graft. Two patients underwent revision knee replacements and 3 underwent a revision hip replacement. All patients had at least 2 years clinical follow-up. ResultsOne patient died within 30 days of fracture, leaving 23 patients to assess bone union. Another patient died within 1 year of fracture. Three out of 24 patients (12.5%) suffered a complication that required further surgery. The fracture united in 19/23 (82.6%) of patients and the 2-year mortality rate was 5/24 (20.8%). DiscussionInterprosthetic fractures are complex fractures occurring in elderly patients with multiple medical comorbidities. Whenever possible bone fixation instead of prostehtic revision give a low rate of complication and reoperation. The surgical treatments are complex, but with a well-performed surgical technique and an adequate rehabilitation program can result in satisfactory outcomes. Level of evidenceIV, retrospective case series.

Revision for Aseptic Loosening of Primary Total Knee Arthroplasty

Background: the modes of failure of total knee replacement(TKR) can be classified as intra-articular or extraarticular, as biological or mechanical, as early or late. Aseptic loosening is one of leading cause of failure of total knee replacement. Purpose: it was to spot light on different surgical strategies; to assess the results of 20 cases of revision total knee arthroplasty after aseptic loosening of primary total knee arthroplasty. Materials and Methods: this is a prospective interventional study which was conducted during the period from June 2016 to April 2019 with mean follow up two years. It included 20 patients (20 knees) which were undergone for revision TKR due to aseptic loosening of knee prosthesis. These cases were operated at Al-Azhar University hospitals (Al Hussein & Bab El Shaeria). Results: the average knee society score (KSS) was 79 (range from 55 to 94) compared with an average preoperative KSS of 38 (range from 28 to 48). The mean knee function score at the last follow up was 72 (range from 35 to 95) compared with the mean preoperative knee function score of 31 (range from 10 to 55). Conclusions: results of revision TKA due to polyethelene (PE) wear and its resultant osteolysis were mostly satisfactory to the patients

Revision for Aseptic Loosening of Primary Total Knee Arthroplasty

Background: the modes of failure of total knee replacement(TKR) can be classified as intra-articular or extraarticular, as biological or mechanical, as early or late. Aseptic loosening is one of leading cause of failure of total knee replacement. Purpose: it was to spot light on different surgical strategies; to assess the results of 20 cases of revision total knee arthroplasty after aseptic loosening of primary total knee arthroplasty. Materials and Methods: this is a prospective interventional study which was conducted during the period from June 2016 to April 2019 with mean follow up two years. It included 20 patients (20 knees) which were undergone for revision TKR due to aseptic loosening of knee prosthesis. These cases were operated at Al-Azhar University hospitals (Al Hussein & Bab El Shaeria). Results: the average knee society score (KSS) was 79 (range from 55 to 94) compared with an average preoperative KSS of 38 (range from 28 to 48). The mean knee function score at the last follow up was 72 (range from 35 to 95) compared with the mean preoperative knee function score of 31 (range from 10 to 55). Conclusions: results of revision TKA due to polyethelene (PE) wear and its resultant osteolysis were mostly satisfactory to the patients

Effects of knee simulator control method and radiation dose on UHMWPE wear rate, and relationship between wear rate and clinical revision rate in National Joint Registry

The wear rate of five types of cruciate-retaining artificial knee joint ultrahigh-molecular-weight polyethylene (UHMWPE) inserts was examined using two custom-made knee joint simulators satisfying ISO 14243–1 (load control) and ISO 14243–3 (displacement control). The wear rate of knee joints composed of a UHMWPE insert and a Co-Cr-Mo alloy or oxidized zirconium femoral component linearly increased with increasing number of wear cycles, and the volumetric wear rate per million cycles was approximately 6–18 mm3/Mc. The wear rate was the lowest in the highly crosslinked knee joint irradiated at 90 kGy (Scorpio) among the five UHMWPE inserts. The extent of oxidation in UHMWPE after a knee simulator test of up to 5 × 106 cycles was small. The load-controlled wear rates measured in this work were close to the displacement-controlled wear rates reported in the literature. The effect of the control method on the wear rate was small for Nexgen and Scorpio knee joints. However, it was larger for the PFC Sigma knee joint having a high curvature of the surface. The wear rate of various knee joints made of highly crosslinked UHMWPE (XLPE) markedly decreased when they were subjected to a radiation dose of 40 kGy or more. The 10-year cumulative percentage revision rate since the primary operation slightly decreased with decreasing volumetric knee simulator wear rate for conventional UHMWPE (CPE) and XLPE knee joint inserts. The XLPE knee joint was shown to exhibit reduced in vivo wear and lower rates of revision for total knee replacement. On the other hand, Nexgen and PFC Sigma (both CPE) knee joints showed the lowest revision rate in the AOA and NJR national joint replacement registries. The volumetric wear rates of 3 mm3/Mc for XLPE and 15 mm3/Mc for CPE knee joint inserts are recommended as a goal for the development of new knee joints.

Functional outcome of patellar resurfacing vs non resurfacing in Total Knee Arthoplasty in elderly: A prospective five year follow-up study

IntroductionOsteoarthritis of knee is one of the most common orthopaedic problems of elderly. Total knee arthroplasty is a common surgical procedure. Many of the poor functional outcomes are related to problems of patellofemoral joint and there is considerable debate whether patella should be resurfaced or not at the time of total knee arthroplasty. Material & methodsA total of 100 subjects were evaluated and were further randomized equally into two arms by using standard computer generated random table. Each arm was designated to either RS or Non RS between June 2011 to May 2013 at Department of Orthopaedic Surgery, Goa Medical College and Hospital followed by approval of ethical committee. Exclusion criteria for the study included history of patella fracture, age <50 years, Patellofemoral instability, Prior patellectomy, Prior knee replacement surgery, Prior hip replacement surgery, Patient with osteoarthritis of hip, Prior history of tibial condyle or distal femoral fractures. Chi square test was used for statistic analysis. ResultsKnee society score including clinical and functional (KSS) were performed for assessment. There were a total of 80 female and 20 male patients. Out of 80 female knees, 41 were resurfaced and 39 were not. Out of 20 male knees, 9 were resurfaced and 11 were not. Mean clinical knee score ranging from 0 to 100 points in the resurfaced group improved from 28.6 to 84.14 and; from 24.72 to 86.2 in the non resurfaced group. The difference in the clinical knee score amongst resurfaced and non resurfaced group was not statistically significant at 5 years follow up. The mean functional knee score on a range of 0–100 point went up from 39.1 to 90.1 in resurfaced group and; from 45 to 92.4 in the non resurfaced group. The difference in functional knee score amongst resurfaced and non resurfaced groups is not statistically significant even at 5 years follow up post operatively. However NRS group received better increment in scores than RS group. Visual Analogue Scale (VAS) was used for anterior knee pain assessment pre and post operatively in both groups and was not statistically significant as well. None of the patients underwent revision of total knee replacement after the primary procedure. ConclusionA similar knee evaluation score was observed in both RS and NRS groups after 5 year of follow up. However, it appears that non-resurfacing had shown marginally better scores than resurfacing group.

Failure and Fatigue Fracture at the Femoral Stem-Metaphyseal Sleeve Junction in a Modular Knee Prosthesis

A 66-year-old active man had undergone revision total knee replacement surgery with a femoral metaphyseal sleeve and a cemented stem in 2013 after loosening of the implant following the primary knee arthroplasty. He was overweight and had a high activity level, and there had been progressive osteolysis surrounding the distal aspect of the femoral sleeve. In 2017, the metaphyseal sleeve had loosened, resulting in corrosion of the threaded taper and catastrophic failure of the implant, with a fracture of the stem at the junction of the sleeve. This unique method of failure in this knee implant highlights a weak point in the design. Clinicians must be aware of the increased likelihood of this type of failure with these implants in patients who have contributory factors.