Primary Total Knee Replacement Research Articles

Body mass index and knee arthroplasty

Objectivethis study aims to evaluate the relationship between body mass index (BMI), age at which knee joint arthroplasty is performed and complications. The hypothesis is that the higher the BMI, the greater likelihood that the patient will require surgery at an earlier age.Methods: this is a cohort study with all patients who underwent a primary knee arthroplasty, between August 2013 and February 2019, in a tertiary level university hospital. Association between BMI, age and complications were analyzed. Quality of life of patients was also evaluated with the Oxford Knee Score (OKS). Results565 primary total knee replacements (TKR) were performed. A cut-off point was found in BMI of 30; 348 patients had a BMI ≤30 and 173 patients had a BMI >30. When comparing the two groups, a statistically significant difference (p = 0.0186) was found in the age at which the TKR was performed. There was a significant improvement for both groups in functional score (Oxford knee score). Additionally, intra and post-operative complications showed no statistically significant difference. Conclusionpatients with BMI greater than 30 required primary knee arthroplasty at a younger age (average: 3.5 years), compared to patients with a lower BMI. Obesity does not appear to confer and independent risk for surgery in the short and mid-term. Knee arthroplasty improves significantly quality of life in the short and mid-term, regardless of their BMI, as measured with the OKS.

Factors affecting aseptic loosening in primary total knee replacements: an in vitro study

BackgroundImplant surface integrity and cement bonding are assumed to be sufficient in primary total knee replacements to stabilize implants for extended wear without concerns over delamination and loosening. Yet there exists a significant rate of aseptic loosening where failure at implant cement interface occurs. The aim of this study is to look at specific aspects leading to aseptic loosening of the total knee replacement, where cement adhesion to the implant results in the lowest pull off strength.MethodsVirgin ceramic coated and uncoated chrome cobalt tibial trays were used in a pull off study using differing viscosities of cement at varied time intervals to compare which combination is strongest compared to which is least resistant to pull off testing.ResultsLow viscosity cement had a 44% (5.9 kg verses 3.3 kg, p < 0.001) higher pull-off strength compared to high viscosity cement. Coated implants had a 30% (3.9 kg verses 5.5 kg, p = 0.037) lower pull-off strength compared to non-coated. Testing measures were limited to cement utilization less than 5 minutes due to the poor adhesion of the dowels beyond this time. Finally, there was a significant difference in adhesion properties between brand names when utilizing low viscosity cement on the non-coated trays (10.34 kg for Simplex verses 4.87 for Palacos, p = 0.021).ConclusionThere are differences in adhesion properties between cement vendors, prompting significant concerns over the use of coated implants with particular cement types. Use of low viscosity cement on non-coated surfaces in the early liquid phase of cement curing was found to produce the best chance for adequate adhesion. This study demonstrates that there is variation in the adhesive properties of implants utilized in total knee replacements, and that the orthopedic community should consider not only the implant, cement, and curing time individually, but the overall integrity conferred from the combination of all of these variables.

Incidence of Mucoid Degeneration of Cruciate Ligaments in Patients Undergoing Primary Total Knee Replacements – A Study of 42 Knees

Mucoid degeneration of the ACL is largely an underdiagnosed condition. These are often misjudged as partial tears of ACL on routine MRI evaluation. Here we histologically analyse the incidence of mucoid degeneration of the cruciate ligaments in 32 patients who underwent primary total knee arthroplasty in our institute. 10 among them had bilateral total knee replacements making the total sample size 42 knees. ACL samples were sent for histopathological evaluation from 41 knees (one knee was an ACL deficient knee), and PCL samples were sent from patients who underwent total knee replacements with posterior stabilising implants. out of these 41 samples of ACL, 60.9 % turned out to be positive for mucoid degeneration. 9 out of 13 PCL samples (69.5%) turned out to be having mucoid degeneration. This study shows that the real incidence of mucoid degeneration of cruciate ligaments is much more than what is reported in literature. This emphasises the role of preoperative MRI to look for coexisting painful mucoid degeneration even in elderly patients with early osteoarthritis, which is an arthroscopically treatable condition thus delaying the total knee replacements in these patients. The higher incidence of mucoid degeneration in cruciate ligaments associated with advanced arthritis raises the question of functional integrity of PCL in these patients, making the use of posterior stabilising implants more advisable in patients with advanced stages of osteoarthritis.

Guided-motion hinged knee replacement prosthesis: early survival rate and postoperative patient function and satisfaction.

Literature on the survival rates and function of hinged total knee replacement (HTKR) prostheses is scarce, and to our knowledge there is not yet any published literature on the Legion HK Hinge Knee Replacement prosthesis (Smith & Nephew) with guided-motion articulation. The objective of this study was to establish the early survival rate of this modern HTKR at a single institution and to investigate postoperative patient function and satisfaction. This retrospective study included patients who received the Legion HTKR prosthesis with guided-motion inserts as a primary or revision implant between October 11 and March 2016 at a tertiary care centre in Manitoba, Canada. Preoperative and postoperative functional scores on the 12-item Oxford Knee Score and postoperative patient satisfaction were assessed. Thirty-nine HTKR implantations (38 patients) were included in this study: 12 primary cases and 27 revision cases. Three revision surgeries and 4 perioperative complications were noted at a mean follow-up of 29.1 months. The 2-year survivorship of the HTKR system was 90.7%. Postoperative functional scores improved significantly and the majority of patients were satisfied or very satisfied at all follow-up time points. The early survival rate of a modern guided-motion HTKR prosthesis is similar to the survival rates of other hinged knee prostheses published in the literature. The prosthesis demonstrated substantial postoperative functional improvement when used in the setting of complex primary or revision total knee replacement.

Tibial Tray with a Stem: Does It Have Any Role in Primary Cemented Total Knee Replacement?

Over many decades, total knee replacement (TKR) has become the ideal treatment option for advanced arthritis. Many designs were introduced to increase the stability of the tibial tray, hence the longevity of the prosthesis. This retrospective study was performed on 168 patients who received NexGen cemented primary total knee either with standard tibial tray (group A) or tibial tray with an intramedullary stem (group B) between May 2008 and May 2017. We reviewed all preoperative and postoperative clinical and radiological data retrospectively. In addition, a prospective clinical and radiological reassessment was done. Our aim was to answer the following questions: (1) Is there any difference between both groups in regard to clinical and radiological results? (2) Is there any difference in the revision rate? (3) Is there a role of using stemmed tibial tray in primary TKR? Better results were recorded in obese and severely obese patients having stemmed cemented tibial tray and so for patients with marked and severe preoperative varus angle. Our recommendations are to use cemented tibial tray with a stem in complicated primary surgery without fear of adverse effects on short and intermediate terms of follow-up.

Effect of Group-Based Outpatient Physical Therapy on Function After Total Knee Replacement: Results From a Multicenter Randomized Controlled Trial.

ObjectiveTo evaluate the long‐term clinical effectiveness of a novel group‐based outpatient physical therapy (PT) following total knee replacement (TKR).MethodsIn this 2‐center, unblinded, superiority, randomized controlled trial, 180 patients on a waiting list for primary TKR due to osteoarthritis were randomized to a 6 session group‐based outpatient PT intervention and usual care (n = 89) or usual care alone (n = 91). The primary outcome was patient‐reported functional ability measured by the Lower Extremity Functional Scale at 12 months postoperative. Secondary outcomes included knee symptoms, depression, anxiety, and satisfaction. Questionnaires were completed preoperatively and at 3, 6, and 12 months postoperatively.ResultsThe mean difference in function between groups was 4.47 (95% confidence interval [95% CI] 0.20, 8.75; P = 0.04) at 12 months postoperative, favoring the intervention. The mean difference in function between groups decreased over time, from 8.1 points at 3 months (95% CI 3.8, 12.4; P < 0.001) to 5.4 (95% CI 1.1, 9.8; P = 0.015) at 6 months postoperative. There were no clinically relevant differences in any secondary outcomes between groups, although patients in the intervention group were more likely to be satisfied with their PT. No serious adverse events related to the intervention were reported.ConclusionSupplementing usual care with this group‐based outpatient PT intervention led to improvements in function at 12 months after TKR, although the magnitude of the difference was below the minimum clinically important difference of 9 points. However, patient satisfaction was higher in the intervention group, and there was some evidence of clinically relevant improvements in function at 3 months.

Alternative Management Of Bone Defect In Primary Total Knee Replacement

Introduction:Bone defects are not common in primary total knee arthroplasty (TKA) contrary to a revision setting. The surgeon must assess the degree of complexity preoperatively and intraoperatively and have a broad armamentarium available during surgery. Multiple surgical options are available to repair or reconstruct the loss of bone, these include: bone cement, bone grafts, metal augments and custom-made implants. Principles to consider in bone loss management are knee and patient-related. Bone defects in primary TKA are usually associated malalignment of the limb combined with severe destruction of the articular cartilage. The treatment options for bone defects in primary TKA should be focus on preserving of the host bone, joint line restoration, balancing the flexion /extension stability and stabilizing the prosthesis.Materials/Methods:We are presenting a 65 years old lady with severe osteoarthritis bilateral varus deformity with severe bone loss over the posterior tibia condyle. Pre operatively multiple radiographs AP, lateral, patella skyline and oblique view are taken. For this patien we taken CT scan for assessment of the bone defect particularly on the tabia side. The pre operative templating of the radiographs is fundamental important in this patient in planning for primary complex TKA . This patient underwent bilateral total knee replacement with semiconstraint implant with mesh and impaction bone grafting over the posterior apesct of proximal tibia.Result:This patient was susseccfully operated with no immediate and post operative complication. Patient which unable to walk because of severe deformity able to gain confidence level to walk and back to her daily living activityDiscussion:Primary and revision TKA will continue to increase, proper management of femoral and tibia bone loss represents a common situation that have to be faced by the orthopaedic surgeon. Whatever technique is used in management of bone loss during knee arthroplasty, certain fundamentals must be applied and the remaining bone structure will guide treatment. For this case the bone defect was severe uncontained less than 50% of the posterior proximal was lost. Impaction grafting with mesh was performed to create back the proximal tibia. It’s give a new solid platform for the tibia tray to be inserted and this may allow the patient to weight bear immediately post operatively. This will avoid from using fully constrain implant which put more stress on the joint. Periarticular defect requiring more than a minimal prosthetic augment, it is imperative to use stemmed components to transfer stress away from join. Reestablishment of well-aligned and stable implants is necessary, but this can’t be accomplished without a sufficient restoration of an eventual bone lossConclusion:There are several treatment options to deal with a specific bone defect in the primary TKA and these options will be dictated by the patient’s factors, the defect factors and surgeon experience. Careful preoperative planning is essential to ensure successful reconstruction with all the appropriate armamentarium prepared.

Early Primary Total Knee Arthroplasty in Fractures Around The Knee – Malaysia District Hospital Experience

Introduction:Treatment of comminuted intra-articular fractures around the knee in the elderly population could be challenging. Factors such as pre-existing comorbidities, osteoporosis, cartilage damage and deformity could make fracture reduction difficult. Patients outcome is guarded due to risk of delayed or non-union, delayed weight bearing and prolonged rehabilitation phase.Methods:We present a retrospective study on 12 patients who underwent early primary total knee replacement after sustaining intra-articular fracture around the knee from 2017 to 2019. Legacy Constrained Condylar Knee (LCCK) were used and patients were follow-up at 3, 6 and 12 months.Results:Mean follow-up period is 14 months. All except one patient received Posterior Stabilized insert while other patients had LCCK. Two patients were complicated with prosthetic joint infection requiring debridement and revision surgery. The remaining patients achieved full knee extension and average flexion of 100 degrees.Conclusion:Early knee arthroplasty is able to achieve excellent short-term outcome in treatment of comminuted intra-articular fractures around the knee in elderly patients

Effects of Elastic Resistance Exercise After Total Knee Replacement on Muscle Mass and Physical Function in Elderly Women With Osteoarthritis: A Randomized Controlled Trial.

Knee osteoarthritis and age are associated with high sarcopenia risk, especially in patients who have received total knee replacement. The aim of this study was to identify the effects of elastic resistance exercise training after total knee replacement on muscle mass and physical outcomes in older women with knee osteoarthritis. Sixty older women who received unilateral primary total knee replacement surgery were randomized to an experimental group, which received 12 wks of postoperative elastic resistance exercise training, or a control group, which received standard care. The outcome measures included physical function performance (ie, Timed Up & Go, gait speed, forward reach, single-leg stance, timed chair rise), appendicular lean mass, and the Western Ontario and McMaster Universities Osteoarthritis Index. The assessment time points were 2 wks before surgery (T0), 1 mo after surgery (T1, before resistance exercise training), and 4 mos after surgery (T2, upon completion of resistance exercise training). After 12 wks of postoperative elastic resistance exercise training, the experimental group exhibited a significantly greater change in appendicular lean mass (mean difference = 0.81 kg, P = 0.004) than the control group. Elastic resistance exercise training also exerted significant effects on Timed Up & Go and gait speed with mean differences of 0.28 m/sec (P < 0.001) and -2.66 secs (P < 0.001), respectively. A 12-wk elastic resistance exercise training program after total knee replacement exerted benefits on muscle mass, mobility, and Western Ontario and McMaster Universities Osteoarthritis Index functional outcomes in older women with knee osteoarthritis.

Aspirin compared to enoxaparin or rivaroxaban for thromboprophylaxis following hip and knee replacement.

Background The risk of venous thromboembolism following major orthopaedic surgery is among the highest for all surgical specialties. Our hospital guidelines for thromboprophylaxis following elective primary total hip or knee replacement are based on American College of Chest Physicians guidance. The most recent change to local guidelines was the introduction of the extended aspirin regimen as standard thromboprophylaxis. Objective To establish the appropriateness of this regimen by comparing venous thromboembolism rates in patients receiving extended aspirin to previous regimens. Setting The largest dedicated orthopaedic hospital in Ireland. Methods This was a retrospective cohort study. Data were collected from patient record software. All eligible patients undergoing primary total hip or knee replacement between 1st January 2010 and 30th June 2016 were included. Main outcome measure Venous thromboembolism up to 6months post-operatively. Results Of the 6548 participants (55.3% female, mean age 65.4years (± 11.8years, 55.8% underwent total hip replacement), venous thromboembolism occurred in 65 (0.99%). Venous thromboembolism rate in both the inpatient enoxaparin group (n = 961) and extended aspirin group (n = 3460) was 1.04% and was 0.66% in the modified rivaroxaban group (n = 1212). Non-inferiority analysis showed the extended aspirin regimen to be equivalent to the modified rivaroxaban regimen. History of venous thromboembolism was the only significant demographic risk factor for post-operative venous thromboembolism (0.87% vs. 3.54%, p = 0.0002). Conclusion In daily clinical practice, extended aspirin regimen is at least as effective as modified rivaroxaban for preventing clinically important venous thromboembolism among patients undergoing hip or knee arthroplasty who are discharged from the hospital without complications. Aspirin can be considered a safe and effective agent in the prevention of venous thromboembolism after total hip or total knee replacement.

The metaphyseal sleeve: an unexplored option in the treatment of complex primary knee osteoarthritis

BackgroundIn an ever-aging society that as a whole has become more affluent, significant emphasis has been accorded to an improved quality of life. Knee osteoarthritis is ever-increasingly treated with total knee arthroplasty. The benefits and satisfaction experienced by those who have undergone total knee replacements (TKR) are well documented in the literature. The issue arises when osteoarthritis of the affected knee is more complex than simple osteoarthritis, i.e. the patient has complex primary osteoarthritis. This collective term encompasses conditions such as massive bone loss, ligamentous laxity, coronal defects and those with contractures. There are various classifications to describe massive bone loss but we utilized the Anderson Orthopaedic Research Institute (AORI) classification. Numerous treatment options are available and we report the use of metaphyseal sleeves as a highly successful treatment option.MethodsWe retrospectively reviewed all the patients at our centre who underwent primary TKR using the metaphyseal sleeves. Patients were assessed on symptoms and functional status, and radiographs were also taken to assess for osseointegration. Only patients who completed 2 years of follow up were included in our study.ResultsThe updated (2011) Knee Society Score (KSS) was used in conjunction with radiological assessments at each follow up. Mean KSS scores improved from 53.83 preoperatively to 193.39 postoperatively. All patients demonstrated increasing osseointegration throughout follow up.ConclusionThe metaphyseal sleeve is an excellent treatment option for complex primary osteoarthritic knees with good results objectively, functionally and radiologically and would be a great choice for all orthopaedic surgeons to include in their armamentarium.

Peri-Prosthetic Joint Infection of the Knee Causes High Levels of Psychosocial Distress: A Prospective Cohort Study.

Background: Peri-prosthetic joint infection (PJI) is a major complication of knee arthroplasty that can cause long-term disability. In addition to its physical impact, there is a clear psychological burden that has not been measured yet. We hypothesized that the psychosocial burden of PJI can be assessed quantitatively using standardized questionnaires and may be correlated with treatment stage. Methods: Thirty-one patients were enrolled in this longitudinal prospective cohort study from August 2015 to November 2016. Participants had clinically established knee PJI after primary total knee replacement in osteoarthritis according to the Musculoskeletal Infection Society criteria and underwent a standardized two-stage protocol. After explantation of the prosthesis and implantation of a polymethylmethacrylate knee spacer, patients were treated with organism-specific intravenous antibiotics for two weeks, followed by oral antibiotics for four weeks; and then reimplantation was performed in all cases. Psychometrically validated standardized questionnaires were used to measure psychosocial stress via self-assessment at four time points: (1) Before explantation of the prosthesis; (2) after explantation; (3) after the antibiotic treatment before reimplantation; and (4) three months after reimplantation (follow-up). The Patient Health Questionnaire (PHQ)-4, Short Form (SF)-12 (including PSK and KSK), Questions about Life Satisfaction (FLZM) and Fear of Progression (PA-F-KF) (titles and abbreviations in German) scores were interpreted according to cut-off values for depression, fear of progression, anxiety, and quality of life. Results: Eighteen patients (58.1%) showed a PHQ-4 score above the cut-off value for depression at least once, with the highest score before reimplantation (time point 3). On the SF-12, the mean subtest mental scale (PSK) score was 42.6 (± 14.5), and the mean subtest physical scale (KSK) score was 26.9 (± 7.5) over the four time points, which was significantly lower than that of the general German population (PSK 53.1, KSK 44.0; p < 0.05). The SF-12 scores did not change significantly over time. On the FLZ, health was least satisfactory, followed by recreational activities and work. On the PA-F-KF, patients had the greatest fear of being dependent on outside help, drastic medical interventions, and infection progression. The mean PA-F-KF value was 31.24 (± 9.60; values ≥34 are regarded as critical). Conclusion: Peri-prosthetic joint infection is a measurable, relevant psychosocial stressor for patients. Their quality of life and fear of the disease progressing are comparable to those of oncology patients. Routine screening should be conducted to identify affected patients early for appropriate treatment, improving long-term outcomes. Orthopaedic surgeons who treat patients with PJI should initiate by psychologists as well in order to maintain the patient's long-term quality of life.

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.

Topical tranexamic acid in cemented primary total knee arthroplasty without tourniquet: a prospective randomized study.

Tranexamic acid (TXA) has been shown to be effective in reducing blood loss after total knee replacement. The purpose of this study was to prospectively assess the effectiveness of topical TXA use, to reduce blood loss after primary total knee replacement without tourniquet, and to compare these outcomes with a control group that did not receive tranexamic acid. This is a prospective, randomized study to assess the effect of a 2-g topical tranexamic acid in 50mL physiological saline solution in total knee replacement without tourniquet and drain. Primary outcomes were total blood loss. Secondary outcomes were hemoglobin and hematocrit level, hemoglobin and hematocrit drop, transfusion rates, length of hospital stay, deep vein thrombosis, and pulmonary embolism events. Preoperative and intraoperative data were similar between the two groups. The mean total blood loss was 620mL in the topical tranexamic acid group and 1094mL in the control group with significant differences (p = 0.001), which meant 43% reduction in total blood loss. The hemoglobin and hematocrit postoperative value was significantly higher in the topical tranexamic acid group than in the control group (p = 0.002). Transfusion rates were 0% in the topical tranexamic group and 4.3% in the control group. The length of stay was significantly lower in the topical tranexamic acid group (p = 0.01). There were no DVT or PE in any group. A single dose of 2-g TXA in 50mL topical administration significantly reduces blood loss and improves postoperative blood chemistries in patients undergoing unilateral primary cemented TKA without tourniquet and drain compared to a control group, without increasing the risk of thromboembolic complications.

Can Body Height Be Used to Predict Knee Implant Sizes?

Introduction: Accuracy of pre-operative templating using radiographs or joint replacement programmes is variable. Implant modularity has increased the number of sizes available and trays used per procedure. Multiple intra-operative implant size trials lead to longer surgery time and greater instrument maintenance costs. It was hypothesised that patient factors could predict the size of implant and tray required, thereby increasing efficiency and reducing operative time. This study aims to identify correlation between implant size and body height to improve efficiency and reduce costs. Method: This prospective cohort study includes patients who underwent primary total knee replacement using the DePuy ATTUNE® Primary Total Knee System between 1st January 2016 to 7th August 2017 performed by a single surgeon, at a single hospital. Post-operative x-rays were reviewed for appropriate implant sizing. The DePuy ATTUNE® Primary Total Knee System has five sets, split into sizes 1-2, 3-5, 6-8 and 9-10. Results: 188 patients (205 knees) were included, 66 male and 122 female. Male height was 174.6cm (152-194.3) with average implant size 8. Female height was 158.7cm (145-177.8) with average implant size 5. The Spearman rank correlation between body height, femoral and tibial size were 0.793 and 0.837 respectively. All men &lt;170cm and &gt;185cm used the 6-8 and 9-10 set respectively. All women &lt;150cm and &gt;170cm used the 3-5 and 6-8 set respectively. Conclusion: The positive correlation identified coincides with existing literature. Using extremes of height and gender, surgeons and theatre staff could predict the likely trial set required, improve theatre efficiency and reduce costs.

Osteoarthritis Preoperative Package for care of Orthotics, Rehabilitation, Topical and oral agent Usage and Nutrition to Improve ouTcomes at a Year (OPPORTUNITY); a feasibility study protocol for a randomised controlled trial

BackgroundPatients’ pre-operative health and physical function is known to influence their post-operative outcomes. In patients with knee osteoarthritis, pharmacological and non-pharmacological options are often not optimised prior to joint replacement. This results in some patients undergoing surgery when they are not as fit as they could be. The aim of this study is to assess the feasibility and acceptability of a pre-operative package of non-operative care versus standard care prior to joint replacement.Methods/designThis is a multicentre, randomised controlled feasibility trial of patients undergoing primary total knee replacement for osteoarthritis. Sixty patients will be recruited and randomised (2:1) to intervention or standard care arms. Data will be collected at baseline (before the start of the intervention), around the end of the intervention period and a minimum of 90 days after the planned date of surgery. Adherence will be reviewed each week during the intervention period (by telephone or in person). Participants will be randomised to a pre-operative package of non-operative care or standard care. The non-operative care will consist of (1) a weight-loss programme, (2) a set of exercises, (3) provision of advice on analgesia use and (4) provision of insoles. The intervention will be started as soon as possible after patients have been added to the waiting list for joint replacement surgery to take advantage of the incentive for behavioural change that this will create. The primary outcomes of this study are feasibility outcomes which will indicate whether the intervention and study protocol is feasible and acceptable and whether a full-scale effectiveness trial is warranted.The following will be measured and used to inform study feasibility: rate of recruitment, rate of retention at 90-day follow-up review after planned surgery date, and adherence to the intervention estimated through review questionnaires and weight change (for those receiving the weight-loss aspect of intervention). In addition the following information will be assessed qualitatively: analysis of qualitative interviews exploring acceptability, feasibility, adherence and possible barriers to implementing the intervention, and acceptability of the different outcome measures.DiscussionThe aims of the study specifically relate to testing the feasibility and acceptability of the proposed effectiveness trial intervention and the feasibility of the trial methods.This study forms the important first step in developing and assessing whether the intervention has the potential to be assessed in a future fully powered effectiveness trial. The findings will also be used to refine the design of the effectiveness trial.Trial registrationISRCTN registry, ID: ISRCTN96684272. Registered on 18 April 2018.

Early Clinical and Functional Outcome of Primary Total Knee Replacement with Posterior Cruciate Substituting Prosthesis for Primary Knee Osteoarthritis Using 2011 Knee Society Score

Background: Primary knee Osteoarthritis (OA) is the commonest articular disease in middle age and elderly people. Primary total knee replacement (TKR) is a known world-wide standard and definitive treatment of primary knee OA following failed adequate non-operative management. It is of clinical importance to assess the clinical and functional outcome of TKR to prognosticate the severity of primary knee OA. The new (2011) knee society scoring system (nKSS) is both surgeons and patients’ assessment tool for the treatment outcome of TKR. Study Design: Prospective interventional analytical study. Aim and Objective: The aim of the study was to determine early clinical and functional outcome of primary total knee replacement in patients with primary knee osteoarthritis using nKSS. The objectives were: 1) To determine the pre-operative nKSS and post operative nKSS; 2) To determine relationships between pre-operative nKSS and post operative nKSS at 6 weeks, 3, 6, 9 and 12 months; 3) To determine the complication rates in patients undergoing primary TKR in the study centre. Methods: A prospective interventional study of 59 patients aged 51 to 70 years who had 67 Total Knee Replacements (TKRs) participated in the study between November 2015 to June 2018 at National Orthopaedics Hospital, Lagos, Nigeria. Patients’ sociodemographic data, pre-operative and post-operative nKSS system were recorded at 6 weeks, 3, 6, 9 and 12 months during follow up. The data were analyzed using Statistical Package for Social Science (SPSS). Results: There were 41 females and 18 males (M:F = 1:2.3). There were total of 67 TKRs with 31 right TKRs, 20 left TKRs and 8 staged bilateral TKRs. The participants’ age ranged from 51 to 70 years with the mean age of 59.5 (±8.5) years. Four patients did not complete the study due to various reasons. The remaining 55 participants completed the study period with progressive improvement of their post-operative nKSS at 6 weeks, 3, 6, 9 and 12 months post-operatively when compared with pre-operative nKSS (P value 0.5). Conclusion: This study revealed improved early clinical and functional outcome of primary total knee replacement in primary knee osteoarthritis using nKSS in all the studied patients. There is no significant negative effect of lower pre-operative nKSS (and its components) on the post-operative nKSS outcome.

Relevance of Asymmetric Extension Gap on Initial Post-Operative and Weight-Bearing X-Rays After Total Knee Replacement

Introduction Asymmetric gap between the femoral and tibial component after primary total knee replacement (TKR) is a known cause of post-operative pain. This study investigates whether significant asymmetric extension gaps seen on initial post-operative non-weight-bearing (NWB) radiographs persist on follow-up weight-bearing (WB) radiographs. Method 203 consecutive patients who underwent primary TKR, and had adequate radiographic follow-up during a four-year period, were included. The distance between the tibial tray and femoral condyle on the medial and lateral sides was measured on initial NWB and follow-up WB radiographs, to identify significant asymmetric extension gaps. Previous studies showed medial extension gaps of ≥1.5mm may be associated with increased pain post-operatively. Therefore, we defined a significant gap as ≥1.5mm. The results were examined to determine whether initial post-operative gaps remain appreciable on follow-up x-rays. Results Of the 203 radiographs reviewed, 29 (14.3%) patients had an extension gap mismatch of ≥1.5mm on initial post-operative imaging. 13 (44.8%) patients had a medial opening gap whilst 16 (55.2%) had a lateral opening. Only 4 (13.8%) of these patients showed no significant change in the asymmetrical extension gap (remained ≥1.5mm) on WB x-rays. In the remaining patients, the gap was no longer appreciable. Conclusion The study showed that if patients present with post-TKR pain, which could be related to a medial opening extension gap, clinicians should use initial NWB x-rays to investigate as the gap mismatch may not be detectable on follow-up WB radiographs.

Economic Burden of Periprosthetic Joint Infection Following Primary Total Knee Replacement in a Developing Country.

BackgroundPeriprosthetic joint infection is one of the devastating complications after primary total knee arthroplasty, which increases the financial burden on patients and affects their quality of life as well. The financial burden of periprosthetic joint infection after joint replacement in developed countries is well known. There is a need to evaluate the economic burden in developing countries such as Pakistan.MethodsThis is a single-center, retrospective, case-control study conducted at the Department of Orthopedic Surgery, Liaquat National Hospital Karachi. Cases of primary total knee arthroplasty performed during this study were divided into 2 groups: uneventful primary total knee arthroplasty and periprosthetic joint infection treated with 2-stage revision. To calculate the final cost, we divided the total hospital cost into the hospital stay cost and operating room cost.ResultsDuring study period, 32 patients were diagnosed with periprosthetic joint infection. The total cost of revision surgery for periprosthetic joint infection considering 2 hospitalizations was 1,780,222 ± 313,686 Pakistani rupee (PKR). The total cost of uneventful arthroplasty was 390,172 ± 51,460 PKR. We observed significant difference with respect to economic details between the 2 groups.ConclusionsManagement of periprosthetic joint infection was 4.5 times more expensive than uneventful primary total knee arthroplasty. Measures should be undertaken to reduce the prevalence of periprosthetic joint infection, thereby reducing patients' economic burden.

Retrospective Analysis of Pain Relief in Total Knee Replacement Surgeries.

Background and Aims:The aim of the study is to measure the postoperative adequacy of pain relief and functional recovery after unilateral primary total knee arthroplasty or total knee replacement (TKR) with a multimodal approach.Settings and Design:This was a retrospective observational study done in a tertiary care center.Materials and Methods:Eighty patients aged 18–65 years (yrs) with ASA Physical Status Classes I, II, and III operated for unilateral primary TKR surgery under suitable Anaesthesia and was administered ultrasound-guided adductor canal block + periarticular infiltration (PI) from January 2018 to January 2019 were included. Thereafter, the patients visual analog scale (VAS) scores at rest, 45° knee flexion, and mobilization as well as additional analgesia given were noted after going through the records at following time points: 12 hourly for 24 h and thereafter on postoperative day 1 (POD1) and POD2. Level of block, adverse events, and functional recovery (time up and go [TUG] test, 10 s walk test) on POD1 and POD2 were also noted.Statistical Analysis and Results:The statistical software namely SPSS 18.0 were used for the analysis of the data. The mean VAS score at 12 h was 4.33 ± 1.3 which worsened at 24 h with steady improvement over the next 2 days. Similarly, the case with a mean VAS score at 45° flexion and on mobilization showed a similar trend. At 12 h postadductor block, besides intravenous (i.v.) paracetamol, 32.6% of patients were given tramadol 50 mg i.v. whereas one patient was given a buprenorphine patch in addition to tramadol. The number of patients requiring additional tramadol and buprenorphine patch steadily increased over the next 2 days. The average time taken for the TUG test at 24 h was 30.98 ± 4.77 s, and the average time taken for the 10 s walk test at 24 h was 6.16 ± 1.10 steps with improvement in performance over the next 2 days.Conclusion:In our study, our multimodal analgesia model did not provide satisfactory analgesia though mobilization was not hampered.