Academic literature on the topic 'Total knee replacement Complications Risk assessment Statistical methods'

Background Although routine NHS data potentially include all patients, confounding limits their use for causal inference. Methods to minimise confounding in observational studies of implantable devices are required to enable the evaluation of patients with severe systemic morbidity who are excluded from many randomised controlled trials. Objectives Stage 1 – replicate the Total or Partial Knee Arthroplasty Trial (TOPKAT), a surgical randomised controlled trial comparing unicompartmental knee replacement with total knee replacement using propensity score and instrumental variable methods. Stage 2 – compare the risk benefits and cost-effectiveness of unicompartmental knee replacement with total knee replacement surgery in patients with severe systemic morbidity who would have been ineligible for TOPKAT using the validated methods from stage 1. Design This was a cohort study. Setting Data were obtained from the National Joint Registry database and linked to hospital inpatient (Hospital Episode Statistics) and patient-reported outcome data. Participants Stage 1 – people undergoing unicompartmental knee replacement surgery or total knee replacement surgery who met the TOPKAT eligibility criteria. Stage 2 – participants with an American Society of Anesthesiologists grade of ≥ 3. Intervention The patients were exposed to either unicompartmental knee replacement surgery or total knee replacement surgery. Main outcome measures The primary outcome measure was the postoperative Oxford Knee Score. The secondary outcome measures were 90-day postoperative complications (venous thromboembolism, myocardial infarction and prosthetic joint infection) and 5-year revision risk and mortality. The main outcome measures for the health economic analysis were health-related quality of life (EuroQol-5 Dimensions) and NHS hospital costs. Results In stage 1, propensity score stratification and inverse probability weighting replicated the results of TOPKAT. Propensity score adjustment, propensity score matching and instrumental variables did not. Stage 2 included 2256 unicompartmental knee replacement patients and 57,682 total knee replacement patients who had severe comorbidities, of whom 145 and 23,344 had linked Oxford Knee Scores, respectively. A statistically significant but clinically irrelevant difference favouring unicompartmental knee replacement was observed, with a mean postoperative Oxford Knee Score difference of < 2 points using propensity score stratification; no significant difference was observed using inverse probability weighting. Unicompartmental knee replacement more than halved the risk of venous thromboembolism [relative risk 0.33 (95% confidence interval 0.15 to 0.74) using propensity score stratification; relative risk 0.39 (95% confidence interval 0.16 to 0.96) using inverse probability weighting]. Unicompartmental knee replacement was not associated with myocardial infarction or prosthetic joint infection using either method. In the long term, unicompartmental knee replacement had double the revision risk of total knee replacement [hazard ratio 2.70 (95% confidence interval 2.15 to 3.38) using propensity score stratification; hazard ratio 2.60 (95% confidence interval 1.94 to 3.47) using inverse probability weighting], but half of the mortality [hazard ratio 0.52 (95% confidence interval 0.36 to 0.74) using propensity score stratification; insignificant effect using inverse probability weighting]. Unicompartmental knee replacement had lower costs and higher quality-adjusted life-year gains than total knee replacement for stage 2 participants. Limitations Although some propensity score methods successfully replicated TOPKAT, unresolved confounding may have affected stage 2. Missing Oxford Knee Scores may have led to information bias. Conclusions Propensity score stratification and inverse probability weighting successfully replicated TOPKAT, implying that some (but not all) propensity score methods can be used to evaluate surgical innovations and implantable medical devices using routine NHS data. Unicompartmental knee replacement was safer and more cost-effective than total knee replacement for patients with severe comorbidity and should be considered the first option for suitable patients. Future work Further research is required to understand the performance of propensity score methods for evaluating surgical innovations and implantable devices. Trial registration This trial is registered as EUPAS17435. Funding This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 66. See the NIHR Journals Library website for further project information.

Background: The objective of this study was to look for the outcome of TKR in obese individuals. Methods: The data of all patients who had undergone primary TKR between 2005 and 2015 were collected from the QuadruMed Patient Care System and crosschecked with the operating room. The biometric data of age, gender, weight and postoperative follow up, any complications were collected from the medical charts. Patients were classified as per the BMI (Body Mass Index). BMI is classified as per the WHO classification of 2000 Results Two hundred and four patients fulfilled the criteria for inclusion. The demographic data is given in Table 2. The average age 59.8±9.3 years. Right side was operated in 103 and left in 101 patients. The average BMI was 35.88±7.47 (Range 21.95-54.78); mean duration of surgery was 163.37±29.9 (Range 88-250) minutes. The range of follow up was 5-14 years with the average of 7.49±2.56 years. There were 18 (8.8%) complications. One hundred and three (50.5%) of the patients belonged to Class II Obesity (BMI ≥36Kg/M2). Between class II obesity and Class III obesity (BMI ≥41Kg/M2, the later had 94.4% of the complications. The level of satisfaction was similar in all the groups at 80%. High BMI and longer duration of surgery were important and statistically significant risk factors (p <0.0001 and <0.009) for complications during TKA. Post operative data on VAS, Modified Knee Scoring Score and WOMAC grading, showing low scores of all the assessment in the patients with higher BMI. Conclusions: Our analysis shows that our patients with Class III obesity had over 90% of the complications and we believe that patients in this BMI range should seek ways to reduce their body weight to avoid complications and long-term morbidity.

<p><strong>Background: </strong>The choice between preserving, sacrificing or substituting the posterior cruciate ligament (PCL) is always a controversial topic in total knee replacement (TKR). Dished polyethylene insert with PCL resection enables correction of the commonly present fixed flexion and varus deformities. Additionally, the risk of premature wear of polyethylene is less because of the confirming articular geometry between the femoral and tibial component.<strong></strong></p><p><strong>Methods: </strong>This is a retrospective study in which we studied 120 knees in 95 consecutive patients undergoing primary TKR by the senior author at our institute. We used TKR system with dished metal backed polyethylene tibial component. PCL resection was performed in all cases. Pre-operative and post-operative functional assessment were done using knee society clinical scores and Western Ontario and McMaster universities osteoarthritis index (WOMAC). All radiographs were assessed using the knee society Roentgenographic scoring system (KSRES). Statistical analysis was performed using paired student t tests. Survivorship was determined using Kaplan-Meier survivorship curves. <strong></strong></p><p><strong>Results: </strong>Mean follow-up was 8 years. Range of motion increased from 75 degrees to 110 degrees. The knee society pain score increased from 30 to 94. The knee society function score increased from 35 to 75. WOMAC score increased in terms of pain, stiffness and physical function.<strong></strong></p><p><strong>Conclusions: </strong>We conclude that deep dish bearing is a viable option in presence of deficient PCL and provides adequate stability and functional outcome. We need a larger sample size, multicentre trial and longer follow-up to see for complication rate, revision rate and survival.</p>

<p class="abstract"><strong>Background:</strong> The present study was carried out with the objective to assess the influence of morbid obesity on the outcome after TKR and with the aim to compare the outcome following TKR in a consecutive series of morbidly obese patients (BMI &gt;40 kg/m²), and matched it with group of non-obese patients (BMI &lt;30 kg/m²).</p><p class="abstract"><strong>Methods:</strong> The study period planned was of two years. The totals of 100 patients undergoing total knee replacement were selected for the study period. On the basis of body mass index inclusion criteria for the two groups were decided. Of the total 100 patients, they were divided into two groups. One group 1 consisted of obese patients with total of 50 patients and group 2 consisted of non-obese patient with total of 50 patients.<strong></strong></p><p class="abstract"><strong>Results:</strong> At the end of two years when the data was compared with the preoperative assessment, it was found to significantly better where value of p was &lt;0.001. However when the comparison was done between the two groups, it was found that scores were lower in the group 1 patients which included the obese patients.</p><p><strong>Conclusions:</strong> Total knee arthroplasty is a safe and efficacious operation in obese patients with no significantly greater risk of complications. However, post-operative clinical scores and absolute improvement in the scores are statistically superior in non-obese patients at one year follow-up. Obese patients should be started on weight loss programs and counselled about possible inferior results for total knee replacement. </p>

Background: Vascular thromboembolism is one of the major concerns of orthopedic surgeons after hip or knee replacement surgery. Although many thromboprophylactic drugs have been introduced, there is still no consensus over their efficacy and safety. Therefore, this study aimed to compare the efficacy and safety of oral rivaroxaban and aspirin administration and enoxaparin injections in patients undergoing knee or hip replacement. Objectives: Determination and comparison of the side effect and efficacy of Rivaroxaban and Enoxaparin after total hip or knee arthroplasty. Methods: A total of 231 patients undergoing knee or hip replacement surgery were included in the study. Of them, 31 patients were excluded due to missing the follow-up. Of the remaining 200 patients, 42 low-risk and 158 moderate- to high-risk patients were identified, according to Caprini risk assessment model. Then, they were divided into three groups: aspirin (42 patients), enoxaparin (78 patients), and rivaroxaban (80 patients). Severe hemorrhage (hemoglobin reduction of more than 2 g/dL or requiring blood transfusion) was assessed after the first dose of medication until discharge through daily hemoglobin testing. Frequency of other side effects such as wound complications (ecchymosis, hematoma, and wound infection) and gastrointestinal or skin problems was recorded and compared by daily examination during the hospital stay and then in the future visits to the clinic up to 6 months in each group. Follow up visits were performed at weeks 6, 12, and 24. Results: No cases of deep vein thrombosis or pulmonary thromboembolism were observed in any of the study groups. There was no significant difference between the two groups in the number of major bleeding cases (P=0.39). Ecchymosis around the wound was significantly higher in the rivaroxaban group than in the enoxaparin group (33.8% vs. 23%). However, this difference was not statistically significant (P=0.06). Conclusion: The efficacy and safety of rivaroxaban and enoxaparin drugs are comparable. Although ecchymosis was seen after using rivaroxaban rather than enoxaparin, rivaroxaban is orally administered and costs less for the patient and the health system. So, its use as a thromboprophylactic drug of choice following hip and knee arthroplasty surgery is still recommended.

Background: Neuropathic knee pain, particularly of the infrapatellar branch, is an important complication of knee replacement surgery, with an incidence as high as 70%. The increasing number of elderly patients requiring knee surgery, including total knee arthroplasty (TKA), has contributed to an increase in the number of patients with this pathology. Treatment includes neurectomy, infiltration therapy, and cryodenervation. Percutaneous cryodenervation of the infrapatellar branch is a promising option. Objective: To provide the necessary anatomical analysis to optimize percutaneous cryodenervation of the infrapatellar branch by defining sections of the unbranched ramus infrapatellaris to demonstrate the risk of nerve injury through 3 different skin incisions typically used during TKA. Study Design: Anatomical study. Methods: Cadavers were used for assessment. Exclusion criteria were scars from knee surgery, deep wounds, and a flexion angle of no more than 90°. We compared 3 frequently used skin incisions with the course of the infrapatellar branch and identified sections of the unbranched nerves that were suitable for percutaneous cryodenervation. Results: In total, 18 formalin-fixed cadavers (mean age, 78.9 years) contributed 30 knees (15 pairs) for dissection. We identified the following 4 anatomical variations of the ramus infrapatellaris in relation to the sartorius muscle: anterior, posterior, penetrating, and pes anserinus types. Sections were then found to treat the nerve branch types. The nerve sections were localized using the medial pole of the patella as a palpable landmark and varied in length between 15 mm and 40 mm. The medial parapatellar skin incision showed the highest risk of lesions to the infrapatellar branch (53.3%) followed by the midline skin incision (46.7%) and the lateral parapatellar skin incision (30.0%). Limitations: This was an observational study, performed using a limited number of cadavers. This therefore precluded generalization and statistical analysis. Significantly more female (13) cadavers were examined compared to male (5). Further studies in human populations, and with larger samples, are necessary to confirm these results. Conclusion: Based on our findings, the surgeon can localize the unbranched main nerve. Compared with the current practice, our approach should allow for a lower impact on tissues and should facilitate complete pain relief through a single cryodenervation. Furthermore, we propose that the lateral parapatellar skin incision is an acceptable alternative surgical approach in knee replacement surgery because it is associated with the lowest risk of damage to the infrapatellar branch. Key words: Percutaneous cryodenervation, infrapatellar branch, neuropathic knee pain, knee surgery, skin incisions knee surgery, total knee arthroplasty

Abstract Abstract 169 Introduction: Venous thromboembolism (VTE) is a common complication after hip or knee replacement and is associated with significant morbidity and mortality. Anticoagulants reduce the risk of these complications, but can also result in increased bleeding, thus requiring an assessment of benefit–risk. Patients and Methods: To obtain more precise estimates of treatment effects on low frequency events, data were pooled from 4 phase 3 randomized clinical trials (RECORD1–4) of rivaroxaban vs enoxaparin regimens (or enoxaparin/placebo combination in 1 study) for the prevention of deep vein thrombosis (DVT) and pulmonary embolism (PE) in total hip and knee replacement. Although the studies were designed to answer slightly different questions and differed in treatment duration and comparator dose, pooling was supported by similar study designs, identical endpoints, identical event ascertainment methods, and the same independent central blinded adjudication committees. Benefit–risk was assessed by comparing the excess number of outcome events for benefits vs that for harms (‘risks'), occurring over the treatment period. Excess number of events was defined as the number of events in a hypothetical population of 10,000 patients treated with enoxaparin minus the number of events in such a population treated with rivaroxaban. A positive value indicates that fewer events occur in the population treated with rivaroxaban. The analysis was undertaken for several clinically comparable pairs of composite benefit and harm outcomes: total VTE (any DVT, non-fatal PE, or death from any cause) vs major and clinically relevant non-major (CRNM) bleeding; major VTE (proximal DVT, non-fatal PE, or VTE-related death) vs major bleeding; and symptomatic VTE/all-cause mortality vs major bleeding. For each pair, pooled Mantel–Haenszel weighted risk differences were used to compute the excess number of benefit and harm events, and the difference between excess numbers of events was used to evaluate net clinical benefit (NCB; Table). In all calculations, benefits and risks were weighted equally. An additional assessment was performed using all treatment-emergent serious adverse events (SAEs) as reported by investigators. Results: Rixaroxaban is associated with statistically significantly fewer total VTE, major VTE, and symptomatic VTE/all-cause mortality events than enoxaparin, whereas enoxaparin is associated with a smaller number of different bleeding events, although no bleeding endpoints, other than the composite of major + CRNM bleeding, were statistically significantly different. In each pairwise comparison, the excess number of bleeding events is less than the excess number of VTE-related events by a factor ranging from 4 to 10 (Table). Enoxaparin was also associated with an excess of 194 treatment-emergent SAEs compared with rivaroxaban out of 10,000 patients. In all cases, there is a positive NCB for rivaroxaban vs enoxaparin with 95% confidence intervals (CIs) excluding 0, suggesting that the benefits of rivaroxaban exceed the risks when compared with enoxaparin. Conclusions: This quantitative benefit–risk approach provides a comparison of interventions in clinically relevant population terms. Using the net clinical benefit approach, for a variety of endpoints defining benefits and harms, the benefit–risk profile for rivaroxaban is consistently improved compared with enoxaparin for patients after elective hip and knee replacement. Disclosures: Levitan: Johnson & Johnson Pharmaceutical Research & Development, L.L.C.: Employment, Equity Ownership. Yuan:Johnson & Johnson Pharmaceutical Research & Development, L.L.C.: Employment, Equity Ownership. Turpie:Johnson & Johnson Pharmaceutical Research & Development, L.L.C.: Consultancy; Bayer Schering Pharma AG: Consultancy, Speakers Bureau; sanofi-aventis: Consultancy; GSK: Consultancy; Astellas: Consultancy; Takeda: Consultancy; Portola: Consultancy. Friedman:Boehringer Ingelheim : Consultancy, Research Funding; Johnson & Johnson : Consultancy; Astellas US: Consultancy, Research Funding; Sanofi-Aventis: Consultancy. Homering:Bayer Schering Pharma AG: Employment. Berlin:Johnson & Johnson Pharmaceutical Research & Development, L.L.C.: Employment, Equity Ownership. Berkowitz:Bayer HealthCare Pharmaceuticals: Employment. DiBattiste:Johnson & Johnson Pharmaceutical Research & Development, L.L.C.: Employment.

Chronic postoperative pain (POP) is a serious complication of total replacement (TR) of the knee (KJ) and hip (HJ) joints.Objective: to determine the factors associated with POP in patients after TR of KJ or HJ.Patients and methods. The study group consisted of 124 patients with knee osteoarthritis or hip osteoarthritis (age 63.6±9.9 years, 63% women and 37% men) who underwent TR of KJ or HJ. POP was defined as pain ≥40 mm on a numerical rating scale persistent for ≥3 months. Its presence was assessed after 3 and 6 months by telephone survey. Comparison of patients with POP and without it was carried out for a number of factors identified before surgery.Results and discussion. The incidence of POP was 27.4%. There was no difference in the incidence of POP in patients after TR of KJ or HJ: 28.1% and 26.9% (p=0.88). POP was statistically significantly associated with parameters such as higher body mass index (BMI); the intensity of pain at rest; general assessment of impairment; WOMAC index pain, stiffness and overall; severity of symptoms of neuropathic pain (PainDETECT); signs of depression and anxiety (HADS).The risk of POP was significantly higher (p<0.05) with BMI >30 kg/m2 (odds ratio, OR 2.755; 95% confidence interval, CI 1.053–7.206), rest pain ≥40 mm on a visual analog scale (OR 1.349; 95% CI 0.478–3.803), PainDETECT scores ≥13 (OR 3.598; 95% CI 1.048–12.36) and HADS depression ≥8 (OR 2.193; 95% CI 0.745–6.454), presence of ≥2 sources of pain (OR 6.996; 95% CI 2.358–20.756).Conclusion. It was found that the risk of POP after TR of KJ and HJ is higher in patients with overweight, severe preoperative pain, signs of neuropathic pain and depression, as well as in the presence of several sources of pain (except for the affected joint, that was replaced surgically).

Introduction. Total hip replacement is an operative treatment method for end-stage osteoarthritis, considered the most effective nowadays. One of the typical complications after the procedure is heterotopic ossification which may influence patient posture stability and increase the risk of falls. Aim. The study aimed to assess whether patients developing heterotopic ossifications after total hip replacement have a higher risk of falls in comparison to the matched-cohort group without them. Materials and methods. 46 out of 312 patients undergoing a total hip replacement in 2020 who developed heterotopic ossifications were observed. For these patients, a propensity score based on age, sex, and BMI was generated, and a matched-cohort control group consisting of 39 patients was selected. Each patient was operated on via an anterolateral approach, and an uncemented total hip prosthesis was implanted. Patients from both cohorts underwent postoperative radiological and biomechanical assessment and fulfilled WOMA C and Oxford questionnaires pre-and postoperatively. Statistical analyses of the results were performed. Results. There were statistically significant differences between cohorts in the postural stability test (4.9±1.1 vs 2.0±1.0 p<0.05), antero-posterior stability index (3.6±1.2 vs 1.6±0.9, p<0.05), medio-lateral stability index (3.0±1.3 vs 1.0±0.7, p<0.05) and risk of fall test (9.8±1.0 vs 7.8±1.0, p<0.05). No statistically significant differences were observed in the WOMA C and Oxford questionnaires. Conclusions. Our study proved that heterotopic ossifications, which appear in hip abductor muscles, could have an impact on balance and the risk of falls in patients after total hip replacement. In the elderly population, this can result in serious consequences such as a periprosthetic fracture or head trauma after total hip replacement.

Aims Recent improvements in surgical technique and perioperative blood management after total joint replacement (TJR) have decreased rates of transfusion. However, as many surgeons transition to outpatient TJR, obtaining routine postoperative blood tests becomes more challenging. Therefore, we sought to determine if a preoperative outpatient assessment tool that stratifies patients based on numerous medical comorbidities could predict who required postoperative haemoglobin (Hb) measurement. Methods We performed a prospective study of consecutive unilateral primary total knee arthroplasties (TKAs) and total hip arthroplasties (THAs) performed at a single institution. Prospectively collected data included preoperative and postoperative Hb levels, need for blood transfusion, length of hospital stay, and Outpatient Arthroplasty Risk Assessment (OARA) score. Results A total of 504 patients met inclusion criteria. Mean age at time of arthroplasty was 65.3 years (SD 10.2). Of the patients, 216 (42.9%) were THAs and 288 (57.1%) were TKAs. Six patients required a blood transfusion postoperatively (1.19%). Transfusion after surgery was associated with lower postoperative day 1 Hb (median of 8.5 (interquartile range (IQR) 7.9 to 8.6) vs 11.3 (IQR 10.4 to 12.2); p < 0.001), longer length of stay (1 day (IQR 1 to 1) vs 2 days (IQR 2 to 3); p < 0.001), higher OARA score (median of 60.0 (IQR 40 to 75) vs 5.0 (IQR 0-35); p = 0.001), and total hip arthroplasty (p < 0.001). All patients who received a transfusion had an OARA score > 34; however, this did not reach statistical significance as a screening threshold. Conclusion Risk of blood transfusion after primary TJR was uncommon in our series, with an incidence of 1.19%. Transfusion was associated with OARA scores > 60. The OARA score, not American Society of Anesthesiologists grade, reliably identified patients at risk for postoperative blood transfusion. Selective Hb monitoring may result in substantial cost savings in the era of cost containment. Cite this article: Bone Joint J 2021;103-B(1):65–70.