Combined Meniscal Allograft Transplantation and Anterior Cruciate Ligament Reconstruction Show Good 2- to 14-Year Outcomes: A Systematic Review.

PURPOSE: To evaluate the clinical outcomes of anterior cruciate ligament reconstruction (ACLR) with meniscal allograft transplantation (MAT) through a systematic review of current available evidence. METHODS: A systematic database search of PubMed, Embase, Web of Science, and CINAHL was performed from inception up to December 7, 2021, in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses. Follow-up studies (inception cohort studies/nonrandomized controlled trials/retrospective cohort studies) and case series that had more than 10 people published in English and involved patients who underwent a combination of ACLR and MAT were included. The quality of these studies was appraised using the Cochrane Risk Of Bias In Non-randomized Studies of Interventions tool. Systematic review of International Knee Documentation Committee (IKDC), Lysholm, and Tegner activity scores were conducted. RESULTS: Seven studies involving 363 patients were included. The average mean follow-up time was 4.08 years, ranging from 1.75 to 14 years. All studies used the Lysholm Knee Scoring system to report clinical outcomes, whereas 2 studies and 4 studies used the IKDC Questionnaire and Tegner activity scale respectively to measure clinical outcomes postoperatively. Comparing postoperative with preoperative scores, we found an improvement above the minimal clinically important difference for the Lysholm (mean difference [MD] range 16.00-26.10) and Tegner activity scores (MD range 1.50-1.90). All but one study reported an increase above the minimal clinically important difference for IKDC scores postoperatively (MD range 5.60-23.00). CONCLUSIONS: Combined MAT and ACLR have good 2- to 14-year clinical outcomes postoperatively and is an optimal procedure for patients with concurrent ACL injuries with irreparable meniscus injuries. LEVEL OF EVIDENCE: IV, systematic review and/or meta-analysis of studies with Levels I to IV.

Three Doses of Platelet-Rich Plasma Therapy Are More Effective Than One Dose of Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Systematic Review and Meta-analysis.

PURPOSE: To compare the efficacy of a single dose of platelet-rich plasma (PRP) with multiple doses of PRP therapy in the treatment of knee osteoarthritis (KOA). METHODS: The PubMed, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Scopus, and Cochrane Library databases were searched from database inception to May 2022; in addition, the gray literature and bibliographic references were searched. Only randomized controlled trials comparing the effect of a single dose versus multiple doses of PRP for KOA were included. Literature retrieval and data extraction were conducted by 3 independent reviewers. The inclusion and exclusion criteria were based on type of study, research subjects, intervention, outcome, language, and availability of data. Pooled analyses of visual analog scale (VAS) scores, Western Ontario and McMaster Universities Arthritis Index scores, and adverse events were conducted. RESULTS: Seven studies (all randomized controlled trials) of high methodologic quality involving 575 patients were included. The ages of the patients included in this study ranged from 20 to 80 years, and the sex ratio was balanced. Triple-dose PRP therapy resulted in significantly better VAS scores compared with single-dose PRP therapy at 12 months (P < .0001), with no significant change in VAS scores between double-dose PRP and single-dose PRP at 12 months. Regarding adverse events, double-dose (P = .28) and triple-dose (P = .24) therapy showed no significant differences in safety from single-dose therapy. CONCLUSIONS: Although there is a paucity of large high-quality Level I studies, current best evidence suggests that 3 doses of PRP for KOA are more effective than 1 dose of PRP at providing pain relief up to 1 year after administration. LEVEL OF EVIDENCE: Level II, systematic review of Level II studies.

Enoxaparin Versus Direct Oral Anticoagulants for Venous Thromboembolism in Asians Undergoing Total Knee Arthroplasty: A Meta-Analysis and Systematic Review.

BACKGROUND: The introduction of direct oral anticoagulants (DOACs) shows promise for their role as a chemoprophylaxis agent after total knee arthroplasty (TKA) for the prevention of venous thromboembolism (VTE). However, existing studies are largely based on Western populations that do not account for the different risk profiles and lower rates of VTE in Asians. This systematic review and meta-analysis aimed to evaluate the efficacy of DOACs compared with enoxaparin in an Asian-based population study. METHODS: The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies that compared outcomes between enoxaparin and DOACs as VTE prophylaxis after TKA in the Asian population were included. RESULTS: Five studies with 121,153 patients were included. DOACs demonstrated a convincing benefit over enoxaparin in overall VTE prevention (odds ratio [OR] = 0.42, 95% confidence interval [CI]: 0.24-0.74). However, although the OR trended in favor of DOACs for the reduction of deep vein thrombosis events (OR = 0.54, 95% CI: 0.20-1.48) and pulmonary embolism (OR = 0.75, 95% CI: 0.07-8.20), statistical significance was not reached. In terms of bleeding complications, both arms had similar rates of major (0.91% vs 0.20%), clinically relevant nonmajor (3.28% vs 2.94%), and minor bleeding complications (12.8 vs 13.3%). A nonsignificance advantage of enoxaparin over DOACs was revealed in the OR for major bleeding (OR = 3.17; 95% CI: 0.81-12.43), whereas DOACs were favored to reduce risk of clinically relevant nonmajor (OR = 0.82; 95% CI: 0.01-91.51) and minor bleeding (OR = 0.76; 95% CI: 0.11-5.33). CONCLUSION: DOACs confer a significantly reduced rate of overall VTE compared with enoxaparin in Asians after TKA. No significant differences in deep vein thrombosis, pulmonary embolism, and rates of bleeding complications exist.

Effectiveness of Sensor-based Rehabilitation in Improving Outcomes in Patients Undergoing Total Knee Arthroplasty.

BACKGROUND: Physical rehabilitation after total knee arthroplasty (TKA) is important for long-term functional recovery. Recently, sensor-based home rehabilitation (SHR) has gained prominence as a promising method that allows monitoring and guidance that is both structured and accessible, compared to traditional methods of physical rehabilitation. Despite the advent of wearable sensor systems, there is a paucity of evidence regarding SHR in the current literature. Thus, this systematic review aimed to evaluate the effect of wearable SHR on post-TKA outcomes. METHODS: We performed a systematic search of three electronic databases from the beginning of record to March 12, 2021. Primary outcomes were patient-reported outcome measures (PROMs) after rehabilitation, including the Knee Injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Knee Society Score (KSS). Secondary outcomes were physical activity levels and functional performance including range of motion (ROM) and Timed Up and Go Test (TUG). RESULTS: A total of 16 studies involving 1321 subjects were included. All wearable sensors in our included studies involved a combination of accelerometers, gyroscopes and magnetometers as functional units. These studies reported favourable outcomes for all three PROMs, although the extent of improvement in specific domains varied among studies. Moreover, physical activity in terms of daily steps and time spent on physical activity increased post-rehabilitation. Similarly, there were improvements in ROM and TUG that reflected a favourable post-operative trajectory during rehabilitation. CONCLUSION: SHR is effective for improving subjective and objective outcomes post-TKA. The role of SHR should be evaluated by a dedicated cost-benefit analysis to facilitate its wider adoption in healthcare systems.

Bony asymmetry in patellofemoral morphology and risk factors of instability are mostly clinically negligible.

PURPOSE: Previous investigations suggested that femoral side-to-side differences were located in the upper femur anatomy. However, little is known about the asymmetry between distal femur and patella. The degree of bony asymmetry in the patellofemoral joint was evaluated using pairs of CT-scans with emphasis on morphometric measurements and risk factors relevant to patellofemoral disorders. METHODS: Patellofemoral morphometric parameters and anatomical risk factors were analyzed from 345 pairs of CT scans to evaluate side-to-side differences for each patient. All measurements were automatized using previously published algorithm-calculated bone landmarks. We analyzed asymmetry based on absolute differences (AD) and percentage asymmetry (AS%). Significant asymmetry was defined as AS% > 10%. RESULTS: Patellar height was found to be highly symmetric (mean AD 0.1 for both Insall-Salvatti and Caton-Deschamps methods, AS% 8% and 9%, respectively). Patellar and femoral morphometric parameters were found highly symmetric, except for the trochlear groove depth. Substantial asymmetry was reported in two patellofemoral risk factors: the lateral trochlear inclination (mean AD 2°, AS% 16%) and the tibial tuberosity-trochlear groove distance (1 mm, 116%). Patellar and femoral morphometric asymmetries were independent of demographics, including age, gender, height, weight and ethnicity. CONCLUSION: Patellar height was found to be highly symmetric and is, therefore, a reasonable index for contralateral templating. While very few patellofemoral morphometric parameters and anatomical risk factors were asymmetric, the mean differences were clinically negligible and independent of demographics. LEVEL OF EVIDENCE: III.

Early post-operative oxford knee score and knee society score predict patient satisfaction 2 years after total knee arthroplasty.

BACKGROUND: There is poor correlation between functional outcomes and patient satisfaction following total knee arthroplasty (TKA). We asked if early post-operative scores at 6 months or the pre- to post-operative change in scores are predictive of patient satisfaction 2 years after TKA. METHODS: We conducted a retrospective review of prospectively collected registry data of 4359 TKAs performed at a single institution. At 6 months and 2 years, the Knee Society Score (KSS), Oxford Knee Score (OKS), and Short-Form 36 scores were assessed. A satisfaction questionnaire was also completed. Logistic regression was used to generate receiver-operating characteristic (ROC) curves to assess the ability of each scoring system in predicting satisfaction at 2 years. RESULTS: At 2 years, 91.1% of patients were satisfied. For the absolute post-operative OKS at 6 months, an AUC of 0.762 (95% CI 0.736-0.788) and a threshold of ≤ 21.5 points (or ≥ 38.5 points on the new scale) were obtained. For the KSS knee score, an AUC of 0.704 (95% CI 0.674-0.734) and a threshold of ≥ 80.5 points were identified. The OKS performed significantly better than the KSS knee score (p = 0.03) and the other post-operative scores (p < 0.001). When analysing the change in scores pre-operatively to 6 months, the AUC was < 0.7 for all scales. CONCLUSIONS: Early post-operative scores, specifically the OKS and KSS knee score, can predict patient satisfaction at 2 years after TKA with good accuracy. The threshold values offer surgeons an additional tool to identify patients at risk of dissatisfaction at 2 years, enabling them to intervene earlier to ensure good patient satisfaction. LEVEL OF EVIDENCE: III, retrospective cohort study.

Patterns of Weight Change and Their Effects on Clinical Outcomes Following Total Knee Arthroplasty in an Asian Population.

BACKGROUND: This prospective cohort study was designed to evaluate weight change patterns and their effects on clinical outcomes following total knee arthroplasty (TKA) in the Asian population. We hypothesized that Asian patients will have a different pattern of weight change following TKA compared to Western patients and that weight loss following TKA will be associated with better clinical outcomes. METHODS: A cohort of consecutive patients who underwent TKA from 2004 to 2015 was included. All patients received a conventional posterior-stabilized TKA implant and underwent a standard perioperative care pathway. Assessments were done preoperatively, at 6 months, and 2 years after surgery. The range of motion, Knee Society Score, Oxford Knee Score, and the Short-Form 36 questionnaire were used to assess outcomes. Height and weight of patients were recorded for body mass index (BMI) calculation. Patterns of weight loss following TKA in this cohort were charted. Clinical outcomes were then analyzed against the change in BMI. RESULTS: A total of 602 patients (602 knees) were reviewed. Mean age was 66.39 ± 7.27 years. Mean BMI was 27.75 ± 4.51 kg/m2. Overall, 63.12% of all our patients gained weight following TKA. Moreover, weight loss did not influence patients' odds for better clinical outcomes. Furthermore, patients who were in the preoperative BMI category of obese class I were more likely to gain weight as compared to those in the normal category (odds ratio 0.35, 95% confidence interval 0.2-0.61, P < .001). Moreover, older people were more likely to gain more weight compared to younger people. We also showed that the mean 2-year Knee Society Knee Score was significantly higher in the patients who gained weight while the patients who lost weight had the highest mean 2-year Oxford Knee Score and the lowest mean 2-year Knee Society Function Score. CONCLUSION: Asians tend to gain weight following TKA. However, this weight change following TKA does not affect clinical outcomes, which remain good across all BMI groups. LEVEL OF EVIDENCE: Therapeutic Level III.

Cervical pedicle screw instrumentation is more reliable with O-arm-based 3D navigation: analysis of cervical pedicle screw placement accuracy with O-arm-based 3D navigation.

PURPOSE: Despite proven biomechanical superiority and resultant superior clinical outcomes, pedicle instrumentation in cervical spine is not widely practiced due to technical difficulties, steep learning curve, and possible potential catastrophic complications due to screw misplacement. This study was undertaken with the purpose to evaluate the feasibility, accuracy, and complications of cervical pedicle screw instrumentation solely using O-arm-based 3D navigation technology. METHODS: Prospectively maintained data from a single-surgeon case series were retrospectively analyzed. All the patients had undergone cervical pedicle instrumentation under O-arm 3D navigation. Screw placement accuracy was analyzed and compared among different vertebral levels and also between different patient groups. RESULTS: A total of 241 cervical pedicle screws were inserted in 44 patients. Out of the 241 screws, 197 (81.74%) were inserted at the level of C3-C6 vertebrae with nearly equal distribution among the 4 vertebrae, followed by 32 (13.28%) and 12 (4.98%) screws at C2 and C7 vertebrae, respectively. After the analysis of screw placement as per Gertzbein classification, the overall breach rates were found to be 7.05% (17 screws) with 52.94% (10 screws) Grade I, 47.06% (7 screws) Grade II, and nil Grade III screw breaches. CONCLUSION: The use of O-arm-based intra-operative 3D scans for navigation can make cervical pedicle screw placement reliable. High accuracy and better intra-operative control can increase surgeon's confidence in using cervical pedicle instrumentation on more regular basis. These slides can be retrieved under Electronic Supplementary Material.

Correction to: Cervical pedicle screw instrumentation is more reliable with O-arm-based 3D navigation: analysis of cervical pedicle screw placement accuracy with O-arm-based 3D navigation.

Unfortunately, the second author name of the above-mentioned article was incorrectly published in original publication. The complete correct name is given below: Hamid Rahmatullah Bin Abd Razak. The original article has been corrected.

Unicompartmental Knee Arthroplasty Achieves Greater Flexion With No Difference in Functional Outcome, Quality of Life, and Satisfaction vs Total Knee Arthroplasty in Patients Younger Than 55 Years. A Propensity Score-Matched Cohort Analysis.

BACKGROUND: Improvements in surgical techniques, implant design, and adherence to indications have resulted in favorable outcomes after unicompartmental knee arthroplasty (UKA), particularly in an older population. However, no studies have compared the performance of contemporary UKA and total knee arthroplasty (TKA) in a young population. METHODS: Prospectively collected registry data of 160 UKAs performed in 160 patients younger than 55 years were reviewed. Propensity scores generated using logistic regression were used to adjust for confounding variables of age, gender, body mass index, preoperative range of motion, Knee Society Score, Oxford Knee Score, and Short-Form 36, allowing matching of the TKA cohort to the UKA cohort in a 1:1 ratio using the nearest-neighbor method. RESULTS: The UKA group had significantly greater flexion at 6 months and 2 years (P < .001). There was no significant difference in Knee Society Score, Oxford Knee Score, and Short-Form 36. At 2 years, 89.4% and 88.8% of the TKA and UKA groups were satisfied (P = 1.00) while 86.9% and 86.3% had their expectations fulfilled (P = 1.00). At a mean follow-up of 7 years, there were 2 revisions in each group (2.2%). CONCLUSION: Although native knee biomechanics are preserved, younger patients do not seem to perceive this oft-cited benefit of UKA, as this did not translate into greater health-related quality of life or patient satisfaction compared to TKA. The theoretical advantages of UKA were not borne out by our findings, other than greater flexion up to 2 years postoperatively.

Short-term outcomes of arthroscopic TightRope® fixation are better than hook plate fixation in acute unstable acromioclavicular joint dislocations.

AIM: The aim of this study was to compare the short-term outcomes of arthroscopic TightRope® fixation with that of hook plate fixation in patients with acute unstable acromioclavicular joint dislocations. PATIENTS AND METHODS: We conducted a prospective case-control study of twenty-six patients with an acute ACJ dislocation who underwent surgical repair with either an arthroscopic TightRope® fixation or a hook plate from 2013 to 2016. Clinical and radiological data were collected prospectively. Clinical outcomes were evaluated using the Constant Score, the University of California at Los Angeles (UCLA) Shoulder Score, Oxford Shoulder Score as well as the visual analogue scale. Radiological outcomes were assessed with the coracoclavicular distance (CCD). RESULTS: Sixteen patients underwent arthroscopic TightRope® fixation, while 10 patients underwent hook plate fixation. There were no significant differences in the preoperative variables except for the mean UCLA 4b infraspinatus score (TightRope® 2.8 vs. hook plate 3.8; p = 0.030). Duration of surgery was significantly longer in the TightRope® group. At 1 year post-operatively, the TightRope® group had a significantly better Constant Score and CCD with no complications. All patients with hook plate fixation had to undergo a second procedure for removal of implant, and 3 patients had complications. CONCLUSIONS: Arthroscopic TightRope® fixation is a good option for the treatment of acute unstable ACJ dislocations. It has better short-term clinical and radiological outcomes as well as lesser complications when compared to hook plate fixation. LEVEL OF EVIDENCE: Therapeutic, Level III.

Prevalence of Venous Thromboembolic Events Is Low in Asians After Total Knee Arthroplasty Without Chemoprophylaxis.

BACKGROUND: This retrospective cohort study was designed to establish the prevalence of clinically significant venous thromboembolic events (VTE) in our patients undergoing total knee arthroplasty (TKA) without chemoprophylaxis. METHODS: A single-surgeon cohort of patients who underwent TKA from 2006 to 2014 were included. All patients had a pneumatic tourniquet applied and a drain inserted postoperatively. Tranexamic acid was not used perioperatively. All patients were under a standardized postoperative protocol with routine mechanical prophylaxis against VTE. None of the patients received prophylactic anticoagulation. All patients ambulated on the second postoperative day. Only symptomatic patients were referred for radiological examination to exclude VTE. We evaluated the patient demographics and calculated the prevalence of VTE in our cohort. RESULTS: A total of 966 patients were reviewed. Mean age was 66.1 ± 7.8 years. Mean body mass index was 28.2 ± 4.7 kg/m2. Mean tourniquet time was 53 ± 23 minutes. Patients stayed in hospital for a mean of 5.4 ± 3.1 days. There was 100% compliance to mechanical prophylaxis. And 11.1% of our patients were on concomitant antiplatelet or anticoagulant use. There were 8 patients with clinically significant VTE. This translates to a prevalence of 0.82%. Seven patients developed deep vein thrombosis and 1 patient died from massive pulmonary embolism. CONCLUSION: The prevalence of clinically significant VTE in our patients who underwent TKA without routine chemoprophylaxis is 0.82%. With proper patient selection, risk stratification, and stringent perioperative protocols, routine chemoprophylaxis may not be necessary in Asians undergoing TKA.

Intraoperative Measurements of Joint Line Changes Using Computer Navigation Do Not Correlate With Postoperative Radiographic Measurements in Total Knee Arthroplasty.

BACKGROUND: The adverse effects of joint line (JL) changes on kinematics and outcomes of total knee arthroplasty (TKA) have been studied. Some authors have quantified JL changes using intraoperative data from computer navigation, despite no studies validating these measurements to date. We designed a prospective study to determine whether intraoperative measurements of JL changes using computer navigation correlate with measurements obtained on weight-bearing radiographs postoperatively. METHODS: A total of 195 consecutive patients (195 knees) underwent computer-navigated cruciate-retaining TKA by the senior author. Twenty-four patients had missing radiographic data and were excluded from the study. The final JL change was calculated intraoperatively from the verified bony cuts and planned JL change as determined by the computer. JL position was also measured on preoperative and postoperative radiographs using an anteroposterior method. RESULTS: One hundred seventy-one knees were evaluated. Using computer-navigated and radiographic measurements, the mean JL change was 1.95 ± 1.5 mm (0-8.0 mm) and 4.05 ± 2.9 mm (0-17.3 mm), respectively. One hundred fourteen (67%) vs 129 (75%) had JL elevation, 44 (26%) vs 30 (18%) had JL depression, and 13 (7%) vs 12 (7%) had no JL change, respectively. Inter-rater and intrarater reliability of radiographic measurements was excellent. We found a poor correlation between computer-navigated and radiographic measurements (r = 0.303). CONCLUSION: There is a poor correlation between computer-aided and radiographic measurements of JL changes post-TKA. Elevation/depression of the JL needs to be considered in patients who remain symptomatic despite TKA, although the optimal method of assessment remains uncertain.

Obesity Does Not Affect Outcomes in Hybrid Versus Cemented Total Knee Arthroplasty in Asians.

BACKGROUND: This study aims to evaluate patient reported and functional outcomes following hybrid versus cemented total knee arthroplasty (TKA) in patients, stratified by body mass index (BMI). METHODS: Registry data of patients undergoing primary TKA between January 2004 and January 2013 were collected. Baseline interviews were conducted preoperatively to assess sociodemographic characteristics, BMI, and knee arthritis severity, using the Knee Society Score which consists of the Knee Society Knee Score and the Knee Society Function Score (KSFS) and Oxford Knee Score (OKS). These scores were collected prospectively, preoperatively, and postoperatively up to 2 years. Two-year outcomes and 5-year revision rates were then compared between (1) hybrid and cemented TKA groups and (2) BMI subclasses within the hybrid and cemented TKA groups. RESULTS: Patients who underwent cemented TKA had marginally better flexion range, KSFS, and OKS at 2 years postoperatively. In the overweight category, flexion range, KSFS, and OKS were marginally lower for hybrid TKAs. There were no differences in outcomes between the 2 groups in Class I and II obesity. Within the cemented TKA group, there were no differences in the outcomes between BMI subclasses. There were significant differences in the KSFS (0.023) and OKS (0.030) between the BMI subclasses within the hybrid TKA group, with patients in Class II obesity faring the worst. There was no statistically significant difference in the revision rates. CONCLUSION: We conclude that obesity does not affect outcomes in hybrid versus cemented TKA.

Patient-Reported Outcomes, Quality of Life, and Satisfaction Rates in Young Patients Aged 50 Years or Younger After Total Knee Arthroplasty.

BACKGROUND: Recent studies have shown a discrepancy between traditional functional outcomes and patient satisfaction, with some reporting less than 85% satisfaction in older patients undergoing total knee arthroplasty (TKA). As native knee biomechanics are not completely replicated, the resulting functional limitations may cause dissatisfaction in higher-demand individuals. Few studies have recorded patient-reported outcomes, health-related quality of life scores, and patient satisfaction in a young population undergoing TKA. METHODS: One hundred thirty-six primary TKAs were performed in 114 patients aged 50 years or younger (mean age, 47.0 years; range, 30-50 years) at a single institution. The main diagnoses were osteoarthritis (85%) and rheumatoid arthritis (10%). RESULTS: The range of motion, Knee Society Score, Oxford Knee Score, and Physical and Mental Component Scores of Short Form-36 increased significantly (P < .001). At 2 years, 85.3% of patients had good/excellent knee scores, 71.3% had good/excellent function scores, 94.9% met the minimal clinically important difference for the Oxford Knee Score, and 84.6% met the minimal clinically important difference for the Physical Component Score. We found that 88.8% of patients were satisfied with their surgeries, whereas 86.8% had their expectations fulfilled. Survivorship using revision as an end point was 97.8% at a mean of 7 years (range, 3-16 years). CONCLUSION: Patients aged 50 years or younger undergoing TKA can experience significant improvements in their quality of life, have their expectations met, and be satisfied with their surgeries, at rates similar to those of non-age-restricted populations. Surgeons should inform them of these benefits and the potential risk of revision surgery in the future, albeit increasingly shown to be low.

What Are the Preoperative Outcome Measures That Predispose to Periprosthetic Fractures After Primary Total Knee Arthroplasty?

BACKGROUND: There is little known in the literature about whether preoperative patient-reported outcome measures (PROMs) would affect the risk of periprosthetic fractures (PPFs) after primary total knee arthroplasty (TKA). Our study aims to evaluate the predictive values of PROMs on PPF after primary TKA. We hypothesize that poorer PROMs are associated with a higher risk of PPF after primary TKA. METHODS: We reviewed prospectively collected data in our hospital arthroplasty registry. Patients who sustained PPF after primary TKA between 2000 and 2015 were identified. Forty-two patients were identified and matched for gender, age, and body mass index to a control group of 84 patients who had primary TKA without PPF in a 2:1 ratio. Preoperative demographics, Short Form-36 (SF-36) scores, Oxford Knee score and Knee Society Score were evaluated. Variables of PROMs were entered into a multivariate logistic regression model. A variable was considered to be a significant predictor if its odds ratio was significant at P < .05. RESULTS: After multivariate regression analysis, SF-36 subdomains of physical functioning (PF) and vitality (VT) were identified as significant predictors for PPFs after primary TKA. A lower SF-36 PF and VT scores were associated with higher risks of sustaining a PPF after primary TKA. CONCLUSION: From our study, low preoperative SF-36 PF and VT scores are associated with a higher risk of PPFs after primary TKA. These results can allow the preoperative identification of patients at higher risk of PPF, and appropriate preoperative counseling, optimization, and close follow-up can be instituted for this at-risk group.

Preoperative haemoglobin cut-off values for the prediction of post-operative transfusion in total knee arthroplasty.

PURPOSE: The purpose of this study is to determine preoperative haemoglobin cut-off values that could accurately predict post-operative transfusion outcome in patients undergoing primary unilateral total knee arthroplasty (TKA). This will allow surgeons to provide selective preoperative type and screen to only patients at high risk of transfusion. METHODS: A total of 1457 patients diagnosed with osteoarthritis and underwent primary unilateral TKA between January 2012 and December 2014 were retrospectively reviewed. Logistic regression analyses were applied to identify factors that could predict transfusion outcome. RESULTS: A total of 37 patients (2.5 %) were transfused postoperatively. Univariate analysis revealed preoperative haemoglobin (p < 0.001), age (p < 0.001), preoperative haematocrit (p < 0.001), and preoperative creatinine (p < 0.001) to be significant predictors. In the multivariate analysis with patients dichotomised at 70 years of age, preoperative haemoglobin remained significant with adjusted odds ratio of 0.33. Receiver operating characteristic curve identified the preoperative haemoglobin cut-off values to be 12.4 g/dL (AUC = 0.86, sensitivity = 87.5 %, specificity = 77.2 %) and 12.1 g/dL (AUC = 0.85, sensitivity = 69.2 %, specificity = 87.1 %) for age above and below 70, respectively. CONCLUSIONS: The authors recommend preoperative haemoglobin cut-off values of 12.4 g/dL for age above 70 and 12.1 g/dL for age below 70 to be used to predict post-operative transfusion requirements in TKA. To maximise the utilisation of blood resources, the authors recommend that only patients with haemoglobin level below the cut-off should receive routine preoperative type and screen before TKA. LEVEL OF EVIDENCE: IV.

Obesity and Venous Thromboembolism in Total Knee Arthroplasty Patients in an Asian Population.

BACKGROUND: Venous thromboembolism (VTE) is a known complication of total knee arthroplasty (TKA). In addition, obesity has been implicated as a risk factor and justification for chemoprophylaxis for VTE. We wanted to review the prevalence of VTE among our patients and evaluate the incidence rates of VTE among nonobese and obese patients. METHODS: We reviewed 894 patients who underwent elective unilateral total knee arthroplasty by a single surgeon from March 2003 to November 2014 in our center. Any patients with clinically significant symptoms or signs of VTE such as deep venous thrombosis (DVT) or pulmonary embolism (PE) were diagnosed radiologically. The patient demographics analyzed included age, gender, body mass index, the number of comorbid diseases, and a history of hyperlipidemia. RESULTS: We found the incidence of VTE of 0.67% in our patients (6 patients of 894). Four of the 6 patients (66.7%) who developed DVT and PE belonged to nonobese group. The frequency of VTE in nonobese patients was 0.65% and 0.73% in the obese patients. There were no significant differences in age, number of comorbidities, and a history of hyperlipidemia between those who developed DVT and PE and those who did not. CONCLUSION: With the low prevalence of VTE among our study population, including patients with obesity, advanced age, multiple comorbidities, or hyperlipidemia, the practice of routine chemoprophylaxis should be reviewed.

Correlations Between Functional Knee Outcomes and Health-Related Quality of Life After Total Knee Arthroplasty in an Asian Population.

BACKGROUND: Current literature evaluating postoperative outcomes after total knee arthroplasty for osteoarthritis in the Asian population is sparse. We aimed to evaluate correlations between improvements in knee outcomes vs changes in generic health-related quality of life. METHODS: Postoperative outcomes were collected prospectively for 369 patients and compared at a 2-year follow-up using Short-Form 36 (SF-36), Knee Society Score (KSS), and Oxford Knee Score (OKS). The Spearman correlation coefficient was used to evaluate the strength of correlation between changes in knee scores (KSS and OKS) vs changes in each domain of the SF-36 scores. RESULTS: All parameters achieved statistically significant improvements (P < .05) in postoperative scores at 2-year follow-up with the exception of general health (P = .221) component of SF-36. For KSS knee score, there was low correlation with bodily pain (0.32). For KSS function score, there was moderate correlation with physical functioning (0.57) and low correlation with role physical (0.31) and social functioning (0.36). For OKS, there was moderate correlation with physical functioning (0.61) and social functioning (0.54) and low correlation with role physical (0.38) and bodily pain (0.50). All other parameters of SF-36 showed little correlation (<0.3). CONCLUSION: Improvements in knee-specific outcomes (KSS and OKS) after total knee arthroplasty correlate well with improvements in physical domains of health-related quality of life (SF-36) but poorly with the mental and social health domains.

Factors Affecting Wear of Constrained Polyethylene Tibial Inserts in Total Knee Arthroplasty.

BACKGROUND: Wear in posterior-stabilized (PS) polyethylene tibial inserts depends on component position, limb alignment, and ligament balancing. Valgus-varus constrained (VVC) inserts are likely to be affected similarly. We aimed to compare wear characteristics of VVC and PS inserts and identify associated factors. METHODS: This was a retrieval analysis (macroscopic and radiographic) of all 18 VVC liners collected from patients who underwent revision surgery from 1999 to 2011. These patients were matched to another group with PS inserts who underwent revision in the same time period. RESULTS: There was significantly more damage in the posts of the VVC group (13.0 ± 5.0, compared to 4.7 ± 1.9 in the PS group; P < .001). Within the VVC group, the total damage score and cold flow damage were significantly higher with excessive joint line changes (≥5 mm; P = .01). The excessive joint line elevation was associated with rotational wear pattern of the post (P = .004). Damage scores were increased with femoral component malposition (P = .04), anterior tibial slope (P = .04), and tibial component malposition (P = .04). CONCLUSION: Joint line elevation, femoral and tibial component malposition, and anterior tibial slope resulted in significantly more wear in the VVC inserts. Joint line elevation of >5 mm resulted in wear of the medial and lateral aspects of the post, femoral valgus resulted in cold flow wear of the anterior post, and tibial valgus and anterior slope resulted in wear of lateral aspect of the post.