Outcomes of a First Total Knee Arthroplasty Are Associated With Outcomes of the Subsequent Contralateral Total Knee Arthroplasty

BackgroundTo determine if preoperative characteristics and postoperative outcomes of a first total knee arthroplasty (TKA) were predictive of characteristics and outcomes of the subsequent contralateral TKA in the same patient.MethodsRetrospective administrative claims data from (SPARCS) database were analyzed for patients who underwent sequential TKAs from September 2015 to September 2017 (n = 5,331). Hierarchical multivariable Poisson regression (length of stay [LOS]) and multivariable logistic regression (all other outcomes), controlling for sex, age, and Elixhauser comorbidity scores were performed.ResultsThe cohort comprised 65% women, with an average age of 66 years and an average duration of 7.3 months between surgeries (SD: 4.7 months). LOS was significantly shorter for the second TKA (2.6 days) than for the first TKA (2.8 days; P < .001). Patients discharged to a facility after their first TKA had a probability of 76% of discharge to facility after the second TKA and were significantly more likely to be discharged to a facility compared with those discharged home after the first TKA (odds ratio [OR]: 63.7; 95% confidence interval [CI]: 52.1-77.8). The probability of a readmission at 30 and 90 days for the second TKA if the patient was readmitted for the first TKA was 1.0% (OR: 3.70; 95% CI: 0.98-14.0) and 6.4% (OR: 9; 95% CI: 5.1-16.0), respectively. Patients with complications after their first TKA had a 27% probability of a complication after the second TKA compared with a 1.6% probability if there was no complication during the first TKA (OR: 14.6; 95% CI: 7.8.1-27.2).ConclusionThe LOS, discharge disposition, 90-day readmission rate, and complication rate for a second contralateral TKA are strongly associated with the patient’s first TKA experience. The second surgery was found to be associated with an overall shorter LOS, fewer readmissions, and higher likelihood of home discharge.Level of EvidenceLevel 3-retrospective cohort study.     

Lower Limb Biomechanics in Individuals With Knee Osteoarthritis Before and After Total Knee Arthroplasty Surgery

We investigated the biomechanical changes that occur in the lower limb following total knee arthroplasty (TKA). Lower limb joint kinematics and kinetics were evaluated in 32 patients before and 12 months following TKA and 28 age-matched controls. Analysis of variance with Bonferroni-adjusted post-hoc tests showed no significant changes in knee joint kinematics and kinetics following TKA despite significant improvements in pain and function. Significant increases in peak ankle plantarflexion and dorsiflexion moments and ankle power generation were observed which may be a compensatory response to impaired knee function to allow sufficient power generation for propulsion. Differences in knee gait parameters may arise as a result of the presence of osteoarthritis and mechanical changes associated with TKA as well as retention of the pre-surgery gait pattern.     

Stair Ambulation Biomechanics Following Total Knee Arthroplasty: A Systematic Review

The purpose of this review was to summarize the biomechanical adaptations during stair ambulation that occur after total knee arthroplasty (TKA). Articles were identified by searching PubMed and Web of Science. During stair ascent, knee flexion angle at heel strike and walking velocity were reduced in TKA subjects compared to controls. Results of other variables were not consistent between studies. During stair descent only one study found any differences for knee moments in the sagittal and frontal plane between TKA subjects and controls. Other results during stair descent were not consistent between studies. Differences in methods can partially explain discrepancies between studies in this review. More studies with consistent and improved methods are needed in order to provide better understanding of stair ambulation following TKA.     

A Dual-Pivot Pattern Simulating Native Knee Kinematics Optimizes Functional Outcomes After Total Knee Arthroplasty

Background

Few studies on kinematics correlate patterns to functional outcomes after total knee arthroplasty (TKA). The purpose of this study was to determine if lateral pivot motion in early flexion and medial pivot in high flexion, simulating native knee kinematics, produces superior clinical outcomes. A second objective was to determine if specific kinematic patterns produce superior outcomes.

Clinical Outcomes Following the Use of Constrained Condylar Knees in Primary Total Knee Arthroplasty

Background

Certain clinical or adverse intraoperative situations require the use of increased constraint in primary total knee arthroplasty (TKA). These include significant angular deformities causing incompetent collateral ligaments, or inadvertent intraoperative injury to collateral structures as well as the inability to achieve a balanced flexion and extension gap. Clinical success has been described with the use of constrained condylar knee arthroplasty in the primary setting in these situations. Traditionally, increasing constraint has been in conjunction with intramedullary stems, referred to as stemmed constrained condylar knees (SCCK); however, some devices provide an intermediary option by increasing constraint without the use of stems, herein referred to as nonstemmed constrained condylar knees (NSCCK). The aim of this study was to compare the clinical outcomes of both these devices in primary TKA in terms of revision rates and change in outcome measures over the follow-up period.

The Effect of Total Knee Arthroplasty on Knee Joint Kinematics and Kinetics During Gait

This study determined how total knee arthroplasty (TKA) altered knee motion and loading during gait. Three-dimensional kinematic and kinetic gait patterns of 42 patients with severe knee osteoarthritis were collected 1 week prior and 1-year post-TKA. Principal component analysis extracted major patterns of variability in the gait waveforms. Overall and midstance knee adduction moment magnitude decreased. Overall knee flexion angle magnitude increased due to an increase during swing. Increases in the early stance knee flexion moment and late stance knee extension moment were found, indicating improved impact attenuation and function. A decrease in the early stance knee external rotation moment indicated alteration in the typical rotation mechanism. Most changes moved toward an asymptomatic pattern and would be considered improvements in motion, function, and loading.     

Intraoperative Medial Pivot Affects Deep Knee Flexion Angle and Patient-Reported Outcomes After Total Knee Arthroplasty

The aim of this study was to evaluate the relationship between clinical results including patient-reported outcomes and intraoperative knee kinematic patterns after total knee arthroplasty (TKA). A cross-sectional survey of forty consecutive medial osteoarthritis patients who had a primary TKA using a CT-based navigation system was conducted. Subjects were divided into two groups based on intraoperative kinematic patterns: a medial pivot group (n = 20) and a non-medial pivot group (n = 20). Subjective outcomes with the new Knee Society Score and clinical outcomes were evaluated. The functional activities, patient satisfaction and the knee flexion angle of the medial pivot group were significantly better than those of the non-medial pivot group. An intraoperative medial pivot pattern positively influences deep knee flexion and patient-reported outcomes.     

Short-to-Midterm Outcomes of Revision Total Knee Arthroplasty Patients With a Total Stabilizer Knee System

Background

Revision total knee arthroplasty (TKA) can often be challenging. The use of a new revision system may aid in providing better stability, improved function, fit, and implant longevity. Therefore, we assessed: (1) survivorship, (2) clinical outcomes, (3) postoperative complications, and (4) radiographic outcomes of patients who underwent revision TKA using this system.

Outcomes of Total Knee Arthroplasty Revisions in Obese and Morbidly Obese Patient Populations

BackgroundThe obese population is at higher risk for complications following primary total knee arthroplasty (TKA), but little data is available regarding revision outcomes. This study aimed to investigate the role of body mass index (BMI) in the cause for revision TKA and whether BMI classification is predictive of outcomes.MethodsA multi-institutional database was generated, including revision TKAs from 2012 to 2019. Data collection included demographics, comorbidities, surgery types (primary revision, repeat revision), reasons for revision, lengths of hospital stay, and surgical times. Patients were compared using 3 BMI categories: nonobese (18.5 to 29.9), obese (30 to 39.9), and morbidly obese (≥40). Categorical and continuous variables were analyzed using chi-square and 1-way analysis of variance tests, respectively. Regression analyses were used to compare reasons for revision among weight classes.ResultsObese and morbidly obese patients showed significant risk for repeat revision surgery in comparison to normal weight patients. Obese patients were at higher risk for primary revision due to stiffness/fibrosis and repeat revision due to malposition. In comparison to the obese population, morbidly obese patients were more likely to require primary revision for dislocation and implant loosening.ConclusionSignificant differences in primary and repeat revision etiologies exist among weight classes. Furthermore, obese and morbidly obese patients have a greater risk of requiring repeat revision surgery. These patients should be informed of their risk for multiple operations, and surgeons should be aware of the differences in revision etiologies when anticipating complications following primary TKA.     

Influence of Depression on Total Knee Arthroplasty Outcomes

It is not clear whether indicating TKA-surgery is advisable in depressed patients. A prospective cohort of 716 patients undergoing TKA was designed. SF36, KSS, WOMAC and VAS plus 2 satisfaction questions were evaluated. There were 2 groups: 200 patients were depressed and 516 were not. Preoperative/postoperative results show better scores for non-depressed patients on almost every sub-scale. Nevertheless, net change results (improvement) were quite similar: 65.74 improvement in depressed-KSS and 74.58 in non-depressed (P = 0.049); 8.93 net change in depressed-Physical Composite Score and 11.84 in non-depressed (P = 0.003); 2.38 in depressed-Mental Composite Score and − 0.61 in non-depressed (P = 0.024). Depressed patients obtained great improvement from preoperative at one-year follow-up and even greater than non-depressed patients in some domains. Moreover, satisfaction was similar. Therefore, TKA can be recommended to depressed patients.     

Clinical Decision Support Tools for Predicting Outcomes in Patients Undergoing Total Knee Arthroplasty: A Systematic Review

BackgroundTotal knee arthroplasty is the standard surgical treatment for end-stage osteoarthritis. Although widely accepted as a successful procedure, approximately 30% of patients are not satisfied due to non-optimal postoperative outcomes. Clinical decision support tools that are able to accurately predict post-surgery outcomes would assist in providing individualized advice or services to help alleviate possible issues, resulting in significant benefits to both the healthcare system and individuals.MethodsFive databases (Ovid Medline, Ovid EMBASE, CINAHL complete, Cochrane Library, and Scopus) were searched for the key phrases “knee replacement” or “knee arthroplasty” and “decision support tool,” “decision tool,” “predict1 tool,” “predict1 model,” “algorithm” or “nomogram.” Searches were limited to peer-reviewed journal articles published between January 2000 and June 2019. Reference lists of included articles were examined. Authors came to a consensus on the final list of included articles.ResultsEighteen articles were included for review. Most models reported low predictive success and inability to externally validate. Both candidate and final predictor variables were inconsistent between studies. Only 1 model was considered strongly predictive (AUROC >0.8), and only 2 studies were able to externally validate their developed model. In general, models that performed well used large patient numbers, were tested on similar demographics, and used either nonlinear input transformations or a completely nonlinear model.ConclusionSome models do show promise; however, there remains the question of whether the reported predictive success can continue to be replicated. Furthermore, clinical applicability and interpretation of predictive tools should be considered during development.     

Biomechanical Consequences of Patellar Component Medialization in Total Knee Arthroplasty

The optimal amount of patellar component medialization in knee arthroplasty is unknown. We measured the impact, on patellofemoral kinematics and contact force distribution, of 0.0-, 2.5-, and 5.0-mm patellar component medialization in 7 cadaveric specimens implanted with knee arthroplasty components. The knees were flexed dynamically in a weight-bearing rig. Medialization led to lateral shift of the patellar bone, slight medial shift of the patellar component in the femoral groove, lateral tilt of the patella, reduced patellofemoral contact force in later flexion, and lateral shift of the center of pressure in early flexion. Effects on shift and tilt were proportional to the amount of medialization. As a result of this investigation, we recommend medializing the patellar component slightly—on the order of 2.5 mm.     

Advanced Age Is Not a Barrier to Total Knee Arthroplasty: A Detailed Analysis of Outcomes and Complications in an Elderly Cohort Compared With Average Age Total Knee Arthroplasty Patients

BackgroundLife expectancy and higher complication rates have made the routine use of total knee arthroplasty (TKA) in elderly patients disputed by some authors. The purpose of this study was to assess patient and implant survivorship, complication and revision rates, and patient-reported outcomes (PROMS) in a cohort of patients aged above 80 years undergoing TKA. A comparison with a propensity matched cohort of patients of average age within our database for TKA was performed.MethodsA retrospective review of prospectively collected data identified 644 patients over the age of 80 years undergoing a TKA within a 14-year period. After calculating the average age of all TKA patients within the reviewed database, a cohort deemed average age was created within 1 standard deviation of the average age and matched using the following criteria: gender, surgeon, diagnosis, procedure type, and year. The primary outcomes were survivorship of the implant and the patient. The secondary outcomes were complications, transfusion rates, discharge destination, and PROMS.ResultsThe revision rate was low for both groups (P = .051). Implant survivorship at 10 years was similar (P = .07). Mortality rate was higher in the elderly (P < .001). General complication rate was higher in the elderly (P = .031). Surgical complications rates were similar (P = .702). The PROMS at final follow-up were 4% lower in the elderly (P < .001).ConclusionTKA in the elderly is a safe procedure. With measures minimizing the perioperative complications and blood loss, the outcome can be expected to be similar to patients of average age. The projected implant and patient survivorship in the elderly cohort is long enough to suggest that TKA in the elderly could have a high impact on remaining quality of life.Level III retrospective study.     

Effect of Tourniquet Use on Patient Outcomes After Cementless Total Knee Arthroplasty: A Randomized Controlled Trial

BackgroundTourniquet use is common in total knee arthroplasty (TKA), but debate exists regarding its use and effect on patient outcomes. The study purpose was to compare the effect of short tourniquet (ST) time vs long tourniquet (LT) time on pain, opioid consumption, and patient outcomes.MethodsPatients were prospectively randomized to an ST time of 10 min vs LT time. A total of 100 consecutive patients undergoing primary cementless robotic-assisted TKA underwent randomization, with 5 patients unable to complete follow-up, leaving 49 in the ST group and 46 in the LT cohort. Visual analog scale pain scores, morphine equivalent, serum creatine kinase, distance walked, range of motion, length of stay (LOS), surgical time, hemoglobin (Hgb), and Knee Society Scores (KSS) were prospectively collected.ResultsVisual analog scale pain was statistically equivalent at 24, 48, and 72 hours and at 2 and 6 weeks postoperatively. Morphine equivalent consumption was 36 vs 44 (P = .03), 48 vs 50 (P = .72), 31 vs 28 (P = .57), and 4.7 vs 5.5 (P = .75) in the LT vs ST cohorts at 24 hours, 48 hours, 2weeks, and 6weeks postoperatively. Change in Hgb postoperative day 1 was 2.7 in both groups (P = .975). Postoperative day 1 creatine kinase-MB was 3.7 and 3.0 (P = .30) in LT and ST cohorts. Six-week postoperative KSS Knee and Function scores were 82.4 and 70.5 in LT group vs 80.8 and 72.3 in ST group (P = .61 and P = .63). Postoperative range of motion, LOS, and surgical time were equivalent.ConclusionThis study demonstrates no significant advantage of ST use in primary TKA with respect to opioid consumption, patient-reported pain, KSS scores, LOS, or postoperative Hgb level.     

Perioperative Outcomes in Total Knee Arthroplasty for Non-English Speakers

BackgroundMany studies have demonstrated that in patients whose primary language is not English, outcomes after an orthopaedic surgery are worse compared to primary English speakers. The goal of this study was to compare perioperative outcomes in patients undergoing total knee arthroplasty (TKA) who prefer English as their first language versus those who prefer a different language.MethodsWe retrospectively reviewed all patients who underwent primary TKA from May 2012 to July 2021. Patients were separated into two groups based on whether English was their preferred primary language (PPL). Of the 13,447 patients who underwent primary TKA, 11,290 reported English as their PPL, and 2,157 preferred a language other than English. Patients whose PPL was not English were further stratified based on whether they requested interpreter services. Multiple regression analyses were performed to determine the significance of perioperative outcomes while controlling for demographic differences.ResultsOur analysis found that non-English PPL patients had significantly lower rates of readmission (P = .040), overall revision (P = .028), and manipulation under anesthesia (MUA; P = .025) within 90 days postoperatively. Sub analyses of the non-English PPL group showed that those who requested interpreter services had significantly lower 1-year revision (P < .001) and overall MUA (P = .049) rates.ConclusionOur results demonstrate that TKA patients who communicated in English without an interpreter were significantly more likely to undergo revision, readmission, and MUA. These findings may suggest that language barriers may make it more difficult to identify postoperative problems or concerns in non-English speakers, which may limit appropriate postoperative care.Level III EvidenceRetrospective Cohort Study.     

Interpretations of the Clinical Outcomes of the Nonresponders to Mail Surveys in Patients After Total Knee Arthroplasty

This study examined whether or not nonresponders to mail survey have poorer clinical outcomes than responders. A postal questionnaire, which was designed to evaluate the functional disability and patient's satisfaction, was mailed to 387 patients whose 1-year clinical outcomes were available. Of the 270 patients (69.8%) who responded, 247 (91.4%) reported that they were satisfied with their replaced knees. The knees of the nonresponders showed significantly poorer results in terms of the function-related scales (American Knee Society score function, Western Ontario McMaster University Osteoarthritis Index scale function, Short-Form 36 physical and functional scores) than the knees of the responders, whereas there were no significant differences in the pain-related scales. The clinical results of the nonresponders were poorer in most of the clinical outcome scales than those of the satisfied subgroup of responders but better than those of the dissatisfied subgroup. The results of the pain-related scales were similar to the satisfied subgroup but the function-related scales were similar to the dissatisfied subgroup.     

Influence of Total Knee Arthroplasty on Patellar Kinematics and Patellofemoral Pressure

Background

Patellofemoral complications are one of the main problems after total knee arthroplasty (TKA). The design of the TKA component may affect the patellar biomechanics, which may be associated with this postoperative complication. The purpose of this study was to assess the influence of TKA and prosthesis designs on the patellar kinematics and patellofemoral pressure.

Sex Differences in Gait After Total Knee Arthroplasty

Background

Before total knee arthroplasty (TKA), males walk with biomechanics that are distinct from females. It is not known whether these sex-specific profiles are maintained after TKA and whether any differences reflect those typical of unimpaired males and females. The aim of this study was to compare knee biomechanics of males and females with TKA with unimpaired controls during walking.

Predicting Functional Outcomes After Above Knee Amputation for Infected Total Knee Arthroplasty

Background

Above knee amputation (AKA) is a rare, but serious, complication of total knee arthroplasty with relatively poor functional outcomes. The purpose of this study was to identify the factors predicting ambulatory status after AKA for periprosthetic joint infection of the knee and to elucidate the effects of this procedure on general health outcomes.