Outcomes Vary Significantly Using a Tiered Approach to Define Success After Total Knee Arthroplasty

BackgroundPatient-reported outcome measures (PROM) allow assessment of clinical outcomes following primary total knee arthroplasty (TKA). The purpose of this study is to use progressively more stringent definitions of success to examine clinical outcomes of primary TKA at 1 year postoperatively and to determine which demographic variables were associated with achieving clinical success.MethodsThe American Joint Replacement Registry was queried from 2012 to 2020 for primary TKA. Patients who completed the following PROMs preoperatively and 1 year postoperatively were included: Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and KOOS for Joint Replacement (KOOS JR). Mean PROM scores were determined for each visit and between-visit changes were evaluated using paired t-tests. Rates of achievement of minimal clinically important difference (MCID) by distribution-based and anchor-based criteria, Patient Acceptable Symptom State, and substantial clinical benefit were calculated. Logistic regression was used to evaluate the association between demographic variables and odds of clinical success.ResultsIn total, 12,341 TKAs were included. Mean improvement in PROM scores were as follows: KOOS JR, 29; WOMAC-Pain, 33; and WOMAC-Function, 31 (P < .0001 for all). Rates of achievement of each metric were the following: distribution-based MCID, 84%-87%; anchor-based MCID, 46%-79%; Patient Acceptable Symptom State, 54%-82%; and substantial clinical benefit, 68%-81%. Patient age and gender were the most influential demographic factors on achievement of clinical success.ConclusionClinical outcomes at 1 year following TKA vary significantly when using a tiered approach to define success. A tiered approach to interpretation of PROMs should be considered for future research and clinical assessment.     

A Smartwatch Paired With A Mobile Application Provides Postoperative Self-Directed Rehabilitation Without Compromising Total Knee Arthroplasty Outcomes: A Randomized Controlled Trial

BackgroundSelf-directed rehabilitation (SDR) after total knee arthroplasty (TKA) has not been traditionally recommended. The purpose of this study was to determine if there was an impact on postoperative outcomes with the use of an SDR program after primary TKA.MethodsIn this prospective, randomized, multicenter, controlled trial, we paired a smartwatch with a mobile application, providing an SDR program after TKA. Three groups were examined in this level I study: (1) control group (formal physical therapy [PT]), (2) high exercise compliance group, and (3) low exercise compliance group. Patient-reported outcome measures (PROMs) of knee injury and osteoarthritis outcome scores, joint replacement (KOOS, JR), and EuroQol five-dimension five-level (EQ-5D-5L) along with range of motion (ROM) and manipulation rates were evaluated.ResultsThree hundred thirty-seven patients were enrolled in two groups with 184 in the control group and 153 in the study groups (90 in the high-compliance group and 63 in the low-compliance group). The KOOS, JR score was statistically lower in the low-compliance group in net change from preoperative scores at 3 months (P = .046) and 6 months (P = .032) than that in the control group; difference was noted at 6 months for the high-compliance group, P = .036. However, these did not meet the threshold of 8.02 units for KOOS JR minimal clinically important difference. No differences were seen in PROMs at other time intervals and in manipulation rates or ROM.ConclusionPostoperative outcomes including manipulation under anesthesia, ROM, and PROMs were not different when a smartwatch paired with a self-directed PT mobile application was compared with traditional formal PT. Surgeons can consider this an appropriate alternative to traditional PT programs after TKA.     

The Short Form KOOS,JR Is Valid for Revision Knee Arthroplasty

BackgroundThe Knee Injury Osteoarthritis Outcome Survey, Joint Replacement (KOOS, JR) is a reliable, responsive, and validated patient-reported outcome measure (PROM) of knee health in patients with knee osteoarthritis undergoing unilateral primary total knee arthroplasty (TKA). The validity of the KOOS, JR for revision TKA remains unknown.MethodsWe identified 314 patients who underwent revision TKA and had completed preoperative and 2-year postoperative PROMs. Validation included assessment of local dependence, unidimensionality, internal consistency, external construct validity, responsiveness, and floor effects preoperatively and ceiling effects at 2 years postoperatively.ResultsAmong patients undergoing revision TKA, the KOOS, JR demonstrated an absence of residual item correlation, adequate unidimensionality, high internal consistency (Person Separation Index: 0.897), and high external construct validity with existing validated PROMs, including KOOS Pain (Spearman’s correlation coefficient 0.89) and KOOS activities of daily living (0.90) domains. The KOOS, JR was more responsive (standardized response means: 1.14) to revision TKA than other common knee PROMs. Three percent of revision TKA patients were at the floor (lowest score) preoperatively and 9% reached the ceiling (highest possible score) postoperatively.ConclusionsKOOS, JR performs well in revision TKA patients with regard to internal consistency, external validity, responsiveness, and floor and ceiling effects. Our results support extending its use to revision TKA in both clinical and research settings.     

Comparison of Expectations and Outcomes in Rheumatoid Arthritis Versus Osteoarthritis Patients Undergoing Total Knee Arthroplasty

BackgroundWe hypothesized that patients undergoing primary total knee arthroplasty (TKA) for rheumatoid arthritis (RA) would have different preoperative expectations compared to osteoarthritis (OA) patients, and that postoperative satisfaction would correlate with specific postoperative pain and functional domains.MethodsThis is a retrospective cohort study of RA patients matched based on age, gender, American Society of Anesthesiologists score, and Charlson Comorbidity Index score 1:2 with OA patients (76 RA, 152 OA) who underwent primary TKA. The Hospital for Special Surgery Knee Replacement Expectations Survey, Visual Analogue Scale for Pain (VAS), Knee injury and Osteoarthritis Outcome Score (KOOS), and the Short Form-12 (SF-12) were compared at baseline and at 2 years postoperatively. Minimum clinically important differences (MCIDs) were calculated for KOOS and SF-12 subdomains.ResultsPreoperatively, RA patients had lower expectations, worse VAS Pain, and worse KOOS Pain, Symptoms, and Activities of Daily Living (P < .05). However, at 2 years, RA patients had significantly larger improvements in VAS (P = .01) and these 3 KOOS subdomains (P < .05), achieving comparable absolute scores to OA patients. Overall, 86.1% of RA and 87.1% of OA patients were either somewhat or very satisfied with their TKA. Patient satisfaction correlated with VAS Pain and KOOS outcome scores in both groups. RA and OA patients had high rates of achieving MCID in SF-12 physical component scores and all 5 KOOS subdomains. A higher proportion of RA patients achieved MCID in KOOS Symptoms (98.4% vs 77.2%, P < .001).ConclusionRA patients had lower baseline expectations compared to OA patients. However, RA patients had greater improvements in KOOS and SF-12 subdomains, and there was no difference in satisfaction compared to OA patients after TKA.     

The effect of a 12 week prehabilitation program on pain and function for patients undergoing total knee arthroplasty: A prospective controlled study

BackgroundThe concept of preparing the body before a stressful event, such as surgery, has been termed “prehabilitation” (preoperative physiotherapy and exercise programs). Prehabilitation programs for people awaiting total knee arthroplasty (TKA) have positive effects on patients health status and may also lead to better postoperative outcomes.AimThe purpose of this study was to examine effect of a prehabilitation program on knee pain, functional ability among patients with knee osteoarthritis after TKA surgery.Study DesignA Prospective Controlled Study.Patients and MethodsSubjects enrolled in this prospective controlled study who referred to our Orthopedics and Traumatology outpatient clinic between 2014 April–2015 May, had severe OA with pain not responsive to conservative treatment and scheduled for unilateral TKA. Subjects were assigned to a control or prehabilitation group. Patients of prehabilitation group were recruited from the orthopaedic waiting lists for primary unilateral TKA. Partipicants in the prehabilitation group were prescribed a training program that consisted of education and home-based exercise 12 weeks before the operation. After the TKA, all subjects partipicated in the same postoperative rehabilitation protocol. Evaluations were made before the surgery, with follow-up assessments at 3 and 6 months after surgery. Knee pain was assessed by the use of a 10-cm Visual Analog Scale (VAS) and function assesed by Knee injury and Osteoarthritis Outcome Score (KOOS) scale.ResultsA statistically significant improvement was observed in the values of VAS and all subsclaes of KOOS in both groups at third and sixth month compared to baseline. The intergroup comparison of the improvement (pre-post scores at sixth month) did not show any statistically significant diffeferences in VAS and KOOS scores.ConclusionOur results show that prehabilitation before TKA is not superior to surgical treatment alone but about 20% of the patients changed their operation decision. So it is important to be able to postpone this process especially in the early period.     

A Psycholgical Intervention Delivered by Automated Mobile Phone Messaging Stabilized Hip and Knee Function During the COVID-19 Pandemic: A Randomized Controlled Trial

BackgroundWe conducted a randomized controlled trial to evaluate the effectiveness of acceptance and commitment therapy (ACT) delivered via a mobile phone messaging robot to patients who had their total hip arthroplasty or total knee arthroplasty procedures postponed due to the COVID-19 pandemic.MethodsNinety patients scheduled for total hip arthroplasty or total knee arthroplasty who experienced surgical delay due to the COVID-19 pandemic were randomized to the ACT group, receiving 14 days of twice daily automated mobile phone messages, or the control group, who received no messages. Minimal clinically important differences (MCIDs) in preintervention and postintervention patient-reported outcome measures were utilized to evaluate the intervention.ResultsThirty-eight percent of ACT group participants improved and achieved MCID on the Patient-Reported Outcome Measure Information System Physical Health compared to 17.5% in the control group (P = .038; number needed to treat [NNT] 5). For the joint-specific Hip Disability and Osteoarthritis Outcome Score Joint Replacement and Knee Disability and Osteoarthritis Outcome Score Joint Replacement (KOOS JR), 24% of the ACT group achieved MCID compared to 2.5% in the control group (P = .004; NNT 5). An improvement in the KOOS JR was found in 29% of the ACT group compared to 4.2% in the control group (P = .028; NNT 5). Fourteen percent of the ACT group participants experienced a clinical important decline in the KOOS JR compared to 41.7% in the control group (P = .027; NNT 4).ConclusionA psychological intervention delivered via a text messaging robot improved physical function and prevented decline in patient-reported outcome measures in patients who experienced an unexpected surgical delay during the COVID-19 pandemic.Level of Evidence1.     

Patient Acceptable Symptom State for the Forgotten Joint Score in Primary Total Knee Arthroplasty

BackgroundIn order to better understand the clinical benefits of total knee arthroplasty (TKA) and improve the interpretability of the Forgotten Joint Score (FJS-12), the establishment of a meaningful change in score is necessary. The purpose of this study is to determine the threshold of the FJS-12 for detecting the patient acceptable symptom state (PASS) following primary TKA.MethodsWe retrospectively reviewed all patients who underwent elective, primary TKA and answered both the FJS-12 and the Knee Injury Osteoarthritis Outcome Survey, Joint Replacement KOOS, JR surveys 1-year postoperatively. The questionnaires were administered via a web-based electronic application. KOOS, JR score was used as the anchor. The anchor for PASS calculation should relate pain, physical function, and patient satisfaction. Two statistical methods were employed: (1) the receiver operating characteristic (ROC) curve point; (2) 75^th percentile of the cumulative percentage curve of patients who had the KOOS, JR score difference larger than the cut-off value.ResultsThis study included 457 patients. The mean 1-year FJS-12 score was 42.6 ± 27.8. The mean 1-year KOOS, JR score was 68.0 ± 17.2. A high positive correlation between FJS-12 and KOOS, JR was found (r = 0.72, P < .001) making the KOOS, JR a valid external anchor. The threshold score of the FJS-12 which maximized the sensitivity and specificity for detecting a PASS was 33.3 (AUC = 0.78, 95% CI [0.74, 0.83]). The cut-off value computed with the 75^th percentile approach was 77.1 (95% CI [73.9, 81.5]).ConclusionThe PASS threshold for the FJS-12 was 33.3 and 77.1 at 1-year follow-up after primary TKA using the receiver operating characteristic (ROC) curve and 75^th percentile approaches, respectively. These values can be used to assess the successful achievement of a forgotten joint.Level III EvidenceRetrospective Cohort Study.     

Computer-Assisted Kinematic and Mechanical Axis Total Knee Arthroplasty: A Prospective Randomized Controlled Trial of Bilateral Simultaneous Surgery

BackgroundRandomized controlled trials of kinematic alignment (KA) and mechanical alignment (MA) in primary total knee arthroplasty (TKA) have to date demonstrated at least equivalence of KA in terms of clinical outcomes. No trial of bilateral TKA has been conducted so patient preference for one technique over the other is unknown.MethodsForty-one participants underwent computer-assisted bilateral TKA. The outcome measures were as follows: (1) joint range of motion and functional scores including the KOOS, the KOOS JR, Oxford Knee Score, and the Forgotten Joint Score at a minimum of 2 years; (2) preference and perception of limb symmetry; (3) intraoperative alignment data; (4) release and gap balance data; and (5) postoperative radiographic joint angles.ResultsThere were no significant differences with respect to flexion range (P = .970) or functional scores (mean KOOS, P = .941; KOOS JR, P = .685; Oxford Knee Score, P = .578; FJS, P = .542). Significantly more participants who favored one knee preferred their KA TKA (P = .03); however, half of the patients had no preference and the overall numbers were small. Only 3 participants perceived any limb asymmetry (P < .001). More releases were required in the MA group (P = .018). Standing hip-knee-ankle angle means and frequency distributions were similar (P = .097 and P = .097, respectively).ConclusionClinical outcomes were equivalent at 2 years. Significantly more participants preferred their KA joint. Fewer releases were required using a KA technique. Participants were visually insensitive to modest hip-knee-ankle angle asymmetry.Level of EvidenceLevel 1.     

Survival and Outcomes of 1.5-Stage vs 2-Stage Exchange Total Knee Arthroplasty Following Prosthetic Joint Infection

BackgroundTraditional management of prosthetic joint infection following total knee arthroplasty (TKA) consists of a 2-stage approach. However, 1.5-stage exchange has seen preliminary success, whereby metal femoral and all-polyethylene tibia components are placed without intention for subsequent second stage. We sought to examine all patients who underwent a 1.5-stage exchange TKA at a single institution compared to historical 2-stage controls. We assessed the following: (1) infection-free survivorship and risk factors for reinfection; (2) 1-year surgical/medical outcomes; (3) patient-reported outcomes (ie, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement [KOOS JR]); and (4) radiographic outcomes.MethodsWe reviewed all patients undergoing a 1.5-stage (between 2015 and 2019) and 2-stage exchange TKA (between 2011 and 2016) at a single institution. A total of 162 knees were included (1.5-stage: 114; 2-stage: 48) with mean clinical follow-up of 2.6 years. KOOS JR scores and radiographic outcomes were evaluated at last clinical follow-up.ResultsThe 1.5-stage exchange TKA resulted in a 10.1% difference in infection-free survival (85.1% vs 75.0%, P = .158), compared to 2-stage exchange. Prior prosthetic joint infection was found to be an independent risk factor for reinfection (P = .030). Overall, postoperative complications were lower among 1.5-stage exchanges (8.8% vs 31.3%, P < .001). KOOS JR scores improved more from baseline among 1.5-staged (Δ24.7 vs Δ16.6, P < .001). Radiographic review did not demonstrate any progressive radiolucent lines, subsidences, or failures in either group.ConclusionA 1.5-stage exchange TKA is an effective alternative to the traditional 2-stage protocols with noninferior infection eradication and absence of radiographic complications at over 2 years of mean follow-up.     

Impact of Perioperative Pain Control on Knee Range of Motion and Development of Arthrofibrosis Following Primary Total Knee Arthroplasty

BackgroundInadequate pain control following total knee arthroplasty (TKA) has been postulated to negatively impact knee range of motion (ROM). We sought to determine the association between perioperative pain levels and knee ROM at 3-month follow-up or need for manipulation under anesthesia (MUA).MethodsWe retrospectively reviewed 2243 primary TKAs performed from 2002 to 2019 at a single academic center using an institutional total joint registry. Mean age was 68, mean body mass index was 32.8, and 59% were female. Knee ROM was measured preoperatively and 3 months postoperatively. Change in knee ROM, rates of soft tissue contracture, and MUA were assessed in relation to in-hospital 10-point pain visual analog scale (VAS) measurements.ResultsOverall, 44% had improved ROM at 3-month follow-up, 29% had no change in ROM, and 27% had worsened ROM. There was no significant difference in mean VAS scores of patients with improved, unchanged, or worsened ROM postoperatively (3.0 vs 2.8 vs 3.0; P = .068). There was no significant difference in mean VAS scores of patients who developed a soft tissue contracture or required MUA vs those who did not develop these complications (2.7 vs 2.9; P = .24). Similarly, no significant relationship with these outcomes was identified when maximum and discharge VAS scores were analyzed.ConclusionComparable ROM and rates of MUA based on in-hospital pain levels were observed in this large series of primary TKA patients. While significant early pain may limit participation in ROM exercises initially, this does not appear to have a marked impact on ROM-related complications for most patients.Level of EvidenceIII, Therapeutic.     

Similar patient-reported outcomes and performance after total knee arthroplasty with or without patellar resurfacing: A randomized study of 74 patients with 6 years of follow-up

Background and purpose — Knee pain after total knee arthroplasty (TKA) is not uncommon. Patellar retention in TKA is one cause of postoperative knee pain, and may lead to secondary addition of a patellar component. Patellar resurfacing in TKA is controversial. Its use ranges from 2% to 90% worldwide. In this randomized study, we compared the outcome after patellar resurfacing and after no resurfacing. Patients and methods — We performed a prospective, randomized study of 74 patients with primary osteoarthritis who underwent a Triathlon CR TKA. The patients were randomized to either patellar resurfacing or no resurfacing. They filled out the VAS pain score and KOOS questionnaires preoperatively, and VAS pain, KOOS, and patient satisfaction 3, 12, and 72 months postoperatively. Physical performance tests were performed preoperatively and 3 months postoperatively. Results — We found similar scores for VAS pain, patient satisfaction, and KOOS 5 subscales at 3, 12, and 72 months postoperatively in the 2 groups. Physical performance tests 3 months postoperatively were also similar in the 2 groups. No secondary resurfacing was performed in the group with no resurfacing during the first 72 months Interpretation — Patellar resurfacing in primary Triathlon CR TKA is of no advantage regarding pain, physical performance, KOOS 5 subscales, or patient satisfaction compared to no resurfacing. None of the patients were reoperated with secondary addition of a patellar component within 6 years. According to these results, routine patellar resurfacing in primary Triathlon TKA appears to be unnecessary.     

The first knee prosthesis to go through beyond compliance: A new standard for the safe introduction of orthopaedic implants

IntroductionBeyond Compliance (BC) was introduced in 2012 to improve the monitoring and regulation of new medical devices and techniques, ensuring patient safety whilst promoting innovation through an evidence based appraisal of devices during their introduction. This study reports the 2 year outcomes of the first Total Knee Replacement (TKR) implant to be assessed through the BC process.Methods100 consecutive patients undergoing primary knee arthroplasty were enrolled. All patients received a single radius cruciate retaining TKA (Unity, Corin), and the patella was resurfaced in all cases. Patients were followed up at 6 weeks, 3, 6, 12 and 24 months post operatively. Pre-and post-operative range of movement (ROM) as well as outcome scores including OKS, KOOS, EQ5D index and EQ5D VAS were recorded.Results100 patients with a mean age 73.6 (SD = 8.7) were included. 2 patients died during the follow-up period due to unrelated reasons. Overall satisfaction rates were 96%. Complications included ongoing pain (5 patients), and a periprosthetic fracture (1 patient) nine months post-surgery (traumatic). No knees were revised during the follow-up period. Significant improvements were observed in all outcomes measures (OKS, KOOS, EQ5D, and EQ5D VAS). The mean added ROM was 13.2°.DiscussionThis knee prosthesis has been demonstrated to be safe and effective with excellent early outcomes. The careful regulated introduction of this device through BC has ensured patients safety while supporting innovation in knee arthroplasty. The success of BC requires surgeons to insist industry fully engage with the process for all new devices or techniques.     

Lower function,quality of life,and survival rate after total knee arthroplasty for posttraumatic arthritis than for primary arthritis

Background and purpose — Total knee arthroplasty (TKA) for treatment of end-stage posttraumatic arthritis (PTA) has specific technical difficulties and complications. We compared clinical outcome, postoperative quality of life (QOL), and survivorship after TKA done for PTA with those after TKA performed for primary arthritis (PA).

Patients and methods — We retrospectively reviewed patients who were operated on at our institution for PTA between 1998 and 2005 (33 knees), and compared them to a matched group of patients who were operated on for PA during the same period (407 knees). Clinical outcomes and postoperative QOL were compared in the 2 groups using Knee Society score (KSS), range of motion (ROM) of the knee, and the knee osteoarthritis outcomes score (KOOS). Implant survival rate was calculated using Kaplan-Meier analysis.

Results — At a mean follow-up of 11 (5–15) years, KSS knee increased from mean 39 (SD 18) to 87 (SD 16) in the PA group (p = 0.003), and from 31 (SD 11) to 77 (SD 15) in the PTA group (p = 0.003). KSS function increased from 55 (12) to 89 (25) in the PA group (p = 0.008) and from 44 (SD 14) to 81 (SD 10) in the PTA group (p = 0.008). Postoperative ROM also improved in both groups, from 83° to 108° in the PTA group (p < 0.001) as opposed to 116° to 127° in the PA group (p = 0.001), with lower results in the PTA group (p < 0.001). KOOS was lower in the PTA group (p < 0.001). The survival rate of TKA at 10 years with an endpoint defined as “any surgery on the operated knee” showed better results in the PA group (99%, CI: 98–100 vs. 79%, CI: 69–89; p < 0.001).

Interpretation — Patients and surgeons should be aware that clinical outcome and implant survival after TKA for PTA are lower than after TKA done for PA     

A Single Surgeon Series Comparing the Outcomes of a Cruciate Retaining and Medially Stabilized Total Knee Arthroplasty Using Kinematic Alignment Principles

BackgroundTotal knee arthroplasty (TKA) designs are developed to optimize kinematics and improve patient satisfaction. The cruciate retaining (CR) and medially stabilized (MS) TKA designs have reported good mid-term follow-up outcomes. However, reasons for consistently high rates of patient dissatisfaction following a TKA remain poorly understood. To further investigate this, we compared the short-term functional outcomes and quality of life, using patient-reported outcome measures (PROMs) and range of motion (ROM), between a CR and MS TKA.MethodsA prospective comparison was made between 2 groups (44 CR-TKAs vs 46 MS-TKAs). The Knee Injury and Osteoarthritis Outcome Score (KOOS), KOOS-12, KOOS-Short form, KOOS-Joint Replacement, Oxford Knee Score, Western Ontario and McMaster Universities Osteoarthritis Index, UCLA Activity Scale, and EuroQuality of life – 5 Dimension were completed preoperatively and 1 year postoperatively. The Forgotten Joint Score (FJS) and Visual Analogue Scale-Satisfaction were completed at 1 year postoperatively. ROM was collected preoperatively and 1 year postoperatively.ResultsPatients who underwent an MS-TKA scored significantly better than the CR-TKA on the FJS (MS = 79.87, CR = 63.8, P = .005), the KOOS-12 Quality of Life subscale (MS = 82.8, CR = 74.4, P = .43), and the KOOS Quality of Life subscale (MS = 82.8, CR = 74.6, P = .44). There was no difference between the groups in all assessed PROMs or ROM, preoperatively and 1 year postoperatively.ConclusionPatients who underwent the MS-TKA scored significantly better on the FJS and the quality of life subscale of the KOOS and KOOS-12 than those who underwent a CR-TKA. All other assessed PROMs and ROM were comparable between the 2 groups and demonstrated that both implants facilitated symptom relief and improved daily function at 1 year postoperatively. These findings suggest that at short-term follow-up, the MS device is more likely to allow a patient to “forget” that a joint has been replaced and restore their quality of life. Long-term assessment of MS-TKA design outcomes in larger cohorts is recommended.     

Functional versus patient-reported outcome of the bicruciate and the standard condylar-stabilizing total knee arthroplasty

Introduction

The purpose of this retrospective comparative analysis in patients undergoing primary total knee arthroplasty (TKA) was to evaluate whether different TKA implant design would influence patient-rated outcomes, functioning, and range of motion (ROM). A secondary purpose of this study was to test for relationships between the patient-rated outcomes and the passive ROM.

Materials and methods

Thirty-one patients who had a primary bicruciate stabilized TKA performed between May 2010 and November 2012 were retrospectively reviewed and compared with a cohort of 30 patients who had condylar-stabilizing TKA during the same period.

Results

No significant differences were observed between the two groups with respect to preoperative demographic characteristics, ROM and radiographic knee alignment. At a mean follow-up of 37 months (SD 7), the Triathlon group had higher mean Knee Injury and Osteoarthritis Outcome Score (KOOS) score in all subscales and a higher Knee Society Score (KSS) score than the Journey group. This difference was statistically significant for the KOOS subscales of pain (p = 0.0099) and activities of daily living (ADL) (p = 0.0003), as well as the KSS score (p = 0.03846). The ROM was significantly higher in the Journey group when compared to the Triathlon group (p = 0.0013). No significant correlation was observed between the ROM and KOOS pain, QOL and ADL subscores and KSS score.

Conclusions

Postoperative knee ROM and patient perception of knee function after primary TKA can be affected by the different prosthetic designs. However, functionality afforded by the bicruciate TKA is not equivalent to patient satisfaction.

Level of evidence

III.

     

Postoperative Anteroposterior Laxity Influences Subjective Outcome After Total Knee Arthroplasty

Background

We hypothesized that postoperative anteroposterior (AP) stability of the knee correlates with patient-reported clinical outcome and knee function after total knee arthroplasty (TKA).

Can Machine Learning Methods Produce Accurate and Easy-to-Use Preoperative Prediction Models of One-Year Improvements in Pain and Functioning After Knee Arthroplasty?

BackgroundApproximately 15%-20% of total knee arthroplasty (TKA) patients do not experience clinically meaningful improvements. We sought to compare the accuracy and parsimony of several machine learning strategies for developing predictive models of failing to experience minimal clinically important differences in patient-reported outcome measures (PROMs) 1 year after TKA.MethodsPatients (N = 587) in 3 large Veteran Health Administration facilities completed PROMs before and 1 year after TKA (92% follow-up). Preoperative PROMs and electronic health record data were used to develop and validate models to predict failing to experience at least a minimal clinically important difference in Knee Injury and Osteoarthritis Outcome Score (KOOS) Total, KOOS JR, and KOOS subscales (Pain, Symptoms, Activities of Daily Living, Quality of Life, and recreation). Several machine learning strategies were used for model development. Ten-fold cross-validation and bootstrapping were used to produce measures of overall accuracy (C-statistic, Brier Score). The sensitivity and specificity of various predicted probability cut-points were examined.ResultsThe most accurate models produced were for the Activities of Daily Living, Pain, Symptoms, and Quality of Life subscales of the KOOS (C-statistics 0.76, 0.72, 0.72, and 0.71, respectively). Strategies varied substantially in terms of the numbers of inputs required to achieve similar accuracy, with none being superior for all outcomes.ConclusionModels produced in this project provide estimates of patient-specific improvements in major outcomes 1 year after TKA. Integrating these models into clinical decision support, informed consent and shared decision making could improve patient selection, education, and satisfaction.Level of EvidenceLevel III, diagnostic study.     

A One-Question Patient-Reported Outcome Measure Is Comparable to Multiple-Question Measures in Total Knee Arthroplasty Patients

BackgroundPatient-reported outcome measures (PROMs) are important for tracking outcomes following total knee arthroplasty (TKA) but can be limited by time constraints and patient compliance. We sought to evaluate the utility of the one-question, modified single assessment numerical evaluation (M-SANE) score in TKA patients compared to legacy PROMs.MethodsPatients undergoing TKA completed the Patient-Reported Outcomes Measurement Information System-10 (PROMIS-10), the Knee Disability and Osteoarthritis Outcomes Score Junior (KOOS Jr), and M-SANE (modified-SANE) assessments both preoperatively and postoperatively. The M-SANE score asked patients to rate their native or prosthetic knee on a scale from 0 to 10, with 10 being the best function. M-SANE validity was determined by the Spearman’s correlation between the collected PROMs and the Bland-Altman plots. PROM responsiveness was assessed using the standardized response mean.ResultsIn total, 217 patients completed PROMs preoperatively and at 1 year postoperatively. Floor and ceiling effects of the M-SANE were higher than other PROMs but still relatively low (4%-11%). There was a moderate to strong correlation at nearly all time points between the M-SANE and KOOS Jr (ρ = 0.44-0.78, P < .001). There was a weak correlation between the M-SANE and PROMIS physical component summary at the preoperative evaluation (ρ = 0.28) but a strong correlation at 1-year follow up (0.65, P < .001). The long-term responsiveness of the M-SANE to TKA (standardized response mean [SRM] = 0.98, 95% confidence interval [CI] 0.80-1.17) was comparable to both the KOOS Jr (SRM = 1.19, 95% CI 1.00-1.38) and PROMIS physical component summary (SRM = 0.82, 95% CI 0.74-0.91). Bland-Altman plots demonstrated that the M-SANE and KOOS Jr capture combined knee pain and functionality differently.ConclusionThe M-SANE score was comparable to validated multiple-question PROMs in TKA patients. The demonstrated validity of the M-SANE, as well as its comparable responsiveness to more lengthy PROMs, highlights its use as a one-question PROM for assessment of patient undergoing TKA.     

Development and Validation of Crosswalks Between the Western Ontario & McMaster Universities Osteoarthritis Index and Hip Disability and Osteoarthritis Outcome Score Joint Replacement/Knee Injury and Osteoarthritis Outcome Score Joint Replacement

BackgroundThe wide variety of patient-reported outcome measures used to assess outcomes following total joint arthroplasty can present a substantial methodological obstacle when attempting to compare information across studies or between institutions. A simple solution is to create crosswalks that reliably convert scores between patient-reported outcome measures. Our goal is to create and validate crosswalks between the commonly used Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) and short-form versions of the Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS JR)/Knee Injury and Osteoarthritis Outcome Score (KOOS JR.).MethodsPatients in our joint replacement registry were included if they underwent primary total hip arthroplasty (n = 4649) or total knee arthroplasty (n = 3750) for osteoarthritis between May 2007 and February 2012. We used their preoperative and 2-year postoperative HOOS scores (n = 6351) or KOOS scores (n = 4688) to generate the patients’ WOMAC and HOOS JR/KOOS JR scores. The equipercentile equating method was applied to create 10 crosswalks: HOOS JR/KOOS JR to WOMAC Total (WOMAC-T), and WOMAC-T, WOMAC Pain (WOMAC-P), WOMAC Stiffness (WOMAC-S), and WOMAC Function (WOMAC-F) to HOOS JR/KOOS JR. Crosswalk validity was assessed by comparing actual and derived scores using Spearman’s rank correlation coefficients in a bootstrapped cohort.ResultsAll 10 crosswalks showed strong positive correlations ranging from 0.846 (WOMAC-S to KOOS JR) to 0.981 (HOOS JR to WOMAC-T).ConclusionWe created and validated 10 crosswalks between WOMAC and HOOS JR/KOOS JR. We recommend using the crosswalks between WOMAC-T and HOOS JR/KOOS JR when possible, as they demonstrated the highest correlation. WOMAC-F or WOMAC-P should be used in favor of WOMAC-S if only subscores are available. The HOOS JR/KOOS JR should only be converted to a WOMAC-T.Level of EvidenceLevel III.