Activity levels and return to work following total knee arthroplasty in patients under 65 years of age

What recovery domains are important following a total knee replacement? A qualitative, interview-based study

OBJECTIVES

To explore people's views of recovery from total knee replacement (TKR) and which recovery domains they felt were important.

DESIGN

Semi-structured interviews exploring the views of individuals about to undergo or who have undergone TKR. A constant-comparative approach with thematic analysis was used to identify themes. The process of sampling, collecting data and analysis were continuous and iterative throughout the study, with interviews ceasing once thematic saturation was achieved.

SETTING

Tertiary care centre.

PARTICIPANTS

A purposive sample was used to account for variables including pre, early or late postoperative status.

RESULTS

12 participants were interviewed, 4 who were preoperative, 4 early postoperative and 4 late postoperative. Themes of pain, function, fear of complications, awareness of the artificial knee joint and return to work were identified. Subthemes of balancing acute and chronic pain were identified.

CONCLUSIONS

The results of this interview-based study identify pain and function, in particular mobility, that were universally important to those undergoing TKR. Surgeons should consider exploring these domains when taking informed consent to enhance shared decision-making. Researchers should consider these recovery domains when designing interventional studies.

Clinical Outcomes and Return-to-Sport Rates following Fragment Fixation Using Hydroxyapatite/Poly-L-Lactate Acid Threaded Pins for Knee Osteochondritis Dissecans: A Case Series

Osteochondritis dissecans (OCD) of the knee is an uncommon injury in young active patients. There is currently a lack of knowledge regarding clinical outcomes and return-to-sport rates after fragment fixation surgery using hydroxy appetite poly-L-lactic acid (HA/PLLA) threaded pins for knee OCD among athletes. Our purpose was to investigate the clinical outcomes and return-to-sport rates following osteochondral fragment fixation using HA/PLLA pins for the treatment of knee OCD lesions among athletes. A total of 45 patients were retrospectively reviewed. In total, 31 patients were excluded, and 14 patients were included. Pre- and postoperative patient-reported outcome scores (PROSs), including the International Knee Documentation Committee (IKDC) score and Knee Injury and Osteoarthritis Outcome Scale (KOOS), were compared. In addition, patients were categorized into four groups according to postoperative sports status: higher, same, lower than preinjury, or unable to return to sports. The mean age was 14.4 years (SD 1.67). All patients were male. All PROSs significantly improved at 6, 12, and 24 months postsurgery compared to presurgery. 50% of the patients returned to sports at the same or higher level after surgery. Fragment fixation using HA/PLLA pins leads to favorable clinical outcome scores and high return-to-sport rates in the treatment of athletes with knee OCD.

The CCJR® Gerard A. Engh Excellence in Knee Research Award: Remote Monitoring of Sleep Disturbance Following Total Knee Arthroplasty: A Cautionary Note

BACKGROUND

Sleep disturbances are common after total knee arthroplasty (TKA). Despite the rising popularity of wearables to track sleep, little evidence exists in the arthroplasty literature regarding their efficacy. We aimed to correlate validated wearable sleep metrics with patient-reported sleep quality following TKA.

METHODS

Patients undergoing primary TKA were consecutively enrolled. Patients used a wearable device preoperatively and 90 days postoperatively to track five previously-validated measures of sleep. Each month, they rated their sleep quality. Wearable sleep data was correlated with patient-reported sleep quality using a point biserial correlation test. Categorical data were compared using Chi-square tests. A total of 110 patients were included.

RESULTS

Preoperatively, 20.8% of patients reported "fairly bad" or "very bad" sleep; this increased to 44.4% 30 days postoperatively, then decreased to 26.5% 60 days postoperatively, and to 20.2% 90 days postoperatively. At 30 days postoperatively, time in bed, time asleep, and minutes of rapid eye movement sleep weakly correlated with patient-reported sleep quality (correlations 0.356, 0.345, and 0.345, respectively; P < .001). Sleep quality did not correlate with any wearable metric collected 60 or 90 days postoperatively.

CONCLUSIONS

Patient-reported sleep quality following TKA initially worsened postoperatively, then improved to preoperative levels by 90 days. Time in bed, time asleep, and rapid eye movement sleep minutes only weakly correlated with patient-reported sleep quality at 30 days; no other correlations were detected. Surgeons that utilize remote monitoring following TKA should be aware that surrogate measures generated from these devices may correlate weakly, if at all, with the patient-reported outcome of the parameter being studied.

Return to Work after Primary Total Knee Arthroplasty: The First Polish Pilot Retrospective Study

(1) Background: Total knee arthroplasty (TKA) performed on working-age patients significantly affects the participation of such patients in social life. A retrospective study was conducted to determine the return to work (RTW) rate after TKA. The goal of this study was to provide reference data for the Polish population and identify the factors impacting patients' decisions to return to or resign from work, relative to their functional performance. (2) Methods: This retrospective study involved 48 patients. An interview related to RTW was carried out to identify the factors impacting a patient's decision to return to or resign from work. Functional performance was assessed using the Knee Outcome Survey-Activities of Daily Living (KOS-ADL) scale. (3) Results: Before TKA, 15 individuals (31.25%) qualified for the study did not work and were receiving welfare benefits. After the surgery, 23 individuals (47.9% of those working prior to TKA) did not return to work. The number of those who did not work after TKA increased to 38 (79.17%), which was a significant change. The mean level of functional performance after TKA assessed using KOS-ADL was 75.89. (4) Conclusions: The findings show that the rate of RTW after TKA in Poland is significantly lower than that in other countries. The reasons for this situation, as shown in the study, may be related to the lack of an occupational rehabilitation system, resulting in a paucity of information about the possibility to return to work and about opportunities for retraining.

Discrepancies in Sagittal Alignment of the Lower Extremity Among Different Brands of Robotic Total Knee Arthroplasty Systems

BACKGROUND

There is an increasing number of different brands of robotic total knee arthroplasty (TKA) systems. Most robotic TKA systems share the same coronal alignment, while the definitions of sagittal alignment vary. The purpose of this study was to investigate whether these discrepancies impact the sagittal alignment of the lower extremity.

METHODS

A total of 72 lower extremity computed tomography scans were included in our study, and 3-dimensional models were obtained using software. A total of 7 brands of robotic TKA systems were included in the study. The lower extremity axes were defined based on the surgical guide for each implant. We also set the intramedullary axis as a reference to evaluate the discrepancies in sagittal alignment of each brand of robotic system.

RESULTS

On the femoral side, the axis definition was the same for all 7 robotic TKA systems. The robotic TKA axes showed a 2.41° (1.58°, 3.38°) deviation from the intramedullary axis. On the tibial side, the 7 robots had different axis definitions. The tibial mechanical axis of 6 of the TKA systems was more flexed than that of the intramedullary axis, which means the posterior tibial slope was decreased while the tibial mechanical axis of the remaining system was more extended.

CONCLUSIONS

The sagittal alignment of the lower extremity for 7 different brands of robotic TKA systems differed from each other and all deviated from the intramedullary axis. Surgeons should be aware of this discrepancy when using different brands of robotic TKA systems to avoid unexpected sagittal alignment and corresponding adverse clinical outcomes.

LEVEL OF EVIDENCE

Level IV, Therapeutic Study.

Return to work following revision knee arthroplasty in patients under 65 years of age: A retrospective study

Background

Little is known about employment following revision total knee arthroplasty (RTKA). This study aims to describe factors associated with returning to employment in patients of working age who underwent RTKA surgery.

Methods

We performed a retrospective assessment of all patients aged ≤65 who underwent RTKA at our NHS institution between 2006 and 2020. All indications and revision procedures were included. Pre-operative demographics, indication for surgery and Oxford Knee Scores (OKS) were recorded. Postal questionnaires were sent to patients including patient reported outcome measures and a departmental questionnaire asking patients about employment status pre- and post-operatively.

Results

132 procedures were performed in 113 patients. Median follow up was 5.5 years (2.4-9.0). Mean age was 58 (5.8) and 50% (57) were men. 62 patients undergoing 74 procedures responded to postal questionnaires and were included in the study. 53% (33) were employed prior to surgery and 61% (38) returned to work at a median of 12 weeks (3-150). Of the 24 who did not return to work, 7 reported intending to return to work. Those patients who returned to work had increased pre-operative OKS (16.9 vs 13.6) and mean improvement (16.5 vs 12.4).

Conclusion

This study is limited by small numbers and its observational nature. In this population the majority of patients who wished to return to work after RTKA were able to do so. This provides some reassurance when counselling patients. Prospective studies to better understand the factors that predict return to work will be important with increasing demands from surgery.

Return to work status of patients under 65 years of age with osteonecrosis of the femoral head after total hip arthroplasty

OBJECTIVE

This aimed to evaluate the status of return to work (RTW) in patients with osteonecrosis of the femoral head (ONFH) after total hip arthroplasty (THA).

METHODS

The baseline characteristics of all patients in this retrospective study were obtained from the hospital patient database. The relevant changes in patients' working conditions, as well as the numerical rating scale (NRS), Harris Hip Score (HHS), self-assessment of work ability, and Likert scale satisfaction assessment were obtained through video call follow-ups.

RESULTS

118 patients (response rate: 83%) were ultimately included in this study. The average length of time for the patients to stop working preoperatively was 20.7 weeks. Ninety-four patients (24 women and 70 men) who underwent THA had RTW status, with a mean RTW time of 21.0 weeks. Men had a significantly higher proportion of final RTW and a significantly faster RTW than women. Significant differences in smoking, drinking, cardiovascular diseases, changes in working levels, variations in the types of physical work, changes in working hours, and pain symptoms were observed between the RTW and Non-RTW populations. The patients with a positive RTW status had higher postoperative HHS scores, lower postoperative NRS scores, and higher self-assessment of work ability than patients who had a negative RTW status.

CONCLUSION

Ultimately, 80% of patients achieved RTW status. Drinking, sex, change in working level, variation in the type of physical work, change in working hours, post-surgery HHS score and self-assessment of work ability can serve as predictive factors for RTW.

Trajectory of chronic and neuropathic pain, anxiety and depressive symptoms and pain catastrophizing after total knee replacement. Results of a prospective, single-center study at a mean follow-up of 7.5 years

INTRODUCTION

A considerable number of patients are not satisfied after total knee replacement (TKR) because of persistent pain. This pain can also be neuropathic in origin. Both types of pain have a large impact on function and quality of life. Furthermore, the trajectory of anxiety and depressive symptoms and pain catastrophizing has rarely been studied after TKR surgery. The primary objective of this study was to define the trajectory of knee pain after primary TKR. The secondary objectives were to evaluate how neuropathic pain, anxiety and depressive symptoms and pain catastrophizing change over time.

METHODS

This prospective, single-center study included patients who underwent primary TKR for primary osteoarthritis between July 2011 and December 2012. Personal data (age, sex, body mass index, knee history, operated side, surgical approach, type of implant, operative time, and rehabilitation course) and the responses to seven questionnaires (Numerical pain rating scale, DN4-interview for neuropathic pain, Oxford Knee Scale, Hospital and Anxiety Depression Scale, Beck Depression Inventory, Patient Catastrophizing Scale and Brief Pain Inventory) were determined preoperatively, at 6 months postoperative and at a mean follow-up of 7.5 years.

RESULTS

Preoperatively, 129 patients (35 men, 94 women) filled out all the questionnaires. Subsequently, 32 patients were excluded because of incomplete responses at 6 months postoperative, 6 were excluded because they had undergone revision surgery, 11 patients were lost to follow-up and 5 patients had died. In the end, 65 patients were available for analysis (50% of the initial cohort) who were 74 years old on average at inclusion. Between the preoperative period and 6 months postoperative, pain (p<0.001), function (p<0.001), anxiety symptoms (p<0.001) and catastrophizing (p<0.001) had improved. Depressive symptoms did not change (p=0.63). Between 6 months postoperative and the latest follow-up, none of the parameters changed further (p>0.05). Of the 65 patients analyzed, 21% had chronic pain of undefined origin at 6 months postoperative and 26% had chronic pain at the end of follow-up, with 50% also having neuropathic pain. Preoperatively, 40% of the 65 patients had neuropathic pain, 30% at 6 months (p=0.27) and 18% at 7.5 years after TKR (p=0.01).

CONCLUSION

The number of patients who have chronic pain after TKR is considerable, especially since knee pain stabilized at 6 months postoperative. Early detection is vital to prevent the pain from becoming chronic, which makes it more difficult to treat. Half the patients with persistent pain also had neuropathic pain, which should be detected before surgery so the patients can be referred to a specialized pain management center. The presence of anxiety and depressive symptoms and pain catastrophizing is not a contraindication to TKR, but these patients should be referred to specialists for treatment before surgery.

LEVEL OF EVIDENCE

IV, prospective cohort study.

Cost-Effectiveness of Robot-Assisted Total Knee Arthroplasty: A Markov Decision Analysis

BACKGROUND

Robot-assisted total knee arthroplasty (rTKA) may improve clinical outcomes for patients who have end-stage osteoarthritis of the knee. However, the costs of rTKA are high, and there is a paucity of data evaluating the cost-effectiveness of rTKA. We aimed to analyze the cost per quality-adjusted life-year (QALY) of rTKA relative to manual TKA.

METHODS

A Markov decision analysis was performed using known parameters for costs, outcomes, implant survivorships, and mortalities. The cost-effectiveness of rTKA relative to manual TKA was assessed for end-stage knee osteoarthritis patients who had a mean age of 65 years (range, 27 to 94 years). The rTKA costs were calculated for a pay-per-use contract robot.

RESULTS

Using the Markov Model with an annual case volume of 500 patients and a mean age of 65 years, the overall health gain per patient was 13.34 QALYs after rTKA and 13.31 QALYs after manual TKA. This resulted in an overall gain in QALYs of 0.03 for each patient undergoing an rTKA compared with manual TKA and an incremental cost of $128,526 Singapore Dollars per QALY.

CONCLUSION

Robotic TKA is not a cost-effective alternative to conventional TKA using a pay-per-use contract robot.

Return to Sports and Return to Work After Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Return to work (RTW) and sports (RTS) are critical gauges to improvement among patients after total knee arthroplasty (TKA). This study aimed to determine rates, timelines, and prognostic factors associated with RTW and RTS outcomes after primary TKA.

METHODS

A systematic review was conducted on MEDLINE, Embase, and CENTRAL databases, with 44 studies meeting inclusion/exclusion criteria. The risk of bias was assessed using the Risk of Bias in Nonrandomized Studies of Interventions tool. Meta-analysis and pooled analysis were conducted when possible with forest plots to summarize odds ratios and associated 95% confidence intervals (CIs).

RESULTS

The pooled RTW rate across all studies was 65% (95% CI, 51%-77%), with rates varying significantly from 10% to 98%. The mean time to RTW was of 12.9 weeks (range, 5-42). A time point analysis showed increasing RTW rates with a maximum rate at 1 year of 90%. Increased age was associated with lower RTW rates (p < 0.001). The RTS rate ranged from 36% to 100%, with a pooled rate of 82% (95% CI, 72%-89%). The mean time to RTS was 20.1 weeks (range, 16-24). A wide range of reported recurrence rates was observed among different sports (subgroup differences, p ≤ 0.001). The RTS ranged from 43% to 98%, with a pooled proportion of 76% (95% CI, 59%-87%, I2 = 91%) for low-intensity sports, and from 0% to 55% for high-intensity sports, with a pooled proportion of 35% (95% CI, 20-52, I2 = 70%).

CONCLUSION

Most patients successfully return to sports and work after TKA, with rates of RTW increasing to 90% after 1 year. Such outcomes are heavily influenced by nonmodifiable (e.g., age) and modifiable (e.g., intensity of sports/employment) factors. Generally, young adults and patients with low-demand jobs can be reinitiated earlier, albeit with increasing restrictions with rising intensity. Providers should screen patients for desire to RTW and/or RTS after surgery and provide appropriate recommendations as part of necessary preoperative education and postoperative care.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Clinical evaluation of the first semi-active total knee arthroplasty assisting robot made in China: a retrospective propensity score-matched cohort study

OBJECTIVE

The precision of overall alignment and knee morphotype after robot-assisted total knee arthroplasty has been fully confirmed. This study aims to conduct a clinical evaluation of the first China-made semi-active total knee arthroplasty assisting robot.

METHODS

After a 1 : 2 propensity score matching, that is, a matched cohort study, patients were matched to the robot group (52 cases) and the conventional group (104 cases). The robot group received osteotomy according to preoperative planning, while the conventional group adopted preoperative planning based on the full-length radiograph and received conventional osteotomy. Perioperative clinical indicators, such as operation time, tourniquet time, hospitalization days, intraoperative bleeding, and hemoglobin level of the two groups were recorded; radiological indicators of postoperative prosthesis position, including hip-knee-ankle angle, frontal femoral component angle, frontal tibial component angle, lateral femoral component angle, and lateral tibial component angle were also recorded; deviations and outliers of the radiological indicators were calculated.

RESULTS

Compared with the conventional group, the operation time and tourniquet time of the robot group were longer, and the postoperative hemoglobin level decreased less, the differences were statistically significant; the lateral tibial component angle of the conventional group was 80.9°±3.6°, which was smaller than 86.7 °±2.3° of the robot group, the difference was statistically significant ( P <0.001); except for lateral femoral component angle, the absolute deviations of the radiological indicators in the robot group were significantly smaller than that in the conventional group ( P ≤0.001); the outliers of the radiological indicators in the robot group were significantly smaller than that in the conventional group with a statistical difference ( P <0.05).

CONCLUSION

Compared with the conventional group, the operation time of the robot group was relatively longer, but the perioperation blood loss was less. The robot group could better control the posterior inclination of the tibial prosthesis, and the absolute deviations and outliers of the prosthesis position were relatively smaller. There was no difference in short-term clinical score between the two groups.

Conversion Total Knee Arthroplasty after Failed Osteochondral Allograft Reconstruction: Similar Functional Performance with Lower Patient Satisfaction

BACKGROUND

This study presents surgical techniques used in conversion total knee arthroplasty (cTKA) following early failure of large osteochondral allograft joint replacement and compares postoperative patient reported outcomes measures (PROMs) and satisfaction scores with a contemporary primary total knee arthroplasty (pTKA) cohort.

METHODS

We retrospectively evaluated 25 consecutive cTKA patients (26 procedures) to define utilized surgical techniques, radiographic disease severity, preoperative and postoperative PROMs (visual analog scale (VAS) pain, knee injury and osteoarthritis outcome score for joint replacement (KOOS-JR), University of California Los Angeles (UCLA) Activity), expected improvement and postoperative satisfaction (5-point Likert), and reoperations in comparison with an age and body mass index (BMI) propensity matched cohort of 50 pTKA performed for osteoarthritis (52 procedures).

RESULTS

Revision components were used in 12 cTKA cases (46.1%), with 4 cases requiring augmentation (15.4%), and 3 cases utilizing varus-valgus constraint (11.5%). While no significant differences were noted in expectation level or in other PROMs, mean patient reported satisfaction was lower in the conversion group (4.4 +/- 1.1 vs 4.8 +/- 0.5 points, P=0.02). High cTKA satisfaction was associated with higher postoperative KOOS-JR (84.4 vs 64.2 points, P=0.01) and trend towards higher UCLA activity (6.9 vs 5.7 points, P=0.08). Four patients in each group underwent manipulation (15.3 vs 7.6%, P=0.42), and one primary TKA patient was treated for early postoperative infection (0 vs 1.9%, P=1.0).

CONCLUSION

Conversion TKA following failed biological replacement was associated with similar postoperative improvement as in pTKA. Lower patient reported cTKA satisfaction was associated with lower postoperative KOOS-JR scores.

Sleep Disturbances Following Total Knee Arthroplasty

BACKGROUND

Sleep disturbances are common after total knee arthroplasty (TKA), yet literature examining sleep and postoperative pain remains sparse. With the use of wearable devices, convenient objective remote sleep monitoring is now possible. We aimed to measure patient sleep following TKA using validated questionnaires and wearable devices to compare sleep patterns to pain scores 90 days postoperatively.

METHODS

Adult patients with body mass index < 45 undergoing unilateral primary TKA were enrolled. Patients wore a monitor, which tracked sleep duration and disturbances (getting up at least once during the night). They completed weekly Pittsburgh Sleep Quality Index (PSQI) questionnaires and visual analog scale (VAS) pain scores. Sleep patterns were compared with pain scores and sleep duration was compared with PSQI responses.

RESULTS

There were 110 patients included with 54.5% women; average age was 64 years (range, 43-80). VAS scores decreased postoperatively. PSQI overall sleep scores, sleep quantity, and sleep quality worsened for the first 30 days then improved past baseline levels by 90 days. Recorded sleep duration did not change, and recordings did not correlate at any point with VAS scores. PSQI overall score and sleep quantity did not correlate with VAS. At 30 days postoperatively, patients reporting "very bad" sleep had significantly worse VAS scores than those reporting "bad" sleep.

CONCLUSION

Patient-reported sleep quality (very bad sleep) correlated well with VAS pain score at 30 days, while sleep duration (monitored or patient-reported) did not correlate with any clinical measure and does not seem to be a useful metric in assessing TKA outcome.

Interactive Combinations Between Gait Speed and Physical Function at Acute Phase Can Predict the Physical Activity at 2 Years After Total Knee Arthroplasty Using Classification and Regression Tree Analysis

OBJECTIVE

To clarify the interactive combinations of various clinical factors associated with physical activity (PA) at 2 years after total knee arthroplasty (TKA) using classification and regression tree (CART) analysis.

DESIGN

A retrospective cohort study.

SETTING

A single university hospital.

PARTICIPANTS

286 patients who underwent TKA (N=286).

MAIN OUTCOME MEASURES

PA was assessed preoperatively, 3 weeks, and 2 years after TKA. Physical functions, namely, 10 m walking test (10MWT), timed Up and Go test, 1-leg standing time, isometric knee extension and flexion strength, knee joint stability, knee pain, femora-tibial angle, and the passive knee extension and flexion angle, were measured before surgery as a baseline and 3 weeks after TKA as acute phase. CART analysis was conducted to clarify the interactive combinations that accurately predict the PA at 2 years after TKA.

RESULTS

The results of CART analysis indicated that gait speed (≥1.05 m/s) at the acute phase after TKA was the primal predictor for the postoperative PA at 2 years. The highest postoperative PA at 2 years was determined by gait speed (≥1.05 m/s) and PA (>74.5) at the acute phase. The PA at baseline and at acute phase, as well as the body mass index were also selected as predictors of postoperative PA at 2 years.

CONCLUSION

The present study suggested that acquiring gait speed (≥1.05 m/s) and PA (>74.5) in the postoperative acute phase is the predictive of a high PA at 2 years after TKA.

Return to work and employment retention after uni-compartmental and total knee replacement: findings from the Clinical Outcomes in Arthroplasty study

BACKGROUND

Little is known about ability to work after unicompartmental knee replacement (UKR) and total knee replacement (TKR), especially in physically-demanding occupations. This study described rates of return-to-work (RTW) and ability to sustain work by job after arthroplasty.

METHOD

Participants from The Clinical Outcomes in Arthroplasty Study (COASt) aged 18-65 were eligible if they underwent UKR or TKR and had at least 5 years' follow-up post-operation. We posted a survey asking about pre-operative occupation, post-operative occupations and associated physical demands, and whether they had quit a job post-surgery due to difficulties with the operated knee (knee-related job loss (KRJL)). We fitted Cox Proportional Hazard Models to investigate the role of demanding physical activities on KRJL.

RESULTS

251 people (143 UKR, 108 TKR) returned a questionnaire, of whom 101 UKR and 57 TKR worked post-operatively. Rates of RTW were highest amongst those in managerial and professional or technical roles, whichever operation they received. RTW was poorest amongst those in elementary occupations. In associate professional/technical occupations, RTW rates were better amongst UKR recipients. Amongst participants who returned to work, 17 reported KRJL (8.5% UKR and 16.7% TKR). Respondents were more likely to have KRJL if their job involved carrying/lifting ≥10 kg (HR:4.81, 95%CI 1.55-14.93) or climbing >30 flights of stairs (HR:4.03, 95%CI 1.36-11.98).

CONCLUSIONS

Knee arthroplasty recipients working pre-operatively mostly RTW. RTW may be more difficult after TKR than UKR. Jobs which involve lifting and climbing stairs may be particularly challenging. Surgeons offering knee arthroplasty should counsel patients about workability as well as risk of revision.

High accuracy of a new robotically assisted technique for total knee arthroplasty: an in vivo study

PURPOSE

Over the last decade, robotic TKA gained popularity for improving the accuracy of implant positioning and reducing outliers in limb alignment comparing to conventional jig-based TKA. Hypothesis of this study was that this newly designed robotically assisted system will achieve a high level of accuracy for bone resection. Purpose of the study was to evaluate the accuracy of the system.

METHODS

For this study, 75 knees in 75 patients were operated using a new, robotic system (ROSA^® Knee System; Zimmer Biomet, Warsaw, IN) with a Posterior Stabilized Total Knee Arthroplasty (Persona^® Knee System). The planned, validated and measured angles and cuts for the distal and posterior femur, for the proximal tibia and for the final coronal alignment on long standing x-rays were compared.

RESULTS

A statistically significant difference was found only between the average planned and the average validated angle for femoral flexion, tibial coronal axis, medial and lateral cuts; the average difference was in any case below 1 mm or under 1 degree with SD < 1. No statistical difference was found between planned validated and measured cuts. Average difference between planned HKA and measured was 1.2 ± 1.1. No statistically significant difference was found.

CONCLUSIONS

The results of this study demonstrated that using this new surgical robot in total knee arthroplasty it is possible to perform accurate bone cuts and to achieve the planned angles and resections.

Gait-related self-efficacy is directly associated with daily step counts in individuals with knee osteoarthritis

BACKGROUND

In addition to physical factors, psychological factors such as self-efficacy (SE) reportedly affect physical activity (PA) levels in individuals with knee osteoarthritis (OA). However, the relationship between PA and SE for walking tasks in patients with knee OA remains unclear. The present study aimed to investigate the direct and indirect pathways of SE for walking tasks and the influence of previously reported factors on PA level in individuals with knee OA.

METHODS

A cross-sectional design was employed. Eighty-five individuals with knee OA were enrolled. The daily step count (Steps) was considered an objective level of PA. The SE for the walking task was assessed using a modified Gait Efficacy Scale (mGES). Data on gait speed (GS), the visual analog scale (VAS) score for knee pain, Kellgren-Lawrence (K-L) grade of radiographic severity of knee OA, age, and body mass index were collected. Path analysis was performed to investigate the direct and indirect effects of these variables on Steps.

RESULTS

After exclusion, 70 participants were included. The alternative model, which included Steps, mGES, GS, VAS, K-L grade, and age, showed a good fit. mGES and age had a direct effect on Steps (standardized path coefficients: 0.337 and -0.542, respectively), while the other variables had indirect effects.

CONCLUSIONS

The SE for walking tasks was directly associated with Steps representative of the PA level. This finding suggests that SE for the walking task may be important in improving PA levels in individuals with knee OA.

Sleep Disturbances and Disorders in Patients with Knee Osteoarthritis and Total Knee Arthroplasty

➤

There is increasing evidence that patient-reported outcomes following total knee arthroplasty (TKA) are associated with psychosocial factors and pain catastrophizing. Sleep disturbance, pain, and mental health have a complex interaction, which, if unrecognized, can be associated with impaired patient-reported outcomes and dissatisfaction following TKA.

➤

The gold standard of objective sleep assessment is polysomnography, which is not feasible to use routinely for TKA patients. Wearable devices are a validated and less costly alternative.

➤

Subjective sleep measures, such as the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, or Patient-Reported Outcomes Measurement Information System (PROMIS) computerized adaptive test sleep domains, are simple to administer and provide additional insight into sleep disturbance. Although objective and subjective measures do not correlate precisely, they can be informative together.

➤

Sleep disturbances in the elderly population are common and multifactorial in etiology, stemming from the interplay of sleep disorders, medication side effects, and pain. Commonly prescribed medications following TKA as well as postoperative pain can exacerbate underlying sleep disturbances.

➤

Obstructive sleep apnea (OSA) is prevalent in patients seeking TKA. In the setting of OSA, postoperative opioids can cause respiratory depression, resulting in consequences as severe as death. A standardized multimodal pain protocol including anti-inflammatories and gamma-aminobutyric acid (GABA) analogues may allow for decreased reliance on opioids for pain control.

➤

Surgeons should reassure patients that postoperative sleep disturbance is common and transient, collaborate with the patient's primary care doctor to address sleep disturbance, and avoid prescription of pharmaceutical sleep aids.

Return to Work after Primary Total Knee Arthroplasty under the Age of 65 Years: A Systematic Review

A growing number of patients undergoing total knee arthroplasty (TKA) is at working age and need to return to work (RTW) after surgery. The aim of this systematic review is to give an overview of the literature regarding RTW after TKA and beneficial and limiting factors influencing this process. A systematic search in four electronic databases was conducted in November 2019 to identify studies describing RTW after primary TKA in patients aged 65 years or younger. Study characteristics and data on work status before and after surgery were extracted. All studies were assessed for risk of bias. Fourteen studies published between 2009 and 2019 were included in this review, accounting for a total of 3,073 patients. The percentage of patients working after TKA ranged from 36 to 89%, and the fraction of patients working before and returning to work after surgery ranged from 40 to 98%. Mean time of RTW ranged from 7.7 to 16.6 weeks. Most important factors associated with a slower or no RTW were a more physical nature of employment and preoperative absence from work. The majority of patients undergoing TKA returned to work postoperatively. However, comparison between studies is seriously hampered by the wide variation regarding the definition and timeframe used to measure the work status. Therefore, standardized outcome measures for studies investigating RTW after TKA are warranted. We identify this review as level-I evidence (systematic review of level-I and level-II studies).

A well performing medial fixed bearing UKA with promising survivorship at 15 years

BACKGROUND

Unicompartmental knee arthroplasty (UKA) accounts for 10% of knee arthroplasty procedures in Europe. Fixed bearing UKA designs have shown favorable survivorship in registries when compared with mobile bearings. This study analyses long-term follow-up of patients with a medial fixed bearing metal backed tibial UKA and reports 15 years survivorship and clinical outcomes.

METHODS

Data were collected prospectively for 148 medial unicompartmental fixed bearing metal backed UKAs implanted in 148 patients in two high volumes knee arthroplasty centers between January 2005 and December 2007. The indication was osteoarthritis in all but 2 patients. Patients' reported outcome scores were documented at last follow up. The mean patient age at time of surgery was 65 years.

RESULTS

At final follow up, outcome and survivorship data were collected for 124 medial fixed bearing UKAs. Thirteen patients underwent revision; average time to revision was 77 months (SD 35.31). The Kaplan-Meier analysis demonstrated a survivorship of 97.65% at 69 months and of 89,52%. at 120 months and 173 months of follow-up. When revisions for infection were excluded, the survivorship of the implant was 90.3% at the last of follow up. The mean OKS was 43.02 (SD 5.1) at the last follow-up, and the mean FJS was 77.6 (SD 6.9).

CONCLUSION

This Medial fixed bearing metal backed UKA demonstrates promising long-term survivorship and patient outcomes. It appears to be a suitable and reasonably lasting option for the treatment of medial compartment OA.

Return to Sport and Work Following Distal Femoral Varus Osteotomy: A Systematic Review

Background: Distal femoral varus osteotomy (DFVO) is an effective surgical intervention for the management of symptomatic valgus malalignment of the knee. Because it preserves the native knee joint and its ligamentous stability, DFVO is preferred to total knee arthroplasty (TKA) in the young, active population. Purpose: We sought to assess return to work (RTW) and return to sport (RTS) rates following DFVO for valgus malalignment of the knee. Methods: For this systematic review, we searched EMBASE, MEDLINE, and Web of Science from inception through December 31, 2020. English language studies of all levels of evidence explicitly reporting on RTS and RTW rates following DFVO for valgus malalignment of the knee were eligible for inclusion. Results: Seven studies and 127 patients were included in our analysis. Mean age was 32.4 ± 8.8 years with men comprising 46.7% ± 22.3% of study populations. The mean RTS rate was 87.2% ± 10.7%, with a return to preoperative activity levels rate of 65.4% ± 26.8%. The mean RTW rate was 81.8% ± 23.3%, with a return to preoperative activity levels of 72.8% ± 18.1%. The mean reoperation rate was 35.6% ± 18.8% within a mean follow-up period of 5.5 ± 1.9 years. Conclusions: This systematic review of low-level studies found DFVO to be a safe and effective procedure for the management of genu valgum in young, active populations, with most patients returning to sport and/or work, although not all at their preoperative activity levels. A paucity of data surrounds RTS and RTW rates following DFVO. Future studies should explicitly report both return to activity rates and whether patients returned to their preoperative activity levels.

Real-world evidence of mesenchymal stem cell therapy in knee osteoarthritis: a large prospective two-year case series

Objective: To evaluate the long-term safety and efficacy of adipose-derived mesenchymal stem cell (ADMSC) therapy in the treatment of knee osteoarthritis (OA). Methods: 329 participants with knee OA underwent intra-articular ADMSC therapy. Participants were followed up for 24 months and were separated based on radiological OA grade. Results: Treatment was well tolerated with no related serious adverse events. All participant groups reported clinically and statistically significant pain improvement. Clinical outcome was not influenced by patients' age or BMI. Conclusion: ADMSC therapy is an effective, safe and long-lasting treatment option for knee OA with the potential to delay total joint replacement. In addition to the observed clinical benefits, ADMSC therapy promises to reduce the global economic burden of OA. Trial registration number: ACTRN12617000638336.

Clinical Outcomes, Health Care Costs and Prognostic Factors for Total Knee Arthroplasty: A Multilevel Analysis of a National Cohort Study Using Administrative Claims Data

Total knee arthroplasty (TKA) is one of the most frequent orthopaedic surgeries. The purpose of this study was to determine the 30-day postoperative mortality rate, total episode-of-care costs, and prognostic factors associated with these outcomes, for adult patients who underwent TKA in Colombia's contributory health care system. A retrospective cohort study of all adult patients enrolled in Colombia's contributory health system, who underwent TKA between January 1, 2012 and November 30, 2015 was performed. Thirty-day postoperative mortality rates, 30-day ICU admissions rates, 30-day hospital readmission rates, 1-year arthroplasty revision rates, and total episode-of-care costs were estimated. Multilevel, generalized linear models were generated, to determine the prognostic factors associated with outcomes presented. A total of 12,453 patients were included. The 30-day mortality rate was 0.13 per 100 surgeries and the ICU admissions rate at 30 days postoperative was 4.44 per 100 surgeries. The 30-day hospital readmission rate was 4.28 per 100 surgeries and the 1-year arthroplasty revision rate was 1.22 per 100 surgeries. The prognostic factors associated with mortality were age, Charlson Index, and type of insurer. The prognostic factors associated with hospital readmission were age category, Charlson Index, and geographic region; younger age and higher Charlson Index were found to be associated with a higher 1-year arthroplasty revision rate. The median of total episode-of-care costs was USD$ 6,190.07 (interquartile range: 2,299-7,282). The multivariate model found that age, the Charlson Index, the Atlantic region, and type of insurer were associated with the costs incurred by the health system. For patients undergoing TKA in Colombia, age, the Charlson Index, insurers, and geographic region are associated with mortality, ICU admissions, 30-day hospital readmissions, 1-year arthroplasty revisions, and total costs incurred by the health system.

Return to work after primary total hip or knee arthroplasty. First French study. Retrospective study of 241 cases

INTRODUCTION

The quality and reliability of the results of primary total hip or knee arthroplasty (THA, TKA) have allowed indications to be extended to younger, working-age patients, raising the issue of return to work. This question has never been specifically addressed in THA and TKA in a French population. We therefore conducted a retrospective study to determine: (1) the rates and intervals of return to work, and (2) factors affecting return to work and reasons for non-return.

HYPOTHESIS

Rates and intervals of return to work are comparable to those in Western countries as a whole: 1.1-10.5 weeks in THA and 8-12 weeks in TKA.

MATERIAL AND METHOD

A single-center retrospective study included patients aged under 65 at surgery, between 2009 and 2013. A questionnaire collected population and occupational data. The patients' occupational situation was collected at a minimum 1 year postoperatively. During the study period, 289 TKAs or THAs were performed; 241 patients were recontacted, 144 of whom had been working at the time of surgery: 72 THAs and 72 TKAs. The sex-ratio was well balanced: 69 males, 75 females. Mean age was 55.8±8 years (range, 18.6-65.7 years). The mean time from surgery to data collection was 34.5 months (95% CI, 32.2-36.8 months).

RESULTS

In all, 86 patients (57.6%) returned to work, at a mean 124 days (range, 15-540 days; 95% CI, 102.8-144.4 days). At 3 months, 55.4% of patients (n=46) had returned to work, and 97.6% (n=81) at 12 months. In most cases, patients returned to the same occupation.

CONCLUSION

The study hypothesis was not confirmed. French primary THA or TKA patients returned to work later and less frequently than in other Western countries.

LEVEL OF EVIDENCE

IV, retrospective study without control group.

Amount and type of physical activity and sports from one year forward after hip or knee arthroplasty-A systematic review

INTRODUCTION

After rehabilitation following total hip or knee arthroplasty (THA/TKA), patients are advised to participate in physical activity (PA) and sports. However, profound insight into whether people adopt a physically active lifestyle is lacking. Aim is to gain insight into the performed amount and type of PA (including sports) and time spent sedentarily by persons after THA/TKA.

METHODS

A systematic review (PROSPERO: CRD42020178556). Pubmed, Cinahl, EMBASE and PsycInfo were systematically searched for articles reporting on amount of PA, and on the kind of activities performed between January 1995-January 2021. Quality of the articles was assessed with the adapted tool from Borghouts et al.

RESULTS

The search retrieved 5029 articles, leading to inclusion of 125 articles reporting data of 123 groups; 53 articles reported on subjects post-THA, 16 on post-hip-resurfacing arthroplasty, 40 on post-TKA, 15 on post-unicompartimental knee arthroplasty and 12 on a mix of arthroplasty types. With respect to quality assessment, 14 articles (11%) met three or fewer criteria, 29 (24%) met four, 32 (26%) met five, 42 (34%) met six, and 6 (5%) met seven out of the eight criteria. PA levels were comparable for THA and TKA, showing a low to moderately active population. Time spent was mostly of low intensity. Roughly 50% of -subjects met health-enhancing PA guidelines. They spent the largest part of their day sedentarily. Sports participation was relatively high (rates above 70%). Most participation was in low-impact sports at a recreational level. Roughly speaking, participants were engaged in sports 3 hours/week, consisting of about three 1-hour sessions.

CONCLUSION

Activity levels seem to be low; less than half of them seemed to perform the advised amount of PA following health-enhancing guidelines Sports participation levels were high. However, many articles were unclear about the definition of sports participation, which could have led to overestimation.

Role of joint distraction in osteoarthritis of the knee: Basic science, principles and outcomes

The burden of knee osteoarthritis (OA) is increasing worldwide. Advanced tibiofemoral joint OA in young patients is particularly a problem with inferior results seen with total knee arthroplasty in this patient population. Knee joint distraction (KJD) has been evaluated recently as a joint preserving procedure for young patients with advanced tibiofemoral osteoarthritis, to delay the need for a primary total knee arthroplasty (TKA). This will decrease the risk for revision TKA later in life. KJD temporarily unloads the knee joint and keeps the tibia and femur separated over a course of 6 weeks. Outcomes of KJD appear promising. Through this article, the authors hope to share from their collective experience as well as the available literature on the basic science, principles of surgery and outcomes of KJD.

Return to work after lumbar disc herniation surgery: an occupational cohort study

Background and purpose - Lumbar disc herniation is a common surgically treated condition in the working-age population. We assessed health-related risk factors for return to work (RTW) after excision of lumbar disc herniation. Previous studies on the subject have had partly contradictory findings.Patients and methods - RTW of 389 (n = 111 male, n = 278 female; mean age 46 years, SD 8.9) employees who underwent excision of lumbar disc herniation was assessed based on the Finnish Public Sector Study (FPS). Baseline information on occupation, preceding health, and health-risk behaviors was derived from linkage to national health registers and FPS surveys before the operation. The likelihood of RTW was analyzed using Cox proportional hazard univariable and multivariable modelling.Results - 95% of the patients had returned to work at 12 months after surgery, after on average 78 days of sickness absence. Faster RTW in the univariable Cox model was associated with a small number of sick leave days (< 30 days) before operation (HR 1.3, 95% CI 1.1-1.6); high occupational position (HR 1.6, CI 1.2-2.1); and age under 40 years (HR 1.5, CI 1.1-1.9). RTW was not associated with sex or the health-related risk factors obesity, physical inactivity, smoking, heavy alcohol consumption, poor self-rated health, psychological distress, comorbid conditions, or purchases of pain or antidepressant medications in either the univariable or multivariable model.Interpretation - Almost all employees returned to work after excision of lumbar disc herniation. Older age, manual job, and prolonged sick leave before the excision of lumbar disc herniation were risk factors for delayed return to work after the surgery.

Measurement properties of UCLA Activity Scale for hip and knee arthroplasty patients and translation and cultural adaptation into Danish

Background and purpose - The UCLA Activity Scale (UCLA) is a questionnaire assessing physical activity level from 1 (low) to 10 (high) in patients undergoing hip or knee arthroplasty (HA/KA). After translation and cultural adaptation, we evaluated the measurement properties of the Danish UCLA.Patients and methods - After dual panel translation, cognitive interviews were performed among 55 HA/KA patients. An orthopedic surgeon and a physiotherapist estimated UCLA scores for 80 KA patients based on short interviews. Measurement properties were evaluated in 130 HA and 134 KA patients preoperatively and 1-year postoperatively.Results - To suit Danish patients of today, several adaptations were required. Prior to interviews, 4 patients were excluded, and 11 misinterpreted the answer options. Examiners rated the remaining 65 patients (mean age 67 years) 0.2-1.6 UCLA levels lower than patients themselves. The 130 HA and 134 KA patients (mean age 71/68 years) changed from 4.3 (SD 1.9)/4.5 (1.8) preoperatively to 6.6 (1.8)/6.2 (1.0) at 1-year follow-up. 103 (79%) HA and 89 (66%) KA patients reported increased activity. Effect sizes were large (1.2/0.96). Knee patients reaching minimal important change (MIC, ≥ 8 Oxford Knee Score points) had higher 1-year UCLA scores than patients not reaching MIC.Interpretation - Original scale development was undocumented. Content validity was questionable, and there was discrepancy between patient and examiner estimates. UCLA appears valuable for measuring change in self-reported physical activity on a group level. 4 out of 5 HA patients and 2 out of 3 KA patients were more physically active 1 year after joint replacement surgery.

Recovery Courses of Patients Who Return to Work by 3, 6 or 12 Months After Total Knee Arthroplasty

Purpose This study compared the preoperative levels and postoperative recovery courses of physical and mental impairments, activity limitations and participation restrictions of working-age patients who return to work (RTW) by 3, 6 or 12 months after total knee arthroplasty (TKA). Methods A prospective survey study including TKA patients (aged < 65) (n = 146) who returned to work (RdTW) in the first postoperative year. Three groups were compared: those who returned by 3 (n = 35), 6 (n = 40) or 12 (n = 29) months. Surveys were completed preoperatively and at 6 weeks and 3, 6 and 12 months postoperatively. Outcomes represented domains of the International Classification of Functioning, i.e. physical impairments (pain, stiffness, vitality), mental impairments (mental health and depressive symptoms), activity limitations (physical functioning) and participation restrictions (social and work functioning). Results Preoperative knee-specific pain and physical functioning levels were better among patients who RdTW by 3 months, compared to those who returned by 12 months. Patients who RdTW by 3 months experienced significantly better recovery from physical impairments than those who returned by 6 months (on general pain) or 12 months (on general and knee-specific pain and on stiffness). Patients returning by 3 months experienced significantly better recovery from activity limitations (on knee-specific physical functioning). Conclusions To optimize return to work outcome after TKA surgery, the focus should lie on physical impairments (general and knee-specific pain, stiffness) and activity limitations (knee-specific physical functioning) during recovery.

Comparing the Fiscal Consequences of Controlled and Uncontrolled Osteoarthritis Pain Applying a UK Public Economic Perspective

Background: Individuals experiencing osteoarthritis (OA) pain can pose significant costs for governments due to reduced work activity in these individuals and increasing reliance on public support benefits. In this analysis we capture the broader economic impact of OA pain by applying a government perspective, public economic framework to assess controlled and uncontrolled pain. Methods: We used a Markov model to compare labour market participation in people with uncontrolled OA hip or knee pain compared to a cohort with controlled OA pain. The likelihood of employment, long-term sickness, disability, and early retirement in those with controlled pain used publicly available UK data. The relative effect of uncontrolled OA pain on fiscal outcomes is drawn from peer reviewed publications reporting reduced work activity and reliance on public benefits for people with uncontrolled OA pain. Lost tax revenue was derived using UK tax rates and national insurance contributions applied to annual earnings. Social benefit rules were applied to calculate government financial support to individuals. Health-care costs were calculated based on estimates from an UK observational study. The base case analysis compared the projected lost tax revenue and transfer payments for a 50-year-old cohort with severe OA pain, retiring at age 65. Results: For a 50-year-old individual with moderate uncontrolled OA pain with 15-years remaining work expectancy, the model estimated a £62 383 reduction in employment earnings, a £24 307 reduction in tax contributions and a need for £16 034 in government benefits, compared to a person with controlled OA pain. In people with severe uncontrolled OA pain incremental foregone earnings were estimated to be £126 384, £44 925 were not paid through taxation and £25 829 were received in public benefits, compared to the controlled pain cohort. Health-care costs represented 13% and 12% of all OA-related fiscal cost in the moderate uncontrolled OA pain and severe uncontrolled OA pain comparison, respectively. Conclusions: For governments, maintaining an active workforce is paramount to maintaining economic growth and reducing spending on government programs. The approach described here can be used to augment cost-effectiveness models to inform a range of stakeholders of benefits attributed to controlled OA pain.

Accelerometer Measured Sedentary and Physical Activity Behaviors of Working Patients after Total Knee Arthroplasty, and their Compensation Between Occupational and Leisure Time

Purpose Objective measurements of sedentary and physical activity (PA) behavior are scarce among working-age patients who undergo total knee arthroplasty (TKA). Aim was to assess sedentary and PA behaviors using accelerometers and to identify compensation effects between occupational and leisure time of sedentary and PA behavior. Methods One year post-TKA, 51 patients wore an ActiGraph(GT3x) accelerometer for 7 days. Sedentary time, prolonged sedentary bouts (≥ 30 min) and PA (light-intensity and moderate-to-vigorous PA) were examined. Compliance with the guideline of > 150 min moderate-to-vigorous PA per week was calculated. Compensation effects were analyzed using multilevel models, splitting effects into routine and within-day compensation, stratifying by physical and non-physical jobs. The routine compensation effects are the ones of interest, representing habitual compensation during a week. Results Participants spent 60% of time in sedentary bouts and 17% in prolonged sedentary bouts, with 37% of PA spent in light-intensity and 3% in moderate-to-vigorous activity. About 70% of patients met the PA guideline. Routine compensation effects were found for workers in physical jobs, who compensated for their occupational light-intensity PA with less light-intensity PA during leisure time. Workers in non-physical jobs did not compensate for their occupational prolonged sedentary bouts, as these continued during leisure time. Conclusion This study showed that working TKA patients are highly sedentary 1 year after surgery, but most met the PA guideline. Especially those with non-physical jobs do not compensate for their occupational prolonged sedentary bouts. This stresses the need to stimulate PA among TKA patients not complying with the guidelines and those with non-physical jobs.

Return to Work Following Total Knee and Hip Arthroplasty: The Effect of Patient Intent and Preoperative Work Status

BACKGROUND

The ability of total knee and hip arthroplasty (TKA/THA) to facilitate return to work (RTW) when it is the patient's preoperative intent to do so remains unclear. We aimed at determining whether TKA/THA facilitated RTW in patients of working age who intended to return.

METHODS

This is a prospective cohort study of 173 consecutive patients <65 years of age, undergoing unilateral TKA (n = 82: median age 58; range, 39-65; 36 [43.9%] male) or THA (n = 91: median age 59; range, 34-65; 42 [46.2%] male) during 2018. Oxford knee/hip scores, Oxford-Activity and Participation Questionnaire, and EuroQol-5 dimension (EQ-5D) scores were measured preoperatively and at 1 year when an employment questionnaire was also completed.

RESULTS

Of patients who intended to RTW, 44 of 52 (84.6%) RTW by 1 year following TKA (at mean 14.8 ± 8.4 weeks) and 53 of 60 (88.3%) following THA (at mean 13.6 ± 7.5 weeks). Failure to RTW despite intent was associated with job physicality for TKA (P = .004) and negative preoperative EQ-5D for THA (P = .01). In patients unable to work before surgery due to joint disease, fewer RTW: 4 of 21 (19.0%) after TKA; and 6 of 17 (35.3%) after THA. Preoperative Oxford knee score >18.5 predicted RTW with 74% sensitivity (P < .001); preoperative Oxford hip score >19.5 predicted RTW with 75% sensitivity (P < .001). Preoperative EQ-5D indices were similarly predictive (P < .001).

CONCLUSION

In this United Kingdom study, preoperative intent to RTW was the most powerful predictor of actual RTW following TKA/THA. Where patients intend to RTW following TKA/THA, 85% RTW following TKA and 88% following THA.

Accuracy in the Execution of Pre-operative Plan for Limb Alignment and Implant Positioning in Robotic-arm Assisted Total Knee Arthroplasty and Manual Total Knee Arthroplasty: A Prospective Observational Study

AIM

The objective of the study is to compare the accuracy of implant positioning and limb alignment achieved in robotic-arm assisted total knee arthroplasty(RATKA) and manual total knee arthroplasty(MTKA) to their respective preoperative plan.

PATIENTS AND METHODS

This was a prospective observational study conducted in a tertiary care centre between August 2018 and January 2020. 143 consecutive RATKA(105 patients) and 151 consecutive MTKA(111 patients) performed by two experienced arthroplasty surgeons were included. Two independent observers evaluated the accuracy of implant positioning by measuring the radiological parameters according to the Knee-Society-Roentgenographic-Evaluation-System and limb alignment from postoperative weight-bearing scanogram. Outcomes were defined, based on the degree of deviation of measurements from the planned position and alignment, as excellent(0-1.99°), acceptable(2.00-2.99°) and outlier(≥ 3.00°).

RESULTS

There were no systematic differences in the demographic and baseline characteristics between RATKA and MTKA. Statistically significant outcomes were observed favouring robotic group for postoperative mechanical axis (p < .001), coronal inclination of the femoral component (p < 0.001), coronal inclination of tibial component (p < 0.001), and sagittal inclination of tibial component (p < 0.001). There was no significant difference in the sagittal inclination of the femoral component (p = 0.566). The percentage of knees in the 'excellent' group were higher in RATKA compared to MTKA. There was absolutely no outlier in terms of limb alignment in the RATKA group versus 23.8% (p < 0.001) in the MTKA group. All the measurements showed high interobserver and intraobserver reliability.

CONCLUSION

Robotic-arm assisted TKA executed the preoperative plan more accurately with respect to limb alignment and implant positioning compared to manual TKA, even when the surgeons were more experienced in the latter.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-020-00324-y.

The projected volume of primary and revision total knee arthroplasty will place an immense burden on future health care systems over the next 30 years

PURPOSE

Total knee arthroplasty (TKA) rates have increased substantially in the recent decades worldwide, with Germany being one of the leading countries in the prevalence of TKA. The aim of this study was to provide an overview of treatment changes during the last decade and to project the expected burden of primary and revision TKA (rTKA) for the next 30 years.

METHODS

Comprehensive nationwide data from Germany was used to quantify primary and revision TKA rates as a function of age and gender. Projections were performed with use of a Poisson regression models and a combination of exponential smoothing and autoregressive integrated moving average models on historical procedure rates in relation to official population projections from 2020 to 2050.

RESULTS

The incidence rate of primary TKAs is projected to increase by around 43% to 299 per 100,000 inhabitants [95% CI 231-368], leading to a projected total number of 225,957 primary TKAs in 2050 (95% CI 178,804-276,442). This increase has been related to a growing number of TKA performed in male patients, with the highest increase modelled in patients between 50 and 65 years of age. At the same time, the annual total number of revision procedures is forecast to increase even more rapidly by almost 90%, accounting for 47,313 (95% CI 15,741-78,885; IR = 62.7 per 100,000, 95% CI 20.8-104.5) procedures by 2050. Those numbers are primarily associated with a rising number of rTKAs secondary to periprosthetic joint infection (PJI).

CONCLUSIONS

Using this country- specific forecast approach, a rising number of primary TKA and an even more rapidly growing number of rTKA, especially for PJI, has been projected until 2050, which will inevitably provide a huge challenge for the future health care system. As many other industrialized nations will face similar demographic and procedure-specific developments, these forecasts should be alarming for many health care systems worldwide and emphasize the tremendous need for an appropriate financial and human resource management in the future.

LEVEL OF EVIDENCE

Level III, prognostic study, economic and decision analysis.

Occupational advice to help people return to work following lower limb arthroplasty: the OPAL intervention mapping study

BACKGROUND

Hip and knee replacements are regularly carried out for patients who work. There is little evidence about these patients' needs and the factors influencing their return to work. There is a paucity of guidance to help patients return to work after surgery and a need for structured occupational advice to enable them to return to work safely and effectively.

OBJECTIVES

To develop an occupational advice intervention to support early recovery to usual activities including work that is tailored to the requirements of patients undergoing hip or knee replacements. To test the acceptability, practicality and feasibility of this intervention within current care frameworks.

DESIGN

An intervention mapping approach was used to develop the intervention. The research methods employed were rapid evidence synthesis, qualitative interviews with patients and stakeholders, a prospective cohort study, a survey of clinical practice and a modified Delphi consensus process. The developed intervention was implemented and assessed during the final feasibility stage of the intervention mapping process.

SETTING

Orthopaedic departments in NHS secondary care.

PARTICIPANTS

Patients who were in work and intending to return to work following primary elective hip or knee replacement surgery, health-care professionals and employers.

INTERVENTIONS

Occupational advice intervention.

MAIN OUTCOME MEASURES

Development of an occupational advice intervention, fidelity of the developed intervention when delivered in a clinical setting, patient and clinician perspectives of the intervention and preliminary assessments of intervention effectiveness and cost.

RESULTS

A cohort study (154 patients), 110 stakeholder interviews, a survey of practice (152 respondents) and evidence synthesis provided the necessary information to develop the intervention. The intervention included information resources, a personalised return-to-work plan and co-ordination from the health-care team to support the delivery of 13 patient and 20 staff performance objectives. To support delivery, a range of tools (e.g. occupational checklists, patient workbooks and employer information), roles (e.g. return-to-work co-ordinator) and training resources were created. Feasibility was assessed for 21 of the 26 patients recruited from three NHS trusts. Adherence to the defined performance objectives was 75% for patient performance objectives and 74% for staff performance objectives. The intervention was generally well received, although the short time frame available for implementation and concurrent research evaluation led to some confusion among patients and those delivering the intervention regarding its purpose and the roles and responsibilities of key staff.

LIMITATIONS

Implementation and uptake of the intervention was not standardised and was limited by the study time frame. Evaluation of the intervention involved a small number of patients, which limited the ability to assess it.

CONCLUSIONS

The developed occupational advice intervention supports best practice. Evaluation demonstrated good rates of adherence against defined performance objectives. However, a number of operational and implementation issues require further attention.

FUTURE WORK

The intervention warrants a randomised controlled trial to assess its clinical effectiveness and cost-effectiveness to improve rates and timing of sustained return to work after surgery. This research should include the development of a robust implementation strategy to ensure that adoption is sustained.

STUDY REGISTRATION

Current Controlled Trials ISRCTN27426982 and PROSPERO CRD42016045235.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 45. See the NIHR Journals Library website for further project information.

Return to Work After Total Joint Arthroplasty: A Predictive Model

Returning to work after surgery is a primary concern of patients who are contemplating total joint arthroplasty (TJA). The ability to return to work has enormous influence on the patient's independence, financial well-being, and daily activities. The goal of this study was to determine the independent patient variables that predict return to work as well as to create a predictive model. From June 2017 to December 2017, a total of 391 patients who underwent primary TJA (243 hips, 148 knees) were prospectively enrolled in the study to obtain information on return to work after surgery. Patients were sent a series of questions in a biweekly survey. Information was collected on the physical demands of their occupation, the number of hours spent standing, the limitations to return to work, and the use of assistive devices. Bivariate analysis was performed, and a multiple linear regression model was created. Most (89.6%) patients returned to work within 12 weeks of surgery. Patients who underwent total hip arthroplasty returned to work earlier than those who underwent total knee arthroplasty (5.56 vs 7.79 weeks, respectively). Analysis showed the following independent predictors for faster return to work: self-employment, availability of light-duty work, male sex, and higher income. Predictors for slower return to work included a physically demanding occupation (at least 50% physical duties), knee arthroplasty, longer length of stay, and a job requiring more hours spent standing. This model reported an adjusted R² of 0.332. The findings provide an objective predictive model of the patient- and procedure-specific characteristics that affect postoperative return to work. Surgeons should consider these factors when counseling patients on their postoperative expectations. [Orthopedics. 2020;43(5):e415-e420.].

Development of an occupational advice intervention for patients undergoing elective hip and knee replacement: a Delphi study

OBJECTIVE

To obtain consensus on the content and delivery of an occupational advice intervention for patients undergoing primary hip and knee replacement surgery. The primary targets for the intervention were (1) patients, carers and employers through the provision of individualised support and information about returning to work and (2) hospital orthopaedic teams through the development of a framework and materials to enable this support and information to be delivered.

DESIGN

Modified Delphi study as part of a wider intervention development study (The Occupational advice for Patients undergoing Arthroplasty of the Lower limb (OPAL) study: Health Technology Assessment Reference 15/28/02) (ISRCTN27426982).

SETTING

Five stakeholder groups (patients, employers, orthopaedic surgeons, general practitioners, allied health professionals and nurses) recruited from across the UK.

PARTICIPANTS

Sixty-six participants.

METHODS

Statements for the Delphi process were developed relating to the content, format, delivery, timing and measurement of an occupational advice intervention. The statements were based on evidence gathered through the OPAL study that was processed using an intervention mapping framework. Intervention content was examined in round 1 and intervention format, delivery, timing and measurement were examined in round 2. In round 3, the developed intervention was presented to the stakeholder groups for comment.

CONSENSUS

For rounds 1 and 2, consensus was defined as 70% agreement or disagreement on a 4-point scale. Statements reaching consensus were ranked according to the distribution of responses to create a hierarchy of agreement. Round 3 comments were used to revise the final version of the developed occupational advice intervention.

RESULTS

Consensus was reached for 36 of 64 round 1 content statements (all agreement). In round 2, 13 questions were carried forward and an additional 81 statements were presented. Of these, 49 reached consensus (44 agreement/5 disagreement). Eleven respondents provided an appraisal of the intervention in round 3.

CONCLUSIONS

The Delphi process informed the development of an occupational advice intervention as part of a wider intervention development study. Stakeholder agreement was achieved for a large number of intervention elements encompassing the content, format, delivery and timing of the intervention. The effectiveness and cost-effectiveness of the developed intervention will require evaluation in a randomised controlled trial.

TRIAL REGISTRATION NUMBER

International Standard Randomised Controlled Trials Number Trial ID: ISRCTN27426982.

Effect of knee arthroplasty on sports participation and activity levels: a systematic review and meta-analysis

Objective

Desires and expectations of patients in regard to resume participation in sport activities after knee arthroplasty strongly increased in recent years. Therefore, this review systematically reviewed the available scientific literature on the effect of knee arthroplasty on sports participation and activity levels.

Design

Systematic review and meta-analysis.

Data sources

PubMed, Embase, SPORTDiscus and reference lists were searched in February 2019.

Studies eligibility criteria

Inclusion of knee osteoarthritis patients who underwent total knee arthroplasty (TKA) and/or unicondylar knee arthroplasty. Studies had to include at least one preoperative and one postoperative measure (≥1 year post surgery) of an outcome variable of interest (ie, activity level: University of California, Los Angeles and/or Lower Extremity Activity Scale; sport participation: type of sport activity survey).

Results

Nineteen studies were included, consisting data from 4074 patients. Knee arthroplasty has in general a positive effect on activity level and sport participation. Most patients who have stopped participating in sport activities in the year prior to surgery, however, do not seem to reinitiate their sport activities after surgery, in particular after a TKA. In contrast, patients who continue to participate in sport activities until surgery appear to become even more active in low-impact and medium-impact sports than before the onset of restricting symptoms.

Conclusions

Knee arthroplasty is an effective treatment in resuming sports participation and physical activity levels. However, to achieve the full benefits from knee arthroplasty, strategies and guidelines aimed to keep patients capable and motivated to participate in (low-impact or medium-impact) sport activities until close before surgery are warranted.

Two-year recovery courses of physical and mental impairments, activity limitations, and participation restrictions after total knee arthroplasty among working-age patients

Purpose: Total knee arthroplasty is increasingly performed on working-age individuals, but little is known about their recovery process. Therefore this study examined recovery courses of physical and mental impairments, activity limitations and participation restrictions among working-age total knee arthroplasty recipients. Associated sociodemographic and health-related factors were also evaluated.Materials and methods: A prospective study among working total knee arthroplasty patients (aged <65 years) (n = 146). Surveys were completed preoperatively and 6 weeks and 3, 6, 12, and 24 months postoperatively. Outcomes represented domains of the International Classification of Functioning, that is, physical impairments (pain, stiffness, vitality), mental impairments (mental health, depressive symptoms), activity limitations (physical functioning), and participation restrictions (social-, work functioning, working hours). Covariates included age, gender, education, home situation, body mass index, and comorbidity.Results: Largest improvements in physical and mental impairments and activity limitations were observed until 3 months postoperatively. Participation in social roles improved early after surgery, and improvements in work participation occurred from 6 to 12 months. Older age, being male and fewer comorbidities were associated with better recovery courses.Conclusion: Working-age total knee arthroplasty patients recover soon from physical and mental impairments, activity limitations, and participation in social roles, but participation at work occurs later. Younger patients, females, and those with musculoskeletal comorbidities appear at risk for suboptimal recovery after total knee arthroplasty.Implications for rehabilitationAn increasing number of working-age patients are asking for total knee arthroplasty and have high expectations of total knee arthroplasty, in particular, to participate in the workforce again;Recovery after total knee arthroplasty (TKA) does not occur in the short term and is not limited to clinical improvements for working-age TKA recipients only, as an important part of recovery, that is, participation occurs in the long term (>6 months);Closer collaboration between occupational physicians and orthopedic surgeons might result in increased and earlier ability to work full contractual hours;Rehabilitation after TKA should focus on patients with multiple comorbidities, whereby musculoskeletal diseases may even need additional preoperative treatment to optimize outcomes and prevent work disability.

Preoperative low scores of Life Satisfaction Rating predicts poor outcomes after total knee arthroplasty: a prospective observational study

Background

Despite the continued improvement in the surgical techniques during primary total knee arthroplasty (TKA), literatures indicate that up to 10 to 20% patients are not satisfied with their outcomes. Psychological factors in this dissatisfaction are yet to be clearly identified. The aim of this study is to develop a method to assess whether the patient’s current mental state is suitable enough to accept a TKA surgery.

Methods

Preoperative demographic and clinical data of 532 patients who underwent TKA were prospectively obtained from January 2012 until December 2016. We recorded the scores evaluated by SF-36 questionnaire and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) preoperatively and 1 year postoperatively. Preoperative Life Satisfaction Rating (LSR) is emphatically evaluated.

Results

Poor preoperative score of LSR was a significant predictor of dissatisfaction after TKA. Patients with low LSR reported significant pain and stiffness, although there was no remarkable effect on functionality of the replaced joint. The results also showed that age and BMI were not strong predictors of satisfaction in TKA.

Conclusion

Our outcomes can help clinicians evaluate whether a patient’s current mental status is favorable for TKA. If patients have extreme low scores of LSR (less than 10), a psychological intervention should be recommended for better satisfaction following a TKA surgery. This would also allow surgeons to individually assess the risks and benefits of surgery.

Patients return to work sooner after unicompartmental knee arthroplasty than after total knee arthroplasty

PURPOSE

It is not yet known if unicompartmental knee arthroplasty (UKA) patients are more likely to return to work sooner or have improved ability to work (i.e., workability) than total knee arthroplasty (TKA) patients. The following questions were addressed: patients were assessed to determine: (1) whether they returned to work sooner following UKA compared to TKA; (2) whether UKA patients had better WORQ function scores compared to TKA patients; and (3) if UKA patients have higher workability scores and greater satisfaction regarding workability than TKA patients.

METHODS

A multicenter retrospective cohort study was performed that included patients at least 2 years after having undergone either UKA or TKA surgery and on the condition that patients had been in work in the 2 years prior to surgery. Time period between stopping work and returning to work was assessed; the WORQ scores (0 = worst-100 = best) and the Work Ability Index (WAI = 0-10) and reported satisfaction with work ability.

RESULTS

UKA patients (n = 157, median 60 years, 51% male) were compared to TKA patients (n = 167, median 60 years, 49% male) (n.s.). Of the 157 UKA patients, 115 (73%) returned to work within 2 years compared to 121 (72%) of TKA patients (n.s.). More UKA patients return to work within 3 months (73% versus 48%) (p < 0.01). WORQ scores improved similarly in both groups. The WAI was also comparable between the groups. Dissatisfaction with workability was comparable (UKA 15% versus TKA 18% (n.s.).

CONCLUSION

TKA and UKA patients have similar WORQ, WAI, and satisfaction scores. However, in this study population, UKA patients to return to work after surgery significantly sooner than TKA patients, which improves their quality of life and allows them to participate actively in society. This information can help health care providers and patients weigh-up the pros and cons and choose the best treatment and timing for patients in the working population.

LEVEL OF EVIDENCE

III.

Higher Rate of Early Revision Following Primary Total Knee Arthroplasty in Patients Under Age 55: A Cautionary Tale

BACKGROUND

There has been an increased number of total knee arthroplasties (TKAs) performed in young and active patients. Although improved materials have decreased the likelihood of early catastrophic wear, concerns remain with the performance and survivorship of TKA implants in this patient population. The purpose this study is to evaluate perioperative complications, patient-reported outcomes, and implant survivorship of TKAs performed in patients under age 55.

METHODS

We retrospectively reviewed 4259 primary TKAs performed over a 4-year period. There were 741 TKAs in patients under age 55. The primary outcome of interest was rate of revision at 30 days, 1, 2, and 5-year time points. Secondary outcomes included postoperative transfusion rate, length of stay, rate of deep vein thrombosis/pulmonary embolism, need for manipulation under anesthesia, readmission and reoperation within 30 days, as well as patient-reported outcomes.

RESULTS

There were 3518 patients over 55 years and 741 patients under 55 years. Overall, 175 patients required revision (4.1%). Patients under 55 years had significantly higher cumulative revision rate at 1 (3.4% vs 1.8%, P < .001), 2 (5.0% vs 2.4%, P < .001), and 5 years (7.3% vs 3.7%, P < .001). Patients under 55 years had a higher rate of early reoperation. Patients over 55 years required more transfusions and suffered a higher rate of early deep vein thrombosis. Patients over 55 years had significantly greater improvements in Patient Reported Outcome Measurement Information System Global 10 Physical scores at 6 months postoperatively compared to patients under 55 years.

CONCLUSIONS

Despite improvements in TKA implants, young and active patients remained at higher risk of early revision compared to older patients. The data should be used to counsel young prospective TKA patients about the early risk of reoperation and non-wear-related complications.

Activity Impairment and Work Productivity Loss After Total Knee Arthroplasty: A Prospective Study

BACKGROUND

Total knee arthroplasty (TKA) is increasingly performed among working-aged individuals, highlighting the importance of work-related outcomes. Therefore, the aim is to examine the extent of both activity impairment outside work and work productivity (absenteeism, presenteeism, at-work productivity loss) at 6 and 24 months post-TKA surgery. Additionally, associated risk factors with these outcomes were evaluated.

METHODS

This analysis included 183 patients <70 years undergoing TKA who completed questionnaires pre-operatively and during follow-up. Outcomes were derived from the Work Productivity and Activity Impairment questionnaire and included activity impairment, absenteeism (sick leave), presenteeism (reduced work performance), and at-work productivity loss (overall work productivity loss). All outcomes were scaled 0%-100%, with higher percentages indicating higher impairments. Covariates included age, gender, education, pain catastrophizing, pain, function, psychological distress, and knee-related and health-related quality of life. Linear and logistic regression was used to assess associations between covariates and Work Productivity and Activity Impairment scores at follow-up.

RESULTS

At 6 months, the mean activity impairment was 22.8% (standard deviation [SD] 23.5) dropping to 17.1% (23.1) by 24 months. Among workers, presenteeism was 18.4% (24.6) and at-work productivity loss was 20.8% (26.1). Both dropped significantly by 24 months to 14.2% (22.4) and 12.9% (20.9), respectively. Absenteeism levels were low at both time points. Pain catastrophizing was associated with all outcomes.

CONCLUSION

This study showed that activity impairment and work productivity loss are common following TKA, decreased significantly over time, but still existed 2 years post-operatively. Those reporting high levels of pain catastrophizing may benefit from targeted rehabilitation guidance to reduce and possibly prevent activity impairment and work productivity loss.

Robotic technology in total knee arthroplasty: a systematic review

Robotic total knee arthroplasty (TKA) improves the accuracy of implant positioning and reduces outliers in achieving the planned limb alignment compared to conventional jig-based TKA.Robotic TKA does not have a learning curve effect for achieving the planned implant positioning. The learning curve for achieving operative times comparable to conventional jig-based TKA is 7-20 robotic TKA cases.Cadaveric studies have shown robotic TKA is associated with reduced iatrogenic injury to the periarticular soft tissue envelope compared to conventional jig-based TKA.Robotic TKA is associated with decreased postoperative pain, enhanced early functional rehabilitation, and decreased time to hospital discharge compared to conventional jig-based TKA. However, there are no differences in medium- to long-term functional outcomes between conventional jig-based TKA and robotic TKA.Limitations of robotic TKA include high installation costs, additional radiation exposure, learning curves for gaining surgical proficiency, and compatibility of the robotic technology with a limited number of implant designs.Further higher quality studies are required to compare differences in conventional TKA versus robotic TKA in relation to long-term functional outcomes, implant survivorship, time to revision surgery, and cost-effectiveness. Cite this article: EFORT Open Rev 2019;4:611-617. DOI: 10.1302/2058-5241.4.190022.

Total hip and knee replacement and return to work: clinicians' perspectives

PURPOSE

An ageing workforce means that our understanding of return to work following total hip and knee replacement is of increasing importance. The purpose of this qualitative study was to explore the views and experiences of clinicians in treating working patients undergoing total hip or knee replacement.

MATERIALS AND METHODS

We conducted semi-structured interviews in primary and secondary National Health Service care using framework methodology. A total of 40 interviews were conducted. Participants included 12 hospital-based Allied Health Professionals and nurses, 12 orthopedic surgeons, and 16 General Practitioners. Data were analyzed thematically.

RESULTS

A key theme concerned participants' perceptions and experiences around the process and practice of listing working patients for total hip or knee replacement. Four sub-themes were identified; the perceived likelihood of listing employed patients for surgery, expectations and outcomes of surgery, the impact of work issues, and referral procedures and waiting lists.

CONCLUSIONS

Decisions around listing working patients for total hip and knee replacement are complex and difficult. Clinicians need to consistently consider patients' work issues, and to be supported in this by appropriate commissioning and service delivery decisions. Further research is indicated to better understand the work-related expectations and anticipated outcomes of both patients and clinicians, and the optimum timing of surgery to maintain and improve patients' work performance.Implications for rehabilitationClinicians need to consistently consider patients' work issues, and current evidence, in their consultations and decisions regarding total hip and knee replacement.Clinical practice should reflect the growing proportion of working patients undergoing total hip and knee replacement, and routinely measure work outcomes.Changes are required at commissioning and service levels to support clinicians in changing their practice with this patient population.

Are patient-related pre-operative factors influencing return to work after total knee arthroplasty

BACKGROUND

Osteoarthritis is one of the leading causes of disability in working-age patients. The total number of working-age patients undergoing total-knee arthroplasty (TKA) is continuously increasing. The purpose of this study was to identify predictive factors related to general health, health risk behaviors and socioeconomic status influencing the rate of return to work after a TKA.

METHODS

Overall there were 151,901 patients included in the Finnish Public Sector (FPS) study. The response rate varied between 65 and 73% during the study period. We used Cox proportional hazard models to examine patient-related predictive factors that may influence the rate of return to work after TKA in a cohort of patients (n = 452; n = 362 female; mean age 56.4 years). Predictive factors were measured on average 3.6 years before the operation.

RESULTS

Of the patients, 87% returned to work within one year after TKA at a mean of 116 calendar days. In multivariate analysis, patients at sick-leave ≤30 days during the last year before surgery were 2.2 times (95% confidence interval 1.72-2.92) more likely to return to work compared with those with >30 days of sick-leave. Compared with patients in manual work, those in higher or lower level non-manual work showed a 2.6-fold (1.95-3.52) and 1.5-fold (1.15-1.92) increased probability of returning to work. Age, sex, health risk behaviors, obesity, physical comorbidities, common mental disorders, and other studied health-related factors were not associated with the rate of return to work.

CONCLUSIONS

Non-manual job, good self-rated general health and preoperative sick leave ≤30 days are associated with a higher rate of return to work.