Body Mass Index and Functional Mobility Outcome Following Early Rehabilitation After a Total Knee Replacement: A Retrospective Study in Taiwan

Influence of body mass index on early post-operative functional outcomes after total knee arthroplasty: A prospective, clinical and observational study

Background/Purpose: The evidence on the influence of body mass index (BMI) on functional outcomes following total knee arthroplasty (TKA) is conflicting. This study assessed and compared the effect of BMI on early mobility and function after TKA. Methods: Adult patients with osteoarthritis (OA) or rheumatoid arthritis (RA) who received unilateral TKA were recruited and then divided into normal, overweight and obese groups. The pain and functional outcomes of pre/post-TKA were examined using visual analogue scale (VAS) and Lysholm Knee Scale (LKS), respectively. Results: At 3 and 6 weeks post-TKA, LKS score was significantly higher in normal BMI group compared to overweight and obese. Lower BMI gained early improvement in functional outcome than higher BMI groups. However, patients showed considerable functional improvement at 6 months post-TKA, regardless of BMI category. Conclusion: Although BMI levels influence postoperative early functional improvement in TKA patients, the functional benefits after TKA at 6 months were similar regardless of BMI class.

Effects of Sarcopenic Obesity and Its Confounders on Knee Range of Motion Outcome after Total Knee Replacement in Older Adults with Knee Osteoarthritis: A Retrospective Study

Sarcopenic obesity is closely associated with knee osteoarthritis (KOA) and has high risk of total knee replacement (TKR). In addition, poor nutrition status may lead to sarcopenia and physical frailty in KOA and is negatively associated with surgery outcome after TKR. This study investigated the effects of sarcopenic obesity and its confounding factors on recovery in range of motion (ROM) after total knee replacement (TKR) in older adults with KOA. A total of 587 older adults, aged ≥60 years, who had a diagnosis of KOA and underwent TKR, were enrolled in this retrospective cohort study. Sarcopenia and obesity were defined based on cutoff values of appendicular mass index and body mass index for Asian people. Based on the sarcopenia and obesity definitions, patients were classified into three body-composition groups before TKR: sarcopenic-obese, obese, and non-obese. All patients were asked to attend postoperative outpatient follow-up admissions. Knee flexion ROM was measured before and after surgery. A ROM cutoff of 125 degrees was used to identify poor recovery post-surgery. Kaplan-Meier curve analysis was performed to measure the probability of poor ROM recovery among study groups. Cox multivariate regression models were established to calculate the hazard ratios (HRs) of postoperative poor ROM recovery, using potential confounding factors including age, sex, comorbidity, risk of malnutrition, preoperative ROM, and outpatient follow-up duration as covariates. Analyses results showed that patients in the obese and sarcopenic-obese groups had a higher probability of poor ROM recovery compared to the non-obese group (all p < 0.001). Among all body-composition groups, the sarcopenic-obese group yielded the highest risk of postoperative physical difficulty (adjusted HR = 1.63, p = 0.03), independent to the potential confounding factors. Sarcopenic obesity is likely at the high risk of poor ROM outcome following TKR in older individuals with KOA.

Greater risk of all-cause revisions and complications for obese patients in 3 106 381 total knee arthroplasties: a meta-analysis and systematic review

BACKGROUND

Obesity is a major public health issue and has considerable implications on outcomes of total knee arthroplasty (TKA). However, there has been conflicting evidence and conclusions on the effects of obesity on TKA. This meta-analysis compares the outcomes, complications, and peri-operative parameters of TKA in the obese (body mass index [BMI] ≥ 30 kg/m² ) versus non-obese (BMI < 30 kg/m² ) population as well as subgroup analysis of morbidly obese (BMI ≥ 40 kg/m² ) versus non-obese population.

METHODS

A meta-analysis was conducted with a multi-database search according to PRISMA guidelines on 12 September 2019. Data from all published literature meeting inclusion criteria were extracted and analysed.

RESULTS

Ninety-one studies were included, consisting of 917 447 obese and 2 188 834 non-obese TKA. Obese patients had higher risk of all-cause revisions (odds ratio [OR] = 1.15, 95% CI: 1.08-1.24, p < 0.0001), all complications (OR = 1.21, 95% CI: 1.06-1.38, p = 0.004), deep infections (OR = 1.47, 95% CI: 1.27-1.69, p < 0.0001), superficial infections (OR = 1.59, 95% CI: 1.32-1.91, p < 0.0001), wound dehiscence (OR = 1.46, 95% CI: 1.24-1.72, p < 0.0001) and readmissions (OR = 1.21, 95% CI: 1.05-1.40, p = 0.009). Subgroup analysis of morbidly obese patients revealed greater risks of all-cause revisions (OR = 1.25, 95% CI: 1.10-1.43, p = 0.0009), deep infections (OR = 1.98, 95% CI: 1.05-3.75, p = 0.04), superficial infections (OR = 2.44, 95% CI: 2.08-2.88, p < 0.0001) and readmissions (OR = 1.33, 95% CI: 1.20-1.47, p < 0.0001). No analysis was performed on patient reported outcome measures due to heterogeneous reporting methods.

CONCLUSION

Obese and morbidly obese patients have higher risks of revisions and infections post TKA. Surgeons should counsel patients of these risks during the informed consenting process and adopt preventative strategies into clinical practice to reduce risks where possible. In conclusion, obesity is a significant, modifiable risk factor for increased complications following TKA.

Impact of sarcopenia on rehabilitation outcomes after total knee replacement in older adults with knee osteoarthritis

Introduction:

Knee osteoarthritis (KOA) is associated with an increased risk of sarcopenia, and aging-related muscle deterioration continues after total knee replacement (TKR). Low skeletal muscle mass index may influence postoperative rehabilitation outcomes. Through this study, we aimed to investigate the impact of preoperative sarcopenia on clinical outcomes after postoperative rehabilitation in older Asian adults.

Methods:

A total of 190 older adults (39 men, 151 women) were enrolled from two previous trials and were classified as having no sarcopenia, class I sarcopenia, or class II sarcopenia according to definitions provided by the Asian Working Group for Sarcopenia (AWGS) and the European Working Group on Sarcopenia in Older People (EWGSOP). All patients were retrospectively analyzed before (T₀) and after (T₁) TKR rehabilitation and 10 months after surgery (T₂). The outcome measures included the timed up-and-go test (TUGT), gait speed (GS), timed chair rise (TCR), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and physical difficulty (WOMAC-PF). With patient characteristics and T₀ scores as covariates, an analysis of variance was performed to identify intergroup differences in changes of all outcome measures at T₁ and T₂.

Results:

According to the definitions of both the AWGS and EWGSOP, patients with class I and class II sarcopenia exhibited minor changes in TUGT, GS, TCR, and WOMAC-PF at T₁ and T₂ (all p < 0.05), compared with those without sarcopenia. For patients classified as having sarcopenia based on AWGS and EWGSOP definitions, no significant intergroup differences in WOMAC pain score was observed at T₁ or T₂ (all p > 0.05).

Conclusions:

Sarcopenia independently had negative impacts on the treatment effects of rehabilitation on physical mobility but not on pain outcome after TKR in older adults with KOA.

Hypoalbuminemia and obesity class II are reliable predictors of peri-prosthetic joint infection in patient undergoing elective total knee arthroplasty

Background

Malnutrition is a common and modifiable risk factor for postoperative complications and adverse outcomes in orthopedics. The purpose of this study was to identify biomarkers of malnutrition in patients undergoing elective total knee arthroplasty (TKA) that are predictive of adverse in-hospital postoperative complications, to facilitate the identification of at-risk patients for nutritional optimization before surgery.

Methods

A total of 624 patients who underwent elective TKA between 2013 and 2017 were evaluated; potential biomarkers of preoperative malnutrition, including hypoalbuminemia (serum albumin < 3.5 g/dL), total lymphocyte count (TLC < 1500 cells/mm³), and body mass index (BMI), were assessed for any association with in-hospital postoperative complications.

Results

The prevalence of hypoalbuminemia, low TLC, overweight, obesity class I, and obesity class II were, respectively 2.72%, 33.4%, 14.8%, 44.5%, and 26.9%. There was a significant association between hypoalbuminemia and obesity class II (BMI ≥ 30.0 kg/m²) with rates of peri-prosthetic joint infection, and no significant association between such complications and low TLC, overweight, or obesity class I. Logistic regression analysis showed that patients with hypoalbuminemia or being in obesity class II with gouty arthritis were more likely to suffer from peri-prosthetic joint infection.

Conclusions

Hypoalbuminemia and obesity class II together is a reliable biomarker of preoperative malnutrition for predicting peri-prosthetic joint infection after elective TKA, whereas low TLC, overweight, and obesity class I were not significantly associated with an increased risk of such complications.

Preoperative range of motion and applications of continuous passive motion predict outcomes after knee arthroplasty in patients with arthritis

PURPOSE

This study evaluated the clinical efficacy of continuous passive motion (CPM) following knee arthroplasty and determined the predictors of effect sizes of range of motion (ROM) and functional outcomes in patients with knee arthritis.

METHODS

A comprehensive electronic database search was performed for randomized controlled trials (RCTs), without publication year or language restrictions. The included RCTs were analyzed through meta-analysis and risk of bias assessment. Study methodological quality (MQ) was assessed using the Physiotherapy Evidence Database (PEDro) scale. Inverse-variance weighted univariate and multivariate metaregression analyses were performed to determine the predictors of treatment outcomes.

RESULTS

A total of 77 RCTs with PEDro scores ranging from 6/10 to 8/10 were included. Meta-analyses revealed an overall significant favorable effect of CPM on treatment success rates [odds ratio: 3.64, 95% confidence interval (CI) 2.21-6.00]. Significant immediate [postoperative day 14; standard mean difference (SMD): 1.06; 95% CI 0.61-1.51] and short-term (3-month follow-up; SMD: 0.80; 95% CI 0.45-1.15) effects on knee ROM and a long-term effect on function (12-month follow-up; SMD: 1.08; 95% CI 0.28-1.89) were observed. The preoperative ROM, postoperative day of CPM initiation, daily ROM increment, and total application days were significant independent predictors of CPM efficacy.

CONCLUSION

Early CPM initiation with rapid progress over a long duration of CPM application predicts higher treatment effect on knee ROM and function. The results were based on a moderate level of evidence, with good MQ and potential blinding biases in the included RCTs. An aggressive protocol of CPM has clinically relevant beneficial short-term and long-term effects on postoperative outcomes.

LEVEL OF EVIDENCE

II.

The Effect of Body Mass Index on the Functional Prognosis of Traumatic Brain Injury Patients

BACKGROUND

Although many studies have demonstrated that obesity is correlated with an increased risk of chronic disease, some have reported a paradox by which those in the higher weight categories actually recover better during hospitalization. This study was designed to determine whether this obesity paradox is also reflected in the recovery of patients with traumatic brain injury (TBI) undergoing care in a rehabilitation hospital.

OBJECTIVE

To investigate the association between body mass index (BMI) and the functional progress of patients with TBI, admitted to a rehabilitation hospital.

DESIGN

Retrospective cohort study.

METHODS

The study included all patients admitted to the brain injury unit of a rehabilitation hospital over a 6-year period. The data used for this study included patient height and weight (measured on admission) and functional independence measurements (scored on admission and discharge).

MAIN OUTCOME MEASURES

Functional independence measure (FIM) change per day, BMI category.

RESULTS

For the 444 patients admitted, the overall FIM efficiency did not differ significantly by BMI (P = .93). After adjusting for age and gender, overweight and obese patients had the lowest FIM efficiency (1.04 for both groups), followed by the underweight and normal weight groups (1.11 and 1.26, respectively).

CONCLUSION

This study demonstrated that higher BMI was not significantly correlated with the rate of functional recovery among patients admitted to a rehabilitation hospital for TBI.

LEVEL OF EVIDENCE

III.

Body mass index changes after unicompartmental knee arthroplasty do not adversely influence patient outcomes

PURPOSE

The objective of this study is to evaluate the prevalence of patients who lost or gained weight following unicompartmental knee arthroplasty (UKA), the effect of post-operative body mass index (BMI) changes on functional outcomes and quality of life (QoL), and predictive factors associated with BMI changes.

METHODS

Prospectively collected data of 1043 patients who underwent UKA between 2000 and 2014 were reviewed. BMI, Knee Society Knee Score and Function Score, Oxford Knee Score (OKS), Short-Form 36 (SF-36) Physical Component Score (PCS) and Mental Component Score and proportion of patients attaining OKS/SF-36 minimal clinically important differences (MCID) were recorded preoperatively and at 2 years post-operatively. The patients were stratified into three groups based on weight changes for further analysis.

RESULTS

Following UKA, 138 (13.3%) patients had lost weight, 695 (66.6%) maintained their weight, and 210 (20.1%) gained weight. Patients in all groups demonstrated significant improvements in functional and SF-36 PCS scores at 2 years post-operatively. There were no significant differences in functional outcomes, QoL or revision rate between the groups. Post-operative BMI changes were not correlated with any outcome scores or attainment of MCID (n.s.).

CONCLUSIONS

This is the first study that evaluates change in BMI following UKA. It demonstrated a higher proportion of patients who gained weight as compared to those who lost weight. Post-operative BMI changes did not appear to affect outcomes of UKA. These findings will provide important information to surgeons when counselling patients regarding BMI change and its effect on outcomes after UKA.

LEVELS OF EVIDENCE

Level III.

WHO Class of Obesity Influences Functional Recovery Post-TKA

BACKGROUND

No study in the literature has compared early functional recovery following total knee arthroplasty (TKA) in the obese with the nonobese using World Health Organization (WHO) classes of obesity. Our aim was to compare functional scores and flexion post-TKA in each class of obesity as per WHO classification against a matched control group of nonobese patients.

METHODS

Records of 885 consecutive primary TKA patients (919 knees) operated by a single surgeon were reviewed. The first 35 knees in each class I, class II and class III obesity group during the study period were then matched with a similar number of knees in nonobese TKA patients during the same period. Functional scores recorded pre- and postoperatively at 3 months and 1 year were Western Ontario and McMaster Osteoarthritis Index (WOMAC), Short-Form Health Survey (SF-12) score, and Knee Society Score (KSS).

RESULTS

There was no difference in any parameter between the class I obese and matched nonobese at any assessment point. In the class II obese, as compared to the nonobese, there was no difference in any parameter preoperatively and 3 months postoperatively. However, 1 year postoperatively, the SF-12 physical subscore was lower in the class II obese than the nonobese (44.7 vs. 48.6, p = 0.047) and the WOMAC score was significantly higher (15.8 vs. 9.7, p = 0.04). In the class III obese, the WOMAC score was significantly higher than the nonobese (58.1 vs. 44.3, p < 0.001 preoperatively; 15.7 vs. 8.1, p = 0.005 at 1 year) and KSS was significantly lower (83.5 vs. 96.5, p = 0.049 preoperatively; 172 vs. 185; p = 0.003 at 1 year). Knee flexion was significantly lower in the class III obese than the nonobese (95 vs. 113; p < 0.001 preoperatively; 120 vs. 127; p = 0.002 at 1 year).

CONCLUSIONS

The class I obese can expect good early and late functional recovery as the nonobese. The class II obese can expect comparable early functional recovery as the nonobese but their late function may be lesser. The class III obese would have poorer functional scores and lesser knee flexion postoperatively compared to the nonobese. However, compared to their own preoperative status, there is definite improvement in function and knee flexion.

Physical Function After Total Knee Replacement: An Observational Study Describing Outcomes in a Small Group of Women From China and the United States

OBJECTIVE

To describe physical function before and six months after Total Knee Replacement (TKR) in a small sample of women from China and the United States.

DESIGN

Observational.

SETTING

Community environment.

OUTCOMES

Both groups adhered to the Osteoarthritis Research Society International (OARSI) protocols for the 6-minute walk and 30-second chair stand. We compared physical function prior to TKR and 6 months after using linear regression adjusted for covariates.

PARTICIPANTS

Women (N=60) after TKR.

INTERVENTIONS

Not applicable.

RESULTS

Age and body mass index in the China group (n=30; 66y and 27.0kg/m²) were similar to those in the U.S. group (n=30; 65y and 29.6kg/m²). Before surgery, the China group walked 263 (95% confidence interval [CI], -309 to -219) less meters and had 10.2 (95% CI, -11.8 to -8.5) fewer chair stands than the U.S. group. At 6 months when compared with the U.S. group, the China group walked 38 more meters, but this difference did not reach statistical significance (95% CI, -1.6 to 77.4), and had 3.1 (95% CI, -4.4 to -1.7) fewer chair stands. The China group had greater improvement in the 6-minute walk test than did the U.S. group (P<.001).

CONCLUSIONS

Despite having worse physical function before TKR, the China group had greater gains in walking endurance and similar gains in repeated chair stands than did the U.S. group after surgery.

Association of anterior cruciate ligament injury with knee osteoarthritis and total knee replacement: A retrospective cohort study from the Taiwan National Health Insurance Database

Objective

This study aimed to support the potential protective role of anterior cruciate ligament (ACL) reconstruction against the development of osteoarthritis (OA).

Methods

In this retrospective cohort study, the long-term results of ACL reconstruction in Taiwan were evaluated based on data from the National Health Insurance Research Database (NHIRD). In total, 8,769 eligible cases were included from 11,921 ACL-injured patients. The cumulative incidence rates of OA and total knee replacement (TKR) were analyzed using the Kaplan-Meier estimator. Cox proportional hazards models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of OA.

Results

There was a lower cumulative incidence of OA among ACL-reconstructed patients (271, 33.1%) than among non-reconstructed patients (1,874, 40.3%; p < 0.001). Patients who underwent ACL reconstruction had a lower cumulative incidence of TKR during the follow-up period (0.6%) than the non-reconstructed patients (4.6%, p < 0.001). After adjusting for covariates, ACL-injured patients who underwent reconstruction within one month after ACL injury showed a significantly lower risk of OA than those who never underwent reconstruction (adjusted HR = 0.83, 95% CI = 0.69–0.99).

Conclusions

These results indicate that ACL reconstruction might not provide complete protection from OA development after traumatic knee injury but does yield a lower cumulative incidence of OA development and TKR. Moreover, based on the present study, ACL-injured patients should undergo reconstruction as early as possible (within one month) to lower the risk of OA.

The Role of Patient Characteristics on the Choice of Unicompartmental versus Total Knee Arthroplasty in Patients With Medial Osteoarthritis

BACKGROUND

Medial unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are both viable treatment options for medial osteoarthritis (OA). However, it remains unclear when to choose for which arthroplasty treatment. Goals of this study were therefore to (1) compare outcomes after both treatments and (2) assess which treatment has superior outcomes in different patient subgroups.

METHODS

In this retrospective cohort study, 166 patients received the RESTORIS MCK Medial UKA and 63 patients the Vanguard TKA and were radiographically matched on isolated medial OA. Western Ontario and McMaster Universities Arthritis Index scores were collected preoperatively and postoperatively (mean: 3.0 years, range: 2.0-5.0 years).

RESULTS

Preoperatively, no differences were observed, but medial UKA patients reported better functional outcomes than TKA (89.7 ± 13.6 vs 81.2 ± 18.0, P = .001) at follow-up.Better functional outcomes were noted after medial UKA in patients younger than age 70 years (89.5 ± 14.2 vs 78.6 ± 20.0, P = .001), with body mass index below 30 (90.3 ± 11.4 vs 83.6 ± 14.9, P = .005), with body mass index above 30 (88.3 ± 17.5 vs 78.8 ± 21.0, P = .034) and in females (90.6 ± 11.0 vs 78.1 ± 19.4, P = .001) when compared with TKA. No differences were found in males and older patients between both arthroplasties.

CONCLUSION

Superior functional outcomes were noted after medial UKA over TKA in patients presenting with medial OA with these prostheses. Subgroup analyses suggest that medial UKA is the preferred treatment in younger patients and females while no differences were noted in older patients and males after medial UKA and TKA. This might help the orthopedic surgeon in individualizing arthroplasty treatment for patients with medial OA.

Patients with isolated lateral osteoarthritis: Unicompartmental or total knee arthroplasty?

BACKGROUND

Lateral unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are both reliable treatment options for patients with isolated lateral osteoarthritis (OA). However, studies comparing both procedures are scarce. Aims of this study were to (I) compare short-term functional outcomes following lateral UKA and TKA and (II) assess the role of patient characteristics on outcomes as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

METHODS

In this retrospective cohort study, 82 patients (48 undergoing lateral UKA and 34 undergoing TKA) were identified that presented with lateral OA and completed the WOMAC. Independent t-tests were used to compare outcomes following lateral UKA and TKA.

RESULTS

Mean follow-up was 2.8 years (range: 2.0 - 5.0 years). Preoperatively, no differences between lateral UKA and TKA were seen (50.1±13.5 and 53.3±17.1, respectively, p=0.551). Postoperatively, lateral UKA patients reported better overall outcomes than TKA (90.5±11.7 vs. 81.8±17.9, p=0.017). Subgroup analysis showed better outcomes following lateral UKA than TKA in patients younger than 75 years (92.1±9.9 vs. 81.3±19.6, p=0.014) and in females (91.6±9.9 vs. 81.0±18.2, p=0.014).

CONCLUSION

These findings indicate that lateral UKA has superior short-term functional outcomes compared to TKA in patients with isolated lateral OA. Better outcomes were especially seen in younger patients and females. These findings may help orthopedic surgeons choose treatment for patients presenting with lateral OA and optimize treatment for individual patients.

Effect of body mass index on knee function outcomes following continuous passive motion in patients with osteoarthritis after total knee replacement: a retrospective study

OBJECTIVE

Obesity may influence postoperative rehabilitation outcomes after total knee replacement (TKR). The aim of this study was to evaluate the effects of body mass index (BMI) on the progression of inpatient rehabilitation using continuous passive motion (CPM) and its treatment outcomes.

PARTICIPANTS AND SETTING

A retrospective study was conducted in a rehabilitation centre. In total, 354 patients undergoing primary TKR were enrolled through medical chart review.

INTERVENTION

All patients commenced the CPM programme immediately after surgery and continued until hospital discharge.

MAIN OUTCOME MEASURES

Knee flexion, pain score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function score.

DESIGN

Patients were divided into five BMI groups: normal weight (n=59), overweight (n=95), Class I obesity (n=90), Class II obesity (n=82) and Class III obesity (n=28). All outcome measures were recorded at admission; daily during the inpatient stay; at discharge; and at 1-, 3- and 6-month follow-up assessments.

RESULTS

During CPM exercises, obese patients had a smaller initial flexion angle (P<0.001) and a smaller daily increment in the CPM motion arc (P<0.001) compared with patients of normal weight. Severe obesity was associated with poor knee flexion [adjusted odds ratio (aOR) 11.9, 95% confidence interval (CI) 3.49 to 40.94, P<0.001] and WOMAC physical function score (aOR 5.09, 95% CI 1.62 to 16.03, P=0.005) at 6-month follow-up.

CONCLUSIONS

Obesity had a negative effect on progress during the CPM protocol, which commenced immediately after surgery and continued until discharge. Obesity was also associated with poorer self-reported function at 6-month follow-up.