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

Postoperative Continuous Passive Motion Does Not Improve the Range of Movement Achieved After Manipulation Under Anesthetic for Stiffness in Total Knee Replacement

Background

Stiffness is a common complication following total knee arthroplasty. Manipulation under anesthesia (MUA) is an intervention that can potentially improve range of motion (ROM). Continuous passive motion (CPM) therapy has been utilized to enhance post-MUA ROM, but its effectiveness remains debated. This study assesses whether CPM therapy after MUA results in superior ROM outcomes compared to MUA alone.

Methods

A retrospective analysis included patients undergoing MUA for stiff primary total knee arthroplasty between 2017 and 2022. Demographics and ROM data were collected. Patients were in 2 groups: those who received inpatient CPM post-MUA and those who received day-case MUA alone. Complications and further interventions were noted.

Results

Of 126 patients, 39 underwent MUA only (day-case group), and 87 received CPM and MUA (inpatient group). Mean preoperative ROM was 69.4° (standard deviation [SD]:18.0°) and 73.9° (SD: 18.1°) for inpatient and day-case groups, respectively. Mean post-MUA ROM improved by 39.4° (SD: 17.7°) and 25.5° (SD: 11.1°) inpatient groups and day-case, respectively. The mean percentage of ROM gained at MUA maintained at final follow-up was 63.7% (40.8%) and 67.0% (47.5%) inpatient and day-case groups, respectively.

Conclusions

This study found no advantage in the routine use of CPM post-MUA for stiff total knee replacement patients, suggesting it may not provide sustained ROM improvements compared to MUA alone. Cost-effectiveness and patient selection merit further investigation.

Effects of a Hybrid Teaching Program on Lower Limb Muscle Strength, Knee Function, and Depression in Older Adults After Total Knee Replacement: A Randomized Controlled Trial

The aim of the current study was to evaluate the effects of a nurse-led hybrid teaching program on lower limb strength, knee function, and depression in older adults after total knee replacement (TKR). This was a single-blind, randomized controlled trial. Fifty-two patients who underwent TKR were randomly assigned to either the experimental group (EG; n = 26), which received routine care plus 16 weeks of home rehabilitation through a hybrid teaching program, or the control group (CG; n = 26), which received routine care only. The intervention included pre-discharge face-to-face education, video instructions to follow at home after discharge, and four monthly telephone-based follow ups during the 16 weeks post-surgery. After the 16-week intervention, participants in the EG exhibited improved quadriceps strength, hamstring strength, and Knee Injury and Osteoarthritis Outcome Score (KOOS) compared to those in the CG. Generalized estimating equation analyses revealed a significant group-by-time interaction effect on quadriceps strength, overall KOOS score, and Geriatric Depression Scale-Short Form score. Findings suggest that a nurse-led hybrid teaching program enhances physical and psychological function after TKR when compared to routine care. This hybrid teaching program, involving exercise and postoperative education, proves to be a feasible and cost-effective intervention for improving outcomes in older adults following TKR. Health care teams should consider it as a viable home rehabilitation option for older adults who undergo TKR. [Research in Gerontological Nursing, 17(1), 31-40.].

Medial Patellofemoral Ligament Reconstruction in Obese Patients Results in Low Complication Rates and Improved Subjective Outcomes

Purpose

To compare outcomes, activity scores, and complication rates of obese and non-obese patients undergoing medial patellofemoral ligament (MPFL) reconstruction.

Methods

A retrospective review identified patients undergoing MPFL reconstruction for recurrent patellofemoral instability. Patients were included if they had undergone MPFL reconstruction and had follow-up for a minimum of 6 months. Patients were excluded if they underwent surgery less than 6 months earlier, had no outcome data recorded, or underwent concomitant bony procedures. Patients were divided into 2 groups based on body mass index (BMI): BMI of 30 or greater and BMI less than 30. Presurgical and postsurgical patient-reported outcomes including Knee Injury and Osteoarthritis Outcome Score (KOOS) domains and the Tegner score were collected. Complications requiring reoperation were recorded. P < .05 was defined as a statistically significant difference.

Results

A total of 55 patients (57 knees) were included. There were 26 knees with a BMI of 30 or greater and 31 knees with a BMI less than 30. There were no differences in patient demographic characteristics between the 2 groups. Preoperatively, no significant differences were found in KOOS subscores or Tegner scores (P = .21) between groups. At minimum 6-month follow-up (range, 6.1-70.5 months), patients with a BMI of 30 or greater showed statistically significant improvements in the KOOS Pain, Activities of Daily Living, Symptoms, and Sport/Recreation subscores. Patients with a BMI less than 30 showed a statistically significant improvement in the KOOS Quality of Life subscore. The group with a BMI of 30 or greater had significantly lower KOOS Quality of Life (33.34 ± 19.10 vs 54.47 ± 28.00, P = .03) and Tegner (2.56 ± 1.59 vs 4.78 ± 2.68, P = .05) scores. Complication rates were low, with 2 knees (7.69%) requiring reoperation in the cohort with a BMI of 30 or greater and 4 knees (12.90%) requiring reoperation in the cohort with a BMI less than 30, including 1 reoperation for recurrent patellofemoral instability (P = .68).

Conclusions

In this study, MPFL reconstruction in obese patients was safe and effective, with low complication rates and improvements in most patient-reported outcomes. Compared with patients with a BMI less than 30, obese patients had lower quality-of-life and activity scores at final follow-up.

Level of Evidence

Level III, retrospective cohort study.

Long-Term Postoperative Total Knee Arthroplasty Flexion Scores in Relation to Body Mass Index

Knee range of motion (ROM) is an important postoperative measure of total knee arthroplasty (TKA). There is conflicting literature whether patients who are obese have worse absolute ROM outcomes than patients who are not obese. This study analyzed whether preoperative body mass index (BMI) influences knee ROM after patients' primary TKA. A retrospective investigation was performed on patients, who underwent primary TKA at an academic institution, by one of three fellowship-trained adult reconstruction surgeons. Patients were stratified according to their preoperative BMI into nonobese (BMI < 30.0 kg/m²) and obese (BMI ≥ 30.0 kg/m²) classifications. Passive ROM was assessed preoperatively as well as postoperatively at patients' most recent follow-up visit that was greater than 2 years. Mann-Whitney U tests were performed to determine statistical significance at p-value <0.05 for ROM outcomes. No statistically significant differences were observed when ROM in the nonobese group was compared with ROM in the obese group both preoperatively (105.73 ± 11.58 vs. 104.14 ± 13.58 degrees, p-value = 0.417) and postoperatively (105.83 ± 14.19 vs. 104.49 ± 13.52 degrees, p-value = 0.777). Mean follow-up time for all patients was 4.49 ± 1.92 years. In conclusion, long-term postoperative ROM outcomes were similar between patients who were nonobese and patients who were obese.

Machine learning approach to predicting persistent opioid use following lower extremity joint arthroplasty

Background

The objective of this study is to develop predictive models for persistent opioid use following lower extremity joint arthroplasty and determine if ensemble learning and an oversampling technique may improve model performance.

Methods

We compared various predictive models to identify at-risk patients for persistent postoperative opioid use using various preoperative, intraoperative, and postoperative data, including surgical procedure, patient demographics/characteristics, past surgical history, opioid use history, comorbidities, lifestyle habits, anesthesia details, and postoperative hospital course. Six classification models were evaluated: logistic regression, random forest classifier, simple-feedforward neural network, balanced random forest classifier, balanced bagging classifier, and support vector classifier. Performance with Synthetic Minority Oversampling Technique (SMOTE) was also evaluated. Repeated stratified k-fold cross-validation was implemented to calculate F1-scores and area under the receiver operating characteristics curve (AUC).

Results

There were 1042 patients undergoing elective knee or hip arthroplasty in which 242 (23.2%) reported persistent opioid use. Without SMOTE, the logistic regression model has an F1 score of 0.47 and an AUC of 0.79. All ensemble methods performed better, with the balanced bagging classifier having an F1 score of 0.80 and an AUC of 0.94. SMOTE improved performance of all models based on F1 score. Specifically, performance of the balanced bagging classifier improved to an F1 score of 0.84 and an AUC of 0.96. The features with the highest importance in the balanced bagging model were postoperative day 1 opioid use, body mass index, age, preoperative opioid use, prescribed opioids at discharge, and hospital length of stay.

Conclusions

Ensemble learning can dramatically improve predictive models for persistent opioid use. Accurate and early identification of high-risk patients can play a role in clinical decision making and early optimization with personalized interventions.

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.

Shape is only a weak predictor of deep knee flexion kinematics in healthy and osteoarthritic knees

Tibiofemoral shape influences knee kinematics but little is known about the effect of shape on deep knee flexion kinematics. The aim of this study was to examine the association between tibiofemoral joint shape and kinematics during deep kneeling in patients with and without osteoarthritis (OA). Sixty-one healthy participants and 58 patients with end-stage knee OA received a computed tomography (CT) of their knee. Participants completed full flexion kneeling while being imaged using single-plane fluoroscopy. Six-degree-of-freedom kinematics were measured by registering a three-dimensional (3D)-static CT onto 2D-dynamic fluoroscopic images. Statistical shape modeling and bivariate functional principal component analysis (bfPCA) were used to describe variability in knee shape and kinematics, respectively. Random-forest-regression models were created to test the ability of shape to predict kinematics controlling for body mass index, sex, and group. The first seven modes of the shape model up to three modes of the bfPCAs captured more than 90% of the variation. The ability of the random forest models to predict kinematics from shape was low, with no more than 50% of the variation being explained in any model. Furthermore, prediction errors were high, ranging between 24.2% and 29.4% of the data. Variations in the bony morphology of the tibiofemoral joint were weakly associated with the kinematics of deep knee flexion. The models only explained a small amount of variation in the data with high error rates indicating that additional predictors need to be identified. These results contribute to the clinical understanding of knee kinematics and potentially the expectations placed on high-flexion total knee replacement design.

Effects of Elastic Resistance Exercise on Postoperative Outcomes Linked to the ICF Core Sets for Osteoarthritis after Total Knee Replacement in Overweight and Obese Older Women with Sarcopenia Risk: A Randomized Controlled Trial

(1) Background: Knee osteoarthritis (KOA) and aging are associated with high sarcopenia risk; sarcopenia may further affect outcomes after total knee replacement (TKR). Elastic resistance exercise training (RET) limits muscle attenuation in older adults. We aimed to identify the effects of post-TKR elastic RET on lean mass (LM) and functional outcomes in overweight and obese older women with KOA by using the brief International Classification of Functioning, Disability and Health Core Set for osteoarthritis (Brief-ICF-OA). (2) Methods: Eligible women aged ≥60 years who had received unilateral primary TKR were randomly divided into an experimental group (EG), which received postoperative RET twice weekly for 12 weeks, and a control group (CG), which received standard care. The primary and secondary outcome measures were LM and physical capacity, respectively, and were linked to the Brief-ICF-OA. The assessment time points were 2 weeks prior to surgery (T₀) and postoperative at 1 month (T₁; before RET) and 4 months (T₂; upon completion of RET) of follow-up. An independent t test with an intention-to-treat analysis was conducted to determine the between-group differences in changes of outcome measures at T₁ and T₂ from T₀. (3) Results: Forty patients (age: 70.9 ± 7.3 years) were randomly assigned to the EG (n = 20) or CG (n = 20). At T₂, the EG exhibited significantly greater improvements in leg LM (mean difference (MD) = 0.86 kg, p = 0.004) and gait speed (MD = 0.26 m/s, p = 0.005) compared with the CG. Furthermore, the EG generally obtained significantly higher odds ratios than the CG for treatment success for most Brief-ICF-OA categories (all p < 0.001). Conclusions: Early intervention of elastic RET after TKR yielded positive postoperative outcomes based on the Brief-ICF-OA. The findings of this study may facilitate clinical decision-making regarding the optimal post-TKR rehabilitation strategy for older women with KOA.

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.

Can Early Rehabilitation Prevent Posttraumatic Osteoarthritis in the Patellofemoral Joint after Anterior Cruciate Ligament Rupture? Understanding the Pathological Features

Knee instability resulting from anterior cruciate ligament (ACL) rupture is a high-risk factor for posttraumatic osteoarthritis (PTOA) in the patellofemoral joint (PFJ). However, whether non-weight-bearing and weight-bearing treatments have chondroprotective effects remains unclear. Twenty-four adult New Zealand White male rabbits were employed in this study. All animals received ACL transection in the right knee and sham surgery in the left knee. The rabbits were randomly assigned to the following groups: (I) In the sedentary (SED) group, the rabbits (n = 6) were simply kept in their cage; (II) In the continuous passive motion (CPM) group, the rabbits (n = 6) performed CPM exercise for 7 days, starting from the first postoperative day; (III) In the active treadmill exercise (TRE) group, the rabbits (n = 6) performed TRE for 2 weeks; (IV) In the CPM + TRE group, the rabbits (n = 6) executed CPM exercise, followed by TRE. Two joint surfaces (the retropatella and femoral trochlear groove) were assessed at 4 weeks after operation. Although the gross appearance in each group was comparable, histological examination revealed significant differences in the articular cartilage status. The CPM group exhibited a greater thickness of articular cartilage, maintenance of tidemark continuity, abundant glycosaminoglycan (GAG), and significantly lower inflammatory cytokine 9, e.g., tumor necrosis factor-alpha (TNF-α) 0 levels, with modest cell apoptosis (i.e., caspase-3). By contrast, the TRE group displayed the worst pathological features: an irregular cartilage surface and chondrocyte disorganization, reduced cartilage thickness, breakdown of the tidemark, depletion of collagen fibers, loss of GAG, and the highest levels of TNF-α and caspase-3 expression. Furthermore, the CPM + TRE group had more favorable outcomes than the SED group, indicating that suitable exercise is needed. The sham treatment displayed no variance in the changes in the two joint surfaces among groups. These data indicate that the application of early CPM rehabilitation is suggested for subjects in order to decrease the risk of PTOA without ACL reconstruction in the PFJ compartment in rabbits. The early TRE program, however, had harmful outcomes. Additionally, inactivity was discovered to initiate the development of PTOA.