Lower limb strength following total knee arthroplasty: a systematic review

Efficiency assessment of follow-up methodology of patients with knee replacement to predict post-surgical functionality: a protocol for randomised control PROKnee trial

INTRODUCTION

Even when total knee arthroplasty (TKA) is an extended treatment, most patients experience a suboptimal evolution after TKA. The objectives of this study are the following: (1) to determine the effectiveness of two different prosthesis stabilisation systems on the functionality in activities of daily life, and (2) to determine prognostic biomarkers of knee prosthesis function based on radiological information, quantification of cytokines, intra-articular markers and biomechanical functional evaluation to predict successful evolution.

METHODS AND ANALYSIS

The PROKnee trial was designed as a randomised controlled patient-blinded trial with two parallel groups that are currently ongoing. The initial recruitment will be 99 patients scheduled for their first TKA, without previous prosthesis interventions in lower limbs, who will be randomly divided into two groups that differed in the stabilisation methodology incorporated in the knee prosthesis: the MEDIAL-pivot group and the CENTRAL-pivot group. The maximum walking speed will be reported as the primary outcome, and the secondary results will be patient-reported questionnaires related to physical status, cognitive and mental state, radiological test, laboratory analysis and biomechanical instrumented functional performance, such as the 6-minute walking test, timed up-and-go test, gait, sit-to-stand, step-over, and ability to step up and down stairs. All the results will be measured 1 week before TKA and at 1.5, 3, 6 and 12 months after surgery.

ETHICS AND DISSEMINATION

All procedures were approved by the Ethical Committee for Research with Medicines of the University Clinical Hospital of Valencia on 8 October 2020 (order no. 2020/181). Participants are required to provide informed consent for the study and for the surgical procedure. All the data collected will be treated confidentially since they will be blinded and encrypted. The results from the trial will be published in international peer-reviewed scientific journals, regardless of whether these results are negative or inconclusive.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04850300).

Responsiveness of Isokinetic Dynamometry in Patients with Osteoarthritis after Knee and Hip Arthroplasty: A Prospective Repeated-Measures Cohort Study

Functional assessments are crucial for the evaluation of rehabilitation after total knee (TKA) and hip (THA) arthroplasty. Muscle strength, a key determinant of physical function (PF), is often measured with isokinetic dynamometry (ID), which is considered the gold standard. However, studies lack evaluations of responsiveness-the ability to detect changes over time. This study aims to determine the responsiveness of ID in measuring PF in TKA and THA rehabilitation-is muscle strength a valid indicator for assessing improvement in rehabilitation processes? The pre- and post-surgery PF of 20 osteoarthritis patients (age 55-82) was assessed, using ID, performance-based and self-reported measures. Responsiveness was evaluated by comparing the observed relationship of changes in ID and PF scores with the a priori defined expected relationship of change scores. While the performance-based and self-reported measures showed significant improvements post-surgery (Cohen's d [0.42, 1.05] p < 0.05), ID showed no significant differences. Moderate correlations were found between changes in some ID parameters and selected functional tests (r ≈|0.5|, p < 0.05). Responsiveness was solely found for the peak torque of knee extension at 180°/s on the operated side. Responsiveness is an often-overlooked psychometric property of outcome measurements. The findings suggest that ID may not be fully responsive to the construct of PF after TKA and THA, raising questions about its role and usefulness in this context and the need for more appropriate assessment methods.

Abnormal gait pattern in downhill hiking is related to muscular deficits of the knee flexors and extensors in active patients with total knee arthroplasty

BACKGROUND

To assess the in-field walking mechanics during downhill hiking of patients with total knee arthroplasty five to 14 months after surgery and an age-matched healthy control group and relate them to the knee flexor and extensor muscle strength.

METHODS

Participants walked on a predetermined hiking trail at a self-selected, comfortable pace wearing an inertial sensor system for recording the whole-body 3D kinematics. Sagittal plane hip, knee, and ankle joint angles were evaluated over the gait cycle at level walking and two different negative slopes. The concentric and eccentric lower extremity muscle strength of the knee flexors and extensors isokinetically at 50 and 120°/s were measured.

FINDINGS

Less knee flexion angles during stance have been measured in patients in the operated limb compared to healthy controls in all conditions (level walking, moderate downhill, steep downhill). The differences increased with steepness. Muscle strength was lower in patients for both muscle groups and all measured conditions. The functional hamstrings to quadriceps ratio at 120°/sec correlated with knee angle during level and downhill walking at the moderate slope in patients, showing higher ratios with lower peak knee flexion angles.

INTERPRETATION

The study shows that even if rehabilitation has been completed successfully and complication-free, five to 14 months after surgery, the muscular condition was still insufficient to display a normal gait pattern during downhill hiking. The muscle balance between quadriceps and hamstring muscles seems related to the persistence of a stiff knee gait pattern after knee arthroplasty. LoE: III.

Hip abduction angle after open-wedge high tibial osteotomy is associated with the timed up & go test and recurrence of varus alignment

The aim of this study is to investigate the association between the hip abduction angle (HAA) and lower limb alignment as well as the clinical assessments in open-wedge high tibial osteotomy (OWHTO) patients. A total of 90 patients who underwent OWHTO were included. The demographic characteristics and clinical assessments (the Visual Analogue Scale for activities of daily living, the Japanese knee osteoarthritis measure, the Knee injury and Osteoarthritis Outcome Score, the Knee Society score, the Timed Up & Go (TUG) test, the single standing (SLS) test and muscle strength) were recorded. The patients were divided into two groups according to the HAA at 1 month after operation: the HAA (-) group (HAA < 0°) and the HAA (+) group (HAA ≥ 0°). Clinical scores except for the SLS test and radiographic parameters except for the posterior tibia slope (PTS), lateral distal femoral angle (LDFA) and lateral distal tibial angle (LDTA) were significantly improved at 2 years postoperatively. Regarding the two groups, scores on the TUG test in the HAA (-) group were significantly lower than those in the HAA (+) group (p = 0.011). The hip-knee-ankle angle (HKA), weight bearing line (WBLR) and knee joint line obliquity (KJLO) in the HAA (-) group were significantly higher than those in the HAA (+) group (p < 0.001, 0.001 and p = 0.025). In contrast, the LDFA in the HAA (-) group were significantly lower than those in the HAA (+) group (p < 0.001). The TUG test and the LDFA were weakly positively correlated with the HAA (r = 0.34, 0.42, p < 0.001 and 0.001). In contrast, the HKA, WBLR and KJLO had a weak negative correlation with the HAA (r = - 0.43, - 0.38 and - 0.37, p < 0.001, 0.001 and 0.001). This study showed the postoperative HAA was significantly associated with the TUG test and the HKA, WBLR, LDFA, and KJLO. A higher postoperative HAA might induce varus recurrence and poor outcomes of the gait parameter.

Knee Loading With Blood Flow Restriction Can Enhance Recovery After Total Knee Arthroplasty

Total knee arthroplasty (TKA) is one of the most performed operations in the world, especially in the elderly. Aging has a significant effect on joint cartilage, muscle strength, and muscle mass. Following a TKA, despite the significant reduction of symptoms and the improvement in mobility, muscle strength and muscle mass recovery remains a significant challenge. Restrictions that arise from the surgical procedure include joint loading, functional activities, and range of motion, along with limitations related to the age of the individual and their previous loading history, these are the significant restrictions, at least in the early stages of rehabilitation. Evidence indicates that blood flow restriction (BFR) training has significant potential to enhance recovery via implementation of low-load or low-intensity exercise. While respecting the indications and contraindications related to BFR application, the optimization of metabolic stress seems to offer a bridging therapy to heavy load while reducing pain and inflammation. Thus, the combination of BFR and low loads may improve muscular recovery (strength and mass), and aerobic training protocols appear to show significant enhancement of multiple cardiopulmonary parameters. Mounting evidence, direct and indirect, indicate that BFR training may have the potential to benefit the pre-operative and post-operative TKA rehabilitation phases and enhance functional recovery and physical abilities in the elderly.

The course of knee extensor strength after total knee arthroplasty: a systematic review with meta-analysis and -regression

PURPOSE

Muscular strength loss and atrophy are postoperative complications. This systematic review with meta-analysis investigated the course of on knee extensor mass and strength from pre-surgery over total knee arthroplasty to rehabilitation and recovery.

METHODS

A systematic literature search was conducted in PubMed (Medline), Cochrane Library (CINAHL, Embase) and Web of Science (until 29th of June 2022). Main inclusion criteria were  ≥ 1 preoperative and  ≥ 1 measurement  ≥ 3-months post-operation and ≥ 1 objective assessment of quadriceps strength, muscle mass or neuromuscular activity, measured at both legs. Studies were excluded if they met the following criteria: further impairment of treated extremity or of the contralateral extremity; further muscle affecting disease, or muscle- or rehabilitation-specific intervention. The Robins-I tool for non-randomized studies, and the Cochrane Rob 2 tool for randomized controlled studies were used for risk of bias rating. Pre-surgery, 3 months, 6 months and 1 year after surgery data were pooled using random effects meta-analyses (standardized mean differences, SMD, Hedge's g) in contrast to the pre-injury values.

RESULTS

1417 studies were screened, 21 studies on 647 participants were included. Thereof, 13 were non-randomized controlled trails (moderate overall risk of bias in most studies) and 7 were randomized controlled trials (high risk of bias in at least one domain in most studies). Three (k = 12 studies; SMD = - 0.21 [95% confidence interval = - 0.36 to - 0.05], I² = 4.75%) and six (k = 9; SMD = - 0.10 [- 0.28 to - 0.08]; I² = 0%) months after total knee arthroplasty, a deterioration in the strength of the operated leg compared with the strength of the non-operated leg was observed. One year after surgery, the operated leg was stronger in all studies compared to the preoperative values. However, this increase in strength was not significant compared to the non-operated leg (k = 6, SMD = 0.18 [- 0.18 to 0.54], I² = 77.56%).

CONCLUSION

We found moderate certainty evidence that deficits in muscle strength of the knee extensors persist and progress until 3 months post-total knee arthroplasty in patients with end-stage knee osteoarthritis. Very low certainty evidence exists that preoperatively existing imbalance of muscle strength and mass in favor of the leg not undergoing surgery is not recovered within 1 year after surgery.

Development of reference charts for monitoring quadriceps strength with handheld dynamometry after total knee arthroplasty

Purpose: To develop reference charts that describe normative quadriceps strength recovery after total knee arthroplasty (TKA) as measured by handheld dynamometry (HHD).Materials and Methods: We conducted a retrospective analysis of post-TKA quadriceps strength recovery in a longitudinal dataset consisting of both clinical and research HHD data. We created sex-specific models for recovery using Generalized Additive Models for Location, Scale, and Shape. We created reference charts from the models to display the recovery of population centiles over the first six postoperative months.Results: A total of 588 patient records with 1176 observations were analyzed. Reference charts for both sexes demonstrated a rapid increase in quadriceps strength over the first 60 postoperative days followed by a more gradual increase over the next 120 days. Males appeared to demonstrate faster recovery and greater strength on average compared to females. The quadriceps strength recovery of three female patient records was plotted on the reference chart to illustrate the charts' potential clinical utility.Conclusions: These reference charts provide normative data for quadriceps strength recovery after TKA as assessed by HHD. The reference charts may augment clinicians' ability to monitor and intervene upon quadriceps weakness-a pronounced and debilitating post-TKA impairment-throughout rehabilitation.Implications for RehabilitationHandheld dynamometry (HHD) is an objective and clinically feasible method for assessing muscle strength, but normative HHD values are lacking for quadriceps strength recovery after total knee arthroplasty (TKA).We created sex-specific reference charts which provide normative quadriceps strength HHD values for the first 180 days after TKA.These reference charts may improve clinicians' ability to monitor and intervene upon post-TKA quadriceps strength deficits.

The validity and reliability of the OneStep smartphone application under various gait conditions in healthy adults with feasibility in clinical practice

Objective

Primary purpose of this study was to determine the validity and reliability of the OneStep smartphone application in healthy adults. Secondary purpose was to determine the feasibility of measuring gait dysfunction, limitation in spatiotemporal characteristics, longitudinally in patients following total hip or knee arthroplasty.

Methods

First objective, 20 healthy adults (mean age, 42.3 ± 19.7 years; 60% males; mean body mass index, 29.0 ± 5.2 kg/m²) underwent gait analysis under four gait conditions (self-selected gait speed, fixed gait speed at 0.8 m/s, fixed gait speed at 2.0 m/s and self-selected gait speed with dual task) for the validity and reliability of the smartphone to the motion laboratory. Reliability was determined by intraclass correlation coefficients. Validity was determined by Pearson correlations. Agreement was assessed by the Bland–Altman method. Second objective, 12 additional patients with total hip or knee arthroplasty (mean age, 58.7 ± 6.5 years; 58% males; mean body mass index, 28.9 ± 5.8 kg/m²) were measured at 2- and 10 weeks postoperatively. The smartphone application was used to evaluate change in gait dysfunction over time within the patients’ own environment using paired t test.

Results

The smartphone application demonstrated moderate-to-excellent intraclass correlation coefficients for reliability between-system (ICC range, 0.56–0.99), -limb (ICC range, 0.62–0.99) and -device (ICC range, 0.61–0.96) for gait analysis of healthy adults. Pearson correlations were low-to-very high between methods (r range, 0.45–0.99). Bland–Altman analysis revealed relative underestimation of spatiotemporal variables by the smartphone application compared to the motion system. For patients following total hip or knee arthroplasty, gait analysis using the OneStep application demonstrated significant improvement (p < 0.001, Cohen’s d > 0.95) in gait dysfunction between 2- and 10 weeks postoperatively.

Conclusion

The smartphone application can be a valid, reliable and feasible alternative to motion laboratories in evaluating deficits in gait dysfunction in various environments and clinical settings.

The Time Course of Quadriceps Strength Recovery After Total Knee Arthroplasty Is Influenced by Body Mass Index, Sex, and Age of Patients: Systematic Review and Meta-Analysis

Introduction

For patients with osteoarthritis who have undergone total knee arthroplasty (TKA), quadriceps strength is a major determinant of general physical function regardless of the parameters adopted for functional assessment. Understanding the time course of quadriceps strength recovery and effectiveness of different rehabilitation protocols is a must. Therefore, the aim of this study was to: (i) determine the magnitude of maximal voluntary strength (MVS) loss and the time course of recovery of the quadriceps muscle following TKA, (ii) identify potential moderators of strength outcomes, and (iii) investigate whether different rehabilitation practices can moderate the strength outcomes following TKA, respectively.

Design

General scientific databases and relevant journals in the field of orthopedics were searched, identifying prospective studies that investigated quadriceps’ MVS pre-to post-surgery.

Results

Seventeen studies with a total of 832 patients (39% males) were included. Results showed that in the early post-operative days, the involved quadriceps’ MVS markedly declined, after which it slowly recovered over time in a linear fashion. Thus, the greatest decline of the MVS was observed 3 days after TKA. When compared to pre-operative values, the MVS was still significantly lower 3 months after TKA and did not fully recover up to 6 months following TKA. Furthermore, a meta-regression analysis identified that the variables, time point of evaluation, patient age, sex, and BMI, significantly moderate the MVS of the quadriceps muscle.

Conclusion

The analyzed literature data showed that the decrease in strength of the involved quadriceps muscles following TKA is considerable and lasts for several months post-surgery. Therefore, we recommend to specifically target the strengthening of knee extensor muscles, preserve motor control, and apply appropriate nutrition to ensure a holistic quadriceps muscle recovery. Since age, sex, and BMI were found to be moderating factors in patients’ recovery, further research should include specific analyses considering these moderators.

The effects of preoperative neuromuscular electrical stimulation on the postoperative quadriceps muscle strength and functional status in patients with fast-track total knee arthroplasty

This study aimed to investigate the effect of pre- operative neuromuscular electrical stimulation (NMES) on postoperative quadriceps muscle strength, functional status, and quality of life in patients with fast-track total knee arthroplasty (TKA). This prospective study was carried out at Orthopedics department from September 2017 to October 2018. A total of 40 patients were randomly divided into NMES (n=20) and control group (n=20). Patients in NMES group were asked to use home NMES device daily for 20 minutes, 5 times a day, for 6 weeks before surgery. The control group was placed on the 6-week waiting list for surgery without any preoperative intervention. Standard home exercise program was applied to both groups after discharge. The patients were evaluated baseline, preoperatively (6-weeks after baseline) and at the 4th and 12th weeks after surgery. Knee range of motion, quadriceps muscle strength, patient-reported (WOMAC and KOOS) and performance-based activity limitation (30-second chair-stand test, 40-meter fast-paced walk test, and stair-climb test) were evaluated at each visit. Preoperative NMES resulted in significant improvement in KOOS-function in daily living and WOMAC total score (p≤0.05) but had a non-significant trend toward to improve quadriceps muscle strength, KOOS-pain and -other symptoms, performance- based activity limitation, and quality of life scores (p>0.05). However, there was no significant difference between groups in the postoperative period (p>0.05). NMES has beneficial effects in terms of patient- reported and performance-based physical functions and quality of life in preoperative period ; however, it does not provide any additional benefit for post- operative outcomes in patients with fast-track TKA.

Blood Flow Restriction Training Can Improve Peak Torque Strength in Chronic Atrophic Postoperative Quadriceps and Hamstrings Muscles

PURPOSE

To report a prospective study of patients who underwent blood flow restriction training (BFRT) for marked quadriceps or hamstring muscle deficits after failure to respond to traditional rehabilitation after knee surgery.

METHODS

The BFRT protocol consisted of 4 low resistance exercises (30% of 1 repetition maximum): leg press, knee extension, mini-squats, and hamstring curls with 60% to 80% limb arterial occlusion pressure. Knee peak isometric muscle torque (60° flexion) was measured on an isokinetic dynamometer.

RESULTS

Twenty-seven patients (18 females, 9 males; mean age, 40.1 years) with severe quadriceps and/or hamstrings deficits were enrolled from April 2017 to January 2020. They had undergone a mean of 5.3 ± 3.5 months of outpatient therapy and 22 ± 10 supervised therapy visits and did not respond to traditional rehabilitation. Prior surgery included anterior cruciate ligament reconstruction, partial or total knee replacements, meniscus repairs, and others. All patients completed 9 BFRT sessions, and 14 patients completed 18 sessions. The mean quadriceps and hamstrings torque deficits before BFRT were 43% ± 16% and 38% ± 14%, respectively. After 9 BFRT sessions, statistically significant improvements were found in muscle peak torque deficits for the quadriceps (P = .003) and hamstring (P = .02), with continued improvements after 18 sessions (P = .004 and P = .002, respectively). After 18 BFRT sessions, the peak quadriceps and hamstring peak torques increased > 20% in 86% and 76% of the patients, respectively. The failure rate of achieving this improvement in peak quadriceps and hamstring torque after 18 BFRT sessions was 14% and 24%, respectively.

CONCLUSIONS

BFRT produced statistically significant improvements in peak quadriceps and hamstring torque measurements after 9 and 18 sessions in a majority of patients with severe quadriceps and hamstring strength deficits that had failed to respond to many months of standard and monitored postoperative rehabilitation.

LEVEL OF EVIDENCE

Level IV therapeutic case series.

Blood flow restriction exercise to attenuate postoperative loss of function after total knee replacement: a randomized pilot study

Aging well is directly associated with a healthy lifestyle. The focus of this paper is to relate that attenuation of postoperative loss of muscle function after a total knee arthroplasty (TKA) is an important consideration. Because patients usually do not tolerate standard high-resistance exercise in the preoperative or postoperative period, they often experience a decline in strength and function. Therefore, we tested the feasibility and acceptability of an alternative low-resistance exercise protocol with blood flow restriction (BFR) using a tourniquet in the preoperative period for patients awaiting TKA. We recruited patients undergoing a TKA and randomized six to the BFR exercise for 4 weeks prior to surgery and four to standard of care (no exercise). We measured physical function using the Short Physical Performance Battery (SPPB), the 6-Minute Walk Test (6MWT), leg strength (peak torque), and pain (numerical pain score) 4 to 5 weeks preoperatively and 2 weeks postoperatively. The clinical management, e.g., anesthetic management, did not differ between groups. No complications were observed. Our findings demonstrate the feasibility and acceptability of the BFR intervention. Although preliminary and not powered for comparison, the BFR group demonstrated less decline in SPPB following surgery (−2.2, 95%CI:−4.4,0.1) compared to the no exercise group (−4.8, 95%CI:−7.8,−1.7). No differences were noted for the 6MWT, leg strength, and pain measurements. We conclude that preoperative low-resistance exercise using the BFR is feasible and acceptable, and this test warrants investigation as an intervention to potentially attenuate the postoperative loss of physical function after TKA.

Early postoperative straight leg raise is associated with shorter length of stay after unilateral total knee arthroplasty

PURPOSE

Shorter length of stay (LOS) after total knee arthroplasty (TKA) is cost-effective. Straight leg raise (SLR) is a common exercise prescribed after TKA, but the significance of early postoperative SLR is unknown. The primary aim of this study is to evaluate the association between early postoperative SLR and LOS. Secondary aims are to explore associations among early postoperative SLR, time to ambulation, and time to stairs climbing and identify factors related to postoperative SLR.

METHODS

888 TKAs (888 knees, 865 patients) performed at a tertiary hospital in 2016 were included for this retrospective study. All TKAs were performed with medial parapatellar approach and tourniquet. Time to events (SLR, ambulation, stair climbing), LOS and factors influencing these events were analysed using a multivariate Poisson regression model and logistic regression.

RESULTS

Patients who performed SLR on postoperative day 1 (POD1) had shorter LOS than those who did not (adjusted Mean Ratio (aMR) = 0.846, p < 0.001), with estimated mean LOS being 3.5 days and 4.1 days, respectively. Performing SLR on POD1 was also associated with shorter time to ambulation (aMR = 0.789; p < 0.001) and stair climbing (aMR = 0.811, p < 0.001). Female gender and higher rest pain on POD1 were associated with delayed postoperative SLR.

CONCLUSION

Performing SLR on POD1 after TKA is associated with shorter LOS, time to ambulation, and time to stair climbing. Early postoperative SLR can prognosticate early recovery and discharge. Optimization of preoperative muscle strength and postoperative pain may be important in early recovery after TKA.

Total Knee Arthroplasty Improved Locomotive Syndrome in Knee Osteoarthritis Patients: A Prospective Cohort Study Focused on Total Clinical Decision Limits Stage 3

Purpose

The purpose of this study is to investigate the treatment efficacy of total knee arthroplasty (TKA) on locomotive syndrome (LS) focusing on total clinical decision limit (CDL) stage 3 leading to revealing the motor function indicators that can predict LS improvement in knee osteoarthritis patients who had received TKA.

Methods

This prospective cohort study was conducted in 47 patients evaluated as total CDL stage 3 before TKA who received primary TKA on the operated side and were diagnosed with Kellgren-Lawrence grade 2, 3, or 4 knee osteoarthritis on the nonoperated side. LS was evaluated using stand-up test, two-step test, and 25-Question Geriatric Locomotive Function Scale. In addition, the motor function indicators which could predict the LS improvement were examined. All assessments were conducted before TKA and three months after TKA.

Results

Of the 47 subjects who were evaluated to be in total CDL stage 3 before TKA, 13 patients (27.7%) were determined to show improvements in total CDL. From the result of the decision tree analysis, when the CDL of the two-step test before TKA was 1 or less, the improvement rate was 83.3%. Even if the CDL of the two-step test before TKA was higher than 1 and if the 3 m-Timed Up and Go test (3m-TUG) before TKA was 9.6 or less, the improvement rate was 50%.

Conclusions

As of three months after surgery, TKA can improve LS in about 30% of knee osteoarthritis patients. A two-step test before TKA and 3m-TUG before TKA can be used as motor function indicators to predict LS improvement. This study provides useful information for setting the goal for rehabilitation prior to surgery.

Gait mechanics are influenced by quadriceps strength, age, and sex after total knee arthroplasty

Although most patients are satisfied with outcomes after total knee arthroplasty (TKA), many retain preoperative altered gait mechanics. Identifying patient characteristics associated with gait mechanics will improve rehabilitation strategies and enhance our understanding of movement disorders. Therefore, the purpose of this study was to identify which patient characteristics are related to gait mechanics in the surgical limb during walking post-TKA. Patient characteristics included age, body mass, sex, quadriceps strength, self-reported function, and knee pain. General linear regression was used to compare patient characteristics associated with gait mechanics, after controlling for gait speed, functional capacity and time from surgery. We tested 191 patients cross-sectionally at 6-24 months after primary, unilateral TKA. Quadriceps weakness in the surgical limb was associated with less peak vertical ground reaction force (PvGRF) (β = .245, p = .044), knee extension moment (β = .283, p = .049), and knee extension excursion (β = .298, p = .038). Older age (β = .168, p = .050) was associated with less PvGRF. Quadriceps strength in the nonsurgical limb (β = -.357, p = .021) was associated with greater knee extension excursion in the surgical limb. Females with TKA (β = -.276, p = .007) had less knee flexion excursion compared to males. Faster gait speed was also associated with greater PvGRF (β = .585, p < .001), knee extensor moment (β = .481, p < .001), and knee flexion excursion (β = .318, p < .001). Statement of Clinical Significance: This study showed quadriceps weakness, slower gait speed, older age and being female were related to altered gait mechanics post-TKA. These findings will help clinicians better educate patients and develop targeted interventions for improving care in patients post-TKA.

Association between Preoperative Long-Chain Polyunsaturated Fatty Acids and Oxidative Stress Immediately after Total Knee Arthroplasty: A Pilot Study

Quadriceps muscle atrophy following total knee arthroplasty (TKA) can be caused by tourniquet-induced ischemia–reperfusion (IR) injury, which is often accompanied by oxidative stress and inflammatory responses. n-3 long-chain polyunsaturated fatty acids (LCPUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), exert antioxidant and anti-inflammatory effects against IR injury, whereas n-6 LCPUFAs, particularly arachidonic acid (AA), exhibit pro-inflammatory effects and promote IR injury. This study aimed to examine whether preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio are associated with oxidative stress immediately after TKA. Fourteen eligible patients with knee osteoarthritis scheduled for unilateral TKA participated in this study. The levels of serum EPA, DHA, and AA were measured immediately before surgery. Derivatives of reactive oxygen metabolites (d-ROMs) were used as biomarkers for oxidative stress. The preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio were found to be significantly negatively correlated with the serum d-ROM levels at 96 h after surgery, and the rate of increase in serum d-ROM levels between baseline and 96 h postoperatively. This study suggested the preoperative serum EPA + DHA levels and the (EPA + DHA)/AA ratio can be negatively associated with oxidative stress immediately after TKA.

Aquatic Exercise and Land Exercise Treatments after Total Knee Replacement Arthroplasty in Elderly Women: A Comparative Study

Background and Objectives: Early intensive exercise after total knee replacement arthroplasty (TKRA) has become increasingly popular due to its ability to enhance knee physical function and reduce pain. When implemented exclusively, aquatic exercise (AE) appears to be more advantageous than land exercise (LE), particularly in the early phase after TKRA. Our study aimed to compare the clinical efficacy of AE and LE with respect to their effects on pain and physical function after TKRA. Materials and Methods: Between February 2008 and January 2020, 100 female patients who underwent TKRA were enrolled in this retrospective study. We measured the range of motion (ROM) of the knee, the isokinetic strength of the knee joint (function), and pain both initially and one month after TKRA. Two weeks after TKRA, the participants were enrolled in either the AE or the LE program for a total of two weeks. Two 30 min sessions of intensive ROM and knee strengthening exercises and balance training were provided to the AE and LE groups for 10 days. The home exercise group (HE) only received information on ROM and strengthening exercises. There were 33, 21, and 46 patients allocated to the AE, LE, and HE groups, respectively. Results: The ROM of the side on which surgery was performed improved significantly in all groups, as did the pain scores. In the AE group, the knee flexor strength showed a tendency toward improvement. Contrastingly, there was no significant improvement in the knee extensor strength in the AE group. Conclusions: Overall, the AE and LE groups showed superior outcomes compared with HE. In addition, the AE group demonstrated some improvement in knee muscle strength even with a short hospital stay. Further study with long-term follow-up should be performed to better define the outcomes.

Longitudinal study of knee load avoidant movement behavior after total knee arthroplasty with recommendations for future retraining interventions

BACKGROUND

This study aimed to evaluate clinical and biomechanical changes in self-report survey, quadriceps strength and gait analysis over 3- and 6-months post-total knee arthroplasty (TKA) and confirm the immediate effects of two forms of kinetic biofeedback on improving inter-limb biomechanics during a physically demanding decline walking task.

METHODS

Thirty patients with unilateral TKA underwent testing at 3- and 6-months following surgery. All underwent self-report survey, quadriceps strength and gait analysis testing. Patients were assigned to one of two types of biofeedback [vertical ground reaction force (vGRF), knee extensor moment (KEM)].

RESULTS

No decrease in gait asymmetry was observed in non-biofeedback trials over time (p > 0.05), despite significant improvements in self-report physical function (p < 0.01, Cohen d = 0.44), pain interference (p = 0.01, Cohen d = 0.68), numeric knee pain (p = 0.01, Cohen d = 0.74) and quadriceps strength (p = 0.01, Cohen d = 0.49) outcomes. KEM biofeedback induced significant decrease in total support moment (p = 0.05, Cohen f² = 0.14) and knee extensor moment (p = 0.05, Cohen f² = 0.21) asymmetry compared to using vGRF biofeedback at 6-months. vGRF biofeedback demonstrated significant decrease in hip flexion kinematic asymmetry compared to KEM biofeedback (p = 0.05, Cohen f² = 0.18) at 6-months.

CONCLUSION

Gait compensation remained similar from 3- to 6-months during a task requiring greater knee demand compared to overground walking post-TKA, despite improvements in self-report survey and quadriceps strength. Single session gait symmetry training at 6-month supports findings at 3-month testing that motor learning is possible. KEM biofeedback is more effective at immediately improving joint kinetic loading compared to vGRF biofeedback post-TKA.

Assessing the feasibility of using the short physical performance battery to measure function in the immediate postoperative period after total knee replacement

Measurements of physical function after total knee arthroplasty (TKA) are uncertain and require investments for special equipment, space, and staff. Therefore, we evaluated the Short Physical Performance Battery (SPPB) 4 to 6 weeks preoperatively and 2 weeks following TKA as this test battery addresses lower extremity strength, coordination, and balance, without additional special investments. For context, we also employed the Six-Minute Walk test (6MWT) and peak torque knee extension. Our analysis consisted of three women and one man, with average ages of 68.3±3.9 years. Patients showed a decrease in all functional measurements: SPPB (mean change: -4.8±1.9, 44% decrease), 6MWT (-0.37±.21 m/s, 34% decrease), and peak torque (-11.8±8.8°/s, 68% decrease). Our findings suggest the SPPB is feasible and can be integrated easily in daily clinical practice.

Quadriceps muscle group function and after total knee arthroplasty-asystematic narrative update

BACKGROUND

This article systematically summarizes the present evidences, published in the last 20 years, regarding the pre- and post-operative factors, which may influence recovery of the function of the quadriceps muscle group following total knee arthroplasty (TKA). We following the PRISMA methodology, including meta-analyses and high-level evidence studies (prospective trials, and, when unavailable, retrospective studies).

SOURCES OF DATA

Pubmed and Cochrane databases: 582 articles were identified and 54 of them were selected.

AREAS OF AGREEMENT

Tourniquets inflated at high pressure exert a detrimental effect on the quadriceps muscle group. Faster quadriceps recovery takes place using mini-invasive approaches, an eight-week rehabilitation period including balance training and the use of nutraceuticals.

AREAS OF DISAGREEMENT

Pre-habilitation and pre-operative factors, analgesic methods and different TKA implants.

GROWING POINTS AND AREAS TIMELY FOR DEVELOPING RESEARCH

Telerehabilitation seems a cost-effective tool for rehabilitation after TKA. Patients' optimization protocols before TKA should include standardized nutraceuticals intake.

The condition of the contralateral knee may induce different degrees of knee extensor strength asymmetry and affect functionality in individuals with unilateral or bilateral osteoarthritis

BACKGROUND

Loss of knee extensor strength in individuals with knee osteoarthritis (KOA) may induce inter-limb strength asymmetries and alter functionality. The aims were to analyse whether the condition of the uninvolved knee (advanced to severe KOA or no affection) may induce different degrees of knee extensor strength asymmetry in individuals with KOA and to study whether functionality may differ in cases of unilateral or bilateral KOA.

METHODS

Sixty-eight subjects with advance-to-severe KOA were categorized into two groups (unilateral or bilateral KOA). The knee extensor strength ratio (KESR), and self-reported and performance-based functionality were analysed and compared. Sex and age were independent factors. One- and two-way analysis of variance assessed for significant between-group differences (95% confidence interval (CI)).

RESULTS

Participants with unilateral KOA presented with 20% knee extensor strength asymmetry. The mean difference with the bilateral KOA group in terms of Knee Extensors Strength Ratio was 0.2 (95% CI 0-0.3; P = 0.021), of the Oxford Knee Scale score was 4.2 (95% CI 3.4-5.1; P = 0.037), and of the Timed Up and Go was 1.3 s (95% CI 0.5-2.2; P > 0.05). There were significant sex and age interactions (P < 0.05).

CONCLUSIONS

Individuals with unilateral or bilateral KOA present with different degrees of knee extensor strength asymmetry. The non-affected knee seems to help to better develop functional tasks in cases of unilateral condition. The findings may help the design of tailored strengthening interventions in which each knee condition in individuals with KOA should be considered.

Effects of preoperative low-intensity training with slow movement on early quadriceps weakness after total knee arthroplasty in patients with knee osteoarthritis: a retrospective propensity score-matched study

Background

Severe and early quadriceps weakness (QW) after total knee arthroplasty (TKA), which is caused by acute inflammation resulting from surgical trauma and tourniquet-induced ischemia-reperfusion (IR) injury, can be especially problematic. We focused on tourniquet-induced IR injury, because it has been shown to be preventable through ischemic and exercise preconditioning. Low-intensity resistance exercise with slow movement and tonic force generation (LST) share some similarities with ischemic and exercise preconditioning. The present study primarily aimed to clarify the efficacy of preoperative LST program as prehabilitation for early QW among patients with TKA using propensity score matching analysis.

Methods

This single-center retrospective observational study used data from patients with knee osteoarthritis (n = 277) who were scheduled to undergo unilateral TKA between August 2015 and January 2017. Those with missing outcome data due to their inability to perform tests were excluded. The LST group included participants who performed LST and aerobic exercise (LST session) more than seven times for three months prior to surgery. The control group included participants who performed less than eight LST sessions, a general and light exercise or had no exercise for three months prior to surgery. Knee circumference, thigh volume, knee pain during quadriceps strength test (QST) and timed up and go test (TUG), quadriceps strength, and TUG were measured before and 4 days after surgery. Knee swelling, thigh swelling, Δknee pain, QW, and ΔTUG were determined by comparing pre- and postoperative measurements.

Results

Propensity score matching generated 41 matched pairs who had nearly balanced characteristics. The LST group had a significantly lower knee and thigh swelling, QW, and ΔTUG compared to the control group (all, p < 0.05). No significant differences in Δknee pain during the QST and TUG were observed between both groups (both, p > 0.05).

Conclusions

The present study demonstrated the beneficial effects of preoperative LST program on knee swelling, thigh swelling, QW, and walking disability immediately after TKA.

Effect of Nonelastic Compression With an Adjustable Wrap After Total Knee Arthroplasty

Swelling is a common phenomenon after total knee arthroplasty, with potential for negative impact on the rehabilitation process and final outcome. The aim of this study was to investigate the effectiveness of a new compression protocol with a self-adjustable, nonelastic compression wrap for the knee region. This study was conducted as a prospective comparative study. Total leg volume and the circumference of the knee at three levels were compared between groups. The results of our study suggest that the application of the new compression protocol has no effect on swelling in the acute postoperative phase (0-2 days) but reduces swelling at Day 14 within the subacute phase. The observed positive effect of the compression protocol could be of clinical importance in the subacute phase as well as for a subgroup of patients suffering from aberrant quadriceps weakness concomitant with knee swelling.

Effects of Muscle Strengthening around the Hip on Pain, Physical Function, and Gait in Elderly Patients with Total Knee Arthroplasty: A Randomized Controlled Trial

Background: Functional limitations may still remain even after a patient completes a traditional quadriceps-based rehabilitative program after total knee arthroplasty. Based on studies reporting that patients with knee osteoarthritis have muscle weakness around the hip joint after total knee arthroplasty, we investigated whether strengthening the hip muscles can reduce pain and improve the physical function and gait of patients who underwent total knee arthroplasty. Methods: Patients were randomly divided into three groups: hip, quadriceps, and control. The hip group (n = 19) completed an extensor, adductor, and external muscle strengthening exercise program. The quadriceps group (n = 20) completed a quadriceps strengthening exercise program. The control group (n = 16) completed an active range of motion exercises. Therapy was conducted thrice weekly for 12 weeks. Pain and function items from the Western Ontario and McMaster Universities Osteoarthritis Index, Alternate Step Test, Five Times Sit to Stand Test, and Single Leg Stance Test were performed to assess pain and physical function. In the gait analysis, stride, single-stance (%), double-stance (%), and gait speed were measured. Data were collected at baseline and at 4, 8, and 12 weeks after the intervention. Results: The hip group showed more significant improvements in pain and performance on the Alternate Step Test and Single Leg Stance Test than the quadriceps and control groups. In the gait analysis, the hip group showed the largest improvements in single stance and double stance. Conclusions: In conclusion, a 12-week hip muscle strengthening exercise program effectively improves the physical function and gait of patients who have undergone total knee arthroplasty.

Feasibility of supplemental robot-assisted knee flexion exercise following total knee arthroplasty

BACKGROUND

The Hybrid Assistive Limb (HAL) is a robotic exoskeleton designed to support impaired limbs.

OBJECTIVE

We aimed to evaluate whether active exercise using a single-joint HAL (HAL-SJ) following total knee arthroplasty can facilitate the recovery of knee flexion.

METHODS

Twenty-two patients who underwent total knee arthroplasty were randomly allocated to the HAL-SJ group (n= 12) or conventional physical therapy (CPT) group (n= 10). On postoperative day 5, patients performed active knee flexion exercises either with or without HAL-SJ assistance every second day. Outcome measures included active and passive knee flexion range of motion (ROM), muscle strength, and pain intensity, as assessed by the visual analog scale, and were assessed on postoperative days 5 (pre-treatment) and 10 (post-treatment). Active ROM was measured at 6 months postoperatively; further long-term follow-up was performed by telephone interview.

RESULTS

Both groups showed significant improvement between postoperative days 5 and 10 in all outcome measures. Improvements in active ROM (p< 0.01), passive ROM (p< 0.01), muscle strength (p< 0.01), and pain (p< 0.01) were significantly greater in the HAL-SJ group than in the CPT group. Long-term outcomes were also significantly better in the HAL-SJ group.

CONCLUSIONS

HAL therapy enables patients to perform painless active movements and facilitates the recovery of knee function.

Home-based motor imagery intervention improves functional performance following total knee arthroplasty in the short term: a randomized controlled trial

BACKGROUND

Motor imagery (MI) is effective in improving motor performance in the healthy asymptomatic adult population. However, its possible effects among older orthopaedic patients are still poorly investigated. Therefore, this study explored whether the addition of motor imagery to routine physical therapy reduces the deterioration of quadriceps muscle strength and voluntary activation (VA) as well as other variables related to motor performance in patients after total knee arthroplasty (TKA).

METHODS

Twenty-six patients scheduled for TKA were randomized to either MI practice combined with routine physical therapy group (MIp) or to a control group receiving physical therapy alone (CON). MIp consisted of maximal voluntary isometric contraction (MViC) task: 15 min/day in the hospital, then 5 times/week in their homes for 4 weeks. MViC and VA of quadriceps muscle, knee flexion and extension range of motion, pain level, along with a Timed Up-and-Go Test (TUG) and self-reported measure of physical function (assessed using the Oxford Knee Score questionnaire [OKS]) were evaluated before (PRE) and 1 month after surgery (POST).

RESULTS

Significantly better rehabilitation outcomes were evident on the operated leg for the MIp group compared to CON: at POST, the MIp showed lower strength decrease (p = 0.012, η2 = 0.237) and unaltered VA, significantly greater than CON (p = 0.014, η2 = 0.227). There were no significant differences in knee flexion and extension range of motion and pain level (p > 0.05). Further, MIp patients performed better in TUG (p < 0.001, η2 = 0.471) and reported better OKS scores (p = 0.005, η2 = 0.280). The non-operated leg showed no significant differences in any outcomes at POST (all p > 0.05). In addition, multiple linear regression analysis showed that failure of voluntary activation explained 47% of the quadriceps muscle strength loss, with no significant difference in perceived level of pain.

CONCLUSION

MI practice, when added to physical therapy, improves both objective and subjective measures of patients' physical function after TKA, and facilitates transfer of MI strength task on functional mobility.

TRIAL REGISTRATION

Retrospectively registered on ClinicalTrials.gov NCT03684148.

Associations between gait analysis parameters and patient satisfaction one year following primary total knee arthroplasty

BACKGROUND

The purpose of this prospective study was to understand the relation between gait outcomes and patient satisfaction one year after total knee arthroplasty (TKA).

METHODS

Seventy-nine patients were evaluated before and one year after TKA using clinical gait analysis. Specific gait outcomes were analyzed: gait speed, stance phase, range of motion (ROM) knee flexion and maximal knee flexion. The parameters of interest selected for the statistical analysis were: gait speed and maximal knee flexion during gait. The Western Ontario and MacMaster Osteoarthritis Index (WOMAC) and patient satisfaction were also assessed. The satisfaction was evaluated using a questionnaire and was splited in five categories: very unsatisfied, unsatisfied, neutral, satisfied or very satisfied. To assess associations between patient satisfaction and maximal knee flexion during gait and gait speed, an unadjusted ordinal logistic regression analysis was used. The analysis was then adjusted for covariates: age and Body Mass Index (BMI) before surgery and WOMAC pain one year after surgery.

RESULTS

All gait outcomes after TKA had significantly improved. The ordinal logistic regression analysis found significant associations between patient satisfaction and maximal knee flexion after TKA (unadjusted and adjusted) but not for gait speed.

CONCLUSION

These findings show that all patients improved their gait outcomes one year after TKA but only a higher maximal knee flexion during gait may influence the level of patient satisfaction.

Step descent strategy is altered bilaterally despite unilateral muscle strength impairment after total knee arthroplasty

PURPOSE

Muscle weakness and difficulty descending stairs are common after unilateral total knee arthroplasty (TKA), but the relationship between each is unclear. The purpose of this study was to compare lower extremity muscle strength, lower extremity support moments during step descent, and assess relationships between each.

METHODS

The study included 40 subjects (20 post-TKA, 20 control). Knee extensor, hip abductor, and hip external rotator strength were measured and biomechanical analyses of step descent performed. Patients with TKA were assessed 3 and 6 months post-surgery.

RESULTS

At 3 and 6 months post-TKA, operated limb hip external rotator and knee extensor strength were impaired compared to the non-operated limb (p < 0.01); however, no between-limb differences were observed during step descent. Compared to the control group, hip external rotator and knee extensor strength, total lower extremity support moment, and knee support moment during step descent were impaired post-TKA (p < 0.05). At 6 months post-TKA, knee extensor and hip external rotator strength correlated with total support moment during step descent (r_s = 0.40, 0.41, p < 0.02). Hip abductor and external rotator strength negatively correlated with knee support moment during step descent (r_s = - 0.35, - 0.39, p < 0.03).

CONCLUSIONS

Persistent operative limb knee extensor and hip external rotator muscle weakness are noted following unilateral TKA. Despite unilateral weakness, bilateral alterations in step descent strategy occur following TKA. Patients with TKA utilize hip musculature to reduce knee muscle demand during step descent, possibly contributing to limitations in long-term step descent performance.

Reliability, responsiveness, and validity of handheld dynamometry for assessing quadriceps strength in total knee arthroplasty

PURPOSE

To determine the reliability, responsiveness, validity, and agreement of handheld dynamometry, relative to electromechanical dynamometry, for assessing quadriceps strength surrounding total knee arthroplasty.

METHODS

Fifty-six patients (48% female) undergoing total knee arthroplasty were assessed prior to surgery and at 2 and 6 weeks following surgery. Maximum isometric quadriceps force was assessed at each time point by handheld dynamometry and electromechanical dynamometry. Within-session test-retest reliability was determined by intraclass correlation coefficient (ICC). Standard error of measurement and relative standard error (RSE) values were calculated. Standardized response means were used to describe responsiveness. Pearson's correlations examined construct validity. Agreement was assessed by the Bland-Altman method.

RESULTS

Both handheld dynamometry and electromechanical dynamometry demonstrated excellent test-retest reliability (ICC >0.90) and RSE (<15%). Both methods were responsive, with large postoperative standardized response means of 1.57 (handheld dynamometry) and 1.37 (electromechanical dynamometry). Pearson's correlations were moderate to strong. The Bland-Altman analysis revealed underestimation of force by handheld dynamometry, although this effect was diminished in the early postoperative period.

CONCLUSIONS

Our results suggest handheld dynamometry is a promising tool for monitoring quadriceps strength in patients pre- and post-total knee arthroplasty.IMPLICATIONS FOR REHABILITATIONThis study provides evidence of high reliability and responsiveness of handheld dynamometry for assessing quadriceps strength throughout a clinically relevant time frame for patients with total knee arthroplasty.There is construct validity of handheld dynamometry for measuring quadriceps strength, with moderate to high correlations between handheld dynamometry and electromechanical dynamometry, both pre- and post-total knee arthroplasty.Rehabilitation professionals should be aware that handheld dynamometry and electromechanical dynamometry do not agree in terms of the force measurement itself; particularly at higher force values, handheld dynamometry underestimates force output relative to electromechanical dynamometry.Overall, this study supports the use of handheld dynamometry for monitoring quadriceps strength in clinical settings for patient with total knee arthroplasty.

Results of muscle strength and range of motion after total open knee synovectomy

AIM OF THE STUDY

Scar tissue formation after synovectomy limits range of motion and causes muscle atrophy. The functional results for patients who underwent total open knee synovectomy often included questionnaires, and assessment of muscle strength was lacking in the literature. Therefore, we aimed to identify the strength and range of motion outcomes for patients who underwent total open synovectomy and to compare the results with the contralateral limb and healthy individuals.

METHOD

Knee range of motion and muscle strength were assessed in fourteen patients that underwent total (anterior and posterior) open knee synovectomy and were compared with the contralateral limb and with 14 healthy individuals matched by sex, age, height, and weight.

RESULTS

The range of motion of flexion decreased 8.4% compared with the contralateral limb (95% CI - 18.9 to - 4.7, p = 0.002) and 9.9% compared with the control group (95% CI 3.9-14.9, p < 0.01). Knee extension strength decreased by 35% compared with the contralateral limb (95% CI 11.1-77.2, p = 0.01) and 37% compared with the control group (95% CI - 112.4-12.1, p = 0.01).

CONCLUSION

Despite the aggressiveness of the surgical procedure, the patients achieved satisfactory functional results.

Neurostructural correlates of strength decrease following total knee arthroplasty: A systematic review of the literature with meta-analysis

Recent literature suggests that alterations in both neural and structural components of the neuromuscular system are major determinants of knee extensor muscle weakness after total knee arthroplasty (TKA). Therefore, the goal of this study was to investigate the maximal voluntary strength (MVS), voluntary muscle activation (VMA), and the cross-sectional area (CSA) of the muscle, up to 33 months after the TKA.  We searched relevant scientific databases and literature for outcomes of interest, including quadriceps MVS, VMA, and CSA. Ten studies met the inclusion criteria and involved a total of 289 patients. The quality of the studies was evaluated by Methodological Index for Non-Randomized Studies (MINORS). Results showed that quadriceps MVS markedly declines in the early postoperative period, after which it slowly and linearly recovers over time. However, the same phenomenon was not observed for VMA and CSA, which were not significantly altered after the TKA. Furthermore, a meta-regression analysis revealed that the change in VMA accounted for 39% of the relative change in quadriceps strength (R2=0.39; p=0.015) in the early postoperative period. Patients treated with TKA had considerable weakness of the quadriceps muscle, which was detectable up to 3 months after surgery. Although the change in VMA largely explains quadriceps weakness, this change and CSA differences were not significant, suggesting that other neural correlates, such as hamstrings coactivation, might alter quadriceps muscle function. Thus, more attention should be paid to address VMA failure and coactivation of antagonist muscles.  More comprehensive rehabilitation approaches may be required to target the whole neural circuit controlling the motor action.

Combined Application of Electrically Stimulated Antagonist Muscle Contraction and Volitional Muscle Contraction Prevents Muscle Strength Weakness and Promotes Physical Function Recovery After Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND

Osteoarthritis of the knee (KOA) is the most common cause of disability in both the United States and in Japan. The Hybrid training system (HTS) has been developed as a resistance exercise method combining electrical stimulation with voluntary exercise. The purpose of the present study is to compare the effects of a conventional rehabilitation program with or without HTS on knee muscle strength and physical function after Total knee arthroplasty (TKA).

METHODS

We conducted a 12-week randomized controlled trial, using standard rehabilitation (the control group, n = 27) or standard rehabilitation plus HTS (the HTS group, n= 26), in 53 female patients after TKA. The HTS group underwent HTS three times per week for twelve weeks after TKA. Muscle strength, thigh circumference, physical functional testing, QOL and knee pain were assessed before surgery, 6 and 12 weeks after TKA.

RESULTS

There was a significant decrease in quadriceps strength and thigh circumference on the operative side in the control group, but not in the HTS group at 6 weeks. Hamstring strength on the operative side in the HTS group significantly increased and thigh circumference was bigger than in the control group at 12 weeks. Physical function improved at 6 weeks in the HTS group, but not in the control group. Knee pain significantly improved in both groups at 6 weeks.

CONCLUSIONS

HTS was effective in preventing quadriceps weakness and in improving physical function and QOL after TKA.

Intensive, personalized multimodal rehabilitation in patients with primary or revision total knee arthroplasty: a retrospective cohort study

Background

Recent evidence has shown that many patients suffer from persistent pain and impaired function after primary or revision total knee arthroplasty (TKA). Post-surgical complications may in addition decrease physical performances and lead to more pain and impacted quality of life.

The purpose of the study was to assess the changes in pain intensity and functional capacity among patients with post-surgical complications after TKA three weeks of intensive, personalized multimodal rehabilitation.

Methods

A retrospective cohort study consisting of 217 patient of which 166 had primary TKA and 51 had revision TKA was conducted. On average, primary TKA patients and revision TKA patients were 3.7 and 2.7 months post-surgical, respectively. All patients have had post-surgical complications and were referred to an inpatient rehabilitation department, where they received a personalized three-week intensive, multimodal rehabilitation protocol. The rehabilitation consisted of sessions targeting neuromuscular function, postural control, and flexibility, sessions focusing on improving muscle strength and cardiovascular function and sessions with focus on gait retraining. The frequency of training was 2–4 sessions/day. The primary outcome was the Knee injury and Osteoarthritis Outcome Score (KOOS) and secondary outcomes were pain intensities measured using numerical rating scale, 6 min. walking test, stair-climbing test and range of motion for knee flexion and extension. Outcome measures were assessed at baseline upon referral and at follow-up before discharge.

Results

All outcomes, except pain at rest in the revision group, improved significantly. KOOS subscales, improved 8.5 to 14.2 in the primary TKA group (p < 0.001) and 6.9 to 10.8 in the revision group (p < 0.001). For the TKA group, effect sizes were medium-to-large for all KOOS subscales, 6 min. walking test, stair-climbing test, and pain intensity during activity. For the revision group, effect sizes were medium-to-large for KOOS subscales symptoms and activity of daily living, 6 min. walking test, stair-climbing test, and knee flexion.

Conclusion

Patients with post-surgical complications after primary or revision TKA experienced clinical relevant improvement in self-reported outcomes, pain relief, and improved physical performances after three weeks of personalized multimodal rehabilitation. The results suggest that an intensive, multimodal approach might be useful to obtain clinically relevant improvements.

Specific and general adaptations following motor imagery practice focused on muscle strength in total knee arthroplasty rehabilitation: A randomized controlled trial

BACKGROUND

Motor imagery (MI) has been a widely used strategy in the past two decades to enhance physical capabilities among orthopaedic patients. However, its effectiveness is still questioned, since the demonstrated effects were likely task-dependent, with little evidence of transfer to tasks not specifically trained with MI.

OBJECTIVE

The aim of this study was to investigate whether an MI practice focused on maximal isometric knee extension strength, causes additional specific and general adaptations upon neuromuscular and functional variables when compared to conventional rehabilitation only, in patients submitted to total knee arthroplasty (TKA).

DESIGN

Parallel group randomized controlled clinical trial.

PARTICIPANTS

Thirty-four patients (56% man) submitted to TKA.

PROGRAM

Patients were randomly assigned to an MI practice group (MIp: 15 minutes per day/5 days per week in addition to routine physical therapy) or control group (CON) that performed routine physical therapy alone for four weeks.

OUTCOME MEASURES

The maximal isometric knee extension strength of the operated leg was defined as the primary outcome. Secondary outcomes were spatial and temporal gait parameters, 30-second chair sit-to-stand performance, a self-reported physical function assessed by the Lower Extremity Functional Scale (LEFS) questionnaire, and an MI ability score. All measurements were conducted before and one month after TKA.

RESULTS

Significant differences in treatment effects were observed for the MIp group compared to CON: the MIp showed less strength decrease (ES = 1.15, 95% CI: 0.32, 1.99, p = 0.022); faster self-selected speed under single (ES = 2.12, 95% CI: 1.16, 3.08, p = 0.001) and dual task (ES = 1.59, large, 95% CI: 0.67, 2.50, p = 0.002) conditions; brisk-pace gait speed during single (ES = 1.32, 95% CI: 0.47, 2.17, p = 0.020) and dual task conditions (ES = 1.31, large, 95% CI: 0.38, 2.23, p = 0.013); improved chair sit-to-stand (ES = 1.45, large, 95% CI: 0.58, 2.31, p = 0.004) performance; and a higher score on MI ability questionnaires for kinaesthetic imagery (KI) (ES = 0.55, 95% CI: -0.23, 1.34, p = 0.010) and internal visual imagery (EVI) (ES = 0.99, 95% CI: 0.18, 1.80, p = 0.039) scales, respectively. In addition, only MIp showed unaltered single and double support periods, as well as stride length and cadence during single task self-selected gait condition. Finally, analysis showed that the improved MI ability score achieved at the end of MI training was significantly correlated with the changes in the strength of the operated leg (kinaesthetic imagery: r = 0.741, p = 0.004; and internal visual imagery: r = 0.623, p = 0.023).

CONCLUSIONS

MI training, when added in a corollary to routine physical therapy, led to improvements in both specific and general adaptations that were related to patients' physical capabilities. While future studies must also evaluate the long-term effects, conducting MI training during acute and post-acute rehabilitation phases is advised, especially when the extent and range of physical exercise is limited or made impossible.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03684148.

Light intensity physical activity increases and sedentary behavior decreases following total knee arthroplasty in patients with osteoarthritis

PURPOSE

To describe objectively measured changes in the volume and pattern of physical activity and sedentary behavior in patients undergoing total knee arthroplasty for osteoarthritis.

METHODS

Physical activity and sedentary behavior were measured in patients (13 males, 76 females) with a mean age of 64 years (range 55-80) and end-stage osteoarthritis of the knee, using an accelerometer (ActiGraph GT3X+) for seven consecutive days (24 h/day) prior to, 6 weeks and 6 months after total knee arthroplasty. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), University of California Los Angeles (UCLA) Activity index and range of motion (ROM) were also assessed.

RESULTS

Proportion of time spent in sedentary behavior decreased from baseline to 6 months (mean 70.1 vs. 64.0%; p = 0.009) and the interruptions to sedentary behavior improved between baseline and 6 months after total knee arthroplasty (mean 85.0-93.0 breaks/day, p = 0.014). Proportion of time spent in light physical activity increased from baseline to 6 months after total knee arthroplasty (29.0 vs. 34.8%; p = 0.008). There was no change in time spent in moderate to vigorous physical activity after total knee arthroplasty. WOMAC (median 71.0 vs. 4.0, p < 0.001), UCLA (median 2.0 vs. 5.0, p < 0.001) as well as ROM [median (0.0°-90.0°) vs. (0.0°-110°), p < 0.05] scores improved between baseline and 6 months after total knee arthroplasty.

CONCLUSION

Clinically, functional improvements in patients following total knee arthroplasty may be assessed by objectively measuring changes in low intensity activity behaviors. The use of accelerometers in this study gives new insights into activity accumulation patterns in a clinical population and highlights their use in determining a behavioral response to an intervention.

LEVEL OF EVIDENCE

II.

Incorporating hip abductor strengthening exercises into a rehabilitation program did not improve outcomes in people following total knee arthroplasty: a randomised trial

QUESTION

In adults following primary total knee arthroplasty, does the incorporation of hip abductor strengthening exercises into a 6-week rehabilitation program improve muscle strength, functional performance and patient-reported outcomes at the end of rehabilitation and at 26 weeks?

DESIGN

Randomised controlled trial with concealed allocation, blinded assessors and intention-to-treat analysis.

PARTICIPANTS

One hundred and five adults admitted to an inpatient rehabilitation facility immediately following total knee arthroplasty.

INTERVENTION

Participants in both groups attended 12 days of inpatient physiotherapy followed by 6 weeks of outpatient physiotherapy, which aimed to improve knee range of movement, strength and mobility. The experimental group completed a standard rehabilitation protocol with the addition of hip abductor strengthening. The control group completed the same standard rehabilitation protocol, with the addition of 15 minutes of general functional exercises.

OUTCOME MEASURES

Primary outcomes were the Knee Injury and Osteoarthritis Outcome Score (KOOS) and isometric hip abductor muscle strength normalised to body mass index. Secondary outcome measures included the stair climb test, 6-minute walk test, Timed Up and Go test, 40-m fast-paced walk test, 30-second chair stand test, step test, isometric quadriceps muscle strength, Lower Extremity Functional Scale, and Short Form-12.

RESULTS

The experimental intervention did not result in significantly greater improvements in hip strength, KOOS or any of the secondary outcome measures than the control intervention at 6 weeks or 26 weeks.

CONCLUSION

Similar improvements in muscle strength, functional performance and patient-reported outcomes were observed whether specific hip-strengthening exercises were incorporated or general functional exercises were continued instead as part of a postoperative rehabilitation program for participants after total knee arthroplasty.

REGISTRATION

ANZCTR 12615000863538.

Rate of torque development is the primary contributor to quadriceps avoidance gait following total knee arthroplasty

BACKGROUND

Following rehabilitation for total knee arthroplasty, "quadriceps avoidance gait", defined by limited knee flexion angle excursion during walking, persists and contributes to poor long-term outcomes. Given the presence of several post-surgical impairments, identifying the contribution of multiple factors to knee flexion angle excursion is important to developing targeted interventions to improve recovery after total knee arthroplasty.

RESEARCH QUESTIONS

Which outcomes continue to improve following rehabilitation for total knee arthroplasty? What are the primary contributors to impaired knee flexion angle excursion during walking following total knee arthroplasty?

METHODS

Peak muscle strength and rate of torque development of the quadriceps, hip abductors, and hip external rotators, five-time sit-to-stand test, Knee Injury & Osteoarthritis Outcome Score, and gait mechanics were assessed in 24 participants at three and six months post-surgery. Paired sample t-tests or Wilcoxon Signed-Rank tests were used to compare outcomes between assessments. Stepwise multiple linear regression were used to assess the contribution of each measure to knee flexion angle excursion.

RESULTS

Significant improvements were noted in all outcomes except hip external rotation rate of torque development, gait speed, and knee flexion angle excursion. Quadriceps rate of torque development and knee pain significantly contributed to knee flexion angle excursion at three months (Adjusted R² = 0.342), while quadriceps rate of torque development and peak hip external rotation strength significantly contributed at six months (Adjusted R² = 0.436).

SIGNIFICANCE

While higher pain levels at three months and greater peak hip external rotation muscle strength at six months contribute to impaired knee flexion angle excursion, quadriceps rate of torque development was the primary contributor to knee flexion angle excursion at both three and six months after surgery. Implementing strategies to maximize quadriceps rate of torque development during rehabilitation may help to reduce quadriceps avoidance gait after total knee arthroplasty.

The safety, efficacy and cost-effectiveness of the Maxm Skate, a lower limb rehabilitation device for use following total knee arthroplasty: study protocol for a randomised controlled trial

BACKGROUND

Physical rehabilitation is required to enhance functional outcomes and overall recovery following total knee arthroplasty (TKA). However, there are no universally accepted clinical guidelines available to consistently structure rehabilitation for TKA patients. A common method is rehabilitation provided in an outpatient setting, on a one-to-one treatment basis. This method is resource-intensive and outcomes must be compared to less costly alternatives such as home-based rehabilitation. The current study will analyse a novel home-based rehabilitation program. The Maxm skate is a portable, lower-limb, postoperative, rehabilitation exercise device for individual use in a hospital or home-based setting. This study was developed to compare the safety, efficacy and cost-effectiveness of the Maxm Skate rehabilitation program to standard rehabilitative care following TKA. The primary outcome is the range of motion (ROM) achieved by patients who received the Maxm Skate program compared to standard care at three months post TKA. Secondary outcomes include patient-reported outcomes, costs and functional evaluations which will be collected at multiple time-points up to 12 months after TKA.

METHODS

This is a single-blinded, randomised controlled trial (RCT) in which 116 eligible participants consented for primary TKA will be randomly allocated to receive either the Maxm Skate rehabilitation program or standard rehabilitative care. Fifty-eight participants per group will provide 90% power (α = 0.05) to detect 10° of difference in ROM between groups at three months after TKA, assuming a within-group standard deviation of 16° and allowing for 5% loss to follow-up. Participants randomised to the Maxm Skate group will use the skate device and accompanying iOS App and sensors to complete rehabilitation exercises, as outlined in the Maxm Skate Rehabilitation Guide. Outcomes will be compared to those receiving standard rehabilitative care. A blinded physiotherapist will evaluate functional outcomes preoperatively and at 2, 4, 6, 12, 26 and 52 weeks after TKA. The functional assessment will include measures of knee ROM, pain, isometric knee strength, balance and knee/thigh circumference. Limited measures will also be assessed at day 2 postoperatively by an alternate, unblinded physiotherapist. Clinical outcome measures will be administered preoperatively and at 6, 12 and 52 weeks postoperatively. An economic evaluation will be conducted and participants will be screened for adverse event occurrences from the time of consent to 12 months postoperatively.

DISCUSSION

This RCT will be the first to investigate the safety, efficacy and cost-effectiveness of the home-based Maxm Skate Rehabilitation program, in comparison to standard rehabilitative care following primary TKA.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12616001081404p . Registered on 11 August 2016.

Preoperative quadriceps weakness preferentially predicts postoperative aberrant movement patterns during high-demand mobility following total knee arthroplasty

BACKGROUND

Nearly all patients with total knee arthroplasty show aberrant movement patterns during tasks requiring greater joint demand compared to matched peers. Greater movement compensation leads to increased loading onto other joints, decreased functional capacity and limited reserve for independence later in life. Understanding how preoperative predictors contribute to postoperative aberrant movement patterns is needed to make better decisions for patients considering total knee arthroplasty.

METHODS

Forty-seven patients were tested preoperatively and six months following primary total knee arthroplasty. Demographic (age, sex, body mass), self-reported (knee pain, perception of physical performance, physical activity level), physical performance (quadriceps strength, lower limb power and timed stair climbing) and surgical metrics were collected as predictor variables. Three-dimensional models based on joint mechanic asymmetry during a decline walking task were collected at six months postoperatively. Decline walking is a preferred means to assess the surgical knee's contribution to limb performance during high-demand tasks. Bootstrap inclusion fraction was employed to compare the stability of each predictor variable prior to the final regression model.

RESULTS

Preoperative quadriceps strength (β = 0.33; p = 0.04) showed a significant relationship with knee extensor angular impulse during loading phase. No other predictor variable had any meaningful relationship with aberrant movement patterns (p > 0.05).

CONCLUSION

Our findings highlight patients' preoperative quadriceps strength as a meaningful predictor of postoperative performance. Preoperative quadriceps strength should be addressed when considering the knee's ability to contribute to higher demanding mobility tasks following surgery.

Sedentary Behavior in Patients With Knee Osteoarthritis Before and After Total Knee Arthroplasty: A Systematic Review

Objective:The objective of this systematic review is to integrate the available evidence on changes in sedentary behavior (SB) in patients with knee osteoarthritis after total knee arthroplasty (TKA).Methods:A systematic literature search from January 2002 to October 31, 2017, was performed for studies assessing objectively and/or subjectively measured SB following TKA. The Scottish Intercollegiate Guidelines Network Methodology appraisal tool was used to critically appraise the methodological quality of the included studies.Results:Ten studies reporting on SB with a total of 1,028 participants were included in the review. Three studies reported changes in SB with two showing a reduction in SB and one (with high risk of bias) an increase in SB after TKA. Seven studies showed no change in SB following TKA.Conclusion:Currently, there is insufficient evidence which suggests that SB time improves following TKA. Detailed assessments of SB after TKA are needed.

Is muscle strength in a painful limb affected by knee pain status of the contralateral limb? - Data from the Osteoarthritis Initiative

Contralateral knee pain has been suggested to be associated with muscle weakness in a pain-free knee, potentially through a mechanism of central nervous inhibition. Whether contralateral knee pain also affects muscle strength in a painful knee, however, is unknown. Here we study the extent to which isometric muscle strength differs between matched painful limbs of people with unilateral knee pain vs. matched painful limbs people with bilateral knee pain. To that end, 163 participants with unilateral knee pain were identified from the Osteoarthritis Initiative. Unilaterally painful (UP) limbs were defined as having numerical rating scale (NRS) ≥4/10, infrequent/frequent pain in the painful limb, while contralateral pain-free limbs were defined by NRS=0-1, no/infrequent pain and Western Ontario and McMaster Universities Arthritis Index (WOMAC) ≤1. The comparator group were matched bilaterally painful (BP) limbs. Maximum isometric muscle strength (N) was compared between 1:1 matched BP and UP limbs. Extensor strength was found to be lower in BP limbs than in UP limbs, (-2.9%; p=0.39) but this difference was not statistically significant. Extensor strength was significantly lower in the UP vs. contralateral pain-free limbs (-6.2%; p<0.001). No differences were observed between BP and contralateral painful limbs (0.6%; p=0.87). In conclusion, the current results identify a slight reduction of maximum knee extensor strength in a painful limb, when the contralateral knee is also painful. In contrast to pain-free limbs, this effect did not reach statistical significance, but the overall findings support the concept of central nervous inhibition of muscle strength by contralateral knee pain.

The effect of intensive exercise program and kinesiotaping following total knee arthroplasty on functional recovery of patients

Background

Total knee arthroplasty (TKA) is a gold standard for terminal term gonarthrosis patients in order to diminish pain, correct deformities, and regain stability. Postoperative functional recovery of patients depends on the current postoperative rehabilitation program to an important extent. The purpose of our study is to compare midterm functional level of gonarthrosis patients who were included in physiotherapy rehabilitation program following TKA with people in similar ages without any surgical indication nor intervention. We have aimed also to compare functionality of people who had additional kinesiotaping (KT) treatment with people who had conservative treatment only after knee arthroplasty.

Methods

Functional level and knee functionality of people in study were evaluated at the end of postoperative first month by 6-min walk test and Lysholm knee score respectively.

Results

There was no statistical difference between groups with and without TKA in terms of height, weight, body mass index, Lysholm score, and 6-min walk test score (p > 0.05). In patient group with TKA, people with postoperative KT treatment had greater 6-min walk test score for postoperative first month (p = 0.005).

Conclusion

TKA is considered a gold standard procedure in order to increase the quality of life and improve functionality of terminal term gonarthrosis patients. It is necessary to immediately control pain and edema of knee and apply intensive rehabilitation program aimed at muscle strengthening around hip and knee in order to increase the success of operation.

Quadriceps weakness preferentially predicts detrimental gait compensations among common impairments after total knee arthroplasty

Patients with total knee arthroplasty (TKA) have large deficits in physical performance in comparison to their healthy age-matched peers. Limb asymmetry stemming from less relative load borne by the surgical limb during daily mobility is associated with diminished performance and worsens with greater mobility demands. How common targets of postoperative care, such as muscle weakness, lower limb extension power, residual knee pain, and poor balance confidence can influence asymmetrical limb loading remains unclear. Forty-six patients with unilateral TKA underwent testing of impairments and motion analysis during 10° decline walking at 3 and 6 months postoperatively. At 3 months, only quadriceps femoris strength asymmetry was found to be significantly related to both total support moment (M_T ) (β = 0.431; p < 0.001) and knee extensor moment (M_K ) (β = 0.493; p < 0.001) asymmetry. Again at 6 months, only quadriceps strength asymmetry was related to M_T (β = 0.432; p < 0.001) and M_K (β = 0.534; p < 0.001) asymmetry. Quadriceps strength significantly improved over time in both limbs, however, deficits between limbs remained. Persistent quadriceps weakness is a key factor associated with walking compensation patterns that are limiting the capacity for greater physical performance of patients with TKA. The pronounced asymmetry in limb and knee loading at 3 months remains unchanged until at least 6 months after surgery, and its association with quadriceps strength asymmetry does not substantially change over time. While other factors may also prompt gait compensations, emphasis on improved quadriceps strength should be a focus of efforts to resolve gait compensations and enhance physical performance outcomes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2355-2363, 2018.

Restoring physical function after knee replacement: a cross sectional comparison of progressive strengthening vs standard physical therapy

Objective: The purpose of this study is to compare the functional status of patients 12 months after total knee arthroplasty (TKA) who underwent progressive strengthening or standard of care rehabilitation to older adults without knee joint pain. Methods: This cross-sectional design study included 165 participants in the progressive strengthening group, 40 participants in the standard of care group, and 88 older adults (control group). The Knee Outcome Survey - Activity of Daily Living, knee active range of motion (ROM), quadriceps strength, and performance tests were compared between groups using a one-way ANOVA. The proportions of participants in both TKA groups who achieved the lower bound of the 95% confidence interval of the control group were compared using a Fisher's exact test. Results: Significant between-group effects were found for all variables (p < 0.001). The control group had better outcomes than both the progressive strengthening and standard of care groups (p < 0.001). Compared to the standard of care group, a higher proportion of participants in the progressive strengthening group achieved the lower bound cutoff for active knee extension ROM (p = 0.042), quadriceps strength (p = 0.032), and stair climbing time (p = 0.029). Conclusion: More participants in the progressive strengthening group had physical function that was similar to the healthy control group, when compared to the standard of care group. Progressive strengthening rehabilitation may be more effective in restoring normative levels of function after TKA than standard of care.

Biomechanical characteristics of stair ambulation in patients with knee OA: A systematic review with meta-analysis toward a better definition of clinical hallmarks

BACKGROUND

Stair climbing was suggested to be the first affected task in individuals with knee osteoarthritis (OA).

RESEARCH QUESTION

This review aimed to identify consistent kinematic, kinetic, and spatiotemporal alterations of stair climbing exhibited by individuals with knee OA.

METHODS

A literature search published until September 2017 was conducted in PubMed, PEDro, CINAHL, and Cochrane CENTRAL. Reviewer extracted data in accordance with the Cochrane Handbook. Where possible, data were combined into a meta-analysis; the pooled standardized mean differences between individuals with knee OA and healthy adults were calculated using the random-effect model.

RESULTS

In total, 585 potentially relevant articles were selected, of which 12 (695 participants, mean age: 58.4 years) met the inclusion criteria. Meta-analysis revealed that kinematic and kinetic alterations during stair climbing associated with knee OA were lower external knee flexion moment in conjunction with a larger trunk/hip flexion angles and smaller knee flexion/ankle dorsiflexion angles. Individuals with knee OA showed a delayed quadriceps activation during stair ascent. A lack of evidence was detected for alterations in external knee adduction moment during stair climbing. Effect estimate in each meta-analysis was judged "very low" on the GRADE approach.

SIGNIFICANCE

No strong conclusion can be drawn because of the low quality of evidence; however, individuals with knee OA may exhibit altered kinematics and kinetics changes in sagittal plane during stair climbing, and have delayed quadriceps muscle activity. Further studies with adequate adjustment for confounders are warranted to facilitate clinical hallmarks of the knee OA, particularly in early stages of the disease.

Preoperative knee deformity and kinematics impact postoperative knee kinematics in total knee arthroplasty

BACKGROUND

The purpose of this study was to evaluate the relationship between the preoperative knee deformity/kinematic pattern and the postoperative knee kinematic pattern in posterior cruciate ligament substituting (PS)-total knee arthroplasty (TKA).

METHODS

This study involved 39 patients with medial osteoarthritis who underwent a primary PS-TKA using a computed-tomography-based navigation system. All the operations were performed by a single surgeon using a subvastus approach, modified gap technique and the same PS type of prosthesis (Genesis II™ total knee system, Smith & Nephew, Memphis, TN, USA). Knee deformity, kinematic pattern after capsule incision (preoperative knee kinematics), and kinematic pattern after implantation (postoperative knee kinematics) in PS-TKA were measured. Kinematic patterns were divided into two groups: a medial pivot group and a non-medial pivot group.

RESULTS

Preoperative varus knee deformity was significantly larger in the non-medial pivot group than in the medial pivot group (femorotibial angle: 184.7±6.4° vs. 180.8±3.9°, P<0.05). In addition, preoperative knee kinematics were conserved postoperatively, at a rate of 82% (P<0.01).

CONCLUSIONS

The severity of varus knee deformity and the preoperative knee kinematic pattern might have affected the postoperative knee kinematics in PS-TKA. This must be confirmed with a randomized controlled trial on a large population study.

LEVEL OF EVIDENCE

case control study, Level III.