Lower limb biomechanics in individuals with knee osteoarthritis before and after total knee arthroplasty surgery

A systematic comparative analysis of gait characteristics in patients undergoing total knee arthroplasty and unicompartmental knee arthroplasty: a review study

BACKGROUND

This study systematically reviews recent research comparing clinical outcomes and gait function changes in patients undergoing total knee arthroplasty (TKA) versus unicompartmental knee arthroplasty (UKA).

METHODS

A systematic search of the Web of Science, PubMed, and Embase databases was conducted, covering publications from January 2013 to September 2024, to identify studies evaluating changes in clinical scores and gait parameters in patients undergoing TKA or UKA. Following stringent selection criteria, data were synthesized from studies involving 171 TKA and 148 UKA patients, focusing on reported gait outcomes and aggregating findings for comprehensive analysis. Direct comparisons between TKA and UKA were performed to assess differences in clinical scores and gait parameters, aiming to elucidate the relative efficacy of each surgical approach and provide robust evidence for clinical decision-making.

RESULTS

Ten studies met the inclusion criteria for post-operative gait outcome comparisons between TKA and UKA, with seven studies also addressing clinical scores. One study reported greater improvement in WOMAC scores for the UKA group at 6 months post-operation (P < 0.05), while another found superior EQ-5D scores for UKA patients at 1 year post-surgery (P < 0.05). Conversely, five studies found no significant differences in clinical scores between groups at 1 year (P > 0.05). All ten studies assessed gait parameter recovery, with three studies showing no significant differences at 1 year (P > 0.05). However, seven studies identified superior gait recovery in the UKA group across various parameters, including walking speed, step and stride length, single support time, heel strike force, knee joint range of motion, knee flexion angles during different gait phases, peak knee adduction moment, peak tibial internal rotation moment, gait symmetry, and stride length symmetry (P < 0.05).

CONCLUSIONS

The analysis indicates that UKA offers certain advantages in post-operative gait improvements compared to TKA, though these do not translate into significant differences in conventional clinical scoring systems. To enhance the reliability and generalizability of these findings, future studies should involve larger-scale, prospective randomized controlled trials.

Long-term gait analysis in patients after total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Gait abnormalities have been described in patients after total knee arthroplasty (TKA), leading to the development of inter-joint coordination abnormalities and increased risk of falling. Such impairments have been reported to persist in the long-term, although the majority of studies assessed gait pattern especially in the first months after TKA.

RESEARCH QUESTION

What are the long-term gait impairments in patients after TKA compared to healthy age-matched subjects?

METHODS

A systematic search was conducted on MEDLINE/PubMed, EMBASE, CENTRAL and Scopus databases. Observational studies or randomized controlled trials investigating gait spatial-temporal, kinematic and kinetics parameters in a time-window longer than 6 months in patients with TKA compared to healthy age-matched subjects were included. Methodological quality was assessed using the modified Downs and Black (D&B) checklist and participants' characteristics, surgical procedures details and outcome measures were extracted. Pooled or un-pooled findings were categorized into "6 months - 1 year" and "more than 1 year" timepoint categories.

RESULTS

Twenty-eight studies (976 patients) were included. Overall quality was fair with a mean modified D&B score of 63.5 %. Reduced speed, stride length, cadence and longer stance phase were found in patients when compared to healthy individuals at "6 months - 1 year" follow-up. Spatial-temporal parameters deficits were also found at more than 1 year after TKA, where lower single-limb support and longer double-limb support durations were detected. These impairments occurred in concomitance with decreased knee range of motion along the sagittal and frontal planes and altered kinetic parameters. Hip kinematic and kinetic long-term impairments were also detected after TKA.

SIGNIFICANCE

These findings highlighted long-term gait pattern alterations in patients with TKA compared to age-matched healthy subjects. Future studies should identify interventions able to reduce long-term gait pattern alterations and improve function in patients after TKA.

Investigation of Biomechanical Differences in Level Walking between Patients with Bilateral and Unilateral Total Knee Replacements

Due to the high risk of a bilateral total knee arthroplasty (TKR) following unilateral TKR, this study was performed to investigate bilateral TKR patients. Specifically, we examined biomechanical differences between the first replaced and second replaced limbs of bilateral patients. Furthermore, we examined bilateral TKR effects on hip, knee, and ankle biomechanics, compared to the replaced and non-replaced limbs of unilateral patients. Eleven bilateral patients (70.09 ± 5.41 years, 1.71 ± 0.08 m, 91.78 ± 13.00 kg) and fifteen unilateral TKR patients (65.67 ± 6.18 years, 1.73 ± 0.10 m, 87.72 ± 15.70 kg) were analyzed while performing level walking. A repeated measures one-way ANOVA was performed to analyze between-limb differences within the bilateral TKR group. A 2 × 2 (limb × group) ANOVA was used to determine differences between bilateral and unilateral patients. Our results showed that the second replaced limb exhibited a lower peak initial-stance knee extension moment than the first replaced limb. No other kinematic or kinetic differences were found. Bilateral patients exhibited lower initial-stance knee extension moments, knee abduction moments, and dorsiflexion moments, compared to unilateral patients. Bilateral patients also exhibited lower push-off peak hip flexion moments and vertical GRF. The differences between the first and second replaced limbs of bilateral patients may indicate different adaptation strategies used following a second TKR. The significant group differences indicate that adaptations are different between these groups, and it is not recommended to use patients with unilateral and bilateral TKR together in gait analyses.

A preliminary study on analysis of lower limb energy during walking in the patients with knee replacement

Background

Knee replacement surgeries are used to reduce pain and enhance functionality for individuals with knee arthritis. It is predicted that the annual volume of total knee replacement surgeries conducted in the US will surge by a substantial 673% by 2030. Though a lot of studies have done gait analysis on patients with knee replacement, little research is on energy changes in the lower limbs during gait. This study aimed to investigate the mechanical energy changes in the lower limbs for patients with total knee arthroplasty (TKA) and unicondylar knee arthroplasty (UKA), and ultimately to provide a specific tool to analyze limb energy during gait in clinical practice.

Methods

10 TKA and 8 UKA patients were recruited for gait analysis. The control group consisted of 11 individuals without knee replacement surgery. Vicon motion capture system and Plug-in-Gait model were used to collect gait data to obtain marker coordinates and gait parameters. The kinetic energy, potential energy, and rotational energy for each segment in the lower limbs were calculated. The energies in the centre of pelvis were considered as the approximate to the centre of mass. The energy recovery coefficients were analysed for each segment during gait. SPSS was used to identify the differences between different groups.

Results

The results showed that during walking, the upper leg had the highest recovery coefficient, approximately 40%, followed by the foot at 10%, and the lowest recovery coefficient was observed in the lower leg, approximately 1-3%. However, the energy recovery coefficients at the centre of pelvis were significantly higher in the control group than the TKA and UKA groups by roughly 12%-15%.

Conclusions

The energy difference between the operative and non-operative sides is not significant regardless of the type of surgery. The TKA and UKA groups were more active in potential energy than control group. The upper leg has the highest recovery efficiency of kinetic and potential energy exchanges when walking. The control group used the energy for whole body is better than the patient groups. This study provides a new and useful way to analyze mechanical energy in the lower limbs during gait and could be applied in clinical practice.

Sagittal plane knee kinematics can be measured during activities of daily living following total knee arthroplasty with two IMU

Knee function is rarely measured objectively during functional tasks following total knee arthroplasty. Inertial measurement units (IMU) can measure knee kinematics and range of motion (ROM) during dynamic activities and offer an easy-to-use system for knee function assessment post total knee arthroplasty. However, IMU must be validated against gold standard three-dimensional optical motion capture systems (OMC) across a range of tasks if they are to see widespread uptake. We computed knee rotations and ROM from commercial IMU sensor measurements during walking, squatting, sit-to-stand, stair ascent, and stair descent in 21 patients one-year post total knee arthroplasty using two methods: direct computation using segment orientations (r_IMU), and an IMU-driven iCloud-based interactive lower limb model (m_IMU). This cross-sectional study compared computed knee angles and ROM to a gold-standard OMC and inverse kinematics method using Pearson's correlation coefficient (R) and root-mean-square-differences (RMSD). The r_IMU and m_IMU methods estimated sagittal plane knee angles with excellent correlation (>0.95) compared to OMC for walking, squatting, sit-to-stand, and stair-ascent, and very good correlation (>0.90) for stair descent. For squatting, sit-to-stand, and walking, the mean RMSD for r_IMU and m_IMU compared to OMC were <4 degrees, < 5 degrees, and <6 degrees, respectively but higher for stair ascent and descent (~12 degrees). Frontal and transverse plane knee kinematics estimated using r_IMU and m_IMU showed poor to moderate correlation compared to OMC. There were no differences in ROM measurements during squatting, sit-to-stand, and walking across the two methods. Thus, IMUs can measure sagittal plane knee angles and ROM with high accuracy for a variety of tasks and may be a useful in-clinic tool for objective assessment of knee function following total knee arthroplasty.

Gait speed and kinesiophobia explain physical activity level in adults with osteoarthritis: A cross-sectional study

Identifying potential contributing factors for physical inactivity in people with knee osteoarthritis is vital for designing practical activity promoting interventions. Walking is a common activity, but it is unknown how gait characteristics may influence physical activity and if psychological factors, specifically fear of movement (kinesiophobia), contribute to this relationship. The aim of our study was to investigate the contributions of select gait parameters and kinesiophobia to activity levels. Cross-sectional data from 40 participants (F 24|M 16; age 57.6 ± 8.9 years; BMI 34.7 ± 7.0 kg/m2 ) with uni- or bilateral knee osteoarthritis were included. Physical activity and kinesiophobia were assessed by self-report using the University of California, Los Angeles activity rating scale, and Tampa scale for kinesiophobia, respectively. Gait parameters were collected with three-dimensional gait analysis while participants walked on an instrumented split-belt treadmill at a self-selected speed. Higher peak sagittal plane joint moments at the ankle (ρ = 0.418, p = 0.007), and hip (ρ = 0.348, p = 0.028), faster self-selected gait speed (ρ = 0.553, p < 0.001), and less kinesiophobia or fear of movement (ρ = -0.695, p < 0.001) were independently related to higher physical activity level in adults with knee osteoarthritis. In hierarchical regression models, after accounting for covariates, only self-selected gait speed, and kinesiophobia significantly contributed to explaining the variation in physical activity level. Statement of clinical significance: Interventions aimed at improving physical activity participation in those with lower limb osteoarthritis should consider assessing the contribution of pain-related fear of movement.

Modern Patellofemoral Arthroplasty

INTRODUCTION

The ideal procedure for isolated patellofemoral arthritis is a controversial topic. Patellofemoral arthroplasty (PFA) is an option that aims to restore normal kinematics to the knee while preserving bone. PFA has been shown to have benefits compared with total knee arthroplasty (TKA) in this patient population but has historically had a high failure rate. Revision rates are improving with modern implants and tight indications but still remain higher than TKA. This review summarizes current thinking around PFA using modern implants and techniques in 2023, provides an implant-specific analysis, and assesses how we can improve outcomes after PFA based on the current literature. The aim was to provide an outline of the evidence around PFA on which surgeons can make decisions to optimize patient outcome in this young and active population.

METHODS

Four databases (MEDLINE, Embase, Scopus, and SPORTDiscus) were searched for concepts of patellofemoral joint arthroplasty. After abstract and text review, a screening software was used to assess articles based on inclusion criteria for studies describing indications, outcomes, and techniques for isolated PFA using modern implants, with or without concomitant procedures.

RESULTS

A total of 191 articles were included for further examination, with 62 articles being instructional course lectures, systematic reviews, technique articles, narrative reviews, expert opinions, or meta-analyses. The remaining articles were case reports, trials, or cohort studies. Articles were used to create a thorough outline of multiple recurrent topics in the literature.

CONCLUSIONS

PFA is an appealing option that has the potential to provide a more natural feeling and functioning knee for those with isolated PF arthritis. The high rate of revision is a cause for concern and there are several technical details that should be stressed to optimize results. The uncertain outcome after revision to TKA also requires more investigation. In addition, the importance of strict selection criteria and firm indications cannot be stressed enough to optimize longevity and attempt to predict those who are likely to have progression of tibiofemoral osteoarthritis. The development of new third-generation implants is promising with excellent functional outcomes and a much lower rate of maltracking and implant complications compared with earlier generations. The impact of these implants and improvement in surgical techniques on the revision rate of PFA will be determined from longer-term outcomes.

Stepping beyond Counts in Recovery of Total Knee Arthroplasty: A Prospective Study on Passively Collected Gait Metrics

Advances in algorithms developed from sensor-based technology data allow for the passive collection of qualitative gait metrics beyond step counts. The purpose of this study was to evaluate pre- and post-operative gait quality data to assess recovery following primary total knee arthroplasty. This was a multicenter, prospective cohort study. From 6 weeks pre-operative through to 24 weeks post-operative, 686 patients used a digital care management application to collect gait metrics. Average weekly walking speed, step length, timing asymmetry, and double limb support percentage pre- and post-operative values were compared with a paired-samples t-test. Recovery was operationally defined as when the respective weekly average gait metric was no longer statistically different than pre-operative. Walking speed and step length were lowest, and timing asymmetry and double support percentage were greatest at week two post-operative (p < 0.0001). Walking speed recovered at 21 weeks (1.00 m/s, p = 0.063) and double support percentage recovered at week 24 (32%, p = 0.089). Asymmetry percentage was recovered at 13 weeks (14.0%, p = 0.23) and was consistently superior to pre-operative values at week 19 (11.1% vs. 12.5%, p < 0.001). Step length did not recover during the 24-week period (0.60 m vs. 0.59 m, p = 0.004); however, this difference is not likely clinically relevant. The data suggests that gait quality metrics are most negatively affected two weeks post-operatively, recover within the first 24-weeks following TKA, and follow a slower trajectory compared to previously reported step count recoveries. The ability to capture new objective measures of recovery is evident. As more gait quality data is accrued, physicians may be able to use passively collected gait quality data to help direct post-operative recovery using sensor-based care pathways.

Comparison of spatiotemporal, kinematic, and kinetic gait characteristics in total and unicompartmental knee arthroplasty during level walking: A systematic review and meta-analysis

PURPOSE

This meta-analysis was performed to compare the spatiotemporal, kinematic, and kinetic gait characteristics during level walking between total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA).

METHODS

An electronic database literature search was performed to screen clinical trials which were included the studies evaluating not only spatiotemporal, kinematic, and kinetic gait parameters, but also knee range of motion and knee score (Knee Society Score and Oxford Knee Score, i.e., KSS and OKS). The data analysis was performed using statistical software Stata 14.0 and Review Manager 5.4.

RESULTS

Thirteen studies (369 knees) that met the criteria were eventually included in this meta-analysis. The results revealed significant differences between UKA and TKA with regard to walking speed (P = 0.04), stride length (P = 0.02), maximum knee flexion at loading (P = 0.001), the 1st peak of vert-GRF (P = 0.006), the 1st valley of vert-GRF (P = 0.007), knee internal rotational moment (P = 0.04), knee extension (P < 0.00001), and KSS Function score (P = 0.05). In contrast, there were no statistical differences in the remaining spatiotemporal, kinematic, and kinetic gait parameters.

CONCLUSION

Medial UKA design is superior to TKA design with regard to walking speed, stride length, maximum knee flexion at loading, the 1st peak and the 1st valley of vert-GRF, knee internal rotational moment, knee extension, and KSS Function score. And it could provide a stronger basis for physicians to make clinical decisions.

Study on the correlation between early three-dimensional gait analysis and clinical efficacy after robot-assisted total knee arthroplasty

PURPOSE

Robot-assisted technology is a forefront of surgical innovation that improves the accuracy of total knee arthroplasty (TKA). But whether the accuracy of surgery can improve the clinical efficacy still needs further research. The purpose of this study is to perform three-dimensional (3D) analysis in the early postoperative period of patients who received robot-assisted total knee arthroplasty (RATKA), and to study the trend of changes in gait parameters after RATKA and the correlation with the early clinical efficacy.

METHODS

Patients who received RATKA in the Center of Joint Surgery, the First Hospital Affiliated to Army Military Medical University from October 2020 to January 2021 were included. The imaging parameters, i.e., hip-knee-ankle angle, lateral distal femoral angle, medial proximal tibial angle, posterior condylar angle were measured 3 months post-TKA. The 3D gait analysis and clinical efficacy by Western Ontario Mac Master University Index (WOMAC) score were performed pre-TKA, 3 and 6 months post-TKA. The differences in spatiotemporal parameters of gait, kinetic parameters, and kinematic parameters of the operated limb and the contralateral limb were compared. The correlation between gait parameters and WOMAC scores was analyzed. Paired sample t-test and Wilcoxon rank-sum test were used to analyze the difference between groups, and Spearman correlation coefficient was used to analyze the correlation.

RESULTS

There were 31 patients included in this study, and the imaging indexes showed that all of them returned to normal post-TKA. The WOMAC score at 3 months post-TKA was significantly lower than that pre-TKA, and there was no significant difference between at 3 and 6 months. The 3D gait analysis results showed that the double support time of the operated limb reduced at 3 and 6 months (all p < 0.05), the maximum extension and maximum external rotation of the knee joint increased at stance phase, and the maximum flexion angle, the range of motion and the maximum external rotation increased at swing phase. Compared with the preoperative data, there were significant improvements (all p < 0.05). Compared with the contralateral knee joint, the maximum external rotation of the knee joint at swing phase was smaller than that of the contralateral side, and the maximum flexion and extension moment was greater than that of the contralateral knee. The maximum external rotation moment of the joint was greater than that of the contralateral knee joint (p < 0.05). There was a negative correlation between the single support time pre-TKA and the WOMAC score at 3 months (p = 0.017), and the single support time at 3 months was negatively correlated with the WOMAC score at 6 months (p = 0.043). The cadence at 6 months was negatively correlated with the WOMAC score at 6 months (p = 0.031). The maximum knee extension at stance phase at 6 months was negatively correlated with the WOMAC score at 6 month (p = 0.048). The maximum external rotation at stance phase at 6 months was negatively correlated with the WOMAC score at 6 months (p = 0.024).

CONCLUSION

The 3D gait analysis of RATKA patients is more sensitive than WOMAC score in evaluating the clinical efficacy. Trend of changes in gait parameters shows that the knee joint support, flexion and extension function, range of motion, external rotation and varus deformity moment of the patient were significantly improved at 3 months after surgery, and continued to 6 months after surgery. Compared with the contralateral knee, the gait parameters of the operated limb still has significant gaps in functionality, such as the external rotation and flexion and extension. The single support time, cadence, knee extension, and knee external rotation of the operated limb have a greater correlation with the postoperative WOMAC score. Postoperative rehabilitation exercises should be emphasized, which is of great value for improving the early efficacy of RATKA.

Sway and Acceleration Changes of the Center of Mass during Walking Stance Phase before and after Total Knee Arthroplasty

Elucidating the sway and changes in the acceleration of center of mass (COM) during walking is important for effective gait training and rehabilitation. The objective of this study was to verify the improvement in gait before and after total knee arthroplasty (TKA) from COM sway and the changes in the acceleration of COM during the stance phase of walking. This study included 13 patients (1 male and 12 females) with medial knee osteoarthritis who were hospitalized for TKA. The COM sway during the stance phase of walking was evaluated using root mean square (RMS) normalized by walking speed, and the changes in acceleration were further verified. Lateral and vertical RMS showed significant differences between preoperative and postoperative states and demonstrated low values after TKA. The lateral acceleration at the latter part of the early stance phase demonstrated a significant difference between preoperative and postoperative states. A significant difference was also observed in the lateral acceleration in the late stance phase between the two groups. Improvement in pain and alignment after TKA reduced the lateral sway of COM and the changes in acceleration during the gait stance phase, which is speculated to lead to improvement in gait and prevention of falls.

Efficacy of Visual Feedback Training for Motor Recovery in Post-Operative Subjects with Knee Replacement: A Randomized Controlled Trial

To evaluate the effects of visual feedback training on motor recovery in postoperative patients with a total knee replacement (TKR). The performance of 40 first-ever TKR patients (27 females; mean age: 70.5 (67.2−74.0) years) was evaluated in a single center, single-blind, randomized controlled study. The patients were randomly and equally distributed into two demographically/clinically matched groups undergoing experimental or traditional treatments. All patients have been treated in a 1 h session, 2/day for 5 days a week, for six consecutive weeks. The first group (“control”) underwent conventional physical therapy, whereas the experimental group received advanced knee training with visual feedback using the TecnoBody® device (Walker View 3.0 SCX, Dalmine (BG), Italy). The clinical scales and kinematic parameters coming from the gait analysis were evaluated to demonstrate the dynamic balance function in a standing position before and after each treatment. After the treatment, both experimental and control groups improved significantly and similarly, as measured by the clinical scales (Numeric Rating Scale for Pain and Barthel index). A significant boosting of the motor performance was detected in the experimental group with respect to the control group in the terms of symmetry index 84 (80.8−85.4) vs. 87.15 (84−92.8) p = 0.001 *; single stance support 34.9 (34.1−36.5) vs. 37.8 (36.6−38.9); p < 0.001; and obliquity parameters 58.65 (51.3−70.3) vs. 73 (62.3−82.1); p < 0.001. Applying visual feedback training in addition to traditional rehabilitation strategies improves the knee function and motor control in postoperative TKR patients.

Lower limb inter-joint coordination in individuals with osteoarthritis before and after a total knee arthroplasty

BACKGROUND

Total knee arthroplasty is the most common treatment for severe knee osteoarthritis. Coordination and variability analyses are effective measures of the injury stage or rehabilitation process. This study compared the inter-joint coordination before and after arthroplasty, compared to controls.

METHODS

Twenty-seven patients were evaluated before and 12 months after surgery, compared to 27 controls. Coordination and variability in the sagittal plane between the hip-knee and knee-ankle were calculated using vector coding and circular statistics. Coordination was categorized as in-phase, anti-phase, or distal or proximal joint-phase. The gait cycle was divided into sub-phases for the coordination, variability, and range of motion results.

FINDINGS

Coordination and range of motion differed significantly between the patient groups and controls, while small differences between pre- and post-operative groups were also detected. The hip-knee showed a reduced in-phase frequency in the patient group compared to control during stance, particularly mid-stance: pre-operative 24.3% ± 33.9, post-operative 29.5 ± 29.7, and controls 70.7 ± 17.0. This difference was compensated for by increasing proximal-phase (hip) frequency in the patient groups. For knee-ankle coordination, the patient groups showed higher distal-phase (ankle) frequency during the early and mid-stance. Coordination variability was higher post-operatively during swing and terminal swing phases, compared to controls.

INTERPRETATION

The results indicated reduced degrees of freedom for the knee during stance phase with a reduced capacity to move the knee and hip in opposing directions before and one year after surgery. The patient group after the surgery increased knee range of motion and coordination compared to pre-operative during swing phase.

Intersegmental Coordination in Patients With Total Knee Arthroplasty During Walking

Precise identification of deficient intersegmental coordination patterns and functional limitations is conducive to the evaluation of surgical outcomes after total knee arthroplasty (TKA) and the design of optimal personalized rehabilitation protocols. However, it is still not clear how and when intersegmental coordination patterns change during walking, and what functional limitations are in patients with TKA. This study was designed to investigate lower limb intersegmental coordination patterns in patients with knee osteoarthritis before and after TKA and identify how intersegmental coordination of patients is altered during walking before and after TKA. It was hypothesized that 6-month after TKA, intersegmental coordination patterns of patients are improved compared with that before TKA, but still do not recover to the level of healthy subjects. Gait analysis was performed on 36 patients before and 6-month after TKA and on 34 healthy subjects. Continuous relative phase (CRP) derived from the angle-velocity phase portrait was used to measure the coordination between interacting segments throughout the gait cycle. Thigh-shank CRP and shank-foot CRP were calculated for each subject. Statistical parametric mapping (SPM), a one-dimensional analysis of the entire gait cycle curve, was performed directly to determine which periods of the gait cycle were different in patients and healthy subjects. Six-month after TKA, thigh-shank CRP was significantly higher during 5–12% of the gait cycle (p = 0.041) and lower during 44–95% of the gait cycle (p < 0.001) compared with healthy subjects, and was significantly higher during 62–91% of the gait cycle (p = 0.002) compared with pre-operation. Shank-foot CRP was significantly lower during 0–28% of the gait cycle (p < 0.001) and higher during 58–94% of the gait cycle (p < 0.001) compared with healthy subjects, and was significantly lower during 3–18% of the gait cycle (p = 0.005) compared with pre-operation. This study found that patients exhibited altered intersegmental coordination during the loading response and swing phase both before and after TKA. Six-month after TKA, the thigh-shank coordination was partially improved compared with pre-operation, but still did not recover to the level of healthy subjects, while there was no improvement in the shank-foot coordination pattern after TKA compared with pre-operation. CRP combined with SPM methods can provide insights into the evaluation of surgical outcomes and the design of rehabilitation strategy.

Knee biomechanics of patients with total knee replacement during downhill walking on different slopes

PURPOSE

The purpose of this study was to compare knee biomechanics of the replaced limb to the non-replaced limb of total knee replacement (TKR) patients and healthy controls during walking on level ground and on decline surfaces of 5°, 10°, and 15°.

METHODS

Twenty-five TKR patients and 10 healthy controls performed 5 walking trials on different decline slopes on a force platform and an instrumented ramp system. Two analyses of variance, 2 × 2 (limb × group) and 2 × 4 (limb × decline slope), were used to examine selected biomechanics variables.

RESULTS

The replaced limb of TKR patients had lower peak loading-response and push-off knee extension moment than the non-replaced and the matched limb of healthy controls. No differences were found in loading-response and push-off knee internal abduction moments among replaced, non-replaced, and matched limb of healthy controls. The knee flexion range of motion, peak loading-response vertical ground reaction force, and peak knee extension moment increased across all slope comparisons between 0° and 15° in both the replaced and non-replaced limb of TKR patients.

CONCLUSION

Downhill walking may not be appropriate to include in early stage rehabilitation exercise protocols for TKR patients.

Clinical and objective gait outcomes remained stable seven years after total knee arthroplasty: A prospective longitudinal study of 28 patients

BACKGROUND

There is a paucity of data on mid to long-term gait outcomes after total knee arthroplasty. The aims of this longitudinal study were: to assess the evolution of both clinical and gait outcomes before and up to seven years after primary total knee arthroplasty (TKA) in a cohort of patients with knee osteoarthritis.

METHODS

This study included 28 patients evaluated before and up to seven years after primary TKA with both gait analysis and patient reported outcomes; of these, 20 patients were evaluated one year after surgery as well. Kinematic outcomes during gait (gait velocity, dimensionless gait veolicity, maximal knee flexion and knee range of motion), pain relief, Western Ontario and MacMaster Osteoarthritis Index (WOMAC), quality of life and patient satisfaction were assessed and compared at each visit with the paired Wilcoxon signed rank test (p < 0.05).

RESULTS

The significant improvement achieved at one year after TKA was stable up to seven years after surgery, with all clinical and kinematic outcomes unchanged, except for gait velocity, with a significant decrease over time (1.3 (1.1-1.4) m/s one year after TKA versus 1.0 (0.9-1.1) m/s, p < 0.05 up to seven years after).

CONCLUSION

Patients with knee osteoarthritis significantly improve their clinical and kinematic outcomes at one year postoperatively and maintain the gain up to seven years after primary TKA, except for gait velocity which decreases over time, most likely along with ageing.

Principal Component Analysis of Knee Joint Differences Between Bilateral and Unilateral Total Knee Replacement Patients During Level Walking

Many unilateral total knee replacement (TKR) patients will need a contralateral TKR. Differences in knee joint biomechanics between bilateral patients and unilateral patients are not well established. The purpose of this study was to examine knee joint differences in level walking between bilateral and unilateral patients, and asymptomatic controls, using principal component analysis. Knee joints of 1st replaced limbs of 15 bilateral patients (69.40 ± 5.04 years), 15 replaced limbs of unilateral patients (66.47 ± 6.15 years), and 15 asymptomatic controls (63.53 ± 9.50 years) were analyzed during level walking. Principal component analysis examined knee joint sagittal- and frontal-plane kinematics and moments, and vertical ground reaction force (GRF). A one-way analysis of variance analyzed differences between principal component scores of each group. TKR patients exhibited more flexed and abducted knees throughout stance, decreased sagittal knee range of motion (ROM), increased early-stance adduction ROM, decreased loading-response knee extension and push-off knee flexion moments, decreased loading-response and push-off peak knee abduction moment (KAbM), increased KAbM at midstance, increased midstance vertical GRF, and decreased loading-response and push-off vertical GRF. Additionally, bilateral patients exhibited reduced sagittal knee ROM, increased adduction ROM, decreased sagittal knee moments throughout stance, decreased KAbM throughout stance, an earlier loading-response peak vertical GRF, and a decreased push-off vertical GRF, compared to unilateral patients. TKR patients, especially bilateral patients had stiff knee motion in the sagittal-plane, increased frontal-plane joint laxity, and a quadriceps avoidance gait.

How to compare knee kinetics at different walking speeds?

BACKGROUND

Walking speed is a confounding factor in biomechanical analyses of gait, but still many studies compare gait biomechanics at comfortable walking speed (CWS) that is likely to differ between groups or conditions. To identify gait deviation unrelated to walking speed, methods are needed to correct biomechanical data over the gait cycle for walking speed.

RESEARCH QUESTION

How to compare knee kinetics over the gait cycle at different walking speeds?

METHODS

22 asymptomatic subjects walked on a dual-belt treadmill at CWS and 4 fixed speeds. Knee moments in sagittal (KFM) and frontal plane (KAM) were calculated via inverse dynamics. The net moment differences between CWS and fixed speed were expressed as a root-mean-square error (RMSE) normalized to the range of the variable. Two methods to correct for walking speed were compared. In method 1, KFM and KAM values were estimated based on interpolation between speeds at each percentage of the gait cycle. In method 2, principal component analysis was used to extract speed related features to reconstruct KFM and KAM at the speed of interest. The accuracy of both methods was tested using a leave-one-out cross validation.

RESULTS

Walking speed influenced the magnitude and shape of KFM and KAM. To account for these speed influences using both methods, leave-one-out cross validation showed low normalized RMSE (< 5 %), with little difference between the two methods. RMSE for both reconstruction methods were up to 60 % lower than the RMSE between CWS and fixed speed.

SIGNIFICANCE

Both methods could accurately correct knee kinetics over the gait cycle for the effects of walking speed. Walking speed dependency should be incorporated in each gait laboratory's reference dataset to be able to identify gait deviations unrelated to gait speed.

Overground Walking Biomechanics of Dissatisfied Persons With Total Knee Replacements

Patient dissatisfaction following total knee replacement (TKR) procedures is likely influenced by both subjective and objective aspects. Increased pain and reduced performance on clinical tests have been shown in persons who are dissatisfied with the outcome of their surgery. However, it is unknown how overground walking kinematics and kinetics might differ in the dissatisfied versus satisfied patients following TKR surgery. This study compared the lower-extremity walking kinematics and kinetics of patients dissatisfied with their TKR to that of satisfied patients and healthy controls. Thirty nine subjects completed walking trials, including nine dissatisfied and 15 satisfied TKR patients and 15 healthy controls. A 2 × 3 repeated -measures analysis of variance was used to assess differences between groups and limbs (P < .05). Dissatisfied persons showed significantly reduced loading-response and push-off peak vertical ground reaction forces, flexion range of motion, loading-response extension moments, and loading-response abduction moments compared to the controls. Peak loading-response and push-off vertical ground reaction forces and flexion range of motion were reduced in the replaced limb of dissatisfied patients compared with their nonreplaced limb. Push-off plantar flexion moments were reduced in the dissatisfied patients compared with the satisfied and healthy controls. Dissatisfied patients also reported increased knee joint pain and reduced preferred gait speed. Moreover, dissatisfied patients experienced mechanical limb asymmetries not present in those satisfied with their surgery result. Thus, patients dissatisfied with their total knee replacement outcome were found to be experiencing significant negative physiological changes.

Total knee arthroplasty for patients with medial knee osteoarthritis improves trunk movement during gait

BACKGROUND

Previous studies have indicated that the kinematics of the knee joint affect the trunk and pelvis during gait. However, the factors that influence trunk movement in knee osteoarthritis patients during gait after surgery remain unclear.

OBJECTIVE

To examine the effect of total knee arthroplasty (TKA) on trunk movement during gait by comparing knee osteoarthritis patients with healthy controls.

METHODS

Fourteen medial knee osteoarthritis patients who underwent initial unilateral TKA and 11 controls participated in this study. Knee and hip joint flexion and trunk and pelvic tilts during gait were acquired using a three-dimensional motion analysis system. Knee joint range of motion, pain, and kinematic data were collected preoperatively and 1 year postoperatively for knee osteoarthritis patients.

RESULTS

Knee extension limitation and pain significantly improved postoperatively compared with preoperative stages. Preoperatively, the peak anterior trunk tilt during the stance phase was significantly larger in osteoarthritis patients than in controls. The peak anterior trunk tilt during the stance phase was significantly smaller postoperatively than at preoperative stages.

CONCLUSIONS

These results suggest that after TKA, the trunk movements of knee osteoarthritis patients were approximately equal to those of controls, with improvement in clinical outcomes such as knee extension limitation and pain.

Matching walking speed of controls affects identification of gait deviations in patients with a total knee replacement

BACKGROUND

The assessment of functional recovery of patients after a total knee replacement includes the quantification of gait deviations. Comparisons to comfortable gait of healthy controls may incorrectly suggest biomechanical gait deviations, since the usually lower walking speed of patients already causes biomechanical differences. Moreover, taking peak values as parameter might not be sensitive to actual differences. Therefore, this study investigates the effect of matching walking speed and full-waveform versus discrete analyses.

METHODS

Gait biomechanics of 25 knee replacement patients were compared to 22 controls in two ways: uncorrected and corrected for walking speed employing principal component analyses, to reconstruct control gait biomechanics at walking speeds matched to the patients. Ankle, knee and hip kinematics and kinetics were compared over the full gait cycle using statistical parametric mapping against using peak values.

FINDINGS

All joint kinematics and kinetics gait data were impacted by applying walking speed correction, especially the kinetics of the knee. The lower control walking speeds used for reference generally reduced the magnitude of differences between patient and control gait, however some were enlarged. Full-waveform analysis identified greater deviating gait cycle regions beyond the peaks, but did not make peak value analyses redundant.

INTERPRETATION

Matching walking speed of controls affects identification of gait deviations in patients with a total knee replacement, reducing deviations confounded by walking speed and revealing hidden gait deviations related to possible compensations. Full-waveform analysis should be used along peak values for a comprehensive quantification of differences in gait biomechanics.

Quantifying Achievable Levels of Improvement in Knee Joint Biomechanics During Gait After Total Knee Arthroplasty Relative to Osteoarthritis Severity

Total knee arthroplasty (TKA) surgery improves knee joint kinematics and kinetics during gait for most patients, but a lack of evidence exists for the level and incidence of improvement that is achieved. The objective of this study was to quantify patient-specific improvements in knee biomechanics relative to osteoarthritis (OA) severity levels. Seventy-two patients underwent 3-dimensional (3D) gait analysis before and 1 year after TKA surgery, as well as 72 asymptomatic adults and 72 with moderate knee OA. A combination of principal component analysis and discriminant analyses were used to categorize knee joint biomechanics for patients before and after surgery relative to asymptomatic, moderate, and severe OA. Post-TKA, 63% were categorized with knee biomechanics consistent with moderate OA, 29% with severe OA, and 8% asymptomatic. The magnitude and pattern of the knee adduction moment and angle (frontal plane features) were the most significant contributors in discriminating between pre-TKA and post-TKA knee biomechanics. Standard of care TKA improves knee biomechanics during gait to levels most consistent with moderate knee OA and predominately targets frontal plane features. These results provide evidence for the level of improvement in knee biomechanics that can be expected following surgery and highlight the biomechanics most targeted by surgery.

Walking Speed and Maximal Knee Flexion During Gait After Total Knee Arthroplasty: Minimal Clinically Important Improvement Is Not Determinable; Patient Acceptable Symptom State Is Potentially Useful

BACKGROUND

Total knee arthroplasty (TKA) is the operation of choice in patients with end-stage knee osteoarthritis (OA). Up to 1 in 5 patients still encounter functional limitations after TKA, partly explaining patient dissatisfaction. Which gait ability to target after TKA remains unclear. To determine whether Minimal Clinical Important Improvement (MCII) or Patient Acceptable Symptom State (PASS) values could be derived from gait parameters recorded in patients with TKA. And, if so, to define those values.

METHODS

In this ancillary study, we retrospectively analyzed gait parameters of patients scheduled for a unilateral TKA between 2011 and 2013. We investigated MCII and PASS values for walking speed and maximal knee flexion using anchor-based methods: 5 anchoring questions based on perceived body function and patients' satisfaction.

RESULTS

Over the study period, 79 patients performed a clinical gait analysis the week before and 1 year after surgery, and were included in the present study. All clinical and gait parameters improved 1 year after TKA. Nevertheless, changes in gait outcomes were not associated with perceived body function or patients' satisfaction, precluding any MCII estimation in gait parameters. PASS values, however, could be determined as 1.2 m/s for walking speed and 50° for maximal knee flexion.

CONCLUSION

In this study, we found that MCII and PASS values are not necessarily determinable for gait parameters after TKA in patients with end-stage OA. Using anchor questions based on perceived body function and patient's satisfaction, MCII could not be defined while PASS values were potentially useful.

LEVEL OF EVIDENCE

Level III.

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.

Advanced functional biomechanical analysis of medial rotation knee arthroplasty

BACKGROUND

The Medacta GMK-Sphere total knee arthroplasty (TKA) is designed to mimic the movements and stabilimidty of a natural knee for optimal post-operative function and mobility. This study aimed to quantify the early functional outcome of patients with this implant.

METHODS

Patients due to undergo TKA to treat end-stage osteoarthritis were recruited into this study. Functional tests of knee range of motion (ROM), strength, and gait kinematics were carried out pre-operatively and one year post-operatively at routine clinics. Motion capture technology and a force transducer were used to collect all data. Normality tests were completed on all data sets to confirm normal distribution of the data, then paired t-tests were used to statistically compare the results. The level of significance was set as α = 0.05.

RESULTS

Sixty-three patients underwent pre-operative assessments; of which 30 returned one year post-operatively and consented to have follow-up testing. The operative knee was found to have poorer function than the contralateral knee pre-operatively (p < 0.05). Post-operatively, knee ROM significantly improved on the operative side to a mean of 116.1 ± 19.0. Gait kinematics also improved, especially in the frontal plane, but some abnormal traits remained in the sagittal plane. Knee strength decreased post-operatively.

CONCLUSIONS

The Medacta GMK-Sphere TKA improves knee range of motion sufficiently within the first postoperative year to allow patients to carry out most activities of daily living (>110° knee flexion), but continued poor knee strength may limit their abilities to complete tasks which are more biomechanically demanding than walking.

Leg-amplitude differentiation guided by haptic and visual feedback to detect alterations in motor flexibility due to Total Knee Replacement

Following total knee replacement (TKR), patients often persist in maladaptive motor behavior which they developed before surgery to cope with symptoms of osteoarthritis. An important challenge in physical therapy is to detect, recognize and change such undesired movement behavior. The goal of this study was to measure the differences in clinical status of patients pre-TKR and post-TKR and to investigate if differences in clinical status were accompanied by differences in the patients'' motor flexibility. Eleven TKR participants were measured twice: pre-TKR and post-TKR (twenty weeks after TKR). In order to infer maladaptation, the pre-TKR and post-TKR measurements of the patient group were separately compared to one measurement in a control group of fourteen healthy individuals. Clinical status was measured with the Visual Analogue Scale (VAS) for pain and knee stiffness and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Furthermore, Lower-limb motor flexibility was assessed by means of a treadmill walking task and a leg-amplitude differentiation task (LAD-task) supported by haptic or visual feedback. Motor flexibility was measured by coordination variability (standard deviation (SD) of relative phase between the legs) and temporal variability (sample entropy) of both leg movements. In the TKR-group, the VAS-pain and VAS- stiffness and the subscales of the KOOS significantly decreased after TKR. In treadmill walking, lower-limb motor flexibility did not significantly change after TKR. Between-leg coordination variability was significantly lower post-TKR compared to controls. In the LAD-task, a significant decrease of between-leg coordination variability between pre-TKR and post-TKR was accompanied by a significant increase in temporal variability. Post-TKR-values of lower-limb flexibility approached the values of the control group. The results demonstrate that a clinically relevant change in clinical status, twenty weeks after TKR, is not accompanied by alterations in lower-limb motor flexibility during treadmill walking but is accompanied by changes in motor flexibility towards the level of healthy controls during a LAD-task with visual and haptic feedback. Challenging patients with non-preferred movements such as amplitude differentiation may be a promising tool in clinical assessment of motor flexibility following TKR.

A musculoskeletal modelling approach to explain sit-to-stand difficulties in older people due to changes in muscle recruitment and movement strategies

By 2050 the proportion of over 65s is predicted to be 20% of the population. The consequences of an age-related reduction in muscle mass have not been fully investigated and, therefore, the aim of the present study was to quantify the muscle and joint contact forces using musculoskeletal modelling, during a sit-to-stand activity, to better explain difficulties in performing everyday activities for older people. A sit-to-stand activity with and without the use of arm rests was observed in ninety-five male participants, placed into groups of young (aged 18-35 years), middle-aged (aged 40-60 years) or older adults (aged 65 years and over). Older participants demonstrated significantly lower knee extensor and joint forces than the young when not using arm rests, compensating through elevated hip extensor and ankle plantarflexor muscle activity. The older group were also found to have higher shoulder joint contact forces whilst using arm rests. This tendency to reorganise muscle recruitment to include neighbouring groups or other parts of the body could make everyday activities more susceptible to age-related functional decline. Reductions in leg strength, via age- or atrophy- related means, creates increased reliance on the upper body and may result in further lower limb atrophy through disuse. The eventual decline of upper body function reduces strength reserves, leading to increased vulnerability, dependence on others and risk of institutionalisation.

Quantitative evaluation of gait features after total knee arthroplasty: Comparison with age and sex-matched controls

BACKGROUND

Gait function after total knee arthroplasty (TKA) is suboptimal. However, quantified analysis with comparing a control group is lacking.

RESEARCH QUESTION

The aims of this study were 1) to compare the gait before and after TKA and 2) to compare postoperative gait to that of an age-sex matched control group.

METHODS

This study consisted of 46 female and 38 male patients with end-stage knee osteoarthritis who underwent bilateral TKA, and 84 age- and sex-matched controls without knee pain and osteoarthritis. Seven gait parameters, including lower extremity alignment, knee adduction moment (KAM), knee flexion angle, external knee flexion moment, hip adduction angle, external hip adduction moment, and the varus-valgus arc during the stance phase, were collected using a commercial opto-electric gait analysis system. Principal component analysis was used for data processing and the standardized mean differences (SMDs) of the principal component scores were compared.

RESULTS

The most significant gait change after TKA was the alignment (SMD 1.62, p < 0.001). The average stance phase alignment changed from varus 7.3° to valgus 0.5°. The second significant change was a decrease of the KAM (SMD 1.08, p < 0.001). These two features were closely correlated (r = 0.644, p < 0.001). The gait feature that differed most from the controls was the varus-valgus arc during the stance phase (SMD 1.68, p < 0.001), which was constrained by 31% after TKA (p < 0.001) and was only 37% compared to the controls (p < 0.001).

SIGNIFICANCE

Improvement in gait after TKA was obtained through alignment correction. However, TKA significantly constrained coronal knee motion. TKA improved gait suboptimally; the gait was significantly different from that of controls.

Evaluation of the Painful Total Knee Arthroplasty

Total knee arthroplasty (TKA) has been associated with notable improvements in health-related quality of life of patients with end-stage knee arthritis. Although most patients experience substantial symptomatic relief after TKA, up to 19% of patients are unsatisfied with their outcome. With the dramatic, projected increase in the number of TKAs performed annually, it is crucial to appreciate the various modes of failure associated with this procedure. A comprehensive understanding of the symptomatology and thorough clinical examination aid in identifying the etiology of ongoing knee pain. Ancillary testing including conventional laboratory analyses, imaging studies, and diagnostic injections supplement a thorough history and physical examination. In addition, novel laboratory markers, RNA/DNA-based tests, and novel imaging modalities are emerging as beneficial tools in evaluating patients with a painful TKA. A well-structured, algorithmic approach in the management of these patients is essential in correctly diagnosing the patient and optimizing clinical outcomes.

Which osteoarthritic gait features recover following total knee replacement surgery?

Background

Gait analysis can be used to measure variations in joint function in patients with knee osteoarthritis (OA), and is useful when observing longitudinal biomechanical changes following Total Knee Replacement (TKR) surgery. The Cardiff Classifier is an objective classification tool applied previously to examine the extent of biomechanical recovery following TKR. In this study, it is further developed to reveal the salient features that contribute to recovery towards healthy function.

Methods

Gait analysis was performed on 30 patients before and after TKR surgery, and 30 healthy controls. Median TKR follow-up time was 13 months. The combined application of principal component analysis (PCA) and the Cardiff Classifier defined 18 biomechanical features that discriminated OA from healthy gait. Statistical analysis tested whether these features were affected by TKR surgery and, if so, whether they recovered to values found for the controls.

Results

The Cardiff Classifier successfully discriminated between OA and healthy gait in all 60 cases. Of the 18 discriminatory features, only six (33%) were significantly affected by surgery, including features in all three planes of the ground reaction force (p<0.001), ankle dorsiflexion moment (p<0.001), hip adduction moment (p = 0.003), and transverse hip angle (p = 0.007). All but two (89%) of these features remained significantly different to those of the control group after surgery.

Conclusions

This approach was able to discriminate gait biomechanics associated with knee OA. The ground reaction force provided the strongest discriminatory features. Despite increased gait velocity and improvements in self-reported pain and function, which would normally be clinical indicators of recovery, the majority of features were not affected by TKR surgery. This TKR cohort retained pre-operative gait patterns; reduced sagittal hip and knee moments, decreased knee flexion, increased hip flexion, and reduced hip adduction. The changes that were associated with surgery were predominantly found at the ankle and hip, rather than at the knee.

Biomechanics and wear comparison between mechanical and kinematic alignments in total knee arthroplasty

The uses of mechanical and kinematic alignments in total knee arthroplasty are under debate in recent clinical investigations. In this study, the differences in short-term biomechanics and long-term wear volume between mechanical and kinematic alignments in total knee arthroplasty were investigated, based on a subject-specific musculoskeletal multi-body dynamics model during walking gait simulation. An increase of 8.2% in the peak tibiofemoral medial contact force, a posterior contact translation by maximum 4.7 mm and a decrease of 5.5% in the wear volume after a 10-million-cycle simulation were predicted in the kinematic alignment, compared with the mechanical alignment. Nevertheless, the tibiofemoral contact mechanics, the range of motions and the long-term wear were not markedly different between mechanical and kinematic alignments. Furthermore, the mechanical alignment with a posterior tibial slope similar to that under the kinematic alignment was found to produce similar anterior-posterior translation and the range of motion, and an approximate wear volume, compared with the kinematic alignment. The ligament forces under the kinematic alignment were influenced markedly by as much as 25%, 50% and 77% for the medial collateral ligament, lateral collateral ligament and posterior cruciate ligament forces, respectively. And, a maximum increase of 40% for patellofemoral contact force was predicted under the kinematic alignment. These findings suggest that the kinematic alignment is an alternative alignment principle but no marked advantages in biomechanics and wear to the mechanical alignment. The adverse effects of the kinematic alignment on patella loading and soft tissue forces should be noticed.

The effect of low-level laser therapy and physical exercise on pain, stiffness, function, and spatiotemporal gait variables in subjects with bilateral knee osteoarthritis: a blind randomized clinical trial

Objective: To evaluate the effects of individual and combination therapies (low-level laser therapy and physical exercises) on pain, stiffness, function, and spatiotemporal gait variables in subjects with bilateral knee osteoarthritis (OA).Methods: Subjects with knee OA (Grades 1-3) were evaluated and randomized into four groups: Control Group (CG), untreated; Laser Group (LG), treated with laser at 808 nm, 5.6 J; Exercise Group (EG), treated with exercise; and Laser + Exercise Group (LEG), treated with laser and exercises. The treatment was carried out twice a week for 2 months. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire was applied for evaluation and reevaluation; evaluation of spatiotemporal gait variables was performed using GAITRite equipment.Results: The EG showed significant improvement in pain (p = 0.006) and function (p = 0.01) according to WOMAC. Regarding gait variables, in intergroup analysis after 8 weeks all groups receiving intervention showed a significant increase in gait speed: LG versus CG (p = 0.03); EG versus CG (p = 0.04) and LEG versus CG (p = 0.005). Only the group treated with laser + exercise showed a significant increase (p = 0.009) in the cadence and duration of single right limb support (p = 0.04), and only the groups treated with exercise and laser + exercise showed significant decreases in the duration of right limb support (p = 0.035 and p = 0.003, respectively), compared to the CG.Conclusions: The group treated only with exercise showed improvement in WOMAC questionnaire scores. Regarding the gait variables, all groups undergoing the interventions showed increases in the gait speed compared to the CG. The laser and exercise combination therapy provided the best results for the other gait variables (cadence and duration of right limb support and duration of single right limb support).Implications for rehabilitationThere are differences in gait patterns in patients with knee OA, including decreased gait speed, cadence, and step length.The results shown in the present study provide additional information about the physical therapy approaches that should be chosen during clinical practical to improve gait performance in individuals with knee osteoarthritis.The improvement in gait performance is a relevant issue due to the fact that is associated to physical independence and better quality of life.

Gait and functional status analysis before and after total knee arthroplasty

BACKGROUND

Among the procedures for severe gonarthrosis, total knee arthroplasty (TKA) is considered a successful method patient satisfaction and functional improvement; however, TKA is commonly associated with incompletely recovered gait function. The aim of this study was to evaluate the influence of TKA and physiotherapy programmes on gait features and patient-reported functional status and the relationship between them, leading to broader knowledge of the origins of long-term gait disturbances.

METHODS

Walking speed, step length and single support time were analysed by GAITRite system in 60 healthy controls and 21 TKA patients analysed at four time points: one day before and five days after surgery and before and after a three-week rehabilitation (12 and 15 weeks after surgery). Functional status was assessed using the Western Ontario and McMaster Osteoarthritis Index (WOMAC).

RESULTS

At all time points, the TKA subjects walked significantly slower than the controls, but walking speed continuously increased after surgery. Gait asymmetries were observed in single support time (before surgery) and step length (after surgery). Partial restoration of gait function was observed 12 weeks after surgery and completion of the rehabilitation programme. An indirect correlation between gait velocity and function WOMAC subscores was found.

CONCLUSIONS

Patients after TKA were characterised by significant improvements in self-reported functionality and progressive reduction of gait abnormalities, probably related to pain reduction. However, at 15 weeks after surgery, patients exhibited step length asymmetry, which could be considered as an effect of habits of three-point crutch gait in the early postoperative period.

Long-term evaluation of osteoarthritis sheep knee, treated with TGF-β3 and BMP-6 induced multipotent stem cells

BACKGROUND

Hyaline articular cartilage, which protects the bones of diarthrodial joints from forces associated with load bearing, frictions, and impacts has very limited capacities for self-repair. Over the years, the trend of treatments has shifted to regenerations and researchers have been on the quest for a lasting regeneration. We evaluated the treatment of osteoarthritis by chondrogenically induced ADSCs and BMSCs for a long time functional recovery.

METHODS

Osteoarthritis was induced at the right knee of sheep by complete resection of ACL and medial meniscus. Stem cells from sheep were induced to chondrogenic lineage. Test sheep received 5 mls single doses of 2 × 10⁷ autologous PKH26-labelled ADSCs or BMSCs, while controls received basal medium. Functional recovery of the knees was evaluated via electromyography.

RESULTS

Induced ADSCs had 625, 255, 393, 908, 409, 157 and 1062 folds increases of collagen I, collagen II, aggrecan, SOX9, cartilage oligomeric protein, chondroadherin and fibromodullin compare to uninduced cells, while BMSCs had 702, 657, 321, 276, 337, 233 and 1163 respectively; p = .001. Immunocytochemistry was positive for these chondrogenic markers. 12 months post-treatment, controls scored 4 in most regions using ICRS, while the treated had 8; P = .001. Regenerated cartilages were positive to PKH26 and demonstrated the presence of condensing cartilages on haematoxylin and eosin; and Safranin O. OA degenerations caused significant amplitude shift from right to left hind limb. After treatments, controls persisted with significant decreases; while treated samples regained balance.

CONCLUSIONS

Both ADSCs and BMSCs had increased chondrogenic gene expressions using TGF-β3 and BMP-6. The treated knees had improved cartilage scores; PKH26 can provide elongated tracking, while EMG results revealed improved joint recoveries. These could be suitable therapies for osteoarthritis.

A Comparison of Walking Gait Following Mechanical and Kinematic Alignment in Total Knee Joint Replacement

BACKGROUND

Although previous studies have compared radiological, pain, and function scores in kinematically aligned (KA) and mechanically aligned (MA) total knee arthroplasty (TKA), no previous studies have undertaken a three-dimensional (3D) gait analysis in these groups. This study compared kinematic and kinetic variables recorded during level walking in patients at least 2 years post-surgery who underwent an MA or KA procedure.

METHODS

Utilizing a 9-camera motion analysis system, gait analysis was undertaken on 29 patients (MA = 15, KA = 14). A 9-camera motion analysis system was used to collect 3D kinematic data of the involved and uninvolved limbs during walking at a self-selected speed. Additionally, 3D ground reaction forces and moments during the stance phase were recorded, and an inverse dynamics approach was utilized to analyze these data.

RESULTS

There were no significant differences in spatial-temporal variables between MA and KA groups (P > .05). Local minima and maxima for knee joint angles were not significantly different (P > .05) across involved and uninvolved legs and MA/KA groups in any of the 3 planes of motion. Principal component analysis revealed a significant difference (P < .05) in the transverse plane moment in late stance. No other significant differences were observed for knee, hip, or ankle joint moments.

CONCLUSION

Differences in gait parameters across the KA and MA groups at 2 years post-surgery were insufficient to support either one of the operative procedures over the other.

Influence of Body Mass Index on Sagittal Knee Range of Motion and Gait Speed Recovery 1-Year After Total Knee Arthroplasty

BACKGROUND

The purpose of this prospective study was to investigate the influence of body mass index (BMI) on gait parameters preoperatively and 1 year after total knee arthroplasty (TKA).

METHODS

Seventy-nine patients were evaluated before and 1 year after TKA using clinical gait analysis. The gait velocity, the knee range of motion (ROM) during gait, their gains (difference between baseline and 1 year after TKA), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), quality of life, and patient satisfaction were assessed. Nonobese (BMI <30 kg/m²) and obese patients (BMI ≥30 kg/m²) were compared. Healthy controls were also assessed. Univariate and multivariate linear regression analyses were used to assess the association between gait speed and ROM gains. Adjustment was performed for gender, age, and WOMAC pain improvement.

RESULTS

At baseline, gait velocity and knee ROM were significantly lower in obese compared with those in the nonobese patients (0.99 ± 0.27 m/s vs 1.11 ± 0.18 m/s; effect size, 0.53; P = .021; and ROM, 41.33° ± 9.6° vs 46.05° ± 8.39°; effect size, 0.52; P = .022). Univariate and multivariate linear regressions did not show any significant relation between gait speed gain or knee ROM gain and BMI. At baseline, obese patients were more symptomatic than nonobese (WOMAC pain: 36.1 ± 14.0 vs 50.4 ± 16.9; effect size, 0.9; P < .001), and their improvement was significantly higher (WOMAC pain gain, 44.5 vs 32.3; effect size, 0.59; P = .011).

CONCLUSION

These findings show that all patients improved biomechanically and clinically, regardless of their BMI.

Ankle strength impairments associated with knee osteoarthritis

BACKGROUND

Knee Osteoarthritis seems to negatively impact ankle biomechanics. However, the effect of knee osteoarthritis on ankle muscle strength has not been clearly established. This study aimed to evaluate the ankle strength of the plantar flexors and dorsiflexors of patients with knee osteoarthritis in different degrees of severity.

METHODS

Thirty-seven patients with knee osteoarthritis and 15 controls, subjected to clinical and radiographic analysis, were divided into three groups: control, mild, and moderate knee osteoarthritis. Participants answered a self-reported questionnaire and accomplished a muscle torque assessment of the ankle using the Biodex dynamometer in isometric, concentric and eccentric modes.

FINDINGS

The mild osteoarthritis group (peak torque=26.85(SD 3.58)) was significantly weaker than the control (peak torque=41.75(SD 4.42)) in concentric plantar flexion (P<0.05). The control and mild osteoarthritis groups were not significantly different from the moderate osteoarthritis group (peak torque=36.12(SD 4.61)) in concentric plantar flexion. There were no significant differences for dorsiflexion among the groups; however the control and moderate osteoarthritis groups presented large and medium standardized mean differences. The mild osteoarthritis group was significantly lower than the control and moderate osteoarthritis groups in the concentric plantar flexion by concentric dorsiflexion torque ratio.

INTERPRETATION

Ankle function exhibited impairments in patients with knee osteoarthritis, especially in the plantar flexion torque, in which the mild osteoarthritis group was weaker than the control. Interestingly, patients with moderate knee osteoarthritis showed results similar to the control group in plantar flexion torque. The results raise the possibility of a compensatory mechanism of the plantar flexors developed by patients in more advanced degrees to balance other muscle failures.

Knee Kinematic and Clinical Outcomes Evolution Before, 3 Months, and 1 Year After Total Knee Arthroplasty

BACKGROUND

The aim of this study was to describe the evolution of kinematic and clinical outcomes of a large patient cohort with knee osteoarthritis from before surgery (V1) to 3 months (V2) and 1 year (V3) after a total knee arthroplasty (TKA).

METHODS

The patients were evaluated at each visit (118 patients at V1, 93 patients at V2, and 79 patients at V3) during a clinical gait analysis and were compared with a matched control group of healthy adults (CG). The kinematic parameters, the Western Ontario and MacMaster Osteoarthritis Index (WOMAC), quality of life, and patient satisfaction were assessed. Gait velocity and knee range of motion (ROM) as well as clinical parameters were compared at each visit with CG was based on the unpaired samples t-test. To determine changes in the data at baseline, 3 months, and 1 year after surgery in the patient groups, repeated-measure analysis of variance was conducted (P < .05). Pearson correlation was used to examine relationships between clinical and biomechanical outcomes.

RESULTS

One year after TKA (V3) compared to V1 and V2, the ROM of the operated knee during gait was significantly improved (V1: 44.2 ± 8.8° vs V3: 47.5 ± 7.1°, P < .001, and V2: 42.2 ± 9.3° vs V3: 47.5 ± 7.1°, P = .001), as was the gait velocity (V1: 1.0 ± 0.2 and V2: 1.1 ± 0.2 m/s vs V3: 1.3 ± 0.2 m/s, P < .001). The WOMAC and knee pain were significantly better 1 year after TKA. No strong relationships have been found between clinical parameters and knee kinematics.

CONCLUSION

This study showed that 1 year after TKA, patients exhibited improved gait velocity and ROM and experienced a significant decrease in the level of pain and an increased clinical score (although different from CG).

Biomechanical deficits in patients at 3 months following total knee arthroplasty

OBJECTIVES

This study aimed to evaluate functional biomechanics in patients who undergo total knee arthroplasty (TKA).

METHODS

Lower limb joint kinematics and kinetics were evaluated in 25 TKA patients at 3 months following TKA and 25 age-matched controls after 12 months following TKA. Participants were evaluated in a gait laboratory, with self-selected gait speed.

RESULTS

Experimental group walked significantly slower (p < 0.01), using a shorter stride length (p < 0.01), compared to those for the controls. The experimental group exhibited significantly greater knee motion, lower knee extension moment (p < 0.01), and lower peak power generation (p < 0.01) compared to those for the control group. Additionally, the TKA group showed significantly smaller peak ankle motion (p < 0.01), lower ankle dorsiflexion moments (p < 0.05), and ankle power generation (p < 0.01) compared to those for the control group.

DISCUSSION

These biomechanical properties of gait in the experimental group may be a compensatory response to lesser recovered knee function to allow sufficient power generation for propulsion. Therefore, rehabilitative strategies at 3 months following TKA are needed to improve not only knee function but also hip and ankle function after TKA.

Knee Extensor Strength and Gait Characteristics After Minimally Invasive Unicondylar Knee Arthroplasty vs Minimally Invasive Total Knee Arthroplasty: A Nonrandomized Controlled Trial

BACKGROUND

In light of the existing lack of evidence, it was the aim of this study to compare gait characteristics and knee extensor strength after medial unicondylar knee arthroplasty (MUKA) with those after total knee arthroplasty (TKA), given the same standardized minimally invasive surgery (MIS) approach in both groups.

METHODS

Patients scheduled for MIS-MUKA or MIS-TKA as part of clinical routine were invited to participate. A posterior cruciate ligament-retaining total knee design was used for all MIS-TKA. A 3-dimensional gait analysis was performed preoperatively with a VICON system and at 8 weeks postoperative to determine temporospatial parameters, ground reaction forces, joint angles, and joint moments. At the same 2 times, isokinetic tests were performed to obtain peak values of knee extensor torque. A multivariate analysis of variance was conducted and included the main effects time (before and after surgery) and surgical group and the group-by-time interaction effect.

RESULTS

Fifteen MIS-MUKA patients and 17 MIS-TKA patients were eligible for the final analysis. The groups showed no differences regarding age, body mass index, sex, side treated, or stage of osteoarthritis. We determined neither intergroup differences nor time × group interactions for peak knee extensor torque or any gait parameters (temporospatial, ground reaction forces, joint angles, and joint moments).

CONCLUSION

It is concluded that MUKA is not superior to TKA with regard to knee extensor strength or 3-dimensional gait characteristics at 8 weeks after operation. As gait characteristics and knee extensor strength are only 2 of the various potential outcome parameters (knee scores, activity scores…) and quadriceps strength might take a longer time to recover, our findings should be interpreted with caution.

Clinical and Biomechanical Evaluations of Staged Bilateral Total Knee Arthroplasty Patients with Two Different Implant Designs

BACKGROUND

Various implants of total knee arthroplasty (TKA) are used in clinical practice and each presents specific design characteristics. No implant managed this day to reproduce perfectly the biomechanics of the natural knee during gait.

OBJECTIVES

We therefore asked whether (1) differences in tridimensional (3D) kinematic data during gait could be observed in two different designs of TKA on the same patients, (2) if those gait kinematic data are comparable with those of asymptomatic knees and (3) if difference in clinical subjective scores can be observed between the two TKA designs on the same patient.

METHODS

We performed knee kinematic analysis on 15 patients (30 TKAs) with two different TKA implant designs (Nexgen, Zimmer and Triathlon, Stryker) on each knee and on 25 asymptomatic subjects (35 knees). Clinical evaluation included range of motion, weight bearing radiographs, questionnaire of joint perception, KOOS, WOMAC and SF-12.

RESULTS

Comparison between TKAs and asymptomatic knees revealed that asymptomatic knees had significantly less knee flexion at initial contact (p < 0.04) and more flexion for most of the swing phase (p between 0.004 and 0.04). Asymptomatic knees also had less varus at loading response, during stance phase and during most of the swing phase (p between 0.001 - 0.05). Transverse plane analysis showed a tendency for asymptomatic knees to be more in internal rotation during stance phase (p 0.02 - 0.04). Comparing both TKA designs, Nexgen(TM) implant had significantly more flexion at the end of swing phase (p = 0.04) compared to knees with the Triathlon(TM) implant. In frontal plane, from initial contact to maximum mid stance angle and between the mean mid stance angle and initial contact Nexgen(TM) TKA had significantly more adduction (varus, p =0.02 - 0.03). Clinical scores of both TKAs did not have significant difference.

CONCLUSIONS

TKA with the tested implants did not reproduce natural knee kinematics during gait. In our cohort of patients, TKA implant design translated in limited kinematics differences during gait and on clinical results.

Prediction of medial and lateral contact force of the knee joint during normal and turning gait after total knee replacement

The computational modeling approach has commonly been used to predict knee joint contact forces, muscle forces, and ligament loads during activities of daily living. Knowledge of these forces has several potential applications, for example, within design of equipment to protect the knee joint from injury and to plan adequate rehabilitation protocols, although clinical applications of computational models are still evolving and one of the limiting factors is model validation. The objective of this study was to extend previous modeling technique and to improve the validity of the model prediction using publicly available data set of the fifth "Grand Challenge Competition to Predict In Vivo Knee Loads." A two-stage modeling approach, which combines conventional inverse dynamic analysis (the first stage) with a multi-body subject-specific lower limb model (the second stage), was used to calculate medial and lateral compartment contact forces. The validation was performed by direct comparison of model predictions and experimental measurement of medial and lateral compartment contact forces during normal and turning gait. The model predictions of both medial and lateral contact forces showed strong correlations with experimental measurements in normal gait (r = 0.75 and 0.71) and in turning gait trials (r = 0.86 and 0.72), even though the current technique over-estimated medial compartment contact forces in swing phase. The correlation coefficient, Sprague and Geers metrics, and root mean squared error indicated that the lateral contact forces were predicted better than medial contact forces in comparison with the experimental measurements during both normal and turning gait trials.

A multiple regression normalization approach to evaluation of gait in total knee arthroplasty patients

BACKGROUND

Gait features characteristic of a cohort may be difficult to evaluate due to differences in subjects' demographic factors and walking speed. The aim of this study was to employ a multiple regression normalization method that accounts for subject age, height, body mass, gender, and self-selected walking speed in the evaluation of gait in unilateral total knee arthroplasty patients.

METHODS

Three-dimensional gait analysis was performed on 45 total knee arthroplasty patients and 31 aged-matched controls walking at their self-selected speed. Gait data peaks including joint angles, ground reaction forces, net joint moments, and net joint powers were normalized using subject body mass, standard dimensionless equations, and a multiple regression approach that modeled subject age, height, body mass, gender, and self-selected walking speed.

FINDINGS

Normalizing gait data using subject body mass, dimensionless equations, and multiple regression approach resulted in a significantly lower knee adduction moment and knee extensor power in total knee arthroplasty patients compared to controls (p<0.05). In contrast to normalization using body mass and dimensionless equations, multiple regression normalization greatly reduced variance in gait data by minimizing correlations with subject demographic factors and walking speed, resulting in significantly higher peak hip extension angles and peak hip flexion powers in total knee arthroplasty patients (p<0.05).

INTERPRETATION

Total knee arthroplasty patients generate greater hip extension angles and hip flexor power and have a lower knee adduction moment than healthy controls. This gait pattern may be a strategy to reduce muscle and joint loading at the knee.

Effect of component mal-rotation on knee loading in total knee arthroplasty using multi-body dynamics modeling under a simulated walking gait

Mal-rotation of the components in total knee arthorplasty (TKA) is a major cause of postoperative complications, with an increased propensity for implant loosening or wear leading to revision. A musculoskeletal multi-body dynamics model was used to perform a parametric study of the effects of the rotational mal-alignments in TKA on the knee loading under a simulated walking gait. The knee contact forces were found to be more sensitive to variations in the varus-valgus rotation of both the tibial and the femoral components and the internal-external rotation of the femoral component in TKA. The varus-valgus mal-rotation of the tibial or femoral component and the internal-external mal-rotation of the femoral component with a 5° variation were found to affect the peak medial contact force by 17.8-53.1%, the peak lateral contact force by 35.0-88.4% and the peak total contact force by 5.2-18.7%. Our findings support the clinical observations that a greater than 3° internal mal-rotation of the femoral component may lead to unsatisfactory pain levels and a greater than 3° varus mal-rotation of the tibial component may lead to medial bone collapse. These findings determined the quantitative effects of the mal-rotation of the components in TKA on the contact load. The effect of such mal-rotation of the components of TKA on the kinematics would be further addressed in future studies.

Anatomical calibration for wearable motion capture systems: Video calibrated anatomical system technique

Inertial sensors are becoming widely used for the assessment of human movement in both clinical and research applications, thanks to their usability out of the laboratory. This work aims to propose a method for calibrating anatomical landmark position in the wearable sensor reference frame with an ease to use, portable and low cost device. An off-the-shelf camera, a stick and a pattern, attached to the inertial sensor, compose the device. The proposed technique is referred to as video Calibrated Anatomical System Technique (vCAST). The absolute orientation of a synthetic femur was tracked both using the vCAST together with an inertial sensor and using stereo-photogrammetry as reference. Anatomical landmark calibration showed mean absolute error of 0.6±0.5 mm: these errors are smaller than those affecting the in-vivo identification of anatomical landmarks. The roll, pitch and yaw anatomical frame orientations showed root mean square errors close to the accuracy limit of the wearable sensor used (1°), highlighting the reliability of the proposed technique. In conclusion, the present paper proposes and preliminarily verifies the performance of a method (vCAST) for calibrating anatomical landmark position in the wearable sensor reference frame: the technique is low time consuming, highly portable, easy to implement and usable outside laboratory.

Motion analysis of patients after knee arthroplasty during activities of daily living--a systematic review

BACKGROUND

Motion analysis with optoelectronic systems is a frequently used method to analyze the patient's gait as well as further relevant activities of daily living before and after knee arthroplasty. The aim of this systematic review was to identify the investigated activities of daily living and to show an extensive presentation of gait analysis studies with patients after knee arthroplasty surgery.

METHODS

The articles were searched in electronic databases: MEDPILOT, EMBASE. To identify articles that potentially met the inclusion criteria the titles and abstracts were screened. The level of evidence was analyzed for the included articles.

RESULTS

Overall 3989 abstracts were reviewed and 87 full text articles were included. Ten activities of daily living were identified. Level walking was the most frequently investigated activity (78.2%). In 94.6% the sagittal plane kinematics were analyzed and 5.3% presented the results in all three planes. Knee adduction moments were determined in 33.3% of the included articles. At least two joints were investigated in 40.2%, including the impaired knee and further body parts (ankle, hip, pelvis, trunk). Unicondylar knee arthroplasty was addressed in 14.1%.

CONCLUSIONS

Besides level walking, it is necessary to examine physical more demanding activities of daily living to detect potential kinematic and kinetic abnormalities. Further research should imply the evaluation of sagittal, frontal and transverse plane joint and muscle function based on accurate inverse-dynamic techniques. More motion analysis studies are necessary that address unicondylar knee arthroplasty in comparison to total knee arthroplasty and healthy controls.

Evolution of knee kinematics three months after total knee replacement

In patients with debilitating knee osteoarthritis, total knee replacement is the most common surgical procedure. Numerous studies have demonstrated that knee kinematics one year after total knee replacement are still altered compared to the healthy joint. However, little is known regarding impairments and functional limitations of patients several months after total knee replacement. The aim of this study was to describe the evolution of the knee gait kinematic in patients with knee osteoarthritis before and three months after a total knee replacement. Ninety patients who were to undergo total knee replacement were included in this study. Twenty-three subjects were recruited as the control group. Three-dimensional gait analysis was performed before and three months after surgery. The spatio-temporal parameters and three-dimensional knee kinematics for the operated limb were evaluated during a comfortable gait and compared between groups (the before and after surgery groups and the control group). Three months after surgery, patients always walk with a slower gait velocity and lower knee flexion-extension movements compared to the control group. However, a degree of progress was observed in term of the stride and step length, gait velocity and knee alignment in the coronal plane. Our results suggest that the disability is still significant for most patients three months after total knee replacement. A better understand of the impairments and functional limitations following surgery would help clinicians design rehabilitation programs. Moreover, patients should be informed that rehabilitation after total knee replacement is a long process.

Mini-midvastus total knee arthroplasty does not result in superior gait pattern

PURPOSE

Previous studies dealing with gait after minimally invasive surgery (MIS) total knee arthroplasty (TKA) are rare and insufficient. It was the purpose of the study to determine in a prospective, comparative setting whether MIS influences the outcome of TKA in terms of typical 3D gait parameters.

METHODS

Patients scheduled for TKA or MIS TKA were invited to participate. MIS TKA was defined as TKA with shorter skin incision, mini-midvastus arthrotomy, special instruments, and avoidance of tibiofemoral dislocation and patella eversion. All other intra- and perioperative aspects were identical for both groups. A 3D gait analysis was performed with a VICON system 1 month preoperative and 8 weeks post-operative. A multivariate analysis of variance was conducted including the main effects time (pre- and post-surgery) and surgical group and the group-by-time interaction effect.

RESULTS

Seventeen MIS TKA patients and 20 TKA patients were eligible for the final analysis. We determined neither inter-group differences nor time × group interactions for any gait variables (temporospatial, ground reaction forces, joint angles and joint moments)—except for the varus-valgus knee kinematics. In pre- to post-operative comparison, the maximum valgus sway increased in the MIS group, whereas it decreased in the conventional group (p = 0.001).

CONCLUSION

From our findings, it was concluded that MIS TKA does not result in a superior walking pattern 8 weeks post-operative. Because we previously also observed mini-midvastus MIS TKA to have equal or slightly inferior results with regard to knee scores, knee torque, radiographic outcome and tourniquet/operating time, we discontinued the procedure.

LEVEL OF EVIDENCE

Prospective comparative study, Therapy, Level II.

Longitudinal changes in knee kinematics and moments following knee arthroplasty: a systematic review

BACKGROUND

Knee arthroplasty (KA) is recognized as an effective treatment of knee joint osteoarthritis and up to 90% of patients experience substantial pain relief. There has been no systematic review synthesizing the longitudinal changes in gait following KA. The aims of this systematic review were to determine the effects of KA on (i) frontal plane and (ii) sagittal plane kinematic and kinetic parameters during the stance phase of gait.

METHODS

MEDLINE (PubMed), CINAHL, SPORTdiscus (EBSCO), and Cochrane Library (Wiley) were searched until April 10th, 2014. 1,765 articles were identified, of which 19 studies describing 3-dimensional gait analysis pre- and post-KA were included. Study quality was evaluated by two reviewers independently using the Downs and Black checklist.

FINDINGS

Following KA, in the frontal plane, the maximum knee adduction angle and external knee adduction moment (KAM) tended to decrease. In the sagittal plane, findings suggest that the maximum knee flexion moment is increased. From the ten studies that included a healthy reference group, it was unclear whether gait variables returned to normal following KA.

INTERPRETATION

Overall, it appears that KA results in a decreased peak KAM and maximum knee adduction angles, an increased peak knee flexion moment and inconsistent changes in the peak knee flexion angle. Knowledge gaps remain due to methodological inconsistencies across studies, limited statistical analysis, and largely heterogeneous sample populations. More research is needed to determine whether KA restores gait patterns to normal, or if additional rehabilitation may be needed to optimize gait following surgery for osteoarthritis.