Knee biomechanics early after knee replacement surgery predict abnormal gait patterns 12 months postoperatively

The role of commercially available smartphone apps and wearable devices in monitoring patients after total knee arthroplasty: a systematic review

Purpose

Commercially available smartphone apps and wearable devices have proven valuable in a variety of clinical settings, yet their utility in measuring physical activity and monitoring patient status following total knee arthroplasty (TKA) remains unclear.

Methods

A systematic review was performed to assess the evidence supporting the use of smartphone apps and wearable devices to assist rehabilitation interventions following TKA. A search was conducted in the PubMed, Cochrane, Medline, and Web of Science databases in September 2021.

Results

One hundred and seventy-six studies were retrieved, of which 15 met inclusion criteria, including 6 randomized control trials. Four of these studies utilized smartphone apps, seven utilized wearable devices, and four utilized a combination of both. A total of 1607 TKA patients participated in the included studies. For primary outcomes, three reported on device accuracy, three on recovery prediction, two on functional recovery, two on physical activity promotion, two on patient compliance, two on pain control, and one on healthcare utilization.

Conclusion

Commercially available smartphone apps and wearable devices were shown to capably monitor physical activity and improve patient engagement following TKA, making them potentially viable adjuncts or replacements to traditional rehabilitation programs. Components of interventions such as step goals, app-based patient engagement platforms, and patient-specific benchmarks for recovery may improve effectiveness. However, future research should focus on the economics of implementation, long-term outcomes, and optimization of compliance and accuracy when using these devices.

Can the Output of a Learned Classification Model Monitor a Person's Functional Recovery Status Post-Total Knee Arthroplasty?

Osteoarthritis is a common musculoskeletal disorder. Classification models can discriminate an osteoarthritic gait pattern from that of control subjects. However, whether the output of learned models (probability of belonging to a class) is usable for monitoring a person’s functional recovery status post-total knee arthroplasty (TKA) is largely unexplored. The research question is two-fold: (I) Can a learned classification model’s output be used to monitor a person’s recovery status post-TKA? (II) Is the output related to patient-reported functioning? We constructed a logistic regression model based on (1) pre-operative IMU-data of level walking, ascending, and descending stairs and (2) 6-week post-operative data of walking, ascending-, and descending stairs. Trained models were deployed on subjects at three, six, and 12 months post-TKA. Patient-reported functioning was assessed by the KOOS-ADL section. We found that the model trained on 6-weeks post-TKA walking data showed a decrease in the probability of belonging to the TKA class over time, with moderate to strong correlations between the model’s output and patient-reported functioning. Thus, the LR-model’s output can be used as a screening tool to follow-up a person’s recovery status post-TKA. Person-specific relationships between the probabilities and patient-reported functioning show that the recovery process varies, favouring individual approaches in rehabilitation.

Movement Quality Parameters during Gait Assessed by a Single Accelerometer in Subjects with Osteoarthritis and Following Total Joint Arthroplasty

This study’s aim is threefold: (I) Evaluate movement quality parameters of gait in people with hip or knee osteoarthritis (OA) compared to asymptomatic controls from a single trunk-worn 3D accelerometer. (II) Evaluate the sensitivity of these parameters to capture changes at 6-weeks, 3-, 6-, and 12-months following total knee arthroplasty (TKA). (III) Investigate whether observed changes in movement quality from 6-weeks and 12-months post-TKA relates to changes in patient-reported outcome measures (PROMs). We invited 20 asymptomatic controls, 20 people with hip OA, 18 people pre- and post-TKA to our movement lap. They wore a single trunk-worn accelerometer and walked at a self-selected speed. Movement quality parameters (symmetry, complexity, smoothness, and dynamic stability) were calculated from the 3D acceleration signal. Between groups and between timepoints comparisons were made, and changes in movement quality were correlated with PROMs. We found significant differences in symmetry and stability in both OA groups. Post-TKA, most parameters reflected an initial decrease in movement quality at 6-weeks post-TKA, which mostly normalised 6-months post-TKA. Finally, improved movement quality relates to improvements in PROMs. Thus, a single accelerometer can characterise movement quality in both OA groups and post-TKA. The correlation shows the potential to monitor movement quality in a clinical setting to inform objective, data-driven personalised rehabilitation.

Are there functional biomechanical differences in robotic arm-assisted bi-unicompartmental knee arthroplasty compared with conventional total knee arthroplasty? A prospective, randomized controlled trial

AIMS

The aim of this study was to compare any differences in the primary outcome (biphasic flexion knee moment during gait) of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) at one year post-surgery.

METHODS

A total of 76 patients (34 bi-UKA and 42 TKA patients) were analyzed in a prospective, single-centre, randomized controlled trial. Flat ground shod gait analysis was performed preoperatively and one year postoperatively. Knee flexion moment was calculated from motion capture markers and force plates. The same setup determined proprioception outcomes during a joint position sense test and one-leg standing. Surgery allocation, surgeon, and secondary outcomes were analyzed for prediction of the primary outcome from a binary regression model.

RESULTS

Both interventions were shown to be effective treatment options, with no significant differences shown between interventions for the primary outcome of this study (18/35 (51.4%) biphasic TKA patients vs 20/31 (64.5%) biphasic bi-UKA patients; p = 0.558). All outcomes were compared to an age-matched, healthy cohort that outperformed both groups, indicating residual deficits exists following surgery. Logistic regression analysis of primary outcome with secondary outcomes indicated that the most significant predictor of postoperative biphasic knee moments was preoperative knee moment profile and trochlear degradation (Outerbridge) (R² = 0.381; p = 0.002, p = 0.046). A separate regression of alignment against primary outcome indicated significant bi-UKA femoral and tibial axial alignment (R² = 0.352; p = 0.029), and TKA femoral sagittal alignment (R² = 0.252; p = 0.016). The bi-UKA group showed a significant increased ability in the proprioceptive joint position test, but no difference was found in more dynamic testing of proprioception.

CONCLUSION

Robotic arm-assisted bi-UKA demonstrated equivalence to TKA in achieving a biphasic gait pattern after surgery for osteoarthritis of the knee. Both treatments are successful at improving gait, but both leave the patients with a functional limitation that is not present in healthy age-matched controls. Cite this article: Bone Joint J 2022;103-B(4):433-443.

Optimal designs and surgical technique for hip and knee joint replacement: The best is yet to come!

Over the last three decades, there have been significant advancements in knee and hip replacement technology. The implants and the surgical technology we now have to aid in their implantation are advancing and improving functional outcomes and survivorship. Despite these advancements, there are still issues with patient satisfaction, functional limitations, and early revisions due to instability and aseptic loosening. This article reviews the state of current technology in hip and knee replacement implant design and surgical technique, and reviews some of the current implant designs and surgical technologies that may be able to solve some of the most common issues in the knee and hip replacement surgery.

Importance of knee flexion range of motion during the acute phase after total knee arthroplasty

BACKGROUND

We investigate the association with knee flexion range of motion (ROM) during the acute phases and that at 12 months after total knee arthroplasty (TKA). We also clarified the cut-off ROM during the acute phases in predicting the goal of knee flexion ROM at 12 months.

METHODS

In this retrospective study, 193 patients with knee osteoarthritis (female:144 patients, age:73.2 ± 7.7 years) who underwent unilateral TKA at an orthopedic clinic were recruited. They underwent assessments of knee flexion ROM at 5 days, 1 month, and 12 months after TKA. The goal of knee flexion ROM at 12 months after TKA was set at 120°. Single and logistic-regression analyses were performed with the dependent variables including the outcome of the goal of knee flexion ROM at 12 months, and the independent variables included knee flexion ROM at 5 days and 1 month, separately. We calculated the cut-off ROM at 5 days and 1 month for predicting the goal of knee flexion ROM at 12 months with receiver operating curve analysis.

RESULTS

Knee flexion ROM at 5 days and 1 month were significantly associated with the goal of that at 12 months (p < 0.01). The cut-off ROM were 85° at 5 days and 105° at 1 month separately.

CONCLUSIONS

Our results suggest the importance of early improvement in knee flexion ROM after TKA, and that at 1 month postoperatively indicates the likelihood of achievement of the goal of knee flexion ROM at 12 months after TKA.

Knee joint biomechanics of patients with unilateral total knee arthroplasty during stationary cycling

Stationary cycling is typically recommended following total knee arthroplasty (TKA) operations. However, knee joint biomechanics during cycling remains mostly unknown for TKA patients. Biomechanical differences between the replaced and non-replaced limb may inform applications of cycling in TKA rehabilitation. The purpose of this study was to examine the knee joint biomechanics of TKA patients during stationary cycling. Fifteen TKA participants cycled at 80 revolutions per minute and workrates of 80 W and 100 W while kinematics (240 Hz) and pedal reaction forces using a pair of instrumented pedals (1200 Hz) were collected. A 2x2 (limb × workrate) repeated measures ANOVA was run with an alpha of 0.05. Peak knee extension moment (KEM, p = 0.034) and vertical pedal reaction force (p = 0.038) were significantly reduced in the replaced limbs compared to non-replaced limbs by 21.3% and 5.3%, respectively. Peak KEM did not change for TKA patients with the increased workrate (p = 0.750). However, both peak hip extension moment (p = 0.009) and ankle plantarflexion moment (p = 0.017) increased due to increased workrate. Patients following TKA showed similar decreases in peak KEM and vertical pedal reaction force in their replaced compared to non-replaced limbs, as previously seen in gait. Patients of TKA may rely on their hip and ankle extensors to increases in workrate. Increasing intensity by 20 W did not exacerbate any inter-limb differences for peak KEM and vertical PRF.

Deep Learning in Gait Parameter Prediction for OA and TKA Patients Wearing IMU Sensors

Quantitative assessments of patient movement quality in osteoarthritis (OA), specifically spatiotemporal gait parameters (STGPs), can provide in-depth insight into gait patterns, activity types, and changes in mobility after total knee arthroplasty (TKA). A study was conducted to benchmark the ability of multiple deep neural network (DNN) architectures to predict 12 STGPs from inertial measurement unit (IMU) data and to identify an optimal sensor combination, which has yet to be studied for OA and TKA subjects. DNNs were trained using movement data from 29 subjects, walking at slow, normal, and fast paces and evaluated with cross-fold validation over the subjects. Optimal sensor locations were determined by comparing prediction accuracy with 15 IMU configurations (pelvis, thigh, shank, and feet). Percent error across the 12 STGPs ranged from 2.1% (stride time) to 73.7% (toe-out angle) and overall was more accurate in temporal parameters than spatial parameters. The most and least accurate sensor combinations were feet-thighs and singular pelvis, respectively. DNNs showed promising results in predicting STGPs for OA and TKA subjects based on signals from IMU sensors and overcomes the dependency on sensor locations that can hinder the design of patient monitoring systems for clinical application.

New materials for hip and knee joint replacement: What's hip and what's in kneed?

Over the last three decades there have been significant advancements in the knee and hip replacement technology that has been driven by an issue in the past concerning adverse local tissue reactions, aseptic and septic loosening. The implants and the materials we utilize have improved over the last two decades and in knee and hip replacement there has been a decrease in the failures attributed to wear and osteolysis. Despite these advancements there are still issues with patient satisfaction and early revisions due to septic and aseptic loosening in knee replacement patients. This article reviews the state of current implant material technology in hip and knee replacement surgery, discusses some of the unmet needs we have in biomaterials, and reviews some of the current biomaterials and technology that may be able to solve the most common issues in the knee and hip replacement surgery.

Movement pattern biofeedback training after total knee arthroplasty: Randomized clinical trial protocol

INTRODUCTION

Total knee arthroplasty (TKA) reduces joint symptoms, but habitual movement compensations persist years after surgery. Preliminary research on movement training interventions have signaled initial efficacy for remediating movement compensations and restoring knee joint loading symmetry during dynamic functional tasks after TKA. The purpose of this clinical trial is to determine if physical rehabilitation that includes movement training restores healthy movement patterns after TKA and reduces the risk of osteoarthritis (OA) progression in the contralateral knee.

METHODS/DESIGN

150 participants will be enrolled into this randomized controlled trial. Participants will be randomly allocated to one of two dose-equivalent treatment groups: standard rehabilitation plus movement training (MOVE) or standard rehabilitation without movement training (CONTROL). Movement training will promote between-limb symmetry and surgical knee loading during activity-based exercises. Movement training strategies will include real-time biofeedback using in-shoe pressure sensors and verbal, visual, and tactile cues from the physical therapist. The primary outcome will be change in peak knee extension moment in the surgical knee during walking, from before surgery to six months after surgery. Secondary outcomes will include lower extremity movement symmetry during functional tasks, physical function, quadriceps strength, range of motion, satisfaction, adherence, contralateral knee OA progression, and incidence of contralateral TKA.

DISCUSSION

This study will provide insights into the efficacy of movement training after unilateral TKA, along with mechanisms for optimizing long-term physical function and minimizing negative sequelae of compensatory movement patterns.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

A Biomechanical Foot-Worn Device Improves Total Knee Arthroplasty Outcomes

BACKGROUND

Biomechanics after total knee arthroplasty (TKA) often remain abnormal and may lead to prolonged postoperative recovery. The purpose of this study is to assess a biomechanical therapy after TKA.

METHODS

This is a randomized controlled trial of 50 patients after unilateral TKA. One group underwent a biomechanical therapy in which participants followed a walking protocol while wearing a foot-worn biomechanical device that modifies knee biomechanics and the control group followed a similar walking protocol while wearing a foot-worn sham device. All patients had standard physical therapy postoperatively as well. Patients were evaluated throughout the first postoperative year with clinical measures and gait analysis.

RESULTS

Improved outcomes were seen in the biomechanical therapy group compared to the control group in pain scores (88% vs 38%, P = .011), function (86% vs 21%, P = .001), knee scores (83% vs 38%, P = .001), and walking distance (109% vs 47%, P = .001) at 1 year. The therapy group showed healthier biomechanical gait patterns in both the sagittal and coronal planes at 1 year.

CONCLUSION

A postoperative biomechanical therapy improves outcomes following TKA and should be considered as an additional therapy postoperatively.

Joint loading and proximal tibia subchondral trabecular bone microarchitecture differ with walking gait patterns in end-stage knee osteoarthritis

OBJECTIVES

To (1) stratify patient subgroups according to their distinct walking gait patterns in end-stage knee osteoarthritis (OA); (2) compare measures of joint loading and proximal tibia subchondral trabecular bone (STB) microarchitecture among these gait subgroups.

DESIGN

Twenty-five knee OA patients undergoing total knee arthroplasty (TKA) had pre-operative gait analysis. Following surgery, excised tibial plateaus were micro-CT-scanned and STB microarchitecture analysed in four tibial condylar regions of interest. Peak knee moments were input to k-means cluster analysis, to identify subgroups with homogeneous gait patterns. Joint loading and STB microarchitecture parameters were compared among gait subgroups (Kruskal-Wallis, Bonferroni-corrected Mann-Whitney U tests).

RESULTS

Three gait subgroups were revealed: biphasics (n = 7), flexors (n = 9), counter-rotators (n = 9). Peak knee adduction moment (KAM) and KAM impulse were significantly higher (P < 0.05) in biphasics than in flexors and counter-rotators (KAM = -0.65, -0.40 and -0.21 Nm/kg, respectively), suggesting a higher medial-to-lateral tibiofemoral load ratio in biphasics. Interestingly, STB medial-to-lateral bone volume fraction (BV/TV) ratio was also significantly higher (more than double) in biphasics and flexors than in counter-rotators (2.24, 2.00 and 1.00, respectively), whereas in biphasics it was only 10% higher than in flexors and not significantly so.

CONCLUSIONS

Within the confines of the limited sample size, data suggests that different mechanisms between the biphasic and flexor gait subroups may generate comparable loads upon the tibial plateau and corresponding bony responses, despite significantly lower KAM indices in flexors. Hence, in flexor gait OA patients, conservative treatments designed to reduce KAM, may not be appropriate. Understanding joint loading among walking gait patterns and relationships to bone microarchitecture may aid at identifying/improving management of persons at risk for developing knee OA.

Clinical Evaluation and Gait Characteristics before and after Total Knee Arthroplasty Based on a Portable Gait Analyzer

OBJECTIVE

To evaluate the effects of surgery and rehabilitation on patients undergoing total knee arthroplasty (TKA).

METHODS

Twelve patients and 12 healthy controls were enrolled and their clinical scores evaluated by a doctor. Gait data, including walking velocity, stride length, single support time, foot fall and swing power, were collected using a portable gait analyzer from 12 patients before and 6 weeks and 6 months after surgery and from 12 healthy controls. The gait data and clinical scores at selected time points were compared and correlations between gait characteristics and clinical scores assessed.

RESULTS

Clinical knee and knee function scores increased significantly from before surgery to 6 weeks to 6 months after surgery (P < 0.001). The only significant differences identified were for single support time on the diseased side between before surgery and 6 months after surgery (P = 0.031) and for foot fall with the diseased side between 6 weeks and 6 months after surgery (P = 0.016). Foot fall and speed of the healthy or diseased sides were significantly different in patients at all time points from those of the healthy subjects (P < 0.05). Single support time on the diseased side was significantly different 6 months after surgery (P = 0.035) in patients than in healthy controls. Single support time on the healthy side before surgery was significantly different from that of healthy controls (P = 0.048) and 6 weeks after surgery (P = 0.042). Stride lengths differed significantly between patients and healthy subjects before surgery (healthy side: P = 0.007; diseased side: P = 0.008) and 6 weeks after surgery (healthy side: P = 0.001; diseased side: P = 0.001), but were not different at 6 months after surgery (healthy side: P = 0.088; diseased side: P = 0.077). The only significant correlations identified were between single support time with the diseased side of patients and their knee (r = 0.43, P = 0.032) and knee function scores (r = 0.493, P = 0.012).

CONCLUSIONS

A portable gait analyzer appears to be suitable for evaluating the effects of TKA. Single support time on the diseased side may be a sensitive quantitative index for determining the effect of TKA and rehabilitation.

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).

Predicting the location of the hip joint centres, impact of age group and sex

Clinical gait analysis incorporating three-dimensional motion analysis plays a key role in planning surgical treatments in people with gait disability. The position of the Hip Joint Centre (HJC) within the pelvis is thus critical to ensure accurate data interpretation. The position of the HJC is determined from regression equations based on anthropometric measurements derived from relatively small datasets. Current equations do not take sex or age into account, even though pelvis shape is known to differ between sex, and gait analysis is performed in populations with wide range of age. Three dimensional images of 157 deceased individuals (37 children, 120 skeletally matured) were collected with computed tomography. The location of the HJC within the pelvis was determined and regression equations to locate the HJC were developed using various anthropometrics predictors. We determined if accuracy improved when age and sex were introduced as variables. Statistical analysis did not support differentiating the equations according to sex. We found that age only modestly improved accuracy. We propose a range of new regression equations, derived from the largest dataset collected for this purpose to date.

Robotic Total Knee Arthroplasty: Surgical Assistant for a Customized Normal Kinematic Knee

Although current total knee arthroplasty (TKA) is considered a highly successful surgical procedure, patients undergoing TKA can still experience substantial functional impairment and increased revision rates as compared with those undergoing total hip arthroplasty. Robotic-assisted surgery has been available clinically for almost 15 years and was developed, in part, to address these concerns. Robotic-assisted surgery aims to improve TKA by enhancing the surgeon's ability to optimize soft tissue balancing, reproduce alignment, and restore normal knee kinematics. Current systems include a robotic arm with a variety of different navigation systems with active, semi-active, or passive control. Semi-active systems have become the dominant strategy, providing a haptic window through which the surgeon consistently prepares a TKA based on preoperative planning. A review of previous designs and clinical studies demonstrates that these robotic systems decrease variability and increase precision, primarily with the mechanical axis and restoration of the joint line. Future design objectives include precise planning and consistent intraoperative execution. Preoperative planning, intraoperative sensors, augmenting surgical instrumentation, and biomimetic surfaces will be used to re-create the 4-bar linkage system in the knee. Implants will be placed so that the knee functions with a medial pivot, lateral rollback, screw home mechanism, and patellar femoral tracking. Soft tissue balancing will become more than equalizing the flexion and extension gaps and will match the kinematics to a normal knee. Together, coupled with advanced knee designs, they may be the key to a patient stating, "My knee feels like my natural knee." [Orthopedics. 2016; 39(5):e822-e827.].

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.

Effect of Pedal Deformity on Gait in a Patient With Total Knee Arthroplasty

The authors present the case of an 81-year-old man who, despite an anatomically aligned total knee arthroplasty, continued to have knee pain. The patient's ipsilateral rigid flatfoot caused by an earlier partial pedal amputation resulted in a valgus moment during gait, thus creating clinical symptoms in the total knee arthroplasty. Because of the deformity and scarring within the flatfoot, this valgus deformity was corrected through a varus distal femoral osteotomy. The result was normalization of the mechanical axis of the lower limb and a pain-free total knee arthroplasty with an excellent clinical outcome. This case shows the importance of comprehensive lower-extremity clinical and radiographic examination as well as gait analysis to understand the biomechanical effect on total knee arthroplasty. Recognition of pedal deformities and lower limb malalignment is paramount for achieving optimal outcomes and long-term success of total knee arthroplasty. The authors show that a rigid or nonflexible pedal deformity can have negative biomechanical effects on total knee arthroplasty.

Gait changes after using a temporomandibular joint exerciser in patients who underwent lower limb joint surgery

[Purpose] The improvements in gait of the patients with lower limb disease who used a temporomandibular joint (TMJ) exerciser were verified. [Subjects and Methods] Eleven subjects were included. Their mean age was 53.2 years. The lower limb joint angles before and after using the TMJ exerciser were measured using a gait analyzer. Before the gait experiment, the TMJ exerciser setting process and one-leg stance balance test (OLST) were repeated until the balance maintenance time improved. [Results] Because of the OLST, the mean change in the body center point after the subjects used the exerciser improved from 5.76 mm to 4.20 mm. When the TMJ exerciser was used, the joint angle range of the subjects approached that of the normal individuals. [Conclusion] According to the gait experiments, the angles of the subjects' hips, knees, and ankle joints approached to those of the normal individuals after the subjects used the TMJ exerciser; however, the results did not completely match. The changes in the hip, knee, and ankle joint angles were statistically significant, which confirm the usefulness of the TMJ exerciser.

A real time biofeedback using Kinect and Wii to improve gait for post-total knee replacement rehabilitation: a case study report

PURPOSE

This study aimed to develop a low-cost real-time biofeedback system to assist with rehabilitation for patients following total knee replacement (TKR) and to assess its feasibility of use in a post-TKR patient case study design with a comparison group.

METHOD

The biofeedback system consisted of Microsoft Kinect(TM) and Nintendo Wii balance board with a dedicated software. A six-week inpatient rehabilitation program was augmented by biofeedback and tested in a single patient following TKR. Three patients underwent a six weeks standard rehabilitation with no biofeedback and served as a control group. Gait, function and pain were assessed and compared before and after the rehabilitation.

RESULTS

The biofeedback software incorporated real time visual feedback to correct limb alignment, movement pattern and weight distribution. Improvements in pain, function and quality of life were observed in both groups. The strong improvement in the knee moment pattern demonstrated in the case study indicates feasibility of the biofeedback-augmented intervention.

CONCLUSION

This novel biofeedback software has used simple commercially accessible equipment that can be feasibly incorporated to augment a post-TKR rehabilitation program. Our preliminary results indicate the potential of this biofeedback-assisted rehabilitation to improve knee function during gait. Research is required to test this hypothesis. Implications for Rehabilitation The real-time biofeedback system developed integrated custom-made software and simple low-cost commercially accessible equipment such as Kinect and Wii board to provide augmented information during rehabilitation following TKR. The software incorporated key rehabilitation principles and visual feedback to correct alignment of the lower legs, pelvic and trunk as well as providing feedback on limbs weight distribution. The case study patient demonstrated greater improvement in their knee function where a more normal biphasic knee moment was achieved following the six-week biofeedback intervention.

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.

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.

New approach for the rehabilitation of patients following total knee arthroplasty

PURPOSE

To investigate the effect of a biomechanical therapy on gait, function and clinical condition in patients following total knee arthroplasty (TKA).

METHODS

Seventeen TKA patients participated in the study. Patients received a biomechanical therapy AposTherapy). Patients underwent a gait test, clinical examination and an assessment of pain, function and quality of life (QOL). Patients were examined again at one, three and six month follow-ups.

RESULTS

A significant improvement over time was found in most gait measurements. Significant improvements were also found in pain, function and QOL.

CONCLUSIONS

The examined biomechanical therapy may help in the rehabilitation process following TKA.

Preoperative asymmetry in load distribution during quiet stance persists following total knee arthroplasty

PURPOSE

Preoperative function has been shown to persist posttotal knee arthroplasty. However, it remains unclear whether asymmetries are task specific. Therefore, we investigated postoperative asymmetries in loading during quiet stance and walking gait.

METHODS

Ten patients with end-stage knee osteoarthritis scheduled for total knee arthroplasty were studied at baseline (preoperative), 6-week, 3- and 6-month postoperative. Load distribution and balance were quantified during quiet stance. Furthermore, dynamic loading was quantified during walking gait. Patient satisfaction was assessed using the Knee Osteoarthritis and injury Outcome Score.

RESULTS

Preoperatively, load distribution was significantly different between limbs, with approximately 70% of the load through the contralateral or 'good' side. Asymmetries persisted and up to 6-month postoperative during quiet stance. No significant change was found in balance. During walking, preoperative loading asymmetry was present; however, no significant postoperative loading asymmetries were identified.

CONCLUSIONS

Total knee arthroplasty does not appear to significantly change load distribution or balance 6-month postoperative during quiet stance; however, during walking gait, symmetry appears to be restored. This could be potentially improved through enhanced rehabilitation.

LEVEL OF EVIDENCE

Therapeutic study, Level IV.

Abnormal axial rotations in TKA contribute to reduced weightbearing flexion

BACKGROUND

Previous in vivo fluoroscopy studies have documented that axial rotation for patients having a TKA was significantly less than those having a normal knee. In fact, many subjects having a TKA experience a reverse axial rotation pattern where the femur internally rotates with increasing flexion. However, no previous studies have been conducted to determine if this reverse axial rotation pattern affects TKA performance.

QUESTIONS/PURPOSES

The purposes of this study were: (1) Do normal and reverse axial rotation patterns of a TKA affect the maximum flexion angle postoperatively? (2) Does the axial rotation angle of the knee at maximum flexion during weightbearing impact the magnitude of the maximum flexion achieved in weightbearing?

METHODS

One hundred twenty patients having TKA, previously analyzed under in vivo conditions using fluoroscopy and a three-dimensional model-fitting software package, were further evaluated to determine if reverse axial rotation patterns limit weightbearing TKA flexion. In this retrospective cohort, we identified 58 patients who had a normal axial rotation pattern (greater than 15° normal rotation). Sixty-two patients experienced greater than 3° of reverse axial rotation, defined as internal rotation of the femur relative to the tibia.

RESULTS

Patients having a normal axial rotation achieved greater weightbearing knee flexion than those with reverse axial rotation (115° versus 109°, p = 0.02). Additionally, patients with greater than 3° of normal axial rotation at maximum flexion had more flexion than those with less than 3° of normal axial rotation at ending flexion (115° versus 107°, p < 0.001).

CONCLUSIONS

These findings show reverse axial rotation and a smaller magnitude of normal axial rotation reduce weightbearing knee flexion. This is likely the result of increased posterior movement of the lateral condyle and is an important consideration in future implant designs.

The effect of knee flexion contracture following total knee arthroplasty on the energy cost of walking

This study evaluated the energy cost of walking (Cw) with knee flexion contractures (FC) simulated with a knee brace, in total knee arthroplasty (TKA) recipients (n=16) and normal controls (n=15), and compared it to baseline (no brace). There was no significant difference in Cw between the groups at baseline but TKA recipients walked slower (P=0.048) and with greater knee flexion in this condition (P=0.003). Simulated FC significantly increased Cw in both groups (TKA P=0.020, control P=0.002) and this occurred when FC exceeded 20° in the TKA group and 15° in the controls. Reported perceived exertion was only significantly increased by FC in the control group (control P<0.001, TKA P=0.058). Simulated knee FCs less than 20° do not increase Cw or perceived exertion in TKA recipients.

Joint loading asymmetries in knee replacement patients observed both pre- and six months post-operation

BACKGROUND

Studies have highlighted asymmetries in knee joint moments in individuals with osteoarthritis and joint replacements. However, there is a need to investigate the forces at the knee joints to establish the extent of loading asymmetries.

METHODS

Twenty healthy (mean age, 62; range, 55-79 years) and 34 pre- to post-knee arthroplasty (mean age, 64; range, 39-79 years) participants performed gait and sit-stand activities in a motion capture laboratory. Knee joint forces and moments were predicted using inverse dynamics and used to calculate peak loading and impulse data which were normalized to body weight. Comparisons were made between affected and contralateral limbs, and changes from pre- to post-knee arthroplasty.

FINDINGS

Pre-knee arthroplasty peak vertical knee forces were greater in the contralateral limb compared to the affected limb during both gait 3.5 vs. 3.2 ∗ body weight and sit-stand 1.8 vs. 1.5 ∗ body weight. During gait, peak knee adduction moment asymmetries significantly changed from pre- to post-knee arthroplasty (-0.3 to 0.8 ∗ % body weight ∗ m ∗ height), although differences in vertical knee forces remained. There were no significant changes in loading during sit-stand from pre- to post-knee arthroplasty. The healthy participants showed no noteworthy asymmetries.

INTERPRETATION

This study showed loading asymmetries in knee forces between affected and contralateral limbs both pre- and post-knee arthroplasty. Continued over reliance of the contralateral limb could lead to pathology.

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

We investigated the biomechanical changes that occur in the lower limb following total knee arthroplasty (TKA). Lower limb joint kinematics and kinetics were evaluated in 32 patients before and 12 months following TKA and 28 age-matched controls. Analysis of variance with Bonferroni-adjusted post-hoc tests showed no significant changes in knee joint kinematics and kinetics following TKA despite significant improvements in pain and function. Significant increases in peak ankle plantarflexion and dorsiflexion moments and ankle power generation were observed which may be a compensatory response to impaired knee function to allow sufficient power generation for propulsion. Differences in knee gait parameters may arise as a result of the presence of osteoarthritis and mechanical changes associated with TKA as well as retention of the pre-surgery gait pattern.