Changes in knee adduction moment,pain, and functionality with a variable‐stiffness walking shoe after 6 months

This study tested the effects of variable‐stiffness shoes on knee adduction moment, pain, and function in subjects with symptoms of medial compartment knee osteoarthritis over 6 months. Patients were randomly and blindly assigned to a variable‐stiffness intervention or constant‐stiffness control shoe. The Western Ontario and McMaster Universities (WOMAC) score served as the primary outcome measure. Joint loading, the secondary outcome measure, was assessed using the external knee adduction moment. Peak external knee adduction moment, total WOMAC, and WOMAC pain scores were assessed at baseline and after 6 months. The total WOMAC and WOMAC pain scores for the intervention group were reduced from baseline to 6 months (p = 0.017 and p = 0.002, respectively), with no significant reductions for the control group. There was no difference between groups in magnitude of the reduction in total WOMAC (p = 0.50) or WOMAC pain scores (p = 0.31). The proportion of patients achieving a clinically important improvement in pain was greater in the intervention group than in the control group (p = 0.012). The variable‐stiffness shoes reduced the peak knee adduction moment (?6.6% vs. control, p < 0.001) in the 34 intervention subjects at 6 months. The adduction moment reduction significantly improved (p = 0.03) from the baseline reduction. The constant‐stiffness control shoe increased the peak knee adduction moment (+6.3% vs. personal, p = 0.004) in the 26 control subjects at 6 months. The results of this study showed that wearing the variable‐stiffness shoe lowered the adduction moment, reduced pain, and improved functionality after 6 months of wear. The lower adduction moment associated with wearing this shoe may slow the rate of progression of osteoarthritis after long‐term use. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:873–879, 2010     

Effect of variable-stiffness walking shoes on knee adduction moment, pain, and function in subjects with medial compartment knee osteoarthritis after 1 year

This study investigated the load‐modifying and clinical efficacy of variable‐stiffness shoes after 12 months in subjects with medial compartment knee osteoarthritis. Subjects who completed a prior 6‐month study were asked to wear their assigned constant‐stiffness control or variable‐stiffness intervention shoes during the remainder of the study. Changes in peak knee adduction moment, total Western Ontario and McMaster Universities (WOMAC), and WOMAC pain scores were assessed. Seventy‐nine subjects were enrolled, and 55 completed the trial. Using an intention‐to‐treat analysis, the variable‐stiffness shoes reduced the within‐day peak knee adduction moment (?5.5%, p < 0.001) in the intervention subjects, while the constant‐stiffness shoes increased the peak knee adduction moment in the control subjects (+3.1%, p = 0.015) at the 12‐month visit. WOMAC pain and total scores for the intervention group were significantly reduced from baseline to 12 months (?32%, p = 0.002 and ?35%, p = 0.007, respectively). The control group had a reduction of 27% in WOMAC pain score (p = 0.04) and no significant reduction in total WOMAC score. Reductions in WOMAC pain and total scores were similar between groups (p = 0.8 and p = 0.47, respectively). In the intervention group, reductions in adduction moment were related to improvements in pain and function (R² = 0.11, p = 0.04). Analysis by disease severity revealed greater efficacy in adduction moment reduction in the less severe intervention group. While the long‐term effects of the intervention shoes on pain and function did not differ from control, the data suggest wearing the intervention shoe reduces the within‐day adduction moment after long‐term wear, and thus should reduce loading on the affected medial compartment of the knee. © 2011 Orthopaedic Research Society. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:514–521, 2012     

Contralateral cane use and knee joint load in people with medial knee osteoarthritis: the effect of varying body weight support

Objective

To evaluate the effect of varying body weight support (BWS) with contralateral cane use on medial knee load, measured by external knee adduction moment (KAM), in medial knee osteoarthritis (OA) participants. Influences of cane use technique, pain and malalignment on the cane’s load-reducing effects were investigated.

Method

Participants (n = 23) underwent three-dimensional gait analysis to measure KAM peaks (early and late stance) and impulse. Unaided walking was firstly analyzed. Following cane use training, participants placed pre-determined magnitudes of BWS through the cane (10%, 15% and 20% in random order), with visual feedback provided via a force-instrumented cane and projection screen. Contributions of cane use technique (peak BWS magnitude and timing, cane impulse (BWS∗time) anterior and lateral cane distance from limb) and Western Ontario McMaster Universities OA Index (WOMAC) pain and malalignment to KAM outcomes were evaluated using linear mixed models.

Results

Cane use reduced all KAM variables, with a dose–response effect apparent. Cane BWS impulse was important in reducing the early stance peak KAM (P < 0.001), peak BWS for late stance KAM (P < 0.001) and both BWS measures for KAM impulse reductions (P < 0.001). Variables contributing to efficacy of load-reduction differed across outcomes. Generally, greater reductions were achieved with longer lateral cane distances, peak BWS timing similar to KAM peaks, and shorter anterior cane distances. Greater pain and varus alignment improved load-reduction for some outcomes.

Conclusion

Contralateral cane use significantly reduced medial knee load, with a dose–response effect. Medial knee OA patients should be encouraged to maintain greater BWS across stance, with cane placement more lateral for optimum benefit.     

对侧膝关节疼痛对全膝关节置换手术患者的临床影响

目的:评估对侧膝关节疼痛程度对骨性关节炎患者全膝关节置换术(total knee arthroplasty,TKA)后1年手术侧关节功能障碍及治疗满意度的影响。方法:2019年3月至2021年1月行TKA的635例患者,男296例,女339例;年龄(69.33±9.38)岁,病程(1.15±0.44)年。根据术后对侧膝关节疼痛视觉模拟评分(visual analogue scale,VAS)分为轻度或无疼痛(VAS 0～3分)423例,中度疼痛(VAS 4～6分)105例,重度疼痛(VAS 7～10分)107例。分析比较对侧膝关节不同疼痛程度对术后12个月膝关节功能及满意度评分的影响。结果:对侧膝关节疼痛VAS在TKA术后明显降低,年龄大、身体质量指数高、术后手术侧膝关节WOMAC评分高、对侧膝关节中、重度疼痛是患者不满意的危险因素(P<0.05),OR分别为1.285、1.665、2.319、1.863。手术侧膝关节疼痛度高、居家环境为步梯房是患者出院1年后WOMAC评分高的危险因素(P<0.05);出院后坚持锻炼、功能性训练是患者出院1年后WOMAC评分高的保护因素(P...     

Local bone quality affects the outcome of prosthetic total knee arthroplasty

Osteoporosis and osteoarthritis commonly coexist in the elderly. In patients undergoing prosthetic total knee arthroplasty (TKA), the bone quality around the knee joint may affect the safety of prosthetic implantation and consequently satisfaction with the surgical outcome. We recruited 50 postmenopausal women undergoing TKA for primary osteoarthritis; 43 completed the study protocol. The bone quality parameters of the operated knee, including bone mineral density assessed using dual‐energy X‐ray absorptiometry and microarchitecture variables assessed using micro‐computed tomography, were determined. Surgical outcomes were assessed according to immediate (<1 week) postoperative pain quantified using the visual analog scale and knee function quantified using the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 2 and 6 months postoperatively. The influence of bone quality parameters on surgical outcomes was analyzed using simple and multiple regression analyses. Volumetric bone mineral density (R² = 0.187–0.234, p < 0.01), the structural model index (R² = 0.103–0.181, p < 0.05), and trabecular separation (R² = 0.289–0.424, p < 0.05) were significantly associated with postoperative pain and improvement according to the KOOS. In conclusion, local bone quality, including mineral content and microarchitecture, affects the surgical outcome of TKA. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:240–248, 2016.     

Knee and ankle biomechanics with lateral wedges with and without a custom arch support in those with medial knee osteoarthritis and flat feet

This study compared immediate changes in knee and ankle/subtalar biomechanics with lateral wedge orthotics with and without custom arch support in people with knee osteoarthritis and flat feet. Twenty‐six participants with radiographic evidence of medial knee osteoarthritis (22 females; age 64.0 years [SD 8.0 years], BMI 27.2 kg/m² [4.2]) and flat feet (median foot posture index = + 5) underwent three‐dimensional gait analysis for three conditions: Control (no orthotic), lateral wedge, and lateral wedge plus arch support. Condition order was randomized. Outcomes included frontal plane knee and ankle/subtalar biomechanics, and comfort. Compared to the control, lateral wedge and lateral wedge with arch support reduced the knee adduction moment impulse by 8% and 6%, respectively (p < 0.05). However, the lateral wedge resulted in a more everted foot position (4.3 degrees) than lateral wedge plus arch support (3.2 degrees) (p < 0.05). In contrast, lateral wedge plus arch support reduced foot frontal plane excursion compared to other conditions (p < 0.05). Participants self‐reported significantly more immediate comfort with lateral wedge plus arch support compared to the control, whereas there was no difference in self‐reported comfort between lateral wedge and control. No immediate changes in knee pain were observed in any condition. Clinical significance: Rather than prescribing lateral wedges to all patients with knee osteoarthritis, those who have medial knee osteoarthritis and flat feet may prefer to use the combined orthotic to reduce loads across the knee, and to minimize the risk of foot and ankle symptoms as a consequence of orthotic treatment. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1597–1605, 2016.     

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

PurposeRobot-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.MethodsPatients 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.ResultsThere 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).ConclusionThe 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.     

Gait training for chronic ankle instability improves neuromechanics during walking

A novel gait‐training device has been shown to improve gait patterns while patients with chronic ankle instability (CAI) are using the device and our current objective was to analyze the effect of structured gait training with the device on plantar pressure and surface electromyography (sEMG) following repeated gait training sessions. Sixteen CAI patients participated. Plantar pressure and sEMG were collected simultaneously during walking pre‐ and post‐gait training. Plantar pressure (pressure time integral, peak pressure, time to peak pressure, contact area, contact time, and center of pressure trajectory) of the entire foot and nine specific regions of the foot were recorded concurrently with sEMG root mean square amplitudes from the anterior tibialis, peroneus longus, medial gastrocnemius, and gluteus medius. Five gait training sessions were performed with each session lasting approximately 15 min. Pre‐ and post‐gait training self‐reported function, plantar pressure, and sEMG were compared using paired t‐tests with a priori level of significance of p ≤ 0.05. Gait training improved self‐reported function (FAAM‐Sport scale: Pre = 75.1 ± 7.1%, Post = 85.7 ± 12.2%, p < 0.001) and caused a medial shift in the COP from 10% of stance through toe‐off (p < 0.05 for all analyses). The medial shift in COP was driven by concurrent increases in peroneus longus muscle activity from 21% to 60% and 81% to 90% of stance (p < 0.05 for all analyses). There was a corresponding reduction in gluteus medius muscle activity during 71–100% of stance (p < 0.05 for all analyses). Overall, gait training with a device that targets the peroneus longus and gluteus medius throughout the gait cycle improved gait patterns in CAI patients. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:515–524, 2018.     

Analgesic efficacy of subcutaneous local anaesthetic wound infiltration in bilateral knee arthroplasty: a randomised,placebo‐controlled,double‐blind trial

Background: High‐volume wound local infiltration analgesia is effective in knee arthroplasty, but the analgesic efficacy of subcutaneous wound infiltration has not been evaluated. Methods: In a randomised, double‐blind, placebo‐controlled trial in 16 patients undergoing bilateral knee arthroplasty with high‐volume local infiltration analgesia in the deeper layers, saline or ropivacaine 2 mg/ml was infiltrated into the subcutaneous part of the wound in each knee along with the placement of multi‐fenestrated catheters in the subcutaneous wound layers in both knees. Pain was assessed for 6 h post‐operatively and for 3 h after a bolus injection given through the catheter 24 h post‐operatively. Results: Visual analogue scale (VAS) pain scores were significantly lower from the knee infiltrated with ropivacaine compared with the knee infiltrated with saline in the subcutaneous layer of the wound, at rest (P<0.02), with flexion of the knee (P<0.04) and when the leg was straight and elevated (P<0.04). Twenty‐four hours post‐operatively, a decline in the VAS pain scores was observed in both groups, with no statistically significant difference between injection of ropivacaine or saline in the subcutaneously placed catheters (P>0.05). Conclusion: As part of a total wound infiltration analgesia intraoperative subcutaneous infiltration with ropivacaine in bilateral total knee arthroplasty is effective in early post‐operative pain management, while a post‐operative subcutaneous bolus administration through a multiholed catheter 24 h post‐operatively did not show improved analgesia compared with the administration of saline.     

Changes in the total knee joint moment in patients with medial compartment knee osteoarthritis over 5 years

Progression of medial compartment knee osteoarthritis (OA) has been associated with repetitive mechanical loading during walking, often characterized by the peak knee adduction (KAM) and knee flexion moments (KFM). However, the relative contributions of these components to the knee total joint moment (TJM) can change as the disease progresses since KAM and KFM are influenced by different factors that change over time. This study tested the hypothesis that the relative contributions of KAM, KFM, and the rotational moment (KRM) to the TJM change over time in subjects with medial compartment knee OA. Patients with medial compartment knee OA (n = 19) were tested walking at their self‐selected speed at baseline and a 5‐year follow‐up. For each frame during stance, the TJM was calculated using the KAM, KFM, and KRM. The peaks of the TJM and the relative contributions of the moment components at the time of the peaks of the TJM were tested for changes between baseline and follow‐up. The percent contribution of KFM to the first peak of the TJM (TJM1) significantly decreased (p < 0.001) and the percent contribution of KAM to TJM1 significantly increased (p < 0.001), while the magnitude of the TJM1 did not significantly change over the 5‐year follow‐up. These gait changes with disease progression appear to maintain a constant TJM1, but the transition from a KFM to a KAM dominance appears to reflect gait changes associated with progressing OA and pain. Thus, the TJM and its component analysis captures a comprehensive metric for total loading on the knee over time. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. 36:2373–2379, 2018.

     

Evidence and mechanism by which upper partial fibulectomy improves knee biomechanics and decreases knee pain of osteoarthritis

To investigate the change in short‐term clinical outcomes and biomechanical properties of the knee in response to upper partial fibulectomy and to probe into the biomechanical mechanism underlying the clinical benefits of upper partial fibulectomy for medial compartment knee osteoarthritis (KOA). A total of 29 patients with medial compartment KOA underwent upper partial fibulectomy. Visual analog scale (VAS) pain, the hospital for special surgery knee score (HSS), hip‐knee‐ankle (HKA) angle (measured in the frontal plane), and flexion/extension range of motion of the knee were assessed before and up to 6 months after surgery. Patients and 20 healthy controls were evaluated by 3D gait analysis and dynamic lower limb musculoskeletal analysis. Both VAS pain and HSS score were significantly improved (p < 0.001) one day after surgery and steadily improved during the subsequent 6 months. HKA angle improved (p = 0.025) immediately and remained stable by 3 months after surgery. The decreased overall peak KAM (decreased by 11.1%) and increased HKA angle (increased by 1.80 degrees from a more varus to more neutral alignment) of affected and operated side by 6 months after surgery were observed. Muscle activity of biceps femoris caput longum of affected and operated side increased immediately and was equivalent to healthy controls by 6 months after surgery (p = 0.007). This pilot study provides biomechanical evidence of benefit from partial upper fibulectomy and indicates a plausible rationale for the improvement in clinical symptoms. Long‐term clinical outcomes and precise biomechanical mechanism of partial upper fibulectomy should be further investigated. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2099–2108, 2018.

     

General scheme to reduce the knee adduction moment by modifying a combination of gait variables

Reducing the knee adduction moment (KAM) is a promising treatment for medial compartment knee osteoarthritis (OA). Although several gait modifications to lower the KAM have been identified, the potential to combine modifications and individual dose‐responses remain unknown. This study hypothesized that: (i) there is a general scheme consisting of modifications in trunk sway, step width, walking speed, and foot progression angle that reduces the KAM; (ii) gait modifications can be combined; and (iii) dose‐responses differ among individuals. Walking trials with simultaneous modifications in step width, walking speed, progression angle, and trunk sway were analyzed for 10 healthy subjects. Wider step width, slower speed, toeing‐in, and increased trunk sway resulted in reduced first KAM peak, whereas wider step width, faster speed, and increased trunk sway reduced the KAM angular impulse. Individual regressions accurately modeled the amplitude of the KAM variables relative to the amplitude of the gait modification variables, while the dose‐responses varied strongly among participants. In conclusion, increasing trunk sway, increasing step width, and toeing‐in are three gait modifications that could be combined to reduce KAM variables related to knee OA. Results also indicated that some gait modifications reducing the KAM induced changes in the knee flexion moment possibly indicative of an increase in knee loading. Taken together with the different dose‐responses among subjects, this study suggested that gait retraining programs should consider this general scheme of modifications with individualization of the modification amplitudes. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1547–1556, 2016.     

Longitudinal Changes in the Total Knee Joint Moment After Anterior Cruciate Ligament Reconstruction Correlate With Cartilage Thickness Changes

This study investigated associations between changes in the total joint moment (TJM) at the knee and changes in cartilage thickness after anterior cruciate ligament reconstruction (ACLR). Seventeen subjects (five males; age: 29.6 ± 7.3 years) with unilateral ACLR underwent gait analysis and magnetic resonance imaging at baseline (2.2 ± 0.3 years post‐ACLR) and at long‐term follow‐up (7.7 ± 0.7 years post‐ACLR). Knee loading was assessed using the TJM, and differences in loading were analyzed using repeated measures analysis of variance. Pearson correlation coefficients assessed associations between changes in TJM and changes in (medial‐to‐lateral) M/L femoral cartilage thickness ratios in the ACLR limb. Bilaterally, there was no significant change in the magnitude of the TJM first peak (TJM1), however, there was a significant increase in the percent contribution of the knee flexion moment (KFM) (p < 0.001) and decrease in the percent contribution of the knee adduction moment (KAM) to TJM1 (p < 0.001). The change in the percent contributions of KFM and KAM to TJM1 were associated with changes in M/L femoral cartilage thickness in the ACLR limb. Specifically, subjects with smaller increases in KFM contribution (R = 0.521, p = 0.032) and smaller decreases in KAM contribution (R = ?0.521, p = 0.032) had a reduction in the M/L ratio in the central femoral subregion over the follow‐up period, with similar trends in the external femoral subregion. The study results provide new insight into changes in the loading environment at the knee joint prospectively following ACL reconstruction and give evidence that there are modifiable gait metrics that are associated with cartilage changes after ACLR. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1546–1554, 2019.     

Decreased knee adduction moment does not guarantee decreased medial contact force during gait

Excessive contact force is believed to contribute to the development of medial compartment knee osteoarthritis. The external knee adduction moment (KAM) has been identified as a surrogate measure for medial contact force during gait, with an abnormally large peak value being linked to increased pain and rate of disease progression. This study used in vivo gait data collected from a subject with a force‐measuring knee implant to assess whether KAM decreases accurately predict corresponding decreases in medial contact force. Changes in both quantities generated via gait modification were analyzed statistically relative to the subject's normal gait. The two gait modifications were a “medial thrust” gait involving knee medialization during stance phase and a “walking pole” gait involving use of bilateral walking poles. Reductions in the first (largest) peak of the KAM (32–33%) did not correspond to reductions in the first peak of the medial contact force. In contrast, reductions in the second peak and angular impulse of the KAM (15–47%) corresponded to reductions in the second peak and impulse of the medial contact force (12–42%). Calculated reductions in both KAM peaks were highly sensitive to rotation of the shank reference frame about the superior–inferior axis of the shank. Both peaks of medial contact force were best predicted by a combination of peak values of the external KAM and peak absolute values of the external knee flexion moment (R² = 0.93). Future studies that evaluate the effectiveness of gait modifications for offloading the medial compartment of the knee should consider the combined effect of these two knee moments. Published by Wiley Periodicals, Inc. J Orthop Res 28:1348–1354, 2010     

Knee extensor and flexor dominant gait patterns increase the knee frontal plane moment during walking

High gait‐induced knee frontal plane moment is linked with the development of knee osteoarthritis. Gait patterns across the normal population exhibit large inter‐individual variabilities especially at the knee sagittal plane moment profile during loading response and terminal stance phase. However, the effects of different gait patterns on this moment remain unknown. Therefore, we examined whether different gait patterns are associated with atypically high knee frontal plane moments. Profiles of knee joint moments divided a sample of 24 subjects into three subgroups (11, 7, 6) through cluster analysis. Kinetics, kinematics, and spatio‐temporal parameters were compared among clusters. Subjects who showed a typical sagittal plane moment pattern (n = 11) had 43% lower first peak of knee frontal plane moment compared to the cluster, which showed the dominance of the knee extensor moment during stance phase (n = 7, p < 0.01). In addition, a typical gait pattern cluster had 44% lower second peak knee frontal plane moment than the cluster, which showed the dominance of the knee flexor moment during the terminal stance phase (n = 6, p < 0.05). These findings indicate that different knee strategies driving gait considerably impact knee loading, suggesting that knee extensor and flexor dominant gait patterns demonstrate atypically high knee frontal plane moments. People in these subgroups may, therefore, be at higher risk of developing knee osteoarthritis. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1013–1019, 2013     

Immediate and short‐term effects of real‐time knee adduction moment feedback on the peak and cumulative knee load during walking

The peak external knee adduction moment (pKAM), KAM impulse, and peak knee flexion moment (pKFM) during gait are important loading variables in medial tibiofemoral osteoarthritis. We evaluated the effects of gait modification, using real‐time pKAM visual feedback, on pKAM, KAM impulse, and pKFM; and whether participants could maintain the KAM‐reducing gait after feedback removal. Eleven healthy individuals performed a series of walking trials on a split‐belt instrumented treadmill under four conditions of Baseline, Feedback, No Feedback Early, and No Feedback Late. Guided by real‐time feedback of pKAM, they modified their gait patterns to lower pKAM by 20%. Three‐dimensional joint kinematics/kinetics during each walking condition were recorded by a 12‐camera motion capture system and the instrumented treadmill. Change in each knee loading parameter from baseline across conditions was assessed using one‐way repeated‐measures analysis‐of‐variances. In the feedback limb, successful 20% reductions from baseline in pKAM and KAM impulse were achieved across all three conditions. There was a trend for concomitant pKFM increases, partially attenuating the beneficial effects of pKAM reduction. A carry‐over effect of KAM reduction in the non‐feedback limb was noted. The altered gait patterns were participant‐specific and multi‐modal; each participant reported a combination of two to three gait modification strategies used for pKAM reduction. Toe‐in and medial foot contact were the most reported strategies. The findings support the real‐time pKAM visual feedback as a tool for individualized gait modification to reduce knee load. Future studies to evaluate its effectiveness in persons with or at risk for medial knee osteoarthritis is warranted. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:397–404, 2018.     

A pilot study of post-total knee replacement gait rehabilitation using lower limbs robot-assisted training system

The aim of this study was to explore the application value of the lower limbs robot-assisted training system for post-total knee replacement (TKR) gait rehabilitation. A total of 60 patients with osteoarthritis of the knee were equally randomized into the traditional and robot-assisted rehabilitation training groups within 1 week after TKR. All patients received 2-week training. Scores of hospital for special surgery (HSS), knee kinesthesia grades, knee proprioception grades, functional ambulation (FAC) scores, Berg balance scores, 10-m sitting–standing time, and 6-min walking distances were compared between the groups. The HSS score, Berg score, 10-m sitting–standing time, and 6-min walking distance of the robot-assisted training group were significantly higher than the control group (P < 0.05). Its knee kinesthesia grade, knee proprioception grade, and FAC score were better than the control group but not significantly (P > 0.05). Lower limbs robot-assisted rehabilitation training improves post-TKR patients’ knee proprioception and stability more effectively compared with the traditional method. It improves patients’ gait and symptoms, increases their walking speed, and prolongs their walking distances, which benefit their return to family and society.     

Pregabalin reduces post-operative pain after mastectomy: a double-blind, randomized, placebo-controlled study

Background: Pregabalin is used for the treatment of neuropathic pain and has shown analgesic efficacy in post‐operative pain. The aim of this randomized, double‐blinded, placebo‐controlled trial (Clinical Trials.gov ID NCT00938548) was to investigate the efficacy and safety of pregabalin for reducing post‐operative pain in patients after mastectomy. Methods: Eighty‐four women scheduled for elective mastectomy were randomly assigned to groups that received either pregabalin (75 mg) or placebo, 1 h before surgery and 12 h after the initial dose. Assessments of pain [verbal numerical rating scale (VNRS), at rest and with arm abduction] and side effects were performed at 1, 6, 24 and 48 h post‐operatively. After discharge from the hospital, pain was assessed by telephone interview at post‐operative 1 week and 1 month. Results: VNRS scores for pain at rest were lower in the pregabalin group (n=42) than the placebo group (n=42) at 1, 24 and 48 h post‐operatively (P<0.05). VNRS scores for pain with arm abduction were lower in the pregabalin group (n=42) than the placebo group (n=42) at 1 and 24 h, and 1 week post‐operatively (P<0.05). Incidences of side effects such as nausea and vomiting, headache, dizziness and blurred vision were similar in both groups. Conclusion: Perioperative administration of pregabalin for a single day (75 mg twice daily) was easy, safe and effective in reducing post‐operative pain in patients undergoing mastectomy.     

Sex differences in knee joint loading: Cross‐sectional study in geriatric population

This study investigated sex differences in knee biomechanics and investigated determinants for difference in a geriatric population. Age‐matched healthy volunteers (42 males and 42 females, average age 65 years) without knee OA were included in the study. Subjects underwent physical examination on their knee and standing full‐limb radiography for anthropometric measurements. Linear, kinetic, and kinematic parameters were compared using a three‐dimensional, 12‐camera motion capture system. Gait parameters were evaluated and determinants for sex difference were evaluated with multiple regression analysis. Females had a higher peak knee adduction moment (KAM) during gait (p = 0.004). Females had relatively wider pelvis and narrower step width (both p < 0.001). However, coronal knee alignment was not significantly different between the sexes. Multiple regression analysis revealed that coronal alignment (b = 0.014, p < 0.001), step width (b = −0.010, p = 0.011), and pelvic width/height ratio (b = 1.703, p = 0.046) were significant determinants of peak KAM. Because coronal alignment was not different between the sexes, narrow step width and high pelvic width/height ratio of female were the main contributors to higher peak KAM in females. Sex differences in knee biomechanics were present in the geriatric population. Increased mechanical loading on the female knee, which was associated with narrow step width and wide pelvis, may play an important role in future development and progression of OA. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1283–1289, 2017.

     

Verification of biomechanical factors of gait related to medial knee loading in patients 6 Months after total knee arthroplasty

BackgroundThe knee adduction moment (KAM) is considered an index for estimating the knee mechanical load, and increased KAM peak and KAM impulse are related to increased medial knee load and progression of knee joint degeneration. We aimed to verify the biomechanical factors of gait related to medial knee loading in patients 6 months after TKA.MethodsThirty-nine women who underwent TKA were enrolled. A three-dimensional gait analysis was performed 6 months postoperatively to generate data on the lower limb joint angle, moment, and power at the backward component (braking phase) and forward component (propulsion phase) peaks of the ground reaction force. Medial knee loading was evaluated using the time-integrated value of KAM during the stance period (KAM impulse). The higher the value of the KAM impulse, the higher the medial knee joint load. The relationships between the KAM impulse and the data for biomechanical factors were evaluated using partial correlation analysis with gait speed as a control factor.ResultsIn the braking phase, the KAM impulse positively correlated with the knee adduction angle (r = 0.377) and negatively correlated with the toe-out angle (r = −0.355). The KAM impulse positively correlated with the knee adduction angle (r = 0.402), the hip flexion moment (r = 0.335), and the hip adduction moment (r = 0.565) and negatively correlated with the toe-out angle (r = −0.357) in the propulsive phase.ConclusionThe KAM impulse 6 months after TKA was related to the knee adduction angle, hip flexion moment, hip adduction moment, and toe-out angle. These findings may provide fundamental data for controlling variable medial knee joint load after TKA and implementing patient management strategies to ensure implant durability.