Objectives. The purpose of this study was to evaluate the impact of multi-radius (MR, n=20) versus gradually reducing radius (GR, n=18) knee design on the kinematics and kinetics of the knee during level ground walking one year after total knee arthroplasty. Materials and Methods. Thirty-eight knees with end-stage knee osteoarthritis were examined before and one year after total knee arthroplasty. The groups consisted of subjects who had undergone total knee arthroplasty with a representative MR designed implant (B Braun-Aesculap Vega. ®. Knee System) and a representative GR designed implant (Depuy Attune. ®. Knee System) (Figure 1). The kinematic and kinetic parameters of knee varus angle, first peak knee adduction moment, sagittal plane knee excursion and extensor moment were evaluated during gait, as well as the spatiotemporal gait outcomes of walking speed, stride length, cadence, step length, the percentage of stance phase. Comparisons of preoperative and postoperative outcomes were done by the paired t-test. Independent t-test was also done to compare the postoperative outcomes of MR designed implant and GR designed implant. Results. In spatiotemporal parameters of GR implant group, there was an increase in walking speed, stride length and cadence (all p<0.05) and no change in step length and the percentage of stance phase postoperatively. GR implant group showed large reductions in varus angle and adduction moment (all p<0.001), a significant increase in extensor moment (p=0.01), and a small reduction in sagittal plane excursion (p=0.04) after surgery. In comparison of two groups at one year after surgery, there were no significant differences of all spatiotemporal, kinematic and kinetic parameters between two groups except varus angle. GR implant group showed more reduction in varus angle than MR implant group (p=0.01). Conclusions. Total knee arthroplasty performed with gradually reducing radius knee design reduces frontal plane loading patterns of knee varus angle and adduction moment and provided improvement in spatiotemporal parameters. Post-operatively there were no statistical differences between the MR implant group and the GR implant group in any of the kinematic and kinetic measures except knee varus angle during level ground walking

Gait analysis is an indispensable tool for scientific assessment and treatment of individuals whose ability to walk is impaired. The high cost of installation and operation are a major limitation for wide-spread use in clinical routine. Advances in Artificial Intelligence (AI) could significantly reduce the required instrumentation. A mobile phone could be all equipment necessary for 3D gait analysis. MediaPipe Pose provided by Google Research is such a Machine Learning approach for human body tracking from monocular RGB video frames that is detecting 3D-landmarks of the human body. Aim of this study was to analyze the accuracy of gait phase detection based on the joint landmarks identified by the AI system. Motion data from 10 healthy volunteers walking on a treadmill with a fixed speed of 4.5km/h (Callis, Sprintex, Germany) was sampled with a mobile phone (iPhone SE 2nd Generation, Apple). The video was processed with Mediapipe Pose (Version 0.9.1.0) using custom python software. Gait phases (Initial Contact - IC and Toe Off - TO) were detected from the angular velocities of the lower legs. For the determination of ground truth, the movement was simultaneously recorded with the AS-200 System (LaiTronic GmbH, Innsbruck, Austria). The number of detected strides, the error in IC detection and stance phase duration was calculated. In total, 1692 strides were detected from the reference system during the trials from which the AI-system identified 679 strides. The absolute mean error (AME) in IC detection was 39.3 ± 36.6 ms while the AME for stance duration was 187.6 ± 140 ms. Landmark detection is a challenging task for the AI-system as can clearly be seen be the rate of only 40% detected strides. As mentioned by Fadillioglu et al., error in TO-detection is higher than in IC-detection

Up to 20 percent of patients remain dissatisfied after primary total knee arthroplasty (TKA) surgery. Understanding the reasons for dissatisfaction post TKA may allow for better patient selection and optimized treatment for those who remain dissatisfied. The association between function, mobility and satisfaction are not well understood. The purpose of this study was to investigate the association between post-TKA satisfaction and i) pre-operative, ii) post-operative, and iii) change in knee joint function during gait. Thirty-one patients scheduled to receive primary TKA for knee osteoarthritis (OA) diagnosis were recruited and visited the Dynamics of Human Motion laboratory for instrumented walking gait analysis (using a synchronized NDI Optotrak motion capture system and AMTI force platforms in the walkway) at two time points, first within the week prior to their surgery, and second at approximately one year after surgery. At their post-operative visit, patients were asked to indicate their satisfaction with their knee prosthesis on a scale from zero to 100, with zero being totally unsatisfied and 100 being completely satisfied. Knee joint mechanics during gait at both time points were characterized by discriminant scores, the projection of their three-dimensional knee angles and moments during gait onto an existing discriminant model that was created to optimize separation of severe knee OA and healthy asymptomatic gait patterns. This discriminant model was created using data from 73 healthy participants and 73 with severe knee OA, and includes the magnitude and pattern features (captured with principal component analysis) of the knee adduction and flexion moment, and the magnitude of the knee flexion angle during gait. Larger discriminant scores indicate improved function toward healthy patterns, and smaller scores indicate more severe function. Associations between post-operative satisfaction and pre, post and change in discriminant scores were examined using Pearson correlation analyses. We also examined associations between satisfaction and pre-operative BMI, EQ5D and Oxford 12 scores, as well as changes in these scores from pre to post-TKA. Discriminant scores representing knee joint function during gait significantly improved on average after surgery (P =0.05). While overall knee joint function improved after primary TKA surgery, the amount of improvement in function was not reflected in post-operative patient satisfaction. However, the pre-operative function of the patient was negatively associated with satisfaction, indicating that patients with higher pre-operative function are overall less satisfied with their TKA surgery, regardless of any functional improvement due to the surgery. Interestingly, the only significant association with post-operative satisfaction was knee joint function, and the relationship between function and patient satisfaction following TKA appears to relate only to the baseline functional state of the patient, and not with functional improvement. This suggests that dissatisfaction post-surgery is more likely reflecting the unmet expectations of a higher functioning patient, and has implications for the need for improved understanding of pre-operative patient functional variability in TKA triage and expectation management

Patellofemoral osteoarthritis (PFOA) affects 32% men and 36% women over the age of 60years and is associated with anterior knee pain, stiffness, and poor mobility. Patellofemoral arthroplasty (PFA) is a bone-sparing treatment for isolated PFOA. This study set out to investigate the relationship between patient-related outcome measures (PROMs) and measurements obtained from gait analysis before and after PFA. There are currently no studies relating to gait analysis and PFA available in the literature. A prospective cohort study was conducted of ten patients known to have isolated PFOA who had undergone PFA compared to a gender and age matched control group. The patients were also asked to complete questionnaires (Oxford knee score (OKS), EQ-5D-5L) before surgery and one year after surgery. Gait analysis was done on an instrumented treadmill comparing Ground reaction force parameters between the control and pre and post-operative PFA patients. The average age 60 (49–69) years with a female to male ratio of 9:1. Patient and healthy subjects were matched for age and gender, with no significant difference in BMI. Post-op PFA improvement in gait seen in ground reaction force at 6.5km/h. Base support difference was statistically significant both on the flat P=0.0001 and uphill P=0.429 (5% inclination) and P=0.0062 (10% inclination). PROMS response rate was 70%(7/10) pre-operative and 60%(6/10) post-operative. EQ-5D-5L scores reflected patient health state was better post-operatively. This study found that gait analysis provides an objective measure of functional gait and reflected by significant quality-of-life improvement of patients post PFA. Literature lacks studies relating to gait-analysis and PFA. Valuable information provided by this study highlights that PFA has a beneficial outcome reflected by PROMs and improvement in vertical ground reaction force and gait. Further research is needed to assess how care-providers may use gait-analysis as part of patient care plans for PFOA patients

This study aimed to quantify self-reported outcomes and walking gait biomechanics in patients following primary and revision THA. The specific goals of this study were to investigate: (i) if primary and revision THA patients have comparable preoperative outcomes; and (2) if revision THA patients have worse postoperative outcomes than primary THA patients. Forty-three patients undergoing primary THA for osteoarthritis and 23 patients undergoing revision THA were recruited and followed longitudinally for their first 12 postoperative months. Reasons for revision were loosening (73%), dislocation (9%), and infection (18%). Patients completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS), and underwent gait analysis preoperatively, and at 3 and 12 months postoperatively. A 10 camera motion analysis system (V5 Vantage, Vicon, UK) recorded marker trajectories (100 Hz) during walking at self- selected speeds. A generic lower-body musculoskeletal model (Gait2392) was scaled using principal component analysis [1] and the inverse kinematics tool in Opensim 3.3 was used to compute joint angles for the lower limbs in the sagittal plane. Independent samples t-test were used to compare patient reported outcomes between the primary and revision groups at each timepoint. Statistical parametric mapping was used to compare gait patterns between the two groups at each timepoint. Preoperatively, patients undergoing primary THA reported significantly worse pain (p<0.001), symptoms (p<0.001), function (p<0.001), and quality of life (p=0.004). No differences were observed at 3 and 12 months postoperatively between patients who had received a primary or revision THA. The only observed difference in gait pattern was that patients with a revision THA had reduced hip extension at 3 months, but no differences were observed preoperatively and 12 months. Despite the suggestions in the literature that revision THA is bound to have worse outcomes compared to primary THA, we found no differences in in patient-reported outcomes and gait patterns at 12 months postoperatively. This suggests that it may be possible, in some circumstances, for patients following revision THA to achieve similar outcomes to their peers undergoing primary THA

The risk of falls in patients undergoing orthopedic procedures is particularly significant in terms of health and socioeconomic effects. The literature analyzed closely this risk following procedures performed on the lower limb, but the implications following procedures on the upper limb remain to be investigated. Interestingly, it is not clear whether the increased risk of falling in patients undergoing shoulder surgery is due to preexisting risk factors at surgery or postoperative risk factors, such as anesthesiologic effects, opioid medications used for pain control, or brace use. Only one prospective study examined gait and fall risk in patients using a shoulder abduction brace (SAB) after shoulder surgery, revealing that the brace adversely affected gait kinematics with an increase in the risk of falls. The main purpose of the study was to investigate the influence of SAB on gait parameters in patients undergoing shoulder surgery. Patients undergoing elective shoulder surgery (arthroscopic rotator cuff repair, reverse total shoulder arthroplasty, and Latarjet procedure), who used a 15° SAB in the postoperative period, were included. Conversely, patients age > 65 years old, with impaired lower extremity function (e.g., fracture sequelae, dysmorphism, severe osteo-articular pathology), central and peripheral nervous system pathologies, and cardiac/respiratory/vascular insufficiency were excluded. Participants underwent kinematic analysis at four different assessment times: preoperative (T0), 24 hours after surgery (T1), 1 week after surgery (T2), and 1 week after SAB removal (T3). The tests used for kinematic assessment were the Timed Up and Go (TUG) and the 10-meter test (10MWT), both of which examine functional mobility. Agility and balance were assessed by a TUG test (transitions from sitting to standing and vice versa, walking phase, turn-around), while gait (test time, cadence, speed, and pelvic symmetry) was evaluated by the 10MWT. Gait and functional mobility parameters during 10MWT and TUG tests were assessed using the BTS G-Walk sensor (G-Sensor 2). One-way ANOVA for repeated measures was conducted to detect the effects of SAB on gait parameters and functional mobility over time. Statistical analysis was performed with IBM®SPSS statistics software version 23.0 (SPSS Inc., Chicago, IL, USA), with the significant level set at p<0.05. 83% of the participants had surgery on the right upper limb. A main effect of time for the time of execution (duration) (p=0.01, η2=0.148), speed (p<0.01, η2=0.136), cadence (p<0.01, η2=0.129) and propulsion-right (R) (p<0.05, η2=0.105) and left (L) (p<0.01, η2=0.155) in the 10MWT was found. In the 10MWT, the running time at T1 (9.6±1.6s) was found to be significantly longer than at T2 (9.1±1.3s, p<0.05) and at T3 (9.0±1.3s, p=0.02). Cadence at T1 (109.7±10.9steps/min) was significantly lower than at T2 (114.3 ±9.3steps/min, p<0.01) and T3 (114.3±9.3steps/min, p=0.02). Velocity at T1 (1.1±0.31m/s) was significantly lower than at T2 (1.2± 0.21m/s, p<0.05). No difference was found in the pelvis symmetry index. No significant differences were found during the TUG test except for the final rotation phase with T2 value significantly greater than T3 (1.6±0.4s vs 1.4±0.3s, p<0.05). No statistically significant differences were found between T0 and T2 and between T0 and T3 in any of the parameters analyzed. Propulsion-R was significantly higher at T3 than T1 (p<0.01), whereas propulsion-L was significantly lower at T1 than T0 (p<0.05) and significantly higher at T2 and T3 than T1 (p<0.01). Specifically, the final turning phase was significantly higher at T2 than T3 (p<0.01); no significant differences were found for the duration, sit to stand, mid-turning and stand to sit phases. The results demonstrated that the use of the abduction brace affects functional mobility 24 hours after shoulder surgery but no effects were reported at longer term observations

The study compared thigh-shank and shank-foot coordination during gait before and after total knee arthroplasty (TKA) with controls (CTRL). Twenty-seven patients (male=15/female=12; age=63.2±6.9 years) were evaluated one month prior to and twelve months after surgery, and compared to 27 controls (male=14/female=13; age=62.2±4.3). The participants were outfitted with a full-body marker set. Gait speed (normalized by leg length) was calculated. The time series of the thigh, shank, and foot orientation in relation to the laboratory coordinate system were extracted. The coordination between the thigh-shank and shank-foot in the sagittal plane were calculated using a vector coding technique. The coupling angles were categorized into four coordination patterns. The stance phase was divided into thirds: early, mid, and late stance. The frequency of each pattern and gait speed were compared using a one-way ANOVA with a post-hoc Bonferroni correction. Walking speed and shank-foot coordination showed no differences between the groups. The thigh-shank showed differences. The pre-TKA group showed a more in-phase pattern compared to the CTRL group during early-stance. During mid-stance, the pre- and post-TKA presented a more in-phase pattern compared to the CTRL group. Regarding shank-foot coordination, the groups presented an in-phase and shank pattern, with more shank phase during mid-stance and more in-phase during late-stance. The pre-TKA group showed greater differences than the post-TKA compared to the controls. The more in-phase pattern in the pre- and post-TKA groups could relate to a reduced capacity for the thigh that leads the movement. During mid-stance in normal gait, the knee is extending, where the thigh and shank movements are in opposite directions. The in-phase results in the TKA groups indicate knee stiffness during the stance phase, which may relate to a muscular deficit or a gait strategy to reduce joint stress

Vacuum orthoses are being applied in the care of patients with foot and lower leg conditions, as ankle fractures or sprains. The lower leg is protected and immobilized, which increases mobility. Due to the design, the orthoses lead to a difference in leg length, i.e. the side with the orthosis becomes longer, which changes the gait kinematics. To prevent or mitigate the unfavourable effects of altered gait kinematics, leg length-evening devices (shoe lifts) are offered that are worn under the shoe on the healthy side. Our aim was to evaluate the effect of such a device on the normality of gait kinematics. Gait analysis was conducted with 63 adult, healthy volunteers having signed an informed consent form that were asked to walk on a treadmill at a speed of 4.5km/h in three different conditions:. barefoot - as reference for establishing the normality score baseline. with a vacuum orthosis (VACOPed, OPED GmbH, Germany) and a sport shoe. with a vacuum orthosis and a shoe lift (EVENup, OPED GmbH, Germany). Data was sampled using the gait analysis system MCU 200 (LaiTronic GmbH, Austria). The positions of the joint markers were exported from the software and evaluated for the joint angles during the gait cycle using custom software (implemented in DIAdem 2017, National Instruments). A normality score using a modification of the Gait Profile Score (GPS) was calculated in every 1%-interval of the gait cycle and evaluated with a Wilcoxon signed rank test. The GPS value was reduced by 0.33° (0.66°) (median and IQR) while wearing the shoe lift. The effect was statistically significant, and very large (W = 1535.00, p < .001; r (rank biserial) = 0.52, 95% CI [0.29, 0.70]). The significant reduction of the GPS value indicates a more normal gait kinematics while using the leg length-evening device on the contralateral shoe. This rather simple and inexpensive device thus might improve patient comfort and balance while using the vacuum orthoses

Purpose of Study. In children with spastic diplegia, surgery for equinus has a high incidence of both over and under correction. We wished to determine if conservative (mainly Zone 1) surgery for equinus gait, in the context of multilevel surgery, could result in the avoidance of calcaneus and crouch gait as well as an acceptable rate of recurrent equinus, at medium term follow-up. Description of Methods. This was a retrospective, consecutive cohort study of children with spastic diplegia, between 1996 and 2006. All children had distal gastrocnemius recession or differential gastrocsoleus lengthening, on one or both sides, as part of Single Event Multilevel Surgery. The primary outcome measures were the Gait Variable Scores (GVS) and Gait Profile Score (GPS) at two time points after surgery. Summary of Results. Forty children with spastic diplegia, GMFCS Level II and III were eligible for inclusion in this study. There were 25 boys and 15 girls, mean age 10 years at surgery. The mean age at final follow-up was 17 years and the mean postoperative follow-up period was seven years. The mean ankle GVS improved from 18.5° before surgery to 8.7° at short term follow-up (P<0.005) and 7.8° at medium term follow-up. Equinus gait was successfully corrected in the majority of children with a low rate of over-correction (2.5%) but a high rate of recurrent equinus (35.0%), as determined by sagittal ankle kinematics. Conclusion. Surgery for equinus gait, in children with spastic diplegia, was successful in the majority of children, at a mean follow-up of seven years, when combined with multilevel surgery, orthoses and rehabilitation. No patients developed crouch gait and the rate of revision surgery for recurrent equinus was 12.5%. NO DISCLOSURES

Due to abnormal neuromuscular development, functional capability in children with cerebral palsy is often severely compromised. Single event multi-level surgery (SEMLS) is the gold standard surgical treatment for patients with cerebral palsy. It has been demonstrated to improve gait, however, how standing posture is affected is unknown. The aim was to investigate the effect of SEMLS in patients with spastic cerebral palsy on walking and standing posture using 3D gait analysis. Participants were identified from the One Small Step Gait Laboratory database. Standardised 3D-Gait analysis was performed within 2 years pre- and post-SEMLS. Gait abnormality was measured using the Gait Profile Score (GPS) index; standing abnormality was measured using the newly-developed Standing Profile Score (SPS) index. A control group (n=20) of age/sex-matched CP patients who did not undergo surgery were also assessed. 104 patients (73 boys, 31 girls) with spastic cerebral palsy underwent SEMLS with appropriate pre- and post-gait analyses (2000–2015). 91 patients had bilateral limb involvement, 14 had unilateral limb involvement. Average age at surgery was 10.38 years (range 4.85–15.60 years). A total of 341 procedures were performed, with hamstring and gastrocnemius lengthening representing approximately 65% of this. There was a 20% mean improvement in walking (GPS reduced 2.4°, p<0.001) and standing (SPS reduced 3.4°, p<0.001) following SEMLS. No improvement was noted in the control group. Significant correlations were observed between the changes in SPS and GPS following surgery (r2, p<0.001). Patients with poorer pre-operative standing posture (SPS) reported the most significant improvement following surgery. We confirmed improvement in walking following SEMLS using the Gait Profile Score (GPS). This is the first paper to report that standing posture is also improved following surgery using a novel index, the Standing Posture Score (SPS). SPS could be adopted as a tool to assess functional capability and predict post-operative changes

Introduction. Limb deformity is usually assessed clinically assisted by long leg alignment radiographs and further imaging modalities (MRI and CT). Often decisions are made based on static imaging and simple gait interpretation in clinic. We have assessed the value of gait lab analysis in surgical decision making comparing surgical planning pre and post gait lab assessment. Materials & Methods. Patients were identified from the local limb reconstruction database. Patients were reviewed in the outpatient clinic and long leg alignment radiographs and a CT rotational limb profile were performed. A surgical plan was formulated and documented. All patients then underwent a formal gait lab analysis. The gait lab recommendations were then compared to the initial plan. Results. Twelve patients (8 female) with mean age of 14 (range 12–16) were identified. Nine were developmental torsional malalignments, one arthrogryposis, one hemiparesis secondary to spinal tumour resection and one syndromic limb deficiency. The gait lab recommended conservative management in four patients and agreed with eight surgical plans with one osteotomy level changing. Five patients are post-operative: two bilateral distal tibial osteotomies, two de-rotational femoral osteotomy with de-rotational tibial osteotomies and one bilateral femoral de-rotational osteotomies. Conclusions. Limb deformity correction is major surgery with long rehabilitation and recovery period. Gait lab analysis can identify who would benefit from conservative management rather than surgery with our study showing changes to surgical planning in one third of patients. The gait lab analysis helps to identify patients with functional and neuromuscular imbalances where correcting the bony anatomy may not actually benefit the patient

For clinical movement analysis, optical marker-based motion capture is the gold standard. With the advancement of AI-driven computer vision, markerless motion capture (MMC) has emerged. Validity against the marker-based standard has only been examined for lightly-dressed subjects as required for marker placement. This pilot study investigates how different clothing affects the measurement of typical gait metrics. Gait tests at self-selected speed (4 km/h) were performed on a treadmill (Motek Grail), captured by 9 cameras (Qualisys Miqus, 720p, f=100Hz) and analyzed by a leading MMC application (Theia, Canada). A healthy subject (female, h=164cm, m=54kg) donned clothes between trials starting from lightly dressed (LD: bicycle tight, short-sleeved shirt), adding a short skirt (SS: hip occlusion) or a midi-skirt (MS: partial knee occlusion) or street wear (SW: jeans covering ankle, long-sleeved blouse), the lattern combined with a short jacket (SWJ) or a long coat (SWC). Gait parameters (mean±SD, t=10s) calculated (left leg, mid-stance) were ankle pronation (AP-M), knee flexion (KF-M), pelvic obliquity (PO-M) and trunk lateral lean (TL-M) representing clinically common metrics, different joints and anatomic planes. Four repetitions of the base style (LD) were compared to states of increased garment coverage using the t-test (Bonferroni correction). For most gait metrics, differences between the light dress (LD) and various clothing styles were absent (p>0.0175), small (< 2SD) or below the minimal clinically important differences (MCID). For instance, KF-M was for LD=10.5°±1.7 versus MD=12.0°±0.5 (p=0.07) despite partial knee cover. AP-M measured for LD=5.2°±0.6 versus SW=4.1°±0.7 (p<0.01) despite ankle cover-up. The difference for KF-M between LD=10.5°±1.7 versus SWL=6.0°±0.9, SW and SWJ (7.6°±1.5, p<0.01) indicates more intra-subject gait variability than clothing effect. This study suggests that typical clothings styles only have a small clinically possibly negligible effect on common gait parameters measured with MMC. Thus, patients may not need to change clothes or be instructed to wear specific garments. In addition to avoiding marker placement, this further increases speed, ease and economy of clinical gait analysis with MMC facilitating high volume or routine application

A ceramic-on-ceramic hip resurfacing implant (cHRA) was developed and introduced in an MHRA-approved clinical investigation to provide a non metallic alternative hip resurfacing product. This study aimed to examine function and physical activity levels of patients with a cHRA implant using subjective and objective measures both before and 12 months following surgery in comparison with age and gender matched healthy controls. Eighty-two unilateral cHRA patients consented to this study as part of a larger prospective, non-randomised, clinical investigation. In addition to their patient reported outcome measures (PROMs), self- reported measures of physical activity levels and gait analysis were undertaken both pre- operatively (1.5 weeks) and post operatively (52 weeks). This data was then compared to data from a group of 43 age gender and BMI matched group of healthy controls. Kinetics and kinematics were recorded using an instrumented treadmill and 3D Motion Capture. Statistical parametric mapping was used for analysis. cHRA improved the median Harris Hip Score from 63 to 100, Oxford Hip score from 27 to 48 and the MET from 5.7 to 10.3. cHRA improved top walking speed (5.75km vs 7.27km/hr), achieved a more symmetrical ground reaction force profile, (Symmetry Index value: 10.6% vs 0.9%) and increased hip range of motion (ROM) (31.7° vs 45.9°). Postoperative data was not statistically distinguishable from the healthy controls in any domain. This gait study sought to document the function of a novel ceramic hip resurfacing, using those features of gait commonly used to describe the shortcomings of hip arthroplasty. These features were captured before and 12 months following surgery. Preoperatively the gait patterns were typical for OA patients, while at 1 year postoperatively, this selected group of patients had gait patterns that were hard to distinguish from healthy controls despite an extended posterior approach. Applications for regulatory approval have been submitted

Abstract. Objectives. Little is known about the impact of cartilage defects on knee joint biomechanics. This investigation aimed to determine the gait characteristics of patients with symptomatic articular cartilage lesions of the knee. Methods. Gait analyses were performed at the Regional North-West Joint Preservation Centre. Anthropometric measurements were obtained, then 16 retroreflective markers representing the Plug-in-Gait biomechanical model were placed on pre-defined anatomical landmarks. Participants walked for two minutes at a self-selected speed on a treadmill on a level surface, then for 2 minutes downhill. A 15-camera motion-capture system recorded the data. Knee kinematics were exported into Matlab to calculate the average kinematics and spatiotemporal parameters per patient across 20 gait cycles. Depending on the normality of the data, paired t-tests or Wilcoxon ranked tests were performed to compare both knees (α = 0.05). Results. 20 patients participated; one of whom has bilateral cartilage defects. All 20 data sets were analysed for level walking; 18 were analysed for downhill walking. On a level surface, patients walked at an average speed of 3.1±0.8km/h with a cadence of 65.5±15.3 steps/minute. Patients also exhibited equal step lengths (0.470±0.072m vs 0.471±0.070m: p=0.806). Downhill, the average walking speed was 2.85±0.5km/h with a cadence of 78.8±23.1 steps/minute and step lengths were comparable (0.416±0.09m vs 0.420±0.079m: p=0.498). During level walking, maximum flexion achieved during swing did not differ between knees (54.3±8.6° vs 55.5±11.0°:p=0.549). Neither did maximal extension achieved at heel strike (3.1±5.7° vs 5.4±4.7°:p=0.135). On average, both knees remained in adduction throughout the gait cycle, with the degree of adduction greater in flexion in the operative knee. However, differences in maximal adduction were not significant (22.4±12.4° vs 18.7±11.0°:p=0.307). Maximal internal-external rotation patterns were comparable in stance (0.9±7.7° vs 3.5±9.8°: p=0.322) and swing (7.7±10.9° vs 9.8±8.3°:p=0.384). During downhill walking, maximum flexion also did not differ between operative and contralateral knees (55.38±10.6° vs 55.12±11.5°:p=0.862), nor did maximum extension at heel strike (1.32±6.5° vs 2.73±4.5°:p=0.292). No significant difference was found between maximum adduction of both knees (15.87±11.0° vs 16.78±12.0°:p=0.767). In stance, differences in maximum internal-external rotation between knees were not significant (5.39±10.7° vs 6.10±11.8°:p=0.836), nor were they significant in swing (7.69±13.3° vs 7.54±8.81°:p=0.963). Conclusions. Knee kinematics during level and downhill walking were symmetrical in patients with a cartilage defect of the knee, but an increased adduction during flexion in the operative knee may lead to pathological loading across the medial compartment of the knee during high flexion activities. Future work will investigate this further and compare the data to a healthy young population. We will also objectively assess the functional outcome of this joint preservation surgery to monitor its success. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction. There is limited evidence assessing the effect of the Ankle Foot Orthosis (AFO) on gait improvements in diplegic cerebral palsy. In particular, the effect of the AFO on vertical forces during gait has not been reported. Appropriate vertical ground reaction forces are crucial in enabling children with CP to walk efficiently. This study investigated the effect of AFO application on the vertical forces in gait, particularly the second vertical peak in force (FZ2) in late stance. The force data was compared with the barefoot walk. Patients and Methods. A retrospective analysis of nineteen children (8M,11F) who met inclusion criteria of a diagnosis of spastic diplegic CP, ability to walk independently barefoot and also using bilateral rigid AFOs were included. Gait data were acquired using the Vicon-Nexus ® motion-capture. Resulting ground reaction force data were recorded. Appropriate statistical methods assessed significance between barefoot and AFO data. Results. 68.4% of subjects experienced increase in FZ2 magnitude in left leg and 63.2% experienced objective increase in right leg after AFO application. Mean increased in FZ2 was 5.33N in left leg and 8.53 N in right leg. Results indicate significant improvement in amplitude of FZ2 generation with AFO application, significantly increased gait efficiency, and a significantly normalized pattern of vertical force produced during gait. Discussion. The AFO is effective in enabling children with diplegic CP to achieve efficient gait patterns. Our study is the first to our knowledge that focuses on the effect of AFO on specifically vertical ground reaction force produced in gait

Introduction and Aims: We studied the outcome of single event multilevel surgery (SEMLS) for the correction of severe crouch gait in spastic diplegia, over a five-year period. It was unknown if gait correction post-SEMLS could be sustained at skeletal maturity. Method: This was a prospective cohort study, utilising validated outcome measures. Presenting symptoms were increasingly abnormal gait, anterior knee pain, patellar fractures and fatigue. SEMLS was based on pre-operative gait analysis: mean of seven procedures (range 5–10), including lengthening of contracted muscle-tendon units (particularly hamstrings and psoas), as well as rotational osteotomies and bony stabilisation procedures to correct lever arm dysfunction. Post-operatively subjects wore Ground Reaction Ankle Foot Orthoses (GRAFOs) and received a community-based rehabilitation program. Post-operative changes were evaluated at five years: technical outcome by 3D kinematics and functional outcome by mobility status. Outcomes were analysed with linear regression with robust standard errors. Results: Eleven children with spastic diplegic cerebral palsy fulfilled the criteria for ‘severe crouch gait’, defined as knee flexion > 30 degrees and ankle dorsiflexion > 15 degrees throughout stance. Ten of 11 subjects had previous Tendo Achilles lengthening. Mean age pre-operatively was 12 years one month (range 8–16) and at follow-up 17 years 10 months (range 16–21). All subjects regained pre-operative mobility levels with improved gait pattern, relief of knee pain and healing of patellar fractures. There was a significant decrease in dependence on assistive devices. Pre- versus five years post-operative kinematics showed clinically and statistically significant increases in knee extension and decreases in ankle dorsiflexion. Improvements were seen in knee extension initial contact (p< 0.001, 95% CI 15°, 31°); maximum knee extension (p< 0.001, 95% CI 16°, 37°), ankle dorsiflexion (p< 0.001, 95% CI 8°, 18°) and plantarflexion 3rd rocker in stance (p=0.03, 95% CI 1°, 17°); knee excursion (p=0.003, 95% CI –24°, −6°), and peak knee flexion timing (p=0.02, 95% CI 2%, 20%). Conclusion: Multilevel surgery for severe crouch gait in spastic diplegia results in consistently marked improvements in dynamic knee and ankle function, but not at the hip and pelvic levels. The results are durable in most patients, after five years and after reaching skeletal maturity

Introduction and Objective. Gait variability is the amplitude of the fluctuations in the time series with respect to the mean of kinematic (e.g., joint angles) or kinetic (e.g., joint moments) measurements. Although gait variability increases with normal ageing or pathological mechanisms, such as knee osteoarthritis (OA). The purpose was to determine if a patient who underwent a total knee arthroplasty (TKA) can reduce gait variability. Materials and Methods. Twenty-five patients awaiting TKA were randomly assigned to receive either medial pivot (MP, m=7/f=6, age=62.4±6.2 years) or posterior stabilized (PS, m=7/f=5, age=63.7±8.9 years) implants, and were compared to 13 controls (CTRL, m=7/f=6, age=63.9±4.3 years). All patients completed a gait analysis within one month prior and 12 months following surgery, CTRLs completed the protocol once. A waveform F-Test Method (WFM) was used to compare the variance in knee biomechanics variables at each interval of the gait cycle. Results. Preoperatively, the PS group had greater sagittal knee angle variability compared to the MP (32–58% gait cycle) and CTRL (21–53% gait cycle) groups. Postoperatively, no difference in sagittal knee angle variability existed between any of the groups. Preoperatively, sagittal knee moment variability was greater in the MP (2–39% gait cycle) and PS (5–19% and 42–57% gait cycle) groups compared to the CTRL. Postoperatively, sagittal knee moment was lower in the MP (49–55% gait cycle) and greater in the PS (23–36% gait cycle) compared to the CTRL. Knee power variability was greater preoperatively in the MP (52–61% gait cycle) and PS (52–62% gait cycle) compared to the CTRL. Postoperatively, knee power variability was lower in the MP (17–22% and 45–50% gait cycle) and PS (6–23%, 34–41% and 45–49% gait cycle) compared to the CTRL group. Conclusions. Preoperatively, knee OA patients have greater variability in knee moments than CTRLs during the transition from double-limb support to single-limb support on the affected limb. This indicates knee instability as patients are adopting a gait strategy that refers to knee muscle contraction avoidance. The MP group showed greater knee stability postoperatively as they had lower knee moment and power variability compared to the CTRL. The significance of having less variability than CTRLs is not well understood at this time. Future research on muscle activity is needed to determine if neuromuscular adaptations are causing these reductions in variability after TKA

Abstract. Objectives. 1. To investigate the effect of revision total knee replacement (TKR) on gait kinematics in patients with a primary TKR and instability.2. To compare gait kinematics between patients with a well-functioning TKR and those with a primary TKR and symptoms of instability. Methods. This single-centre observational study is following patients who have had a revision TKR due to knee instability. Data was collected pre- and post-operatively at 8–12 week follow-up. The data was compared to a control group of 18 well-functioning TKR patients. Kinematic gait data was collected during routine clinics using a treadmill-based infrared 3D system (Vicon, Oxford, UK) and a published lower limb marker-set. Patients performed 15 strides at three different speeds: 0.6mph, self-selected, and a ‘slow walk’ normalised to leg length (Froude number 0.09). PROMs questionnaires were collected. NHS ethical approval was obtained. Results. Data was collected for 18 well-functioning TKR patients and 8 revision TKR patients pre- and post-operatively, but only 5 could walk at the normalised speed. When walking at a normalised speed (Froude 0.09), patients with a TKR with instability had reduced range of knee flexion (52° (sd 14)) compared to those with a well-functioning TKR (59° (sd 11)). Short term follow-up after a revision TKR operation demonstrated a stiffer knee (45° (sd 12)). However, those with revision TKR had a more flexed knee during stance phase. Conclusions. At short-term follow-up, this cohort of revision TKR patients appear to have reduced flexion range, while remaining more flexed during stance. This may represent a less efficient gait pattern, which may also adversely affect the implant[1]. Longer term follow-up may demonstrate whether this normalises with post-operative rehabilitation. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Advances in algorithms developed with sensor data from smart phones demonstrates the capacity to passively collect qualitative gait metrics. The purpose of this feasibility study was to assess the recovery of these metrics following joint reconstruction. A secondary data analysis of an ethics approved global, multicenter, prospective longitudinal study evaluating gait quality data before and after primary total knee arthroplasty (TKA, n=476), partial knee arthroplasty (PKA, n=139), and total hip arthroplasty (THA, n=395). A minimum 24 week follow-up was required (mean 45±12, range 24 - 78). Gait bouts and gait quality metrics (walking speed, step length, timing asymmetry, and double support percentage) were collected from a standardized smartphone operating system. Pre- and post-operative values were compared using paired-samples t-tests (p<0.05). A total of 595 females and 415 males with a mean age of 61.9±9.3 years and mean BMI of 30.2±6.1 kg/m. 2. were reviewed. Walking speeds were lowest at post-operative week two (all, p<.001). Speeds exceeded pre-operative means consistently by week 21 (p=0.015) for PKA, and week 13 (p=0.007) for THA. The average weekly step length was lowest in post-operative week two (all, p<0.001). PKA and THA cases achieved pre-operative step lengths by week seven (p=0.064) and week 9 (p=0.081), respectively. The average weekly gait asymmetry peaked at week two post-operatively (all, p <0.001). Return to pre-operative baseline asymmetry was achieved by week 11 (p=0.371) for TKA, week six (p=0.541) for PKA, and week eight (p=.886) for THA. Double limb support percentages peaked at week two (all, p<0.001) and returned to pre-operative levels by week 24 (p=0.089) for TKA, week 12 (p=0.156) for PKA, and week 10 (p=0.143) for THA. Monitoring gait quality in real-world settings following joint reconstruction using smartphones is feasible, and may provide the advantage of removing the Hawthorne effect related to typical gait assessments and in-clinic observations

Abstract. Objectives. Although hip replacement and resurfacing procedures both aim to restore mobility, improve joint function, and relieve pain, it is unclear how each differ in terms of gait mechanics and if they are affected by varying walking speeds. We compared limb symmetry and ground reaction force (GRF) profiles between bilateral total hip arthroplasty patients (THA), bilateral hip resurfacing arthroplasty patients (HRA), and healthy control participants (CON) during level-treadmill walking at different speeds. Methods. Bilateral THA and bilateral HRA patients (nTHA = 15; nHRA = 15; postoperative 12–18 months), and age-, mass-, and height-matched CON participants (nCON = 20) underwent gait analysis on an instrumented treadmill. Walking trials started at 4 km/h and increased in 0.5 km/h increments until top walking speed (TWS) was achieved. Gait symmetry index (SI = 0% for symmetry) was assessed between limbs during weight-acceptance, mid-stance and push-off phases of gait; and vertical GRFs were captured for the normalised stance phase using statistical parametric mapping (SPM; CI = 95%). Results. THA had a significantly lower TWS (6.51 ± 0.06 km/h) compared to HRA (7.09 ± 0.07 km/h, p = 0.01) and CON (7.15 km/h ± 0.06, p = 0.02). There were no SI differences between groups nor between walking speeds (SI < 5%). There were no GRF differences between groups at slower walking speeds (4.0–5.0 km/h). However, at 5.5 and 6 km/h, THA had lower GRF at the push-off phase (0.88 ± 0.09 N/BW), compared to HRA (1.06 ± 0.08 N/BW, p = 0.01) and CON (1.04 ± 0.02 N/BW, p = 0.01). Conclusions. The main finding was that HRA patients demonstrated restored gait function and similar walking profiles to CON participants at any speed. With a diverging gait profile, walking speeds over 5.5 km/h provided a functional challenge for THA patients