Complications involving the patellofemoral joint, caused by malrotation of the femoral component during total knee replacement, are an important cause of persistent pain and failure leading to revision surgery. The aim of this study was to determine and quantify the influence of femoral component malrotation on patellofemoral wear, and to determine whether or not there is a difference in the rate of wear of the patellar component when articulated against oxidised zirconium (OxZr) and cobalt-chrome (CoCr) components. An in vitro method was used to simulate patellar maltracking for both materials. Both rates of wear and changes in height on the patellar articular surface were measured. The mean rates of wear measured were very small compared to standard tibiofemoral wear rates. When data for each femoral component material were pooled, the mean rate of wear was 0.19 mm³/Mcycle (sd 0.21) for OxZr and 0.34 mm³/Mcycle (sd 0.335) for CoCr. The largest change in height on each patella varied from -0.05 mm to -0.33 mm over the different configurations.

The results suggest that patellar maltracking due to an internally rotated femoral component leads to an increased mean patellar wear. Although not statistically significant, the mean wear production may be lower for OxZr than for CoCr components.

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

Aims. The standard of surgical treatment for lower limb neoplasms had been characterized by highly interventional techniques, leading to severe kinetic impairment of the patients and incidences of phantom pain. Rotationplasty had arisen as a potent limb salvage treatment option for young cancer patients with lower limb bone tumours, but its impact on the gait through comparative studies still remains unclear several years after the introduction of the procedure. The aim of this study is to assess the effect of rotationplasty on gait parameters measured by gait analysis compared to healthy individuals. Methods. The MEDLINE, Scopus, and Cochrane databases were systematically searched without time restriction until 10 January 2022 for eligible studies. Gait parameters measured by gait analysis were the outcomes of interest. Results. Three studies were eligible for analyses. Compared to healthy individuals, rotationplasty significantly decreased gait velocity (-1.45 cm/sec; 95% confidence interval (CI) -1.98 to -0.93; p < 0.001), stride length (-1.20 cm; 95% CI -2.31 to -0.09; p < 0.001), cadence (-0.83 stride/min; 95% (CI -1.29 to -0.36; p < 0.001), and non-significantly increased cycle time (0.54 sec; 95% CI -0.42 to 1.51; p = 0.184). Conclusion. Rotationplasty is a valid option for the management of lower limb bone tumours in young cancer patients. Larger studies, with high patient accrual, refined surgical techniques, and well planned rehabilitation strategies, are required to further improve the reported outcomes of this procedure. Cite this article: Bone Jt Open 2023;4(11):817–824

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 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

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

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

Introduction. A recent study to identify clinically meaningful benchmarks for gait improvement after total hip replacement (THA) has shown that the minimum clinically important improvement (MCII) in gait speed after THA is 0.32 m/sec. Currently, it remains to be investigated what preoperative factors link to suboptimal recovery of gait function after THA. This study aimed to identify preoperative lower-limb muscle predictors for gait speed improvement after THA for hip osteoarthritis. Method. This study enrolled 58 patients who underwent unilateral primary THA. Gait speed improvement was evaluated as the subtraction of preoperative speed from postoperative speed at 6 months after THA. Preoperative muscle composition of the glutei medius and minimus (Gmed+min) and the gluteus maximus (Gmax) was evaluated on a single axial computed tomography slice at the bottom end of the sacroiliac joint. Cross-sectional area ratio of individual composition to the total muscle was calculated. Result. The females (n=45) showed smaller total cross-sectional areas of the gluteal muscles than the males (n=13). Gmax in the females showed lower lean muscle mass area (LMM) and higher ratios of the intramuscular fat area and the intramuscular adipose tissue area to the total muscle area (TM) than that in the males. Regression analysis revealed that LMM/TM of Gmed+min may correlate negatively with postoperative improvement in gait speed. Receiver operating characteristic curve analysis for prediction of MCII in gait speed at ≥ 0.32 m/sec resulted in the highest area under the curve for Gmax TM with negative correlation. The explanatory variables of hip abductor muscle composition predicted gait speed improvement after THA more precisely in the females compared with the total group of both sexes. Conclusion. Preoperative Gmax TM could predict gait speed MCII after THA. Preoperative muscle composition should be evaluated separately based on sexes for achievement of clinically important improvement in gait speed after THA

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

The gait pattern of five amputees was recorded by visual observation and also by a quantitative measurement system. The results were compared with the gait pattern predicted from biomechanical analysis. Visual observation was found to be an unreliable clinical skill. The observers recorded only 22.2% of the predicted gait deviations and were unable to comment on 15.6% of all the required observations. The gait parameters which were difficult to assess visually, namely step length and step time, are considered by most workers to be of particular value as diagnostic clinical indicators in gait assessment. The measurement system used was accurate in recording gait deviations and picked up 3.4 times as many deviations as visual observation. This report demonstrates the inadequacy of visual observation as a diagnostic method and emphasises the need for measurements

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

Aims. Total knee arthroplasty (TKA) may provoke ankle symptoms. The aim of this study was to validate the impact of the preoperative mechanical tibiofemoral angle (mTFA), the talar tilt (TT) on ankle symptoms after TKA, and assess changes in the range of motion (ROM) of the subtalar joint, foot posture, and ankle laxity. Methods. Patients who underwent TKA from September 2020 to September 2021 were prospectively included. Inclusion criteria were primary end-stage osteoarthritis (Kellgren-Lawrence stage IV) of the knee. Exclusion criteria were missed follow-up visit, post-traumatic pathologies of the foot, and neurological disorders. Radiological angles measured included the mTFA, hindfoot alignment view angle, and TT. The Foot Function Index (FFI) score was assessed. Gait analyses were conducted to measure mediolateral changes of the gait line and ankle laxity was tested using an ankle arthrometer. All parameters were acquired one week pre- and three months postoperatively. Results. A total of 69 patients (varus n = 45; valgus n = 24) underwent TKA and completed the postoperative follow-up visit. Of these, 16 patients (23.2%) reported the onset or progression of ankle symptoms. Varus patients with increased ankle symptoms after TKA had a significantly higher pre- and postoperative TT. Valgus patients with ankle symptoms after TKA showed a pathologically lateralized gait line which could not be corrected through TKA. Patients who reported increased ankle pain neither had a decreased ROM of the subtalar joint nor increased ankle laxity following TKA. The preoperative mTFA did not correlate with the postoperative FFI (r = 0.037; p = 0.759). Conclusion. Approximately one-quarter of the patients developed ankle pain after TKA. If patients complain about ankle symptoms after TKA, standing radiographs of the ankle and a gait analysis could help in detecting a malaligned TT or a pathological gait. Cite this article: Bone Joint J 2023;105-B(11):1159–1167

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. Knee osteoarthritis often causes malalignment and altering bone load. This malalignment is corrected during total knee arthroplasty surgery, balancing the ligaments. Nonetheless, preoperative gait patterns may influence postoperative prosthesis load and bone support. Thus, the purpose is to investigate the impact of preoperative gait patterns on postoperative femoral and tibial component migration in total knee arthroplasty. Method. In a prospective cohort study, 66 patients with primary knee osteoarthritis undergoing cemented Persona total knee arthroplasty were assessed. Preoperative knee kinematics was analyzed through dynamic radiostereometry and motion capture, categorizing patients into four homogeneous gait patterns. The four subgroups were labeled as the flexion group (n=20), the abduction (valgus) group (n=17), the anterior drawer group (n=10), and the tibial external rotation group (n=19). The femoral and tibial component migration was measured using static radiostereometry taken supine on the postoperative day (baseline) and 3-, 12-, and 24- months after surgery. Migration was evaluated as maximum total point motion. Result. Of the preoperatively defined four subgroups, the abduction group with a valgus-characterized gait pattern exhibited the highest migration for both the femoral (1.64 mm (CI95% 1.25; 2.03)) and tibial (1.21 mm (CI95% 0.89; 1.53)) components at 24-month follow-up. For the femoral components, the abduction group migrated 0.6 mm (CI95% 0.08; 1.12) more than the external rotation group at 24 months. For the tibial components, the abduction group migrated 0.43 mm (CI95% 0.16; 0.70) more than the external rotation group at 3 months. Furthermore, at 12- and 24-months follow-up the abduction group migrated 0.39 mm (95%CI 0.04; 0.73) and 0.45 mm (95%CI 0.01; 0.89) more than the flexion group, respectively. Conclusion. A preoperative valgus-characterized gait pattern seems to increase femoral and tibial component migration until 2 years of follow-up. This suggests that the implant fixation depends on load distributions originating from specific preoperative gait patterns

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