Mid-term functional outcome of a total arthroplasty of the first metatarsophalangeal joint

Arthroplasty of the first metatarsophalangeal joint is an alternative treatment option for end-stage hallux rigidus to the current gold standard of arthrodesis. The aim of this study was to investigate the mid-term functional outcome of an anatomically shaped prosthesis for the first metatarsophalangeal joint using pedobarography.; Ten patients (12 affected feet; age at surgery: 62.1 (SD: 7.2) years) were investigated preoperatively and 52 (SD: 3) months postoperatively using pedobarography (EMED, novel GmbH, Munich, Germany). Two patients were excluded at follow-up because their prosthesis was converted to an arthrodesis. Peak force and plantar pressure under the five metatarsal heads and the hallux were analyzed and correlated with the clinical outcome (pain, American Orthopaedic Foot and Ankle Society forefoot score and radiographic maximum first metatarsophalangeal dorsiflexion). Differences between pre- and postoperative data were analyzed using paired t-tests (alpha=0.05).; Postoperatively, forefoot peak forces under the fourth (+40.9%; P=0.018) and fifth metatarsal (+54.9%; P=0.037) and plantar pressures under the fifth metatarsal (+38.7%; P=0.027) increased significantly, while peak plantar pressures and forces under the hindfoot, medial forefoot and hallux did not change. While maximum passive dorsiflexion was not significantly greater at the 4-year follow-up compared to preoperatively, overall greater passive dorsiflexion was associated with higher first metatarsal peak pressure.; Despite of patients reporting less pain, the functional results indicate an altered and potentially non-physiological postoperative gait pattern with a lateralization of the load during walking, especially in patients with limited passive dorsiflexion

Measuring joint kinematics of treadmill walking and running: Comparison between an inertial sensor based system and a camera-based system

Inertial sensor systems are becoming increasingly popular for gait analysis because their use is simple and time efficient. This study aimed to compare joint kinematics measured by the inertial sensor system RehaGait® with those of an optoelectronic system (Vicon®) for treadmill walking and running. Additionally, the test re-test repeatability of kinematic waveforms and discrete parameters for the RehaGait® was investigated. Twenty healthy runners participated in this study. Inertial sensors and reflective markers (PlugIn Gait) were attached according to respective guidelines. The two systems were started manually at the same time. Twenty consecutive strides for walking and running were recorded and each software calculated sagittal plane ankle, knee and hip kinematics. Measurements were repeated after 20min. Ensemble means were analyzed calculating coefficients of multiple correlation for waveforms and root mean square errors (RMSE) for waveforms and discrete parameters. After correcting the offset between waveforms, the two systems/models showed good agreement with coefficients of multiple correlation above 0.950 for walking and running. RMSE of the waveforms were below 5° for walking and below 8° for running. RMSE for ranges of motion were between 4° and 9° for walking and running. Repeatability analysis of waveforms showed very good to excellent coefficients of multiple correlation (>0.937) and RMSE of 3° for walking and 3-7° for running. These results indicate that in healthy subjects sagittal plane joint kinematics measured with the RehaGait® are comparable to those using a Vicon® system/model and that the measured kinematics have a good repeatability, especially for walking

Reduction in ulnar pressure distribution when walking with forearm crutches with a novel cuff design: Cross-sectional intervention study on the biomechanical efficacy of an ulnar recess

Walking with crutches is an effective way of reducing the load on the lower extremity and is often indicated after injury or surgery. However, walking with forearm crutches with conventional cuffs can trigger symptoms including tenosynovitis in the biceps tendon, ulnar neuropraxia at the wrist, pain, or skin hematoma. The purpose of this study was to test the hypothesis that a crutch cuff design with an ulnar recess reduces ulnar pressure during walking with forearm crutches. The pressure distribution between the forearm and crutch cuff was measured in 15 healthy participants for crutch walking with conventional and novel cuffs, respectively. Relative peak pressure in the proximal medial region compared to the overall peak pressure was reduced by 8.6% when walking with crutches with the novel cuff design compared to conventional cuffs (p < 0.001). Relative peak pressure in the distal intermediate and lateral regions were increased by 3.3% and 3.7% for the novel compared with conventional cuffs, respectively (p < 0.001 for both). Hence, the novel crutch cuffs shifted regions of high pressure away from the proximal ulnar region towards more distal regions that are covered by more soft tissue

Validity and reliability of a portable gait analysis system for measuring spatiotemporal gait characteristics: comparison to an instrumented treadmill

Gait analysis serves as an important tool for clinicians and other health professionals to assess gait patterns related to functional limitations due to neurological or orthopedic conditions. The purpose of this study was to assess the validity of a body-worn inertial sensor system (RehaGait®) for measuring spatiotemporal gait characteristics compared to a stationary treadmill (Zebris) and the reliability of both systems at different walking speeds and slopes.; Gait analysis was performed during treadmill walking at different speeds (habitual walking speed (normal speed); 15 % above normal walking speed; 15 % below normal walking speed) and slopes (0 % slope; 15 % slope) in 22 healthy participants twice 1 week apart. Walking speed, stride length, cadence and stride time were computed from the inertial sensor system and the stationary treadmill and compared using repeated measures analysis of variance. Effect sizes of differences between systems were assessed using Cohen's d, and limits of agreement and systematic bias were computed.; The RehaGait® system slightly overestimated stride length (+2.7 %) and stride time (+0.8 %) and underestimate cadence (-1.5 %) with small effect sizes for all speeds and slopes (Cohen's d ≤ 0.44) except slow speed at 15 % slope (Cohen's d > 0.80). Walking speed obtained with the RehaGait® system closely matched the speed set on the treadmill tachometer. Intraclass correlation coefficients (ICC) were excellent for speed, cadence and stride time and for stride length at normal and fast speed at 0 % slope (ICC: .91-1.00). Good ICC values were found for stride length at slow speed at 0 % slope and all speeds at 15 % slope (ICC: .73-.90). Both devices had excellent reliability for most gait characteristics (ICC: .91-1.00) except good reliability for the RehaGait® for stride length at normal and fast speed at 0 % slope and at slow speed at 15 % slope (ICC: .80-.87).; Larger limits of agreement for walking at 15 % slope suggests that uphill walking may influence the reliability of the RehaGait® system. The RehaGait® is a valid and reliable tool for measuring spatiotemporal gait characteristics during level and inclined treadmill walking

The effect of different running shoes on treadmill running mechanics and muscle activity assessed using statistical parametric mapping (SPM)

Differences in joint mechanics between running shoes are commonly assessed using discrete parameters, yet statistically significant differences in these parameters between shoes are often scarce with small effect sizes. Statistical parametric mapping (SPM) has been suggested as suitable method for analyzing one-dimensional data such as kinematic, kinetic or muscle intensity time series.; The purpose of this study was to determine differences in treadmill running mechanics between novel running shoes using SPM.; Joint kinematics, muscle activity and ground reaction force were assessed in 19 rearfoot runners in their own shoes and in two test shoes during treadmill running (test shoe 1: 13 distinct rubber elements in the outer sole, springboard within EVA midsole with posterior elements shifted anteriorly by approximately 1.5 cm; test shoe 2: 17 distinct EVA elements with conventional heel geometry). Joint kinematics were measured using an inertial sensor system, and ground reaction force was measured using an instrumented treadmill.; SPM analysis with repeated measures ANOVA revealed significant reductions in the ankle angle and in tibialis anterior, peroneus longus, vastus medialis and lateralis muscle activity during weight acceptance and in peroneus longus muscle activity during early and late swing and in semitendinosus muscle activity during late swing for the test shoes. Significant differences in muscle activity were observed in the interval of the main activity of the respective muscle. SPM on individual data revealed statistically significant and relevant within-subject differences between conditions in kinematic, muscle activity and ground reaction force patterns.; Inertial sensor systems and SPM may provide an efficient way of detecting changes in joint mechanics between running shoes within runners. Detecting within-subject differences in running mechanics between conditions not only requires statistical criteria but also criteria on the relevance of the magnitude of differences

Assessing in vivo articular cartilage mechanosensitivity as outcome of high tibial osteotomy in patients with medial compartment osteoarthritis: experimental protocol

Objective To propose an experimental protocol for using high tibial osteotomy (HTO) as a model for studying in vivo biological effects of large permanent changes in ambulatory load. Design This study is a prospective multimodal (clinical, biomechanical, biological) data collection without randomization. The study will examine a cohort of 40 patients with medial compartment knee OA undergoing opening wedge HTO. Experimental protocol Before planned HTO, patients will be clinically assessed (including mechanical axis measurement from radiographs) and complete questionnaires on physical function. Patients will complete a walking stress test with blood sampling (30 min walking, 5.5 h sitting), and undergo gait analysis. Six weeks after HTO (at the time of full weight bearing), the mechanical axis will be measured from radiographs. Patients will complete the questionnaires and a walking stress test with blood sampling, and undergo gait analysis 6 months after HTO. The peak external knee adduction moment, knee external knee adduction moment impulse and peak external knee flexion moment will be used as surrogates of ambulatory load. Load-induced changes in cartilage biomarkers will be used as surrogates of metabolic changes in response to ambulatory load. At the 12-month follow-up, subjects will complete the questionnaires. Conclusion The results of this study can be considered as proof-of-concept of a potential diagnostic test (walking stress test) for cartilage degeneration and its prognostic value. A direct relationship between ambulatory load and cartilage metabolism assessed as degradation to synthesis ratio would allow developing novel load-modifying interventions and evaluating the efficacy of existing interventions

Framework for modulating ambulatory load in the context of in vivo mechanosensitivity of articular cartilage

Objective: Different stress modalities have been used to provoke a load induced mechanoresponse in blood markers of articular cartilages. The challenge in in vivo experiments is to alter specific loading characteristics. Here, we aimed to develop a load modification framework that changes ambulatory load magnitude without changing load frequency or joint kinematics. Design: Spatiotemporal parameters, sagittal joint kinematics and vertical ground reaction force (vGRF) of 24 healthy participants were recorded while walking with reduced (80%), normal (100%) and increased (120%) bodyweight (BW) on three separate test days in a block randomized cross-over design. The reduced and increased load conditions were compared to the normal load condition using paired sample t-tests for spatiotemporal pa- rameters and statistical parametric mapping for vGRF and joint kinematics. Results: Load modification resulted in measured vGRF differences of 19.5%BW (reduced) and þ16.8%BW (increased). Spatiotemporal parameters with reduced and increased load did not differ from normal load except of a shorter stance time under reduced load (21 ms). Joint kinematics for both conditions did not differ from normal load except of decreased ankle dorsiflexion (maximum 5.9) and increased knee flexion (maximum þ6.5) for the reduced load condition during pre-swing when the support limb is already unloaded. Conclusion: Overall, we did not observe relevant differences in spatiotemporal parameters or joint kinematics between loading conditions. Mean absolute joint angle deviations below 4.1 demonstrate that the proposed load modification framework changes ambulatory load magnitude without changing load frequency or joint kinematics

Hip abductor muscle strength in patients after total or unicompartmental knee arthroplasty for knee osteoarthritis or avascular necrosis: a systematic review and meta-analysis protocol

Reduced hip abductor strength may indirectly lead to changes in knee kinematics and functional impairment and has been reported in patients with patellofemoral pain and knee osteoarthritis (OA). Limited information is available regarding hip abductor strength following total or unicompartmental knee arthroplasty (TKA/UKA). The aims of this systematic review are to synthesise the evidence of hip abductor muscle strength deficits in patients following TKA/UKA and to determine influencing factors for these deficits.; Embase, Medline, SportDiscus, the Web of Science Core Collection and Scopus will be searched for human-based clinical studies investigating hip abductor muscle strength after TKA/UKA for knee OA or avascular necrosis (AVN). Articles studying hip abductor strength after knee arthroplasty for post-traumatic OA will not be considered. No restriction on study design, prosthesis design, surgical approach, patient characteristics or severity of OA/AVN will be applied. We will search articles published between 1 January 1990 and the date of our last search. Only articles in English or German language will be considered for inclusion. Studies reporting manually measured muscle strength or measurements performed at hip abduction angles other than 0° will be excluded. References will be screened by two reviewers independently. Where necessary, a third author will make the final decision. The assessment of quality and risk of bias will be performed with the modified Newcastle-Ottawa scale. Data will be extracted and presented in a tabular form. Depending on availability, comparable subgroup and meta-analyses will be conducted. Patient characteristics such as age, sex and surgical approach or rehabilitation programme will be analysed, if sufficient data are available.; No ethics approval is required. The results will be published in a peer-reviewed journal and as conference presentation

Clinical and Biomechanical Outcomes of One-Stage Treatment of a Simultaneous Ipsilateral Patellar Tendon and ACL Tear Combined with a Tibial Plateau Fracture: A Case Study

Simultaneous ipsilateral patellar tendon (PT) and anterior cruciate ligament (ACL) tear is a rare injury. Associated meniscal and ligamentous injuries are common but frequently initially missed. In contrast, to date, there is no report of associated fractures. We report on a 40-year-old female Caucasian patient presenting with a ski injury resulting in simultaneous ipsilateral patellar tendon and ACL tear combined with a tibia plateau fracture and a medial and lateral meniscus lesion. ORIF of the tibia as well as one-stage primary reconstruction of the PT and ACL and suturing of the menisci was conducted. The final follow-up was 2 years postoperatively. Lower extremity kinematic, kinetic, and muscle activity measurements were conducted. Although the clinical result was excellent, altered joint kinematics went along with large side-to-side difference in hip and knee joint moments during midstance and terminal stance. During weight acceptance, vastus medialis and hamstring muscles showed greater relative activity in the injured than the uninjured side. This case demonstrates the possibility of excellent early and midterm results with a one-stage approach and suitable rehabilitation scheme. Biomechanical measurements could further help evaluate the outcome of the treatments and implications for the development of potential secondary damage

Changes in Cartilage Biomarker Levels During a Transcontinental Multistage Footrace Over 4486 km

Cartilage turnover and load-induced tissue changes are frequently assessed by quantifying concentrations of cartilage biomarkers in serum. To date, information on the effects of ultramarathon running on articular cartilage is scarce.; Serum concentrations of cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP)-1, MMP-3, MMP-9, COL2-3/4C long mono (C2C), procollagen type II C-terminal propeptide (CPII), and C2C:CPII will increase throughout a multistage ultramarathon.; Descriptive laboratory study.; Blood samples were collected from 36 runners (4 female; mean age, 49.0 ± 10.7 years; mean body mass index, 23.1 ± 2.3 kg/m2 [start] and 21.4 ± 1.9 kg/m2 [finish]) before (t0) and during (t1: 1002 km; t2: 2132 km; t3: 3234 km; t4: 4039 km) a 4486-km multistage ultramarathon. Serum COMP, MMP-1, MMP-3, MMP-9, C2C, and CPII levels were assessed using commercial enzyme-linked immunosorbent assays. Linear mixed models were used to detect significant changes in serum biomarker levels over time with the time-varying covariates of body weight, running speed, and daily running time.; Serum concentrations of COMP, MMP-9, and MMP-3 changed significantly throughout the multistage ultramarathon. On average, concentrations increased during the first measurement interval (MI1: t1-t0) by 22.5% for COMP (95% CI, 0.29-0.71 ng/mL), 22.3% for MMP-3 (95% CI, 0.24-15.37 ng/mL), and 95.6% for MMP-9 (95% CI, 81.7-414.5 ng/mL) and remained stable throughout MI2, MI3, and MI4. Serum concentrations of MMP-1, C2C, CPII, and C2C:CPII did not change significantly throughout the multistage ultramarathon. Changes in MMP-3 were statistically associated with changes in COMP throughout the ultramarathon race (MMP-3: Wald Z = 3.476, P = .001).; Elevated COMP levels indicate increased COMP turnover in response to extreme running, and the association between load-induced changes in MMP-3 and changes in COMP suggests the possibility that MMP-3 may be involved in the degradation of COMP.; These results suggest that articular cartilage is able to adapt even to extreme physical activity, possibly explaining why the risk of degenerative joint disease is not elevated in the running population