Arthroscopic synovectomy in the treatment of functional ankle instability: outcomes and gait analysis.

BACKGROUND: Natural consequence of repetitive ankle sprains is the chronic ankle instability. Objective of this study was to clarify the gait patterns of functional ankle instability (FAI) patients after arthroscopic synovectomy, but also assessment of postoperative recovery. PATIENTS AND METHODS: Arthroscopic synovectomy was performed to 14 FAI patients with history of unilateral repetitive ankle sprains, pain, and subjective sensation of instability. At a mean 54 months of follow-up (27-84), clinical assessment was conducted with respect to pain, number of ankle sprains, and American Orthopaedics Foot and Ankle Society (AOFAS) scores. Gait analysis was conducted to determine the temporospatial, kinetic and kinematic parameters at the last follow-up. RESULTS: Mean AOFAS scores increased from 68 (range 55-75) to 89 (range 77-100) points (P < 0.01). Mean ankle sprains was 13 in a period of 23 (range 14-48) months (0.58 per month) and decreased to three sprains in a mean time period of 54 months (0.053 per month) (P < 0.01). Mean preoperative and postoperative VAS scores were 8.0 and 2.9, respectively (P < 0.01). During gait analysis, no significant differences were found in ankle joint, including foot progression angles, ankle dorsi-plantar flexion degrees and ground reaction forces (P > 0.01). Among temporospatial parameters, only double support time showed a significant difference (P < 0.01). All patients were satisfied from the procedure and returned to their previous activity level. CONCLUSION: Improved long-term clinical results and scores were obtained in our patient group when compared with the preoperative scores. Also, three-dimensional gait analysis showed that the involved ankles demonstrate similar gait patterns to the uninvolved ankles in patients with FAI.

Suture anchor tenodesis in repair of distal Achilles tendon injuries.

BACKGROUND: Distal Achilles tendon avulsions are in the form of either bony and nonbony avulsion of Achilles tendon from its calcaneal insertion. METHODS: Four patients with distal Achilles tendon avulsions or ruptures which were treated with tendon to bone repair using suture anchors are presented here. Operated leg was immobilized in above-knee cast for 4 weeks while the patient walked non-weight-bearing. Then, cast was changed to below knee, and full weight-bearing was allowed. Patients underwent gait analysis minimum at first postoperative year. RESULTS: Mean American Orthopedics Foot Ankle Society ankle/hindfoot score of patients at last visit was 88.75 (range 85-100), and Achilles tendon total rupture score was 77.75 (range 58-87). Mean passive dorsiflexion of injured ankles (14° ± 5°) was lower than uninjured ankles (23° ± 9°). All the kinematic parameters of gait analysis were comparable to the uninjured side. Maximum plantar flexion power of injured ankle was 1.40 W/kg, and this was significantly lower than the contralateral side value 2.38 W/kg; (P = 0.0143). CONCLUSIONS: There were no visually altered gait or problems in daily life. Suture anchor tenodesis technique of distal Achilles tendon avulsions was successful in achieving durable osteotendinous repairs.

Functional Bandaging in Children with Idiopathic Toe-Walking.

BACKGROUND: Idiopathic toe-walking (ITW) is a persistent gait pattern with no known etiology characterized as premature heel rise or no heel contact. We investigated the effects of functional bandaging in children with ITW on heel contact during stance phase and on gait quality. METHODS: Nineteen children aged 4 to 16 years with ITW and ten age-matched healthy children were included in the study. Elastic adhesive bandages were applied to children with ITW to assist with dorsiflexion. Before bandaging (T0) and immediately (T1) and 1 week (T2) after initial bandaging, the initial contact, loading response, and midstance subphases of gait were analyzed using light pressure sensors and the Edinburgh Visual Gait Score (EVGS). Ten age-matched children with typical gait participated for comparison in T0. The data were analyzed with Friedman and Wilcoxon signed rank tests for within-group comparisons and Mann-Whitney U tests for between-group comparisons. RESULTS: In T0, for the ITW group, no heel contact was observed during stance. In T1, all of the participants achieved heel contact at initial contact and loading response and 56.8% at midstance. In T2, all of the heels continued contact at initial contact and loading response and 54.3% at midstance. The EVGS significantly improved. The Friedman test showed that there were noteworthy improvements between T0-T1 and T0-T2 in video-based observational gait analysis and EVGSs (P < .001), although no difference was found between T1-T2 in video-based observational gait analysis (P = .913) and EVGSs (P = .450). CONCLUSIONS: In children with ITW, dorsiflexion assistive functional bandaging was an effective tool to help achieve heel contact on the ground and improve walking quality for a short period after application. Further studies with longer follow-up and larger sample sizes are required to confirm the long-term therapeutic effects of this promising functional bandaging.

Relationship Between Recurrent Adductus Deformity of the Forefoot and Achilles Tendon Elongation Following Ponseti Treatment in Children with Idiopathic Clubfoot.

BACKGROUND: Many authors have highlighted the role of muscle strength imbalance around the ankle in the development of recurrent clubfoot following Ponseti treatment. However, this possible underlying mechanism behind recurrence has not been investigated sufficiently to date. This study aimed to explore whether there is a relationship between Achilles tendon elongation and recurrent metatarsus adductus deformity in children with unilateral clubfeet treated by the Ponseti method. METHODS: A retrospective chart review was performed on 20 children (14 boys and six girls; mean age, 7 years; age range, 5-9 years) with a recurrent metatarsus adductus deformity treated by the Ponseti method for unilateral idiopathic clubfoot. At the final follow-up, isometric muscle strength was measured using a portable, hand-held dynamometer in reciprocal muscle groups of the ankle. The length of the tendons around the ankle was measured ultrasonographically. RESULTS: The plantarflexion-to-dorsiflexion ratio was lower on the involved side (P = .001). No significant differences in the strength ratio of inversion to eversion were found (P = .4). No difference was observed in lengths of tibialis anterior and posterior tendons (P = .1), but the Achilles tendon was longer on the involved side (P = .001; P < .01). A significant negative correlation was discovered between involved-to-uninvolved Achilles tendon length ratios and involved-to-uninvolved plantarflexion strength ratios (r = -0.524; P = .02) Conclusions: Achilles tendon elongation may be a contributor to the muscle imbalance in clubfeet with relapsed forefoot adduction treated by the Ponseti technique.

Functional Bandaging in Children with Idiopathic Toe Walking.

BACKGROUND: Idiopathic toe walking (ITW) is a persistent gait pattern with no known etiology, which is characterized as premature heel-rise or no-heel contact. The aim of this study was to investigate the effects of functional bandaging in children with ITW on heel-contact during stance phase and gait quality. METHODS: Nineteen children, 4-16 years of age with ITW (mean{plus minus}SD: 7.36{plus minus}3.16) and ten age-matched healthy pairs (mean{plus minus}SD: 7.30{plus minus}2) were included in the study. Elastic adhesive bandages were applied to children with ITW to assist with dorsiflexion. Before bandaging (T0), immediately after initial bandaging (T1), and one week later with the same bandage (T2), the initial contact, loading response, and mid-stance sub-phases of gait were analyzed using light-pressure sensors and the Edinburgh Visual Gait Score (EVGS). Ten age-matched children with typical gait participated for comparison in T0. The data was analyzed by using Friedman and Wilcoxon signed-rank tests for within-group comparison and Mann-Whitney U tests for between-group comparison. RESULTS: In T0, for the ITW group, no heel contact was observed during stance. In T1, all the participants achieved heel contact at initial contact and loading response; and 56.8%, at mid-stance. In T2, all the heels continued contact at initial contact and loading response; and 54.3%, at mid-stance. The EVGS significantly improved. The Friedman test showed that there were noteworthy improvements between T0-T1 and T0-T2 in VBOGA and EVGS (p < 0.001), although no difference was found between T1-T2 in VBOGA (p = 0,913) and EVGS (p = 0,450). CONCLUSIONS: In this study, for ITW children, dorsiflexion assistive functional bandaging was an effective tool to help achieving heel contact on the ground and improve walking quality for a short period of time after the application. Further studies with longer follow-ups and larger sample sizes are required to confirm the long duration therapeutic effects of this promising functional bandaging.

Effect of balneotherapy on temporospatial gait characteristics of patients with osteoarthritis of the knee.

Effects of balneotherapy on gait properties of patients with osteoarthritis of the knee were investigated prospectively. A total of 30 patients with knee osteoarthritis received balneotherapy consisting of two daily thermomineral water baths for 2 weeks. Patients were evaluated using gait analysis and clinical scores, both within 2 weeks, before and after spa treatment. Patients were walking faster in their control analyses (0.81 +/- 0.21 to 0.89 +/- 0.19 m/s; P = 0.017), with a shorter mean stance time (63.0 +/- 3.3 to 61.8 +/- 2.5% stride; P = 0.007), an increased cadence (96 +/- 13.1 to 100 +/- 11.9 steps/min; P = 0.094) and stride length (996 +/- 174 to 1,058 +/- 142 mm; P = 0.017). Balneotherapy also resulted in a significant decrease in Lequesne knee osteoarthritis index (12.1 +/- 3.7 to 10.0 +/- 3.3 points; P = 0.003), VAS for pain (58 +/- 25 to 33 +/- 15; P = 0.0001), VAS for patients' (56 +/- 24 to 29 +/- 19; P < 0.001) and investigator's global assessment (55 +/- 20 to 26 +/- 15; P < 0.0001) and WOMAC score (2.1 +/- 0.7 to 1.6 +/- 0.8; P = 0.0004). Balneotherapy has positive effects on gait properties and clinical health quality parameters of patients with knee osteoarthritis in short-term evaluations.

[Treatment approaches to flexion contractures of the knee]. / Diz fleksiyon kontraktüründe tedavi yaklasimlari.

The knee is the most affected joint in children with cerebral palsy. Flexion contracture of the knee is the cause of crouch gait pattern, instability in stance phase of gait, and difficulties during standing and sitting, and for daily living activities. It may also cause patella alta, degeneration of the patellofemoral joint, and stress fractures of the patella and tibial tubercle in young adults. Children with cerebral palsy may even give up walking due to its high energy demand in the adult period. The purpose of this article is to review the causes of the knee flexion contractures, clinical and radiological evaluations, and treatment principles in children with cerebral palsy. The biomechanical reasons of knee flexion deformity are discussed in detail in the light of previous studies and gait analysis data.

Intraoperative experiments combined with gait analyses indicate that active state rather than passive dominates the spastic gracilis muscle's joint movement limiting effect in cerebral palsy.

BACKGROUND: In cerebral palsy, spastic muscle's passive forces are considered to be high but have not been assessed directly. Although activated spastic muscle's force-joint angle relations were studied, this was independent of gait relevant joint positions. The aim was to test the following hypotheses intraoperatively: (i) spastic gracilis passive forces are high even in flexed knee positions, (ii) its active state forces attain high amplitudes within the gait relevant knee angle range, and (iii) increase with added activations of other muscles. METHODS: Isometric forces (seven children with cerebral palsy, gross motor function classification score = II) were measured during surgery from knee flexion to full extension, at hip angles of 45° and 20° and in four conditions: (I) passive state, after gracilis was stimulated (II) alone, (III) simultaneously with its synergists, and (IV) also with an antagonist. FINDINGS: Directly measured peak passive force of spastic gracilis was only a certain fraction of the peak active state forces (maximally 26%) measured in condition II. Conditions III and IV caused gracilis forces to increase (for hip angle = 45°, by 32.8% and 71.9%, and for hip angle = 20°, by 24.5% and 45.1%, respectively). Gait analyses indicated that intraoperative data for knee angles 61-17° and 33-0° (for hip angles 45° and 20°, respectively) are particularly relevant, where active state force approximates its peak values. INTERPRETATION: Active state muscular mechanics, rather than passive, of spastic gracilis present a capacity to limit joint movement. The findings can be highly relevant for diagnosis and orthopaedic surgery in individuals with cerebral palsy.

Gait Analysis of Patients Subjected to the Atrophic Mandible Augmentation with Iliac Bone Graft.

In this study, we aimed to quantitatively monitor and describe the gait functions of patients, who underwent iliac crest bone grafting in atrophic jaw augmentation operation, by taking into account the alterations of gait parameters and muscle forces in the early recovery course. To do so, temporospatial and kinematic gait parameters of ten patients during pre- and postoperative periods were recorded, and forces of the gluteus medius, gluteus maximus, and iliacus muscles were calculated. Three postoperative periods were specified as one week (post-op1), two weeks (post-op2), and three weeks (post-op3) after the surgery. Restoring process of the gait patterns was comparatively evaluated by analyzing the gait parameters and muscle forces for pre- and postoperative periods. Temporospatial and kinematic parameters of post-op3 were closer to those obtained in pre-op than those in post-op1 and post-op2 (p < 0.05). Muscle forces calculated in post-op3 showed the best agreement with those in pre-op among the postoperative periods in terms of both magnitude and correlation (p < 0.05). In conclusion, the patients began to regain their preoperative gait characteristics from the second week after surgery, but complete recovery in gait was observed three weeks after the surgery.

Increased femoral anteversion-related biomechanical abnormalities: lower extremity function, falling frequencies, and fatigue.

BACKGROUND: Increased femoral anteversion (IFA) is defined as forwardly rotated femoral head relative to the transcondylar knee axis which may have a potential to reduce the functional quality of adolescents. Therefore, the aim of our study was to investigate the effects of IFA on lower-extremity function, falling frequency, and fatigue onset in neurologically intact children. RESEARCH QUESTION: Does increased femoral anteversion influence lower extremity function, falling frequency and fatigue on set in healthy children? METHODS: Sixty-five participants with increased femoral anteversion (IFA) and thirty-two healthy peers as control were included into the study. For the function, the lower extremity function form (LEFF) which is adapted from Lower Extremity Function Test used. Falling frequency and fatigue onset time were assessed by a Likert-type scale. In addition, the activities which cause frequently fall for the participants were questioned. RESULTS: Lower extremity function was found deteriorated (p= 0.02) and falling frequency was higher (p = 0.00) in IFA than in controls. Fatigue onset time was not different between groups, although lower extremity function was strongly correlated with fatigue onset (rho = -0.537, p < 0.001). IFA children fall four times more during running (60%), three times more during fast walking (21.42%) than their healthy peers (14.28%, 7.14% respectively). SIGNIFICANCE: IFA leads functional problems, especially in the form of high falling frequencies. According to the LEFF score, the most difficult functional parameters for these children were walking long distances, becoming tired, walking more than a mile, and standing on one spot. Also, shorter fatigue onset time may worsen the lower-extremity function secondarily. Because of the higher frequency of falling and functional problems, children with IFA may be more defenseless to injuries, especially in high-motor-skill activities such as running and soccer.

Effects of antagonistic and synergistic muscles' co-activation on mechanics of activated spastic semitendinosus in children with cerebral palsy.

OBJECTIVES: Most activities involve co-activation of several muscles and epimuscular myofascial force transmission (EMFT) can affect their mechanics. This can be relevant for spastic muscles of cerebral palsy (CP) patients. Isometric spastic semitendinosus (ST) forces vs. knee angle (KA-FST) data were collected intra-operatively to test the following hypotheses: (i) Inter-antagonistic EMFT elevates FST, (ii) changes the shape of KA-FST characteristics, (iii) reduces the muscle's joint range of force exertion (Range-FST) and (iv) combined inter-antagonistic and synergistic EMFT further changes those effects. METHODS: 11 limbs of 6 patients with CP (mean (SD) = 7.7 (4.7) years; GMFCS levels = II-IV) were tested in 3 conditions from 120° to full extension: ST activated (I) exclusively, (II) simultaneously with an antagonist, and (III) with added activation of synergists. RESULTS: Condition II increased FST (e.g., peak force = 87.6 N (30.5 N)) significantly (by 33.6%), but condition III caused no further change. No condition changed the muscle's wide Range-FST (100.7° (15.9°)) significantly. Therefore, only the first hypothesis was confirmed. CONCLUSIONS: Co-activating its antagonist elevates forces of activated spastic ST substantially, but does not change its joint range of force exertion. Added activation of its synergists causes no further effects. Therefore, EMFT effects in CP can be relevant and need to be tested in other knee flexors.

Does clinically measured ankle plantar flexor muscle strength or weakness correlate with walking performance in healthy individuals?

OBJECTIVE: Muscle strength is usually measured using isometric hand-held dynamometers (HHDs) in the clinic. However, during functional activities, the muscle acts more dynamically. The aim of this study was to investigate the relation between clinically measured plantar flexor (PF) muscle strength (PFMS) and laboratory measurements of peak ankle plantar flexion power generation (APFPG), peak ankle moment (PAM), peak plantar flexion velocity (PFV) and mean gait velocity in healthy participants. METHODS: The maximum PFMS on non-dominant sides in 18 able-bodied persons 23.88 (SD 3.55 years) was measured before (Pre-S) and after a stretching (Post-S) procedure (135 sec. × 13 rep. with 5 sec. rest) by using a HHD. The stretching procedure was used to generate temporary PF muscle weakness. Gait analysis was carried out for Pre-S and Post-S conditions. Normalized (by weight and height) and non-normalized HHD scores and differences for both conditions were correlated by Pearson correlation coefficient calculations (p< 0.05). RESULTS: Reduced PFMS (%23, p< 0.001) in Post-S, according to the HHD scores, has only a weak correlation with APFPG (r> 0.3, p< 0.5). Gait velocity was found to be strongly correlated with APFPG only in the Post-S condition (r= 0.68, p< 0.002). HHD scores and PAM were moderately correlated with the non-normalized Post-S condition (r= 0.44, p= 0.70) and strongly correlated with the non-normalized Pre-S condition (r= 0.62, p< 0.01). DISCUSSION: HHD scores of plantar flexor muscles give very limited information about the PF performance during walking in healthy individuals. Simple normalization did not improve the relations. Clinically measured isometric muscle strength and muscle weakness have only moderate strengths for establishing a treatment protocol and for predicting performance during walking in neurologically intact individuals.

Effects of inter-synergistic mechanical interactions on the mechanical behaviour of activated spastic semitendinosus muscle of patients with cerebral palsy.

Previous physiological experiments and finite element modelling indicate that inter-synergistic epimuscular myofascial force transmission (EMFT) between co-activated muscles has a potential to affect healthy muscle's contribution to joint moment and joint range of movement. This is quite relevant for patients with cerebral palsy (CP) since, amplitude of spastic muscle's force and the joint range of force exertion are central to the joint movement limitation. Stiffness of activated spastic muscle is also a determinant for pathological joint movement. However, assessments of effects of inter-synergistic EMFT on the mechanical behaviour of spastic muscle are lacking. Those assessments require measurement during surgery of activated spastic muscle's forces directly at its tendon and as a function of joint angle. Employing this methodology, the aim was to test the following study hypotheses: added activation of semimembranosus (SM) and gracilis (GRA) muscles of patients with CP changes (1) force, (2) stiffness and (3) joint range of force exertion of activated spastic semitendinosus (ST) due to inter-synergistic EMFT. Isometric spastic ST forces were measured intraoperatively (12 limbs of 7 patients (mean age 8 years 9 months) for knee angles from flexion (120°) to full extension (0°). Conditions I and II: spastic ST was activated alone, and simultaneously with its synergists SM and GRA muscles, respectively. Condition II did increase activated spastic ST's forces significantly (by 33.3%), but did not change its stiffness and joint range of force exertion, confirming only study hypothesis 1. Therefore, we conclude that inter-synergistic EMFT affects forces exerted at spastic ST tendon, but not other characteristics of its angle-force relationship.

Intra-operatively measured spastic semimembranosus forces of children with cerebral palsy.

The knee kept forcibly in a flexed position is typical in cerebral palsy. Using a benchmark, we investigate intra-operatively if peak spastic hamstring force is measured in flexed knee positions. This tests the assumed shift of optimal length due to adaptation of spastic muscle and a decreasing force trend towards extension. Previously we measured spastic gracilis (GRA) and semitendinosus (ST) forces. Presently, we studied spastic semimembranosus (SM) and tested the following hypotheses: spastic SM forces are (1) high in flexed and (2) low in extended positions. We compared the data to those of GRA and ST to test (3) if percentages of peak force produced in flexed positions are different. During muscle lengthening surgery of 8 CP patients (9years, 4months; GMFCS levels=II-IV; limbs tested=13) isometric SM forces were measured from flexion (120°) to full extension (0°). Spastic SM forces were low in flexed knee positions (only 4.2% (3.4%) and 10.7% (9.7%) of peak force at KA=120° and KA=90° respectively, indicating less force production compared to the GRA or ST) and high in extended knee positions (even 100% of peak force at KA=0°). This indicates an absence of strong evidence for a shift of optimal muscle length of SM towards flexion.

The mechanics of activated semitendinosus are not representative of the pathological knee joint condition of children with cerebral palsy.

Characteristic cerebral palsy effects in the knee include a restricted joint range of motion and forcefully kept joint in a flexed position. To show whether the mechanics of activated spastic semitendinosus muscle are contributing to these effects, we tested the hypothesis that the muscle's joint range of force exertion is narrow and force production capacity in flexed positions is high. The isometric semitendinosus forces of children with cerebral palsy (n=7, mean (SD)=7years (8months), GMFCS levels III-IV, 12 limbs tested) were measured intra-operatively as a function of knee angle, from flexion (120°) to full extension (0°). Peak force measured in the most flexed position was considered as the benchmark. However, peak force (mean (SD)=112.4N (54.3N)) was measured either at intermediate or even full knee extension (three limbs) indicating no narrow joint range of force exertion. Lack of high force production capacity in flexed knee positions (e.g., at 120° negligible or below 22% of the peak force) was shown except for one limb. Therefore, our hypothesis was rejected for a vast majority of the limbs. These findings and those reported for spastic gracilis agree, indicating that the patients' pathological joint condition must rely on a more complex mechanism than the mechanics of individual spastic muscles.

Femoral derotation osteotomy with multi-level soft tissue procedures in children with cerebral palsy: Does it improve gait quality?

PURPOSE: Poor motor control and delayed thumb function and a delay in walking are the main factors which retard the natural decrease of the femoral anteversion (FA) with age. In addition, cerebral palsy (CP) patients usually have muscular imbalance around the hip as well as muscle contractures, both of which are main factors accounting for the increased FA which is commonly present in CP patients. The purpose of this retrospective study was to analyze the mid-term results of femoral derotational osteotomy (FDO) on the clinical findings, temporospatial and kinematic parameters of gait in children with CP. METHODS: We performed a retrospective review of all patients diagnosed with CP and increased FA who were treated with FDO with multi-level soft tissue surgeries at a single institution between 1992 and 2011. FA assessment was done in the prone position, and internal (IR) and external rotation (ER) of the hip was measured in the absence of pelvis rotation. Surgical procedures were performed on the basis of both clinical findings and video analysis. Clinical findings, Edinburgh Visual Gait Scores (EVGS) and results from three-dimensional gait analysis were analyzed preoperatively and last follow-up. RESULTS: A total of 93 patients with 175 affected extremities were included in this review. Mean age was 6.2 ± 3.1 (standard deviation) at initial surgery. The average length of the follow-up period was 6.3 ± 3.7 years. At the last follow-up, the postoperative hip IR had significantly decreased (73.9° vs. 46.2°; p < 0.0001), the hip ER had significantly improved (23.8° vs. 37°; p < 0.0001) and the popliteal angle had significantly decreased (64.2° vs. 55.8°; p < 0.0001). The total EVGS showed significant improvement after FDO (35.2 ± 6.4 vs. 22.5 ± 6.1; p < 0.001). Computed gait analysis showed significant improvement in the foot progression angle (FPA; 8.1° vs. -16.9°; p = 0.005) and hip rotation (-13.9° vs. 5.7°; p = 0.01) at the last follow-up. Stance time was improved (60.2 vs. 65.1 %; p = 0.02) and swing time was decreased (39.9 vs. 35.2 %; p = 0.03). Double support time and cadence were both decreased (p = 0.032 and p = 0.01). CONCLUSIONS: Our data suggest that the FDO is an appropriate treatment strategy for the correction of FA and associated in-toeing gait in children with CP. Improvements in clinical and kinematic parameters were observed in both groups after FDO with multi-level soft tissue release. The most prominent effects of FDO were on transverse plane hip rotation and FPA.

Weakening iliopsoas muscle in healthy adults may induce stiff knee pattern.

OBJECTIVE: The goal of the present study was to investigate the relationship between iliopsoas muscle group weakness and related hip joint velocity reduction and stiff-knee gait (SKG) during walking in healthy individuals. METHODS: A load of 5% of each individual's body weight was placed on non-dominant thigh of 15 neurologically intact, able-bodied participants (average age: 22.4 ± 0.81 years). For 33 min (135 s × 13 repetitions × 5 s rest), a passive stretch (PS) was applied with the load in place until hip flexor muscle strength dropped from 5/5 to 3+/5 according to manual muscle test. All participants underwent gait analysis before and after PS to compare sagittal plane hip, knee, and ankle kinematics and kinetics and temporo-spatial parameters. Paired t-test was used to compare pre- and post-stretch findings and Pearson correlation coefficient (r) was calculated to determine strength of correlation between SKG parameters and gait parameters of interest (p < 0.05). RESULTS: Reduced hip flexion velocity (mean: 21.5%; p = 0.005) was a contributor to SKG, decreasing peak knee flexion (PKF) (-20%; p = 0.0008), total knee range (-18.9%; p = 0.003), and range of knee flexion between toe-off and PKF (-26.7%; p = 0.001), and shortening duration between toe-off to PKF (-16.3%; p = 0.0005). CONCLUSION: These findings verify that any treatment protocol that slows hip flexion during gait by weakening iliopsoas muscle may have great potential to produce SKG pattern combined with reduced gait velocity.

Contributors of stiff knee gait pattern for able bodies: Hip and knee velocity reduction and tiptoe gait.

UNLABELLED: Stiff-knee gait (SKG) is commonly encountered in clinic; many other gait abnormalities are seen together with this pathology. Simulation studies revealed that diminished knee flexion (KF) velocity and increased knee extension moments are strongly related with SKG. This study aimed to determine whether tiptoe walking and hip-knee flexion velocity reduction causes SKG pattern in healthy participants. METHODS: Fourteen able-bodied adults' (Av. age: 23.0±2.4) heel-toe (N), tiptoe (T), and walking with 5% body weight on both shanks (W) were analyzed using 3D gait analysis by controlling cadence (90step/min). Repeated measures analysis of variance was used followed by Bonferroni correction (p<0.05). RESULTS: Walking velocity and cadence were similar for all conditions (p>0.1). Maximum hip flexion velocity was reduced (15%) significantly as well as the KF velocity (10%) in the W condition. The peak knee flexion (PKF) (8.3% for T, 8.6% for W) and total knee range (10.9% for T, 13% for W) were reduced for both conditions (p<0.05). The knee range in early swing and the duration between toe-off and PKF were reduced only in the weighted-leg condition (p<0.05). CONCLUSIONS: Slow hip and knee flexion diminished all SKG parameters except timing of PKF. Tiptoe gait itself generated a borderline SKG pattern by reducing the PKF and total knee range. By considering that tiptoe gait and SKG commonly seen together, some of the SKG contributors can be treated by normalizing the ankle motion in the stance and increasing the hip-knee flexion velocity by rigorously planned muscle lengthening procedures and effective strengthening exercises.

Plantar flexor muscle weakness may cause stiff-knee gait.

AIM: The iterative simulation studies proclaim that plantar flexor (PF) muscle weakness is one of the contributors of stiff knee gait (SKG), although, whether isolated PF weakness generates SKG has not been validated in able-bodied people or individuals with neuromuscular disorders. The aim of the study was to investigate the effects of isolated PF muscle weakness on knee flexion velocity and SKG in healthy individuals. METHOD: Twenty able-bodied young adults (23±3 years) participated in this study. Passive stretch (PS) protocol was applied until the PF muscle strength dropped 33.1% according to the hand-held dynamometric measurement. Seven additional age-matched able-bodies were compared with participants' to discriminate the influence of slow-walking. All participants underwent 3D gait analysis before and after the PS. Peak knee flexion angle, range of knee flexion between toe-off and peak knee flexion, total range of knee-flexion, and time of peak knee flexion in swing were selected to describe SKG pattern. RESULTS: After PS, the reduction of plantar flexor muscle strength (33.14%) caused knee flexion velocity drop at toe-off (p=0.008) and developed SKG pattern by decreasing peak knee flexion (p=0.0001), range of knee flexion in early swing (p=0.006), and total knee flexion range (p=0.002). These parameters were significantly correlated with decreased PF velocity at toe-off (p=0.015, p=0.0001, p=0.005, respectively). The time of peak knee flexion was not significantly different between before and after stretch conditions (p=0.130). CONCLUSIONS: These findings verified that plantar flexor weakness cause SKG pattern by completing three of SKG parameters. Any treatment protocol that weakens the plantar flexor muscle might impact the SKG pattern.

Intraoperative experiments show relevance of inter-antagonistic mechanical interaction for spastic muscle's contribution to joint movement disorder.

BACKGROUND: Recent intra-operative knee angle-muscle force data showed no abnormal muscular mechanics (i.e., a narrow joint range of muscle force exertion and peak muscle force availability at flexed joint positions), if the spastic gracilis muscle was stimulated alone. This can limit inter-muscular mechanical interactions, which have been shown to affect muscular mechanics substantially. We aimed at testing the hypothesis that the knee angle-muscle force curves of the spastic gracilis muscle activated simultaneously with a knee extensor are representative of joint movement disorder. METHODS: Experiments were performed during remedial surgery of spastic cerebral palsy patients (n=6, 10 limbs tested). Condition-I: muscle forces were measured in flexed knee positions (120° and 90°) after activating the gracilis exclusively. Condition-II: knee angle-muscle force data were measured from 120° to full extension after activating the vastus medialis, simultaneously. FINDINGS: Condition-II vs. I: Inter-antagonistic interaction did not consistently cause a gracilis force increase. Condition-II: Peak muscle force=mean 47.92 N (SD 22.08 N). Seven limbs showed availability of high muscle force in flexed knee positions (with minimally 84.8% of peak force at 120°). Knee angle-muscle force curves of four of them showed a local minimum followed by an increasing force (explained by an increasing passive force, indicating muscle lengths unfavorable for active force exertion). High active gracilis forces measured at flexed knee positions and narrow operational joint range of force exertion do indicate abnormality. The remainder of the limbs showed no such abnormality. INTERPRETATION: Our hypothesis is confirmed for most, but not all limbs tested. Therefore, tested inter-antagonistic mechanical interaction can certainly, but not exclusively be a factor for abnormal mechanics of the spastic muscle.