Distribution of segmental foot kinematics in patients with degenerative joint disease of the ankle

Degenerative joint disease (DJD) of the ankle is a debilitating chronic disease associated with severe pain and dysfunction resulting in antalgic gait alteration. Little information is available about segmental foot and ankle motion distribution during gait in ankle osteoarthritis. The aim of the current study was to dynamically characterize segmental foot and ankle kinematics of patients with severe ankle arthrosis requiring total ankle replacement. This was a prospective study involving 36 (19 M, 17 F) adult patients with a clinical diagnosis of ankle arthrosis (“DJD” group) and 36 (23 M, 13 F) healthy subjects (“Control” group). Motion data were collected at 120 Hz using a 3‐D motion camera system at self‐selected speed along a 6‐m walkway and processed using the Milwaukee Foot Model (MFM). The SF‐36 Health Survey and Orthopaedic Foot and Ankle Society (AOFAS) ankle‐hindfoot scale were administered to evaluate functional levels. Findings include decreases in walking speed, cadence, stride length and swing phase, and reduced outcomes scores (SF‐36 and AOFAS). Multisegemental motion in patients with ankle DJD demonstrates significant changes in foot mechanics characterized by altered segment kinematics and significant reduction in dynamic ROM at the tibia, hindfoot, forefoot, and hallux when compared to controls. The results demonstrate decreased temporal‐spatial parameters and low outcomes scores indicative of functional limitations. Statement of clinical significance: Altered segment kinematics and reduced overall range of motion demonstrate how a single joint pathology affects kinematic distribution in the other segments of the foot and ankle and alters patients’ overall gait. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1739–1746, 2018.

     

Gait analysis related to functional outcome in patients operated for ankle fractures

Ankle fractures are among the most common lower limb fractures. Associations between postoperative radiographic results and clinical outcome have been found, but less is known about the relevant ankle biomechanics. This study analyzed ankle kinematics, radiographic findings, and patient‐reported outcome measures (PROM) in patients treated for ankle fractures. The hypothesis was that patients after ankle fracture surgery had less flexion/extension in the ankle compared to healthy subjects and that fracture severity had significant influence on kinematics and patient satisfaction. Thirty‐three patients (n = 33 feet) operated for ankle fractures were recruited. Ankle kinematics were analyzed using the Oxford Foot model, and results were compared with an age‐matched healthy control group (11 patients, 20 feet). In addition, patients were divided by fracture (severity) classification and kinematic results were correlated with PROM and radiographic findings. Patients treated for ankle fracture showed lower walking speed (p < 0.001) when asked to walk in preferred normal speed. When compared at equal speed, significantly less range of motion (ROM) between the hindfoot and tibia in the sagittal plane (flexion/extension) during loading and push‐off phases (p = 0.003 and p < 0.001) was found in patients after ankle fractures compared to healthy subjects. Lowest ROM and poorest PROM results were found for patients with trimalleolar ankle fractures. There was a significant correlation between ROM (flexion/extension) during the push‐off phase and SF‐36 physical functioning (r² = 0.403, p = 0.027) and SF‐36 general health (r² = 0.473, p = 0.008). Fracture severity was significantly correlated with flexion/extension ROM in the ankle during both loading and push‐off phases (r² = ?0.382, p = 0.005, and r² = ?0.568, p < 0.001) and was also significantly correlated with PROM. This study found that patients with ankle fractures had significantly altered ankle kinematics compared to healthy subjects. The poorest results were found among patients with trimalleolar fractures. Weak to strong significant correlations were found between fracture severity, ankle kinematics, and PROM. © 2019 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 37:1658–1666, 2019.     

Quantitative characterization of gait kinematics in patients with hallux rigidus using the Milwaukee foot model

The purpose of this study was to provide a quantitative analysis of the changes that occur in the foot and ankle during the gait of patients with hallux rigidus. Using a 15‐camera Vicon Motion Analysis System, gait analysis was conducted on a population of 22 patients with hallux rigidus and compared to that of 25 healthy ambulators. Weight‐bearing radiographs were measured to index marker positions to underlying bony anatomy. The Milwaukee Foot Model was used to perform three‐dimensional analysis of dynamic foot and ankle motion, and temporal–spatial parameters were also calculated. Values were compared to controls using unpaired parametric methods (Student t‐test, p < 0.002). The hallux rigidus population showed significant alterations in gait patterns as compared to controls in various planes in all segments (hallux, forefoot, hindfoot, and tibia) of the foot and ankle, particularly in the range of motion of the hallux and the forefoot. Prolonged stance phase was also observed. As reports regarding the quantitative study of the multisegment foot and ankle are limited, this study was useful in providing characterization of gait patterns in patients with hallux rigidus. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:419–427, 2008     

Proposed novel unified nomenclature for range of joint motion: method for measuring and recording for the ankles, feet, and toes

The Ad Hoc Committee of Terminology of the Japanese Society for Surgery of the Foot (JSSF) proposes novel terminology for motion of the ankle, foot, and toe because there are some ambiguities in the current terminology. Articles were identified by searching the electronic databases of PubMed that compared definitions of American Orthopaedic Foot and Ankle Society (AOFAS), International Society of Biomechanics (ISB), and in the textbook of Kapandji as well as the American Academy of Orthopaedic Surgeons (AAOS). A total of 11 articles described the transverse (horizontal) plane motion in the hindfoot as external rotation/internal rotation and 10 as abduction/adduction. In all, 2 articles described the transverse (horizontal) plane motion in midfoot as external rotation/internal rotation and 10 as abduction/adduction. Another 4 articles described the transverse (horizontal) plane motion in the forefoot as external rotation/internal rotation and 8 as abduction/adduction. Altogether, 109 articles described the sagittal plane motion of the foot/ankle as dorsiflexion/plantarflexion and 20 as extension/flexion. In all, 99 articles described the frontal (coronal) plane motion of the foot/ankle as inversion/eversion and 4 as supination/pronation. Furthermore, 12 articles described the sagittal plane motion of toes as dorsiflexion/plantarflexion and 15 as extension/flexion. Another 16 articles described the frontal (coronal) plane motion of toes as supination/pronation and 1 as inversion/eversion. The transverse (horizontal) plane motion of the foot/ankle was defined as abduction/adduction in the hindfoot, midfoot, and forefoot; the sagittal plane motion of the foot/ankle was defined as dorsiflexion/plantarflexion; and the frontal (coronal) plane motion of the foot/ankle as inversion/eversion. The transverse (horizontal) plane motion of toes was defined as abduction/adduction; the sagittal plane motion of toes was defined as extension/flexion; and the frontal (coronal) plane motion of toes was defined as supination/pronation.     

Acute effect of orthoses on foot orientation and perceived comfort in individuals with pes cavus during standing

BackgroundChanges in foot orientation due to orthoses and the relationship with perceived comfort are still unclear in pes cavus. The purpose of this study was to determine the acute changes of fore-foot angles due to the use of custom-made orthoses and their relationship with perceived comfort during standing.MethodsTwo photographs were taken using a color-coded camera-based system from the posterior and medial views of 20 subjects with bilateral pes cavus under barefoot and with orthoses conditions during standing. Djian–Annonier, calcaneal inclination, 1st metatarsal declination and rearfoot angles were measured and perceived comfort in the forefoot, midfoot and rearfoot was estimated using an adapted Visual Analogue Scale-type questionnaire.ResultsIn comparison with the barefoot condition, orthoses increased significantly the 1st metatarsal declination angle by 1.9° (p < 0.01), and the Djian–Annonier angle by 1.1° (p = 0.02). The calcaneal inclination angle decreased significantly by an average of 3.0° (p < 0.01). Wearing orthoses significantly improved perceived comfort in forefoot, midfoot and rearfoot when compared to barefoot condition (p < 0.01). A significant correlation was observed between variation of calcaneal inclination angle and the perceived comfort at the midfoot (r = ?0.44; p = 0.04).ConclusionFlattening of foot arch and improvement of midfoot perceived comfort in pes cavus could be attributed to the reduction of the calcaneal inclination angle in the sagittal plane by using orthoses during standing.     

A clinically applicable six-segmented foot model

We describe a multi‐segmented foot model comprising lower leg, rearfoot, midfoot, lateral forefoot, medial forefoot, and hallux for routine use in a clinical setting. The Ghent Foot Model describes the kinematic patterns of functional units of the foot, especially the midfoot, to investigate patient populations where midfoot deformation or dysfunction is an important feature, for example, rheumatoid arthritis patients. Data were obtained from surface markers by a 6 camera motion capture system at 500 Hz. Ten healthy subjects walked barefoot along a 12 m walkway at self‐selected speed. Joint angles (rearfoot to shank, midfoot to rearfoot, lateral and medial forefoot to midfoot, and hallux to medial forefoot) in the sagittal, frontal, and transverse plane are reported according to anatomically based reference frames. These angles were calculated and reported during the foot rollover phases in stance, detected by synchronized plantar pressure measurements. Repeated measurements of each subject revealed low intra‐subject variability, varying between 0.7° and 2.3° for the minimum values, between 0.5° and 2.1° for the maximum values, and between 0.8° and 5.8° for the ROM. The described movement patterns were repeatable and consistent with biomechanical and clinical knowledge. As such, the Ghent Foot model permits intersegment, in vivo motion measurement of the foot, which is crucial for both clinical and research applications. © 2011 Orthopaedic Research Society. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:655–661, 2012     

Transverse patellar fractures“0” fixation system Double-head cannulated compression screw

Purpose: This study evaluated the angular kinematic and moment of the ankle and foot during shod walking and barefoot walking in individuals with unilateral chronic ankle instability (CAI). Methods: Recreational soccer players with unilateral CAI were recruited for this cross sectional study conducted between January and August 2019. A total of 40 participants were screened for eligibility but only 31 met the inclusion criteria based on the methods of Delahunt et al and Gribble et al. Except for 3 participants not attending the evaluation session, 28 participants were finally included. A three dimensional motion analysis system made up of ProReflex motion capture unit and an AMTIb Kistler force plate, embedded in the middle of nine meter walkway, were used to assess the ankle and foot angles and moment during shod walking and barefoot walking conditions. A Statistical Package for Social Sciences (version 20.0) was used to analyze data. Results: During shod walking, the ankle joint plantar-flexion range of motion (ROM) at 10% of the gait cycle (GC) and dorsiflexion ROM at 30% of the GC were significantly higher than those during barefoot walking for both feet (p = 0.001, 0.001, 0.027, and 0.036 respectively). The inversion ROM during shod walking was significantly higher than that during barefoot walking for both feet at 10% and 30% of the GC (p = 0.001. 0.001, 0.001, and 0.042 respectively). At 10% of the GC, the eversion moment was significantly higher between barefoot and shod walking for both feet (both p = 0.001). At 30% of the GC, there was no significant difference between shod and barefoot walking plantar-flexion moment of both feet (p = 0.975 and 0.763 respectively), and the eversion moment of both feet (p = 0.116 and 0.101 respectively). Conclusion: At the early stance, shod walking increases the ankle plantar-flexion and foot inversion ROM, and decreases the eversion moment for both feet in subjects with unilateral CAI. Therefore, the foot wearing condition should be considered during evaluation of ankle and foot kinematics and kinetics.     

Indications for orthoses to improve gait in children with cerebral palsy

Orthoses are frequently used to improve the gait of children with cerebral palsy. Optimal clinical decision-making for improving gait through orthotic management requires an understanding of the biomechanics of the foot and ankle during normal gait, the pathophysiology and pathomechanics of gait disruption in children with cerebral palsy, and the biomechanical characteristics of various orthoses. The clinician must seek to integrate his or her own goals with those of the child and family, the therapist, and the orthotist. Design, indications, and cost should be considered when choosing an orthosis. The physician can construct a paradigm for clinical decision-making, focusing on the evaluation of ankle/foot alignment, range of motion, and assessment of dynamic gait deviations. This paradigm will guide the clinician in the use of orthoses to improve gait in children with cerebral palsy. For optimal orthotic management, the physician must clearly identify the gait deviation and functional deficits to be addressed with the orthosis. The outcome of the orthotic intervention should be documented as objectively as possible.     

Kinetic and Kinematic Evaluation of the Ankle Joint After Achilles Tendon Reconstruction With Free Semitendinosus Tendon Graft: Preliminary Results

Chronic rupture of the Achilles tendon (AT) is a surgical challenge and has effects on the gait. The purpose of this study was to evaluate the kinetic and kinematic parameters of the ankle joint in patients with AT rupture operated using a free semitendinosus tendon graft. Thirteen patients were analyzed 6 and 12 months after surgery in a force platform, while the movements were recorded by six infrared cameras. The kinematic variables analyzed included speed, cadence, step length, percentage of stance phase, and range of movement (ROM) of the ankle joint in the sagittal and frontal planes. Kinetic data were obtained by joint movement in different phases of the gait cycle. Functional assessment was performed using the American Orthopaedic Foot and Ankle Society (AOFAS) score. The patients showed a significant increase (P = 0.0215) in AOFAS from 68.5 (±18.7) to 85.2 (±18.0). Speed, cadence, and length of step of the four groups (1A, 1B, 2A, 2B) were lower than the control group (group 3), and the percentage in stance phase was higher for the nonoperated foot 6‐month group (1B) compared to the control group (group 3). For the kinematic data, the ROM of the ankle in stance phase increased from 6 to 12 months showing an effect of time between four groups (1A, 1B, 2A, 2B). During swing phase, the ankle ROM was lower in the operated side (effect of side, P = 0.0255) and groups 1A and 2A demonstrated statistical differences when compared with the control group (group 3) (P = 0.0240 and P = 0.0414, respectively). ROM of inversion and eversion presented effect of time among the same groups (P = 0.0059) cited before. There were no differences in kinetic data between groups. This study showed close proximity between the control group and the operated group. Furthermore, improvement was shown when comparing the 6 and 12 months postsurgery periods. The surgical procedure is therefore helpful for the patient and few changes were present in gait and ankle biomechanics.     

Lower Extremity Biomechanical Relationships with Different Speeds in Traditional,Minimalist, and Barefoot Footwear

Minimalist running footwear has grown increasingly popular. Prior studies that have compared lower extremity biomechanics in minimalist running to traditional running conditions are largely limited to a single running velocity. This study compares the effects of running at various speeds on foot strike pattern, stride length, knee angles and ankle angles in traditional, barefoot, and minimalist running conditions. Twenty-six recreational runners (19-46 years of age) ran on a treadmill at a range of speeds (2.5-4.0 m·sec^-1). Subjects ran with four different footwear conditions: personal, standard, and minimalist shoes and barefoot. 3D coordinates from video data were collected. The relationships between speed, knee and ankle angles at foot strike and toe-off, relative step length, and footwear conditions were evaluated by ANCOVA, with speed as the co-variate. Distribution of non-rearfoot strike was compared across shod conditions with paired t-tests. Non-rearfoot strike distribution was not significantly affected by speed, but was different between shod conditions (p < 0.05). Footwear condition and speed significantly affected ankle angle at touchdown, independent of one another (F [3,71] = 10.28, p < 0.001), with barefoot and minimalist running exhibiting greater plantarflexion at foot strike. When controlling for foot strike style, barefoot and minimalist runners exhibited greater plantarflexion than other conditions (p < 0.05). Ankle angle at lift-off and relative step length exhibited a significant interaction between speed and shod condition. Knee angles had a significant relationship with speed, but not with footwear. There is a clear influence of footwear, but not speed, on foot strike pattern. Additionally, speed and footwear predict ankle angles (greater plantarflexion at foot strike) and may have implications for minimalist runners and their risk of injury. Long-term studies utilizing various speeds and habituation times are needed.

Key points

• Foot strike style does not change with speed, but does change with shod condition, with minimalist shoes exhibiting an intermediate distribution of forefoot strikes between barefoot and traditional shoes.
• Plantarflexion at touchdown does change with speed and with shoe type, with barefoot and minimalist shoes exhibiting a greater plantarflexion angle than traditional running shoes.
• Knee angles change with speed in all shod conditions, but knee flexion at touchdown is not different between shod conditions.
• Relative step length changes with speed and shod condition, but there is an interaction between these variables such that step length increases more quickly in traditional shoes as speed increases.

Key words: Running, biomechanics, gait analysis, motion analysis/kinesiology, minimalist, shoe wear     

Clinical Outcomes of Total Ankle Arthroplasty Versus Ankle Arthrodesis for the Treatment of End-Stage Ankle Arthritis in the Last Decade: a Systematic Review and Meta-analysis

Ankle arthrodesis (AA) and total ankle arthroplasty (TAA) are the 2 primary surgical treatments for patients with end-stage ankle arthritis. The comparative outcomes between AA and TAA using modern techniques remain unclear. A systematic search to identify all relevant articles comparing AA with TAA was conducted through 3 online databases. The clinical outcomes were extracted for meta-analysis, including AOFAS (American Orthopaedic Foot & Ankle Society) score, VAS (visual analog scale), AOS (Ankle Osteoarthritis Scale), gait analysis, ROM (range of motion), satisfaction, complication, and reoperation. Our meta-analysis shows no heterogeneity in any subgroup analyses. There were no significant differences in AOFAS total, pain, and alignment scores between the AA and TAA groups. The TAA group had significant improvement in AOFAS function score compared with the AA group. There was no significant difference in VAS and AOS total scores between the 2 groups. No significant differences in gait analysis were observed between the 2 groups. The TAA group had significant improvement in both ROM and change in ROM compared with the AA group. There was no significant difference in satisfaction rate between the 2 groups. The TAA group had significantly higher complication and reoperation rates compared with the AA group. Our meta-analysis provides updated evidence on clinical outcomes comparing AA with TAA using third-generation implants. The TAA group had better improvement in AOFAS function and ROM than the AA group. No significant differences in pain relief, gait analysis, or patient satisfaction were observed between the 2 groups.     

Clinical outcome and changes in gait pattern after pilon fractures

Purpose

Axial burst fractures of the distal tibia are challenging to treat and often lead to restricted function of the lower limb. The purpose of this study was to investigate the clinical outcome and changes in gait pattern in such patients.

Methods

Thirty-five patients in a level 1 trauma centre were followed up clinically and by gait analysis. The American Orthopaedic Foot and Ankle Society (AOFAS), visual analogue scale (VAS) foot and ankle scale and Phillips scores were applied. Dynamic pedography (emed-M; Novel, Germany) with analyses of load, pressure and force-time integral were undertaken to investigate possible changes in gait pattern.

Results

Mean follow-up was 50 (19–100) months. Mean AOFAS, VAS foot and ankle and Phillips scores were 65, 63 and 55 points, respectively. There were clear correlations between fracture severity in the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification and functional outcome in AOFAS (−0.63; p < 0.01), VAS foot and ankle scale (−0.56; p < 0.01) and Phillips (−0.64; p < 0.01) scores. There was a high correlation of 0.74 (p < 0.01) between the severity of the injury in the AO-classification and onset of post-traumatic arthrosis. Dynamic pedography revealed lesser load bearing for the total foot, medial foot, heel, first metatarsal and medial forefoot for the affected limb, and increased load bearing was seen in the lateral midfoot region.

Conclusions

Fractures of the tibial pilon lead to restricted function of the lower limb. Clinical outcome correlates with fracture severity in the AO classification, the onset of post-traumatic arthrosis and changes in gait patterns.     

Gait analysis of foot compensation in symptomatic Hallux Rigidus patients

BackgroundCompensatory motion of foot joints in hallux rigidus (HR) are not fully known. This study aimed to clarify the kinematic compensation within the foot and to detect whether this affects plantar pressure distribution.MethodsGait characteristics were assessed in 16 patients (16 feet) with HR and compared with 15 healthy controls (30 feet) with three-dimensional gait analysis by using the multi-segment Oxford Foot Model, measuring spatio-temporal parameters, joint kinematics and plantar pressure.ResultsHR subjects showed less hallux plantar flexion during midstance and less hallux dorsiflexion during push-off, while increased forefoot supination was detected during push-off. No significant differences in plantar pressure were detected. Step length was significantly smaller in HR subjects, while gait velocity was comparable between groups.ConclusionsHR significantly affects sagittal hallux motion, and the forefoot compensates by an increased supination during push-off. Despite this kinematic compensatory mechanism, no significant differences in plantar loading were detected.     

A functional evaluation of prosthetic foot kinematics during lower-limb amputee gait

This paper reports on a functional evaluation of prosthetic feet based on gait analysis. The aim is to analyse prosthetic feet behaviour under loads applied during gait in order to quantify user benefits for each foot. Ten traumatic amputees (six trans-tibial and four trans-femoral) were tested using their own prosthetic foot. An original protocol is presented to calculate the forefoot kinematics together with the overall body kinematics and ground reaction forces during gait. In this work, sagittal motion of the prosthetic ankle and the forefoot, time-distance parameters and ground reaction forces were examined. It is shown that an analysis of not only trans-tibial but also trans-femoral amputees provides an insight in the performance of prosthetic feet. Symmetry and prosthetic propulsive force were proved to be mainly dependant on amputation level. In contrast, the flexion of the prosthetic forefoot and several time-distance parameters are highly influenced by foot design. Correlations show influential of foot and ankle kinematics on other parameters. These results suggest that prosthetic foot efficiency depends simultaneously on foot design and gait style. The evaluation, proposed in this article, associated to clinical examination should help to achieve the best prosthetic foot match to a patient.     

Long-term Results of Comprehensive Clubfoot Release Versus the Ponseti Method: Which Is Better?

Background

Clubfoot can be treated nonoperatively, most commonly using a Ponseti approach, or surgically, most often with a comprehensive clubfoot release. Little is known about how these approaches compare with one another at longer term, or how patients treated with these approaches differ in terms of foot function, foot biomechanics, or quality-of-life from individuals who did not have clubfoot as a child.

Questions/purposes

We compared (1) focused physical and radiographic examinations, (2) gait analysis, and (3) quality-of-life measures at long-term followup between groups of adult patients with clubfoot treated either with the Ponseti method of nonsurgical management or a comprehensive surgical release through a Cincinnati incision, and compared these two groups with a control group without clubfoot.

Methods

This was a case control study of individuals treated for clubfoot at two separate institutions with different methods of treatment between 1983 to 1987. One hospital used only the Ponseti method and the other mainly used a comprehensive clubfoot release. There were 42 adults (24 treated surgically, 18 treated with Ponseti method) with isolated clubfoot along with 48 healthy control subjects who agreed to participate in a detailed analysis of physical function, foot biomechanics, and quality-of-life metrics.

Results

Both treatment groups had diminished strength and motion compared with the control subjects on physical examination measures; however, the Ponseti group had significantly greater ankle plantar flexion ROM (p < 0.001), greater ankle plantar flexor (p = 0.031) and evertor (p = 0.012) strength, and a decreased incidence of osteoarthritis in the ankle and foot compared with the surgical group. During gait the surgical group had reduced peak ankle plantar flexion (p = 0.002), and reduced sagittal plane hindfoot (p = 0.009) and forefoot (p = 0.008) ROM during the preswing phase compared with the Ponseti group. The surgical group had the lowest overall ankle power generation during push off compared with the control subjects (p = 0.002). Outcome tools revealed elevated pain levels in the surgical group compared with the Ponseti group (p = 0.008) and lower scores for physical function and quality-of-life for both clubfoot groups compared with age-range matched control subjects (p = 0.01).

Conclusions

Although individuals in each treatment group experienced pain, weakness, and reduced ROM, they were highly functional into early adulthood. As adults the Ponseti group fared better than the surgically treated group because of advantages including increased ROM observed at the physical examination and during gait, greater strength, and less arthritis. This study supports efforts to correct clubfoot with Ponseti casting and minimizing surgery to the joints, and highlights the need to improve methods that promote ROM and strength which are important for adult function.

Level of Evidence

Level III, prognostic study.     

Foot Pressure Changes Before and After Ankle Fusion: A Pedobarograph Study

We performed a case-control study with the purpose of establishing the pressure patterns in the soles of the feet of patients with ankle osteoarthritis, determining whether the pattern changed after treating the arthritis with ankle joint fusion (arthrodesis), and whether the change is significant. We also studied the benefits of ankle fusion with respect to the Short-Form 36-item Health Survey and the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale. The study included 18 participants (9 in the study group and 9 in the control group) to reach statistical significance with a 95% confidence interval (CI). A demonstrable increase was found in both forefoot and hind-foot pressures in the study group preoperatively compared with the control group. Also, a demonstrable increase was found in the pressure in both the forefoot (mean difference 50.56 ± 267.39 kPa) and the hindfoot (mean difference 57.44 ± 160.27 kPa) from preoperatively to postoperatively. This difference was not statistically significant (p = .59 [t(8) = 0.57]; 95% CI 256.10 to ?154.98) for the forefoot pressures and for the hindfoot pressures (p = .31 [t(8) = 1.08]; 95% CI 180.64 to ?65.76). The Short-Form 36-item scores significantly improved from preoperatively to postoperatively (p = .000054 for the physical component and p = .018 for the mental component). The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale score also improved significantly (p = .0000005). The foot pressures, as measured by using the insole sensors, showed an increase in forefoot and hindfoot pressures that was not statistically significant.     

Effect of Acute Alterations in Foot Strike Patterns during Running on Sagittal Plane Lower Limb Kinematics and Kinetics

The purpose of this study was to determine the effect of foot strike patterns and converted foot strike patterns on lower limb kinematics and kinetics at the hip, knee, and ankle during a shod condition. Subjects were videotaped with a high speed camera while running a 5km at self-selected pace on a treadmill to determine natural foot strike pattern on day one. Preferred forefoot group (PFFG, n = 10) and preferred rear foot group (PRFG, n = 11) subjects were identified through slow motion video playback (n = 21, age = 22.8±2.2 years, mass = 73.1±14.5 kg, height 1.75 ± 0.10 m). On day two, subjects performed five overground run trials in both their natural and unnatural strike patterns while motion and force data were collected. Data were collected over two days so that foot strike videos could be analyzed for group placement purposes. Several 2 (Foot Strike Pattern –forefoot strike [FFS], rearfoot strike [RFS]) x 2 (Group – PFFG, PRFG) mixed model ANOVAs (p < 0.05) were run on speed, active peak vertical ground reaction force (VGRF), peak early stance and mid stance sagittal ankle moments, sagittal plane hip and knee moments, ankle dorsiflexion ROM, and sagittal plane hip and knee ROM. There were no significant interactions or between group differences for any of the measured variables. Within subject effects demonstrated that the RFS condition had significantly lower (VGRF) (RFS = 2.58 ± .21 BW, FFS = 2.71 ± 0.23 BW), dorsiflexion moment (RFS = -2.6 1± 0.61 Nm·kg^-1, FFS = -3.09 ± 0.32 Nm·kg^-1), and dorsiflexion range of motion (RFS = 17.63 ± 3.76°, FFS = 22.10 ± 5.08°). There was also a significantly higher peak plantarflexion moment (RFS = 0.23 ± 0.11 Nm·kg^-1, FFS = 0.01 ± 0.01 Nm·kg^-1), peak knee moment (RFS = 2.61 ± 0.54 Nm·kg^-1, FFS = 2.39 ± 0.61 Nm·kg^-1), knee ROM (RFS = 31.72 ± 2.79°, FFS = 29.58 ± 2.97°), and hip ROM (RFS = 42.72 ± 4.03°, FFS = 41.38 ± 3.32°) as compared with the FFS condition. This research suggests that acute changes in foot strike patterns during shod running can create alterations in certain lower limb kinematic and kinetic measures that are not dependent on the preferred foot strike pattern of the individual. This research also challenges the contention that the impact transient spike in the vertical ground reaction force curve is only present during a rear foot strike type of running gait.

Key points

• Footstrike pattern changes should be individually considered and implemented based on individual histories/abilities
• Forefoot strike patterns increase external dorsiflexion moments
• Rearfoot strike patterns increase external knee flexion moments
• Recreational shod runners are able to mimic habitual mechanics of different foot strike patterns

Key words: Forefoot, rearfoot, joint moments, range of motion     

The association between foot posture,single leg balance and running biomechanics of the foot

ObjectivesA mal-aligned foot posture (high-arched and flat feet) and poor single leg balance ability have been separately associated with foot injuries during running. Therefore, clinicians assess these routinely. However, the extent to which foot posture and single-leg balance ability affect actual foot biomechanics during running is not known. This study aims to investigate the association of foot posture, single-leg balance ability, and foot biomechanics during running.MethodThis is a cross sectional study of sixty-nine participants who had their foot postures and single-leg balance ability assessed. The Foot Posture Index and Balance Error Scoring System were used. Their foot kinetics was measured as they ran on an instrumented treadmill and foot kinematics was processed using a 3D motion capture system. Multiple-regression was used to analyse the variance of foot biomechanics explained by foot posture and single-leg balance ability.ResultsFoot posture and single-leg balance ability were found to account significantly for the variance in rearfoot eversion (24%) and forefoot dorsiflexion (7%). Two regression equations were derived, where rearfoot eversion and forefoot dorsiflexion during running may be predicted.ConclusionFoot posture and single-leg balance ability can predict rearfoot eversion and forefoot dorsiflexion only during running. Based on the regression equations, individuals with the same foot posture but different single-leg balance ability may exhibit different foot kinematics. However, the angular differences are small. The equations may be useful for clinicians working in places where running gait analysis equipment are not readily accessible. Further studies with larger sample sizes are required to validate these equations. In addition, further studies are necessary to investigate the effect of these two variables under different running conditions e.g. with footwear and with orthoses.