Kinematics and muscle forces in women with patellofemoral pain during the propulsion phase of the single leg triple hop test

BackgroundApproximately 25% of orthopedic knee conditions are related to patellofemoral pain (PFP), with young women being the most affected. It is thought that this condition is associated with modifications in the kinematics and muscle control patterns of the lower limb during weight-bearing support activities, which increases femur movement under the patella.ObjectivesTo compare kinematics and muscle induced acceleration patterns between PFP subjects and healthy controls during the preparation phase of the single leg triple hop test.Study designBiomechanical analysis was performed using OpenSim. Ten physically active women (23.2 ± 4 years, 59.3 ± 5.8 kg, and 1.63 ± 0.06 m) with no history of lower limb injury (CG) and 11 volunteers (23.5 ± 2 years, 55.4 ± 4.9 kg, and 1.66 ± 0.04 m) with PFP (PFPG) were recruited. The participants performed a series of single leg triple hop tests while the ground reaction forces and kinematic data were recorded.ResultsVector field statistical analysis indicated increased lumbar extension, anterior pelvic tilt, contralateral pelvic drop, and lower induced accelerations from the core and hip muscles in PFPG.ConclusionPFP volunteers presented with alterations in lumbar muscle control associated with a possible compensatory pelvic strategy to minimize knee extensor moment.     

Kinematic gait characteristics associated with patellofemoral pain syndrome: A systematic review

Development of patellofemoral pain syndrome (PFPS) is considered to be multifactorial. The aims of this systematic review were to (i) summarise and critique the body of literature addressing kinematic gait characteristics associated with PFPS; and (ii) provide recommendations for future research addressing kinematic gait characteristics associated with PFPS. A comprehensive search of MEDLINE, EMBASE, CINAHL, and Current Contents revealed 561 citations for review. Each citation was assessed for inclusion and quality using a modified version of the ‘Quality Index’ and a novel inclusion/exclusion criteria checklist by two independent reviewers. A total of 24 studies were identified. No prospective studies with adequate data to complete effect size calculations were found. Quality of included case–control studies varied, with a number of methodological issues identified. Heterogeneity between studies made meta-analysis inappropriate. Reductions in gait velocity were indicated during walking, ramp negotiation, and stair negotiation in individuals with PFPS. Findings indicated delayed timing of peak rearfoot eversion and increased rearfoot eversion at heel strike transient during walking; and delayed timing of peak rearfoot eversion, increased rearfoot eversion at heel strike, reduced rearfoot eversion range, greater knee external rotation at peak knee extension moment, and greater hip adduction during running in individuals with PFPS. There is a clear need for prospective evaluation of kinematic gait characteristics in a PFPS population to distinguish between cause and effect. Where possible, future PFPS case–control studies should consider evaluating kinematics of the knee, hip and foot/ankle simultaneously with larger participant numbers. Completing between sex comparisons when practical and considering spatiotemporal gait characteristics during methodological design and data analysis is also recommended.     

Patellar bracing affects sEMG activity of leg and thigh muscles during stance phase in patellofemoral pain syndrome

BackgroundDecreases in patellofemoral pain symptoms with bracing treatment have been established; but, the mechanisms remain unclear. The purpose of this study was to determine the immediate and long-term effects of the patellar bracing on electromyography (EMG) activity of the Vastus Medialis (VM) and Lateralis (VL), Rectus Femoris, lateral Gastrocnemius, Biceps Femoris and Semitendinosus (ST) muscles during level walking.Methods12 eligible women aged 20–30 years with diagnosis of patellofemoral pain participated in the before and after study. Intervention consisted of 8 weeks of patellar bracing. First, patients were tested without brace, then with a brace, and finally eight weeks later without a brace. Surface EMG activation of the selected muscles during level walking was recorded.ResultsAfter eight weeks of patellar bracing, EMG activity of VM muscle was significantly higher when compared to first session without brace (p = 0.011) at mid-stance sub-phase. Additionally, EMG activity of ST muscle during first session with brace was significantly lower when compared to first session without brace at mid-stance sub-phase (without brace) (p = 0.012). EMG activity of VM muscle after eight weeks of patellar bracing was significantly higher than the first session without brace at late stance and preswing sub-phase (p = 0.013).ConclusionLong-term wearing of patellar bracing increases EMG activity of VM during mid-stance and late stance and preswing sub-phases of gait and immediate effect of patellar brace is decrease of EMG activity of ST muscle during mid-stance.     

Femoral medial deviation angle during a one-leg squat test in individuals with patellofemoral pain syndrome

ObjectivesPatients with patellofemoral pain syndrome (PFPS) often demonstrate a collapse of the knee in the medial direction during a one-leg squat. This study investigated the medial displacement magnitude of the knee during a one-leg squat test in females with PFPS.DesignThe study design was a cross sectional comparative investigation.ParticipantsThirteen healthy females and 12 females with PFPS.Main measuresParticipants were tested during a one-leg squat test using a single camera. The thigh segment alignment in the frontal plane was measured by the angle projected between the long axis of the thigh and the foot (femoral frontal angle) and the horizontal deviation (femoral deviation) of the distal thigh relative to the foot.ResultsA one-way ANOVA showed that the femoral frontal angle was significantly larger (p=0.019) for the PFPS group with no significant differences for the femoral deviation (p=0.288). Both measurements showed good trial-to-trial reliability while the femoral frontal angle showed good test–retest reliability.ConclusionThe increased femoral frontal angle magnitude during the one-leg squat demonstrates that the one-leg squat may be a useful clinical tool for the evaluation process of PFPS.     

Patellofemoral morphometry in patients with idiopathic patellofemoral pain syndrome

Purpose

To compare clinical and computed tomography (CT) measures in extension, 20° and 30° of flexion of symptomatic knees of patient with idiopathic patellofemoral pain syndrome with the contra lateral asymptomatic knee.

Materials and methods

Knees of 52 consecutive patients with idiopathic patellofemoral pain were studied with CT. In 28 patients this condition was unilateral and asymptomatic knee was used as control; 76 knees were symptomatic.

Results

In patients with idiopathic patellofemoral pain we found a greater Q angle and internal condylar facet width in symptomatic knees with regard to asymptomatic knees.

Conclusion

Greater Q angle and medial condylar facet can lead to overpressure on the medial knee compartment during maneuvers that increase contact between patella and medial condylar facet, such as knee flexion and squatting, contributing to development of idiopathic patellofemoral pain.     

Personality in patients with long-term patellofemoral pain syndrome

Personality characteristics in patients with long-term patellofemoral pain were compared to those of matched controls and other groups both of non-patients and of psychiatric outpatients with character disorders. Personality was described using the self-administered dependency and alexithymia scales, the Karolinska Scales of Personality and the Rorschach inkblot method. The hypothesis was that the patellofemoral pain patients would have higher levels of anxiety, depression, helplessness, aggression and alexithymic characteristics than the matched controls. There were only a few significant differences between the knee patients and the matched controls. The Rorschach measures suggested significantly greater depression, hostility and passive attitude in the knee patients as compared to the reference data. There were no indications of the hypothesised alexithymic characteristics in the knee patients. If patellofemoral pain patients do not improve as expected, referral to a pain clinic with psychological expertise could be considered.     

The effects of McConnell patellofemoral joint and tibial internal rotation limitation taping techniques in people with Patellofemoral pain syndrome

BackgroundTaping is frequently used as part of the multi-modal management for patellofemoral pain syndrome (PFPS). McConnell Patellofemoral Joint Taping (PFJT) and Tibial Internal Rotation Limitation Taping (TIRLT) are proposed to be useful adjuncts to the management of PFPS. However, it is unclear if TIRLT offers similar benefits to PFJT, and its effect on pain and lower limb kinematics have not been investigated previously.Research questionWhat are the effects of TIRLT, PFJT and no taping on perceived pain and lower limb kinematics during a lunge and single leg squat (SLS) in people with PFPS?MethodsThis cross-sectional study compared the effects of TIRLT, PFJT and no taping, on knee pain and lower limb kinematics during two pain-provoking movements in people with PFPS. Participants with PFPS (n = 23) performed a lunge and SLS under three randomised conditions: TIRLT, PFJT and no taping. The Codamotion system captured and analysed lower limb kinematic data in the sagittal, transverse and coronal planes. Peak knee pain intensity during the movement was assessed using the Numerical Rating Scale (NRS).ResultsParticipants reported significantly less pain with the TIRLT and PFJT techniques compared with no tape during the lunge (p = 0.005 and p = 0.011, respectively) and SLS (p= 0.002 and p = 0.001, respectively). There was no evidence of altered lower limb kinematics accompanying pain reductions with either taping technique.SignificanceBoth forms of taping may be useful adjuncts as the short-term benefit of pain relief may enable participation in more active forms of rehabilitation.     

Trunk,pelvis, and knee kinematics during running in females with and without patellofemoral pain

BackgroundFemales are two times more likely to develop patellofemoral pain (PFP) than males. Abnormal trunk and pelvis kinematics are thought to contribute to the pathomechanics of this condition. However, there is a scarcity of evidence investigating proximal segments kinematics in females with PFP.Research questionThe purpose of this study was to investigate whether females with PFP demonstrate altered trunk, pelvis, and knee joint kinematics compared with healthy controls during running.MethodsThirty-four females (17 PFP, 17 controls) underwent a 3-dimensional motion analysis during treadmill running at preferred and fixed speeds, each trial for 30 s. Variables of interest included magnitudes of peak angles for trunk (forward flexion, ipsilateral trunk lean), pelvis (anterior tilt, contralateral drop), knee (flexion, valgus, internal rotation), range of motion (RoM) of trunk and pelvis in sagittal and frontal planes and RoM of knee joint in the three cardinal planes of motion. Kinematic data were compared between groups using mixed model repeated measure analysis of variance with the trial as the repeated measure.ResultsThe PFP group displayed significantly less pelvis frontal plane RoM, greater knee frontal plane RoM, and less knee sagittal plane RoM during running compared with controls, irrespective of running trial. No differences were found in peak kinematic variables between PFP and healthy groups.SignificanceThese results may suggest a rigid stabilization strategy at the pelvis, which the body has adapted to prevent further frontal plane knee malalignment. Less knee sagittal plane RoM may be indicative of another protective strategy in the PFP group to avoid patellofemoral joint reaction force. Clinical assessments and rehabilitative treatments may benefit from considering a global program with focus on pelvis kinematics in addition to the knee joint in females with PFP.     

髌股疼痛综合征患者髌骨运动轨迹的动态CT研究

目的 应用320排动态容积CT描述髌股疼痛综合征患者在膝关节屈曲运动中的动态髌骨轨迹,为髌股疼痛综合征的临床诊断及治疗方案的选择提供理论依据.方法 随机选择济南军区总医院2010年3月～2011年2月间资料完整确诊髌股疼痛综合征的女性患者24例（32膝）为实验组,年龄18～46岁,平均年龄31.1岁;随机选择健康女性13例（26膝）为对照组,年龄19～45岁,平均年龄32.1岁.应用320排动态容积CT检查：股四头肌等长收缩状态下自主屈曲膝关节,在膝关节屈曲0°～120°范围内间隔15°依次垂直髌骨进行动态CT扫描.应用Vitrea 2.1软件进行图像后处理,获得膝关节三维重建图像,测量髌骨运动轨迹参数：髌骨倾斜、髌骨移位和髌骨旋转.所有计数资料以均数和标准差描述,应用SPSS 16.0软件进行两样本均数t检验,P≤0.05有显著性意义.结果 15°～45°范围内两组的髌骨倾斜有显著性差异,P＜0.001;膝关节屈曲15°～45 °范围内两组的髌骨中心外移有显著性差异,P＜0.001;15°～120°范围内两组的髌骨旋转有显著性差异,P＜0.001.结论 膝关节屈曲15°～45°范围内髌股疼痛综合征患者的髌骨轨迹最具临床诊断、治疗意义.     

Effect of patellofemoral pain on foot posture and walking kinematics

Background Excessive pronation has been implicated in patellofemoral pain (PFP) aetiology and foot orthoses are commonly prescribed for PFP patients. Pronation can be assessed using foot posture tests, however, the utility of such tests depends on their association with foot and lower-limb kinematics.Research questions Do PFP participants compared with healthy participants (1) have a more pronated foot measured with static foot tests and a kinematic multi-segmental foot model and (2) is there an association between static foot posture and foot and lower limb kinematics during walking?Methods A case-control study including 22 participants (n = 11 PFP, 5 females per group, aged 24 ± 3 (mean ± SD) years) was conducted. Foot posture measures included Arch Height Ratio, Navicular Drop (ND), and Foot Posture Index. Between-group comparisons of foot posture, segment and joint angle magnitudes, and associations between foot posture and kinematic data during gait were evaluated.Results There were no group differences in foot posture tests and mean joint angles. PFP participants had greater internal rotation of the shank and rearfoot segments, and adduction of the mid- and forefoot in the transverse plane (all p < 0.05). Greater ND was associated with increased forefoot abduction (rho=-0.68, p = 0.02) in healthy participants but no relationships were found between foot posture and kinematics in PFP participants.Significance Foot posture and kinematic data did not indicate excessive pronation in PFP participants questioning the use of orthoses to correct pronation. Larger studies are needed to determine the utility of foot posture tests as indicators of gait abnormalities in PFP.     

Primary cartilage lesions and outcome among subjects with patellofemoral pain syndrome

We investigated the association between cartilage lesion and future symptoms in two groups of subjects with patellofemoral pain syndrome (PFPS). Group A consisted of 31 men (mean age 20.9 years, range 19–32) and group B of 28 consecutive patients (12 men and 16 women; mean age 27.8 years, range 15–50) operated on for PFPS. The mean follow-up time was 3.4 (range 1–7) years in group A and 4.9 (range 1–6) years in group B. At follow-up the subjects in group A with severe cartilage lesion (n=10) reported more knee symptoms as measured by their Kujala score (mean 75.1, SE 3.6 vs. 88.5, SE 2.4) than those with minor cartilage lesion (n=21) (age and follow-up time-adjusted P<0.01). In group B the subjects with severe cartilage lesion tended to report more knee symptoms according to their Kujala score (mean 71.0, SE 7.0 vs. 86.1, SE 5.9; age, sex and follow-up time-adjusted P=0.15) and VAS score (mean 51.8, SE 11.8 vs. 12.7, SE 10.4; adjusted P=0.04) than the subjects without cartilage lesion. Our study shows that among the patients with PFPS, the subjects with severe cartilage lesion of the patella or femoral trochlea reported more subjective symptoms and functional limitations at follow-up than those without or with small cartilage lesion of the patella or femoral trochlea.     

Relationship among eccentric hip and knee torques, symptom severity and functional capacity in females with patellofemoral pain syndrome

Objective

To determine the relationships between eccentric hip and knee torques, symptom severity and functional capacity in females with patellofemoral pain syndrome (PFPS).

Design

Within-subject correlational study.

Setting

University biomechanics laboratory.

Participants

10 females diagnosed with PFPS.

Main outcome measures

Eccentric strength of the hip abductors and lateral rotators, and knee extensors were assessed using an isokinetic dynamometer. A 10-cm visual analog scale was used to determine usual knee pain in the last week. The Anterior Knee Pain Scale (AKPS) was used to determine the functional capacity of the patients.

Results

The study found that the greater the eccentric knee extensor and hip lateral rotator torques, the higher the functional capacity of the patients (p = 0.02, r = 0.72; p = 0.02, r = 0.72). It was also shown that the greater hip lateral rotator torque, the less the usual pain reported in the last week (p = 0.004, r = −0.84). Despite the lack of statistical significance (p = 0.11), it was also found a modest negative relationship between the eccentric knee extensor torque and the usual pain reported in the last week (r = −0.56) that was considered clinically meaningful (d = 1.4).

Conclusions

This study showed that eccentric knee extensor and hip lateral rotator torques were associated with functional capacity and pain level in females with PFPS. Further investigations should be carried out to verify the effects of an intervention program focused on the eccentric action of these muscles with respect to the symptoms in patients with PFPS.     

The effects & mechanisms of increasing running step rate: A feasibility study in a mixed-sex group of runners with patellofemoral pain

ObjectivesTo explore feasibility of recruitment and retention of runners with patellofemoral pain (PFP), before delivering a step rate intervention.DesignFeasibility study.SettingHuman performance laboratory.ParticipantsA mixed-sex sample of runners with PFP (n = 11).Main outcome measuresAverage/worst pain and the Kujala Scale were recorded pre/post intervention, alongside lower limb kinematics and surface electromyography (sEMG), sampled during a 3 KM treadmill run.ResultsRecruitment and retention of a mixed-sex cohort was successful, losing one participant to public healthcare and with kinematic and sEMG data lost from single participants only. Clinically meaningful reductions in average (MD = 2.1, d = 1.7) and worst pain (MD = 3.9, d = 2.0) were observed. Reductions in both peak knee flexion (MD = 3.7°, d = 0.78) and peak hip internal rotation (MD = 5.1°, d = 0.96) were observed, which may provide some mechanistic explanation for the identified effects. An increase in both mean amplitude (d = 0.53) and integral (d = 0.58) were observed for the Vastus Medialis Obliqus (VMO) muscle only, of questionable clinical relevance.ConclusionsRecruitment and retention of a mixed sex PFP cohort to a step rate intervention involving detailed biomechanical measures is feasible. There are indications of both likely efficacy and associated mechanisms. Future studies comparing the efficacy of different running retraining approaches are warranted.     

Is markerless,smart phone recorded two-dimensional video a clinically useful measure of relevant lower limb kinematics in runners with patellofemoral pain? A validity and reliability study

ObjectivesInvestigate the validity and reliability of markerless, smart phone collected, two-dimensional (2D) video, analysed using the ‘Hudl technique’ application, compared to three-dimensional (3D) kinematics during running, in participants with patellofemoral pain (PFP).DesignValidity/reliability study.SettingBiomechanics laboratory.ParticipantsMales/females with PFP (n = 21, 10 males, 11 females, age 32.1 months [±12.9]).Main outcome measuresManually synchronised 2D and 3D measurement of peak hip adduction (HADD) and peak knee flexion (KFLEX) during running.Results2D and 3D measures of peak KFLEX (p = 0.02, d = 1.13), but not peak HADD (p = 0.25, d = −0.27), differed significantly. Poor validity was identified for 2D measurement of peak HADD (ICC 0.06, 95% CI -0.35, 0.47) and peak KFLEX ICC 0.42, 95% CI (−0.10, 0.75). Moderate intra-rater reliability was identified for both variables (ICC 0.61–65), alongside moderate inter-rater reliability for peak KFLEX (ICC 0.71) and poor inter-rater reliability for peak HADD (ICC 0.31).ConclusionsMeasurement of peak HADD and KFLEX in runners with PFP using markerless, smart phone collected 2D video, analysed using the Hudl technique Application is invalid, with poor to moderate reliability. Investigation of alternate 2D video approaches to increase precision is warranted. At present, 2D video analysis of running using Hudl Technique cannot be advocated.     

Runners with patellofemoral pain have altered biomechanics which targeted interventions can modify: A systematic review and meta-analysis

Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms.     

Walking mechanics for patellofemoral pain subjects with similar self-reported pain levels can differ based upon neuromuscular activation

Patellofemoral pain (PFP) is often studied on subjects who are classified using only self-reported data. Neuromuscular activation influences movement mechanics for PFP subjects, but is not likely to be self-reported. We compared lower-extremity mechanics, during a common movement (walking), between two subdivisions of a group of PFP subjects that were similar, based on common self-report tools, but different, based on a common objective measure of quadriceps activation. Our intent was to highlight the importance of objectively considering neuromuscular activation when researching PFP movement mechanics. Thirty similar PFP research subjects (based on four common self-report tools) were divided into two subdivisions, based on different quadriceps central activation ratios (CAR): a quadriceps deficit (QD; CAR <0.95) group and a no quadriceps deficit (NQD; CAR ≥0.95) group. All subjects in both groups performed five walking trials, while common mechanical characteristics were measured: 3D ground reaction force, and 3D joint kinematics and kinetics. Functional statistics were used to compare mechanical characteristics between the groups across the entire stance phase of gait (α = 0.05). Numerous differences were found between the two groups for ground reaction force, and joint kinematics and kinetics. For example, the NQD group exhibited 5% greater vertical ground reaction force at peak impact, and 5% less vertical ground reaction force during the unloading portion of stance, relative to the QD group. The results indicate that when researching movement mechanics associated with PFP, it is important to consider objectively-measured neuromuscular activation characteristics that are not likely to be self-reported by PFP subjects.     

Quality of life in individuals with patellofemoral pain: A systematic review including meta-analysis

ObjectiveThe aim of this systematic review is to describe QoL in individuals with PFP, and determine the impact of PFP interventions on QoL.MethodsFive databases were searched for studies reporting QoL in individuals with PFP, with mean age under 50 years. Data were pooled based on QoL tool (e.g. Knee Injury and Osteoarthritis Outcome Score [KOOS] QoL subscale, Short-Form 36 item health survey [SF-36]) using random-effects models, or through narrative synthesis where inadequate data were available.ResultsIndividuals with PFP, had worse KOOS-QOL scores (pooled mean: 47[95% CI: 34 to 61] and health-related QoL (pooled SF-36 PCS and MCS: 47[95% CI: 41 to 53] and 54[95% CI: 47 to 62], respectively) compared with pain-free controls and population norms. Physical interventions were associated with improvements in knee- and health-related QoL in individuals with PFP in repeated measures studies. However, the effect of physical interventions compared to a control treatment was conflicting.ConclusionIndividuals with PFP aged under 50 years, have markedly reduced knee- and health-related QoL compared to pain-free controls and population norms. Knee- and health-related QoL may improve following intervention, but it is unclear if these improvements are greater than that which occur in a control group.     

Internal and external focus show similar effect on the gait kinematics in patients with patellofemoral pain: A randomised controlled trial

PurposeThe purpose of this study was to examine how attentional focus during training influences the effects of a 6-week hip-knee strength training program on pain, function, strength, and kinematics in males and females with Patellofemoral pain (PFP).MethodsSeventy-five males and females with PFP were randomly allocated to a group that trained with an internal focus (n = 25), a group that trained with an external focus (n = 25), or a control group (n = 25). All patients completed testing before (baseline) and after (posttest) the 6-week period. The primary outcome was pain, assessed by Visual Analog Scale (VAS). The secondary outcomes were function, hip muscles strength and lower extremity kinematics, assessed by Kujala Questionnaire, handheld dynamometer and a 2-D motion capture, respectively. All outcomes were measured at the baseline and after the 6-week intervention. Analysis of covariance was used to compare posttest outcomes among the groups while accounting for group differences in baseline performance.ResultsThe hip-knee strengthening exercises resulted in improved knee valgus (ES(95 % CI) = 0.43(0.26 to 0.75), p = 0.03), and external rotator strength (ES(95 % CI) = 0.51(0.12 to 0.78), p = 0.03) for males and females who trained with an external compared to internal focus.ConclusionsOur findings indicate that males and females with PFP may benefit from completing a hip-knee strengthening training program with an external focus vs. an internal focus. Physical therapists and clinicians should consider using instructions that promote an external focus when implementing hip-knee strengthening training programs with PFP patients. This result could be strengthened or re-enforced by larger studies with longer follow up.