Wendy I Drechsler

Effects of open versus closed kinetic chain training on knee laxity in the early period after anterior cruciate ligament reconstruction

Abstract. Knee extensor resistance training using open kinetic chain (OKC) exercise for patients recovering from anterior cruciate ligament reconstruction (ACLR) surgery has lost favour mainly because of research indicating that OKC exercise causes greater ACL strain than closed kinetic chain (CKC) exercise. In this prospective, randomized clinical trial the effects of these two regimes on knee laxity were compared in the early period after ACLR surgery. Thirty-six patients recovering from ACLR surgery (29 males, 7 females; age mean=30) were tested at 2 and 6 weeks after ACLR with knee laxity measured using the Knee Signature System arthrometer. Between tests subjects trained using either OKC or CKC resistance of their knee and hip extensors in formal physical therapy sessions three times per week. Following adjustment for site of treatment, pretraining injured knee laxity, and untreated knee laxity at post-training, the use of OKC exercise, when compared to CKC exercise, was found to lead to a 9% increase in looseness with a 95% confidence interval of –8% to +29%. These results indicate that the great concern about the safety of OKC knee extensor training in the early period after ACLR surgery may not be well founded.

Open and Closed Kinetic Chain Exercises in the Early Period after Anterior Cruciate Ligament Reconstruction: Improvements in Level Walking, Stair Ascent, and Stair Descent

Thirty-seven patients who had undergone anterior cruciate ligament reconstruction were tested in a gait analysis laboratory at 2 and 6 weeks after surgery. Between test sessions, patients were randomly assigned to a course of either closed or open kinetic chain resistance exercises (3 sessions per week for 4 weeks). Gait analysis consisted of bilateral calculations of knee joint angle, moment, and power during level walking, stair ascent, and stair descent. An analysis of variance on the effects of training group and test session indicated that the only variable to be significantly affected by the type of exercise program was the amount of knee flexion at the beginning of step-up (P<0.05). All other measures of knee angle, moment, and power (16 total variables) showed no significant difference between the exercise groups. All variables measured on the injured side showed significant improvement from test 1 to test 2 (P<0.05), but the injured leg remained functionally deficient when compared with the uninjured leg. These data suggest that there are no clinically significant differences in the functional improvement resulting from the choice of open or closed kinetic chain exercises in the early period after this surgery.

Gait analysis 6 and 12 months after anterior cruciate ligament reconstruction surgery.

Little is known about knee function after anterior cruciate ligament reconstruction in the vital activities of walking and stair use. Gait analysis was done on patients 6 months (n = 8) and 12 months (n = 9) after reconstruction of the anterior cruciate ligament. Paired t tests were used to compare the injured and uninjured knees. During level walking, the patients placed external flexion torques on their injured knees throughout midstance, indicating the absence of quadriceps avoidance gait. The peak external flexion torque (resisted by the knee extensor muscles) placed on the injured knee was significantly less than that of the uninjured knee when ascending stairs (at 12 months, 68.4 and 85.3 N-m in the injured and uninjured knees, respectively) and also when descending stairs (at 12 months, 70.8 and 81.7 N-m in the injured and uninjured knees, respectively). The injured knee produced significantly less power than the uninjured knee when ascending stairs, but this difference was not significant when descending stairs. These findings indicate that asymmetric gait patterns persisted up to 1 year after surgical reconstruction and were more pronounced during stair ascent and descent than in level walking. These results indicate that clinicians should include specific interventions targeted at improving knee function during stair use to restore normal function after anterior cruciate ligament reconstruction.

Relationship of leg muscle strength and knee function in the early period after anterior cruciate ligament reconstruction.

The purpose of this descriptive study was to assess the relationship between knee function and the strength testing performance of various leg muscles in the early period after anterior cruciate ligament reconstruction (ACLR). Twenty‐four patients who had recent ACLR (seven females and 17 males, mean age=27 years) were tested for leg muscle strength and knee function 2 weeks after surgery. The concentric peak torques of the hip and knee extensors and knee flexors were measured at 210° s−1. In addition, the latter two muscle groups were measured at 60° s−1, and also isometrically (at a knee angle of 60°). Knee function was assessed using a three‐dimensional motion analysis system combined with a force platform. This system determined knee joint angles, torques and powers during level walking, stair ascent and stair descent. Pearsons correlation coefficients were calculated to assess the relationships between the injured knee function variables and the injured/uninjured strength ratios. The correlation coefficients ranged (in absolute value) from 0.03 to 0.81, and were generally higher for the stair tasks compared with level walking, and highest for the knee extensors (as compared with the knee flexors and hip extensors), and the strength test velocity appears much less important than the muscle group tested. These results contribute evidence indicating the importance of knee extensor strength to knee function in the early period after ACLR.

Comparison of biomechanical gait parameters of young children with haemophilia and those of age-matched peers

Summary.  Quality of life for children with haemophilia has improved since the introduction of prophylaxis. The frequency of joint haemorrhages has reduced, but the consequences of reduced bleeding on the biomechanical parameters of walking are not well understood. This study explored the differences in sagittal plane biomechanics of walking between a control group (Group 1) of normal age‐matched children and children with haemophilia (Group 2) with a target ankle joint. A motion capture system and two force platforms were used to collect sagittal plane kinematic, kinetic and temporal–spatial data during walking of 14 age‐matched normal children and 14 children with haemophilia aged 7–13 years. Group differences in maximum and minimum flexion/extension angles and moments of the hip, knee and ankle joints, ground reaction forces and temporal–spatial gait cycle parameters were analysed using one‐way anova. Significant changes (P < 0.05) in kinematic and kinetic parameters but not temporal–spatial parameters were found in children with haemophilia; greater flexion angles and external moments of force at the knee, greater ankle plantarflexion external moments and lower hip flexion external moments. These results suggest that early biomechanical changes are present in young haemophilic children with a history of a target ankle joint and imply that lower limb joint function is more impaired than current clinical evaluations indicate. Protocols and quantitative data on the biomechanical gait pattern of children with haemophilia reported in this study provide a baseline to evaluate lower limb joint function and clinical progression.

The reliability of plantar pressure assessment during barefoot level walking in children aged 7-11 years

BackgroundPlantar pressure assessment can provide information pertaining to the dynamic loading of the foot, as well as information specific to each region in contact with the ground. There have been few studies which have considered the reliability of plantar pressure data and therefore the purpose of this study was to investigate the reliability of assessing plantar pressure variables in a group of typically developing children, during barefoot level walking.MethodsForty-five participants, aged 7 to 11 years, were recruited from local primary and secondary schools in East London. Data from three walking trials were collected at both an initial and re-test session, taken one week apart, to determine both the within- and between-session reliability of selected plantar pressure variables. The variables of peak pressure, peak force, pressure-time and force-time integrals were extracted for analysis in the following seven regions of the foot; lateral heel, medial heel, midfoot, 1st metatarsophalangeal joint, 2nd-5th metatarsophalangeal joint, hallux and the lesser toes. Reliability of the data were explored using Intra Class Correlation Coefficients (ICC 3,1 and 3,2) and variability with Coefficients of Variation (CoVs).ResultsThe measurements demonstrated moderate to good levels of within-session reliability across all segments of the foot (0.69-0.93), except the lesser toes, which demonstrated poor reliability (0.17-0.50). CoVs across the three repeated trials ranged from 10.12-19.84% for each of the measured variables across all regions of the foot, except the lesser toes which demonstrated the greatest variability within trials (27.15-56.08%). The between-session results demonstrated good levels of reliability across all foot segments (0.79-0.99) except the lesser toes; with moderate levels of reliability reported at this region of the foot (0.58-0.68). The CoVs between-sessions demonstrated that the midfoot (16.41-36.23%) and lesser toe region (29.64-56.61) demonstrated the greatest levels of variability across all the measured variables.ConclusionsThese findings indicate that using the reported protocols, reliable plantar pressure data can be collected in children, aged 7 to 11 years in all regions of the foot except the lesser toes which consistently reported poor-to-moderate levels of reliability and increased variability.

Evaluation of multi-segmental kinematic modelling in the paediatric foot using three concurrent foot models

BackgroundVarious foot models are used in the analysis of foot motion during gait and selection of the appropriate model can be difficult. The clinical utility of a model is dependent on the repeatability of the data as well as an understanding of the expected error in the process of data collection. Kinematic assessment of the paediatric foot is challenging and little is reported about multi-segment foot models in this population. The aim of this study was to examine three foot models and establish their concurrent test-retest repeatability in evaluation of paediatric foot motion during gait.Methods3DFoot, Kinfoot and the Oxford Foot Model (OFM) were applied concurrently to the right foot and lower limb of 14 children on two testing sessions. Angular data for foot segments were extracted at gait cycle events and peaks and compared between sessions by intraclass correlation coefficient (ICC) with 95% confidence intervals (95%CI) and standard error of measurement (SEM).ResultsAll foot models demonstrated moderate repeatability: OFM (ICC 0.55, 95% CI 0.16 to 0.77), 3DFoot (ICC 0.47, 95% CI 0.15 to 0.64) and Kinfoot (ICC 0.43, 95% CI -0.03 to 0.59). On the basis of a cut-off of 5°, acceptable mean error over repeated sessions was observed for OFM (SEM 4.61° ± 2.86°) and 3DFoot (SEM 3.88° ± 2.18°) but not for Kinfoot (SEM 5.08° ± 1.53°). Reliability of segmental kinematics varied, with low repeatability (ICC < 0.4) found for 14.3% of OFM angles, 22.7% of 3DFoot angles and 37.6% of Kinfoot angles. SEM greater than 5° was found in 26.2% of OFM, 15.2% of 3DFoot, and 43.8% of Kinfoot segmental angles.ConclusionFindings from this work have demonstrated that segmental foot kinematics are repeatable in the paediatric foot but the level of repeatability and error varies across the segments of the different models. Information on repeatability and test-retest errors of three-dimensional foot models can better inform clinical assessment and advance understanding of foot motion during gait.

Foot loading patterns in normal weight, overweight and obese children aged 7 to 11 years.

BackgroundChildhood obesity is thought to predispose to structural foot changes and altered foot function. Little is currently understood about whether similar changes occur in overweight children. The aim of this study was determine foot loading characteristics in obese, overweight and normal weight children aged 7 to 11 years during level walking.MethodsDynamic plantar pressures were measured in 22 obese, 22 overweight and 56 normal weight children recruited from local primary and secondary schools in East London. Peak pressure, peak force, normalised peak force, pressure–time and force-time integrals were analysed at six regions of the plantar foot: lateral heel, medial heel, midfoot, 1st metatarsophalangeal joint, 2nd-5th metatarsophalangeal joint and hallux. A one-way ANOVA was used to test for significant differences in variables across the groups. Where differences existed Tukey post-hoc tests were used to ascertain the location of the difference.ResultsChildren who were obese and overweight demonstrated significantly (p<0.05) higher peak pressures and peak forces as well as significantly higher force-time and pressure–time integrals under the midfoot and 2nd-5th metatarsal regions. After normalisation of peak force, similar trends existed where the obese and overweight children demonstrated significantly (p<0.05) greater loading at the midfoot and 2nd-5th metatarsals.ConclusionFindings from this study indicated that overweight children, as young as seven, displayed differences in foot loading during walking, when compared with normal weight children. These findings were consistent with loading patterns of children who were obese and suggest that early assessment and intervention may be required in overweight children to mitigate against the development of musculoskeletal complications associated with excessive body mass.

Validation of the Hughston Clinic subjective knee questionnaire using gait analysis.

INTRODUCTION Subjective questionnaires, completed by the patient, are often used to document the status of a disabled knee. The purpose of this study was to validate the Hughston Clinic subjective knee questionnaire by describing how knee kinematics and kinetics correlated to subjective knee scores after knee injury and surgery. METHODS Five groups were studied: patients 2 (N = 37), 6 (N = 37), and 24 (N = 8) wk after ACL reconstruction (ACLR); patients with a chronic PCL deficiency (N = 9); and uninjured controls (N = 8). A three-dimensional motion analysis system and force platform were used to measure flexion angles and knee moments during level walking and stair climbing. RESULTS Hughston Clinic questionnaire scores were significantly correlated to mechanical descriptors measured during stair ascent and descent in the 2- and 6-wk ACLR groups (P < 0.05). The Hughston Clinic questionnaire score was correlated to several kinematic variables in the ACL reconstructed knee at 24 wk postoperative, e.g., knee flexion during walking. In the PCL deficient group, the Hughston Clinic questionnaire score was correlated with several kinetic measures, e.g., the peak moment (knee extensors). The Hughston Clinic questionnaire score was not correlated to knee mechanics in the control group. CONCLUSION The Hughston Clinic questionnaire score has been shown to be valid in this study as it reflects some mechanical descriptors during activities of daily living in the first 6 wk post ACL reconstruction. The questionnaire also provides information on gait modifications by people coping with knee injuries.

Comparison of muscle strength and in-vivo muscle morphology in young children with haemophilia and those of age-matched peers

Summary.  Recent advances in imaging have enhanced our understanding of the morphological adaptations of muscle in response to disease and altered use. Adaptation in muscle morphology has been linked to changes in muscle strength. To date, no studies have compared muscle morphology and strength in young children with haemophilia to that of typically developing children. This study explored differences in muscle strength and morphology between typically developing and age and size‐matched boys aged 6–12 years with haemophilia and a history of recurrent haemorrhage in the ankle joint. Maximum muscle strength of the knee flexors (KF), extensors (KE), ankle dorsi (ADF) and plantar flexors (APF) was measured in 19 typically developing boys (Group 1) and 19 boys with haemophilia (Group 2). Ultrasound images of vastus lateralis (VL) and lateral gastrocnemius (LG) were recorded to determine muscle cross‐sectional area (CSA), thickness, width, fascicle length and pennation angle. Muscle strength of the KE, ADF and APF were significantly (P < 0.05) lower in Group 2 when compared with Group 1. Muscle CSA and width of VL were significantly smaller and pennation angles significantly larger in Group 2 (P < 0.05). Muscle CSA and thickness of LG were significantly (P < 0.05) smaller in Group 2. Linear regression showed that LG muscle CSA and thickness were significant (P < 0.01) predictors of APF muscle strength. Following ankle joint bleeding in young boys with haemophilia, secondary adaptations in muscle strength and morphology were observed, suggesting that muscle function is more impaired than current clinical evaluations imply.