Alignment and soft tissue (ligament) balance are two variables that are under the control of a surgeon during replacement arthroplasty of the knee. Mobile bearing medial unicompartmental knee replacements have traditionally advocated sizing the prosthesis based on soft tissue balance while accepting the natural alignment of the knee, while fixed bearing prosthesis have tended to correct alignment to a pre planned value, while meticulously avoiding overcorrection. The dynamic loading parameters like peak adduction moment (PKAM) and angular adduction Impulse (Add Imp) have been studied extensively as proxies for medial compartment loading. In this investigation we tried to answer the question whether correcting static alignment, which is the only alignment variable under the control of the surgeon actually translates into improvement in dynamic loading during gait. We investigated the effect of correction of static alignment parameter Hip Knee Ankle (HKA) angle and dynamic alignment parameter in coronal plane, Mean Adduction angle (MAA) on 1st Peak Knee Adduction Moment (PKAM) and Angular Adduction Impulse (Add Imp) following medial unicompartmental knee replacements. Twenty four knees (20 patients) underwent instrumented gait analysis (BTS Milan, 12 cameras and single Kistler force platform measuring at 100 Hz) before and after medial uni compartmental knee replacement. The alignment was measured using long leg alignment views, to assess Hip Knee Ankle (HKA) angle. Coronal plane kinetics namely 1st Peak Knee Adduction Moment (PKAM) and angular adduction impulse (Add Imp)- which is the moment time integral of the adduction moment curve were calculated to assess medial compartment loading. Single and multiple regression analyses were done to assess the effect of static alignment parameters (HKA angle) and dynamic coronal plane alignment parameters (Mean Adduction Angle – MAA) on PKAM and Add Imp.Background
Methods
Department of Epidemiology, ASL RM/E, Rome, Italy School of Health and Social Care, University of Teesside, Middlesbrough, UK Faculty of Health, Staffordshire University, Stoke on Trent, UK Orthopaedic and Trauma Department, “Tzanio” General Hospital of Piraeus, Greece University of Medical Sciences, Poznan, Poland Department of Orthopaedic Surgery, Saitama Medical University, Kawagoe, Japan Thriasio General Hospital, Athens, Greece To evaluate the efficacy of bracing in adolescent patients with AIS. Cochrane systematic review The following databases were searched with no language limitations: the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINHAL and reference lists of articles. Extensive hand searching of grey literature was also conducted. RCT's and prospective cohort studies comparing braces with no treatment, other treatment, surgery, and different types of braces were included. Two review authors independently assessed trial quality and extracted data. Two studies were included. There was very low quality evidence from one prospective cohort study including 286 girls1indicating that braces curbed curve progression, at the end of growth, (success rate 74%), better than observation, (34%) and electrical stimulation (33%). Another low quality evidence from one RCT with 43 girls indicated that a rigid brace is more successful than an elastic one (SpineCor) at limiting curve progression when measured in Cobb degrees2. No significant differences between the two groups in the subjective perception of daily difficulties associated with brace wearing were found. There is very low quality evidence in favour of using braces, making generalization very difficult. The results from future studies may differ from these results. In the meantime, patients' choices should be informed by multidisciplinary discussion. Future research should focus on short and long-term patient-centred outcomes as well as measures such as Cobb angles. RCTs and prospective cohort studies should follow both the SRS and the Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) criteria for bracing studies.
While previous studies have highlighted possible aetiological factors for adolescent idiopathic scoliosis (AIS), research employing gait measurements have demonstrated asymmetries in the ground reaction forces, suggesting a relationship between these asymmetries, neurological dysfunction and spinal deformity. Furthermore, investigations have indicated that the kinematic differences in various body segments may be a major contributing factor. This investigation, which formed part of a wider comprehensive study, was aimed at identifying asymmetries in lower limb kinematics and pelvic and back movements during level walking in scoliotic subjects that could be related to the spinal deformity. Additionally, the study examined the time domain parameters of the various components of ground reaction force together with the centre of pressure (CoP) pattern, assessed during level walking, which could be related to the spinal deformity. Although previous studies indicate that force platforms provide good estimation of the static balance of individuals, there remains a paucity of information on dynamic balance during walking. In addition, while research has documented the use of CoP and net joint moments in gait assessment and have assessed centre of mass (CoM)–CoP distance relationships in clinical conditions, there is little information relating to the moments about CoM. Hence, one of the objectives of the present study was to assess and establish the asymmetry in the CoP pattern and moments about CoM during level walking and its relationship to spinal deformity. The investigation employed a six camera movement analysis system and a strain gauge force platform in order to estimate time domain kinetic parameters and other kinematic parameters in the lower extremities, pelvis and back. 16 patients with varying degrees of deformity, scheduled for surgery within a week took part in the study. The data for the right and left foot was collected from separate trials of normal walking. CoP was then estimated using the force and moment components from the force platform. Results indicate differences across the subjects depending on the laterality of the major curve. There is an evidence of a relationship between the medio-lateral direction CoP and the laterality of both the main and compensation curves. This is not evident in the anterior-posterior direction. Similar results were recorded for moments about CoM. Subjects with a higher left compensation curve had greater deviation to the left. Furthermore, the results show that the variables identified in this study can be applied to initial screening and surgical evaluation of spinal deformities such as scoliosis. Further studies are being undertaken to validate these findings.