Retention of kinematic patterns during a 6-minute walk test in people with knee osteoarthritis.

BACKGROUND: Knee osteoarthritis (OA) is a chronic condition affecting the entire joint and surrounding tissue, resulting in pain, stiffness and impaired movement. Recent studies have suggested the use of physical performance tests, such as the six-minute walk test (6MWT) to assess joint function for those with knee OA. This study assessed lower limb sagittal plane joint angles during a 6MWT for people with mild-moderate knee OA. METHODS: Thirty-one participants (18 male, 13 female; 62.9 ± 8.4 years) with knee OA were recruited. Gait data were collected in a single session during which participants completed a 6MWT around a 20 m course. Sagittal plane joint angles for the hip, knee and ankle were calculated during the first and last minute of the 6MWT. Statistical parametric mapping (SPM) was used to investigate changes in kinematic traces over the gait cycle. RESULTS: Mean joint angles for the hip and knee showed no significant differences between the first and last minute of the 6MWT. Ankle joint kinematic traces indicated there to be a decrease in plantarflexion approaching toe-off in the last minute of the test - a 1.5° reduction from the first minute. No significant differences were calculated for walking speed or joint range of motion. DISCUSSION: The lack of significant change in joint kinematic parameters and walking speed suggests the relative fatigue and pain burden to the participant over the duration of the 6-minute period is insufficient to elicit any mechanical changes to walking gait.

Changes in 24-Hour Physical Activity Patterns and Walking Gait Biomechanics After Primary Total Hip Arthroplasty: A 2-Year Follow-up Study.

BACKGROUND: Despite marked improvements in self-reported pain, perceived functional ability, and gait function following primary total hip arthroplasty (THA), it remains unclear whether these improvements translate into improved physical activity and sleep behaviors. The aim of this study was to determine the change in 24-hour activity profile (waking activities and sleep) and laboratory-based gait function from preoperatively to 2 years following the THA. METHODS: Fifty-one patients undergoing primary THA at a single public hospital were recruited. All THAs were performed using a posterior surgical approach with the same prosthesis type. A wrist-worn accelerometer was used to capture 24-hour activity profiles preoperatively and at 1 and 2 years postoperatively. Three-dimensional gait analysis was performed to determine changes in temporospatial and kinematic parameters of the hip and pelvis. RESULTS: Patients showed improvements in all temporospatial and kinematic parameters with time. Preoperatively, patients were sedentary or asleep for a mean time (and standard deviation) of 19.5 ± 2.2 hours per day. This remained unchanged up to 2 years postoperatively (19.6 ± 1.3 hours per day). Sleep efficiency remained suboptimal (<85%) at all time points and was worse at 2 years (77% ± 10%) compared with preoperatively (84% ± 5%). More than one-quarter of the sample were sedentary for >11 hours per day at 1 year (32%) and 2 years (41%), which was greater than the preoperative percentage (21%). Patients accumulated their activity performing light activities; however, patients performed less light activity at 2 years compared with preoperative levels. No significant differences (p = 0.935) were observed for moderate or vigorous activity across time. CONCLUSIONS: Together with improvements in self-reported pain and perceived physical function, patients had significantly improved gait function postoperatively. However, despite the opportunity for patients to be more physically active postoperatively, patients were more sedentary, slept worse, and performed less physical activity at 2 years compared with preoperative levels. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

3D modelling of tibial plateau fractures: Variability in fracture location and characteristics across Schatzker fracture types.

INTRODUCTION: Numerous classifications have been developed to assess tibial plateau fractures (TPF). Of these, the Schatzker system is the most widely reported in the literature yet this system is limited in its characterisation of morphological fracture features underlying the fracture location. The purpose of this study was to compare 3D morphological features of TPFs across different Schatzker types. METHODS: This study retrospectively analysed preoperative TPF imaging data to reconstruct 3D models of the fractures. Ninety-one fractures (29 female, 62 male) were analysed and classified using Schatzker. Fracture location across Schatzker types was compared based on division of the articular surface into six 'zones'. Additionally, morphological characteristics of the fractures were compared based on fracture type, including; the number, volume and shape of the fragments. RESULTS: Schatzker II, IV and VI fractures were most common, making up 41%, 16% and 20%, respectively. Type II fractures commonly involved both the lateral and central aspect of the tibial plateau, similarly, type IV fractures incorporated the lateral condyle in most cases. Considering the morphological metrics, statistically significant differences were observed between Schatzker types for the number of; total, articular, cortical and volumetrically significant (all P < 0.001) fragments along with the volume of both primary (P < 0.001) and secondary (P = 0.02) fragments. DISCUSSION: Assessment of underlying fracture characteristics in addition to fracture location can serve to provide greater detail relating to fracture morphology, which has the potential to assist with both surgical decision making and assessment of postoperative outcomes. Incorporating this information as part of a hierarchical or multifactorial framework for classifying fractures may help distinguish subtle differences between fracture types that are classifiable using the most current systems.

Postoperative lower limb joint kinematics following tibial plateau fracture: A 2-year longitudinal study.

BACKGROUND: The goal of postoperative tibial plateau fracture (TPF) management is to ensure surgical fixation is maintained while returning patients to normal function as soon as possible, allowing patients to resume their normal activities of daily living. The aim of this study was to investigate longitudinal changes in lower limb joint kinematics following TPF and determine how these kinematics relate to self-reported function. METHODS: Patients presenting with a TPF were recruited (n = 18) and undertook gait analysis at six postoperative time points (two weeks, six weeks, three months, six months, one and two years). Lower limb joint kinematics were assessed at each time point based on gait data. Statistical parametric mapping (SPM) was undertaken to investigate the change in joint kinematic traces with time. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was assessed at each time point to obtain self-reported outcomes. A healthy reference was also analyzed and used for qualitative comparison of joint kinematics. RESULTS AND SIGNIFICANCE: Knee kinematics showed improvements with time, however only minor changes were noted after six weeks at the hip, and six months at the knee and ankle relative to two weeks postoperative. SPM identified significant improvements with time in hip (p < 0.001) and knee (p = 0.003) flexion. No significant changes were observed with time at the ankle however, when compared to the healthy reference, participants showed reduced plantarflexion at two years. Lower limb joint ROM showed significant weak to moderate correlation with the ADL sub-scale of the KOOS (hip r = 0.442, knee r = 0.303, ankle r = 0.367). The lack of significant changes with time and overall reduced plantarflexion at the ankle potentially reduces propulsive capacity during gait up to two years postoperative. In this study, we see a deficiency in joint kinematics in TPF patients up to two years when compared to a healthy reference, especially at the ankle.

Longitudinal changes in lower limb joint loading up to two years following tibial plateau fracture.

BACKGROUND: Tibial plateau fractures are one of the most common intra-articular fractures resulting from high or low energy impact trauma. Few studies have assessed postoperative outcomes of these fractures with respect to changes in knee joint loading post-surgery. This gait analysis study compared lower limb joint loading up to two years post-surgery. METHODS: Twenty patients (range 27-67 years; 9:11(male:female)) were treated with open reduction internal fixation and instructed to weight bear as tolerated immediately following surgery. Joint loading at the hip, knee and ankle were assessed at six time points post-operatively up to two years. Gait analyses were performed at each time point and a musculoskeletal model was used to compute external joint moments for the lower limb. RESULTS: Hip flexion and extension (P = <0.001, P = <0.001), knee flexion (P = 0.014) and ankle plantarflexion moments (P = <0.001) showed significant increases with time. The hip flexion moment increased between six months and one year (mean difference = 0.16 Nm/kg) but did not increase thereafter (mean difference = 0.01 Nm/kg). Knee flexion and extension, and ankle plantarflexion moments increased up to six months (mean difference = 0.22 Nm/kg, 0.14 Nm/kg, 0.80 Nm/kg, respectively), but no further differences were seen with time from six months postoperative. DISCUSSION: The greatest changes in joint loads were observed at the hip and ankle within the first six months, likely a result of mechanical adaptations attempting to account for limited motion at the knee. Knee joint loading plateaued beyond six months suggesting functional outcomes are largely reliant on postoperative management within the initial three months while the bone is healing.

A systematic literature review of tibial plateau fractures: What classifications are used and how reliable and useful are they?

INTRODUCTION: Classification systems such as the Schatzker and AO/OTA have been proposed for standardised assessment of tibial plateau fractures and to guide clinical decision making. However, there has been no comprehensive literature review of all classification systems for tibial plateau fractures, including assessment of their reliability. The aim of this systematic review was to identify and appraise previously established classification systems for tibial plateau fractures and determine their reliability for fracture classification. METHODS: Six databases were searched from inception until October 2016. Classification systems for tibial plateau fractures were identified. No restriction was placed on imaging modality (plain film X-ray, CT, MRI). Data synthesis was performed to identify common features of the systems, their prevalence within the literature and studies of intra and inter-rater reliability of fracture classification using Kappa coefficient (κ). RESULTS: Thirty-eight classification systems were identified, five of which were a sub-classification of a single fracture type from a previous tool. The Schatzker and AO/OTA classification systems were the most commonly reported. Of the tools identified only five have been tested for inter and intra-observer reliability (Schatzker, AO/OTA, Duparc, Hohl and Luo). Reliability of more simplistic classification systems, such as that by Luo et al. (three-column) was typically high (intra-κ = 0.67-0.81, inter-κ = 0.71-0.87), but with the disadvantage of providing less information on fracture patterns and morphology. Intra and inter-observer reliability using plain film X-ray was frequently moderate (κ = 0.40-0.60), with 2D and 3D CT typically improving reliability of classification. Only 11 of the 32 complete classification systems identified association of fracture classification with clinical outcome. DISCUSSION: Frequently used systems for classification of tibial plateau fractures display moderate intra and inter-observer reliability. More sophisticated imaging modalities such as 2D and 3D CT typically improve reliability estimates. Using fracture classification based on imaging findings to predict clinical outcome was not a commonly reported goal of newly developed systems. More detailed assessment of fracture patterns and morphology, in conjunction with information on surgical fixation, may be desirable for predicting outcomes and to guide clinical decision making.