Knee joint instability is frequently reported by patients with knee osteoarthritis (KOA). Objective metrics to assess knee joint instability are lacking, making it difficult to target therapies aiming to improve stability. Therefore, the aim of this study was to compare responses in neuromechanics to perturbations during gait in patients with self-reported knee joint instability (KOA-I) versus patients reporting stable knees (KOA-S) and healthy control subjects.Forty patients (20 KOA-I and 20 KOA-S) and 20 healthy controls were measured during perturbed treadmill walking. Knee joint angles and muscle activation patterns were compared using statistical parametric mapping and discrete gait parameters. Furthermore, subgroups (moderate versus severe KOA) based on Kellgren and Lawrence classification were evaluated.Patients with KOA-I generally had greater knee flexion angles compared to controls during terminal stance and during swing of perturbed gait. In response to deceleration perturbations the patients with moderate KOA-I increased their knee flexion angles during terminal stance and pre-swing. Knee muscle activation patterns were overall similar between the groups. In response to sway medial perturbations the patients with severe KOA-I increased the co-contraction of the quadriceps versus hamstrings muscles during terminal stance.Patients with KOA-I respond to different gait perturbations by increasing knee flexion angles, co-contraction of muscles or both during terminal stance. These alterations in neuromechanics could assist in the assessment of knee joint instability in patients, to provide treatment options accordingly. Furthermore, longitudinal studies are needed to investigate the consequences of altered neuromechanics due to knee joint instability on the development of KOA.
PurposeEarly mobilization of critically ill patients improves functional recovery, but is often hampered by tubes, drains, monitoring devices and muscular weakness. A mobile treadmill with bodyweight support facilitates early mobilization and may shorten recovery time to independent ambulation as compared to usual care physiotherapy alone.Materials and methodsSingle center RCT, comparing daily bodyweight supported treadmill training (BWSTT) with usual care physiotherapy, in patients who had been or were mechanically ventilated (≥48 h) with ≥MRC grade 2 quadriceps muscle strength. BWSTT consisted of daily treadmill training in addition to usual care physiotherapy (PT). Primary outcome was time to independent ambulation measured in days, using the Functional Ambulation Categories (FAC-score: 3). Secondary outcomes included hospital length of stay and serious adverse events.ResultsThe median (IQR) time to independent ambulation was 6 (3 to 9) days in the BWSTT group (n = 19) compared to 11 (7 to 23) days in the usual care group (n = 21, p = 0.063). Hospital length of stay was significantly different in favour of the BWSTT group (p = 0.037). No serious adverse events occurred.InterpretationBWSTT seems a promising intervention to enhance recovery of ambulation and shorten hospital length of stay of ICU patients, justifying a sufficiently powered multicenter RCT.Trial registration number: Dutch Trial Register ID: NTR6943.
Background: A feasible and reliable instrument to measure strength in persons with severe intellectual and visual disabilities (SIVD) is lacking. The aim of our study was to determine feasibility, learning period and reliability of three strength tests.Methods: Twenty-nine participants with SIVD performed the Minimum Sit-to-Stand Height test (MSST), the Leg Extension test (LE) and the 30 seconds Chair-Stand test (30sCS), once per week for 5 weeks. Feasibility was determined by the percentage of successful measurements; learning effect by using paired t test between two consecutive measurements; test–retest reliability by intraclass correlation coefficient and Limits of Agreement and, correlations by Pearson correlations.Results: A sufficient feasibility and learning period of the tests was shown. The methods had sufficient test–retest reliability and moderate-to-sufficient correlations. Conclusion: The MSST, the LE, and the 30sCS are feasible tests for measuring muscle strength in persons with SIVD, having sufficient test re-test reliability.
The anterior cruciate ligament (ACL) is a strong rope-like tissue which connects the femur to the tibia in the knee joint. Its function is to provide structural stability to the knee while preventing unnatural forward movement of the tibia relative to the femur. Acute complete ACL ruptures during movements like knee hyperextension or sudden changes of direction (pivoting) damage two entities: the ligament itself and its nerve connections to the posterior tibial nerve (PTN). PTN innervation in the ACL is essential for: a) proprioception (e.g. perception of position and movement/acceleration experienced by the ligament), and b) stability of the knee joint. Upon ACL rupture, the orthopedic surgeon reconstructs the ACL with a graft from the hamstring, patellar or quadriceps tendon. After the surgery, the goal is to regain neuromuscular control and dynamic stabilization during rehabilitation as soon as possible for a quick return to sports and daily activities. However, surgeons are not able to reconstruct the nerve gap between the PTN and the grafted ligament due to the microscopic size of the innervation in the ACL. Not linking the PTN to the graft creates a disconnection between the knee joint and the spinal cord. To mitigate these disadvantages in ACL surgery, this study focuses on activating the growth of proprioception nerve endings using a ligament loaded with growth factors (neurotrophins). We hypothesize that neurotrophins will activate proprioceptive fibers of neurons close to the ACL. We describe graft fabrication steps and in vitro experiments to expand on the regeneration capacity of a commercially available ACL-like synthetic ligament called LARS. The results will bring the ACL regeneration field closer to having a graft that can aid patients in regaining mobility and stability during locomotion and running, confidence in the strength of the knee joint, and quick return to sports.
