Safety and Efficacy of Early Rehabilitation With Assistance From a Single-Joint Hybrid Assistive Limb in Patients With Total Knee Arthroplasty: A Randomized Controlled Clinical Pilot Study.

Background This study aimed to evaluate the safety and effectiveness of knee exercise within four hours after total knee arthroplasty (TKA) using a single-joint hybrid assistive limb (HAL-SJ). Materials and methods This pilot single-blind randomized controlled trial included participants who underwent TKA for osteoarthritis and were randomly allocated to the early rehabilitation (n = 14) or control rehabilitation (n = 16) group. Knee rehabilitation exercises using the HAL-SJ began within four hours postoperatively in the early group and seven days after surgery in the control group. Knee circumference, range of motion (ROM), pain, muscle strength, and extension lag were assessed before and one and two weeks after surgery. Results Circumferences at 1 and 10 cm from the upper edge of the patella did not differ between the groups before surgery or one week postoperatively. The extension lag and knee flexion ROM after one week were significantly better in the early intervention group than in the control group. However, the quadriceps and hamstring isometric knee strength and pain scores did not differ between the groups at one and two weeks postoperatively. HAL-SJ-related complications were not reported. Conclusion Rehabilitation knee exercises using the HAL-SJ within four hours after TKA improved extension lag and knee flexion ROM without exacerbating knee swelling and pain.

Coper has altered foot joint coordination pattern compared to individuals with chronic ankle instability during running.

BACKGROUND: There is limited information regarding the cause for the different etiologies in individuals with initial lateral ankle sprains (LAS) who have chronic ankle instability (CAI) and no recurrence or instability for > 12 months (copers) following initial LAS. Assessing the movement patterns of copers and individuals with CAI and LAS recurrence is essential for identifying the mechanical factors that affect patient outcomes. RESEARCH QUESTION: Does coordination and coordination variability of rearfoot, midfoot, and forefoot present a potentially causative pattern for CAI or coper? METHODS: This cross-sectional study included 35 males who were divided into the CAI (n = 13), coper (n = 12), and control group (n = 10). Participants performed rearfoot strike running on the treadmill at a fixed speed of 3.5 m/s. The coupling angle between the rearfoot, midfoot, and forefoot, representing intersegmental coordination, was calculated using the modified vector coding technique and categorized into four coordination patterns. The coupling angle standard deviation served represented coordination variability during the stance phase. RESULTS: One control participant and one CAI participant were excluded, and final analyses were performed on the CAI (n = 12), coper (n = 12), and control (n = 9) groups. During late stance, the coper group showed a significantly greater proportion of in-phase with distal dominancy (p = 0.02, effect size=0.17) and a significantly lower proportion of in-phase with proximal dominancy (p = 0.05, effect size=0.17), than the CAI group. During the early stance, the coper group showed a significantly lower proportion of anti-phase with distal dominancy than the CAI group (p = 0.03, effect size=0.18). There were no differences in intra-foot variability among the groups. SIGNIFICANCE: The intra-foot coordination observed in the coper group suggests that this movement pattern may reduce the risk of ankle sprains.

Copers exhibit altered ankle and trunk kinematics compared to the individuals with chronic ankle instability during single-leg landing.

Copers are individuals who have had a lateral ankle sprain but have no history of recurrent lateral ankle sprain, residual symptoms, or functional disability. Copers have shown no significant difference in lower limb kinematics in landing for proactive conditions compared with a control (CTR) group. However, the copers (CPR) group has shown differences compared to CTR and chronic ankle instability (CAI) groups for dynamic balance conditions, suggesting that the trunk may compensate for foot instability during shock absorption. This study aimed to examine the differences in the kinematics and kinetics among CPR, CAI and CTR groups in reactive and proactive single-leg landing tasks. Participants were physically active adults with CAI (n = 14), CPR (n = 14), and CTR (n = 14), who performed proactive and reactive single-leg landings. The lower limb, trunk kinematics, vertical ground reaction force (vGRF) peak value, and the time to minimum peak vGRF were analysed. It might be conceivable that the CPR group could absorb vGRF efficiently by increasing the trunk flexion angle and increasing the time to reach the minimum peak vGRF regardless of landing condition. The results suggest that evaluating the movements of the entire body, including the ankle and trunk, is essential.

Copers adopt an altered dynamic postural control compared to individuals with chronic ankle instability and controls in unanticipated single-leg landing.

BACKGROUND: Several prior studies involving "expected" single-leg landings have not succeeded in establishing a difference between copers and a control group. RESEARCH QUESTION: Does expected and unanticipated single-leg landing affect dynamic postural stability in lateral ankle sprain individuals with chronic ankle instability (CAI), copers, and controls? METHODS: In this prospective cross-sectional study, physically active adults with CAI (n = 12), copers (n = 12), and controls (n = 12) were included. Participants performed expected single-leg landing by stepping off a 30-cm box. They also performed unanticipated landings including side-step cutting, side-step cutting at 60°, single-leg landing, and forward stepping. The expected and unanticipated conditions of each groups were compared in terms of time to stabilization (TTS) and center of pressure (COP) for the anterior-posterior (AP) and medial-lateral (ML) conditions. To analyze the data, a mixed-model one-way analysis of variance and a Tukey-Kramer post hoc test were performed. RESULTS: A significant condition × group interaction was observed in only TTS ML, with the CAI group demonstrating a significantly longer TTS ML than the coper (p < 0.001) and control (p < 0.001) groups during unanticipated trials. In addition, group interaction effects were observed for COP AP and TTS AP. The coper group demonstrated significantly longer COP AP and TTS AP than the control group (p < 0.001). SIGNIFICANCE: The CAI group demonstrated a significantly longer TTS ML than the coper and control groups during the unanticipated condition, and the coper group demonstrated significantly longer TTS AP and COP AP than the control group. Thus, longer COP AP and TTS AP sway time in the coper group may be a protection mechanism, allowing greater freedom in the AP plane while quickly controlling ML sway and preventing lateral ankle sprains. These findings can help in the prevention of lateral ankle sprains and assessment of dynamic postural control.

Individuals with chronic ankle instability exhibit altered ankle kinematics and neuromuscular control compared to copers during inversion single-leg landing.

OBJECTIVES: This study compares the ankle kinematics and muscle activities of the individuals with chronic ankle instability (CAI), coper, and control groups in normal and inversion single-leg landings. DESIGN: cross-sectional study; SETTING: Biomechanics laboratory. PARTICIPANTS: Physically active adults with CAI (N = 12); and coper (N = 12) and control (N = 12) groups. MAIN OUTCOME MEASURES: The participants performed normal and inversion single-leg landing. The muscle activity 200 ms before and after landing of the tibialis anterior, the medial gastrocnemius, and the fibularis longus (FL) were recorded. The FL latency, sagittal and frontal co-contraction indexes (CCI), ankle inversion angle at the initial contact, and the maximum inversion angle were recorded. RESULTS: Significantly longer FL latency, decreased FL muscle activity, frontal CCI, and an increased maximum inversion angle at post-landing were discovered during inversion single-leg landing in the CAI group compared to the coper and control groups. However, no significant difference was observed among the CAI and coper groups during normal single-leg landing. CONCLUSION: These results suggest prolonged FL latency and altered ankle kinematics suggest an increased risk of recurrent lateral ankle sprains in CAI with inversion single-leg landing.

Copers adopt an altered movement pattern compared to individuals with chronic ankle instability and control groups in unexpected single-leg landing and cutting task.

Individuals with chronic ankle instability (CAI) demonstrate altered ankle kinematics during landing compared to uninjured individuals. However, if copers may have adopted unique movement strategy to prevent repeated ankle sprains is unclear. The purpose of this study compares the lower-extremity joint kinematics and muscle activities of CAI (N = 8), coper (COP) (N = 8), and control (CON) (N = 8) groups in unexpected single-leg landing and cutting. Performance time (from initial contact to toe-off), number of mistakes in the jumping direction, low-extremity joint angle are assessed. Muscle activities were recorded from the tibialis anterior, medial gastrocnemius, and peroneus longus (PL), and mean muscle activity, co-contraction index (CI), and PL latency were analyzed. Results of performance time and CI are not significant. Significantly less number of mistakes in the jumping direction and a shorter PL latency were discovered in the COP and CON compared with the CAI group (P < 0.05). The peak hip joint flexion angle is significantly smaller in the COP than in the CON (P = 0.04). In dynamic tasks requiring quick judgments of ankle inclination, the COP may be able to accurately sense the inclination of the foot. Additionally, movement strategies differed between the COP and CON groups in an unexpected single-leg landing and cutting.