Balance Evaluation and Gait Analysis After Arthroscopic Partial Meniscectomy

Medial meniscus injury changed plantar pressure distributions and decreased posture stability especially in those with varus alignment: a cross-sectional study based on a wearable smart plantar pressure system

BACKGROUND

Medial meniscus (MM) injuries are common and often contribute to knee osteoarthritis (KOA). While studies focus on joint degeneration, the role of extrinsic factors such as postural control remains underexplored. This study investigated how MM injuries affected postural control, particularly plantar pressure distribution, with an emphasis on lower limb alignment.

METHODS

83 participants were recruited: 29 healthy subjects, 29 MM patients with neutral alignment (-3°< hip-knee-ankle angle (HKA) ≤ 3°), and 25 MM patients with varus alignment (HKA > 3°). Plantar pressure was measured using a shoe-integrated detection system. Normalized peak force, center-of-pressure (COP), and time-to-boundary (TTB) were measured during walking and single-leg stance (SLS).

RESULTS

During walking, compared to the healthy group, the varus alignment group showed lower peak force for the posterior heel (P = 0.012), lateral midfoot (P = 0.024) and hallux (P = 0.009). When the two sides were compared, the varus group exhibited a lower peak force in the anterior heel (P = 0.004) and hallux (P = 0.017) of the affected sides, the neutral (P = 0.043) and varus (P = 0.045) groups all showed higher medio-lateral COP of the unaffected sides, indicating the COP shifting laterally. In SLS test, the two MM groups demonstrated increased peak force of the third (P = 0.037) and fifth (P = 0.040) metatarsals compared to the healthy group, the peak force of the posterior heel were lower in the varus alignment group compared to the healthy group (P = 0.007) and the neutral alignment group (P = 0.008). And the TTB absolute value of medial-lateral direction of the two MM groups were lower than healthy controls (P = 0.029). The area under the receiver operating characteristic curve (AUC = 0.698, P = 0.016) suggested that peak force of posterior heel had good performance to discriminate varus alignment group from neutral alignment group.

CONCLUSION

MM injuries, especially with varus alignment, lead to significant changes in plantar pressure distribution and postural stability. These insights are clinically significant for designing early, biomechanically-informed rehabilitative strategies to optimize recovery and prevent further joint degeneration following MM injuries.

The effects of sleep deprivation on the balance system: following normal sleep, 24 h of sleep deprivation, and rest under eyes-open and eyes-closed conditions

OBJECTIVE

This study investigated the effects of sleep deprivation (SD) on balance after normal sleep, 24 h of SD, and subsequent rest under eyes-open (EO) and eyes-closed (EC) conditions. Our aim was to ascertain whether the reduced efficiency of balance control following SD is generalized or selective.

METHOD

Nineteen participants (12 females, 7 males) completed the Pittsburgh Sleep Quality Index (PSQI). The mean ages for male participants were 24.14 ± 0.37 years, their height was 180.71 ± 5.46 cm, and weight of male participants were 81.71 ± 13.42 kg. For female participants, the mean ages were 24.41 ± 4.01 years, their height was 163.66 ± 2.64 cm, and their weight was 59.54 ± 9.18 kg. Stance analyses were conducted after normal sleep, 24 h of SD, and subsequent rest of both the EO and EC. Participants performed a normal balance test, a second test while holding cubes and counting backwards from 200 by sevens, and a third test after rest under EO and EC.

RESULTS

Independent samples t-tests showed significant height and weight differences between sexes (p < 0.05), with females generally smaller. No significant differences were found in age, daytime sleep duration, or PSQI score (p > 0.05). Significant differences in parameters such as length of the minor axis (lomna), angle, and area were observed in EO and EC across the three days, revealing the interplay between visual stimuli, cognitive tasks, and parameter stability.

CONCLUSION

SD has multifaceted impacts on motor and cognitive performance, even when attentional and sensory resources are not strained. Our findings elucidate the nuanced impact of SD on cognitive performance, and suggest the efficacy of external factors in mitigating its effects on postural control.

Late-Onset Femoroacetabular Impingement Syndrome Following Knee Arthroscopy in a Retrospective Cohort

Background/Objectives: Hip-knee coupling is a well-documented phenomenon, and interventions to one joint can alter biomechanics at the other. The purpose of this study was to investigate if knee surgery is associated with later onset of femoroacetabular impingement syndrome (FAIS). Methods: A retrospective chart review was conducted regarding patients at a single academic institution who underwent hip arthroscopy for FAIS between January 2011-October 2021. Patient charts were queried for past surgical history of knee arthroscopy before hip arthroscopy. Patients who previously underwent hip arthroscopy with no history of knee arthroscopy served as controls. Details about demographics and the onset of hip symptoms were abstracted from patient charts. Statistical analysis was conducted using Mann-Whitney testing and binary logistic regression. Results: Of the 1569 patients identified, 127 had a history of knee arthroscopy and reported no hip symptoms at or prior to the time of surgery. Patients who had undergone prior knee arthroscopy were significantly older at onset of initial hip symptoms (42.15 ± 11.80 years versus 34.62 ± 12.49 years, p < 0.001) and at the time of hip arthroscopy (44.12 ± 11.85 years versus 36.90 ± 12.14 years, p < 0.001) when controlling for age, sex, and BMI. These patients first developed hip symptoms at a mean of 8.57 ± 8.53 years following knee arthroscopy (median 6.10 years) and underwent operative treatment 1.76 ± 1.96 years later. Conclusions: Patients with a history of prior knee arthroscopy are older at the time of hip symptom onset and subsequent hip arthroscopy for the treatment of FAIS.

A combined musculoskeletal and finite element model of a foot to predict plantar pressure distribution

In this study, a combined subject-specific numerical and experimental investigation was conducted to explore the plantar pressure of an individual. The research utilized finite element (FE) and musculoskeletal modelling based on computed tomography (CT) images of an ankle-foot complex and three-dimensional gait measurements. Muscle forces were estimated using an individualized multi-body musculoskeletal model in five gait phases. The results of the FE model and gait measurements for the same subject revealed the highest stress concentration of 0.48 MPa in the forefoot, which aligns with previously-reported clinical observations. Additionally, the study found that the encapsulated soft tissue FE model with hyper-elastic properties exhibited higher stresses compared to the model with linear-elastic properties, with maximum ratios of 1.16 and 1.88 MPa in the contact pressure and von-Mises stress, respectively. Furthermore, the numerical simulation demonstrated that the use of an individualized insole caused a reduction of 8.3% in the maximum contact plantar pressure and 14.7% in the maximum von-Mises stress in the encapsulated soft tissue. Overall, the developed model in this investigation holds potential for facilitating further studies on foot pathologies and the improvement of rehabilitation techniques in clinical settings.