Assessment of knee flexor muscles strength in patients with patellar instability and its clinical implications for the non-surgical treatment of patients after first patellar dislocation - pilot study

Radiological Verification for the Suitability of Using the Quadriceps Angle to Represent Orientation of the Quadriceps Femoris

OBJECTIVES

The orientation of the quadriceps femoris can be represented by the quadriceps angle (Q-angle) has not yet been approved because of the high incidence of patellar instability. In this study, the correlations among components of the quadriceps femoris and the Q-angle using the plain radiographic technique were assessed. This retrospective study aims to use the radiographic technique to clarify these doubts from anatomic viewpoints.

METHODS

One hundred consecutive young adult patients (50 men and 50 women; aged, 34 ± 5 and 33 ± 6 years, respectively) who sustained chronic unilateral lower extremity injuries (unilateral femoral, tibial nonunions or malunions) were enrolled. The contralateral intact lower extremity was used for the study. The full-length standing scanogram (FLSS) was used to evaluate the rectus Q-angle (R-Q angle), vastus Q-angle (V-Q angle), and clinical Q-angle (C-Q angle; i.e., known as the Q-angle). The three Q-angles were compared statistically. The Mann-Whitney U test and the Kruskal-Wallis test were used for comparison among groups. The Spearman rank correlation coefficient was used to evaluate the degree of relationship between two groups.

RESULTS

The C-Q angle or the V-Q angle was statistically different from the R-Q angle (p < 0.001). The C-Q angle between sexes was not different (p = 0.25). High correlation occurred among the C-Q angle, the R-Q angle, and the V-Q angles (correlation coefficient, 0.886-0.979). The multiple linear regression revealed of C-Q angle = 0.72; R-Q angle, p < 0.001 + 0.21; and V-Q angle, (p = 0.009) + 2.61° in 100 patients.

CONCLUSION

Orientation of the quadriceps femoris can be represented by the Q-angle. Compared to the rectus femoris, the three vastus muscles of the quadriceps femoris are more correlated to the Q-angle.

Ebbing Strength, Fading Power: Unveiling the Impact of Persistent Fatigue on Muscle Performance in COVID-19 Survivors

The total number of confirmed cases of COVID-19 caused by SARS-CoV-2 virus infection is over 621 million. Post-COVID-19 syndrome, also known as long COVID or long-haul COVID, refers to a persistent condition where individuals experience symptoms and health issues after the acute phase of COVID-19. The aim of this study was to assess the strength and fatigue of skeletal muscles in people recovered from COVID-19. A total of 94 individuals took part in this cross-sectional study, with 45 participants (referred to as the Post-COVID Cohort, PCC) and 49 healthy age-matched volunteers (Healthy Control Cohort, HCC). This research article uses the direct dynamometry method to provide a detailed analysis of post-COVID survivors' strength and power characteristics. The Biodex System 4 Pro was utilized to evaluate muscle strength characteristics during the fatigue test. The fatigue work in extensors and flexors was significantly higher in the PCC. The PCC also showed significantly less power in both extensors and flexors compared to the HCC. In conclusion, this study provides compelling evidence of the impact of post-COVID-19 fatigue on muscle performance, highlighting the importance of considering these effects in the rehabilitation and care of individuals recovering from the virus. PCC achieved lower muscle strength values than HCC.

Association between single leg hop tests and patient reported outcome measures and patellar instability in patients with recurrent patellar dislocations

Objectives

To assess the associations between the single leg hop tests at two premises; baseline and the change after 12 months, and change in patient reported outcome measures and persistent instability after 12 months in patients with recurrent lateral patellar dislocation (RLPD).

Methods

61 RLPD patients aged 12-30 with a mean (±SD) of 19.2 (±5.3) were assessed at baseline, and at 12 months after treatment with either active rehabilitation alone, or medial patellofemoral ligament reconstruction and active rehabilitation. Single leg hop for distance, triple hop for distance, crossover hop for distance and 6-metre timed hop were performed for both legs, and the Limb Symmetry Index (LSI) was calculated. Persistent patellar instability was self-reported as 'Yes' or 'No' at 12-month follow-up. Knee function in sport and recreational activities and knee-related quality of life were assessed at baseline and 12 months follow-up using the Knee injury and Osteoarthritis Outcome Score (KOOS).

Results

LSI for the baseline single leg hop for distance and the triple hop for distance was significantly associated with persistent patellar instability at 12 months follow-up with an OR of 0.94 (95% CI 0.88 to 0.99) and OR of 0.91 (95% CI 0.84 to 0.99), respectively. No other statistically significant associations were detected.

Conclusion

Individuals with higher LSI values for the single leg hop for distance and triple hop for distance conducted at baseline had lower odds for persistent patellar instability at 12 months follow-up. Clinicians can use results from these hop tests to assess the risk of future recurrent patellar instability prior to treatment.

Study design

Retrospective cohort study.

Trial registration number

NCT02263807.