Background and objectives: Anterior cruciate ligament reconstruction (ACLR) often results in quadricep atrophy. The purpose of this study was to compare the bilateral thickness of each quadricep component before and after ACLR. Materials and Methods: Cross-sectional study design. In 14 patients who underwent ACLR, bilateral quadricep muscle thicknesses were measured using a portable ultrasound device, 1 h before and 48–72 h after ACLR. Two-way analysis of variance (ANOVA) was used to compare muscle thickness pre- and post-ACLR between the limbs. Results: The primary finding was that the vastus intermedius (VI) muscle was significantly smaller in the reconstructed limb after ACLR compared to that in the healthy limb (Reconstructed limb; RCL = Pre-operated (PRE): 19.89 ± 6.91 mm, Post-operated(POST): 16.04 ± 6.13 mm, Healthy limb; HL = PRE: 22.88 ± 6.07, POST: 20.90 ± 5.78 mm, F = 9.325, p = 0.009, η2p = 0.418). Conclusions: The results represent a selective surgical influence on the quadricep muscle thickness. These findings highlight the need of advanced strengthening exercises in order to restore VI thickness after ACLR.

This study aimed to compare immediate changes in the thickness of the rectus femoris (RF), vastus intermedius (VI), vastus lateralis (VL), vastus medialis (VM), and vastus medialis oblique (VMO) muscles after open kinetic chain exercise (OKCE) and closed kinetic chain exercise (CKCE) and identify the effect of both exercise types on each quadricep muscle for early rehabilitation to prevent knee joint injury. Twenty-six healthy participants (13 males and 13 females) were randomly divided into the OKCE (n = 13) and CKCE (n = 13) groups. The thickness of their quadriceps muscles was measured using a portable ultrasonic imaging device before and after exercise in the sequence RF, VI, VL, VM, and VMO. A two-way repeated measures analysis of variance was used to compare the thickness of each component of the quadriceps muscles between the two groups. The thickness of the RF, VL, VM, and VMO muscles increased after OKCE, and the thickness of the VI muscle showed the greatest increase with a medium–large effect size (F = 8.52, p = 0.01, and d = 0.53). The thickness of the VI, VL, VM, and VMO muscles increased after CKCE, and the VMO muscle had the largest effect size (F = 11.71, p = 0.00, and d = 1.02). These results indicate that the thickness of the quadriceps muscles can be selectively improved depending on the type of exercise.

PURPOSE: The purpose of this study was to examine the inter-rater reliability of a portable ultrasound device for measuring the muscle thickness of the quadriceps and hamstrings in healthy subjects.METHODS: Thirty-six subjects (20 males, 16 females, age 22.2±2.0 years, mass 67.4±11.3 kg, height 171.7±9.6 cm) participated as subjects and two examiners attended. The thickness of the quadriceps was measured in order of rectus femoris (RF), vastus intermedius (VI), vastus lateralis (VL), vastus medialis (VM), and vastus medialis oblique (VMO). The hamstring thickness was measured in order of biceps femoris (BF), semitendinosus (ST), and semimembranosus (SM). Three measurements were taken for each muscle by one examiner. Using image J software, the average thickness was calculated from the measured image. Pearson’s correlation coefficient was used in order to identify inter-rater reliability, and the statistical significance level was set to <i>p</i><.05.RESULTS: Pearson correlation coefficient for inter-examiner reliability of ultrasound showed moderate-to-high level for all assessed muscle. In quadriceps, the values were significantly correlated ranged from 0.62 to 0.90 and in hamstrings the value were relatively low with values of 0.57 to 0.68.CONCLUSIONS: The findings of this study indicated that portable ultrasound was a reliable method for measuring the quadriceps and hamstring muscle thickness. Therefore, it could be used as a useful assessment tool in future studies to assess various skeletal muscle thicknesses.

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