STUDY DESIGN: Case report. BACKGROUND: Decreased quadriceps activation has been shown to be present following anterior cruciate ligament (ACL) injury, but its presence prior to ACL injury is unknown. The purpose of this case report was to describe the level of quadriceps activation measured hours before a noncontact ACL injury in an individual who previously demonstrated known biomechanical risk factors for ACL injury. CASE DESCRIPTION: A 23-year-old female (height, 176.9 cm; mass, 72.4 kg), sustained a left noncontact ACL injury while landing from a jump stop during a recreational basketball game. This case was unique because data regarding landing biomechanics and quadriceps force and activation were gathered in 2 separate, unrelated studies prior to injury. OUTCOMES: Peak external knee abduction moment (-65.3 Nm) during a drop jump landing 8 months prior to injury indicated elevated risk for ACL injury. Involved quadriceps central activation ratios (CAR) were obtained 1 week (CAR, 0.81) and 4 hours (CAR, 0.77) prior to injury. Strength and CAR (0.76) measurements changed very little within 36 hours of injury and both strength, and activation (CAR, 0.90) improved following surgical reconstruction and formal rehabilitation. DISCUSSION: An individual with known biomechanical risk factors for ACL injury may compound risk for noncontact ACL injury if decreased quadriceps activation is also present. LEVEL OF EVIDENCE: Prognosis, level 4.

J Orthop Sports Phys Ther. 2008;38(8):502-507, published online 25 April 2008. doi:10.2519/jospt.2008.2761

KEY WORDS: ACL, biomechanics, knee, muscle inhibition

Objective:To compare changes in IM temperature during similar ultrasound treatments with 2 different coupling media. Background: Gel pads are gaining popularity as an ultrasound coupling medium. Intramuscular temperatures during ultrasound with gel pads and standard gel have not been compared.

Methods and Measures: Subjects were 13 student volunteers (21.3 ± 1.4 years of age) without lower-extremity pathology. Ultrasound treatments were administered in a laboratory on 2 separate occasions 48 hours apart, each with a different coupling medium (standard ultrasound gel or gel pad). One-MHz continuous ultrasound was administered for 7 minutes at 1.5 W/cm 2 with the transducer head moving 3 to 4 cm/s over an area approximately twice the size of the transducer head. Tissue temperature was measured every 10 seconds using implantable thermocouples inserted at a 3-cm depth to the surface of the right medial calf. Data were analyzed using an ANCOVA with pretreatment temperature as the covariate.

Results: Tissue temperatures increased during both treatments, with the mean and standard deviation peak temperature during the gel pad treatment reaching 39.4° ± 1.5°C compared to 39.2° ± 2.4°C during the normal gel treatment. Statistical analysis revealed no difference in temperature between ultrasound treatments using gel and those performed using gel pads.

Conclusions: Because temperature changes were similar with both treatments, we conclude that these coupling methods are equivalent under the ultrasound application parameters tested.

J Orthop Sports Phys Ther. 2002; 3(5):216–220.

Key Words: acoustic transmission, coupling medium, thermocouple

Study Design: Meta-analysis. Objective: To evaluate the effects of different types of ankle support on ankle and foot joint range of motion before and after activity using meta-analysis procedures. Background: The effects of ankle support on joint range of motion before and after exercise has been extensively studied, but the results among studies are not consistent. Obtaining knowledge from synthesizing the available literature with a meta-analysis can provide a greater understanding of these effects. Methods and Measures:A total of 253 cases from 19 studies were examined and included in this analysis. The treatment variables were ankle support with 3 levels (tape, lace-up, and semirigid) and time with 2 levels (before exercise and after exercise). Standardized effect sizes were computed for inversion, eversion, dorsiflexion, and plantar flexion range of motion to measure the difference between control and treatment groups at each point in time. Effect sizes were analyzed using a mixed-model factorial analysis of variance. Results: Before exercise, the semirigid condition (-2.97 ± 0.63) demonstrated greater restriction compared with the tape (-2.33 ± 0.38) and lace-up conditions (-2.18 ± 0.86) for inversion range of motion. After exercise, the semirigid condition (-3.85 ± 0.64) restricted inversion range of motion more than the tape (-1.07 ± 0.20) and lace-up (-1.56 ± 0.29) conditions. No differences were found between the mean effect sizes for the tape and lace-up conditions before and after exercise. With respect to eversion range of motion, the semirigid support (-2.69 ± 0.43) provided greater restraint compared with the tape (-1.00 ± 0.21) and lace-up (-1.40 ± 0.47) conditions. The lace-up condition also displayed greater support compared with tape alone. For dorsiflexion range of motion, greatest overall support was provided by the tape condition (-0.94 ± 0.06) compared with the lace-up condition (-0.51 ± 0.06). Conclusions: The greatest restriction of motion in the frontal plane was offered by the semirigid support condition, whereas taping offered the most support for limiting dorsiflexion range of motion. The results of this study may help clinicians make rational decisions concerning the selection of ankle appliances for preventing acute or chronic reinjury.

J Orthop Sports Phys Ther. 2000;30(4):170-182.

Key Words: ankle bracing, ankle injury, joint motion, meta-analysis

Hip exercises are frequently prescribed following knee injury and subsequent surgery based on the assumption that hip weakness exists. No data, however, are available that support hip weakness following knee trauma or surgery. Therefore, the purpose of this study was to compare hip strength in patients after knee surgery. Twenty-seven patients who had undergone unilateral knee surgery were tested for hip flexor, extensor, abductor, and adductor isometric strength prior to initiation of rehabilitation. Multivariate analysis of variance revealed significant hip weakness in all 4 hip muscle groups of the surgical extremities (11.9-25.3%, p=.05) when compared with nonsurgical extremities. Both peak and endurance force were affected. The greatest percent difference between the surgical and nonsurgical extremity occurred for hip extension peak (25.3%) and endurance (22.6%) force development. We recommend assessment of hip strength following knee surgery and appropriate resistive exercises if weakness exists.

J Orthop Sports Phys Ther. 1994;20(3):160-165.

Key Words: hip weakness, knee surgery, isometric force development