STUDY DESIGN: Experimental laboratory study. OBJECTIVES: To measure the transmission of dexamethasone sodium phosphate (DEX-P) using iontophoresis as a function of skinfold tissue thickness and time elapsed between treatment and tissue extraction. BACKGROUND: Iontophoresis is a modality used in physical therapy with the intent to drive medications through the skin to underlying tissues using a direct electrical current. DEX-P is the most commonly used medication with iontophoresis and is used to treat a variety of connective tissue conditions. METHODS AND MEASURES: Sixteen adults undergoing anterior cruciate ligament reconstructive surgery using the semitendinosis/gracilis autograft received a 40-mA-min dose of iontophoresis with 0.4% DEX-P superficial to a slip of the distal semitendinosis tendon prior to surgery. The tendon slip was extracted within 4 hours. Time between treatment and tissue extraction and skinfold thickness were measured. Analysis was performed on the slip of the semitendinosis using high-performance liquid chromatography mass spectrum. RESULTS: Of the 16 subjects (10 female, 6 male; mean age, 33 years), 7 had measurable amounts of DEX-P in the tendon slip (4 female, 3 male; mean age, 34 years). The average concentration in the 16 subjects was 2.9 ng/g of tendon tissue. There was no correlation between DEX-P absorbed and skinfold thickness (r = –0.08, P = .79) or time elapsed (r = 0.25, P = .38). In a subset of the 7 individuals that showed measurable levels of DEX-P absorbed, the average concentration of DEX-P was 6.6 ng/g of tendon tissue, and there was a relationship between DEX-P concentrations and time elapsed that did not reach statistical significance (r = 0.71, P = .11). CONCLUSIONS: Iontophoresis appears to facilitate the transmission of dexamethasone to connective tissues in humans with skinfold thickness up to at least 30 mm. The absorption of the dexamethasone seemed to continue to occur for up to 4 hours after delivery. It is not clear why DEX-P was measured in only 7 of the 16 subjects. LEVEL OF EVIDENCE: Therapy, level 5.

J Orthop Sports Phys Ther. 2008;38(5):238-245, published online 22 January 2008. doi:10.2519/jospt.2008.2648 

KEY WORDS: connective tissue, pain, tendinitis

STUDY DESIGN: Experimental laboratory study. OBJECTIVES: We tested the hypothesis that the muscle fibers and the connective tendinous structures, combined in series, provide the resistance to passive joint movement at the ankle. We also determined the relative association between passive joint torque and each of these 2 elements. BACKGROUND: The reason for individual variation in joint flexibility or tightness is not clearly understood, but the influence of musculotendinous stiffness has been inferred. METHODS AND MEASURES: Each of the subjects (6 women and 6 men) was seated with the right knee extended and right ankle positioned at a 30°, 20°, 10°, 0°, –10°, –20°, and –30° (0, neutral position, positive values reflecting plantar flexion) angle while passive plantar flexion torque was measured. The distal muscle-tendon junction of the medial gastrocnemius was visualized by ultrasonography, and its positional change was defined as muscle belly length change. The whole muscle-tendon unit length change was estimated from joint angle changes, from which Achilles tendon length change was estimated. RESULTS: Both the muscle belly and tendon were significantly elongated as the ankle was dorsiflexed (at 0° the mean ± SD muscle belly elongation was 10.3% ± 1.8 %, and the tendon elongation was 2.8% ± 1.2 %, of the initial length at 30° of ankle plantar flexion), from which stiffness indices were determined both for muscle belly and tendon. The passive torque at 0°, –10°, –20°, and –30° was significantly correlated with the stiffness indices of the Achilles tendon (at 0°, r² = 0.70 and 0.62 for overall and specific stiffness, respectively; P<.05). A tendon stiffness index, separately obtained from tendon lengthening during maximal isometric contraction, was also correlated with passive ankle plantar flexion torque at 0°, –10°, –20°, and –30° (at 0°, r² = 0.76; P<.05). The specific stiffness index of the muscle belly was correlated (r² = 0.47, P<.05) with the passive ankle plantar flexion torque at 0°, but its overall stiffness index was not (r² = 0.32, P>.05). CONCLUSION: Results suggest that extensibility of the muscle-tendon unit of the Achilles tendon for the most part is related to passive ankle plantar flexion joint torque.

J Orthop Sports Phys Ther. 2008;38(5):269-276, published online 22 January 2008. doi:10.2519/jospt.2008.2632

SYNOPSIS: The number of total knee arthroplasty (TKA) surgeries performed each year is predicted to steadily increase. Following TKA surgery, self-reported pain and function improve, though individuals are often plagued with quadriceps muscle impairments and functional limitations. Postoperative rehabilitation approaches either are not incorporated or incompletely address the muscular and functional deficits that persist following surgery. While the reason for quadriceps weakness is not well understood in this patient population, it has been suggested that a combination of muscle atrophy and neuromuscular activation deficits contribute to residual strength impairments. Failure to adequately address the chronic muscle impairments has the potential to limit the long-term functional gains that may be possible following TKA. Postoperative rehabilitation addressing quadriceps strength should mitigate these impairments and ultimately result in improved functional outcomes. The purpose of this paper is to describe these quadriceps muscle impairments and discuss how these impairments can contribute to the related functional limitations following TKA. We will also describe the current concepts in TKA rehabilitation and provide recommendations and clinical guidelines based on the current available evidence. LEVEL OF EVIDENCE: Therapy, level 5.

J Orthop Sports Phys Ther. 2008;38(5):246-256, published online 14 December 2007. doi:10.2519/jospt.2008.2715

STUDY DESIGN: Controlled laboratory study. OBJECTIVE: To compare postural performance measures of athletes with those of nonathletes when completing the standard Sensory Organization Test (SOT) and a modified SOT that included dynamic head tilts (DHT-SOT). BACKGROUND: Authors of recently published research have suggested that modifications to the SOT protocol (eg, introduction of pitch and roll head tilts) may enhance the test's sensitivity when assessing postural stability in individuals with higher balance capabilities or with well-compensated sensory deficits. METHODS AND MEASURES: Nineteen athletes and 19 nonathletes (group) completed both the SOT and DHT-SOT (protocol). During the SOT, participants stood upright as steadily as possible for 20 seconds during each of 6 different sensory conditions. As a variation of the SOT, the DHT-SOT incorporated active pitch and roll head tilts into the SOT protocol. Four 2-way mixed-model analyses of variance (with protocol as the repeated factor) were performed to determine if the composite equilibrium score or the visual, vestibular, or somatosensory ratio scores differed between the 2 groups across the 2 testing protocols. RESULTS: Significant group-by-protocol interaction effects were present for both the composite equilibrium score and visual ratio. Follow-up simple main-effects analyses indicated that these measures did not differ between groups for the SOT protocol but were significantly different on the DHT-SOT. CONCLUSIONS: The addition of dynamic head tilts to the SOT protocol resulted in subtle differences in balance function between athletes and nonathletes. Athletes demonstrated an increased ability to adapt to sensory disruptions during the DHT-SOT. Therapists should consider including active pitch and roll head tilts to the SOT when evaluating individuals with higher balance function or to detect subtle deficits in balance function. LEVEL OF EVIDENCE: Diagnosis, level 3b.

J Orthop Sports Phys Ther. 2008;38(5):262-268, published online 12 March 2008. doi:10.2519/jospt.2008.2406

The patient was a 44-year-old male with a 5-month history of lumbar radiculopathy following a golf injury. Following magnetic resonance imaging, he received a spinal epidural injection consisting of corticosteriods from his spine surgeon 2 weeks prior to physical therapy evaluation. Five weeks postinjection, the patient noted a progressive and significant worsening of his local lumbar and radicular symptoms. Magnetic resonance imaging revealed a lumbar subcutaneous abscess, for which the patient underwent open debridement and intravenous antibiotic therapy for methicillin sensitive staphylococcus aureus. He subsequently returned to physical therapy for successful management of his residual disablement.

J Orthop Sports Phys Ther., 2008;38(5):287. doi:10.2519/jospt.2008.0405

KEY WORDS: infection, magnetic resonance imaging, staphylococcus aureus