The biophysical effects of ultrasound on median nerve distal latencies.

PURPOSE: Previous studies have documented the lack of ultrasound's non-thermal effects on nerve conduction using frequencies of 1 MHz and 870 kHz. The analyses and conclusions were reached, despite only one study incorporating pulsed ultrasound. The purpose of this study was to determine the biophysical effects of continuous wave (CW) and pulsed wave (PW) ultrasound on median nerve motor and sensory latencies using common frequencies of 1.0 and 3.0 MHz. SUBJECTS: Fifteen healthy subjects (8 males, 7 females, age = 23.5 + 4.44 yrs, height = 171.2 + 10.7 cm, weight = 67.5 + 7.9 kg) without a history of neurological or musculoskeletal injury to their non-dominant arm volunteered for testing. METHODS AND MATERIALS: Subjects were exposed in counterbalanced order to five ultrasound treatment conditions: (1) 1 MHz, 1.0 W/cm2, 8 min., (2) 1 MHz, 1.0 W/cm2, 50% PW, 8 min., (3) 3.0 MHz, 1.0 W/cm2, CW, 8 min., (4) 3.0 MHz, 1.0 W/cm2, 50% PW, 8 min., (5) placebo, 0.0 W/cm2, 8 min. Dependent measures for motor and sensory latencies, and subcutaneous temperatures were taken pretreatment, at 2, 4 and 6 minutes during treatment, and immediately post-treatment. Separate two within repeated measures ANOVA were used for each dependent measure. RESULTS: Analysis revealed significant interactions for motor latencies [F (16,224) = 52.77, p < .001], sensory latencies [F (16,224) = 41.10, p < .001], and subcutaneous temperatures [F (16,224) = 52.77, p < .001]. Tukey's HSD post hoc analyses confirmed that nerve latencies responded similarly to subcutaneous temperature changes during and after ultrasound treatment. CONCLUSIONS: Alterations in nerve latencies from ultrasound on healthy nerves appeared to be related to temperature changes induced by ultrasound's thermal effects, and not by non-thermal or mechanical effects.

Evaluation of the injured wrist on the field and in the office.

The wrist is a common site of injury in sports, both acute and chronic. Evaluation of wrist injuries requires knowledge of anatomy kinematics, attention to the mechanism of injury, the intensity of training, and a focus on the physical examination for specific injuries.

Reliability and responsiveness of disablement measures following acute ankle sprains among athletes.

The minimum amount of change which represents clinical improvement following ankle sprains is unknown. This study considers the usefulness of physiological and behavioral measures commonly employed for this purpose in sports rehabilitation settings. Thirteen collegiate athletes of both genders were measured at approximately 3 and 10 days post-grade I or II ankle sprain. Volumetric displacement and sagittal plane ankle range of motion measures were used as impairment indicators. Motor ability scores (activity count) and a perceived athletic ability measure (visual analog scale) were used to indicate functional limitations. Volumetric displacement and both functional limitation measures demonstrated responsiveness to change between two occasions of measurement separated by 1 week. Observed changes in range of motion deficits could not be distinguished from measurement error. The results of this study suggest that behavioral measures of motor activity and perceived athletic ability may be at least as useful as physical measures of organic dysfunction for assessing clinical improvement following acute ankle sprains among athletes.

Temperature changes in deep muscles of humans during upper and lower extremity exercise.

OBJECTIVE: To examine the effect of 15 minutes of upper and lower extremity exercise on raising intramuscular temperature in the triceps surae to 39 degrees C to 45 degrees C (the therapeutic range). DESIGN AND SETTING: Intramuscular temperature was measured 5 cm deep in the triceps surae using a 23-gauge thermistor needle microprobe connected to a monitor. Each subject was tested under 3 conditions: 15 minutes of rest, 15 minutes of jogging on a treadmill, and 15 minutes of handpedaling an upper-body ergometer. Exercise bouts were performed at 70% of each subject's maximum heart rate. SUBJECTS: Six males, either sedentary or recreational athletes (age = 21.3 +/- 2.9 years; ht = 176.8 +/- 6.0 cm; wt = 72.7 +/- 11.6 kg; resting heart rate = 57.8 +/- 6.74 bpm; target heart rate = 156.5 +/- 3.0 bpm), volunteered to participate in this experiment. MEASUREMENTS: Intramuscular temperature was measured at a depth of 5 cm before and after each test condition. RESULTS: Data analyses consisted of analyses of variance with repeated measures and a Tukey post hoc test (P < .05). The results showed a significant temperature increase over baseline after exercise on the treadmill (2.2 degrees C +/- 0.63 degrees C); however, it did not yield temperature increases >/= 39 degrees C. No significant temperature change occurred after exercise on the upper-body ergometer (-0.45 degrees C +/- 0.80 degrees C). CONCLUSIONS: Active exercise increased intramuscular temperature in working muscles but did not affect intramuscular temperature in nonworking muscles. In addition, 15 minutes of jogging on a treadmill at 70% of maximum heart rate was not sufficient to raise intramuscular temperature to 39 degrees C to 45 degrees C.

Anterior cruciate ligament reconstruction and joint dynamics during stair climbing.

Athletes with anterior cruciate ligament (ACL) deficiencies exert decreased knee extension moments during level walking (quadriceps avoidance gait), and yet within a few months of ACL reconstruction they are often expected to return to competitive sport. To investigate this issue further, 10 normal subjects and seven ACL deficient patients were evaluated both pre- and post-operatively (mean follow-up of 6 months), and each performed multiple trials ascending a staircase which consisted of three steps. Bilateral joint angles, moments, powers, and work were measured and the data were ensemble averaged and statistically analyzed (repeated measures ANOVA with significance level set at 0.05). Anterior-posterior knee laxity decreased significantly (from 7.9 mm to 5.8 mm) while subjective knee function also improved following ACL reconstruction (knee score increased from 70.4 to 88.5). Pre-operatively, there were no statistically significant differences in biomechanical parameters between the patients' ACL-deficient and intact sides and the normal subjects. Post-operatively, however, statistically significant reductions were seen for the peak moment (91.9 vs 22.5 Nm), power (181 vs 84 W), and work performed (28.0 vs -5.6 J) at the injured knee, which was also the knee from which the patellar tendon graft had been harvested. These reductions were accommodated by significant increases in excursion, moment, and power at the contralateral ankle joint. The results indicate that while the ACL reconstruction were successful in restoring anterior-posterior knee stability, the decrease in knee power and work performed post-operatively by the injured (i.e., donor) knee suggests that donor site morbidity may need to be critically evaluated over a long-term period.

Acutely injured knee: effect of MR imaging on diagnostic and therapeutic decisions.

PURPOSE: To assess the effect of knee magnetic resonance (MR) imaging on the diagnosis and management of acute knee injury. MATERIALS AND METHODS: Two orthopedic knee surgeons prospectively completed pre- and post-MR imaging questionnaires on 84 of 91 consecutive patients with acute knee injury. The pre- and post-MR imaging clinical diagnoses, certainty regarding these diagnoses, other diagnostic tests, and subjective impression of the usefulness of MR imaging were determined. RESULTS: Seven hundred thirty-one of 840 pre- and post-MR imaging diagnoses agreed. Agreement was lowest for medial meniscal injuries (54 of 84). Significantly fewer meniscal injuries were suspected after MR imaging (P < .05). In 60 patients, the orthopedist changed at least one of the 10 potential diagnoses after MR imaging. Clinical diagnostic certainty increased by a mean of 14% for all diagnoses. The increase in diagnostic certainty was greatest for medial meniscal injuries (30%), followed by lateral meniscal injuries (21%). The proposed management changed in 41 patients, resulting in significantly fewer arthroscopic procedures (P < .01). The post-MR imaging management plans included 37% (27 of 73) fewer arthroscopic procedures. CONCLUSION: MR imaging affects the diagnosis and management of acute knee injury by decreasing the number of arthroscopic procedures, improving clinician diagnostic certainty, and assisting in management decisions.

Effect of ACL Reconstruction and Tibial Rotation on Anterior Knee Laxity.

The anterior cruciate ligament (ACL) is the primary restraint to anterior translation of the tibia on the femur. Research suggests that resistance to anterior translation changes as the tibia is rotated internally and externally. This study assessed the degree to which ACL reconstruction and tibial rotation affects anterior knee laxity. Nine subjects with ACL lesions and functional instabilities participated in the study. Subjects were measured 1 to 10 days before surgery and 6 to 8 months after ACL reconstruction using the KT-1000 knee arthrometer. A mechanical leg stabilizer was used to assess anterior translation at 20 degrees of knee flexion in three positions: internal rotation of 15 degrees , neutral, and external rotation of 15 degrees . Subjects were measured at 89 and 67 N of anterior force. Data were analyzed with a three-factor (test x position x force) repeated measures ANOVA. Following surgery, reduction in laxity (mm) for the three positions (internal rotation, neutral, and external rotation) was 1.9, 2.8, and 3.4, respectively, at 89 N and 1.5, 2.0, and 2.6, respectively, at 67 N. The degree of reduction in laxity (presurgery to postsurgery) was dependent upon rotation and force, and was greatest in external rotation and least in internal rotation pre- to postsurgery. We concluded that ACL reconstruction using a patellar tendon graft significantly decreased anterior tibial translation at all three positions, but a greater amount of reduction was observed postsurgically at the externally rotated position. This supports the theory that mechanical blocks and secondary restraints such as a taut mid-third of the iliotibial tract may interfere with clinical laxity tests in some positions of tibial rotation. Fixing the tibia in an externally rotated position may decrease the effect of secondary restraints and improve sensitivity in testing for ACL laxity.

Stress radiography of the medial elbow ligaments.

PURPOSE: To study the usefulness of stress radiography for evaluation of injury to the medial collateral ligament (MCL). MATERIALS AND METHODS: Forty-two injured athletes and four healthy athletes without symptoms underwent examination performed with a stress device. The increase in joint space width between the medial epicondyle and coronoid process, measured on anteroposterior radiographs obtained after 0 and 15 daN force was applied to the lateral elbow joint, was used to assess the extent of ligament tear. The validity of this technique was tested with study of selectively severed cadaveric MCLs. RESULTS: All complete and large partial tears were correctly diagnosed with stress radiography when the increase in joint space width was larger by 0.5 mm in the affected elbow compared with the opposite normal elbow. In subjects with values less than 0.5 mm, the MCLs were normal or showed a small tear that could be managed conservatively. CONCLUSION: Stress radiography of the MCL enables accurate diagnosis of large and complete tears and distinction between such tears and small partial tears and normal ligaments.

Instrumented arthrometry for diagnosing partial versus complete anterior cruciate ligament tears.

Nineteen patients with the clinical diagnosis of anterior cruciate ligament injury were examined by KT-1000 arthrometry before arthroscopy in an effort to differentiate partial from complete tears. To this end, the KT-1000 arthrometer was equipped with a strain gauge and processor that permitted the required force to increase the anterior displacement by 1-mm increments, to be read on a light-emitting diode. The measured force has been plotted against anterior displacement expressed in non-linear increments along the x-axis to allow for the viscoelastic nature of the ligament. The results show that stress-strain diagrams of partially torn and completely torn ligaments are similar to those obtained by graded stress radiography. Using arthroscopy as the standard of measurement, partial tears can be differentiated from complete tears with a sensitivity of 80% and a specificity of 100%. The figures for complete tears versus partial tears are 100% and 80%, respectively. Graded arthrometry with x-y recording of the force-displacement relationship that allows for the viscoelastic qualities of ligament further extends the capabilities of instrumented arthrometry.

Magnetic resonance imaging of injury to the lateral ankle ligaments.

To establish the value of magnetic resonance imaging in determining which patients with ankle sprains will benefit from surgical treatment, 1 uninjured volunteer and 15 patients with acute, subacute, and chronic injuries of the lateral ankle ligaments were imaged at 1.0 tesla using a fast imaging with steady-state precision three-dimensional technique and 1.5-mm slice thickness. A dedicated knee coil was used to hold the foot in a neutral or plantar-flexed position. In cases of acute, low-grade injuries, fraying of the anterior talofibular ligaments with intact calcaneofibular ligaments was observed in the presence of edema and hemorrhagic fluid. In cases of acute, high-grade sprains, the calcaneofibular ligament appeared wavy or was visualized only partially or not at all. Subacute injuries showed ligament disruption; chronic lesions, on occasion, showed atrophy of the calcaneofibular ligament but no edema or hemorrhagic fluid. These findings showed a good qualitative correlation with the results of graded stress radiography. Magnetic resonance imaging can definitely determine the ligaments involved in lateral ankle sprains and provide useful anatomic information in cases in which acute or reconstructive surgery is contemplated. However, the magnetic resonance imaging findings do not directly correlate with degree of instability and do not replace those of physical examination or routine radiographic studies.

Common sports hand injuries. An overview of aetiology, management and prevention.

Injuries to the hand are among the most common in all of sports. Appropriate care should include prompt diagnosis and treatment. Dislocations of the digits should be reduced promptly, particularly the carpometacarpal joint of the thumb. Volar dislocations of the proximal interphalangeal joint need to be splinted in full extension, and the more common dorsal dislocations in slight flexion. Collateral ligament injuries of the fingers respond well to initial immobilisation followed by early motion. Although ligament injuries to the thumb metacarpophalangeal joint may be treated closed, they generally respond better to operative management. This is true particularly for those occurring on the ulnar side which are at risk for soft tissue interposition. Metacarpal shaft fractures can usually be treated closed with acceptance of more significant deformity in the ulnar 2 shafts. Open reduction is reserved for multiple shaft fractures and deformity in the second and third metacarpals. Near-perfect alignment should be the goal in extra-articular fractures of the phalanges as well as fractures involving the articular surface. Closed tendon injuries occurring on the extensor side, i.e. mallet finger, may be treated with prolonged splinting if a congruous reduction can be achieved with closed reduction. Flexor side avulsions occurring most commonly in the ring finger also require prompt attention with the level of retraction of the tendon dictating the need for the immediacy of repair. Although often not initially debilitating, lack of recognition of hand injuries and improper treatment can lead to debilitating sequelae. Therefore, early recognition and diagnosis can easily avoid many of the pitfalls of care resulting in a less than optimal outcome.

Ulnar Collateral Ligament Injuries of the Thumb.

In brief Many sports, most commonly brief football and skiing, can result in injury to the ulnar collateral ligament of the thumb or its attachment sites. Abduction stress testing and radiographs can determine injury severity. Conservative measures can be used to treat incomplete ligament injuries and nondisplaced fractures; however, surgery is generally needed to repair complete ligament tears and displaced fractures. After adequate immobilization and physical therapy, patients can return to play if the ligament is protected with splinting or taping.

Compressive neuropathies in the upper extremity of athletes.

The physician responsible for the evaluation and treatment of athletes must include nerve compression injury in the differential diagnosis of upper extremity pain and dysfunction. Careful history and physical examination, along with selective objective testing, should be diagnostic. Treatment and prevention methods implemented under the supervision of knowledgeable trainers and coaches may allow for complete resolution of symptoms and, more importantly, prevent recurrence. Adolescents and novice athletes in many sports may be at the highest risk for this type of overuse injury.

Relationship between Selected Physical Characteristics and Functional Capacity in the Anterior Cruciate Ligament-Insufficient Athlete.

Traditionally, clinicians have utilized various physical characteristics as criteria to assess the functional status of anterior cruciate ligament (ACL)-insufficient athletes without validating the efficacy of such assessments. The primary purposes of this study were to determine the relationship between traditionally used physical characteristics and functional capacity of individuals with an ACL insufficiency and to compare functional results of two groups of ACL-insufficient athletes. Forty-one subjects were tested for strength and power on an isokinetic device, anthropometric characteristics, and function using three functional performance tests (FPT). Results revealed that conventional physical characteristics correlated poorly (r = .01 to r = .42) with the functional tests. Additionally, athletes who were able to return to preinjury levels of activity performed significantly (p < 0.05) better on the FPT than those who were unable to return to preinjury activities. Based on the results of this study, use of such traditional physical characteristics for predicting function in the ACL-insufficient athlete may be inappropriate, and the functional performance tests designed for this study appear to be the most valuable assessment of the athlete's functional capacity. J Orthop Sports Phys Ther 1992;16(4):174-181.

Metacarpophalangeal and proximal interphalangeal joint injuries of the hand, including the thumb.

There is no cookbook approach to the treatment of a swollen finger or thumb. Different injury patterns may require different types of immobilization and different periods of abstinence from participation. Certain articular fractures and collateral ligament injuries have better results when treated with primary surgical intervention. It is only through accurate evaluation and adequate treatment that we may prevent long-term disability secondary to articular injuries of the fingers and thumb.

Graded stress radiography of injured anterior cruciate ligaments.

Fifty-five patients with clinical suspicion of injury to their anterior cruciate ligament (ACL) were examined by graded stress radiography before arthroscopic verification in an effort to determine the loss of ACL function as a result of ligament tearing. Using a commercially available stress device capable of applying varying pressures to the mid-calf, anterior drawers were measured from lateral radiographs at 0-, 7-, 14-, and 21-kiloPascal pressures and used to calculate the equivalent elastic modulus of the remaining ACL fibers. According to viscoelastic theory, this modulus is proportional to the number of elastically active fibers in the ligament. To verify the validity of this concept, the stress-strain relationship of a freshly excised ACL ligament was examined in a tensile testing machine, and the procedure was repeated after the ligament had been partially transsected with a scalpel. Comparison with the elastic modulus of the (intact) ACL of the opposite knee permits an estimate of the percentage of rupture in cases of partial tears. Overstretched ligaments show essentially normal viscoelastic properties once the slack in the ligament has been taken up. Complete tears, on the other hand, show a complete breakdown in the viscoelastic properties of the ACL. The results show that partial tears can be diagnosed by graded stress radiography with a sensitivity of 20% and specificity of 90%. Diagnosis of overstretched ligaments had sensitivity of 50% and specificity of 94%. Complete tears were detected with sensitivity of 88% and specificity of 75% as diagnosed against all other ACL lesions and including normals.(ABSTRACT TRUNCATED AT 250 WORDS)

Rehabilitation of common athletic injuries of the hand and wrist.

Rehabilitation of athletic injuries of the hand and wrist should begin at the time of injury. Early recognition and prompt medical attention can serve to minimize the initial effects of injury. A systematic evaluation should include assessment of deformity, joint instability, active and passive motion, edema, and nerve and tendon function. In spite of initial negative findings, painful joints should be protected. Joints of the hand and wrist are particularly vulnerable to the effects of aggressive rehabilitation. Signs of reaction to exercises should be closely observed. Upgrading of activity should only occur as soft-tissue healing will allow.