Refracture of proximal fifth metatarsal (Jones) fracture after intramedullary screw fixation in athletes.

This study details six instances of refracture of clinically and radiographically healed fractures of the base of the fifth metatarsal after intramedullary screw fixation. Four professional football players, one college basketball player, and one recreational athlete underwent intramedullary screw fixation of fifth metatarsal fractures. The athletes were released to full activities an average of 8.5 weeks (range, 5.5 to 12) after fixation, when healing was clinically and radiographically documented. Three football players developed refracture within 1 day of return to full activity. The other three athletes refractured at 2.5, 4, and 4.5 months after return to activity. Two football players underwent repeat fixation with larger screws and returned to play in the same season. The college basketball player underwent bone grafting and returned to play in subsequent seasons. The other three athletes underwent nonoperative management and healed uneventfully over 6 to 8 weeks. On the basis of this series, we recommend that 1) screw fixation using a large-diameter screw should be given careful consideration for patients with large body mass for whom early return to activity is important; 2) functional bracing, shoe modification, or an orthosis should be considered for return to play; 3) if refracture occurs, exchange to a larger screw may allow return to play in the same season; and 4) alternative imaging should be considered to help document complete healing.

Stiffness, viscosity, and upper-limb inertia about the glenohumeral abduction axis.

To evaluate the dynamic properties of the shoulder and understand how they are controlled by the central nervous system, glenohumeral-joint stiffness and viscosity and upper-limb inertia were quantified under various levels of muscle contraction in seven healthy human subjects. Through a cast attachment, the upper limb was perturbed in a precise pattern by a computer-controlled servomotor to manifest the dynamic properties of the joint. The recorded joint position and torque were used to estimate joint stiffness and viscosity and upper-limb inertia. With moderate muscle contraction, the stiffness and viscosity increased several fold. A stiffer shoulder joint associated with stronger muscle contraction made the shoulder more stable and protected it from potential injuries during strenuous tasks. Joint viscosity, especially the stronger viscous damping associated with more strenuous contraction, smoothed shoulder movement and stabilized the joint. From the control viewpoint, the glenohumeral joint responded to the central nervous system more quickly with increasing muscle contraction, which was useful during strenuous tasks. On the other hand, the central nervous system controlled stiffness and viscosity synchronously so that it dealt with only a nearly constant damping ratio of the joint over various levels of contraction, which simplified its task substantially. This approach quantified the dynamic and static properties of the shoulder under various levels of contraction more accurately and completely than a manual test, and it can potentially be used to evaluate changes in these properties caused by musculoskeletal injuries and their surgical treatments.

Moment distribution among human elbow extensor muscles during isometric and submaximal extension.

To understand better how the central nervous system (CNS) distributes a joint moment among muscles, moment distribution among the three heads of the triceps and the anconeus muscles during isometric elbow extension was quantified in vivo and noninvasively. Electrical stimulation was used to activate an individual muscle selectively at various contraction levels, and the relationship between the peak M-wave amplitude and peak elbow extension moment was established across various contraction levels for each muscle. The relationship was then used to calibrate the corresponding EMG signal and determine moment distribution among the muscles during voluntary isometric elbow extension. Results showed that moment distribution among muscles was not proportional to the muscles' physiological cross-sectional areas (PCSA) and the CNS favored uniarticular muscles for the isometric task performed: the uniarticular lateral and medial heads of the triceps were dominant (contributing approximately 70-90% of the total elbow extension moment) and the anconeus contributed significantly, especially at the lower levels of elbow extension moment (up to approximately 15% of the extension moment). In contrast, the two-joint long head of the triceps contributed significantly less than the uniarticular heads of the triceps. While the absolute contributions of all the muscles increased with the total elbow extension moment, the relative contributions of the muscles may increase or decrease with the elbow extension moment. Cross-validation using fresh data (not used in determining the moment distribution) showed close match between the measured and predicted elbow extension moment except for trials in which fatigue became significant.

Radiographic evaluation of the position of implants in the medial malleolus in relation to the ankle joint space: anteroposterior compared with mortise radiographs.

BACKGROUND: Displaced transverse fractures of the medial malleolus are commonly treated with open reduction and internal fixation with two screws or wires. A mortise radiograph is often used to verify the position of the implants relative to the joint space. However, because the medial and lateral talomalleolar spaces are normally not parallel, the mortise projection (which is colinear with the lateral space) does not provide an accurate radiograph of the medial joint space. METHODS: In ten cadaveric ankles, two wires were inserted into the medial malleolus, as is done for fixation of a fracture, and the distance of the wires from the joint space was measured on an anteroposterior radiograph, on mortise radiographs made with the foot in 15 and 30 degrees of internal rotation, and on anatomical cross section. RESULTS: The measurement on the anteroposterior radiograph exceeded the anatomical measurement in only two specimens, and the discrepancy was 0.5 millimeter in both instances. Measurement of the osseous thickness between the joint surface and the posterior wire on the mortise radiographs always revealed a lower value than the measurements on the anteroposterior radiograph and the anatomical cross section of the same specimen. There was a false appearance of intra-articular placement of the posterior wire on the 15-degree mortise radiographs of four specimens and on the 30-degree mortise radiographs of eight specimens. CONCLUSIONS: These findings demonstrate that the mortise projection provides an oblique radiograph of the medial joint space that can inaccurately reflect the true position of fixation implants in the medial malleolus. Because an anteroposterior radiograph is made with the articular surface of the medial malleolus tangential to the beam, it provides a more accurate representation of implants in the medial malleolus.

Engineering bone regeneration with bioabsorbable scaffolds with novel microarchitecture.

Critical-sized defects (CSDs) were introduced into rat calvaria to test the hypothesis that absorption of surrounding blood, marrow, and fluid from the osseous wound into a bioabsorbable polymer matrix with unique microarchitecture can induce bone formation via hematoma stabilization. Scaffolds with 90% porosity, specific surface areas of approximately 10 m2/g, and median pore sizes of 16 and 32 microm, respectively, were fabricated using an emulsion freeze-drying process. Contact radiography and radiomorphometry revealed the size of the initial defects (50 mm2) were reduced to 27 +/- 11 mm2 and 34 +/- 17 mm2 for CSDs treated with poly(D,L-lactide-co-glycolide). Histology and histomorphometry revealed scaffolds filled with significantly more de novo bone than negative controls (p < 0. 007), more osteoid than both the negative and autograft controls (p < 0.002), and small masses of mineralized tissue (< 15 mm in diameter) observed within the scaffolds. Based on these findings, we propose a change in the current paradigm regarding the microarchitecture of scaffolds for in vivo bone regeneration to include mechanisms based on hematoma stabilization.

Anatomy and histological characteristics of the spinoglenoid ligament.

The spinoglenoid (inferior transverse scapular) ligament, when present, is located at the spinoglenoid notch. The ligament originates on the spine of the scapula and inserts on the superior margin of the glenoid neck. Because of discrepancies in the literature, we sought to determine its prevalence and to define its histological characteristics. We dissected 112 shoulders of seventy-six cadavera and classified the ligament as absent or an insubstantial structure, a thin fibrous band (type I), or a distinct ligament (type II). We found no distinct ligamentous structure in twenty-two shoulders (20 percent), a type-I ligament in sixty-eight shoulders (61 percent), and a type-II ligament in twenty-two shoulders (20 percent). Overall, ninety (80 percent) of the shoulders had a fibrous band of tissue that, together with the spine of the scapula, formed a narrow fibro-osseous tunnel through which the suprascapular nerve traveled. The bone-spinoglenoid ligament-bone complexes from three specimens were analyzed histologically. There were two type-I ligaments and one type-II ligament; all three ligaments were composed of collagen fibers. One type-I ligament and the type-II ligament demonstrated Sharpey fibers at their origin on the spine of the scapula. The other type-I ligament attached to the spine of the scapula through the periosteum. All three ligaments inserted into the periosteum of the glenoid neck.

Neurovascular problems in the forearm, wrist, and hand.

This article attempted to summarize the most common neurovascular injuries of the upper extremity, particularly the forearm, wrist, and hand. Although these injuries are rarely encountered in athletes, their pathology and treatment must be understood by the treating physician. Failure to recognize these injuries in a timely manner can lead to delay in diagnosis and weeks or months of lost participation by the athlete. The sports medicine physician must be aware of the potential risk for injury to the neurovascular structures, particularly in the athlete exposed to repetitive use or impact of the upper extremity. Timely recognition, diagnosis, and treatment will avoid the potential risk for permanent injury.

In vivo human knee joint dynamic properties as functions of muscle contraction and joint position.

Information on the dynamic properties (joint stiffness, viscosity and limb inertia) of the human knee joint is scarce in the literature, especially for actively contracting knee musculature. A joint driving device was developed to apply small-amplitude random perturbations to the human knee at several flexion angles with the subject maintaining various levels of muscle contraction. It was found that joint stiffness and viscosity increased with muscle contraction substantially, while limb inertia was constant. Stiffness produced by the quadriceps was highest at 30 degrees flexion and decreased with increasing or decreasing flexion angle, while knee flexors produced highest stiffness at 90 degree flexion. When knee flexion was < 60 degrees, stiffness produced by the quadriceps was higher than that of the hamstrings and gastrocnemius at the same level of background muscle torque, while knee flexor muscles produced higher stiffnesses than the quadriceps at 90 degree flexion. Similar but less obvious trends were observed for joint viscosity. Passive joint stiffness at full knee extension was significantly higher than in more flexed positions. Surprisingly, as the knee joint musculature changed from relaxed to contracting at 50% MVC, system damping ratio remained at about 0.2. This outcome potentially simplifies neuromuscular control of the knee joint. In contrast, the natural undamped frequency increased more than twofold, potentially making the knee joint respond more quickly to the central nervous system commands. The approach described here provides us with a potentially valuable tool to quantify in vivo dynamic properties of normal and pathological human knee joints.

In vivo determination of the direction of rotation and moment-angle relationship of individual elbow muscles.

The direction of rotation (DOR) of individual elbow muscles, defined as the direction in which a muscle rotates the forearm relative to the upper arm in three-dimensional space, was studied in vivo as a function of elbow flexion and forearm rotation. Electrical stimulation was used to activate an individual muscle selectively, and the resultant flexion-extension, supination-pronation, and varus-valgus moments were used to determine the DOR. Furthermore, multi-axis moment-angle relationships of individual muscles were determined by stimulating the muscle at a constant submaximal level across different joint positions, which was assumed to result in a constant level of muscle activation. The muscles generate significant moments about axes other than flexion-extension, which is potentially important for actively controlling joint movement and maintaining stability about all axes. Both the muscle DOR and the multi axis moments vary with the joint position systematically. Variations of the DOR and moment-angle relationship across muscle twitches of different amplitudes in a subject were small, while there were considerable variations between subjects.

Patellar taping in the treatment of patellofemoral pain. A prospective randomized study.

The purpose of this prospective study was to evaluate the efficacy of a patellar taping program in the conservative management of patellofemoral pain. Twenty-five patients with patellofemoral pain were randomized into two groups. One group underwent a standard physical therapy program for patellofemoral pain. The other group underwent the same physical therapy program, but use of a patellar taping technique was added to this program. Results of a subjective visual analog scale and changes in isokinetic strength and electromyographic activity of the quadriceps muscle were analyzed. Both the tape and no-tape groups experienced a statistically significant decrease in symptoms (P < 0.05), but no difference in improvement of patellofemoral pain was noted between the groups. Likewise, both groups demonstrated significant improvement in quadriceps muscle isokinetic strength (P < 0.05) and activity (P < 0.001), but no difference in improvement was noted between groups. The results of this study suggest no beneficial effect of adding a patellar taping program to a standard physical therapy program in the conservative treatment of patellofemoral pain. Larger prospective studies are warranted to support this opinion.

Arterial injuries in the thoracic outlet syndrome.

PURPOSE: This article reviews experience with arterial injury caused by thoracic outlet syndrome. Special emphasis is placed on the influence of athletic or work activities on the axillary-subclavian artery system and the mechanism by which the humeral head compresses the axillary artery and the circumflex humeral arterial branches. METHODS: Retrospective review identified 34 patients (age range 13 to 67 years) treated for upper extremity symptoms or ischemic complications of thoracic outlet syndrome from 1983 to 1993. Evaluation included assessment of occupational and recreational activities plus duplex ultrasonography and contrast arteriography with positional maneuvers. RESULTS: Twenty-two patients (27 arms) had subclavian artery injury, which was most commonly caused by compression by a bony abnormality (cervical rib, 16; anomalous first rib, two; cervical rib and anomalous first rib, two). Fourteen of the 27 arms had distal embolization. All 27 had surgical decompression of the subclavian artery; 15 required concomitant arterial reconstruction. Twelve additional patients (nine athletes) had axillary artery involvement, all from arterial compression by the head of the humerus during abduction maneuvers; all had concomitant compression of the posterior circumflex humeral artery. Axillary arterial injury included thrombosis (one), aneurysm (two), and symptomatic extrinsic compression only (nine). Five patients with axillary artery involvement were treated without a surgical procedure; of the remainder, three underwent decompression procedures only, and four had direct arterial repair. In both groups all subclavian and axillary artery reconstructions were patent at last follow-up examination (mean 31 months). CONCLUSION: Most patients with thoracic outlet syndrome who have arterial involvement have a bony anomaly causing subclavian artery compression. This study demonstrates that humeral head compression of the axillary artery and its circumflex branches is a surprisingly common pathologic mechanism. Awareness of this condition affords a better therapeutic approach to arterial injuries caused by thoracic outlet syndrome.

Olecranon stress fractures in throwers. A report of two cases and a review of the literature.

The evaluation and treatment of elbow injuries in throwing athletics has been the topic of numerous articles. The intense and repetitive stresses placed on the elbow may, in rare instances, produce undisplaced olecranon stress fractures. Two cases are presented and the literature is reviewed to propose that the fractures can be successfully treated by conservative methods.

Cost offset from a psychiatric consultation-liaison intervention with elderly hip fracture patients.

OBJECTIVE: The authors hypothesized that psychiatric liaison screening of elderly patients with hip fractures would shorten the average length of hospital stay and increase the proportion of patients who returned home after discharge. METHOD: The study was performed at Mount Sinai Medical Center in New York and Northwestern Memorial Hospital in Chicago. The subjects were 452 patients 65 years or older who were consecutively admitted for surgical repair of fractured hips. During a baseline year the patients received traditional referral for psychiatric consultation. During the experimental year all the patients at Mount Sinai and the patients on one Northwestern Unit were screened for psychiatric consultation. RESULTS: The patients who received psychiatric liaison screening had a higher consultation rate than those who received traditional consultation. The rates of DSM-III disorders in the experimental year were 56% at Mount Sinai and 60% at Northwestern. The mean length of stay was reduced from 20.7 to 18.5 days at Mount Sinai and from 15.5 to 13.8 days at Northwestern, resulting in reductions in hospital costs ($647/day) of $166,926 and $97,361, respectively. Fees generated from Medicare service delivery could have paid for the $20,000 psychiatric intervention cost at each site. There was no difference, however, between the two years in the discharge placement of patients. CONCLUSIONS: Admission psychiatric liaison screening of elderly patients with hip fractures results in early detection of psychiatric morbidity, better psychiatric care, earlier discharge, and substantial cost savings to the hospital.

The contribution of the glenohumeral ligaments to anterior stability of the shoulder joint.

The purpose of this study was to investigate the ligamentous stabilizing mechanisms preventing anterior instability in the glenohumeral joint. Six freshly thawed, unembalmed cadaveric shoulders were dissected, preserving the joint capsule and glenohumeral ligaments, the coracohumeral ligament, and the subscapularis tendon. Hall-effect strain transducers were placed on the superior, middle, and inferior glenohumeral ligaments. The humerus and scapula were fixed in a specifically designed mounting apparatus that allowed the glenohumeral joint to be placed in 0 degree, 45 degrees, or 90 degrees of abduction. The mounting apparatus was placed in a model TTC Instron Universal Testing Instrument, which applied an external rotation torque to the humerus. Strain produced in the three glenohumeral ligaments was recorded on a three-channel X-Y chart recorder. At 0 degree of abduction, the superior and middle glenohumeral ligaments developed the most strain. At 45 degrees of abduction, the inferior and middle glenohumeral ligaments developed the most strain, with considerable strain also being developed in the superior glenohumeral ligament. At 90 degrees of abduction, the inferior glenohumeral ligament developed the most strain, with strain also seen in the middle glenohumeral ligament.

Arterial abnormalities of the shoulder in athletes.

Vascular lesions of the shoulder may be misinterpreted as one of the more familiar shoulder abnormalities by a treating physician. We are reporting on 13 athletes who were found to have symptoms related to compression of the subclavian or axillary artery or their tributaries. Nine were amateur or professional baseball pitchers. Severe arm fatigue or finger ischemia, secondary to embolization, were presenting symptoms. Arm fatigue was noted in all pitchers. After complete history and physical examination, including auscultation for bruits in functional positions, all athletes were evaluated by noninvasive tests (Doppler and Duplex scanning). Arteriography was performed with positional testing, recreating overhead activity, and complete radiographic visualization of the dye to the digital arteries. Two patients were found to have subclavian artery aneurysm. The remaining athletes were found to have compression of the subclavian artery beneath the anterior scalene muscle (five patients), the axillary artery beneath the pectoralis minor (two patients), both arterial segments (two patients), and one was found to have arterial compromise at the level of the humeral head. Branch artery compression was also noted. One pitcher occluded the posterior circumflex humeral artery with embolization to the digit. The two patients with subclavian aneurysms underwent saphenous vein bypass with cervical rib resection. All of the other athletes except one underwent resection of a 2 to 3 cm segment of the anterior scalene muscle or pectoralis minor muscles. All returned to their previous level of activity except one patient who developed impingement type symptoms and required acromioplasty. He is currently undergoing rehabilitation. Proper recognition of vascular compromise in the upper extremity of athletes is essential to avoid the catastropic complications of arterial thrombosis.

Arterial abnormalities of the hand in athletes.

Vascular lesions of the hand may be seen in athletes exposed to repetitive blunt trauma. Thirteen athletes seen from 1983 to 1988 experienced symptoms related to hand ischemia. Nine were professional baseball catchers. The majority of patients complained of chronic symptoms, including cold hypersensitivity (four patients), finger numbness (one), finger coolness (three), and finger blanching (three). Two patients had acute symptoms with sudden posttraumatic hand ischemia with finger and palmar pain. Diagnosis was established by history and physical examination and confirmed by noninvasive testing. Testing included use of Doppler examination and cold tolerance examination with thermistors. Two athletes required angiographic evaluation because of severe ischemia and continuous pain. All patients in this group were managed nonoperatively. Those with chronic complaints were counseled regarding cold avoidance and instructed to increase their glove padding. The two patients with acute symptoms required vasodilator (papaverine chloride) infusion, followed by intravenous heparin and dextran. All baseball catchers returned to their sport with dissipation of symptoms.

Biomechanics of the foot and ankle during gait.

Running is a very popular activity, whether for competition or fitness. Breakdown injuries related to training errors, shoe wear, or change in intensity are frequently seen by the sports medicine physician. In order to understand and treat the pathologic situation, a fundamental understanding of the biomechanics of walking and running is essential. The treating practitioner must appreciate the distinct differences between the walking and running gait. These differences transcend a simple increase in speed of gait and include distinct changes in joint range of motion and electromyographic activity. Armed with this knowledge, the practitioner treating a breakdown injury can work to a solution based on scientific understanding rather than anecdotal information.