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Biomedical subjects

R F Warren

Publications and source records attributed to R F Warren.

At least 235 records · Page 13Linked to original sources
PubMedDate not supplied

Rotator cuff injury in contact athletes.

The causes and incidence of rotator cuff injuries in patients under the age of 40 has not been clearly established. The present study focuses on a group of 10 male contact athletes with rotator cuff injuries related to trauma sustained during football (ages from 24 to 36 years). Symptoms included pain and dysfunction in all 10 patients and a positive shrug sign in 8 of 10. The diagnoses for these patients were two isolated contusions, five partial-thickness tears, and three full-thickness tears. Surgery was performed on all patients after nonoperative treatment failed. Three partial-thickness tears were arthroscopically debrided. One full-thickness and two partial-thickness tears were repaired using the arthroscopically assisted miniarthrotomy technique. An open repair was performed in two patients. Two isolated rotator cuff contusions were arthroscopically debrided. The average followup was 21 months. Nine of 10 athletes returned to active participation in football, 7 of these at their preinjury levels. The diagnosis of rotator cuff injury should be considered in a contact athlete who has persistent shoulder pain, impingement signs, weakness, and a positive shrug sign. Arthroscopic debridement of the subacromial space followed by debridement or repair of rotator cuff tears, as clinically indicated, resulted in a marked improvement in function and rapid return to sport for these patients.

Acromion↗
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The popliteofibular ligament. Rediscovery of a key element in posterolateral stability.

We have recently become aware of a strong direct attachment of the popliteal tendon to the fibula. To investigate the importance of this attachment, we examined 20 cadaveric knees. The popliteofibular ligament was identified in all 20 knees. The cross-sectional area of the popliteofibular ligament was 6.9 +/- 2.1 mm2, compared with 7.2 +/- 2.7 mm2 for the lateral collateral ligament. Biomechanical testing of these structures, simulating a purely varus stress on the knee, revealed that the lateral collateral ligament always failed first, followed by the popliteofibular ligament, and then the muscle belly of the popliteus. The mean maximal force to failure of the popliteofibular ligament approached 425 N (range, 204 to 778), compared with 750 N (range, 317 to 1203) for the lateral collateral ligament. Our results indicate that the popliteofibular ligament contributes to posterolateral stability.

Adult↗
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Arthroscopic shoulder stabilization using transglenoid sutures. A four-year minimum followup.

Thirty-seven of 41 consecutive patients with recurrent anterior instability of the shoulder were retrospectively observed for a mean of 5.6 years (range, 4 to 10) after an arthroscopic stabilization procedure had been performed. The operative technique involved the use of transglenoid sutures to repair the capsule and labrum. According to the criteria established by Rowe, 27 patients (74%) had good or excellent results, and 3 patients (7%) were graded as fair. Seven patients (19%) developed recurrent instability after the procedure and had failed results. Failure rates were equal in patients with a history of recurrent dislocation and those with recurrent subluxation. Absence of a Bankart lesion at operation was associated with postoperative instability (P = 0.03). The presence or size of humeral head defects did not influence the result. Eight of 12 athletes who engaged in sports requiring repetitive overhead shoulder motion returned to full activity, and none of the 12 developed instability after operation. Four of the 13 patients who participated in contact sports or recreational skiing developed postoperative instability (P = 0.21). All failures occurred within 2 years of the procedure.

Adolescent↗
PubMedDate not supplied

Traumatic tears of the subscapularis tendon. Clinical diagnosis, magnetic resonance imaging findings, and operative treatment.

The study population consisted of 14 shoulders in 13 consecutive patients with surgically confirmed isolated subscapularis tendon tears. In all but three patients, the mechanism of injury was traumatic hyperextension or external rotation of the abducted arm. All patients reported pain and weakness in the affected shoulder. Physical findings revealed limited passive range of motion at maximal internal and external rotation due to pain, weakness of internal rotation of the shoulder, and tenderness in the region of the intertubercular groove. However, these findings did not conclusively point to the subscapularis tendon as the site of injury. Preoperative interpretation of magnetic resonance imaging studies was used to diagnose tears of the subscapularis tendon in 14 shoulders and biceps tendon subluxation or dislocation in 6 shoulders. On arthroscopic examination, one patient was found to have a partial-thickness tear that was treated with arthroscopic debridement. Six shoulders had full-thickness tears of the subscapularis tendon, and seven shoulders had full-thickness tears associated with concomitant biceps tendon pathologic conditions, including subluxation, dislocation, or rupture. The full-thickness subscapularis tendon tears were repaired via an open anterior approach to the shoulder through the deltopectoral groove. Associated biceps tendon injuries were treated with tenodesis of the tendon to the intertubercular groove. Our early followup results have shown that, with proper diagnoses and surgical treatments, patients have greatly decreased pain and marked improvement in shoulder function.

Adolescent↗
PubMedDate not supplied

Septic arthritis after arthroscopic anterior cruciate ligament reconstruction. Diagnosis and management.

We performed a retrospective study of knee joint infections after arthroscopic anterior cruciate ligament reconstruction at our institution. Two thousand five hundred anterior cruciate ligament reconstructions were performed between 1988 and 1993. Seven (0.3%) patients experienced postoperative deep infections of the knee. All anterior cruciate ligament reconstructions were performed using arthroscopically assisted techniques. Six (86%) of these patients had concomitant open procedures performed, including meniscal repair, posterolateral corner reconstruction, and medial collateral ligament reconstruction. Four patients had acute (< 2 weeks), two patients had subacute (2 weeks to 2 months), and one patient had late (> 2 months) infections. All patients had positive cultures from knee joint aspirates with the organisms Staphylococcus aureus, Staphylococcus epidermidis, Peptostreptococcus, or a combination thereof. All patients underwent immediate arthroscopic irrigation and debridement. All infections were intraarticular; six patients also had extraarticular sites of infection. Four patients underwent repeat irrigation and debridement at approximately 1 week. The anterior cruciate ligament graft was removed from four patients. All patients were treated with intravenous antibiotics for 4 to 6 weeks, protected weightbearing, and physical therapy. At a mean followup of 29 months, mean knee extension was 0 degree, and mean knee flexion was 122 degrees (range, 70 degrees to 135 degrees). Six (86%) patients had minimal to no pain in their operative knee, and they were satisfied with their functional results.

Adolescent↗
PubMedDate not supplied

Arthroscopic treatment of partial rotator cuff tears in young athletes. A preliminary report.

Forty-three athletes under age 40, more than half of which were collegiate or professional, with partial rotator cuff tears were treated arthroscopically and observed for a minimum of 24 months. By history and mechanism of injury, two main groups were identified. Group A had 14 patients with acute, traumatic injuries. All 14 had inflamed subacromial bursas, but increased glenohumeral translation and labral lesions were uncommon. Twelve patients (86%) had satisfactory postoperative results and nine (64%) returned to preinjury sports after arthroscopic subacromial decompression and tear debridement. Group B had 29 overhead athletes with insidious, atraumatic shoulder pain. They were not as successful with debridement (19 [66%] satisfactory and 13 [45%] return to preinjury sports). Within Group B, three subgroups were identified based on the examination under anesthesia and subacromial inflammation. Group B1 (8 patients) had normal-appearing subacromial spaces and often increased anterior glenohumeral translation with posterior labral tears. These patients did poorly after arthroscopic tear debridement (3 [38%] satisfactory and 2 [25%] return to sports). Group B2 (12 patients) had inflamed subacromial bursas and increased glenohumeral translation. This group had marginal results with debridement (7 [58%] satisfactory and 6 [50%] return to sports). Group B3 (9 patients) with subacromial inflammation, yet without increased glenohumeral translation, had excellent pain relief (100%) but less than half (4) returned to preinjury sports.

Adult↗
PubMedDate not supplied

The combined dynamic and static contributions to subacromial impingement. A biomechanical analysis.

Ten human cadaveric shoulders were tested with a dynamic shoulder model simulating physiologic rotator cuff, deltoid, and biceps muscle forces. The combined effect of the muscle forces and acromial structure on subacromial impingement was measured with minimally invasive, miniature pressure transducers. Shoulders with large acromial spurs had significantly greater impingement pressures at the anterolateral acromion in neutral, internal, and external rotation compared with those with flatter acromia. Application of a biceps muscle force reduced anterolateral acromial pressures by 10%. Failure to simulate a supraspinatus force decreased acromial pressure 52% in shoulders with type III acromia in neutral rotation. Without rotator cuff forces applied, the maximum deltoid muscle force required to elevate the arm increased by 17%. Acromial pressures were increased when no rotator cuff forces were applied, but the increases were not significant. After an anterior acromioplasty, pressures decreased by 99% anteriorly. However, failure to achieve a flat surface posteriorly increased pressures in this location, especially with the shoulder in external rotation. Modeling the rotator cuff and deltoid muscle forces demonstrated the importance of the muscular force couple to center the humeral head during elevation of the arm. The inferior forces of the infraspinatus, teres minor, and subscapularis muscles were necessary to neutralize the superior shear force produced by the deltoid and supraspinatus muscles.

Acromioclavicular Joint↗
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Popliteomeniscal fasciculi and lateral meniscal stability.

In an attempt to understand better the contribution of the anteroinferior and posterosuperior popliteomeniscal fasciculi to lateral meniscus stability, we objectively evaluated the stability of the lateral meniscus before and after sequentially sectioning these fasciculi. In the biomechanical model, we attempted to account for the inherent limitations of arthroscopic evaluation of lateral meniscal stability. When the fasciculi were intact, the average lateral meniscal motion with a 10-N load was 3.6 mm. When the anteroinferior fascicle was disrupted, the average lateral meniscal motion with a 10-N load was 5.4 mm. The mean increase in motion from the intact state was 1.8 mm or 50%, which was significant. When both fasciculi were disrupted, the average lateral meniscal motion with 10-N load was 6.4 mm. The mean increase in motion from the intact state was 2.8 mm or 78% and from the single fascicle disruption state was 1.0 mm or 18%, both differences were significant. The meniscus did not become locked with any of these loading trials, and it spontaneously reduced to the original position when unloaded. Both fasciculi make significant contributions to meniscal stability. Even though the meniscus never became locked in the joint when loaded during this study, with the variable loads seen with normal activities mechanical symptoms might be expected when meniscal motion is almost double. An increase in lateral meniscal motion at the time of surgery may aid in the diagnosis of fasciculi disruption, despite normal meniscal structure on magnetic resonance images and at arthroscopic visualization.

Aged↗
PubMedDate not supplied

Contact pressures at osteochondral donor sites in the knee.

The purposes of this study were to determine whether any of the commonly recommended osteochondral donor sites are nonarticulating throughout a functional range of knee motion, and to determine the differential contact pressures for these sites. Ten commonly recommended sites for osteochondral harvest were evaluated with pressure-sensitive film through a functional range of motion with a model that simulated nonweightbearing resistive extension of the knee. All 10 donor sites demonstrated a significant contact pressure through 0 degree to 110 degrees of knee motion. The different color density measurements between donor sites were also significant. Although donor sites 1, 2, 9, and 10 demonstrated significantly less contact pressure than the sites with the greatest contact pressure, the difference in mean pressures was small. No osteochondral donor site tested was free from contact pressure. It is currently unknown whether articular contact at these osteochondral donor sites will lead to degenerative changes or any other problems.

Aged↗
PubMedDate not supplied

Analysis of collagen and elastic fibers in shoulder capsule in patients with shoulder instability.

This study examined collagen cross-links, collagen fibril diameter and density, amino acid composition, and elastic fibers in shoulder capsule and skin in four patient groups: 1) unidirectional anterior instability (N = 8); 2) multidirectional instability/primary surgery (N = 6); 3) multidirectional instability/revision surgery (N = 6); and 4) no history of instability (N = 5). Compared with normal capsule, capsule from groups 1 and 2 had more stable and reducible collagen cross-links, significantly greater mean collagen fibril diameter, more cysteine, and a higher density of elastin staining. Compared with shoulder capsule in groups 1 and 2, shoulder capsule from group 3 contained significantly more reducible cross-links, smaller-diameter collagen fibrils, decreased collagen fibril density, and an increased density of elastin staining. There were no significant differences in any parameters between groups 1 and 2. We hypothesized that repeated capsular deformation in patients with shoulder instability results in changes in the capsule that increase its strength and resistance to stretching. Skin analyses demonstrated a significantly smaller mean collagen fibril diameter in skin from group 2 compared with group 1, suggesting the possibility of an underlying connective tissue abnormality.

Adolescent↗
PubMedDate not supplied

Postexercise increase in nitric oxide in football players with muscle cramps.

Nitric oxide, a free radical inter- and intracellular messenger molecule, is important in exercise physiology. This study tested the hypothesis that serum nitric oxide concentrations change after strenuous exercise with severe generalized muscle cramps. The study group consisted of 77 professional football players in preseason training. All players' concentrations of serum nitrite and of other serum chemicals were determined during their preseason evaluations and compared with the concentrations in 40 serum samples taken from 25 of those same players who required intravenous rehydration for severe generalized muscle cramps after a training session. Player weight and percentage of body fat were significantly higher in players who received intravenous fluids than in players who did not. The serum of players requiring intravenous hydration showed evidence of skeletal muscle breakdown (increases in lactate dehydrogenase, creatinine phosphokinase, aspartate aminotransferase, and alanine aminotransferase) and of dehydration (elevations in protein, blood urea nitrogen, and cholesterol). The major finding, however, was a nearly 300% increase in serum nitrite concentrations in players requiring rehydration. There were no correlations between concentrations of nitrate and of any of the other serum chemicals. These data support the hypothesis that large amounts of nitric oxide are synthesized in professional football players after strenuous exercise with severe muscle cramps. The study design did not allow us to determine whether this increase in nitric oxide was due to exercise or muscle cramps or both, but it does provide a basis for evaluating these relationships.

Adult↗
PubMedDate not supplied

Noncontrast magnetic resonance imaging of superior labral lesions. 102 cases confirmed at arthroscopic surgery.

Previous studies report that noncontrast magnetic resonance imaging is limited in the evaluation of the superior glenoid labrum. From our magnetic resonance imaging database of 2552 patients, we prospectively identified 104 patients with superior labral lesions who subsequently went on to arthroscopic surgery. Magnetic resonance images were assessed to identify fraying, flap tears, bucket-handle tears, or displaced flap of fibrocartilage. The biceps tendon was also evaluated. Patients were categorized according to Snyder's classification, and the findings on the magnetic resonance images were correlated with surgical findings. One hundred of the 104 tears suspected on the images were confirmed at surgery. There were four false-positives and two false-negatives, the former reflecting one normal labrum, two meniscoid-type labra, and one sublabral foramen. With arthroscopic surgery as the standard, magnetic resonance imaging had a sensitivity of 98.0% (100 of 102), a specificity of 89.5% (34 of 38), and an accuracy of 95.7% (134 of 140) for detection of superior labral lesions. We concluded that high-resolution noncontrast magnetic resonance imaging can accurately diagnose superior labral lesions and aid in surgical management.

Adolescent↗
PubMedDate not supplied

Use of recombinant human bone morphogenetic protein-2 to enhance tendon healing in a bone tunnel.

This study examines the hypothesis that recombinant human bone morphogenetic protein-2 can enhance bone ingrowth into a tendon graft placed into a bone tunnel. We transplanted the long digital extensor tendon into a drill hole in the proximal tibia in 65 adult mongrel dogs. We applied two different doses of the bone morphogenetic protein to the tendon-bone interface in one limb using an absorbable type I collagen sponge carrier and only the collagen sponge to the contralateral (control) limb. The healed tendon-bone attachment was evaluated at serial times between 3 days and 8 weeks using radiography, histologic examination, and biomechanical testing. At all time points, histologic and radiographic examination demonstrated more extensive bone formation around the tendon with closer apposition of new bone to the tendon in the protein-treated limb than in the paired control limb. Biomechanical testing demonstrated higher tendon pull-out strength in the protein-treated side at all time points, with a statistically significant difference between the low-dose-treated side and the control side at 2 weeks. The histologic and biomechanical data suggested superior healing at the lower protein dose. This study demonstrated that bone morphogenetic protein can accelerate the healing process when a tendon graft is transplanted into a bone tunnel.

Animals↗
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The effect of cytokines on the proliferation and migration of bovine meniscal cells.

We determined the effect of cytokines on the proliferation and migration of cells isolated from the inner-third (white-white), middle-third (red-white), and outer-third (red-red) regions of bovine meniscus. Cells from the outer, or peripheral, region of the meniscus exhibited higher DNA synthesis in the presence of 10% serum compared with cells from the inner or central regions. Recombinant human platelet-derived growth factor-AB, hepatocyte growth factor/scatter factor, and bone morphogenic protein-2 stimulated DNA synthesis of all meniscal cells in a dose-dependent manner, with a two- to threefold maximal stimulation at 10 ng/ml. Cell migration was also stimulated by addition of cytokines. Platelet-derived growth factor and hepatocyte growth factor caused an increase in the migration of cells derived from all three zones, while interleukin-1 selectively stimulated the migration of outer-zone meniscal cells. Epidermal growth factor was much less effective and stimulated the migration of cells in the inner and outer zones by 40% to 50%, while bone morphogenic protein-2 and insulin-like growth factor-1 stimulated the migration of meniscal cells from the middle zone by 40% to 50%. The identification of cytokines that stimulate both the growth and migration of meniscal cells may provide new tools for modulation of meniscal healing.

Animals↗
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Stress fractures in 51 runners.

A prospective study was initiated in 1976 to investigate runners who are at risk for incurring stress fractures and how these fractures can be prevented. Fifty-one runners incurred 57 stress fractures. Tibial fractures were most common (25), followed by fibula (12) and metatarsal (8). Seven runners had previously sustained stress fractures, and six developed two stress fractures simultaneously. Five women over 30 years old had pelvic stress fractures. Stress fracture development was positively correlated with the presence of pes planus, weekly training distances greater than 20 miles, hard training surfaces, and training regimen modifications. The incidence did not correlate with generalized musculoskeletal laxity or tightness. Forty-four of 51 patients had initially positive roentgenograms. Five of five bone scans were positive. The average duration of rest before running was resumed was 7.4 weeks.

Adolescent↗
PubMedDate not supplied

Meniscal lesions associated with anterior cruciate ligament injury.

The menisci frequently are injured during anterior cruciate ligament (ACL) injury or degenerate in a period of several years. The meniscus, in addition to transferring force across the joint, prevents tibial displacement on the femur if the ACL is injured. Ten per cent to 30% of the peripheral meniscus has circulation; healing can occur if a tear communicates with this region. Arthroscopic partial meniscectomy in irreparable tears can be helpful in some patients with meniscus-derived complaints. Total meniscectomy should be avoided in ACL insufficient knees when possible. Accurate meniscal reattachment with ligamentous reconstruction should restore knee stability.

Animals↗