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Biomedical subjects

R F Warren

Publications and source records attributed to R F Warren.

At least 55 records · Page 3Linked to original sources
PubMed1997

Suprascapular neuropathy. Results of non-operative treatment.

We retrospectively reviewed the results of non-operative treatment of suprascapular neuropathy in fifteen patients seen between November 1983 and February 1991. The clinical diagnosis was confirmed with electrodiagnostic studies. The treatment consisted of a program of physical therapy to improve the range of motion of the shoulder and to strengthen the surrounding muscles. The average duration of follow-up was three years and eleven months (range, one year to eight years and ten months). The latest evaluation included electrodiagnostic studies of the affected extremity and dynamic isokinetic testing of both upper extremities. The result was excellent for five patients and good for seven. The three remaining patients had operative treatment because of persistent symptoms; one of these patients had an excellent result, one had a good result, and one had a poor result. The results suggest that, in the absence of a well defined lesion producing mechanical compression of the suprascapular nerve, suprascapular neuropathy should be treated non-operatively.

Adolescent↗
PubMed1997

Biomechanical evaluation of the medial collateral ligament of the elbow.

UNLABELLED: Anatomical dissection and biomechanical testing were used to study twenty-eight cadaveric elbows in order to determine the role of the medial collateral ligament under valgus loading. The medial collateral ligament was composed of anterior, posterior, and occasionally transverse bundles. The anterior bundle was, in turn, composed of anterior and posterior bands that tightened in reciprocal fashion as the elbow was flexed and extended. Sequential cutting of the ligament was performed while rotation caused by valgus torque was measured. The anterior band of the anterior bundle was the primary restraint to valgus rotation at 30, 60, and 90 degrees of flexion and was a co-primary restraint at 120 degrees of flexion. The posterior band of the anterior bundle was a co-primary restraint at 120 degrees of flexion and a secondary restraint at 30 and 90 degrees of flexion. The posterior bundle was a secondary restraint at 30 degrees only. The reciprocal anterior and posterior bands have distinct biomechanical roles and theoretically may be injured separately. The anterior band was more vulnerable to valgus overload when the elbow was extended, whereas the posterior band was more vulnerable when the elbow was flexed. The posterior bundle was not vulnerable to valgus overload unless the anterior bundle was completely disrupted. The intact elbows rotated a mean of 3.6 degrees between the neutral position and the two-newton-meter valgus torque position. Cutting of the entire anterior bundle caused an additional 3.2 degrees of rotation at 90 degrees of flexion, where the effect was greatest. CLINICAL RELEVANCE: Physical findings in a patient who has an injury of the anterior bundle may be subtle, and an examination should be performed with the elbow in 90 degrees of flexion for greatest sensitivity. As the anterior bundle is the major restraint to valgus rotation, reconstructive procedures should focus on anatomical reproduction of that structure. Parallel limbs of tendon graft placed from the inferior aspect of the medial epicondyle to the area of the sublimis tubercle will simulate the reciprocal bands of the anterior bundle. Temporary immobilization with the elbow in flexion may relax the critically important anterior band of the reconstruction during healing.

Biomechanical Phenomena↗
PubMed1997

A self-administered questionnaire for assessment of symptoms and function of the shoulder.

A self-administered questionnaire was designed to assess the severity of symptoms related to and the functional status of the shoulder. It includes domains of global assessment, pain, daily activities, recreational and athletic activities, work, satisfaction, and areas for improvement. Each domain is graded separately and is weighted to arrive at the total score. The over-all scale and each domain were prospectively tested for validity, reliability, and responsiveness to clinical change. One hundred patients who were seen for evaluation of the shoulder were enrolled in the study. The validity of the scale was demonstrated by moderate-to-high correlation of the domains and individual questions of the Shoulder Rating Questionnaire with those of the Arthritis Impact Measurement Scales 2. Validity was supported further by significant correlation of the scores in each domain with the level of satisfaction in that domain and by significantly lower scores in domains that patients selected as areas important for improvement. The over-all scale and each domain were internally consistent (Cronbach alpha, 0.71 to 0.90). Reproducibility was evaluated by repeated administration of the questionnaire after a mean of three days to forty patients whose condition was clinically stable. Reproducibility of the over-all questionnaire and individual domains was excellent (Spearman-Brown index, 0.94 to 0.98). Individual questions were reproducible, with a weighted kappa value of more than 0.7 for each. Responsiveness was evaluated by comparison of the preoperative and postoperative scores of thirty patients who had a satisfactory result one year after an operation on the shoulder. The over-all Shoulder Rating Questionnaire and each domain were responsive to clinical change as demonstrated by favorable standardized response means (range, 1.1 to 1.9) and indices of responsiveness (range, 1.1 to 2.0). Similar analysis performed for individual diagnostic groups supported the validity, reliability, and responsiveness of the questionnaire in each group. The self-administered shoulder questionnaire was found to be valid, reliable, and responsive to clinical change. These qualities should make it a useful instrument for the prospective assessment of the outcome of treatment of disorders related to the shoulder.

Activities of Daily Living↗
PubMed1996

Arthroscopic assisted rotator cuff repair: results using a mini-open deltoid splitting approach.

Out of 78 patients identified who underwent mini-open cuff repair, 64 were interviewed and returned a detailed questionnaire and 47 returned for a physical examination. Their average age was 64 years (31 to 85 years); and the average follow-up was 29.2 months (range, 12 to 65 months). The average tear size was 8 cm2. Preoperatively, all patients complained of pain and weakness. Ninety-six percent of patients displayed positive impingement signs preoperatively compared with 16% postoperatively. Active elevation increased significantly (P < .05) from 129 degrees to 166 degrees. At the time of follow-up there was no significant difference between active elevation in the operative and contralateral shoulders (P > .05). Weakness was detectable by physical examination in 83% of patients initially, and in 22% at the time of the final examination. The average pain and function scores improved significantly. Eighty-nine percent were satisfied with the results of their surgery. Three patients required further surgery on their shoulder. We found no correlation between cuff tear size and final Hospital for Special Surgery shoulder score.

Adult↗
PubMed1996

Arthroscopic Bankart repair using a degradable tack. A followup study using optimized indications.

Arthroscopic Bankart repair using degradable polymers is a relatively new procedure. Initial reports describing results among the first patients treated for instability of the shoulder using degradable tacks found rates of recurrent instability significantly higher than those for open repair procedures. A 21% postoperative recurrence rate was reported in the initial group of 62 patients studied. Modifications of the operative procedure and, more importantly, the indications for the procedure have led to substantially improved results. Using the following indications, a 2-year followup group of patients was found to have a 10% recurrence of instability rate: (1) traumatic instability, which primarily was anterior, unidirectional; (2) presence of a Bankart lesion; (3) presence of a robust inferior glenohumeral ligament; and (4) minimal to mild amount of bony erosions present at the glenoid. It is concluded that with more precise patient selection, arthroscopic stabilization using a degradable polymeric tack can provide high levels of patient satisfaction with low rates of recurrence.

Adult↗
PubMed1996

MR imaging of meniscal allografts: correlation with clinical and arthroscopic outcomes.

PURPOSE: To correlate magnetic resonance (MR) imaging findings after meniscal transplantation with those at clinical, arthroscopic, and histologic examination. MATERIALS AND METHODS: Twenty-four patients (29 menisci) underwent MR imaging after meniscal transplantation. Nineteen patients underwent arthroscopy, and the peripheral capsular attachment, degenerative areas, or both were sampled for biopsy. MR findings were correlated with those at clinical, arthroscopic, and histologic examination. RESULTS: MR imaging enabled accurate assessment of allograft attachments. Fragmentation and frank extrusion were associated with full-thickness chondral loss. Allograft degeneration, indicated by an increase in signal intensity, was seen with moderate and severe chondral wear. Clinical results were worse with meniscal extrusion, with complaints of locking. Patients with mild fragmentation reported pain without locking. Histologic examination of excised allografts revealed myxomatous degeneration without immunologic reaction. CONCLUSION: MR imaging can help assess allograft placement and articular cartilage and enable differentiation of fragmentation from extrusion. Preoperative assessment of articular cartilage is important to identify patients who may be at risk for failure.

Adult↗
PubMed1996

Labral injuries: accuracy of detection with unenhanced MR imaging of the shoulder.

PURPOSE: To prospectively assess the accuracy of unenhanced magnetic resonance (MR) imaging in the detection and localization of labral injuries. MATERIALS AND METHODS: One hundred three patients with clinically suspected shoulder injuries were prospectively examined with unenhanced MR imaging. A combination of gradient-echo and high-resolution fast-spin-echo axial pulse sequences were used. Surgical correlation was obtained in all patients. RESULTS: At surgery, 37 torn anterior, 36 torn superior, and 19 torn posterior labral were identified. The sensitivity for detection of these tears with MR imaging was 100%, 86%, and 74%, respectively; the specificity was 95%, 100%, and 95%, respectively. Overall, unenhanced MR imaging was 95% accurate in the detection of labral injuries. CONCLUSION: With appropriate pulse sequences, unenhanced MR imaging of the shoulder is an accurate technique for the detection and localization of labral injuries.

Adult↗
PubMed1996

An arthroscopic technique for anterior stabilization of the shoulder with a bioabsorbable tack.

Arthroscopically assisted repair of the anterior aspect of the labrum with use of a bioabsorbable tack was performed in fifty-two consecutive patients who had chronic anterior instability of the shoulder. The average age of the patients was twenty-eight years (range, sixteen to fifty years). The etiology of the instability was a traumatic injury in forty-nine patients; twenty-six of those injuries were sustained during participation in a contact sport. Fifty shoulders had a Bankart lesion. The patients were evaluated at an average of forty-two months (range, twenty-four to sixty months) after the procedure. Forty-one (79 per cent) of the patients were asymptomatic and were able to participate in sports without restriction. The repair was considered to have failed in eleven (21 per cent) of the patients. In four of them, the failure resulted from a single traumatic reinjury during participation in a contact sport, and three of these reinjuries were treated nonoperatively. The remaining seven failures occurred atraumatically. Eight patients had an open glenoid-based capsulorrhaphy as a consequence of recurrent instability. At the reoperation, no evidence of the tack was found in any patient. In seven patients, the Bankart lesion had completely healed, and the anteroinferior aspect of the capsule was patulous. Anterior stabilization of the shoulder with a bioabsorbable tack may be indicated for patients who have anterior instability but do not need a capsulorrhaphy or capsular imbrication to reduce the joint volume.

Adolescent↗
PubMed1996

Nitric oxide: an important articular free radical.

Nitric oxide is a small molecule that is synthesized by a family of enzymes, the nitric oxide synthases, and is overproduced in rheumatoid arthritis and osteoarthrosis. The aim of this investigation was to elucidate the potential sources of nitric oxide in joint tissues and to determine if the production of nitric oxide could be inhibited by dexamethasone or methotrexate, two agents that inhibit other forms of inducible nitric oxide synthase. Methotrexate inhibits the synthesis of biopterin, which is a co-factor for nitric oxide synthase. Explants of human and bovine cartilage and cultured chondrocytes released large amounts of nitrite, the stable end product of nitric oxide, when stimulated with endotoxin, interleukin-1 beta, or tumor necrosis factor-alpha. The production of nitrite was time-dependent and endotoxin, interleukin-1 beta, and tumor necrosis factor-alpha dose-dependent and was inhibited by the nitric-oxide-synthase inhibitors N omega-nitro-L-arginine methyl ester and aminoguanidine. The inducible nitric oxide synthase in bovine chondrocytes was calcium-dependent and was inhibited by high concentrations of methotrexate or dexamethasone. No constitutive nitric-oxide-synthase activity and little or no inducible nitric-oxide-synthase activity were demonstrable in explants or cell cultures derived from menisci. Fresh explants of bovine articular synovial tissue constitutively released nitrite that was inhibited by N omega-nitro-L-arginine methyl ester, but the release could not be enhanced by endotoxin, interleukin-1 beta, or tumor necrosis factor-alpha. There was no constitutive or inducible production of nitrite by explants or cells derived from the synovial tissue or shoulder capsule of a human or by explants or cells derived from canine anterior cruciate, posterior cruciate, medial collateral, lateral collateral, or patellar ligaments. Taken together, these results indicate that chondrocytes represent the major source of inducible nitric oxide synthase and nitric oxide during inflammation or infection of a joint.

Animals↗
PubMed1996

Meniscal repair using the outside-to-inside technique.

Research during the past decade has elucidated the structure and function of the knee joint meniscus, and both clinical and experimental studies have demonstrated the importance of this structure. Recent advances, such as the use of an exogenous fibrin clot, have allowed preservation of an increasingly greater proportion of injured menisci. The success of these methods will be established only by long-term follow-up studies demonstrating a lower incidence of progression to degenerative joint disease. It is hoped that an increasing understanding meniscal fibrochondrocytes biology and response to injury will result in the development of novel therapeutic strategies for repair of the injured meniscus. Basic studies clearly have demonstrated that meniscal fibrochondrocytes possess intrinsic repair capability. Both in vitro cell culture studies and in vivo animal models have provided the basic scientific foundation for the use of fibrin clot in tears in the avascular portion of the meniscus. The use of fibrin clot has allowed further expansion of the proportion of meniscal tears that are potentially reparable. Tears in the central, avascular zone of the meniscus, formerly thought to be irreparable, now may undergo repair with an enhanced opportunity for healing. The factors associated with a good prognosis in the meniscal repair include acute tear; peripheral tear; a stable knee; and the presence of serum or factors derived from serum, such as the presence of a fibrin clot, or vascular access channel, or hemarthrosis. Cell culture and molecular biologic techniques currently are being used to improve our understanding of meniscal biology. Particular challenges for future research include determination of the source of the reparative cells in meniscal repair, exploration of the biomechanical properties of the reparative tissue, and demonstration of the potential use of growth factors in meniscal healing. A further potential use of fibrin clot in the future is as a carrier vehicle both for the delivery of growth factors to injured meniscal and for the transplantation of autogenous fibrochondrocytes in meniscal defects. Other avenues of investigation include the use of cytokines to enhance meniscal healing, studies of meniscal replacement with allografts and collagen-based prostheses for meniscal regeneration, and the potential to augment meniscal cell proliferation and matrix synthesis by gene therapy techniques.

Animals↗
PubMed1996

Glenohumeral joint stability. Selective cutting studies on the static capsular restraints.

The glenohumeral joint relies on static and dynamic contributions of the local soft tissues to maintain joint stability. Dynamic stabilizers consist of the local musculature (the rotator cuff and periscapular muscles), whereas static stabilizers include the glenoid labrum and associated capsuloligamentous components. The functional interaction of static and dynamic components is complex and not completely understood. Selective cutting studies have been done to define the effect of sectioning various static components on resultant glenohumeral translation. These studies have played a pivotal role in the understanding of static factors controlling shoulder stability: the anatomic variability in capsuloligamentous anatomy has been recognized, and the complex interaction among various regions of the shoulder capsule and their labral attachment sites has been shown. Additionally, it has been recognized that the function of the capsuloligamentous restraints is highly dependent on arm position.

Biomechanical Phenomena↗
PubMed1995

Arthroscopic fixation of superior labral lesions using a biodegradable implant: a preliminary report.

Twenty-two patients were treated for symptomatic lesions of the superior glenoid labrum in association with instability of the tendinous insertion of the long head of the biceps brachii. A biodegradable implant was used to fix the labrum to the bony glenoid using an arthroscopic technique. At 2-year average follow-up, satisfactory results were obtained in 86% of the patients. Two patients, both of whom had undergone concomitant subacromial decompression, continued to complain of pain after the procedure; 3 patients had restricted motion postoperatively, and 1 required manipulation under anesthesia. Twelve of 13 overhead athletes were able to return to full premorbid function. Arthroscopic fixation of unstable lesions of the superior labrum led to a resolution of symptoms in the majority of patients. There were no complications related to the use of the biodegradable implant.

Adolescent↗
PubMed1995

Symptomatic ossification of the tibiofibular syndesmosis in professional football players: a sequela of the syndesmotic ankle sprain.

Ankle syndesmosis sprains are common injuries in collegiate and professional football. Several reports have documented that patients with syndesmosis injuries require a longer time to return to full athletic participation than patients with lateral ankle sprains. Here we present the cases of two professional football players with ankle pain secondary to syndesmosis ossification following documented syndesmosis ankle sprains. Both patients eventually required resection of the heterotopic ossification to allow a pain-free return to football. We conclude that syndesmosis ossification may be symptomatic in some patients, and surgical excision of the ossification may be required to allow an asymptomatic return to sports.

Ankle↗
PubMed1995

Effect of lesions of the superior portion of the glenoid labrum on glenohumeral translation.

Lesions of the superior portion of the glenoid labrum were created in seven cadaveric shoulders. The shoulders were mounted on a special apparatus attached to a servocontrolled hydraulic materials-testing device. Sequential fifty-newton anterior, posterior, superior, and inferior forces and a twenty-two-newton joint compressive load were applied to the shoulders. In addition, a fifty-five-newton force was applied to the tendon of the long head of the biceps brachii. The shoulders were tested in seven positions of glenohumeral elevation and rotation. An isolated lesion of the anterosuperior portion of the labrum, which did not involve the supraglenoid insertion of the biceps brachii, had no significant effect on anteroposterior or superoinferior glenohumeral translation, either with or without application of the fifty-five-newton force to the biceps brachii tendon. In contrast, a complete lesion of the superior portion of the labrum that destabilized the insertion of the biceps resulted in significant increases in anteroposterior and superoinferior glenohumeral translations. At 45 degrees of glenohumeral elevation, the complete lesion led to a 6.0-millimeter increase in anterior translation when the arm was in neutral rotation and to a 6.3-millimeter increase when the arm was in internal rotation; inferior translation also increased, by 1.9 to 2.5 millimeters. The increases in translation persisted despite application of a fifty-five-newton force to the long head of the biceps.

Biomechanical Phenomena↗