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Biomedical subjects

R F Warren

Publications and source records attributed to R F Warren.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Effect of joint compression on inferior stability of the glenohumeral joint.

UNLABELLED: To determine the relative importance of negative intraarticular pressure, capsular tension, and joint compression on inferior stability of the glenohumeral joint we studied 17 fresh, normal adult cadaver shoulders using a "3 degrees of freedom" shoulder test apparatus. Translations were measured in intact and vented shoulders while a 50-N superior and inferior directed force was applied to the shoulder. Three different joint compressive loads (22 N, 111 N, 222 N) were applied externally. Tests were performed in 3 positions of humeral abduction in the scapular plane (0 degree, 45 degrees, 90 degrees) and in 3 positions of rotation (neutral, maximal internal, and maximal external). After tests of the intact and vented shoulder, the glenohumeral ligaments were sectioned and tests were repeated. With minimal joint compression of 22 N, negative intraarticular pressure and capsular tension limited translation of the humeral head on the glenoid. Increasing the joint compressive load to 111 N resulted in a reduction of mean inferior translation from 11.0 mm to 2.0 mm at 0 degree abduction, from 21.5 mm to 1.4 mm at 45 degrees abduction, and from 4.5 mm to 1.2 mm at 90 degrees abduction. With a compressive load of 111 N, venting the capsule or sectioning of glenohumeral ligaments had no effect on inferior stability. CLINICAL RELEVANCE: Glenohumeral joint compression through muscle contraction provides stability against inferior translation of the humeral head, and this effect is more important than negative intraarticular pressure or ligament tension.

Adult↗
PubMedDate not supplied

Radiographic evaluation of glenohumeral kinematics: a muscle fatigue model.

The purpose of this study was to document the effect of muscle fatigue on glenohumeral kinematics. Twelve male volunteers without shoulder disease and with an average age of 27 years were studied. Glenohumeral anteroposterior radiographs were taken at 45 degrees intervals as the arm was abducted in the plane of the scapula from 0 degree to 135 degrees. This series of radiographs was performed both before and immediately after the subject performed a series of deltoid and rotator cuff fatiguing exercises. The average humeral head position or translation before and after muscle fatigue for each arm angle was compared. For all subjects, before fatigue, the position of the humeral head was below the center of the glenoid for all angles of abduction. There was essentially no change in position of the humeral head in the prefatigue state, as the arm was abducted from 0 degree to 135 degrees with no more than an average 0.3 mm of total humeral head excursion. After fatigue, excursion of the humeral head increased to an average of 2.5 mm between the tested positions. The position of the humeral head with the arm at 0 degree of abduction was lower or had migrated inferiorly compared with the rested state, with an average 1.2 mm significant increase in inferior translation. With the initiation of abduction, the humeral head demonstrated significant superior migration or translation in all positions tested. This result has important implications for conservative treatment of shoulder impingement and underscores the importance of rehabilitation to maximize the endurance and strength of the rotator cuff musculature.

Adult↗
PubMedDate not supplied

Revision shoulder stabilization: 2- to 10-year results.

We evaluated 43 patients who underwent revision shoulder stabilization between 1978 and 1992. Twenty-three shoulders in 23 patients had unidirectional anterior shoulder instability (group A), whereas 21 shoulders in 20 patients exhibited multiple directions of shoulder instability (group B). Within group A recurrent instability developed at a mean of 35.5 months after the initial stabilization. Recurrence was traumatic in 12 patients. Revision surgery included a Bankart repair in 19 patients (coupled with capsular shift in 15 and a Bristow in 1) and capsular shift alone in 4. Within group B recurrent instability developed at a mean of only 16 months after the initial stabilization and was traumatic in only 2 patients. Revision surgery included capsular shift in 11 patients, Bankart repair in 5, anterior/posterior graft reconstruction in 3, and posterior bone block in 2. All patients had significant capsular laxity. A Bankart lesion was found in only 24% of patients. The mean follow-up from revision was 77.3 months (range 24 to 196 months) in group A. The results were excellent in 8 patients, good in 7, fair in 4, and poor in 4. Three of the 4 failures, however, had undergone successful reoperation before follow-up, improving the number of good or excellent results to 18 (78%). In contrast, at a mean follow-up of 61.5 months, only 9 (39%) good or excellent results occurred in group B despite multiple reoperations. Four patients ultimately went on to have glenohumeral fusion. Revision shoulder stabilization is a reliable procedure for patients who have recurrent anterior instability; however, it is unpredictable in patients who have multidirectional instability, with surgical failure and reoperation occurring frequently.

Adolescent↗
PubMedDate not supplied

Thermal modification of collagen.

Shoulder capsular shrinkage has recently been proposed as a therapeutic modality in a select group of patients with instability. Basic science research studying the mechanism of collagen shrinkage and the effect of shrinkage on the tissue's mechanical properties is essential to define the ideal process by which to achieve optimal tissue shrinkage. Tissue shrinkage is a function of both time and temperature. This relationship was studied, and a model was derived to describe the relationship mathematically. Tissue shrinkage rate was extremely sensitive to temperature changes. The purpose of this study, was to shrink collagenous tissue thermally and then to measure the mechanical property changes as a function of tissue shrinkage. Uniaxial tensile testing of normal and heat-shrunken bovine tendon was carried out, and a model was developed to express the relationship between shrinkage and mechanical properties. We found that the mechanical properties decreased with increasing shrinkage, and that the maximal allowable shrinkage before significant material property changes occurred was between 15% to 20%. Ultrastructural analysis with transmission electron microscopy showed denaturation of the collagen fibrillar structure and provided direct support for the observed material changes.

Animals↗
PubMedDate not supplied

Mucoid degeneration of the anterior cruciate ligament.

A case of intraligamentous mucoid degeneration of the anteromedial band of the anterior cruciate ligament (ACL) is presented. The patient had knee pain without clinical or diagnostic evidence of instability. Isolated debridement of the anteromedial band resulted in immediate pain relief with rapid return to athletic activities without instability. We present this case to demonstrate the presence of intraligamentous mucoid degeneration in the ACL as a source of knee pain without instability. Partial ACL debridement did not preclude adequate knee stability.

Adult↗
PubMedDate not supplied

The effect of cytokines on the migration of fibroblasts derived from different regions of the canine shoulder capsule.

This study examined the effect of several cytokines on the chemotactic migration of fibroblasts derived from 3 different parts of the canine shoulder: the upper part of the medial glenohumeral ligament (equivalent to the anterior part of the inferior glenohumeral ligament of the human shoulder); the inferior part of the medial glenohumeral ligament (equivalent to the axillary pouch of the human shoulder); and the posterior capsule (equivalent to the thin posterior capsule in the human shoulder). Platelet-derived growth factor-AB stimulated the migration of all 3 cell types in a dose-dependent manner, with increases from 150% to 300% at 1 ng/mL to 500% to 700% at 10 ng/mL. Hepatocyte growth factor also stimulated the migration of all 3 cell types in a dose-dependent manner (130% to 310%). Insulinlike growth factor-1 increased the migration of all 3 types of fibroblasts by 160% to 250%. Bone morphogenic protein-2, interleukin-1, and transforming growth factor-b had no significant effect on migration of shoulder capsular fibroblasts. These data demonstrate that capsular fibroblasts are responsive to specific growth factors and suggest the potential for use of growth factors to augment healing and/or remodeling of the shoulder capsule.

Animals↗
PubMedDate not supplied

Correlation of radiographic and arthroscopic findings with rotator cuff tears and degenerative joint disease.

The purpose of this study was to identify early signs of rotator cuff tear and glenohumeral articular cartilage degeneration by using conventional radiography. A non-weighted anteroposterior oblique and a weighted active abduction view were evaluated for superior humeral migration and matching degenerative changes at the inferolateral acromion and superior aspect of the greater tuberosity in 40 patients who underwent shoulder arthroscopy. Measurements of the glenohumeral distance were performed. Surgical reports were reviewed to determine rotator cuff and glenohumeral articular cartilage status. Matching degenerative changes correlate with complete rotator cuff tear (P =.04); superior migration does not. Severe glenohumeral cartilage loss correlates with narrowing of the superior joint space on the anteroposterior oblique radiograph (P =.02) and with narrowing of the mid joint space on the active abduction view (P =.05). Both glenohumeral articular cartilage degenerative change and rotator cuff injury, before formation of typical sequelae of chronic rotator cuff tear, can be detected with the use of conventional radiography.

Adult↗
PubMedDate not supplied

Sarcoidosis presenting as cervical radiculopathy: a case report and literature review.

A unique case of sarcoidosis, presenting as a unilateral multilevel cervical radiculopathy without spinal cord compression, is discussed. The clinical presentation, along with the initial myelographic findings and emphasis on local compressive etiologies delayed the diagnosis. The aim of this report is to focus on this unique entity and to review its role in the differential diagnosis of patients with atypical cervical radiculopathy. A pleocytosis of cerebrospinal fluid, an increase in protein concentration, and hypoglycorrhachia support the diagnosis of spinal cord sarcoidosis. While the outlook for patients with spinal cord sarcoid is poor, improvement of neurologic deficits has been documented after steroid therapy. A review of the literature on sarcoid involvement of the spinal cord and roots is summarized.

Adult↗
PubMedDate not supplied

Management of unicompartmental arthritis in the anterior cruciate ligament-deficient knee.

There exists a group of patients who are difficult to manage because they have both anterior knee instability secondary to anterior cruciate ligament deficiency and unilateral degenerative joint disease. A large majority of these patients report a history of previous meniscal injury or meniscectomy after knee trauma at a relatively young age. Active patients who report symptomatic knee instability or pain associated with athletics or activities of daily living after conservative treatment may be indicated for surgery. Current endoscopic methods of anterior cruciate ligament reconstruction result in low patient morbidity, the elimination of anterior knee instability, and a timely return of function. Osteotomies about the knee joint are an effective means of treating unicompartmental knee arthrosis. Long-term studies have demonstrated that knee osteotomy is a good surgical option for patients with unicompartmental arthritis who are considered too young for total knee arthroplasty. We describe a comprehensive treatment approach to the patient with anterior cruciate ligament deficiency and isolated medial or lateral osteoarthritis. An assessment of pain symptoms, instability symptoms, and lower extremity alignment is used to formulate a treatment plan.

Activities of Daily Living↗
PubMedDate not supplied

Fractures about the orbit in professional American football players.

A retrospective review was performed of records for players who suffered fractures about the orbit during participation in officially sponsored activities of the National Football League from 1980 to 1997. Clinical information was obtained on 19 of 29 players who sustained orbital fractures. The most common signs and symptoms included decreased visual acuity (74%, 14), decreased eye movement (42%, 8), hyphema (37%, 7), and infraorbital numbness (21%, 4). The mechanisms of injury were a digital poke (74%, 14) and blunt facial trauma (26%, 5). There were significantly more orbital fractures than zygomatic fractures suffered by offensive linemen as compared with all other positions. Fifteen of 19 players were managed with surgical reconstruction; 4 players were treated nonoperatively. The mean time from injury to surgical procedure was 7.7 days (range, 0 to 42). The mean interval to follow-up was 45.6 months (range, 3 to 146). At follow-up examination, eight (53%) of the patients treated surgically still reported diplopia with upper field gaze. Three of the four patients treated nonoperatively were asymptomatic. The mean time lost from games or practice was 25 days (range, 5 to 56). Ultimately, 17 (89%) players with orbital fractures were able to return to full football activities. Two patients were unable to resume their careers because of residual visual impairment.

Adult↗
PubMedDate not supplied

The effects of time course after anterior cruciate ligament injury in correlation with meniscal and cartilage loss.

In this study, 130 consecutive patients with anterior cruciate ligament insufficiency who were undergoing ligament reconstruction underwent arthroscopic examination at the time of reconstruction, and any loss of meniscal or chondral integrity was documented in a systematic fashion. In these patients, a greater proportion of the medial meniscus was lost compared with the lateral meniscus (16% versus 5%). On average, 6 cm2 of the articular cartilage was damaged (5.2 cm2) or lost (0.8 cm2), with the area of damage and loss greatest on the medial femoral condyle. Patients whose injuries had occurred more than 2 years before the examination had more than sixfold greater cartilage loss and damage compared with those whose injuries had occurred within the past 2 months. Meniscal loss was associated with a threefold increase in cartilage damage or loss. The group of patients with meniscal loss whose initial anterior cruciate ligament injury occurred more than 2 years before examination exhibited 18 times the amount of cartilage loss or damage as did the group that had no meniscal loss and whose injury occurred less than 1 month before examination.

Adolescent↗
PubMedDate not supplied

Development and evaluation of an activity rating scale for disorders of the knee.

Reports of clinical studies of patients with knee disorders should routinely include their activity levels to enable comparison of treatment groups and to allow generalizability. The goal of this study was to develop and evaluate a new rating scale to measure activity levels of patients. We assessed reliability by administering the scale to 40 subjects on 2 separate occasions, 1 week apart. Validity was evaluated by comparing the activity rating on the new scale with that from other instruments that use activity level scales (concurrent construct validity) and also by correlating the score on the new scale with age (divergent validity). Patients easily understood the scale and were able to complete it in 1 minute. The reliability was high (intraclass correlation coefficient, 0.97). The scale also correlated well with existing activity rating scales: Spearman correlation coefficient for Cincinnati score, 0.67; for Tegner scale, 0.66; for Daniel scale, 0.52. The activity score was significantly inversely correlated with age (P = 0.002), indicating divergent validity. This instrument will facilitate generalizability of results and allow more accurate comparisons among patient groups in outcomes research in sports medicine.

Adolescent↗
PubMedDate not supplied

Motion loss after ligament injuries to the knee. Part I: causes.

Motion loss continues to be a difficult complication after ligament injury and surgery to the knee. A better understanding of the pathoanatomic causes of motion loss can lead to improved prevention and treatment strategies. When motion loss does occur, early recognition and appropriate treatment can be expected to restore motion and improve function in most patients. Treatment options, although varied, should improve outcome when implemented appropriately. This article is composed of two parts. The first part reviews the current concepts on definitions, incidence, and causes of motion loss. In the second part, to be published later, current strategies on prevention and treatment of motion loss after ligament injury to the knee are reviewed. Emphasis is placed on risk factors and prevention as well as on diagnosis and treatment. The article summarizes the latest information from the basic sciences as well as clinical studies on the problem of motion loss of the knee and attempts to provide a rational approach to these difficult clinical problems.

Humans↗
PubMedDate not supplied

Motion loss after ligament injuries to the knee. Part II: prevention and treatment.

This is the second part of a two-part review on motion problems after ligament injuries to the knee. The first part, published in the September/October 2001 issue, discussed normal and abnormal knee motion, terminology, risk factors, and pathoanatomy. The purpose of this article is to review current concepts on prevention and treatment of motion problems, summarizing the recent and pertinent studies that discuss this complicated clinical problem. The first part of this article will discuss the different classification schemes that have been published on motion loss of the knee. Prevention strategies will be discussed next, followed by early recognition. Finally, a discussion of the various treatment options and published results will be presented in detail, together with the authors' nine-step systematic surgical approach to the stiff knee.

Anterior Cruciate Ligament↗
PubMedDate not supplied

Clinical characteristics of patellar disorders in young athletes.

The clinical histories of 50 young athletes who complained of patellar instability or pain were analyzed, and their physical findings were compared to those of 50 controls. The patients were divided into three groups, based on their symptoms. Analysis of their physical findings confirmed the validity of these divisions. Those who complained of frank dislocation of the patella exhibited the most pronounced stigmata of quadriceps dysplasia, including vastus medialis deficiency and infrapatellar fat pad enlargement, and had increased general ligamentous laxity, increased mean patellar mobility, and out-facing patellae with concomitantly decreased Q angles in chronic, recurrent cases. Patients who complained of the classic patellar pain pattern, often called "chondromalacia patella," but who denied swelling were designated CMP. They had normal mean ligamentous laxity and mean patellar mobility, an increased incidence of in-facing patellae with concomitantly increased mean Q angle, and frequently palpable lateral patellofemoral bands. Patients who complained of pain and swelling had physical findings intermediate to the other two groups, and generally correspond to what is usually termed subluxation of the patella. They exhibited normal general laxity but increased mean patellar mobility, normal mean Q angle but an increased incidence of patellar infacing, and fat pad enlargement.

Adult↗
PubMedDate not supplied

Microvasculature of the human meniscus.

The microvascular anatomy of the medial and lateral menisci of the human knee was investigated in 20 cadaver specimens by histology and tissue clearing (Spalteholz) techniques. It was found that the menisci are supplied by branches of the lateral, medial, and middle genicular arteries. A perimeniscal capillary plexus originating in the capsular and synovial tissues of the joint supplies the peripheral 10-25% of the menisci. A peripheral, vascular, synovial fringe extends a short distance over both the femoral and tibial surfaces of the menisci but does not contribute any vessels to the meniscal stroma. The posterolateral aspect of the lateral meniscus adjacent to the popliteal tendon is devoid of penetrating peripheral vessels as well as a synovial fringe. The anterior and posterior horn attachments of the menisci are covered with vascular synovial tissue and appear to have a good blood supply.

Cartilage, Articular↗