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Biomedical subjects

R F Warren

Publications and source records attributed to R F Warren.

At least 163 records · Page 9Linked to original sources
PubMed1979

The anterior cruciate ligament: a technique of repair and reconstruction.

Both primary repair and late substitution of anterior cruciate ligaments can be accomplished by intra-articular methods. This principle is to provide temporary struts that are initially avascular but can later undergo revascularization and metaplasia to form a new ligament. The graft does afford initial support, however. An understanding of anatomic principles, suture placement, freedom of graft from impingement, avoidance of acute angular deviation of the graft, solid static stability, anatomic attachment points, and blood supply, is absolutely essential for success in this field of surgery.

Fascia Lata↗
PubMed1978

Injuries of the anterior cruciate and medial collateral ligaments of the knee. A retrospective analysis of clinical records--part I.

The difficulty in diagnosing and subsequently treating lesions of the anterior cruciate ligament (ACL) is demonstrated in a review of 136 cases. Twenty-one patients noted a "pop" at the time of injury and each had a lesion of the ACL. The mechanism of injury may be helpful. The commonly seen valgus external rotation injury was noted in 60% of the cases but internal rotation with hyperextension and/or hyperflexion were also reported. The anterior drawer sign, if present, increases the accuracy to 92.1%. Failure of early cast treatment occurred if the ACL was torn but not in lesions confined to the MCL. Early meniscectomy in the cruciate deficient patient did not alleviate the need for further surgery in this group. At surgery the medial meniscus was torn in 93/124 ligament injuries but in addition 14 tears of the lateral meniscus were found. Wound complications were frequent with infection (4.8%) always being associated with hematoma formation (9.5%).

Adult↗
PubMedDate not supplied

Arthroscopic acromioplasty: a 6- to 10-year follow-up.

Arthroscopic acromioplasty has become a common procedure for the treatment of chronic impingement syndrome. Short-term studies have consistently shown good results; however, long-term data have not previously been reported in the literature. Of 102 consecutive patients undergoing arthroscopic acromioplasty at our institution from 1984 to 1988, 82 patients (83 shoulders) were available for evaluation. The patients were reviewed after a mean of 8 years, 5 months from their original surgery. There were 16 failures (19%) with unsatisfactory results following surgery; 13 patients (15%) required further surgery to relieve persistent pain. Thirty-three percent of all patients previously involved in sports were unable to return to overhead and throwing sports due to pain and lack of power with throwing. Overall, 81% of patients in our series had good to excellent results after 6 to 10 years. To optimize the indications for the procedure, other causes of impingement, such as occult instability and degenerative joint disease, should be ruled out. Throwers may have difficulty returning to their sport at the same level of intensity, and should be addressed independently.

Acromion↗
PubMedDate not supplied

Potential pitfall of the EndoButton.

A clinical and cadaveric example show the EndoButton (Acufex Microsurgical Inc, Mansfield, MA), used for anterior cruciate ligament endoscopic fixation, flipping outside the extensor mechanism or vastus lateralis rather than flipping directly outside the lateral femoral cortex. This pitfall was caused by overdrilling the femoral socket beyond the recommended 6 mm and overadvancing the EndoButton beyond the required depth to flip the EndoButton. Overdrilling the femoral socket to a depth of 10 mm still allows the EndoButton to rest properly on the cortex without soft tissue interposition. Increasing angles of knee flexion at the time of Endobutton placement decrease the safe distance beyond the lateral femoral cortex for flipping without soft tissue interposition. There is also potential to flip the EndoButton within the substance of the vastus lateralis, but the flipping action is blunted and not discrete.

Anterior Cruciate Ligament↗
PubMedDate not supplied

Anterior cruciate ligament injury and patella dislocation: a report of nine cases.

Nine patients had combined anterior cruciate ligament (ACL) disruption and patella dislocation and underwent surgical reconstruction of one or both of these injuries. Six patients had both the ACL reconstructed and the patella realigned, and three had only the ACL reconstructed. Associated injuries were present in eight cases; these included meniscal tears in eight patients and medial collateral ligament injuries in two of these same patients. At final follow-up, at an average 19.7 months, examination revealed an average grade 1A Lachman and no pivot on all patients who underwent ACL reconstruction. No patients had hypermobile patellae or apprehension. One patient had a 4 degrees loss of extension and none had a loss of flexion. Two patients had continued anterior knee pain at final follow-up; one of these patients was the same person who had a loss of extension. None had recurrent instability of the ACL and none had recurrent instability of the patella.

Adolescent↗
PubMedDate not supplied

Acute elbow injuries in the National Football League.

We performed a retrospective review to evaluate acute medial collateral ligament injuries of the elbow in professional football players from 1991 to 1996 (5 seasons). There were 5 acute medial collateral ligament injuries in 4 players (1 player with bilateral involvement). All injuries occurred with the hand planted on the playing surface while a valgus or hyperextension force was applied to the elbow. There were 2 centers, both involved with long-snapping situations, 1 running back, and 1 quarterback. All elbows had valgus instability on physical examination. Despite this instability, all players were able to function without operative reconstruction of the medial collateral ligament. No evidence of valgus instability was seen at the time of follow-up (average, 3.4 years). Next, we reviewed all acute elbow injuries in the National Football League from the same 5-season period. Ninety-one acute elbow injuries were reviewed. Overall, there were 70 (76.9%) elbow sprains, 16 (17.6%) dislocation/subluxation patterns, 4 (4.4%) fractures, and 1 (1.1%) miscellaneous injury. Review of the acute elbow sprains revealed 39 (55.7%) hyperextension injuries, 14 (20%) medial collateral ligament injuries, 2 (2.9%) lateral collateral ligament sprains, and 15 (21.4%) nonspecific sprains. The epidemiology of the 14 medial collateral ligament injuries was studied in more detail. The 2 most common mechanisms of injury were blocking at the line of scrimmage (50%) and the application of a valgus force with the hand planted on the playing surface (29%). There were 8 linemen, 4 receivers, 1 running back, and 1 quarterback. All injuries were managed with nonoperative treatment. The average time lost was 0.64 games (range, 0 to 4). We report 19 acute medial collateral ligament injuries of the elbow in elite football players, 2 of whom are considered overhead throwing athletes, who were able to function at a competitive level without surgical repair or reconstruction, in contrast to baseball players, in whom the mechanics and demands may differ.

Adult↗
PubMedDate not supplied

Radiologic measurement of superior displacement of the humeral head in the impingement syndrome.

A method for directly measuring the position of the humeral head on the face of the glenoid in different positions of abduction of the arm was developed. We studied three subject groups: 12 patients with normal shoulders (group 1), 15 patients with stage II impingement syndrome (group 2), and 20 patients with rotator cuff tears or stage III impingement (group 3). The study consisted of a series of anteroposterior roentgenograms in the plane of the scapula with the arm in neutral rotation. Roentgenograms were obtained at 20 degrees intervals as the arm was elevated in the plane of the scapula from 0 degree to 120 degrees. Patients held a weight equal to 2 1/2% of body weight in the hand. The parameters measured were excursion of the humeral head on the glenoid face, expressed as the distance that the center of the head lies above or below the center of the glenoid, arm angle, scapulothoracic angle, and glenohumeral angle. For patients with normal shoulders (group 1), there was no significant change in position of the humeral head with arm elevation. In contrast, those with stage II impingement (group 2) had significant (p < 0.05) superior displacement of the center of the humeral head with arm elevation. Patients with rotator cuff tears (group 3) demonstrated a significant rise (p < 0.05) during the first 40 degrees of abduction. The average position of the humeral head in the two pathologic patient groups was superior (p < 0.05) to the average head position in the normal patient group. There was no significant difference in head position between patients with stage II impingement and patients with rotator cuff tear. The ratio of the glenohumeral angle to the scapulothoracic angle during abduction was calculated for our patient groups. In both patient groups, arm abduction had a larger scapulothoracic component than for normal shoulders. The superior migration of the humeral head is a probable result of cuff failure, either partial or complete.

Adult↗
PubMedDate not supplied

Capsular restraints to anterior-posterior motion of the abducted shoulder: a biomechanical study.

Twenty-three fresh-frozen cadaver shoulders free of degenerative arthritis or rotator cuff disease were tested biomechanically to quantitate the contribution of specific capsular structures to restricting anterior-posterior translation of the abducted shoulder. With the glenohumeral joint in 90 degrees of abduction on a servohydraulic control testing system, translation was measured in 30 degrees of forward flexion (with regard to the coronal plane of the scapula), 0 degree, and 30 degrees of extension while a 25 N anterior-posterior load was applied. Measurements were taken both in the intact (vented) shoulder and after selective cutting of different capsuloligamentous structures was performed. In the intact shoulder the largest anterior-posterior translation occurred in 0 degree of horizontal flexion and extension with regard to the scapular plane, with equal amounts of anterior and posterior translation noted. The primary anterior-posterior stabilizer of the abducted shoulder is the inferior glenohumeral ligament complex. The anterior band is the primary stabilizer in 30 degrees of horizontal extension and at 0 degree (neutral). The posterior band is the primary stabilizer in 30 degrees of horizontal flexion. This study quantifies for the first time the normal amount of anterior-posterior translation in the intact cadaveric shoulder model. In addition, it demonstrates the relative role of the anterior and posterior band of the inferior glenohumeral ligament complex in stabilizing the glenohumeral joint at 90 degrees of abduction, where most clinical instability of the shoulder occurs.

Adult↗
PubMedDate not supplied

The efficacy of cryotherapy in the postoperative shoulder.

We report the results of an outcome study that used visual analog scales to evaluate the efficacy of cryotherapy in the postoperative shoulder. This prospective study included 50 consecutive patients admitted to the hospital for at least one night after anterior shoulder stabilization, rotator cuff repair, or total shoulder replacement. The patients were randomized: 25 were fitted with a cryotherapy device in the operating room, and 25 were not. Otherwise, postoperative treatment was identical for the two groups, including types of analgesic agents given. Visual analog responses were converted to numeric values by simple measurement techniques. The scales assessed pain, comfort, sleep, analgesic use, and overall satisfaction. On the night of the operation the pain was less severe and occurred less often in the cryotherapy group. Those in the cryotherapy group slept better on the night of the operation and perceived the need to use pain medicine less often in comparison with those in the noncryotherapy group. By postoperative day 10 patients in the cryotherapy group reported their shoulders hurt less often and with less severity. Swelling was less, and shoulder movement hurt less during rehabilitation, enhancing the rehabilitative effort. Cryotherapy offers a number of benefits for care of patients in the immediate postoperative period.

Adolescent↗
PubMedDate not supplied

Role of the long head of the biceps brachii in glenohumeral stability: a biomechanical study in cadavera.

Ten cadaveric shoulders were tested to evaluate the effect of simulated contraction of the long head of the biceps brachii on glenohumeral translation. The shoulders were mounted on a special apparatus attached to a servo-controlled hydraulic testing device. Sequential 50 N anterior, posterior, superior, and inferior forces and a 22 N joint compressive load were applied to the shoulders. An air cylinder applied a constant force to the tendon of the long head of the biceps brachii. The shoulders were tested in seven positions of glenohumeral elevation and rotation. Application of a force to the long head of the biceps brachii resulted in statistically significant decreases in humeral head translation. The influence of the long head of the biceps was more pronounced at middle and lower elevation angles. When the shoulder was placed in 45 degrees of elevation and neutral rotation, application of a 55 N force to the biceps tendon reduced anterior translation by 10.4 mm (p = 0.001), inferior translation by 5.3 mm (p = 0.01), and superior translation by 1.2 mm (p = 0.004).

Analysis of Variance↗
PubMedDate not supplied

Humeral head osteonecrosis: clinical course and radiographic predictors of outcome.

Forty-two patients (65 shoulders) with osteonecrosis of the humeral head were reviewed. Minimal follow-up was 2 years or until shoulder arthroplasty was performed for persistent severe pain and disability not responsive to conservative treatment. Thirteen shoulders had surgery shortly after presentation, whereas 22 others initially treated conservatively required surgery. Thirty shoulders in 20 patients have been treated without surgery and were evaluated at an average of 10 years after initial presentation. Fifteen shoulders are doing satisfactorily, whereas 15 others are doing poorly. Overall, 37 (71%) shoulders had clinical progression of disease requiring shoulder arthroplasty or resulting in severe pain and disability. All had radiographic stage III, IV, or V, and 41 (85%) had articular surface incongruity of 2 mm or greater. Humeral head drilling was not effective in preventing clinical or radiographic progression in stage III.disease. Radiographic stages of III or greater and documented radiographic disease progression were significantly associated with a poor outcome.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Dissociation of modular humeral head components: a biomechanical and implant retrieval study.

In vivo dissociation of the Morse-taper of shoulder arthroplasty modular humeral components has been reported. The incidence of this complication appears to be approximately 1:1000. The objective of this study was to identify conditions that might affect the Morse-taper interface strength in humeral components. Mechanical tests were performed to load and dissociate humeral heads from the humeral stems (titanium). The effect of loading rate, load amplitude, and number of impactions was investigated. Dissociation force was measured after the taper was contaminated with water, oil, blood, and bone cement particles. The mean dissociation force after two impactions with a mallet was 2926 +/- 955 N. Dissociation force was linearly proportional to impaction force. Repetitive loading beyond two impactions did not significantly increase taper strength. Contamination of the taper with as little as 0.4 ml of fluid could prevent fixation of the taper.

Biomechanical Phenomena↗
PubMedDate not supplied

Hemiarthroplasty of the shoulder for rotator cuff arthropathy.

Sixteen patients underwent hemiarthroplasty for rotator cuff arthropathy between June 1989 and March 1992, and evaluations obtained before and after surgery in all patients were compared. A modular head large enough to articulate with the coracoacromial arch but not so large as to prevent approximately 50% of humeral head translation on the glenoid was used in these cases. Each patient was evaluated with Neer's limited goals rating scale after an average follow-up of 33 months (24 to 55 months). Ten patients were rated as successful and six as unsuccessful. Four of the six unsuccessful patients had undergone at least one attempt at rotator cuff repair with acromioplasty before the index procedure, and two of these four patients had deficient deltoid function after this rotator cuff surgery as a result of postoperative deltoid detachment. Also, three of these four patients who had previously undergone acromioplasty subsequently had anterosuperior subluxation after hemiarthroplasty. Hemiarthroplasty did not provide for a successful outcome in all patients with rotator cuff arthropathy. However, 10 of the 12 patients in this series with good deltoid function and an adequate coracoacromial arch were rated as successful by Neer's limited goals criteria. In addition, this study illustrates that formal acromioplasty carried out during attempts at rotator cuff repair in such patients may jeopardize the subsequent success of hemiarthroplasty.

Aged↗
PubMedDate not supplied

Shoulder kinematics with two-plane x-ray evaluation in patients with anterior instability or rotator cuff tearing.

The goals of this study were to define biplanar glenohumeral kinematics and glenohumeral-scapulothoracic motion relationships in normal patients with a two-plane radiograph series and then in patients with anterior shoulder instability or rotator cuff tear both before surgery and after surgical repair and postoperative rehabilitation. A two-plane radiographic series of x-ray films in the scapular and horizontal (axillary) planes was performed. With these films, measurements of the relationship between the centers of the humeral head and glenoid and measurements of the component contributions of glenohumeral and scapulothoracic motion to total arm abduction were made. Six normal adults underwent x-ray evaluation to establish normal control values. Kappa analysis was used to determine reliability of technique. Eighteen patients with confirmed anterior shoulder instability (group A) and 15 with confirmed rotator cuff tears (group B) were studied before surgery. Seven (39%) of 18 of the patients in group A and all 15 (100%) of the patients in group B demonstrated superior translation of the humeral head during scapular plane abduction. In the horizontal plane 14 (78%) of 18 patients in group A (instability) and none in group B (rotator cuff tear) demonstrated abnormal anterior translation of the humeral head on the glenoid. Both groups demonstrated altered glenohumeral-scapulothoracic motion relationships compared with the normal control group. Two years after surgery 12 patients from group A and 14 patients from group B were restudied. All of these patients had demonstrated abnormalities of humeral head translation before surgery. For group A 12 (100%) of 12 patients demonstrated normal glenohumeral kinematics in both planes after open anterior stabilization. For group B 12 (86%) of 14 patients demonstrated normal glenohumeral kinematics in both planes after open rotator cuff repair. In group A the altered glenohumeral-scapulothoracic motion relationships persisted, whereas in group B these relationships became normal.

Adolescent↗
PubMedDate not supplied

Effect of humeral head component size on hemiarthroplasty translations and rotations.

Glenohumeral translation and rotation were measured in 6 grossly normal, fresh frozen shoulder preparations while a manual load was applied to the humerus. The same tests (maximum elevation, total rotation, anterior/posterior (A/P) translation, and inferior translation) were repeated for each shoulder through 8 series: 1 with the shoulder intact, 1 with the shoulder vented, and 6 with progressively larger humeral head components after hemiarthroplasty. There was an inverse linear relation between humeral head component size and all 4 outcome variables. Replacing the native head with a component of equal diameter reduced elevation 20%, rotation 40%, A/P translation 50%, and inferior translation 60% in the vented shoulder. Replacing the native head with a component of equal effective volume decreased elevation 8%, rotation 20%, A/P translation 25%, and inferior translation 40% in the vented shoulder. Increasing humeral head component size decreased rotation, A/P translation, and inferior translation by similar percentages and elevation somewhat less. Humeral head component size is better described in terms of volume than in terms of diameter or offset.

Arthroplasty, Replacement↗
PubMedDate not supplied

Articular contact patterns of the normal glenohumeral joint.

The purpose of this study was to determine the articular contact patterns of the normal glenohumeral joint, and to correlate these findings with cartilage and subchondral bone architecture. We studied 10 normal shoulders of cadavers. We removed all soft tissues except the joint capsule and rotator cuff and then placed the shoulders on a testing apparatus that allowed freedom of translation in three planes. After the humerus was placed in a neutral position of rotation, articular contact patterns were measured with specially prepared prescale Fuji film so that it could be inserted between the joint surfaces. Articular contact was analyzed with 222 and 444 N of joint compressive load, and the humerus was positioned in scapular plane abduction of 0 degree, 45 degrees, and 90 degrees. The contact patterns were then digitized to determine percentage contact of the humeral head on the glenoid. We studied 12 additional cadaver shoulders with fine microradiographs and histologic techniques after we sectioned the glenoids in the anterior-posterior and superior-inferior planes. We then analyzed articular and subchondral architecture. We found that when the shoulder was adducted the contact area of the humeral head on the glenoid was limited to the anatomic region of the central glenoid known as the "bare area." This was histologically and radiographically an area of cartilage thinning and increased subchondral bone density. As the shoulder was abducted the articular congruity and percentage contact area increased. We concluded that there was a slight articular mismatch with the shoulder adducted in the normal shoulder. Histologic and radiographic studies suggested that the central bare area region of the glenoid was a region of increased compressive loading. As the shoulder was abducted the joint became more congruent and thus the contact area of the humeral head on the glenoid increased.

Aged↗