Search PubMed⌕ Search

Biomedical subjects

R F Warren

Publications and source records attributed to R F Warren.

At least 91 records · Page 5Linked to original sources
PubMed1993

Chronic ankle instability as a cause of peroneal tendon injury.

Chronic lateral ankle pain and instability can be associated with a split in the peroneus brevis tendon. This case reports a peroneus brevis split that was centered over the sharp posterior edge of the fibula and was associated with laxity of the superior peroneal retinaculum, and chronic ankle instability. The mechanism of the split was easily demonstrated during surgery by everting the foot and pulling longitudinally on the peroneus longus tendon. The interrelationship of lateral ankle instability with superior retinacular laxity and resultant peroneus brevis splits can account for posttraumatic lateral ankle pain. Surgical treatment must identify and correct the underlying pathology and should attempt to repair or debride the peroneus brevis tendon, reconstruct the superior peroneal retinaculum, flatten the posterior edge of the fibula by removing the sharp bony prominence, and address any associated lateral ankle instability with either a modified Chrisman-Snook, Anderson, or modified Brostrom-Gould procedure.

Adult↗
PubMed1993

Supporting layers of the glenohumeral joint. An anatomic study.

Based on anatomic and surgical dissections, the anatomy of the shoulder region is described in terms of four layers that overlie and support the glenohumeral joint. Each layer envelops the glenohumeral joint on its anterior, lateral, and posterior aspects, and between each layer there is a plane for safe and easy dissection. Layer 1 is composed of the deltoid and pectoralis major muscle bellies with their overlying fascia and enveloping epimysium. Anteriorly, Layer 2 consists of the clavipectoral fascia, the conjoined tendon of the short head of the biceps and coracobrachialis, and the coracoacromial ligament. Posteriorly, Layer 2 is the dense posterior scapular fascia that overlies the infraspinatus and teres minor muscle bellies. It is continuous with the clavipectoral fascia around the lateral aspect of the proximal humerus. Deep to Layer 2, the subdeltoid bursa yields a dissection plane that encompasses the anterior, lateral, superior, and variably the posterior aspects of the glenohumeral joint. Layer 3 consists of the deep layer of the subdeltoid bursa and the underlying musculotendinous units of the rotator cuff, including subscapularis, supraspinatus, infraspinatus, and teres minor. Layer 4 is the capsule of the glenohumeral joint. This includes the glenohumeral ligaments and coracohumeral ligament. These four layers were present and consistent in each shoulder dissected. Significant variations were present only within the deepest layer (shoulder joint capsule). This system can serve as a learning tool and will provide a more organized approach to facilitate surgical dissection in the region.

Cadaver↗
PubMed1993

Arthroscopic shoulder stabilization. A role for biodegradable materials.

The use of metallic implants about the shoulder joint can be complicated by loosening, migration, and breakage of the implant. Bioabsorbable implants would be an ideal solution to this problem if their bioabsorption profile could be fine tuned to appropriately share stress with the healing tissues. The development of such an implant must satisfy four basic criteria: (1) The bioabsorbable implant must have adequate initial fixation strength to coapt the soft tissues to bone; (2) The implant's bioabsorption profile must enable it to retain satisfactory strength while the healing tissues are regaining mechanical integrity; (3) The implant must not bioabsorb too slowly or it will behave like its metal counterpart with breakage and migration; and (4) The implant must be made of materials that are completely safe: no toxicity, antigenicity, pyrogenicity, or carcinogenicity.

Arthroscopy↗
PubMed1992

Cellular repopulation of deep-frozen meniscal autografts: an experimental study in the dog.

This study evaluated the cellular repopulation of deep-frozen meniscal autografts. Medial menisci of adult dogs were excised, deep-frozen in liquid nitrogen (-196 degrees C) for 10 min, and orthotopically reimplanted into the joint. Deep-freezing was found to effectively kill all the cells within the meniscus as determined by the absence of Na(2)35SO4 incorporation. Following orthotopic replacement within the knee joint, menisci were repopulated with cells that seemed to originate from the adjacent synovium. These cells migrated over the surface of the meniscus and began to invade the deeper layers of the tissue. However, even after 6 months, the central core of the meniscus remained acellular. While the new cells appeared to modulate into cells that are similar in appearance to meniscal fibrochondrocytes, the exact phenotypic expression of these newly differentiated cells has yet to be determined. Histological alterations, as manifested by a loss of normal orientation of the collagen architecture of the superficial layers of the meniscus; was evident at 6 months and suggests that a remodeling phenomenon may be associated with the cellular repopulation. While biomaterial studies have not been carried out on these specimens, the morphologic alterations observed in the collagen orientation would suggest a possible alteration in the material properties of the repopulated meniscus. The clinical implication of this study is that the structural remodeling associated with the cellular repopulation of deep-frozen meniscal allografts may make the transplanted meniscus more susceptible to injury.

Animals↗
PubMed1992

Intraarticular fibrous nodule as a cause of loss of extension following anterior cruciate ligament reconstruction.

Loss of motion is a well-known complication following anterior cruciate ligament (ACL) reconstruction. We have found that loss of extension is more disabling than loss of flexion, and is a more common problem following arthroscopic assisted ACL reconstruction. We are reporting on a group of 21 patients who have developed restricted knee extension following ACL reconstruction utilizing either the central one-third of the patellar ligament or the hamstring tendons as an autogenous graft. The patients presented at an average of 4 months postoperatively with a clinical syndrome of loss of extension associated with pain at terminal extension, crepitus, and grinding with attempted extension beyond their limit. The consistent finding at arthroscopy was a fibrous nodule occupying the intercondylar notch, varying in size from 1 x 1 to 2 x 3 cm, and presenting a mechanical block to full extension. It appears that anterior placement of the graft, particularly on the tibia, results in injury to the graft and subsequent nodule formation. Removal of the nodule resulted in improvement of an average preoperative loss of extension of 11 degrees, to 3 degrees at surgery, and 0 degrees at 1 year follow-up. The average side-to-side difference in terminal extension at final examination, using the uninvolved limb for comparison, was 3 degrees. Histology was available for review on 19 of the 21 patients operated on. The consistent microscopic finding within the nodule was the presence of disorganized dense fibroconnective tissue that, with time, underwent modulation to fibrocartilage. It is postulated that this occurs in response to compressive loading of the nodule.

Adult↗
PubMed1992

CT of 338 active professional boxers.

Computed tomography (CT) was performed in 338 active professional boxers. CT scans were abnormal in 25 boxers (7%). The most common CT abnormality was brain atrophy (22 cases). Focal lesions of low attenuation consistent with posttraumatic encephalomalacia were noted in only three boxers. Boxers with abnormal CT scans did not differ from those with borderline or normal CT scans in regard to age, win-loss record, number of bouts, or history of an abnormal electroencephalogram. Thirty-seven boxers with borderline CT scans (49%) and 17 with abnormal CT scans (68%) reported a previous technical knockout (TKO) or knockout (KO), compared with only 89 (37%) of the 238 boxers with normal CT scans (P < .01). Brain atrophy was noted more frequently in boxers with a large cavum septum pellucidum (CSP) than in those with a small or no CSP (P < .05). Boxers with abnormal or borderline CT scans who experienced a TKO or KO were slightly older than those with normal CT scans and a history of a TKO or KO (P < .05).

Adolescent↗
PubMed1992

Complete knee dislocation without posterior cruciate ligament disruption. A report of four cases and review of the literature.

Complete knee dislocation usually causes disruption of both the anterior and posterior cruciate ligaments. Four cases of complete knee dislocation without posterior cruciate ligament (PCL) disruption are reported. All cases involved either anterior or anteromedial dislocation with anterior cruciate ligament disruption and collateral ligament injury, but without posterior cruciate disruption. This is an uncommon finding in complete dislocation of the knee. The PCL may occasionally be spared significant injury in anterior type dislocations, however, thus favorably affecting treatment options.

Adolescent↗
PubMed1992

Accessory head of the biceps brachii. Case report demonstrating clinical relevance.

Although anatomic variations in the origin of both the coracobrachialis or biceps brachii have been observed, there have been no previous reports of clinical relevance. In a 22-year-old man, recognition and mobilization of an accessory long head of the biceps brachii was necessary for adequate exposure of the shoulder joint dislocation through a deltopectoral incision.

Adult↗
PubMed1992

Modular hemiarthroplasty for fractures of the proximal part of the humerus.

A new biomodular prosthesis was used for the treatment of a displaced fracture of the proximal part of the humerus in twenty-two shoulders in twenty-two patients. The fractures were classified according to the Neer system; there were thirteen four-part, five three-part, and four head-splitting fractures. There were fifteen women and seven men, and the mean age was seventy years (range, forty-nine to eighty-seven years). The hemiarthroplasty was performed an average of eleven days (range, one to forty-five days) after the injury. The deltopectoral interval was used in all patients, and the prosthesis was implanted with cement in twenty of the shoulders. All of the patients participated in a supervised program of rehabilitation. The patients were followed for an average of thirty-six months (range, twenty-six to forty-nine months). Twenty of the twenty-two patients had a good or excellent result. The active forward elevation averaged 119 degrees; external rotation, 40 degrees; and internal rotation, to the twelfth thoracic vertebra. All of the patients except for the two who had a poor result had satisfactory relief of pain. The two patients who had a poor result had a successful revision with a modular prosthesis of the same design. The modular head could be removed, enabling the surgeon to gain access to the glenoid and to adjust the soft tissues. The over-all scores correlated inversely with the age of the patients and the interval from the injury to the operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Anatomy, histology, and vascularity of the glenoid labrum. An anatomical study.

We studied the gross, histological, and vascular anatomy of the glenoid labrum in twenty-three fresh-frozen shoulders from cadavera to demonstrate its cross-sectional anatomy, its microvascularity, and its attachments. The superior and anterosuperior portions of the labrum are loosely attached to the glenoid, and the macro-anatomy of those portions is similar to that of the meniscus of the knee. The superior portion of the labrum also consistently inserts directly into the biceps tendon, while its inferior portion is firmly attached to the glenoid rim and appears as a fibrous, immobile extension of the articular cartilage. The arteries supplying the periphery of the glenoid labrum come from the suprascapular, circumflex scapular, and posterior circumflex humeral arteries. In general, the superior and anterosuperior parts of the labrum have less vascularity than do the posterosuperior and inferior parts, and the vascularity is limited to the periphery of the labrum. Vessels supplying the labrum originate from either capsular or periosteal vessels and not from the underlying bone.

Adult↗
PubMed1991

Measurement reproducibility of two commercial knee test devices.

Objective evaluation of patients' knee motion using mechanical devices, whether for diagnostic purposes or for assessing rehabilitative procedures, requires that these devices be reproducible, in order to avoid errors independent of the patients' condition. This study prospectively evaluates the reproducibility of two commercial knee test systems, the KT 1000 Knee Ligament Arthrometer and the Genucom Knee Analysis System, by performing repeated measurements on twenty normal men. Average knee motion, between-subject variance, and within-subject variance were determined by performing repeat tests on the same day and one week later. No significant difference was found between measurements taken on the two different test days, but the within-subject variation was high. We found that larger applied forces or moments resulted in a larger variation in mean displacements. However, the percent variation about the mean (coefficient of variation) decreased with increasing applied loads. The coefficient of variation for the KT 1000 varied from 8 to 33% and for the Genucom, from 13 to 87%. On an individual basis, large variations were found in repeated measures for both devices. To minimize errors, we recommend that repeated tests be performed, higher forces and moments utilized, and specific flexion angles be used for each device and test. Even under these conditions, caution must be exercised when evaluating individual subjects.

Adult↗
PubMed1991

Contaminated patellar tendon grafts: incidence of positive cultures and efficacy of an antibiotic solution soak--an in vitro study.

The incidence of positive cultures after contamination of sterile patellar tendon grafts in an operating room environment was studied in 10 specimens. The grafts were dropped on the floor for 3 min and then cultured. Six of the 10 grafts (60%) had a positive culture at 10 days. To test the efficacy of an antibiotic solution on cleansing contaminated grafts, 10 additional grafts were dropped on the floor for 3 min. Before the grafts were cultured they were soaked in a sterile saline solution containing bacitracin (33.33 U/ml) and polymyxin B (333.33 U/ml) for 15 min. Thirty percent of these grafts (3 of 10) cultured positive at 10 days. In each case the bacterial contaminant was found to be sensitive to one of the antibiotic agents used in the cleansing solution. The results of this study suggest that although soaking contaminated grafts in this antibiotic solution for 15 min may reduce the incidence of positive cultures, it still results in a 30% incidence of nonsterile grafts.

Anterior Cruciate Ligament↗
PubMed1991

Extrusion of the medial meniscus.

Disruption of the anchoring points of the menisci of the knee has been hypothesized to result in subluxation of the affected meniscus from the articular surface. A case report of such an extrusion of the medial meniscus is presented. Medial subluxation of the meniscus from the tibiofemoral articulation occurred as a result of avulsion of the posterior horn with concomitant medial collateral and posterior cruciate ligament injuries.

Arthroscopy↗
PubMed1991

Meniscal repair.

Over the past several decades, scientific evidence has mounted to substantiate the vital role of the meniscus in the function of the knee. Total meniscectomy is rarely indicated and the pendulum of orthopedic popular opinion has swung toward new ways to preserve the injured meniscus. This article reviews the anatomy, blood supply, and function of the meniscus and also discusses the supporting scientific evidence, decision-making processes, and techniques for meniscal repair.

Arthroscopy↗
PubMed1991

Ligamentous control of shoulder stability based on selective cutting and static translation experiments.

The glenohumeral joint is a complex articulation with little inherent stability, capable of significant rotations. The capsuloligamentous structures play a critical static role in maintaining joint stability. Various components have been identified both anatomically and functionally, with their contributions varying depending on joint position and the direction of applied forces.

Humans↗
PubMed1991

T-plasty modification of the Bankart procedure for multidirectional instability of the anterior and inferior types.

Forty patients who had a diagnosis of multidirectional instability of forty-two shoulders had a modified Bankart operation in which a T-shaped incision was made in the anterior portion of the capsule, with advancement of the inferior flap superiorly and of the superior flap medially. All of the patients had been injured during athletic activities. Some degree of anterior labral injury was present in thirty-eight of the forty-two shoulders. Half of the patients had generalized ligamentous laxity. The patients were followed for an average of three years (range, two to seven years). Four patients had episodes of instability after the operation. Three had a single episode of posterior subluxation during throwing, one had recurrent posterior subluxation that subsequently was treated by posterior stabilization, and one had anterior subluxation while he was diving from a high board. The average loss of external rotation after the operation was 5 degrees with the arm at the side and 4 degrees with the arm abducted 90 degrees. Satisfaction of the patient was rated excellent for forty (95 per cent) of the shoulders, good for one shoulder, and fair for one shoulder. However, throwing athletes found that they were unable to throw a ball with as much speed as before the operation.

Adolescent↗
PubMed1991

Reconstruction of the chronically insufficient anterior cruciate ligament with the central third of the patellar ligament.

The results of reconstruction of the anterior cruciate ligament with the central third of the patellar ligament as a free, autogenous, non-vascularized graft were retrospectively reviewed at our institution. Eighty reconstructions in seventy-nine patients were evaluated after a minimum of two years. In forty-eight (60 per cent) of the knees, the reconstruction was augmented with an extra-articular lateral sling of iliotibial band. The patients were evaluated with a physical examination, a KT-1000 arthrometer, radiographs, a subjective questionnaire, and a revision of the scale of The Hospital for Special Surgery for rating ligaments. Postoperatively, seventy-six (95 per cent) of the eighty knees no longer gave way, and the pivot-shift test was negative in sixty-seven (84 per cent) of the knees. The average score on the ligament-rating scale was 93 points. All of the patients who had clinical instability at the time of the most recent follow-up had associated ligamentous instability that had not been appreciated or addressed at the time of reconstruction. Arthrometric evaluation revealed that the laxity differed by three millimeters or less from that of the untreated knee in sixty (76 per cent) of the treated knees. In the patient who had bilateral reconstruction, the laxity was the same in both knees. Seventeen patients, who had more than three millimeters of translation, also had additional related ligamentous instability, most commonly posterolateral instability and insufficiency of the medial collateral ligament. We think that major associated ligamentous instability predisposes the reconstruction to failure and should be corrected in conjunction with the reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗