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Biomedical subjects

E L Flatow

Publications and source records attributed to E L Flatow.

At least 37 records · Page 2Linked to original sources

Split pectoralis major transfer for serratus anterior palsy.

The results of split pectoralis major tendon transfer (sternal head) for symptomatic scapular winging because of palsy of the serratus anterior muscle were reviewed. Eleven consecutive patients, whose average age was 34 years, had a duration of preoperative symptoms ranging from 12 to 60 months. Ten patients had electromyograms documenting a long thoracic nerve injury. Using an inferior axillary incision, the tendon of the sternal head of the pectoralis major is mobilized and transferred to the inferior angle of the scapula. The tendon transfer is reinforced with autogenous fascia lata. After surgery, a scapulothoracic orthosis is worn for 6 weeks, and restriction of vigorous activities is recommended for 6 months. At an average followup of 41 months, 10 of 11 (91%) patients had satisfactory results with significant improvement in function and reduction of pain. Each of these 10 patients had improved scapular tracking with no scapular winging or mild, dynamic winging at latest followup. One patient had an unsatisfactory result with a full recurrence of scapular winging secondary to noncompliance with the postoperative physical therapy regimen. The split pectoralis major tendon transfer provides a reasonable substitute for a paralyzed serratus anterior muscle in scapular stabilization. Strict adherence to technical principles and postoperative rehabilitation reliably leads to satisfactory clinical results.

Adult↗

Biochemical markers in synovial fluid identify early osteoarthritis of the glenohumeral joint.

The objective of this study on the glenohumeral joint was to assess the (1) accuracy of clinical diagnosis of osteoarthritis compared with arthroscopic diagnosis, and (2) the ability of biochemical markers in synovial fluid to detect osteoarthritis. Patients (96) were examined clinically and the preoperative diagnosis of osteoarthritis was recorded. At surgery (arthroscopy or arthroplasty), the glenohumeral joint was inspected for signs of osteoarthritis, and the joint osteoarthritis grade (I-IV) was recorded. At surgery, synovial fluid lavage was obtained from the joint, and later analyzed to determine levels of aggrecan components: total sulfated glycosaminoglycan and keratan sulfate epitope, link protein and the chondroitin sulfate epitope recognized by antibody 3B3 (3B3(-)). Compared with arthroscopic diagnosis of osteoarthritis, the results showed that the clinical diagnosis did not wrongly identify joints without osteoarthritis, and was always able to identify joints with advanced (Grade IV) osteoarthritis. Grade II osteoarthritis was rarely identified (10% of the time), and Grade III osteoarthritis was identified 50% of the time. Biochemical assessment of the synovial fluid showed that the catabolic markers (sulfated glycosaminoglycan, keratan sulfate and link protein) were elevated in fluids from joints with moderate (Grade III) and advanced osteoarthritis (Grade IV), and the 3B3(-) epitope was elevated in Grades II, III, and IV. These results show that arthroscopic diagnosis for osteoarthritis, of the glenohumeral joint is particularly useful for early and moderate osteoarthritis, where clinical (nonarthroscopic) diagnosis is poor, and that biochemical analysis of the synovial fluids corresponds well to arthroscopic diagnosis of shoulder osteoarthritis.

Arthroscopy↗

Glenohumeral stability. Biomechanical properties of passive and active stabilizers.

The shoulder is characterized foremost by its mobility and large range of motion. The glenohumeral joint is notable for its relative lack of bony constraint, relying heavily on the congruent articulating surfaces and surrounding soft tissue envelope for static and dynamic stability. Effective function in the articulation is achieved by a complex interaction between the various articular and soft tissue restraints. The rotator cuff muscles center the humeral head in the congruent glenoid fossa through the midrange of motion, when the capsuloligamentous structures are lax. However, incongruent joints, especially in positions of loading asymmetry (in external rotation), have larger translations that occur at the extremes of motion. Excessive translations are then effectively restricted by the mechanical properties of the inferior glenohumeral ligament. When the capsule is tightened anteriorly it results in an anterior tether and causes an associated posterior shift in contact on the glenoid. The posterior migration of the humeral head center and glenohumeral contact are again more pronounced in shoulders with reduced congruence. Additional studies of normal motion in different planes, the effects of rotator cuff pathology and dysfunction on the kinematics of the joint, proprioception of the capsule, and biomechanical tests of the inferior glenohumeral ligament and other components of the joint capsule at strain rates associated with injury, need to be conducted to understand the specifics of normal shoulder function and the pathophysiologic processes that occur during shoulder degeneration.

Biomechanical Phenomena↗

Shift of the posteroinferior aspect of the capsule for recurrent posterior glenohumeral instability.

Thirty-five shoulders in thirty-four patients were treated with a superior shift of the posteroinferior aspect of the capsule because of recurrent posterior glenohumeral subluxation and dislocation. The physical examination revealed three types of posterior instability in these patients preoperatively: unidirectional (six shoulders), bidirectional (posterior and inferior) (seven shoulders), and multidirectional (posterior and inferior dislocation with anterior subluxation) (twenty-two shoulders). Eleven shoulders had had previous operative procedures. At the time of the index operation, the most common abnormal findings in these shoulders were capsular redundancy and excessive volume of the glenohumeral joint. Complete detachment of the posterior aspect of the labrum was found in only four shoulders. There was no excessive glenoid retroversion in these patients. All thirty-four patients were available for follow-up at an average of five years (range, two to twelve and a half years) postoperatively. Over-all, the result for seventeen of the thirty-five shoulders was rated as excellent; eleven, as good; one, as fair; and six, as poor. Four shoulders became unstable again. Six of the seven unsatisfactory results were in shoulders that had had previous attempts at stabilization. A successful result was achieved in twenty-three of the twenty-four shoulders in which the superior shift of the posteroinferior aspect of the capsule was the initial repair.

Adolescent↗

Prosthetic design considerations in total shoulder arthroplasty.

Total shoulder replacements should, as far as possible, be designed after normal anatomy. A small mismatch in curvature between the humeral head and glenoid surfaces may reduce edge loading when the humerus translates on the glenoid, but may increase contact stresses caused by point loading. Modularity increases sizing options but decreases head size for a given soft-tissue space and introduces the risk of component dissociation. Releases and soft-tissue balancing at surgery, and rehabilitation afterwards, are more important than the type of glenohumeral prosthesis implanted.

Humans↗

Arthroscopic evaluation and treatment of the rotator cuff.

Arthroscopy has improved our diagnostic assessment of rotator cuff disease, especially in understanding patterns of articular surface partial-thickness tears. Arthroscopic subacromial decompression is a proven and reliable alternative to open acromioplasty. Despite continued controversy, most partial-thickness rotator cuff tears may be satisfactorily treated by arthroscopic debridement and decompression. The role for debridement and decompression without repair for full-thickness rotator cuff tears seems less than initially suggested, as several recent independent studies have documented results inferior to open repair. Arthroscopically assisted mini-open repair of small, full-thickness rotator cuff tears is a reliable procedure. Arthroscopic repair appears promising, but is not yet well enough documented to be considered a standard treatment.

Arthroscopy↗

Management of multidirectional instability.

Since 1980, several authors have reported successful treatment of multidirectional instability with use of the inferior capsular shift. Neer's initial report in a series of 32 patients noted only one unsatisfactory result. One decade later he reported that ¿more than 100 additional inferior capsular shifts have been done with similar satisfactory results.¿ The authors have reported preliminary results following 75 inferior capsular shifts performed in young athletes. Eighty-nine percent were able to return to their major sport while seventy-three percent maintained the same level of competitiveness. Seven patients (9.3%) reported a single episode of probable subluxation that was not followed by recurrent instability and did not affect the final result, whereas two patients (2.7%) dislocated postoperatively. Both of these cases were associated with a traumatic episode. The average loss of external rotation was 7 deg. Altchek and Warren reported their results following a T-plasty modification of the Bankart procedure for multidirectional instability in 42 shoulders. The patient population differed somewhat because 38 of the 42 cases had a Bankart lesion or detachment of the labrum and glenohumeral ligament complex. Patient satisfaction was rated excellent for 40 (95%) of the shoulders. The average loss of external rotation was 5 deg. Altchek and Warren noted that throwing athletes were unable to throw a ball with as much speed as before the operation. Additionally, 7 of 42 shoulders (16%) demonstrated 2+ or greater posterior instability postoperatively. There were four cases of symptomatic recurrent instability, one anterior and three posterior, while one patient required a posterior stabilization 2 years postoperatively. Recently Cooper and Brems' reviewed their series of 43 shoulders in 38 patients with a minimum 2-year follow-up after inferior capsular shift. Thirty-nine of 43 shoulders (91%) were rated by the patient as satisfactory with no recurrent instability. Postoperatively recurrent symptomatic instability developed in four patients (11%). Two of these patients required subsequent revision inferior capsular shifts and one of those went on to a humeral head replacement for arthritis of dislocation. The latter patient had received a prior Bristow procedure. Cooper and Brems concluded that the inferior capsular shift procedure provided satisfactory objective and subjective results. Failures and recurrences of symptomatic instability generally occurred in the early postoperative period less than 2 years following surgery. Their findings did not demonstrate a deterioration of the results, with a follow-up of 6 years. The authors recently reported the results after inferior capsular shift from classic multidirectional instability in 52 shoulders. Thirty-six shoulders were approached from the anterior side and 16 from posterior. All were completely immobilized in a brace for 6 weeks postoperatively. Forty-nine shoulders were observed over 2 to 11 years (average: 5 years). Satisfactory results were achieved in 94% of cases. Turkel and coworkers demonstrated that anterior glenohumeral stability is provided by varying regions of the capsule depending on arm position. Similarly, Warner and coworkers have recently demonstrated that inferior humeral translation is restrained by the anterosuperior capsule and ligaments with the arm at the side, and by the inferior capsule and ligaments with the arm in abduction. This is consistent with the clinical findings of Neer and Foster, who described inferior humeral translation with the arm at the side and with the arm in abduction in patients with multidirectional instability, and emphasized reducing redundant capsular volume on all sides at the time of surgical reconstruction. The capsular shift procedure eliminates laxity in the rotator interval, anterosuperior capsule, and anteroinferior capsule.(ABSTRACT TRUNCATED)

Arm Injuries↗

The use of arthroscopy in the treatment of resistant frozen shoulder.

Arthroscopy serves as a useful adjunct to manipulation under anesthesia in the treatment of resistant frozen shoulder. In this technique the shoulder is manipulated under interscalene brachial plexus block anesthesia, followed by arthroscopic examination and debridement of the glenohumeral joint and the subacromial space. The addition of arthroscopy allows the identification and treatment of associated pathology, such as impingement lesions and secondary subacromial space inflammation, calcific deposits, and acromioclavicular arthritis. Range of motion can also be increased by arthroscopically guided sectioning of the coracohumeral ligament. This treatment regimen has yielded overall satisfactory results in 25 (83%) of 30 shoulders in this series. The subgroup with diabetes mellitus fared less well than the other groups, with only 64% satisfactory results. While most patients with frozen shoulder will respond to nonoperative treatment, the technique of manipulation under anesthesia followed by arthroscopy offers a safe and reliable treatment for the resistant frozen shoulder.

Adult↗

Computer simulation of glenohumeral and patellofemoral subluxation. Estimating pathological articular contact.

Analytic stereophotogrammetry and an interactive computer graphics program were used to obtain first order assessments of joint contact patterns in patellofemoral and glenohumeral joints, simulating normal and abnormal articulations. Precise (90 microns accuracy) computer graphic representations of the humeral head, glenoid, patella, and femoral articular surfaces were obtained from cadaver knees and shoulders. These surface representations were then manipulated into an articulated position, and joint contact areas computed by a proximity criterion. Pathologic states were then simulated, and contact recomputed. Simulated glenohumeral subluxations dramatically reduced contact area, and focused it eccentrically on the glenoid rim. Simulated size mismatch of humeral heads to glenoids reduced contact area, producing a pattern of peripheral contact on the glenoid if the humeral head had a larger radius of curvature, and central contact on the glenoid if the humeral head had a smaller radius of curvature. At 30 degrees knee flexion, the patellofemoral joint demonstrated a broad distribution of contact along the distal aspect of the patella and proximal aspect of the trochlea. Simulated lateral tilt (5 degrees) and translation (5 mm) of the patella resulted in shift of the predominant contact area laterally, along with a drastic decrease in the contact area. These results have implications for prosthetic sizing and biomechanical modeling of the glenohumeral and patellofemoral joints, and in selecting models for more rigorous empiric studies of joint contact. Furthermore, this technique allows a first order assessment of the effects of specific surgical reconstructions on articular mechanics.

Computer Graphics↗

Interscalene block for shoulder arthroscopy: comparison with general anesthesia.

Arthroscopic shoulder surgery can be performed under regional or general anesthesia. The objective of this study was to demonstrate that regional anesthesia has several benefits over general anesthesia for this type of surgery, particularly in the ambulatory patient. Forty patients received general anesthesia and 63 an interscalene block. The regional block was found to be safe and effective, with a high degree of patient acceptance. It provided excellent intraoperative analgesia and muscle relaxation. Postoperatively, regional anesthesia resulted in fewer side effects, fewer hospital admissions, and a shorter hospital stay than did general anesthesia.

Adolescent↗

Arthroscopic resection of the distal clavicle.

Painful conditions of the acromioclavicular joint without instability can be treated successfully with arthroscopic methods. The direct approach is best suited for isolated acromioclavicular pathology. It also can be used to address the acromioclavicular joint during shoulder arthroscopy and bursoscopy, but two additional acromioclavicular portals are needed. In patients with both subacromial and acromioclavicular joint pathology, the bursal approach to the acromioclavicular joint can be used. In some patients with narrow or medially inclined overriding clavicles, the distal clavicle is not easily resected with the bursal approach. The direct approach is an alternative in these situations. Either method has been shown to be an effective treatment and can return the patient to full activity much sooner than with a traditional open resection.

Acromioclavicular Joint↗

Tensile properties of the inferior glenohumeral ligament.

The tensile properties of the inferior glenohumeral ligament have been determined in 16 freshly frozen cadaver shoulders. The inferior glenohumeral ligament was divided into three anatomical regions: a superior band, an anterior axillary pouch, and a posterior axillary pouch. This yielded 48 bone-ligament-bone specimens, which were tested to failure in uniaxial tension. The superior band was consistently the thickest region, averaging 2.79 mm. The thickness of the inferior glenohumeral ligament decreased from antero-superiorly to postero-inferiorly. The resting length of all three anatomical regions was not statistically different. Total specimen strain to failure for all bone-ligament-bone specimens averaged 27%. Variations occurred between the three regions, with the anterior pouch specimens failing at a higher strain (34%) than those from the superior band (24%) or the posterior pouch (23%). Strain to failure for the ligament midsubstance (11%) was found to be significantly less than that for the entire specimen (27%). Thus, larger strain must occur near the insertion sites of the inferior glenohumeral ligament. Stress at failure was found to be nearly identical for the three regions of the ligament, averaging 5.5 MPa. These values are lower than those reported for other soft tissues, such as the anterior cruciate ligament and patellar tendon. The anterior pouch was found to be less stiff than the other two regions, perhaps suggesting that it is composed of more highly crimped collagen fibers. Three failure sites were seen for the inferior glenohumeral ligament: the glenoid insertion (40%), the ligament substance (35%), and the humeral insertion (25%). In addition, significant capsular stretching occurred before failure, regardless of the failure mode.

Aged↗

Quantitation of in situ contact areas at the glenohumeral joint: a biomechanical study.

Glenohumeral arthritis may result from abnormal articular mechanics, and shoulder reconstructive procedures often rely implicitly on the belief that the restoration of normal articular mechanics is required to obtain satisfactory clinical results. Despite this, limited knowledge of normal or pathologic glenohumeral joint articular mechanics and contact is available. This study uses a stereophotogrammetry technique to determine contact areas in normal cadaver glenohumeral joints with intact ligaments and capsule through a large range of motion using simulated forces of the four rotator cuff muscles and three deltoid heads. All shoulders were first elevated to their maximum elevation in the scapular plane at an external rotation (starting rotation = 40 +/- 8 degrees), which allowed each shoulder to attain its maximal elevation in the scapular plane, and then repeated at 20 degrees internal to this rotation. Contact areas consistently increased with increasing elevation until 120 degrees to an average of 5.07 cm2 before decreasing with further increased elevation to an average of 2.59 cm2 at 180 degrees of total arm elevation. At 20 degrees internal to the starting rotation, contact areas reached high values 60 degrees earlier (averaged 4.56 cm2 at 60 degrees of total arm elevation) and then remained fairly constant through 120 degrees before decreasing with further increased elevation to 2.51 cm2 at 180 degrees total arm elevation. With increasing elevation in the external starting rotation, humeral head contact dramatically migrates from an inferior region to a superocentral-posterior region while glenoid contact shifts posteriorly. When the humeral shaft is positioned 20 degrees internal to the starting rotation, humeral head contact shifts from inferocentral-anterior to superocentral-posterior regions. Simultaneously, a similar posterior shift in glenoid contact is observed. Furthermore, whereas only a small portion of the humeral head surface area is in contact in any given position, contact on the glenoid surface is much more uniformly distributed over its entire articulating surface.

Aged↗

Arthroscopic treatment of calcific tendinitis of the shoulder.

The results of arthroscopic treatment of chronic resistant calcific tendinitis of the shoulder in twenty-three patients were evaluated. Each patient had greater than 1 year of unsuccessful nonoperative management prior to arthroscopic surgery. The average age was 49 years (range 33-60) and average follow up was 26 months (range 12-47). Subacromial bursectomy was performed in all patients. Based on follow-up radiographs, thirteen patients had partial calcium removal while nine had complete removal of calcium. Results were graded as good in eleven patients (50%) with full motion and complete pain relief, satisfactory in nine (41%) patients with full motion and occasional episodes of pain, and unsatisfactory in two (9%) patients with persistent pain. Arthroscopic calcium removal and subacromial bursectomy are reasonable alternatives in the treatment of chronic calcific tendinitis resistant to conservative treatment.

Adult↗