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Biomedical subjects

R G Pollock

Publications and source records attributed to R G Pollock.

At least 19 recordsLinked to original sources

Osteolysis of the distal clavicle: long-term results of arthroscopic resection.

PURPOSE: The purpose of this study was to evaluate the outcome of arthroscopic distal clavicle resection by the direct superior approach for treatment of isolated osteolysis of the distal clavicle. TYPE OF STUDY: Case series. MATERIALS AND METHODS: Forty-one shoulders in 37 patients underwent arthroscopic resection of the distal clavicle. Thirty-three patients were male and 4 female, with an average age of 39 years. All patients complained of pain localized to the acromioclavicular joint region. Symptoms began after a traumatic event in 18 shoulders and were associated with repetitive stressful activity in 23 shoulders. RESULTS: At an average follow-up of 6.2 years, 22 shoulders had excellent results, 16 had good results, and 3 were failures. All 3 failures occurred in patients with a traumatic etiology. CONCLUSIONS: Arthroscopic resection for osteolysis of the distal clavicle has results comparable to open excision with low morbidity. Patients with a traumatic etiology had slightly worse results compared with patients with a microtraumatic etiology.

Adult↗

Operative results of the inferior capsular shift procedure for multidirectional instability of the shoulder.

BACKGROUND: Neer and Foster previously described the inferior capsular shift procedure for treating multidirectional instability of the shoulder and reported preliminary results that were quite satisfactory. The purpose of our study was to perform a longer-term follow-up evaluation of the efficacy of the inferior capsular shift procedure for treating multidirectional instability of the shoulder. METHODS: An inferior capsular shift procedure was used to treat multidirectional instability of the shoulder in forty-nine patients (fifty-two shoulders). All patients had failed to respond to an exercise program. In this series, the operative approach (anterior or posterior) was based on the major direction of the instability, as determined by the preoperative history and physical examination and as verified by examination with the patient under anesthesia. In all of the patients, the inferior capsular shift was the primary attempt at operative stabilization. The repair consisted of a lateral-side (or humeral-side) shift of the capsule to reduce capsular redundancy and, when necessary, a reattachment of the avulsed labrum to the anteroinferior aspect of the glenoid. RESULTS: A redundant capsular pouch was seen in all of the shoulders in this series. In addition, detachment of the anteroinferior aspect of the labrum was found in ten shoulders and an anterior fracture of the glenoid rim was seen in two shoulders. At an average of sixty-one months (range, twenty-four to 132 months), results were available for forty-nine shoulders (forty-six patients). Thirty shoulders (61 percent) had an excellent overall result, sixteen (33 percent) had a good result, one (2 percent) had a fair result, and two (4 percent) had a poor result. Forty-seven (96 percent) of the forty-nine shoulders remained stable at the time of follow-up. Two of the thirty-four shoulders that had been repaired through an anterior approach began to subluxate anteroinferiorly again. None of the fifteen shoulders that had been repaired through a posterior approach had recurrent instability. Full function, including the ability to perform strenuous manual tasks, was restored to forty-five shoulders (92 percent). A return to sports was possible after thirty-one (86 percent) of the thirty-six procedures done in athletes; however, a return to the premorbid level of participation was possible after only twenty-five (69 percent) of the thirty-six procedures. CONCLUSIONS: The results in this series demonstrate the efficacy and the durability of the results of the inferior capsular shift procedure for the treatment of shoulders with multidirectional instability. The procedure directly addresses the major pathological feature - a redundant joint capsule. Similar results were seen with either an anterior or a posterior approach, and we continue to approach shoulders with multidirectional instability on the side of greatest instability. A postoperative brace was reserved for patients in whom a posterior approach had been used or in whom an anterior approach had involved extensive posterior capsular dissection (ten of the thirty-four shoulders treated with the anterior approach).

Adolescent↗

Comparison of arthroscopic and open revision decompression for failed anterior acromioplasty.

Thirty-six consecutive patients who underwent revision decompression for refractory subacromial impingement were studied retrospectively. Average interval from the primary decompression procedure to revision was 29 months. Eighteen patients underwent arthroscopic and 18 underwent open revision. Six (33%) patients in the arthroscopic group and 12 (67%) patients in the open group were workers' compensation cases. At an average follow-up of 26 months, 17 (94%) patients in the arthroscopic group and 8 (44%) in the open group were satisfied with their procedure. Comparing workers' compensation patients, 5 of 6 in the arthroscopic group and 4 of 12 in the open group were satisfied. For nonworkers' compensation patients, all 12 patients in the arthroscopic group and 4 of 6 in the open group were satisfied. Average pain scores and postoperative range of motion was improved in both groups. Dense subacromial scarring with thick, fibrous adhesions was present in all patients. Residual, prominent bone, or an acromial spur was found in 20 (56%) patients. Overall, revision arthroscopic subacromial decompression was superior to open revision. However, there were more workers' compensation patients in the open group. Workers' compensation patients fared worse for both groups, but a significant proportion (83%) of the arthroscopic group was satisfied. Since subacromial scarring may be the most important pathology, arthroscopy is less invasive, allowing earlier, unrestricted postoperative rehabilitation and proving more effective.

Acromion↗

The rotator cuff. Full-thickness tears. Mini-open repair.

Arthroscopically assisted rotator cuff repair, through a mini-open, deltoid-splitting approach, is an effective treatment for small- to medium-sized full-thickness tears of the rotator cuff. Advantages over traditional open repair include relative deltoid preservation, the ability to assess and treat coexisting intra-articular pathology, shorter hospitalization, reduced early morbidity, easier and quicker rehabilitation, and a smaller scar. Standard open repair is preferred for larger tears with a greater degree of tendon retraction or when the subscapularis tendon is involved in the tear.

Arthroscopy↗

The rotator cuff. Commentary.

To add clinical perspective to the articles of this two-issue collection, eight prominent shoulder surgeons discuss their approach to the treatment of rotator cuff disease. There is broad agreement in many areas, however, significant controversies remain.

Adult↗

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↗

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↗

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↗

Recurrent posterior shoulder instability. Diagnosis and treatment.

Recurrent posterior glenohumeral instability is regarded as a difficult problem to diagnose and treat. A careful history and physical examination are the most helpful tools in making this diagnosis. A positive posterior stress test, demonstrable posterior subluxation, and a sulcus sign are frequently present on examination. Special roentgenographic studies, such as the computerized arthrotomography (arthro-CT) scan, may be used in cases in which plain roentgenographs suggest bony glenoid abnormalities. When conservative therapy fails, there is no consensus on the operative treatment. Procedures that address the soft tissues, such as capsulorrhaphy and posterior labral repair, as well as those that alter the bony geometry of the joint, such as posterior bone blocks and glenoid or humeral osteotomies, have been described. Capsular laxity is the most common pathologic finding in the authors' experience, and they favor the use of a posterior-inferior capsular shift procedure to correct this problem. Augmentation of the repair with a posterior bone block is reserved for unusual cases, such as when glenoid hypoplasia is present or in certain revision situations.

Arthroscopy↗

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↗

Arthroscopic distal clavicle resection from a bursal approach.

We retrospectively reviewed 117 consecutive patients who underwent arthroscopic acromioclavicular joint (ACJ) arthroplasties. Only patients who underwent ACJ arthroplasties from a bursal approach in conjunction with subacromial decompression were included. Patients with isolated ACJ arthrosis treated with resection of the distal clavicle from a superior approach, isolated impingement with only undersurface distal clavicle debridement, prior surgery, or other shoulder pathology were excluded. Twenty-four patients met these rigid criteria for inclusion in the study. After an arthroscopic subacromial decompression, the distal clavicle was visualized and resected through a standard bursal approach. In addition, an anterosuperior portal was used in 50% of the patients to confirm adequate clavicle resection. Postoperative follow-up averaged 32.5 months (range, 24 to 70 months). Preoperative and postoperative pain were rated subjectively on a 5-point scale (1, incapacitating pain; 5, no pain). Operative reports and postoperative radiographs were reviewed to determine technical factors that may have influenced outcome. Seventeen patients had excellent results (71%), 4 good (16.5%), and there were 3 failures (12.5%). Average preoperative pain rating was 1.8 and was improved to 4.3 postoperatively. The average amount of clavicle resection was only 5.4 mm. Given smooth, even, and complete bone removal, the amount of bone resected did not correlate with outcome. Arthroscopic distal clavicle resection performed in conjunction with subacromial decompression gave excellent results, comparable to isolated ACJ procedures. In this series, additional use of an anterosuperior portal for more direct shaver placement and complete ACJ viewing allowed consistent bone resection and excellent results in a high percentage of patients.

Acromioclavicular Joint↗

Operative treatment of nonunions of the surgical neck of the humerus.

Twenty patients underwent surgical reconstruction for nonunion of fractures of the surgical neck of the humerus. Average time from injury to surgery was 10 months (range 4 to 14 months). The operation consisted of bone grafting combined with humeral head replacement in 10 cases and open reduction and internal fixation in 10 cases. Results, at an average follow-up of 51 months (range 24 to 124 months), were excellent in five (25%), satisfactory in six (30%), and unsatisfactory in nine (45%). Twelve nonunions resulted from fractures initially treated with close reduction; repair of these nonunions achieved by 67% excellent or satisfactory results. Eight nonunions resulted from fractures initially treated with internal fixation; repair of these nonunions achieved only 38% excellent or satisfactory results. Fifteen complications, 11 of which necessitated reoperation, occurred. Surgical reconstruction for nonunions of the surgical neck of the humerus usually results in significant improvement in pain but much more modest improvement in active motion and function. Surgery should be reserved for patients with significant symptoms and disability.

Activities of Daily Living↗

Glenohumeral arthroplasty for arthritis after instability surgery.

Seventeen patients who had osteoarthritis of the glenohumeral joint after surgery for glenohumeral instability underwent prosthetic replacement. Thirteen men and four women with an average age of 43 years were studied. The interval from the initial instability repair to prosthetic replacement averaged 16 years. Before the operation all patients had severe functional disability caused by pain and limited range of motion, especially external rotation. Twelve patients underwent total shoulder replacement, and five patients underwent humeral head replacement. At an average follow-up period of 3 years, 13 (77%) satisfactory results and four (23%) unsatisfactory results were obtained. Pain was relieved in 16 (94%) of the 17 patients. Range of motion improved by an average of 37 degrees of elevation and 53 degrees of external rotation. Previous surgery had distorted the anatomy, and special techniques were required to correct anterior soft-tissue contracture and to compensate for posterior glenoid bone loss.

Adult↗

Arthroscopic resection of the distal clavicle with a superior approach.

Forty-one patients (41 shoulders) with acromioclavicular joint disease refractory to conservative treatment underwent arthroscopic distal clavicle resection. Thirty-one men and 10 women with an average age of 32 years were studied. The dominant extremity was involved in 68% of the patients. At an average follow-up period of 31 months (range 24 to 49 months), 18 excellent, 16 good, and seven poor results were found. Twenty-seven (93%) of 29 shoulders with acromioclavicular arthritis or osteolysis of the distal clavicle went on to have satisfactory results compared with only seven (58%) of 12 shoulders with previous grade II acromioclavicular separations or acromioclavicular hypermobility. Total amount of bone removal did not correlate with success, if the resection was even. Five reoperations were done; one uneven resection was revised with arthroscopy, and four shoulders underwent acromioclavicular stabilization procedures. The high failure rate in patients with even subtle acromioclavicular instability (42%) suggests that in these cases formal stabilization with ligament reconstruction should be considered in addition to resection of the distal clavicle.

Acromioclavicular Joint↗