Biomedical subjects

R G Pollock

Publications and source records attributed to R G Pollock.

27 records · Page 2Linked to original sources

PubMedDate not supplied

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↗

PubMedDate not supplied

Hemiarthroplasty for glenohumeral osteoarthritis: results correlated to degree of glenoid wear.

Thirty patients (31 shoulders) were retrospectively reviewed after hemiarthroplasty for glenohumeral osteoarthritis. Ten shoulders had primary osteoarthritis, and 21 shoulders had secondary osteoarthritis. Glenoid surface wear was evaluated and classified as either type I, concentric, (15 shoulders) or type II, nonconcentric, (16 shoulders). Postoperative results were reviewed with the American Shoulder and Elbow Surgeons' evaluation form, Neer classification, and the Constant score. Overall, 23 (74%) shoulders achieved satisfactory results, and 8 (26%) shoulders had unsatisfactory results. Results were similar in the primary and secondary osteoarthritis groups. Outcome correlated most significantly with the status of posterior glenoid wear. Patients with concentric, type I glenoids achieved 86% satisfactory results, whereas patients with nonconcentric, type II glenoids had only 63% satisfactory results. Although pain relief was similar in both groups, the unsatisfactory results were attributed to loss of forward elevation and external rotation in patients with type II glenoids. On the basis of these results hemiarthroplasty can be an effective treatment for both primary and secondary arthritis but should be reserved for patients with a concentric glenoid, which affords a better fulcrum for glenohumeral motion.

Adult↗

PubMedDate not supplied

The incidence of ganglion cysts and other variations in anatomy along the course of the suprascapular nerve.

When the diagnosis of suprascapular nerve entrapment syndrome is being considered, variations in anatomy are possible etiologic factors. Seventy-nine shoulders from 41 cadavers were examined for anatomic variations and for ganglion cyst formation in the suprascapular notch, superior transverse scapular ligament, and inferior transverse scapular ligament. The morphologic evaluation of the suprascapular notch revealed a "U" shape in 77% and a "V" shape in 23%, with 89% of cadavers having the same notch shape bilaterally. In 23% of shoulders a variation of the superior transverse scapular ligament was demonstrated such as partial and complete ossification and multiple bands including the first report of a trifid superior transverse scapular ligament. An inferior transverse scapular ligament was observed in only 14% of shoulders. One ganglion cyst was identified, for an incidence of 1%. The mass was located in the supraspinatus fossa adjacent to the superior transverse scapular ligament and appeared to compress and alter the course of the suprascapular nerve. When operative treatment is elected for suprascapular nerve entrapment syndrome and an open surgical approach is undertaken, the location and source of disease and morphologic and anatomic variants must be recognized to ensure adequate access and complete decompression of the suprascapular nerve. The classical description of the superior transverse scapular ligament as a completely nonossified single band should be expected, on average, in approximately three fourths of the cases. Partial or complete ossification and anomalous bands of the superior transverse scapular ligament or a ganglion cyst along the course of the suprascapular nerve may be encountered. Although a superior transverse scapular ligament should be anticipated in all shoulders, an inferior transverse scapular ligament will be a much less frequent finding. The role and significance of suprascapular notch morphologic characteristics warrant further investigation.

Aged↗

PubMedDate not supplied

Arthroscopic debridement of the shoulder for osteoarthritis.

Twenty-five patients underwent arthroscopic debridement to treat early glenohumeral osteoarthritis. The group consisted of 19 men and 6 women with an average age of 46 years (range, 27 to 72 years.) The operative procedure consisted of lavage of the glenohumeral joint, debridement of labral tears and chondral lesions, loose body removal, and partial synovectomy and subacromial bursectomy. Follow-up averaged 34 months, with a range of 12 to 63 months. Overall, results were rated as excellent in 2 patients (8%), good in 19 patients (72%), and unsatisfactory in 5 (20%). Two patients had complete relief of pain, 18 patients had only occasional mild pain, and 5 had moderate to severe pain postoperatively. Of the 12 patients with marked preoperative stiffness, 10 (83%) had improvement in range of motion postoperatively. Arthroscopic debridement is a reasonable approach for treating early glenohumeral osteoarthritis that has failed to respond to nonoperative treatment, in which the humeral head and glenoid remain concentric, and where there is still a visible joint space on an axillary radiograph. The procedure is not recommended when there is severe joint incongruity or large osteophytes.

Adult↗

PubMedDate not supplied

Indwelling interscalene catheter anesthesia in the surgical management of stiff shoulder: a report of 100 consecutive cases.

One hundred consecutive stiff shoulders in 93 patients resistant to conservative therapy were treated with surgery and intermittent regional anesthesia via indwelling interscalene catheter. Each patient underwent manipulation and one of several operative treatments to release any additional contracture. The indwelling interscalene catheter remained in place and functioned well for an average of 3 days in 87 shoulders. At an average follow-up of 3.0 years, overall clinical results according to Neer's criteria were excellent in 39 shoulders (39%), satisfactory in 28 (28%), and unsatisfactory in 33 (33%). Patients reported no or mild pain in 83 (83%) of the shoulders in the study. At final follow-up, average gains in motion were 44 degrees of elevation (115 degrees to 159 degrees), 31 degrees of external rotation (22 degrees to 53 degrees), and 5 spine segments of internal rotation (L4 to T11). At final follow-up, 95% of the elevation and 79% of the external rotation achieved intraoperatively were maintained. The best results were obtained in those shoulders with idiopathic stiffness (88% excellent or satisfactory results); the worst results were in the postsurgical shoulders (47% excellent or satisfactory results). There were no catheter-related complications. The use of an indwelling interscalene catheter for postoperative pain control is a safe technique that facilitates early physical therapy in a patient population with a high risk of developing recurrent stiffness.

Adult↗

PubMedDate not supplied

Anterior and posterior musculotendinous anatomy of the supraspinatus.

The objective of this study was to quantitatively describe the supraspinatus musculotendinous architecture. After supraspinatus muscles were harvested from 25 embalmed shoulders, each muscle was divided into an anterior and posterior muscle belly on the basis of muscle fiber insertion. Pennation angles and musculotendinous dimensions were measured, and the physiologic cross-sectional area was calculated for each muscle belly. The physiologic cross-sectional areas of the anterior and posterior bellies were calculated to be 140 +/- 43 mm2 and 62 +/- 25 mm2, respectively, whereas their tendon cross-sectional areas were 26.4 +/- 11.3 mm2 and 31.2 +/- 10.1 mm2, respectively. The average anterior-to-posterior ratios for the muscle physiologic cross-sectional area and the tendon cross-sectional area were 2.45 +/- 0.82 and 0.87 +/- 0.30, respectively. Thus, a larger anterior muscle pulls through a smaller tendon area. These data suggest that physiologically, anterior tendon stress is significantly greater than posterior tendon stress and that rotator cuff tendon repairs should incorporate the anterior tendon whenever possible, inasmuch as it functions as the primary contractile unit.

Aged↗

PubMedDate not supplied

Effects of repetitive subfailure strains on the mechanical behavior of the inferior glenohumeral ligament.

The mechanical response of the inferior glenohumeral ligament to varying subfailure cyclic strains was studied in 33 fresh frozen human cadaver shoulders. The specimens were tested as bone-ligament-bone preparations representing the 3 regions of the inferior glenohumeral ligament (superior band and anterior and posterior axillary pouches) through use of uniaxial tensile cycles. After mechanical preconditioning, each specimen was subjected to 7 test segments, consisting of a baseline strain level L1 (400 cycles) alternating with either 1 (group A, 10 shoulders), 10 (group B, 13 shoulders), or 100 (group C, 10 shoulders) cycles at increasing levels (L2, L3, L4) of subfailure strain. Cycling to higher levels of subfailure strain (L2, L3, L4) produced dramatic declines in the peak load response of the inferior glenohumeral ligament for all specimens. The group of ligaments subjected to 100 cycles of higher subfailure strains demonstrated a significantly greater decrease in load response than the other 2 groups. Ligament elongation occurred with cyclic testing at subfailure strains for all 3 groups, averaging 4.6% +/- 2.0% for group A, 6.5% +/- 2.6% for group B, and 7.1% +/- 3.2% for group C. Recovery of length after an additional time of nearly 1 hour was minimal. The results from this study demonstrate that repetitive loading of the inferior glenohumeral ligament induces laxity in the ligament, as manifested in the peak load response and measured elongations. The mechanical response of the ligament is affected by both the magnitude of the cyclic strain and the frequency of loading at the higher strain levels. The residual length increase was observed in all of the specimens and appeared to be largely unrecoverable. This length increase may result from accumulated microdamage within the ligament substance, caused by the repetitively applied subfailure strains. The clinical relevance of the study is that this mechanism may contribute to the development of acquired glenohumeral instability, which is commonly seen in the shoulders of young athletes who participate in repetitive overhead sports activities.

Adult↗

PubMedDate not supplied

Open revision stabilization surgery for recurrent anterior glenohumeral instability.

Fifty patients (average age, 27 years) who underwent revision anterior stabilization surgery for failed anterior glenohumeral instability procedures were retrospectively reviewed. Failure of the original procedure occurred subsequent to significant trauma in only 17 of 50 shoulders. At revision, 49 shoulders underwent an anteroinferior capsular shift procedure and 23 underwent concurrent repair of a Bankart lesion. One shoulder was treated with a coracoid transfer to reconstruct the anteroinferior glenoid. At an average follow-up of 4.7 years (range, 2 to 10), there were 36 excellent and 3 good results (78%). Eleven shoulders were considered unsatisfactory (22%); 7 of these 11 patients had a diagnosis of voluntary dislocation. All 17 patients who had failed results after significant trauma had excellent results after revision surgery. However, only 22 of the 33 patients (67%) with atraumatic recurrent instability achieved excellent or good results after revision surgery. This difference was statistically significant. No patients had radiographic evidence of osteoarthritis at the most recent follow-up. Range of motion, return to function, and glenohumeral stability can be reliably restored in a high percentage of patients after revision anterior stabilization surgery for glenohumeral instability. However, the results are not as predictable as for primary surgery. Factors associated with poor results of revision repair included an atraumatic cause of failure, voluntary dislocations, and multiple prior stabilization attempts.

Adolescent↗

PubMedDate not supplied

Portal-extension approach for the repair of small and medium rotator cuff tears.

One hundred ten consecutive cases (110 patients) of arthroscopically assisted rotator cuff repair through a limited, portal-extension approach were retrospectively reviewed. The average age of our patients was 58 years (range, 30 to 79). There were 35 women and 75 men. The dominant shoulder was affected in 67 patients (61%). All patients underwent a standard arthroscopic decompression. Acromioclavicular resections were performed in 15% of patients. The anterolateral portal was extended in the direction of Langer's lines to a total length of no more than 3 cm. The torn tendon was accessed through a small deltoid muscle split and repaired with nonabsorbable sutures. At an average follow-up of 35 months (range, 24 to 86), 106 patients (96%) had achieved excellent or satisfactory results. The average American Shoulder and Elbow Surgeons pain score improved from 7 preoperatively to 2 postoperatively. All but four patients were satisfied with the clinical result and reported significant improvement in active elevation and strength and a significant lessening of pain. Late acromioclavicular joint pain contributed to failure in three of the four patients with unsatisfactory results in this series. The results of this study suggest that, in selected patients with small to medium rotator cuff tears, arthroscopically assisted repair through an anterolateral portal-extension approach can produce excellent results.

Adult↗