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Biomedical subjects

William N Levine

Publications and source records attributed to William N Levine.

At least 19 recordsLinked to original sources
PubMed2006

Biomechanical evaluation of subscapularis repair used during shoulder arthroplasty.

Dysfunction of the subscapularis after total shoulder replacement has become concerning and may represent poor tendon healing after surgical repair. The objectives of this study were to evaluate the restoration of subscapularis footprint anatomy and failure strength for subscapularis repair via transosseous tunnels and a second anatomic repair via combined transosseous tunnels and direct tendon-to-tendon repair. Six matched pairs of fresh-frozen human cadaveric shoulders were used, with one shoulder from each pair randomly assigned to a transosseous repair and the contralateral shoulder assigned to a combined transosseous tunnel and direct tendon-to-tendon repair. The repair footprint was digitized. Cyclic loading to the tendon repair was performed followed by a constant ramp displacement to complete failure. The transosseous tunnel repair insertional footprint area (228.6 mm2) was significantly less than that of the native footprint (697.3 mm2), and the footprint centroid moved 9.1 mm medially (P = .0001) and 5.5 mm superiorly (P = .003). The combined repair required a statistically significantly greater number of cycles (P = .028) to reach a 5-mm gap (205.7 +/- 65.1) than did the isolated transosseous tunnel technique (76.4 +/- 34.2). A similar greater number of cycles was observed for the 10-mm gap (P = .01) for combined repair (307.5 +/- 82.4) compared with isolated transosseous repair (166.2 +/- 85.8). This study has shown that transosseous tunnel repair alters subscapularis insertional anatomy, resulting in weaker strength of fixation and less contact area when compared with combined transosseous tunnel and direct tendon-to-tendon repair.

Aged↗
PubMed2006

Shoulder adaptive changes in youth baseball players.

Shoulder adaptive changes in response to overhand throwing have been observed in adults, but the age of onset and progression of these adaptive changes have not been established. Two-hundred ninety-eight youth baseball players (8- to 28-year-olds) were studied to determine whether shoulder range of motion and laxity differences between the dominant and non-dominant shoulders exist between different age groups. The subjects were separated into 3 different age groups of 100 8- to 12-year-olds (Group 1), 100 13- to-14 year-olds (Group 2), and 98 15- to 28-year-olds (Group 3). For dominant shoulder external rotation with the humerus in abduction, all groups were significantly different from each other, with Group 2 having the greatest range and Group 1 having the smallest range (P < .05). When comparing dominant shoulder internal rotation in abduction among different groups, Group 3 and Group 2 motion was significantly less than that for Group 1 (P < .05.) When comparing dominant to non-dominant shoulder motion within each group, a significant increase in dominant shoulder external rotation in abduction was found in all 3 age groups (P < .05). Comparison of the differences in external rotation in abduction between the dominant and non-dominant shoulders demonstrated an increase with increasing age, Group 1 (1.5 +/- 6.8 degrees), Group 2 (9.6 +/- 15.3 degrees), and Group 3 (15.0 +/- 11.2 degrees; P < .05). Comparison of differences in internal rotation in abduction between dominant and non-dominant shoulders demonstrated a decrease with increasing age, Group 1 (4.6 +/- 8.2 degrees), Group 2 (8.4 +/- 14.5 degrees), and Group 3 (15.5 +/- 11.7 degrees; P < .05). For shoulder laxity, Groups 2 and 3 had significantly more inferior shoulder laxity when compared to Group 1. In summary, our results indicate that shoulder range of motion and laxity of youth baseball players are caused by adaptive changes that manifest during adolescence.

Adaptation, Physiological↗
PubMed2006

Arthroscopic distal clavicle resection: a comparison of bursal and direct approaches.

PURPOSE: To test the hypothesis that the direct (superior) approach to arthroscopic distal clavicle resection is as safe and effective as the bursal (subacromial) approach. METHODS: All patients who had an arthroscopic distal clavicle resection in our institution between 1994 and 2002 were reviewed. Patients with a history of acromioclavicular joint (ACJ) instability, previous shoulder surgery, glenohumeral pathology, full-thickness rotator cuff tear, or other significant orthopaedic comorbidity were excluded. Outcome data were collected including the American Shoulder and Elbow Surgeons (ASES) score as well as subjective ratings of pain and instability. RESULTS: Follow-up was completed on 66 shoulders of 60 patients. Twenty-four shoulders had a bursal approach (group I) and 42 had a direct approach (group II). There were 45 men and 15 women with an average age of 46 years (range, 21 to 78 years). Follow-up averaged 6.0 years (range, 2 to 11.5 years). The average ASES score was 90 (range, 53-100) in group I and 94 (range, 55-100) in group II. Four patients (10%) in group II required reoperation: 2 patients required ACJ stabilization at 6 and 9 months postoperatively because of anteroposterior instability, and 2 patients required resection again at 5 years because of recurrent symptoms. CONCLUSIONS: Both the direct and bursal approaches lead to satisfactory outcomes in the majority of patients with ACJ arthrosis. However, the direct approach to the ACJ may damage the superior capsular ligaments, potentially leading to distal clavicle instability. Care should be taken when performing the direct ACJ resection to avoid disrupting the capsular restraints. LEVEL OF EVIDENCE: Level IV therapeutic case series.

Adult↗
PubMed2006

The management of acromioclavicular joint osteoarthrosis: débride, resect, or leave it alone.

The acromioclavicular joint is a small, diarthrodial joint that can cause significant pain. A thorough patient history, careful physical examination, and the judicious use of selective injections are critically important to making an accurate diagnosis. Many radiographic findings are unreliable in determining the reasons for a symptomatic acromioclavicular joint. Recent controversy surrounding this joint has centered on the clinical question: should the acromioclavicular joint be left alone, débrided, or resected? A review of the anatomy, pathophysiology, biomechanics, diagnostic criteria, and treatment options for patients with disorders of the acromioclavicular joint can provide information to answer this question.

Acromioclavicular Joint↗
PubMed2005

Effect of gender and maturity on quadriceps-to-hamstring strength ratio and anterior cruciate ligament laxity.

BACKGROUND: Exercise programs have been introduced to reduce the ACL injury risk in female athletes. The most effective age at which to start these programs is not known. HYPOTHESIS: Age and gender affect ligament laxity and quadriceps-to-hamstring strength ratio. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Fifty-three female and 70 male recreational soccer players, 10 to 18 years of age, were studied with physical examination, KT-1000 arthrometry, and manual maximum quadriceps and hamstring strength using a handheld dynamometer. The subjects were separated into 4 groups to examine maturity-related intergender differences: group G1, premenarchal girls (n = 24); group B1, boys 13 years and younger (n = 38); group G2, girls 2 or more years after menarche (n = 29); and group B2, boys 14 years and older (n = 32). RESULTS: Both knees of 123 soccer players were evaluated. The mean ages for groups G1, B1, G2, and B2 were 11.50 +/- 1.69, 10.63 +/- 1.85, 15.5 +/- 1.43, and 15.59 +/- 1.24 years, respectively, and the mean laxity measurements were 8.84 +/- 2.12, 8.51 +/- 1.61, 8.85 +/- 1.86, and 7.33 +/- 1.27 mm, respectively. Laxity was significantly less for the mature boys (P = .0015) than for the immature boys, mature girls, and immature girls. With increasing maturity, significant increases in both quadriceps and hamstring muscle strength were observed for both boys and girls (P < .05). Boys demonstrated a greater percentage increase in hamstring strength with maturity (179%) compared with girls (27%) (P < .05). Mature girls (2.06) had significantly greater quadriceps-to-hamstring ratio when compared with immature girls (1.74), immature boys (1.58), and mature boys (1.48) (P < .05). CONCLUSION: Female athletes after menarche increase their quadriceps strength greater than their hamstring strength, putting them at risk for anterior cruciate ligament injury. Anterior cruciate ligament-prevention programs based on improving dynamic control of the knee by emphasizing hamstring strengthening should be instituted for girls after menarche.

Adolescent↗
PubMed2005

Tendon-to-bone pressure distributions at a repaired rotator cuff footprint using transosseous suture and suture anchor fixation techniques.

BACKGROUND: Interface contact pressure between the tendon and bone has been shown to influence healing. This study evaluates the interface pressure of the rotator cuff tendon to the greater tuberosity for different rotator cuff repair techniques. HYPOTHESIS: The transosseous tunnel rotator cuff repair technique provides larger pressure distributions over a defined insertion footprint than do suture anchor techniques. STUDY DESIGN: Controlled laboratory study. METHODS: Simulated rotator cuff tears over a 1 x 2-cm infraspinatus insertion footprint were created in 25 bovine shoulders. A transosseous tunnel simple suture technique (n = 8), suture anchor simple technique (n = 9), and suture anchor mattress technique (n = 8) were used for repair. Pressurized contact areas and mean pressures of the repaired tendon against the tuberosity were determined using pressure-sensitive film placed between the tendon and the tuberosity. RESULTS: The mean contact area between the tendon and tuberosity insertion footprint was significantly greater for the transosseous technique (67.7 +/- 5.8 mm(2)) compared with the suture anchor simple (34.1 +/- 9.4 mm(2)) and suture anchor mattress (26.0 +/- 5.3 mm(2)) techniques (P < .05). The mean interface pressure exerted over the footprint by the tendon was also greater for the transosseous technique (0.32 +/- 0.05 MPa) compared with the suture anchor simple (0.26 +/- 0.04 MPa) and suture anchor mattress (0.24 +/- 0.02 MPa) techniques (P < .05). CONCLUSION: The transosseous tunnel rotator cuff repair technique creates significantly more contact and greater overall pressure distribution over a defined footprint when compared with suture anchor techniques. CLINICAL RELEVANCE: Stronger and faster rotator cuff healing may be expected when beneficial pressure distributions exist between the repaired rotator cuff and its insertion footprint. Tendon-to-tuberosity pressure and contact characteristics should be considered in the development of improved open and arthroscopic rotator cuff repair techniques.

Animals↗
PubMed2005

Inhomogeneous mechanical behavior of the human supraspinatus tendon under uniaxial loading.

Disorders of the rotator cuff, particularly tears of the rotator cuff tendons, cause significant shoulder disability. Among numerous factors thought to be responsible for the initiation and progression of supraspinatus tears are those related to the tendon's biomechanical properties. We hypothesized that in supraspinatus tendons subjected to tensile loading a strain gradient (difference) exists between the articular and bursal tendon surfaces, that regional strain differences exist on each of these two tendon surfaces, and that tendon surface strains vary with glenohumeral abduction. To test these hypotheses, the intrinsic inhomogeneous deformational characteristics of the articular and bursal surfaces of eight intact human cadaveric supraspinatus tendons were studied at three glenohumeral abduction angles using a novel multiple strain measuring system which simultaneously recorded surface marker displacements on two opposing soft tissue surfaces. Under applied tensile loads, the articular surface exhibited greater strain at 22 degrees (7.4+/-2.6% vs. 1.3+/-0.7%, p=0.0002) and 63 degrees (6.4+/-1.6% vs. 2.7+/-1.2%, p=0.0001) whereas the bursal surface exhibited greater strain at 90 degrees (7.6+/-2.8% vs. 4.9+/-0.4%, p=0.013). At all abduction angles, insertion strains were higher than those of the mid-tendon and tendon-muscle junction regions. The existence of inhomogeneous surface strains in the intact supraspinatus tendon demonstrates that intratendinous shear occurs within the tendon. The higher strain on the articular side of the tendon, especially at the insertion region, suggests a propensity for tears to initiate in the articular tendinous zone.

Adult↗
PubMed2005

A survey of sports medicine specialists investigating the preferred management of contaminated anterior cruciate ligament grafts.

PURPOSE: To survey leaders in sports medicine who perform anterior cruciate ligament (ACL) reconstructions to determine the preferred management when ACL graft contamination occurs. TYPE OF STUDY: Survey study of expert opinions and experiences on the management of ACL graft contamination. METHODS: We mailed 337 surveys to directors of academic sports medicine programs and graduates from an accredited sports medicine fellowship. The survey questioned the incidence, treatment, and outcome of ACL graft contamination. RESULTS: Twelve surveys were returned to sender; 196 surgeons responded from the remaining 325 surveys (60%). Forty-nine of 196 (25%) surgeons reported at least 1 contamination during their career. Of those 49, 43 surgeons (88%) had 1 contaminated graft, 5 (10%) had 2, and 1 had 4, for a total of 57 reported contaminated grafts. Of the surgeons who reported a contaminated graft, 22 (45%) performed between 40 and 100 ACL reconstructions annually, and 17 (35%) performed more than 100 ACL reconstructions annually. Forty-three of the 57 (75%) contaminated grafts were managed with cleansing of the graft and proceeding with reconstruction. Ten (18%) were managed by harvesting a different graft, and 4 (7%) were substituted with an allograft. No infections in any of the contaminated grafts were reported. Sixty-five of the 147 (43%) surgeons without graft contamination gave hypothetical management responses. Thirty-eight (58%) would cleanse the graft and proceed with the procedure, 22 (34%) would harvest a different graft, and 5 (8%) would use an allograft. CONCLUSIONS: Surgeons who perform a high volume of ACL reconstruction surgery most often choose graft cleansing as the preferred management for intraoperative ACL graft contamination. LEVEL OF EVIDENCE: Level V, expert opinion.

Anterior Cruciate Ligament↗
PubMed2005

Comparison of glenohumeral mechanics following a capsular shift and anterior tightening.

BACKGROUND: Numerous surgical techniques have been developed to treat glenohumeral instability. Anterior tightening procedures have been associated with secondary glenohumeral osteoarthritis, unlike the anterior-inferior capsular shift procedure, which has been widely advocated as a more anatomical repair. The objective of the present study was to quantify glenohumeral joint translations, articular contact, and resultant forces in cadaveric specimens in order to compare the effects of unidirectional anterior tightening with those of the anterior-inferior capsular shift. METHODS: Six normal fresh-frozen cadaveric shoulders were tested on a custom rig with use of a coordinate-measuring machine to obtain kinematic measurements and a six-axis load transducer to measure resultant external joint forces. Shoulders were tested in the scapular plane in three configurations (normal anatomical, anterior tightening, and anterior-inferior capsular shift) and in three humeral rotations (neutral, internal, and external). Glenohumeral articular surface geometry was quantified with use of stereophotogrammetry for kinematic and contact analyses. Resultant joint forces were computed on the basis of digitized coordinates of tendon insertions and origins. RESULTS: Compared with the controls (maximum elevation, 167 degrees 8 degrees ), the anteriorly tightened specimens demonstrated loss of external rotation, significantly restricted maximum elevation (135 degrees 16 degrees , p = 0.002), posterior-inferior humeral head subluxation, and significantly greater posteriorly directed resultant forces at higher elevations (p < 0.05). In contrast, compared with the controls, the specimens that had been treated with the anterior-inferior capsular shift demonstrated a similar maximum elevation (159 degrees +/- 11 degrees , p = 0.8) without any apparent loss of external rotation and with reduced humeral translation. CONCLUSIONS: Anterior tightening adversely affects joint mechanics by decreasing joint stability, limiting both external rotation and arm elevation, and requiring greater posterior joint forces to attain maximum elevation. The anterior-inferior capsular shift improves joint stability while preserving external rotation with no significant loss of maximum elevation.

Adult↗
PubMed2005

Arthroscopic treatment of anterior shoulder instability.

In the late 1980s and early 1990s, several advances in arthroscopic shoulder stabilization procedures were made. However, these early techniques were associated with higher failure rates compared with the traditional open procedures and therefore were not widely disseminated throughout the orthopaedic community. Because of improved understanding in anatomy and pathology in conjunction with dramatic technologic advances, the past decade has demonstrated significant improvement in the arthroscopic management of the unstable shoulder Evolution of arthroscopic techniques over the past 5 years to more closely resemble open procedures has led to clinical outcomes previously seen only with open procedures. Arthroscopy is becoming an attractive treatment option for an increasing number of orthopaedic surgeons.

Arthroscopy↗
PubMed2004

Arthroscopically assisted core decompression of the proximal humerus for avascular necrosis.

Abstract Core decompression has been described as an effective treatment for early stage avascular necrosis of the humeral head. This article describes the technique for arthroscopically assisted core decompression of the humeral head using a transtibial anterior cruciate ligament guide. This technique provides an advantage over the open procedure by avoiding soft-tissue stripping or damaging the biceps tendon or ascending branch of the anterior humeral circumflex artery, as well as providing accurate and safe placement of the core biopsy tract and the ability to address other intra-articular pathology.

Arthroscopy↗
PubMed2004

Thermal capsulorrhaphy.

The initial wave of enthusiasm for thermal capsulorrhaphy has subsided. Long-term clinical data were lacking until D'Alessandro et al's prospective study indicated the results were not as promising as the previously reported short-term studies. Complications including obliteration or attenuation of capsular tissue, axillary nerve injury, and chondrolysis have all been reported in recent years further raising concern about the widespread use of this procedure. The inexact nature of how much "shrinkage" is being performed has led surgeons to further develop surgical technique in capsular plication, shift, or advancement. Although it remains to be seen if these techniques will lead to good clinical outcomes, it appears that they more closely resemble the original operative procedure-anterior capsular shift.

Axilla↗
PubMed2003

Two-part and three-part fractures of the proximal humerus treated with suture fixation.

OBJECTIVE: To evaluate the radiographic and clinical outcomes of patients with displaced proximal humerus fractures (two-part and three-part) treated with nonabsorbable rotator cuff-incorporating sutures. DESIGN: Retrospective. SETTING: University hospital. PATIENTS: There were 27 patients (28 shoulders) with displaced proximal humerus fractures. There were 13 greater tuberosity (GT) and 9 surgical neck (SN) two-part fractures and 6 GT/SN three-part fractures. The average age was 64 years (range 38 to 84 years). The average follow-up was 4.4 years (range 1.0 to 11.5 years). INTERVENTION: All patients were surgically treated solely with heavy polyester nonabsorbable sutures. MAIN OUTCOME MEASUREMENTS: Functional assessment was obtained using the American Shoulder and Elbow Surgeons (ASES) score and Neer's criteria, which grade outcomes as excellent, satisfactory, or unsatisfactory. RESULTS: Overall, there were 22 (78%) excellent, 3 (11%) satisfactory, and 3 (11%) unsatisfactory results, and the average ASES score was 87.1 (range 35.0 to 100.0). All shoulders healed radiographically without evidence of avascular necrosis of the humeral head. Twenty-four shoulders (86%) had anatomic alignment on postoperative radiographs. Of four shoulders with nonanatomic alignment, three had ASES scores of >/=90, with excellent Neer scores. When comparing patients with isolated two-part GT fractures (n = 13) with patients having two-part SN or three-part SN/GT fractures (n = 15), there were no statistically significant differences with respect to range of motion (P > 0.05) and outcome measures (P > 0.05). All patients who had unsatisfactory outcomes were noncompliant with physical therapy, with ASES scores averaging 39.4 (range 35.0 to 43.3). CONCLUSION: Two-part and three-part GT and SN fractures can be treated satisfactorily with heavy nonabsorbable rotator cuff-incorporating sutures, particularly in elderly patients. Hardware-associated complications are obviated. Patients with SN fractures treated with sutures can have outcomes similar to patients with two-part GT fractures. Although the goal is to reconstruct a "one-part" fracture pattern, some residual deformity does not preclude an excellent outcome. A compliant patient is crucial for a successful result.

Adult↗
PubMed2003

Complications after hemiarthroplasty for fractures of the proximal humerus.

Humeral head replacement is frequently used in the treatment of selected fractures of the proximal humerus. This technique is usually successful in terms of pain relief and patient satisfaction. However, complications may occur and can adversely affect outcome. Careful preoperative planning, meticulous surgical technique, and appropriate postoperative rehabilitation are the best methods to promote a successful result. Potential complications and methods to avoid them at initial surgery should be reviewed.

Arthroplasty, Replacement↗