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Biomedical subjects

Louis U Bigliani

Publications and source records attributed to Louis U Bigliani.

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

The inferior glenohumeral ligament: a correlative investigation.

The inferior glenohumeral ligament (IGHL) was investigated by correlating the biomechanical properties, biochemical composition, and histologic morphology of its 3 anatomic regions (superior band, anterior axillary pouch, and posterior axillary pouch) in 8 human cadaveric shoulders. The overall biochemical composition of the IGHL appeared similar to other ligaments, with average water content of 80.9 +/- 2.5%, collagen content of 80.0 +/- 9.2%, and crosslinks of 0.715 +/- 0.13 mol/mol collagen. The proteoglycan content was highest in the superior band (2.73 +/- 0.7 mg/g dry weight) and may, in part, explain its viscoelastic behavior. Histologic analysis demonstrated longitudinally organized fiber bundles that were more uniform in the mid-substance but more interwoven and less uniformly oriented near the insertion sites. The superior band had the most pronounced fiber bundle interweaving, while crimping was more evident in the anterior axillary pouch. Elastin was identified in each of the regions. Tensile testing demonstrated a trend toward higher ultimate tensile stress (16.9 +/- 7.9 MPa) and tensile modulus (130.3 +/- 47.9 MPa) in the superior band compared to the axillary pouch. The mean ultimate tensile strain of the IGHL was 16.8 +/- 4.6%. These complex IGHL properties may help to explain its unique functions in stabilizing the shoulder in different arm positions and at different rates of loading, including the failure patterns seen clinically, as in Bankart lesions (insertion site) versus capsular stretching (ligament substance).

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

Stromal cell-derived factor 1 (SDF-1, CXCL12) is increased in subacromial bursitis and downregulated by steroid and nonsteroidal anti-inflammatory agents.

Several studies have demonstrated that inflammation in the subacromial bursa is an important component in the pathogenesis of impingement syndrome. We have demonstrated in a previous study that many inflammatory cytokines, including stromal cell-derived factor 1 (SDF-1, CXCL12), are increased in the subacromial bursa [Blaine et al. 2005. J Shoulder Elbow Surg 14(Suppl 1):84S-89S]. SDF-1 is a potent chemotactic and angiogenic factor that stimulates recruitment of inflammatory cells. In the current study, we proposed that the resident cells in subacromial bursal tissue produce SDF-1, which can play a role in the inflammatory reponse of bursal tissue, and that this chemokine can be regulated by steroid (dexamethasone) and nonsteroidal anti-inflammatory medications (NSAIDs). Twenty-two subacromial bursa tissues (18 bursitis and 4 normal bursa) were obtained intraoperatively from patients during shoulder surgery and analyzed using the cDNA Array technique in accordance with an IRB approved protocol. cDNA array results were confirmed with real-time reverse transcription-polymerase chain reaction (RT-PCR). Bursal cells (from 4 normal bursa, 3 bursitis) and two normal bone marrow with whole tissue explants were cultured for one passage. Cell culture supernatants were collected and SDF-1 protein was detected with enzyme-linked immunosorbent assay (ELISA). Cultured bursal cells were treated with a COX-2 inhibitor and dexamethasone, and cells was harvested at 1-day and 4-day intervals. SDF-1 expression was evaluated by real-time RT-PCR and ELISA. cDNA Array analysis demonstrated that the gene expression of SDF-1 was increased in patients with subacromial bursitis compared to controls (p < 0.05). Real-time RT-PCR also revealed that the mRNA expression of SDF-1 in bursitis tissue is increased 10-fold over control tissue. While the normal bursal cells produced negligible amounts of SDF-1 protein, cultured cells derived from bursitis lesion released as much SDF-1 protein (235 pg/100,000 cells) as normal bone marrow stromal cells (283 pg/100,000 cells) as measured by ELISA. The addition of a COX-2 inhibitor and dexamethasone to bursitis cell lines led to decreased SDF-1 expression levels compared to untreated bursitis cell lines. These studies demonstrate that there is a significant elevation of SDF-1 expression in the subacromial bursa of patients with rotator cuff disease. Furthermore, this chemokine can be downregulated by COX-2 inhibitors and steroids. These results provide biologic evidence for the use of steroid and NSAIDs in the treatment of subacromial bursitis. In the future, targeted inhibition of molecules such as SDF-1 in the subacromial bursa may present a therapeutic strategy that may avoid the side effects of these other (steroid and NSAID) medications.

Adult↗
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

Shoulder impingement revisited: advanced concepts of pathomechanics and treatment.

Subacromial impingement is a common disorder of the shoulder that is still poorly understood. Knowledge of the pathogenesis of this condition has expanded greatly since it was described by Neer 40 years ago. Research has shown that multiple factors contribute to the development of rotator cuff disease. New investigations are exploring this disorder with input from several scientific disciplines. It is essential that orthopaedic surgeons treating patients with subacromial impingement understand the underlying mechanisms, the new research, and the current trends in management of this disease.

Biomechanical Phenomena↗
PubMed2005

Tendon-bone interface motion in transosseous suture and suture anchor rotator cuff repair techniques.

BACKGROUND: Although many studies involving rotator cuff repair fixation have focused on ultimate fixation strength and ability to restore the tendon's native footprint, no studies have characterized the stability of the repair with regard to motion between the tendon and repair site footprint. HYPOTHESIS: Suture anchor fixation for rotator cuff repair has greater interface motion between tendon and bone than does transosseous suture fixation. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve fresh-frozen human cadaveric shoulders were tested in a custom device to position the shoulder in internal and external rotations with simulated supraspinatus muscle loading. Tendon motion relative to the insertional footprint on the greater tuberosity was determined optically using a digital camera rigidly connected to the humerus, with the humerus positioned at 60 degrees of internal rotation and 60 degrees of external rotation. Testing was performed for the intact tendon, a complete supraspinatus tear, a suture anchor repair, and a transosseous tunnel repair. RESULTS: Difference in tendon-bone interface motion when compared with the intact tendon was 7.14 +/- 3.72 mm for the torn rotator cuff condition, 2.35 +/- 1.26 mm for the suture anchor repair, and 0.02 +/- 1.18 mm for the transosseous suture repair. The transosseous suture repair demonstrated significantly less motion when compared with the torn rotator cuff and suture anchor repair conditions (P < .05). CONCLUSION: Transosseous suture repair compared with suture anchor repair demonstrated superior tendon fixation with reduced motion at the tendon-to-tuberosity interface. CLINICAL RELEVANCE: Development of new fixation techniques for arthroscopic and open rotator cuff repairs should attempt to minimize interface motion of the tendon relative to the tuberosity.

Arthroscopy↗
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

mu-Calpain regulates receptor activator of NF-kappaB ligand (RANKL)-supported osteoclastogenesis via NF-kappaB activation in RAW 264.7 cells.

To clarify the role of calpain in the receptor activator of NF-kappaB ligand (RANKL)-supported osteoclastogenesis, RANKL-induced calpain activation was examined by using murine RAW 264.7 cells and bone marrow-derived monocyte/macrophage progenitors. We found that calpain activity increased in response to RANKL in both cell types based on alpha-spectrinolysis and that mu-calpain, rather than m-calpain, was activated during RANKL-supported osteoclastogenesis in RAW 264.7 cells. Overexpression of mu-calpain clearly augmented RANKL-supported osteoclastogenesis in RAW 264.7 cells, thereby implicating its pivotal role in this process. Cell-permeable calpain inhibitors, including calpastatin and calpeptin, were sufficient to suppress RANKL-supported osteoclastogenesis based on decreased expression of the osteoclastogenic marker, matrix metalloproteinase 9, and the generation of tartrate-resistant acid phosphatase-positive multinucleated cells in both cell types. Calpain inhibitors suppressed NF-kappaB activation via inhibition of the cleavage of inhibitor of NF-kappaB(IkappaBalpha)in RAW 264.7 cells. Taken together, our findings suggest that mu-calpain is essential to the regulation of RANKL-supported osteoclastogenesis via NF-kappaB activation.

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

Proinflammatory cytokines and metalloproteases are expressed in the subacromial bursa in patients with rotator cuff disease.

PURPOSE: The pathophysiology of subacromial impingement syndrome is poorly understood. We investigated the expression of inflammatory cytokines, metalloproteases, and the cyclooxygenases in the subacromial bursa in control patients and in patients with rotator cuff tear. TYPE OF STUDY: Basic science evaluation. METHODS: Eighteen patients undergoing shoulder surgery had a subacromial bursa biopsy examination. Patients were divided into 2 groups. Group I (study group) had 10 patients with a full-thickness rotator cuff tear (RCT). Group II (control group) had 8 patients. Seven of 8 underwent shoulder arthroscopy with anterior capsular reconstruction for instability; 1 of 8 underwent open reduction internal fixation for acute proximal humerus fracture. None of the patients in group II had any history of symptoms or signs consistent with subacromial impingement. H&E and immunohistochemical antibody (MMP-1, MMP-9, IL-1, IL-6, TNF-alpha, COX-1, and COX-2) stained specimens were examined by 2 blinded observers using a histologic scale (grade 0 = no staining to grade 4 = intense staining). RESULTS: Histologic evidence of inflammation was present in all patients with RCT (group I). No or mild inflammation was noted in group II. The average staining grade for inflammatory cytokines (IL-1, IL-6, TNF-alpha) and proteinases (MMP-1 and MMP-9) was significantly more pronounced in the RCT group (P < .001). Cyclooxygenase enzymes (COX-1 and COX-2) were also increased in group II (P < .001). CONCLUSIONS: A high level of expression of inflammatory cytokines, proteinases, and cyclooxygenase enzymes, known to produce a catabolic environment, is present in the subacromial bursa of patients with rotator cuff tear. CLINICAL RELEVANCE: These findings support the role of nonsteroidal anti-inflammatory drugs and corticosteroids in RCT treatment, and emphasize the importance of subacromial bursectomy to reduce inflammation in RCT surgery.

Adrenal Cortex Hormones↗
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↗
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↗
PubMed2004

Arthroscopic acromioplasty: history, rationale, and technique.

Subacromial impingement or supraspinatus syndrome has been known to exist in some form since the early 1900s. Several early studies have discussed subacromial impingement or supraspinatus syndrome. Arthroscopic acromioplasty has evolved as a useful surgical treatment. Pertinent physical examination and radiographic evaluation findings must be identified. In order for the surgery to be successful, it is important to understand the rationale for treatment of impingement syndrome and the technical aspects of arthroscopic acromioplasty.

Acromion↗