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Clément M L Werner

Publications and source records attributed to Clément M L Werner.

12 recordsLinked to original sources
PubMed2006

Effect of experimental suprascapular nerve block on active glenohumeral translations in vivo.

Static superior shoulder instability is associated with long-standing rotator cuff tears. Factors or mechanisms which can prevent superior migration of the humeral head, and therefore allow preservation or restoration of shoulder function despite nonanatomical cuff repair, are poorly understood. The question has therefore arisen, whether centering of the humeral head was the result of active shoulder muscle function. It was the goal of this experimental investigation to (1) determine the pattern of glenohumeral translations during active shoulder abduction measured by open-magnetic resonance imaging (MRI) techniques, and to (2) determine the influence of experimental paralysis of the infra- and supraspinatus muscles on these translations. In contrast to prior experimental investigations, the humeral head remained always centered in the glenoid fossa during active abduction. No superior migration of the humeral head could be provoked with experimental paralysis of the supra- and/or infraspinatus muscles. The hypothesis that static or dynamic superior humeral head displacement is prevented by active-supra- and/or infraspinatus muscle function must therefore be rejected, for the shoulder with a structurally intact muscle-tendon-bone unit.

Adult↗
PubMed2006

Association of a large lateral extension of the acromion with rotator cuff tears.

BACKGROUND: Factors predisposing to tearing of the rotator cuff are poorly understood. We have observed that the acromion of patients with a rotator cuff tear very often appears large on anteroposterior radiographs or during surgery. The purpose of this study was to quantify the lateral extension of the acromion in patients with a full-thickness rotator cuff tear and in patients with an intact rotator cuff. METHODS: The lateral extension of the acromion was assessed on true anteroposterior radiographs made with the arm in neutral rotation. The distance from the glenoid plane to the lateral border of the acromion was divided by the distance from the glenoid plane to the lateral aspect of the humeral head to calculate the acromion index. This index was determined in a group of 102 patients (average age, 65.0 years) with a proven full-thickness rotator cuff tear, in an age and gender-matched group of forty-seven patients (average age, 63.7 years) with osteoarthritis of the shoulder and an intact rotator cuff, and in an age and gender-matched control group of seventy volunteers (average age, 64.4 years) with an intact rotator cuff as demonstrated by ultrasonography. RESULTS: The average acromion index (and standard deviation) was 0.73 +/- 0.06 in the shoulders with a full-thickness tear, 0.60 +/- 0.08 in those with osteoarthritis and an intact rotator cuff, and 0.64 +/- 0.06 in the asymptomatic, normal shoulders with an intact rotator cuff. The difference between the index in the shoulders with a full-thickness supraspinatus tear and the index in those with an intact rotator cuff was highly significant (p < 0.0001). CONCLUSIONS: A large lateral extension of the acromion appears to be associated with full-thickness tearing of the rotator cuff.

Acromion↗
PubMed2006

Lesser tuberosity osteotomy for total shoulder arthroplasty. Surgical technique.

BACKGROUND: Recent studies have suggested that tenotomy and repair of the subscapularis tendon carried out for anterior approaches to the shoulder can be followed by failure of the tendon repair and by changes resulting in permanent loss of subscapularis function. We hypothesized that release of the subscapularis with use of a superficial osteotomy of the lesser tuberosity followed by repair of the two opposing bone surfaces would lead to consistent bone-to-bone healing, which would be possible to monitor radiographically, and would lead to satisfactory clinical and structural outcomes. METHODS: Thirty-nine shoulders in thirty-six consecutive patients who, at an average age of fifty-seven years, had undergone total shoulder replacement through an anterior approach involving an osteotomy of the lesser tuberosity were evaluated at an average of thirty-nine months. Assessment included a standardized interview and physical examination, scoring according to the system described by Constant and Murley, and imaging with conventional radiography and computed tomography to assess healing of the osteotomy site and changes in the subscapularis. RESULTS: The osteotomized tuberosity fragment healed in an anatomical position in all shoulders, and no cuff tendon ruptures were observed. At the time of follow-up, thirty-three (89%) of thirty-seven shoulders evaluated with a belly-press test had a negative result and twenty-seven (75%) of thirty-six shoulders evaluated with a lift-off test had an unequivocally normal result. Fatty infiltration of the subscapularis muscle increased after the operation (p < 0.0001) and was at least stage two in eleven (32%) of thirty-four shoulders. The fatty infiltration had progressed by one stage in eight (24%) of the thirty-four shoulders, by two stages in five shoulders (15%), and by three stages in two shoulders (6%). CONCLUSIONS: Osteotomy of the lesser tuberosity provides an easy anterior approach for total shoulder replacement and is followed by consistent bone-to-bone healing, which can be monitored, and good subscapularis function. In the presence of documented anatomical healing of the osteotomy site, postoperative fatty infiltration of the subscapularis muscle remains unexplained and needs to be investigated further as it is associated with a poorer clinical outcome.

Adult↗
PubMed2006

Association between rotator cuff abnormalities and reduced acromiohumeral distance.

OBJECTIVE: The purpose of this study was to evaluate the association between rotator cuff abnormalities and reduced acromiohumeral distance. MATERIALS AND METHODS: Acromiohumeral distance was measured on conventional radiographs and on MR images. Three age- and sex-matched patient groups each including 21 patients were stratified according to acromiohumeral distance on conventional radiographs (group 1, 10 mm). Acromiohumeral distance was related to the presence, location, and size of a rotator cuff tear and the degree of fatty degeneration of the muscle assessed on MR arthrography. The relative influence on acromiohumeral distance of the various MR arthrographic findings was assessed. Spearman's rank correlation and stepwise regression were used for statistical analysis. RESULTS: In group 1 (acromiohumeral distance <or= 7 mm) full-thickness supraspinatus tendon tears were present in 90% (19/21) of the patients, infraspinatus tendon tears in 67% (14/21) of the patients, and subscapularis tendon tears in 43% (9/21) of the patients. The size of rotator cuff tendon tears and the degree of fatty degeneration in all rotator cuff muscles showed a significant negative correlation with acromiohumeral distance (p < 0.05). After stepwise regression, a significant relative influence on acromiohumeral distance remained for size of rotator cuff tear (p < 0.0001) and for degree of fatty degeneration of the infraspinatus muscle (p = 0.013). CONCLUSION: Tendon tears and fatty muscle degeneration in the rotator cuff correlate with reduced acromiohumeral distance. Size of rotator cuff tear and degree of fatty degeneration of the infraspinatus muscle have the most pronounced influence on acromiohumeral distance.

Acromion↗
PubMed2005

Two-stage reconstruction with free vascularized soft tissue transfer and conventional bone graft for infected nonunions of the tibia: 6 patients followed for 1.5 to 5 years.

BACKGROUND: Vascularized soft tissue transfer may give better results of treatment of infected nonunions of the tibia. METHODS: 6 patients with infected nonunion of the tibia and combined soft tissue (70-170 cm(2)) and bony (5-8 cm) defects underwent staged reconstruction. Initial surgery consisted of soft tissue and bone debridement, external fixation, filling of the bony defect with a gentamicin-impregnated cement spacer, and reconstruction of the soft tissue with a free microsurgical muscle flap and skin graft. Second-stage surgery consisted of removal of the cement spacer and osseous reconstruction with nonvascularized bone graft. RESULTS: All patients except 1 achieved full weight-bearing and radiographic consolidation after 7-10 months. This patient required repeated bone grafting and internal plate fixation to heal. There were no cases of recurrence of infection at the latest follow-up, after a mean of 3 (1.5-5) years. INTERPRETATION: Staged reconstruction with free vascularized soft tissue transfer and conventional bone grafting within a cement-induced membrane is a low-risk surgical strategy resulting in a high rate of bone healing.

Adult↗
PubMed2005

Radiographic and computed tomography analysis of cemented pegged polyethylene glenoid components in total shoulder replacement.

BACKGROUND: Glenoid loosening continues to be the primary reason for failure of total shoulder arthroplasty. The purpose of this study was to evaluate, with use of a sensitive and reproducible imaging method, the radiographic and clinical results of total shoulder replacement with a pegged, cemented polyethylene glenoid implant. METHODS: Forty-three patients (forty-seven shoulders) underwent a total shoulder replacement with a cemented polyethylene glenoid component with four threaded pegs. The patients were examined clinically, with fluoroscopically guided radiographs, and with computed tomography at an average of forty months. In addition to conventional scoring of radiographic lucency, an 18-point scoring system was used to quantify cement-peg lucencies in six zones of the back surface of the glenoid component as seen on computed tomography scans. RESULTS: On the average, the absolute Constant score improved from 39 points preoperatively to 70 points at the time of follow-up (p = 0.0001) and the pain score improved from 5 to 13 points (p = 0.001). The mean active anterior elevation improved by 34 degrees (p = 0.001) and the mean abduction, by 46 degrees (p = 0.006). Two patients had symptomatic glenoid loosening requiring revision. Twenty-one of the forty-seven shoulders had radiographic lucency around the glenoid pegs, and nine had progression of the lucency by at least two grades. Computed tomography detected lucencies, primarily at the bone-cement interface, in thirty-six shoulders. The scores for the lucencies seen on the computed tomography scans were associated with the radiographic lucency scores (p < 0.001), pain scores (p = 0.04), and abduction strength (p = 0.02). Computed tomography was more sensitive than radiography with regard to identifying the number of pegs associated with lucency and the size of the lucencies. The overall reproducibility of the scoring based on the computed tomography was higher than that of the radiographic scoring. CONCLUSIONS: Computed tomography provided a more sensitive and reproducible tool for the assessment of loosening of pegged glenoid components than did fluoroscopically guided conventional radiography. Further improvement in implant design and fixation technique appears to be necessary for long-term success of cemented glenoid components.

Adult↗
PubMed2005

Subscapularis muscle function and structure after total shoulder replacement with lesser tuberosity osteotomy and repair.

BACKGROUND: Recent studies have suggested that tenotomy and repair of the subscapularis tendon carried out for anterior approaches to the shoulder can be followed by failure of the tendon repair and by changes resulting in permanent loss of subscapularis function. We hypothesized that release of the subscapularis with use of a superficial osteotomy of the lesser tuberosity followed by repair of the two opposing bone surfaces would lead to consistent bone-to-bone healing, which would be possible to monitor radiographically, and would lead to satisfactory clinical and structural outcomes. METHODS: Thirty-nine shoulders in thirty-six consecutive patients who, at an average age of fifty-seven years, had undergone total shoulder replacement through an anterior approach involving an osteotomy of the lesser tuberosity were evaluated at an average of thirty-nine months. Assessment included a standardized interview and physical examination, scoring according to the system described by Constant and Murley, and imaging with conventional radiography and computed tomography to assess healing of the osteotomy site and changes in the subscapularis. RESULTS: The osteotomized tuberosity fragment healed in an anatomical position in all shoulders, and no cuff tendon ruptures were observed. At the time of follow-up, thirty-three (89%) of thirty-seven shoulders evaluated with a belly-press test had a negative result and twenty-seven (75%) of thirty-six shoulders evaluated with a lift-off test had an unequivocally normal result. Fatty infiltration of the subscapularis muscle increased after the operation (p < 0.0001) and was at least stage two in eleven (32%) of thirty-four shoulders. The fatty infiltration had progressed by one stage in eight (24%) of the thirty-four shoulders, by two stages in five shoulders (15%), and by three stages in two shoulders (6%). CONCLUSIONS: Osteotomy of the lesser tuberosity provides an easy anterior approach for total shoulder replacement and is followed by consistent bone-to-bone healing, which can be monitored, and good subscapularis function. In the presence of documented anatomical healing of the osteotomy site, postoperative fatty infiltration of the subscapularis muscle remains unexplained and needs to be investigated further as it is associated with a poorer clinical outcome.

Adult↗
PubMed2004

The effect of capsular tightening on humeral head translations.

UNLABELLED: Idiopathic or surgical tightening of the glenohumeral joint capsule may cause displacement of the humeral head relative to the glenoid fossa and favor the development of instability and/or osteoarthritis. In the present investigation the relative position of the humerus to the glenoid fossa was determined at the end of the ranges of eight different passive movements before and after selective capsular plication in eight cadaveric shoulders to study the effects of selective capsular plications on the kinematics of the shoulder. While the capsule was in its unaltered state, translation of the humeral head was 3.8 mm superiorly in abduction, 7.3 mm antero-superiorly in flexion. In internal rotation in 0 degrees, 45 degrees and 90 degrees of abduction the head moved 6.1, 8.0 and 12.0 mm antero-inferiorly. In external rotation at 0 degrees of abduction the translation was 0.9 mm antero-inferiorly, at 45 degrees and 90 degrees of abduction it was 4.3 and 5.6 mm postero-inferiorly, respectively. Plications of the anterior part of the capsule reproducibly and significantly either increased or decreased translations during flexion (up to 5.9 mm anteriorly and up to 3.8 mm inferiorly), external rotation (up to 2.9 mm posteriorly and 1 mm inferiorly) and internal rotation (from 5.5 mm posteriorly to 2 mm anteriorly and up to 2.2 mm superiorly). Posterior plications had only little effect on translations (mainly a decrease of anterior translation during flexion of 2.8 mm). CLINICAL RELEVANCE: The 'obligate' glenohumeral translations which occur towards the end of passive shoulder movements are altered in a reproducible fashion by tightening specific parts of the glenohumeral joint capsule, as often carried out in treatment of shoulder instability. These alterations of the kinematics of the glenohumeral joint may be relevant for the development of static subluxation and osteoarthitis as seen after too tight plication in the treatment of instability [Int. Orthop. (SICOT) 67-B (1985) 709; J. Bone Joint Surg. Am. 72 (1990) 1193; J. Bone Joint Surg. Am. 66-A (1984) 169; J. Bone Joint Surg. Am. 65 (1983) 456].

Humans↗
PubMedDate not supplied

Biomechanical relevance of glenoid component positioning in the reverse Delta III total shoulder prosthesis.

The presence of a notch at the inferior part of the scapular neck is a common radiographic finding in patients treated with a reverse Delta III shoulder prosthesis. It is thought that this notch is a result of mechanical contact between the polyethylene cup of the humeral implant and the inferior glenoid pole during adduction of the arm. This in vitro study assessed the effect of glenoid component positioning on glenohumeral range of motion in 8 shoulder specimens. Four different positions of the glenosphere were tested: glenosphere centered on the glenoid, leaving the inferior glenoid rim uncovered (configuration A); glenosphere flush with the inferior glenoid rim (configuration B); glenosphere extending beyond the inferior glenoid rim (configuration C); and glenosphere tilted downward 15 degrees (configuration D). The respective mean adduction and abduction angles in the scapular plane were -25 degrees and 67 degrees for configuration A, -14 degrees and 68 degrees for configuration B, -1 degrees and 81 degrees for configuration C, and -9 degrees and 75 degrees for configuration D. Placing the glenosphere distally (test configuration C) significantly improved adduction and abduction angles compared with all other test configurations (P < .001).

Biomechanical Phenomena↗
PubMedDate not supplied

Subacromial pressures in vivo and effects of selective experimental suprascapular nerve block.

Subacromial impingement has been related to increased subacromial pressures. High subacromial pressures may, therefore, have a negative effect on tendon healing after rotator cuff repair, but avoidance of high pressures during healing is only possible if pressures in different positions of the arm are known. The purpose of this study was to determine the subacromial pressures for different positions of active shoulder movement and to determine the effects of supraspinatus and infraspinatus failure on subacromial pressures, as it is currently held that rotator cuff weakness might increase subacromial pressures. Subacromial pressures were statistically significantly altered by arm position (P = .001). There was an increase in pressure from 17.5 mm Hg at rest up to more than 60 mm Hg during abduction and flexion. Subacromial pressure decreased in external rotation and increased in internal rotation. Generally, patients with strong external rotation (arm at the side) had lower subacromial pressures. Conversely, paralysis of the supraspinatus or infraspinatus muscles had no statistically significant effect on subacromial pressures at rest or during active movements of the shoulder. High subacromial pressures can be prevented by avoiding active abduction, flexion, and internal rotation of the arm. External rotation does not need to be limited to reduce subacromial pressure.

Humans↗
PubMedDate not supplied

The biomechanical role of the subscapularis in latissimus dorsi transfer for the treatment of irreparable rotator cuff tears.

Inferior functional results of latissimus tendon transfer for the treatment of irreparable rotator cuff tears have been reported in the presence of a subscapularis tendon tear. A biomechanical or experimental explanation for the necessity of an intact subscapularis is unavailable. It was, therefore, the purpose of this investigation to study the biomechanical role of the subscapularis in the treatment of a posterosuperior rotator cuff tear with latissimus dorsi transfer. A biomechanical cadaveric model was developed to reproduce glenohumeral motion patterns created by loading of the transferred latissimus dorsi tendon with and without simultaneous action of the subscapularis muscle. Significant differences could be demonstrated not only for translation but also for rotation of the humeral head depending on subscapularis action. In the neutral and in the abducted/externally rotated position of the arm, anterior translation and dislocation of the joint were encountered without subscapularis action. Our results provide evidence that motion patterns of the humeral head are significantly altered in the absence of the stabilizing effect of the subscapularis muscle. The inferior functional results of latissimus dorsi transfer in the presence of subscapularis dysfunction are explained by the loss of centering of the humeral head upon abduction and elevation if subscapularis function is deficient.

Aged↗