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F A Matsen

Publications and source records attributed to F A Matsen.

At least 19 recordsLinked to original sources
PubMed1996

Effect of a chondral-labral defect on glenoid concavity and glenohumeral stability. A cadaveric model.

One of the primary stabilizing mechanisms of the glenohumeral joint is concavity-compression, the maintenance of the humeral head in the concave glenoid fossa by the compressive force generated by the surrounding muscles. This mechanism is active in all glenohumeral positions but it is particularly important in the functional mid-range, in which the capsule and ligaments are slack. The effectiveness of concavity-compression in the stabilization of a joint can be characterized in terms of the ratio between the maximum dislocating force that can be stabilized in a given direction and the load compressing the head into the glenoid (the stability ratio). Glenoid concavity can be described by the lateral humeral displacement during translation across the glenoid. The purpose of the present investigation was to characterize the concavity and stability ratios of normal cadaveric glenoids, to measure the effect of an anteroinferior chondral-labral defect on these parameters, and to measure the effectiveness of a simulated operative reconstruction on the restoration of glenoid concavity and the stability ratio. The chondral-labral defect created in this study reduced the height of the glenoid by approximately 80 per cent and the stability ratio by approximately 65 per cent for translation in the direction of the defect. Reconstruction of the anteroinferior aspect of the glenoid concavity with use of an autogenous biceps-tendon graft restored normal values for these variables.

Aged↗
PubMed1995

A model for the study of wounds in normal elderly adults and patients with peripheral vascular disease or diabetes mellitus.

The purpose of the study was to test the hypothesis that significant delays in cutaneous wound healing could be demonstrated using standard wounds and high quality histological methods in patients with severe peripheral vascular disease (PVD) and/or diabetes mellitus (DM) compared to healthy elderly controls. Additionally, we proposed that standard wounds on the arms of elderly controls would heal more rapidly than comparable wounds on the legs. In order to test these hypotheses we developed and characterized a partial thickness wound model which could be used safely in human subjects. The study population consisted of 25 elderly normal volunteers, 17 patients with PVD, and 24 patients with DM. Standard wounds were created using a Simplate II bleeding-time device. A total of 309 wounds ranging in age from 1 to 25 days were determined to be suitable for analysis. A global index of wound maturity was developed based on selected epidermal and dermal events of repair which could be scored histologically. The superficial component (within 0.1 mm of the epidermis) and deep components of dermal wounds were analyzed separately. Simultaneously created arm and leg wounds were studied in 15 of the elderly controls. Transcutaneous partial pressure of oxygen (TcPO2) measurements were used to estimate the severity of cutaneous ischemia. Data analysis revealed that the most striking differences observed were in dermal events of repair. Control wounds were more mature than dermal wounds from patients with PVD (P < 0.05). A significant reduction in the number of neutrophils and macrophages (P < 0.05) was demonstrated in 7-day-old wounds of patients with PVD compared to controls. Patients with DM showed a similar trend of reduced wound maturity but it did not reach statistical significance. Wounds created in skin with TcPO2 > 20 were more mature than wounds with TcPO2 < or = 20 (P < 0.05) and arm wounds were more mature than leg wounds (P < 0.01). The most significant difference noted in this wound model was that the superficial compartment of dermal wounds was significantly more mature than the deep compartment (P < 0.001). Good agreement was observed between two independent scorers of wound histology and no complications were noted in either patients or controls when using this human wound model. We conclude that the model described allows evaluation of both epidermal and dermal events of repair with relative safety even in patients with PVD and DM.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1995

The effect of articular conformity and the size of the humeral head component on laxity and motion after glenohumeral arthroplasty. A study in cadavera.

We used a cadaveric model to examine the mechanical effects of changes in the conformity of the articular surfaces and the size of the humeral head component in glenohumeral arthroplasty. The experimental system permitted a manual clinical examination of the glenohumeral joint while sensors monitored the humeroscapular position and orientation as well as the forces and torques applied by the examiner. Four preparations were compared: an anatomical humeroscapular preparation and three glenohumeral arthroplasty preparations (one with anatomically sized components and a radius of curvature of the glenoid that was four millimeters larger than that of the humeral head, one with anatomically sized components and a radius of curvature of the glenoid that was equal to that of the humeral head, and one with a non-anatomical, large humeral head component and a radius of curvature of the glenoid that was equal to that of the humeral head). All motions, including flexion, external and internal rotation, and maximum elevation, were diminished with use of the non-anatomical, large humeral head component. Laxity of the joint on drawer and sulcus tests was not affected by the conformity of the articular surfaces but was decreased significantly by implantation of the large humeral head component. The kinematics of the glenohumeral joint were not markedly altered by reduction of the uniformity between the articular surfaces of the prosthetic components. In all preparations, obligate displacement of the humeral head associated with a passive range of motion occurred at smaller angles with the large humeral head component.

Aged↗
PubMed1995

Association of sonographically detected subacromial/subdeltoid bursal effusion and intraarticular fluid with rotator cuff tear.

OBJECTIVE: Although an association between sonographically detected joint fluid and rotator cuff disease has been reported, the significance of sonographically detected subacromial/subdeltoid bursal effusion has not been studied. We examined a group of patients who had shoulder sonography and surgery to determine the association between bursal and joint effusion and surgically proved tears of the rotator cuff. MATERIALS AND METHODS: We retrospectively reviewed the preoperative shoulder sonography reports of 163 patients for the presence of fluid within the subacromial/subdeltoid bursa or glenohumeral joint. Surgical reports were obtained to determine the status of the rotator cuff. The sonographic reports of 232 asymptomatic shoulders were also reviewed to determine the prevalence of fluid within the subacromial/subdeltoid bursa or the glenohumeral joint. RESULTS: Sixty-seven (41%) of the 163 patients had a joint effusion, bursal fluid, or both. Joint effusion alone was seen in 35 patients. Fourteen of these had a normal rotator cuff at surgery, and 21 had a rotator cuff tear (sensitivity, 22%; specificity, 79%; positive predictive value, 60%). Bursal fluid alone was seen in 10 patients, seven of whom had a rotator cuff tear (sensitivity, 7%; specificity, 96%; positive predictive value, 70%). In 22 patients, fluid was seen in both the bursa and the joint; 21 had surgically proved rotator cuff tears (sensitivity, 22%; specificity, 99%; positive predictive value, 95%). Of the 232 asymptomatic shoulders, 16 (6.9%) had isolated joint effusions, eight (3.4%) had isolated bursal effusions, and four (1.7%) had both joint and bursal effusions. CONCLUSION: The sonographic finding of intraarticular fluid alone (without bursal fluid) has both a low sensitivity and a low specificity for the diagnosis of rotator cuff tears. However, the finding of fluid in the subacromial/subdeltoid bursa, especially when combined with a joint effusion, is highly specific and has a high positive predictive value for associated rotator cuff tears. Sonographically detected fluid in both the joint and the bursa is an uncommon finding in asymptomatic shoulders. The sonographic observation of fluid in the subacromial bursa, either isolated or combined with a joint effusion, should prompt a careful evaluation of the supraspinatus tendon for tear.

Acromion↗
PubMed1995

Rotator cuff.

Explore the source record for details and available documents.

Adult↗
PubMed1993

Prosthetic replacement of the shoulder for the treatment of defects in the rotator cuff and the surface of the glenohumeral joint.

We operatively treated, between 1978 and 1987, twenty-one shoulders in nineteen patients, fifty-four to eighty-four years old, who had disabling pain attributable to a massive tear of the rotator cuff, accompanied by loss of the surface of the glenohumeral joint. These patients were not candidates for total shoulder replacement because of the massive deficiency in the cuff and the fixed upward displacement of the humeral head. A prerequisite for hemiarthroplasty was a functionally intact coracoacromial arch to provide superior secondary stability for the prosthesis. One important aspect of the operative technique was the selection of a sufficiently small prosthesis so that excessive tightness of the posterior aspect of the capsule could be avoided. Eighteen shoulders in sixteen patients were available for follow-up, which ranged from twenty-five to 122 months. Pain decreased from marked or disabling in fourteen shoulders preoperatively to none or slight in ten and to pain only after unusual activity in four. Active forward elevation improved from an average of 66 degrees preoperatively to an average of 109 degrees postoperatively. One patient, who had had an excellent result, fell and sustained an acromial fracture, so the functional result changed to poor. Three patients had persistent, substantial pain in the shoulder that led to a revision. Neither infection nor prosthetic loosening developed in any shoulder.

Aged↗
PubMed1993

Robotic assistance in orthopaedic surgery. A proof of principle using distal femoral arthroplasty.

The term "robot" refers to a precision mechanical device that is accurately controlled by a computer using intelligent software. The term "robotic assistance" refers to the use of such a device to aid a surgeon in the optimal conduct of a procedure, particularly one requiring specified geometrical relationships. The authors have been exploring the application of robotic assistance in situations in which accuracy and precision are required in orthopaedic surgery. The initial application concerned the planning, positioning, and orientation cuts and holes of the bone required for the femoral component of a total knee arthroplasty. A three-dimensional digitizing template allowed the surgeon to specify the desired position and orientation of the component's articular surfaces in relation to the distal femur. The robotic system used this spatial relationship, along with its knowledge of the geometry of the component selected by the surgeon, to plan the precise location of the required bone cuts and holes. Finally, the robotic assistant sequentially positioned saw and drill guides with respect to the distal femur so that the surgeon made these cuts and holes in the locations necessary for optimal component fit, position, and orientation. The robotic assistant functioned easily in the operating room environment; increased the accuracy; and decreased the time, equipment, and personnel required for the conduct of the geometrical part of this surgical procedure.

Hip Prosthesis↗
PubMed1992

The role of the rotator interval capsule in passive motion and stability of the shoulder.

The purpose of this study was to characterize the role of the capsule in the interval between the supraspinatus and subscapularis tendons with respect to glenohumeral motion, translation, and stability. We used a six-degrees-of-freedom position-sensor and a six-degrees-of-freedom force and torque-transducer to determine the glenohumoral rotations and translations that resulted from applied loads in eight cadaver shoulders. The range of motion of each specimen was measured with the capsule in the rotator interval in a normal state, after the capsule had been sectioned, and after it had been imbricated. Operative alteration of this capsular interval was found to affect flexion, extension, external rotation, and adduction of the humerus with respect to the scapula. Modification of this portion of the capsule also affected obligate anterior translation of the humeral head on the glenoid during flexion. Limitation of motion and obligate translation were increased by operative imbrication and diminished by sectioning of the rotator interval capsule. Passive stability of the glenohumeral joint was evaluated with the use of anterior, posterior, and inferior stress tests. Instability and occasional frank dislocation of the glenohumeral joint occurred inferiorly and posteriorly after section of the rotator interval capsule. Imbrication of this part of the capsule increased the resistance to inferior and posterior translation.

Aged↗
PubMed1991

Surgical management of complex irreparable rotator cuff deficiency.

The authors surgically treated 23 shoulders in 23 patients with disabling pain associated with irreparable tears of the musculotendinous cuff. In a total of 12 shoulders with preserved passive motion, normal deltoid function, loss of glenohumeral joint surfaces, and sculpturing of the coracoacromial arch, a standard or oversized Neer II humeral prosthesis without glenoid replacement was selected. A total of 11 shoulders that failed to meet these prerequisites or demanded heavy use after operation underwent arthrodesis. Twenty-two patients (12 from the hemiarthroplasty group and 10 from the arthrodesis group) were available for evaluation at an average follow-up period of 37.5 months. Comfort level and overall function were improved in both groups. Active forward elevation improved an average of 44 degrees in the hemiarthroplasty group and an average of 15 degrees in the arthrodesis group. The success of hemiarthroplasty and the problems of glenoid loosening in the presence of cuff deficiency with upward head displacement have led to the conclusion that humeral hemiarthroplasty is the preferred method for managing complex irreparable tears of the rotator cuff in which the articular surface is destroyed, yet the deltoid muscle is functional. Shoulder arthrodesis is reserved for those patients who have both irreparable tears of the rotator cuff and irreparable deficiencies of the deltoid muscle, or the younger patient with demands for substantial strength at low angles of flexion.

Aged↗
PubMed1991

Repairs of the rotator cuff. Correlation of functional results with integrity of the cuff.

We evaluated the results of 105 operative repairs of tears of the rotator cuff of the shoulder in eighty-nine patients at an average of five years postoperatively. We correlated the functional result with the integrity of the cuff, as determined by ultrasonography. Eighty per cent of the repairs of a tear involving only the supraspinatus tendon were intact at the time of the most recent follow-up, while more than 50 per cent of the repairs of a tear involving more than the supraspinatus tendon had a recurrent defect. Older patients and patients in whom a larger tear had been repaired had a greater prevalence of recurrent defects. At the time of the most recent follow-up, most of the patients were more comfortable and were satisfied with the result of the repair, even when they had sonographic evidence of a recurrent defect. The shoulders in which the repaired cuff was intact at the time of follow-up had better function during activities of daily living and a better range of active flexion (129 +/- 20 degrees compared with 71 +/- 41 degrees) compared with the shoulders that had a large recurrent defect. Similar correlations were noted for the range of active external and internal rotation and for strength of flexion, abduction, and internal rotation. In the shoulders in which the cuff was not intact, the degree of functional loss was related to the size of the recurrent defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Mechanics of glenohumeral instability.

The glenohumeral joint is designed for mobility and is normally lax. It is stabilized in its midrange by its limited joint volume and concavity-compression. It is stabilized at the extremes of motion by its ligaments. An enhanced understanding of these stabilizing mechanisms helps us in the diagnosis and management of glenohumeral instability.

Humans↗
PubMed1991

The effect of capsular venting on glenohumeral laxity.

Anesthetized shoulders are frequently stable against forces applied during drawer and sulcus tests, even though the shoulder muscles are inactive and do not contribute to stability. This passive stability is also evident in the glenohumeral joints of anatomic specimens. The translational laxity of anatomic specimen shoulders was measured, and it was demonstrated that this laxity was substantially increased when air was admitted into the capsule. Eight shoulders, aged 57-87 years, including six contralateral pairs, were analyzed using a six degrees-of-freedom force transducer and a six degrees-of-freedom spatial tracker. Capsules were vented by admitting air ad libitum through an 18-gauge needle. Venting reduced the force necessary to translate the humeral head with respect to the glenoid fossa by an average of 15.3 N (55%) for anterior forces, 10.8 N (43%) for posterior forces, and 19.0 N (57%) for inferior forces. It is likely that passive stability will also be diminished by a similar mechanism in patients with intact but excessively lax capsules. The principle of limited joint volume should be considered and tested when investigating glenohumeral stability.

Aged↗
PubMed1990

The effects of age and peripheral vascular disease on the circulatory and mechanical response of skin to loading.

The skin and subcutaneous soft tissues of amputation residual limbs are required to withstand externally applied loads of greater magnitude than similar tissues of the intact lower limb. Increased age and poor circulatory status may contribute to the increased risk of tissue injury seen in this population. This study evaluates the effects of age and circulatory status as risk factors for skin injury resulting from externally applied forces. Twelve young control (YC), six elderly control (OC) and 11 subjects with peripheral vascular disease (PVD) were studied. After base-line ankle arm index (AAI) measurements, TcPO2 electrodes were applied 10 cm below the knee over the medial surface of the tibia and the muscle belly of tibialis anterior. TcPO2 measurements and tissue displacements were obtained under the influence of incremented, normally oriented, external loads. The sensitivity of the tissues to applied loads was determined by calculating the load at which the TcPO2 reached zero. The stiffness of the tissues (displacement/load) was calculated under high (greater than 40 mm Hg) and low (less than 20 mm Hg) loading conditions. No difference was noted in tissue sensitivity to applied loads between the OC and YC populations. The TcPO2 decreased to zero in the PVD population at significantly lower applied loads than both the OC and YC populations. The tissue stiffness of the PVD and the OC populations over bone was greater than the YC population, but no significant differences were noted between the PVD and the OC populations. In summary, increased age does not result in a greater tissue sensitivity to externally applied loads, in spite of the demonstrated increased tissue stiffness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Translation of the humeral head on the glenoid with passive glenohumeral motion.

We have demonstrated that certain passive motions of the glenohumeral joint are reproducibly accompanied by translation of the head of the humerus on the glenoid. We investigated the relationship of these translations to the position of the glenohumeral joint and to applied torques and forces in seven isolated glenohumeral joints from fresh cadavera, using a six-degrees-of-freedom position sensor and a six-axis force and torque transducer. Reproducible and significant translation occurred in an anterior direction with glenohumeral flexion and in a posterior direction with extension. We also observed translation with cross-body movement. The translation occurring with flexion was obligate in that it could not be prevented by the application of an oppositely directed force of thirty to forty newtons. Operative tightening of the posterior portion of the capsule increased the anterior translation on flexion and cross-body movement and caused it to occur earlier in the arc of motion compared with the intact glenohumeral joint. Operative tightening of the posterior part of the capsule also resulted in significant superior translation with flexion of the glenohumeral joint.

Aged↗
PubMed1990

The relationship of the glenohumeral joint capsule to the rotator cuff.

The glenohumeral joint capsules of 23 shoulders in which the rotator cuff was not torn were studied by gross dissection and histologic methods. The cuff tendons were resected, leaving the intact capsule attached to the bones. This dissection method provided a unique overview of the capsule in situ and allowed the areas of cuff tendon and muscle attachment to be mapped. The capsule was found to be a continuous cylinder between humerus and glenoid. On approximately one-third of the capsule (the portion adjacent to the humeral tuberosities), tight insertions of cuff tendons were noted. The superior segment between subscapularis and supraspinatus contained the coracohumeral ligament. This segment appeared to reinforce the cuff through a transversely oriented band similar to the glenohumeral ligaments.

Aged↗
PubMed1989

Transdermal fentanyl for postoperative pain management. A double-blind placebo study.

A double-blind, placebo-controlled, randomized design was used to evaluate the safety and efficacy of transdermal fentanyl citrate for postoperative pain management in 42 healthy adult patients undergoing major shoulder surgery. Transdermal systems rated to deliver fentanyl citrate at a rate of 75 micrograms/h were applied to the skin immediately prior to surgery and worn for 24 hours. Patients in the active group required significantly less morphine than the placebo group during the 24-hour period that systems were in place (0.8 +/- 0.61 vs 1.3 +/- 0.64 mg/h) and for the first 12 hours after removal (0.3 +/- 0.36 vs 0.5 +/- 0.32 mg/h). The incidence of vomiting was more frequent in the active group than in the placebo group (73% vs 30%), and respiratory rate in the active group was lower than in the placebo group during the 13- to 24-hour interval of system application (14 +/- 3 vs 16 +/- 2 breaths per minute). Nevertheless, transdermal fentanyl appears to be safe and effective after orthopedic surgery in healthy adult patients.

Administration, Cutaneous↗