Biomedical subjects

Steen Lund Jensen

Publications and source records attributed to Steen Lund Jensen.

5 recordsLinked to original sources

PubMed2005

Wrist stability after experimental traumatic triangular fibrocartilage complex lesions.

PURPOSE: The aim of this study was to evaluate changes in stability of the wrist after experimental traumatic triangular fibrocartilage complex lesions. METHODS: Sixteen cadaver wrist specimens were included: 8 were fixed in neutral rotation of the forearm, 4 in maximal supination, and 4 in maximal pronation. The specimens were tested in a multiangle and torque measuring instrument. First the intact specimen was tested, second a dorsal arthrotomy was performed, and the third test was with 1 of 4 different experimental lesions according to Palmer's classification of traumatic triangular fibrocartilage complex lesions (1A-1D). Forced radioulnar deviation and internal/external rotation were recorded with a load of 0.75 Nm in the interval -60 degrees to +60 degrees of flexion. RESULTS: We found the 1C lesion to be highly significantly related to wrist stability. Forced radioulnar deviation and forced internal/external rotation were altered significantly in 35 degrees of wrist extension. The other lesions did not alter the stability of the wrist significantly and the rotation of the forearm had no influence on the outcome. CONCLUSIONS: The 1A lesion does not alter significantly wrist stability and hence the common treatment by a two-third excision of the central part of the disk will not affect wrist stability. A 1C lesion alters significantly the stability of the wrist. At 35 degrees of wrist extension forced radioulnar deviation and forced internal/external rotation were altered significantly; this might be used in a clinical test for a 1C lesion. The rotation of the forearm has no influence on the outcome.

Aged↗

PubMed2003

[Defects in the surgical glove barrier. Single or double gloves].

The purpose of wearing surgical gloves is to provide an antimicrobial barrier between the hands of the surgical staff and the tissues of the patient. Glove perforations are common, depending on the function of the staff member and the duration and nature of the surgery. In addition, gloves can hydrate, which is also a potential route of infection. The use of two pairs of gloves (double gloves) efficiently reduces both the perforation rate and the hydration of the glove barrier. Decreased dexterity and tactile sensitivity, however, are common objections, which keep many surgeons from wearing double gloves. Moreover, they seem to have little practical importance. Neither single nor double gloves have proved their effectiveness in terms of actual infections, but it seems rational to maintain a surgical glove barrier. Double gloves can be recommended as a simple means of improving the integrity of this barrier.

Blood-Borne Pathogens↗

PubMedDate not supplied

Elbow joint laxity after experimental radial head excision and lateral collateral ligament rupture: efficacy of prosthetic replacement and ligament repair.

The objectives of this experimental study were to investigate the effect of radial head excision and lateral collateral ligament (LCL) division on elbow joint laxity and to determine the efficacy of radial head prosthetic replacement and LCL repair. Valgus, varus, internal rotation, and external rotation of the ulna were measured during passive flexion-extension and application of a 0.75-Nm torque in 6 intact cadaveric elbows and after (1) either excision of the radial head or division of the LCL, (2) removal of both constraints, (3) isolated radial head prosthetic replacement, (4) isolated LCL repair, and (5) radial head replacement combined with LCL repair. Isolated radial head excision increased varus (mean, 4.8 degrees) and external rotatory laxity (mean, 7.1 degrees), as did isolated LCL division (mean, 14.1 degrees for varus; mean, 14.7 degrees for external rotation). After removal of both constraints, varus and external rotatory laxities were increased by 19.0 degrees and 20.1 degrees, respectively, compared with the intact specimens. Isolated radial head replacement reduced mean varus laxity to 14.6 degrees and mean external rotatory laxity to 14.8 degrees. Isolated LCL repair normalized varus laxity but resulted in a 2.9 degrees increase in external rotatory laxity. The combined procedures restored laxity completely. The radial head is a constraint to varus and external rotation in the elbow joint, functioning by maintaining tension in the LCL. Still, removal of both constraints induces severe laxity, and in this case, prosthetic replacement may substitute for the constraining capacity of the native radial head. The combination of LCL repair and radial head replacement restores laxity completely, but an isolated LCL repair performs almost as well, probably by compensating for the ligamentous tension lost from radial head excision.

Adult↗

PubMedDate not supplied

Functional anatomy of the lateral collateral ligament complex of the elbow: configuration of Y and its role.

A previous anatomic study has revealed that the lateral collateral ligament (LCL) complex of the elbow has a Y-shaped configuration, which consists of a superior, an anterior, and a posterior band. The LCL complex, including the annular ligament, functions as a 3-dimensional (3D) Y-shaped structure. On the basis of this concept, joint laxity after transection of the anterior band was studied in 5 normal, fresh-frozen cadaver elbows with a 3D kinematic testing apparatus. Cutting the anterior band produced significant laxity to varus torque with a mean 5.9 degree at 10 degree of elbow flexion and caused significant laxity to torque in external rotation with a mean 8.5 degree at 40 degree of flexion. No significant laxity was observed during application of valgus or internal rotational torque. Further transection of the posterior band resulted in gross instability with dislocation of the ulnohumeral joint. The laxity occurring after severance of the anterior band suggests that these fibers play a role in preservation of elbow stability against varus and external rotational torque. These results indicate that the LCL functions as a complex with a Y structure and not as an isolated linear ligament. A concept of conjoint point is hypothesized for the function of the LCL complex to restrain posterolateral rotatory instability.

Aged↗

PubMedDate not supplied

Radiohumeral stability to forced translation: an experimental analysis of the bony constraint.

Radiohumeral stability to forced translation was experimentally analyzed in 8 osteocartilaginous joint preparations. The joints were dislocated in 8 centrifugal directions at 12 different combinations of joint flexion and rotation while a constant joint compression force of 23 N was applied. Stability was measured as the maximum resistance to translation. On average, the specimens could resist a transverse force of 16.4 N (range, 13.0-19.1 N). Stability was greater in some directions than in others. Rotating the joint changed the direction at which stability was greatest, whereas joint flexion did not. In supination, the greatest stability was observed for anteromedial dislocations, in neutral rotation for posteromedial dislocations, and in pronation for posterolateral dislocations. The findings from this study indicate systematic variations in wall height around the radial head concavity as well as individual variations in joint constraint. This may have implications for the treatment of conditions involving radiohumeral joint dislocation.

Cadaver↗