EXCISION OF OS LUNATUM IN THE TREATMENT OF LUNATOMALACIA

The small size of Os lunatum and its nature as an articulation element which movement is similar to that of a "tank track" reduces the opportunities for free functioning of the radiocarpal joint after lunate damage. During a 15-year period (1982-1997) a total of 13 patients underwent an excision of Os lunatum. They were 9 males and 4 females aged between38 and 60 years (mean age of 41 years and 3 months). Eight patients were at 111A stage after Lichtman, two - at II1Ð’, and three - at IV stage of the disease. Intercarpal arthodesis after O. Craner (1966) was additionally performed in 9 patients after extirpation  of Os lunatum under conditions of a severe lunate collapse. A good result (of 22-26 scores) was obtained in seven patients, a satisfactory' one (of 13-15 scores) - in 3 patients but a poor one (below 8 scores) in 2 patients only. The good results after the application of the excision and particularly of the resection of Os lunatum proved the appropriateness of this method for the treatment of Kienhocks's disease at stages III and IV in case of absent arthrotic alterations of radius, Os capitatum, and Os scaphoideum. The intercarpal arthodesis ensured anaesthesia and carpal stablility despite a certain restriction of range of motion

ASEPTIC NECROSES OF CARPAL BONES

No abstrac

INDICATIONS FOR "LEVEL" OPERATIONS IN THE TREATMENT OF ASEPTIC NECROSES OF CARPAL BONES

During a five-year period (1992-1996) a total of 21 patients with aseptic necroses of os lunatum (morbus Kienbock) and os scaphoideum (morbus Praisser) were treated. Five male patients with morbus Kienbock and ulna negative variance, at a mean age of 29 years, underwent surgical treatment with shortening of the radius. The author argued in favour of radial shortening rather than of ulnar lengthening. Oblique osteotomy with radial shortening with volar access was considered the most appropriate surgical method. It demonstrated several advantages related with bone union and proximal carpal row decompression and we had excellent postoperative results

USE OF EXTERNAL FIXATOR FOR LIGAMENTOTAXIS IN FRAGMENTED DISTAL RADIAL FRACTURES

No abstrac

ANATOMICAL FEATURES OF OS LUNATUM: SIGNIFICANCE IN THE WRIST JOINT STATICS AND MECHANICS

Os lunatum cannot resist this pressure which is considered to be one of the reasons for the development of Kienbock s disease. This resistance to the considerable pressure depends on some morphological features of the wrist bones and ofOs lunatum in particular. The variations of the anatomical features were studied on 12 cadaver wrists. The results showed that Os lunatum could contact the bones of the distal wrist row and those of the forearm in different ways: i) with Os capitatum and with two separated articular surfaces for radius and discus articularis - in 33,33 % and ii) Os capitatum, Os hamatum and with two separated articular surfaces for radius and discus articularis - in 66,67 %

ANATOMICAL PREDISPOSITIONS FOR CHOICE OF RADIUS OR ULNA OSTEOTOMY IN "ULNA MINUS" VARIANCE AND KIENBOCK'S DISEASE

Recently, the surgical level for "ulna minus"-variance correction gained popularity in the treatment of Kienbock's disease. Our study aimed at investigating both A. nutricia radii and A. nutricia ulnae in site of branching and localization of Foramen nutricium on the ulna and radius. Cadaver material from 23 upper extremities was used after dissection along with bone material from 82 ulna and 86 radius specimens. A. nutricia radii originated from A. interossea anterior in 100 % of the cases while A. nutricia ulnae initiated from A. interossea anterior in 73,91 % of the cases, directly from A. ulnaris - in 13,04 %, from A. interossea communis - in 4, 35 %, and from A. recurrens ulnaris - in 8, 70 %. Based on these and previously reported data about Foramen nutricium localization along the radius and ulna the reasons for the preferred radius shortening to the ulna lengthening as well as its choice as a most suitable site for "level" osteotomy in the treatment of Kienbck's disease were discussed

Anisotropic Fermi Contour of (001) GaAs Holes in Parallel Magnetic Fields

We report a severe, spin-dependent, Fermi contour anisotropy induced by parallel magnetic field in a high-mobility (001) GaAs two-dimensional hole system. Employing commensurability oscillations created by a unidirectional, surface-strain-induced, periodic potential modulation, we directly probe the anisotropy of the two spin subband Fermi contours. Their areas are obtained from the Fourier transform of the Shubnikov-de Haas oscillations. Our findings are in semi-quantitative agreement with the results of parameter-free calculations of the energy bands.Comment: 4 pages, 4 figure

Anisotropic composite fermions and fractional quantum Hall effect

We study the role of anisotropy on the transport properties of composite fermions near Landau level filling factor $\nu=1/2$ in two-dimensional holes confined to a GaAs quantum well. By applying a parallel magnetic field, we tune the composite fermion Fermi sea anisotropy and monitor the relative change of the transport scattering time at $\nu=1/2$ along the principal directions. Interpreted in a simple Drude model, our results suggest that the scattering time is longer along the longitudinal direction of the composite fermion Fermi sea. Furthermore, the measured energy gap for the fractional quantum Hall state at $\nu=2/3$ decreases when anisotropy becomes significant. The decrease, however, might partly stem from the charge distribution becoming bilayer-like at very large parallel magnetic fields