Correction of Madelung's deformity by the Ilizarov technique.

We present our experience with correction of Madelung's deformity by the Ilizarov technique. Seven patients (eight deformities) were treated by osteotomy of the radius with subsequent lengthening and angular correction. They were reviewed at a mean of 30 months (1.5 to 5.5 years). At the time of operation their mean age was 19 years (9 to 44). At follow-up all were free from pain and supination had improved by a mean of 34 degrees and pronation by 9 degrees. Flexion had increased in most cases with a median increase of 15 degrees, but only one patient gained further extension. Radial and ulnar deviation were increased by a mean of 6 degrees and 9 degrees, respectively. Radiographic measurements showed that the mean volar angulation had been reduced from 25 degrees to 11 degrees, ulnar inclination from 45 degrees to 30 degrees and carpal malalignment (volar translation) from 7 to 2 mm. The mean lengthening of the radius was 12 mm (6 to 25). All the patients were satisfied with the functional and cosmetic results.

Madelung deformity treated with Ilizarov technique: a report of two cases.

Two children with painful and progressive Madelung deformities were treated by osteotomy of the radius and subsequent angular correction and bone lengthening using the Ilizarov technique. Both children were radiologically improved and free of pain at follow-up.

Unicompartmental arthroplasty of the knee. Cadaver study of the importance of the anterior cruciate ligament.

The tibiofemoral articulation on horizontal and 10 degrees tilted tibial components was examined radiographically in 20 cadaver knees after lateral arthroplasty, and after cutting the anterior cruciate ligament in 10 knees with medial and 10 with lateral arthroplasty. Articulation took place more posteriorly on the horizontal components at any degree of flexion examined; a correlation was found between the operation-induced change in the inclination of the lateral tibial plateau and the point of articulation. Based on the regression equations, the expected point of articulation on an arbitrarily chosen component placement could be calculated for any degree of flexion provided the preoperative inclination was known. Cutting the anterior cruciate ligament caused articulation to move posteriorly on the tibial component at both medial and lateral arthroplasty. We concluded that it was possible to estimate the tilt of the tibial component that was required to avoid marginal articulations when the preoperative slope of the tibial plateau was known. Absence of the anterior cruciate ligament seems to contraindicate unicompartmental arthroplasty.

Unicompartmental arthroplasty of the knee. Cadaver study of tibial component placement.

In 30 knee preparations the median posterior inclination (tilt) of the medial tibial plateau was 10 degrees (5 degrees-15 degrees). Following medial compartmental arthroplasty in 20 knees, 10 with horizontal, and 10 with 10 degrees tilted tibial components, the point of articulation was determined radiographically. For the combinations of tibial angle and knee flexion that represent the initial 60 per cent of the stance phase, articulation took place more posteriorly on the horizontal components; there was a correlation between the operation-induced change of the tibial inclination and articulation. Articulation took place far posterior on horizontal components inserted in knees with a steep posterior tilt. We concluded that both the component placement and the preoperative inclination of the tibial plateau determine where on the tibial component articulation takes place. An optimal, central articulation with this set-up is obtained when the component is inserted with the same posterior tilt as that of the original articular surface.

Experimental analysis of Hoffmann external fixation in various mountings.

The mechanical properties of four different configurations of the Hoffmann external fixation system were tested in an experimental setup using 4-mm stainless steel pins. Furthermore, stainless-steel pins and titanium pins 5 mm in diameter were applied in one of the fixators. The evaluation of the results was based on a paired t-test, with P less than 0.05 as the significance level. The quadrilateral transfixing Hoffmann-Vidal frame (HVF) proved to be the most rigid fixator under all loading conditions. The unilateral frame type supplied with two connecting bars and four ball joints was significantly more rigid than the unilateral single-bar device. By increasing the pin diameter from 4 to 5 mm a further increase of stiffness could be achieved, thus reaching about two-thirds of the rigidity of the HVF. The difference between titanium and stainless steel pins was not significant. Common for all the frame mountings was a fivefold greater rigidity in the lateral direction (in the plane of the pins) than in the anteroposterior direction (perpendicular to the pins).

Multiflanged ventricular Portnoy catheter for hydrocephalus shunts.

In 77 patients with hydrocephalus the Portnoy ventricular catheter was incorporated in ventriculoatrial or ventriculoperitoneal shunts. Occlusion of the catheter by brain debris was avoided and the number of choroid plexus obstructions was reasonable low (5%). The flanges of the catheter cannot prevent the catheter from being pushed into the brain parenchyma. The ideal ventricular catheter has not yet been found, but the multiflanged Portnoy catheter seems to be the best at present.