SummaryIncreasing evidence suggests that local blood flow should be monitored during microdialysis (MD) as the recovery of analytes is affected by local blood flow. At present ethanol clearance is the standard technique for this purpose, but it is not functional at very low perfusion velocities. Here, we introduce a technique for MD whereby local tissue blood flow is recorded by the use of urea clearance (changes inflow⁄outflow concentration), in conjunction with measurements of tissue metabolism (glucose, lactate and puruvate). MD probes were inserted into the gracilis muscle of 15 rats and perfused with a medium containing urea (20 mmol l )1 ). Changes in muscle blood flow were made by addition of noradrenaline (5 lg ml) to the perfusion medium at two perfusion velocities (0AE6 and 0AE4 ll min )1 ). The clearance of urea from the perfusion medium was then calculated and examined in relation to the dose of noradrenaline and to the coexisting changes in extracellular metabolites. The results showed reproducible and dose-dependent changes in blood flow that were induced by noradrenaline. These were characterized by dose-dependent changes in the urea clearance as well as blood-flow-specific changes in the MD metabolic markers (reduction in glucose and increase in lactate). The sensitivity for blood flow changes as assessed by urea clearance (MD) was increased at 0AE4 compared with the 0AE6 ll min )1 perfusion speed. The results indicate that inclusion of urea to the perfusion medium may be used to monitor changes in skeletal muscle blood flow at low perfusion velocities and in parallel assess metabolic variables with a high recovery (>90%).

The effects of a shortened post-operative mobilization programme following flexor tendon repair in zone 2 in the hand were examined in a prospective, randomized study. 91 digits in 82 patients were included in the study. All injured tendons were repaired within 24 hours and all patients were subjected to the same mobilization programme during the first 6 weeks using a passive flexion-active extension régime. After 6 weeks the patients were randomized into two groups; in group A full activity was allowed after 8 weeks while in group B unrestricted use of the injured hand was not allowed until 10 weeks after the tendon repair. Functional results were compared using the Louisville, Tsuge and Buck-Gramcko assessment systems. Grip-strength was measured 16 weeks after repair, subjective assessment of hand function was recorded on a visual analogue scale, and absence from work was registered. No significant differences were observed between the groups regarding functional results, rupture rates, grip strength or subjective assessment, but absence from work was reduced by 2.1 weeks with the shorter mobilization programme. Using the described régime, full activity can be encouraged 8 weeks after flexor tendon repair in zone 2 of the hand without adverse effects on functional results or increased risk of rupture of the repair.

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The results following primary and delayed primary repair in zone 2 flexor tendon injuries were evaluated in 85 fingers of 79 patients using immediate controlled mobilization post-operatively. In 31 patients a conventional Kleinert technique was used. In the remaining 48 patients a modified technique was used with rubber band traction to all fingers instead of only to the injured one. Also a shorter dorsal splint was used in order to secure extension of the PIP and DIP joints. The results were improved and the time of treatment was reduced.

Volar plate fixation of unstable fractures of the distal radius is preferred by a majority of surgeons today. One known complication is the rupture of flexor tendons. The aim of this paper is to present flexor tendon ruptures after volar plate fixation analysing the clinical outcome after tendon surgery, aetiology, and methods of prevention. Seventeen consecutive ruptures in 14 patients were included. The incidence was 1.4%. Three patients declined tendon surgery. Eleven patients were treated with a free tendon graft. Only two patients showed excellent results regarding mobility in the thumb and/or fingers. Analysis of radiographs demonstrated sub-optimal placement of plate or screws in all cases. Rupture of a flexor tendon is a serious complication where the functional outcome after surgical reconstruction is uncertain. Early removal of the plate when the placement is sub-optimal or when local volar tenderness appears would probably prevent many ruptures.