Pain and knee function in relation to degree of bone bruise after acute anterior cruciate ligament rupture.

It is unknown whether the bone bruise that occurs in connection with acute anterior cruciate ligament (ACL) rupture is causing pain and dysfunction. We followed prospectively 17 patients [10 men, seven women, mean age 28 years (range 23-34)] with acute ACL rupture for 2 months. A magnetic resonance imaging (MRI) scan was performed shortly after the injury, and at 2 weeks, 1 month and 2 months. The patients reported the level of pain every day and filled in a Knee injury and Osteoarthritis Outcome Score sheet in connection with MRI. For every MRI of the knee, volume of bone bruise was calculated, and intensity was visually graded. Our study showed a reduction of the pain to 50% approximately 2 weeks after the injury, at which time the bone bruise was at maximum. There was a significant relationship between pain and the volume and intensity of the bone bruise in the medial tibia condyle, as well as pain and the bone bruise volume of the lateral femoral condyle. Patients with bone bruise of the medial tibia and patients with meniscal lesions had more pain. It is suggested that pain and decreased function after acute ACL injury most likely is related to soft tissue and cartilage injury and not to bone bruise.

The effect of bracing on extension strength in patients with ACL insufficiency.

One of the problems following an anterior cruciate ligament (ACL) injury is to regain strength. We tested 11 patients (5 men, 6 women), mean age 28.4 years, with unilateral ACL insufficiency, with two braces (Donjoy Legend, and Bledsoe Brace Force III) versus a placebo brace. The patients were tested on a Biodex Dynamometer at 60 and 180 deg/s in an isokinetic mode. The experiment was designed as a comparative study in a cross-over design with the stable knee as the patient's own control. We found no statistically significant effect of the two braces compared to a placebo brace under the test conditions, and no correlation between knee laxity and the effect of bracing.

Middle cerebral artery blood velocity and cerebral blood flow and O2 uptake during dynamic exercise.

Results obtained by the 133Xe clearance method with external detectors and by transcranial Doppler sonography (TCD) suggest that dynamic exercise causes an increase of global average cerebral blood flow (CBF). These data are contradicted by earlier data obtained during less-well-defined conditions. To investigate this controversy, we applied the Kety-Schmidt technique to measure the global average levels of CBF and cerebral metabolic rate of oxygen (CMRO2) during rest and dynamic exercise. Simultaneously with the determination of CBF and CMRO2, we used TCD to determine mean maximal flow velocity in the middle cerebral artery (MCA Vmean). For values of CBF and MCA Vmean a correction for an observed small drop in arterial PCO2 was carried out. Baseline values for global CBF and CMRO2 were 50.7 and 3.63 ml.100 g-1.min-1, respectively. The same values were found during dynamic exercise, whereas a 22% (P < 0.0001) increase in MCA Vmean was observed. Hence, the exercise-induced increase in MCA Vmean is not a reflection of a proportional increase in CBF.