Should return to pivoting sport be avoided for the secondary prevention of osteoarthritis after anterior cruciate ligament reconstruction? A prospective cohort study with MRI, radiographic and symptomatic outcomes.

OBJECTIVE: To evaluate if returning to pivoting sport following anterior cruciate ligament reconstruction (ACLR) is associated with longitudinal structural and symptomatic osteoarthritis outcomes. DESIGN: Eighty-one adults aged 18-50 years were followed prospectively 1- to 5-years post-ACLR. Return to pivoting sport was assessed at 1-, 3- and 5-years. Longitudinal changes in osteoarthritis features were evaluated from 1- and 5-year magnetic resonance imaging (MRI)s using MRI Osteoarthritis Knee Score (MOAKS). Radiographic osteoarthritis and self-reported knee symptoms, function and quality of life were assessed using the Osteoarthritis Research Society International (OARSI) atlas and Knee injury Osteoarthritis Outcome Score (KOOS), respectively, at 5 years post-ACLR. Generalised linear models (adjusted for baseline characteristics) assessed whether returning to pivoting sport was associated with risk of worsening osteoarthritis features on MRI, radiographic osteoarthritis and KOOS. RESULTS: Thirty participants returned to pivoting sport 1-year post-ACLR and 50 returned at any time (i.e., 1-, 3- or 5-years). Returning to pivoting sport was not associated with worsening of any MRI osteoarthritis feature (risk ratio (RR) range: 0.59-2.91) or 5-year KOOS (ß range: -2.73-3.69). Returning to pivoting sport at 1-year and up to 5-years post-ACLR was associated with a 50% (RR 0.49, 95%CI 0.10-2.37) and 40% (RR 0.60, 95%CI 0.16-2.17) reduced risk of radiographic osteoarthritis, respectively, but these risk reductions were inconclusive due to wide confidence intervals. CONCLUSION: After ACLR, returning to pivoting sport was not associated with increased risk of worsening knee osteoarthritis features on MRI, radiographic osteoarthritis or knee symptoms. Participation in pivoting sport need not be avoided as part of osteoarthritis secondary prevention strategies.

Homocysteine in dogs with systemic inflammatory response syndrome.

OBJECTIVES: To compare serum concentrations of homocysteine in healthy dogs and those fitting the criteria for systemic inflammatory response syndrome and to compare these values to commonly measured B-vitamins. METHODS: Study dogs were classified into non-infectious systemic inflammatory response syndrome or sepsis groups and blood was drawn on Day 1 of the patient's hospitalisation for measurement of serum homocysteine, folate and cobalamin concentrations. Homocysteine concentration was measured in 51 clinically healthy dogs to serve as the control group. RESULTS: A statistically significant difference was found between the homocysteine concentrations of the healthy group when compared to non-infectious systemic inflammatory response syndrome and sepsis groups. Homocysteine values were not correlated with folate, cobalamin or APPLEfast severity scores. Homocysteine concentrations were significantly lower in sick dogs when compared to the control group, which is dissimilar to the human population. CLINICAL SIGNIFICANCE: The clinical significance of homocysteine changes in critically ill dogs is currently unknown.

Riboflavin deficiency, metabolic rate and brown adipose tissue function in sucking and weanling rats.

1. The effects of riboflavin deficiency on growth, whole-body oxygen consumption, cytochrome c oxidase (EC 1.9.3.1) activity and GDP-binding capacity of brown adipose tissue were measured in three groups of rats: sucking pups, weanling rats, and dams. Control groups were weight-matched, pair-fed or fed ad lib. 2. Riboflavin deficiency reduced growth rate and increased the activation coefficient of erythrocyte glutathione reductase (NAD(P)H) (EC 1.6.4.2), as predicted. In sucking pups it also reduced whole-body O2 consumption per unit body-weight, especially after noradrenaline stimulation. In weanling rats, however, it increased O2 consumption both before and after noradrenaline stimulation. 3. Cytochrome c oxidase (EC 1.9.9.1) activity of brown adipose tissue was not consistently affected by riboflavin deficiency. Binding of [3H]GDP to the mitochondria was increased in the deficient weanling rats. 4. Weanling rats therefore, seemed better able to withstand the effects of severe depletion. Their reduced growth and increased non-shivering thermogenesis helped to counteract the unfavourable ratio of riboflavin:other tissue-building materials. The relevance for thermoregulation in riboflavin-deficient children is discussed.

Liberation of 14CO2 from 14C-fatty acids by riboflavin-deficient sucking rat pups: a study of 14C-Octanoate and 14C-palmitate oxidation in vivo.

To test the hypothesis that impaired fatty acid oxidation in the mitochondria of riboflavin-deficient rats may be reflected in impaired rates of fatty acid oxidation to carbon dioxide in vivo, the conversion of 14C-labelled fatty acids to 14CO2 was measured in rat pups. Sucking pups were selected, since whole body energy expenditure was reduced by riboflavin deficiency in this age group. A gas-flow apparatus was designed, to permit the collection of expired CO2 over a 4 hr period, in pups maintained at constant temperature. 14C-octanoate and 14C-palmitate, given by intraperitoneal injection, were oxidised to 14CO2, with peak production rates at 20 min and at 30 min respectively. Cumulative recoveries of the injected 14C were: ca. 50% of the dose for 14C-octanoate, and ca. 20% of the dose for 14C-palmitate, during 4 hr collection of expired air. Per unit of body weight, the rates and extents of oxidation of each fatty acid substrate in riboflavin-deficient pups were not significantly reduced in comparison with their pair-fed or ad-lib fed, riboflavin-sufficient controls. This study a) has confirmed the feasibility of the 14C-fatty acid-breath test assay for sucking rat pups; b) has excluded the possibility of massive reductions due to riboflavin deficiency in the oxidation of two fatty acid substrates, and c) has provided estimates of biological variation of these indices, which will assist future studies.