Medial unicompartmental knee arthroplasty: does tibial component position influence clinical outcomes and arthroplasty survival?

INTRODUCTION

In several recent studies, unicompartmental knee arthroplasty (UKA) produced better functional outcomes than did total knee arthroplasty with 10-year prosthesis survival rates greater than 95%. Nevertheless, UKA is still widely viewed as producing inconsistent results. Tibial component loosening is the leading cause of failure. We consequently sought to identify tibial component position criteria associated with outcomes of medial UKA.

MATERIAL AND METHODS

We conducted a retrospective multicentre study of 559 medial UKAs performed between 1988 and 2010 in 421 patients (262 females and 159 males) with a mean age of 69.51±8.72 years at surgery. We recorded the following radiographic parameters: joint space height, obliquity and slope of the tibial implant, whether the tibial component was perpendicular to the femoral component, and lower limb malalignment. The International Knee Society (IKS) score was used to assess clinical outcomes. Mean follow-up at re-evaluation was 5.17±4.33 years.

RESULTS

The mean 10-year prosthesis survival rate was 83.7±3.5%. Factors associated with decreased prosthesis survival were a greater than 2-mm change in joint space height, a greater than 3° change in tibial component obliquity, a slope value greater than 5° or a change in slope greater than 2°, and more than 6° of divergence between the tibial and femoral components. Residual mechanical varus of 5° or more was also associated with mechanical failure. The only factor associated with worse functional score values was joint space elevation by more than 2mm.

DISCUSSION

The high level of accuracy required for optimal positioning of the tibial component during medial UKA indicates a need for considerable technical expertise and emphasises the conservative nature of the procedure. Optimal positioning is crucial to restore normal knee kinematics and to prevent implant wear and lesions to adjacent compartments.

LEVEL OF EVIDENCE

IV, retrospective study.

Treatment of delayed and nonunions of the humeral shaft using the Seidel locking nail: a preliminary report of five cases

We report the treatment of five cases of delayed/or nonunions of the humerous using the Seidel locking nail. Union occurred in all cases despite two distal unscrewings. Shoulder motion was pain free, with slightly restricted abduction. No subacromial impingement occurred. Elbow motion was slightly limited in extension in two elderly patients, most likely because of previous immobilization. This method of treatment therefore seems to be of value because it avoids iatrogenic risk to the radial nerve and the possible need for bone grafting.

Echinococcus granulosus:isoprinosine treatment of the metacestode stage

The efficacy of short- and long-term treatments with Isoprinosine, an immunomodulatory compound, was studied in Echinococcus granulosus cysts developed in NMRI mice intraperitoneally infected with sheep pulmonary cysts. After treatment, a reduction in the size and number of cysts with macroscopic modifications was observed. The structural alterations included damage or destruction of the protoscoleces and partial destruction of the cyst wall, which predominated at the inner germinal layer level. The efficacy of this drug was evaluated after long-term and short-term treatment. Short-term treatment with a dose of 1 g/kg/day gave better results, with a loss of infectivity of the larval tissue. The well-tolerated long-term treatment with a dose of 2 g/kg/day showed the absence of toxicity of this compound. The survival time of treated animals was greater than that of untreated controls.

Serotonin-induced stimulation of cortisol secretion from human adrenocortical tissue is mediated through activation of a serotonin4 receptor subtype

The occurrence of serotonin in the human adrenal gland was demonstrated both by immuno-histochemical and biochemical approaches. Using specific polyclonal antibodies to serotonin, the presence of numerous immunoreactive cells was revealed by means of the peroxidase-antiperoxidase technique. These cells exhibited the morphological characteristics of mast cells. Combination of high performance liquid chromatography and electrochemical detection showed the presence of substantial amounts of both serotonin and its metabolite 5-hydroxyindolacetic acid in adrenocortical extracts. The role of serotonin in the regulation of steroidogenesis from human adrenocortical slices was studied in vitro using a perifusion system technique coupled to a specific radioimmunoassay for cortisol. Graded doses of serotonin (from 10(-8) M to 3 x 10(-7) M) increased cortisol production in a dose-dependent manner. Prolonged exposure of adrenal fragments to serotonin (10(-7) M) induced a biphasic response, i.e. a rapid and transient increase in cortisol secretion followed by a plateau phase, suggesting the existence of a desensitization phenomenon. The stimulatory effect of serotonin (10(-7) M) was not altered during infusion of the serotonin1 and/or serotonin2 receptor antagonists methysergide (10(-6) M) and ketanserin (10(-6) M), respectively. In contrast, ICS 205 930 (10(-6) M), a non-selective serotonin3/serotonin4 antagonist, totally abolished the response of adrenal slices to serotonin (10(-7) M). The benzamide derivative zacopride, considered as a serotonin4 agonist, induced a robust stimulation of cortisol secretion. In addition, the corticotropic effects of serotonin (10(-7) M) and zacopride (10(-6) M) were not additive. Incubation of adrenocortical fragments with zacopride (10(-6) M) or serotonin (10(-6) M) caused a significant increase in cAMP formation. Taken together, these data suggest that serotonin, locally released by intra-adrenal mast-like cells, may act as a paracrine factor to stimulate cortisol secretion in man. Our results also indicate that serotonin-induced corticosteroid production is mediated through activation of a serotonin4 receptor subtype positively coupled to adenylate cyclase.

Effects of multiple doses of isoprinosine on Echinococcus multilocularis metacestodes

Isoprinosine was given at daily doses of 0.5, 1, 2, and 4 g kg-1 of body weight to jirds that were infected for 3 months with Echinococcus multilocularis metacestodes. The effects of the different drug doses on metacestodes were studied by transmission electron microscopy and biochemical methods. At lower doses, increases in uric acid and adenosine deaminase activity were noted. At 4 g kg-1 of body weight, marked ultrastructural damage with metabolic perturbations was observed.

[Tissue binding of orally administered bismuth in the rat. Effect of the digestive microbial flora]

Strains of E. coli and Str. faecalis, which do not darken in the presence of Bismuth in vitro, and which had been previously isolated from faeces of patients having presented bismuthic myoclonic encephalopathy, were implanted in the digestive tract of axenic rats. Then these monoxenic rats were treated orally for 15 days with bismuth subnitrate (0,24 millimoles = 50 mg/animal/day) and sacrificed on day 16. At this time, levels of bismuth in blood, brain, kidney and femur from these rats did not significantly differ from those obtained from axenic rats or monoxenic rats implanted with the homologous bacterial strains which darken in the presence of bismuth. Conversely, under the same conditions, levels of bismuth in kidney, muscle and femur were significantly lower in holoxenic rats than in axenic rats. Levels of bismuth in kidney and femur were also significantly lower in holoxenic rats than in monoxenic rats implanted with one of the four bacterial strains mentioned above.

Activation of melanogenesis in the beagle by a vasodilator, mecinarone

Mecinarone (18.25 mg/kg twice a day orally for 6 months) induces an increase in melanin content of pigmented skin and mucosae in the Beagle dog. This effect is reversible. This effect is not due to a central or an endocrine mechanism because plasma levels of M.S.H., A.C.T.H. and cortisol remain normal. High levels of Mecinarone are found in melanized areas (skin, hair and non tapetal area of the eye). This effect is reversible. In contrast wih the Beagle, studies in pigmented guinea-pig and rabbit have been negative.

[Results of a double-blind medium-term study comparing effects of timolol maleate and epinephrine in 120 patients with chronic open-angle glaucoma]

A double-blind medium term study of the activity of timolol in chronic open-angle glaucoma was conducted in four French ophthalmological centers, using the same protocol. A total of 119 patients were treated: --60 with timolol; --59 with épinéphrine, for comparison. Results showed a significantly superior efficacy for timolol over épinéphrine, after in weeks of treatment. Good tonometric control was obtained in 81.6% of the patients treated with timolol, against 52.5% of those receiving épinéphrine. In 68% of the glaucomatons patients treated with timolol, good tonometric control was obtained with the lowest dose preparation containing 0.1%. No side-effects were noted during the study, either locally or generally (particularly blood pressure changes).

Hepato- and thyreotoxicity of tifemoxone

The oral toxicity of Tifemoxone, phenoxymethyl-6 tetrahydroxazine-1, 3 thione-2, a new potential antidepressant was studied during 6 months in rats at 30, 85 and 230 mg/kg/d and in beagle dogs at 10, 55 and 300 mg/kg/d. Thyroid hyperplasia and hypoactivity were observed in the rats and dogs plasma triiodothyronine, determined in dogs, was modified. A dose dependent hepatotoxic effect was observed in the rats and dogs. In dogs at low dose, one animal died after B.S.P. test. Water consumption and urinary volume increased, weight loss and anemia appeared at high doses in both rats and dogs. Hair loss was observed in rats and convulsions in dogs. In conclusion, Tifemoxone like tetrahydroxazine thione and some derivatives caused thyreotoxicity, hairlessness and increased in water comsumption and diuresis and in addition it had strong hepatotoxic effect especially in the dog.

Use of Freund's adjuvant arthritis test in anti-flammatory drug screening in the rat: value of animal selection and preparation at the breeding center

The Freund's adjuvant technic, using killed Mycobacterium butyricum suspended in mineral oil, is a refined tool for anti-inflammatory drug evaluation. Its use has long been reserved for testing and not for screening due to technical problems in the preparation of valid animal models. After reviewing the methodology, the authors demonstrated that the availability of arthritic rats from a modern breeding center (Charles River France, SA, Elbeuf, France) make the procedure applicable to drug screening. This has both practical and economic advantages. The animals can be used as test organisms for drug evaluation 14 da after treatment. Three criteria for measuring the effectiveness of anti-arthritic drugs have been established: an arithritic index determined by examination of the 4 paws; changes in the erythrocyte sedimentation rate; and changes in levels of plasma fibrinogen. The curative activity of test substances can be evaluated by a single series of measurements of these 3 criteria after 14 da of treatment. This test was compared with 2 others; edema of the paw induced by the subcutaneous injection of kaolin or carrageenan, and was found to be superior.

Pharmacological study of a new substance, mecinarone

Mecinarone, a benzofuranic chalcone, shows considerable vasodilating activity on the peripheral and cerebral circulation. The intramuscular irrigation is thus improved and the cerebral blood supply increased. This vasodilating activity is accompanied by only a slight drop in the systemic arterial pressure and occurs without cardiac depression. Mecinarone has also antibradykinin, antiserotonin and antiaggregation properties which added to the vasodilating activity, greatly increase its pharmacological interest.