Total knee arthroplasty in valgus knees: predictive preoperative parameters influencing a constrained design selection.

INTRODUCTION: In valgus knees, ligament balance might remain a challenge at total knee prostheses implantation; this leads some authors to systematically propose the use of constrained devices (constrained condylar knee or hinge types...). It is possible to adapt the selected level of constraints, by reserving higher constraints to cases where it is not possible to obtain final satisfactory balance: less than 5 degrees of residual frontal laxity in extension in each compartment, and a tibiofemoral gap difference not in excess to 3 mm between flexion and extension. HYPOTHESIS: It is possible to establish preoperative criteria that can predict a constrained design prosthetic implantation at surgery. MATERIALS AND METHODS: A consecutive series of 93 total knee prostheses, implanted to treat a valgus deformity of more than 5 degrees was retrospectively analysed. Preoperatively, full weight bearing long axis AP views A-P were performed: hip knee angle (HKA) averaged 195 degrees (186 degrees to 226 degrees), 36 knees had more than 15 degrees of valgus, and 19 others more than 20 degrees of valgus. Laxity was measured by stress radiographies with a Telos system at 100 N. Fifty-two knees had preoperative laxity in the coronal plane of more than 10 degrees. Fourteen knees had more than 5 degrees laxity on the convex (medial) side, 21 knees had more than 10 degrees laxity on the concave (lateral) side. Statistical assessment, using univariate analysis, identified the factors that led, at surgery, to an elevated constraint selection level; these factors of independence were tested by multivariate analysis. Logistical regression permitted the classification of the said factors by their odds ratios (OR). RESULTS: High-constraints prostheses (CCK type) numbered 26 out of 93 implantations; the other total knee prostheses were regular posterostabilized (PS) prostheses. Statistically, the preoperative factors that led to the choice of a constrained prosthesis were: (1) valgus severity as measured by HKA (PS=193 degrees, CCK=198 degrees), (2) increased posterior tibial slope (PS=4.8 degrees, CCK=6.5 degrees), (3) low patellar height (using Blackburne and Peel index PS=0.89, CCK=0.77), (4) severity of laxity in valgus (PS=2.3 degrees, CCK=4.3 degrees). Among all these factors, the only independent one was laxity in valgus (convex side laxity) (p=0.0008). OR analysis showed a two-fold increased probability of implanting an elevated constraints prosthesis for each one degree increment of laxity in valgus. DISCUSSION: This study demonstrated that it was not the valgus angle severity but rather the convex medial side laxity that increased the frequency of constrained prostheses implantation. Other factors, as a low patellar height or an elevated posterior tibial slope, when associated, potentiate this possible prosthetic switch (to higher constraints) and should make surgeons aware, in these situations, of encountering difficulties when establishing ligament balance. LEVEL OF EVIDENCE IV: Therapeutic retrospective study.

[The safety and immunogenicity of an heptavalent pneumococcal polysaccharide conjugate vaccine (Prevenar) administered in association with a whole-cell pertussis-based pediatric combination vaccine (DTP-IPV/PRP-T) to French infants with a two-, three-, and four-month schedule]. / Tolérance et immunogénicité d'un vaccin pneumococcique osidique conjugué heptavalent (Prevenar) administré en association avec une combinaison vaccinale pédiatrique (DTCoq-Polio/Hib) à des nourrissons selon le schéma vaccinal français à l'âge de deux, trois et quatre mois.

UNLABELLED: Invasive pneumococcal disease is presently a leading cause of mortality due to bacterial infectious diseases in French children less than 2 years of age, and only the pneumococcal conjugate vaccines induce a protective immune response for those within this vulnerable age group. MATERIAL AND METHODS: The safety and immunogenicity of a heptavalent pneumococcal polysaccharide conjugate vaccine (PREVENAR was tested in French infants immunized with the 2, 3 and 4 month French schedule as part of an open, randomized, comparative clinical study, in association with a whole-cell pertussis-based pediatric combination vaccine. RESULTS: In the PREVENAR plus DTP-IPV/Hib association group, 90.6-100% of children achieved a post-dose three threshold IgG concentration of >0.15 microg/ml against each of the seven pneumococcal serotypes. Regarding immunogenicity, no interference with the antibody response to the various antigenic components of the DTP-IPV/Hib vaccine was observed. Local reactions were significantly less frequent at the PREVENAR injection site than at the DTP-IPV/Hib injection site; there was no increase in systemic adverse events in the vaccine association group compared to the DTP-IPV/Hib alone group, further exception of fever >38 degrees C which was more frequently reported in the PREVENAR + PENTACOQ group following the second dose of vaccines (56% vs. 35%); no serious adverse event could be considered to be related to the PREVENAR immunization in this study. CONCLUSION: The heptavalent pneumococcal conjugate vaccine is immunogenic when administered at 2, 3 and 4 months. PREVENAR can be administered simultaneously with the DTP-IPV/Hib combination vaccine.

Autonomic hyperreflexia.

Autonomic hyperreflexia presents as acute episodes of uninhibited reflex sympathetic hyperactivity in the patient with chronic high spinal cord lesion. An understanding of the pathophysiology of this syndrome is paramount in its successful management. It occurs in patients with chronic spinal cord lesions above T7 upon stimulation below the lesion, particularly distention of the urinary bladder. The main clinical signs are paroxysmal hypertension and bradycardia. Management of acute episodes should include withdrawal of the initiating stimulus and possibly administration of pharmacological agents such as nifedipine and nitroprusside. Long-term treatment may involve radical surgery. Despite its technical difficulties, spinal block is still the anesthesia of choice in these patients.

Cardiovascular changes during laparoscopic cholecystectomy.

Although the technique of laparoscopic cholecystectomy has increasing appeal, physiologic data to support the safety of this procedure are lacking. We studied the cardiovascular changes in 16 patients undergoing laparoscopic cholecystectomy, using impedance cardiography as a noninvasive means of continuous monitoring of cardiac output. Serial measurements of mean arterial pressure (MAP), heart rate (HR), intraperitoneal pressure and expired carbon dioxide tension (PECO2) were also recorded. Results revealed a decrease of 30 percent (p < 0.001) in cardiac index and 5 percent (p = 0.089) in HR, along with increases of 15 percent (p < 0.001) in MAP and of 79 percent (p < 0.001) in the calculated total peripheral resistance index. This elevation in afterload could lead to both an increase in myocardial oxygen consumption and to the potential risk of myocardial ischemia and possibly infarction or congestive heart failure, or both, in patients who are susceptible. The data suggest that patients with a history of cardiac disease should have preoperative cardiac evaluation and be closely monitored during laparoscopic cholecystectomy, as in any other extensive operation.