Clinical biomechanics of instability related to total knee arthroplasty

Background

Tibiofemoral instability is a common reason for total knee arthroplasty failure, and may be attributed to soft tissue deficiency and incorrect ligament balancing. There are many different designs of implant with varying levels of constraint to overcome this instability; however there is little advice for surgeons to assess which is suitable for a specific patient, and soft tissue balance testing during arthroplasty is very subjective.

Method

The current theories on primary and secondary soft tissue restraints to anterior/posterior, varus/valgus, and internal/external rotational motion of the knee are discussed. The paper reviews biomechanics literature to evaluate instability in the intact and implanted knee.

Findings

The paper highlights important intra- and extra-capsular structures in the knee and describes the techniques used by clinicians to assess instability perioperatively. In vitro cadaveric studies were found to be a very useful tool in comparing different implants and contributions of different soft tissues.

Interpretation

In vitro cadaveric studies can be utilised in helping less experienced surgeons with soft tissue releases and determining the correct implant. For this to happen, more biomechanical studies must be done to show the impact of release sequences on implanted cadavers, as well as determining if increasingly constrained implants restore the stability of the knee to pre-deficient conditions.     

Development and Validation of the GI-Cognitions Questionnaire

Patients with irritable bowel syndrome (IBS) have been shown to have catastrophic cognitions regarding the social and occupational consequences of GI symptoms. Moreover, the efficacy of cognitive–behavioral therapy for IBS may be partially mediated by reductions in such cognitions. We aimed to develop and validate a short self-report measure of GI specific catastrophic cognitions. The GI-Cognitions Questionnaire (GI-Cog) was administered to a total of 291 participants, including 65 IBS patients, 114 Crohn’s disease patients, 22 patients with co-morbid Crohn’s and IBS and 90 healthy controls. The GI-Cog showed high internal consistency (α = .92) and good test re-test reliability (r = .87) as well as good factor structure. It discriminated between IBS patients, Crohn’s disease patients and normal controls, and explained unique variance in GI symptom severity. The GI-Cog is a short, easy-to-administer self-report measure of GI specific catastrophic cognitions that appears to be both reliable and valid and can be used in future research on vulnerability, treatment outcome and mediators of treatment efficacy.     

Streptomycin/Penicillin

Testosterone propionate was administered regularly to patients with microscopically proved carcinoma of the breast. No evidence of permanent control of the disease was obtained. It is emphasized that treatment with hormones of this type should not be substituted for established procedures such as surgical measures or radiation.     

The syndrome of abdominal aortic aneurysm rupturing into the gastrointestinal tract: Summary of the literature and case report

With the new case, which is reported in this paper, forty-one examples of rupture of an aneurysm of the abdominal aorta into some portion of the gastrointestinal tract are known to be available in the literature. In 71 per cent, rupture was into the third portion of the duodenum. The condition has been six times more frequent in men than in women. While the ages were widely distributed, the occurrence of eight cases between 27 and 32 years-of-age indicates the importance of this condition in relatively young patients. The resulting syndrome combines the features of abdominal aneurysm with those of profuse hemorrhage into the gastrointestinal tract. Hematemesis, often with abundant hemorrhage from the rectum, usually marks the onset of the terminal phase.     

Early indications of adhesive small bowel obstruction

The clinical symptoms and signs of small bowel obstruction are characteristic and are unlike any type of intra-abdominal disease. The colic is specific in character and different from other forms of abdominal colic. The x-ray is most valuable in confirming the diagnosis of small bowel obstruction, in locating the site of the obstruction and in determining to a large extent the nature of the obstruction.The function of the bowel distal to the obstruction is unimpaired and should adequate function take place it does not indicate the absence of obstruction.The urgency of immediate surgery is emphasized in strangulated obstruction in contrast to the feasibility of delaying surgery in advanced simple obstruction until physiological measures and intubation procedures can be adequately employed.