Patellofemoral joint arthroplasty: patient selection,surgical technique and outcomes

Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.     

Age-dependent Responses to Thermal Hyperalgesia and Mechanical Allodynia in a Rat Model of Acute Postoperative Pain

Background: Developmental differences in short- and long-term responses to pain, especially surgical pain, have received minimal attention. The purpose of the present study was to examine postoperative responses in rats of developmental ages paralleling the infant to young adult human.

Methods: The withdrawal threshold to von Frey filament testing and withdrawal latency to hind-paw radiant heating were determined before and for various times after hind-paw incision in rats 2, 4, and 16 weeks of age. Control rats of these ages were observed serially without surgery.

Results: In control animals, younger rats were more sensitive to mechanical stimulation and less sensitive to thermal stimulation. Paw incision resulted in similar changes to both types of stimulation in all age groups, peaking 4 h after surgery. However, the return to normal sensitivity to mechanical stimulation, as measured by return of threshold to 80% of normal, occurred more quickly in 2-week-old than in 4- and 16-week-old animals. In contrast, there was no age difference for time to return to normal sensitivity to thermal stimulation after surgery.     

Interactions of iron deficiency and exercise training relative to tissue norepinephrine turnover, triiodothyronine production and metabolic rate in rats

The interactions of iron deficiency and exercise training relative to resting metabolic rate (RMR), tissue norepinephrine (NE) turnover and triiodothyronine (T3) production were examined in male Sprague-Dawley rats. Animals were assigned to iron-deficient (ID) or control (CN) diets and to sedentary (SD) or treadmill-exercise (EX) groups for 6 or 12 wk. Iron-deficient animals (hemoglobin 7.2 +/- 0.2 g 100 mL-1) had a 17% higher RMR and had slower growth rates than CN animals. Exercise training affected growth but not RMR in iron deficiency. Oxygen consumption (Vo2) following pharmacologic injection of norepinephrine was similar in both iron-deficient and exercised groups despite a 35% lower maximal exercise Vo2 in trained iron-deficient rats. NE turnover was lower in heart (55%) and liver (80%) of iron-deficient animals relative to controls. Trained iron-deficient animals had lower NE turnover in interscapular brown adipose tissue (IBAT) than sedentary iron-deficient animals; however, training did not alter NE turnover in control animals. In vitro liver and IBAT T3 production was similar in all groups except for lower activities (40%) in 6-wk iron-deficient, exercised animals. The significant effect of exercise on the growth attenuation of iron-deficient, exercised animals is thus not explained by increased IBAT metabolic activity or a generalized sympathetic nervous system activation. Decreased T3 production during periods of rapid growth and lean body mass development, however, may be important in exercised, iron-deficient animals.     

Mandibular-facial reconstruction with segmentally split serratus anterior composite flaps

Oncologic or traumatic head and neck defects with missing mandible, facial skin, and oral mucosa are especially well suited to reconstruction with a composite tissue unit, based on the subscapular-thoracodorsal vessels, that carries any combination of skin, bone, and muscle to restore vascularized skeletal structures, oral lining, and skin cover. The subscapular-thoracodorsal vascular pedicles supply segmentally split units of the lower serratus muscle and ribs on which it originates. Also, one or two skin paddles for cover and lining flaps are carried either by the cutaneous scapular and parascapular branches of the circumflex scapular vessels or by surgically split segments of the latissimus dorsi musculocutaneous flap. The composite flap can be designed in a variety of combinations to meet recipient defect needs and allow retained innervated segments of the component muscles in situ for preservation of donor motor function. The common subscapular-thoracodorsal vascular pedicle can be transferred either as a microvascular free flap or by pedicle transposition through a subpectoral-subplatysmal tunnel to the mandibular-facial defect. This versatile reconstructive unit illustrates many of the refinements of contemporary flap reconstructions.     

Anaphylaxis following ingestion of a psyllium-containing cereal

Recently, psyllium hydrophilic mucilloid, a bulk-forming laxative, has been added to breakfast cereals for cholesterol-lowering effects. We report a case of a 60-year-old woman with no prior history of psyllium ingestion who developed anaphylactic symptoms after eating a psyllium-containing cereal. Her only previous exposure was dispensing a psyllium-containing laxative as a nurse. Immunoglobulin E-mediated sensitization was documented by skin testing and basophil histamine release. The literature is reviewed regarding allergic reactions to psyllium. Health care workers and pharmaceutical workers handling psyllium may be at increased risk due to sensitization from inhalation. Physicians and consumers should be aware of potential serious reactions from eating psyllium-containing cereals even without prior history of ingestion of psyllium.