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.     

Influenza B virus reinfection

Four outbreaks of influenza B infection occurred in Houston, Texas in the years 1976-1984. In the Houston Family Study, age-related infection and illness rates in the recent two epidemics resembled those reported previously. A total of 118 persons, including 35 children followed from birth, were followed longitudinally through this entire period and 331 persons were studied through at least two outbreaks. Fifty-nine (88%) of 67 children studied for four outbreaks were infected and 25% had a second infection; about half of the adults had one infection but only one of 51 was reinfected. Infection rates were proportionally lower for those followed through 2-3 outbreaks. Those with documented infection were protected decreasingly over time against reinfection and associated illness in subsequent epidemics. Such protection decreased in efficacy from 65% after 2-3 years, to 46% after 4-5 years, and to no protection after seven years.     

Peribursal fat plane of the shoulder: anatomic study and clinical experience

A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency.     

Acute intracranial hemorrhage secondary to thrombocytopenia: CT appearances unaffected by absence of clot retraction.

PURPOSETo describe the in vivo CT appearance of acute intracerebral blood clots formed from anemic platelet-depleted blood.METHODSThree patients with intracerebral hemorrhage secondary only to thrombocytopenia were examined with CT within 2 1/2 hours after the onset of clinical symptoms.RESULTSThere were no unusual CT features found in the intracerebral hemorrhages of patients with only thrombocytopenia. Specifically, a hyperdense zone(s) surrounded by areas of decreased density was identified.CONCLUSIONClot retraction (which cannot occur in patients with severe thrombocytopenia) is not necessary for the CT appearance of acute intracerebral hemorrhage.