We studied the effects of insulin-like growth factor I on Achilles tendon healing in a rat model. Rats were randomized into groups of six each: sham surgery, transection alone, and transection plus growth factor. Postoperatively, rats treated with growth factor had a significantly smaller maximum functional deficit and a decreased time to functional recovery than rats in the untreated groups. Biomechanical testing revealed no significant differences in the measured parameters between the treated and the untreated groups after transection. To study the mechanism of action, six additional animals received an Achilles tendon injection of the inflammatory agent carrageenan alone and six received carrageenan plus growth factor. Rats treated with growth factor did not show the inflammation-induced functional deficit experienced by the control rats. Spectrometric myeloperoxidase assays on the remaining eight rats after Achilles tendon transection demonstrated no significant difference between the untreated and the growth factor-treated groups, indicating a mechanism other than neutrophil recruitment by which the growth factor limits inflammation. Histologic studies were performed on carrageenan-injected rats at postinjection day 2 and on surgically treated rats at postoperative day 15. No gross histologic differences were seen between untreated and growth factortreated groups. This study demonstrated that via a possible antiinflammatory mechanism, insulin-like growth factor I reduces maximum functional deficit and accelerates recovery after Achilles tendon injury.

A recent paradigm shift in microbiology affects orthopaedic surgery and most other medical and dental disciplines because more than 65% of bacterial infections treated by clinicians in the developed world are now known to be caused by organisms growing in biofilms. These slime-enclosed communities of bacteria are inherently resistant to host defenses and to conventional antibacterial therapy, and these device-related and other chronic bacterial infections are unaffected by the vaccines and antibiotics that have virtually eliminated acute infections caused by planktonic (floating) bacteria. We examine the lessons that can be learned, within this biofilm paradigm, by the study of problems (e.g. non-culturability) shared by all biofilm infections and by the study of new therapeutic options aimed specifically at sessile bacteria in biofilms. Orthopaedic surgery has deduced some of the therapeutic strategies based on assiduous attention to patient outcomes, but much can still be learned by attention to modern research in related disciplines in medicine and dentistry. These perceptions will lead to practical improvements in the detection, management, and treatment of infections in orthopaedic surgery.

The detection and identification of bacteria present in natural and industrial ecosystems is now entirely based on molecular systems that detect microbial RNA or DNA. Culture methods were abandoned, in the 1980s, because direct observations showed that <1% of the bacteria in these systems grew on laboratory media. Culture methods comprise the backbone of the Food and Drug Administration-approved diagnostic systems used in hospital laboratories, with some molecular methods being approved for the detection of specific pathogens that are difficult to grow in vitro. In several medical specialties, the reaction to negative cultures in cases in which overt signs of infection clearly exist has produced a spreading skepticism concerning the sensitivity and accuracy of traditional culture methods. We summarize evidence from the field of orthopedic surgery, and from other medical specialties, that support the contention that culture techniques are especially insensitive and inaccurate in the detection of chronic biofilm infections. We examine the plethora of molecular techniques that could replace cultures in the diagnosis of bacterial diseases, and we identify the new Ibis technique that is based on base ratios (not base sequences), as the molecular system most likely to fulfill the requirements of routine diagnosis in orthopedic surgery.

Medial opening-wedge high tibial osteotomy produces good results in the midterm. After the osteotomy, a more normal appearing weightbearing pattern with double peaks was seen. The adduction moment significantly decreased, resulting in less contact pressure through the medial degenerative compartment of the knee. The authors recommend medial opening-wedge high tibial osteotomy for young patients with varus alignment and medial compartment arthritis to allow this patient population to remain highly active and delay progression to total knee arthroplasty without activity restrictions.

Most chronic infectious disease processes associated with bacteria are characterized by the formation of a biofilm which provides for bacterial attachment to the host tissue or implanted medical device. The biofilm protects the bacteria from the host’s adaptive immune response, as well as predation by phagocytic cells. However, the most insidious aspect of biofilm biology from the host’s point of view is that the biofilm provides an ideal setting for bacterial horizontal gene transfer (HGT). HGT provides for large-scale genome content changes in situ during the chronic infectious process. Obviously, for HGT processes to result in the reassortment of alleles and genes among bacterial strains the infection must be polyclonal (polymicrobial) in nature. In this review we marshal the evidence that all of the factors are present in biofilm infections to support HGT which results in the ongoing production of novel strains with unique combinations of genic characters and that the continual production of large numbers of novel, but related bacterial strains leads to persistence. This concept of an infecting population of bacteria undergoing mutagenesis to produce a ‘cloud’ of similar strains to confuse and overwhelm the host’s immune system parallels genetic diversity stratagies employed by viral and parasitic pathogens.