Is it possible that a low dose of nicotine, the same as in just a few cigarettes, could have a positive impact on the healing of a broken bone? Dr Rami Kallala from Leeds Teaching Hospital (Great Britain) answered this question with a conditional “Yes” at the 13th Congress of the European Federation of National Associations of Orthopaedics and Traumatology (EFORT) in Berlin, where 7,000 experts are currently gathering to discuss the latest findings in their field.
Largely negative results for animals
Matching results were obtained that nicotine had extensive effects, both positive and negative, on bones in humans and in animals. The results in animals were predominantly negative. For example, nicotine was shown to inhibit the synthesis of certain types of collagen and thus to have a deleterious effect on fracture healing. Nicotine was also shown to have a negative effect on bone structure and to lower the levels of vitamin D, a substance needed to store calcium in bone tissue. Dr Kallala: “With these results, you should keep in mind that the nicotine concentration in most animal studies is much higher than the level you would find even in heavy smokers. In some animal studies the opposite was shown to be the case, namely how moderate doses of nicotine were able to slow down or even reverse the progress of osteoporosis.”
Stimulating effect of nicotine on bone metabolism
Positive impacts were also observed in in vitro studies with human cells. At low concentrations, nicotine was shown to stimulate cell division and bone metabolism. Specifically, it stimulates the osteoblasts MG-63 and SAOS-2, cells similar to those responsible for bone formation. Nicotine also increases the expression of c-fos and the synthesis of protein and collagen. These processes are responsible for bone build-up and remodeling. At higher concentrations, the stimulatory effects turn negative. Many studies show that higher concentrations of nicotine have an inhibitory or even toxic effect on bone cells. “The positive findings until now are meaningful only conditionally. This is mainly due to inherent limitations to studying solely the effect of nicotine on bone healing in the clinical setting. To find out how nicotine affects bone healing, further basic research and clinical studies should be conducted. Only then could conclusions be drawn for clinical practice,” Dr Kallala said.
Smokers less satisfied after knee surgery
Dr Cronan Kerin and his team from Aintree University Hospital Liverpool, Great Britain, also presented findings at the EFORT Congress in Berlin. The expert determined that smokers were less satisfied with the outcome of treatment following knee surgery. Specifically, he examined the medium-term success of therapy in microfracture surgeries. For this study, his team asked patients after a microfracture if they were satisfied with the outcome of treatment in general and requested them to assess the functional outcome, particularly, for example, whether the knee could be bent entirely. A total of 196 patients responded.
Smoking should be given up prior to surgery
The results show that a total of 72% of the patients were satisfied with the outcome. Dr Kerin: “Patient satisfaction depended mainly on one factor, namely whether or not the patient smoked.” Only 54% of the smokers were satisfied with the outcome of therapy whereas 76% of the non-smokers were. One in three smokers (34%) was definitely dissatisfied whereas only one in seven of the non-smokers was (15%). Dr Kerin: “My conclusion is that smoking unfavourably affects the outcome of microfracture. This is an important finding for counselling. Surgeons should advise their patients in the future to stop smoking undergoing surgery.”
During the last decade, microfracture of the knee has emerged as a good technique for treating cartilage lesions of the knee. It is a relatively inexpensive and technically straightforward procedure. The bone is drilled in such a way that blood vessels sprout into the remaining cartilage. This is how stem cells reach the affected joint surface and form stabile and resilient replacement cartilage.
The European Federation of National Associations of Orthopaedics and Traumatology, EFORT, is the umbrella organisation linking Europe´s national orthopaedic societies. EFORT was founded in 1991 in the Italian Marentino. Today it has 42 national member societies from 43 member countries and six associate scientific members.
EFORT is a non-profit organisation. The participating societies aim at promoting the exchange of scientific knowledge and experience in the prevention and treatment of diseases and injuries of the musculoskeletal system. EFORT organises European Congresses, seminars, courses, forums and conferences. It also initiates and supports basic and clinical research.
Source: EFORT Abstract 4237: Effects of knee compartment, concomitant surgery and smoking on medium term outcome of microfracture; EFORT Abstract 5509: The impact of nicotine on bone and fracture healing: A systematic review.