Reaming in treatment of non-unions in long bones: cytokine expression course as a tool for evaluation of non-union therapy.

Abstract

The analysis of peripheral serum cytokine expression patterns has been shown to be a possible method for demonstrating changes in bone metabolism. The aim of this study is to evaluate the effectiveness of this method within the treatment of long bone non-union with intramedullary reaming, a well-established non-union treatment concept. Three groups were added to this study: group one (G1) suffered from long bone non-unions, treated successfully with intramedullary reaming; group two (G2) consisted of long bone fractures with proper fracture healing; and group three (G3) included long bone fractures resulting in non-unions. We took blood samples on day 2, and after week 1, 4, 6, month 3 and 6 after initial treatment. Clinical and radiological follow-up were provided for 6months. We measured transforming growth factor ß-1 (TGFß-1), platelet-derived growth factor (PDGF-AB), and insulin like growth factor-1 (IGF-1) at all-time points. TGF-ß1 levels in G1 and G2 increased from day 2 to 6weeks after surgery. In general, G1 and G2 showed parallel TGF-ß1 expression patterns, and G3 had a significant peak during first week compared to G1 (p=0.023). PDGF peaked in G3 during first week after treatment, whereas G1 had its maximum after 4weeks and G2 after 6weeks. We were able to detect a significantly lower PDGF concentration at 3months in G1 compared to G3 (p=0.029). IGF-1 showed a peak concentration in G1 during the first 4weeks. Afterwards, concentration levels in both G1 and G2 were higher. Our study was able to show that the cytokine expression pattern in physiological bone healing is similar to that in successful non-union treatment with intramedullary reaming. Our results show that the effect of non-union therapy could be observed objectively by measuring cytokine expression patterns in peripheral blood even in a small group of patients.