Purpose of the study: We have performed a prospective study in 54 patients with suspected osteoarticular deep infection. The purpose of the study was to compare notch needle-biopsy versus simple punction in term of bacteriological efficiency.
Material and methods: Among 54 patients (32 males, 22 females), 16 cases of deep infections were proven. There was 29 hips, 17 knees, 6 ankles, 2 elbows and 1 shoulder. Each patient was investigated with simple punction and notch needle-biopsy. Diagnostic value of both methods were evaluated by comparison with results of surgical prelevement which was the gold standard for evaluating both tests. The study was made using usual diagnostic test criteria: sensitivity, specificity, positive predictive value, negative predictive value and also likelihood ratio method.
Results: Sensibility for the simple punction was 31.25 per cent and sensibility for notch needle-biopsy was 69 per cent. Specificity for simple punction was 97 per cent but for notch needle-biopsy it was 100 per cent. Positive predictive value was respectively 83.33 per cent for simple punction and 100 per cent for notch needle-biopsy. Negative predictive value was 0.71 per cent for simple punction and 0.31 per cent for notch needle-biopsy. Likelihood ratios for simple punction was 11.87 and likelihood ratios for notch needle-biopsy was infinite.
Discussion: Sensibility for notch needle-biopsy of 69 per cent is two time superior to sensibility of simple punction. Notch needle-biopsy had no false positive. It is a completely specific test. Methodology was valuable because all patients who had negative result of non invasive test had no preoperative antibiotherapy, and underwent surgery for bacteriological diagnostic only.
Conclusion: Notch needle-biopsy is always superior to simple punction. This study leads us to modify our practice. From now on we will never use again simple punction but we will only perform notch needle-biopsy which diagnostical efficiency is superior.