Anti-Bacterial Agents/therapeutic use; Clostridium Infections/prevention & control; Clostridium/isolation & purification; Osteomyelitis/drug therapy; Osteomyelitis/prevention & control; Tibia/pathology; Tibial Fractures/therapy; Administration, Oral; Cefuroxime/therapeutic use; Chronic Disease; Clindamycin/therapeutic use; Clostridium/drug effects; Clostridium/genetics; Clostridium Infections/diagnosis; Clostridium Infections/drug therapy; Clostridium Infections/microbiology; Drug Therapy, Combination; Germany; Humans; Infusions, Intravenous; Magnetic Resonance Imaging; Male; Metronidazole/therapeutic use; Middle Aged; Osteomyelitis/diagnosis; Osteomyelitis/microbiology; Radiography; Recurrence; Tibia/diagnostic imaging; Tibia/microbiology; Tibial Fractures/diagnostic imaging; Tibial Fractures/microbiology; Tibial Fractures/pathology