Acute hematogenous osteomyelitis and septic arthritis are pyogenic infections of bone and joint, respectively. At the youngest age, they usually occur at the same time--hence the common name "osteoarthritis". When it comes to neonates, osteoarthritis is an infrequent finding, but it can give a permanent disability and can be even fatal unless early recognized and adequately and promptly treated. An early diagnosis is rather challenging because the signs and symptoms of this disease are subtle and/or nonspecific. The therapy involves a combination of intravenous antimicrobial therapy in high doses and of sufficient duration, with a mandatory decompression of affected joint by needle aspiration or artrhrotomy. The aim of this paper is to present two premature newborns with rare localization of osteoarthritis - the humerus and shoulder joint, as well as to point to the modern diagnostic and therapeutic approach to this disease.

Osteoid osteoma is a small benign bone lesion. It generally affects children and young adults. Traditional treatment of osteoid osteoma includes excision either by wide resection, or by the removal of the nidus using curettes and burrs after opening the overlying cortex. Newly developed techniques involve percutaneous ablation of the tumor by computed tomography-guided core-drill excision and destruction of the nidus by thermocoagulation. Fluoroscopic guided percutaneous extirpation and drilling resection procedures have been performed at the Institute for Health Care of Children and Youth, Pediatric Surgery Clinic in Novi Sad, Serbia. Some modifications in the methods were made and implemented, which resulted in an excellent cost-benefit ratio, shorter period of hospitalization, and faster recovery. The aim of this paper is to present the experience gained in the treatment of osteoid osteomas in the last 5 years at the Pediatric Surgery Clinic in Novi Sad and to describe the modifications to the percutaneous biopsy technique of osteoid osteoma that have been implemented.

Arthroscopy has developed as one of the branches of former cystoscopy. During the past 200 years a few people have made invaluable contributions to development of arthroscopy (Bozzini, Takagi, Watanabe...) After the World War II scientific and technological progress was so fast that arthroscopy proved to be a valuable tool in orthopedics, not only as a diagnostic, but also as a therapeutic procedure.

The ultrasonography should be the method of choice in painful hip differentiation regardless of the age. The ultrasonography can replace radiography safely in the primary diagnostic procedure as well as through the control examination.

In young children the standard treatment was hip spica cast after traction. Intramedullar elastic nailing is a modern trend accepted as standard in our approach to femur fracture treatment in children.