Bacteria, viruses, and fungi are all capable of infecting a joint. These tiny organisms invade and inflame the synovial membrane of the joint. Joint destruction with arthritis may be a local response to this infection. This condition is referred to as bacterial, infectious or septic arthritis.
Acute septic arthritis in children can be present at birth. Or it can develop in the early weeks-to-months after birth. Treatment is based on X-ray findings. The hips are classified based on radiographic appearance.
The most commonly used classification scheme was published by Dr. Choi and associates in 1990. This method places the hips in one of four types. There are eight subtypes. But the Choi classification doesn’t work well in young children. For this reason, Drs. E. Forlin and C. Milani from Brazil have devised a simpler model of radiographic classification.
The new classification has two groups. Grade 1 means the hip is well-placed in the hip socket. If there is a femoral head present, it is labeled Grade 1A. If the femoral head is absent at birth, it is classified as Grade 1B. Hips in the second group (grade 2) are dislocated. Grade 2A means the femoral head is intact. Grade 2B tells us the femoral head is missing.
With this method, there are only two groups and two subgroups. The classification is first based on whether or not the femoral head or neck was in or out of the acetabulum (hip socket). The subgroups depended on whether or not the femoral head was present or absent.
Using this grading system, the medical records and X-rays were reviewed for all children with septic arthritis of the hip. The children were treated at the hospital between 1985 and 1997. The children were first treated at other medical centers during the acute phase. Treatment at the authors’ hospital was for complications later.
After using the new classification method, results were compared with the Choi classification model. Independent pediatric orthopedic surgeons were asked to use both systems to classify the hips of 37 children with hip septic arthritis (41 hips total). The authors compared their results with results reported by Dr. Choi in another publication.
At the same time, a separate clinicalclassification was made. This was based on 1) whether or not the joint was stable, 2) range of motion, and 3) presence of pain. Unstable meant the hip was dislocated. An unsatisfactory result occurred when there was instability, less than 50 degrees of hip flexion or loss of hip extension, or a painful hip during daily activities.
The results of all comparisons showed no differences between the Choi method and this new method. The advantage of this new classification is that it is simpler and more appropriate for use with children. It relies on the assessment of two factors: instability and the presence of the femoral head.
As might be expected, type 1 hips had a better chance for a satisfactory result. The earlier the treatment, the better the prognosis. Delays of more than four days led to complications and poorer prognosis.
The authors present the procedures they used to correct the changes that occurred within the joint after infection. The shelf procedure and proximal femoral valgus osteotomy were both mentioned.
Reconstruction with osteotomy and acetabuloplasty were also discussed. Osteotomy refers to cutting out a wedge- or pie-shaped piece of bone. The bone is used to extend the shelf over the femoral head. This forms a deeper, more stable socket. Acetabuloplasty accomplishes the same thing using bone graft from some other source such as a bone bank.
In summary, the two-group/two subgroup classification scheme is simple and reliable. It helps the surgeon decide the timing and type of treatment needed. It may also be useful for making a long-term prognosis.