Abstract
This is an ongoing retrospective study of 35 children treated from 1986 to 2001 for chronic osteomyelitis following acute haematogenous osteomyelitis. The purpose was to validate the use of a modified Cierny classification to predict behaviour, to assess the timing of sequestrectomy in relation to involucrum formation, and to evaluate the results of dealing with the resultant defect by conventional methods of bone grafting.
The mean age of the patients was 7 years (1 to 12). All except 18, who were treated within five days of acute onset, were delayed presentations or transfers. In 14 children the tibia was involved, in 13 the femur, in five the humerus and in three the fibula. Monthly radiographs were taken and the size and location of the sequestrum and involucrum was documented.
Our classification represents the size and location of the sequestrum. We divided the patients into cortical (one), medullary (three), corticomedullary (12) and structural (19) types. Fractures occurred in all the structural types, as well as in five of the 12 corticomedullary types. A sequestrum was apparent at a mean of 2.4 months (1 to 3). The mean length of the sequestrum at diagnosis was 8.5 cm and at surgery 5.8 cm, suggesting partial resorption. Involucrum formed in 69% of patients at a mean of 1.9 months (1 to 3) after sequestrum. In 31% of patients no involucrum formed from 4 to 12 months after surgery. This suggests that involucrum formation depends on viable periosteum and not on the sequestrum, and in the absence of involucrum early rather than late sequestrectomy is warranted.
The resultant incomplete bone defects in the corticomedullary type ranged from 1 cm to 15 cm, but had an intact cortical bed on one or more sides. These and complete defects of less than 6 cm in the structural type united after autogenous cancellous bone grafting, with or without an exoskeleton. Four structural defects greater than 6 cm united after fibular strut grafting (humerus) or bone grafting from fibula to tibia via a posterolateral approach (tibia).
Patients were followed up both clinically and radiologically for a mean of 2.9 years. Twenty patients (57%) had an excellent result and 15 (43%) a good result.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at PO Box 47363, Parklands, Johannesburg 2121, South Africa.
