Influence of Microbial Profile and Antibiotic Delivery Method on Anatomical Bone Deformity after Chronic Osteomyelitis Surgery

Abstract

Background: Chronic osteomyelitis is a chronic bone infection that can result in the development of structural damage of the bone, recurrent surgery and postoperative deformity. The postoperative results could be influenced by the type of infecting organism and antibiotic delivery technique.

Objective: To determine the influence of microbial profile and antibiotic delivery method on anatomical bone deformity after chronic osteomyelitis surgery.

Methods: This observational study was conducted from January 2025 to June 2025, at the Margalla Institute of Health Sciences, Islamabad. Forty-nine of the 76 patients who had undergone surgery for chronic osteomyelitis were included. Demographic data, clinical characteristics, bone involved, culture results, microbial isolates, antibiotic administration route and postoperative outcomes were documented. The types of antibiotic delivery were classified as systemic antibiotics only, local antibiotics only, or combined systemic and local antibiotic therapy. The common final results were postoperative anatomical deformity of the bones, which included angulation, shortening, malalignment, joint stiffness and pathological fracture. Data were analyzed either by frequencies or percentages and using chi square test or logistic regression, and a value of p<0.05 was taken to be statistically significant.

Results: Culture positivity was observed in 63 patients (82.9%). Gram-positive organisms were most common, while multidrug-resistant organisms were identified in 24 patients (31.6%). Postoperative anatomical bone deformity occurred in 24 patients (31.6%). Deformity was more frequent among patients with polymicrobial infection, MRSA, and multidrug-resistant organisms. Patients treated with systemic antibiotics only had the highest deformity rate, while combined systemic and local antibiotic therapy was associated with a lower frequency of deformity. Multidrug-resistant infection, polymicrobial infection, MRSA, postoperative bone defect, and systemic antibiotics only were important predictors of deformity.

Conclusion: Postoperative anatomical bone deformity was observed in nearly one-third of patients after chronic osteomyelitis surgery. Resistant and polymicrobial infections increased the risk of deformity, whereas combined systemic and local antibiotic therapy was associated with better anatomical outcomes. Culture-guided treatment and appropriate local antibiotic delivery may help reduce deformity after surgery.