Comparative Effectiveness of Systemic, Local, and Combined Antibiotic Therapy on Anatomical Outcomes after Chronic Osteomyelitis Surgery

Abstract

ABSTRACT

Background: Chronic osteomyelitis is a long term bone infection which can lead to repeated infections, bone destruction, non-union and permanent deformity. The characteristics of the microbes and how the antibiotic was given could affect the recovery from infection and structural after surgery.

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

Methods: This was a prospective comparative study carried out in Rawal Institute of Health Sciences, Islamabad, between June 2025 and December 2025. Consecutive non-probability sampling was used to recruit 93 adult patients undergoing surgery for chronic osteomyelitis. Bone and deep tissue specimens were collected for culture and antimicrobial susceptibility test. Patients were classified as systemic antibiotics alone, local antibiotics alone or systemic and local antibiotics. The main outcome was anatomical bone deformity at surgery including angular deformity, limb shortening, malalignment, malunion, non-union and rotational deformity. Appropriate statistical tests and multivariable logistic regression were used to evaluate associations.

Results: The mean age of the participants was 41.8 ± 13.6 years, and 64.5% were male. Cultures were positive in 83.9% of cases, with Staphylococcus aureus being the most frequently isolated organism. Anatomical bone deformity occurred in 29 patients, giving an overall rate of 31.2%. Deformity was significantly more frequent in patients with polymicrobial infection, multidrug-resistant organisms, segmental bone defects and recurrent osteomyelitis. The deformity rate was 46.2% among patients receiving systemic antibiotics alone, 27.8% among those receiving local antibiotics and 16.7% among those receiving combined therapy. Multivariable analysis identified multidrug-resistant infection, polymicrobial infection, segmental bone loss and recurrence as independent predictors of deformity, while combined systemic and local antibiotic therapy was associated with reduced odds of deformity.

Conclusion: Microbial resistance, polymicrobial infection, bone loss and recurrent disease substantially increase the risk of anatomical deformity after chronic osteomyelitis surgery. Combined systemic and local antibiotic delivery may improve anatomical outcomes when used alongside adequate surgical debridement and reconstruction.