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Incidence of nonunion after open tibia fractures in Malawi : associated factors and Radiographic Union Score for
Alexander Thomas Schade1,2,3,4, Richard Dimock3,5, Thomas Mendes da Costa6
1Malawi-Liverpool-Wellcome Trust, Blantyre, Malawi.
Aims:
Open tibia fractures are a common and severe injury in low-income countries (LICs), and worsened by fracture-related infection (FRI). The Radiographic Union Score for Tibial fractures (RUST) is widely used to assess fracture healing, but its reliability and factors associated with nonunion in LICs remain unclear.
Methods:
We conducted a multicentre prospective cohort study in six hospitals across Malawi, enrolling 287 adults with open tibia fractures between February 2021 and March 2022. Participants underwent standardized clinical and radiological follow-up at three, six, and 12 months post-injury. Fracture union at follow-up was assessed independently by two reviewers using the RUST score. Patient function was measured using the Short Musculoskeletal Function Assessment (SMFA) score. Multilevel regression models examined associations between RUST scores, functional outcomes, baseline factors, and treatment methods.
Results:
Participants had a median age of 34 years (IQR 25 to 44), and 84% (248/287) were male. Overall, 45/177 (25.4%) of participants with open tibia fractures had a nonunion at one year, with 34.2% (13/38) with FRI having nonunion compared with 15.4% (20/130) no FRI (p = 0.001). After adjusting for other variables, compared with external fixation, intramedullary nailing (odds ratio (OR) 1.35, 95% credible interval (CrI) 0.98 to 1.93) and plaster of Paris (POP) fixation (OR 2.05, 95% CrI 1.29 to 3.64) were associated with higher RUST scores. Each one-point increase in RUST score was associated with -4.1 (95% CrI -6.2 to -2.1) SMFA score, reflecting better function. Interobserver reliability of RUST was moderate (ICC 0.51, 95% CI 0.28 to 0.61), despite 74% of radiographs being of suboptimal quality at one year.
Conclusion:
Nonunion is common after open tibia fracture in Malawi, particularly with external fixation and FRI. The RUST score is reliable and correlates with patient function in LIC settings, even with variable radiograph quality. Poor function should prompt a careful assessment for nonunion and consideration of intervention where appropriate.