Open fractures can be defined as fractures which communicate with the outside environment through a soft tissue wound. The majority of open fractures are those of the long bones, while most occur in the lower extremity and particularly the tibia. (1) Open tibial diaphyseal fractures are severe injuries that can lead to significant long-term disability if not treated appropriately. Such fractures often result from high-energy trauma, such as motor vehicle accidents or falls from a height.(2) Improper treatment can lead to bone infection, osteonecrosis, bone nonunion, and amputation.(3) Historically, it has been suggested that timely surgical debridement can reduce the various complications occurring after treatment. Gustilo and Anderson stated that ‘adequate debridement is the single most important factor in the attainment of a good result in the treatment of an open fracture’.(4) Despite the rapid development of modern orthopedic treatment techniques, postoperative complications of open tibial fractures are still high. The most common complications are infection, nonunion and amputation, which seriously affects the quality of life and brings a huge economic burden to individuals and the health system.(5) Currently, there are different opinions on the treatment of open tibial fracture. Therefore, how to effectively managing open tibial fracture has always been a difficult problem for orthopedic trauma surgeons.(6) Fixation of tibia fractures with bridge plating has demonstrated excellent results as it can restore the anatomic structure of the bone. But plating requires exposure of the bone surface and extensive soft tissue dissection, thus carrying the risks of bleeding, infection, soft-tissue healing problems, and hardware-related complications as well as it destroys the periosteum which is very important for blood supply to the fractured area. Although problems related to soft-tissue dissection and healing can be largely sorted out with a uniplanar external fixation, it bears the risks of malunion, non-union, and pin-tract infections.(7) In one study Incidence of pin tract infection was 87.7% after uniplanar external fixation of open fracture.(8)

The rationale of this study is to determine frequency of pin track infection in open tibia fracture managed with uniplanar external fixation. The frequency of pin track infections in open tibia fractures managed with uniplanar external fixation remains inadequately characterized in the literature. Understanding the incidence and associated risk factors for these infections is critical for several reasons including patients’ safety, resource allocation and gaping future research. Pin track infections can lead to significant morbidity, including prolonged hospitalization, increased pain, and the need for additional surgeries. By assessing the frequency of these infections, we can enhance patient care and minimize complications. The management of complications such as pin track infections can be resource-intensive. By understanding the prevalence and risk factors, healthcare systems can better allocate resources, improving efficiency and reducing costs associated with complication management. A clearer understanding of the frequency of pin track infections could pave the way for further research into preventive measures, alternative fixation methods, and better surgical practices.

OBJECTIVE:

To determine frequency and associated risk factors of pin track infection in open tibia fracture managed with uniplanar external fixation in Ayub Teaching Hospital.

OPERATIONAL DIFINITIONS:

Open tibia fracture: It will be defined as tibial fractures which communicate with the outside environment through a soft tissue wound visible on physical examination.

Chicketts-Otterburn classification

A simplified form of Chicketts-Otterburn classification was used for grading. This is shown below.

Table 1: Grading of Pin Tract Infection.

The Gustilo–Anderson classification was used to grade the severity of open fractures based on wound size, soft-tissue          damage, and contamination risk, as follow

Table 2: Gustilo–Anderson classification

Study Design: Cross sectional study Study Setting: Department of Orthopedics, Ayub Teaching Hospital Abbottabad Study Duration: Six months after the CPSP approval of synopsis , from 24th april 2025 to 24th October 2025 Sampling Technique: Non probability consecutive sampling Sample Size: Sample size was calculated using WHO calculator keeping 95% confidence level, 7% absolute precision, and 87.7% previously reported frequency of pin tract infection after uniplanar external fixation in open fracture. Sample size of 85 patients. Selection criterion: Inclusion Criteria: • All the Patients aged 18 to 60 years who had open tibia fracture and presenting within 7 days of fracture and managed with uniplanar external fixation at Ayub Teaching Hospital, Abbottabad. Exclusion Criteria: • Fractures with intra-articular extension, bilateral tibial fractures, open fractures with bone loss, associated pelvic and acetabulum fractures, ipsilateral open femur fracture requiring external fixator Data collection procedure: After approval from hospital ethical board and CPSP, patients fulfilling the selection criteria was enrolled from orthopedic indoor of Ayub Teaching Hospital. A written informed consent was taken after explaining the purpose, benefits and risk of study. Demographic data including age, gender, duration of fracture, residence, profession, educational level and socioeconomic status and comorbidities like hypertension, were noted. Complete history was taken and physical examination was done. All patients undergone uniplanar external fixation by consultant orthopedic surgeon having at least five years of post-fellowship experience. Patients were followed till 28 days to note pin tract infection as per operational definition. Data on the presence and severity of pin tract infection were recorded using a simplified version of the Chicketts–Otterburn classification (Table 1). For microbiological assessment, the pin site area was cleaned with normal saline to remove debris and necrotic tissue, followed by drying with sterile gauze. After changing to sterile gloves, a pus swab was taken by pressing it between the pin and surrounding soft tissue to collect exudate. The swab was placed in Amies transport medium and sent to the laboratory within one hour. Samples were incubated at 37 °C for 16–18 hours and cultured under aerobic (Sheep Blood Agar, MacConkey agar) and anaerobic (Wilkins Chalgren Amikacin Agar) conditions. Positive cultures were tested for antibiotic sensitivity. All patients underwent a follow-up X-ray at six weeks, while those with major pin tract infection (Chicketts grade ≥ 4) had immediate radiographs to assess for bone involvement or pin loosening. Data was entered in specially designed proforma. Data analysis procedure: Data was entered and analyzed by using SPSS version 22.0. Mean and standard deviation was calculated for quantitative variables like age and duration of fracture. Shapiro–Wilk test was used to check normal distribution of data, in case of non-normal distribution median (IQR) was calculated. Frequency and percentage was calculated for categorical variables like gender, residence, profession, educational level, socioeconomic status and pin tract infection. Effect modifiers like age, gender, duration of fracture residence, profession, educational level and socioeconomic status were addressed through stratification of data. Post stratification chi square was applied for (Fisher’s test exact in cases n≤5). P value ≤0.05 will be taken as statistically significant.

A total of 85 patients with open tibial fractures managed with uniplanar external fixation were included in the study. The mean age of the patients was 40.5± 11.35 years (range: 18–60 years). Among them, 62 (72.9%) were males and 23 (27.1%) were females, giving a male-to-female ratio of 2.7:1.

Table 1. Distribution of Comorbidities and Smoking Status Among Study Participants (n = 85)

Table 2. Distribution of Education Level Among Study Participants (n = 85)

Table 3. Socioeconomic Status of Study Participants (n = 85)

Fracture Characteristics

Table 4. Distribution of Gustilo–Anderson Fracture Grades Among Study Participants (n = 85)

Table 5. Frequency and Grading of Pin Tract Infection

Overall, 48 (56.5%) patients developed pin tract infection, while 37 (43.5%) remained infection-free.

Table 6. Association Between Risk Factors and Pin Tract Infection (n = 85)

Microbiological Findings

Among 85 patients, 48 (56.5%) showed positive microbial growth. Staphylococcus aureus was the most frequently isolated organism (62.5%), followed by Pseudomonas aeruginosa (18.8%), E. Coli (12.5%), and Proteus species (6.3%).The majority were sensitive to amikacin, clindamycin, and ciprofloxacin, while resistance was noted to ampicillin and first-generation cephalosporins.

In the present study, the overall incidence of pin tract infection was 56.5%, which is comparatively higher than the 27.3% reported by Albushtra et al. (2024) in their retrospective series of 110 patients with complex tibial diaphyseal fractures managed with unilateral external fixation as the definitive treatment in a resource-limited setting.(9) The difference may be attributed to variations in patient characteristics, fracture severity distribution, postoperative care protocols, and socioeconomic factors. Whereas Albushtra et al. included a larger sample size with standardized postoperative pin care, the current study population had a greater proportion of Gustilo type III injuries (>60%) and lower socioeconomic status, both of which are established risk factors for higher infection rates. Some contemporary series report lower rates (around 20–30%) when prophylactic protocols, shorter fixation times, and standardized pin-care are used. For example, a 2024 single-centre series reported a PTI rate ≈27% using a standardized protocol. (10) Other studies (especially from resource-limited settings or where external fixation is used as definitive treatment for severe open fractures) report rates comparable to our studies (40–70%). Reviews of external fixation in developing countries emphasise higher complication burdens where socioeconomic and logistical challenges exist.(11) The wide variation in published incidence stresses the need to report clear definitions in terms of Chicketts–Otterburn grading and to state whether superficial PTI only or deep osteomyelitis were included. In the present study, the mean age of patients was 40.5 years, with a clear male predominance, aligning with the demographic pattern commonly reported for tibial shaft fractures, where young, working-age males are more frequently affected due to road traffic accidents. Similar age distribution and male preponderance have been observed across multiple recent studies. Furthermore, in our univariate analysis, age (p = 0.840) showed no statistically significant association, whereas sex (p = 0.048) showed a statistically significant association with the development of pin tract infection (PTI) in females, which is inconsistent with previous literature indicating that demographic factors such as age and sex are not independent predictors of PTI once comorbidities and injury severity are taken into account.(12) In the current study, 81.8% (9 out of 11) of diabetic patients developed infection, compared to 52.7% (39 out of 74) of non-diabetic patients, although a higher rate of pin tract infection was observed among diabetic patients, the association was not statistically significant (p = 0.069). The trend suggests diabetes might be a potential risk factor, and a larger sample size could clarify this relationship. This finding supports the well-established understanding that diabetes is a major host-related risk factor for infectious complications following open fractures and external fixation. Several recent studies and retrospective analyses have similarly identified diabetes as an independent predictor for both superficial and deep infections after fracture management. In agreement with our results, Ukai et al. (2020) also reported diabetes as a significant host factor associated with deep infection, particularly in patients with Gustilo type-III fractures.(12) CKD and decompensated liver disease were uncommon in our cohort and not statistically associated with PTI; published data are sparse and mixed for these less frequent comorbidities. Most series emphasize diabetes and smoking as consistent comorbidity risk factors; less frequent conditions require larger samples to test associations reliably. (12) Clinical implication: careful glycaemic control, early optimisation and perhaps lower threshold for close surveillance or earlier pin removal should be considered in diabetic patients. In our study, PTI was more frequent among patients who were smoking (72.7%) compared to those not smoking (50.8%), although this difference did not reach statistical significance (p = 0.074). This trend aligns with previous literature that identifies smoking as a potential risk factor for wound and fixation-related infections, as well as for delayed or impaired healing. However, the reported effect size in various studies has been inconsistent, often influenced by confounding factors such as injury severity and associated comorbidities. Recent retrospective cohorts similarly note smoking as an adverse factor, with some demonstrating statistically significant associations, while others lose significance after multivariable adjustment.(12) In the present study, pin tract infection (PTI) was significantly more common among illiterate patients and those belonging to a low socioeconomic group (p = 0.001 and p = 0.001, respectively). These findings are consistent with current literature highlighting the influence of educational and socioeconomic factors on postoperative outcomes following external fixation. Lower education levels and limited socioeconomic resources have been associated with delayed presentation, inadequate adherence to pin-site care protocols, poor hygiene, and limited access to follow-up or wound care materials—all contributing to higher infection rates. Several regional and international studies have similarly demonstrated that socioeconomic disadvantage correlates with increased complication rates, particularly in settings where external fixation serves as a definitive treatment. Furthermore, interventional studies focusing on patient education and structured pin-care programs have shown a reduction in PTI incidence, reinforcing the causal relationship between socioeconomic and educational status and infection risk.(13) In the present study, a significant association was observed between the Gustilo–Anderson fracture grade and the development of pin tract infection (p < 0.001). The frequency of infection increased progressively with higher grades of open fractures. Patients with Grade I fractures had the lowest infection rate (12.9%), while those with Grade IIIB and IIIC fractures demonstrated universal infection (100%). This finding indicates that the severity of soft tissue injury and the extent of contamination play a crucial role in the risk of pin tract infection. This mirrors consistent data in the last five years: multiple contemporary studies show that higher Gustilo grade (reflecting greater soft-tissue damage and contamination) is one of the strongest predictors of both superficial and deep infections after open tibial fracture fixation. Ukai et al. (2020) and several subsequent reports emphasise that type III injuries, particularly IIIB, carry substantially higher infectious complication rates.(12) This implicates that for Gustilo III fractures, do consider aggressive soft-tissue management (early flap coverage when indicated), multidisciplinary orthoplastic care, and stricter pin surveillance. In our cohort, Staphylococcus aureus was the most frequently isolated pathogen (62.5%), followed by Pseudomonas, E. coli, and Proteus species. This predominance of staphylococci including both S. aureus and coagulase-negative staphylococci—as the leading organisms in pin tract infections is well-documented in contemporary reviews and clinical series. Nevertheless, gram-negative bacteria such as Pseudomonas and other Enterobacterales are also frequently encountered, particularly in cases of open fractures, heavily contaminated wounds, or in tropical and developing-country settings. Recent microbiological studies continue to identify S. aureus as the principal isolate, although local epidemiology can vary, and there is a growing recognition of resistant strains, including MRSA and carbapenem-resistant organisms, in some centres.(14) In this study, most pin tract infections were of low to moderate severity, with grades 1–3 comprising the majority, and only a small fraction progressing to more severe forms such as osteitis or sequestrum formation (grades 5–6). This distribution mirrors findings in multiple contemporary series, where most PTIs remain superficial and respond to local care combined with antibiotic therapy, while only a minority advance to complications like hardware loosening or osteomyelitis. Highlighting the time-to-onset of infection and the corresponding management strategies is important: early-stage infections were generally managed with local pin-site care and oral antibiotics, whereas higher-grade infections required pin removal and surgical debridement, consistent with standard treatment algorithms reported in the literature.(14)

Pin tract infection remains a common complication following uniplanar external fixation of open tibial fractures, with an incidence of 56.5% in our cohort. Higher infection rates were significantly associated with female sex, lower educational level, lower socioeconomic status, and higher Gustilo–Anderson fracture grades. Although trends were observed for diabetes mellitus and smoking, these did not reach statistical significance. Staphylococcus aureus was the predominant pathogen, and most infections were low to moderate in severity.

These findings underscore the importance of targeted patient education, rigorous pin-site care, and early intervention, particularly for patients with severe soft-tissue injury or limited resources. Clinicians should maintain a high index of suspicion in high-risk groups and consider multidisciplinary approaches, including aggressive soft-tissue management and close postoperative monitoring, to reduce the burden of pin tract infections.

Limitations

This study has several limitations that should be acknowledged. First, the analysis was limited to univariate methods (χ² / Fisher tests). Without multivariable logistic regression, residual confounding may influence some associations—for example, educational level or socioeconomic status may be correlated with fracture severity (Gustilo grade) or time-to-debridement. A multivariable model would be required to identify independent predictors of pin tract infection (PTI).

Second, the single-centre design restricts the external generalizability of our findings, as patient demographics, injury patterns, and care protocols may differ in other settings.

Third, definitions of infection require careful consideration. It should be explicitly stated whether the PTI numerator included only clinically apparent superficial infections or also deep bone infections. Outcomes differ substantially between these categories; in this study, the Chicketts–Otterburn grading system was used, and grades ≥5 were considered to represent osteomyelitis.

Finally, microbiology results may be affected by the timing and quality of culture sampling, and prior antibiotic exposure may have led to under-reporting of certain pathogens. These limitations align with recent literature emphasizing the need for rigorously designed, prospectively collected multicentre datasets to better define risk factors and outcomes in PTI.

1. Nicolaides M, Pafitanis G, Vris A. Open tibial fractures: An overview. J Clin Orthop Trauma. 2021 Sept 1;20:101483. 2. Soni JK, Kulkarni S, Khodnapur G, Bagewadi R, Nandi SS. Management of Open Tibial Diaphyseal Fractures by Limb Reconstruction System As Primary and Definitive Treatment: A Prospective Cohort Study. Cureus [Internet]. 2023 May 31 [cited 2025 Nov 1]; Available from: https://www.cureus.com/articles/153394-management-of-open-tibial-diaphyseal-fractures-by- 3. limb-reconstruction-system-as-primary-and-definitive-treatment-a-prospective-cohort-study 4. Analysis of the Risk Factors for Free Flap Necrosis in Soft Tissue Reconstruction of the Lower Limbs - Liu - 2023 - Orthopaedic Surgery - Wiley Online Library [Internet]. [cited 2025 Nov 1]. Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/os.13727 5. The Effect of Delayed Surgical Debridement in the Management of Open Tibial Fractures: A Systematic Review and Meta-Analysis [Internet]. [cited 2025 Nov 1]. Available from: https://www.mdpi.com/2075-4418/11/6/1017 6. Schade AT, Khatri C, Nwankwo H, Carlos W, Harrison WJ, Metcalfe AJ. The economic burden of open tibia fractures: A systematic review. Injury. 2021 June 1;52(6):1251-9. 7. Frontiers | Treatment preferences and current practices regarding open tibial shaft fractures [Internet]. [cited 2025 Nov 1]. Available from: https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2024.1331654/full 8. Saini R. Bridge Plating Versus Hybrid External Fixation in the Management of Proximal Tibia Metaphyseal Fractures. Cureus [Internet]. 2023 Mar 18 [cited 2025 Nov 1]; Available from: https://www.academia.edu/143577882/Bridge_Plating_Versus_Hybrid_External_Fixation_in_the_ Management_of_Proximal_Tibia_Metaphyseal_Fractures 9. Pin tract infection after uniplanar external fixation of open fractures at a national, teaching and referral hospital | East and Central African Journal of Surgery [Internet]. [cited 2025 Nov 1]. Available from: https://www.ajol.info/index.php/ecajs/article/view/158884 10. External Fixation as a Primary and Definitive Treatment for Complex Tibial Diaphyseal Fractures: An Underutilized and Efficacious Approach - PMC [Internet]. [cited 2025 Nov 2]. 11. External Fixation as a Primary and Definitive Treatment for Complex Tibial Diaphyseal Fractures: An Underutilized and Efficacious Approach - PMC [Internet]. [cited 2025 Nov 2]. 12. Cinthuja P, Wijesinghe PCI, Silva P. Use of external fixators in developing countries: a short socioeconomic analysis. Cost Eff Resour Alloc CE. 2022 Mar 29;20:14. 13. Ukai T, Hamahashi K, Uchiyama Y, Kobayashi Y, Watanabe M. Retrospective analysis of risk factors for deep infection in lower limb Gustilo-Anderson type III fractures. J Orthop Traumatol Off J Ital Soc Orthop Traumatol. 2020 Dec;21:10. 14. Cinthuja P, Wijesinghe PCI, Silva P. Use of external fixators in developing countries: a short socioeconomic analysis. Cost Eff Resour Alloc CE. 2022 Mar 29;20:14. 15. Priyanka RMK, Anushka DV, Parimala S, Hariprasad S. Microbiological Profile of Pin Tract Infections due to External Fixators. J Clin Diagn Res [Internet]. 2021 [cited 2025 Nov 2].

Pin tract infection remains a common complication following uniplanar external fixation of open tibial fractures, with an incidence of 56.5% in our cohort. Higher infection rates were significantly associated with female sex, lower educational level, lower socioeconomic status, and higher Gustilo–Anderson fracture grades. Although trends were observed for diabetes mellitus and smoking, these did not reach statistical significance. Staphylococcus aureus was the predominant pathogen, and most infections were low to moderate in severity.

These findings underscore the importance of targeted patient education, rigorous pin-site care, and early intervention, particularly for patients with severe soft-tissue injury or limited resources. Clinicians should maintain a high index of suspicion in high-risk groups and consider multidisciplinary approaches, including aggressive soft-tissue management and close postoperative monitoring, to reduce the burden of pin tract infections.

Limitations

This study has several limitations that should be acknowledged. First, the analysis was limited to univariate methods (χ² / Fisher tests). Without multivariable logistic regression, residual confounding may influence some associations—for example, educational level or socioeconomic status may be correlated with fracture severity (Gustilo grade) or time-to-debridement. A multivariable model would be required to identify independent predictors of pin tract infection (PTI).

Second, the single-centre design restricts the external generalizability of our findings, as patient demographics, injury patterns, and care protocols may differ in other settings.

Third, definitions of infection require careful consideration. It should be explicitly stated whether the PTI numerator included only clinically apparent superficial infections or also deep bone infections. Outcomes differ substantially between these categories; in this study, the Chicketts–Otterburn grading system was used, and grades ≥5 were considered to represent osteomyelitis.

Finally, microbiology results may be affected by the timing and quality of culture sampling, and prior antibiotic exposure may have led to under-reporting of certain pathogens. These limitations align with recent literature emphasizing the need for rigorously designed, prospectively collected multicentre datasets to better define risk factors and outcomes in PTI.

1. Nicolaides M, Pafitanis G, Vris A. Open tibial fractures: An overview. J Clin Orthop Trauma. 2021 Sept 1;20:101483. 2. Soni JK, Kulkarni S, Khodnapur G, Bagewadi R, Nandi SS. Management of Open Tibial Diaphyseal Fractures by Limb Reconstruction System As Primary and Definitive Treatment: A Prospective Cohort Study. Cureus [Internet]. 2023 May 31 [cited 2025 Nov 1]; Available from: https://www.cureus.com/articles/153394-management-of-open-tibial-diaphyseal-fractures-by- 3. limb-reconstruction-system-as-primary-and-definitive-treatment-a-prospective-cohort-study 4. Analysis of the Risk Factors for Free Flap Necrosis in Soft Tissue Reconstruction of the Lower Limbs - Liu - 2023 - Orthopaedic Surgery - Wiley Online Library [Internet]. [cited 2025 Nov 1]. Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/os.13727 5. The Effect of Delayed Surgical Debridement in the Management of Open Tibial Fractures: A Systematic Review and Meta-Analysis [Internet]. [cited 2025 Nov 1]. Available from: https://www.mdpi.com/2075-4418/11/6/1017 6. Schade AT, Khatri C, Nwankwo H, Carlos W, Harrison WJ, Metcalfe AJ. The economic burden of open tibia fractures: A systematic review. Injury. 2021 June 1;52(6):1251-9. 7. Frontiers | Treatment preferences and current practices regarding open tibial shaft fractures [Internet]. [cited 2025 Nov 1]. Available from: https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2024.1331654/full 8. Saini R. Bridge Plating Versus Hybrid External Fixation in the Management of Proximal Tibia Metaphyseal Fractures. Cureus [Internet]. 2023 Mar 18 [cited 2025 Nov 1]; Available from: https://www.academia.edu/143577882/Bridge_Plating_Versus_Hybrid_External_Fixation_in_the_ Management_of_Proximal_Tibia_Metaphyseal_Fractures 9. Pin tract infection after uniplanar external fixation of open fractures at a national, teaching and referral hospital | East and Central African Journal of Surgery [Internet]. [cited 2025 Nov 1]. Available from: https://www.ajol.info/index.php/ecajs/article/view/158884 10. External Fixation as a Primary and Definitive Treatment for Complex Tibial Diaphyseal Fractures: An Underutilized and Efficacious Approach - PMC [Internet]. [cited 2025 Nov 2]. 11. External Fixation as a Primary and Definitive Treatment for Complex Tibial Diaphyseal Fractures: An Underutilized and Efficacious Approach - PMC [Internet]. [cited 2025 Nov 2]. 12. Cinthuja P, Wijesinghe PCI, Silva P. Use of external fixators in developing countries: a short socioeconomic analysis. Cost Eff Resour Alloc CE. 2022 Mar 29;20:14. 13. Ukai T, Hamahashi K, Uchiyama Y, Kobayashi Y, Watanabe M. Retrospective analysis of risk factors for deep infection in lower limb Gustilo-Anderson type III fractures. J Orthop Traumatol Off J Ital Soc Orthop Traumatol. 2020 Dec;21:10. 14. Cinthuja P, Wijesinghe PCI, Silva P. Use of external fixators in developing countries: a short socioeconomic analysis. Cost Eff Resour Alloc CE. 2022 Mar 29;20:14. 15. Priyanka RMK, Anushka DV, Parimala S, Hariprasad S. Microbiological Profile of Pin Tract Infections due to External Fixators. J Clin Diagn Res [Internet]. 2021 [cited 2025 Nov 2].