Early functional outcomes of open ankle fractures at Kenyatta National, Aga Khan University and P.C.E.A Kikuyu Hospitals

Abstract

Background: Open fractures are generally very challenging to treat due to the risk of sepsis, potential soft tissue loss and subsequent delayed or non-union. This challenge is amplified at the ankle joint because of inadequate soft tissue cover and precarious blood supply. While fractures around the ankle are the second most prevalent in Kenya, the open type are relatively uncommon but have significantly higher rates of ankle stiffness, pain, wound necrosis and infection. Open fractures are considered emergencies requiring early debridement and stabilization, the time of definitive fixation and wound closure however remains controversial. Study objective: To evaluate the early functional outcomes of open ankle fractures managed at Kenyatta National Hospital (KNH), Aga Khan University Hospital (AKUH) and Presbyterian Church of East Africa (PCEA) Kikuyu Hospital. Methods: A prospective study carried out at the A&E departments, orthopaedic wards and orthopaedic outpatient clinics of KNH, AKUH and PCEA Kikuyu Hospital over a period of twelve weeks. Ethical approval was sought from the relevant ethical boards and consent sought from each of the 62 patients recruited. Data collected included patients‘ demographics, wound characteristics according to the AO ankle fracture and soft tissue classification. The time antibiotics were commenced, time from injury to initial debridement, stabilization modality and time to definitive wound cover and fracture fixation. The patients were assessed on the fourth and the tenth day to for early infection and the ASEPSIS score was recorded. The wound was reassessed on the sixth and twelfth week determine the degree of delayed and late infection respectively. The fixation modality and whether provisional fixation was converted to definite fixation before discharge were recorded. Ankle radiographs taken at six weeks were analyzed for adequacy of fracture reduction, alignment and stability. Complications, including delayed wound infection, mal-union, stiffness and functional outcome based on AOFAS scoring system were recorded at 12 weeks. Data Analysis: The compiled data were analyzed using the IBM Corp. Statistical Package of Social Science (SPSS) for Windows version 25. Armonk, NY. The baseline characteristics were summarized and presented as means, medians and proportions. Bivariate analysis was used to evaluate factors associated with functional outcome. Pearson correlation analysis was used to assess the relationship between the intervening variables (time to initial debridement, antibiotic initiation, primary fixation and time to definitive fixation) with outcomes of interest (adequacy of reduction, infection and functional outcome). The Chi-square test was used for inferential statistics, analyzing categorical data such as the AO fracture and soft tissue category with the AOFAS score. All statistical tests were performed at 5% level of significance (95% confidence interval). The results of the study were presented in forms of tables, histograms and pie charts. Results: The age of the patients ranged from19 to 63 years with a mean age of 38 years. Of these, males formed 77%. AO type B and skin lesion IO 3 were the commonest fracture and soft tissue injury seen (64.5% and 47.7% respectively). The incidence of wound infection was 48.4% (early), 19.4% (delayed) and 14.5% (late). The radiological assessment of reduction at 6 weeks showed that 45% of the patients had anatomic reduction, 31% had fair reduction and 24% had poor reduction. At 12 weeks, 49.7% of patients had an AOFAS score above 50%, while 22.6% had poor scores (less than 39%). The radiological assessment of reduction was poorest among those stabilized with a back slab alone, leading to significantly higher rates of infection and poor AOFAS scores. The size of initial wound, debridement after 72 hours and the quality of initial fixation had a significantly increased the rate of infection and poor functional outcome. Delay in antibiotic administration beyond 72 hours also led to increased infection but not to a significant degree. Conclusion: Wound debridement within the first 72 hours, early definitive fixation and definitive fixation within the first two weeks were the main contributors to reduction of infection rates. Poor reduction and malunion were associated with higher rates of delayed infection and poor functional outcome. Additionally, the loss of reduction and poor stability was noted to be significantly higher with use of a back slab splint alone. Poor functional outcomes were attributed mainly to infection, poor reduction and failure of conversion of provisional fixation to definitive fixation.