1 Introduction

There is an elevated risk of popliteal artery injury associated with trauma around the knee. The proposed reason is the anatomical path of the artery whereby it is anchored in the popliteal fossa by being attached to both the proximal tunnel, which is found in the adductor hiatus, and the distal tunnel which is found at the insertion of the soleus muscle.¹ This anchoring has the effect of reducing the mobility of the artery, which in turn increases the likelihood of vascular injury in patients who have knee dislocation, distal femur fractures, and proximal tibia fractures. The artery is near osseous structures as well.¹

A single damage to the vascular system can result in devastating consequences, including the amputation of limbs. The total amount of time during which ischemia occurs is directly proportional to the likelihood of amputation. When the repair is done after 8 h, there is an 85 % chance that the leg may have to be amputated.^2–4The identification of vascular damages established through a comprehensive clinical assessment and subsequently confirmed through radiological investigation. A straightforward clinical examination of the distal pulses is not sufficient for doing a clinical assessment of the popliteal artery injury. The study conducted by Barnes et al. revealed that distal pulses have a sensitivity of 79 %, specificity of 91 %, negative predictive value of 93 %, and positive predictive value of 75 %.³

The present plethora of scientific literature provides support for the clinical assessment of popliteal artery injury by emphasising the soft and hard signs of vascular injury.^4,5 Patients who have soft signs of vascular injury have a prevalence between 3 and 25 %.^6–8 To do a Computed Tomography Angiogram (CTA) on all of the patients who have mild signs of vascular damage would not be an efficient use of the available resources. The utilisation of the Ankle-Brachial Index (ABI) serves as a valuable and economically efficient tool in the evaluation of patients displaying subtle indications of vascular impairment. Recent studies have demonstrated that the Ankle-Brachial Index (ABI) exhibits a sensitivity, specificity, and positive predictive value (PPV) of 100 %.⁹

Research has indicated that there is a fluctuating occurrence of vascular injuries in the vicinity of the knee joint. Vascular injuries are found in approximately 1–2 % of cases involving fractures of the distal femur, but knee dislocations are responsible for a higher proportion, ranging from 22 to 33 %.^10,11 Vascular injuries are related to proximal tibia fractures at a rate ranging from 1.5 to 2.8 %.¹² Incidence of vascular injuries varies greatly from one author to the next, and there is a significant difference between civilian and military populations, urban and rural geographic locations, and between blunt and penetrating mechanisms of injury.The primary goal of this research is to ascertain the prevalence of vascular injuries in relation to the current clinical practices implemented at our hospital.

2 Methods

This study employed a retrospective quantitative approach to investigate the occurrence of vascular injury in individuals who sustained orthopaedic knee trauma at our hospital. The study population consisted of individuals who sustained knee injuries between June 01, 2017 and June 30, 2022. The objectives were to determine the prevalence of vascular injury on the knee, to assess the efficacy of clinical assessment, and to evaluate the cost of CTA at our hospital.

The study included all adult patients diagnosed with a distal femoral fracture, knee instability, or proximal tibia fracture who were referred for CTA to determine their vascular injury. Individuals with missed vascular injuries and those lacking clear data on the PACS were excluded. Age, sex, mechanism of injury, orthopaedic knee injury, indication for CTA, and CTA results from the hospital medical records database were obtained.

3 Statistical analysis

The data were collected, entered in Microsoft Excel (Microsoft, Redmond, WA, USA), and analysed using the STATA software, version 17 (Stata Corp, College Station, TX, USA). Descriptive statistics were used to summarise the results. Categorical variables were presented as frequencies and percentages. Prevalence was assessed through the use of descriptive statistics, specifically in terms of percentage. The confidence interval was computed utilising the prescribed statistical formula. The level of statistical significance was set at a p-value of 0.05.

4 Results

The total number of 515 cases were retrieved through the Picture Archiving and Communication System (PACS). A total of 389 patients had CTA, whereas 126 patients received radiological investigations for orthopaedic surgery planning, with no CTA operations performed.

The overall prevalence of vascular injuries among individuals who had musculoskeletal knee trauma at our hospital was found to be 9.7 %. These vascular injuries included cut-off, intimal flap, arteriovenous fistulas, aneurism, and pseudo-aneurism. The vascular injuries involved the popliteal artery and the area of trifurcation. The confidence interval was determined to be 7.1–12.3 %. Out of the 515 cases gathered, it was observed that 359 patients (69.7 %) were identified as males, while 156 patients (30.3 %) were identified as females. The prevalence of vascular injuries in males and females exhibited a comparable distribution, with rates of 9.7 % and 9.6 %, respectively (Fig. 1, Table I).

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Fig. 1 Distribution of vascular injuries according to gender.

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The number of cases of orthopaedic knee trauma was frequently observed in individuals between the ages of 21 and 40 years. However, the prevalence was found to be higher in individual under the age of 20, with a rate of 37.5 %, followed by those between the ages of 21 and 40 years, with a rate of 17.7 %. The prevalence of vascular injury was found to be lower in those below the age of 40 years, specifically at a rate of 5.8 % as depicted in Fig. 2.

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Fig. 2 Distribution of vascular injury according to age.

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The orthopaedic knee trauma was attributed to several mechanisms of injury, including falling from a standing height (130 cases), gunshot wounds (129 cases), falling from a height (56 cases), and other forms of blunt trauma (25 cases) (Fig. 3). The other blunt injuries encompassed sports-related incidents, instances of objects falling onto the knee, and instances of the knee colliding with objects. The likelihood of vascular injuries was found to be significantly elevated in patients who had gunshot wounds, with a prevalence rate of 17.8 %. The prevalence in individuals with gunshots was followed by falling from a standing height, accounting for 8.5 %. Other blunt injuries accounted for 8 % of the cases, followed by road accidents at 6.3 % and falling from a height (FFH) at 5.4 %.

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Fig. 3 Distribution of vascular injuries according to mechanism of injury.

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The prevalent orthopaedic knee injuries observed in the study were proximal tibia fractures (n = 275), distal femur fractures (n = 128), knee dislocation (n = 91), and floating knee (n = 21), in that order. The prevalence of vascular injuries was found to be greater in cases of knee dislocations (15.4 %), followed by distal femur fractures (11.7 %), floating knee (9.5 %), and proximal tibia fractures (6.9 %). The prevalence of vascular injury was found to be higher (31.6 %) in individuals exhibiting hard signs compared to those presenting with soft signs (10.8 %).

The fee charged by the hospital for CTA was R10 215.00. This was the charge to patients who do not receive any form of assistance from the government. The total cost of the CTA for all 389 patients referred for this procedure was determined to be R3 973 635.00. An amount of R388 170.00 was expended on those patients exhibiting hard signs. The cost incurred on patients with soft signs was R3 585 465.00. The cost incurred in patients with soft signs and also did not have vascular injury was R3 197 295.00.

5 Discussion

There was a large range reported for the prevalence of vascular injury in patients with orthopaedic knee trauma. This range was 5–45 %.^10–14 The large range observed in the literature is influenced by various aspects, including population demographics, geographical distribution, and the type of injury. These factors encompass distinctions such as military versus civilian populations, urban versus rural settings, and the differentiation between penetrating and blunt injuries. This study was conducted at our hospital, an urban location with a civilian population, and the prevalence of vascular injury among patients with orthopaedic knee trauma was found to be 9.7 %. The observed prevalence in our study fell within the wide range reported in the literature, however, it is greater than the 0.4 % prevalence demonstrated by Bernhoff et al. in a study that shared significant similarities with our research.⁹

Despite the disproportionate gender distribution in our study, with males comprising 69.7 % and females comprising 30.3 % of the study, the prevalence of the observed phenomenon remained consistent at approximately 9.7 % for both groups. There is no discernible association between gender and elevated susceptibility to vascular injury after orthopaedic trauma involving the knee in individuals. The number of gunshot injuries was notably greater among males than females. The occurrence of gunshots is positively correlated with a higher likelihood of vascular injury. Female patients exhibited a considerably higher rate of knee dislocation. The risk of vascular injury was raised in patients with dislocated knees. This ensured that there was no discernible difference in prevalence between the genders. This finding contradicts the study by Bernhoff et al. who discovered that being male was identified as a separate risk factor for vascular injury in persons with knee injuries.⁹

The demographic group comprising the largest proportion of individuals diagnosed with orthopaedic knee damage consisted of people aged from 21 to 40 years. However, a correlation has been identified between the age of individuals and the occurrence of vascular injury, with a higher prevalence noted among those in younger age groups. The age-related distribution of vascular injury found in this study is consistent with the findings reported in other investigations of a similar nature.^9,15 Both this study and other published studies indicate that the prevalence of the condition is more pronounced among those aged below 40 years.^9,15

Road accidents were found to be the primary cause of a significant proportion of orthopaedic knee injuries. Conversely, there was a notable increase in the occurrence among individuals who had experienced gunshot injuries. This aligns with the prevailing findings documented in the existing literature. Among patients who fell from a standing height, the occurrence of vascular injury was seen to be the second highest. The primary cause for nearly every case of knee dislocations can be attributed to the mechanism of injury (MOI) involving falls from standing height. Based on the findings reported in the literature, knee dislocation has been recognised as an independent risk factor for vascular injury.¹⁰ The occurrence of vascular injury among individuals who experience falls from a standing height is heightened by knee dislocations.

Patients with knee dislocation exhibited a notably higher prevalence of vascular injury. This phenomenon bears resemblance to the existing literature, wherein it has been empirically established that knee dislocations possess the characteristic of being an independent risk factor for vascular injury. The findings of this study revealed a prevalence rate of 15.4 %. The observed prevalence falls within the range of 5–45 % as reported in the literature.^10–14 This prevalence still does not warrant CTA investigation in all individuals with knee dislocation. The prevalence in patients with distal femur fractures was 11.5 %. This finding exceeds the reported prevalence in the existing literature. Plenty of vascular injuries observed in individuals with distal femur fractures were attributed to gunshots. In closed femur fractures, the prevalence is reported to be 1–2 %.¹⁶ In this study, the prevalence in closed fractures was double that reported in the literature. In this study, it was shown that proximal tibia fractures had the lowest prevalence of vascular injuries, accounting for just 6.9 % of cases. This was higher than the 1.5–2.8 % reported in the literature.¹⁶

The prevalence was 4 % in penetrating MOI. The prevalence in patients with proximal tibia fracture due to blunt trauma was 2.9 %. Protocols that have been published based on evidence argue for on-table angiograms and exploration thereof. The utilisation of CTA in individuals exhibiting hard signs of vascular injury has been observed to result in a prolongation of the reperfusion by repair. In terms of accurate clinical acumen, patients who had hard signs should not have been referred for CTA. The occurrence of vascular injury was seen to be low among patients displaying soft signs. In the 389 patients done CTA only 50 (12.9 %) had abnormal CTA. This was low compared to study by Jordaan et al. where they found 44 %.¹⁷ The present clinical screening procedures have not effectively alleviated the workload on CTA to a satisfactory extent.

The hospital charges a fee amounting to R10 215.00 for CTA only on patients who do not get any type of subsidy. This amount is more representative of total cost of each CTA. Therefore, the total cost for all patients who were sent for CTA was calculated to be R3 973 635.00 based on this amount. The financial expenditure incurred by CTA in individuals with hard signs of vascular injury amounted to R388 170.00. R3 585 465.00 was spent on patients with soft signs. R3 197 295.00 was spent on patients who had soft signs and no vascular injuries on CTA. The cost and the burden in CTA could have been reduced if ABI was used to screen patients with soft signs. The most cost of the CTA (81 %) was on patients with soft signs of vascular injury.

6 Conclusion

The current practice of investigating individuals with orthopaedic knee trauma for vascular injury is costly and a burden to CTA. Of every 100 patients with orthopaedic trauma on the knee, 9.7 had vascular injury. Soft signs of vascular injury should not be an indication of CTA. Further screening is necessary for these patients. It is prudent for our hospital to have a protocol on how to investigate vascular injuries and redo the same study.

CRediT authorship contribution statement

Nangamso Mkombe: study conceptualisation, data capture, data analysis, manuscript preparation, revision and approval of final manuscript. Sebastian Keith Mcdonald Magobotha: Manuscript revision and approval of final manuscript. Maxwell Jingo: study conceptualisation, manuscript revision and approval of final manuscript. Collen Sandile Nkosi: manuscript design, manuscript preparation, revision and approval of final manuscript. Richard Danny Kgabu: study conceptualisation, manuscript revision and approval of final manuscrip.

Guardian/patient consent

No guardian/patient consent was needed for this study as this study was a retrospective review.

Prior to the commencement of the study, ethical approval was obtained from the Human Research Ethics Committee (Medical) of the University with reference number: M230201.

Disclosure

No grant, equipment, or other items to disclose.

Financial remuneration

None.

Ethics statement

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Prior to the commencement of the study, ethical approval was obtained from the Human Research Ethics Committee (Medical) of the University with reference number: M230201.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.