Characteristics and clinical outcome in patients after popliteal artery injury at a level I trauma center Nikolaus W. Lang, MD, Julian B. Joestl, MD, and Patrick Platzer, MD, PhD, Vienna, Austria Background: The treatment of popliteal artery injury (PAI) caused by blunt or penetrating mechanism is demanding. Concomitant injuries and prolonged ischemia are the major causes of lower extremity morbidity and poor rates of limb salvage. This study assessed the amputation rate and, subsequently, the therapeutic management and clinical outcomes regarding the affect of concomitant injuries among patients with PAI in a setting of central European trauma care. Methods: Sixty-four patients (20 female and 44 male), with an average age of 44 years (range, 17-79 years) at the time of injury, were evaluated for clinical characteristics, concomitant injuries, complications, amputation rates, and functional outcome after traumatic PAI. The mechanism of injury was blunt trauma in 35 patients (54.7%) and penetrating trauma in 29 (45.3%). The Mangled Extremity Severity Score and the Injury Severity Score were assessed initially and the modified Functional Independence Measure (FIM) Score at 12 months after the primary surgery. Results: Thirty patients (47%) returned to their normal activity level within 1 year after trauma, and 16 (25%) were limited in their daily activity or suffered from chronic pain symptoms. Within the blunt trauma group 26 of 35 patients (74%) sustained severe concomitant injuries, whereas two of 29 patients (7%) in the penetrating group showed severe concomitant injuries (P < .046). Eleven patients (17%) had to undergo revision surgery due to their associated injuries. The median modified FIM score was 10.3, whereas patients with blunt trauma had significantly lower FIM score (P < .0082). The median Mangled Extremity Severity Score was 6 points (range, 6-16 points). Primary or secondary amputation was required in 18 patients (28%) due to failure of revascularization. Patients who sustained blunt trauma had significantly higher amputation rates than those with penetrating injuries (P < .035). Conclusions: Clinical outcome and limb salvage of patients with PAI were influenced by the mechanism of trauma, concomitant injuries, prolonged ischemia time, and the type of surgical procedure. Patients after blunt trauma had a higher incidence of concomitant injuries, and (comminuted) fractures or knee dislocations and severe soft tissue damage had the highest effect on the amputation rate. (J Vasc Surg 2015;-:1-6.)

The popliteal artery is the second most commonly injured vessel in the lower limb.1 Ischemia of the lower limb caused by popliteal artery injury (PAI) is one of the major causes of lower extremity morbidity associated with poor rates of limb salvage.2,3 In instances of blunt trauma, PAIs are associated with fracture mechanisms, concomitant soft tissue injury, and posterior knee dislocation causing traction or avulsion of the vessel. This commonly leads to high rates of limb amputation and significantly worse outcome. Penetrating injuries are less common and tend to have a better outcome, with limb salvage rates of up to 84%.2-5 Although most of the published data focus on amputation rates, the difference in functional outcome among patients with PAI caused by blunt or penetrating trauma have not been described well. This study assessed the amputation rate and, subsequently, the therapeutic

From the Department of Trauma Surgery, Medical University of Vienna. Author conflict of interest: none. Reprint requests: Nikolaus W. Lang, MD, Department of Trauma Surgery, Medical University of Vienna, Waehringerguertel 18-21, 1090 Vienna, Austria (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2015 by the Society for Vascular Surgery. Published by Elsevier Inc. http://dx.doi.org/10.1016/j.jvs.2015.01.045

management and the clinical outcome regarding the affect of concomitant injuries among patients with PAI in setting of central European trauma care. METHODS The study was approved by the local ethic committee and was done in accordance with the Declaration of Helsinki. All patients gave informed consent. Study design and patient recruitment. We retrospectively analyzed prospectively collected data for all patients treated with PAI at our level I trauma center. A sample of 89 patients with PAI caused by blunt or penetrating trauma treated between January 1999 and December 2009 was sorted, and their data set was examined for completeness and accuracy. From this sample we excluded two patients who had undergone previous surgery of the ipsilateral lower limb arteries, 11 who had received primary surgical treatment before being transferred to our department, and 12 patients with an incomplete data set. The study sample comprised 64 patients (20 female, 44 male) with an average age of 44 years (range, 17-79 years) at time of injury, who were evaluated for clinical characteristics, concomitant injuries, complications amputation rates, and functional outcome after traumatic PAI. All patients attended standard follow-up visits in our outpatient clinic at 12 months after the injury. Patients were divided into two groups to compare our analysis according to the mechanism of injury: The first 1

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Table I. Causes of injury in blunt and penetrating trauma setting Cause of trauma Fall >4 meters Traffic accident Leisure accident Stab injury Laceration Piercing injury Penetration

Blunt (n ¼ 35), No.

Penetrating (n ¼ 29), No.

4 19 12 4 6 18 1

group included 35 patients (54.7%) who sustained PAI after blunt trauma, and the second group included 29 patients (45.3%) with penetrating PAIs. The causes of injury are summarized in Table I. Also assessed were associated injuries, the Injury Severity Score (ISS), Mangled Extremity Severity Score (MESS), diagnostic tools, surgical interventions, operative techniques, resource utilization, and functional outcome. Diagnosis and surgical management. The diagnosis was based on clinical and radiologic examination (presence of peripheral pulses, time of revascularization, color, and temperature) combined with preoperative imaging, including standard radiographs of the knee in two planes, the use of a handheld duplex scanner, as well as conventional or computed tomography (CT) angiography. Surgical explorations were performed according to standard arterial exposure and repair procedures. The patients were placed supine, and the injured artery was exposed through a medial approach. Proximal and distal control of the injured segment was obtained and unfractionated heparin was applied for anticoagulation at the beginning of the vascular repair. Fogarty catheter embolectomy was performed if necessary to ensure physiologic inflow and unobstructed distal flow. Arterial repair methods included primary arterial sutures, the use of autogenous vein grafts (contralateral great saphenous vein) or polytetrafluoroethylene (PTFE) vascular patches (ACUSEAL; W. L. Gore and Associates, Flagstaff, Ariz). Outcome assessment. The modified Functional Independence Measure (FIM) score was used to asses the functional outcome and degree of disability for survivors (amputees excluded) after a 12-month follow-up period in addition to the standard outpatient follow-up visit, including physical examination and, if necessary, radiographic evaluation. The FIM score was established to evaluate the level of disability along three axes: feeding, expression, and locomotion. The score for each axis ranges from 1 (full dependence on assistance) to 4 (full independence), giving a maximum total score of 12 representing full independence. Patients were considered to have a mild functional disability, if the FIM score was 9) or polytrauma (ISS >15). Of 15 patients (23.4%) who presented in shock, nine (14%) were in the blunt trauma group and six (9.4%) were in the penetrating trauma group. Within the blunt trauma group, 26 of 35 patients (74.3%) sustained severe concomitant injuries (P < .046), five (14.3%) sustained polytrauma, and four (11.4%) showed isolated injuries of one limb. One patient (2.9%) sustained concomitant injury of vein and tibial nerve. Two patients (8.6%) had combined injuries of the popliteal artery and vein. In the penetrating trauma group, 22 of 29 patients (75.9%) showed isolated PAIs, whereas two patients (6.9%) sustained a concomitant injury of the vein, tibial, or peroneal nerve. Four patients (13.8%) had combined

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Table II. Modified Functional Independence Measure (FIM) scoring system FIM score Activity Feeding

1 (dependent, total help required)

2 (dependent, partial help required)

3 (independent with device)

4 (independent)

Not drinking or eating full meals, gastronomy feeding Does not express basic needs appropriately despite prompting

Requires help, standby coaxing, Requires more than Eating I customary orthesis reasonable time to eat manner on table Expression Expresses basic needs or ideas Expresses complex ideas Expression full abstract more than half of the time, with difficulty ideas intelligibly requires prompting Locomotion Walking/wheeling 45 m without help >1 person requires standby supervision brace or crutch assistance

Fig. Characteristics and treatment algorithm. CT, Computed tomography; CT-A, computed tomography angiography.

injuries of the popliteal artery and vein. One patient had an isolated fracture of the proximal tibia with perforation of a bony fragment. Details of concomitant injuries related with vascular injury and remote from the limb after both blunt and penetrating trauma are reported in Table III. The average ISS for patients with popliteal arterial lesions and significant concomitant injuries (ISS >9) in this study was 14.4 points (range, 9-40 points), and the average MESS was 6.8 points (range, 6-16 points). None of the patients had an ISS >40 or a MESS >16. Statistical analysis revealed that penetrating injuries frequently involved concomitant venous as well as nerve injuries (P < .0021), whereas blunt trauma was more likely to be associated with fractures (P < .0044). Functional outcome. FIM score was analyzed in 46 patients (amputees were excluded for functional analysis

of the revascularized limb). Analysis of the 1-year clinical follow-up showed that 30 patients (65.3%) returned to their normal activity level #1 year after trauma, and 16 (34.7%) were recorded as having limited activity as well as occasional and chronic pain symptoms. Using the FIM score to quantify the level of disability of the survivors, we found an overall outcome score of 10.3. The average FIM score was 9.7 in the blunt trauma group, which was significantly lower (P < .0082) than in the average score of 10.9 in the penetrating trauma group. All patients were transferred to a rehabilitation center and received further physiotherapy by a skilled nurse after discharge from the rehabilitation center. Amputation rate. The overall amputation rate in our study was 28% (n ¼ 18). Amputation was required in 16 patients with blunt trauma and in two with penetrating

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Table III. Concomitant injuries in blunt and penetrating trauma setting Mechanism of injury (n ¼ 33) Concomitant injury

Blunt (n ¼ 26), No.

Penetrating (n ¼ 7), No.

14 5 4 3 1 3 6 8 4 2 4 6 2 1 9.3

1

Tibia/fibula fracture Knee dislocation Plus proximal tibia fracture Severe soft tissue damage Vein and tibial nerve injury Vein injury Thorax injury Traumatic brain injury Facial fracture Basal skull fracture Fractures of contralateral limb Forearm fractures Clavicular fractures Scapular fracture Modified FIM score

2 4 1 1

10.4

FIM, Functional Independence Measure.

injury. One amputation was performed primarily due to severe soft tissue damage, and 17 were performed secondarily, at an average of 6.5 days (range, 1-27 days) after the initial surgery, due to worsening of soft tissue and vascular failure. Amputation was required in two patients (11.8%) after direct suture of the injured popliteal artery after penetrating injury, in six (35.3%) after bypass repair, and in 10 (58.2%) after PTFE patches. One patient died postoperatively of multiple organ failure. General and treatment-related complications were noted in 16 patients (25%). Postoperative intensive care unit treatment was required for 47 patients, with an average intensive care unit stay of 11.5 days (range, 438 days). Patients who sustained blunt trauma had significantly higher amputation rates than those with penetrating injuries (P < .035). More details on amputations are reported in Table IV. Multiple regression analysis revealed that age, mechanism of injury (blunt or penetrating), presence of associated injuries and prolonged ischemia, and the surgical technique of vascular repair influenced the amputation rate significantly (Table V).

DISCUSSION PAI occurs with an incidence of 15). In contrast, only two patients (6.9%) with penetrating PAI sustained a severe trauma (ISS 9-15). Patients after blunt trauma had an average FIM score of 9.7, which was significantly lower (P < .0082) than the average score of 10.7 in the penetrating trauma group. The major limitations of the modified FIM score are the nontrauma-specific design and the effect of pre-existing disabilities in the assessment. Furthermore, 30 patients (65.3%) were able to return to their initial activity level before surgery #1 year after trauma, and only 16 patients (34.7%) were recorded to have limited activity levels due to concomitant injuries. About two-thirds of them sustained a blunt trauma. Recent literature reveals controversial opinions about the sequence of surgical repair in cases where fracture fixation and vascular repair are required.4,8-12 Some authors support the concept of urgent revascularization in case of critical perfusion or present severe ischemia of the affected leg. The primary argument of this concept is to decrease warm ischemia time.1,4,13 Otherwise, it seems to be obvious that successful revascularization of the limb in case of artery injury might be affected by a completely unstable limb. Relating to the method of external fracture fixation, stabilizing the limb before vascular repair is a simple procedure.4 In fact, there is no existing high-level evidence about the advantage of external fracture fixation compared with internal fixation, although recent studies recommended external fracture fixation.4 The temporary use of an intraluminal shunt was introduced to address this problem. The shunt restores perfusion temporarily until definite fracture fixation restoration of the injured artery is performed.14 Although Gifford et al15 reported that temporary vascular shunting did not negatively affect the outcome in their investigated series, recent data are conflicting.4 In our series, 15 of 18 patients with bony injuries consisting of compound and complicated fractures or knee dislocations underwent prior fracture fixation by the use of an external fixation system, and in three patients it was necessary to restore arterial continuity fracture fixation due to prolonged ischemia time. Three patients exceeded the critical time period of 6 hours from injury to surgical intervention, which significantly influenced the outcome concerning functional results.

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Table IV. Causes for amputation, surgical technique of vascular repair, and cause of failure Cause for amputation 18/64 (28%) Type of reconstruction, No. (%) Bypass 8 (12.5) Patch 19 (29.7) Suture 37 (57.8) Injury mechanism Blunt, 8 Penetrating (0) Blunt, 17 Penetrating (2) Blunt, 10 Penetrating, 27 Prolonged ischemia 4 Secondary vascular obliteration 2 8 2 Soft tissue damage/infection 2 Amputation 6 10 2

Table V. Multiple regression analysis: age, mechanism of injury, concomitant injuries, prolonged ischemia and the surgical technique of vascular repair influence the amputation rate significantly Variable

Regression coefficient

Age Injury mechanism Associated Injuries Time of ischemia Type of surgery

0.01 0.02 0.26 0.00 0.28

95% CI 0.02 0.28 0.00 0.02 0.01

to to to to to

0.01 0.23 0.52 0.02 0.61

P value .01 .04 .05 .01 .05

CI, Confidence interval.

However, a meta-analysis by Fowler et al16 described no significant influence on the overall amputation rate by whether the bone or vascular repair was done first. Compartment syndrome after vascular repair is associated with high rates of limb loss.5 There is still no consensus regarding a prophylactic fasciotomy to improve the outcome after PAI.3,17 Lim et al18 have suggested implementation of fasciotomy before arterial repair to induce restoration of the collateral circulation Likewise, Frykberg19 suggested that early prophylactic fasciotomy is better than therapeutic fasciotomy performed after signs of a compartment syndrome develop. In our series, fasciotomy was performed in 84.3% of the patients as a prophylactic procedure or due to clinically apparent compartment hypertension or after intracompartmental pressure measurement, which is in accordance with the literature.20 The dimensions and characteristics of the vascular defect can be used to select the indicated method of repair, including direct suture, interposition replacement, and bypass graft.4 Most cases of PAI caused by blunt trauma lead to extensive arterial disruption or avulsion. Reports of blunt arterial injuries show an incidence of graft repair of between 67% and 92%.1,2,13,21-23 Arterial repair via direct artery suture is unsuitable in most of these cases.1 These findings are consistent with the results of our series, in which 25 of 35 patients (71%) with PAI caused by blunt trauma received reconstruction by vein grafts (n ¼ 8) or synthetic vein patches (n ¼ 17). The durability of vein grafts is well documented and seems to be the best option for belowknee revascularization, whereas the use of PTFE remains controversial.4 In our series we registered the highest secondary amputation rates among patients who underwent

arterial repair by PTFE patches (55.5%), eight times due to thrombosis and two times due to infection. In contrast to the literature, we had a high rate of direct suture repair (>90%) in patients after penetrating PAI.1,7 Nevertheless, we observed the best outcome for limb salvage rates and functional outcome in this group of patients. Inadequate initial assessment and subsequent delayed vascular repair lead to amputation rates of up to 80% in patients with traumatic PAIs.22,24 The reason for delayed diagnosis of an arterial injury is thought to be due to inconspicuous clinical findings and the presence of distal pulses. Foot pulses do not rule out injury to the popliteal artery nor does normal distal capillary refill.8,22-27 Numerous diagnostic modalities are available to detect vascular injury associated with extremity trauma. Although the role of duplex ultrasound imaging in clinical practice is evolving, there is unanimous agreement in the literature about the necessity of a magnetic resonance or CT arteriography to rule out arterial injuries.4 According to the type of injury and concomitant injuries, after clinical examination, we performed a CT angiography, whereas in a patient with penetrating injury, we performed a duplex ultrasound as an emergency imaging tool. The overall amputation rate in our series was 28%. This seems to be quite high compared with the results described in other series, for example, in an analysis of the United States National Trauma Data Bank, where an amputation rate of 14.5% is described in the setting of traumatic PAI.4,5 The overall amputation rate in the blunt trauma group was 45.7%, which was significantly higher than in the penetrating trauma group (6.9%). Of all performed amputations in our series, 83.3% were due to blunt trauma. These findings seem to be consistent with those described in the current literature.5,24,28 The study has several limitations. We evaluated retrospectively a small sample size. Furthermore, we analyzed a population that was inhomogeneous in trauma mechanism, concomitant injuries, surgical procedures, and different imaging of PAI. CONCLUSIONS Blunt mechanism of trauma and concomitant injuries, such as (comminuted) fractures and knee dislocations, as well as severe soft tissue damage, lead to a significantly higher rate of amputation compared with penetrating trauma. Other factors that seem to have a negative effect

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on limb salvage rates and functional outcome are prolonged times of ischemia and the surgical procedure of arterial repair. AUTHOR CONTRIBUTIONS Conception and design: NL Analysis and interpretation: JJ Data collection: NL Writing the article: NL Critical revision of the article: PP Final approval of the article: PP Statistical analysis: JJ Obtained funding: Not applicable Overall responsibility: NL REFERENCES 1. Hafez HM, Woolgar J, Robbs JV. Lower extremity arterial injury: results of 550 cases and review of risk factors associated with limb loss. J Vasc Surg 2001;33:1212-9. 2. Hossny A. Blunt popliteal artery injury with complete lower limb ischemia: is routine use of temporary intraluminal arterial shunt justified? J Vasc Surg 2004;40:61-6. 3. Gupta R, Quinn P, Rao S, Sleunarine K. Popliteal artery trauma. A critical appraisal of an uncommon injury. Injury 2001;32:357-61. 4. Halvorson JJ, Anz A, Langfitt M, Deonanan JK, Scott A, Teasdall RD, et al. Vascular injury associated with extremity trauma: initial diagnosis and management. J Am Acad Orthop Surg 2011;19:495-504. 5. Mullenix PS, Steele SR, Andersen CA, Starnes BW, Salim A, Martin MJ. Limb salvage and outcomes among patients with traumatic popliteal vascular injury: an analysis of the National Trauma Data Bank. J Vasc Surg 2006;44:94-100. 6. Dua A, Desai SS, Shah JO, Lasky RE, Charlton-Ouw KM, Azizzadeh A, et al. Outcome predictors of limb salvage in traumatic popliteal artery injury. Ann Vasc Surg 2014;28:108-14. 7. Dua A, Patel B, Desai SS, Holcomb JB, Wade CE, Coogan S, et al. Comparison of military and civilian popliteal artery trauma outcomes. J Vasc Surg 2014;59:1628-32. 8. Wright LB, Matchett WJ, Cruz CP, James CA, Culp WC, Eidt JF, et al. Popliteal artery disease: diagnosis and treatment. Radiographics 2004;24:467-79. 9. Karavias D, Korovessis P, Filos KS, Siamplis D, Petrocheilos J, Androulakis J. Major vascular lesions associated with orthopaedic injuries. J Orthop Trauma 1992;6:180-5. 10. Huynh TT, Pham M, Griffin LW, Villa MA, Przybyla JA, Torres RH, et al. Management of distal femoral and popliteal arterial injuries: an update. Am J Surg 2006;192:773-8.

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