1 Introduction

Hip fractures are amongst the most commonly treated conditions by orthopaedic surgeons.¹ At our institution, basicervical femoral neck fractures are routinely treated with cephalomedullary nails (CMN)s. Pseudoaneurysm formation is a rare complication after femoral CMN. The primary cause of pseudoaneurysm formation in previous studies has been found to be related to overpenetration of the far cortex with a drill or screw.^2–4 Patients with neuromuscular diseases may have aberrant anatomy potentially leading to increased risk of pseudoaneurysm formation. To our knowledge, this is the first case report of a patient with post-polio syndrome who developed a symptomatic deep femoral artery pseudoaneurysm status post short CMN fixation for a basicervical femoral neck fracture (FNF). Here we describe the work up and management of this uncommon complication.

2 Case report

A 57-year-old female presented to the emergency department after a ground level fall, injuring her right hip. X-rays demonstrated a displaced basicervical FNF. She denied antecedent hip pain, use of ambulatory assistive devices or blood thinners, and pain elsewhere. Past medical and surgical history were significant for poliomyelitis, post poliomyelitis syndrome affecting the right lower extremity, multiple foot surgeries, and right total knee arthroplasty with residual instability and hyperextension.

The following day she was taken to the operating room for an un-reamed, short locked femoral CMN. The procedure was routine without any oblivious intra-operative complications. Post-operative films demonstrated adequate fracture reduction and placement of the antegrade femoral CMN (Fig. 1). She progressed well with physical therapy. Hemoglobin was stable between 7.9 and 9.7 post-operatively. Blood products were not required. She was placed in a hinged knee brace locked at 0° extension, open for flexion. She was discharged home.

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Fig. 1 Immediate post-op films demonstrating acceptable fracture reduction and placement of short cephalomedullary nail (CMN).

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Two months post-operatively she presented back to the hospital due to acute onset right thigh pain.

3 Clinical findings

On examination, there was tenderness throughout the posterior and proximal thigh with a palpable hematoma. Prior incisions were well healed. Neurovascularly intact including motor and sensory. Her symptoms were primarily posterior thigh swelling after walking, and a burning pain in the sciatic nerve distribution. Prior to this she was progressing well, continuing to ambulate with a walker.

4 Diagnostic assessment

Right hip CT and CT-As were obtained demonstrating a large hematoma of the posterior thigh measuring roughly 23 cm × 9 cm without evidence of active arterial hemorrhage (Fig. 2).

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Fig. 2 Two months status post femur CMN, CTA showing large posterior thigh hematoma on axial and coronal images.

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5 Therapeutic intervention

Vascular surgery and Interventional radiology (IR) consults were requested. No vascular surgical intervention was indicated. IR aspirated 20 ccs of hematoma. Cultures were sent (ultimately negative). Due to the size of the hematoma and sciatic nerve symptoms, the decision was made to proceed with formal irrigation and debridement (I&D) of the hematoma. The hematoma was evacuated and cultured. The sciatic nerve was visualized and appeared healthy without signs of chronic compression. The thigh was thoroughly irrigated, Surgiflow placed, and primarily closed. Post-op day one, the patient had decreased pain and a softer feeling thigh. Post-op day two, the patient had increased pain and fullness of the thigh, thus a repeat CT with contrast of the femur was performed which demonstrated a new intra-muscular hematoma and pseudoaneurysm of a branch of the deep femoral artery. IR was again requested to evaluate. IR successfully performed coil embolization of the pseudoaneurysm (Fig. 3). Post-embolization the patient's thigh pain and swelling gradually improved. Hematoma cultures resulted negative. Hematology was also consulted during this hospitalization and a coagulopathy work up was negative. She clinically improved and was eventually discharged home.

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Fig. 3 Intra-operative angiogram showing pseudoaneurysm and subsequent coiling.

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6 Follow-up and outcomes

12 months status post right femur CMN and 10 months status post deep femoral artery coil embolization, the patient is doing well. She has continued mild thigh pain, but is ambulatory with a walker and is neurovascularly intact. She has been non-compliant with the hinged knee brace for her total knee hyperextension. X-rays demonstrate a healed basicervical FNF and unchanged appearance of the coil (Fig. 4).

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Fig. 4 10 months status post CMN with a healed basicervical femoral neck fracture. Coil in the deep femoral artery.

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7 Discussion

Hip fractures are a common cause of injury requiring orthopedic surgery, with an estimated annual projection of up to a 1 million annual new fractures by 2050.¹ Iatrogenic vascular injury following orthopedic surgery is a rare, but serious, complication with a scarcity of published cases in the medical literature. This case report identifies a new potential risk factor, abarant anatomy secondary to neuromuscular disease (post-poliomyleitis), for vascular injury following CMN. We also summarize the relevant published literature by describing causes of injury, presentation, detection, treatment, and prevention.

Pseudoaneurysm formation after intramedullary nailing is most commonly associated with puncture injury caused by overpenetration of the drill bit or screws.^2–4 Additional potential causes of iatrogenic injury include dislodged bone fragments^5–7 or mispositioned guide wires.⁸ Patients can present with a pseudoaneurysm intraoperatively⁹ or as late as 8 months postoperatively.⁴ Due to nonspecific symptom presentation, a high level of suspicion is required with consideration given to risk factors associated with the development of femoral pseudoaneurysm, including emergent procedures, long procedure time, >60 years old, diabetes, hypertension, atherosclerosis, and female sex.^10–12 In most cases patients will complain of pain and associated swelling in the proximal thigh.^3,4,8,11 Swelling is often located in the posteromedial aspect of the of the femur but may also present along the posterolateral aspect of the femur.¹⁴ In addition to swelling, pseudoaneurysms may also present as a pulsatile mass or venous engorgement.⁷ The most commonly injured artery is the deep femoral artery.^4,5,8,14 Injury to the superficial femoral artery⁶ and the medial femoral circumflex artery¹⁶ have also been reported.

Due to the potential limb/life-threatening nature of pseudoaneurysm formation, early detection and immediate treatment is critical to patient safety. A high level of suspicion is necessary due to the potential of pseudoaneurysms to present in a similar manner to an abscess, lymphadenopathy, hematoma, or deep vein thrombosis.^5,13 Fever, unexplained intraoperative bleeding, or postoperative anemia, confirmed by serial hemoglobin, can be early indications of pseudoaneurysm formation.^5,8,13 Duplex ultrasound has demonstrated utility for early detection,^7,13,18 but most cases of pseudoaneurysm are confirmed with the use of CT angiography (CT-A).^{3,6,7,9,13,17,18} No current gold standard for the treatment of iatrogenic pseudoaneurysm secondary to orthopedic surgery has been established but treatment can generally be driven by pseudoaneurysm size. Asymptomatic vascular lesions that are smaller than 1 inch can be monitored for spontaneous obliteration.¹³ Larger pseudoaneurysms will require intervention in the form of thrombin injections, ultrasound guided compression, endovascular embolization/coiling, stenting, or surgery, depending on severity, size, and location.^7,13,15,18

To prevent pseudoaneurysm formation, care must be taken to place the lower limb in a neutral position during preparation and drilling of the distal interlocking hole. This can be accomplished by avoiding excessive adduction, internal rotation, and traction, which can alter the position of vessels and shorten the distance between nail and artery.^2,4,13 Surgeons should also be aware of the increased risk short nails pose to cause deep femoral artery damage.^18,19 Alternatively, because of this patient's stable fracture pattern, either a long unlocked or locked femoral nail could have been considered. Careful monitoring of fracture manipulation to prevent fragment displacement, guidewire placement, drill bit introduction, and selecting appropriate nail size are additional preventative measures.^2,4–8 Although rare, surgeons should remain aware of this potentially limb/life-threatening complication and of the potentially increased risk that patients with neuromuscular disease pose. Post-poliomyelitis is one such example of this. If abnormal anatomy is suspected, further pre-operative studies such as CT-A may be considered pre-operatively. Future studies may be aimed at developing a treatment algorithm for pseudoaneurysm management, as well as proper pre-operative imaging in neuromuscular patients.

Informed consent

Written informed consent for this case report was obtained from the patient, and therefore Institutional Review Board approval was unnecessary.

Ethics statement

Informed consent was obtained from the patient. There are no patient identifiers in this case report. IRB review was unnecessary. All information gathered for this case report was done so in a HIPAA compliant manner.

Financial support and sponsorship

The authors report no financial support or sponsorship pertinent to this study.

CRediT authorship contribution statement

Nicholas E. Runge: study, Conceptualization, data collection, manuscript preparation. Ryan Sanii: manuscript preparation. Johnny Kasto: manuscript preparation. Daniel P. McCall: study, Conceptualization, All authors reviewed and accepted the final manuscript.