To the authors' knowledge, this is the first case report describing iatrogenic vascular injury in the knee after a genicular RFA procedure. Genicular nerve RFA primarily relies on bony landmarks, and usual technique may fail to provide adequate visualization of vascular structures. Vascular injury is a rare complication even following knee surgeries, particularly injury to the genicular arteries. A study by Vincent and Stanish25 reported only 2 cases of genicular artery injury (inferior lateral genicular and descending genicular artery) out of 2,800 knee procedures. The first report of damage to a genicular artery was made in 1987 by Manning and Marshall16, who reported injury to the lateral inferior genicular artery after a diagnostic arthroscopic procedure in a patient with anterior cruciate ligament rupture. Despite case reports of genicular vascular injury in the surgical literature, the etiology of injury remains unclear, but studies suggest perforation by a retractor, damage to atherosclerotic arteries, tourniquet-mediated injury, direct vessel injury, and secondary injury from cement heat (ie, during knee arthroplasty).15
The complexity of knee joint innervation is demonstrated by the genicular nerves arising from branches of the sciatic, femoral, and obturator nerves, all of which are derived from the lumbar plexus.9 Cadaveric studies reveal the lateral superior genicular nerve arises from the common peroneal division of the sciatic nerve about 8 to 10 cm above the knee joint line and travels deep to the biceps femoris and iliotibial band. The tibial nerve gives rise to the medial superior and medial inferior genicular nerves located at the medial aspect of the knee joint.9,13 The saphenous nerve gives off the suprapatellar and infrapatellar genicular nerves, which innervate the anterior portion of the knee.10 These aforementioned genicular nerves travel in close proximity to the lateral superior, medial superior, and medial interior genicular arteries.7 Despite comprehensively describing the anatomical locations of vasculature and innervation within the knee, cadaveric studies also highlight the high degree of variation in anatomy leading to disparities in procedural technique.2,6,17 Given that genicular RFA is a typically treatment for post–total knee arthroplasty pain, the pain proceduralist must be cognizant that the path taken by the genicular nerves can vary considerably among individuals and might be unpredictable due to axonal misrouting and aberrant reinnervation.22
Vascular injury may go unnoticed for many days and even weeks. This may be due to the compressive bandaging applied at the end of a surgery or procedure.14,16 In addition, the improper use of Doppler with adequate signal in distal vessels may provide false reassurance.24 Finally, the low incidence of vascular injury predisposes the proceduralist to have a low suspicion of this complication on their differential diagnosis.
In terms of diagnostic modalities and treatment, the literature highly favors angiography and embolization, although these recommendations are anecdotal.19,21 Advantages with this approach include minimal exposure through percutaneous arterial catheterization of the femoral artery with decreased infection risk, combination of diagnosis and therapeutic intervention in one single procedure, no necessity for general anesthesia, and no alterations or restrictions postprocedurally in rehabilitation programs. For larger hematomas due to damage of larger vessels such as the popliteal artery, reconstruction with or without a vein graft or angioplasty patching is recommended.14
In our case report, although we did not pursue angiography to specifically localize the affected artery, the location of the hematoma on MRI suggests bleeding may have occurred at the medial superior genicular artery. The probable mechanism of injury may be direct shear injury to the vessel wall from radiofrequency probe insertion. We initially pursued conservative measures with rest, ice, compression, and elevation, although with close follow-up and low threshold to admit patient for further vascular intervention (eg, angiography with embolization) if his knee swelling worsened.
In conclusion, although large randomized trials are lacking on genicular RFA, this relatively novel procedure has been increasingly used among pain interventionists to treat chronic knee pain. Data on long-term efficacy and adverse outcomes are largely unavailable. Our case report emphasizes the proximity of genicular arteries to the nerves targeted by RFA and the possibility of vascular injury related to this procedure. Pain medicine physicians and orthopedic surgeons should be aware of the vascular anatomy of the knee, particularly paying close attention to variations after previous surgeries. While supportive conservative measures including rest, ice application, and elevation may treat the patient symptomatically, angiography with selective embolization is also a minimally invasive option with good outcomes. Future studies should investigate whether concomitant use of ultrasonography with fluoroscopy to visualize and avoid vasculature during genicular RFA may be associated with lower rates of vascular injury. Alternatively, pulsed or cooled RFA provides excellent alternatives that minimize the chance of tissue damage compared with conventional RFA, and studies should investigate vascular injury outcomes with these alternative approaches. In pulsed RFA, tissue damage does not occur because the temperature limit is 42°C13; although pulsed RFA of the sciatic nerve5 and saphenous nerve1 has been described in the treatment of chronic knee pain, future studies evaluating pulsed RFA of genicular nerves are warranted.
The authors have no conflict of interest to declare.
. Akbas M, Luleci N, Dere K, Luleci E, Ozdemir U, Toman H. Efficacy of pulsed radiofrequency treatment on the saphenous nerve in patients with chronic knee pain
. J Back Musculoskelet Rehabil 2011;24:77–82.
. Choi WJ, Hwang SJ, Song JG, Leem JG, Kang YU, Park PH, Shin JW. Radiofrequency treatment relieves chronic knee osteoarthritis pain: a double-blind randomized controlled trial. PAIN 2011;152:481–7.
. Complications in arthroscopy: the knee and other joints. Committee on complications of the arthroscopy association of North America. Arthroscopy 1986;2:253–8.
. Cunningham RB, Mariani EM. Spontaneous hemarthrosis 6 years after total knee arthroplasty. J Arthroplasty 2001;16:133–5.
. E Djibilian Fucci R, Pascual-Ramírez J, Martínez-Marcos A, Mantecón JM. Ultrasound-guided sciatic nerve pulsed radiofrequency for chronic knee pain
treatment: a novel approach. J Anesth 2013;27:935–8.
. El-Hakeim EH, Elawamy A, Kamel EZ, Goma SH, Gamal RM, Ghandour AM, Osman AM, Morsy KM. Fluoroscopic guided radiofrequency of genicular nerves for pain alleviation in chronic knee osteoarthritis: a single-blind randomized controlled trial. Pain Physician 2018;21:169–77.
. Franco CD, Buvanendran A, Petersohn JD, Menzies RD, Menzies LP. Innervation of the anterior capsule of the human knee: implications for radiofrequency ablation
. Reg Anesth Pain Med 2015;40:363–8.
. Haddad FS, Prendergast CM, Dorrell JH, Platts AD. Arteriovenous fistula after fibular osteotomy leading to recurrent haemarthroses in a total knee replacement. J Bone Joint Surg Br 1996;78:458–60.
. Hirasawa Y, Okajima S, Ohta M, Tokioka T. Nerve distribution to the human knee joint: anatomical and immunohistochemical study. Int Orthop 2000;24:1–4.
. Jamison DE, Cohen SP. Radiofrequency techniques to treat chronic knee pain
: a comprehensive review of anatomy, effectiveness, treatment parameters, and patient selection. J Pain Res 2018;11:1879–88.
. Julien TP, Gravereaux E, Martin S. Superior medial geniculate artery pseudoaneurysm after primary total knee arthroplasty. J Arthroplasty 2012;27:323.e13–6.
. Katsimihas M, Robinson D, Thornton M, Langkamer VG. Therapeutic embolization of the genicular arteries for recurrent hemarthrosis after total knee arthroplasty. J Arthroplasty 2001;16:935–7.
. Kim SY, Le PU, Kosharskyy B, Kaye AD, Shaparin N, Downie SA. Is genicular nerve radiofrequency ablation
safe? A literature review and anatomical study. Pain Physician 2016;19:E697–705.
. Lamo-Espinosa JM, Llombart Blanco R, Valentí JR. Inferior lateral genicular artery injury during anterior cruciate ligament reconstruction surgery. Case Rep Surg 2012;2012:457198.
. Langkamer VG. Local vascular complications after knee replacement: a review with illustrative case reports. Knee 2001;8:259–64.
. Manning MP, Marshall JH. Aneurysm after arthroscopy. J Bone Joint Surg Br 1987;69:151.
. McCormick ZL, Reddy R, Korn M, Dayanim D, Syed RH, Bhave M, Zhukalin M, Choxi S, Ebrahimi A, Kendall MC, McCarthy RJ, Khan D, Nagpal G, Bouffard K, Walega DR. A prospective randomized trial of prognostic genicular nerve
blocks to determine the predictive value for the outcome of cooled radiofrequency ablation
for chronic knee pain
due to osteoarthritis. Pain Med 2018;19:1628–38.
. Neagoe RM, Bancu S, Muresan M, Sala D. Major vascular injuries complicating knee arthroscopy. Wideochir Inne Tech Maloinwazyjne 2015;10:266–74.
. Noorpuri BS, Maxwell-Armstrong CA, Lamerton AJ. Pseudo-aneurysm of a geniculate collateral artery complicating total knee replacement. Eur J Vasc Endovasc Surg 1999;18:534–5.
. Oishi CS, Elliott ML, Colwell CW. Recurrent hemarthrosis following a total knee arthroplasty. J Arthroplasty 1995;10(suppl l):S56–8.
. Pritsch T, Parnes N, Menachem A. A bleeding
pseudoaneurysm of the lateral genicular artery after total knee arthroplasty—a case report. Acta Orthop 2005;76:138–40.
. Protzman NM, Gyi J, Malhotra AD, Kooch JE. Examining the feasibility of radiofrequency treatment for chronic knee pain
after total knee arthroplasty. PM R 2014;6:373–6.
. Sherman OH, Fox JM, Snyder SJ, Del Pizzo W, Friedman MJ, Ferkel RD, Lawley MJ. Arthroscopy—“no-problem surgery.” An analysis of complications in two thousand six hundred and forty cases. J Bone Jt Surg Am 1986;68:256–65.
. Tawes RL, Etheredge SN, Webb RL, Enloe LJ, Stallone RJ. Popliteal artery injury complicating arthroscopic menisectomy. Am J Surg 1988;156:136–8.
. Vincent GM, Stanish WD. False aneurysm after arthroscopic meniscectomy. A report of two cases. J Bone Joint Surg Am 1990;72:770–2.
. Zorbas G, Samaras T. A study of the sink effect by blood vessels in radiofrequency ablation
. Comput Biol Med 2015;57:182–6.