Popliteal Arteriovenous Fistula Post Total Knee Replacement

Orthopaedic Surgery, Beaumont Hospital, Dublin, IrelandIntroductionThe expansion in joint replacement surgery over thelast number of years has a profound effect on quality oflife for patients with severe arthritis. As in all surgery,there are procedure specific complications. We report acase of arteriovenous fistula post total knee replace-ment. Arteriovenous fistula is an uncommon findingin a postoperative setting. Early diagnosis is importantas complications of ischaemia, claudication and highoutput cardiac failure may ensue. The majority ofpatients present with a palpable thrill over the fistula.Diagnosis is by angiography. Management may besurgical, embolisation, endovascular or conservative.Case ReportA 63-year-old patient had a background history ofrheumatoid arthritis and bilateral knee pain, whichnecessitated bilateral knee replacements 4 yearspreviously. This operation was performed underspinal anaesthetic with a tourniquet time of 1 h38 min. Access to the joint was obtained via anteriorlongitudinal and medial parapatellar subcutaneousincisions, and the patella was retracted laterally.Minimal joint space was noted with flexion restrictedto 458. Femoral and tibial components were preparedusing a Kinemax system and a medium femoral andsmall tibial prostheses inserted. The patella wasresurfaced and an extensive lateral release of thepatella performed. Her postoperative recovery wasuneventful and a range of movement of 5–608 wasachieved after intensive physiotherapy. She also had atotal right knee replacement 1 year later she had a rightdynamic hip screw inserted for a pervious intertrochanteric fracture. At routine review she describeda buzzing sensation at the back of her knee, whichoccurred 2 months post operatively.The patient was referred from the orthopaedic clinicto the vascular outpatients. The patient was asympto-matic, normotensive with a resting regular pulse rateof 84. On examination she had a palpable thrill and anaudible bruit in the left popliteal fossa. All pulses werepresent in the lower limbs bilaterally. She exhibited agrade 2/6 mid systolic murmur at the left sternalborder radiating to the carotids and audible over theclavicle. There was no diastolic element. She had noventricular gallop, and her lung fields were clear.There was no clinical evidence of decompensation.Her cardiac echo showed normal ventricular dimen-sions. Routine bloods were normal, and ECG showeda normal sinus rhythm. Ankle–brachial indices werenormal bilaterally at rest. A duplex scan (Fig. 1) of theleft popliteal fossa confirmed a high flow arteriove-nous fistula between the popliteal artery and vein butit was difficult to image the exact communication as ahigh flow was flooding the image. The vein wasdilated to a transverse diameter of 3.17 cm. A femoralangiogram was carried out (Fig. 2). There wasevidence of early venous filling of the femoral andpopliteal veins, with simultaneous filling of thefemoral and popliteal arteries. There were three mainvessels below the knee joint on the left side, and thesefindings were compatible with a large AV fistula in theregion of the popliteal fossa. The point of communi-cation was directly opposite the left knee joint.Clinically, there was no evidence of a steel syn-drome or ischaemia affecting the left lower leg, nor did