Session 11 Flashcards

Question

What are local complications of a knee replacement?

Answer 1

* Leg length inequality (slight difference) * Dislocation (3%) * Infection (2-3%) * Loosening (usually after 10-15 years( * Neurovascular damage - Sciatic/femoral nerve, common peroneal nerve

Answer 2

The femoral artery is a continuation of external iliac artery (when the external iliac artery crosses under the inguinal ligament, it becomes the femoral artery) The femoral artery continues down the anterior surface of the thigh, via the adductor canal. During its descent the artery supplies the anterior thigh muscles. The adductor canal ends at an opening in the adductor magnus, called the adductor hiatus. The femoral artery moves through this opening and becomes the popliteal artery after entering popliteal fossa.

Answer 3

Femoral artery gives off a branch called the deep artery of the thigh which in turn gives off three main branches: perforating branches (3 or 4 arteries that perforate the adductor magnus, contributing to the supply of the muscles in the medial and posterior thigh), lateral femoral circumflex arteryand medial femoral circumflex artery.

Answer 4

Anterior and Posterior Tibial arteries

Answer 5

The obturator artery, branch of internal iliac artery and enters thigh through obturator foramen and descends via the obturator canal to enter the medial thigh, bifurcating into two branches: ~Anterior branch supplies the pectineus, obturator externus, adductor muscles and gracilis. ~Posterior branch supplies some of the deep gluteal muscles. The gluteal region is largely supplied by the superior and inferior gluteal arteries. These arteries also arise from the internal iliac artery, entering the gluteal region via the greater sciatic foramen. In addition to the gluteal muscles, the inferior gluteal artery also contributes towards the vasculature of the posterior thigh.

Answer 6

Due to rupture of retinacular arteries (mostly from medial circumflex femoral artery) The artery to the head of femur (branch of obturator artery) is more important in children à less important blood supply in adults To find the femoral pulse, place little finger on ASIS and thumb on Pubic Tubercle. The femoral pulse should be palpated 2 or 3 fingers just below inguinal ligament. The femoral artery is a common site for insertion of catheter to gain access to left side of the heart – for a coronary artery. NOTE: brachial or radial arteries could also be used. Use the femoral vein to access the right side of heart.

Answer 7

Thrombus Embolism Haemorrhage and Compartment Syndrome

Answer 8

Abdominal aorta and iliac arteries Proximal coronary arteries Thoracic aorta, femoral and popliteal arteries Internal carotid arteries Internal carotid arteries Vertebral, basilar and middle cerebral arteries

Answer 9

Comparison of lower limb pulses (femoral, popliteal, posterior tibial, dorsalis pedis) – compare pulses. Doppler ultrasound Arteriogram – X-ray following injection of radio-opaque contrast dye

Answer 10

When pressure is constant: flow is proportional to radius4 If you reduce the radius of the vessel by one half, flow will be reduced to 1/16th Partial occlusion = stenosis

Answer 11

Skin problems Lack of hair Ulcers Infection Skin necrosis Loss of pulses Cold to touch

Answer 12

Antiplatelet therapy: aspirin Risk factor modification: lipid lowering therapy, smoking cessation, BP control, diabetes control, increased exercise levels

Answer 13

Muscles and neurovascular structures in the leg are in compartments bound by strong fascia (quite inextensible) Arterial bleed increases pressure Comrpession of arteries – ischaemia May also be caused by infection or trauma which causes swelling. May have to surgically cut fascia to relieve pressure.

Answer 14

(Abnormal dilation of popliteal artery) Oedema and pain in popliteal fossa Mass with pulpable sensation – may also hear a bruit on auscultation Popliteal artery can be at risk of rupture with fracture of distal femur or dislocation of the knee

Answer 15

Arises from dorsal venous arch of foot Courses anterior to the medial malleolus Passes the media aspect of the knee – hand’s breath from patella Passes through the fascia lata at the saphenous opening to drain into the femoral vein in the femoral triangle

Answer 16

Arises from the lateral marginal vein of foot Passes posterior to the lateral malleolus Course up the posterior aspect of the calf Drains into the popliteal vein at the popliteal fossa

Answer 17

Emergency situation when it is difficult to find a vein for venepuncture or cannula insertion Great saphenous vein can be located anterior to the medial malleolus by making a skin incision at this location: risk of saphenous nerve injury which travels great saphenous vein and pain along medial border of foot. Sural nerve normally travels with short saphenous vein

Answer 18

Deep veins accompany all major arteries often as paired venae comitantes

Answer 19

Blood drains from superficial to deep via perforating veins The superficial, deep and perforating veins of the limbs all have valves which prevent backflow. Venous return is assisted by contraction of the calf muscles: contracted muscles compress the deep veins and propel blood to the heart. The blood pushed downwards will cause the lower valve to close, preventing blood flow away from the heart.

Answer 20

Dilated tortuous superficial veins Valve flaps fail to meet or become damaged and incompetent – fail to prevent backflow If there is incompetency in perforated veins, blood can flow backwards Venous insufficiency (walls are weakened, damaged valves, veins stay filled with blood especially when standing) --. Venous insufficiency ulcers typically around medial malleolus occur.

Answer 21

Risk factors: Virchow’s triad (stasis, hypercoaguability, vascular damage) Sites: (most common initial site, but can propagate), also – popliteal, femoral iliac Signs: tender swollen calf, warmth and erythema (red) of affected limb Consequences: risk of pulmonary embolism, postphlebitic syndrome

Answer 22

Chronic deep venous insufficiency --\> increased venous pressure in distal part of limb --\> increased capillary hydrostatic pressure --\> lymphoedma Damage to venous valves Lymphoedema

Answer 23

Posterior ankle tendons (mnemonic): posterior to medial malleolus, Anterior to Posterior; **Tom, Dick and Very Nervous Harry** tendon of Tibialis posterior tendon of flexor Digitorum longus tibial Artery \< \> tibial Nerve flexor Hallucis Longus