Hemiarthroplasty is a surgical procedure in which the femoral head is removed from the acetabulum. The femoral neck is trimmed close to the trochanters and the medullary cavity of the femoral shaft is reamed. A metal hip prosthesis is inserted into the medullary cavity of the femur and the head of the prosthesis is placed into the acetabulum, in which it articulates. Importantly, the acetabulum is not replaced in straightforward cases, though a prosthetic acetabulum may be inserted if clinically appropriate.
An arthroplasty was the only procedure that could be performed.
The blood supply to the femoral head is from three sources—the artery within the ligament of the head of the femur, vessels in the medullary cavity, and vessels deep to the synovium running in the retinacula of the fibrous capsule of the hip joint. With increasing age, the medullary cavity undergoes fatty replacement of the normal red marrow, thus attenuating the medullary blood supply. The artery within the ligament of the head of the femur also becomes attenuated and this is often associated with atherosclerotic arterial disease.
Unfortunately for this patient, the sole blood supply to the head of the femur was via the vessels in the retinacula fibers, which were transected at the time of the fracture. If the patient had an intertrochanteric fracture instead, the vessels of the retinacula fibers would not have been damaged and a different approach to surgical fixation could be undertaken without the need for a hemiarthroplasty.
The patient has osteoporosis.
Osteoporosis is a common condition affecting older people, but is significantly more frequent in postmenopausal women. Many fractures of the femoral neck in elderly patients occur because the strength of the bone is significantly reduced when it is osteoporotic. Other common sites for osteoporotic fractures include the distal radius and the thoracic and lumbar vertebrae.
A 28-year-old woman was seen by her family practitioner for a routine pregnancy checkup at 36 weeks’ gestational age. Neither the patient nor the family physician had any concerns about the pregnancy. However, the patient did complain of unilateral swelling of her left leg, which had gradually increased over the previous 2 days. Furthermore, the evening before her visit she developed some sharp chest pain, which was exacerbated by deep breaths.
The family physician ordered a duplex ultrasound scan of the left leg venous system.
Ultrasound scanning of the vascular tree can demonstrate flow and occlusion of arteries and veins.
The probe was placed over the left femoral vein and no flow was demonstrated. Furthermore, the vein could not be compressed, and no alteration of flow with breathing could be demonstrated. Some flow was demonstrated in the deep femoral vein and in the great saphenous vein. No flow was demonstrated throughout the length of the left femoral vein, the popliteal vein, and the tibial veins.
The technician scanned the opposite side, where excellent flow was demonstrated within the right femoral venous system. In addition, when the calf was gently massaged an augmentation to the flow was noted. It was possible to demonstrate alteration of flow with respiratory excursion and venous compression was satisfactory. A diagnosis of extensive left-sided deep vein thrombosis was made.
Certain patients are more prone to deep vein thrombosis.
Three major factors predispose a patient to thrombosis: reduced or stagnant blood flow in the veins—significant stasis of blood (which may be due to lack of movement), reduced muscular calf pump effect, and obstruction to flow may occur; injury to the vein wall—venous trauma may damage the vessel walls, promoting thrombus formation; hypercoagulability of the blood—hypercoagulable states are often associated with abnormal levels of certain clotting factors, such as antithrombin III, protein C, and protein S.
In this patient, compression of the left external iliac veins by the gravid uterus was the likely cause of stasis, which led to the deep vein thrombosis.