Pedretti Ch. 40 -- Total Joint Replacement and Hip Fracture pt. 1

Question 1

Risk factors for hip fractures

Answer 1

• The elderly population is most at risk for hip fractures
• Reduced mobility and the presence of osteoporosis are two specific risk factors
• Elderly women in particular develop osteoporosis to a greater degree than men and thus tend to have more hip fractures when they fall

Question 2

Mobility is compromised in the elderly because of:

Answer 2

• Mobility is compromised in the elderly because of decreased flexibility, diminished strength, reduced vision, slowed reaction time, and the use of assistive ambulatory aids such as canes/walkers
• Improper use of cane/walker or not seeing a step are common causes for falling

Question 3

Primary candidates for LE joint replacement

Answer 3

People with history of osteoarthritis or other rheumatic disease are primary candidates for LE joint replacement

Question 4

General Medical Management of Fractures

Answer 4

• A fracture occurs when the bone’s ability to absorb tension, compression, or shearing forces is exceeded. The healing process begins after the fracture. Osteoblasts (cells that form the bone) multiply to mend the fracture. A good blood supply is necessary to supply the cells with oxygen for proper healing
• It may take several months for a fracture to heal completely – the time varies with age and heath of client, the size and configuration of the fracture, the initial displacement of the bone, and the blood supply to the fragments

Question 5

Etiology of fractures

Answer 5

• Trauma is the major cause and in most cases, occurs as a result of falling
• Poor lighting, throw rugs, and unmarked steps are particular hazards
• Osteoporosis is a common bone disease that affects people as they age and results in decreased bone density, most commonly in the vertebral bodies, the neck of the femur, the humerus, and the distal end of the radius
• Because the bones become fragile, they are prone to fracture
• A pathological fracture can occur in a bone weakened by disease or tumor, as with osteomyelitis and cancers that have metastasized to the bone

Question 6

Goals of fracture management

Answer 6

The goals of fracture management are to relieve pain, maintain good positioning, allow fracture healing, and restore optimal function to the client

Question 7

Medical and Surgical Management - Procedure

Answer 7

• Closed procedure (manipulation) or by an open procedure (surgery)

Question 8

WB restrictions

Answer 8

NWB (non weight bearing), TTWB (toe-touch weight bearing), PWB (partial weight bearing), WBAT (weight bearing at tolerance), and FWB (full weight bearing)

Question 9

Femoral Neck Fractures

Answer 9

• Femoral neck fractures (which includes subcapital, transcervial, and basilar fractures), are common in adults over 60 years old and occur more frequently in women
• Can occur from even a slight trauma or rotational force if the bone is osteoporotic
• Treatment in this area is complicated by poor blood supply, osteoporotic bone that is not suited to hold metallic fixation, and a thin periosteum covering the bone
• The type of surgical treatment is dependent on the amount of displacement and the circulation in the femur head
• The age and health of client are considered in deciding on the surgical procedure
• Generally, hip pinning (application of a compression screw and plate) is used when displacement in minimal to moderate and bloody supply is intact
• Client usually able to begin limited out-of-bed activities 1-3 days after surgery
• WB restrictions and assistive device often used for 6-8 weeks

Question 10

Femoral Neck Fractures – With severe displacement or in case of femoral head with poor blood supply (avascular) or nonunion (poorly healing fracture site where new bone does not form) and degenerative joint disease

Answer 10

With severe displacement or in case of femoral head with poor blood supply (avascular) or nonunion (poorly healing fracture site where new bone does not form) and degenerative joint disease, the femoral head is surgically removed and replaced by an endoprosthesis

• This joint is sometimes referred to as a hemipolar arthroplasty or hemiarthroplasty
• WB restrictions sometimes indicated
• Depending on approach (posterior or anterior), position precautions must be observed
• Clients usually out-of-bed activities within 1-3 days post op

Question 11

Intertrochanteric Fractures

Answer 11

• Fractures that occur between the greater and lesser trochanter are extracapsular, and the bloody supply is not affected
• Usually caused by direct trauma or force over the trochanter (such as fall)
• Occur mostly in women but in a slightly older age group
• Preferred treatment is ORIF and a nail or compression screw with a sideplate is used
• WB restrictions usually for 4 months
• Client is usually out of bed 1-3 days after surgery

Question 12

Subchanteric Fractures

Answer 12

• Subchanteric fractures 1-2 inches below the lesser trochanter usually occur because of direct trauma (such as falls, MVA, or direct blow)
• Most often seen in persons younger than 60 years old
• Skeletal traction followed by an ORIF is the usual treatment. A nail with a long sideplate or an intermedullary rod is used
  (An intramedullary rod is a rod inserted through the central part of the shaft of bone to help maintain proper alignment for healing)

Question 13

Hip Joint Replacement – Etiology and Medical Management

Answer 13

• Restoration of joint motion and management of pain by total hip replacement is sometimes indicated, primarily in osteoarthritis, rheumatoid arthritis, and occasionally in other disease processes
• Degenerative joint disease may develop spontaneously in middle age. Degenerative changes may also develop as result of trauma, congenital deformity, or a disease that damages articular cartilage
• WB joints such as hip, knee, and lumbar spine are usually affected
• In the hip, there is a loss of cartilage centrally on the joint surface and formation of osteophytes on the periphery of acetabulum, producing joint incongruity
• Pain originates from the bone, synovial membrane, or fibrous capsule and from muscle spasm
• When movement of the hip causes pain, muscles shorten, which can result in hip flexion, adduction, and internal rotation
• Rheumatoid arthritis may involve the hip joint and surgery is often performed early in disease to limit fibrotic damage
• Other disease processes (e.g. lupus and cancer) and some medications can compromise the blood flow to the hip joint and lead to avascular necrosis or osteoporosis
• When conservative forms of management (such as cortisone shots) fail, a total joint replacement is often successful in restoring function (but will not be done if patient will not comply with a rehab program)

Question 14

Two mechanical components to a total hip replacement

Answer 14

A high-density polyethylene socket is fitted into acetabulum, and a metallic prosthesis replaces the femoral head and neck. Methylmethacrylate or acrylic cement fixes the components to the bone

Question 15

Hip replacement when cement fixation is used

Answer 15

Most surgeons do not restrict WB when cement fixation is used. However, one major problem with total hip replacement is the loss of fixation at the prosthesis interface with the remaining bone. The use of biologic fixation can improve fixation. Precautions are the same with this, except there is no WB for 6-8 weeks

Question 16

Joint resurfacing

Answer 16

Joint resurfacing (when femur is capped by a metallic shell, and acetabular cavity receives a plastic cup) is less common but no WB restrictions apply

Question 17

Hip Precautions -

Posterolateral approach

Answer 17

no hip flexion greater than 90, no internal rotation, no adducation

Question 18

Hip Precautions - Anterolateral Approach

Answer 18

no external rotation, no adduction, no extension

Question 19

Knee Joint Replacement – Etiology and Medical Management

Answer 19

• Degenerative changes in the knee joint often due to osteoarthritis, trauma, or other rheumatic conditions
• Knee replacement is designed to alleviate pain, increase motion, and maintain alignment and stability of knee when conservative treatment has failed
• Process involves cutting away damaged parts of bone and attaching prosthesis for new joint

Question 20

When is TKA indicated?

Answer 20

Total knee replacement or arthroplasty (TKA) is indicated when 2+ compartments of the knee are damaged

Question 21

When is UKA indicated?

Answer 21

A partial or unicompartmental knee arthroplasty (UKA) is indicated if there is medial or lateral compartmental damage between femur and tibia

The UKA is often minimally invasive which allows greater knee flexion more quickly after surgery, and because fewer ligaments are cut, increased stability is obtained immediately

Question 22

Prosthetic devices for KA

Answer 22

Various prosthetic devices are chosen based on condition of client – a fixed platform only allows flexion and extension of knee, but a rotating one allows the normal slight rotation of a knee. The rotating is typically used for younger, active clients or for women (women have more rotation in knee than men)

Question 23

Prosthesis cementation

Answer 23

Prosthesis can be cemented or not. With cemented, WBAT is allowed, but with non-cemented, WB is usually avoided

Question 24

KA precautions

Answer 24

• Clients may start out-of-bed after 1-3 days
• Clients sometimes use knee immobilizer and should avoid rotation of knee for up to 12 weeks post-op
• Maintaining mobility (via flexion) is important for healing

Question 25

Special Consideration for Lower Extremity Joint Replacements

Answer 25

• Individuals with joint changes that result in increasing pain may have multiple joint involvement (i.e. both hips or both knees)
• Some clients opt to have both joints done at same time or within 3-7 days, but this can complicate rehab process
• Important to be aware of complicated or special procedures from surgery. Complications include dislocation, degeneration of parts, fracture of bone next to implanted parts, loosening of parts, and infection of joint
• Emphasis in rehab is on maintain/increasing joint motion, slowly increasing strength, decreasing swelling, and increasing independence and participation in areas of occupation
• The OT’s role in the process is primarily in educating the client about adaptive techniques for ADLs/IADLs while maintain precautions