Unit 5 - Upper Limb Joint Replacement Flashcards
Typically, patients undergoing upper limb joint replacement will have been diagnosed with which condition?
Rheumatoid arthritis Osteoarthritis Osteonecrosis Post-traumatic arthritis Fractures
Why are problems with the spine or lower limb normally given priority over the upper limb?
- RA of the cervical spine may cause instability and can be associated with significant or progressive neurological symptoms
- Successful hip/knee replacements will reduce the need for the upper body to support body weight during walking
In the upper limb why are distal joints normally given priority?
- To allow restoration of hand function
- Problems in distal joints may compromise physiotherapy post-surgery in more proximal joints
- More functional improvement is gained the more distal the joint
Why do some surgeons prefer to replace the shoulder joint before any other upper limb joint?
- Shoulder pain is more troublesome at night
- An immobile shoulder will cause abnormal loadings at the elbow
- Rehabilitation of other upper limb joints can be simplified with a pain-free shoulder
What range of shoulder abduction is generally achieved from unconstrained designs?
90 to 135 degrees
What 3 synovial joints make up the shoulder?
Glenohumeral
Acromioclavicular
Sternoclavicular
What bone-on-muscle-on-bone joint is important to the mobility of the shoulder?
Scapulothoracic
What 4 muscles make up the rotator cuff?
Supraspinatus
Infraspinatus
Subscapularis
Teres minor
How could an unconstrained shoulder design be converted to a semi-constrained design?
By fitting a hooded glenoid
What are the disadvantages of a semi constrained shoulder design compared to an unconstrained design?
- Restricted range of motion
2. More frequent glenoid component loosening
What material is used to construct. the glenoid component of a Neer type shoulder prosthesis?
Polyethylene
What type of designs are most constrained shoulder replacements?
Ball-in-socket
What 3 articulations does the elbow consist of?
- Humeroulnar
- Humeroradial
- Proximal radioulnar
How much movement does a normal elbow joint allow?
140 degrees flexion
70 degrees pronation
80 degrees supination
In flexion which ligament provides over 50% of the elbow’s stability?
Medial collateral ligament
What are the main problems of uniaxial hinged elbow prostheses?
Loosening
Loss of bone stock
Name the 3 cobalt chromes parts present in Dee’s design?
Humeral component
Ulnar component
Axis pin
What is the possible range of flexion in Dee’s design?
0-150 degrees of flexion
What are the 2 types of wrist joint prostheses?
- Flexible hinge
2. Total wrist
How much movement does a normal wrist allow?
80-90 degrees flexion
70-80 degrees extension
35 degrees adduction
15-20 degrees abduction
For most daily activities how much flexion and extension of the wrist is required as a minimum?
10 degrees flexion
35 degrees extension
What is a flexible hinge wrist prosthesis constructed from?
Silicone elastomer (rubber)
What percentage of flexible wrist prostheses have been found to tear on the sharp bony edges of the medullary canal?
20%
What are the two main problems associated with total wrist prostheses?
- Loosening
2. Stress-shielding of the distal radius
