Upper limb prosthesis in PP Trans humeral amputation Measurements, Cast and Rectification

1) Patient Examination Check the passive and active range of movement of the gléno-humeral joint. Make a muscle testing. Check that the patient is able to operate straps and fastenings. ( sound upper limb) Check for any painful areas

2) Measurements : sound side Axilla or acromion process to olecranon with elbow flexed. Axilla or acromion process to thumb tip with elbow straight. Hand size, for cosmetic reasons, the prosthetic hand should be slightly smaller than the sound hand. Show the patient a selection of suitable hands and hooks prior to the casting stage.

Measurement: amputated side Axilla or acromion process to end of stump. Stump circumferences. if required on an elbow disarticulation patient, ML measures at and above epicondyles.

Measurement chart

Socket design 1) The proximal trim line of the socket passes over the top of the shoulder girdle. 2) The socket is trimmed below the top of the shoulder girdle.

Socket design 1) The proximal trim line of the socket passes over the top of the shoulder girdle. = some weight is taken over the shoulder thus reducing e the load on the harness. it limits the amount of shoulder abduction.

Socket design 2) The socket is trimmed below the top of the shoulder girdle. Its allows a greater range of abduction but places a higher load on the harness

Socket design Both designs rely on anterior and posterior wings which extend medially to the line drawn down through the axilla. Any gapping of the wings reduces their effectiveness. Before casting , the P&O has to decide which type of socket will be manufactured.

Cast technique A thin casting stockinet is put onto the stump. Mark any painful or bony areas. Mark the shoulder girdle's bony prominences as clavicle & acromion process. Draw the trim lines on the stockinet. Apply pressure on top of the pectoral muscles just below the clavicle.

Cast technique Apply proper and even tension of POP bandages during casting. Cast irregularities make the removal of the cast more difficult.

Cast technique: slab cast Each slab is composed of 3 layers of POP bandage ( width 15cm). one slab for axilla ( 6 layers) one slab for the medial wall one slab for the anterior one slab for the posterior one slab for the lateral and shoulder 6. a roll of POP bandage ( 10 cm) is connecting the slabs together

Cast technique : slab cast Each slab should be slightly longer than the stump. The axilla slab has to be 3 times the length of the axilla. Start casting by positioning the axilla slab in order to shape the medial trim line. Then position the medial slab : this slab has to overlap the axilla slab. During casting, beware of stump abduction.

Cast technique : slab cast The shoulder slab should reach from anterior axilla area to posterior axilla area. In order to flatten the medial wall, the patient is keeping the stump against the trunk (ribcage). The sub-clavicular fossa and the clavicle need to be well shaped.

Cast technique: slab cast The cast is removed while the POP bandages have set. Draw and cut the trim lines. For an "over the shoulder socket design", the medial trim line is cut straight above the edge of the axilla. It allows a good suspension and abduction.

Plaster socket fitting Ensure that the patient can flex and extend stump without rubbing at medial trim line level. For long stump the medial wall can be lowered ( 1 cm).

Plaster check socket The "wings" should not be wider than half of the distance from the axilla to the corner of the neck

Alignment of the negative cast Lateral and anterior alignement build down line should be marked. For short stumps (abducted) we can use modified build down line

Rectification of the positive cast Minimal rectification is needed Ensure that marks and build down lines are transferred to the cast The distal end does not usually need a build-up

Rectification of the positive cast Ensure that the medial wall has been slightly flattened during the casting process. This allows the arm to adduct comfortably against the rib cage

Rectification of the positive cast All production measures are taken from the medial trim line at the axilla. If this trim line is lowered in the case of a patient with a long stump, the amount lowered should be noted as it will affect the production measurements.

Rectification of the positive cast The wings should be smoothened, ensure that the edges flare slightly outwards slightly to prevent them digging into the body. The acromion and clavicle will need built up