How to design The Objective Structured Clinical Examination (OSCE) in hand surgery

Examinations are formidable even to the best prepared, for the greatest fool may ask more than the wisest man can answer. (Charles Colton, 1780-1832)

The OSCE has been in place since 1970 and used in Dundee and now widely employed in medical education as a cost effective tool for competence assessment. The literature’s view on this is well summarised as follows (Walther N.K.A. van Mook, 2009) :-

• The ‘magic bullet’ regarding professionalism assessment does not exist.

•        Current ‘state-of-the-art’ in the assessment of professional behaviour is combining multiple methods (triangulation) in varied contexts with multiple observers over a longitudinal trajectory.

•        Current state of the art in education of professional behaviour is assessment with adequate follow-up and with the provision of opportunities for remediation; only assessment without remediation loses ground.

OSCE for fixation in an oblique fracture of the 3^rd metacarpus in a plastic bone model

Aim:

To assess the candidates ability to perform inter fragmentary compression of a fracture of a metacarpus with a 2 mm screw using the lag screw principle.

This OSCE station will test a candidate in the following domains:-

Knowledge: The principles of lag screw fixation

Skills: The ability to accurately and effectively place a lag screw to produce adequate compression across a standardised oblique fracture in a plastic bone model.

Attitude: Attention to detail and methodical planning process.

The Station layout  - on a standard student desk 

Scenario

A standardise oblique fracture created with a saw in the 3 metacarpus of a plastic hand model

Instructions for candidate

1. Stably fix the fracture that has been reproduced in this model using the implants provided.
2. Chose your implant and place it accurately to obtain stable fixation.
3. Use the equipments provided to assist you.
4. Plan you procedure on the paper provided.
5. Use all protective equipment provided.
6. Ensure that you fixation is safe, stable and appropriate.

Instruction to examiner

The time for this station is 15 minutes.

Ensure the candidate chooses his fixation choice and plans it first on paper before proceeding.

1. Choose lag screw technique using a single 2 mm screw
2. Reduces accurately the fracture and holds it with a reduction clamp
3. Chooses the site for placement of the lag screw – right angle to fracture and at least  4 mm from the fracture edges
4. Uses a 2mm drill guide to drill the pilot hole with a 2 mm drill ensuring only the near cortex is drilled
5. Uses the 1.5mm drill sleeve in the pilot hole to drill a 1.5mm hole in the far cortex with a 1.5 mm drill
6. Measures accurately the length of the required screw
7. Countersinks the entry hole to ensure the head of screw will be flushed with the bone
8. Chooses the appropriate screw and confirms the length on the measuring scale
9. Inserts the screws and
10. Confirm compression at fracture site.

The resources required

1. Plastic Bones hand model
2. Cork board with rubber bands to anchor model
3. 2 mm Hand Compact Hand Set including instruments and implants (Synthes)
4. Power drill cordless

Mark sheet

A checklist marking has been used here as it allows for quantification of results and provides objectivity and by adding a heavy weight age to the choice of fixation it shows the importance of choosing the best options for fixation of an oblique fracture.

A global rating was not used as it did not allow for specific areas of assessment and the checklist allows for more accurate feedback for the candidates in areas of weakness for remedial learning.

                                                                                    Max                                         Actual

Ensure the candidate chooses the right fixation technique – a lag screw technique using a single 2 mm screw	4
Reduces accurately the fracture and holds it with a reduction clamp	1/2
Chooses the site for placement of the lag screw – right angle to fracture and at least  4 mm from the fracture edges	1/2
Uses a 2mm drill guide to drill the pilot hole with a 2 mm drill ensuring only the near cortex is drilled	1/2
Uses the 1.5mm drill sleeve in the pilot hole to drill a 1.5mm hole in the far cortex with a 1.5 mm drill	1/2
Measures accurately the length of the required screw	1/2
Countersinks the entry hole to ensure the head of screw will be flushed with the bone	1/2
Chooses the appropriate screw and confirms the length on the measuring scale	1/2
Inserts the screws in line with drill hole	1/2
Confirm compression at fracture site.	2

Max                                                                             10

Advantages of this OSCE

• Each candidate undergoes the same assessment material and scoring system under identical conditions

• Versatile format to assess any part of curriculum in hand surgery

• Potentially provides both candidate and trainer with detailed analysis of performance

• Potential for objective feedback

Disadvantages of this OSCE

• Resource intensive needing planning and resources like equipment, personnel and time

• Not a holistic assessment tool as this only test for psychomotor skills

• Examiners need to be trained to assess objectively

References

Walther N.K.A. van Mook et al

General considerations regarding assessment of professional behaviour, European Journal of Internal Medicine, Volume 20, Issue 4, July 2009, Pages e90-e9