The Shoulder Function Index (SFInX): a clinician-observed outcome measure for people with a proximal humeral fracture

Background Proximal humeral fractures are amongst the most common fractures. Functional recovery is often slow and many people have ongoing disability during activities of daily life. Unidimensional measurement of activity limitations is required to monitor functional progress during rehabilitation. However, currentshoulder measures are multidimensional incorporating constructs such as activities, range of motion and pain into a single scale. Psychometric information of these measures is scarce in this population, and indicate measurement issues with reliability. Therefore, the aim was to develop the clinician-observed Shoulder Function Index (SFInX), a unidimensional, interval-level measure of ‘shoulder function’ based on actual performance of activities, reflecting activity limitations following a proximal humeral fracture. Methods An outcome measure development study was performed including item generation (existing shoulder measures, focus groups) and item selection (selection criteria, importance and feasibility ratings, pilot testing, Rasch analysis). Clinicians (n=15) and people with a proximal humeral fracture (n=13) participated in focus groups. Items were pilot tested (n=12 patients) and validated in a Rasch study. The validation study sample (n=92, 86% female) were recruited between 5 and 52 weeks post-fracture and had a mean age of 63.5 years (SD13.9). Measurements at recruitment and 6 and 7 weeks later were taken in three public metropolitan hospitals or during home visits. Raw SFInX data were analysed with WINSTEPS v3.74 using polytomous Rasch models. Results From 282 generated items, 42 items were selected to be rated by clinicians and patients; 34 items were pilot tested and 16 items were included for Rasch analysis. The final SFInX, developed with the Partial Credit Model, contains 13 items and has the response categories: ‘unable’, ‘partially able’ and ‘able’. It is unidimensional measuring ‘shoulder function’, and can measure from early functional use (drinking from a cup) to independence around the house (lifting items above head, carrying heavy items). Conclusions The SFInX is a promising outcome measure of shoulder function for people with a proximal humeral fracture. It has content relevant to patients and clinicians, is unidimensional and feasible for use in clinical and home settings. In its current form, the SFInX is ready for further psychometric evaluation, and for subsequent use in clinical settings and research. Electronic supplementary material The online version of this article (doi:10.1186/s12891-015-0481-x) contains supplementary material, which is available to authorized users.

the chair on which the person to be tested will be seated, has to be positioned in front of a second chair or plinth. The object is placed on the second chair or plinth. The object on the second chair or plinth is approximately one arm's length behind the person Instruction (patient) reach for and pick up the object on the chair behind you with the hand of the affected arm, bring it forward, and place it onto your lap

Decision rules
Able reaches behind for the object; picks up the object and brings the object forward onto lap using the hand of the affected arm. The strategy chosen is not to be judged (for example, internal/external rotation of the shoulder) The person must remain seated in approximately the starting position; that is, with back supported by the backrest of the chair with the legs forward. Rotating away from the backrest by a large amount from the backrest is not permitted Unable reaches behind for the object, but unable to bring the object forward (for example, due to movement required or weight of object); or unable to reach behind for the object ITEM 9: holding an object for a longer period place the object on the shelf at shoulder level using the hand of your affected arm

Decision rules
Able lifts and places the object on the shelf at shoulder level; movements of the affected arm are unsupported at all times Large compensation by standing on toes, or leaning backward (extension in upper body) with the aim to raise the object is not permitted Unable lifts the object but not high enough to place on the shelf at shoulder level; or less ITEM 12: moving an object above head level Description The ability to perform a prolonged activity above the head, such as hanging up washing or moving books/plates from one side to another on a shelf above the head, is being tested Equipment object (for example, book, bottle; approximately 1.5 kg) Position standing Instruction (clinician) before instructing the person to be tested, the tester is to place the object on a shelf above the head, approximately in line with the position of the person's left shoulder Instruction (patient) take the object in the hand of the affected arm, lift the object off the shelf and move the object from left (shoulder width) to right (shoulder width) and from right to left, and repeat this five times. Try not to rest the arm by putting the object down on the shelf

Decision rules
Able takes and lifts the object off the shelf; maintains this forward flexion-elevation position while making movements sideways ten times (5x left-to-right-to-left) without rests

Partially Able
takes and lifts the object off the shelf; moves the object sideways for less than ten times before needing to rest (for example, by placing the object on the shelf) Unable takes and lifts the object off the shelf only; or unable to lift the object but moves (slides) it sideways on the shelf; or less (for example, cannot reach for the object) ITEM 13: throwing a ball with two hand over-head Description The ability to throw a ball overhead using two hands is being tested Equipment ball (for example, soccerball or basketball) Position standing Instruction (clinician) provide the person to be tested with a ball ensure that the person to be tested holds the ball in front of their body at waist level with two hands (starting position). Stand approximately 5 metres in front of the person to be tested bring the ball with two hands over and behind the head, into your neck. Then, throw the ball forward (by bringing the ball back over the head, then forward) to the tester

Decision rules
Able makes the movements as required; controls the ball with both hands; and creates a forward throw to tester approximately 5 metres away Partially Able makes the movements as required; controls the ball with both hands; then, creates a forward throw, but is unsuccessful in distance (balls drops) or direction (not to tester) OR compensates clearly by flexion of the head OR brings the ball straight above the head or further back (but not into the neck); controls the ball with both hands; and has a successful throw in both distance and direction Unable makes the movements as required only or less (for example, unable to make required movements); unable to make a throwing action

Recommendations for items requiring equipment
Chair Items in which the position is "sitting" have to be performed in a standardised chair without armrests and without rollers. The person to be tested should have the feet on the floor, and the back supported by the backrest. In case testing is performed at a person's home, a kitchen chair is often sufficient and recommended.

Item 1
Cup A cup (no use of handles), mug or little water bottle containing some water or of some weight is recommended. A person has to be able to, or show they are to, drink from the cup.

Item 7 (and 8) Bed
A hospital bed or plinth which is adjustable in height, or a person's own bed at home should be used for testing. A single pillow should be used for comfort. Additional pillows might be needed for a person's comfort in lying position if the person has a certain condition e.g. apnea.
Items 8, 11 and 12 Object 1.5 kg Use of a heavy book, 1.5L bottle water, weight or other object, which weights or approximates 1.5 kg and which is able to be held comfortably in one hand is recommended.

Item 9
Bag + Object 3kg A small box, two 1.5L bottles water, weight or other object which weights or approximates 3 kg, placed in a (shopping) bag is recommended.

Item 10
Object 6kg Use of a pile of heavy books, a box, weight(s) or other object(s) which weight(s) or approximate(s) 6 kg, and can be held in two hands (with shoulders in neutral, elbows in 90 degrees flexion, forearms neutral or supinated) is/are recommended.

Item 13
Ball Use of a soccer/football (or similar) is recommended.