Four Square Step Test Performance in Hip Fracture Patients

Abstract

Background and purpose: Preventing subsequent falls in persons recovering from hip fracture is paramount. The Four Square Step Test (FSST) is a fast, easy measure of dynamic balance, with times more than 15 seconds previously associated with multiple fall risk in older adults. This study investigates among hip fracture patients (1) FSST performance, and how (2) unique population characteristics (such as fracture side) and (3) cognition impact FSST performance.

Methods: Patients with hip fracture (n = 40) 60 years and older came from an ancillary study to a larger randomized controlled trial testing two 16-week in-home physical therapy interventions after completion of usual care rehabilitation. Baseline measurers included: FSST, demographics, fracture characteristics, Modified Mini-Mental State Examination (3MS), Hooper Visual Organization Test (HVOT), and Trails Making Tests (TMT) A and B.

Results: Of 40 patients with hip fracture, 13 did not complete the FSST at baseline and were significantly older (P = .040) and performed worse on cognitive tests (3MS, HVOT, TMT-B; P < .05). Mean FSST time was 24.3 ± 13.1 seconds for the other 27, of whom 7 finished in less than 15 seconds. A significant 3-way interaction was observed, such that those with left-side pertrochanteric fractures who performed poorly on the HVOT did significantly worse on the FSST (P < .01, R2 = 0.93).

Discussion: Almost one-third of patients with hip fracture could not perform the FSST after completing usual care rehabilitation. Inability to perform the FSST was not random, as those without the FSST were physically and cognitively worse than those who did perform the FSST. Among those who could attempt the FSST, few performed well. Cognitive ability related to spatial orientation and fracture characteristics such as fracture side and fracture type has a synergistic effect on FSST performance.

Conclusions: This is one of the first studies to assess the FSST in a population with hip fracture. At 4 months after hip fracture, most patients cannot perform the FSST in less than 15 seconds. Fracture side and fracture type appear important to FSST performance, as does cognition. More work needs to be done longitudinally to study the FSST in patients with hip fracture.

Trial registration: ClinicalTrials.gov NCT01783704.

Figure 1.. CAP-MP Consort Diagram

Consort diagram of the study sample from CAP single study site and sub-sample included in CAP-MP. PUSH and PULSE are the treatment arms of the parent CAP study and are described in published work.^, PUSH was an active intervention arm which received 16 weeks of progressive in-home physical therapy, while PULSE was an active control arm which was administered Transcutaneous Electrical Nerve Stimulation (TENS) in the home for 16 weeks.

Figure 2.. FSST Time in Seconds by Side of Fracture

Best FSST performance in seconds out of two trials at baseline visit stratified by side of fracture (left or right). The dotted line indicates the 15 second cut-point for normative data from community dwelling older adults indicating multiple falls risk. The maximum time is 61 seconds, these individuals failed the test but attempted and completed the maneuvers.

Figure 3.. FSST Time (s) Fracture Side, Fracture Type, and HVOT 3-way Interaction.

As HVOT performance improves, so too does FSST performance time on average. Everyone with left side fractures failed the FSST. Participants with left side pertrochanteric fracture performed the worst. The mechanisms behind this are not yet known.