Knee Muscle Strength and Visual Acuity are the Most Important Modifiable Predictors of Falls in Patients after Hip Fracture Surgery: A Prospective Study

Dora T. Y. Yau, Raymond C. K. Chung, Marco Y. C. Pang

Our purpose was to identify risk factors for falls among older adults who had recently undergone hip fracture surgery. The subjects in this study were 69 older adults (aged 65 years or more) who had sustained a hip fracture and were admitted to an orthopedic rehabilitation ward after surgery. Potential fall risk factors were assessed using the physiological profile assessment, timed-up-and-go test, berg balance test, and activities-specific balance confidence scale at discharge from the hospital. Each individual was followed for a period of 6 months to obtain information on the incidence of falls. Receiver operating characteristic curves were constructed to determine the optimal cutoff score for each potential risk factor identified. Multivariate logistic regression was then used to identify the significant predictors of falls and their odds ratios (ORs). During the 6-month follow-up period, 10 of the 69 patients experienced one or more falls. The results showed that fallers were older than nonfallers (p=0.009). Fallers also had poorer performance in the high-contrast visual acuity test (p=0.015) and lower knee flexor (p=0.021) and knee extensor (p=0.005) muscle strength values. Multivariate logistic regression analysis showed that high-contrast visual acuity (cutoff score Z=-2.280, OR=6.14, 95% CI 1.13-33.29, p=0.035) and knee extensor muscle strength (cutoff score Z=-1.835, OR=4.81, 95% CI 1.04-22.33, p=0.045) were predictors of falls. Poor visual acuity and knee muscle weakness are modifiable predictors of falls and should be the key target areas in fall-prevention programs for older adults with hip fractures.