Effects of a home-based physical rehabilitation program on tibial bone structure, density and strength after hip fracture : a secondary analysis of a randomized controlled trial

Abstract

Weight-bearing physical activity may decrease or prevent bone deterioration after hip fracture. This study investigated theeffects of a home-based physical rehabilitation program on tibial bone traits in older hip fracture patients. A population-basedclinical sample of men and women operated for hip fracture (mean age 80 years, 78% women) was randomly assigned into anintervention (n¼40) and a standard care control group (n¼41) on average 10 weeks postfracture. The intervention groupparticipated in a 12-month home-based rehabilitation intervention, including evaluation and modification of environmentalhazards, guidance for safe walking, nonpharmacological pain management, motivational physical activity counseling, and aprogressive, weight-bearing home exercise program comprising strengthening exercises for the lower legs, balance training,functional exercises, and stretching. All participants received standard care. Distal tibia (5% proximal to the distal end plate)compressive bone strength index (BSI; g2/cm4), total volumetric BMD (vBMDTOT;mg/cm3), and total area (CSATOT;mm2), as wellas midtibia (55%) strength–strain index (SSI; mm3), cortical vBMD (vBMDCO;mg/cm3), and ratio of cortical to total area (CSACO/CSATOT)were assessed in both legs by pQCT at baseline and at 3, 6, and 12 months. The intervention had no effect (group time)on either the distal or midtibial bone traits. At the distal site, BSI of both legs, vBMDTOTof the fractured side, and CSATOTof thenonfractured side decreased significantly over time in both groups 0.7% to 3.1% (12 months,p<0.05). At the midshaft site,CSACO/CSATOTand SSI of both legs, and vBMDCOof the fractured leg, decreased significantly over time in both groups 1.1% to1.9% (12 months,p<0.05). Trabecular and cortical bone traits of the tibia on the fractured and the nonfractured sidedeteriorated throughout follow-up. The home-based physical rehabilitation intervention aimed at promoting mobility recoverywas unable to prevent bone deterioration in older people after hip fracture.