Exercisers who have undergone a total hip replacement (THR) often have trouble returning to normal activity following the procedure. Immediately after a THR is completed, individuals may struggle with maintaining normal coordination of gait, range of motion at the hip, and hip strength.
To address these issues, sports-medicine specialists and physical therapists sometimes recommend that hip-replaced individuals begin their post-operation rehabilitation work with 'underwater-treadmill' exercise, ie, with walking on a special treadmill which is submerged in water. The potential advantage in using such a device is that water provides buoyancy, removing the need for the newly reformulated hip to support full body weight during each step. In addition, the water provides mild resistance to motion, which should strengthen the hip over time (especially the hip-flexor muscles).
To see whether underwater-treadmill workouts might have real value for THR subjects, researchers in the Sports Medicine Institute at Aurora Health Care in Milwaukee, Wisconsin recently worked with 20 post-operative THR patients (10 males, 10 females) from the same orthopaedic surgeon. Six weeks after surgery, all 20 subjects received the standard protocol of physical therapy two times per week for three weeks. However, half of the subjects worked out for an additional 20 minutes per session using an underwater treadmill (the AquaciserÂ¨ or HydroTrackTM).
After the three-week programme was completed, individuals who used the underwater treadmills had significantly greater hip-abduction strength (ie, strength while moving the leg laterally away from the body), compared with control subjects. This is a key finding, because losses in abduction strength are common after THR and can have a strongly negative impact on gait. The scientists involved in this project recommended that individuals who undergo cemented THR surgery should begin exercising on an underwater treadmill, if possible, about four weeks after the operation is completed. Such exercise should improve hip-abduction strength and improve gait stability during the critical rehabilitation period following surgery.