Populations across the world suffer from osteoarthritis (OA), the most common degenerative joint condition in world, causing large amounts of pain, disability and expense. Western developed populations are ageing and as the incidence of OA rises with each decade of life the impact of this condition will be felt ever more strongly. Less developed countries such as China will soon be joining the countries with ageing populations so the need for effective OA treatment will increase greatly. One of the approaches to managing OA is to perform joint replacement.
Medical interventions can be rated on a scale which calculates the improvement in quality of life which results and here hip replacement comes out top of all treatments. The 1960s saw its development into a standard treatment for hip arthritis but the 21st century has seen the technique evolve into a complex and predictable approach to many hip conditions, with excellent fifteen year plus results. Once conservative treatments have been exhausted due to a worsening joint then joint replacement becomes the standard choice.
Total hip replacement involves removal of the arthritic joint surfaces and their replacement with metal and plastic components. The top of the femur, the ball of the hip joint, is removed and the socket is reamed out to make it bigger to accept the new part. Cement is pressurized into the bony areas and a steel alloy femoral component with a ball and stem is inserted down the femur and a plastic cup of ultra high density polyethylene into the socket. The metal-plastic interface allows very low friction and wear, ensuring a long life for the joint.
Post-operative physiotherapy consists of reviewing the operation note and the medical observations, assessing the patient and instructing them in breathing and leg exercises. The physio assesses the sensibility and muscle power in the legs to exclude problems such as nerve injury, although an epidural can cause temporary loss of feeling and power in the lower body and delay mobilisation. The next physio job is to get the patient up out of the bed with an assistant, stand and walk them as appropriate with elbow crutches or a frame, taking account of the necessary precautions to avoid dislocation.
The patient continues with buttock, hip flexion, quadriceps and foot exercises regularly to encourage normal limb muscle function and help circulation. They take regular analgesia to reduce pain and assist in their ability to mobilise. Once safe they can mobilise independently at least three times a day to have a walk, go to the toilet and wash and dress. Sitting is encouraged as long as the chair is not low and they are not permitted to put their legs up when sitting.
After hip replacement patients require instruction and correction to achieve a normal walking pattern, develop muscular power and improved function. Physiotherapists teach the appropriate gait at the time, often starting with “step to” where the patient moves the walking aid, steps the operated leg forwards and steps up to it with the other leg, a stable and safe pattern. Progression is to ’step through” where the unaffected leg steps beyond the other in an approximation of a normal walking pattern. Patients often progress naturally then to a gait where they move both the crutches and the affected leg forward at the same time and start to walk in a fully natural pattern.
Once they return for their follow up appointment at six weeks after operation patients have often achieved a good gait, reasonable hip strength and returned to some activities of daily living. The physio may advise a stick if they are unsteady, slow or older, and they can gradually regain their previous abilities provided they observe the precautions to prevent hip dislocation:
* Avoid hip flexion over 90 degrees by not sitting down in low seating, not sitting down or standing up too quickly, not bending over to the floor quickly and not crouching.
* Don’t stand on the affected leg and rotate.
* Bending the hip more than 90 degrees should be avoided in such activities as sitting down quickly, sitting in low seats, crouching down or leaning forwards to the floor quickly.
* If an infection develops, for example chest, teeth or bladder, then the doctor should be informed as infections can settle in an artificial joint.
Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and physiotherapists in Sheffield. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.
