Physiotherapy Management of Total Knee Replacement
Osteoarthritis is a time related joint degenerative condition, the incidence rising rapidly with age, making it the commonest arthritic condition in the world. It develops in various joints in the human body and in some people it particularly affects the large weight-bearing joints of the hip and the knee. As the joint surfaces deteriorate the joint becomes painful, crunches, loses range of motion and becomes difficult to walk on. When conservative measures are not helpful, such as physiotherapy, analgesics, walking aids and weight loss, then knee replacement is considered.
Medical technology developed in the late twentieth century to the stage that joint replacement has become a common and predictable treatment for severely arthritic joints, proving to give the highest quality of life of all medical interventions. Total knee replacement is now a predictable and very successful intervention with good ten year results and beyond. Knee replacement is becoming a more popular operation than hip replacement and as western populations get older the demand will increase.
The osteoarthritic joint surfaces are precisely cut away in knee replacements and metal and plastic surfaces are substituted. These are:
The metal femoral insert to replace the lower end of the femur which is the top half of the knee.
Tibial component. Again a steel alloy part and replaces the damaged tibial surface.
Plastic insert. This is a high density polyethylene and reduces friction between the two main components.
Patellar button. This is also plastic and replaces the back surfaces of the kneecap. If this is not replaced then persistent anterior knee pain can be a problem.
Cement is used as a grout to fix the components but a precise and tight fit is more important in keeping them in place.
After the surgery the physio needs to address the immediate problems that the operation causes in the patient's knee. Inflammation, knee swelling, muscular weakness and pain interfere with the rehabilitation and the physiotherapist initially targets treatment at these problems. A Cryocuff, a compression and cold therapy device, can be used to apply pressure to the swelling and keep up cold therapy for pain relief, with the patient encouraged to take the analgesia regularly. This improves muscle activation as the physio teaches knee flexion and static quadriceps exercises to be performed every hour, to re-establish knee range of movement and muscular control of the joint. By making personal injury claims if the replacement happened following an accident, you may be able to get physiotherapy paid for by the insurance company.
Mobilisation of the patient is the next process in rehabilitation. The physiotherapist assesses the patient's medical status and examines the legs to decide whether mobilisation is appropriate and safe. The quadriceps must be working well enough to provide some knee stability and epidurals can interfere with this for long enough to delay getting up until the effects have worn off. The physio and an assistant get the patient up and establish a good walking pattern with crutches, or a frame for much older people. Normal weight-bearing is usual and this re-establishes normal stresses through the knee, encouraging circulatory return from the leg and normal muscular activation.
Physiotherapy treatment as an outpatient includes working on the range of movement, muscle bulk and strength, balance and functional activities. Physios prescribe inner range quads to strengthen the knee extensors; knee flexion exercises to increase knee bend and knee hang to regain lost extension. Resisted knee flexion is used to increase range via reciprocal inhibition, the resisted movement causing the opposite muscle, the knee extensors, to relax and allow more knee bend. Resistance is provided by manual technique and by using resistance bands. The scar is best mobilised and freed up by tissue massage daily.
Further rehabilitation is more likely to take place in the gym, concentrating on functional activities such as moving from sitting to standing and step ups and strengthening work with Theraband and the gymnastic ball. Work on range of motion will continue using resisted exercises and static bicycling and patients can usefully work on proprioception using the wobble board and other balance related activities. Proprioception is the normal ability of a joint to sense its position in space and this is very important for normal activity and safe walking. Normal gait patterns are encouraged and abnormal patterns corrected.
The information contained within this article was written with the help from a Birmingham Physiotherapist
Author: Jonathan Blood-Smyth