I compiled this information from various sources, because my father has had a hip replacement operation, and has been suffering from lower back pain during convalescence. I’m posting it here just in case it could be useful to someone else.
Tiredness and lower back pain after hip replacement surgery
The surgery involves the cutting and manipulation not only of bone but also of soft tissues such as muscles, tendons, nerves, and the capsule that encloses the joint. Such an invasive procedure is tough on the body, and recovering from it takes time. It is normal to be tired; your normal energy levels will return day by day. Don’t be too aggressive in exercising. Your body is working to recover and heal from the surgery even while you are resting.
Lower back pain may be caused by asymmetry in the power of thigh, abdominal and back muscles. Before surgery you were walking asymmetrically (your body was trying to reduce pain by restricting certain movements) and so you will have unconsciously decreased the power of certain muscles, because you used them less on one side. In addition, it is likely that your leg length is now slightly different. This in itself can cause lower back pain. Gradually, as you become more mobile, you will equalize muscle strength and lessen the strain on the lower back.
Something else that happens in hip replacement surgery is that the iliopsoas muscle running from your pelvis to your thigh gets traumatized. This can cause a degree of pelvic tilt for many weeks after surgery, as the iliopsoas remains in a state of contraction, causing imbalance. You may have the sensation of one leg being longer than the other, and this can be caused by this sort of contraction.
In some movements, your low back may tend to bend inwards (arching) as you perform the movement, causing lower back pain. It may help to tighten your stomach muscles during the movement; this helps keep the spine straight.
Often, even two months after surgery, people have pain when getting up out of a chair. The process of alleviating this is lengthy, because your muscles are still compensating for the pain in your hip, even though the operation has removed the source of the pain. Your muscles have been conditioned to misbehave, and many of them have atrophied and weakened in the years before your operation. Your gluteus muscles are weaker, likewise your sartorius, hip adductors and abductors. Quads and hamstrings have to be stretched and strengthened.
Full recovery: 3-6 months.
Total rehabilitation: muscle re-education will only be complete after a year.
In the early months, some good days and some bad days is totally normal. You should notice a gradual improvement over time.
4-6 weeks after surgery: zimmer or crutches
Next 4-6 weeks: a stick
About 10 weeks after surgery: walking without assistance, almost normally.
About 3 months after surgery: most of the soft tissue wounds have healed
3-6 months after surgery: gradual relaxation of hip and leg muscles.
You’ve been given some exercises to perform during convalescence. Remember to bear in mind all the warnings about the movements to avoid!
Don’t overdo it! Avoid high-impact exercises. Take great care whenever you are moving around to avoid tripping. Be careful going up and down stairs.
Initially you will be doing safe range-of-motion activities and muscle strengthening exercises. Exercises should be performed every day. You should allow 15 minutes, two to three times a day to begin; progress to 30 minutes, two to three times a day by the end of six weeks.
Walking is always good. Try to “walk tall,” as straight-backed as possible.
Before you start doing these, you should talk to a physical therapist at the hospital. You have to be advised on when you can start them, and exactly how to do them. They are for hamstrings, quadriceps, hip flexors, illiotibial band, adductors. Once a day or even several times a day. There are also exercises to strengthen the core abdominal muscles.
These exercises will reduce pelvic tilt, decrease back pain, enable you to walk without a limp, equalize hip-and-abdominal strength.
Iron and vitamin supplements could be useful. Drink plenty of fluids. Try to limit your intake of coffee and alcohol.