As we age, tissues deteriorate and metabolism slows, resulting in numerous contributors to knee pain: muscle weakness, cartilage degradation, osteoporosis and obesity.
If your knees are red, warm and swollen after an active day it might be osteoarthritis, or wear and tear of the joints.
While this is the most common cause of knee pain in people over 60, more and more younger patients have been seeing doctors for knee pain.
Knee pains arising from injury and arthritis are similar in profile, the pain worsening with activity and relieving with rest.
The pain can be localised to one aspect of the knee or throughout, reaching to the back or the hip in a sharp, burning or dull manner.
Sometimes the knee might click, lock or give way and those experiencing the pain cannot walk, sleep or rest comfortably.
For the teens to early 30s age bracket, a ligament, sporting or trauma injury is typically to blame, whereas for people in their 30s and 40s, inflammatory (autoimmune or metabolic) and post-traumatic osteoarthritis are the most likely causes of knee pain.
As the knee supports five to seven times a person's body weight, we are increasingly seeing lower joint damage due to obesity.
While knee pain from injury is acute (sudden), and often settles after sufficient rehabilitation and recovery, knee pain from arthritis is often progressive, eventually requiring surgical intervention.
If you suspect you have an infection, fracture or dislocation you should go to the emergency department immediately.
But for a gradually aching knee, your GP will be able to arrange appropriate investigations and diagnosis.
A thorough medical history and physical examination determine the cause of the pain, complemented by at least three weight-bearing X-ray views of the knee, followed by an MRI.
This looks at the bones and soft tissue such as ligaments which can heal or regenerate.
You can also use analgesics such as paracetamol for pain relief however a supervised treatment plan integrating physiotherapy and gradual weight loss will help reduce swelling, facilitate mobility and strengthen the knee muscles and the core of the body.
Can surgery help? Will I need surgery?
If all non-surgical options have been exhausted and knee pain remains, then surgical interventions can take place.
For post-traumatic osteoarthritis, a knee arthroscopy removes damaged tissue, although this is becoming decreasingly common.
'Limited arthroplasty' is another option for the younger patient, replacing only the arthritic component of the knee.
Recovery is quicker, but longevity is shorter compared to a total knee replacement, a well-studied, engineered, and reliable surgical option for generally arthritic knees.
In chronic osteoarthritis, an osteotomy - breaking of the bone and realigning of the joint is ideal for those with a day job requiring heavy weight bearing (such as trades and construction workers) who have arthritis in only one area of the knee.
Pain after a knee replacement can be managed with analgesics, walking aids and physiotherapy.
Driving with the operated knee can generally commence at week six.
Return to manual-type work is realistic eight to 12 weeks post-surgery, and desk-based work can start at four to six weeks.
Almost all patients by one year are happy with their outcome: a replaced knee is a stable knee.
- Today's answer is provided by Sydney orthopaedic surgeon Dr George Gayagay, through HealthShare, a digital company dedicated to improving the health of regional Australians. Submit questions, and find more answers, at healthshare.com.au.