Osteoarthritis of the hip often leads to pain in both the hip and knee joints. It’s not so surprising if you think about it, as the body is not comprised of separate components but, rather, it is an interconnected network of muscles, joints and bones. So, if one joint is damaged and causing discomfort, it is likely to affect others nearby.
The link between hip and knee pain
When you have moderate to severe hip pain, you may walk with a limp. This can strain the knees and may cause knee pain. By contrast, if you have damage to your knee joint, this can affect the way you walk which may cause hip discomfort. A number of different factors can be at play in the connection between hip and knee joints. Tight hip flexor muscles pull on the lumber spine and can cause lower back pain. As the body attempts to correct the misalignment, the knees can also be affected. Similarly, a tight iliotibial band can cause friction in the hip and knee joints (Iliotibial Band Syndrome), resulting in pain in both areas.
Because both hip and knee joints are weight-bearing, they can be at risk of stress or overuse injuries which can cause damage and lead to osteoarthritis. As orthopaedic surgeons, it is not unusual to encounter patients with both hip and knee pain, with a root cause of hip osteoarthritis. The normal treatment for severe hip osteoarthritis is a total hip replacement (also called total hip arthroplasty). In some cases, only part of the hip joint needs to be replaced. This is called a partial hip replacement, or partial hip arthroplasty.
Kyoto research: Knee pain improvement following total hip arthroplasty
A team of researchers at Kyoto University in Japan set out to evaluate how frequent and severe knee pain is in patients before and after a total hip replacement and to assess what factors influence knee pain [1].
Methodology: They collected data on total hip replacements in 147 patients with hip osteoarthritis. Levels of hip and knee pain was assessed using a visual analogue scale (VAS), and this was done pre-operatively as well as three, six and 12 months after surgery. The researchers analysed: 1. Changes in the severity of knee pain before and after a total hip replacement; 2. Prevalence of knee pain before and after a total hip replacement; and 3. Factors affecting the severity of knee pain before and after a total hip replacement.
Findings: Their findings showed that knee VAS scores decreased significantly, from 2.2 before surgery to 1.1 at three months. 0.8 at six months and 0.7 at 12 months post-surgery. The prevalence of knee pain also decreased substantially – from 52.3% before total hip replacement to 37.6% at three months, 29.5% at six months and 27.5% 12 months after surgery. The pre-operative hip VAS score positively influenced the pre-operative knee VAS score, while the pre-operative pelvic tilt negatively influenced it. Positive influences on the knee VAS score 12 months after surgery were the Kellgren-Lawrence grade in the knee (used to classify the severity of knee osteoarthritis on an X-ray), the postoperative varus whole-leg alignment (the alignment of the leg after surgery) and the pre-operative knee VAS score.
Conclusions: The researchers concluded that roughly half of the patients they assessed had knee pain before their total hip replacement. This was influenced by the severity of the hip pain patients were experiencing prior to surgery. Both the severity and prevalence of knee pain improved significantly after a total hip replacement. Those patients who were most likely to have continuing knee pain 12 months after a total hip replacement were those with radiological knee osteoarthritis, severe knee pain prior to surgery or postoperative varus alignment.
If you are experiencing hip and knee pain, there can be a number of possible causes including osteoarthritis of the hip or knee. For a detailed diagnosis and advice on the most effective treatment plan, contact us.
Sources
[1] Bone Joint J 2026;108-B(2):160–168.
