The Surprising Link Between Hip Pain and Knee Pain—And Why Hip Surgery Might Help Both

If you're dealing with hip pain, there's a good chance your knee is bothering you too. A groundbreaking study of 149 total hip arthroplasty (hip replacement) surgeries found that 52.3% of patients experienced knee pain before their hip surgery—and remarkably, both problems improved significantly after the hip procedure.

How Common Is Knee Pain Before Hip Surgery?

The research, conducted on 147 patients undergoing primary hip replacements for hip osteoarthritis, tracked pain levels using a visual analogue scale (VAS) before surgery and at three, six, and 12 months afterward. The findings were striking: more than half of hip surgery candidates were dealing with concurrent knee pain, with an average knee pain score of 2.2 out of 10 before their hip procedure.

What makes this discovery particularly interesting is how dramatically knee pain improved following hip surgery, even though the knee itself wasn't treated. Knee pain scores dropped to 1.1 at three months, 0.8 at six months, and just 0.7 at 12 months after hip replacement.

Why Does Hip Surgery Help Knee Pain?

The connection between hip and knee pain isn't coincidental—it's biomechanical. When your hip joint is damaged or arthritic, your body compensates by changing how you walk and distribute weight. This altered gait pattern puts extra stress on your knee joint, creating a domino effect of pain and dysfunction.

The study identified several key factors that influence knee pain before and after hip surgery:

• Preoperative Hip Pain Severity: Patients with more severe hip pain were more likely to experience knee pain before surgery, suggesting the compensation pattern becomes more pronounced as hip problems worsen
• Pelvic Alignment: Preoperative pelvic tilt negatively influenced knee pain, indicating that structural changes in the pelvis affect knee function
• Existing Knee Arthritis: Patients with radiological evidence of knee osteoarthritis were more likely to have persistent knee pain 12 months after hip surgery
• Post-Surgery Leg Alignment: Those who developed varus (inward-angled) whole-leg alignment after surgery were more prone to ongoing knee discomfort

What This Means for Hip Pain Sufferers?

The prevalence of knee pain among hip surgery patients decreased dramatically over time. From the initial 52.3% experiencing knee pain before surgery, only 37.6% still had knee pain at three months, 29.5% at six months, and 27.5% at 12 months post-surgery.

However, certain patients were more likely to experience persistent knee pain even after successful hip replacement. Those with pre-existing knee arthritis, severe preoperative knee pain, or post-surgical alignment issues were at higher risk for ongoing knee discomfort.

This research suggests that if you're experiencing both hip and knee pain, addressing the hip problem first might provide relief for both joints. The interconnected nature of our musculoskeletal system means that fixing one major joint can have positive ripple effects throughout the entire kinetic chain, potentially saving you from needing multiple surgeries or treatments.