Back Surgery May Increase Your Hip Replacement Risk—Here's What Researchers Found

A groundbreaking nationwide study has revealed that patients who undergo certain types of lumbar fusion surgery face more than double the risk of needing hip replacement surgery later in life. Researchers tracked patients for up to 10 years and found a significant connection between spine surgery and future hip problems.

What Did the Research Actually Find?

Using data from Korea's National Health Insurance Service, researchers followed patients who had lumbar fusion surgery (LFS) with deformity correction or sacropelvic fixation—procedures that extend the fusion to the sacrum or pelvis. The results were striking: these patients had a 2.26 times higher risk of needing total hip arthroplasty (THA) compared to matched controls who didn't have the surgery.

The study included a comprehensive analysis with a 3-year "washout period" to ensure they weren't counting pre-existing hip problems, plus up to 10 years of follow-up. This makes it one of the most thorough investigations into this connection to date.

Why Does Spine Surgery Affect Your Hips?

The answer lies in how your body works as a connected system. Your spine, pelvis, and hips function together as what researchers call an "interdependent kinetic chain" to maintain balance when you sit, stand, and walk. When you have lumbar fusion surgery, especially when it extends to the sacrum or pelvis, it restricts your pelvis's natural ability to tilt and rotate.

Normally, your pelvis can tilt backward as a compensatory mechanism, helping redistribute mechanical stress across your hip joint. But when spinal fusion limits this movement, your hip joint has to absorb excessive flexion and extension stress that would normally be shared with your pelvis. This altered biomechanical demand may accelerate hip degeneration over time.

Who's Most at Risk?

The research identified several groups who face particularly elevated risks after lumbar fusion surgery:

• Older Adults: Age appeared to be a significant risk factor, with older patients showing greater vulnerability to hip problems following spine surgery
• Women: Female patients demonstrated higher rates of subsequent hip replacement needs compared to men
• Higher Body Mass Index (BMI): Patients with elevated BMI faced increased risk, likely due to additional mechanical stress on the already compromised hip joints
• Higher Income Levels: Interestingly, patients with higher incomes also showed greater risk, possibly due to increased access to elective procedures or different activity levels

Importantly, when researchers looked at total knee arthroplasty (TKA) as a comparison, they found the association was much weaker and not statistically significant. This suggests that the hip joint may be particularly vulnerable to the biomechanical changes that occur after lumbar fusion, rather than this being a general effect on all joints.

The study's findings highlight the importance of long-term monitoring of hip health in patients who undergo lumbar fusion surgery, especially those with the risk factors identified. While the surgery effectively stabilizes the lumbar spine, patients and doctors should be aware of the potential downstream effects on hip joint health when making treatment decisions.