Researchers studied 546 patients who had a specific hip surgery called periacetabular osteotomy (PAO) to treat hip socket problems. They found that about 8% of patients developed stress fractures (small cracks in bones) after surgery. Older patients, those with higher body weight, people who use marijuana or nicotine, and those with certain connective tissue conditions had higher risks. Importantly, patients who developed stress fractures had slower recovery and less improvement in their hip function compared to those without fractures. The good news is that understanding these risk factors helps doctors and patients plan better recovery strategies.

The Quick Take

  • What they studied: Which patients are more likely to develop stress fractures (tiny cracks in bones) after hip socket surgery, and how does this affect their recovery and quality of life.
  • Who participated: 546 patients (mostly women, average age 26 years) who had hip socket surgery between 2016 and 2024. Most were healthy weight, and all were followed for at least one year after surgery.
  • Key finding: About 8 out of 100 patients developed stress fractures after surgery. Older age, higher body weight, marijuana use, nicotine use, and certain genetic conditions that affect connective tissue significantly increased the risk. Those with stress fractures recovered more slowly and had less improvement in hip function.
  • What it means for you: If you’re considering this hip surgery and have any of these risk factors, talk with your surgeon about extra precautions. This might include longer rest periods, physical therapy adjustments, or lifestyle changes before surgery. Having a stress fracture doesn’t mean surgery failed—it just means recovery takes longer.

The Research Details

This was a cohort study, meaning researchers followed a group of patients over time and tracked what happened to them. They looked back at medical records for 546 patients who had hip socket surgery (called periacetabular osteotomy or PAO) performed by one surgeon between February 2016 and October 2024. All patients had X-rays taken at regular intervals after surgery (at 6 weeks, 3 months, and 6 months) to check for stress fractures.

The researchers collected information about each patient before and after surgery, including age, body weight, vitamin D levels, and lifestyle factors like marijuana and nicotine use. They also noted whether patients had certain genetic conditions affecting connective tissue (like Ehlers-Danlos syndrome). After surgery, they measured how well patients were doing using two standard questionnaires that ask about hip pain and function.

To find which factors were most important, they used statistical methods to compare patients who developed stress fractures with those who didn’t. They looked at many possible factors and then focused on the ones that seemed most connected to stress fractures.

Understanding which patients are at higher risk for stress fractures helps surgeons have better conversations with patients before surgery. Instead of viewing stress fractures as a reason to avoid surgery, doctors can use this information to plan personalized recovery strategies. This approach respects patient autonomy while providing realistic expectations about healing.

This study is fairly reliable because it included a large number of patients (546) with consistent follow-up care and regular X-ray monitoring. All surgeries were performed by one experienced surgeon, which reduces variation in surgical technique. However, the study only looked at patients from one practice, so results might not apply equally to all populations. The study is observational rather than experimental, meaning researchers watched what happened naturally rather than randomly assigning patients to different treatments.

What the Results Show

Stress fractures occurred in 8% of patients (37 out of 487) and 7% of individual hips (40 out of 608). When patients had surgery on both hips, 11% developed a stress fracture after the second surgery, and 2% developed stress fractures in both hips.

Several factors significantly increased the risk of stress fractures. For every year of increasing age, the risk went up by 5%. For every unit increase in body mass index (BMI), the risk increased by 9%. The larger the surgical correction of the hip socket angle, the higher the risk—each degree of correction increased risk by 5%. Current marijuana users had about 3 times higher risk than non-users, while current nicotine users had about 6 times higher risk. Patients with genetic conditions affecting connective tissue (Ehlers-Danlos syndrome or hypermobility) had nearly 3 times higher risk.

Patients who developed stress fractures had slower recovery. Their hip function scores improved about 6 points less on one scale and 12 points less on another scale compared to patients without stress fractures. More importantly, fewer patients with stress fractures achieved what doctors call ‘acceptable symptom state’—meaning their hip felt good enough in daily life. About 64% of patients without stress fractures felt their hip was acceptable, compared to only 36% of those with stress fractures.

The study found that having surgery on both hips (bilateral PAO) didn’t significantly change the risk of stress fracture between the first and second surgery, though the numbers were slightly higher after the second surgery. Vitamin D levels, the type of surgical screw used, and whether patients had additional hip arthroscopy during the same surgery were not significantly associated with stress fracture risk. Interestingly, whether it was a patient’s first PAO or a second PAO on the opposite side didn’t make a meaningful difference in stress fracture rates.

Previous research has reported stress fractures after this type of hip surgery, but studies disagreed about how common they are and what causes them. This study is one of the largest to examine this question and is the first to thoroughly investigate lifestyle factors like substance use and genetic conditions. The findings align with general orthopedic knowledge that older age, higher body weight, and smoking increase fracture risk, but the strong association with marijuana use and genetic connective tissue conditions is notable and adds new information to the field.

This study only included patients from one surgeon’s practice, so results might not apply to all hospitals or surgeons. The study was observational, meaning researchers couldn’t prove that these factors directly cause stress fractures—only that they’re associated with them. The number of patients who actually developed stress fractures (37 patients) was relatively small, which makes some of the statistical findings less certain. The study didn’t deeply investigate why certain factors increase risk or explore all possible lifestyle factors that might matter. Finally, most patients were women in their mid-20s, so findings might not apply as well to men or older patients.

The Bottom Line

If you’re considering hip socket surgery and have any of these risk factors—older age, higher body weight, current marijuana or nicotine use, or a genetic condition affecting connective tissue—discuss these with your surgeon before surgery. Your surgeon may recommend: (1) stopping marijuana and nicotine use before and after surgery, (2) weight management if applicable, (3) extended rest periods after surgery before returning to full activity, (4) more frequent physical therapy, and (5) realistic expectations that recovery might take longer. These recommendations are based on moderate-quality evidence and should be personalized to your situation.

This research is most relevant to people considering periacetabular osteotomy for hip socket problems, their families, and their healthcare providers. It’s particularly important for people who have any of the identified risk factors. Surgeons and physical therapists should use this information to counsel patients and adjust rehabilitation plans. People without these risk factors can be reassured that stress fractures are relatively uncommon (8%) and shouldn’t discourage them from having needed surgery.

If a stress fracture does develop, it typically appears within the first 6 months after surgery based on X-ray findings in this study. Recovery from a stress fracture usually takes 3-6 months of modified activity. Even with a stress fracture, most patients eventually improve, but the improvement happens more slowly than in patients without fractures. Full functional recovery may take 12-24 months.

Want to Apply This Research?

  • Track hip pain and function weekly using a simple 0-10 pain scale and note activities that cause discomfort. If you’re at risk for stress fractures, also track weight, substance use (marijuana/nicotine), and adherence to weight-bearing restrictions prescribed by your surgeon.
  • If you have risk factors for stress fractures, use the app to set reminders for: (1) stopping marijuana and nicotine use at least 4 weeks before surgery, (2) following weight-bearing restrictions (like using crutches) for the prescribed period, (3) attending all physical therapy appointments, and (4) gradually increasing activity only as approved by your surgeon.
  • Create a long-term tracking dashboard that monitors hip function scores monthly for the first year, then quarterly. Set alerts if pain increases unexpectedly or if you’re not meeting functional milestones. Share this data with your surgeon at follow-up appointments to catch potential complications early.

This research describes complications that can occur after hip socket surgery in a specific patient population. It is not medical advice and should not replace consultation with your orthopedic surgeon. If you are considering this surgery or have had it, discuss your individual risk factors with your healthcare provider. The findings apply specifically to periacetabular osteotomy and may not apply to other hip procedures. If you experience persistent hip pain, swelling, or difficulty bearing weight after surgery, contact your surgeon immediately as these could indicate a stress fracture or other complication requiring prompt evaluation.