When hip overcoverage was more extreme, the odds of developing radiographic hip osteoarthritis rose over the next eight years.
In a large consortium analysis, severe pincer morphology was linked to higher odds of developing radiographic hip osteoarthritis within eight years. Moderate pincer morphology was not significantly associated with new radiographic disease in the main analysis. The risk signal was strongest when “pincer” was defined more strictly.
Quick summary
- What the study found: Severe pincer morphology, defined by a higher lateral centre edge angle threshold, was associated with incident radiographic hip osteoarthritis; moderate pincer morphology was not in the primary analysis.
- Why it matters: It points to a specific hip shape pattern that may help identify people at higher future risk, which could inform monitoring and prevention strategies.
- What to be careful about: The outcome was radiographic disease (X-ray changes), not necessarily painful, symptomatic hip osteoarthritis, and subgroup signals were not definitive.
What was found
The journal article Severe pincer morphology is associated with incident hip osteoarthritis: prospective individual participant data from 18 935 hips from the World COACH consortium pooled data from nine cohorts and followed hips that were free of radiographic hip osteoarthritis at baseline.
Pincer morphology was defined using the lateral centre edge angle, a radiographic measure of how much the hip socket covers the femoral head. Moderate pincer morphology was defined as 40 degrees or more, and severe pincer morphology as 45 degrees or more.
Across 4–8 years of follow-up (average about six years), 352 hips developed incident radiographic hip osteoarthritis. Moderate pincer morphology was not significantly associated with incident disease, while severe pincer morphology was significantly associated.
What it means
The key clinical message is threshold-related: more pronounced acetabular overcoverage tracked with higher future radiographic osteoarthritis risk, while milder overcoverage did not show a clear association in the primary analysis.
This supports a more cautious interpretation of “pincer morphology” as a broad label. In practice, treating all hips above 40 degrees as equally risky may overstate the signal.
Where it fits
The authors note that defining pincer morphology as a static X-ray finding differs from femoroacetabular impingement syndrome, which also requires clinical signs and symptoms. That distinction matters because pain and functional limits often drive care decisions more than radiographic changes alone.
They also highlight potential measurement issues: the lateral centre edge angle can be influenced by osteophytes, which can mimic overcoverage. This study tried to reduce that problem by starting with hips free of radiographic osteoarthritis.
How to use it
For clinicians, severe pincer morphology can be treated as a risk flag for closer follow-up and risk-reduction conversations, especially when other risks are present, such as higher body mass index.
For patients, the actionable idea is load management: build hip strength and stability, and adjust activities that repeatedly provoke high joint loading. The authors also note surgery as a possible strategy to change joint shape, but whether that prevents osteoarthritis remains unknown.
Limits & what we still don’t know
The outcome was radiographic hip osteoarthritis, meaning X-ray changes, which can diverge from symptomatic disease. Generalisability may be limited because the cohorts were from high-income countries.
Subgroup patterns suggested higher risk for moderate pincer morphology in ages 40–50, higher body mass index, and in women, but confidence intervals overlapped and some subgroup analyses were constrained.
More work is needed on pincer subtypes and combinations with other hip shape features, and on prediction models that include symptoms and clinical exam findings.
Closing takeaway
If pincer morphology is going to be used for risk prediction, severity matters. In this dataset, only the more severe overcoverage threshold consistently tracked with later radiographic hip osteoarthritis.
Data in this article is provided by PMC OAI-PMH.
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