Background/Purpose:

While it is well known that knee pain and radiographic knee osteoarthritis (OA) are often discordant, little is known of the concordance of hip pain with the presence of radiographic hip OA.  From a prevalence study of hip osteoarthritis done in Framingham, Massachusetts, we examined the relationship between hip pain and radiographic hip OA. 

Methods:

We performed a community based study of OA among persons age 50 – 79 living in Framingham in 2002 – 2005 with recruitment by random digit dialing and subjects studied without respect to joint pain or arthritis.  Anteroposterior standing long-limb radiographs of the lower extremities including the pelvis were obtained and were read for radiographic hip OA(ROA) by two trained physicians.  Cases of ROA were confirmed by an experienced musculoskeletal radiologist.  ROA was defined as Kellgren-Lawrence score ≥ 2.  Using a homunculus in which the hip joint was depicted as a large circle in the groin, participants were asked whether they had hip pain on most days.  Those who said ‘yes’ were defined as having hip pain.  If they had hip pain, subjects then answered another question asking location of pain: groin, front of the leg (anterior), outside the leg (lateral), lower back, or buttocks.  Also, many participants had a standardized hip exam during which they were asked about pain during passive internal rotation.  We examined sensitivity (Sn), specificity (Sp) and positive and negative predictive values (PPV, NPV) of different constellations of hip pain and location specific pain with ROA.

Results :

Radiographs from 948 participants were evaluated including 419 men and 529 women.  The average age was 63.5 years (s.d. 9 yrs).  One hundred sixty participants (87 men and 73 women) had ROA (16.9%) .  One hundred eighty-two participants (19.2%) had hip pain.  Only 22% of participants with hip pain had ROA in the same hip whereas 15.7% of participants without hip pain had ROA in that hip.  The Sn of hip pain for ROA was 25%, the Sp of hip pain for ROA was 82%, and the PPV for hip pain was 22% (See table).  However, when we restricted analyses to those with hip pain who localized this pain to the groin, the PPV rose to 38.1%.  But of those with ROA, only 6.3% had hip and groin pain.   For hip pain with anterior pain, the PPV was 27.8%, and the Sn was 7%.  The diagnostic test performance for other sites of pain was poorer.  If a participant had hip pain and pain with passive internal rotation, 18% had ROA.

Conclusion :

We found poor agreement between hip pain on most days and radiographic OA in the ipsilateral hip. Many older persons with frequent hip pain including pain in the groin or front of the thigh did not have positive x-rays in that hip, and many persons with radiographic OA did not have hip pain.  Of the constellation of questions for hip pain, those with the highest PPV were hip pain with groin or anterior pain.