Relationship of limb length inequality with radiographic knee and hip osteoarthritis

OBJECTIVE: This study examined the relationship of limb length inequality (LLI) with radiographic hip and knee osteoarthritis (OA) in a large, community-based sample. METHODS: The total study group comprised 926 participants with radiographic knee OA, 796 with radiographic hip OA, and 210 (6.6%) with LLI >or=2cm. The presence of radiographic OA was defined as Kellgren/Lawrence (K/L) grade >or=2. Multiple logistic regression models were used to examine the relationship of LLI with hip and knee OA, while controlling for age, gender, race, body mass index, and history of hip or knee problems (joint injury, fracture, surgery, or congenital anomalies). RESULTS: In unadjusted analyses, participants with LLI were more likely than those without LLI to have radiographic knee OA (45.1% vs 28.3%, P<0.001) and radiographic hip OA (35.2% vs 28.7%, P=0.063). In multiple logistic regression models, knee OA was significantly associated with presence of LLI (adjusted Odds Ratio aOR]=1.80, 95% Confidence Interval 95% CI] 1.29-2.52), but there was no significant relationship between hip OA and LLI (aOR=1.20, 95% CI 0.86-1.67). Among participants with LLI, right hip OA was more common when the contralateral limb was longer than when the ipsilateral limb was longer (30.3% vs 17.5%, P=0.070). CONCLUSION: LLI was associated with radiographic knee OA, controlling for other important variables. Future research should examine the relationship of LLI with hip or knee OA incidence, progression, and symptom severity, as well as the efficacy for LLI corrective treatments in OA.