Moderate leg length discrepancy: a long-term risk factor for hip osteoarthritis?

Area of Science:

• Orthopedics
• Gerontology
• Biomechanics

Background:

• Leg length discrepancy (LLD) is a potential contributor to hip osteoarthritis (OA).
• The precise influence of LLD on OA progression, particularly in older adults, requires further investigation.
• This study specifically examines moderate LLD (≥10 mm) and its association with asymmetrical OA distribution.

Purpose of the Study:

• To investigate the correlation between moderate leg length discrepancy (LLD) and the progression of hip osteoarthritis (OA) in individuals over 65 years old.
• To analyze the impact of LLD on the asymmetrical distribution of hip OA.
• To understand the biomechanical implications of LLD on joint loading and OA development.

Main Methods:

• Retrospective analysis of 220 patients aged 65+ from full-length standing X-rays.
• Measurement of tibial and femoral lengths bilaterally and assessment of hip OA severity using the Tönnis classification.
• Statistical analysis using Pearson's Chi-squared test and linear regression to determine the correlation between LLD and OA distribution.

Main Results:

• 18% of the study sample exhibited a leg length discrepancy (LLD) of 10 mm or greater.
• A significant correlation (p=0.002) was found between LLD and asymmetrical hip osteoarthritis (OA) distribution.
• Linear regression indicated that each millimeter of LLD was associated with a 0.74-unit increase in OA severity difference between hips, with greater OA in the shorter limb.

Conclusions:

• Moderate leg length discrepancy (LLD) is significantly associated with contralateral hip osteoarthritis (OA) in the elderly population.
• Asymmetrical joint loading due to LLD plays a crucial biomechanical role in hip OA progression.
• Early identification and targeted management of LLD are recommended to mitigate OA progression in older adults.