Influence of Self-reported Limb Length Discrepancy on Function and Satisfaction 6 Years After Total Hip Replacement

Abstract

Osteoarthritis (OA) of the hip is a major cause of restricted locomotor activity and functional disability. Total hip replacement (THR) is a valuable procedure for the management of end stage arthritis and is effective in improving quality of life and physical function and alleviating pain. Leg length discrepancy (LLD) is an adverse outcome of THR. There are two types of LLD—apparent and true. Apparent LLD is pelvic obliquity, which occurs after THR due to tight hip abductors and usually resolves within 6 months with abductor stretching. In contrast, true LLD reflects unequal bone length (e.g. due to bone loss, growth alteration, subsidence). Love and Wright reported an 18% incidence of limb lengthening greater than 1.5 cm after unilateral THR, with 6% of patients treated with a shoe lift on the non-operated leg. A similar study by Woo and Morrey found an average lengthening of 1 cm in a series of 333 cases. Although LLD as much as 2 cm is common among the normal population, discrepancies after THR may lead to patient dissatisfaction and functional impairment. While a large number of subjects are satisfied with their pain relief and improved function following THR, LLD arising from either lengthened or shortened femur following THR is a significant source of patient dissatisfaction. Lengthening of the leg can contribute to the development of nerve palsy, specifically of the sciatic nerve palsy, leading to functional limitations. Discrepancies in limb leg have also been associated with alterations in gait, chronic low back pain, and chronic hip pain. Hence, LLD following THR has been a leading cause of litigation and may lead to revision surgery. Even relatively minor differences in leg length can be detected by patients and may impact satisfaction with surgery, especially when patients are required to wear a lift in the contralateral shoe to correct the discrepancy. Most studies of LLD after THR have focused on methods to minimize the problem or on techniques to assess true leg length differences. Few studies have examined the long-term influence of LLD on satisfaction and function. The purpose of this study was to determine if perceived LLD influences function and satisfaction six years after primary THR, adjusting for other predictors of functional status and patient satisfaction.