NATURAL HISTORY OF LEG LENGTH DISCREPANCY DURING THE FIRST YEAR AFTER TOTAL HIP ARTHROPLASTY

Abstract

Purpose of the study: Perception of leg length discrepancy after total hip arthroplasty (THA) is a source of patient dissatisfaction. We followed 100 patients with firstintention THA to determine the clinical significance of radiological leg length discrepancy of less than 15 mm.

Materials and Methods: An investigator blinded to the clinical context measured radiological leg length discrepancy in 100 patients after THA. Another investigator evaluated the clinical perception of leg length discrepancy in the same patients 15 days, one month, three months and one year after implantation of their THA.

Results: At 15 days, 73 patients had a clinical perception of leg length discrepancy; 48 at one month; 24 at three months; and 15 at one year. Although the 15 patients (15%) presented leg length discrepancy greater than 10 mm (but less than 15 mm), only four still perceived this difference at one year. At one year, there was no correlation between the length of the discrepancy and clinical perception by the patient. When patients had a length discrepancy greater than 10 mm (but less than 15 mm), the probability of perceiving the difference clinically was not greater (p> 0.05) than for patients whose leg length discrepancy was less than 10 mm. Conversely, patients who perceived a leg length discrepancy at one year had significantly more pronounced (p=0.02) spinal disorders and more permanent hip flexion.

Discussion: Perception of leg length discrepancy is a frequent complaint postoperatively, but rare at one year, even when the radiological difference reaches 15 mm. At one year, the perception of leg length discrepancy is not correlated with the radiological difference but rather with the degree of spinal disorder or permanent hip flexion.

Conclusion: Navigation would have a modest effect on this problem which is probably related in part to spinal rehabilitation.