Limb length discrepancy in total hip replacement

Author(s): Dr. Ravi Kiran H.G., Dr. Adarsh.T, Dr. Darshan.C.K and Dr. Mruthyunjaya

Abstract: Introduction: Pelvic radiographs are helpful in assessing limb-length discrepancy (LLD) before and after Total Hip Replacement (THR), but are subject to variation. Different methods are used to determine LLDs. As a pelvic reference, both ischial tuberosities and the teardrops are used, and as a femoral reference, the lesser trochanter and center of the femoral head are used Methods: We evaluated 9 cases undergoing THR for degenerative arthritis at JSS hospital from sept2014 to jan2017 for LLD using digital x-rays by 2 different examiners (On digital X-ray AP view of hip, a line is drawn at the level of & parallel to inter teardrop area and intersecting the lesser trochanter on each side. Compare 2 points of intersection & measure difference to determine the amount of limb discrepancy). Results: There was excellent interobsever agreement for radiological measurments (kappa=0.86-0.96) and moderate agreement for manual measurements (kappa=0.44-0.58).Compared to normal limb, the operated limb postoperatively had shortening in 8 cases and lengthening in 1case by radiological method; 8cases had shortening and 1 had same length on manual measurment. In the operated limb compared to pre op, postoperatively 6cases had shortening and 3 had lengthening in radiological measurment; 5cases had shortening, 3cases had lengthening, 1 case had same length on manual measurement. All the patients had perceived limb shortening after surgery. Conclusions: Our data show use of radiological measurement of Limb Length Discrepancy (using intertear drop as pelvic reference and lesser trochanter as femoral reference) is more reliable than manual measurement of Limb Length Discrepancy.

DOI: https://doi.org/10.22271/ortho.2017.v3.i2a.04