BACKGROUND: Pelvic radiographs are helpful in assessing limb-length discrepancy (LLD) before and after THA 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. QUESTIONS/PURPOSES: We validated the different methods for preoperative radiographic measurement of LLDs and evaluated their reliability. PATIENTS AND METHODS: LLDs were measured on full-leg radiographs for 52 patients (29 men, 23 women) with osteoarthritis (OA) of the hip and compared with different methods for measuring LLDs on AP radiographs of the pelvis. RESULTS: The true LLD varied from -8.0 to 9.1 mm. When the biischial line was used as a pelvic reference, the LLD measured on AP pelvis radiographs was different from the true LLD. No difference was found when the interteardrop line was used as a pelvic reference. There was substantial interobserver agreement when the lesser trochanter was used as a femoral reference (kappa = 0.66-0.70) and excellent interobserver and intraobserver agreement for all other measurements (kappa = 0.84-0.93). CONCLUSIONS: Our data show use of the biischial line as a pelvic reference should be discouraged and the interteardrop line is a better alternative. The center of the femoral head is a more reliable femoral landmark compared with the lesser trochanter.
BACKGROUND: Pelvic radiographs are helpful in assessing limb-length discrepancy (LLD) before and after THA 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. QUESTIONS/PURPOSES: We validated the different methods for preoperative radiographic measurement of LLDs and evaluated their reliability. PATIENTS AND METHODS: LLDs were measured on full-leg radiographs for 52 patients (29 men, 23 women) with osteoarthritis (OA) of the hip and compared with different methods for measuring LLDs on AP radiographs of the pelvis. RESULTS: The true LLD varied from -8.0 to 9.1 mm. When the biischial line was used as a pelvic reference, the LLD measured on AP pelvis radiographs was different from the true LLD. No difference was found when the interteardrop line was used as a pelvic reference. There was substantial interobserver agreement when the lesser trochanter was used as a femoral reference (kappa = 0.66-0.70) and excellent interobserver and intraobserver agreement for all other measurements (kappa = 0.84-0.93). CONCLUSIONS: Our data show use of the biischial line as a pelvic reference should be discouraged and the interteardrop line is a better alternative. The center of the femoral head is a more reliable femoral landmark compared with the lesser trochanter.
Authors: Brandon S Beamer; Jordan H Morgan; Christopher Barr; Michael J Weaver; Mark S Vrahas Journal: Clin Orthop Relat Res Date: 2014-09-20 Impact factor: 4.176
Authors: Markus Weber; Michael Woerner; Robert Springorum; Ernst Sendtner; Alexander Hapfelmeier; Joachim Grifka; Tobias Renkawitz Journal: Clin Orthop Relat Res Date: 2014-06-26 Impact factor: 4.176
Authors: Hervé Ouanezar; Thomas Jalaguier; Florent Franck; Vincent Pibarot; Hugo Bothorel; Mo Saffarini; Jean-Pierre Piton Journal: Ann Transl Med Date: 2019-03