Preoperative Radiographic Assessment of Limb-length Discrepancy in Total Hip Arthroplasty

Abstract

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 À8.0 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. Level of Evidence Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Does Fluoroscopy Improve Acetabular Component Placement in Total Hip Arthroplasty?

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Artroplastia Total da Anca: Estudo Retrospetivo e Comparativo entre a Abordagem Anterior Direta e a Abordagem Posterior

“…26 No que diz respeito à avaliação radiográfica da dismetria, optamos por um método de medição simples e com elevada fiabilidade. 23 A rapidez da recuperação dos doentes do grupo AAD ficou bem patente nos nossos resultados. A melhoria funcional, o menor tempo de internamento e o regresso mais precoce às suas AVD, resultam numa diminuição dos custos hospitalares e aumento da produtividade.…”

“…1); ângulo acetabular -medido entre a linha tangente aos bordos acetabulares e a linha transisquial 22 (Fig. 2); e dismetria dos membros inferiores -distância, em milímetros, medida desde a vertente distal da lágrima até à linha que une os pontos mais largos dos pequenos trocânteres 23 ( Fig. 3).…”